mirror of https://github.com/status-im/nim-eth.git
Handle packets with selective acks (#451)
* Handle packets with selective acks
This commit is contained in:
KonradStaniec
GitHub
parent
5655bd035c
commit
0cfe7df817
|
|
@ -17,8 +17,10 @@ export results
|
|||
|
||||
const
|
||||
minimalHeaderSize = 20
|
||||
minimalHeaderSizeWithSelectiveAck = 26
|
||||
protocolVersion = 1
|
||||
zeroMoment = Moment.init(0, Nanosecond)
|
||||
acksArrayLength: uint8 = 4
|
||||
|
||||
type
|
||||
PacketType* = enum
|
||||
|
|
@ -46,8 +48,12 @@ type
|
|||
# sequence number the sender of the packet last received in the other direction
|
||||
ackNr*: uint16
|
||||
|
||||
SelectiveAckExtension = object
|
||||
acks: array[acksArrayLength, byte]
|
||||
|
||||
Packet* = object
|
||||
header*: PacketHeaderV1
|
||||
eack*: Option[SelectiveAckExtension]
|
||||
payload*: seq[uint8]
|
||||
|
||||
TimeStampInfo* = object
|
||||
|
|
@ -102,10 +108,22 @@ proc encodeHeaderStream(s: var OutputStream, h: PacketHeaderV1) =
|
|||
# This should not happen in case of in-memory streams
|
||||
raiseAssert e.msg
|
||||
|
||||
proc encodeExtensionStream(s: var OutputStream, e: SelectiveAckExtension) =
|
||||
try:
|
||||
# writing 0 as there is not further extensions after selectiv ack
|
||||
s.write(0'u8)
|
||||
s.write(acksArrayLength)
|
||||
s.write(e.acks)
|
||||
except IOError as e:
|
||||
# This should not happen in case of in-memory streams
|
||||
raiseAssert e.msg
|
||||
|
||||
proc encodePacket*(p: Packet): seq[byte] =
|
||||
var s = memoryOutput().s
|
||||
try:
|
||||
encodeHeaderStream(s, p.header)
|
||||
if (p.eack.isSome()):
|
||||
encodeExtensionStream(s, p.eack.unsafeGet())
|
||||
if (len(p.payload) > 0):
|
||||
s.write(p.payload)
|
||||
s.getOutput()
|
||||
|
|
@ -113,9 +131,9 @@ proc encodePacket*(p: Packet): seq[byte] =
|
|||
# This should not happen in case of in-memory streams
|
||||
raiseAssert e.msg
|
||||
|
||||
# TODO for now we do not handle extensions
|
||||
proc decodePacket*(bytes: openArray[byte]): Result[Packet, string] =
|
||||
if len(bytes) < minimalHeaderSize:
|
||||
let receivedBytesLength = len(bytes)
|
||||
if receivedBytesLength < minimalHeaderSize:
|
||||
return err("invalid header size")
|
||||
|
||||
let version = bytes[0] and 0xf
|
||||
|
|
@ -126,11 +144,16 @@ proc decodePacket*(bytes: openArray[byte]): Result[Packet, string] =
|
|||
if not checkedEnumAssign(kind, (bytes[0] shr 4)):
|
||||
return err("Invalid message type")
|
||||
|
||||
let extensionByte = bytes[1]
|
||||
|
||||
if (not (extensionByte == 0 or extensionByte == 1)):
|
||||
return err("Invalid extension type")
|
||||
|
||||
let header =
|
||||
PacketHeaderV1(
|
||||
pType: kind,
|
||||
version: version,
|
||||
extension: bytes[1],
|
||||
extension: extensionByte,
|
||||
connection_id: fromBytesBE(uint16, bytes.toOpenArray(2, 3)),
|
||||
timestamp: fromBytesBE(uint32, bytes.toOpenArray(4, 7)),
|
||||
timestamp_diff: fromBytesBE(uint32, bytes.toOpenArray(8, 11)),
|
||||
|
|
@ -139,13 +162,43 @@ proc decodePacket*(bytes: openArray[byte]): Result[Packet, string] =
|
|||
ack_nr: fromBytesBE(uint16, bytes.toOpenArray(18, 19)),
|
||||
)
|
||||
|
||||
if extensionByte == 0:
|
||||
# packet without any extensions
|
||||
let payload =
|
||||
if (len(bytes) == 20):
|
||||
if (receivedBytesLength == minimalHeaderSize):
|
||||
@[]
|
||||
else:
|
||||
bytes[20..^1]
|
||||
|
||||
ok(Packet(header: header, payload: payload))
|
||||
return ok(Packet(header: header, eack: none[SelectiveAckExtension](), payload: payload))
|
||||
else:
|
||||
# packet with selective ack extension
|
||||
if (receivedBytesLength < minimalHeaderSizeWithSelectiveAck):
|
||||
return err("Packet too short for selective ack extension")
|
||||
|
||||
let nextExtension = bytes[20]
|
||||
let extLength = bytes[21]
|
||||
|
||||
# As selective ack is only supported extension the byte for nextExtension
|
||||
# must be equal to 0.
|
||||
# As for extLength, specificaiton says that it must be at least 4, and in multiples of 4
|
||||
# but reference implementation always uses 4 bytes bit mask which makes sense
|
||||
# as 4byte bit mask is able to ack 32 packets in the future which is more than enough
|
||||
if (nextExtension != 0 or extLength != 4):
|
||||
return err("Bad format of selective ack extension")
|
||||
|
||||
|
||||
let extension = SelectiveAckExtension(
|
||||
acks: [bytes[22], bytes[23], bytes[24], bytes[25]]
|
||||
)
|
||||
|
||||
let payload =
|
||||
if (receivedBytesLength == minimalHeaderSizeWithSelectiveAck):
|
||||
@[]
|
||||
else:
|
||||
bytes[26..^1]
|
||||
|
||||
return ok(Packet(header: header, eack: some(extension), payload: payload))
|
||||
|
||||
proc modifyTimeStampAndAckNr*(packetBytes: var seq[byte], newTimestamp: uint32, newAckNr: uint16) =
|
||||
## Modifies timestamp and ack nr of already encoded packets. Those fields should be
|
||||
|
|
@ -163,7 +216,6 @@ proc synPacket*(seqNr: uint16, rcvConnectionId: uint16, bufferSize: uint32): Pac
|
|||
let h = PacketHeaderV1(
|
||||
pType: ST_SYN,
|
||||
version: protocolVersion,
|
||||
# TODO for we do not handle extensions
|
||||
extension: 0'u8,
|
||||
connectionId: rcvConnectionId,
|
||||
timestamp: getMonoTimestamp().timestamp,
|
||||
|
|
@ -174,14 +226,27 @@ proc synPacket*(seqNr: uint16, rcvConnectionId: uint16, bufferSize: uint32): Pac
|
|||
ackNr: 0'u16
|
||||
)
|
||||
|
||||
Packet(header: h, payload: @[])
|
||||
Packet(header: h, eack: none[SelectiveAckExtension](), payload: @[])
|
||||
|
||||
proc ackPacket*(
|
||||
seqNr: uint16,
|
||||
sndConnectionId: uint16,
|
||||
ackNr: uint16,
|
||||
bufferSize: uint32,
|
||||
timestampDiff: uint32,
|
||||
acksBitmask: Option[array[4, byte]] = none[array[4, byte]]()
|
||||
): Packet =
|
||||
|
||||
let (extensionByte, extensionData) =
|
||||
if acksBitmask.isSome():
|
||||
(1'u8, some(SelectiveAckExtension(acks: acksBitmask.unsafeGet())))
|
||||
else:
|
||||
(0'u8, none[SelectiveAckExtension]())
|
||||
|
||||
proc ackPacket*(seqNr: uint16, sndConnectionId: uint16, ackNr: uint16, bufferSize: uint32, timestampDiff: uint32): Packet =
|
||||
let h = PacketHeaderV1(
|
||||
pType: ST_STATE,
|
||||
version: protocolVersion,
|
||||
# TODO Handle selective acks
|
||||
extension: 0'u8,
|
||||
extension: extensionByte,
|
||||
connectionId: sndConnectionId,
|
||||
timestamp: getMonoTimestamp().timestamp,
|
||||
timestampDiff: timestampDiff,
|
||||
|
|
@ -190,7 +255,8 @@ proc ackPacket*(seqNr: uint16, sndConnectionId: uint16, ackNr: uint16, bufferSiz
|
|||
ackNr: ackNr
|
||||
)
|
||||
|
||||
Packet(header: h, payload: @[])
|
||||
|
||||
Packet(header: h, eack: extensionData, payload: @[])
|
||||
|
||||
proc dataPacket*(
|
||||
seqNr: uint16,
|
||||
|
|
@ -213,7 +279,7 @@ proc dataPacket*(
|
|||
ackNr: ackNr
|
||||
)
|
||||
|
||||
Packet(header: h, payload: payload)
|
||||
Packet(header: h, eack: none[SelectiveAckExtension](), payload: payload)
|
||||
|
||||
proc resetPacket*(seqNr: uint16, sndConnectionId: uint16, ackNr: uint16): Packet =
|
||||
let h = PacketHeaderV1(
|
||||
|
|
@ -231,7 +297,7 @@ proc resetPacket*(seqNr: uint16, sndConnectionId: uint16, ackNr: uint16): Packet
|
|||
ackNr: ackNr
|
||||
)
|
||||
|
||||
Packet(header: h, payload: @[])
|
||||
Packet(header: h, eack: none[SelectiveAckExtension](), payload: @[])
|
||||
|
||||
proc finPacket*(
|
||||
seqNr: uint16,
|
||||
|
|
@ -253,4 +319,4 @@ proc finPacket*(
|
|||
ackNr: ackNr
|
||||
)
|
