tcp: unlock link-local adjacencies on connection cleanup

Change-Id: I37705fb572045f42be4c2dabbd8460c8f8872167
Signed-off-by: Florin Coras <fcoras@cisco.com>

2 files changed, 56 insertions, 24 deletions

diff --git a/src/vnet/tcp/tcp.c b/src/vnet/tcp/tcp.c
index 6de48b2bd3a..b3564004dd4 100644
--- a/src/vnet/tcp/tcp.c
+++ b/src/vnet/tcp/tcp.c
@@ -28,6 +28,47 @@
 
 tcp_main_t tcp_main;
 
+typedef struct
+{
+  fib_protocol_t nh_proto;
+  vnet_link_t link_type;
+  ip46_address_t ip;
+  u32 sw_if_index;
+  u8 is_add;
+} tcp_add_del_adj_args_t;
+
+static void
+tcp_add_del_adj_cb (tcp_add_del_adj_args_t * args)
+{
+  u32 ai;
+  if (args->is_add)
+    {
+      adj_nbr_add_or_lock (args->nh_proto, args->link_type, &args->ip,
+			   args->sw_if_index);
+    }
+  else
+    {
+      ai = adj_nbr_find (FIB_PROTOCOL_IP6, VNET_LINK_IP6, &args->ip,
+			 args->sw_if_index);
+      if (ai != ADJ_INDEX_INVALID)
+	adj_unlock (ai);
+    }
+}
+
+static void
+tcp_add_del_adjacency (tcp_connection_t * tc, u8 is_add)
+{
+  tcp_add_del_adj_args_t args = {
+    .nh_proto = FIB_PROTOCOL_IP6,
+    .link_type = VNET_LINK_IP6,
+    .ip = tc->c_rmt_ip,
+    .sw_if_index = tc->sw_if_index,
+    .is_add = is_add
+  };
+  vlib_rpc_call_main_thread (tcp_add_del_adj_cb, (u8 *) & args,
+			     sizeof (args));
+}
+
 static u32
 tcp_connection_bind (u32 session_index, transport_endpoint_t * lcl)
 {
@@ -178,6 +219,9 @@ tcp_connection_cleanup (tcp_connection_t * tc)
       /* Make sure all timers are cleared */
       tcp_connection_timers_reset (tc);
 
+      if (!tc->c_is_ip4 && ip6_address_is_link_local_unicast (&tc->c_rmt_ip6))
+	tcp_add_del_adjacency (tc, 0);
+
       /* Poison the entry */
       if (CLIB_DEBUG > 0)
 	memset (tc, 0xFA, sizeof (*tc));
@@ -494,6 +538,9 @@ tcp_connection_init_vars (tcp_connection_t * tc)
   if (tc->state == TCP_STATE_SYN_RCVD)
     tcp_init_snd_vars (tc);
 
+  if (!tc->c_is_ip4 && ip6_address_is_link_local_unicast (&tc->c_rmt_ip6))
+    tcp_add_del_adjacency (tc, 1);
+
   //  tcp_connection_fib_attach (tc);
 }
 
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 0d938cae372..5932ed406d9 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -1755,21 +1755,6 @@ tcp_session_has_ooo_data (tcp_connection_t * tc)
   return svm_fifo_has_ooo_data (s->server_rx_fifo);
 }
 
-typedef struct
-{
-  fib_protocol_t nh_proto;
-  vnet_link_t link_type;
-  ip46_address_t ip;
-  u32 sw_if_index;
-} tcp_adj_add_args_t;
-
-void
-tcp_output_add_adj (tcp_adj_add_args_t * args)
-{
-  adj_nbr_add_or_lock (args->nh_proto, args->link_type, &args->ip,
-		       args->sw_if_index);
-}
-
 static void
 tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
 			      u32 * next0, u32 * error0)
@@ -1777,18 +1762,12 @@ tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
   ip_adjacency_t *adj;
   adj_index_t ai;
 
+  /* Not thread safe but as long as the connection exists the adj should
+   * not be removed */
   ai = adj_nbr_find (FIB_PROTOCOL_IP6, VNET_LINK_IP6, &tc0->c_rmt_ip,
 		     tc0->sw_if_index);
   if (ai == ADJ_INDEX_INVALID)
     {
-      tcp_adj_add_args_t args = {
-	.nh_proto = FIB_PROTOCOL_IP6,
-	.link_type = VNET_LINK_IP6,
-	.ip = tc0->c_rmt_ip,
-	.sw_if_index = tc0->sw_if_index
-      };
-      vlib_rpc_call_main_thread (tcp_output_add_adj, (u8 *) & args,
-				 sizeof (args));
       vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0;
       *next0 = TCP_OUTPUT_NEXT_DROP;
       *error0 = TCP_ERROR_LINK_LOCAL_RW;
@@ -1796,10 +1775,16 @@ tcp_output_handle_link_local (tcp_connection_t * tc0, vlib_buffer_t * b0,
     }
 
   adj = adj_get (ai);
-  if (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE)
+  if (PREDICT_TRUE (adj->lookup_next_index == IP_LOOKUP_NEXT_REWRITE))
     *next0 = TCP_OUTPUT_NEXT_IP_REWRITE;
   else if (adj->lookup_next_index == IP_LOOKUP_NEXT_ARP)
     *next0 = TCP_OUTPUT_NEXT_IP_ARP;
+  else
+    {
+      *next0 = TCP_OUTPUT_NEXT_DROP;
+      *error0 = TCP_ERROR_LINK_LOCAL_RW;
+    }
+  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = ai;
 }
 
 always_inline uword