nim-libp2p/libp2p/connmanager.nim

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## Nim-LibP2P
## Copyright (c) 2020 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import std/[options, tables, sequtils, sets]
import chronos, chronicles, metrics
import peerinfo,
stream/connection,
muxers/muxer
declareGauge(libp2p_peers, "total connected peers")
const MaxConnectionsPerPeer = 5
type
TooManyConnections* = object of CatchableError
MuxerHolder = object
muxer: Muxer
handle: Future[void]
ConnManager* = ref object of RootObj
# NOTE: don't change to PeerInfo here
# the reference semantics on the PeerInfo
# object itself make it succeptible to
# copies and mangling by unrelated code.
conns: Table[PeerID, HashSet[Connection]]
muxed: Table[Connection, MuxerHolder]
maxConns: int
proc newTooManyConnections(): ref TooManyConnections {.inline.} =
result = newException(TooManyConnections, "too many connections for peer")
proc init*(C: type ConnManager,
maxConnsPerPeer: int = MaxConnectionsPerPeer): ConnManager =
C(maxConns: maxConnsPerPeer,
conns: initTable[PeerID, HashSet[Connection]](),
muxed: initTable[Connection, MuxerHolder]())
proc contains*(c: ConnManager, conn: Connection): bool =
## checks if a connection is being tracked by the
## connection manager
##
if isNil(conn):
return
if isNil(conn.peerInfo):
return
return conn in c.conns[conn.peerInfo.peerId]
proc contains*(c: ConnManager, peerId: PeerID): bool =
peerId in c.conns
proc contains*(c: ConnManager, muxer: Muxer): bool =
## checks if a muxer is being tracked by the connection
## manager
##
if isNil(muxer):
return
let conn = muxer.connection
if conn notin c:
return
if conn notin c.muxed:
return
return muxer == c.muxed[conn].muxer
proc closeMuxerHolder(muxerHolder: MuxerHolder) {.async.} =
trace "cleaning up muxer for peer"
await muxerHolder.muxer.close()
if not(isNil(muxerHolder.handle)):
await muxerHolder.handle # TODO noraises?
proc delConn(c: ConnManager, conn: Connection) =
let peerId = conn.peerInfo.peerId
if peerId in c.conns:
c.conns[peerId].excl(conn)
if c.conns[peerId].len == 0:
c.conns.del(peerId)
libp2p_peers.set(c.conns.len.int64)
proc cleanupConn(c: ConnManager, conn: Connection) {.async.} =
## clean connection's resources such as muxers and streams
if isNil(conn):
return
if isNil(conn.peerInfo):
return
# Remove connection from all tables without async breaks
var muxer = some(MuxerHolder())
if not c.muxed.pop(conn, muxer.get()):
muxer = none(MuxerHolder)
delConn(c, conn)
try:
if muxer.isSome:
await closeMuxerHolder(muxer.get())
finally:
await conn.close()
trace "connection cleaned up", conn
proc onClose(c: ConnManager, conn: Connection) {.async.} =
## connection close even handler
##
## triggers the connections resource cleanup
##
try:
await conn.join()
trace "triggering connection cleanup", conn
await c.cleanupConn(conn)
except CancelledError:
# This is top-level procedure which will work as separate task, so it
# do not need to propogate CancelledError.
trace "Unexpected cancellation in connection manager's cleanup"
except CatchableError as exc:
trace "Unexpected exception in connection manager's cleanup",
errMsg = exc.msg
proc selectConn*(c: ConnManager,
peerId: PeerID,
dir: Direction): Connection =
## Select a connection for the provided peer and direction
##
let conns = toSeq(
c.conns.getOrDefault(peerId))
.filterIt( it.dir == dir )
if conns.len > 0:
return conns[0]
proc selectConn*(c: ConnManager, peerId: PeerID): Connection =
## Select a connection for the provided giving priority
## to outgoing connections
##
var conn = c.selectConn(peerId, Direction.Out)
if isNil(conn):
conn = c.selectConn(peerId, Direction.In)
if isNil(conn):
trace "connection not found", peerId
return conn
proc selectMuxer*(c: ConnManager, conn: Connection): Muxer =
## select the muxer for the provided connection
##
if isNil(conn):
return
if conn in c.muxed:
return c.muxed[conn].muxer
else:
debug "no muxer for connection", conn
proc storeConn*(c: ConnManager, conn: Connection) =
## store a connection
##
if isNil(conn):
raise newException(CatchableError, "connection cannot be nil")
if isNil(conn.peerInfo):
raise newException(CatchableError, "empty peer info")
let peerId = conn.peerInfo.peerId
if c.conns.getOrDefault(peerId).len > c.maxConns:
trace "too many connections", peer = $peerId,
conns = c.conns.getOrDefault(peerId).len
raise newTooManyConnections()
if peerId notin c.conns:
c.conns[peerId] = initHashSet[Connection]()
c.conns[peerId].incl(conn)
# Launch on close listener
# All the errors are handled inside `onClose()` procedure.
asyncSpawn c.onClose(conn)
libp2p_peers.set(c.conns.len.int64)
trace "stored connection", connections = c.conns.len, conn
proc storeOutgoing*(c: ConnManager, conn: Connection) =
conn.dir = Direction.Out
c.storeConn(conn)
proc storeIncoming*(c: ConnManager, conn: Connection) =
conn.dir = Direction.In
c.storeConn(conn)
proc storeMuxer*(c: ConnManager,
muxer: Muxer,
handle: Future[void] = nil) =
## store the connection and muxer
##
if isNil(muxer):
raise newException(CatchableError, "muxer cannot be nil")
if isNil(muxer.connection):
raise newException(CatchableError, "muxer's connection cannot be nil")
c.muxed[muxer.connection] = MuxerHolder(
muxer: muxer,
handle: handle)
trace "stored muxer", connections = c.conns.len, muxer
proc getMuxedStream*(c: ConnManager,
peerId: PeerID,
dir: Direction): Future[Connection] {.async, gcsafe.} =
## get a muxed stream for the provided peer
## with the given direction
##
let muxer = c.selectMuxer(c.selectConn(peerId, dir))
if not(isNil(muxer)):
return await muxer.newStream()
proc getMuxedStream*(c: ConnManager,
peerId: PeerID): Future[Connection] {.async, gcsafe.} =
## get a muxed stream for the passed peer from any connection
##
let muxer = c.selectMuxer(c.selectConn(peerId))
if not(isNil(muxer)):
return await muxer.newStream()
proc getMuxedStream*(c: ConnManager,
conn: Connection): Future[Connection] {.async, gcsafe.} =
## get a muxed stream for the passed connection
##
let muxer = c.selectMuxer(conn)
if not(isNil(muxer)):
return await muxer.newStream()
proc dropPeer*(c: ConnManager, peerId: PeerID) {.async.} =
## drop connections and cleanup resources for peer
##
let conns = c.conns.getOrDefault(peerId)
for conn in conns:
delConn(c, conn)
var muxers: seq[MuxerHolder]
for conn in conns:
if conn in c.muxed:
muxers.add c.muxed[conn]
c.muxed.del(conn)
for muxer in muxers:
await closeMuxerHolder(muxer)
for conn in conns:
await conn.close()
proc close*(c: ConnManager) {.async.} =
## cleanup resources for the connection
## manager
##
let conns = c.conns
c.conns.clear()
let muxed = c.muxed
c.muxed.clear()
for _, muxer in muxed:
await closeMuxerHolder(muxer)
for _, conns2 in conns:
for conn in conns2:
await conn.close()