VPP-719: Accept ARP replies from VRRP hw addr

[vpp.git] / src / vnet / ethernet / arp.c

diff --git a/src/vnet/ethernet/arp.c b/src/vnet/ethernet/arp.c
index bfcd357..f44cb59 100644 (file)
--- a/src/vnet/ethernet/arp.c
+++ b/src/vnet/ethernet/arp.c
@@ -107,6 +107,8 @@ typedef struct
 #define ETHERNET_ARP_ARGS_POPULATE  (1<<2)
 } vnet_arp_set_ip4_over_ethernet_rpc_args_t;
 
+static const u8 vrrp_prefix[] = { 0x00, 0x00, 0x5E, 0x00, 0x01 };
+
 static void
 set_ip4_over_ethernet_rpc_callback (vnet_arp_set_ip4_over_ethernet_rpc_args_t
                                    * a);
@@ -991,7 +993,7 @@ arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
          ethernet_header_t *eth0;
          ip4_address_t *if_addr0, proxy_src;
          u32 pi0, error0, next0, sw_if_index0, conn_sw_if_index0, fib_index0;
-         u8 is_request0, dst_is_local0, is_unnum0;
+         u8 is_request0, dst_is_local0, is_unnum0, is_vrrp_reply0;
          ethernet_proxy_arp_t *pa;
          fib_node_index_t dst_fei, src_fei;
          fib_prefix_t pfx0;
@@ -1097,10 +1099,19 @@ arp_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
          /* Fill in ethernet header. */
          eth0 = ethernet_buffer_get_header (p0);
 
+         is_vrrp_reply0 =
+           ((arp0->opcode ==
+             clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
+            &&
+            (!memcmp
+             (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
+              sizeof (vrrp_prefix))));
+
          /* Trash ARP packets whose ARP-level source addresses do not
-            match their L2-frame-level source addresses */
+            match their L2-frame-level source addresses, unless it's
+            a reply from a VRRP virtual router */
          if (memcmp (eth0->src_address, arp0->ip4_over_ethernet[0].ethernet,
-                     sizeof (eth0->src_address)))
+                     sizeof (eth0->src_address)) && !is_vrrp_reply0)
            {
              error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
              goto drop2;
@@ -2170,6 +2181,7 @@ arp_term_l2bd (vlib_main_t * vm,
          u16 bd_index0;
          u32 ip0;
          u8 *macp0;
+         u8 is_vrrp_reply0;
 
          pi0 = from[0];
          to_next[0] = pi0;
@@ -2218,12 +2230,20 @@ arp_term_l2bd (vlib_main_t * vm,
          if (error0)
            goto drop;
 
+         is_vrrp_reply0 =
+           ((arp0->opcode ==
+             clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply))
+            &&
+            (!memcmp
+             (arp0->ip4_over_ethernet[0].ethernet, vrrp_prefix,
+              sizeof (vrrp_prefix))));
+
          /* Trash ARP packets whose ARP-level source addresses do not
-            match their L2-frame-level source addresses  */
+            match their L2-frame-level source addresses, unless it's
+            a reply from a VRRP virtual router */
          if (PREDICT_FALSE
-             (memcmp
-              (eth0->src_address, arp0->ip4_over_ethernet[0].ethernet,
-               sizeof (eth0->src_address))))
+             (memcmp (eth0->src_address, arp0->ip4_over_ethernet[0].ethernet,
+                      sizeof (eth0->src_address)) && !is_vrrp_reply0))
            {
              error0 = ETHERNET_ARP_ERROR_l2_address_mismatch;
              goto drop;