For ICMP, only use RawConn for the Don't Fagment case (#329)

Signed-off-by: Arsène von Wyss <avw@gmx.ch>

diff --git a/prober/icmp.go b/prober/icmp.go
index 687ab6cbf2672de6c008e8d7bc12bea4b6d51bd5..82f460f10518ce94b6de3b8fcc912a1672785e4d 100644 (file)
--- a/prober/icmp.go
+++ b/prober/icmp.go
@@ -46,7 +46,6 @@ func getICMPSequence() uint16 {
 func ProbeICMP(ctx context.Context, target string, module config.Module, registry *prometheus.Registry, logger log.Logger) (success bool) {
        var (
                socket      net.PacketConn
-               socket6     *ipv6.PacketConn
                requestType icmp.Type
                replyType   icmp.Type
        )
@@ -73,30 +72,39 @@ func ProbeICMP(ctx context.Context, target string, module config.Module, registr
                requestType = ipv6.ICMPTypeEchoRequest
                replyType = ipv6.ICMPTypeEchoReply
 
-               icmpConn, err := icmp.ListenPacket("ip6:ipv6-icmp", "::")
+               if srcIP == nil {
+                       srcIP = net.ParseIP("::")
+               }
+               icmpConn, err := icmp.ListenPacket("ip6:ipv6-icmp", srcIP.String())
                if err != nil {
                        level.Error(logger).Log("msg", "Error listening to socket", "err", err)
                        return
                }
 
                socket = icmpConn
-               socket6 = icmpConn.IPv6PacketConn()
        } else {
                requestType = ipv4.ICMPTypeEcho
                replyType = ipv4.ICMPTypeEchoReply
 
-               s, err := net.ListenPacket("ip4:icmp", "0.0.0.0")
+               if srcIP == nil {
+                       srcIP = net.ParseIP("0.0.0.0")
+               }
+               icmpConn, err := net.ListenPacket("ip4:icmp", srcIP.String())
                if err != nil {
                        level.Error(logger).Log("msg", "Error listening to socket", "err", err)
                        return
                }
 
-               rc, err := ipv4.NewRawConn(s)
-               if err != nil {
-                       level.Error(logger).Log("msg", "Error creating raw connection", "err", err)
-                       return
+               if module.ICMP.DontFragment {
+                       rc, err := ipv4.NewRawConn(icmpConn)
+                       if err != nil {
+                               level.Error(logger).Log("msg", "Error creating raw connection", "err", err)
+                               return
+                       }
+                       socket = &v4Conn{c: rc, df: true}
+               } else {
+                       socket = icmpConn
                }
-               socket = &v4Conn{c: rc, df: module.ICMP.DontFragment, src: srcIP}
        }
 
        defer socket.Close()
@@ -127,18 +135,9 @@ func ProbeICMP(ctx context.Context, target string, module config.Module, registr
                return
        }
        level.Info(logger).Log("msg", "Writing out packet")
-       if socket6 != nil && srcIP != nil {
-               // Also set source address for IPv6.
-               cm := &ipv6.ControlMessage{Src: srcIP}
-               if _, err = socket6.WriteTo(wb, cm, ip); err != nil {
-                       level.Error(logger).Log("msg", "Error writing to IPv6 socket", "err", err)
-                       return
-               }
-       } else {
-               if _, err = socket.WriteTo(wb, ip); err != nil {
-                       level.Warn(logger).Log("msg", "Error writing to socket", "err", err)
-                       return
-               }
+       if _, err = socket.WriteTo(wb, ip); err != nil {
+               level.Warn(logger).Log("msg", "Error writing to socket", "err", err)
+               return
        }
 
        // Reply should be the same except for the message type.