Fix re-sending commitment updates with an outbound fee update
[rust-lightning] / lightning / src / ln / channel.rs
index f46d76042df91601e4bc278425906e40bf075e37..4795a2524baff9dfc6e26d4481eb90d5d9d71740 100644 (file)
@@ -9,15 +9,15 @@
 
 use bitcoin::blockdata::script::{Script,Builder};
 use bitcoin::blockdata::transaction::{TxIn, TxOut, Transaction, SigHashType};
-use bitcoin::blockdata::opcodes;
 use bitcoin::util::bip143;
 use bitcoin::consensus::encode;
 
 use bitcoin::hashes::Hash;
 use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::sha256d::Hash as Sha256d;
-use bitcoin::hash_types::{Txid, BlockHash, WPubkeyHash};
+use bitcoin::hash_types::{Txid, BlockHash};
 
+use bitcoin::secp256k1::constants::PUBLIC_KEY_SIZE;
 use bitcoin::secp256k1::key::{PublicKey,SecretKey};
 use bitcoin::secp256k1::{Secp256k1,Signature};
 use bitcoin::secp256k1;
@@ -26,6 +26,7 @@ use ln::{PaymentPreimage, PaymentHash};
 use ln::features::{ChannelFeatures, InitFeatures};
 use ln::msgs;
 use ln::msgs::{DecodeError, OptionalField, DataLossProtect};
+use ln::script::ShutdownScript;
 use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT};
 use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor};
 use ln::chan_utils;
@@ -41,13 +42,14 @@ use util::errors::APIError;
 use util::config::{UserConfig,ChannelConfig};
 use util::scid_utils::scid_from_parts;
 
+use io;
 use prelude::*;
 use core::{cmp,mem,fmt};
+use core::convert::TryFrom;
 use core::ops::Deref;
-#[cfg(any(test, feature = "fuzztarget"))]
-use std::sync::Mutex;
+#[cfg(any(test, feature = "fuzztarget", debug_assertions))]
+use sync::Mutex;
 use bitcoin::hashes::hex::ToHex;
-use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0;
 
 #[cfg(test)]
 pub struct ChannelValueStat {
@@ -273,6 +275,14 @@ enum HTLCInitiator {
        RemoteOffered,
 }
 
+/// An enum gathering stats on pending HTLCs, either inbound or outbound side.
+struct HTLCStats {
+       pending_htlcs: u32,
+       pending_htlcs_value_msat: u64,
+       on_counterparty_tx_dust_exposure_msat: u64,
+       on_holder_tx_dust_exposure_msat: u64,
+}
+
 /// Used when calculating whether we or the remote can afford an additional HTLC.
 struct HTLCCandidate {
        amount_msat: u64,
@@ -306,6 +316,7 @@ pub struct CounterpartyForwardingInfo {
 enum UpdateFulfillFetch {
        NewClaim {
                monitor_update: ChannelMonitorUpdate,
+               htlc_value_msat: u64,
                msg: Option<msgs::UpdateFulfillHTLC>,
        },
        DuplicateClaim {},
@@ -319,6 +330,8 @@ pub enum UpdateFulfillCommitFetch {
        NewClaim {
                /// The ChannelMonitorUpdate which places the new payment preimage in the channel monitor
                monitor_update: ChannelMonitorUpdate,
+               /// The value of the HTLC which was claimed, in msat.
+               htlc_value_msat: u64,
                /// The update_fulfill message and commitment_signed message (if the claim was not placed
                /// in the holding cell).
                msgs: Option<(msgs::UpdateFulfillHTLC, msgs::CommitmentSigned)>,
@@ -328,6 +341,22 @@ pub enum UpdateFulfillCommitFetch {
        DuplicateClaim {},
 }
 
+/// If the majority of the channels funds are to the fundee and the initiator holds only just
+/// enough funds to cover their reserve value, channels are at risk of getting "stuck". Because the
+/// initiator controls the feerate, if they then go to increase the channel fee, they may have no
+/// balance but the fundee is unable to send a payment as the increase in fee more than drains
+/// their reserve value. Thus, neither side can send a new HTLC and the channel becomes useless.
+/// Thus, before sending an HTLC when we are the initiator, we check that the feerate can increase
+/// by this multiple without hitting this case, before sending.
+/// This multiple is effectively the maximum feerate "jump" we expect until more HTLCs flow over
+/// the channel. Sadly, there isn't really a good number for this - if we expect to have no new
+/// HTLCs for days we may need this to suffice for feerate increases across days, but that may
+/// leave the channel less usable as we hold a bigger reserve.
+#[cfg(fuzzing)]
+pub const FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE: u64 = 2;
+#[cfg(not(fuzzing))]
+const FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE: u64 = 2;
+
 // TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking
 // has been completed, and then turn into a Channel to get compiler-time enforcement of things like
 // calling channel_id() before we're set up or things like get_outbound_funding_signed on an
@@ -336,6 +365,9 @@ pub enum UpdateFulfillCommitFetch {
 // Holder designates channel data owned for the benefice of the user client.
 // Counterparty designates channel data owned by the another channel participant entity.
 pub(super) struct Channel<Signer: Sign> {
+       #[cfg(any(test, feature = "_test_utils"))]
+       pub(crate) config: ChannelConfig,
+       #[cfg(not(any(test, feature = "_test_utils")))]
        config: ChannelConfig,
 
        user_id: u64,
@@ -348,7 +380,7 @@ pub(super) struct Channel<Signer: Sign> {
        latest_monitor_update_id: u64,
 
        holder_signer: Signer,
-       shutdown_pubkey: PublicKey,
+       shutdown_scriptpubkey: Option<ShutdownScript>,
        destination_script: Script,
 
        // Our commitment numbers start at 2^48-1 and count down, whereas the ones used in transaction
@@ -401,10 +433,10 @@ pub(super) struct Channel<Signer: Sign> {
 
        #[cfg(debug_assertions)]
        /// Max to_local and to_remote outputs in a locally-generated commitment transaction
-       holder_max_commitment_tx_output: ::std::sync::Mutex<(u64, u64)>,
+       holder_max_commitment_tx_output: Mutex<(u64, u64)>,
        #[cfg(debug_assertions)]
        /// Max to_local and to_remote outputs in a remote-generated commitment transaction
-       counterparty_max_commitment_tx_output: ::std::sync::Mutex<(u64, u64)>,
+       counterparty_max_commitment_tx_output: Mutex<(u64, u64)>,
 
        last_sent_closing_fee: Option<(u32, u64, Signature)>, // (feerate, fee, holder_sig)
 
@@ -492,7 +524,6 @@ struct CommitmentTxInfoCached {
 }
 
 pub const OUR_MAX_HTLCS: u16 = 50; //TODO
-const SPENDING_INPUT_FOR_A_OUTPUT_WEIGHT: u64 = 79; // prevout: 36, nSequence: 4, script len: 1, witness lengths: (3+1)/4, sig: 73/4, if-selector: 1, redeemScript: (6 ops + 2*33 pubkeys + 1*2 delay)/4
 
 #[cfg(not(test))]
 const COMMITMENT_TX_BASE_WEIGHT: u64 = 724;
@@ -567,7 +598,7 @@ impl<Signer: Sign> Channel<Signer> {
        }
 
        // Constructors:
-       pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, APIError>
+       pub fn new_outbound<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: &InitFeatures, channel_value_satoshis: u64, push_msat: u64, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, APIError>
        where K::Target: KeysInterface<Signer = Signer>,
              F::Target: FeeEstimator,
        {
@@ -595,6 +626,16 @@ impl<Signer: Sign> Channel<Signer> {
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&keys_provider.get_secure_random_bytes());
 
+               let shutdown_scriptpubkey = if config.channel_options.commit_upfront_shutdown_pubkey {
+                       Some(keys_provider.get_shutdown_scriptpubkey())
+               } else { None };
+
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
+                       }
+               }
+
                Ok(Channel {
                        user_id,
                        config: config.channel_options.clone(),
@@ -607,7 +648,7 @@ impl<Signer: Sign> Channel<Signer> {
                        latest_monitor_update_id: 0,
 
