Add genesis block hash to NetworkGraph

[rust-lightning] / lightning / src / routing / network_graph.rs

// This file is Copyright its original authors, visible in version control
// history.
//
// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// You may not use this file except in accordance with one or both of these
// licenses.

//! The top-level network map tracking logic lives here.

use bitcoin::secp256k1::key::PublicKey;
use bitcoin::secp256k1::Secp256k1;
use bitcoin::secp256k1;

use bitcoin::hashes::sha256d::Hash as Sha256dHash;
use bitcoin::hashes::Hash;
use bitcoin::blockdata::script::Builder;
use bitcoin::blockdata::transaction::TxOut;
use bitcoin::blockdata::opcodes;
use bitcoin::hash_types::BlockHash;

use chain;
use chain::Access;
use ln::features::{ChannelFeatures, NodeFeatures};
use ln::msgs::{DecodeError, ErrorAction, LightningError, RoutingMessageHandler, NetAddress, MAX_VALUE_MSAT};
use ln::msgs::{ChannelAnnouncement, ChannelUpdate, NodeAnnouncement, OptionalField};
use ln::msgs::{QueryChannelRange, ReplyChannelRange, QueryShortChannelIds, ReplyShortChannelIdsEnd};
use ln::msgs;
use util::ser::{Writeable, Readable, Writer};
use util::logger::Logger;
use util::events;

use std::{cmp, fmt};
use std::sync::{RwLock, RwLockReadGuard};
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Mutex;
use std::collections::BTreeMap;
use std::collections::btree_map::Entry as BtreeEntry;
use std::collections::HashMap;
use std::ops::Deref;
use bitcoin::hashes::hex::ToHex;

/// Maximum number of short_channel_id values that can be encoded in a
/// single reply_channel_range or query_short_channel_ids messages when
/// using raw encoding. The maximum value ensures that the 8-byte SCIDs
/// fit inside the maximum size of the Lightning message, 65535-bytes.
const MAX_SHORT_CHANNEL_ID_BATCH_SIZE: usize = 8000;

/// Maximum number of reply_channel_range messages we will allow in
/// reply to a query_channel_range. This value creates an upper-limit 
/// on the number of SCIDs we process in reply to a single query.
const MAX_REPLY_CHANNEL_RANGE_PER_QUERY: usize = 250;

/// Represents the network as nodes and channels between them
#[derive(PartialEq)]
pub struct NetworkGraph {
        genesis_hash: BlockHash,
        channels: BTreeMap<u64, ChannelInfo>,
        nodes: BTreeMap<PublicKey, NodeInfo>,
}

/// A simple newtype for RwLockReadGuard<'a, NetworkGraph>.
/// This exists only to make accessing a RwLock<NetworkGraph> possible from
/// the C bindings, as it can be done directly in Rust code.
pub struct LockedNetworkGraph<'a>(pub RwLockReadGuard<'a, NetworkGraph>);

/// Receives and validates network updates from peers,
/// stores authentic and relevant data as a network graph.
/// This network graph is then used for routing payments.
/// Provides interface to help with initial routing sync by
/// serving historical announcements.
pub struct NetGraphMsgHandler<C: Deref, L: Deref> where C::Target: chain::Access, L::Target: Logger {
        secp_ctx: Secp256k1<secp256k1::VerifyOnly>,
        /// Representation of the payment channel network
        pub network_graph: RwLock<NetworkGraph>,
        chain_access: Option<C>,
        full_syncs_requested: AtomicUsize,
        pending_events: Mutex<Vec<events::MessageSendEvent>>,
        chan_range_query_tasks: Mutex<HashMap<PublicKey, ChanRangeQueryTask>>,
        scid_query_tasks: Mutex<HashMap<PublicKey, ScidQueryTask>>,
        logger: L,
}

impl<C: Deref, L: Deref> NetGraphMsgHandler<C, L> where C::Target: chain::Access, L::Target: Logger {
        /// Creates a new tracker of the actual state of the network of channels and nodes,
        /// assuming a fresh network graph.
        /// Chain monitor is used to make sure announced channels exist on-chain,
        /// channel data is correct, and that the announcement is signed with
        /// channel owners' keys.
        pub fn new(genesis_hash: BlockHash, chain_access: Option<C>, logger: L) -> Self {
                NetGraphMsgHandler {
                        secp_ctx: Secp256k1::verification_only(),
                        network_graph: RwLock::new(NetworkGraph::new(genesis_hash)),
                        full_syncs_requested: AtomicUsize::new(0),
                        chain_access,
                        pending_events: Mutex::new(vec![]),
                        chan_range_query_tasks: Mutex::new(HashMap::new()),
                        scid_query_tasks: Mutex::new(HashMap::new()),
                        logger,
                }
        }

        /// Creates a new tracker of the actual state of the network of channels and nodes,
        /// assuming an existing Network Graph.
        pub fn from_net_graph(chain_access: Option<C>, logger: L, network_graph: NetworkGraph) -> Self {
                NetGraphMsgHandler {
                        secp_ctx: Secp256k1::verification_only(),
                        network_graph: RwLock::new(network_graph),
                        full_syncs_requested: AtomicUsize::new(0),
                        chain_access,
                        pending_events: Mutex::new(vec![]),
                        chan_range_query_tasks: Mutex::new(HashMap::new()),
                        scid_query_tasks: Mutex::new(HashMap::new()),
                        logger,
                }
        }

        /// Take a read lock on the network_graph and return it in the C-bindings
        /// newtype helper. This is likely only useful when called via the C
        /// bindings as you can call `self.network_graph.read().unwrap()` in Rust
        /// yourself.
        pub fn read_locked_graph<'a>(&'a self) -> LockedNetworkGraph<'a> {
                LockedNetworkGraph(self.network_graph.read().unwrap())
        }

        /// Enqueues a message send event for a batch of short_channel_ids
        /// in a task.
        fn finalize_query_short_ids(&self, task: &mut ScidQueryTask) {
                let scid_size = std::cmp::min(task.short_channel_ids.len(), MAX_SHORT_CHANNEL_ID_BATCH_SIZE);
                let mut short_channel_ids: Vec<u64> = Vec::with_capacity(scid_size);
                for scid in task.short_channel_ids.drain(..scid_size) {
                        short_channel_ids.push(scid);
                }

                log_debug!(self.logger, "Sending query_short_channel_ids peer={}, batch_size={}", log_pubkey!(task.node_id), scid_size);

                // enqueue the message to the peer
                let mut pending_events = self.pending_events.lock().unwrap();
                pending_events.push(events::MessageSendEvent::SendShortIdsQuery {
                        node_id: task.node_id.clone(),
                        msg: QueryShortChannelIds {
                                chain_hash: task.chain_hash.clone(),
                                short_channel_ids,
                        }
                });
        }
}

impl<'a> LockedNetworkGraph<'a> {
        /// Get a reference to the NetworkGraph which this read-lock contains.
        pub fn graph(&self) -> &NetworkGraph {
                &*self.0
        }
}


macro_rules! secp_verify_sig {
        ( $secp_ctx: expr, $msg: expr, $sig: expr, $pubkey: expr ) => {
                match $secp_ctx.verify($msg, $sig, $pubkey) {
                        Ok(_) => {},
                        Err(_) => return Err(LightningError{err: "Invalid signature from remote node".to_owned(), action: ErrorAction::IgnoreError}),
                }
        };
}

impl<C: Deref + Sync + Send, L: Deref + Sync + Send> RoutingMessageHandler for NetGraphMsgHandler<C, L> where C::Target: chain::Access, L::Target: Logger {
        fn handle_node_announcement(&self, msg: &msgs::NodeAnnouncement) -> Result<bool, LightningError> {
                self.network_graph.write().unwrap().update_node_from_announcement(msg, &self.secp_ctx)?;
                Ok(msg.contents.excess_data.is_empty() && msg.contents.excess_address_data.is_empty())
        }

        fn handle_channel_announcement(&self, msg: &msgs::ChannelAnnouncement) -> Result<bool, LightningError> {
                self.network_graph.write().unwrap().update_channel_from_announcement(msg, &self.chain_access, &self.secp_ctx)?;
                log_trace!(self.logger, "Added channel_announcement for {}{}", msg.contents.short_channel_id, if !msg.contents.excess_data.is_empty() { " with excess uninterpreted data!" } else { "" });
                Ok(msg.contents.excess_data.is_empty())
        }

        fn handle_htlc_fail_channel_update(&self, update: &msgs::HTLCFailChannelUpdate) {
                match update {
                        &msgs::HTLCFailChannelUpdate::ChannelUpdateMessage { ref msg } => {
                                let _ = self.network_graph.write().unwrap().update_channel(msg, &self.secp_ctx);
                        },
                        &msgs::HTLCFailChannelUpdate::ChannelClosed { short_channel_id, is_permanent } => {
                                self.network_graph.write().unwrap().close_channel_from_update(short_channel_id, is_permanent);
                        },
                        &msgs::HTLCFailChannelUpdate::NodeFailure { ref node_id, is_permanent } => {
                                self.network_graph.write().unwrap().fail_node(node_id, is_permanent);
                        },
                }
        }

        fn handle_channel_update(&self, msg: &msgs::ChannelUpdate) -> Result<bool, LightningError> {
                self.network_graph.write().unwrap().update_channel(msg, &self.secp_ctx)?;
                Ok(msg.contents.excess_data.is_empty())
        }

        fn get_next_channel_announcements(&self, starting_point: u64, batch_amount: u8) -> Vec<(ChannelAnnouncement, Option<ChannelUpdate>, Option<ChannelUpdate>)> {
                let network_graph = self.network_graph.read().unwrap();
                let mut result = Vec::with_capacity(batch_amount as usize);
                let mut iter = network_graph.get_channels().range(starting_point..);
                while result.len() < batch_amount as usize {
                        if let Some((_, ref chan)) = iter.next() {
                                if chan.announcement_message.is_some() {
                                        let chan_announcement = chan.announcement_message.clone().unwrap();
                                        let mut one_to_two_announcement: Option<msgs::ChannelUpdate> = None;
                                        let mut two_to_one_announcement: Option<msgs::ChannelUpdate> = None;
                                        if let Some(one_to_two) = chan.one_to_two.as_ref() {
                                                one_to_two_announcement = one_to_two.last_update_message.clone();
                                        }
                                        if let Some(two_to_one) = chan.two_to_one.as_ref() {
                                                two_to_one_announcement = two_to_one.last_update_message.clone();
                                        }
                                        result.push((chan_announcement, one_to_two_announcement, two_to_one_announcement));
                                } else {
                                        // TODO: We may end up sending un-announced channel_updates if we are sending
                                        // initial sync data while receiving announce/updates for this channel.
                                }
                        } else {
                                return result;
                        }
                }
                result
        }

        fn get_next_node_announcements(&self, starting_point: Option<&PublicKey>, batch_amount: u8) -> Vec<NodeAnnouncement> {
                let network_graph = self.network_graph.read().unwrap();
                let mut result = Vec::with_capacity(batch_amount as usize);
                let mut iter = if let Some(pubkey) = starting_point {
                                let mut iter = network_graph.get_nodes().range((*pubkey)..);
                                iter.next();
                                iter
                        } else {
                                network_graph.get_nodes().range(..)
                        };
                while result.len() < batch_amount as usize {
                        if let Some((_, ref node)) = iter.next() {
                                if let Some(node_info) = node.announcement_info.as_ref() {
                                        if node_info.announcement_message.is_some() {
                                                result.push(node_info.announcement_message.clone().unwrap());
                                        }
                                }
                        } else {
                                return result;
                        }
                }
                result
        }

        fn should_request_full_sync(&self, _node_id: &PublicKey) -> bool {
                //TODO: Determine whether to request a full sync based on the network map.
                const FULL_SYNCS_TO_REQUEST: usize = 5;
                if self.full_syncs_requested.load(Ordering::Acquire) < FULL_SYNCS_TO_REQUEST {
                        self.full_syncs_requested.fetch_add(1, Ordering::AcqRel);
                        true
                } else {
                        false
                }
        }

        fn query_channel_range(&self, their_node_id: &PublicKey, chain_hash: BlockHash, first_blocknum: u32, number_of_blocks: u32) -> Result<(), LightningError> {
                // We must ensure that we only have a single in-flight query
                // to the remote peer. If we already have a query, then we fail
                let mut query_range_tasks_lock = self.chan_range_query_tasks.lock().unwrap();
                let query_range_tasks = &mut *query_range_tasks_lock;
                if query_range_tasks.contains_key(their_node_id) {
                        return Err(LightningError {
                                err: String::from("query_channel_range already in-flight"),
                                action: ErrorAction::IgnoreError,
                        });
                }

