TUN-6654: Support ICMPv6 on Linux and Darwin

ingress/origin_icmp_proxy.go

@@ -8,6 +8,8 @@ import (
 
 	"github.com/rs/zerolog"
 	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
 
 	"github.com/cloudflare/cloudflared/packet"
 )
@@ -32,8 +34,65 @@ type ICMPProxy interface {
 	Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error
 }
 
-func NewICMPProxy(listenIP netip.Addr, logger *zerolog.Logger) (ICMPProxy, error) {
-	return newICMPProxy(listenIP, logger, funnelIdleTimeout)
+type icmpRouter struct {
+	ipv4Proxy ICMPProxy
+	ipv6Proxy ICMPProxy
+}
+
+// NewICMPProxy doesn't return an error if either ipv4 proxy or ipv6 proxy can be created. The machine might only
+// support one of them
+func NewICMPProxy(logger *zerolog.Logger) (ICMPProxy, error) {
+	// TODO: TUN-6741: don't bind to all interface
+	ipv4Proxy, ipv4Err := newICMPProxy(netip.IPv4Unspecified(), logger, funnelIdleTimeout)
+	ipv6Proxy, ipv6Err := newICMPProxy(netip.IPv6Unspecified(), logger, funnelIdleTimeout)
+	if ipv4Err != nil && ipv6Err != nil {
+		return nil, fmt.Errorf("cannot create ICMPv4 proxy: %v nor ICMPv6 proxy: %v", ipv4Err, ipv6Err)
+	}
+	if ipv4Err != nil {
+		logger.Warn().Err(ipv4Err).Msg("failed to create ICMPv4 proxy, only ICMPv6 proxy is created")
+		ipv4Proxy = nil
+	}
+	if ipv6Err != nil {
+		logger.Warn().Err(ipv6Err).Msg("failed to create ICMPv6 proxy, only ICMPv4 proxy is created")
+		ipv6Proxy = nil
+	}
+	return &icmpRouter{
+		ipv4Proxy: ipv4Proxy,
+		ipv6Proxy: ipv6Proxy,
+	}, nil
+}
+
+func (ir *icmpRouter) Serve(ctx context.Context) error {
+	if ir.ipv4Proxy != nil && ir.ipv6Proxy != nil {
+		errC := make(chan error, 2)
+		go func() {
+			errC <- ir.ipv4Proxy.Serve(ctx)
+		}()
+		go func() {
+			errC <- ir.ipv6Proxy.Serve(ctx)
+		}()
+		return <-errC
+	}
+	if ir.ipv4Proxy != nil {
+		return ir.ipv4Proxy.Serve(ctx)
+	}
+	if ir.ipv6Proxy != nil {
+		return ir.ipv6Proxy.Serve(ctx)
+	}
+	return fmt.Errorf("ICMPv4 proxy and ICMPv6 proxy are both nil")
+}
+
+func (ir *icmpRouter) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error {
+	if pk.Dst.Is4() {
+		if ir.ipv4Proxy != nil {
+			return ir.ipv4Proxy.Request(pk, responder)
+		}
+		return fmt.Errorf("ICMPv4 proxy was not instantiated")
+	}
+	if ir.ipv6Proxy != nil {
+		return ir.ipv6Proxy.Request(pk, responder)
+	}
+	return fmt.Errorf("ICMPv6 proxy was not instantiated")
 }
 
 func getICMPEcho(msg *icmp.Message) (*icmp.Echo, error) {
@@ -43,3 +102,7 @@ func getICMPEcho(msg *icmp.Message) (*icmp.Echo, error) {
 	}
 	return echo, nil
 }
+
+func isEchoReply(msg *icmp.Message) bool {
+	return msg.Type == ipv4.ICMPTypeEchoReply || msg.Type == ipv6.ICMPTypeEchoReply
+}