437 lines
14 KiB
Nim
437 lines
14 KiB
Nim
## Nim-LibP2P
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## Copyright (c) 2019 Status Research & Development GmbH
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## Licensed under either of
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## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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import std/[tables,
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sequtils,
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options,
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sets,
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oids,
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sugar,
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math]
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import chronos,
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chronicles,
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metrics
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import stream/connection,
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transports/transport,
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upgrademngrs/[upgrade, muxedupgrade],
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multistream,
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multiaddress,
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protocols/protocol,
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protocols/secure/secure,
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peerinfo,
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protocols/identify,
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muxers/muxer,
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utils/semaphore,
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connmanager,
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peerid,
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errors
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export connmanager, upgrade
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logScope:
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topics = "libp2p switch"
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#TODO: General note - use a finite state machine to manage the different
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# steps of connections establishing and upgrading. This makes everything
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# more robust and less prone to ordering attacks - i.e. muxing can come if
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# and only if the channel has been secured (i.e. if a secure manager has been
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# previously provided)
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declareCounter(libp2p_total_dial_attempts, "total attempted dials")
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declareCounter(libp2p_successful_dials, "dialed successful peers")
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declareCounter(libp2p_failed_dials, "failed dials")
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declareCounter(libp2p_failed_upgrades_incoming, "incoming connections failed upgrades")
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declareCounter(libp2p_failed_upgrades_outgoing, "outgoing connections failed upgrades")
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const
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ConcurrentUpgrades* = 4
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type
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DialFailedError* = object of CatchableError
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Switch* = ref object of RootObj
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peerInfo*: PeerInfo
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connManager*: ConnManager
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transports*: seq[Transport]
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ms*: MultistreamSelect
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dialLock: Table[PeerID, AsyncLock]
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acceptFuts: seq[Future[void]]
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upgrade: Upgrade
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proc addConnEventHandler*(s: Switch,
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handler: ConnEventHandler,
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kind: ConnEventKind) =
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s.connManager.addConnEventHandler(handler, kind)
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proc removeConnEventHandler*(s: Switch,
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handler: ConnEventHandler,
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kind: ConnEventKind) =
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s.connManager.removeConnEventHandler(handler, kind)
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proc addPeerEventHandler*(s: Switch,
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handler: PeerEventHandler,
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kind: PeerEventKind) =
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s.connManager.addPeerEventHandler(handler, kind)
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proc removePeerEventHandler*(s: Switch,
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handler: PeerEventHandler,
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kind: PeerEventKind) =
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s.connManager.removePeerEventHandler(handler, kind)
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proc disconnect*(s: Switch, peerId: PeerID) {.async, gcsafe.}
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proc isConnected*(s: Switch, peerId: PeerID): bool =
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## returns true if the peer has one or more
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## associated connections (sockets)
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##
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peerId in s.connManager
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proc disconnect*(s: Switch, peerId: PeerID): Future[void] {.gcsafe.} =
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s.connManager.dropPeer(peerId)
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proc dialAndUpgrade(s: Switch,
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peerId: PeerID,
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addrs: seq[MultiAddress]):
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Future[Connection] {.async.} =
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debug "Dialing peer", peerId
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# Avoid "cannot be captured as it would violate memory safety" errors in Nim-1.4.x.
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var
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transport: Transport
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address: MultiAddress
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for t in s.transports: # for each transport
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transport = t
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for a in addrs: # for each address
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address = a
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if t.handles(a): # check if it can dial it
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trace "Dialing address", address = $a, peerId
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let dialed = try:
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libp2p_total_dial_attempts.inc()
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# await a connection slot when the total
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# connection count is equal to `maxConns`
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await s.connManager.trackOutgoingConn(
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() => transport.dial(address)
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)
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except TooManyConnectionsError as exc:
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trace "Connection limit reached!"
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raise exc
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except CancelledError as exc:
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debug "Dialing canceled", msg = exc.msg, peerId
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raise exc
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except CatchableError as exc:
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debug "Dialing failed", msg = exc.msg, peerId
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libp2p_failed_dials.inc()
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continue # Try the next address
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# make sure to assign the peer to the connection
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dialed.peerInfo = PeerInfo.init(peerId, addrs)
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libp2p_successful_dials.inc()
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let conn = try:
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await s.upgrade.upgradeOutgoing(dialed)
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except CatchableError as exc:
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# If we failed to establish the connection through one transport,
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# we won't succeeded through another - no use in trying again
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await dialed.close()
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debug "Upgrade failed", msg = exc.msg, peerId
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if exc isnot CancelledError:
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libp2p_failed_upgrades_outgoing.inc()
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raise exc
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doAssert not isNil(conn), "connection died after upgradeOutgoing"
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debug "Dial successful", conn, peerInfo = conn.peerInfo
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return conn
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proc internalConnect(s: Switch,
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peerId: PeerID,
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addrs: seq[MultiAddress]):
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Future[Connection] {.async.} =
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if s.peerInfo.peerId == peerId:
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raise newException(CatchableError, "can't dial self!")