                // Construct a new task to keep track of the query until the full
                // range query has been completed
                let task = ChanRangeQueryTask::new(their_node_id, chain_hash, first_blocknum, number_of_blocks);
                query_range_tasks.insert(their_node_id.clone(), task);

                // Enqueue the message send event
                log_debug!(self.logger, "Sending query_channel_range peer={}, first_blocknum={}, number_of_blocks={}", log_pubkey!(their_node_id), first_blocknum, number_of_blocks);
                let mut pending_events = self.pending_events.lock().unwrap();
                pending_events.push(events::MessageSendEvent::SendChannelRangeQuery {
                        node_id: their_node_id.clone(),
                        msg: QueryChannelRange {
                                chain_hash,
                                first_blocknum,
                                number_of_blocks,
                        },
                });
                Ok(())
        }

        /// A query should only request channels referring to unspent outputs.
        /// This method does not validate this requirement and expects the
        /// caller to ensure SCIDs are unspent.
        fn query_short_channel_ids(&self, their_node_id: &PublicKey, chain_hash: BlockHash, short_channel_ids: Vec<u64>) -> Result<(), LightningError> {
                // Create a new task or add to the existing task
                let mut query_scids_tasks_lock = self.scid_query_tasks.lock().unwrap();
                let query_scids_tasks = &mut *query_scids_tasks_lock;

                // For an existing task we append the short_channel_ids which will be sent when the
                // current in-flight batch completes.
                if let Some(task) = query_scids_tasks.get_mut(their_node_id) {
                        task.add(short_channel_ids);
                        return Ok(());
                }

                // For a new task we create the task with short_channel_ids and send the first
                // batch immediately.
                query_scids_tasks.insert(their_node_id.clone(), ScidQueryTask::new(
                        their_node_id,
                        chain_hash.clone(),
                        short_channel_ids,
                ));
                let task = query_scids_tasks.get_mut(their_node_id).unwrap();
                self.finalize_query_short_ids(task);
                return Ok(());
        }

        fn handle_reply_channel_range(&self, their_node_id: &PublicKey, msg: &ReplyChannelRange) -> Result<(), LightningError> {
                log_debug!(self.logger, "Handling reply_channel_range peer={}, first_blocknum={}, number_of_blocks={}, full_information={}, scids={}", log_pubkey!(their_node_id), msg.first_blocknum, msg.number_of_blocks, msg.full_information, msg.short_channel_ids.len(),);

                // First we obtain a lock on the task hashmap. In order to avoid borrowing issues
                // we will access the task as needed.
                let mut query_range_tasks = self.chan_range_query_tasks.lock().unwrap();

                // If there is no currently executing task then we have received
                // an invalid message and will return an error
                if query_range_tasks.get(their_node_id).is_none() {
                        return Err(LightningError {
                                err: String::from("Received unknown reply_channel_range message"),
                                action: ErrorAction::IgnoreError,
                        });
                }

                // Now that we know we have a task, we can extract a few values for use
                // in validations without having to access the task repeatedly
                let (task_chain_hash, task_first_blocknum, task_number_of_blocks, task_received_first_block, task_received_last_block, task_number_of_replies) = {
                        let task = query_range_tasks.get(their_node_id).unwrap();
                        (task.chain_hash, task.first_blocknum, task.number_of_blocks, task.received_first_block, task.received_last_block, task.number_of_replies)
                };

                // Validate the chain_hash matches the chain_hash we used in the query.
                // If it does not, then the message is malformed and we return an error
                if msg.chain_hash != task_chain_hash {
                        query_range_tasks.remove(their_node_id);
                        return Err(LightningError {
                                err: String::from("Received reply_channel_range with invalid chain_hash"),
                                action: ErrorAction::IgnoreError,
                        });
                }

                // Validate that the remote node maintains up-to-date channel
                // information for chain_hash. Some nodes use the full_information
                // flag to indicate multi-part messages so we must check whether
                // we received information as well.
                if !msg.full_information && msg.short_channel_ids.len() == 0 {
                        query_range_tasks.remove(their_node_id);
                        return Err(LightningError {
                                err: String::from("Received reply_channel_range with no information available"),
                                action: ErrorAction::IgnoreError,
                        });
                }

                // Calculate the last block for the message and the task
                let msg_last_block = last_blocknum(msg.first_blocknum, msg.number_of_blocks);
                let task_last_block = last_blocknum(task_first_blocknum, task_number_of_blocks);

                // On the first message...
                if task_received_first_block.is_none() {
                        // The replies can be a superset of the queried block range, but the
                        // replies must include our requested query range. We check if the
                        // start of the replies is greater than the start of our query. If
                        // so, the start of our query is excluded and the message is malformed.
                        if msg.first_blocknum > task_first_blocknum {
                                query_range_tasks.remove(their_node_id);
                                return Err(LightningError {
                                        err: String::from("Failing reply_channel_range with invalid first_blocknum"),
                                        action: ErrorAction::IgnoreError,
                                });
                        }

                        // Next, we ensure the reply has at least some information matching
                        // our query. If the received last_blocknum is less than our query's
                        // first_blocknum then the reply does not encompass the query range
                        // and the message is malformed.
                        if msg_last_block < task_first_blocknum {
                                query_range_tasks.remove(their_node_id);
                                return Err(LightningError {
                                        err: String::from("Failing reply_channel_range with non-overlapping first reply"),
                                        action: ErrorAction::IgnoreError,
                                });
                        }

                        // Capture the first block and last block so that subsequent messages
                        // can be validated.
                        let task = query_range_tasks.get_mut(their_node_id).unwrap();
                        task.received_first_block = Some(msg.first_blocknum);
                        task.received_last_block = Some(msg_last_block);
                }
                // On subsequent message(s)...
                else {
                        // We need to validate the sequence of the reply message is expected.
                        // Subsequent messages must set the first_blocknum to the previous
                        // message's first_blocknum plus number_of_blocks. There is discrepancy
                        // in implementation where some resume on the last sent block. We will
                        // loosen the restriction and accept either, and otherwise consider the
                        // message malformed and return an error.
                        let task_received_last_block = task_received_last_block.unwrap();
                        if msg.first_blocknum != task_received_last_block && msg.first_blocknum != task_received_last_block + 1 {
                                query_range_tasks.remove(their_node_id);
                                return Err(LightningError {
                                        err: String::from("Failing reply_channel_range with invalid sequence"),
                                        action: ErrorAction::IgnoreError,
                                });
                        }

                        // Next we check to see that we have received a realistic number of
                        // reply messages for a query. This caps the allocation exposure
                        // for short_channel_ids that will be batched and sent in query channels.
                        if task_number_of_replies + 1 > MAX_REPLY_CHANNEL_RANGE_PER_QUERY {
                                query_range_tasks.remove(their_node_id);
                                return Err(LightningError {
                                        err: String::from("Failing reply_channel_range due to excessive messages"),
                                        action: ErrorAction::IgnoreError,
                                });
                        }

                        // Capture the last_block in our task so that subsequent messages
                        // can be validated.
                        let task = query_range_tasks.get_mut(their_node_id).unwrap();
                        task.number_of_replies += 1;
                        task.received_last_block = Some(msg_last_block);
                }

                // We filter the short_channel_ids to those inside the query range.
                // The most significant 3-bytes of the short_channel_id are the block.
                {
                        let mut filtered_short_channel_ids: Vec<u64> = msg.short_channel_ids.clone().into_iter().filter(|short_channel_id| {
                                let block = short_channel_id >> 40;
                                return block >= query_range_tasks.get(their_node_id).unwrap().first_blocknum as u64 && block <= task_last_block as u64;
                        }).collect();
                        let task = query_range_tasks.get_mut(their_node_id).unwrap();
                        task.short_channel_ids.append(&mut filtered_short_channel_ids);
                }

                // The final message is indicated by a last_blocknum that is equal to
                // or greater than the query's last_blocknum.
                if msg_last_block >= task_last_block {
                        log_debug!(self.logger, "Completed query_channel_range: peer={}, first_blocknum={}, number_of_blocks={}", log_pubkey!(their_node_id), task_first_blocknum, task_number_of_blocks);

                        // We can now fire off a query to obtain routing messages for the
                        // accumulated short_channel_ids.
                        {
                                let task = query_range_tasks.get_mut(their_node_id).unwrap();
                                let mut short_channel_ids = Vec::new();
                                std::mem::swap(&mut short_channel_ids, &mut task.short_channel_ids);
                                self.query_short_channel_ids(their_node_id, task.chain_hash, short_channel_ids)?;
                        }

                        // We can remove the query range task now that the query is complete.
                        query_range_tasks.remove(their_node_id);
                }
                Ok(())
        }

        /// When a query is initiated the remote peer will begin streaming
        /// gossip messages. In the event of a failure, we may have received
        /// some channel information. Before trying with another peer, the
        /// caller should update its set of SCIDs that need to be queried.
        fn handle_reply_short_channel_ids_end(&self, their_node_id: &PublicKey, msg: &ReplyShortChannelIdsEnd) -> Result<(), LightningError> {
                log_debug!(self.logger, "Handling reply_short_channel_ids_end peer={}, full_information={}", log_pubkey!(their_node_id), msg.full_information);

                // First we obtain a lock on the task hashmap. In order to avoid borrowing issues
                // we will access the task as needed.
                let mut query_short_channel_ids_tasks = self.scid_query_tasks.lock().unwrap();

                // If there is no existing task then we have received an unknown
                // message and should return an error.
                if query_short_channel_ids_tasks.get(their_node_id).is_none() {
                        return Err(LightningError {
                                err: String::from("Unknown reply_short_channel_ids_end message"),
                                action: ErrorAction::IgnoreError,
                        });
                }

                // If the reply's chain_hash does not match the task's chain_hash then
                // the reply is malformed and we should return an error.
                if msg.chain_hash != query_short_channel_ids_tasks.get(their_node_id).unwrap().chain_hash {
                        query_short_channel_ids_tasks.remove(their_node_id);
                        return Err(LightningError {
                                err: String::from("Received reply_short_channel_ids_end with incorrect chain_hash"),
                                action: ErrorAction::IgnoreError
                        });
                }

                // If the remote node does not have up-to-date information for the
                // chain_hash they will set full_information=false. We can fail
                // the result and try again with a different peer.
                if !msg.full_information {
                        query_short_channel_ids_tasks.remove(their_node_id);
                        return Err(LightningError {
                                err: String::from("Received reply_short_channel_ids_end with no information"),
                                action: ErrorAction::IgnoreError
                        });
                }

