nim-libp2p/libp2p/switch.nim

219 lines
7.5 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2018 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, # for plain text
peerinfo,
multiaddress,
protocols/identify,
muxers/muxer,
peer
type
Switch* = ref object of RootObj
peerInfo*: PeerInfo
connections*: TableRef[string, Connection]
muxed*: TableRef[string, Muxer]
transports*: seq[Transport]
protocols*: seq[LPProtocol]
muxers*: Table[string, MuxerProvider]
ms*: MultisteamSelect
identity*: Identify
streamHandler*: StreamHandler
secureManagers*: seq[Secure]
proc secure(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
## secure the incoming connection
# plaintext for now, doesn't do anything
let managers = s.secureManagers.mapIt(it.codec).deduplicate()
if managers.len == 0:
raise newException(CatchableError, "No secure managers registered!")
if (await s.ms.select(conn, s.secureManagers.mapIt(it.codec))).len == 0:
raise newException(CatchableError, "Unable to negotiate a secure channel!")
var n = await s.secureManagers[0].secure(conn)
result = conn
proc identify(s: Switch, conn: Connection) {.async, gcsafe.} =
## identify the connection
# s.peerInfo.protocols = await s.ms.list(conn) # update protos before engagin in identify
try:
if (await s.ms.select(conn, s.identity.codec)):
let info = await s.identity.identify(conn, conn.peerInfo)
let id = if conn.peerInfo.isSome:
conn.peerInfo.get().peerId.pretty
else:
""
if id.len > 0 and s.connections.contains(id):
let connection = s.connections[id]
var peerInfo = conn.peerInfo.get()
peerInfo.peerId = PeerID.init(info.pubKey) # we might not have a peerId at all
peerInfo.addrs = info.addrs
peerInfo.protocols = info.protos
debug "identify: identified remote peer ", peer = peerInfo.peerId.pretty
except IdentityInvalidMsgError as exc:
debug "identify: invalid message", msg = exc.msg
except IdentityNoMatchError as exc:
debug "identify: peer's public keys don't match ", msg = exc.msg
proc mux(s: Switch, conn: Connection): Future[void] {.async, gcsafe.} =
## mux incoming connection
let muxers = toSeq(s.muxers.keys)
let muxerName = await s.ms.select(conn, muxers)
if muxerName.len == 0 or muxerName == "na":
return
let muxer = s.muxers[muxerName].newMuxer(conn)
# install stream handler
muxer.streamHandler = s.streamHandler
# do identify first, so that we have a
# PeerInfo in case we didn't before
let stream = await muxer.newStream()
let handlerFut = muxer.handle()
# add muxer handler cleanup proc
handlerFut.addCallback(
proc(udata: pointer = nil) {.gcsafe.} =
if handlerFut.finished:
debug "mux: Muxer handler completed for peer ", peer = conn.peerInfo.get().peerId.pretty
)
await s.identify(stream)
await stream.close() # close idenity stream
# 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.isSome:
s.muxed[conn.peerInfo.get().peerId.pretty] = muxer
proc handleConn(s: Switch, conn: Connection): Future[Connection] {.async, gcsafe.} =
result = conn
## perform upgrade flow
if result.peerInfo.isSome:
let id = result.peerInfo.get().peerId.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 cleanupConn(s: Switch, conn: Connection) {.async, gcsafe.} =
if conn.peerInfo.isSome:
let id = conn.peerInfo.get().peerId.pretty
if s.muxed.contains(id):
await s.muxed[id].close
if s.connections.contains(id):
await s.connections[id].close()
proc dial*(s: Switch,
peer: PeerInfo,
proto: string = ""):
Future[Connection] {.async.} =
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)
result.peerInfo = some(peer)
result = await s.handleConn(result)
# if there is a muxer for the connection
# use it instead to create a muxed stream
if s.muxed.contains(peer.peerId.pretty):
result = await s.muxed[peer.peerId.pretty].newStream()
debug "dial: attempting to select remote ", proto = proto
if not (await s.ms.select(result, proto)):
debug "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) {.async.} =
proc handle(conn: Connection): Future[void] {.async, closure, gcsafe.} =
try:
if (await s.ms.select(conn)):
await s.ms.handle(conn) # handle incoming connection
except:
await s.cleanupConn(conn)
for t in s.transports: # for each transport
for a in s.peerInfo.addrs:
if t.handles(a): # check if it handles the multiaddr
await t.listen(a, handle) # listen for incoming connections
proc stop*(s: Switch) {.async.} =
await allFutures(s.transports.mapIt(it.close()))
proc newSwitch*(peerInfo: PeerInfo,
transports: seq[Transport],
identity: Identify,
muxers: Table[string, MuxerProvider],
secureManagers: seq[Secure] = @[]): Switch =
new result
result.peerInfo = peerInfo
result.ms = newMultistream()
result.transports = transports
result.connections = newTable[string, Connection]()
result.muxed = newTable[string, Muxer]()
result.identity = identity
result.muxers = muxers
let s = result # can't capture result
result.streamHandler = proc(stream: Connection) {.async, gcsafe.} =
# TODO: figure out proper way of handling this.
# Perhaps it's ok to discard this Future and handle
# errors elsewere?
await s.ms.handle(stream) # handle incoming connection
result.mount(identity)
for key, val in muxers:
val.streamHandler = result.streamHandler
result.mount(val)
for s in secureManagers:
debug "adding secure manager ", codec = s.codec
result.secureManagers.add(s)
result.mount(s)
if result.secureManagers.len == 0:
# use plain text if no secure managers are provided
let manager = Secure(newPlainText())
result.mount(manager)
result.secureManagers.add(manager)
result.secureManagers = result.secureManagers.deduplicate()