                        holder_signer,
-                       shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
+                       shutdown_scriptpubkey,
                        destination_script: keys_provider.get_destination_script(),
 
                        cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
@@ -632,9 +673,9 @@ impl<Signer: Sign> Channel<Signer> {
                        monitor_pending_failures: Vec::new(),
 
                        #[cfg(debug_assertions)]
-                       holder_max_commitment_tx_output: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+                       holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
                        #[cfg(debug_assertions)]
-                       counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+                       counterparty_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
 
                        last_sent_closing_fee: None,
 
@@ -703,7 +744,7 @@ impl<Signer: Sign> Channel<Signer> {
 
        /// Creates a new channel from a remote sides' request for one.
        /// Assumes chain_hash has already been checked and corresponds with what we expect!
-       pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, ChannelError>
+       pub fn new_from_req<K: Deref, F: Deref>(fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u64, config: &UserConfig) -> Result<Channel<Signer>, ChannelError>
                where K::Target: KeysInterface<Signer = Signer>,
           F::Target: FeeEstimator
        {
@@ -823,11 +864,11 @@ impl<Signer: Sign> Channel<Signer> {
                                        // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
                                        if script.len() == 0 {
                                                None
-                                       // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
-                                       } else if is_unsupported_shutdown_script(&their_features, script) {
-                                               return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
                                        } else {
-                                               Some(script.clone())
+                                               match ShutdownScript::try_from((script.clone(), their_features)) {
+                                                       Ok(shutdown_script) => Some(shutdown_script.into_inner()),
+                                                       Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+                                               }
                                        }
                                },
                                // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
@@ -837,6 +878,16 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                } else { None };
 
+               let shutdown_scriptpubkey = if config.channel_options.commit_upfront_shutdown_pubkey {
+                       Some(keys_provider.get_shutdown_scriptpubkey())
+               } else { None };
+
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+                       }
+               }
+
                let mut secp_ctx = Secp256k1::new();
                secp_ctx.seeded_randomize(&keys_provider.get_secure_random_bytes());
 
@@ -851,7 +902,7 @@ impl<Signer: Sign> Channel<Signer> {
                        latest_monitor_update_id: 0,
 
                        holder_signer,
-                       shutdown_pubkey: keys_provider.get_shutdown_pubkey(),
+                       shutdown_scriptpubkey,
                        destination_script: keys_provider.get_destination_script(),
 
                        cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
@@ -876,9 +927,9 @@ impl<Signer: Sign> Channel<Signer> {
                        monitor_pending_failures: Vec::new(),
 
                        #[cfg(debug_assertions)]
-                       holder_max_commitment_tx_output: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+                       holder_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
                        #[cfg(debug_assertions)]
-                       counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+                       counterparty_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
 
                        last_sent_closing_fee: None,
 
@@ -1130,8 +1181,10 @@ impl<Signer: Sign> Channel<Signer> {
 
        #[inline]
        fn get_closing_scriptpubkey(&self) -> Script {
-               let channel_close_key_hash = WPubkeyHash::hash(&self.shutdown_pubkey.serialize());
-               Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_close_key_hash[..]).into_script()
+               // The shutdown scriptpubkey is set on channel opening when option_upfront_shutdown_script
+               // is signaled. Otherwise, it is set when sending a shutdown message. Calling this method
+               // outside of those situations will fail.
+               self.shutdown_scriptpubkey.clone().unwrap().into_inner()
        }
 
        #[inline]
@@ -1197,6 +1250,7 @@ impl<Signer: Sign> Channel<Signer> {
                        }, ()));
                }
 
+               assert!(self.shutdown_scriptpubkey.is_some());
                if value_to_self as u64 > self.holder_dust_limit_satoshis {
                        txouts.push((TxOut {
                                script_pubkey: self.get_closing_scriptpubkey(),
@@ -1276,6 +1330,7 @@ impl<Signer: Sign> Channel<Signer> {
                // these, but for now we just have to treat them as normal.
 
                let mut pending_idx = core::usize::MAX;
+               let mut htlc_value_msat = 0;
                for (idx, htlc) in self.pending_inbound_htlcs.iter().enumerate() {
                        if htlc.htlc_id == htlc_id_arg {
                                assert_eq!(htlc.payment_hash, payment_hash_calc);
@@ -1295,6 +1350,7 @@ impl<Signer: Sign> Channel<Signer> {
                                        }
                                }
                                pending_idx = idx;
+                               htlc_value_msat = htlc.amount_msat;
                                break;
                        }
                }
@@ -1336,7 +1392,7 @@ impl<Signer: Sign> Channel<Signer> {
                                                        // TODO: We may actually be able to switch to a fulfill here, though its
                                                        // rare enough it may not be worth the complexity burden.
                                                        debug_assert!(false, "Tried to fulfill an HTLC that was already failed");
-                                                       return UpdateFulfillFetch::NewClaim { monitor_update, msg: None };
+                                                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
                                                }
                                        },
                                        _ => {}
@@ -1348,7 +1404,7 @@ impl<Signer: Sign> Channel<Signer> {
                        });
                        #[cfg(any(test, feature = "fuzztarget"))]
                        self.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
-                       return UpdateFulfillFetch::NewClaim { monitor_update, msg: None };
+                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
                }
                #[cfg(any(test, feature = "fuzztarget"))]
                self.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
@@ -1358,7 +1414,7 @@ impl<Signer: Sign> Channel<Signer> {
                        if let InboundHTLCState::Committed = htlc.state {
                        } else {
                                debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
-                               return UpdateFulfillFetch::NewClaim { monitor_update, msg: None };
+                               return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
                        }
                        log_trace!(logger, "Upgrading HTLC {} to LocalRemoved with a Fulfill in channel {}!", log_bytes!(htlc.payment_hash.0), log_bytes!(self.channel_id));
                        htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(payment_preimage_arg.clone()));
@@ -1366,6 +1422,7 @@ impl<Signer: Sign> Channel<Signer> {
 
                UpdateFulfillFetch::NewClaim {
                        monitor_update,
+                       htlc_value_msat,
                        msg: Some(msgs::UpdateFulfillHTLC {
                                channel_id: self.channel_id(),
                                htlc_id: htlc_id_arg,
@@ -1374,17 +1431,21 @@ impl<Signer: Sign> Channel<Signer> {
                }
        }
 
-       pub fn get_update_fulfill_htlc_and_commit<L: Deref>(&mut self, htlc_id: u64, payment_preimage: PaymentPreimage, logger: &L) -> Result<UpdateFulfillCommitFetch, ChannelError> where L::Target: Logger {
+       pub fn get_update_fulfill_htlc_and_commit<L: Deref>(&mut self, htlc_id: u64, payment_preimage: PaymentPreimage, logger: &L) -> Result<UpdateFulfillCommitFetch, (ChannelError, ChannelMonitorUpdate)> where L::Target: Logger {
                match self.get_update_fulfill_htlc(htlc_id, payment_preimage, logger) {
-                       UpdateFulfillFetch::NewClaim { mut monitor_update, msg: Some(update_fulfill_htlc) } => {
-                               let (commitment, mut additional_update) = self.send_commitment_no_status_check(logger)?;
+                       UpdateFulfillFetch::NewClaim { mut monitor_update, htlc_value_msat, msg: Some(update_fulfill_htlc) } => {
+                               let (commitment, mut additional_update) = match self.send_commitment_no_status_check(logger) {
+                                       Err(e) => return Err((e, monitor_update)),
+                                       Ok(res) => res
+                               };
                                // send_commitment_no_status_check may bump latest_monitor_id but we want them to be
                                // strictly increasing by one, so decrement it here.
                                self.latest_monitor_update_id = monitor_update.update_id;
                                monitor_update.updates.append(&mut additional_update.updates);
-                               Ok(UpdateFulfillCommitFetch::NewClaim { monitor_update, msgs: Some((update_fulfill_htlc, commitment)) })
+                               Ok(UpdateFulfillCommitFetch::NewClaim { monitor_update, htlc_value_msat, msgs: Some((update_fulfill_htlc, commitment)) })
                        },
-                       UpdateFulfillFetch::NewClaim { monitor_update, msg: None } => Ok(UpdateFulfillCommitFetch::NewClaim { monitor_update, msgs: None }),
+                       UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None } =>
+                               Ok(UpdateFulfillCommitFetch::NewClaim { monitor_update, htlc_value_msat, msgs: None }),
                        UpdateFulfillFetch::DuplicateClaim {} => Ok(UpdateFulfillCommitFetch::DuplicateClaim {}),
                }
        }
@@ -1476,7 +1537,7 @@ impl<Signer: Sign> Channel<Signer> {
 
