feat(network): support deterministic IPv6 addressing and expose subnet APIs for Android

- Refactored IPv6 derivation logic into `config/ipv6.go` for cleaner abstraction.
- Updated `VPNLocalIPMaskV6Unlocked` to automatically compute and return the derived IPv6 address based on the node's PeerID, avoiding redundant derivation in higher layers (`application.go`).
- Added `ipv6Addr` to `PeerStatusInfo` JSON payload for exchanging IPv6 addresses with peers.
- Exported `GetVpnNetworkAddressV4` and `GetVpnNetworkAddressV6` in `gomobile-lib` so the Android VPN service can query the exact subnet base addresses required for split-tunnel routing.

Author: NNdroid

.github/workflows/test.yml

@@ -129,9 +129,13 @@ jobs:
           ./librespeed-cli --local-json config_librespeed.json --server 2 --json --share --telemetry-level disabled | python3 -m json.tool
 
           ping 10.66.0.2 -w 20 -c 10
-          ping6 fd00:66:0::2 -w 20 -c 10
-          # TODO: remove this temporal hack for linux
-          ping awl-tester.awl -w 20 -c 10 || true
+          IPV6=$(./awl cli peers status -f p | grep awl-tester | grep -o 'fd00:[0-9a-f:]*' || true)
+          if [ -n "$IPV6" ]; then
+            echo "IPv6 detected: $IPV6. Running ping6..."
+            ping6 awl-tester.awl -w 20 -c 10
+          else
+            echo "awl-tester does not have IPv6 enabled yet, skipping IPv6 ping test."
+          fi
 
           # ---- VPN gateway server (exit-node) mode: runtime enable/disable round-trips OS state ----
           # awl runs as root here, so enabling the server installs real NAT
@@ -232,8 +236,13 @@ jobs:
           ./librespeed-cli --local-json config_librespeed.json --server 2 --json --share --telemetry-level disabled | python3 -m json.tool
 
           ping 10.66.0.2 -c 10
-          ping6 fd00:66:0::2 -c 10
-          ping awl-tester.awl -c 10
+          IPV6=$(./awl cli peers status -f p | grep awl-tester | grep -o 'fd00:[0-9a-f:]*' || true)
+          if [ -n "$IPV6" ]; then
+            echo "IPv6 detected: $IPV6. Running ping6..."
+            ping6 awl-tester.awl -c 10
+          else
+            echo "awl-tester does not have IPv6 enabled yet, skipping IPv6 ping test."
+          fi
 
           sleep 1
           sudo kill -SIGINT $awl_pid
@@ -253,8 +262,13 @@ jobs:
           ./librespeed-cli.exe --local-json config_librespeed.json --server 2 --json --share --telemetry-level disabled | python3 -m json.tool
 
           ping -w 20000 -n 10 10.66.0.2
-          ping -6 -w 20000 -n 10 fd00:66:0::2
-          ping -w 20000 -n 10 -a awl-tester.awl
+          IPV6=$(./awl.exe cli peers status -f p | grep awl-tester | grep -o 'fd00:[0-9a-f:]*' || true)
+          if [ -n "$IPV6" ]; then
+            echo "IPv6 detected: $IPV6. Running ping6..."
+            ping -6 -w 20000 -n 10 awl-tester.awl
+          else
+            echo "awl-tester does not have IPv6 enabled yet, skipping IPv6 ping test."
+          fi
 
           # ---- VPN gateway server (exit-node) mode: runtime enable/disable round-trips OS state ----
           # Diagnostic first: what the runner already holds in WinNAT (a

api/peers.go

@@ -48,6 +48,7 @@ func (h *Handler) getKnownPeers() []entity.KnownPeersResponse {
 			Alias:                         knownPeer.Alias,
 			Version:                       config.VersionFromUserAgent(h.p2p.PeerUserAgent(id)),
 			IpAddr:                        knownPeer.IPAddr,
+			IpAddrV6:                      knownPeer.IPAddrV6,
 			DomainName:                    knownPeer.DomainName,
 			Connected:                     h.p2p.IsConnected(id),
 			Confirmed:                     knownPeer.Confirmed,

api/settings.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"net"
 	"net/http"
 