                // If we have more scids to process we send the next batch in the task
                {
                        let task = query_short_channel_ids_tasks.get_mut(their_node_id).unwrap();
                        if task.short_channel_ids.len() > 0 {
                                self.finalize_query_short_ids(task);
                                return Ok(());
                        }
                }

                // Otherwise the task is complete and we can remove it
                log_debug!(self.logger, "Completed query_short_channel_ids peer={}", log_pubkey!(their_node_id));
                query_short_channel_ids_tasks.remove(their_node_id);
                Ok(())
        }

        /// There are potential DoS vectors when handling inbound queries.
        /// Handling requests with first_blocknum very far away may trigger repeated
        /// disk I/O if the NetworkGraph is not fully in-memory.
        fn handle_query_channel_range(&self, _their_node_id: &PublicKey, _msg: &QueryChannelRange) -> Result<(), LightningError> {
                // TODO
                Err(LightningError {
                        err: String::from("Not implemented"),
                        action: ErrorAction::IgnoreError,
                })
        }

        /// There are potential DoS vectors when handling inbound queries.
        /// Handling requests with first_blocknum very far away may trigger repeated
        /// disk I/O if the NetworkGraph is not fully in-memory.
        fn handle_query_short_channel_ids(&self, _their_node_id: &PublicKey, _msg: &QueryShortChannelIds) -> Result<(), LightningError> {
                // TODO
                Err(LightningError {
                        err: String::from("Not implemented"),
                        action: ErrorAction::IgnoreError,
                })
        }
}

impl<C: Deref, L: Deref> events::MessageSendEventsProvider for NetGraphMsgHandler<C, L>
where
        C::Target: chain::Access,
        L::Target: Logger,
{
        fn get_and_clear_pending_msg_events(&self) -> Vec<events::MessageSendEvent> {
                let mut ret = Vec::new();
                let mut pending_events = self.pending_events.lock().unwrap();
                std::mem::swap(&mut ret, &mut pending_events);
                ret
        }
}

/// Safely calculates the last_blocknum given a first_blocknum and
/// number_of_blocks by returning the u32::MAX-1 if there is an overflow
fn last_blocknum(first_blocknum: u32, number_of_blocks: u32) -> u32 {
        match first_blocknum.checked_add(number_of_blocks) {
                Some(val) => val - 1,
                None => 0xffff_ffff - 1,
        }
}

/// Maintains state for a channel range query that we initiated.
/// The query may result in one or more reply_channel_range messages
/// being received. This struct helps determine the status of the query
/// when there are multiple replies. It also collects results for initiating
/// SCID queries.
///
/// The task is complete and can be cleaned up when a reply meets or
/// exceeds the last block in the query. The collected SCIDs in the task
/// can be used to generate an ScidQueryTask.
///
/// A query may fail if the recipient does not maintain up-to-date
/// information for the chain or if the recipient fails to reply within
/// a reasonable amount of time. In either event, the query can be
/// re-initiated with a different peer.
pub struct ChanRangeQueryTask {
        /// The public key of the node we will be sending queries to
        pub node_id: PublicKey,
        /// The genesis hash of the blockchain being queried
        pub chain_hash: BlockHash,
        /// The height of the first block for the channel UTXOs being queried
        pub first_blocknum: u32,
        /// The number of blocks to include in the query results
        pub number_of_blocks: u32,
        /// Tracks the number of reply messages we have received
        pub number_of_replies: usize,
        /// The height of the first block received in a reply. This value
        /// should be less than or equal to the first_blocknum requested in
        /// the query_channel_range. This allows the range of the replies to
        /// contain, but not necessarily strictly, the queried range.
        pub received_first_block: Option<u32>,
        /// The height of the last block received in a reply. This value
        /// will get incrementally closer to the target of
        /// first_blocknum plus number_of_blocks from the query_channel_range.
        pub received_last_block: Option<u32>,
        /// Contains short_channel_ids received in one or more reply messages.
        /// These will be sent in one ore more query_short_channel_ids messages
        /// when the task is complete.
        pub short_channel_ids: Vec<u64>,
}

impl ChanRangeQueryTask {
        /// Constructs a new GossipQueryRangeTask
        pub fn new(their_node_id: &PublicKey, chain_hash: BlockHash, first_blocknum: u32, number_of_blocks: u32) -> Self {
                ChanRangeQueryTask {
                        node_id: their_node_id.clone(),
                        chain_hash,
                        first_blocknum,
                        number_of_blocks,
                        number_of_replies: 0,
                        received_first_block: None,
                        received_last_block: None,
                        short_channel_ids: vec![],
                }
        }
}

/// Maintains state when sending one or more short_channel_ids messages
/// to a peer. Only a single SCID query can be in-flight with a peer. The
/// number of SCIDs per query is limited by the size of a Lightning message
/// payload. When querying a large number of SCIDs (results of a large
/// channel range query for instance), multiple query_short_channel_ids
/// messages need to be sent. This task maintains the list of awaiting
/// SCIDs to be queried.
///
/// When a successful reply_short_channel_ids_end message is received, the
/// next batch of SCIDs can be sent. When no remaining SCIDs exist in the
/// task, the task is complete and can be cleaned up.
///
/// The recipient may reply indicating that up-to-date information for the
/// chain is not maintained. A query may also fail to complete within a
/// reasonable amount of time. In either event, the short_channel_ids
/// can be queried from a different peer after validating the set of
/// SCIDs that still need to be queried.
pub struct ScidQueryTask {
        /// The public key of the node we will be sending queries to
        pub node_id: PublicKey,
        /// The genesis hash of the blockchain being queried
        pub chain_hash: BlockHash,
        /// A vector of short_channel_ids that we would like routing gossip
        /// information for. This list will be chunked and sent to the peer
        /// in one or more query_short_channel_ids messages.
        pub short_channel_ids: Vec<u64>,
}

impl ScidQueryTask {
        /// Constructs a new GossipQueryShortChannelIdsTask
        pub fn new(their_node_id: &PublicKey, chain_hash: BlockHash, short_channel_ids: Vec<u64>) -> Self {
                ScidQueryTask {
                        node_id: their_node_id.clone(),
                        chain_hash,
                        short_channel_ids,
                }
        }

        /// Adds short_channel_ids to the pending list of short_channel_ids
        /// to be sent in the next request. You can add additional values
        /// while a query is in-flight. These new values will be sent once
        /// the active query has completed.
        pub fn add(&mut self, mut short_channel_ids: Vec<u64>) {
                self.short_channel_ids.append(&mut short_channel_ids);
        }
}

#[derive(PartialEq, Debug)]
/// Details about one direction of a channel. Received
/// within a channel update.
pub struct DirectionalChannelInfo {
        /// When the last update to the channel direction was issued.
        /// Value is opaque, as set in the announcement.
        pub last_update: u32,
        /// Whether the channel can be currently used for payments (in this one direction).
        pub enabled: bool,
        /// The difference in CLTV values that you must have when routing through this channel.
        pub cltv_expiry_delta: u16,
        /// The minimum value, which must be relayed to the next hop via the channel
        pub htlc_minimum_msat: u64,
        /// The maximum value which may be relayed to the next hop via the channel.
        pub htlc_maximum_msat: Option<u64>,
        /// Fees charged when the channel is used for routing
        pub fees: RoutingFees,
        /// Most recent update for the channel received from the network
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
        pub last_update_message: Option<ChannelUpdate>,
}

impl fmt::Display for DirectionalChannelInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "last_update {}, enabled {}, cltv_expiry_delta {}, htlc_minimum_msat {}, fees {:?}", self.last_update, self.enabled, self.cltv_expiry_delta, self.htlc_minimum_msat, self.fees)?;
                Ok(())
        }
}

impl_writeable!(DirectionalChannelInfo, 0, {
        last_update,
        enabled,
        cltv_expiry_delta,
        htlc_minimum_msat,
        htlc_maximum_msat,
        fees,
        last_update_message
});

#[derive(PartialEq)]
/// Details about a channel (both directions).
/// Received within a channel announcement.
pub struct ChannelInfo {
        /// Protocol features of a channel communicated during its announcement
        pub features: ChannelFeatures,
        /// Source node of the first direction of a channel
        pub node_one: PublicKey,
        /// Details about the first direction of a channel
        pub one_to_two: Option<DirectionalChannelInfo>,
        /// Source node of the second direction of a channel
        pub node_two: PublicKey,
        /// Details about the second direction of a channel
        pub two_to_one: Option<DirectionalChannelInfo>,
        /// The channel capacity as seen on-chain, if chain lookup is available.
        pub capacity_sats: Option<u64>,
        /// An initial announcement of the channel
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
        pub announcement_message: Option<ChannelAnnouncement>,
}

impl fmt::Display for ChannelInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "features: {}, node_one: {}, one_to_two: {:?}, node_two: {}, two_to_one: {:?}",
                   log_bytes!(self.features.encode()), log_pubkey!(self.node_one), self.one_to_two, log_pubkey!(self.node_two), self.two_to_one)?;
                Ok(())
        }
}

impl_writeable!(ChannelInfo, 0, {
        features,
        node_one,
        one_to_two,
        node_two,
        two_to_one,
        capacity_sats,
        announcement_message
});


/// Fees for routing via a given channel or a node
#[derive(Eq, PartialEq, Copy, Clone, Debug)]
pub struct RoutingFees {
        /// Flat routing fee in satoshis
        pub base_msat: u32,
        /// Liquidity-based routing fee in millionths of a routed amount.
        /// In other words, 10000 is 1%.
        pub proportional_millionths: u32,
}

impl Readable for RoutingFees{
        fn read<R: ::std::io::Read>(reader: &mut R) -> Result<RoutingFees, DecodeError> {
                let base_msat: u32 = Readable::read(reader)?;
                let proportional_millionths: u32 = Readable::read(reader)?;
                Ok(RoutingFees {
                        base_msat,
                        proportional_millionths,
                })
        }
}

impl Writeable for RoutingFees {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                self.base_msat.write(writer)?;
                self.proportional_millionths.write(writer)?;
                Ok(())
        }
}

#[derive(PartialEq, Debug)]
/// Information received in the latest node_announcement from this node.
pub struct NodeAnnouncementInfo {
        /// Protocol features the node announced support for
        pub features: NodeFeatures,
        /// When the last known update to the node state was issued.
        /// Value is opaque, as set in the announcement.
        pub last_update: u32,
        /// Color assigned to the node
        pub rgb: [u8; 3],
        /// Moniker assigned to the node.
        /// May be invalid or malicious (eg control chars),
        /// should not be exposed to the user.
        pub alias: [u8; 32],
        /// Internet-level addresses via which one can connect to the node
        pub addresses: Vec<NetAddress>,
        /// An initial announcement of the node
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
        pub announcement_message: Option<NodeAnnouncement>
}

impl Writeable for NodeAnnouncementInfo {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                self.features.write(writer)?;
                self.last_update.write(writer)?;
                self.rgb.write(writer)?;
                self.alias.write(writer)?;
                (self.addresses.len() as u64).write(writer)?;
                for ref addr in &self.addresses {
                        addr.write(writer)?;
                }
                self.announcement_message.write(writer)?;
                Ok(())
        }
}

impl Readable for NodeAnnouncementInfo {
        fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NodeAnnouncementInfo, DecodeError> {
                let features = Readable::read(reader)?;
                let last_update = Readable::read(reader)?;
                let rgb = Readable::read(reader)?;
                let alias = Readable::read(reader)?;
                let addresses_count: u64 = Readable::read(reader)?;
                let mut addresses = Vec::with_capacity(cmp::min(addresses_count, MAX_ALLOC_SIZE / 40) as usize);
                for _ in 0..addresses_count {
                        match Readable::read(reader) {
                                Ok(Ok(addr)) => { addresses.push(addr); },
                                Ok(Err(_)) => return Err(DecodeError::InvalidValue),
                                Err(DecodeError::ShortRead) => return Err(DecodeError::BadLengthDescriptor),
                                _ => unreachable!(),
                        }
                }
                let announcement_message = Readable::read(reader)?;
                Ok(NodeAnnouncementInfo {
                        features,
                        last_update,
                        rgb,
                        alias,
                        addresses,
                        announcement_message
                })
        }
}

