mirror of https://github.com/status-im/nim-eth.git
271 lines
10 KiB
Nim
271 lines
10 KiB
Nim
# Copyright (c) 2021 Status Research & Development GmbH
|
|
# Licensed and distributed under either of
|
|
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
|
|
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
|
|
# at your option. This file may not be copied, modified, or distributed except according to those terms.
|
|
|
|
{.push raises: [Defect].}
|
|
|
|
import
|
|
std/[tables, options, sugar],
|
|
chronos, bearssl, chronicles,
|
|
../keys,
|
|
./utp_socket,
|
|
./packets
|
|
|
|
logScope:
|
|
topics = "utp_router"
|
|
|
|
export utp_socket
|
|
|
|
type
|
|
# New remote client connection callback
|
|
# ``server`` - UtpProtocol object.
|
|
# ``client`` - accepted client utp socket.
|
|
AcceptConnectionCallback*[A] = proc(server: UtpRouter[A],
|
|
client: UtpSocket[A]): Future[void] {.gcsafe, raises: [Defect].}
|
|
|
|
# Callback to act as firewall for incoming peers. Should return true if peer
|
|
# is allowed to connect.
|
|
AllowConnectionCallback*[A] = proc(r: UtpRouter[A], remoteAddress: A,
|
|
connectionId: uint16): bool {.gcsafe, raises: [Defect], noSideEffect.}
|
|
|
|
# Object responsible for creating and maintaining table of utp sockets.
|
|
# Caller should use `processIncomingBytes` proc to feed it with incoming byte
|
|
# packets. Based on this input, proper utp sockets will be created, closed,
|
|
# or will receive data.
|
|
UtpRouter*[A] = ref object
|
|
sockets: Table[UtpSocketKey[A], UtpSocket[A]]
|
|
socketConfig: SocketConfig
|
|
acceptConnection: AcceptConnectionCallback[A]
|
|
closed: bool
|
|
sendCb*: SendCallback[A]
|
|
allowConnection*: AllowConnectionCallback[A]
|
|
rng*: ref BrHmacDrbgContext
|
|
|
|
const
|
|
# Maximal number of tries to generate unique socket while establishing
|
|
# outgoing connection.
|
|
maxSocketGenerationTries = 1000
|
|
|
|
# This should probably be in standard lib, it allows lazy composition of options
|
|
# i.e one can write: O1 orElse O2 orElse O3, and chain will be evaluated to
|
|
# first option which isSome()
|
|
template orElse[A](a: Option[A], b: Option[A]): Option[A] =
|
|
if (a.isSome()):
|
|
a
|
|
else:
|
|
b
|
|
|
|
proc getUtpSocket[A](s: UtpRouter[A], k: UtpSocketKey[A]): Option[UtpSocket[A]] =
|
|
let s = s.sockets.getOrDefault(k)
|
|
if s == nil:
|
|
none[UtpSocket[A]]()
|
|
else:
|
|
some(s)
|
|
|
|
proc deRegisterUtpSocket[A](s: UtpRouter[A], socket: UtpSocket[A]) =
|
|
s.sockets.del(socket.socketKey)
|
|
|
|
iterator allSockets[A](s: UtpRouter[A]): UtpSocket[A] =
|
|
for socket in s.sockets.values():
|
|
yield socket
|
|
|
|
proc len*[A](s: UtpRouter[A]): int =
|
|
## returns number of active sockets
|
|
len(s.sockets)
|
|
|
|
proc registerUtpSocket[A](p: UtpRouter, s: UtpSocket[A]) =
|
|
## Register socket, overwriting already existing one
|
|
p.sockets[s.socketKey] = s
|
|
# Install deregister handler, so when socket gets closed, in will be promptly
|
|
# removed from open sockets table
|
|
s.registerCloseCallback(proc () = p.deRegisterUtpSocket(s))