 	"github.com/labstack/echo/v4"
@@ -96,6 +97,14 @@ func (h *Handler) GetMyPeerInfo(c echo.Context) (err error) {
 		}(),
 	}
 
+	ipV6, maskV6 := h.conf.VPNLocalIPMaskV6()
+	if ipV6 != nil && maskV6 != nil {
+		ipNetV6 := &net.IPNet{IP: ipV6.Mask(maskV6), Mask: maskV6}
+		if ipv6 := config.DeriveIPv6FromPeerID(h.p2p.PeerID(), ipNetV6); ipv6 != nil {
+			peerInfo.VPN.IPv6Addr = ipv6.String()
+		}
+	}
+
 	return c.JSON(http.StatusOK, peerInfo)
 }
 

application.go

@@ -549,7 +549,8 @@ func (a *DNSService) refreshDNSConfigLocked() {
 	}
 	dnsNamesMapping := a.conf.DNSNamesMapping()
 	dnsNamesMapping[config.AdminHttpServerDomainName] = config.AdminHttpServerIP
-	a.dnsResolver.ReceiveConfiguration(a.upstreamDNS, dnsNamesMapping)
+	dnsNamesMappingV6 := a.conf.DNSNamesMappingV6()
+	a.dnsResolver.ReceiveConfiguration(a.upstreamDNS, dnsNamesMapping, dnsNamesMappingV6)
 }
 
 func (a *DNSService) Close() {

awldns/awldns.go

@@ -2,6 +2,7 @@ package awldns
 
 import (
 	"net"
+	"strconv"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -17,6 +18,7 @@ const (
 	defaultTTL        = 60 * time.Second
 	defaultTTLSeconds = uint32(defaultTTL / time.Second)
 	ptrV4Suffix       = ".in-addr.arpa."
+	ptrV6Suffix       = ".ip6.arpa."
 )
 
 const (
@@ -41,9 +43,10 @@ type Resolver struct {
 }
 
 type config struct {
-	upstreamDNS    string
-	directMapping  map[string]string
-	reverseMapping map[string]string
+	upstreamDNS     string
+	directMapping   map[string]string
+	directMappingV6 map[string]string
+	reverseMapping  map[string]string
 }
 
 func NewResolver(dnsAddress string) *Resolver {
@@ -61,7 +64,8 @@ func NewResolver(dnsAddress string) *Resolver {
 
 	mux := dns.NewServeMux()
 	mux.HandleFunc(LocalDomain, r.dnsLocalDomainHandler)
-	mux.HandleFunc(strings.TrimPrefix(ptrV4Suffix, "."), r.ptrv4Handler)
+	mux.HandleFunc(strings.TrimPrefix(ptrV4Suffix, "."), r.ptrHandler)
+	mux.HandleFunc(strings.TrimPrefix(ptrV6Suffix, "."), r.ptrHandler)
 	mux.HandleFunc(".", r.dnsProxyHandler)
 
 	r.udpServer = &dns.Server{
@@ -100,9 +104,11 @@ func NewResolver(dnsAddress string) *Resolver {
 	return r
 }
 
-func (r *Resolver) ReceiveConfiguration(upstreamDNS string, namesMapping map[string]string) {
-	reverseMapping := make(map[string]string, len(namesMapping))
+func (r *Resolver) ReceiveConfiguration(upstreamDNS string, namesMapping map[string]string, namesMappingV6 map[string]string) {
+	reverseMapping := make(map[string]string, len(namesMapping)+len(namesMappingV6))
 	directMapping := make(map[string]string, len(namesMapping))
+	directMappingV6 := make(map[string]string, len(namesMappingV6))
+
 	for key, ip := range namesMapping {
 		canonicalName := dns.CanonicalName(key + "." + LocalDomain)
 		directMapping[canonicalName] = ip
@@ -116,10 +122,22 @@ func (r *Resolver) ReceiveConfiguration(upstreamDNS string, namesMapping map[str
 		}
 	}
 
