nim-libp2p-experimental/libp2p/switch.nim

315 lines
11 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2019 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import tables, sequtils, options, strformat
import chronos, chronicles
import connection,
transports/transport,
stream/lpstream,
multistream,
protocols/protocol,
protocols/secure/secure,
protocols/secure/plaintext, # for plain text
peerinfo,
multiaddress,
protocols/identify,
protocols/pubsub/pubsub,
muxers/muxer,
peer
logScope:
topic = "Switch"
type
NoPubSubException = object of CatchableError
Switch* = ref object of RootObj
peerInfo*: PeerInfo
connections*: Table[string, Connection]
muxed*: Table[string, Muxer]
transports*: seq[Transport]
protocols*: seq[LPProtocol]
muxers*: Table[string, MuxerProvider]
ms*: MultisteamSelect
identity*: Identify
streamHandler*: StreamHandler
secureManagers*: Table[string, Secure]
pubSub*: Option[PubSub]
proc newNoPubSubException(): ref Exception {.inline.} =
result = newException(NoPubSubException, "no pubsub provided!")
proc secure(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
## secure the incoming connection
# plaintext for now, doesn't do anything
let managers = toSeq(s.secureManagers.keys)
if managers.len == 0:
raise newException(CatchableError, "No secure managers registered!")
let manager = await s.ms.select(conn, toSeq(s.secureManagers.values).mapIt(it.codec))
if manager.len == 0:
raise newException(CatchableError, "Unable to negotiate a secure channel!")
result = await s.secureManagers[manager].secure(conn)
proc identify(s: Switch, conn: Connection): Future[PeerInfo] {.async, gcsafe.} =
## identify the connection
try:
if (await s.ms.select(conn, s.identity.codec)):
let info = await s.identity.identify(conn, conn.peerInfo)
if info.pubKey.isSome:
result.peerId = some(PeerID.init(info.pubKey.get())) # we might not have a peerId at all
if info.addrs.len > 0:
result.addrs = info.addrs
if info.protos.len > 0:
result.protocols = info.protos
trace "identify: identified remote peer ", peer = result.peerId.get().pretty
except IdentityInvalidMsgError as exc:
error "identify: invalid message", msg = exc.msg
except IdentityNoMatchError as exc:
error "identify: peer's public keys don't match ", msg = exc.msg
proc mux(s: Switch, conn: Connection): Future[void] {.async, gcsafe.} =
## mux incoming connection
trace "muxing connection"
let muxers = toSeq(s.muxers.keys)
if muxers.len == 0:
warn "no muxers registered, skipping upgrade flow"
return
let muxerName = await s.ms.select(conn, muxers)
if muxerName.len == 0 or muxerName == "na":
return
# create new muxer for connection
let muxer = s.muxers[muxerName].newMuxer(conn)
# install stream handler
muxer.streamHandler = s.streamHandler
# new stream for identify
let stream = await muxer.newStream()
let handlerFut = muxer.handle()
# add muxer handler cleanup proc
handlerFut.addCallback(
proc(udata: pointer = nil) {.gcsafe.} =
trace "mux: Muxer handler completed for peer ",
peer = conn.peerInfo.peerId.get().pretty
)
# do identify first, so that we have a
# PeerInfo in case we didn't before
conn.peerInfo = await s.identify(stream)
await stream.close() # close idenity stream
trace "connection's peerInfo", peerInfo = conn.peerInfo.peerId
# store it in muxed connections if we have a peer for it
# TODO: We should make sure that this are cleaned up properly
# on exit even if there is no peer for it. This shouldn't
# happen once secio is in place, but still something to keep
# in mind
if conn.peerInfo.peerId.isSome:
trace "adding muxer for peer", peer = conn.peerInfo.peerId.get().pretty
s.muxed[conn.peerInfo.peerId.get().pretty] = muxer
proc cleanupConn(s: Switch, conn: Connection) {.async, gcsafe.} =
if conn.peerInfo.peerId.isSome:
let id = conn.peerInfo.peerId.get().pretty
if s.muxed.contains(id):
await s.muxed[id].close
if s.connections.contains(id):
await s.connections[id].close()
proc getMuxedStream(s: Switch, peerInfo: PeerInfo): Future[Option[Connection]] {.async, gcsafe.} =
# if there is a muxer for the connection
# use it instead to create a muxed stream
if s.muxed.contains(peerInfo.peerId.get().pretty):
trace "connection is muxed, retriving muxer and setting up a stream"
let muxer = s.muxed[peerInfo.peerId.get().pretty]
let conn = await muxer.newStream()
result = some(conn)
proc upgradeOutgoing(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
trace "handling connection", conn = conn
result = conn
## perform upgrade flow
if result.peerInfo.peerId.isSome:
let id = result.peerInfo.peerId.get().pretty
if s.connections.contains(id):
# if we already have a connection for this peer,
# close the incoming connection and return the
# existing one
await result.close()
return s.connections[id]
s.connections[id] = result
result = await s.secure(conn) # secure the connection
await s.mux(result) # mux it if possible
