NAT44: delete closed TCP session (VPP-1274)

Change-Id: Id25b447bddccb7b321123e4abc4134e7261a0807
Signed-off-by: Matus Fabian <matfabia@cisco.com>

4 files changed, 71 insertions, 25 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index d3369b6b49c..4a0d2653a81 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -535,7 +535,8 @@ nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip,
           if (ip->protocol == IP_PROTOCOL_TCP)
             {
               tcp_header_t *tcp = ip4_next_header(ip);
-              nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+              if (nat44_set_tcp_session_state (sm, s, tcp, thread_index))
+                return 1;
             }
           /* Per-user LRU list maintenance */
           clib_dlist_remove (tsm->list_pool, s->per_user_index);
@@ -1376,7 +1377,10 @@ snat_in2out_lb (snat_main_t *sm,
       if (is_fwd_bypass_session (s))
         {
           if (ip->protocol == IP_PROTOCOL_TCP)
-            nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+            {
+              if (nat44_set_tcp_session_state (sm, s, tcp, thread_index))
+                return 0;
+            }
           /* Per-user LRU list maintenance */
           clib_dlist_remove (tsm->list_pool, s->per_user_index);
           clib_dlist_addtail (tsm->list_pool, s->per_user_list_head_index,
@@ -1450,6 +1454,9 @@ snat_in2out_lb (snat_main_t *sm,
                           s->ext_host_addr.as_u32, ip4_header_t, dst_address);
   ip->checksum = ip_csum_fold (sum);
 
+  if (vnet_buffer(b)->sw_if_index[VLIB_TX] == ~0)
+    vnet_buffer(b)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
+
   if (PREDICT_TRUE(proto == SNAT_PROTOCOL_TCP))
     {
       old_port = tcp->src_port;
@@ -1470,7 +1477,8 @@ snat_in2out_lb (snat_main_t *sm,
           ip->dst_address.as_u32 = s->ext_host_addr.as_u32;
         }
       tcp->checksum = ip_csum_fold(sum);
-      nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+      if (nat44_set_tcp_session_state (sm, s, tcp, thread_index))
+        return s;
     }
   else
     {
@@ -1483,9 +1491,6 @@ snat_in2out_lb (snat_main_t *sm,
       udp->checksum = 0;
     }
 
-  if (vnet_buffer(b)->sw_if_index[VLIB_TX] == ~0)
-    vnet_buffer(b)->sw_if_index[VLIB_TX] = sm->outside_fib_index;
-
   /* Accounting */
   s->last_heard = now;
   s->total_pkts++;
@@ -1729,7 +1734,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp0->checksum = ip_csum_fold(sum0);
-              nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+              if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                goto trace00;
             }
           else
             {
@@ -1922,7 +1928,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp1->checksum = ip_csum_fold(sum1);
-              nat44_set_tcp_session_state (sm, s1, tcp1, thread_index);
+              if (nat44_set_tcp_session_state (sm, s1, tcp1, thread_index))
+                goto trace01;
             }
           else
             {
@@ -2152,7 +2159,8 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp0->checksum = ip_csum_fold(sum0);
-              nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+              if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                goto trace0;
             }
           else
             {
@@ -2669,6 +2677,10 @@ nat44_in2out_reass_node_fn (vlib_main_t * vm,
                                  src_address /* changed member */);
           ip0->checksum = ip_csum_fold (sum0);
 
+          /* Hairpinning */
+          nat44_reass_hairpinning (sm, b0, ip0, s0->out2in.port,
+                                   s0->ext_host_port, proto0);
+
           if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
             {
               if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
@@ -2685,7 +2697,8 @@ nat44_in2out_reass_node_fn (vlib_main_t * vm,
                                          ip4_header_t /* cheat */,
                                          length /* changed member */);
                   tcp0->checksum = ip_csum_fold(sum0);
-                  nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+                  if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                    goto trace0;
                 }
               else
                 {
@@ -2695,10 +2708,6 @@ nat44_in2out_reass_node_fn (vlib_main_t * vm,
                 }
             }
 
-          /* Hairpinning */
-          nat44_reass_hairpinning (sm, b0, ip0, s0->out2in.port,
-                                   s0->ext_host_port, proto0);
-
           /* Accounting */
           s0->last_heard = now;
           s0->total_pkts++;
diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index 61d26b2076c..78b7962b83e 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -687,6 +687,33 @@ user_session_increment(snat_main_t *sm, snat_user_t *u, u8 is_static)
 }
 
