nim-libp2p-experimental/libp2p/protocols/ping.nim

105 lines
2.6 KiB
Nim

# Nim-LibP2P
# Copyright (c) 2023 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.
## `Ping <https://docs.libp2p.io/concepts/protocols/#ping>`_ protocol implementation
when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import chronos, chronicles
import bearssl/rand
import ../protobuf/minprotobuf,
../peerinfo,
../stream/connection,
../peerid,
../crypto/crypto,
../multiaddress,
../protocols/protocol,
../utility,
../errors
export chronicles, rand, connection
logScope:
topics = "libp2p ping"
const
PingCodec* = "/ipfs/ping/1.0.0"
PingSize = 32
type
PingError* = object of LPError
WrongPingAckError* = object of PingError
PingHandler* {.public.} = proc (
peer: PeerId):
Future[void]
{.gcsafe, raises: [Defect].}
Ping* = ref object of LPProtocol
pingHandler*: PingHandler
rng: ref HmacDrbgContext
proc new*(T: typedesc[Ping], handler: PingHandler = nil, rng: ref HmacDrbgContext = newRng()): T {.public.} =
let ping = Ping(pinghandler: handler, rng: rng)
ping.init()
ping
method init*(p: Ping) =
proc handle(conn: Connection, proto: string) {.async, gcsafe, closure.} =
try:
trace "handling ping", conn
var buf: array[PingSize, byte]
await conn.readExactly(addr buf[0], PingSize)
trace "echoing ping", conn
await conn.write(@buf)
if not isNil(p.pingHandler):
await p.pingHandler(conn.peerId)
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "exception in ping handler", exc = exc.msg, conn
p.handler = handle
p.codec = PingCodec
proc ping*(
p: Ping,
conn: Connection,
): Future[Duration] {.async, gcsafe, public.} =
## Sends ping to `conn`, returns the delay
trace "initiating ping", conn
var
randomBuf: array[PingSize, byte]
resultBuf: array[PingSize, byte]
hmacDrbgGenerate(p.rng[], randomBuf)
let startTime = Moment.now()
trace "sending ping", conn
await conn.write(@randomBuf)
await conn.readExactly(addr resultBuf[0], PingSize)
let responseDur = Moment.now() - startTime
trace "got ping response", conn, responseDur
for i in 0..<randomBuf.len:
if randomBuf[i] != resultBuf[i]:
raise newException(WrongPingAckError, "Incorrect ping data from peer!")
trace "valid ping response", conn
return responseDur