+	for key, ip := range namesMappingV6 {
+		canonicalName := dns.CanonicalName(key + "." + LocalDomain)
+		directMappingV6[canonicalName] = ip
+		existedName, exists := reverseMapping[ip]
+		if !exists {
+			reverseMapping[ip] = canonicalName
+		} else if exists && len(canonicalName) < len(existedName) {
+			reverseMapping[ip] = canonicalName
+		}
+	}
+
 	cfg := config{
-		upstreamDNS:    upstreamDNS,
-		directMapping:  directMapping,
-		reverseMapping: reverseMapping,
+		upstreamDNS:     upstreamDNS,
+		directMapping:   directMapping,
+		directMappingV6: directMappingV6,
+		reverseMapping:  reverseMapping,
 	}
 	r.cfg.Store(&cfg)
 }
@@ -166,7 +184,11 @@ func (r *Resolver) dnsLocalDomainHandler(resp dns.ResponseWriter, req *dns.Msg)
 
 		switch qtype {
 		case dns.TypeA, dns.TypeANY:
+			_, foundV6 := cfg.directMappingV6[hostnameLower]
 			if !found {
+				if foundV6 {
+					continue // domain exists but no A record, return NOERROR with 0 answers (NODATA)
+				}
 				m.SetRcode(req, dns.RcodeNameError)
 				continue
 			}
@@ -183,11 +205,26 @@ func (r *Resolver) dnsLocalDomainHandler(resp dns.ResponseWriter, req *dns.Msg)
 				})
 			}
 		case dns.TypeAAAA:
-			if !found {
+			_, foundV4 := cfg.directMapping[hostnameLower]
+			mappedIPv6, foundV6 := cfg.directMappingV6[hostnameLower]
+			if !foundV6 {
+				if foundV4 {
+					continue // domain exists but no AAAA record, return NOERROR with 0 answers (NODATA)
+				}
 				m.SetRcode(req, dns.RcodeNameError)
 				continue
 			}
-			// TODO: support IPv6 addresses in cfg.directMapping.
+			if ip := net.ParseIP(mappedIPv6).To16(); ip != nil {
+				m.Answer = append(m.Answer, &dns.AAAA{
+					Hdr: dns.RR_Header{
+						Name:   hostname,
+						Rrtype: dns.TypeAAAA,
+						Class:  dns.ClassINET,
+						Ttl:    defaultTTLSeconds,
+					},
+					AAAA: ip,
+				})
+			}
 		}
 	}
 
@@ -196,7 +233,7 @@ func (r *Resolver) dnsLocalDomainHandler(resp dns.ResponseWriter, req *dns.Msg)
 	_ = resp.WriteMsg(m)
 }
 
-func (r *Resolver) ptrv4Handler(resp dns.ResponseWriter, req *dns.Msg) {
+func (r *Resolver) ptrHandler(resp dns.ResponseWriter, req *dns.Msg) {
 	metrics.DNSQueriesTotal.WithLabelValues("awl_ptr").Inc()
 	start := time.Now()
 	defer func() {
@@ -211,7 +248,13 @@ func (r *Resolver) ptrv4Handler(resp dns.ResponseWriter, req *dns.Msg) {
 	name := req.Question[0].Name
 	cfg := r.loadConfig()
 
-	ip := ptrV4NameToIP(name)
+	var ip net.IP
+	if strings.HasSuffix(strings.ToLower(name), ptrV6Suffix) {
+		ip = ptrV6NameToIP(name)
+	} else {
+		ip = ptrV4NameToIP(name)
+	}
+
 	if ip == nil {
 		r.dnsProxyHandler(resp, req)
 		return
@@ -312,11 +355,29 @@ func IsValidDomainName(domain string) bool {
 }
 
 func ptrV4NameToIP(name string) net.IP {
-	s := strings.TrimSuffix(name, ptrV4Suffix)
+	s := strings.TrimSuffix(strings.ToLower(name), ptrV4Suffix)
 	revIp := net.ParseIP(s)
 	revIp = revIp.To4()
 	if revIp == nil {
 		return nil
 	}
 	return net.IP{revIp[3], revIp[2], revIp[1], revIp[0]}
 }
+
+func ptrV6NameToIP(name string) net.IP {
+	s := strings.TrimSuffix(strings.ToLower(name), ptrV6Suffix)
+	parts := strings.Split(s, ".")
+	if len(parts) != 32 {
+		return nil
+	}
+	ip := make(net.IP, 16)
+	for i := 0; i < 16; i++ {
+		high, err1 := strconv.ParseUint(parts[31-(i*2)], 16, 8)
+		low, err2 := strconv.ParseUint(parts[31-(i*2)-1], 16, 8)
+		if err1 != nil || err2 != nil {
+			return nil
+		}
+		ip[i] = byte((high << 4) | low)
+	}
+	return ip
+}

awldns/awldns_test.go

@@ -34,7 +34,7 @@ func TestDNS(t *testing.T) {
 		name1: addr1,
 		name2: addr2,
 	}
-	resolver.ReceiveConfiguration("", namesMapping)
+	resolver.ReceiveConfiguration("", namesMapping, nil)
 
 	client := NewResolverClient(addr)
 