        // Message handlers:
 
-       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: InitFeatures) -> Result<(), ChannelError> {
+       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, config: &UserConfig, their_features: &InitFeatures) -> Result<(), ChannelError> {
                // Check sanity of message fields:
                if !self.is_outbound() {
                        return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
@@ -1547,11 +1608,11 @@ impl<Signer: Sign> Channel<Signer> {
                                        // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
                                        if script.len() == 0 {
                                                None
-                                       // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel
-                                       } else if is_unsupported_shutdown_script(&their_features, script) {
-                                               return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex())));
                                        } else {
-                                               Some(script.clone())
+                                               match ShutdownScript::try_from((script.clone(), their_features)) {
+                                                       Ok(shutdown_script) => Some(shutdown_script.into_inner()),
+                                                       Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script))),
+                                               }
                                        }
                                },
                                // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
@@ -1673,8 +1734,9 @@ impl<Signer: Sign> Channel<Signer> {
                let funding_redeemscript = self.get_funding_redeemscript();
                let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
                let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+               let shutdown_script = self.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
                let channel_monitor = ChannelMonitor::new(self.secp_ctx.clone(), self.holder_signer.clone(),
-                                                         &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+                                                         shutdown_script, self.get_holder_selected_contest_delay(),
                                                          &self.destination_script, (funding_txo, funding_txo_script.clone()),
                                                          &self.channel_transaction_parameters,
                                                          funding_redeemscript.clone(), self.channel_value_satoshis,
@@ -1746,8 +1808,9 @@ impl<Signer: Sign> Channel<Signer> {
                let funding_txo = self.get_funding_txo().unwrap();
                let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
                let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound());
+               let shutdown_script = self.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
                let channel_monitor = ChannelMonitor::new(self.secp_ctx.clone(), self.holder_signer.clone(),
-                                                         &self.shutdown_pubkey, self.get_holder_selected_contest_delay(),
+                                                         shutdown_script, self.get_holder_selected_contest_delay(),
                                                          &self.destination_script, (funding_txo, funding_txo_script),
                                                          &self.channel_transaction_parameters,
                                                          funding_redeemscript.clone(), self.channel_value_satoshis,
@@ -1803,32 +1866,63 @@ impl<Signer: Sign> Channel<Signer> {
                Ok(())
        }
 
-       /// Returns (inbound_htlc_count, htlc_inbound_value_msat)
-       fn get_inbound_pending_htlc_stats(&self) -> (u32, u64) {
-               let mut htlc_inbound_value_msat = 0;
+       /// Returns a HTLCStats about inbound pending htlcs
+       fn get_inbound_pending_htlc_stats(&self) -> HTLCStats {
+               let mut stats = HTLCStats {
+                       pending_htlcs: self.pending_inbound_htlcs.len() as u32,
+                       pending_htlcs_value_msat: 0,
+                       on_counterparty_tx_dust_exposure_msat: 0,
+                       on_holder_tx_dust_exposure_msat: 0,
+               };
+
+               let counterparty_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               let holder_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
                for ref htlc in self.pending_inbound_htlcs.iter() {
-                       htlc_inbound_value_msat += htlc.amount_msat;
+                       stats.pending_htlcs_value_msat += htlc.amount_msat;
+                       if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
+                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
+                       if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
+                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
                }
-               (self.pending_inbound_htlcs.len() as u32, htlc_inbound_value_msat)
+               stats
        }
 
-       /// Returns (outbound_htlc_count, htlc_outbound_value_msat) *including* pending adds in our
-       /// holding cell.
-       fn get_outbound_pending_htlc_stats(&self) -> (u32, u64) {
-               let mut htlc_outbound_value_msat = 0;
+       /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
+       fn get_outbound_pending_htlc_stats(&self) -> HTLCStats {
+               let mut stats = HTLCStats {
+                       pending_htlcs: self.pending_outbound_htlcs.len() as u32,
+                       pending_htlcs_value_msat: 0,
+                       on_counterparty_tx_dust_exposure_msat: 0,
+                       on_holder_tx_dust_exposure_msat: 0,
+               };
+
+               let counterparty_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               let holder_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
                for ref htlc in self.pending_outbound_htlcs.iter() {
-                       htlc_outbound_value_msat += htlc.amount_msat;
+                       stats.pending_htlcs_value_msat += htlc.amount_msat;
+                       if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
+                       if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
                }
 
-               let mut htlc_outbound_count = self.pending_outbound_htlcs.len();
                for update in self.holding_cell_htlc_updates.iter() {
                        if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
-                               htlc_outbound_count += 1;
-                               htlc_outbound_value_msat += amount_msat;
+                               stats.pending_htlcs += 1;
+                               stats.pending_htlcs_value_msat += amount_msat;
+                               if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                                       stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
+                               }
+                               if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                                       stats.on_holder_tx_dust_exposure_msat += amount_msat;
+                               }
                        }
                }
-
-               (htlc_outbound_count as u32, htlc_outbound_value_msat)
+               stats
        }
 
        /// Get the available (ie not including pending HTLCs) inbound and outbound balance in msat.
@@ -1840,11 +1934,11 @@ impl<Signer: Sign> Channel<Signer> {
                (
                        cmp::max(self.channel_value_satoshis as i64 * 1000
                                - self.value_to_self_msat as i64
-                               - self.get_inbound_pending_htlc_stats().1 as i64
+                               - self.get_inbound_pending_htlc_stats().pending_htlcs_value_msat as i64
                                - Self::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) as i64 * 1000,
                        0) as u64,
                        cmp::max(self.value_to_self_msat as i64
-                               - self.get_outbound_pending_htlc_stats().1 as i64
+                               - self.get_outbound_pending_htlc_stats().pending_htlcs_value_msat as i64
                                - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000,
                        0) as u64
                )
@@ -2056,12 +2150,13 @@ impl<Signer: Sign> Channel<Signer> {
                        return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.holder_htlc_minimum_msat, msg.amount_msat)));
                }
 
-               let (inbound_htlc_count, htlc_inbound_value_msat) = self.get_inbound_pending_htlc_stats();
-               if inbound_htlc_count + 1 > OUR_MAX_HTLCS as u32 {
+               let inbound_stats = self.get_inbound_pending_htlc_stats();
+               let outbound_stats = self.get_outbound_pending_htlc_stats();
+               if inbound_stats.pending_htlcs + 1 > OUR_MAX_HTLCS as u32 {
                        return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", OUR_MAX_HTLCS)));
                }
                let holder_max_htlc_value_in_flight_msat = Channel::<Signer>::get_holder_max_htlc_value_in_flight_msat(self.channel_value_satoshis);
-               if htlc_inbound_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
+               if inbound_stats.pending_htlcs_value_msat + msg.amount_msat > holder_max_htlc_value_in_flight_msat {
                        return Err(ChannelError::Close(format!("Remote HTLC add would put them over our max HTLC value ({})", holder_max_htlc_value_in_flight_msat)));
                }
                // Check holder_selected_channel_reserve_satoshis (we're getting paid, so they have to at least meet
@@ -2085,8 +2180,28 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
+               let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
+                       let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_counterparty_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
+                       }
+               }
+
+               let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+               if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
+                       if on_holder_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                               pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
+                       }
+               }
+
                let pending_value_to_self_msat =
-                       self.value_to_self_msat + htlc_inbound_value_msat - removed_outbound_total_msat;
+                       self.value_to_self_msat + inbound_stats.pending_htlcs_value_msat - removed_outbound_total_msat;
                let pending_remote_value_msat =
                        self.channel_value_satoshis * 1000 - pending_value_to_self_msat;
                if pending_remote_value_msat < msg.amount_msat {
@@ -2161,7 +2276,7 @@ impl<Signer: Sign> Channel<Signer> {
 
