nim-codex-dht/eth/p2p/providers.nim
2022-02-23 22:12:32 +01:00

127 lines
4.1 KiB
Nim

# Copyright (c) 2020-2022 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
chronos,
chronicles,
std/tables,
stew/byteutils, # toBytes
discoveryv5/[protocol, node],
libp2p/routing_record,
libp2p/protobuf/minprotobuf
type
ProvidersProtocol* = ref object
providers: Table[NodeId, seq[PeerRecord]]
discovery*: protocol.Protocol
AddProviderMessage* = object
cId: NodeId
prov: PeerRecord
GetProvidersMessage* = object
cId: NodeId
ProvidersMessage* = object
total*: uint32
enrs*: seq[PeerRecord]
func getField*(pb: ProtoBuffer, field: int,
nid: var NodeId): ProtoResult[bool] {.inline.} =
## Read ``NodeId`` from ProtoBuf's message and validate it
var buffer: seq[byte]
let res = ? pb.getField(field, buffer)
if not(res):
ok(false)
else:
nid = readUintBE[256](buffer)
ok(true)
func write*(pb: var ProtoBuffer, field: int, nid: NodeId) =
## Write NodeId value ``nodeid`` to object ``pb`` using ProtoBuf's encoding.
write(pb, field, nid.toBytesBE())
func getField*(pb: ProtoBuffer, field: int,
pr: var PeerRecord): ProtoResult[bool] {.inline.} =
## Read ``NodeId`` from ProtoBuf's message and validate it
var buffer: seq[byte]
let res = ? pb.getField(field, buffer)
if not(res):
ok(false)
else:
let res2 = PeerRecord.decode(buffer)
if res2.isOk():
pr = res2.get()
ok(true)
else:
err(ProtoError.IncorrectBlob)
func write*(pb: var ProtoBuffer, field: int, pr: PeerRecord) =
## Write PeerRecord value ``pr`` to object ``pb`` using ProtoBuf's encoding.
write(pb, field, pr.encode())
proc decode*(
T: typedesc[AddProviderMessage],
buffer: openArray[byte]): Result[AddProviderMessage, ProtoError] =
let pb = initProtoBuffer(buffer)
var msg = AddProviderMessage()
? pb.getRequiredField(1, msg.cId)
? pb.getRequiredField(2, msg.prov)
ok(msg)
proc encode*(msg: AddProviderMessage): seq[byte] =
var pb = initProtoBuffer()
pb.write(1, msg.cId)
pb.write(2, msg.prov)
pb.finish()
pb.buffer
proc addProviderLocal(p: ProvidersProtocol, cId: NodeId, prov: PeerRecord) =
trace "adding provider to local db", n=p.discovery.localNode, cId, prov
p.providers.mgetOrPut(cId, @[]).add(prov)
proc recvAddProvider(p: ProvidersProtocol, nodeId: NodeId, payload: openArray[byte])
{.raises: [Defect].} =
#TODO: add checks, add signed version
let msg = AddProviderMessage.decode(payload).get()
trace "<<< add_provider ", src = nodeId, dst = p.discovery.localNode.id, cid = msg.cId, prov=msg.prov
p.addProviderLocal(msg.cId, msg.prov)
#TODO: check that CID is reasonably close to our NodeID
const
protoIdAddProvider = "AP".toBytes()
proc registerAddProvider(p: ProvidersProtocol) =
proc handler(protocol: TalkProtocol, request: seq[byte], fromId: NodeId, fromUdpAddress: Address): seq[byte]
{.gcsafe, raises: [Defect].} =
recvAddProvider(p, fromId, request)
@[] # talk requires a response
let protocol = TalkProtocol(protocolHandler: handler)
discard p.discovery.registerTalkProtocol(protoIdAddProvider, protocol) #TODO: handle error
proc sendAddProvider*(p: ProvidersProtocol, dst: Node, cId: NodeId, pr: PeerRecord) =
#type NodeDesc = tuple[ip: IpAddress, udpPort, tcpPort: Port, pk: PublicKey]
let msg = AddProviderMessage(cId: cId, prov: pr)
discard p.discovery.talkReq(dst, protoIdAddProvider, msg.encode())
proc addProvider*(p: ProvidersProtocol, cId: NodeId, pr: PeerRecord): Future[seq[Node]] {.async.} =
result = await p.discovery.lookup(cId)
trace "lookup returned:", result
# TODO: lookup is sepcified as not returning local, even if that is the closest. Is this OK?
if result.len == 0:
result.add(p.discovery.localNode)
for n in result:
if n != p.discovery.localNode:
p.sendAddProvider(n, cId, pr)
else:
p.addProviderLocal(cId, pr)