api: clean up use of deprecated flag
[vpp.git] / src / plugins / nat / out2in_ed.c
index 3d081e1..8eef1e4 100644 (file)
@@ -190,6 +190,52 @@ nat44_o2i_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
 }
 #endif
 
+// allocate exact address based on preference
+static_always_inline int
+nat_alloc_addr_and_port_exact (snat_address_t * a,
+                              u32 thread_index,
+                              nat_protocol_t proto,
+                              ip4_address_t * addr,
+                              u16 * port,
+                              u16 port_per_thread, u32 snat_thread_index)
+{
+  u32 portnum;
+
+  switch (proto)
+    {
+#define _(N, j, n, s) \
+    case NAT_PROTOCOL_##N: \
+      if (a->busy_##n##_ports_per_thread[thread_index] < port_per_thread) \
+        { \
+          while (1) \
+            { \
+              portnum = (port_per_thread * \
+                snat_thread_index) + \
+                snat_random_port(0, port_per_thread - 1) + 1024; \
+              if (a->busy_##n##_port_refcounts[portnum]) \
+                continue; \
+             --a->busy_##n##_port_refcounts[portnum]; \
+              a->busy_##n##_ports_per_thread[thread_index]++; \
+              a->busy_##n##_ports++; \
+              *addr = a->addr; \
+              *port = clib_host_to_net_u16(portnum); \
+              return 0; \
+            } \
+        } \
+      break;
+      foreach_nat_protocol
+#undef _
+    default:
+      nat_elog_info ("unknown protocol");
+      return 1;
+    }
+
+  /* Totally out of translations to use... */
+  snat_ipfix_logging_addresses_exhausted (thread_index, 0);
+  return 1;
+}
+
+
 static snat_session_t *
 create_session_for_static_mapping_ed (snat_main_t * sm,
                                      vlib_buffer_t * b,
@@ -204,7 +250,8 @@ create_session_for_static_mapping_ed (snat_main_t * sm,
                                      u32 rx_fib_index,
                                      u32 thread_index,
                                      twice_nat_type_t twice_nat,
-                                     lb_nat_type_t lb_nat, f64 now)
+                                     lb_nat_type_t lb_nat, f64 now,
+                                     snat_static_mapping_t * mapping)
 {
   snat_session_t *s;
   ip4_header_t *ip;
@@ -261,13 +308,46 @@ create_session_for_static_mapping_ed (snat_main_t * sm,
   if (twice_nat == TWICE_NAT || (twice_nat == TWICE_NAT_SELF &&
                                 ip->src_address.as_u32 == i2o_addr.as_u32))
     {
-      if (snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
-                                              thread_index,
-                                              nat_proto,
-                                              &s->ext_host_nat_addr,
-                                              &s->ext_host_nat_port,
-                                              sm->port_per_thread,
-                                              tsm->snat_thread_index))
+      int rc = 0;
+      snat_address_t *filter = 0;
+
+      // if exact address is specified use this address
+      if (is_exact_address (mapping))
+       {
+         snat_address_t *ap;
+         vec_foreach (ap, sm->twice_nat_addresses)
+         {
+           if (mapping->pool_addr.as_u32 == ap->addr.as_u32)
+             {
+               filter = ap;
+               break;
+             }
+         }
+       }
+
+      if (filter)
+       {
+         rc = nat_alloc_addr_and_port_exact (filter,
+                                             thread_index,
+                                             nat_proto,
+                                             &s->ext_host_nat_addr,
+                                             &s->ext_host_nat_port,
+                                             sm->port_per_thread,
+                                             tsm->snat_thread_index);
+         s->flags |= SNAT_SESSION_FLAG_EXACT_ADDRESS;
+       }
+      else
+       {
+         rc =
+           snat_alloc_outside_address_and_port (sm->twice_nat_addresses, 0,
+                                                thread_index, nat_proto,
+                                                &s->ext_host_nat_addr,
+                                                &s->ext_host_nat_port,
+                                                sm->port_per_thread,
+                                                tsm->snat_thread_index);
+       }
+
+      if (rc)
        {
          b->error = node->errors[NAT_OUT2IN_ED_ERROR_OUT_OF_PORTS];
          nat_ed_session_delete (sm, s, thread_index, 1);
@@ -275,6 +355,7 @@ create_session_for_static_mapping_ed (snat_main_t * sm,
            nat_elog_notice ("out2in-ed key del failed");
          return 0;
        }
+
       s->flags |= SNAT_SESSION_FLAG_TWICE_NAT;
       init_ed_kv (&kv, i2o_addr, i2o_port, s->ext_host_nat_addr,
                  s->ext_host_nat_port, i2o_fib_index, ip->protocol,
@@ -310,6 +391,8 @@ create_session_for_static_mapping_ed (snat_main_t * sm,
               &s->ext_host_nat_addr, s->ext_host_nat_port,
               s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
 