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# Ensure there's only one in-flight attempt per peer
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let lock = s.dialLock.mgetOrPut(peerId, newAsyncLock())
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try:
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await lock.acquire()
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# Check if we have a connection already and try to reuse it
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var conn = s.connManager.selectConn(peerId)
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if conn != nil:
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if conn.atEof or conn.closed:
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# This connection should already have been removed from the connection
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# manager - it's essentially a bug that we end up here - we'll fail
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# for now, hoping that this will clean themselves up later...
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warn "dead connection in connection manager", conn
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await conn.close()
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raise newException(DialFailedError, "Zombie connection encountered")
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trace "Reusing existing connection", conn, direction = $conn.dir
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return conn
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conn = await s.dialAndUpgrade(peerId, addrs)
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if isNil(conn): # None of the addresses connected
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raise newException(DialFailedError, "Unable to establish outgoing link")
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# We already check for this in Connection manager
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# but a disconnect could have happened right after
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# we've added the connection so we check again
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# to prevent races due to that.
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if conn.closed() or conn.atEof():
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# This can happen when the other ends drops us
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# before we get a chance to return the connection
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# back to the dialer.
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trace "Connection dead on arrival", conn
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raise newLPStreamClosedError()
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return conn
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finally:
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if lock.locked():
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lock.release()
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proc connect*(s: Switch, peerId: PeerID, addrs: seq[MultiAddress]) {.async.} =
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## attempt to create establish a connection
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## with a remote peer
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##
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if s.connManager.connCount(peerId) > 0:
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return
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discard await s.internalConnect(peerId, addrs)
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proc negotiateStream(s: Switch, conn: Connection, protos: seq[string]): Future[Connection] {.async.} =
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trace "Negotiating stream", conn, protos
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let selected = await s.ms.select(conn, protos)
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if not protos.contains(selected):
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await conn.closeWithEOF()
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raise newException(DialFailedError, "Unable to select sub-protocol " & $protos)
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return conn
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proc dial*(s: Switch,
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peerId: PeerID,
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protos: seq[string]): Future[Connection] {.async.} =
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trace "Dialing (existing)", peerId, protos
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let stream = await s.connManager.getStream(peerId)
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if stream.isNil:
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raise newException(DialFailedError, "Couldn't get muxed stream")
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return await s.negotiateStream(stream, protos)
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proc dial*(s: Switch,
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peerId: PeerID,
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proto: string): Future[Connection] =
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dial(s, peerId, @[proto])
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proc dial*(s: Switch,
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peerId: PeerID,
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addrs: seq[MultiAddress],
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protos: seq[string]):
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Future[Connection] {.async.} =
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var
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conn: Connection
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stream: Connection
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proc cleanup() {.async.} =
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if not(isNil(stream)):
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await stream.closeWithEOF()
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if not(isNil(conn)):
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await conn.close()
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try:
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trace "Dialing (new)", peerId, protos
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conn = await s.internalConnect(peerId, addrs)
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trace "Opening stream", conn
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stream = await s.connManager.getStream(conn)
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if isNil(stream):
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raise newException(DialFailedError,
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"Couldn't get muxed stream")
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return await s.negotiateStream(stream, protos)
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except CancelledError as exc:
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trace "Dial canceled", conn
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await cleanup()
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raise exc
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except CatchableError as exc:
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debug "Error dialing", conn, msg = exc.msg
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await cleanup()
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raise exc
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proc dial*(s: Switch,
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peerId: PeerID,
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addrs: seq[MultiAddress],
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proto: string):
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Future[Connection] = dial(s, peerId, addrs, @[proto])
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proc mount*[T: LPProtocol](s: Switch, proto: T, matcher: Matcher = nil) {.gcsafe.} =
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if isNil(proto.handler):
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raise newException(CatchableError,
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"Protocol has to define a handle method or proc")
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if proto.codec.len == 0:
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raise newException(CatchableError,
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"Protocol has to define a codec string")
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s.ms.addHandler(proto.codecs, proto, matcher)
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proc upgradeMonitor(conn: Connection, upgrades: AsyncSemaphore) {.async.} =
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## monitor connection for upgrades
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##
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try:
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# Since we don't control the flow of the
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# upgrade, this timeout guarantees that a
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# "hanged" remote doesn't hold the upgrade
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# forever
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await conn.onUpgrade.wait(30.seconds) # wait for connection to be upgraded
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trace "Connection upgrade succeeded"
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except CatchableError as exc:
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libp2p_failed_upgrades_incoming.inc()
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if not isNil(conn):
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await conn.close()
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trace "Exception awaiting connection upgrade", exc = exc.msg, conn
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finally:
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upgrades.release() # don't forget to release the slot!
