Integrate DNS resolution (#709)

* Update submodule

* Add DNS Client library

* Fork and update dnsclient submodule

* Integrate DNS resolution

.gitmodules

@@ -135,3 +135,8 @@
 	url = https://github.com/status-im/nim-dnsdisc.git
 	ignore = untracked
 	branch = main
+[submodule "vendor/dnsclient.nim"]
+	path = vendor/dnsclient.nim
+	url = https://github.com/jm-clius/dnsclient.nim.git
+	ignore = untracked
+	branch = master

examples/v2/chat2.nim

@@ -19,8 +19,10 @@ import libp2p/[switch,                   # manage transports, a single entry poi
                protobuf/minprotobuf,     # message serialisation/deserialisation from and to protobufs
                protocols/protocol,       # define the protocol base type
                protocols/secure/secio,   # define the protocol of secure input / output, allows encrypted communication that uses public keys to validate signed messages instead of a certificate authority like in TLS
+               nameresolving/dnsresolver,# define DNS resolution
                muxers/muxer]             # define an interface for stream multiplexing, allowing peers to offer many protocols over a single connection
 import   ../../waku/v2/node/[wakunode2, waku_payload],
+         ../../waku/v2/node/./dnsdisc/waku_dnsdisc,
          ../../waku/v2/utils/peers,
          ../../waku/common/utils/nat,
          ./config_chat2
@@ -344,6 +346,30 @@ proc processInput(rfd: AsyncFD, rng: ref BrHmacDrbgContext) {.async.} =
 
   if conf.staticnodes.len > 0:
     await connectToNodes(chat, conf.staticnodes)
+  elif conf.dnsDiscovery and conf.dnsDiscoveryUrl != "":
+      # Discover nodes via DNS
+      debug "Discovering nodes using Waku DNS discovery", url=conf.dnsDiscoveryUrl
+
+      var nameServers: seq[TransportAddress]
+      for ip in conf.dnsDiscoveryNameServers:
+        nameServers.add(initTAddress(ip, Port(53))) # Assume all servers use port 53
+
+      let dnsResolver = DnsResolver.new(nameServers)
+
+      proc resolver(domain: string): Future[string] {.async, gcsafe.} =
+        trace "resolving", domain=domain
+        let resolved = await dnsResolver.resolveTxt(domain)
+        return resolved[0] # Use only first answer
+      
+      var wakuDnsDiscovery = WakuDnsDiscovery.init(conf.dnsDiscoveryUrl,
+                                                   resolver)
+      if wakuDnsDiscovery.isOk:
+        let discoveredPeers = wakuDnsDiscovery.get().findPeers()
+        if discoveredPeers.isOk:
+          info "Connecting to discovered peers"
+          waitFor chat.node.connectToNodes(discoveredPeers.get())
+      else:
+        warn "Failed to init Waku DNS discovery"
   elif conf.fleet != Fleet.none:
     # Connect to at least one random fleet node
     echo "No static peers configured. Choosing one at random from " & $conf.fleet & " fleet..."

examples/v2/config_chat2.nim

@@ -186,6 +186,23 @@ type
       defaultValue: false
       name: "metrics-logging" }: bool
     
+    ## DNS discovery config
+    
+    dnsDiscovery* {.
+      desc: "Enable discovering nodes via DNS"
+      defaultValue: false
+      name: "dns-discovery" }: bool
+    
+    dnsDiscoveryUrl* {.
+      desc: "URL for DNS node list in format 'enrtree://<key>@<fqdn>'",
+      defaultValue: ""
+      name: "dns-discovery-url" }: string
+    
+    dnsDiscoveryNameServers* {.
+      desc: "DNS name server IPs to query. Argument may be repeated."
+      defaultValue: @[ValidIpAddress.init("1.1.1.1"), ValidIpAddress.init("1.0.0.1")]
+      name: "dns-discovery-name-server" }: seq[ValidIpAddress]
+
     ## Chat2 configuration
     
     fleet* {.

vendor/dnsclient.nim

@@ -0,0 +1 @@
+Subproject commit c3ddd26a2eece2a7bb558cb67d2f92846f9b8402

vendor/nim-libp2p

@@ -1 +1 @@
-Subproject commit c1b2d45d1b562df1af29012e58f33ff8bff597ac
+Subproject commit f274bfe19db5a39ffbca177b52db7e8a7eb44537

waku/v2/node/config.nim

@@ -193,6 +193,11 @@ type
       defaultValue: ""
       name: "dns-discovery-url" }: string
     
+    dnsDiscoveryNameServers* {.
+      desc: "DNS name server IPs to query. Argument may be repeated."
+      defaultValue: @[ValidIpAddress.init("1.1.1.1"), ValidIpAddress.init("1.0.0.1")]
+      name: "dns-discovery-name-server" }: seq[ValidIpAddress]
+
 # NOTE: Keys are different in nim-libp2p
 proc parseCmdArg*(T: type crypto.PrivateKey, p: TaintedString): T =
   try:

waku/v2/node/wakunode2.nim

@@ -9,6 +9,7 @@ import
   libp2p/crypto/crypto,
   libp2p/protocols/ping,
   libp2p/protocols/pubsub/gossipsub,
+  libp2p/nameresolving/dnsresolver,
   libp2p/builders,
   ../protocol/[waku_relay, waku_message],
   ../protocol/waku_store/waku_store,
@@ -850,11 +851,21 @@ when isMainModule:
     
     # Connect to discovered nodes
     if conf.dnsDiscovery and conf.dnsDiscoveryUrl != "":
-      # @ TODO: this is merely POC integration with an empty resolver
-      debug "Waku DNS Discovery enabled. Using empty resolver."
+      debug "Discovering nodes using Waku DNS discovery", url=conf.dnsDiscoveryUrl
+
+      var nameServers: seq[TransportAddress]
+      for ip in conf.dnsDiscoveryNameServers:
+        nameServers.add(initTAddress(ip, Port(53))) # Assume all servers use port 53
+
+      let dnsResolver = DnsResolver.new(nameServers)
+
+      proc resolver(domain: string): Future[string] {.async, gcsafe.} =
+        trace "resolving", domain=domain
+        let resolved = await dnsResolver.resolveTxt(domain)
+        return resolved[0] # Use only first answer
       
       var wakuDnsDiscovery = WakuDnsDiscovery.init(conf.dnsDiscoveryUrl,
-                                                   emptyResolver)  # TODO: Add DNS resolver
+                                                   resolver)
       if wakuDnsDiscovery.isOk:
         let discoveredPeers = wakuDnsDiscovery.get().findPeers()
         if discoveredPeers.isOk: