zebra: improve interface shutdown behaviour

Linux removes IPv6 addresses when the interface is set down. Those
addresses need to be readded when the interface is set up again.

Also, an interface should not be reactivated from shutdown by configuring
an ip address.

Finally, remove the three-state logic for the shutdown setting as its
sole current use may be mild confusion.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

2 files changed, 49 insertions, 18 deletions

diff --git a/zebra/interface.c b/zebra/interface.c
index 51798ca6..155ee029 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -56,7 +56,7 @@ if_zebra_new_hook (struct interface *ifp)
   zebra_if = XCALLOC (MTYPE_TMP, sizeof (struct zebra_if));
 
   zebra_if->multicast = IF_ZEBRA_MULTICAST_UNSPEC;
-  zebra_if->shutdown = IF_ZEBRA_SHUTDOWN_UNSPEC;
+  zebra_if->shutdown = IF_ZEBRA_SHUTDOWN_OFF;
 
 #ifdef RTADV
   {
@@ -378,6 +378,14 @@ if_add_update (struct interface *ifp)
     {
       SET_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE);
 
+      if (if_data && if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON)
+	{
+	  if (IS_ZEBRA_DEBUG_KERNEL)
+	    zlog_debug ("interface %s index %d is shutdown. Won't wake it up.",
+			ifp->name, ifp->ifindex);
+	  return;
+	}
+
       if_addr_wakeup (ifp);
 
       if (IS_ZEBRA_DEBUG_KERNEL)
@@ -1095,13 +1103,16 @@ DEFUN (shutdown_if,
   struct zebra_if *if_data;
 
   ifp = (struct interface *) vty->index;
-  ret = if_unset_flags (ifp, IFF_UP);
-  if (ret < 0)
+  if (ifp->ifindex != IFINDEX_INTERNAL)
     {
-      vty_out (vty, "Can't shutdown interface%s", VTY_NEWLINE);
-      return CMD_WARNING;
+        ret = if_unset_flags (ifp, IFF_UP);
+        if (ret < 0)
+          {
+            vty_out (vty, "Can't shutdown interface%s", VTY_NEWLINE);
+            return CMD_WARNING;
+          }
+        if_refresh (ifp);
     }
-  if_refresh (ifp);
   if_data = ifp->info;
   if_data->shutdown = IF_ZEBRA_SHUTDOWN_ON;
 
@@ -1119,13 +1130,23 @@ DEFUN (no_shutdown_if,
   struct zebra_if *if_data;
 
   ifp = (struct interface *) vty->index;
-  ret = if_set_flags (ifp, IFF_UP | IFF_RUNNING);
-  if (ret < 0)
+
+  if (ifp->ifindex != IFINDEX_INTERNAL)
     {
-      vty_out (vty, "Can't up interface%s", VTY_NEWLINE);
-      return CMD_WARNING;
+      ret = if_set_flags (ifp, IFF_UP | IFF_RUNNING);
+      if (ret < 0)
+	{
+	  vty_out (vty, "Can't up interface%s", VTY_NEWLINE);
+	  return CMD_WARNING;
+	}
+      if_refresh (ifp);
+
+      /* Some addresses (in particular, IPv6 addresses on Linux) get
+       * removed when the interface goes down. They need to be readded.
+       */
+      if_addr_wakeup(ifp);
     }
-  if_refresh (ifp);
+
   if_data = ifp->info;
   if_data->shutdown = IF_ZEBRA_SHUTDOWN_OFF;
 
@@ -1191,11 +1212,14 @@ ip_address_install (struct vty *vty, struct interface *ifp,
 		    const char *addr_str, const char *peer_str,
 		    const char *label)
 {
+  struct zebra_if *if_data;
   struct prefix_ipv4 cp;
   struct connected *ifc;
   struct prefix_ipv4 *p;
   int ret;
 
+  if_data = ifp->info;
+
   ret = str2prefix_ipv4 (addr_str, &cp);
   if (ret <= 0)
     {
@@ -1237,7 +1261,8 @@ ip_address_install (struct vty *vty, struct interface *ifp,
 
   /* In case of this route need to install kernel. */
   if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_QUEUED)
-      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
+      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE)
+      && !(if_data && if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON))
     {
       /* Some system need to up the interface to set IP address. */
       if (! if_is_up (ifp))
@@ -1371,11 +1396,14 @@ ipv6_address_install (struct vty *vty, struct interface *ifp,
 		      const char *addr_str, const char *peer_str,
 		      const char *label, int secondary)
 {
+  struct zebra_if *if_data;
   struct prefix_ipv6 cp;
   struct connected *ifc;
   struct prefix_ipv6 *p;
   int ret;
 
+  if_data = ifp->info;
+
   ret = str2prefix_ipv6 (addr_str, &cp);
   if (ret <= 0)
     {
@@ -1412,7 +1440,8 @@ ipv6_address_install (struct vty *vty, struct interface *ifp,
 
   /* In case of this route need to install kernel. */
   if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_QUEUED)
-      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
+      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE)
+      && !(if_data && if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON))
     {
       /* Some system need to up the interface to set IP address. */
       if (! if_is_up (ifp))
@@ -1533,6 +1562,12 @@ if_config_write (struct vty *vty)
       vty_out (vty, "interface %s%s", ifp->name,
 	       VTY_NEWLINE);
 
+      if (if_data)
+	{
+	  if (if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON)
+	    vty_out (vty, " shutdown%s", VTY_NEWLINE);
+	}
+
       if (ifp->desc)
 	vty_out (vty, " description %s%s", ifp->desc,
 		 VTY_NEWLINE);
@@ -1565,9 +1600,6 @@ if_config_write (struct vty *vty)
 
       if (if_data)
 	{
-	  if (if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON)
-	    vty_out (vty, " shutdown%s", VTY_NEWLINE);
-
 	  if (if_data->multicast != IF_ZEBRA_MULTICAST_UNSPEC)
 	    vty_out (vty, " %smulticast%s",
 		     if_data->multicast == IF_ZEBRA_MULTICAST_ON ? "" : "no ",
diff --git a/zebra/interface.h b/zebra/interface.h
index 0777a2fa..7a05348c 100644
--- a/zebra/interface.h
+++ b/zebra/interface.h
@@ -34,9 +34,8 @@
 #define IF_ZEBRA_MULTICAST_OFF    2
 
 /* For interface shutdown configuration. */
-#define IF_ZEBRA_SHUTDOWN_UNSPEC 0
+#define IF_ZEBRA_SHUTDOWN_OFF    0
 #define IF_ZEBRA_SHUTDOWN_ON     1
-#define IF_ZEBRA_SHUTDOWN_OFF    2
 
 /* Router advertisement feature. */
 #if (defined(LINUX_IPV6) && (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1)) || defined(KAME)