420 lines
14 KiB
Nim
420 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 tables, sequtils, options, strformat, sets
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import chronos, chronicles
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import connection,
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transports/transport,
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multistream,
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protocols/protocol,
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protocols/secure/secure,
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protocols/secure/plaintext, # for plain text
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peerinfo,
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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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#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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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*: MultistreamSelect
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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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dialedPubSubPeers: HashSet[string]
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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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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): Future[PeerInfo] {.async, gcsafe.} =
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## identify the connection
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if not isNil(conn.peerInfo):
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result = conn.peerInfo
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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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if info.pubKey.isNone and isNil(result):
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raise newException(CatchableError,
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"no public key provided and no existing peer identity found")
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if info.pubKey.isSome:
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result = PeerInfo.init(info.pubKey.get())
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trace "identify: identified remote peer", peer = result.id
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if info.addrs.len > 0:
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result.addrs = info.addrs
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if info.protos.len > 0:
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result.protocols = info.protos
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except IdentityInvalidMsgError as exc:
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error "identify: invalid message", msg = exc.msg
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except IdentityNoMatchError as exc:
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error "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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## mux incoming connection
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trace "muxing connection"
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let muxers = toSeq(s.muxers.keys)
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if muxers.len == 0:
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warn "no muxers registered, skipping upgrade flow"
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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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# create new muxer for connection
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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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# new stream for identify
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var 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 do (udata: pointer = nil):
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trace "muxer handler completed for peer",
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peer = conn.peerInfo.id
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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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conn.peerInfo = await s.identify(stream)
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await stream.close() # close identify stream
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trace "connection's peerInfo", peerInfo = $conn.peerInfo
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# store it in muxed connections if we have a peer for it
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if not isNil(conn.peerInfo):
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trace "adding muxer for peer", peer = conn.peerInfo.id
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s.muxed[conn.peerInfo.id] = muxer
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proc cleanupConn(s: Switch, conn: Connection) {.async, gcsafe.} =
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if not isNil(conn.peerInfo):
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let id = conn.peerInfo.id
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trace "cleaning up connection for peer", peerId = id
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if id in s.muxed:
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await s.muxed[id].close()
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s.muxed.del(id)
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if id in s.connections:
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if not s.connections[id].closed:
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await s.connections[id].close()
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s.connections.del(id)
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s.dialedPubSubPeers.excl(id)
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# TODO: Investigate cleanupConn() always called twice for one peer.
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if not(conn.peerInfo.isClosed()):
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conn.peerInfo.close()
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proc disconnect*(s: Switch, peer: PeerInfo) {.async, gcsafe.} =
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let conn = s.connections.getOrDefault(peer.id)
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if not isNil(conn):
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await s.cleanupConn(conn)
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proc getMuxedStream(s: Switch, peerInfo: PeerInfo): Future[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 peerInfo.id in s.muxed:
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trace "connection is muxed, setting up a stream"
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let muxer = s.muxed[peerInfo.id]
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let conn = await muxer.newStream()
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result = conn
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proc upgradeOutgoing(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
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trace "handling connection", conn = $conn
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result = conn
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# don't mux/secure twise
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if conn.peerInfo.id in s.muxed:
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return
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result = await s.secure(result) # secure the connection
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if isNil(result):
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return
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await s.mux(result) # mux it if possible
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s.connections[conn.peerInfo.id] = result
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proc upgradeIncoming(s: Switch, conn: Connection) {.async, gcsafe.} =
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trace "upgrading incoming connection", conn = $conn
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let ms = newMultistream()
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# secure incoming connections
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proc securedHandler (conn: Connection,
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proto: string)
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{.async, gcsafe, closure.} =
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trace "Securing connection"
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let secure = s.secureManagers[proto]
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let sconn = await secure.secure(conn)
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if not isNil(sconn):
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# add the muxer
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for muxer in s.muxers.values:
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ms.addHandler(muxer.codec, muxer)
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# handle subsequent requests
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await ms.handle(sconn)
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if (await ms.select(conn)): # just handshake
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# add the secure handlers
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for k in s.secureManagers.keys:
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ms.addHandler(k, securedHandler)
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# handle secured connections
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await ms.handle(conn)
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proc subscribeToPeer(s: Switch, peerInfo: PeerInfo) {.async, gcsafe.}
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proc internalConnect(s: Switch,