||||
|
||||
Packet(header: h, payload: @[])
|
||||
Packet(header: h, eack: none[SelectiveAckExtension](), payload: @[])
|
||||
|
|
|
|||
|
|
@ -7,6 +7,7 @@
|
|||
{.used.}
|
||||
|
||||
import
|
||||
std/options,
|
||||
unittest2,
|
||||
../../eth/utp/packets,
|
||||
../../eth/keys
|
||||
|
|
@ -21,8 +22,109 @@ suite "Utp packets encoding/decoding":
|
|||
let decoded = decodePacket(encoded)
|
||||
|
||||
check:
|
||||
len(encoded) == 20
|
||||
decoded.isOk()
|
||||
synPacket == decoded.get()
|
||||
|
||||
let synPacketDec = decoded.get()
|
||||
|
||||
check:
|
||||
synPacketDec == synPacket
|
||||
|
||||
test "Encode/decode fin packet":
|
||||
let finPacket = finPacket(5, 10, 20, 30, 40)
|
||||
let encoded = encodePacket(finPacket)
|
||||
let decoded = decodePacket(encoded)
|
||||
|
||||
check:
|
||||
len(encoded) == 20
|
||||
decoded.isOk()
|
||||
|
||||
let finPacketDec = decoded.get()
|
||||
|
||||
check:
|
||||
finPacketDec == finPacket
|
||||
|
||||
test "Encode/decode reset packet":
|
||||
let resetPacket = resetPacket(5, 10, 20)
|
||||
let encoded = encodePacket(resetPacket)
|
||||
let decoded = decodePacket(encoded)
|
||||
|
||||
check:
|
||||
len(encoded) == 20
|
||||
decoded.isOk()
|
||||
|
||||
let resetPacketDec = decoded.get()
|
||||
|
||||
check:
|
||||
resetPacketDec == resetPacket
|
||||
|
||||
test "Encode/decode ack packet without extensions":
|
||||
let ackPacket = ackPacket(5, 10, 20, 30, 40)
|
||||
let encoded = encodePacket(ackPacket)
|
||||
let decoded = decodePacket(encoded)
|
||||
|
||||
check:
|
||||
len(encoded) == 20
|
||||
decoded.isOk()
|
||||
|
||||
let ackPacketDec = decoded.get()
|
||||
|
||||
check:
|
||||
ackPacketDec == ackPacket
|
||||
|
||||
test "Encode/decode ack packet with extensions":
|
||||
let bitMask: array[4, byte] = [1'u8, 2, 3, 4]
|
||||
let ackPacket = ackPacket(5, 10, 20, 30, 40, some(bitMask))
|
||||
let encoded = encodePacket(ackPacket)
|
||||
let decoded = decodePacket(encoded)
|
||||
|
||||
check:
|
||||
len(encoded) == 26
|
||||
decoded.isOk()
|
||||
|
||||
let ackPacketDec = decoded.get()
|
||||
|
||||
check:
|
||||
ackPacketDec == ackPacket
|
||||
ackPacketDec.eack.isSome()
|
||||
|
||||
test "Fail to decode packet with malformed extensions":
|
||||
let bitMask: array[4, byte] = [1'u8, 2, 3, 4]
|
||||
let ackPacket = ackPacket(5, 10, 20, 30, 40, some(bitMask))
|
||||
|
||||
var encoded1 = encodePacket(ackPacket)
|
||||
# change nextExtension to non zero
|
||||
encoded1[20] = 1
|
||||
let err1 = decodePacket(encoded1)
|
||||
check:
|
||||
err1.isErr()
|
||||
err1.error() == "Bad format of selective ack extension"
|
||||
|
||||
var encoded2 = encodePacket(ackPacket)
|
||||
# change len of extension to value different than 4
|
||||
encoded2[21] = 7
|
||||
let err2 = decodePacket(encoded2)
|
||||
check:
|
||||
err2.isErr()
|
||||
err2.error() == "Bad format of selective ack extension"
|
||||
|
||||
var encoded3 = encodePacket(ackPacket)
|
||||
# delete last byte, now packet is to short
|
||||
encoded3.del(encoded3.high)
|
||||
let err3 = decodePacket(encoded3)
|
||||
|
||||
check:
|
||||
err3.isErr()
|
||||
err3.error() == "Packet too short for selective ack extension"
|
||||
|
||||
|
||||
var encoded4 = encodePacket(ackPacket)
|
||||
# change change extension field to something other than 0 or 1
|
||||
encoded4[1] = 2
|
||||
let err4 = decodePacket(encoded4)
|
||||
check:
|
||||
err4.isErr()
|
||||
err4.error() == "Invalid extension type"
|
||||
|
||||
test "Decode state packet":
|
||||
# Packet obtained by interaction with c reference implementation
|
||||
|
|
|
|||
Loading…
Reference in New Issue