 always_inline void
+nat44_delete_session(snat_main_t * sm, snat_session_t * ses, u32 thread_index)
+{
+  snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
+                                                       thread_index);
+  clib_bihash_kv_8_8_t kv, value;
+  snat_user_key_t u_key;
+  snat_user_t *u;
+  u_key.addr = ses->in2out.addr;
+  u_key.fib_index = ses->in2out.fib_index;
+  kv.key = u_key.as_u64;
+  if (!clib_bihash_search_8_8 (&tsm->user_hash, &kv, &value))
+    {
+      u = pool_elt_at_index (tsm->users, value.value);
+      if (snat_is_session_static(ses))
+        u->nstaticsessions--;
+      else
+        u->nsessions--;
+    }
+  clib_dlist_remove (tsm->list_pool, ses->per_user_index);
+  pool_put_index (tsm->list_pool, ses->per_user_index);
+  pool_put (tsm->sessions, ses);
+}
+
+/** \brief Set TCP session stet.
+    @return 1 if session was closed, otherwise 0
+*/
+always_inline int
 nat44_set_tcp_session_state(snat_main_t * sm, snat_session_t * ses,
                             tcp_header_t * tcp, u32 thread_index)
 {
@@ -704,7 +731,11 @@ nat44_set_tcp_session_state(snat_main_t * sm, snat_session_t * ses,
     {
       nat_free_session_data (sm, ses, thread_index);
       ses->state = SNAT_SESSION_TCP_CLOSED;
+      nat44_delete_session (sm, ses, thread_index);
+      return 1;
     }
+
+  return 0;
 }
 
 #endif /* __included_snat_h__ */
diff --git a/src/plugins/nat/out2in.c b/src/plugins/nat/out2in.c
index c0f5a3c835a..6bc25b8cc22 100755
--- a/src/plugins/nat/out2in.c
+++ b/src/plugins/nat/out2in.c
@@ -410,7 +410,8 @@ create_bypass_for_fwd(snat_main_t * sm, ip4_header_t * ip, u32 rx_fib_index,
   if (ip->protocol == IP_PROTOCOL_TCP)
     {
       tcp_header_t *tcp = ip4_next_header(ip);
-      nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+      if (nat44_set_tcp_session_state (sm, s, tcp, thread_index))
+        return;
     }
   /* Per-user LRU list maintenance */
   clib_dlist_remove (tsm->list_pool, s->per_user_index);
@@ -1043,6 +1044,8 @@ snat_out2in_lb (snat_main_t *sm,
                           src_address);
   ip->checksum = ip_csum_fold (sum);
 
+  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
+
   if (PREDICT_TRUE(proto == SNAT_PROTOCOL_TCP))
     {
       old_port = tcp->dst_port;
@@ -1063,7 +1066,8 @@ snat_out2in_lb (snat_main_t *sm,
           ip->src_address.as_u32 = s->ext_host_nat_addr.as_u32;
         }
       tcp->checksum = ip_csum_fold(sum);
-      nat44_set_tcp_session_state (sm, s, tcp, thread_index);
+      if (nat44_set_tcp_session_state (sm, s, tcp, thread_index))
+        return s;
     }
   else
     {
@@ -1076,8 +1080,6 @@ snat_out2in_lb (snat_main_t *sm,
       udp->checksum = 0;
     }
 
-  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
-
   /* Accounting */
   s->last_heard = now;
   s->total_pkts++;
@@ -1306,7 +1308,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp0->checksum = ip_csum_fold(sum0);
-              nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+              if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                goto trace0;
             }
           else
             {
@@ -1485,7 +1488,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp1->checksum = ip_csum_fold(sum1);
-              nat44_set_tcp_session_state (sm, s1, tcp1, thread_index);
+              if (nat44_set_tcp_session_state (sm, s1, tcp1, thread_index))
+                goto trace1;
             }
           else
             {
@@ -1700,7 +1704,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
                                      ip4_header_t /* cheat */,
                                      length /* changed member */);
               tcp0->checksum = ip_csum_fold(sum0);
-              nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+              if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                goto trace00;
             }
           else
             {
@@ -1969,7 +1974,8 @@ nat44_out2in_reass_node_fn (vlib_main_t * vm,
                                          ip4_header_t /* cheat */,
                                          length /* changed member */);
                   tcp0->checksum = ip_csum_fold(sum0);
-                  nat44_set_tcp_session_state (sm, s0, tcp0, thread_index);
+                  if (nat44_set_tcp_session_state (sm, s0, tcp0, thread_index))
+                    goto trace0;
                 }
               else
                 {
diff --git a/test/test_nat.py b/test/test_nat.py
index 7c841f515c4..c2e36be7697 100644
--- a/test/test_nat.py
+++ b/test/test_nat.py
@@ -4208,7 +4208,7 @@ class TestNAT44(MethodHolder):
             self.initiate_tcp_session(self.pg0, self.pg1)
             sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
                                                          0)
-            self.assertEqual(len(sessions) - start_sessnum, 2)
+            self.assertEqual(len(sessions) - start_sessnum, 1)
         except:
             self.logger.error("TCP session termination failed")
             raise
@@ -4271,7 +4271,7 @@ class TestNAT44(MethodHolder):
             self.initiate_tcp_session(self.pg0, self.pg1)
             sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
                                                          0)
-            self.assertEqual(len(sessions) - start_sessnum, 2)
+            self.assertEqual(len(sessions) - start_sessnum, 1)
         except:
             self.logger.error("TCP session termination failed")
             raise
@@ -4333,7 +4333,7 @@ class TestNAT44(MethodHolder):
             self.initiate_tcp_session(self.pg0, self.pg1)
             sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4n,
                                                          0)
-            self.assertEqual(len(sessions) - start_sessnum, 2)
+            self.assertEqual(len(sessions) - start_sessnum, 1)
         except:
             self.logger.error("TCP session termination failed")
             raise