#[derive(PartialEq)]
/// Details about a node in the network, known from the network announcement.
pub struct NodeInfo {
        /// All valid channels a node has announced
        pub channels: Vec<u64>,
        /// Lowest fees enabling routing via any of the enabled, known channels to a node.
        /// The two fields (flat and proportional fee) are independent,
        /// meaning they don't have to refer to the same channel.
        pub lowest_inbound_channel_fees: Option<RoutingFees>,
        /// More information about a node from node_announcement.
        /// Optional because we store a Node entry after learning about it from
        /// a channel announcement, but before receiving a node announcement.
        pub announcement_info: Option<NodeAnnouncementInfo>
}

impl fmt::Display for NodeInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "lowest_inbound_channel_fees: {:?}, channels: {:?}, announcement_info: {:?}",
                   self.lowest_inbound_channel_fees, &self.channels[..], self.announcement_info)?;
                Ok(())
        }
}

impl Writeable for NodeInfo {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                (self.channels.len() as u64).write(writer)?;
                for ref chan in self.channels.iter() {
                        chan.write(writer)?;
                }
                self.lowest_inbound_channel_fees.write(writer)?;
                self.announcement_info.write(writer)?;
                Ok(())
        }
}

const MAX_ALLOC_SIZE: u64 = 64*1024;

impl Readable for NodeInfo {
        fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NodeInfo, DecodeError> {
                let channels_count: u64 = Readable::read(reader)?;
                let mut channels = Vec::with_capacity(cmp::min(channels_count, MAX_ALLOC_SIZE / 8) as usize);
                for _ in 0..channels_count {
                        channels.push(Readable::read(reader)?);
                }
                let lowest_inbound_channel_fees = Readable::read(reader)?;
                let announcement_info = Readable::read(reader)?;
                Ok(NodeInfo {
                        channels,
                        lowest_inbound_channel_fees,
                        announcement_info,
                })
        }
}

impl Writeable for NetworkGraph {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
                self.genesis_hash.write(writer)?;
                (self.channels.len() as u64).write(writer)?;
                for (ref chan_id, ref chan_info) in self.channels.iter() {
                        (*chan_id).write(writer)?;
                        chan_info.write(writer)?;
                }
                (self.nodes.len() as u64).write(writer)?;
                for (ref node_id, ref node_info) in self.nodes.iter() {
                        node_id.write(writer)?;
                        node_info.write(writer)?;
                }
                Ok(())
        }
}

impl Readable for NetworkGraph {
        fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NetworkGraph, DecodeError> {
                let genesis_hash: BlockHash = Readable::read(reader)?;
                let channels_count: u64 = Readable::read(reader)?;
                let mut channels = BTreeMap::new();
                for _ in 0..channels_count {
                        let chan_id: u64 = Readable::read(reader)?;
                        let chan_info = Readable::read(reader)?;
                        channels.insert(chan_id, chan_info);
                }
                let nodes_count: u64 = Readable::read(reader)?;
                let mut nodes = BTreeMap::new();
                for _ in 0..nodes_count {
                        let node_id = Readable::read(reader)?;
                        let node_info = Readable::read(reader)?;
                        nodes.insert(node_id, node_info);
                }
                Ok(NetworkGraph {
                        genesis_hash,
                        channels,
                        nodes,
                })
        }
}

impl fmt::Display for NetworkGraph {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                writeln!(f, "Network map\n[Channels]")?;
                for (key, val) in self.channels.iter() {
                        writeln!(f, " {}: {}", key, val)?;
                }
                writeln!(f, "[Nodes]")?;
                for (key, val) in self.nodes.iter() {
                        writeln!(f, " {}: {}", log_pubkey!(key), val)?;
                }
                Ok(())
        }
}

impl NetworkGraph {
        /// Returns all known valid channels' short ids along with announced channel info.
        ///
        /// (C-not exported) because we have no mapping for `BTreeMap`s
        pub fn get_channels<'a>(&'a self) -> &'a BTreeMap<u64, ChannelInfo> { &self.channels }
        /// Returns all known nodes' public keys along with announced node info.
        ///
        /// (C-not exported) because we have no mapping for `BTreeMap`s
        pub fn get_nodes<'a>(&'a self) -> &'a BTreeMap<PublicKey, NodeInfo> { &self.nodes }

        /// Get network addresses by node id.
        /// Returns None if the requested node is completely unknown,
        /// or if node announcement for the node was never received.
        ///
        /// (C-not exported) as there is no practical way to track lifetimes of returned values.
        pub fn get_addresses<'a>(&'a self, pubkey: &PublicKey) -> Option<&'a Vec<NetAddress>> {
                if let Some(node) = self.nodes.get(pubkey) {
                        if let Some(node_info) = node.announcement_info.as_ref() {
                                return Some(&node_info.addresses)
                        }
                }
                None
        }

        /// Creates a new, empty, network graph.
        pub fn new(genesis_hash: BlockHash) -> NetworkGraph {
                Self {
                        genesis_hash,
                        channels: BTreeMap::new(),
                        nodes: BTreeMap::new(),
                }
        }

        /// For an already known node (from channel announcements), update its stored properties from a
        /// given node announcement.
        ///
        /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
        /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
        /// routing messages from a source using a protocol other than the lightning P2P protocol.
        pub fn update_node_from_announcement<T: secp256k1::Verification>(&mut self, msg: &msgs::NodeAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<(), LightningError> {
                let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
                secp_verify_sig!(secp_ctx, &msg_hash, &msg.signature, &msg.contents.node_id);
                self.update_node_from_announcement_intern(&msg.contents, Some(&msg))
        }

        /// For an already known node (from channel announcements), update its stored properties from a
        /// given node announcement without verifying the associated signatures. Because we aren't
        /// given the associated signatures here we cannot relay the node announcement to any of our
        /// peers.
        pub fn update_node_from_unsigned_announcement(&mut self, msg: &msgs::UnsignedNodeAnnouncement) -> Result<(), LightningError> {
                self.update_node_from_announcement_intern(msg, None)
        }

        fn update_node_from_announcement_intern(&mut self, msg: &msgs::UnsignedNodeAnnouncement, full_msg: Option<&msgs::NodeAnnouncement>) -> Result<(), LightningError> {
                match self.nodes.get_mut(&msg.node_id) {
                        None => Err(LightningError{err: "No existing channels for node_announcement".to_owned(), action: ErrorAction::IgnoreError}),
                        Some(node) => {
                                if let Some(node_info) = node.announcement_info.as_ref() {
                                        if node_info.last_update  >= msg.timestamp {
                                                return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
                                        }
                                }

                                let should_relay = msg.excess_data.is_empty() && msg.excess_address_data.is_empty();
                                node.announcement_info = Some(NodeAnnouncementInfo {
                                        features: msg.features.clone(),
                                        last_update: msg.timestamp,
                                        rgb: msg.rgb,
                                        alias: msg.alias,
                                        addresses: msg.addresses.clone(),
                                        announcement_message: if should_relay { full_msg.cloned() } else { None },
                                });

                                Ok(())
                        }
                }
        }

        /// Store or update channel info from a channel announcement.
        ///
        /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
        /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
        /// routing messages from a source using a protocol other than the lightning P2P protocol.
        ///
        /// If a `chain::Access` object is provided via `chain_access`, it will be called to verify
        /// the corresponding UTXO exists on chain and is correctly-formatted.
        pub fn update_channel_from_announcement<T: secp256k1::Verification, C: Deref>
                        (&mut self, msg: &msgs::ChannelAnnouncement, chain_access: &Option<C>, secp_ctx: &Secp256k1<T>)
                        -> Result<(), LightningError>
                        where C::Target: chain::Access {
                let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
                secp_verify_sig!(secp_ctx, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
                secp_verify_sig!(secp_ctx, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
                secp_verify_sig!(secp_ctx, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
                secp_verify_sig!(secp_ctx, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
                self.update_channel_from_unsigned_announcement_intern(&msg.contents, Some(msg), chain_access)
        }

        /// Store or update channel info from a channel announcement without verifying the associated
        /// signatures. Because we aren't given the associated signatures here we cannot relay the
        /// channel announcement to any of our peers.
        ///
        /// If a `chain::Access` object is provided via `chain_access`, it will be called to verify
        /// the corresponding UTXO exists on chain and is correctly-formatted.
        pub fn update_channel_from_unsigned_announcement<C: Deref>
                        (&mut self, msg: &msgs::UnsignedChannelAnnouncement, chain_access: &Option<C>)
                        -> Result<(), LightningError>
                        where C::Target: chain::Access {
                self.update_channel_from_unsigned_announcement_intern(msg, None, chain_access)
        }

        fn update_channel_from_unsigned_announcement_intern<C: Deref>
                        (&mut self, msg: &msgs::UnsignedChannelAnnouncement, full_msg: Option<&msgs::ChannelAnnouncement>, chain_access: &Option<C>)
                        -> Result<(), LightningError>
                        where C::Target: chain::Access {
                if msg.node_id_1 == msg.node_id_2 || msg.bitcoin_key_1 == msg.bitcoin_key_2 {
                        return Err(LightningError{err: "Channel announcement node had a channel with itself".to_owned(), action: ErrorAction::IgnoreError});
                }

                let utxo_value = match &chain_access {
                        &None => {
                                // Tentatively accept, potentially exposing us to DoS attacks
                                None
                        },
                        &Some(ref chain_access) => {
                                match chain_access.get_utxo(&msg.chain_hash, msg.short_channel_id) {
                                        Ok(TxOut { value, script_pubkey }) => {
                                                let expected_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
                                                                                    .push_slice(&msg.bitcoin_key_1.serialize())
                                                                                    .push_slice(&msg.bitcoin_key_2.serialize())
                                                                                    .push_opcode(opcodes::all::OP_PUSHNUM_2)
                                                                                    .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
                                                if script_pubkey != expected_script {
                                                        return Err(LightningError{err: format!("Channel announcement key ({}) didn't match on-chain script ({})", script_pubkey.to_hex(), expected_script.to_hex()), action: ErrorAction::IgnoreError});
                                                }
                                                //TODO: Check if value is worth storing, use it to inform routing, and compare it
                                                //to the new HTLC max field in channel_update
                                                Some(value)
                                        },
                                        Err(chain::AccessError::UnknownChain) => {
                                                return Err(LightningError{err: format!("Channel announced on an unknown chain ({})", msg.chain_hash.encode().to_hex()), action: ErrorAction::IgnoreError});
                                        },
                                        Err(chain::AccessError::UnknownTx) => {
                                                return Err(LightningError{err: "Channel announced without corresponding UTXO entry".to_owned(), action: ErrorAction::IgnoreError});
                                        },
                                }
                        },
                };

                let chan_info = ChannelInfo {
                                features: msg.features.clone(),
                                node_one: msg.node_id_1.clone(),
                                one_to_two: None,
                                node_two: msg.node_id_2.clone(),
                                two_to_one: None,
                                capacity_sats: utxo_value,
                                announcement_message: if msg.excess_data.is_empty() { full_msg.cloned() } else { None },
                        };

