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Add a Disconnected ChannelState and check/handle it everywhere

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Setting/removing it comes next
This commit is contained in:
Matt Corallo 2018-09-08 16:01:29 -04:00
parent 12a50627a3
commit ca712dfa36
1 changed files with 73 additions and 7 deletions
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80
src/ln/channel.rs
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@ -203,6 +203,13 @@ enum HTLCUpdateAwaitingACK {
},
}
/// There are a few "states" and then a number of flags which can be applied:
/// We first move through init with OurInitSent -> TheirInitSent -> FundingCreated -> FundingSent.
/// TheirFundingLocked and OurFundingLocked then get set on FundingSent, and when both are set we
/// move on to ChannelFunded.
/// Note that PeerDisconnected can be set on both ChannelFunded and FundingSent.
/// ChannelFunded can then get all remaining flags set on it, until we finish shutdown, then we
/// move on to ShutdownComplete, at which point most calls into this channel are disallowed.
enum ChannelState {
/// Implies we have (or are prepared to) send our open_channel/accept_channel message
OurInitSent = (1 << 0),
@ -223,25 +230,29 @@ enum ChannelState {
/// Once both TheirFundingLocked and OurFundingLocked are set, state moves on to ChannelFunded.
OurFundingLocked = (1 << 5),
ChannelFunded = 64,
/// Flag which is set on ChannelFunded and FundingSent indicating remote side is considered
/// "disconnected" and no updates are allowed until after we've done a channel_reestablish
/// dance.
PeerDisconnected = (1 << 7),
/// Flag which implies that we have sent a commitment_signed but are awaiting the responding
/// revoke_and_ack message. During this time period, we can't generate new commitment_signed
/// messages as then we will be unable to determine which HTLCs they included in their
/// revoke_and_ack implicit ACK, so instead we have to hold them away temporarily to be sent
/// later.
/// Flag is set on ChannelFunded.
AwaitingRemoteRevoke = (1 << 7),
AwaitingRemoteRevoke = (1 << 8),
/// Flag which is set on ChannelFunded or FundingSent after receiving a shutdown message from
/// the remote end. If set, they may not add any new HTLCs to the channel, and we are expected
/// to respond with our own shutdown message when possible.
RemoteShutdownSent = (1 << 8),
RemoteShutdownSent = (1 << 9),
/// Flag which is set on ChannelFunded or FundingSent after sending a shutdown message. At this
/// point, we may not add any new HTLCs to the channel.
/// TODO: Investigate some kind of timeout mechanism by which point the remote end must provide
/// us their shutdown.
LocalShutdownSent = (1 << 9),
LocalShutdownSent = (1 << 10),
/// We've successfully negotiated a closing_signed dance. At this point ChannelManager is about
/// to drop us, but we store this anyway.
ShutdownComplete = (1 << 10),
ShutdownComplete = 2048,
}
const BOTH_SIDES_SHUTDOWN_MASK: u32 = (ChannelState::LocalShutdownSent as u32 | ChannelState::RemoteShutdownSent as u32);
@ -1061,7 +1072,7 @@ impl Channel {
// can claim it even if the channel hits the chain before we see their next commitment.
self.channel_monitor.provide_payment_preimage(&payment_hash_calc, &payment_preimage_arg);
if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == (ChannelState::AwaitingRemoteRevoke as u32) {
if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32)) != 0 {
for pending_update in self.holding_cell_htlc_updates.iter() {
match pending_update {
&HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
@ -1137,7 +1148,7 @@ impl Channel {
}
// Now update local state:
if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == (ChannelState::AwaitingRemoteRevoke as u32) {
if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32)) != 0 {
for pending_update in self.holding_cell_htlc_updates.iter() {
match pending_update {
&HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
@ -1354,12 +1365,23 @@ impl Channel {
}
pub fn funding_locked(&mut self, msg: &msgs::FundingLocked) -> Result<(), HandleError> {
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent funding_locked when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent funding_locked when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
let non_shutdown_state = self.channel_state & (!BOTH_SIDES_SHUTDOWN_MASK);
if non_shutdown_state == ChannelState::FundingSent as u32 {
self.channel_state |= ChannelState::TheirFundingLocked as u32;
} else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurFundingLocked as u32) {
self.channel_state = ChannelState::ChannelFunded as u32 | (self.channel_state & BOTH_SIDES_SHUTDOWN_MASK);
self.channel_update_count += 1;
} else if self.channel_state & (ChannelState::ChannelFunded as u32) != 0 &&
self.cur_local_commitment_transaction_number == (1 << 48) - 2 &&
self.cur_remote_commitment_transaction_number == (1 << 48) - 2 {
if self.their_cur_commitment_point != Some(msg.next_per_commitment_point) {
return Err(HandleError{err: "Peer sent a reconnect funding_locked with a different point", action: None});
}
// They probably disconnected/reconnected and re-sent the funding_locked, which is required
return Ok(());
} else {
return Err(HandleError{err: "Peer sent a funding_locked at a strange time", action: None});
}
@ -1411,6 +1433,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32 | ChannelState::RemoteShutdownSent as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent update_add_htlc when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_add_htlc when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
if msg.amount_msat > self.channel_value_satoshis * 1000 {
return Err(HandleError{err: "Remote side tried to send more than the total value of the channel", action: None});
}
@ -1489,6 +1514,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent update_fulfill_htlc when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_fulfill_htlc when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
let mut sha = Sha256::new();
sha.input(&msg.payment_preimage);
@ -1502,6 +1530,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent update_fail_htlc when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_fail_htlc when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
self.mark_outbound_htlc_removed(msg.htlc_id, None, Some(fail_reason))