+  per_vrf_sessions_register_session (s, thread_index);
+
   return s;
 }
 
@@ -407,6 +490,8 @@ create_bypass_for_fwd (snat_main_t * sm, vlib_buffer_t * b, ip4_header_t * ip,
       kv.value = s - tsm->sessions;
       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &kv, 1))
        nat_elog_notice ("in2out_ed key add failed");
+
+      per_vrf_sessions_register_session (s, thread_index);
     }
 
   if (ip->protocol == IP_PROTOCOL_TCP)
@@ -455,6 +540,7 @@ icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
   u16 sm_port;
   u32 sm_fib_index;
   *dont_translate = 0;
+  snat_static_mapping_t *m;
 
   sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
   rx_fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index);
@@ -469,12 +555,12 @@ icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
 
   if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv, &value))
     {
-      /* Try to match static mapping */
       if (snat_static_mapping_match
          (sm, ip->dst_address, l_port, rx_fib_index,
           ip_proto_to_nat_proto (ip->protocol), &sm_addr, &sm_port,
-          &sm_fib_index, 1, &is_addr_only, 0, 0, 0, &identity_nat))
+          &sm_fib_index, 1, &is_addr_only, 0, 0, 0, &identity_nat, &m))
        {
+         // static mapping not matched
          if (!sm->forwarding_enabled)
            {
              /* Don't NAT packet aimed at the intfc address */
@@ -482,11 +568,12 @@ icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
                                                    ip->dst_address.as_u32)))
                {
                  *dont_translate = 1;
-                 goto out;
                }
-             b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
-             next = NAT_NEXT_DROP;
-             goto out;
+             else
+               {
+                 b->error = node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
+                 next = NAT_NEXT_DROP;
+               }
            }
          else
            {
@@ -495,14 +582,17 @@ icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
                                thread_index, rx_fib_index))
                {
                  next = NAT_NEXT_IN2OUT_ED_FAST_PATH;
-                 goto out;
                }
-             if (sm->num_workers > 1)
-               create_bypass_for_fwd_worker (sm, b, ip, rx_fib_index);
              else
-               create_bypass_for_fwd (sm, b, ip, rx_fib_index, thread_index);
-             goto out;
+               {
+                 if (sm->num_workers > 1)
+                   create_bypass_for_fwd_worker (sm, b, ip, rx_fib_index);
+                 else
+                   create_bypass_for_fwd (sm, b, ip, rx_fib_index,
+                                          thread_index);
+               }
            }
+         goto out;
        }
 
       if (PREDICT_FALSE
@@ -529,13 +619,9 @@ icmp_match_out2in_ed (snat_main_t * sm, vlib_node_runtime_t * node,
                                              l_port, rx_fib_index, *proto,
                                              node, rx_fib_index,
                                              thread_index, 0, 0,
-                                             vlib_time_now (vm));
-
+                                             vlib_time_now (vm), m);
       if (!s)
-       {
-         next = NAT_NEXT_DROP;
-         goto out;
-       }
+       next = NAT_NEXT_DROP;
     }
   else
     {
@@ -651,6 +737,8 @@ nat44_ed_out2in_unknown_proto (snat_main_t * sm,
                  ip->protocol, thread_index, s - tsm->sessions);
       if (clib_bihash_add_del_16_8 (&tsm->in2out_ed, &s_kv, 1))
        nat_elog_notice ("in2out key add failed");
+
+      per_vrf_sessions_register_session (s, thread_index);
     }
 