        /// Marks an outbound HTLC which we have received update_fail/fulfill/malformed
        #[inline]
-       fn mark_outbound_htlc_removed(&mut self, htlc_id: u64, check_preimage: Option<PaymentHash>, fail_reason: Option<HTLCFailReason>) -> Result<&HTLCSource, ChannelError> {
+       fn mark_outbound_htlc_removed(&mut self, htlc_id: u64, check_preimage: Option<PaymentHash>, fail_reason: Option<HTLCFailReason>) -> Result<&OutboundHTLCOutput, ChannelError> {
                for htlc in self.pending_outbound_htlcs.iter_mut() {
                        if htlc.htlc_id == htlc_id {
                                match check_preimage {
@@ -2180,13 +2295,13 @@ impl<Signer: Sign> Channel<Signer> {
                                        OutboundHTLCState::AwaitingRemoteRevokeToRemove(_) | OutboundHTLCState::AwaitingRemovedRemoteRevoke(_) | OutboundHTLCState::RemoteRemoved(_) =>
                                                return Err(ChannelError::Close(format!("Remote tried to fulfill/fail HTLC ({}) that they'd already fulfilled/failed", htlc_id))),
                                }
-                               return Ok(&htlc.source);
+                               return Ok(htlc);
                        }
                }
                Err(ChannelError::Close("Remote tried to fulfill/fail an HTLC we couldn't find".to_owned()))
        }
 
-       pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<HTLCSource, ChannelError> {
+       pub fn update_fulfill_htlc(&mut self, msg: &msgs::UpdateFulfillHTLC) -> Result<(HTLCSource, u64), ChannelError> {
                if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
                        return Err(ChannelError::Close("Got fulfill HTLC message when channel was not in an operational state".to_owned()));
                }
@@ -2195,7 +2310,7 @@ impl<Signer: Sign> Channel<Signer> {
                }
 
                let payment_hash = PaymentHash(Sha256::hash(&msg.payment_preimage.0[..]).into_inner());
-               self.mark_outbound_htlc_removed(msg.htlc_id, Some(payment_hash), None).map(|source| source.clone())
+               self.mark_outbound_htlc_removed(msg.htlc_id, Some(payment_hash), None).map(|htlc| (htlc.source.clone(), htlc.amount_msat))
        }
 
        pub fn update_fail_htlc(&mut self, msg: &msgs::UpdateFailHTLC, fail_reason: HTLCFailReason) -> Result<(), ChannelError> {
@@ -2494,7 +2609,7 @@ impl<Signer: Sign> Channel<Signer> {
                                                // in it hitting the holding cell again and we cannot change the state of a
                                                // holding cell HTLC from fulfill to anything else.
                                                let (update_fulfill_msg_option, mut additional_monitor_update) =
-                                                       if let UpdateFulfillFetch::NewClaim { msg, monitor_update } = self.get_update_fulfill_htlc(htlc_id, *payment_preimage, logger) {
+                                                       if let UpdateFulfillFetch::NewClaim { msg, monitor_update, .. } = self.get_update_fulfill_htlc(htlc_id, *payment_preimage, logger) {
                                                                (msg, monitor_update)
                                                        } else { unreachable!() };
                                                update_fulfill_htlcs.push(update_fulfill_msg_option.unwrap());
@@ -2806,7 +2921,7 @@ impl<Signer: Sign> Channel<Signer> {
                        panic!("Cannot update fee while peer is disconnected/we're awaiting a monitor update (ChannelManager should have caught this)");
                }
 
-               if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == (ChannelState::AwaitingRemoteRevoke as u32) {
+               if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::MonitorUpdateFailed as u32)) != 0 {
                        self.holding_cell_update_fee = Some(feerate_per_kw);
                        return None;
                }
@@ -3030,11 +3145,18 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
-               log_trace!(logger, "Regenerated latest commitment update in channel {} with {} update_adds, {} update_fulfills, {} update_fails, and {} update_fail_malformeds",
-                               log_bytes!(self.channel_id()), update_add_htlcs.len(), update_fulfill_htlcs.len(), update_fail_htlcs.len(), update_fail_malformed_htlcs.len());
+               let update_fee = if self.is_outbound() && self.pending_update_fee.is_some() {
+                       Some(msgs::UpdateFee {
+                               channel_id: self.channel_id(),
+                               feerate_per_kw: self.pending_update_fee.unwrap(),
+                       })
+               } else { None };
+
+               log_trace!(logger, "Regenerated latest commitment update in channel {} with{} {} update_adds, {} update_fulfills, {} update_fails, and {} update_fail_malformeds",
+                               log_bytes!(self.channel_id()), if update_fee.is_some() { " update_fee," } else { "" },
+                               update_add_htlcs.len(), update_fulfill_htlcs.len(), update_fail_htlcs.len(), update_fail_malformed_htlcs.len());
                msgs::CommitmentUpdate {
-                       update_add_htlcs, update_fulfill_htlcs, update_fail_htlcs, update_fail_malformed_htlcs,
-                       update_fee: None,
+                       update_add_htlcs, update_fulfill_htlcs, update_fail_htlcs, update_fail_malformed_htlcs, update_fee,
                        commitment_signed: self.send_commitment_no_state_update(logger).expect("It looks like we failed to re-generate a commitment_signed we had previously sent?").0,
                }
        }
@@ -3078,6 +3200,7 @@ impl<Signer: Sign> Channel<Signer> {
                self.channel_state &= !(ChannelState::PeerDisconnected as u32);
 
                let shutdown_msg = if self.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 {
+                       assert!(self.shutdown_scriptpubkey.is_some());
                        Some(msgs::Shutdown {
                                channel_id: self.channel_id,
                                scriptpubkey: self.get_closing_scriptpubkey(),
@@ -3189,6 +3312,7 @@ impl<Signer: Sign> Channel<Signer> {
                if self.feerate_per_kw > proposed_feerate {
                        proposed_feerate = self.feerate_per_kw;
                }
+               assert!(self.shutdown_scriptpubkey.is_some());
                let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
                let proposed_total_fee_satoshis = proposed_feerate as u64 * tx_weight / 1000;
 
@@ -3207,8 +3331,12 @@ impl<Signer: Sign> Channel<Signer> {
                })
        }
 
-       pub fn shutdown<F: Deref>(&mut self, fee_estimator: &F, their_features: &InitFeatures, msg: &msgs::Shutdown) -> Result<(Option<msgs::Shutdown>, Option<msgs::ClosingSigned>, Vec<(HTLCSource, PaymentHash)>), ChannelError>
-               where F::Target: FeeEstimator
+       pub fn shutdown<F: Deref, K: Deref>(
+               &mut self, fee_estimator: &F, keys_provider: &K, their_features: &InitFeatures, msg: &msgs::Shutdown
+       ) -> Result<(Option<msgs::Shutdown>, Option<msgs::ClosingSigned>, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), ChannelError>
+       where
+               F::Target: FeeEstimator,
+               K::Target: KeysInterface<Signer = Signer>
        {
                if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
                        return Err(ChannelError::Close("Peer sent shutdown when we needed a channel_reestablish".to_owned()));
@@ -3226,23 +3354,58 @@ impl<Signer: Sign> Channel<Signer> {
                }
                assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
-               if is_unsupported_shutdown_script(&their_features, &msg.scriptpubkey) {
-                       return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex())));
-               }
+               let shutdown_scriptpubkey = match ShutdownScript::try_from((msg.scriptpubkey.clone(), their_features)) {
+                       Ok(script) => script.into_inner(),
+                       Err(_) => return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex()))),
+               };
 
                if self.counterparty_shutdown_scriptpubkey.is_some() {
-                       if Some(&msg.scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
-                               return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", msg.scriptpubkey.to_bytes().to_hex())));
+                       if Some(&shutdown_scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() {
+                               return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", shutdown_scriptpubkey.to_bytes().to_hex())));
                        }
                } else {
-                       self.counterparty_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone());
+                       self.counterparty_shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
                }
 