                match self.channels.entry(msg.short_channel_id) {
                        BtreeEntry::Occupied(mut entry) => {
                                //TODO: because asking the blockchain if short_channel_id is valid is only optional
                                //in the blockchain API, we need to handle it smartly here, though it's unclear
                                //exactly how...
                                if utxo_value.is_some() {
                                        // Either our UTXO provider is busted, there was a reorg, or the UTXO provider
                                        // only sometimes returns results. In any case remove the previous entry. Note
                                        // that the spec expects us to "blacklist" the node_ids involved, but we can't
                                        // do that because
                                        // a) we don't *require* a UTXO provider that always returns results.
                                        // b) we don't track UTXOs of channels we know about and remove them if they
                                        //    get reorg'd out.
                                        // c) it's unclear how to do so without exposing ourselves to massive DoS risk.
                                        Self::remove_channel_in_nodes(&mut self.nodes, &entry.get(), msg.short_channel_id);
                                        *entry.get_mut() = chan_info;
                                } else {
                                        return Err(LightningError{err: "Already have knowledge of channel".to_owned(), action: ErrorAction::IgnoreError})
                                }
                        },
                        BtreeEntry::Vacant(entry) => {
                                entry.insert(chan_info);
                        }
                };

                macro_rules! add_channel_to_node {
                        ( $node_id: expr ) => {
                                match self.nodes.entry($node_id) {
                                        BtreeEntry::Occupied(node_entry) => {
                                                node_entry.into_mut().channels.push(msg.short_channel_id);
                                        },
                                        BtreeEntry::Vacant(node_entry) => {
                                                node_entry.insert(NodeInfo {
                                                        channels: vec!(msg.short_channel_id),
                                                        lowest_inbound_channel_fees: None,
                                                        announcement_info: None,
                                                });
                                        }
                                }
                        };
                }

                add_channel_to_node!(msg.node_id_1);
                add_channel_to_node!(msg.node_id_2);

                Ok(())
        }

        /// Close a channel if a corresponding HTLC fail was sent.
        /// If permanent, removes a channel from the local storage.
        /// May cause the removal of nodes too, if this was their last channel.
        /// If not permanent, makes channels unavailable for routing.
        pub fn close_channel_from_update(&mut self, short_channel_id: u64, is_permanent: bool) {
                if is_permanent {
                        if let Some(chan) = self.channels.remove(&short_channel_id) {
                                Self::remove_channel_in_nodes(&mut self.nodes, &chan, short_channel_id);
                        }
                } else {
                        if let Some(chan) = self.channels.get_mut(&short_channel_id) {
                                if let Some(one_to_two) = chan.one_to_two.as_mut() {
                                        one_to_two.enabled = false;
                                }
                                if let Some(two_to_one) = chan.two_to_one.as_mut() {
                                        two_to_one.enabled = false;
                                }
                        }
                }
        }

        fn fail_node(&mut self, _node_id: &PublicKey, is_permanent: bool) {
                if is_permanent {
                        // TODO: Wholly remove the node
                } else {
                        // TODO: downgrade the node
                }
        }

        /// For an already known (from announcement) channel, update info about one of the directions
        /// of the channel.
        ///
        /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
        /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
        /// routing messages from a source using a protocol other than the lightning P2P protocol.
        pub fn update_channel<T: secp256k1::Verification>(&mut self, msg: &msgs::ChannelUpdate, secp_ctx: &Secp256k1<T>) -> Result<(), LightningError> {
                self.update_channel_intern(&msg.contents, Some(&msg), Some((&msg.signature, secp_ctx)))
        }

        /// For an already known (from announcement) channel, update info about one of the directions
        /// of the channel without verifying the associated signatures. Because we aren't given the
        /// associated signatures here we cannot relay the channel update to any of our peers.
        pub fn update_channel_unsigned(&mut self, msg: &msgs::UnsignedChannelUpdate) -> Result<(), LightningError> {
                self.update_channel_intern(msg, None, None::<(&secp256k1::Signature, &Secp256k1<secp256k1::VerifyOnly>)>)
        }

        fn update_channel_intern<T: secp256k1::Verification>(&mut self, msg: &msgs::UnsignedChannelUpdate, full_msg: Option<&msgs::ChannelUpdate>, sig_info: Option<(&secp256k1::Signature, &Secp256k1<T>)>) -> Result<(), LightningError> {
                let dest_node_id;
                let chan_enabled = msg.flags & (1 << 1) != (1 << 1);
                let chan_was_enabled;

                match self.channels.get_mut(&msg.short_channel_id) {
                        None => return Err(LightningError{err: "Couldn't find channel for update".to_owned(), action: ErrorAction::IgnoreError}),
                        Some(channel) => {
                                if let OptionalField::Present(htlc_maximum_msat) = msg.htlc_maximum_msat {
                                        if htlc_maximum_msat > MAX_VALUE_MSAT {
                                                return Err(LightningError{err: "htlc_maximum_msat is larger than maximum possible msats".to_owned(), action: ErrorAction::IgnoreError});
                                        }

                                        if let Some(capacity_sats) = channel.capacity_sats {
                                                // It's possible channel capacity is available now, although it wasn't available at announcement (so the field is None).
                                                // Don't query UTXO set here to reduce DoS risks.
                                                if capacity_sats > MAX_VALUE_MSAT / 1000 || htlc_maximum_msat > capacity_sats * 1000 {
                                                        return Err(LightningError{err: "htlc_maximum_msat is larger than channel capacity or capacity is bogus".to_owned(), action: ErrorAction::IgnoreError});
                                                }
                                        }
                                }
                                macro_rules! maybe_update_channel_info {
                                        ( $target: expr, $src_node: expr) => {
                                                if let Some(existing_chan_info) = $target.as_ref() {
                                                        if existing_chan_info.last_update >= msg.timestamp {
                                                                return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
                                                        }
                                                        chan_was_enabled = existing_chan_info.enabled;
                                                } else {
                                                        chan_was_enabled = false;
                                                }

                                                let last_update_message = if msg.excess_data.is_empty() { full_msg.cloned() } else { None };

                                                let updated_channel_dir_info = DirectionalChannelInfo {
                                                        enabled: chan_enabled,
                                                        last_update: msg.timestamp,
                                                        cltv_expiry_delta: msg.cltv_expiry_delta,
                                                        htlc_minimum_msat: msg.htlc_minimum_msat,
                                                        htlc_maximum_msat: if let OptionalField::Present(max_value) = msg.htlc_maximum_msat { Some(max_value) } else { None },
                                                        fees: RoutingFees {
                                                                base_msat: msg.fee_base_msat,
                                                                proportional_millionths: msg.fee_proportional_millionths,
                                                        },
                                                        last_update_message
                                                };
                                                $target = Some(updated_channel_dir_info);
                                        }
                                }

                                let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
                                if msg.flags & 1 == 1 {
                                        dest_node_id = channel.node_one.clone();
                                        if let Some((sig, ctx)) = sig_info {
                                                secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_two);
                                        }
                                        maybe_update_channel_info!(channel.two_to_one, channel.node_two);
                                } else {
                                        dest_node_id = channel.node_two.clone();
                                        if let Some((sig, ctx)) = sig_info {
                                                secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_one);
                                        }
                                        maybe_update_channel_info!(channel.one_to_two, channel.node_one);
                                }
                        }
                }

                if chan_enabled {
                        let node = self.nodes.get_mut(&dest_node_id).unwrap();
                        let mut base_msat = msg.fee_base_msat;
                        let mut proportional_millionths = msg.fee_proportional_millionths;
                        if let Some(fees) = node.lowest_inbound_channel_fees {
                                base_msat = cmp::min(base_msat, fees.base_msat);
                                proportional_millionths = cmp::min(proportional_millionths, fees.proportional_millionths);
                        }
                        node.lowest_inbound_channel_fees = Some(RoutingFees {
                                base_msat,
                                proportional_millionths
                        });
                } else if chan_was_enabled {
                        let node = self.nodes.get_mut(&dest_node_id).unwrap();
                        let mut lowest_inbound_channel_fees = None;

                        for chan_id in node.channels.iter() {
                                let chan = self.channels.get(chan_id).unwrap();
                                let chan_info_opt;
                                if chan.node_one == dest_node_id {
                                        chan_info_opt = chan.two_to_one.as_ref();
                                } else {
                                        chan_info_opt = chan.one_to_two.as_ref();
                                }
                                if let Some(chan_info) = chan_info_opt {
                                        if chan_info.enabled {
                                                let fees = lowest_inbound_channel_fees.get_or_insert(RoutingFees {
                                                        base_msat: u32::max_value(), proportional_millionths: u32::max_value() });
                                                fees.base_msat = cmp::min(fees.base_msat, chan_info.fees.base_msat);
                                                fees.proportional_millionths = cmp::min(fees.proportional_millionths, chan_info.fees.proportional_millionths);
                                        }
                                }
                        }

                        node.lowest_inbound_channel_fees = lowest_inbound_channel_fees;
                }

                Ok(())
        }

        fn remove_channel_in_nodes(nodes: &mut BTreeMap<PublicKey, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
                macro_rules! remove_from_node {
                        ($node_id: expr) => {
                                if let BtreeEntry::Occupied(mut entry) = nodes.entry($node_id) {
                                        entry.get_mut().channels.retain(|chan_id| {
                                                short_channel_id != *chan_id
                                        });
                                        if entry.get().channels.is_empty() {
                                                entry.remove_entry();
                                        }
                                } else {
                                        panic!("Had channel that pointed to unknown node (ie inconsistent network map)!");
                                }
                        }
                }

                remove_from_node!(chan.node_one);
                remove_from_node!(chan.node_two);
        }
}

#[cfg(test)]
mod tests {
        use chain;
        use ln::features::{ChannelFeatures, NodeFeatures};
        use routing::network_graph::{NetGraphMsgHandler, NetworkGraph};
        use ln::msgs::{OptionalField, RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
                UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate, HTLCFailChannelUpdate,
                ReplyChannelRange, ReplyShortChannelIdsEnd, QueryChannelRange, QueryShortChannelIds, MAX_VALUE_MSAT};
        use util::test_utils;
        use util::logger::Logger;
        use util::ser::{Readable, Writeable};
        use util::events::{MessageSendEvent, MessageSendEventsProvider};

        use bitcoin::hashes::sha256d::Hash as Sha256dHash;
        use bitcoin::hashes::Hash;
        use bitcoin::network::constants::Network;
        use bitcoin::blockdata::constants::genesis_block;
        use bitcoin::blockdata::script::Builder;
        use bitcoin::blockdata::transaction::TxOut;
        use bitcoin::blockdata::opcodes;

        use hex;

        use bitcoin::secp256k1::key::{PublicKey, SecretKey};
        use bitcoin::secp256k1::{All, Secp256k1};

        use std::sync::Arc;

        fn create_net_graph_msg_handler() -> (Secp256k1<All>, NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>) {
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(test_utils::TestLogger::new());
                let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
                let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_hash, None, Arc::clone(&logger));
                (secp_ctx, net_graph_msg_handler)
        }

        #[test]
        fn request_full_sync_finite_times() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap());

                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
                assert!(!net_graph_msg_handler.should_request_full_sync(&node_id));
        }

        #[test]
        fn handling_node_announcements() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();

                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
                let zero_hash = Sha256dHash::hash(&[0; 32]);
                let first_announcement_time = 500;

                let mut unsigned_announcement = UnsignedNodeAnnouncement {
                        features: NodeFeatures::known(),
                        timestamp: first_announcement_time,
                        node_id: node_id_1,
                        rgb: [0; 3],
                        alias: [0; 32],
                        addresses: Vec::new(),
                        excess_address_data: Vec::new(),
                        excess_data: Vec::new(),
                };
                let mut msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = NodeAnnouncement {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_announcement.clone()
                };

                match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!("No existing channels for node_announcement", e.err)
                };

