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zebra: implement NEXTHOP_FLAG_ONLINK

On Linux, the kernel will only allow for a route to be installed when
its gateway is directly attached according the kernel fib.

There are cases when this restriction by the kernel is too strong, in
those cases, we deploy the RTNH_F_ONLINK netlink flag.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Christian Franke 7 years ago
parent
commit
e8d3d2991f
3 changed files with 18 additions and 1 deletions
  1. 1 0
      zebra/rib.h
  2. 8 1
      zebra/rt_netlink.c
  3. 9 0
      zebra/zebra_vty.c

+ 1 - 0
zebra/rib.h

@@ -253,6 +253,7 @@ struct nexthop
 #define NEXTHOP_FLAG_ACTIVE     (1 << 0) /* This nexthop is alive. */
 #define NEXTHOP_FLAG_FIB        (1 << 1) /* FIB nexthop. */
 #define NEXTHOP_FLAG_RECURSIVE  (1 << 2) /* Recursive nexthop. */
+#define NEXTHOP_FLAG_ONLINK     (1 << 3) /* Nexthop should be installed onlink. */
 
   /* Nexthop address */
   union g_addr gate;

+ 8 - 1
zebra/rt_netlink.c

@@ -1443,8 +1443,11 @@ _netlink_route_build_singlepath(
         int bytelen,
         struct nexthop *nexthop,
         struct nlmsghdr *nlmsg,
+        struct rtmsg *rtmsg,
         size_t req_size)
 {
+  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ONLINK))
+    rtmsg->rtm_flags |= RTNH_F_ONLINK;
   if (nexthop->type == NEXTHOP_TYPE_IPV4
       || nexthop->type == NEXTHOP_TYPE_IPV4_IFINDEX)
     {
@@ -1534,6 +1537,9 @@ _netlink_route_build_multipath(
   rtnh->rtnh_hops = 0;
   rta->rta_len += rtnh->rtnh_len;
 
+  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ONLINK))
+    rtnh->rtnh_flags |= RTNH_F_ONLINK;
+
   if (nexthop->type == NEXTHOP_TYPE_IPV4
       || nexthop->type == NEXTHOP_TYPE_IPV4_IFINDEX)
     {
@@ -1733,7 +1739,8 @@ netlink_route_multipath (int cmd, struct prefix *p, struct rib *rib,
 
               _netlink_route_debug(cmd, p, nexthop, routedesc, family);
               _netlink_route_build_singlepath(routedesc, bytelen,
-                                              nexthop, &req.n, sizeof req);
+                                              nexthop, &req.n, &req.r,
+                                              sizeof req);
 
               if (cmd == RTM_NEWROUTE)
                 SET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

+ 9 - 0
zebra/zebra_vty.c

@@ -615,6 +615,9 @@ vty_show_ip_route_detail (struct vty *vty, struct route_node *rn)
 	  if (! CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
 	    vty_out (vty, " inactive");
 
+	  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ONLINK))
+	    vty_out (vty, " onlink");
+
 	  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
 	    vty_out (vty, " (recursive)");
 
@@ -710,6 +713,9 @@ vty_show_ip_route (struct vty *vty, struct route_node *rn, struct rib *rib)
       if (! CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
 	vty_out (vty, " inactive");
 
+      if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ONLINK))
+	vty_out (vty, " onlink");
+
       if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
 	vty_out (vty, " (recursive)");
 
@@ -1600,6 +1606,9 @@ vty_show_ipv6_route_detail (struct vty *vty, struct route_node *rn)
 	  if (! CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
 	    vty_out (vty, " inactive");
 
+	  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ONLINK))
+	    vty_out (vty, " onlink");
+
 	  if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE))
 	    vty_out (vty, " (recursive)");