+               // If we have any LocalAnnounced updates we'll probably just get back an update_fail_htlc
+               // immediately after the commitment dance, but we can send a Shutdown because we won't send
+               // any further commitment updates after we set LocalShutdownSent.
+               let send_shutdown = (self.channel_state & ChannelState::LocalShutdownSent as u32) != ChannelState::LocalShutdownSent as u32;
+
+               let update_shutdown_script = match self.shutdown_scriptpubkey {
+                       Some(_) => false,
+                       None => {
+                               assert!(send_shutdown);
+                               let shutdown_scriptpubkey = keys_provider.get_shutdown_scriptpubkey();
+                               if !shutdown_scriptpubkey.is_compatible(their_features) {
+                                       return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+                               }
+                               self.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
+                               true
+                       },
+               };
+
                // From here on out, we may not fail!
 
                self.channel_state |= ChannelState::RemoteShutdownSent as u32;
                self.update_time_counter += 1;
 
+               let monitor_update = if update_shutdown_script {
+                       self.latest_monitor_update_id += 1;
+                       Some(ChannelMonitorUpdate {
+                               update_id: self.latest_monitor_update_id,
+                               updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
+                                       scriptpubkey: self.get_closing_scriptpubkey(),
+                               }],
+                       })
+               } else { None };
+               let shutdown = if send_shutdown {
+                       Some(msgs::Shutdown {
+                               channel_id: self.channel_id,
+                               scriptpubkey: self.get_closing_scriptpubkey(),
+                       })
+               } else { None };
+
                // We can't send our shutdown until we've committed all of our pending HTLCs, but the
                // remote side is unlikely to accept any new HTLCs, so we go ahead and "free" any holding
                // cell HTLCs and return them to fail the payment.
@@ -3257,23 +3420,11 @@ impl<Signer: Sign> Channel<Signer> {
                                _ => true
                        }
                });
-               // If we have any LocalAnnounced updates we'll probably just get back a update_fail_htlc
-               // immediately after the commitment dance, but we can send a Shutdown cause we won't send
-               // any further commitment updates after we set LocalShutdownSent.
-
-               let shutdown = if (self.channel_state & ChannelState::LocalShutdownSent as u32) == ChannelState::LocalShutdownSent as u32 {
-                       None
-               } else {
-                       Some(msgs::Shutdown {
-                               channel_id: self.channel_id,
-                               scriptpubkey: self.get_closing_scriptpubkey(),
-                       })
-               };
 
                self.channel_state |= ChannelState::LocalShutdownSent as u32;
                self.update_time_counter += 1;
 
-               Ok((shutdown, self.maybe_propose_first_closing_signed(fee_estimator), dropped_outbound_htlcs))
+               Ok((shutdown, self.maybe_propose_first_closing_signed(fee_estimator), monitor_update, dropped_outbound_htlcs))
        }
 
        fn build_signed_closing_transaction(&self, tx: &mut Transaction, counterparty_sig: &Signature, sig: &Signature) {
@@ -3348,6 +3499,7 @@ impl<Signer: Sign> Channel<Signer> {
 
                macro_rules! propose_new_feerate {
                        ($new_feerate: expr) => {
+                               assert!(self.shutdown_scriptpubkey.is_some());
                                let tx_weight = self.get_closing_transaction_weight(Some(&self.get_closing_scriptpubkey()), Some(self.counterparty_shutdown_scriptpubkey.as_ref().unwrap()));
                                let (closing_tx, used_total_fee) = self.build_closing_transaction($new_feerate as u64 * tx_weight / 1000, false);
                                let sig = self.holder_signer
@@ -3482,18 +3634,30 @@ impl<Signer: Sign> Channel<Signer> {
        }
 
        pub fn get_fee_proportional_millionths(&self) -> u32 {
-               self.config.fee_proportional_millionths
+               self.config.forwarding_fee_proportional_millionths
        }
 
        pub fn get_cltv_expiry_delta(&self) -> u16 {
                cmp::max(self.config.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
        }
 
-       #[cfg(test)]
+       pub fn get_max_dust_htlc_exposure_msat(&self) -> u64 {
+               self.config.max_dust_htlc_exposure_msat
+       }
+
        pub fn get_feerate(&self) -> u32 {
                self.feerate_per_kw
        }
 
+       pub fn get_dust_buffer_feerate(&self) -> u32 {
+               // When calculating our exposure to dust HTLCs, we assume that the channel feerate
+               // may, at any point, increase by at least 10 sat/vB (i.e 2530 sat/kWU) or 25%,
+               // whichever is higher. This ensures that we aren't suddenly exposed to significantly
+               // more dust balance if the feerate increases when we have several HTLCs pending
+               // which are near the dust limit.
+               cmp::max(2530, self.feerate_per_kw * 1250 / 1000)
+       }
+
        pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
                self.cur_holder_commitment_transaction_number + 1
        }
@@ -3555,24 +3719,8 @@ impl<Signer: Sign> Channel<Signer> {
 
        /// Gets the fee we'd want to charge for adding an HTLC output to this Channel
        /// Allowed in any state (including after shutdown)
-       pub fn get_holder_fee_base_msat<F: Deref>(&self, fee_estimator: &F) -> u32
-               where F::Target: FeeEstimator
-       {
-               // For lack of a better metric, we calculate what it would cost to consolidate the new HTLC
-               // output value back into a transaction with the regular channel output:
-
-               // the fee cost of the HTLC-Success/HTLC-Timeout transaction:
-               let mut res = self.feerate_per_kw as u64 * cmp::max(HTLC_TIMEOUT_TX_WEIGHT, HTLC_SUCCESS_TX_WEIGHT) / 1000;
-
-               if self.is_outbound() {
-                       // + the marginal fee increase cost to us in the commitment transaction:
-                       res += self.feerate_per_kw as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC / 1000;
-               }
-
-               // + the marginal cost of an input which spends the HTLC-Success/HTLC-Timeout output:
-               res += fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal) as u64 * SPENDING_INPUT_FOR_A_OUTPUT_WEIGHT / 1000;
-
-               res as u32
+       pub fn get_outbound_forwarding_fee_base_msat(&self) -> u32 {
+               self.config.forwarding_fee_base_msat
        }
 
        /// Returns true if we've ever received a message from the remote end for this Channel
@@ -3862,7 +4010,10 @@ impl<Signer: Sign> Channel<Signer> {
                        htlc_basepoint: keys.htlc_basepoint,
                        first_per_commitment_point,
                        channel_flags: if self.config.announced_channel {1} else {0},
-                       shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
+                       shutdown_scriptpubkey: OptionalField::Present(match &self.shutdown_scriptpubkey {
+                               Some(script) => script.clone().into_inner(),
+                               None => Builder::new().into_script(),
+                       }),
                }
        }
 
@@ -3895,7 +4046,10 @@ impl<Signer: Sign> Channel<Signer> {
                        delayed_payment_basepoint: keys.delayed_payment_basepoint,
                        htlc_basepoint: keys.htlc_basepoint,
                        first_per_commitment_point,
-                       shutdown_scriptpubkey: OptionalField::Present(if self.config.commit_upfront_shutdown_pubkey { self.get_closing_scriptpubkey() } else { Builder::new().into_script() })
+                       shutdown_scriptpubkey: OptionalField::Present(match &self.shutdown_scriptpubkey {
+                               Some(script) => script.clone().into_inner(),
+                               None => Builder::new().into_script(),
+                       }),
                }
        }
 
