Add ability to broadcast our own node_announcement.
[rust-lightning] / lightning / src / ln / channelmanager.rs
index 5f7e903fd201c6da81c0eadf20dd61d6f98e2dd6..d34e64ac2e884ec6e59d6c0a072097af87318dc1 100644 (file)
@@ -29,8 +29,8 @@ use chain::chaininterface::{BroadcasterInterface,ChainListener,FeeEstimator};
 use chain::transaction::OutPoint;
 use ln::channel::{Channel, ChannelError};
 use ln::channelmonitor::{ChannelMonitor, ChannelMonitorUpdateErr, ManyChannelMonitor, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY};
+use ln::features::{InitFeatures, NodeFeatures};
 use ln::router::Route;
-use ln::features::InitFeatures;
 use ln::msgs;
 use ln::onion_utils;
 use ln::msgs::{ChannelMessageHandler, DecodeError, LightningError};
@@ -368,6 +368,10 @@ pub struct ChannelManager<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref,
        channel_state: Mutex<ChannelHolder<ChanSigner>>,
        our_network_key: SecretKey,
 
+       /// Used to track the last value sent in a node_announcement "timestamp" field. We ensure this
+       /// value increases strictly since we don't assume access to a time source.
+       last_node_announcement_serial: AtomicUsize,
+
        /// The bulk of our storage will eventually be here (channels and message queues and the like).
        /// If we are connected to a peer we always at least have an entry here, even if no channels
        /// are currently open with that peer.
@@ -665,6 +669,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                        }),
                        our_network_key: keys_manager.get_node_secret(),
 
+                       last_node_announcement_serial: AtomicUsize::new(0),
+
                        per_peer_state: RwLock::new(HashMap::new()),
 
                        pending_events: Mutex::new(Vec::new()),
@@ -1334,6 +1340,57 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                })
        }
 
+       #[allow(dead_code)]
+       // Messages of up to 64KB should never end up more than half full with addresses, as that would
+       // be absurd. We ensure this by checking that at least 500 (our stated public contract on when
+       // broadcast_node_announcement panics) of the maximum-length addresses would fit in a 64KB
+       // message...
+       const HALF_MESSAGE_IS_ADDRS: u32 = ::std::u16::MAX as u32 / (msgs::NetAddress::MAX_LEN as u32 + 1) / 2;
+       #[deny(const_err)]
+       #[allow(dead_code)]
+       // ...by failing to compile if the number of addresses that would be half of a message is
+       // smaller than 500:
+       const STATIC_ASSERT: u32 = Self::HALF_MESSAGE_IS_ADDRS - 500;
+
+       /// Generates a signed node_announcement from the given arguments and creates a
+       /// BroadcastNodeAnnouncement event. Note that such messages will be ignored unless peers have
+       /// seen a channel_announcement from us (ie unless we have public channels open).
+       ///
+       /// RGB is a node "color" and alias is a printable human-readable string to describe this node
+       /// to humans. They carry no in-protocol meaning.
+       ///
+       /// addresses represent the set (possibly empty) of socket addresses on which this node accepts
+       /// incoming connections. These will be broadcast to the network, publicly tying these
+       /// addresses together. If you wish to preserve user privacy, addresses should likely contain
+       /// only Tor Onion addresses.
+       ///
+       /// Panics if addresses is absurdly large (more than 500).
+       pub fn broadcast_node_announcement(&self, rgb: [u8; 3], alias: [u8; 32], addresses: Vec<msgs::NetAddress>) {
+               let _ = self.total_consistency_lock.read().unwrap();
+
+               if addresses.len() > 500 {
+                       panic!("More than half the message size was taken up by public addresses!");
+               }
+
+               let announcement = msgs::UnsignedNodeAnnouncement {
+                       features: NodeFeatures::supported(),
+                       timestamp: self.last_node_announcement_serial.fetch_add(1, Ordering::AcqRel) as u32,
+                       node_id: self.get_our_node_id(),
+                       rgb, alias, addresses,
+                       excess_address_data: Vec::new(),
+                       excess_data: Vec::new(),
+               };
+               let msghash = hash_to_message!(&Sha256dHash::hash(&announcement.encode()[..])[..]);
+
+               let mut channel_state = self.channel_state.lock().unwrap();
+               channel_state.pending_msg_events.push(events::MessageSendEvent::BroadcastNodeAnnouncement {
+                       msg: msgs::NodeAnnouncement {
+                               signature: self.secp_ctx.sign(&msghash, &self.our_network_key),
+                               contents: announcement
+                       },
+               });
+       }
+
        /// Processes HTLCs which are pending waiting on random forward delay.
        ///
        /// Should only really ever be called in response to a PendingHTLCsForwardable event.
@@ -2970,6 +3027,7 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
                                        &events::MessageSendEvent::SendShutdown { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::SendChannelReestablish { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::BroadcastChannelAnnouncement { .. } => true,
+                                       &events::MessageSendEvent::BroadcastNodeAnnouncement { .. } => true,
                                        &events::MessageSendEvent::BroadcastChannelUpdate { .. } => true,
                                        &events::MessageSendEvent::HandleError { ref node_id, .. } => node_id != their_node_id,
                                        &events::MessageSendEvent::PaymentFailureNetworkUpdate { .. } => true,
@@ -3288,6 +3346,8 @@ impl<ChanSigner: ChannelKeys + Writeable, M: Deref, T: Deref, K: Deref, F: Deref
                        peer_state.latest_features.write(writer)?;
                }
 
+               (self.last_node_announcement_serial.load(Ordering::Acquire) as u32).write(writer)?;
+
                Ok(())
        }
 }
@@ -3459,6 +3519,8 @@ impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: De
                        per_peer_state.insert(peer_pubkey, Mutex::new(peer_state));
                }
 
+               let last_node_announcement_serial: u32 = Readable::read(reader)?;
+
                let channel_manager = ChannelManager {
                        genesis_hash,
                        fee_estimator: args.fee_estimator,
@@ -3478,6 +3540,8 @@ impl<'a, ChanSigner: ChannelKeys + Readable, M: Deref, T: Deref, K: Deref, F: De
                        }),
                        our_network_key: args.keys_manager.get_node_secret(),
 
+                       last_node_announcement_serial: AtomicUsize::new(last_node_announcement_serial as usize),
+
                        per_peer_state: RwLock::new(per_peer_state),
 
                        pending_events: Mutex::new(Vec::new()),