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Utp improvements (#489) 

* Move connection finalization to separate function

* Do not process data unless in correct state
This commit is contained in:
KonradStaniec 2022-03-18 08:13:17 +01:00 committed by GitHub
parent f16f175412
commit 0e20fd6565
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2 changed files with 225 additions and 161 deletions
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328
eth/utp/utp_socket.nim
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@ -1039,6 +1039,25 @@ proc sendAck(socket: UtpSocket) =
socket.sendData(encodePacket(ackPacket))
proc tryfinalizeConnection(socket: UtpSocket, p: Packet) =
# To avoid amplification attacks, server socket is in SynRecv state until
# it receices first data transfer
# https://www.usenix.org/system/files/conference/woot15/woot15-paper-adamsky.pdf
# Socket is in SynRecv state only when recv timeout is configured
if (socket.state == SynRecv and p.header.pType == ST_DATA):
socket.state = Connected
if (socket.state == SynSent and p.header.pType == ST_STATE):
socket.state = Connected
socket.ackNr = p.header.seqNr - 1
debug "Received Syn-Ack finalizing connection",
socketAckNr = socker.ackNr
if (not socket.connectionFuture.finished()):
socket.connectionFuture.complete()
# TODO at socket level we should handle only FIN/DATA/ACK packets. Refactor to make
# it enforcable by type system
proc processPacketInternal(socket: UtpSocket, p: Packet) =
@ -1227,6 +1246,8 @@ proc processPacketInternal(socket: UtpSocket, p: Packet) =
resetZeroWindowTime = socket.zeroWindowTimer,
currentPacketSize = currentPacketSize
socket.tryfinalizeConnection(p)
# socket.curWindowPackets == acks means that this packet acked all remaining packets
# including the sent fin packets
if (socket.finSent and socket.curWindowPackets == acks):
@ -1280,177 +1301,162 @@ proc processPacketInternal(socket: UtpSocket, p: Packet) =
if (p.eack.isSome()):
socket.selectiveAckPackets(pkAckNr, p.eack.unsafeGet(), timestampInfo.moment)
case p.header.pType
of ST_DATA, ST_FIN:
# To avoid amplification attacks, server socket is in SynRecv state until
# it receices first data transfer
# https://www.usenix.org/system/files/conference/woot15/woot15-paper-adamsky.pdf
# Socket is in SynRecv state only when recv timeout is configured
if (socket.state == SynRecv and p.header.pType == ST_DATA):
socket.state = Connected
if p.header.pType == ST_DATA or p.header.pType == ST_FIN:
if socket.state != Connected:
debug "Unexpected packet",
socketState = socket.state,
packetType = p.header.pType
if (p.header.pType == ST_FIN and (not socket.gotFin)):
