Improve logic

go.mod

@@ -1,8 +1,8 @@
 module pndpd
 
-go 1.20
+go 1.22.5
 
 require (
-	golang.org/x/net v0.9.0
-	golang.org/x/sys v0.7.0
+	golang.org/x/net v0.27.0
+	golang.org/x/sys v0.22.0
 )

go.sum

@@ -1,4 +1,4 @@
-golang.org/x/net v0.9.0 h1:aWJ/m6xSmxWBx+V0XRHTlrYrPG56jKsLdTFmsSsCzOM=
-golang.org/x/net v0.9.0/go.mod h1:d48xBJpPfHeWQsugry2m+kC02ZBRGRgulfHnEXEuWns=
-golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
-golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/net v0.27.0 h1:5K3Njcw06/l2y9vpGCSdcxWOYHOUk3dVNGDXN+FvAys=
+golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE=
+golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
+golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

pndp/interface.go

@@ -74,6 +74,7 @@ func setPromisc(fd int, iface string, enable bool, withInterfaceFlags bool) {
 	iFace, err := net.InterfaceByName(iface)
 	if err != nil {
 		showFatalError(err.Error())
+		return
 	}
 
 	mReq := unix.PacketMreq{
@@ -95,34 +96,44 @@ func setPromisc(fd int, iface string, enable bool, withInterfaceFlags bool) {
 	// ---------------------------------------------------------------------
 }
 
-func selectSourceIP(iface *net.Interface) []byte {
-	var _, ulaSpace, _ = net.ParseCIDR("fc00::/7")
-	var result = emptyIpv6
-	ifaceaddrs, err := iface.Addrs()
+func selectSourceIP(iface *net.Interface) (gua []byte, ula []byte) {
+	gua = emptyIpv6
+	ula = emptyIpv6
+	interfaceAddresses, err := iface.Addrs()
 	if err != nil {
-		return result
+		return gua, ula
 	}
 
-	for _, n := range ifaceaddrs {
-		tip, _, err := net.ParseCIDR(n.String())
+	var haveUla = false
+	var haveGua = false
+	for _, n := range interfaceAddresses {
+		if haveGua && haveUla {
+			break
+		}
+		testIP, _, err := net.ParseCIDR(n.String())
 		if err != nil {
 			break
 		}
-		var haveUla = false
-		if isIpv6(tip.String()) {
-			if tip.IsGlobalUnicast() {
-				haveUla = true
-				result = tip
-
-				if !ulaSpace.Contains(tip) {
-					break
+		if isIpv6(testIP.String()) {
+			if testIP.IsGlobalUnicast() {
+				if !ulaSpace.Contains(testIP) {
+					haveGua = true
+					gua = testIP
+				} else {
+					haveUla = true
+					ula = testIP
+				}
+			} else if testIP.IsLinkLocalUnicast() {
+				if !haveUla {
+					ula = testIP
+				}
+				if !haveGua {
+					gua = testIP
 				}
-			} else if tip.IsLinkLocalUnicast() && !haveUla {
-				result = tip
 			}
 		}
 	}
-	return result
+	return gua, ula
 }
 
 func getInterfaceNetworkList(iface *net.Interface) []*net.IPNet {

pndp/interfaceMon.go

@@ -60,13 +60,14 @@ func getUpdates() {
 			continue
 		}
 
-		srcIP := selectSourceIP(iface)
+		srcIP, srcIPUla := selectSourceIP(iface)
 		monMutex.Lock()
 
 		for i := range monInterfaceList {
 			if monInterfaceList[i].iface.Name == iface.Name {
 				oldMonIface := monInterfaceList[i]
 				oldMonIface.sourceIP = srcIP
+				oldMonIface.sourceIPULA = srcIPUla
 				if oldMonIface.autosense {
 					oldMonIface.networks = getInterfaceNetworkList(iface)
 				}
@@ -78,11 +79,12 @@ func getUpdates() {
 }
 
