352 lines
10 KiB
Nim
352 lines
10 KiB
Nim
# Nim-LibP2P
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# Copyright (c) 2023 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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import stew/results
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import pkg/[chronos, chronicles, metrics]
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import
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dial,
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peerid,
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peerinfo,
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peerstore,
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multicodec,
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muxers/muxer,
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multistream,
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connmanager,
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stream/connection,
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transports/transport,
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nameresolving/nameresolver,
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upgrademngrs/upgrade,
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errors
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export dial, errors, results
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logScope:
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topics = "libp2p dialer"
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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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type
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DialFailedError* = object of LPError
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Dialer* = ref object of Dial
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localPeerId*: PeerId
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connManager: ConnManager
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dialLock: Table[PeerId, AsyncLock]
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transports: seq[Transport]
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peerStore: PeerStore
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nameResolver: NameResolver
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proc dialAndUpgrade(
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self: Dialer,
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peerId: Opt[PeerId],
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hostname: string,
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address: MultiAddress,
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dir = Direction.Out,
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): Future[Muxer] {.async.} =
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for transport in self.transports: # for each transport
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if transport.handles(address): # check if it can dial it
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trace "Dialing address", address, peerId = peerId.get(default(PeerId)), hostname
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let dialed =
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try:
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libp2p_total_dial_attempts.inc()
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await transport.dial(hostname, address, peerId)
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except CancelledError as exc:
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trace "Dialing canceled", err = exc.msg, peerId = peerId.get(default(PeerId))
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raise exc
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except CatchableError as exc:
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debug "Dialing failed", err = exc.msg, peerId = peerId.get(default(PeerId))
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libp2p_failed_dials.inc()
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return nil # Try the next address
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libp2p_successful_dials.inc()
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let mux =
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try:
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# This is for the very specific case of a simultaneous dial during DCUtR. In this case, both sides will have
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# an Outbound direction at the transport level. Therefore we update the DCUtR initiator transport direction to Inbound.
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# The if below is more general and might handle other use cases in the future.
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if dialed.dir != dir:
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dialed.dir = dir
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await transport.upgrade(dialed, peerId)
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except CancelledError as exc:
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await dialed.close()
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raise exc
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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 "Connection upgrade failed",
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err = exc.msg, peerId = peerId.get(default(PeerId))
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if dialed.dir == Direction.Out:
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libp2p_failed_upgrades_outgoing.inc()
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else:
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libp2p_failed_upgrades_incoming.inc()
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# Try other address
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return nil
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doAssert not isNil(mux), "connection died after upgrade " & $dialed.dir
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debug "Dial successful", peerId = mux.connection.peerId
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return mux
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return nil
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proc expandDnsAddr(
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self: Dialer, peerId: Opt[PeerId], address: MultiAddress
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): Future[seq[(MultiAddress, Opt[PeerId])]] {.async.} =
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if not DNSADDR.matchPartial(address):
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return @[(address, peerId)]
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if isNil(self.nameResolver):
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info "Can't resolve DNSADDR without NameResolver", ma = address
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return @[]
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let
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toResolve =
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if peerId.isSome:
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address & MultiAddress.init(multiCodec("p2p"), peerId.tryGet()).tryGet()
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else:
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address
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resolved = await self.nameResolver.resolveDnsAddr(toResolve)
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for resolvedAddress in resolved:
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let lastPart = resolvedAddress[^1].tryGet()
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if lastPart.protoCode == Result[MultiCodec, string].ok(multiCodec("p2p")):
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let
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peerIdBytes = lastPart.protoArgument().tryGet()
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addrPeerId = PeerId.init(peerIdBytes).tryGet()
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result.add((resolvedAddress[0 ..^ 2].tryGet(), Opt.some(addrPeerId)))
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else:
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result.add((resolvedAddress, peerId))
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proc dialAndUpgrade(
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self: Dialer, peerId: Opt[PeerId], addrs: seq[MultiAddress], dir = Direction.Out
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): Future[Muxer] {.async.} =
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debug "Dialing peer", peerId = peerId.get(default(PeerId)), addrs
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for rawAddress in addrs:
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# resolve potential dnsaddr
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let addresses = await self.expandDnsAddr(peerId, rawAddress)
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for (expandedAddress, addrPeerId) in addresses:
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# DNS resolution
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let
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hostname = expandedAddress.getHostname()
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resolvedAddresses =
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if isNil(self.nameResolver):
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@[expandedAddress]
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else:
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await self.nameResolver.resolveMAddress(expandedAddress)
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for resolvedAddress in resolvedAddresses:
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result = await self.dialAndUpgrade(addrPeerId, hostname, resolvedAddress, dir)
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if not isNil(result):
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return result
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proc tryReusingConnection(self: Dialer, peerId: PeerId): Opt[Muxer] =
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let muxer = self.connManager.selectMuxer(peerId)
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if muxer == nil:
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return Opt.none(Muxer)
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trace "Reusing existing connection", muxer, direction = $muxer.connection.dir
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return Opt.some(muxer)
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proc internalConnect(
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self: Dialer,
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peerId: Opt[PeerId],
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addrs: seq[MultiAddress],