debug "Received FIN packet",
eofPktNr = pkSeqNr,
curAckNr = socket.ackNr
# we have received user generated packet (DATA or FIN), in not connected
# state. Stop processing it.
return
socket.gotFin = true
socket.eofPktNr = pkSeqNr
if (p.header.pType == ST_FIN and (not socket.gotFin)):
debug "Received FIN packet",
eofPktNr = pkSeqNr,
curAckNr = socket.ackNr
# we got in order packet
if (pastExpected == 0 and (not socket.reachedFin)):
debug "Received in order packet"
let payloadLength = len(p.payload)
if (payloadLength > 0 and (not socket.readShutdown)):
# we need to sum both rcv buffer and reorder buffer
if (uint32(socket.offset) + socket.inBufferBytes + uint32(payloadLength) > socket.socketConfig.optRcvBuffer):
# even though packet is in order and passes all the checks, it would
# overflow our receive buffer, it means that we are receiving data
# faster than we are reading it. Do not ack this packet, and drop received
# data
debug "Recevied packet would overflow receive buffer dropping it",
pkSeqNr = p.header.seqNr,
bytesReceived = payloadLength,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
return
debug "Received data packet",
bytesReceived = payloadLength
# we are getting in order data packet, we can flush data directly to the incoming buffer
# await upload(addr socket.buffer, unsafeAddr p.payload[0], p.payload.len())
moveMem(addr socket.rcvBuffer[socket.offset], unsafeAddr p.payload[0], payloadLength)
socket.offset = socket.offset + payloadLength
# Bytes have been passed to upper layer, we can increase number of last
# acked packet
inc socket.ackNr
# check if the following packets are in reorder buffer
debug "Looking for packets in re-order buffer",
reorderCount = socket.reorderCount
while true:
# We are doing this in reoreder loop, to handle the case when we already received
# fin but there were some gaps before eof
# we have reached remote eof, and should not receive more packets from remote
if ((not socket.reachedFin) and socket.gotFin and socket.eofPktNr == socket.ackNr):
debug "Reached socket EOF"
# In case of reaching eof, it is up to user of library what to to with
# it. With the current implementation, the most apropriate way would be to
# destory it (as with our implementation we know that remote is destroying its acked fin)
# as any other send will either generate timeout, or socket will be forcefully
# closed by reset
socket.reachedFin = true
# this is not necessarily true, but as we have already reached eof we can
# ignore following packets
socket.reorderCount = 0
if socket.reorderCount == 0:
break
let nextPacketNum = socket.ackNr + 1
let maybePacket = socket.inBuffer.get(nextPacketNum)
if maybePacket.isNone():
break
let packet = maybePacket.unsafeGet()
let reorderPacketPayloadLength = len(packet.payload)
if (reorderPacketPayloadLength > 0 and (not socket.readShutdown)):
debug "Got packet from reorder buffer",
packetBytes = len(packet.payload),
packetSeqNr = packet.header.seqNr,
packetAckNr = packet.header.ackNr,
socketSeqNr = socket.seqNr,
socektAckNr = socket.ackNr,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
# Rcv buffer and reorder buffer are sized that it is always possible to
# move data from reorder buffer to rcv buffer without overflow
moveMem(addr socket.rcvBuffer[socket.offset], unsafeAddr packet.payload[0], reorderPacketPayloadLength)
socket.offset = socket.offset + reorderPacketPayloadLength
debug "Deleting packet",
seqNr = nextPacketNum
socket.inBuffer.delete(nextPacketNum)
inc socket.ackNr
dec socket.reorderCount
socket.inBufferBytes = socket.inBufferBytes - uint32(reorderPacketPayloadLength)
debug "Socket state after processing in order packet",
socketKey = socket.socketKey,
socketAckNr = socket.ackNr,
reorderCount = socket.reorderCount,
windowPackets = socket.curWindowPackets
# TODO for now we just schedule concurrent task with ack sending. It may
# need improvement, as with this approach there is no direct control over
# how many concurrent tasks there are and how to cancel them when socket
# is closed
socket.sendAck()
# we got packet out of order
else:
debug "Got out of order packet"
if (socket.gotFin and pkSeqNr > socket.eofPktNr):