 type monInterface struct {
-	addCount  int
-	sourceIP  []byte //TODO ULA
-	networks  []*net.IPNet
-	iface     *net.Interface
-	autosense bool
+	addCount    int
+	sourceIP    []byte
+	sourceIPULA []byte
+	networks    []*net.IPNet
+	iface       *net.Interface
+	autosense   bool
 }
 
 var (
@@ -100,6 +102,7 @@ func addInterfaceToMon(iface string, autosense bool) {
 	niface, err := net.InterfaceByName(iface)
 	if err != nil {
 		showFatalError(err.Error())
+		return
 	}
 
 	for i := range monInterfaceList {
@@ -117,7 +120,7 @@ func addInterfaceToMon(iface string, autosense bool) {
 		autosense: autosense,
 		iface:     niface,
 	}
-	newMonIface.sourceIP = selectSourceIP(niface)
+	newMonIface.sourceIP, newMonIface.sourceIPULA = selectSourceIP(niface)
 	newMonIface.networks = getInterfaceNetworkList(niface)
 
 	monInterfaceList = append(monInterfaceList, newMonIface)
@@ -132,6 +135,7 @@ func removeInterfaceFromMon(iface string) {
 	niface, err := net.InterfaceByName(iface)
 	if err != nil {
 		showFatalError(err.Error())
+		return
 	}
 	for i := range monInterfaceList {
 		if monInterfaceList[i].iface.Name == niface.Name {

pndp/netlink.go

@@ -42,7 +42,7 @@ func newNetlinkSocket(protocol int, multicastGroups ...uint) (*netlinkSocket, er
 	socket.lsa.Family = unix.AF_NETLINK
 
 	for _, g := range multicastGroups {
-		socket.lsa.Groups |= (1 << (g - 1))
+		socket.lsa.Groups |= 1 << (g - 1)
 	}
 
 	err = unix.Bind(fd, &socket.lsa)

pndp/packet.go

@@ -129,7 +129,7 @@ func calculateChecksum(h *ipv6Header, payload []byte) uint16 {
 }
 
 func checksumAddition(b []byte, buf uint16) uint16 {
-	var sum uint32 = uint32(buf)
+	var sum = uint32(buf)
 	cv := len(b) - 1
 	for i := 0; i < cv; i += 2 {
 		sum += uint32(uint16(b[i])<<8 | uint16(b[i+1]))

pndp/responder.go

@@ -44,8 +44,6 @@ func respond(iface string, requests chan *ndpRequest, respondType ndpType, ndpQu
 		showFatalError(err.Error())
 	}
 
-	var selectedSelfSourceIP = emptyIpv6
-
 	for {
 		var req *ndpRequest
 		if (ndpQuestionChan == nil && respondType == ndp_ADV) || (ndpQuestionChan != nil && respondType == ndp_SOL) {
@@ -80,7 +78,6 @@ func respond(iface string, requests chan *ndpRequest, respondType ndpType, ndpQu
 			continue
 		}
 
-		selectedSelfSourceIP = getInterfaceInfo(respondIface).sourceIP
 		// Auto-sense
 		if autoSense != "" {
 			filter = getInterfaceInfo(autoiface).networks
@@ -100,9 +97,17 @@ func respond(iface string, requests chan *ndpRequest, respondType ndpType, ndpQu
 			}
 		}
 
