90 lines
2.4 KiB
Nim
90 lines
2.4 KiB
Nim
## Nim-LibP2P
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## Copyright (c) 2019 Status Research & Development GmbH
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## Licensed under either of
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## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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import chronos
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import nimcrypto/utils, chronicles, stew/byteutils
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import ../../stream/connection,
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../../utility,
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../../varint,
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../../vbuffer
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logScope:
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topics = "libp2p mplexcoder"
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type
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MessageType* {.pure.} = enum
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New,
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MsgIn,
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MsgOut,
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CloseIn,
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CloseOut,
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ResetIn,
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ResetOut
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Msg* = tuple
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id: uint64
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msgType: MessageType
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data: seq[byte]
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InvalidMplexMsgType = object of CatchableError
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# https://github.com/libp2p/specs/tree/master/mplex#writing-to-a-stream
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const MaxMsgSize* = 1 shl 20 # 1mb
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proc newInvalidMplexMsgType*(): ref InvalidMplexMsgType =
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newException(InvalidMplexMsgType, "invalid message type")
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proc readMsg*(conn: Connection): Future[Msg] {.async, gcsafe.} =
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let header = await conn.readVarint()
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trace "read header varint", varint = header, conn
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let data = await conn.readLp(MaxMsgSize)
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trace "read data", dataLen = data.len, data = shortLog(data), conn
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let msgType = header and 0x7
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if msgType.int > ord(MessageType.ResetOut):
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raise newInvalidMplexMsgType()
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return (header shr 3, MessageType(msgType), data)
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proc writeMsg*(conn: Connection,
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id: uint64,
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msgType: MessageType,
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data: seq[byte] = @[]): Future[void] =
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var
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left = data.len
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offset = 0
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buf = initVBuffer()
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# Split message into length-prefixed chunks
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while left > 0 or data.len == 0:
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let
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chunkSize = if left > MaxMsgSize: MaxMsgSize - 64 else: left
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buf.writePBVarint(id shl 3 or ord(msgType).uint64)
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buf.writeSeq(data.toOpenArray(offset, offset + chunkSize - 1))
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left = left - chunkSize
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offset = offset + chunkSize
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if data.len == 0:
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break
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trace "writing mplex message",
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conn, id, msgType, data = data.len, encoded = buf.buffer.len
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# Write all chunks in a single write to avoid async races where a close
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# message gets written before some of the chunks
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conn.write(buf.buffer)
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proc writeMsg*(conn: Connection,
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id: uint64,
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msgType: MessageType,
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data: string): Future[void] =
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conn.writeMsg(id, msgType, data.toBytes())
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