mirror of https://github.com/status-im/nim-eth.git
121 lines
3.6 KiB
Nim
121 lines
3.6 KiB
Nim
# nim-eth - Node Discovery Protocol v5
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# Copyright (c) 2020-2022 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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#
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## Discovery v5 Protocol Messages RLP Encoding
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{.push raises: [Defect].}
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import
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std/net,
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stew/[arrayops, results],
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../../rlp,
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"."/[messages, enr]
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from stew/objects import checkedEnumAssign
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export messages, rlp, results
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func read*(rlp: var Rlp, T: type RequestId): T
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{.raises: [ValueError, RlpError, Defect].} =
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mixin read
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var reqId: RequestId
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reqId.id = rlp.toBytes()
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if reqId.id.len > 8:
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raise newException(ValueError, "RequestId is > 8 bytes")
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rlp.skipElem()
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reqId
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func append*(writer: var RlpWriter, value: RequestId) =
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writer.append(value.id)
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func read*(rlp: var Rlp, T: type IpAddress): T
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{.raises: [RlpError, Defect].} =
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let ipBytes = rlp.toBytes()
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rlp.skipElem()
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if ipBytes.len == 4:
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var ip: array[4, byte]
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discard copyFrom(ip, ipBytes)
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IpAddress(family: IPv4, address_v4: ip)
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elif ipBytes.len == 16:
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var ip: array[16, byte]
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discard copyFrom(ip, ipBytes)
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IpAddress(family: IPv6, address_v6: ip)
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else:
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raise newException(RlpTypeMismatch,
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"Amount of bytes for IP address is different from 4 or 16")
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func append*(writer: var RlpWriter, ip: IpAddress) =
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case ip.family:
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of IpAddressFamily.IPv4:
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writer.append(ip.address_v4)
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of IpAddressFamily.IPv6:
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writer.append(ip.address_v6)
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func numFields(T: typedesc): int =
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for k, v in fieldPairs(default(T)): inc result
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func encodeMessage*[T: SomeMessage](p: T, reqId: RequestId): seq[byte] =
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## Encodes a message with provided `reqId`.
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var bytes = newSeqOfCap[byte](64)
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bytes.add(messageKind(T).ord)
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const sz = numFields(T)
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var writer = initRlpList(sz + 1)
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writer.append(reqId)
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for k, v in fieldPairs(p):
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writer.append(v)
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bytes.add(writer.finish())
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bytes
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func decodeMessage*(body: openArray[byte]): Result[Message, cstring] =
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## Decodes to the specific `Message` type.
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if body.len < 1:
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return err("No message data")
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var kind: MessageKind
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if not checkedEnumAssign(kind, body[0]):
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return err("Invalid message type")
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var message = Message(kind: kind)
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var rlp = rlpFromBytes(body.toOpenArray(1, body.high))
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if rlp.enterList:
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try:
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message.reqId = rlp.read(RequestId)
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except RlpError, ValueError:
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return err("Invalid request-id")
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func decode[T](rlp: var Rlp, v: var T)
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{.nimcall, raises:[RlpError, ValueError, Defect].} =
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for k, v in v.fieldPairs:
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v = rlp.read(typeof(v))
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try:
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case kind
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of unused: return err("Invalid message type")
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of ping: rlp.decode(message.ping)
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of pong: rlp.decode(message.pong)
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of findNode: rlp.decode(message.findNode)
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of nodes: rlp.decode(message.nodes)
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of talkReq: rlp.decode(message.talkReq)
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of talkResp: rlp.decode(message.talkResp)
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of regTopic, ticket, regConfirmation, topicQuery:
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# We just pass the empty type of this message without attempting to
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# decode, so that the protocol knows what was received.
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# But we ignore the message as per specification as "the content and
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# semantics of this message are not final".
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discard
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except RlpError, ValueError:
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return err("Invalid message encoding")
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ok(message)
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else:
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err("Invalid message encoding: no rlp list")
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