@@ -4148,19 +4302,20 @@ impl<Signer: Sign> Channel<Signer> {
                        return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned()));
                }
 
-               let (outbound_htlc_count, htlc_outbound_value_msat) = self.get_outbound_pending_htlc_stats();
-               if outbound_htlc_count + 1 > self.counterparty_max_accepted_htlcs as u32 {
+               let inbound_stats = self.get_inbound_pending_htlc_stats();
+               let outbound_stats = self.get_outbound_pending_htlc_stats();
+               if outbound_stats.pending_htlcs + 1 > self.counterparty_max_accepted_htlcs as u32 {
                        return Err(ChannelError::Ignore(format!("Cannot push more than their max accepted HTLCs ({})", self.counterparty_max_accepted_htlcs)));
                }
                // Check their_max_htlc_value_in_flight_msat
-               if htlc_outbound_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
+               if outbound_stats.pending_htlcs_value_msat + amount_msat > self.counterparty_max_htlc_value_in_flight_msat {
                        return Err(ChannelError::Ignore(format!("Cannot send value that would put us over the max HTLC value in flight our peer will accept ({})", self.counterparty_max_htlc_value_in_flight_msat)));
                }
 
                if !self.is_outbound() {
                        // Check that we won't violate the remote channel reserve by adding this HTLC.
                        let counterparty_balance_msat = self.channel_value_satoshis * 1000 - self.value_to_self_msat;
-                       let holder_selected_chan_reserve_msat = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis);
+                       let holder_selected_chan_reserve_msat = Channel::<Signer>::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) * 1000;
                        let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered);
                        let counterparty_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(htlc_candidate, None);
                        if counterparty_balance_msat < holder_selected_chan_reserve_msat + counterparty_commit_tx_fee_msat {
@@ -4168,7 +4323,25 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                }
 
-               let pending_value_to_self_msat = self.value_to_self_msat - htlc_outbound_value_msat;
+               let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis;
+               if amount_msat / 1000 < exposure_dust_limit_success_sats {
+                       let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + amount_msat;
+                       if on_counterparty_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               return Err(ChannelError::Ignore(format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
+                                       on_counterparty_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat())));
+                       }
+               }
+
+               let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis;
+               if amount_msat / 1000 <  exposure_dust_limit_timeout_sats {
+                       let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + amount_msat;
+                       if on_holder_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                               return Err(ChannelError::Ignore(format!("Cannot send value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
+                                       on_holder_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat())));
+                       }
+               }
+
+               let pending_value_to_self_msat = self.value_to_self_msat - outbound_stats.pending_htlcs_value_msat;
                if pending_value_to_self_msat < amount_msat {
                        return Err(ChannelError::Ignore(format!("Cannot send value that would overdraw remaining funds. Amount: {}, pending value to self {}", amount_msat, pending_value_to_self_msat)));
                }
@@ -4176,7 +4349,7 @@ impl<Signer: Sign> Channel<Signer> {
                // `2 *` and extra HTLC are for the fee spike buffer.
                let commit_tx_fee_msat = if self.is_outbound() {
                        let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered);
-                       2 * self.next_local_commit_tx_fee_msat(htlc_candidate, Some(()))
+                       FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * self.next_local_commit_tx_fee_msat(htlc_candidate, Some(()))
                } else { 0 };
                if pending_value_to_self_msat - amount_msat < commit_tx_fee_msat {
                        return Err(ChannelError::Ignore(format!("Cannot send value that would not leave enough to pay for fees. Pending value to self: {}. local_commit_tx_fee {}", pending_value_to_self_msat, commit_tx_fee_msat)));
@@ -4403,7 +4576,8 @@ impl<Signer: Sign> Channel<Signer> {
 
        /// Begins the shutdown process, getting a message for the remote peer and returning all
        /// holding cell HTLCs for payment failure.
-       pub fn get_shutdown(&mut self) -> Result<(msgs::Shutdown, Vec<(HTLCSource, PaymentHash)>), APIError> {
+       pub fn get_shutdown<K: Deref>(&mut self, keys_provider: &K, their_features: &InitFeatures) -> Result<(msgs::Shutdown, Option<ChannelMonitorUpdate>, Vec<(HTLCSource, PaymentHash)>), APIError>
+       where K::Target: KeysInterface<Signer = Signer> {
                for htlc in self.pending_outbound_htlcs.iter() {
                        if let OutboundHTLCState::LocalAnnounced(_) = htlc.state {
                                return Err(APIError::APIMisuseError{err: "Cannot begin shutdown with pending HTLCs. Process pending events first".to_owned()});
@@ -4422,7 +4596,17 @@ impl<Signer: Sign> Channel<Signer> {
                        return Err(APIError::ChannelUnavailable{err: "Cannot begin shutdown while peer is disconnected or we're waiting on a monitor update, maybe force-close instead?".to_owned()});
                }
 
-               let closing_script = self.get_closing_scriptpubkey();
+               let update_shutdown_script = match self.shutdown_scriptpubkey {
+                       Some(_) => false,
+                       None => {
+                               let shutdown_scriptpubkey = keys_provider.get_shutdown_scriptpubkey();
+                               if !shutdown_scriptpubkey.is_compatible(their_features) {
+                                       return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
+                               }
+                               self.shutdown_scriptpubkey = Some(shutdown_scriptpubkey);
+                               true
+                       },
+               };
 
                // From here on out, we may not fail!
                if self.channel_state < ChannelState::FundingSent as u32 {
@@ -4432,6 +4616,20 @@ impl<Signer: Sign> Channel<Signer> {
                }
                self.update_time_counter += 1;
 
+               let monitor_update = if update_shutdown_script {
+                       self.latest_monitor_update_id += 1;
+                       Some(ChannelMonitorUpdate {
+                               update_id: self.latest_monitor_update_id,
+                               updates: vec![ChannelMonitorUpdateStep::ShutdownScript {
+                                       scriptpubkey: self.get_closing_scriptpubkey(),
+                               }],
+                       })
+               } else { None };
+               let shutdown = msgs::Shutdown {
+                       channel_id: self.channel_id,
+                       scriptpubkey: self.get_closing_scriptpubkey(),
+               };
+
                // Go ahead and drop holding cell updates as we'd rather fail payments than wait to send
                // our shutdown until we've committed all of the pending changes.
                self.holding_cell_update_fee = None;
@@ -4446,10 +4644,7 @@ impl<Signer: Sign> Channel<Signer> {
                        }
                });
 
-               Ok((msgs::Shutdown {
-                       channel_id: self.channel_id,
-                       scriptpubkey: closing_script,
-               }, dropped_outbound_htlcs))
+               Ok((shutdown, monitor_update, dropped_outbound_htlcs))
        }
 
        /// Gets the latest commitment transaction and any dependent transactions for relay (forcing
@@ -4498,25 +4693,7 @@ impl<Signer: Sign> Channel<Signer> {
        }
 }
 