debug "Got packet past eof",
pkSeqNr = pkSeqNr,
eofPktNr = socket.eofPktNr
socket.gotFin = true
socket.eofPktNr = pkSeqNr
# we got in order packet
if (pastExpected == 0 and (not socket.reachedFin)):
debug "Received in order packet"
let payloadLength = len(p.payload)
if (payloadLength > 0 and (not socket.readShutdown)):
# we need to sum both rcv buffer and reorder buffer
if (uint32(socket.offset) + socket.inBufferBytes + uint32(payloadLength) > socket.socketConfig.optRcvBuffer):
# even though packet is in order and passes all the checks, it would
# overflow our receive buffer, it means that we are receiving data
# faster than we are reading it. Do not ack this packet, and drop received
# data
debug "Recevied packet would overflow receive buffer dropping it",
pkSeqNr = p.header.seqNr,
bytesReceived = payloadLength,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
return
# growing buffer before checking the packet is already there to avoid
# looking at older packet due to indices wrap aroud
socket.inBuffer.ensureSize(pkSeqNr + 1, pastExpected + 1)
debug "Received data packet",
bytesReceived = payloadLength
# we are getting in order data packet, we can flush data directly to the incoming buffer
# await upload(addr socket.buffer, unsafeAddr p.payload[0], p.payload.len())
moveMem(addr socket.rcvBuffer[socket.offset], unsafeAddr p.payload[0], payloadLength)
socket.offset = socket.offset + payloadLength
# Bytes have been passed to upper layer, we can increase number of last
# acked packet
inc socket.ackNr
if (socket.inBuffer.get(pkSeqNr).isSome()):
debug "Packet with seqNr already received",
seqNr = pkSeqNr
else:
let payloadLength = uint32(len(p.payload))
if (socket.inBufferBytes + payloadLength <= socket.socketConfig.maxSizeOfReorderBuffer and
socket.inBufferBytes + uint32(socket.offset) + payloadLength <= socket.socketConfig.optRcvBuffer):
debug "store packet in reorder buffer",
packetBytes = payloadLength,
packetSeqNr = p.header.seqNr,
packetAckNr = p.header.ackNr,
socketSeqNr = socket.seqNr,
socektAckNr = socket.ackNr,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
# check if the following packets are in reorder buffer
socket.inBuffer.put(pkSeqNr, p)
inc socket.reorderCount
socket.inBufferBytes = socket.inBufferBytes + payloadLength
debug "added out of order packet to reorder buffer",
reorderCount = socket.reorderCount
# we send ack packet, as we reoreder count is > 0, so the eack bitmask will be
# generated
socket.sendAck()
debug "Looking for packets in re-order buffer",
reorderCount = socket.reorderCount
of ST_STATE:
if (socket.state == SynSent and (not socket.connectionFuture.finished())):
socket.state = Connected
# TODO reference implementation sets ackNr (p.header.seqNr - 1), although
# spec mention that it should be equal p.header.seqNr. For now follow the
# reference impl to be compatible with it. Later investigate trin compatibility.
socket.ackNr = p.header.seqNr - 1
# In case of SynSent complate the future as last thing to make sure user of libray will
# receive socket in correct state
socket.connectionFuture.complete()
while true:
# We are doing this in reoreder loop, to handle the case when we already received
# fin but there were some gaps before eof
# we have reached remote eof, and should not receive more packets from remote
if ((not socket.reachedFin) and socket.gotFin and socket.eofPktNr == socket.ackNr):
debug "Reached socket EOF"
# In case of reaching eof, it is up to user of library what to to with
# it. With the current implementation, the most apropriate way would be to
# destory it (as with our implementation we know that remote is destroying its acked fin)
# as any other send will either generate timeout, or socket will be forcefully
# closed by reset
socket.reachedFin = true
# this is not necessarily true, but as we have already reached eof we can
# ignore following packets
socket.reorderCount = 0
of ST_RESET:
debug "Received ST_RESET on known socket, ignoring"
of ST_SYN:
debug "Received ST_SYN on known socket, ignoring"
if socket.reorderCount == 0:
break
let nextPacketNum = socket.ackNr + 1
let maybePacket = socket.inBuffer.get(nextPacketNum)
if maybePacket.isNone():