|
|
|
|
proc registerIfAbsent[A](p: UtpRouter, s: UtpSocket[A]): bool =
|
|
## Registers socket only if it's not already existing in the active sockets
|
|
## table. Returns true if socket has been succesfuly registered.
|
|
if p.sockets.hasKey(s.socketKey):
|
|
false
|
|
else:
|
|
p.registerUtpSocket(s)
|
|
true
|
|
|
|
proc new*[A](
|
|
T: type UtpRouter[A],
|
|
acceptConnectionCb: AcceptConnectionCallback[A],
|
|
allowConnectionCb: AllowConnectionCallback[A],
|
|
socketConfig: SocketConfig = SocketConfig.init(),
|
|
rng = newRng()): UtpRouter[A] =
|
|
doAssert(not(isNil(acceptConnectionCb)))
|
|
UtpRouter[A](
|
|
sockets: initTable[UtpSocketKey[A], UtpSocket[A]](),
|
|
acceptConnection: acceptConnectionCb,
|
|
allowConnection: allowConnectionCb,
|
|
socketConfig: socketConfig,
|
|
rng: rng
|
|
)
|
|
|
|
proc new*[A](
|
|
T: type UtpRouter[A],
|
|
acceptConnectionCb: AcceptConnectionCallback[A],
|
|
socketConfig: SocketConfig = SocketConfig.init(),
|
|
rng = newRng()): UtpRouter[A] =
|
|
UtpRouter[A].new(acceptConnectionCb, nil, socketConfig, rng)
|
|
|
|
# There are different possiblites how connection was established, and we need to
|
|
# check every case
|
|
proc getSocketOnReset[A](r: UtpRouter[A], sender: A, id: uint16): Option[UtpSocket[A]] =
|
|
# id is our recv id
|
|
let recvKey = UtpSocketKey[A].init(sender, id)
|
|
|
|
# id is our send id, and we did nitiate the connection, our recv id is id - 1
|
|
let sendInitKey = UtpSocketKey[A].init(sender, id - 1)
|
|
|
|
# id is our send id, and we did not initiate the connection, so our recv id is id + 1
|
|
let sendNoInitKey = UtpSocketKey[A].init(sender, id + 1)
|
|
|
|
r.getUtpSocket(recvKey)
|
|
.orElse(r.getUtpSocket(sendInitKey).filter(s => s.connectionIdSnd == id))
|
|
.orElse(r.getUtpSocket(sendNoInitKey).filter(s => s.connectionIdSnd == id))
|
|
|
|
proc shouldAllowConnection[A](r: UtpRouter[A], remoteAddress: A, connectionId: uint16): bool =
|
|
if r.allowConnection == nil:
|
|
# if the callback is not configured it means all incoming connections are allowed
|
|
true
|
|
else:
|
|
r.allowConnection(r, remoteAddress, connectionId)
|
|
|
|
proc processPacket[A](r: UtpRouter[A], p: Packet, sender: A) {.async.}=
|
|
notice "Received packet ", packet = p
|
|
|
|
case p.header.pType
|
|
of ST_RESET:
|
|
let maybeSocket = r.getSocketOnReset(sender, p.header.connectionId)
|
|
if maybeSocket.isSome():
|
|
notice "Received rst packet on known connection closing"
|
|
let socket = maybeSocket.unsafeGet()
|
|
# reference implementation acutally changes the socket state to reset state unless
|
|
# user explicitly closed socket before. The only difference between reset and destroy
|
|
# state is that socket in destroy state is ultimatly deleted from active connection
|
|
# list but socket in reset state lingers there until user of library closes it
|
|
# explictly.
|
|
socket.destroy()
|
|
else:
|
|
notice "Received rst packet for not known connection"
|
|
of ST_SYN:
|
|
# Syn packet are special, and we need to add 1 to header connectionId
|
|
let socketKey = UtpSocketKey[A].init(sender, p.header.connectionId + 1)
|
|
let maybeSocket = r.getUtpSocket(socketKey)
|
|
if (maybeSocket.isSome()):
|
|
notice "Ignoring SYN for already existing connection"
|
|
else:
|
|
if (r.shouldAllowConnection(sender, p.header.connectionId)):
|
|
notice "Received SYN for not known connection. Initiating incoming connection"
|
|
# Initial ackNr is set to incoming packer seqNr
|
|
let incomingSocket = newIncomingSocket[A](sender, r.sendCb, r.socketConfig ,p.header.connectionId, p.header.seqNr, r.rng[])
|
|
r.registerUtpSocket(incomingSocket)
|
|
await incomingSocket.startIncomingSocket()
|
|
# Based on configuration, socket is passed to upper layer either in SynRecv
|
|
# or Connected state
|
|
asyncSpawn r.acceptConnection(r, incomingSocket)
|
|
else:
|
|
notice "Connection declined"
|
|
else:
|
|
let socketKey = UtpSocketKey[A].init(sender, p.header.connectionId)
|
|
let maybeSocket = r.getUtpSocket(socketKey)
|
|
if (maybeSocket.isSome()):
|
|
let socket = maybeSocket.unsafeGet()
|
|
await socket.processPacket(p)
|
|
else:
|
|
# TODO add keeping track of recently send reset packets and do not send reset
|
|
# to peers which we recently send reset to.
|
|
notice "Recevied FIN/DATA/ACK on not known socket sending reset"
|
|
let rstPacket = resetPacket(randUint16(r.rng[]), p.header.connectionId, p.header.seqNr)
|
|
await r.sendCb(sender, encodePacket(rstPacket))
|
|
|
|
proc processIncomingBytes*[A](r: UtpRouter[A], bytes: seq[byte], sender: A) {.async.} =
|
|
if (not r.closed):
|
|
let dec = decodePacket(bytes)
|
|
if (dec.isOk()):
|
|
await processPacket[A](r, dec.get(), sender)
|
|
else:
|
|
warn "failed to decode packet from address", address = sender
|
|
|
|
proc generateNewUniqueSocket[A](r: UtpRouter[A], address: A): Option[UtpSocket[A]] =
|
|
## Tries to generate unique socket, gives up after maxSocketGenerationTries tries
|
|
var tryCount = 0
|
|
|
|
while tryCount < maxSocketGenerationTries:
|
|
let rcvId = randUint16(r.rng[])
|
|
let socket = newOutgoingSocket[A](address, r.sendCb, r.socketConfig, rcvId, r.rng[])
|
|
|
|
if r.registerIfAbsent(socket):
|
|
return some(socket)
|
|
|
|
inc tryCount
|
|
|
|
return none[UtpSocket[A]]()
|
|
|
|
proc connect[A](s: UtpSocket[A]): Future[ConnectionResult[A]] {.async.}=
|
|
let startFut = s.startOutgoingSocket()
|
|
|
|
startFut.cancelCallback = proc(udata: pointer) {.gcsafe.} =
|
|
# if for some reason future will be cancelled, destory socket to clear it from
|
|
# active socket list
|
|
s.destroy()
|
|
|
|
try:
|
|
await startFut
|
|
return ok(s)
|
|
except ConnectionError:
|
|
s.destroy()
|
|
return err(OutgoingConnectionError(kind: ConnectionTimedOut))
|
|
except CatchableError as e:
|
|
s.destroy()
|
|
# this may only happen if user provided callback will for some reason fail
|
|
return err(OutgoingConnectionError(kind: ErrorWhileSendingSyn, error: e))
|
|
|
|
# Connect to provided address
|
|
# Reference implementation: https://github.com/bittorrent/libutp/blob/master/utp_internal.cpp#L2732
|
|
proc connectTo*[A](r: UtpRouter[A], address: A): Future[ConnectionResult[A]] {.async.} =
|
|
let maybeSocket = r.generateNewUniqueSocket(address)
|
|
|
|
if (maybeSocket.isNone()):
|
|
return err(OutgoingConnectionError(kind: SocketAlreadyExists))
|
|
else:
|
|
let socket = maybeSocket.unsafeGet()
|
|
return await socket.connect()
|
|
|
|
# Connect to provided address with provided connection id, if socket with this id
|
|
# and address already exsits return error
|
|
proc connectTo*[A](r: UtpRouter[A], address: A, connectionId: uint16): Future[ConnectionResult[A]] {.async.} =
|
|
let socket = newOutgoingSocket[A](address, r.sendCb, r.socketConfig, connectionId, r.rng[])
|
|
|
|
if (r.registerIfAbsent(socket)):
|
|
return await socket.connect()
|
|
else:
|
|
return err(OutgoingConnectionError(kind: SocketAlreadyExists))
|
|
|
|
proc shutdown*[A](r: UtpRouter[A]) =
|
|
# stop processing any new packets and close all sockets in background without
|
|
# notifing remote peers
|
|
r.closed = true
|
|
for s in r.allSockets():
|
|
s.destroy()
|
|
|
|
proc shutdownWait*[A](r: UtpRouter[A]) {.async.} =
|
|
var activeSockets: seq[UtpSocket[A]] = @[]
|
|
# stop processing any new packets and close all sockets without
|
|
# notifing remote peers
|
|
r.closed = true
|
|
|
|
# we need to make copy as calling socket.destroyWait() removes socket from the table
|
|
# and iterator throws error. Antother option would be to wait until number of opensockets
|
|
# go to 0
|
|
for s in r.allSockets():
|
|
activeSockets.add(s)
|
|
|
|
for s in activeSockets:
|
|
yield s.destroyWait()
|