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