break
let packet = maybePacket.unsafeGet()
let reorderPacketPayloadLength = len(packet.payload)
if (reorderPacketPayloadLength > 0 and (not socket.readShutdown)):
debug "Got packet from reorder buffer",
packetBytes = len(packet.payload),
packetSeqNr = packet.header.seqNr,
packetAckNr = packet.header.ackNr,
socketSeqNr = socket.seqNr,
socektAckNr = socket.ackNr,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
# Rcv buffer and reorder buffer are sized that it is always possible to
# move data from reorder buffer to rcv buffer without overflow
moveMem(addr socket.rcvBuffer[socket.offset], unsafeAddr packet.payload[0], reorderPacketPayloadLength)
socket.offset = socket.offset + reorderPacketPayloadLength
debug "Deleting packet",
seqNr = nextPacketNum
socket.inBuffer.delete(nextPacketNum)
inc socket.ackNr
dec socket.reorderCount
socket.inBufferBytes = socket.inBufferBytes - uint32(reorderPacketPayloadLength)
debug "Socket state after processing in order packet",
socketKey = socket.socketKey,
socketAckNr = socket.ackNr,
reorderCount = socket.reorderCount,
windowPackets = socket.curWindowPackets
# TODO for now we just schedule concurrent task with ack sending. It may
# need improvement, as with this approach there is no direct control over
# how many concurrent tasks there are and how to cancel them when socket
# is closed
socket.sendAck()
# we got packet out of order
else:
debug "Got out of order packet"
if (socket.gotFin and pkSeqNr > socket.eofPktNr):
debug "Got packet past eof",
pkSeqNr = pkSeqNr,
eofPktNr = socket.eofPktNr
return
# growing buffer before checking the packet is already there to avoid
# looking at older packet due to indices wrap aroud
socket.inBuffer.ensureSize(pkSeqNr + 1, pastExpected + 1)
if (socket.inBuffer.get(pkSeqNr).isSome()):
debug "Packet with seqNr already received",
seqNr = pkSeqNr
else:
let payloadLength = uint32(len(p.payload))
if (socket.inBufferBytes + payloadLength <= socket.socketConfig.maxSizeOfReorderBuffer and
socket.inBufferBytes + uint32(socket.offset) + payloadLength <= socket.socketConfig.optRcvBuffer):
debug "store packet in reorder buffer",
packetBytes = payloadLength,
packetSeqNr = p.header.seqNr,
packetAckNr = p.header.ackNr,
socketSeqNr = socket.seqNr,
socektAckNr = socket.ackNr,
rcvbufferSize = socket.offset,
reorderBufferSize = socket.inBufferBytes
socket.inBuffer.put(pkSeqNr, p)
inc socket.reorderCount
socket.inBufferBytes = socket.inBufferBytes + payloadLength
debug "added out of order packet to reorder buffer",
reorderCount = socket.reorderCount
# we send ack packet, as we reoreder count is > 0, so the eack bitmask will be
# generated
socket.sendAck()
proc processPacket*(socket: UtpSocket, p: Packet): Future[void] =
socket.eventQueue.put(SocketEvent(kind: NewPacket, packet: p))

58
tests/utp/test_utp_socket.nim
View File

@ -1407,3 +1407,61 @@ procSuite "Utp socket unit test":
resent3.header.seqNr == sent3.header.seqNr
await outgoingSocket.destroyWait()
asyncTest "Socket should accept data only in connected state":
let q = newAsyncQueue[Packet]()
let initialRemoteSeq = 10'u16
let cfg = SocketConfig.init()
let remoteReciveBuffer = 1024'u32
let dataDropped = @[1'u8]
let dataRecived = @[2'u8]
let sock1 = newOutgoingSocket[TransportAddress](testAddress, initTestSnd(q), cfg, defaultRcvOutgoingId, rng[])
asyncSpawn sock1.startOutgoingSocket()
let initialPacket = await q.get()
check:
initialPacket.header.pType == ST_SYN
let dpDropped = dataPacket(
initialRemoteSeq,
initialPacket.header.connectionId,
initialPacket.header.seqNr,
testBufferSize,
dataDropped,
0
)
let dpReceived = dataPacket(
initialRemoteSeq,
initialPacket.header.connectionId,
initialPacket.header.seqNr,
testBufferSize,
dataRecived,
0
)
let responseAck =
ackPacket(
initialRemoteSeq,
initialPacket.header.connectionId,
initialPacket.header.seqNr,
remoteReciveBuffer,
0
)
# even though @[1'u8] is received first, it should be dropped as socket is not
# yet in connected state
await sock1.processPacket(dpDropped)
await sock1.processPacket(responseAck)
await sock1.processPacket(dpReceived)
let receivedData = await sock1.read(1)
check:
receivedData == dataRecived
await sock1.destroyWait()