+		intInfo := getInterfaceInfo(respondIface)
+		var selectedSelfSourceIPGua = intInfo.sourceIP
+		var selectedSelfSourceIPUla = intInfo.sourceIPULA
+		var selectedSelfSourceIP = selectedSelfSourceIPGua
+		if ulaSpace.Contains(req.answeringForIP) {
+			selectedSelfSourceIP = selectedSelfSourceIPUla
+		}
+
 		if req.sourceIface == iface {
 			slog.Debug("Sending packet", "type", respondType, "dest", ipValue{req.dstIP}, "interface", respondIface.Name)
-			sendNDPPacket(fd, selectedSelfSourceIP, req.srcIP, req.answeringForIP, respondIface.HardwareAddr, respondType)
+			sendNDPPacket(fd, req.dstIP, req.srcIP, req.answeringForIP, respondIface.HardwareAddr, respondType)
 		} else {
 			if respondType == ndp_ADV {
 				if !bytes.Equal(req.dstIP, allNodesMulticastIPv6) { // Skip in case of unsolicited advertisement
@@ -125,6 +130,7 @@ func respond(iface string, requests chan *ndpRequest, respondType ndpType, ndpQu
 				}
 			}
 			slog.Debug("Sending packet", "type", respondType, "dest", ipValue{req.dstIP}, "interface", respondIface.Name)
+
 			sendNDPPacket(fd, selectedSelfSourceIP, req.dstIP, req.answeringForIP, respondIface.HardwareAddr, respondType)
 		}
 	}
@@ -145,11 +151,9 @@ func sendNDPPacket(fd int, ownIP []byte, dstIP []byte, ndpTargetIP []byte, ndpTa
 	var t [16]byte
 	copy(t[:], dstIP)
 
-	d := syscall.SockaddrInet6{
-		Port: 0,
+	err = syscall.Sendto(fd, packet, 0, &syscall.SockaddrInet6{
 		Addr: t,
-	}
-	err = syscall.Sendto(fd, packet, 0, &d)
+	})
 	if err != nil {
 		slog.Error("Error sending packet", err)
 	}

pndp/util.go

@@ -3,6 +3,7 @@ package pndp
 import (
 	"fmt"
 	"log/slog"
+	"net"
 	"net/netip"
 	"os"
 )
@@ -44,3 +45,5 @@ func (v macValue) LogValue() slog.Value {
 // Htons Convert a uint16 to host byte order (big endian)
 func htons(v uint16) int      { return int(htons16(v)) }
 func htons16(v uint16) uint16 { return (v << 8) | (v >> 8) }
+
+var _, ulaSpace, _ = net.ParseCIDR("fc00::/7")

pndp_test.sh

@@ -13,6 +13,7 @@ ip netns exec pndpd-i sysctl -w net.ipv6.conf.all.forwarding=1
 # Provider bridge
 ip -netns pndpd-p link add br0 type bridge
 ip -netns pndpd-p addr add fd00::/62 dev br0
+ip -netns pndpd-p addr add 2001:db8::/62 dev br0
 ip -netns pndpd-p link set dev br0 address 00:00:00:00:00:01 # Predictable link-local
 ip -netns pndpd-p link set up dev br0
 
@@ -23,12 +24,14 @@ ip -netns pndpd-p link set veth-c0 master br0
 
 ip -netns pndpd-p link set veth-p netns pndpd-c
 ip -netns pndpd-c addr add fd00:0:0:1::/128 dev veth-p
+ip -netns pndpd-c addr add 2001:db8:0:1::/128 dev veth-p
 ip -netns pndpd-c link set up dev veth-p
 ip -netns pndpd-c route add default via fe80::200:ff:fe00:1 dev veth-p
 
 # Bridge on client 0
 ip -netns pndpd-c link add br0 type bridge
 ip -netns pndpd-c addr add fd00:0:0:1::/64 dev br0
+ip -netns pndpd-c addr add 2001:db8:0:1::/64 dev br0
 ip -netns pndpd-c link set dev br0 address 00:00:00:00:00:02
 ip -netns pndpd-c link set up dev br0
 
@@ -39,6 +42,7 @@ ip -netns pndpd-c link set veth-i0 master br0
 
 ip -netns pndpd-c link set veth-c netns pndpd-i
 ip -netns pndpd-i addr add fd00:0:0:1::100/64 dev veth-c
+ip -netns pndpd-i addr add 2001:db8:0:1::100/64 dev veth-c
 ip -netns pndpd-i link set up dev veth-c
 ip -netns pndpd-i route add default via fd00:0:0:1:: dev veth-c
 
@@ -49,6 +53,7 @@ sleep 2
 
 # Perform tests
 ip netns exec pndpd-p ping -c 5 -w 10 fd00:0:0:1::100
+ip netns exec pndpd-p ping -c 5 -w 10 2001:db8:0:1::100
 
 kill -n 2 "$PID"
 wait