92 lines
2.9 KiB
Nim
92 lines
2.9 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
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import types,
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../../connection,
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../../utility,
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../../varint,
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../../vbuffer,
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../../stream/lpstream
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logScope:
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topic = "MplexCoder"
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type
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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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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
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let data = await conn.readLp(MaxMsgSize)
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trace "read data", dataLen = data.len, data = shortLog(data)
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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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result = (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] = @[]) {.async, gcsafe.} =
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trace "sending data over mplex", id,
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msgType,
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data = data.len
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try:
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var
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left = data.len
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offset = 0
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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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chunk = if chunkSize > 0 : data[offset..(offset + chunkSize - 1)] else: data
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## write lenght prefixed
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var buf = initVBuffer()
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buf.writePBVarint(id shl 3 or ord(msgType).uint64)
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buf.writePBVarint(chunkSize.uint64) # size should be always sent
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buf.finish()
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left = left - chunkSize
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offset = offset + chunkSize
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await conn.write(buf.buffer & chunk)
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if data.len == 0:
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return
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except LPStreamEOFError:
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trace "Ignoring EOF while writing"
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except CancelledError as exc:
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raise exc
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except CatchableError as exc:
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# TODO these exceptions are ignored since it's likely that if writes are
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# are failing, the underlying connection is already closed - this needs
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# more cleanup though
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debug "Could not write to connection", error = exc.name
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trace "Could not write to connection - verbose", msg = exc.msg
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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) {.async, gcsafe.} =
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# TODO: changing this to
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#`await conn.writeMsg(id, msgType, cast[seq[byte]](data))`
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# causes all sorts of race conditions and hangs.
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# DON'T DO IT!
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result = conn.writeMsg(id, msgType, cast[seq[byte]](data))
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