   /* Update IP checksum */
@@ -675,218 +763,191 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
                                          vlib_frame_t * frame,
                                          int is_multi_worker)
 {
-  u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
-  nat_next_t next_index;
+  u32 n_left_from, *from;
   snat_main_t *sm = &snat_main;
   f64 now = vlib_time_now (vm);
   u32 thread_index = vm->thread_index;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
-    0, fragments = 0;
-
-  stats_node_index = sm->ed_out2in_node_index;
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
-  next_index = node->cached_next_index;
+
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
+  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
+  vlib_get_buffers (vm, from, b, n_left_from);
 
   while (n_left_from > 0)
     {
-      u32 n_left_to_next;
+      vlib_buffer_t *b0;
+      u32 sw_if_index0, rx_fib_index0, proto0, old_addr0, new_addr0;
+      u16 old_port0, new_port0;
+      ip4_header_t *ip0;
+      udp_header_t *udp0;
+      tcp_header_t *tcp0;
+      snat_session_t *s0 = 0;
+      clib_bihash_kv_16_8_t kv0, value0;
+      ip_csum_t sum0;
+
+      b0 = *b;
+      b++;
+
+      /* Prefetch next iteration. */
+      if (PREDICT_TRUE (n_left_from >= 2))
+       {
+         vlib_buffer_t *p2;
+
+         p2 = *b;
+
+         vlib_prefetch_buffer_header (p2, LOAD);
+
+         CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
+       }
+
+      next[0] = vnet_buffer2 (b0)->nat.arc_next;
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      vnet_buffer (b0)->snat.flags = 0;
+      ip0 = vlib_buffer_get_current (b0);
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      rx_fib_index0 =
+       fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4, sw_if_index0);
+
+      if (PREDICT_FALSE (ip0->ttl == 1))
        {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
-           new_addr0;
-         u16 old_port0, new_port0;
-         ip4_header_t *ip0;
-         udp_header_t *udp0;
-         tcp_header_t *tcp0;
-         snat_session_t *s0 = 0;
-         clib_bihash_kv_16_8_t kv0, value0;
-         ip_csum_t sum0;
-
-         /* speculatively enqueue b0 to the current next frame */
-         bi0 = from[0];
-         to_next[0] = bi0;
-         from += 1;
-         to_next += 1;
-         n_left_from -= 1;
-         n_left_to_next -= 1;
-
-         b0 = vlib_get_buffer (vm, bi0);
-         next0 = vnet_buffer2 (b0)->nat.arc_next;
-
-         vnet_buffer (b0)->snat.flags = 0;
-         ip0 = vlib_buffer_get_current (b0);
-
-         sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-         rx_fib_index0 =
-           fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
-                                                sw_if_index0);
-
-         if (PREDICT_FALSE (ip0->ttl == 1))
-           {
-             vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-             icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
-                                          ICMP4_time_exceeded_ttl_exceeded_in_transit,
-                                          0);
-             next0 = NAT_NEXT_ICMP_ERROR;
-             goto trace0;
-           }
+         vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+         icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+                                      ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                      0);
+         next[0] = NAT_NEXT_ICMP_ERROR;
+         goto trace0;
+       }
 
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
-           {
-             next0 = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
-             goto trace0;
-           }
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       {
+         next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
+         goto trace0;
+       }
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
-           {
-             next0 = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
-             goto trace0;
-           }
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
+         goto trace0;
+       }
 
-         init_ed_k (&kv0, ip0->dst_address,
-                    vnet_buffer (b0)->ip.reass.l4_dst_port, ip0->src_address,
-                    vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
-                    ip0->protocol);
-
-         /* there is a stashed index in vnet_buffer2 from handoff node,
-          * see if we can use it */
-         if (is_multi_worker && PREDICT_TRUE
-             (!pool_is_free_index
-              (tsm->sessions,
-               vnet_buffer2 (b0)->nat.ed_out2in_nat_session_index)))
+      init_ed_k (&kv0, ip0->dst_address,
+                vnet_buffer (b0)->ip.reass.l4_dst_port, ip0->src_address,
+                vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
+                ip0->protocol);
+
+      /* there is a stashed index in vnet_buffer2 from handoff node,
+       * see if we can use it */
+      if (is_multi_worker
+         &&
+         PREDICT_TRUE (!pool_is_free_index
+                       (tsm->sessions,
+                        vnet_buffer2 (b0)->nat.ed_out2in_nat_session_index)))
+       {
+         s0 = pool_elt_at_index (tsm->sessions,
+                                 vnet_buffer2 (b0)->
+                                 nat.ed_out2in_nat_session_index);
+         if (PREDICT_TRUE
+             (s0->out2in.addr.as_u32 == ip0->dst_address.as_u32
+              && s0->out2in.port == vnet_buffer (b0)->ip.reass.l4_dst_port
+              && s0->nat_proto == ip_proto_to_nat_proto (ip0->protocol)
+              && s0->out2in.fib_index == rx_fib_index0
+              && s0->ext_host_addr.as_u32 == ip0->src_address.as_u32
+              && s0->ext_host_port ==
+              vnet_buffer (b0)->ip.reass.l4_src_port))
            {
-             s0 = pool_elt_at_index (tsm->sessions,
-                                     vnet_buffer2 (b0)->
-                                     nat.ed_out2in_nat_session_index);
-             if (PREDICT_TRUE
-                 (s0->out2in.addr.as_u32 == ip0->dst_address.as_u32
-                  && s0->out2in.port ==
-                  vnet_buffer (b0)->ip.reass.l4_dst_port
-                  && s0->nat_proto == ip_proto_to_nat_proto (ip0->protocol)
-                  && s0->out2in.fib_index == rx_fib_index0
-                  && s0->ext_host_addr.as_u32 == ip0->src_address.as_u32
-                  && s0->ext_host_port ==
-                  vnet_buffer (b0)->ip.reass.l4_src_port))
-               {
-                 /* yes, this is the droid we're looking for */
-                 goto skip_lookup;
-               }
+             /* yes, this is the droid we're looking for */
+             goto skip_lookup;
            }
+       }
 
