Use unicast DMAC for IP neighbor pool refresh probes

Change-Id: I12fbebd1d24c37dc77c147773ea522c8a4b7b99d
Signed-off-by: John Lo <loj@cisco.com>

7 files changed, 28 insertions, 15 deletions

diff --git a/src/vnet/ip/ip4.h b/src/vnet/ip/ip4.h
index 524a90d2616..8187a9dd0e2 100644
--- a/src/vnet/ip/ip4.h
+++ b/src/vnet/ip/ip4.h
@@ -251,7 +251,7 @@ int ip4_address_compare (ip4_address_t * a1, ip4_address_t * a2);
 
 /* Send an ARP request to see if given destination is reachable on given interface. */
 clib_error_t *ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst,
-				  u32 sw_if_index);
+				  u32 sw_if_index, u8 refresh);
 
 clib_error_t *ip4_set_arp_limit (u32 arp_limit);
 
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 3444eb88b7c..0035cc8a552 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -1918,7 +1918,8 @@ VLIB_INIT_FUNCTION (arp_notrace_init);
 
 /* Send an ARP request to see if given destination is reachable on given interface. */
 clib_error_t *
-ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
+ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index,
+		    u8 refresh)
 {
   vnet_main_t *vnm = vnet_get_main ();
   ip4_main_t *im = &ip4_main;
@@ -1931,6 +1932,7 @@ ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
   vlib_buffer_t *b;
   adj_index_t ai;
   u32 bi = 0;
+  u8 unicast_rewrite = 0;
 
   si = vnet_get_sw_interface (vnm, sw_if_index);
 
@@ -1988,14 +1990,24 @@ ip4_probe_neighbor (vlib_main_t * vm, ip4_address_t * dst, u32 sw_if_index)
   /* Peer has been previously resolved, retrieve glean adj instead */
   if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE)
     {
-      adj_unlock (ai);
-      ai = adj_glean_add_or_lock (FIB_PROTOCOL_IP4,
-				  VNET_LINK_IP4, sw_if_index, &nh);
-      adj = adj_get (ai);
+      if (refresh)
+	unicast_rewrite = 1;
+      else
+	{
+	  adj_unlock (ai);
+	  ai = adj_glean_add_or_lock (FIB_PROTOCOL_IP4,
+				      VNET_LINK_IP4, sw_if_index, &nh);
+	  adj = adj_get (ai);
+	}
     }
 
   /* Add encapsulation string for software interface (e.g. ethernet header). */
   vnet_rewrite_one_header (adj[0], h, sizeof (ethernet_header_t));
+  if (unicast_rewrite)
+    {
+      u16 *etype = vlib_buffer_get_current (b) - 2;
+      etype[0] = clib_host_to_net_u16 (ETHERNET_TYPE_ARP);
+    }
   vlib_buffer_advance (b, -adj->rewrite_header.data_bytes);
 
   {
diff --git a/src/vnet/ip/ip6.h b/src/vnet/ip/ip6.h
index 6f6724b3903..8b1516cf353 100644
--- a/src/vnet/ip/ip6.h
+++ b/src/vnet/ip/ip6.h
@@ -354,7 +354,7 @@ ip6_address_t *ip6_interface_first_address (ip6_main_t * im, u32 sw_if_index);
 int ip6_address_compare (ip6_address_t * a1, ip6_address_t * a2);
 
 clib_error_t *ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst,
-				  u32 sw_if_index);
+				  u32 sw_if_index, u8 refresh);
 
 uword
 ip6_udp_register_listener (vlib_main_t * vm,
diff --git a/src/vnet/ip/ip6_forward.c b/src/vnet/ip/ip6_forward.c
index f7946b0b3af..5ea7d8d6e9d 100644
--- a/src/vnet/ip/ip6_forward.c
+++ b/src/vnet/ip/ip6_forward.c
@@ -1435,7 +1435,8 @@ ip6_register_protocol (u32 protocol, u32 node_index)
 }
 
 clib_error_t *
-ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst, u32 sw_if_index)
+ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst, u32 sw_if_index,
+		    u8 refresh)
 {
   vnet_main_t *vnm = vnet_get_main ();
   ip6_main_t *im = &ip6_main;
@@ -1516,7 +1517,7 @@ ip6_probe_neighbor (vlib_main_t * vm, ip6_address_t * dst, u32 sw_if_index)
   adj = adj_get (ai);
 
   /* Peer has been previously resolved, retrieve glean adj instead */
-  if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE)
+  if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE && refresh == 0)
     {
       adj_unlock (ai);
       ai = adj_glean_add_or_lock (FIB_PROTOCOL_IP6,
diff --git a/src/vnet/ip/ip_api.c b/src/vnet/ip/ip_api.c
index 48e523f381a..92393cb5079 100644
--- a/src/vnet/ip/ip_api.c
+++ b/src/vnet/ip/ip_api.c
@@ -2993,10 +2993,10 @@ vl_api_ip_probe_neighbor_t_handler (vl_api_ip_probe_neighbor_t * mp)
 
   if (mp->is_ipv6)
     error = ip6_probe_neighbor (vm, (ip6_address_t *) mp->dst_address,
-				sw_if_index);
+				sw_if_index, 0);
   else
     error = ip4_probe_neighbor (vm, (ip4_address_t *) mp->dst_address,
-				sw_if_index);
+				sw_if_index, 0);
 
   if (error)
     {
diff --git a/src/vnet/ip/ip_neighbor.c b/src/vnet/ip/ip_neighbor.c
index c97fb2b3cd4..80437655f92 100644
--- a/src/vnet/ip/ip_neighbor.c
+++ b/src/vnet/ip/ip_neighbor.c
@@ -143,10 +143,10 @@ ip_neighbor_scan (vlib_main_t * vm, f64 start_time, u32 start_idx,
 	  update_count[0]++;
 	  /* probe neighbor */
 	  if (!is_ip6)
-	    ip4_probe_neighbor (vm, &n4->ip4_address, n4->sw_if_index);
+	    ip4_probe_neighbor (vm, &n4->ip4_address, n4->sw_if_index, 1);
 	  else
 	    ip6_probe_neighbor (vm, &n6->key.ip6_address,
-				n6->key.sw_if_index);
+				n6->key.sw_if_index, 1);
 	}
 
     next_neighbor:
diff --git a/src/vnet/ip/lookup.c b/src/vnet/ip/lookup.c
index 0b376812250..e0d1ac06dfb 100644
--- a/src/vnet/ip/lookup.c
+++ b/src/vnet/ip/lookup.c
@@ -1101,7 +1101,7 @@ ip6_probe_neighbor_wait (vlib_main_t * vm, ip6_address_t * a, u32 sw_if_index,
   for (i = 0; i < retry_count; i++)
     {
       /* The interface may be down, etc. */
-      e = ip6_probe_neighbor (vm, a, sw_if_index);
+      e = ip6_probe_neighbor (vm, a, sw_if_index, 0);
 
       if (e)
 	return e;
@@ -1153,7 +1153,7 @@ ip4_probe_neighbor_wait (vlib_main_t * vm, ip4_address_t * a, u32 sw_if_index,
   for (i = 0; i < retry_count; i++)
     {
       /* The interface may be down, etc. */
-      e = ip4_probe_neighbor (vm, a, sw_if_index);
+      e = ip4_probe_neighbor (vm, a, sw_if_index, 0);
 
       if (e)
 	return e;