-fn is_unsupported_shutdown_script(their_features: &InitFeatures, script: &Script) -> bool {
-       // We restrain shutdown scripts to standards forms to avoid transactions not propagating on the p2p tx-relay network
-
-       // BOLT 2 says we must only send a scriptpubkey of certain standard forms,
-       // which for a a BIP-141-compliant witness program is at max 42 bytes in length.
-       // So don't let the remote peer feed us some super fee-heavy script.
-       let is_script_too_long = script.len() > 42;
-       if is_script_too_long {
-               return true;
-       }
-
-       if their_features.supports_shutdown_anysegwit() && script.is_witness_program() && script.as_bytes()[0] != OP_PUSHBYTES_0.into_u8() {
-               return false;
-       }
-
-       return !script.is_p2pkh() && !script.is_p2sh() && !script.is_v0_p2wpkh() && !script.is_v0_p2wsh()
-}
-
-const SERIALIZATION_VERSION: u8 = 1;
+const SERIALIZATION_VERSION: u8 = 2;
 const MIN_SERIALIZATION_VERSION: u8 = 1;
 
 impl_writeable_tlv_based_enum!(InboundHTLCRemovalReason,;
@@ -4526,7 +4703,7 @@ impl_writeable_tlv_based_enum!(InboundHTLCRemovalReason,;
 );
 
 impl Writeable for ChannelUpdateStatus {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                // We only care about writing out the current state as it was announced, ie only either
                // Enabled or Disabled. In the case of DisabledStaged, we most recently announced the
                // channel as enabled, so we write 0. For EnabledStaged, we similarly write a 1.
@@ -4541,7 +4718,7 @@ impl Writeable for ChannelUpdateStatus {
 }
 
 impl Readable for ChannelUpdateStatus {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
                Ok(match <u8 as Readable>::read(reader)? {
                        0 => ChannelUpdateStatus::Enabled,
                        1 => ChannelUpdateStatus::Disabled,
@@ -4551,14 +4728,20 @@ impl Readable for ChannelUpdateStatus {
 }
 
 impl<Signer: Sign> Writeable for Channel<Signer> {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
                // Note that we write out as if remove_uncommitted_htlcs_and_mark_paused had just been
                // called.
 
                write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 
                self.user_id.write(writer)?;
-               self.config.write(writer)?;
+
+               // Write out the old serialization for the config object. This is read by version-1
+               // deserializers, but we will read the version in the TLV at the end instead.
+               self.config.forwarding_fee_proportional_millionths.write(writer)?;
+               self.config.cltv_expiry_delta.write(writer)?;
+               self.config.announced_channel.write(writer)?;
+               self.config.commit_upfront_shutdown_pubkey.write(writer)?;
 
                self.channel_id.write(writer)?;
                (self.channel_state | ChannelState::PeerDisconnected as u32).write(writer)?;
@@ -4573,7 +4756,12 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
                (key_data.0.len() as u32).write(writer)?;
                writer.write_all(&key_data.0[..])?;
 
-               self.shutdown_pubkey.write(writer)?;
+               // Write out the old serialization for shutdown_pubkey for backwards compatibility, if
+               // deserialized from that format.
+               match self.shutdown_scriptpubkey.as_ref().and_then(|script| script.as_legacy_pubkey()) {
+                       Some(shutdown_pubkey) => shutdown_pubkey.write(writer)?,
+                       None => [0u8; PUBLIC_KEY_SIZE].write(writer)?,
+               }
                self.destination_script.write(writer)?;
 
                self.cur_holder_commitment_transaction_number.write(writer)?;
@@ -4717,10 +4905,15 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
                self.counterparty_dust_limit_satoshis.write(writer)?;
                self.holder_dust_limit_satoshis.write(writer)?;
                self.counterparty_max_htlc_value_in_flight_msat.write(writer)?;
+
+               // Note that this field is ignored by 0.0.99+ as the TLV Optional variant is used instead.
                self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0).write(writer)?;
+
                self.counterparty_htlc_minimum_msat.write(writer)?;
                self.holder_htlc_minimum_msat.write(writer)?;
                self.counterparty_max_accepted_htlcs.write(writer)?;
+
+               // Note that this field is ignored by 0.0.99+ as the TLV Optional variant is used instead.
                self.minimum_depth.unwrap_or(0).write(writer)?;
 
                match &self.counterparty_forwarding_info {
@@ -4763,6 +4956,8 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
                        // override that.
                        (1, self.minimum_depth, option),
                        (3, self.counterparty_selected_channel_reserve_satoshis, option),
+                       (5, self.config, required),
+                       (7, self.shutdown_scriptpubkey, option),
                });
 
                Ok(())
@@ -4772,11 +4967,22 @@ impl<Signer: Sign> Writeable for Channel<Signer> {
 const MAX_ALLOC_SIZE: usize = 64*1024;
 impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                where K::Target: KeysInterface<Signer = Signer> {
-       fn read<R : ::std::io::Read>(reader: &mut R, keys_source: &'a K) -> Result<Self, DecodeError> {
-               let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
+       fn read<R : io::Read>(reader: &mut R, keys_source: &'a K) -> Result<Self, DecodeError> {
+               let ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 
                let user_id = Readable::read(reader)?;
-               let config: ChannelConfig = Readable::read(reader)?;
+
+               let mut config = Some(ChannelConfig::default());
+               if ver == 1 {
+                       // Read the old serialization of the ChannelConfig from version 0.0.98.
+                       config.as_mut().unwrap().forwarding_fee_proportional_millionths = Readable::read(reader)?;
+                       config.as_mut().unwrap().cltv_expiry_delta = Readable::read(reader)?;
+                       config.as_mut().unwrap().announced_channel = Readable::read(reader)?;
+                       config.as_mut().unwrap().commit_upfront_shutdown_pubkey = Readable::read(reader)?;
+               } else {
+                       // Read the 8 bytes of backwards-compatibility ChannelConfig data.
+                       let mut _val: u64 = Readable::read(reader)?;
+               }
 
                let channel_id = Readable::read(reader)?;
                let channel_state = Readable::read(reader)?;
@@ -4795,7 +5001,11 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                }
                let holder_signer = keys_source.read_chan_signer(&keys_data)?;
 
-               let shutdown_pubkey = Readable::read(reader)?;
+               // Read the old serialization for shutdown_pubkey, preferring the TLV field later if set.
+               let mut shutdown_scriptpubkey = match <PublicKey as Readable>::read(reader) {
+                       Ok(pubkey) => Some(ShutdownScript::new_p2wpkh_from_pubkey(pubkey)),
+                       Err(_) => None,
+               };
                let destination_script = Readable::read(reader)?;
 
                let cur_holder_commitment_transaction_number = Readable::read(reader)?;
@@ -4906,20 +5116,25 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                let counterparty_dust_limit_satoshis = Readable::read(reader)?;
                let holder_dust_limit_satoshis = Readable::read(reader)?;
                let counterparty_max_htlc_value_in_flight_msat = Readable::read(reader)?;
-               let mut counterparty_selected_channel_reserve_satoshis = Some(Readable::read(reader)?);
-               if counterparty_selected_channel_reserve_satoshis == Some(0) {
-                       // Versions up to 0.0.98 had counterparty_selected_channel_reserve_satoshis as a
-                       // non-option, writing 0 for what we now consider None.
-                       counterparty_selected_channel_reserve_satoshis = None;
+               let mut counterparty_selected_channel_reserve_satoshis = None;
+               if ver == 1 {
+                       // Read the old serialization from version 0.0.98.
+                       counterparty_selected_channel_reserve_satoshis = Some(Readable::read(reader)?);
+               } else {
+                       // Read the 8 bytes of backwards-compatibility data.
+                       let _dummy: u64 = Readable::read(reader)?;
                }
                let counterparty_htlc_minimum_msat = Readable::read(reader)?;
                let holder_htlc_minimum_msat = Readable::read(reader)?;
                let counterparty_max_accepted_htlcs = Readable::read(reader)?;
-               let mut minimum_depth = Some(Readable::read(reader)?);
-               if minimum_depth == Some(0) {
-                       // Versions up to 0.0.98 had minimum_depth as a non-option, writing 0 for what we now
-                       // consider None.
-                       minimum_depth = None;
+
+               let mut minimum_depth = None;
+               if ver == 1 {
+                       // Read the old serialization from version 0.0.98.
+                       minimum_depth = Some(Readable::read(reader)?);
+               } else {
+                       // Read the 4 bytes of backwards-compatibility data.
+                       let _dummy: u32 = Readable::read(reader)?;
                }
 
                let counterparty_forwarding_info = match <u8 as Readable>::read(reader)? {
@@ -4960,6 +5175,8 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        (0, announcement_sigs, option),
                        (1, minimum_depth, option),
                        (3, counterparty_selected_channel_reserve_satoshis, option),
+                       (5, config, option), // Note that if none is provided we will *not* overwrite the existing one.
+                       (7, shutdown_scriptpubkey, option),
                });
 
                let mut secp_ctx = Secp256k1::new();
@@ -4968,7 +5185,7 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                Ok(Channel {
                        user_id,
 