proc upgradeIncoming(s: Switch, conn: Connection) {.async, gcsafe.} =
trace "upgrading incoming connection"
let ms = newMultistream()
# secure incoming connections
proc securedHandler (conn: Connection,
proto: string)
{.async, gcsafe, closure.} =
trace "Securing connection"
let secure = s.secureManagers[proto]
let sconn = await secure.secure(conn)
if not isNil(sconn):
# add the muxer
for muxer in s.muxers.values:
ms.addHandler(muxer.codec, muxer)
# handle subsequent requests
await ms.handle(sconn)
if (await ms.select(conn)): # just handshake
# add the secure handlers
for k in s.secureManagers.keys:
ms.addHandler(k, securedHandler)
# handle secured connections
await ms.handle(conn)
proc dial*(s: Switch,
peer: PeerInfo,
proto: string = ""):
Future[Connection] {.async.} =
trace "dialing peer", peer = peer.peerId.get().pretty
for t in s.transports: # for each transport
for a in peer.addrs: # for each address
if t.handles(a): # check if it can dial it
result = await t.dial(a)
# make sure to assign the peer to the connection
result.peerInfo = peer
result = await s.upgradeOutgoing(result)
let stream = await s.getMuxedStream(peer)
if stream.isSome:
trace "connection is muxed, return muxed stream"
result = stream.get()
trace "dial: attempting to select remote ", proto = proto
if not (await s.ms.select(result, proto)):
error "dial: Unable to select protocol: ", proto = proto
raise newException(CatchableError,
&"Unable to select protocol: {proto}")
proc mount*[T: LPProtocol](s: Switch, proto: T) {.gcsafe.} =
if isNil(proto.handler):
raise newException(CatchableError,
"Protocol has to define a handle method or proc")
if proto.codec.len == 0:
raise newException(CatchableError,
"Protocol has to define a codec string")
s.ms.addHandler(proto.codec, proto)
proc start*(s: Switch): Future[seq[Future[void]]] {.async, gcsafe.} =
proc handle(conn: Connection): Future[void] {.async, closure, gcsafe.} =
try:
await s.upgradeIncoming(conn) # perform upgrade on incoming connection
finally:
await s.cleanupConn(conn)
var startFuts: seq[Future[void]]
for t in s.transports: # for each transport
for i, a in s.peerInfo.addrs:
if t.handles(a): # check if it handles the multiaddr
var server = await t.listen(a, handle)
s.peerInfo.addrs[i] = t.ma # update peer's address
startFuts.add(server)
result = startFuts # listen for incoming connections
proc stop*(s: Switch) {.async.} =
await allFutures(toSeq(s.connections.values).mapIt(it.close()))
await allFutures(s.transports.mapIt(it.close()))
proc subscribeToPeer*(s: Switch, peerInfo: PeerInfo) {.async, gcsafe.} =
## Subscribe to pub sub peer
if s.pubSub.isSome:
let conn = await s.dial(peerInfo, s.pubSub.get().codec)
await s.pubSub.get().subscribeToPeer(conn)
proc subscribe*(s: Switch, topic: string, handler: TopicHandler): Future[void] {.gcsafe.} =
## subscribe to a pubsub topic
if s.pubSub.isNone:
raise newNoPubSubException()
result = s.pubSub.get().subscribe(topic, handler)
proc unsubscribe*(s: Switch, topics: seq[TopicPair]): Future[void] {.gcsafe.} =
## unsubscribe from topics
if s.pubSub.isNone:
raise newNoPubSubException()
result = s.pubSub.get().unsubscribe(topics)
proc publish*(s: Switch, topic: string, data: seq[byte]): Future[void] {.gcsafe.} =
# pubslish to pubsub topic
if s.pubSub.isNone:
raise newNoPubSubException()
result = s.pubSub.get().publish(topic, data)
proc newSwitch*(peerInfo: PeerInfo,
transports: seq[Transport],
identity: Identify,
muxers: Table[string, MuxerProvider],
secureManagers: Table[string, Secure] = initTable[string, Secure](),
pubSub: Option[PubSub] = none(PubSub)): Switch =
new result
result.peerInfo = peerInfo
result.ms = newMultistream()
result.transports = transports
result.connections = initTable[string, Connection]()
result.muxed = initTable[string, Muxer]()
result.identity = identity
result.muxers = muxers
result.secureManagers = initTable[string, Secure]()
let s = result # can't capture result
result.streamHandler = proc(stream: Connection) {.async, gcsafe.} =
debug "handling connection for", peerInfo = stream.peerInfo
await s.ms.handle(stream) # handle incoming connection
result.mount(identity)
for key, val in muxers:
val.streamHandler = result.streamHandler
val.muxerHandler = proc(muxer: Muxer) {.async, gcsafe.} =
trace "got new muxer"
let stream = await muxer.newStream()
muxer.connection.peerInfo = await s.identify(stream)
await stream.close()
for k in secureManagers.keys:
trace "adding secure manager ", codec = secureManagers[k].codec
result.secureManagers[k] = secureManagers[k]
if result.secureManagers.len == 0:
# use plain text if no secure managers are provided
warn "no secure managers, falling back to palin text", codec = PlainTextCodec
result.secureManagers[PlainTextCodec] = Secure(newPlainText())
if pubSub.isSome:
result.pubSub = pubSub
result.mount(pubSub.get())