295 lines
10 KiB
Nim
295 lines
10 KiB
Nim
## Nim-LibP2P
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## Copyright (c) 2018 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 tables, sequtils, options, strformat
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import chronos, chronicles
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import connection,
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transports/transport,
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stream/lpstream,
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multistream,
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protocols/protocol,
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protocols/secure/secure, # for plain text
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peerinfo,
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multiaddress,
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protocols/identify,
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protocols/pubsub/pubsub,
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muxers/muxer,
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peer
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logScope:
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topic = "Switch"
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type
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NoPubSubException = object of CatchableError
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Switch* = ref object of RootObj
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peerInfo*: PeerInfo
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connections*: Table[string, Connection]
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muxed*: Table[string, Muxer]
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transports*: seq[Transport]
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protocols*: seq[LPProtocol]
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muxers*: Table[string, MuxerProvider]
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ms*: MultisteamSelect
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identity*: Identify
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streamHandler*: StreamHandler
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secureManagers*: Table[string, Secure]
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pubSub*: Option[PubSub]
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proc newNoPubSubException(): ref Exception {.inline.} =
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result = newException(NoPubSubException, "no pubsub provided!")
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proc secure(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
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## secure the incoming connection
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# plaintext for now, doesn't do anything
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let managers = toSeq(s.secureManagers.keys)
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if managers.len == 0:
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raise newException(CatchableError, "No secure managers registered!")
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let manager = await s.ms.select(conn, toSeq(s.secureManagers.values).mapIt(it.codec))
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if manager.len == 0:
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raise newException(CatchableError, "Unable to negotiate a secure channel!")
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result = await s.secureManagers[manager].secure(conn)
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proc identify*(s: Switch, conn: Connection) {.async, gcsafe.} =
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## identify the connection
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# s.peerInfo.protocols = await s.ms.list(conn) # update protos before engagin in identify
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try:
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if (await s.ms.select(conn, s.identity.codec)):
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let info = await s.identity.identify(conn, conn.peerInfo)
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let id = if conn.peerInfo.peerId.isSome:
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conn.peerInfo.peerId.get().pretty
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else:
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""
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if id.len > 0 and s.connections.contains(id):
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let connection = s.connections[id]
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var peerInfo = conn.peerInfo
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if info.pubKey.isSome:
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peerInfo.peerId = some(PeerID.init(info.pubKey.get())) # we might not have a peerId at all
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if info.addrs.len > 0:
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peerInfo.addrs = info.addrs
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if info.protos.len > 0:
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peerInfo.protocols = info.protos
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debug "identify: identified remote peer ", peer = peerInfo.peerId.get().pretty
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except IdentityInvalidMsgError as exc:
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debug "identify: invalid message", msg = exc.msg
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except IdentityNoMatchError as exc:
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debug "identify: peer's public keys don't match ", msg = exc.msg
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proc mux(s: Switch, conn: Connection): Future[void] {.async, gcsafe.} =
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debug "muxing connection"
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## mux incoming connection
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let muxers = toSeq(s.muxers.keys)
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if muxers.len == 0:
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return
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let muxerName = await s.ms.select(conn, muxers)
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if muxerName.len == 0 or muxerName == "na":
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return
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let muxer = s.muxers[muxerName].newMuxer(conn)
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# install stream handler
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muxer.streamHandler = s.streamHandler
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# do identify first, so that we have a
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# PeerInfo in case we didn't before
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let stream = await muxer.newStream()
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let handlerFut = muxer.handle()
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# add muxer handler cleanup proc
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handlerFut.addCallback(
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proc(udata: pointer = nil) {.gcsafe.} =
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debug "mux: Muxer handler completed for peer ",
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peer = conn.peerInfo.peerId.get().pretty
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)
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await s.identify(stream)
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await stream.close() # close idenity stream
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# store it in muxed connections if we have a peer for it
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# TODO: We should make sure that this are cleaned up properly
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# on exit even if there is no peer for it. This shouldn't
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# happen once secio is in place, but still something to keep
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# in mind
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if conn.peerInfo.peerId.isSome:
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s.muxed[conn.peerInfo.peerId.get().pretty] = muxer
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proc upgradeOutgoing(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
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debug "handling connection", conn = conn
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result = conn
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## perform upgrade flow
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if result.peerInfo.peerId.isSome:
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let id = result.peerInfo.peerId.get().pretty
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if s.connections.contains(id):
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# if we already have a connection for this peer,
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# close the incoming connection and return the
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# existing one
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await result.close()
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return s.connections[id]
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s.connections[id] = result
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result = await s.secure(conn) # secure the connection
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await s.mux(result) # mux it if possible