                {
                        // Announce a channel to add a corresponding node.
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::known(),
                                chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                                short_channel_id: 0,
                                node_id_1,
                                node_id_2,
                                bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                                bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                                excess_data: Vec::new(),
                        };

                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_announcement = ChannelAnnouncement {
                                node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                                node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                                bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
                        match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                                Ok(res) => assert!(res),
                                _ => panic!()
                        };
                }

                match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        Err(_) => panic!()
                };

                let fake_msghash = hash_to_message!(&zero_hash);
                match net_graph_msg_handler.handle_node_announcement(
                        &NodeAnnouncement {
                                signature: secp_ctx.sign(&fake_msghash, node_1_privkey),
                                contents: unsigned_announcement.clone()
                }) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Invalid signature from remote node")
                };

                unsigned_announcement.timestamp += 1000;
                unsigned_announcement.excess_data.push(1);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let announcement_with_data = NodeAnnouncement {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_announcement.clone()
                };
                // Return false because contains excess data.
                match net_graph_msg_handler.handle_node_announcement(&announcement_with_data) {
                        Ok(res) => assert!(!res),
                        Err(_) => panic!()
                };
                unsigned_announcement.excess_data = Vec::new();

                // Even though previous announcement was not relayed further, we still accepted it,
                // so we now won't accept announcements before the previous one.
                unsigned_announcement.timestamp -= 10;
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let outdated_announcement = NodeAnnouncement {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_announcement.clone()
                };
                match net_graph_msg_handler.handle_node_announcement(&outdated_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Update older than last processed update")
                };
        }

        #[test]
        fn handling_channel_announcements() {
                let secp_ctx = Secp256k1::new();
                let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());

                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                let good_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
                   .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_1_btckey).serialize())
                   .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_2_btckey).serialize())
                   .push_opcode(opcodes::all::OP_PUSHNUM_2)
                   .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();


                let mut unsigned_announcement = UnsignedChannelAnnouncement {
                        features: ChannelFeatures::known(),
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 0,
                        node_id_1,
                        node_id_2,
                        bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                        bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                        excess_data: Vec::new(),
                };

                let mut msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };

                // Test if the UTXO lookups were not supported
                let mut net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger));
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };

                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&unsigned_announcement.short_channel_id) {
                                None => panic!(),
                                Some(_) => ()
                        }
                }

                // If we receive announcement for the same channel (with UTXO lookups disabled),
                // drop new one on the floor, since we can't see any changes.
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Already have knowledge of channel")
                };

                // Test if an associated transaction were not on-chain (or not confirmed).
                let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
                *chain_source.utxo_ret.lock().unwrap() = Err(chain::AccessError::UnknownTx);
                net_graph_msg_handler = NetGraphMsgHandler::new(chain_source.clone().genesis_hash, Some(chain_source.clone()), Arc::clone(&logger));
                unsigned_announcement.short_channel_id += 1;

                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };

                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Channel announced without corresponding UTXO entry")
                };

                // Now test if the transaction is found in the UTXO set and the script is correct.
                unsigned_announcement.short_channel_id += 1;
                *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script.clone() });

                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };

                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&unsigned_announcement.short_channel_id) {
                                None => panic!(),
                                Some(_) => ()
                        }
                }

                // If we receive announcement for the same channel (but TX is not confirmed),
                // drop new one on the floor, since we can't see any changes.
                *chain_source.utxo_ret.lock().unwrap() = Err(chain::AccessError::UnknownTx);
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Channel announced without corresponding UTXO entry")
                };

                // But if it is confirmed, replace the channel
                *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script });
                unsigned_announcement.features = ChannelFeatures::empty();
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };
                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&unsigned_announcement.short_channel_id) {
                                Some(channel_entry) => {
                                        assert_eq!(channel_entry.features, ChannelFeatures::empty());
                                },
                                _ => panic!()
                        }
                }

                // Don't relay valid channels with excess data
                unsigned_announcement.short_channel_id += 1;
                unsigned_announcement.excess_data.push(1);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(!res),
                        _ => panic!()
                };

                unsigned_announcement.excess_data = Vec::new();
                let invalid_sig_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_1_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&invalid_sig_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Invalid signature from remote node")
                };

                unsigned_announcement.node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let channel_to_itself_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_2_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&channel_to_itself_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Channel announcement node had a channel with itself")
                };
        }

        #[test]
        fn handling_channel_update() {
                let secp_ctx = Secp256k1::new();
                let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());
                let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
                let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), Some(chain_source.clone()), Arc::clone(&logger));

                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                let zero_hash = Sha256dHash::hash(&[0; 32]);
                let short_channel_id = 0;
                let chain_hash = genesis_block(Network::Testnet).header.block_hash();
                let amount_sats = 1000_000;

                {
                        // Announce a channel we will update
                        let good_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
                           .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_1_btckey).serialize())
                           .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_2_btckey).serialize())
                           .push_opcode(opcodes::all::OP_PUSHNUM_2)
                           .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
                        *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: amount_sats, script_pubkey: good_script.clone() });
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::empty(),
                                chain_hash,
                                short_channel_id,
                                node_id_1,
                                node_id_2,
                                bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                                bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                                excess_data: Vec::new(),
                        };

                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_channel_announcement = ChannelAnnouncement {
                                node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                                node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                                bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
                        match net_graph_msg_handler.handle_channel_announcement(&valid_channel_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };

                }

                let mut unsigned_channel_update = UnsignedChannelUpdate {
                        chain_hash,
                        short_channel_id,
                        timestamp: 100,
                        flags: 0,
                        cltv_expiry_delta: 144,
                        htlc_minimum_msat: 1000000,
                        htlc_maximum_msat: OptionalField::Absent,
                        fee_base_msat: 10000,
                        fee_proportional_millionths: 20,
                        excess_data: Vec::new()
                };
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };

                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
                                        assert_eq!(channel_info.one_to_two.as_ref().unwrap().cltv_expiry_delta, 144);
                                        assert!(channel_info.two_to_one.is_none());
                                }
                        }
                }

                unsigned_channel_update.timestamp += 100;
                unsigned_channel_update.excess_data.push(1);
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };
                // Return false because contains excess data
                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(res) => assert!(!res),
                        _ => panic!()
                };
                unsigned_channel_update.timestamp += 10;

                unsigned_channel_update.short_channel_id += 1;
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Couldn't find channel for update")
                };
                unsigned_channel_update.short_channel_id = short_channel_id;

                unsigned_channel_update.htlc_maximum_msat = OptionalField::Present(MAX_VALUE_MSAT + 1);
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "htlc_maximum_msat is larger than maximum possible msats")
                };
                unsigned_channel_update.htlc_maximum_msat = OptionalField::Absent;

                unsigned_channel_update.htlc_maximum_msat = OptionalField::Present(amount_sats * 1000 + 1);
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "htlc_maximum_msat is larger than channel capacity or capacity is bogus")
                };
                unsigned_channel_update.htlc_maximum_msat = OptionalField::Absent;

                // Even though previous update was not relayed further, we still accepted it,
                // so we now won't accept update before the previous one.
                unsigned_channel_update.timestamp -= 10;
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Update older than last processed update")
                };
                unsigned_channel_update.timestamp += 500;

                let fake_msghash = hash_to_message!(&zero_hash);
                let invalid_sig_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&fake_msghash, node_1_privkey),
                        contents: unsigned_channel_update.clone()
                };

                match net_graph_msg_handler.handle_channel_update(&invalid_sig_channel_update) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Invalid signature from remote node")
                };

        }

        #[test]
        fn handling_htlc_fail_channel_update() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                let short_channel_id = 0;
                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                {
                        // There is no nodes in the table at the beginning.
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        assert_eq!(network.get_nodes().len(), 0);
                }

                {
                        // Announce a channel we will update
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::empty(),
                                chain_hash,
                                short_channel_id,
                                node_id_1,
                                node_id_2,
                                bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                                bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                                excess_data: Vec::new(),
                        };

                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_channel_announcement = ChannelAnnouncement {
                                node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                                node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                                bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
                        match net_graph_msg_handler.handle_channel_announcement(&valid_channel_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };

                        let unsigned_channel_update = UnsignedChannelUpdate {
                                chain_hash,
                                short_channel_id,
                                timestamp: 100,
                                flags: 0,
                                cltv_expiry_delta: 144,
                                htlc_minimum_msat: 1000000,
                                htlc_maximum_msat: OptionalField::Absent,
                                fee_base_msat: 10000,
                                fee_proportional_millionths: 20,
                                excess_data: Vec::new()
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                        let valid_channel_update = ChannelUpdate {
                                signature: secp_ctx.sign(&msghash, node_1_privkey),
                                contents: unsigned_channel_update.clone()
                        };

                        match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                                Ok(res) => assert!(res),
                                _ => panic!()
                        };
                }

                // Non-permanent closing just disables a channel
                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
                                        assert!(channel_info.one_to_two.is_some());
                                }
                        }
                }

                let channel_close_msg = HTLCFailChannelUpdate::ChannelClosed {
                        short_channel_id,
                        is_permanent: false
                };

                net_graph_msg_handler.handle_htlc_fail_channel_update(&channel_close_msg);

                // Non-permanent closing just disables a channel
                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        match network.get_channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
                                        assert!(!channel_info.one_to_two.as_ref().unwrap().enabled);
                                }
                        }
                }

                let channel_close_msg = HTLCFailChannelUpdate::ChannelClosed {
                        short_channel_id,
                        is_permanent: true
                };

                net_graph_msg_handler.handle_htlc_fail_channel_update(&channel_close_msg);

                // Permanent closing deletes a channel
                {
                        let network = net_graph_msg_handler.network_graph.read().unwrap();
                        assert_eq!(network.get_channels().len(), 0);
                        // Nodes are also deleted because there are no associated channels anymore
                        assert_eq!(network.get_nodes().len(), 0);
                }
                // TODO: Test HTLCFailChannelUpdate::NodeFailure, which is not implemented yet.
        }

        #[test]
        fn getting_next_channel_announcements() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                let short_channel_id = 1;
                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                // Channels were not announced yet.
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(0, 1);
                assert_eq!(channels_with_announcements.len(), 0);

                {
                        // Announce a channel we will update
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::empty(),
                                chain_hash,
                                short_channel_id,
                                node_id_1,
                                node_id_2,
                                bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                                bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                                excess_data: Vec::new(),
                        };

                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_channel_announcement = ChannelAnnouncement {
                                node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                                node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                                bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
                        match net_graph_msg_handler.handle_channel_announcement(&valid_channel_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };
                }

                // Contains initial channel announcement now.
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(short_channel_id, 1);
                assert_eq!(channels_with_announcements.len(), 1);
                if let Some(channel_announcements) = channels_with_announcements.first() {
                        let &(_, ref update_1, ref update_2) = channel_announcements;
                        assert_eq!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
                        panic!();
                }


                {
                        // Valid channel update
                        let unsigned_channel_update = UnsignedChannelUpdate {
                                chain_hash,
                                short_channel_id,
                                timestamp: 101,
                                flags: 0,
                                cltv_expiry_delta: 144,
                                htlc_minimum_msat: 1000000,
                                htlc_maximum_msat: OptionalField::Absent,
                                fee_base_msat: 10000,
                                fee_proportional_millionths: 20,
                                excess_data: Vec::new()
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                        let valid_channel_update = ChannelUpdate {
                                signature: secp_ctx.sign(&msghash, node_1_privkey),
                                contents: unsigned_channel_update.clone()
                        };
                        match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };
                }

