nwaku/waku/waku_enr/multiaddr.nim

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when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import
std/[options, sequtils],
stew/[endians2, results],
stew/shims/net,
eth/keys,
libp2p/[multiaddress, multicodec],
libp2p/crypto/crypto
import
../common/enr
const
MultiaddrEnrField* = "multiaddrs"
func encodeMultiaddrs*(multiaddrs: seq[MultiAddress]): seq[byte] =
var buffer = newSeq[byte]()
for multiaddr in multiaddrs:
let
raw = multiaddr.data.buffer # binary encoded multiaddr
size = raw.len.uint16.toBytes(Endianness.bigEndian) # size as Big Endian unsigned 16-bit integer
buffer.add(concat(@size, raw))
buffer
func readBytes(rawBytes: seq[byte], numBytes: int, pos: var int = 0): Result[seq[byte], cstring] =
## Attempts to read `numBytes` from a sequence, from
## position `pos`. Returns the requested slice or
## an error if `rawBytes` boundary is exceeded.
##
## If successful, `pos` is advanced by `numBytes`
if rawBytes[pos..^1].len() < numBytes:
return err("insufficient bytes")
let slicedSeq = rawBytes[pos..<pos+numBytes]
pos += numBytes
return ok(slicedSeq)
func decodeMultiaddrs(buffer: seq[byte]): EnrResult[seq[MultiAddress]] =
## Parses a `multiaddrs` ENR field according to
## https://rfc.vac.dev/spec/31/
var multiaddrs: seq[MultiAddress]
var pos = 0
while pos < buffer.len():
let addrLenRaw = ? readBytes(buffer, 2, pos)
let addrLen = uint16.fromBytesBE(addrLenRaw)
if addrLen == 0:
# Ensure pos always advances and we don't get stuck in infinite loop
return err("malformed multiaddr field: invalid length")
let addrRaw = ? readBytes(buffer, addrLen.int, pos)
let address = MultiAddress.init(addrRaw).get()
multiaddrs.add(address)
return ok(multiaddrs)
# ENR builder extension
func stripPeerId(multiaddr: MultiAddress): MultiAddress =
if not multiaddr.contains(multiCodec("p2p")).get():
return multiaddr
var cleanAddr = MultiAddress.init()
for item in multiaddr.items:
if item.value.protoName().get() != "p2p":
# Add all parts except p2p peerId
discard cleanAddr.append(item.value)
return cleanAddr
func withMultiaddrs*(builder: var EnrBuilder, multiaddrs: seq[MultiAddress]) =
let multiaddrs = multiaddrs.map(stripPeerId)
let value = encodeMultiaddrs(multiaddrs)
builder.addFieldPair(MultiaddrEnrField, value)
func withMultiaddrs*(builder: var EnrBuilder, multiaddrs: varargs[MultiAddress]) =
withMultiaddrs(builder, @multiaddrs)
# ENR record accessors (e.g., Record, TypedRecord, etc.)
func multiaddrs*(record: TypedRecord): Option[seq[MultiAddress]] =
let field = record.tryGet(MultiaddrEnrField, seq[byte])
if field.isNone():
return none(seq[MultiAddress])
let decodeRes = decodeMultiaddrs(field.get())
if decodeRes.isErr():
return none(seq[MultiAddress])
some(decodeRes.value)