nim-eth-p2p/eth_p2p/discovery.nim

327 lines
13 KiB
Nim

#
# Ethereum P2P
# (c) Copyright 2018
# Status Research & Development GmbH
#
# Licensed under either of
# Apache License, version 2.0, (LICENSE-APACHEv2)
# MIT license (LICENSE-MIT)
#
import
times,
asyncdispatch2, eth_keys, stint, nimcrypto, rlp, chronicles,
kademlia, enode
export
Node
logScope:
topics = "discovery"
const
MAINNET_BOOTNODES* = [
"enode://a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@52.16.188.185:30303", # noqa: E501
"enode://aa36fdf33dd030378a0168efe6ed7d5cc587fafa3cdd375854fe735a2e11ea3650ba29644e2db48368c46e1f60e716300ba49396cd63778bf8a818c09bded46f@13.93.211.84:30303", # noqa: E501
"enode://78de8a0916848093c73790ead81d1928bec737d565119932b98c6b100d944b7a95e94f847f689fc723399d2e31129d182f7ef3863f2b4c820abbf3ab2722344d@191.235.84.50:30303", # noqa: E501
"enode://158f8aab45f6d19c6cbf4a089c2670541a8da11978a2f90dbf6a502a4a3bab80d288afdbeb7ec0ef6d92de563767f3b1ea9e8e334ca711e9f8e2df5a0385e8e6@13.75.154.138:30303", # noqa: E501
"enode://1118980bf48b0a3640bdba04e0fe78b1add18e1cd99bf22d53daac1fd9972ad650df52176e7c7d89d1114cfef2bc23a2959aa54998a46afcf7d91809f0855082@52.74.57.123:30303", # noqa: E501
]
ROPSTEN_BOOTNODES* = [
"enode://30b7ab30a01c124a6cceca36863ece12c4f5fa68e3ba9b0b51407ccc002eeed3b3102d20a88f1c1d3c3154e2449317b8ef95090e77b312d5cc39354f86d5d606@52.176.7.10:30303", # noqa: E501
"enode://865a63255b3bb68023b6bffd5095118fcc13e79dcf014fe4e47e065c350c7cc72af2e53eff895f11ba1bbb6a2b33271c1116ee870f266618eadfc2e78aa7349c@52.176.100.77:30303", # noqa: E501
"enode://6332792c4a00e3e4ee0926ed89e0d27ef985424d97b6a45bf0f23e51f0dcb5e66b875777506458aea7af6f9e4ffb69f43f3778ee73c81ed9d34c51c4b16b0b0f@52.232.243.152:30303", # noqa: E501
"enode://94c15d1b9e2fe7ce56e458b9a3b672ef11894ddedd0c6f247e0f1d3487f52b66208fb4aeb8179fce6e3a749ea93ed147c37976d67af557508d199d9594c35f09@192.81.208.223:30303", # noqa: E501
]
LOCAL_BOOTNODES = [
"enode://6456719e7267e061161c88720287a77b80718d2a3a4ff5daeba614d029dc77601b75e32190aed1c9b0b9ccb6fac3bcf000f48e54079fa79e339c25d8e9724226@127.0.0.1:30301"
]
# UDP packet constants.
MAC_SIZE = 256 div 8 # 32
SIG_SIZE = 520 div 8 # 65
HEAD_SIZE = MAC_SIZE + SIG_SIZE # 97
EXPIRATION = 60 # let messages expire after N secondes
PROTO_VERSION = 4
type
DiscoveryProtocol* = ref object
privKey: PrivateKey
address: Address
bootstrapNodes*: seq[Node]
thisNode*: Node
kademlia: KademliaProtocol[DiscoveryProtocol]
transp: DatagramTransport
CommandId = enum
cmdPing = 1
cmdPong = 2
cmdFindNode = 3
cmdNeighbours = 4
const MaxDgramSize = 1280
proc append*(w: var RlpWriter, a: IpAddress) =
case a.family
of IpAddressFamily.IPv6:
w.append(a.address_v6.toMemRange)
of IpAddressFamily.IPv4:
w.append(a.address_v4.toMemRange)
proc append(w: var RlpWriter, p: Port) {.inline.} = w.append(p.int)
proc append(w: var RlpWriter, pk: PublicKey) {.inline.} = w.append(pk.getRaw())
proc append(w: var RlpWriter, h: MDigest[256]) {.inline.} = w.append(h.data)