}
@ -1510,6 +1541,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got add HTLC message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent update_fail_malformed_htlc when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_fail_malformed_htlc when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
self.mark_outbound_htlc_removed(msg.htlc_id, None, Some(fail_reason))
}
@ -1518,6 +1552,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got commitment signed message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent commitment_signed when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent commitment_signed when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
let funding_script = self.get_funding_redeemscript();
@ -1680,6 +1717,9 @@ impl Channel {
if (self.channel_state & (ChannelState::ChannelFunded as u32)) != (ChannelState::ChannelFunded as u32) {
return Err(HandleError{err: "Got revoke/ACK message when channel was not in an operational state", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent revoke_and_ack when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent revoke_and_ack when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
if let Some(their_prev_commitment_point) = self.their_prev_commitment_point {
if PublicKey::from_secret_key(&self.secp_ctx, &secp_call!(SecretKey::from_slice(&self.secp_ctx, &msg.per_commitment_secret), "Peer provided an invalid per_commitment_secret", self.channel_id())) != their_prev_commitment_point {
return Err(HandleError{err: "Got a revoke commitment secret which didn't correspond to their current pubkey", action: None});
@ -1789,6 +1829,7 @@ impl Channel {
pub fn remove_uncommitted_htlcs(&mut self) -> Vec<(HTLCSource, [u8; 32])> {
let mut outbound_drops = Vec::new();
assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
if self.channel_state < ChannelState::FundingSent as u32 {
self.channel_state = ChannelState::ShutdownComplete as u32;
return outbound_drops;
@ -1845,6 +1886,9 @@ impl Channel {
if self.channel_outbound {
return Err(HandleError{err: "Non-funding remote tried to update channel fee", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent update_fee when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent update_fee when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
Channel::check_remote_fee(fee_estimator, msg.feerate_per_kw)?;
self.channel_update_count += 1;
self.feerate_per_kw = msg.feerate_per_kw as u64;
@ -1852,6 +1896,9 @@ impl Channel {
}
pub fn shutdown(&mut self, fee_estimator: &FeeEstimator, msg: &msgs::Shutdown) -> Result<(Option<msgs::Shutdown>, Option<msgs::ClosingSigned>, Vec<(HTLCSource, [u8; 32])>), HandleError> {
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent shutdown when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent shutdown when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
if self.channel_state < ChannelState::FundingSent as u32 {
self.channel_state = ChannelState::ShutdownComplete as u32;
self.channel_update_count += 1;
@ -1952,6 +1999,9 @@ impl Channel {
if self.channel_state & BOTH_SIDES_SHUTDOWN_MASK != BOTH_SIDES_SHUTDOWN_MASK {
return Err(HandleError{err: "Remote end sent us a closing_signed before both sides provided a shutdown", action: None});
}
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Peer sent closing_signed when we needed a channel_reestablish", action: Some(msgs::ErrorAction::SendErrorMessage{msg: msgs::ErrorMessage{data: "Peer sent closing_signed when we needed a channel_reestablish".to_string(), channel_id: msg.channel_id}})});
}
if !self.pending_inbound_htlcs.is_empty() || !self.pending_outbound_htlcs.is_empty() {
return Err(HandleError{err: "Remote end sent us a closing_signed while there were still pending HTLCs", action: None});
}
@ -2128,7 +2178,7 @@ impl Channel {
/// is_usable() and considers things like the channel being temporarily disabled.
/// Allowed in any state (including after shutdown)
pub fn is_live(&self) -> bool {
self.is_usable()
self.is_usable() && (self.channel_state & (ChannelState::PeerDisconnected as u32) == 0)
}
/// Returns true if funding_created was sent/received.
@ -2428,6 +2478,16 @@ impl Channel {
return Err(HandleError{err: "Cannot send less than their minimum HTLC value", action: None});
}
if (self.channel_state & (ChannelState::PeerDisconnected as u32)) == (ChannelState::PeerDisconnected as u32) {
// Note that this should never really happen, if we're !is_live() on receipt of an
// incoming HTLC for relay will result in us rejecting the HTLC and we won't allow
// the user to send directly into a !is_live() channel. However, if we
// disconnected during the time the previous hop was doing the commitment dance we may
// end up getting here after the forwarding delay. In any case, returning an
// IgnoreError will get ChannelManager to do the right thing and fail backwards now.
return Err(HandleError{err: "Cannot send an HTLC while disconnected", action: Some(ErrorAction::IgnoreError)});
}
let (_, outbound_htlc_count, htlc_outbound_value_msat, htlc_inbound_value_msat) = self.get_pending_htlc_stats(false);
if outbound_htlc_count + 1 > self.their_max_accepted_htlcs as u32 {
return Err(HandleError{err: "Cannot push more than their max accepted HTLCs", action: None});
@ -2492,6 +2552,9 @@ impl Channel {
if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32)) == (ChannelState::AwaitingRemoteRevoke as u32) {
panic!("Cannot create commitment tx until remote revokes their previous commitment");
}
if (self.channel_state & (ChannelState::PeerDisconnected as u32)) == (ChannelState::PeerDisconnected as u32) {
panic!("Cannot create commitment tx while disconnected, as send_htlc will have returned an Err so a send_commitment precondition has been violated");
}
let mut have_updates = false; // TODO initialize with "have we sent a fee update?"
for htlc in self.pending_outbound_htlcs.iter() {
if htlc.state == OutboundHTLCState::LocalAnnounced {
@ -2585,6 +2648,9 @@ impl Channel {
return Err(HandleError{err: "Shutdown already in progress", action: None});
}
assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0);
if self.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
return Err(HandleError{err: "Cannot begin shutdown while peer is disconnected, maybe force-close instead?", action: None});
}
let our_closing_script = self.get_closing_scriptpubkey();