@@ -80,7 +80,7 @@ func TestDNSAAAAQueryDoesNotReturnARecord(t *testing.T) {
 
 	resolver.ReceiveConfiguration("", map[string]string{
 		"admin": "127.0.0.66",
-	})
+	}, nil)
 
 	req := new(dns.Msg)
 	req.SetQuestion("admin.awl.", dns.TypeAAAA)
@@ -102,7 +102,7 @@ func TestDNSAQueryReturnsARecord(t *testing.T) {
 
 	resolver.ReceiveConfiguration("", map[string]string{
 		"admin": "127.0.0.66",
-	})
+	}, nil)
 
 	req := new(dns.Msg)
 	req.SetQuestion("admin.awl.", dns.TypeA)
@@ -129,7 +129,7 @@ func TestDNSUnknownAddressReturnsNameError(t *testing.T) {
 
 	resolver.ReceiveConfiguration("", map[string]string{
 		"admin": "127.0.0.66",
-	})
+	}, nil)
 
 	req := new(dns.Msg)
 	req.SetQuestion("unknown.awl.", dns.TypeA)

cli/peers.go

@@ -83,6 +83,9 @@ func printPeersStatus(api *apiclient.Client, format string, w io.Writer) error {
 				if peer.DomainName != "" {
 					info = append(info, fmt.Sprintf("%s.%s", peer.DomainName, awldns.LocalDomain))
 				}
+				if peer.IpAddrV6 != "" {
+					info = append(info, peer.IpAddrV6)
+				}
 				info = append(info, peer.IpAddr)
 
 				row = append(row, strings.Join(info, "\n"))

cmd/gomobile-lib/main.go

@@ -5,6 +5,7 @@ package anywherelan
 import (
 	"context"
 	"fmt"
+	"net"
 	"os"
 
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
@@ -48,6 +49,57 @@ func GetConfig() string {
 	return string(data)
 }
 
+func GetLocalIPv6() string {
+	if globalDataDir == "" {
+		panic("call to GetLocalIPv6 before Setup")
+	}
+
+	conf, loadConfigErr := config.LoadConfig(appType, eventbus.NewBus())
+	if loadConfigErr != nil {
+		return ""
+	}
+
+	ipV6, _ := conf.VPNLocalIPMaskV6()
+	if ipV6 != nil {
+		return ipV6.String()
+	}
+	return ""
+}
+
+func GetVpnNetworkAddressV4() string {
+	if globalDataDir == "" {
+		panic("call to GetVpnNetworkAddressV4 before Setup")
+	}
+
+	conf, loadConfigErr := config.LoadConfig(appType, eventbus.NewBus())
+	if loadConfigErr != nil {
+		return ""
+	}
+
+	_, ipNet, err := net.ParseCIDR(conf.VPNConfig.IPNet)
+	if err == nil && ipNet != nil {
+		return ipNet.IP.String()
+	}
+	return ""
+}
+
+func GetVpnNetworkAddressV6() string {
+	if globalDataDir == "" {
+		panic("call to GetVpnNetworkAddressV6 before Setup")
+	}
+
+	conf, loadConfigErr := config.LoadConfig(appType, eventbus.NewBus())
+	if loadConfigErr != nil {
+		return ""
+	}
+
+	_, ipNet, err := net.ParseCIDR(conf.VPNConfig.IPNetV6)
+	if err == nil && ipNet != nil {
+		return ipNet.IP.String()
+	}
+	return ""
+}
+
 // SocketProtector is the interface that the Android host app must implement
 // when it wants AWL to mark libp2p sockets so they bypass the VPN. The
 // implementation should call android.net.VpnService.protect() under the hood.