                // Now contains an initial announcement and an update.
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(short_channel_id, 1);
                assert_eq!(channels_with_announcements.len(), 1);
                if let Some(channel_announcements) = channels_with_announcements.first() {
                        let &(_, ref update_1, ref update_2) = channel_announcements;
                        assert_ne!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
                        panic!();
                }


                {
                        // Channel update with excess data.
                        let unsigned_channel_update = UnsignedChannelUpdate {
                                chain_hash,
                                short_channel_id,
                                timestamp: 102,
                                flags: 0,
                                cltv_expiry_delta: 144,
                                htlc_minimum_msat: 1000000,
                                htlc_maximum_msat: OptionalField::Absent,
                                fee_base_msat: 10000,
                                fee_proportional_millionths: 20,
                                excess_data: [1; 3].to_vec()
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                        let valid_channel_update = ChannelUpdate {
                                signature: secp_ctx.sign(&msghash, node_1_privkey),
                                contents: unsigned_channel_update.clone()
                        };
                        match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };
                }

                // Test that announcements with excess data won't be returned
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(short_channel_id, 1);
                assert_eq!(channels_with_announcements.len(), 1);
                if let Some(channel_announcements) = channels_with_announcements.first() {
                        let &(_, ref update_1, ref update_2) = channel_announcements;
                        assert_eq!(update_1, &None);
                        assert_eq!(update_2, &None);
                } else {
                        panic!();
                }

                // Further starting point have no channels after it
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(short_channel_id + 1000, 1);
                assert_eq!(channels_with_announcements.len(), 0);
        }

        #[test]
        fn getting_next_node_announcements() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                let short_channel_id = 1;
                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                // No nodes yet.
                let next_announcements = net_graph_msg_handler.get_next_node_announcements(None, 10);
                assert_eq!(next_announcements.len(), 0);

                {
                        // Announce a channel to add 2 nodes
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::empty(),
                                chain_hash,
                                short_channel_id,
                                node_id_1,
                                node_id_2,
                                bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                                bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                                excess_data: Vec::new(),
                        };

                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_channel_announcement = ChannelAnnouncement {
                                node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                                node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                                bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
                        match net_graph_msg_handler.handle_channel_announcement(&valid_channel_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };
                }


                // Nodes were never announced
                let next_announcements = net_graph_msg_handler.get_next_node_announcements(None, 3);
                assert_eq!(next_announcements.len(), 0);

                {
                        let mut unsigned_announcement = UnsignedNodeAnnouncement {
                                features: NodeFeatures::known(),
                                timestamp: 1000,
                                node_id: node_id_1,
                                rgb: [0; 3],
                                alias: [0; 32],
                                addresses: Vec::new(),
                                excess_address_data: Vec::new(),
                                excess_data: Vec::new(),
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_announcement = NodeAnnouncement {
                                signature: secp_ctx.sign(&msghash, node_1_privkey),
                                contents: unsigned_announcement.clone()
                        };
                        match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };

                        unsigned_announcement.node_id = node_id_2;
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_announcement = NodeAnnouncement {
                                signature: secp_ctx.sign(&msghash, node_2_privkey),
                                contents: unsigned_announcement.clone()
                        };

                        match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                                Ok(_) => (),
                                Err(_) => panic!()
                        };
                }

                let next_announcements = net_graph_msg_handler.get_next_node_announcements(None, 3);
                assert_eq!(next_announcements.len(), 2);

                // Skip the first node.
                let next_announcements = net_graph_msg_handler.get_next_node_announcements(Some(&node_id_1), 2);
                assert_eq!(next_announcements.len(), 1);

                {
                        // Later announcement which should not be relayed (excess data) prevent us from sharing a node
                        let unsigned_announcement = UnsignedNodeAnnouncement {
                                features: NodeFeatures::known(),
                                timestamp: 1010,
                                node_id: node_id_2,
                                rgb: [0; 3],
                                alias: [0; 32],
                                addresses: Vec::new(),
                                excess_address_data: Vec::new(),
                                excess_data: [1; 3].to_vec(),
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_announcement = NodeAnnouncement {
                                signature: secp_ctx.sign(&msghash, node_2_privkey),
                                contents: unsigned_announcement.clone()
                        };
                        match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                                Ok(res) => assert!(!res),
                                Err(_) => panic!()
                        };
                }

                let next_announcements = net_graph_msg_handler.get_next_node_announcements(Some(&node_id_1), 2);
                assert_eq!(next_announcements.len(), 0);
        }

        #[test]
        fn network_graph_serialization() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();

                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();

                // Announce a channel to add a corresponding node.
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let unsigned_announcement = UnsignedChannelAnnouncement {
                        features: ChannelFeatures::known(),
                        chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 0,
                        node_id_1,
                        node_id_2,
                        bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, node_1_btckey),
                        bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, node_2_btckey),
                        excess_data: Vec::new(),
                };

                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
                        node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
                };
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };


                let node_id = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
                let unsigned_announcement = UnsignedNodeAnnouncement {
                        features: NodeFeatures::known(),
                        timestamp: 100,
                        node_id,
                        rgb: [0; 3],
                        alias: [0; 32],
                        addresses: Vec::new(),
                        excess_address_data: Vec::new(),
                        excess_data: Vec::new(),
                };
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = NodeAnnouncement {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
                        contents: unsigned_announcement.clone()
                };

                match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
                        Ok(_) => (),
                        Err(_) => panic!()
                };

                let network = net_graph_msg_handler.network_graph.write().unwrap();
                let mut w = test_utils::TestVecWriter(Vec::new());
                assert!(!network.get_nodes().is_empty());
                assert!(!network.get_channels().is_empty());
                network.write(&mut w).unwrap();
                assert!(<NetworkGraph>::read(&mut ::std::io::Cursor::new(&w.0)).unwrap() == *network);
        }

        #[test]
        fn sending_query_channel_range() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_privkey_2 = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_privkey_2);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();
                let first_blocknum = 0;
                let number_of_blocks = 0xffff_ffff;

                // When no active query exists for the node, it should send a query message and generate a task
                {
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, first_blocknum, number_of_blocks);
                        assert!(result.is_ok());

                        // It should create a task for the query
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().contains_key(&node_id_1));

                        // It should send a query_channel_range message with the correct information
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendChannelRangeQuery{ node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.first_blocknum, first_blocknum);
                                        assert_eq!(msg.number_of_blocks, number_of_blocks);
                                },
                                _ => panic!("Expected MessageSendEvent::SendChannelRangeQuery")
                        };
                }

                // When an active query exists for the node, when there is a subsequent query request, it
                // should fail to initiate a new query
                {
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, first_blocknum, number_of_blocks);
                        assert_eq!(result.is_err(), true);
                }

                // When no active query exists for a different node, it should send a query message
                {
                        let result = net_graph_msg_handler.query_channel_range(&node_id_2, chain_hash, first_blocknum, number_of_blocks);
                        assert_eq!(result.is_ok(), true);

                        // It should create a task for the query
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().contains_key(&node_id_2));

                        // It should send a query_channel_message with the correct information
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendChannelRangeQuery{ node_id, msg } => {
                                        assert_eq!(node_id, &node_id_2);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.first_blocknum, first_blocknum);
                                        assert_eq!(msg.number_of_blocks, number_of_blocks);
                                },
                                _ => panic!("Expected MessageSendEvent::SendChannelRangeQuery")
                        };
                }
        }

        #[test]
        fn sending_query_short_channel_ids() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                // The first query should send the batch of scids to the peer
                {
                        let short_channel_ids: Vec<u64> = vec![0, 1, 2];
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id_1, chain_hash, short_channel_ids.clone());
                        assert!(result.is_ok());

                        // Validate that we have enqueued a send message event and that it contains the correct information
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery{ node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, short_channel_ids);
                                },
                                _ => panic!("Expected MessageSendEvent::SendShortIdsQuery")
                        };
                }

                // Subsequent queries for scids should enqueue them to be sent in the next batch which will
                // be sent when a reply_short_channel_ids_end message is handled.
                {
                        let short_channel_ids: Vec<u64> = vec![3, 4, 5];
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id_1, chain_hash, short_channel_ids.clone());
                        assert!(result.is_ok());

                        // Validate that we have not enqueued another send message event yet
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 0);

                        // Validate the task has the queued scids
                        assert_eq!(
                                net_graph_msg_handler.scid_query_tasks.lock().unwrap().get(&node_id_1).unwrap().short_channel_ids,
                                short_channel_ids
                        );
                }
        }

        #[test]
        fn handling_reply_channel_range() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                // Test receipt of an unknown reply message. We expect an error
                {
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 1050,
                                short_channel_ids: vec![
                                        0x0003e8_000000_0000, // 1000x0x0
                                        0x0003e9_000000_0000, // 1001x0x0
                                        0x0003f0_000000_0000  // 1008x0x0
                                ],
                        });
                        assert!(result.is_err());
                }

                // Test receipt of a single reply_channel_range that exactly matches the queried range.
                // It sends a query_short_channel_ids with the returned scids and removes the pending task
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle a single successful reply that matches the queried channel range
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 100,
                                short_channel_ids: vec![
                                        0x0003e8_000000_0000, // 1000x0x0
                                        0x0003e9_000000_0000, // 1001x0x0
                                        0x0003f0_000000_0000  // 1008x0x0
                                ],
                        });
                        assert!(result.is_ok());

                        // The query is now complete, so we expect the task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());

                        // We expect to emit a query_short_channel_ids message with scids in our query range
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, vec![0x0003e8_000000_0000,0x0003e9_000000_0000,0x0003f0_000000_0000]);
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // Clean up scid_task
                        net_graph_msg_handler.scid_query_tasks.lock().unwrap().clear();
                }

                // Test receipt of a single reply_channel_range for a query that has a u32 overflow. We expect
                // it sends a query_short_channel_ids with the returned scids and removes the pending task.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 0xffff_ffff);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle a single successful reply that matches the queried channel range
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 0xffff_ffff,
                                short_channel_ids: vec![
                                        0x0003e8_000000_0000, // 1000x0x0
                                        0x0003e9_000000_0000, // 1001x0x0
                                        0x0003f0_000000_0000  // 1008x0x0
                                ],
                        });
                        assert!(result.is_ok());

                        // The query is now complete, so we expect the task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());

                        // We expect to emit a query_short_channel_ids message with scids in our query range
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, vec![0x0003e8_000000_0000,0x0003e9_000000_0000,0x0003f0_000000_0000]);
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // Clean up scid_task
                        net_graph_msg_handler.scid_query_tasks.lock().unwrap().clear();
                }

                // Test receipt of a single reply that encompasses the queried channel range. This is allowed
                // since a reply must contain at least part of the query range. Receipt of the reply should
                // send a query_short_channel_ids message with scids filtered to the query range and remove
                // the pending task.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle a single successful reply that encompasses the queried channel range
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 0,
                                number_of_blocks: 2000,
                                short_channel_ids: vec![
                                        0x0003e0_000000_0000, // 992x0x0
                                        0x0003e8_000000_0000, // 1000x0x0
                                        0x0003e9_000000_0000, // 1001x0x0
                                        0x0003f0_000000_0000, // 1008x0x0
                                        0x00044c_000000_0000, // 1100x0x0
                                        0x0006e0_000000_0000, // 1760x0x0
                                ],
                        });
                        assert!(result.is_ok());

                        // The query is now complete, so we expect the task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());

                        // We expect to emit a query_short_channel_ids message with scids filtered to those
                        // within the original query range.
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, vec![0x0003e8_000000_0000,0x0003e9_000000_0000,0x0003f0_000000_0000]);
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // Clean up scid_task
                        net_graph_msg_handler.scid_query_tasks.lock().unwrap().clear();
                }

                // Test receipt of multiple reply messages for a single query. This happens when the number
                // of scids in the query range exceeds the size limits of a single reply message. We expect
                // to initiate a query_short_channel_ids for the first batch of scids and we enqueue the
                // remaining scids for later processing. We remove the range query task after receipt of all
                // reply messages.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the first reply message
                        let reply_1_scids =  vec![
                                0x0003e8_000000_0000, // 1000x0x0
                                0x0003e9_000000_0000, // 1001x0x0
                                0x000419_000000_0000, // 1049x0x0
                        ];
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 50,
                                short_channel_ids: reply_1_scids.clone(),
                        });
                        assert!(result.is_ok());

                        // Handle the next reply in the sequence, which must start at the previous message's
                        // first_blocknum plus number_of_blocks. The scids in this reply will be queued.
                        let reply_2_scids = vec![
                                0x00041a_000000_0000, // 1050x0x0
                                0x000432_000000_0000, // 1074x0x0
                        ];
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1050,
                                number_of_blocks: 25,
                                short_channel_ids: reply_2_scids.clone(),
                        });
                        assert!(result.is_ok());

                        // Handle the final reply in the sequence, which must meet or exceed the initial query's
                        // first_blocknum plus number_of_blocks. The scids in this reply will be queued.
                        let reply_3_scids = vec![
                                0x000433_000000_0000, // 1075x0x0
                                0x00044b_000000_0000, // 1099x0x0
                        ];
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1075,
                                number_of_blocks: 25,
                                short_channel_ids: reply_3_scids.clone(),
                        });
                        assert!(result.is_ok());

                        // After the final reply we expect the query task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());

                        // We expect to emit a query_short_channel_ids message with the accumulated scids that
                        // match the queried channel range.
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, [reply_1_scids, reply_2_scids, reply_3_scids].concat());
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // Clean up scid_task
                        net_graph_msg_handler.scid_query_tasks.lock().unwrap().clear();
                }

                // Test receipt of a sequence of replies with a valid first reply and a second reply that
                // resumes on the same block as the first reply. The spec requires a subsequent
                // first_blocknum to equal the prior first_blocknum plus number_of_blocks, however
                // due to discrepancies in implementation we must loosen this restriction.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the first reply message
                        let reply_1_scids = vec![
                                0x0003e8_000000_0000, // 1000x0x0
                                0x0003e9_000000_0000, // 1001x0x0
                                0x000419_000000_0000, // 1049x0x0
                        ];
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 50,
                                short_channel_ids: reply_1_scids.clone(),
                        });
                        assert!(result.is_ok());

                        // Handle the next reply in the sequence, which is non-spec but resumes on the last block
                        // of the first message.
                        let reply_2_scids = vec![
                                0x000419_000001_0000, // 1049x1x0
                                0x00041a_000000_0000, // 1050x0x0
                                0x000432_000000_0000, // 1074x0x0
                        ];
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1049,
                                number_of_blocks: 51,
                                short_channel_ids: reply_2_scids.clone(),
                        });
                        assert!(result.is_ok());

                        // After the final reply we expect the query task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());

                        // We expect to emit a query_short_channel_ids message with the accumulated scids that
                        // match the queried channel range
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, &node_id_1);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, [reply_1_scids, reply_2_scids].concat());
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // Clean up scid_task
                        net_graph_msg_handler.scid_query_tasks.lock().unwrap().clear();
                }

                // Test receipt of reply with a chain_hash that does not match the query. We expect to return
                // an error and to remove the query task.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the reply with a mismatched chain_hash. We expect IgnoreError result and the
                        // task should be removed.
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash: genesis_block(Network::Bitcoin).header.block_hash(),
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 1050,
                                short_channel_ids: vec![0x0003e8_000000_0000,0x0003e9_000000_0000,0x0003f0_000000_0000],
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Received reply_channel_range with invalid chain_hash");
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a reply that indicates the remote node does not maintain up-to-date
                // information for the chain_hash. Because of discrepancies in implementation we use
                // full_information=false and short_channel_ids=[] as the signal. We should expect an error
                // and the task should be removed.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the reply indicating the peer was unable to fulfill our request.
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: false,
                                first_blocknum: 1000,
                                number_of_blocks: 100,
                                short_channel_ids: vec![],
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Received reply_channel_range with no information available");
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a reply that has a first_blocknum that is above the first_blocknum
                // requested in our query. The reply must contain the queried block range. We expect an
                // error result and the task should be removed.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the reply that has a first_blocknum above the query's first_blocknum
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1001,
                                number_of_blocks: 100,
                                short_channel_ids: vec![],
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Failing reply_channel_range with invalid first_blocknum");
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a first reply that does not overlap the query range at all. The first message
                // must have some overlap with the query. We expect an error result and the task should
                // be removed.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle a reply that contains a block range that precedes the queried block range
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 0,
                                number_of_blocks: 1000,
                                short_channel_ids: vec![],
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Failing reply_channel_range with non-overlapping first reply");
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a sequence of replies with a valid first reply and a second reply that is
                // non-sequential. The spec requires a subsequent first_blocknum to equal the prior
                // first_blocknum plus number_of_blocks. We expect an IgnoreError result and the task should
                // be removed.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 100);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the first reply
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1000,
                                number_of_blocks: 50,
                                short_channel_ids: vec![0x0003e8_000000_0000,0x0003e9_000000_0000,0x0003f0_000000_0000],
                        });
                        assert!(result.is_ok());

                        // Handle the second reply which does not start at the proper first_blocknum. We expect
                        // to return an error and remove the task.
                        let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                chain_hash,
                                full_information: true,
                                first_blocknum: 1051,
                                number_of_blocks: 50,
                                short_channel_ids: vec![0x0003f1_000000_0000,0x0003f2_000000_0000],
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Failing reply_channel_range with invalid sequence");
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of too many reply messages. We expect an IgnoreError result and the task should
                // be removed.
                {
                        // Initiate a channel range query to create a query task
                        let result = net_graph_msg_handler.query_channel_range(&node_id_1, chain_hash, 1000, 0xffff_ffff);
                        assert!(result.is_ok());

                        // Clear the SendRangeQuery event
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle a sequence of replies that will fail once the max number of reply has been exceeded.
                        for block in 1000..=1000 + super::MAX_REPLY_CHANNEL_RANGE_PER_QUERY + 10 {
                                let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, &ReplyChannelRange {
                                        chain_hash,
                                        full_information: true,
                                        first_blocknum: block as u32,
                                        number_of_blocks: 1,
                                        short_channel_ids: vec![(block as u64) << 40],
                                });
                                if block <= 1000 + super::MAX_REPLY_CHANNEL_RANGE_PER_QUERY {
                                        assert!(result.is_ok());
                                } else if block == 1001 + super::MAX_REPLY_CHANNEL_RANGE_PER_QUERY {
                                        assert!(result.is_err());
                                        assert_eq!(result.err().unwrap().err, "Failing reply_channel_range due to excessive messages");
                                } else {
                                        assert!(result.is_err());
                                        assert_eq!(result.err().unwrap().err, "Received unknown reply_channel_range message");
                                }
                        }

                        // Expect the task to be removed
                        assert!(net_graph_msg_handler.chan_range_query_tasks.lock().unwrap().is_empty());
                }
        }

        #[test]
        fn handling_reply_short_channel_ids() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                // Test receipt of a reply when no query exists. We expect an error to be returned
                {
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash,
                                full_information: true,
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Unknown reply_short_channel_ids_end message");
                }

                // Test receipt of a reply that is for a different chain_hash. We expect an error and the task
                // should be removed.
                {
                        // Initiate a query to create a pending query task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003e8_000000_0000]);
                        assert!(result.is_ok());

                        // Process reply with incorrect chain_hash
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash: genesis_block(Network::Bitcoin).header.block_hash(),
                                full_information: true,
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Received reply_short_channel_ids_end with incorrect chain_hash");

                        // Expect the task to be removed
                        assert!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a reply that indicates the peer does not maintain up-to-date information
                // for the chain_hash requested in the query. We expect an error and task should be removed.
                {
                        // Initiate a query to create a pending query task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003e8_000000_0000]);
                        assert!(result.is_ok());

                        // Process failed reply
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash,
                                full_information: false,
                        });
                        assert!(result.is_err());
                        assert_eq!(result.err().unwrap().err, "Received reply_short_channel_ids_end with no information");

                        // Expect the task to be removed
                        assert!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a successful reply when there are no additional scids to query. We expect
                // the task to be removed.
                {
                        // Initiate a query to create a pending query task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003e8_000000_0000]);
                        assert!(result.is_ok());

                        // Process success reply
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash,
                                full_information: true,
                        });
                        assert!(result.is_ok());

                        // Expect the task to be removed
                        assert!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().is_empty());
                }

                // Test receipt of a successful reply when there are additional scids to query. We expect
                // additional queries to be sent until the task can be removed.
                {
                        // Initiate a query to create a pending query task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003e8_000000_0000]);
                        assert!(result.is_ok());

                        // Initiate a second query to add pending scids to the task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003e9_000000_0000]);
                        assert!(result.is_ok());
                        assert_eq!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().get(&node_id).unwrap().short_channel_ids, vec![0x0003e9_000000_0000]);

                        // Initiate a third query to add pending scids to the task
                        let result = net_graph_msg_handler.query_short_channel_ids(&node_id, chain_hash, vec![0x0003f0_000000_0000]);
                        assert!(result.is_ok());
                        assert_eq!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().get(&node_id).unwrap().short_channel_ids, vec![0x0003e9_000000_0000, 0x0003f0_000000_0000]);

                        // Clear all of the pending send events
                        net_graph_msg_handler.get_and_clear_pending_msg_events();

                        // Handle the first successful reply, which will send the next batch of scids in a new query
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash,
                                full_information: true,
                        });
                        assert!(result.is_ok());

                        // We expect the second batch to be sent in an event
                        let expected_node_id = &node_id;
                        let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
                        assert_eq!(events.len(), 1);
                        match &events[0] {
                                MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
                                        assert_eq!(node_id, expected_node_id);
                                        assert_eq!(msg.chain_hash, chain_hash);
                                        assert_eq!(msg.short_channel_ids, vec![0x0003e9_000000_0000, 0x0003f0_000000_0000]);
                                },
                                _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
                        }

                        // We expect the scids to be cleared from the task
                        assert_eq!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().get(&node_id).unwrap().short_channel_ids.len(), 0);

                        // Handle the second successful reply
                        let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, &ReplyShortChannelIdsEnd {
                                chain_hash,
                                full_information: true,
                        });
                        assert!(result.is_ok());

                        // We expect the task should be removed
                        assert!(net_graph_msg_handler.scid_query_tasks.lock().unwrap().is_empty());
                }
        }

        #[test]
        fn handling_query_channel_range() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                let result = net_graph_msg_handler.handle_query_channel_range(&node_id, &QueryChannelRange {
                        chain_hash,
                        first_blocknum: 0,
                        number_of_blocks: 0xffff_ffff,
                });
                assert!(result.is_err());
        }

        #[test]
        fn handling_query_short_channel_ids() {
                let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
                let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);

                let chain_hash = genesis_block(Network::Testnet).header.block_hash();

                let result = net_graph_msg_handler.handle_query_short_channel_ids(&node_id, &QueryShortChannelIds {
                        chain_hash,
                        short_channel_ids: vec![0x0003e8_000000_0000],
                });
                assert!(result.is_err());
        }
}