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proc accept(s: Switch, transport: Transport) {.async.} = # noraises
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## switch accept loop, ran for every transport
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##
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let upgrades = newAsyncSemaphore(ConcurrentUpgrades)
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while transport.running:
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var conn: Connection
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try:
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debug "About to accept incoming connection"
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# remember to always release the slot when
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# the upgrade succeeds or fails, this is
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# currently done by the `upgradeMonitor`
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await upgrades.acquire() # first wait for an upgrade slot to become available
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conn = await s.connManager # next attempt to get an incoming connection
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.trackIncomingConn(
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() => transport.accept()
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)
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if isNil(conn):
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# A nil connection means that we might have hit a
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# file-handle limit (or another non-fatal error),
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# we can get one on the next try, but we should
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# be careful to not end up in a thigh loop that
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# will starve the main event loop, thus we sleep
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# here before retrying.
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trace "Unable to get a connection, sleeping"
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await sleepAsync(100.millis) # TODO: should be configurable?
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upgrades.release()
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continue
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debug "Accepted an incoming connection", conn
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asyncSpawn upgradeMonitor(conn, upgrades)
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asyncSpawn s.upgrade.upgradeIncoming(conn)
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except CancelledError as exc:
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trace "releasing semaphore on cancellation"
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upgrades.release() # always release the slot
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except CatchableError as exc:
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debug "Exception in accept loop, exiting", exc = exc.msg
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upgrades.release() # always release the slot
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if not isNil(conn):
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await conn.close()
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return
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proc start*(s: Switch): Future[seq[Future[void]]] {.async, gcsafe.} =
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trace "starting switch for peer", peerInfo = s.peerInfo
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var startFuts: seq[Future[void]]
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for t in s.transports: # for each transport
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for i, a in s.peerInfo.addrs:
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if t.handles(a): # check if it handles the multiaddr
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var server = t.start(a)
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s.peerInfo.addrs[i] = t.ma # update peer's address
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s.acceptFuts.add(s.accept(t))
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startFuts.add(server)
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debug "Started libp2p node", peer = s.peerInfo
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return startFuts # listen for incoming connections
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proc stop*(s: Switch) {.async.} =
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trace "Stopping switch"
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# close and cleanup all connections
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await s.connManager.close()
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for t in s.transports:
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try:
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await t.stop()
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except CancelledError as exc:
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raise exc
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except CatchableError as exc:
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warn "error cleaning up transports", msg = exc.msg
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try:
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await allFutures(s.acceptFuts)
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.wait(1.seconds)
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except CatchableError as exc:
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trace "Exception while stopping accept loops", exc = exc.msg
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# check that all futures were properly
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# stopped and otherwise cancel them
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for a in s.acceptFuts:
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if not a.finished:
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a.cancel()
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trace "Switch stopped"
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proc newSwitch*(peerInfo: PeerInfo,
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transports: seq[Transport],
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identity: Identify,
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muxers: Table[string, MuxerProvider],
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secureManagers: openarray[Secure] = [],
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maxConnections = MaxConnections,
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maxIn = -1,
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maxOut = -1,
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maxConnsPerPeer = MaxConnectionsPerPeer): Switch =
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if secureManagers.len == 0:
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raise (ref CatchableError)(msg: "Provide at least one secure manager")
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let ms = newMultistream()
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let connManager = ConnManager.init(maxConnsPerPeer, maxConnections, maxIn, maxOut)
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let upgrade = MuxedUpgrade.init(identity, muxers, secureManagers, connManager, ms)
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let switch = Switch(
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peerInfo: peerInfo,
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ms: ms,
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transports: transports,
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connManager: connManager,
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upgrade: upgrade,
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)
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switch.mount(identity)
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return switch
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proc isConnected*(s: Switch, peerInfo: PeerInfo): bool
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{.deprecated: "Use PeerID version".} =
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not isNil(peerInfo) and isConnected(s, peerInfo.peerId)
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proc disconnect*(s: Switch, peerInfo: PeerInfo): Future[void]
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{.deprecated: "Use PeerID version", gcsafe.} =
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disconnect(s, peerInfo.peerId)
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proc connect*(s: Switch, peerInfo: PeerInfo): Future[void]
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{.deprecated: "Use PeerID version".} =
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connect(s, peerInfo.peerId, peerInfo.addrs)
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proc dial*(s: Switch,
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peerInfo: PeerInfo,
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proto: string):
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Future[Connection]
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{.deprecated: "Use PeerID version".} =
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dial(s, peerInfo.peerId, peerInfo.addrs, proto)
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