-         if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv0, &value0))
-           {
-             next0 = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
-             goto trace0;
-           }
-         ASSERT (thread_index == ed_value_get_thread_index (&value0));
-         s0 =
-           pool_elt_at_index (tsm->sessions,
-                              ed_value_get_session_index (&value0));
+      // lookup for session
+      if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv0, &value0))
+       {
+         // session does not exist go slow path
+         next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
+         goto trace0;
+       }
+      ASSERT (thread_index == ed_value_get_thread_index (&value0));
+      s0 =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&value0));
+
+    skip_lookup:
 
-       skip_lookup:
-         if (s0->tcp_closed_timestamp)
+      if (PREDICT_FALSE (per_vrf_sessions_is_expired (s0, thread_index)))
+       {
+         // session is closed, go slow path
+         nat_free_session_data (sm, s0, thread_index, 0);
+         nat_ed_session_delete (sm, s0, thread_index, 1);
+         next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
+         goto trace0;
+       }
+
+      if (s0->tcp_closed_timestamp)
+       {
+         if (now >= s0->tcp_closed_timestamp)
            {
-             if (now >= s0->tcp_closed_timestamp)
-               {
-                 // session is closed, go slow path
-                 next0 = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
-               }
-             else
-               {
-                 // session in transitory timeout, drop
-                 b0->error = node->errors[NAT_OUT2IN_ED_ERROR_TCP_CLOSED];
-                 next0 = NAT_NEXT_DROP;
-               }
-             goto trace0;
+             // session is closed, go slow path, freed in slow path
+             next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
            }
-
-         // drop if session expired
-         u64 sess_timeout_time;
-         sess_timeout_time = s0->last_heard +
-           (f64) nat44_session_get_timeout (sm, s0);
-         if (now >= sess_timeout_time)
+         else
            {
-             // session is closed, go slow path
-             nat_free_session_data (sm, s0, thread_index, 0);
-             nat_ed_session_delete (sm, s0, thread_index, 1);
-             next0 = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
-             goto trace0;
+             // session in transitory timeout, drop
+             b0->error = node->errors[NAT_OUT2IN_ED_ERROR_TCP_CLOSED];
+             next[0] = NAT_NEXT_DROP;
            }
-         //
+         goto trace0;
+       }
 
-         old_addr0 = ip0->dst_address.as_u32;
-         new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+      // drop if session expired
+      u64 sess_timeout_time;
+      sess_timeout_time =
+       s0->last_heard + (f64) nat44_session_get_timeout (sm, s0);
+      if (now >= sess_timeout_time)
+       {
+         // session is closed, go slow path
+         nat_free_session_data (sm, s0, thread_index, 0);
+         nat_ed_session_delete (sm, s0, thread_index, 1);
+         next[0] = NAT_NEXT_OUT2IN_ED_SLOW_PATH;
+         goto trace0;
+       }
 
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                dst_address);
-         if (PREDICT_FALSE (is_twice_nat_session (s0)))
-           sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
-                                  s0->ext_host_nat_addr.as_u32, ip4_header_t,
-                                  src_address);
-         ip0->checksum = ip_csum_fold (sum0);
+      old_addr0 = ip0->dst_address.as_u32;
+      new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 
-         old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                            dst_address);
+      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+       sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                              s0->ext_host_nat_addr.as_u32, ip4_header_t,
+                              src_address);
+      ip0->checksum = ip_csum_fold (sum0);
 
