2005-04-02 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	Fix problems when netlink interfaces are renamed (same ifindex used
	for a new interface).  Start cleaning up some problems with the way
	interface names are handled.
	* interface.c: (if_new_intern_ifindex) Remove obsolete function.
	  (if_delete_update) After distributing the interface deletion message,
	  set ifp->ifindex to IFINDEX_INTERNAL.
	  (if_dump_vty) Detect pseudo interface by checking if ifp->ifindex is
	  IFINDEX_INTERNAL.
	  (zebra_interface) Check return code from interface_cmd.func.
	  Do not set internal ifindex values to if_new_intern_ifindex(),
	  since we now use IFINDEX_INTERNAL for all pseudo interfaces.
	* kernel_socket.c: (ifm_read) Fix code and comments to reflect that
	  all internal interfaces now have ifp->ifindex set to IFINDEX_INTERNAL.
        * rt_netlink.c: (set_ifindex) New function used to update ifp->ifindex.
	  Detects interface rename events by checking if that ifindex is already
	  being used.  If it is, delete the old interface before assigning
	  the ifindex to the new interface.
	  (netlink_interface, netlink_link_change) Call set_ifindex to update
	  the ifindex.
	* if.h: Remove define for IFINDEX_INTERNBASE and add define
	  IFINDEX_INTERNAL 0, since all internal (i.e. non-kernel) pseudo-
	  interfaces should have ifindex set to 0.
	  (if_new) Remove function.
	  (if_delete_retain) New function to delete an interface without
	  removing from iflist and freeing the structure.
	  (ifname2ifindex) New function.
	* if.c: (if_new) Remove function (absorb into if_create).
	  (if_create) Replace function if_new with call to calloc.
	  Set ifp->ifindex to IFINDEX_INTERNAL.  Fix off-by-one error
	  in assert to check length of interface name.  Add error message
	  if interface with this name already exists.
	  (if_delete_retain) New function to delete an interface without
	  removing from iflist and freeing the structure.
	  (if_delete) Implement with help of if_delete_retain.
	  (ifindex2ifname) Reimplement using if_lookup_by_index.
	  (ifname2ifindex) New function to complement ifindex2ifname.
	  (interface) The interface command should check the name length
	  and fail with a warning message if it is too long.
	  (no_interface) Fix spelling in warning message.
	  (if_nametoindex) Reimplement using if_lookup_by_name.
	  (if_indextoname, ifaddr_ipv4_lookup) Reimplement using
	  if_lookup_by_index.
	* bgp_zebra.c: (bgp_interface_delete) After deleting, set ifp->ifindex
	  to IFINDEX_INTERNAL.
	* isis_zebra.c: (isis_zebra_if_del) Call if_delete_retain instead
	  of if_delete, since it is generally not safe to remove interface
	  structures.  After deleting, set ifp->ifindex to IFINDEX_INTERNAL.
	  (zebra_interface_if_lookup) Tighten up code.
	* ospf6_zebra.c: (ospf6_zebra_if_del) Previously, this whole function
	  was commented out.  But this is not safe: we should at least update
	  the ifindex when the interface is deleted.  So the new version
	  updates the interface status and sets ifp->ifindex to
	  IFINDEX_INTERNAL.
	  (ospf6_zebra_route_update) Use if_indextoname properly.
	* ospf_vty.c: (show_ip_ospf_interface_sub) Show ifindex and interface
	  flags to help with debugging.
	* ospf_zebra.c: (ospf_interface_delete) After deleting, set ifp->ifindex
	  to IFINDEX_INTERNAL.
	  (zebra_interface_if_lookup) Make function static.  Tighten up code.
	* rip_interface.c: (rip_interface_delete) After deleting, set
	  ifp->ifindex to IFINDEX_INTERNAL.
	* ripng_interface.c: (ripng_interface_delete) After deleting, set
	  ifp->ifindex to IFINDEX_INTERNAL.

1 files changed, 30 insertions, 4 deletions

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index 042ee331..b3b2aab5 100644
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -86,6 +86,33 @@ extern struct zebra_privs_t zserv_privs;
 
 extern u_int32_t nl_rcvbufsize;
 
+/* Note: on netlink systems, there should be a 1-to-1 mapping between interface
+   names and ifindex values. */
+static void
+set_ifindex(struct interface *ifp, unsigned int ifi_index)
+{
+  struct interface *oifp;
+
+  if (((oifp = if_lookup_by_index(ifi_index)) != NULL) && (oifp != ifp))
+    {
+      if (ifi_index == IFINDEX_INTERNAL)
+        zlog_err("Netlink is setting interface %s ifindex to reserved "
+		 "internal value %u", ifp->name, ifi_index);
+      else
+        {
+	  if (IS_ZEBRA_DEBUG_KERNEL)
+	    zlog_debug("interface index %d was renamed from %s to %s",
+	    	       ifi_index, oifp->name, ifp->name);
+	  if (if_is_up(oifp))
+	    zlog_err("interface rename detected on up interface: index %d "
+		     "was renamed from %s to %s, results are uncertain!", 
+	    	     ifi_index, oifp->name, ifp->name);
+	  if_delete_update(oifp);
+        }
+    }
+  ifp->ifindex = ifi_index;
+}
+
 /* Make socket for Linux netlink interface. */
 static int
 netlink_socket (struct nlsock *nl, unsigned long groups)
@@ -504,8 +531,7 @@ netlink_interface (struct sockaddr_nl *snl, struct nlmsghdr *h)
 
   /* Add interface. */
   ifp = if_get_by_name (name);
-
-  ifp->ifindex = ifi->ifi_index;
+  set_ifindex(ifp, ifi->ifi_index);
   ifp->flags = ifi->ifi_flags & 0x0000fffff;
   ifp->mtu6 = ifp->mtu = *(int *) RTA_DATA (tb[IFLA_MTU]);
   ifp->metric = 1;
@@ -981,7 +1007,7 @@ netlink_link_change (struct sockaddr_nl *snl, struct nlmsghdr *h)
           if (ifp == NULL)
             ifp = if_get_by_name (name);
 
-          ifp->ifindex = ifi->ifi_index;
+          set_ifindex(ifp, ifi->ifi_index);
           ifp->flags = ifi->ifi_flags & 0x0000fffff;
           ifp->mtu6 = ifp->mtu = *(int *) RTA_DATA (tb[IFLA_MTU]);
           ifp->metric = 1;
@@ -992,7 +1018,7 @@ netlink_link_change (struct sockaddr_nl *snl, struct nlmsghdr *h)
       else
         {
           /* Interface status change. */
-          ifp->ifindex = ifi->ifi_index;
+          set_ifindex(ifp, ifi->ifi_index);
           ifp->mtu6 = ifp->mtu = *(int *) RTA_DATA (tb[IFLA_MTU]);
           ifp->metric = 1;