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peer: PeerInfo): Future[Connection] {.async.} =
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let id = peer.id
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trace "Dialing peer", peer = id
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var conn = s.connections.getOrDefault(id)
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if conn.isNil or conn.closed:
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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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trace "Dialing address", address = $a
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try:
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conn = await t.dial(a)
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except CatchableError as exc:
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trace "couldn't dial peer, transport failed", exc = exc.msg, address = a
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continue
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# make sure to assign the peer to the connection
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conn.peerInfo = peer
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conn = await s.upgradeOutgoing(conn)
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if isNil(conn):
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continue
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conn.closeEvent.wait()
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.addCallback do (udata: pointer):
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asyncCheck s.cleanupConn(conn)
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break
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else:
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trace "Reusing existing connection"
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if not isNil(conn):
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await s.subscribeToPeer(peer)
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result = conn
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proc connect*(s: Switch, peer: PeerInfo) {.async.} =
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var conn = await s.internalConnect(peer)
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if isNil(conn):
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raise newException(CatchableError, "Unable to connect to peer")
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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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var conn = await s.internalConnect(peer)
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if isNil(conn):
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raise newException(CatchableError, "Unable to establish outgoing link")
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if conn.closed:
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raise newException(CatchableError, "Connection dead on arrival")
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result = conn
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let stream = await s.getMuxedStream(peer)
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if not isNil(stream):
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trace "Connection is muxed, return muxed stream"
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result = stream
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trace "Attempting to select remote", proto = proto
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if not await s.ms.select(result, proto):
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warn "Unable to select sub-protocol", proto = proto
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raise newException(CatchableError, &"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 start*(s: Switch): Future[seq[Future[void]]] {.async, gcsafe.} =
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trace "starting switch"
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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 CatchableError as exc:
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trace "Exception occurred in Switch.start", exc = exc.msg
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finally:
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if not isNil(conn) and not conn.closed:
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await conn.close()
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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 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 = await t.listen(a, handle)
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s.peerInfo.addrs[i] = t.ma # update peer's address
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startFuts.add(server)
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if s.pubSub.isSome:
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await s.pubSub.get().start()
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result = 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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if s.pubSub.isSome:
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await s.pubSub.get().stop()
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await allFutures(toSeq(s.connections.values).mapIt(s.cleanupConn(it)))
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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 and peerInfo.id notin s.dialedPubSubPeers:
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try:
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s.dialedPubSubPeers.incl(peerInfo.id)
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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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except CatchableError as exc:
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warn "unable to initiate pubsub", exc = exc.msg
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finally:
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s.dialedPubSubPeers.excl(peerInfo.id)
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proc subscribe*(s: Switch, topic: string,
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handler: TopicHandler): Future[void] =
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## subscribe to a pubsub topic
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if s.pubSub.isNone:
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var retFuture = newFuture[void]("Switch.subscribe")
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retFuture.fail(newNoPubSubException())
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return retFuture
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result = s.pubSub.get().subscribe(topic, handler)
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proc unsubscribe*(s: Switch, topics: seq[TopicPair]): Future[void] =
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## unsubscribe from topics
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if s.pubSub.isNone:
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var retFuture = newFuture[void]("Switch.unsubscribe")
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retFuture.fail(newNoPubSubException())
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return retFuture
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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] =
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# pubslish to pubsub topic
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if s.pubSub.isNone:
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var retFuture = newFuture[void]("Switch.publish")
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retFuture.fail(newNoPubSubException())
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return retFuture
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result = s.pubSub.get().publish(topic, data)
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proc addValidator*(s: Switch,
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topics: varargs[string],
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hook: ValidatorHandler) =
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# add validator
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if s.pubSub.isNone:
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raise newNoPubSubException()
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s.pubSub.get().addValidator(topics, hook)
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proc removeValidator*(s: Switch,
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topics: varargs[string],
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hook: ValidatorHandler) =
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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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s.pubSub.get().removeValidator(topics, hook)
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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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result.dialedPubSubPeers = initHashSet[string]()
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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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trace "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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trace "got new muxer"
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let stream = await muxer.newStream()
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muxer.connection.peerInfo = await s.identify(stream)
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await stream.close()
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for k in secureManagers.keys:
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trace "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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warn "no secure managers, falling back to plain 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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