linux-cp: fix multicast route updates on address add/del

Ensure multicast routes are only added when the first IPv4 address is configured on an interface,
and only removed when the last address is deleted.

This prevents premature removal or redundant addition of multicast routes during address changes.

Type: fix

Change-Id: Id191cd88abfc2c4c354fceec4aaabc030ed938cc
Signed-off-by: Denys Haryachyy <[email protected]>

diff --git a/src/plugins/linux-cp/lcp_router.c b/src/plugins/linux-cp/lcp_router.c
index 4c13c36..342cafc 100644 (file)
--- a/src/plugins/linux-cp/lcp_router.c
+++ b/src/plugins/linux-cp/lcp_router.c
@@ -641,6 +641,51 @@ lcp_router_mk_addr46 (const struct nl_addr *rna, ip46_address_t *ia)
   return (fproto);
 }
 
+static u32
+lcp_router_count_interface_addresses (u32 sw_if_index, u8 address_family)
+{
+  ip_lookup_main_t *lm = NULL;
+  ip_interface_address_t *ia = NULL;
+  u32 count = 0;
+
+  if (address_family == AF_IP4)
+    lm = &ip4_main.lookup_main;
+  else if (address_family == AF_IP6)
+    lm = &ip6_main.lookup_main;
+  else
+    return 0;
+
+  foreach_ip_interface_address (lm, ia, sw_if_index, 1 /* honor unnumbered */,
+                               ({
+                                 (void) ia;
+                                 count++;
+                               }));
+
+  return count;
+}
+
+static void
+lcp_router_update_mroutes_ip4_on_addr_change (u32 sw_if_index, int is_del)
+{
+  u32 count_after;
+
+  count_after = lcp_router_count_interface_addresses (sw_if_index, AF_IP4);
+
+  if ((!is_del && count_after == 1) || (is_del && count_after == 0))
+    lcp_router_ip4_mroutes_add_del (sw_if_index, !is_del);
+}
+
+static void
+lcp_router_update_mroutes_ip6_on_addr_change (u32 sw_if_index, int is_del)
+{
+  u32 count_after;
+
+  count_after = lcp_router_count_interface_addresses (sw_if_index, AF_IP6);
+
+  if ((!is_del && count_after == 1) || (is_del && count_after == 0))
+    lcp_router_ip6_mroutes_add_del (sw_if_index, !is_del);
+}
+
 static void
 lcp_router_link_addr_add_del (struct rtnl_addr *rla, int is_del)
 {
@@ -659,7 +704,7 @@ lcp_router_link_addr_add_del (struct rtnl_addr *rla, int is_del)
          ip4_add_del_interface_address (
            vlib_get_main (), sw_if_index, &ip_addr_v4 (&nh),
            rtnl_addr_get_prefixlen (rla), is_del);
-         lcp_router_ip4_mroutes_add_del (sw_if_index, !is_del);
+         lcp_router_update_mroutes_ip4_on_addr_change (sw_if_index, is_del);
        }
       else if (AF_IP6 == ip_addr_version (&nh))
        {
@@ -675,7 +720,7 @@ lcp_router_link_addr_add_del (struct rtnl_addr *rla, int is_del)
            ip6_add_del_interface_address (
              vlib_get_main (), sw_if_index, &ip_addr_v6 (&nh),
              rtnl_addr_get_prefixlen (rla), is_del);
-         lcp_router_ip6_mroutes_add_del (sw_if_index, !is_del);
+         lcp_router_update_mroutes_ip6_on_addr_change (sw_if_index, is_del);
        }
 
       LCP_ROUTER_DBG ("link-addr: %U %U/%d", format_vnet_sw_if_index_name,