In this commit, we modify the existing message sending functionality
within the fundingmanager. Due to each mesage send requiring to hold the
server's lock to retrieve the peer, we might run into a case where the
lock is held for a larger than usual amount of time and would therefore
block on sending the message within the fundingmanager. We remedy this
by taking a similar approach to some recent changes within the gossiper.
We now keep track of each peer within the internal fundingmanager
messages and send messages directly to them.
In this commit, we add a timeout within the writeMessage method when we go to write to the socket. We do this as otherwise, if the other peer is blocked for some reason, we'll never actually unblock ourselves, which may cause issues in other sub-systems waiting on this write call. For now, we use a value of 10 seconds, and will adjust in the future if we deem this time period too short.
In this commit, we move the block height dependency from the links in
the switch to the switch itself. This is possible due to a recent change
on the links no longer depending on the block height to update their
commitment fees.
We'll now only have the switch be alerted of new blocks coming in and
links will retrieve the height from it atomically.
In this commit, we modify the behavior of links updating their
commitment fees. Rather than attempting to update the commitment fee for
each link every time a new block comes in, we'll use a timer with a
random interval between 10 and 60 minutes for each link to determine
when to update their corresponding commitment fee. This prevents us from
oscillating the fee rate for our various commitment transactions.
In this commit we fix an existing bug which could cause internal state
inconsistency between then switch, funding manager, and the peer. Before
this commit, we would _always_ add a new channel to the channelManager.
However, due to recent logic, it may be the case that this isn't the
channel that will ultimately reside in the link. As a result, we would
be unable to process incoming FundingLocked messages properly, as we
would mutate the incorrect channel in memory.
We remedy this by moving the inserting of the new channel into the
activeChannels map until the end of the loadActiveChannels method, where
we know that this will be the link that persists.
In this commit, we fix a recently introduced bug. The issue is that
while we're failing the link, the peer we're attempting to force close
on may disconnect. As a result, if the peerTerminationWatcher exits
before we can add to the wait group (it's waiting on that), then we'll
run into a panic as we're attempting to increment the wait group while
another goroutine is calling wait.
The fix is to first check that the server isn't shutting down, and then
use the server's wait group rather than the peer to synchronize
goroutines.
Fixes#1285.
This commit makes the peer aware of the LinkFailureErrors that can
happen during link operation, and making it start a goroutine to
properly remove the link and force close the channel.
This commit attempts to resolve some potential deadlock
scenarios during a peer disconnect.
Currently, writeMessage returns a nil error when disconnecting.
This should have minimal impact on the writeHanlder, as the
subsequent loop selects on the quit chan, and will cause it to
exit. However, if this happens when sending the init message,
the Start() method will attempt to proceed even though the peer
has been disconnected.
In addition, this commit changes the behavior of synchronous
write errors, by using a non-blocking select. Though unlikely,
this prevents any cases where multiple errors are returned, and
the errors are not being pulled from the other side of the errChan.
This removes any naked sends on the errChan from stalling the peer's
shutdown.
In this commit, we ensure that any time we send a TempChannelFailure
that's destined for a multi-hop source sender, then we'll always package
the latest channel update along with it.
In this commit, we fix a bug that could at times cause a deadlock when a
peer is attempting to disconnect. The issue was that when a peer goes to
disconnect, it needs to stop any active msgStream instances. The Stop()
method of the msgStream would block until an atomic variable was set to
indicate that the stream had fully exited. However, in the case that we
disconnected lower in the msgConsumer loop, we would never set the
streamShutdown variable, meaning that msgStream.Stop() would never
unblock.
The fix for this is simple: set the streamShutdown variable within the
quit case of the second select statement in the msgConsumer goroutine.
In this commit, we might a very small change to the way writing messages
works in the peer, which should have large implications w.r.t reducing
memory usage amongst chatty nodes.