-                       config,
+                       config: config.unwrap(),
                        channel_id,
                        channel_state,
                        secp_ctx,
@@ -4977,7 +5194,7 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        latest_monitor_update_id,
 
                        holder_signer,
-                       shutdown_pubkey,
+                       shutdown_scriptpubkey,
                        destination_script,
 
                        cur_holder_commitment_transaction_number,
@@ -5004,9 +5221,9 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<&'a K> for Channel<Signer>
                        feerate_per_kw,
 
                        #[cfg(debug_assertions)]
-                       holder_max_commitment_tx_output: ::std::sync::Mutex::new((0, 0)),
+                       holder_max_commitment_tx_output: Mutex::new((0, 0)),
                        #[cfg(debug_assertions)]
-                       counterparty_max_commitment_tx_output: ::std::sync::Mutex::new((0, 0)),
+                       counterparty_max_commitment_tx_output: Mutex::new((0, 0)),
 
                        last_sent_closing_fee,
 
@@ -5070,6 +5287,7 @@ mod tests {
        use ln::channel::MAX_FUNDING_SATOSHIS;
        use ln::features::InitFeatures;
        use ln::msgs::{ChannelUpdate, DataLossProtect, DecodeError, OptionalField, UnsignedChannelUpdate};
+       use ln::script::ShutdownScript;
        use ln::chan_utils;
        use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT};
        use chain::BestBlock;
@@ -5078,7 +5296,9 @@ mod tests {
        use chain::transaction::OutPoint;
        use util::config::UserConfig;
        use util::enforcing_trait_impls::EnforcingSigner;
+       use util::errors::APIError;
        use util::test_utils;
+       use util::test_utils::OnGetShutdownScriptpubkey;
        use util::logger::Logger;
        use bitcoin::secp256k1::{Secp256k1, Message, Signature, All};
        use bitcoin::secp256k1::ffi::Signature as FFISignature;
@@ -5087,7 +5307,8 @@ mod tests {
        use bitcoin::hashes::sha256::Hash as Sha256;
        use bitcoin::hashes::Hash;
        use bitcoin::hash_types::{Txid, WPubkeyHash};
-       use std::sync::Arc;
+       use core::num::NonZeroU8;
+       use sync::Arc;
        use prelude::*;
 
        struct TestFeeEstimator {
@@ -5119,10 +5340,10 @@ mod tests {
                        Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&channel_monitor_claim_key_hash[..]).into_script()
                }
 
-               fn get_shutdown_pubkey(&self) -> PublicKey {
+               fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
                        let secp_ctx = Secp256k1::signing_only();
                        let channel_close_key = SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap();
-                       PublicKey::from_secret_key(&secp_ctx, &channel_close_key)
+                       ShutdownScript::new_p2wpkh_from_pubkey(PublicKey::from_secret_key(&secp_ctx, &channel_close_key))
                }
 
                fn get_channel_signer(&self, _inbound: bool, _channel_value_satoshis: u64) -> InMemorySigner {
@@ -5137,6 +5358,32 @@ mod tests {
                PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode(hex).unwrap()[..]).unwrap())
        }
 
+       #[test]
+       fn upfront_shutdown_script_incompatibility() {
+               let features = InitFeatures::known().clear_shutdown_anysegwit();
+               let non_v0_segwit_shutdown_script =
+                       ShutdownScript::new_witness_program(NonZeroU8::new(16).unwrap(), &[0, 40]).unwrap();
+
+               let seed = [42; 32];
+               let network = Network::Testnet;
+               let keys_provider = test_utils::TestKeysInterface::new(&seed, network);
+               keys_provider.expect(OnGetShutdownScriptpubkey {
+                       returns: non_v0_segwit_shutdown_script.clone(),
+               });
+
+               let fee_estimator = TestFeeEstimator { fee_est: 253 };
+               let secp_ctx = Secp256k1::new();
+               let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+               let config = UserConfig::default();
+               match Channel::<EnforcingSigner>::new_outbound(&&fee_estimator, &&keys_provider, node_id, &features, 10000000, 100000, 42, &config) {
+                       Err(APIError::IncompatibleShutdownScript { script }) => {
+                               assert_eq!(script.into_inner(), non_v0_segwit_shutdown_script.into_inner());
+                       },
+                       Err(e) => panic!("Unexpected error: {:?}", e),
+                       Ok(_) => panic!("Expected error"),
+               }
+       }
+
        // Check that, during channel creation, we use the same feerate in the open channel message
        // as we do in the Channel object creation itself.
        #[test]
@@ -5150,7 +5397,7 @@ mod tests {
 
                let node_a_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
-               let node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, 10000000, 100000, 42, &config).unwrap();
+               let node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_a_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
 
                // Now change the fee so we can check that the fee in the open_channel message is the
                // same as the old fee.
@@ -5175,18 +5422,18 @@ mod tests {
                // Create Node A's channel pointing to Node B's pubkey
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
-               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
 
                // Create Node B's channel by receiving Node A's open_channel message
                // Make sure A's dust limit is as we expect.
                let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash());
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
-               let node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+               let node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
 
                // Node B --> Node A: accept channel, explicitly setting B's dust limit.
                let mut accept_channel_msg = node_b_chan.get_accept_channel();
                accept_channel_msg.dust_limit_satoshis = 546;
-               node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap();
+               node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
                node_a_chan.holder_dust_limit_satoshis = 1560;
 
                // Put some inbound and outbound HTLCs in A's channel.
@@ -5242,7 +5489,7 @@ mod tests {
 
                let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
-               let mut chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_id, 10000000, 100000, 42, &config).unwrap();
+               let mut chan = Channel::<EnforcingSigner>::new_outbound(&&fee_est, &&keys_provider, node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
 
                let commitment_tx_fee_0_htlcs = chan.commit_tx_fee_msat(0);
                let commitment_tx_fee_1_htlc = chan.commit_tx_fee_msat(1);
@@ -5291,16 +5538,16 @@ mod tests {
                // Create Node A's channel pointing to Node B's pubkey
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
-               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
 
                // Create Node B's channel by receiving Node A's open_channel message
                let open_channel_msg = node_a_chan.get_open_channel(chain_hash);
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap());
-               let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
+               let mut node_b_chan = Channel::<EnforcingSigner>::new_from_req(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), &open_channel_msg, 7, &config).unwrap();
 
                // Node B --> Node A: accept channel
                let accept_channel_msg = node_b_chan.get_accept_channel();
-               node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap();
+               node_a_chan.accept_channel(&accept_channel_msg, &config, &InitFeatures::known()).unwrap();
 
                // Node A --> Node B: funding created
                let output_script = node_a_chan.get_funding_redeemscript();
@@ -5353,7 +5600,7 @@ mod tests {
                // Create a channel.
                let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let config = UserConfig::default();
-               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap();
+               let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&&feeest, &&keys_provider, node_b_node_id, &InitFeatures::known(), 10000000, 100000, 42, &config).unwrap();
                assert!(node_a_chan.counterparty_forwarding_info.is_none());
                assert_eq!(node_a_chan.holder_htlc_minimum_msat, 1); // the default
                assert!(node_a_chan.counterparty_forwarding_info().is_none());
@@ -5417,7 +5664,7 @@ mod tests {
                let counterparty_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
                let mut config = UserConfig::default();
                config.channel_options.announced_channel = false;
-               let mut chan = Channel::<InMemorySigner>::new_outbound(&&feeest, &&keys_provider, counterparty_node_id, 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
+               let mut chan = Channel::<InMemorySigner>::new_outbound(&&feeest, &&keys_provider, counterparty_node_id, &InitFeatures::known(), 10_000_000, 100000, 42, &config).unwrap(); // Nothing uses their network key in this test
                chan.holder_dust_limit_satoshis = 546;
                chan.counterparty_selected_channel_reserve_satoshis = Some(0); // Filled in in accept_channel