proc pack(cmdId: CommandId, payload: BytesRange, pk: PrivateKey): Bytes =
## Create and sign a UDP message to be sent to a remote node.
##
## See https://github.com/ethereum/devp2p/blob/master/rlpx.md#node-discovery for information on
## how UDP packets are structured.
# TODO: There is a lot of unneeded allocations here
let encodedData = @[cmdId.byte] & payload.toSeq()
let signature = @(pk.signMessage(encodedData).getRaw())
let msgHash = keccak256.digest(signature & encodedData)
result = @(msgHash.data) & signature & encodedData
proc validateMsgHash(msg: Bytes, msgHash: var MDigest[256]): bool =
msgHash.data[0 .. ^1] = msg.toOpenArray(0, msgHash.data.high)
result = msgHash == keccak256.digest(msg.toOpenArray(MAC_SIZE, msg.high))
proc recoverMsgPublicKey(msg: Bytes, pk: var PublicKey): bool =
recoverSignatureKey(msg.toOpenArray(MAC_SIZE, MAC_SIZE + 65),
keccak256.digest(msg.toOpenArray(HEAD_SIZE, msg.high)).data,
pk) == EthKeysStatus.Success
proc unpack(msg: Bytes): tuple[cmdId: CommandId, payload: Bytes] =
result = (cmdId: msg[HEAD_SIZE].CommandId, payload: msg[HEAD_SIZE + 1 .. ^1])
proc expiration(): uint32 =
result = uint32(epochTime() + EXPIRATION)
# Wire protocol
proc send(d: DiscoveryProtocol, n: Node, data: seq[byte]) =
let ta = initTAddress(n.node.address.ip, n.node.address.udpPort)
let f = d.transp.sendTo(ta, data)
f.callback = proc(data: pointer) {.gcsafe.} =
if f.failed:
debug "Discovery send failed", msg = f.readError.msg
proc sendPing*(d: DiscoveryProtocol, n: Node): seq[byte] =
let payload = rlp.encode((PROTO_VERSION, d.address, n.node.address,
expiration())).toRange
let msg = pack(cmdPing, payload, d.privKey)
result = msg[0 ..< MAC_SIZE]
trace ">>> ping ", n
d.send(n, msg)
proc sendPong*(d: DiscoveryProtocol, n: Node, token: MDigest[256]) =
let payload = rlp.encode((n.node.address, token, expiration())).toRange
let msg = pack(cmdPong, payload, d.privKey)
trace ">>> pong ", n
d.send(n, msg)
proc sendFindNode*(d: DiscoveryProtocol, n: Node, targetNodeId: NodeId) =
var data: array[64, byte]
data[32 .. ^1] = targetNodeId.toByteArrayBE()
let payload = rlp.encode((data, expiration())).toRange
let msg = pack(cmdFindNode, payload, d.privKey)
trace ">>> find_node to ", n#, ": ", msg.toHex()
d.send(n, msg)
proc sendNeighbours*(d: DiscoveryProtocol, node: Node, neighbours: seq[Node]) =
const MAX_NEIGHBOURS_PER_PACKET = 12 # TODO: Implement a smarter way to compute it
type Neighbour = tuple[ip: IpAddress, udpPort, tcpPort: Port, pk: PublicKey]
var nodes = newSeqOfCap[Neighbour](MAX_NEIGHBOURS_PER_PACKET)
shallow(nodes)
template flush() =
block:
let payload = rlp.encode((nodes, expiration())).toRange
let msg = pack(cmdNeighbours, payload, d.privkey)
trace "Neighbours to", node, nodes
d.send(node, msg)
nodes.setLen(0)
for i, n in neighbours:
nodes.add((n.node.address.ip, n.node.address.udpPort,
n.node.address.tcpPort, n.node.pubkey))
if nodes.len == MAX_NEIGHBOURS_PER_PACKET:
flush()
if nodes.len != 0: flush()
proc newDiscoveryProtocol*(privKey: PrivateKey, address: Address,