When profiling the heap on one of my nodes earlier, I noticed this
fragment:
```
Showing top 20 nodes out of 68
flat flat% sum% cum cum%
0 0% 0% 75.53MB 54.61% main.(*peer).writeHandler
75.53MB 54.61% 54.61% 75.53MB 54.61% main.(*peer).writeMessage
```
Which points to an inefficiency with the way we handle allocations when
writing new messages, drilling down further we see:
```
(pprof) list writeMessage
Total: 138.31MB
ROUTINE ======================== main.(*peer).writeMessage in /root/go/src/github.com/lightningnetwork/lnd/peer.go
75.53MB 75.53MB (flat, cum) 54.61% of Total
. . 1104: p.logWireMessage(msg, false)
. . 1105:
. . 1106: // As the Lightning wire protocol is fully message oriented, we only
. . 1107: // allows one wire message per outer encapsulated crypto message. So
. . 1108: // we'll create a temporary buffer to write the message directly to.
75.53MB 75.53MB 1109: var msgPayload [lnwire.MaxMessagePayload]byte
. . 1110: b := bytes.NewBuffer(msgPayload[0:0:len(msgPayload)])
. . 1111:
. . 1112: // With the temp buffer created and sliced properly (length zero, full
. . 1113: // capacity), we'll now encode the message directly into this buffer.
. . 1114: n, err := lnwire.WriteMessage(b, msg, 0)
(pprof) list writeHandler
Total: 138.31MB
ROUTINE ======================== main.(*peer).writeHandler in /root/go/src/github.com/lightningnetwork/lnd/peer.go
0 75.53MB (flat, cum) 54.61% of Total
. . 1148:
. . 1149: // Write out the message to the socket, closing the
. . 1150: // 'sentChan' if it's non-nil, The 'sentChan' allows
. . 1151: // callers to optionally synchronize sends with the
. . 1152: // writeHandler.
. 75.53MB 1153: err := p.writeMessage(outMsg.msg)
. . 1154: if outMsg.errChan != nil {
. . 1155: outMsg.errChan <- err
. . 1156: }
. . 1157:
. . 1158: if err != nil {
```
Ah hah! We create a _new_ buffer each time we want to write a message
out. This is unnecessary and _very_ wasteful (as seen by the profile).
The fix is simple: re-use a buffer unique to each peer when writing out
messages. Since we know what the max message size is, we just allocate
one of these 65KB buffers for each peer, and keep it around until the
peer is removed.
In this commit, we follow up to the prior commit by ensuring we won't
accept a co-op close request for a chennel with active HTLCs. When
creating a chanCloser for the first time, we'll check the set of HTLC's
and reject a request (by sending a wire error) if the target channel
still as active HTLC's.
In this commit, we fix a minor deviation in our implementation from the
specification. Before if we encountered an unknown error type, we would
disconnect the peer. Instead, we’ll now just continue along parsing the
remainder of the messages. This was flared up recently by some
c-lightning related incompatibilities that emerged on main net.
In this commit, we fix a goroutine leak that could occur if while we
were loading an error occurred in any of the steps after we created the
channel object, but before it was actually loaded in to the script. If
an error occurs at any step, we ensure that we’ll stop toe channel.
Otherwise, the sigPool goroutines would still be lingering and never be
stopped.
This commit adds a set used to track channels we consider failed. This
is done to ensure we don't end up in a connect/disconnect loop when we
attempt to re-sync the channel state of a failed channel with a peer.
In this commit, we remove the DecodeHopIterator method from the
ChannelLinkConfig struct. We do this as we no longer use this method,
since we only ever use the DecodeHopIterators method now.
In this commit, we modify the msgStream struct to ensure that it has a
cap at which it’ll continue to buffer messages. Currently we have two
msgStream structs per peer: the first for the discovery messages, and
the second for any messages that modify channel state. Due to
inefficiencies in the current protocol for reconciling graph state upon
connection (just dump the entire damn thing), when a node first starts
up, this can lead to very high memory usage as all peers will
concurrently send their initial message dump which can be in the
thousands of messages on testate.
Our fix is simple: make the message stream into a _bounded_ message
stream. The newMsgStream function now has a new argument: bufSize.
Internally, we’ll take this bufSize and create more or less an internal
semaphore for the producer. Each time the producer gets a new message,
it’ll try and read an item from the channel. If the queue still has
size, then this will succeed immediately. If not, then we’ll block
until the consumer actually finishes processing a message and then
signals by sending a new item into the channel.
We choose an initial value of 1000. This was chosen as there’s already
a max limit of outstanding adds on the commitment, and a value of 1000
should allow any incoming messages to be safely flushed and processed
by the gossiper.