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forceDial: bool,
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reuseConnection = true,
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dir = Direction.Out,
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): Future[Muxer] {.async.} =
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if Opt.some(self.localPeerId) == 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 = self.dialLock.mgetOrPut(peerId.get(default(PeerId)), newAsyncLock())
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try:
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await lock.acquire()
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if reuseConnection:
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peerId.withValue(peerId):
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self.tryReusingConnection(peerId).withValue(mux):
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return mux
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let slot = self.connManager.getOutgoingSlot(forceDial)
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let muxed =
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try:
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await self.dialAndUpgrade(peerId, addrs, dir)
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except CatchableError as exc:
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slot.release()
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raise exc
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slot.trackMuxer(muxed)
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if isNil(muxed): # None of the addresses connected
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raise newException(DialFailedError, "Unable to establish outgoing link")
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try:
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self.connManager.storeMuxer(muxed)
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await self.peerStore.identify(muxed)
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await self.connManager.triggerPeerEvents(
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muxed.connection.peerId,
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PeerEvent(kind: PeerEventKind.Identified, initiator: true),
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)
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except CatchableError as exc:
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trace "Failed to finish outgoung upgrade", err = exc.msg
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await muxed.close()
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raise exc
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return muxed
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finally:
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if lock.locked():
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lock.release()
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method connect*(
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self: Dialer,
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peerId: PeerId,
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addrs: seq[MultiAddress],
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forceDial = false,
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reuseConnection = true,
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dir = Direction.Out,
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) {.async.} =
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## connect remote peer without negotiating
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## a protocol
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##
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if self.connManager.connCount(peerId) > 0 and reuseConnection:
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return
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discard
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await self.internalConnect(Opt.some(peerId), addrs, forceDial, reuseConnection, dir)
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method connect*(
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self: Dialer, address: MultiAddress, allowUnknownPeerId = false
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): Future[PeerId] {.async.} =
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## Connects to a peer and retrieve its PeerId
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parseFullAddress(address).toOpt().withValue(fullAddress):
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return (
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await self.internalConnect(Opt.some(fullAddress[0]), @[fullAddress[1]], false)
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).connection.peerId
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if allowUnknownPeerId == false:
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raise newException(
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DialFailedError, "Address without PeerID and unknown peer id disabled!"
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)
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return
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(await self.internalConnect(Opt.none(PeerId), @[address], false)).connection.peerId
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proc negotiateStream(
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self: Dialer, conn: Connection, protos: seq[string]
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): Future[Connection] {.async.} =
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trace "Negotiating stream", conn, protos
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let selected = await MultistreamSelect.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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method tryDial*(
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self: Dialer, peerId: PeerId, addrs: seq[MultiAddress]
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): Future[Opt[MultiAddress]] {.async.} =
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## Create a protocol stream in order to check
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## if a connection is possible.
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## Doesn't use the Connection Manager to save it.
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##
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trace "Check if it can dial", peerId, addrs
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try:
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let mux = await self.dialAndUpgrade(Opt.some(peerId), addrs)
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if mux.isNil():
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raise newException(DialFailedError, "No valid multiaddress")
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await mux.close()
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return mux.connection.observedAddr
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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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raise newException(DialFailedError, exc.msg)
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method dial*(
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self: Dialer, peerId: PeerId, protos: seq[string]
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): Future[Connection] {.async.} =
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## create a protocol stream over an
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## existing connection
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##
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trace "Dialing (existing)", peerId, protos
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let stream = await self.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 self.negotiateStream(stream, protos)
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method dial*(
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self: Dialer,
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peerId: PeerId,
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addrs: seq[MultiAddress],
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protos: seq[string],
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forceDial = false,
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): Future[Connection] {.async.} =
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## create a protocol stream and establish
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## a connection if one doesn't exist already
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##
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var
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conn: Muxer
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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 self.internalConnect(Opt.some(peerId), addrs, forceDial)
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trace "Opening stream", conn
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stream = await self.connManager.getStream(conn)
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if isNil(stream):
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raise newException(DialFailedError, "Couldn't get muxed stream")
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return await self.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, err = exc.msg
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await cleanup()
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raise exc
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method addTransport*(self: Dialer, t: Transport) =
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self.transports &= t
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proc new*(
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T: type Dialer,
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localPeerId: PeerId,
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connManager: ConnManager,
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peerStore: PeerStore,
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transports: seq[Transport],
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nameResolver: NameResolver = nil,
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): Dialer =
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T(
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localPeerId: localPeerId,
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connManager: connManager,
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transports: transports,
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peerStore: peerStore,
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nameResolver: nameResolver,
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)
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