BR: reconnect to dispatcher support

Add logic to support automatic reconnect to dispatcher in case of socket
error.
The feature is enable in the config with the ReconnectToDispatcher
option in the General config section.

go/border/rctrl/BUILD.bazel

@@ -22,5 +22,6 @@ go_library(
         "//go/lib/log:go_default_library",
         "//go/lib/snet:go_default_library",
         "//go/lib/sock/reliable:go_default_library",
+        "//go/lib/sock/reliable/reconnect:go_default_library",
     ],
 )

go/border/rctrl/ctrl.go

@@ -28,6 +28,7 @@ import (
 	"github.com/scionproto/scion/go/lib/log"
 	"github.com/scionproto/scion/go/lib/snet"
 	"github.com/scionproto/scion/go/lib/sock/reliable"
+	"github.com/scionproto/scion/go/lib/sock/reliable/reconnect"
 )
 
 const (
@@ -40,21 +41,28 @@ var (
 	logger   log.Logger
 )
 
-func Control(sRevInfoQ chan rpkt.RawSRevCallbackArgs) {
+func Control(sRevInfoQ chan rpkt.RawSRevCallbackArgs, dispatcherReconnect bool) {
 	var err error
 	logger = log.New("Part", "Control")
 	ctx := rctx.Get()
 	ia = ctx.Conf.IA
-	if err = snet.Init(ia, "", reliable.NewDispatcherService("")); err != nil {
-		fatal.Fatal(common.NewBasicError("Initializing SNET", err))
+	dispatcherService := reliable.NewDispatcherService("")
+	if dispatcherReconnect {
+		dispatcherService = reconnect.NewDispatcherService(dispatcherService)
 	}
+	scionNetwork := snet.NewCustomNetworkWithPR(ia,
+		&snet.DefaultPacketDispatcherService{
+			Dispatcher: dispatcherService,
+		},
+		nil,
+	)
 	ctrlAddr := ctx.Conf.BR.CtrlAddrs
 	pub := &snet.Addr{IA: ia, Host: ctrlAddr.IPv4.PublicAddr()}
 	bind := &snet.Addr{IA: ia, Host: ctrlAddr.IPv4.BindAddr()}
 	if bind.Host == nil {
 		bind = nil
 	}
-	snetConn, err = snet.ListenSCIONWithBindSVC("udp4", pub, bind, addr.SvcNone)
+	snetConn, err = scionNetwork.ListenSCIONWithBindSVC("udp4", pub, bind, addr.SvcNone, 0)
 	if err != nil {
 		fatal.Fatal(common.NewBasicError("Listening on address", err, "addr", ctrlAddr))
 	}

go/border/router.go

@@ -72,7 +72,7 @@ func (r *Router) Start() {
 	}()
 	go func() {
 		defer log.LogPanicAndExit()
-		rctrl.Control(r.sRevInfoQ)
+		rctrl.Control(r.sRevInfoQ, cfg.General.ReconnectToDispatcher)
 	}()
 	if err := r.startDiscovery(); err != nil {
 		fatal.Fatal(common.NewBasicError("Unable to start discovery", err))