mirror of https://github.com/waku-org/nwaku.git
129 lines
3.8 KiB
Nim
129 lines
3.8 KiB
Nim
{.push raises: [].}
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## A set of utilities to integrate EIP-1459 DNS-based discovery
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## for Waku v2 nodes.
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##
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## EIP-1459 is defined in https://eips.ethereum.org/EIPS/eip-1459
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import
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std/[options, net],
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chronicles,
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chronos,
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metrics,
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eth/keys,
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eth/p2p/discoveryv5/enr,
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libp2p/crypto/crypto,
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libp2p/crypto/secp,
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libp2p/multiaddress,
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libp2p/peerid,
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dnsdisc/client
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import libp2p/nameresolving/dnsresolver
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import ../waku_core
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export client
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declarePublicGauge waku_dnsdisc_discovered, "number of nodes discovered"
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declarePublicGauge waku_dnsdisc_errors, "number of waku dnsdisc errors", ["type"]
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logScope:
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topics = "waku dnsdisc"
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type WakuDnsDiscovery* = object
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client*: Client
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resolver*: Resolver
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#####################
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# DNS Discovery API #
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#####################
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proc emptyResolver*(domain: string): Future[string] {.async, gcsafe.} =
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debug "Empty resolver called", domain = domain
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return ""
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proc findPeers*(wdd: var WakuDnsDiscovery): Result[seq[RemotePeerInfo], cstring] =
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## Find peers to connect to using DNS based discovery
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info "Finding peers using Waku DNS discovery"
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# Synchronise client tree using configured resolver
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var tree: Tree
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try:
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tree = wdd.client.getTree(wdd.resolver)
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# @TODO: this is currently a blocking operation to not violate memory safety
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except Exception:
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error "Failed to synchronise client tree"
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waku_dnsdisc_errors.inc(labelValues = ["tree_sync_failure"])
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return err("Node discovery failed")
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let discoveredEnr = wdd.client.getNodeRecords()
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if discoveredEnr.len > 0:
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info "Successfully discovered ENR", count = discoveredEnr.len
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else:
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trace "No ENR retrieved from client tree"
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var discoveredNodes: seq[RemotePeerInfo]
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for enr in discoveredEnr:
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# Convert discovered ENR to RemotePeerInfo and add to discovered nodes
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let res = enr.toRemotePeerInfo()
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if res.isOk():
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discoveredNodes.add(res.get())
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else:
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error "Failed to convert ENR to peer info", enr = $enr, err = res.error()
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waku_dnsdisc_errors.inc(labelValues = ["peer_info_failure"])
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if discoveredNodes.len > 0:
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info "Successfully discovered nodes", count = discoveredNodes.len
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waku_dnsdisc_discovered.inc(discoveredNodes.len.int64)
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return ok(discoveredNodes)
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proc init*(
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T: type WakuDnsDiscovery, locationUrl: string, resolver: Resolver
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): Result[T, cstring] =
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## Initialise Waku peer discovery via DNS
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debug "init WakuDnsDiscovery", locationUrl = locationUrl
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let
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client = ?Client.init(locationUrl)
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wakuDnsDisc = WakuDnsDiscovery(client: client, resolver: resolver)
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debug "init success"
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return ok(wakuDnsDisc)
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proc retrieveDynamicBootstrapNodes*(
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dnsDiscovery: bool, dnsDiscoveryUrl: string, dnsDiscoveryNameServers: seq[IpAddress]
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): Result[seq[RemotePeerInfo], string] =
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## Retrieve dynamic bootstrap nodes (DNS discovery)
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if dnsDiscovery and dnsDiscoveryUrl != "":
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# DNS discovery
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debug "Discovering nodes using Waku DNS discovery", url = dnsDiscoveryUrl
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var nameServers: seq[TransportAddress]
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for ip in dnsDiscoveryNameServers:
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nameServers.add(initTAddress(ip, Port(53))) # Assume all servers use port 53
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let dnsResolver = DnsResolver.new(nameServers)
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proc resolver(domain: string): Future[string] {.async, gcsafe.} =
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trace "resolving", domain = domain
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let resolved = await dnsResolver.resolveTxt(domain)
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return resolved[0] # Use only first answer
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var wakuDnsDiscovery = WakuDnsDiscovery.init(dnsDiscoveryUrl, resolver)
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if wakuDnsDiscovery.isOk():
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return wakuDnsDiscovery.get().findPeers().mapErr(
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proc(e: cstring): string =
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$e
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)
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else:
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warn "Failed to init Waku DNS discovery"
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debug "No method for retrieving dynamic bootstrap nodes specified."
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ok(newSeq[RemotePeerInfo]()) # Return an empty seq by default
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