bootstrapNodes: openarray[ENode]
): DiscoveryProtocol =
result.new()
result.privKey = privKey
result.address = address
result.bootstrapNodes = newSeqOfCap[Node](bootstrapNodes.len)
for n in bootstrapNodes: result.bootstrapNodes.add(newNode(n))
result.thisNode = newNode(privKey.getPublicKey(), address)
result.kademlia = newKademliaProtocol(result.thisNode, result)
proc recvPing(d: DiscoveryProtocol, node: Node,
msgHash: MDigest[256]) {.inline.} =
d.kademlia.recvPing(node, msgHash)
proc recvPong(d: DiscoveryProtocol, node: Node, payload: Bytes) {.inline.} =
let rlp = rlpFromBytes(payload.toRange)
let tok = rlp.listElem(1).toBytes().toSeq()
d.kademlia.recvPong(node, tok)
proc recvNeighbours(d: DiscoveryProtocol, node: Node,
payload: Bytes) {.inline.} =
let rlp = rlpFromBytes(payload.toRange)
let neighboursList = rlp.listElem(0)
let sz = neighboursList.listLen()
var neighbours = newSeqOfCap[Node](16)
for i in 0 ..< sz:
let n = neighboursList.listElem(i)
let ipBlob = n.listElem(0).toBytes
var ip: IpAddress
case ipBlob.len
of 4:
ip = IpAddress(family: IpAddressFamily.IPv4)
copyMem(addr ip.address_v4[0], baseAddr ipBlob, 4)
of 16:
ip = IpAddress(family: IpAddressFamily.IPv6)
copyMem(addr ip.address_v6[0], baseAddr ipBlob, 16)
else:
error "Wrong ip address length!"
continue
let udpPort = n.listElem(1).toInt(uint16).Port
let tcpPort = n.listElem(2).toInt(uint16).Port
var pk: PublicKey
if recoverPublicKey(n.listElem(3).toBytes.toOpenArray(), pk) != EthKeysStatus.Success:
warn "Could not parse public key"
continue
neighbours.add(newNode(pk, Address(ip: ip, udpPort: udpPort, tcpPort: tcpPort)))
d.kademlia.recvNeighbours(node, neighbours)
proc recvFindNode(d: DiscoveryProtocol, node: Node, payload: Bytes) {.inline.} =
let rlp = rlpFromBytes(payload.toRange)
trace "<<< find_node from ", node
let rng = rlp.listElem(0).toBytes
let nodeId = readUIntBE[256](rng[32 .. ^1].toOpenArray())
d.kademlia.recvFindNode(node, nodeId)
proc expirationValid(rlpEncodedPayload: seq[byte]): bool {.inline.} =
let rlp = rlpFromBytes(rlpEncodedPayload.toRange)
let expiration = rlp.listElem(rlp.listLen - 1).toInt(uint32)
result = epochTime() <= expiration.float
proc receive(d: DiscoveryProtocol, a: Address, msg: Bytes) =
var msgHash: MDigest[256]
if validateMsgHash(msg, msgHash):
var remotePubkey: PublicKey
if recoverMsgPublicKey(msg, remotePubkey):
let (cmdId, payload) = unpack(msg)
# echo "received cmd: ", cmdId, ", from: ", a
# echo "pubkey: ", remotePubkey.raw_key.toHex()
if expirationValid(payload):
let node = newNode(remotePubkey, a)
case cmdId
of cmdPing:
d.recvPing(node, msgHash)
of cmdPong:
d.recvPong(node, payload)
of cmdNeighbours:
d.recvNeighbours(node, payload)
of cmdFindNode:
d.recvFindNode(node, payload)
else:
trace "Received msg already expired", cmdId, a
else:
error "Wrong public key from ", a
else:
error "Wrong msg mac from ", a
proc processClient(transp: DatagramTransport,
raddr: TransportAddress): Future[void] {.async, gcsafe.} =
var proto = getUserData[DiscoveryProtocol](transp)
var buf: seq[byte]
try:
# TODO: Maybe here better to use `peekMessage()` to avoid allocation,
# but `Bytes` object is just a simple seq[byte], and `ByteRange` object
# do not support custom length.
var buf = transp.getMessage()
let a = Address(ip: raddr.address, udpPort: raddr.port, tcpPort: raddr.port)
proto.receive(a, buf)
except:
debug "Receive failed", err = getCurrentExceptionMsg()
proc open*(d: DiscoveryProtocol) =
let ta = initTAddress(d.address.ip, d.address.udpPort)
d.transp = newDatagramTransport(processClient, udata = d, local = ta)
proc lookupRandom*(d: DiscoveryProtocol): Future[seq[Node]] {.inline.} =
d.kademlia.lookupRandom()
proc run(d: DiscoveryProtocol) {.async.} =
while true:
discard await d.lookupRandom()
await sleepAsync(3000)
trace "Discovered nodes", nodes = d.kademlia.nodesDiscovered
proc bootstrap*(d: DiscoveryProtocol) {.async.} =
await d.kademlia.bootstrap(d.bootstrapNodes)
discard d.run()
proc resolve*(d: DiscoveryProtocol, n: NodeId): Future[Node] =
d.kademlia.resolve(n)
proc randomNodes*(d: DiscoveryProtocol, count: int): seq[Node] {.inline.} =
d.kademlia.randomNodes(count)
when isMainModule:
import logging, byteutils
addHandler(newConsoleLogger())
block:
let m = hexToSeqByte"79664bff52ee17327b4a2d8f97d8fb32c9244d719e5038eb4f6b64da19ca6d271d659c3ad9ad7861a928ca85f8d8debfbe6b7ade26ad778f2ae2ba712567fcbd55bc09eb3e74a893d6b180370b266f6aaf3fe58a0ad95f7435bf3ddf1db940d20102f2cb842edbd4d182944382765da0ab56fb9e64a85a597e6bb27c656b4f1afb7e06b0fd4e41ccde6dba69a3c4a150845aaa4de2"
var msgHash: MDigest[256]
doAssert(validateMsgHash(m, msgHash))
var remotePubkey: PublicKey
doAssert(recoverMsgPublicKey(m, remotePubkey))
let (cmdId, payload) = unpack(m)
assert(payload == hexToSeqByte"f2cb842edbd4d182944382765da0ab56fb9e64a85a597e6bb27c656b4f1afb7e06b0fd4e41ccde6dba69a3c4a150845aaa4de2")
assert(cmdId == cmdPong)
assert(remotePubkey == initPublicKey("78de8a0916848093c73790ead81d1928bec737d565119932b98c6b100d944b7a95e94f847f689fc723399d2e31129d182f7ef3863f2b4c820abbf3ab2722344d"))
let privKey = initPrivateKey("a2b50376a79b1a8c8a3296485572bdfbf54708bb46d3c25d73d2723aaaf6a617")
# echo privKey
# block:
# var b = @[1.byte, 2, 3]
# let m = pack(cmdPing, b.initBytesRange, privKey)
# let (remotePubkey, cmdId, payload) = unpack(m)
# assert(remotePubkey.raw_key.toHex == privKey.public_key.raw_key.toHex)
var bootnodes = newSeq[ENode]()
for item in LOCAL_BOOTNODES:
bootnodes.add(initENode(item))
let listenPort = Port(30310)
var address = Address(udpPort: listenPort, tcpPort: listenPort)
address.ip.family = IpAddressFamily.IPv4
let discovery = newDiscoveryProtocol(privkey, address, bootnodes)
echo discovery.thisNode.node.pubkey
echo "this_node.id: ", discovery.thisNode.id.toHex()
discovery.open()
proc test() {.async.} =
await discovery.bootstrap()
waitFor test()