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proc cleanupConn(s: Switch, conn: Connection) {.async, gcsafe.} =
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if conn.peerInfo.peerId.isSome:
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let id = conn.peerInfo.peerId.get().pretty
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if s.muxed.contains(id):
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await s.muxed[id].close
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if s.connections.contains(id):
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await s.connections[id].close()
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proc getMuxedStream(s: Switch, peerInfo: PeerInfo): Future[Option[Connection]] {.async, gcsafe.} =
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# if there is a muxer for the connection
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# use it instead to create a muxed stream
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if s.muxed.contains(peerInfo.peerId.get().pretty):
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let muxer = s.muxed[peerInfo.peerId.get().pretty]
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let conn = await muxer.newStream()
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result = some(conn)
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proc dial*(s: Switch,
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peer: PeerInfo,
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proto: string = ""):
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Future[Connection] {.async.} =
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for t in s.transports: # for each transport
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for a in peer.addrs: # for each address
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if t.handles(a): # check if it can dial it
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result = await t.dial(a)
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# make sure to assign the peer to the connection
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result.peerInfo = peer
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result = await s.upgradeOutgoing(result)
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let stream = await s.getMuxedStream(peer)
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if stream.isSome:
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result = stream.get()
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debug "dial: attempting to select remote ", proto = proto
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if not (await s.ms.select(result, proto)):
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debug "dial: Unable to select protocol: ", proto = proto
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raise newException(CatchableError,
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&"Unable to select protocol: {proto}")
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proc mount*[T: LPProtocol](s: Switch, proto: T) {.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.codec, proto)
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proc upgradeIncoming(s: Switch, conn: Connection) {.async, gcsafe.} =
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let ms = newMultistream()
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if (await ms.select(conn)): # just handshake
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for secure in s.secureManagers.values:
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ms.addHandler(secure.codec, secure)
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await ms.handle(conn)
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for muxer in s.muxers.values:
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ms.addHandler(muxer.codec, muxer)
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await ms.handle(conn)
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proc start*(s: Switch): Future[seq[Future[void]]] {.async, gcsafe.} =
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proc handle(conn: Connection): Future[void] {.async, closure, gcsafe.} =
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try:
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await s.upgradeIncoming(conn) # perform upgrade on incoming connection
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except:
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await s.cleanupConn(conn)
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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 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 = await t.listen(a, handle)
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startFuts.add(server)
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result = startFuts # listen for incoming connections
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proc stop*(s: Switch) {.async.} =
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await allFutures(s.transports.mapIt(it.close()))
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proc subscribeToPeer*(s: Switch, peerInfo: PeerInfo) {.async, gcsafe.} =
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## Subscribe to pub sub peer
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if s.pubSub.isSome:
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let conn = await s.dial(peerInfo, s.pubSub.get().codec)
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await s.pubSub.get().subscribeToPeer(conn)
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proc subscribe*(s: Switch, topic: string, handler: TopicHandler): Future[void] {.gcsafe.} =
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## subscribe to a pubsub topic
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if s.pubSub.isNone:
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raise newNoPubSubException()
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result = s.pubSub.get().subscribe(topic, handler)
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proc unsubscribe*(s: Switch, topics: seq[string]): Future[void] {.gcsafe.} =
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## unsubscribe from topics
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if s.pubSub.isNone:
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raise newNoPubSubException()
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result = s.pubSub.get().unsubscribe(topics)
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proc publish*(s: Switch, topic: string, data: seq[byte]): Future[void] {.gcsafe.} =
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# pubslish to pubsub topic
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if s.pubSub.isNone:
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raise newNoPubSubException()
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result = s.pubSub.get().publish(topic, data)
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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: Table[string, Secure] = initTable[string, Secure](),
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pubSub: Option[PubSub] = none(PubSub)): Switch =
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new result
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result.peerInfo = peerInfo
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result.ms = newMultistream()
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result.transports = transports
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result.connections = initTable[string, Connection]()
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result.muxed = initTable[string, Muxer]()
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result.identity = identity
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result.muxers = muxers
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result.secureManagers = initTable[string, Secure]()
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let s = result # can't capture result
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result.streamHandler = proc(stream: Connection) {.async, gcsafe.} =
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debug "handling connection for", peerInfo = stream.peerInfo
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await s.ms.handle(stream) # handle incoming connection
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result.mount(identity)
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for key, val in muxers:
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val.streamHandler = result.streamHandler
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val.muxerHandler = proc(muxer: Muxer) {.async, gcsafe.} =
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debug "got new muxer"
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let stream = await muxer.newStream()
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await s.identify(stream)
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for k in secureManagers.keys:
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debug "adding secure manager ", codec = secureManagers[k].codec
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result.secureManagers[k] = secureManagers[k]
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if result.secureManagers.len == 0:
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# use plain text if no secure managers are provided
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debug "no secure managers, falling back to palin text", codec = PlainTextCodec
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result.secureManagers[PlainTextCodec] = Secure(newPlainText())
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if pubSub.isSome:
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result.pubSub = pubSub
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result.mount(pubSub.get())
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