-         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
-           {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 sum0 = tcp0->checksum;
-                 sum0 =
-                   ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                   dst_address);
-                 sum0 =
-                   ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
-                                   length);
-                 if (is_twice_nat_session (s0))
-                   {
-                     sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
-                                            s0->ext_host_nat_addr.as_u32,
-                                            ip4_header_t, dst_address);
-                     sum0 =
-                       ip_csum_update (sum0,
-                                       vnet_buffer (b0)->ip.
-                                       reass.l4_src_port,
-                                       s0->ext_host_nat_port, ip4_header_t,
-                                       length);
-                     tcp0->src_port = s0->ext_host_nat_port;
-                     ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
-                   }
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
-             if (nat44_set_tcp_session_state_o2i
-                 (sm, now, s0,
-                  vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
-                  vnet_buffer (b0)->ip.reass.tcp_ack_number,
-                  vnet_buffer (b0)->ip.reass.tcp_seq_number, thread_index))
-               goto trace0;
-           }
-         else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
-                  && udp0->checksum)
+      old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
              new_port0 = udp0->dst_port = s0->in2out.port;
-             sum0 = udp0->checksum;
-             sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                    dst_address);
-             sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
-                                    length);
-             if (PREDICT_FALSE (is_twice_nat_session (s0)))
+             sum0 = tcp0->checksum;
+             sum0 =
+               ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                               dst_address);
+             sum0 =
+               ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
+                               length);
+             if (is_twice_nat_session (s0))
                {
                  sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
                                         s0->ext_host_nat_addr.as_u32,
@@ -896,74 +957,96 @@ nat44_ed_out2in_fast_path_node_fn_inline (vlib_main_t * vm,
                                    vnet_buffer (b0)->ip.reass.l4_src_port,
                                    s0->ext_host_nat_port, ip4_header_t,
                                    length);
-                 udp0->src_port = s0->ext_host_nat_port;
+                 tcp0->src_port = s0->ext_host_nat_port;
                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
                }
-             udp0->checksum = ip_csum_fold (sum0);
-             udp_packets++;
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.fastpath.out2in_ed.tcp,
+                                        thread_index, sw_if_index0, 1);
+         if (nat44_set_tcp_session_state_o2i
+             (sm, now, s0, vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
+              vnet_buffer (b0)->ip.reass.tcp_ack_number,
+              vnet_buffer (b0)->ip.reass.tcp_seq_number, thread_index))
+           goto trace0;
+       }
+      else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
+              && udp0->checksum)
+       {
+         new_port0 = udp0->dst_port = s0->in2out.port;
+         sum0 = udp0->checksum;
+         sum0 =
+           ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                           dst_address);
+         sum0 =
+           ip_csum_update (sum0, old_port0, new_port0, ip4_header_t, length);
+         if (PREDICT_FALSE (is_twice_nat_session (s0)))
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+             sum0 =
+               ip_csum_update (sum0, ip0->src_address.as_u32,
+                               s0->ext_host_nat_addr.as_u32, ip4_header_t,
+                               dst_address);
+             sum0 =
+               ip_csum_update (sum0, vnet_buffer (b0)->ip.reass.l4_src_port,
+                               s0->ext_host_nat_port, ip4_header_t, length);
+             udp0->src_port = s0->ext_host_nat_port;
+             ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+           }
+         udp0->checksum = ip_csum_fold (sum0);
+         vlib_increment_simple_counter (&sm->counters.fastpath.out2in_ed.udp,
+                                        thread_index, sw_if_index0, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+           {
+             new_port0 = udp0->dst_port = s0->in2out.port;
+             if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 if (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     udp0->src_port = s0->ext_host_nat_port;
-                     ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
-                   }
+                 udp0->src_port = s0->ext_host_nat_port;
+                 ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
                }
-             udp_packets++;
            }
+         vlib_increment_simple_counter (&sm->counters.fastpath.out2in_ed.udp,
+                                        thread_index, sw_if_index0, 1);
+       }
 
-         /* Accounting */
-         nat44_session_update_counters (s0, now,
-                                        vlib_buffer_length_in_chain (vm, b0),
-                                        thread_index);
-         /* Per-user LRU list maintenance */
-         nat44_session_update_lru (sm, s0, thread_index);
+      /* Accounting */
+      nat44_session_update_counters (s0, now,
+                                    vlib_buffer_length_in_chain (vm, b0),
+                                    thread_index);
+      /* Per-user LRU list maintenance */
+      nat44_session_update_lru (sm, s0, thread_index);
 
-       trace0:
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             nat44_ed_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
-             t->is_slow_path = 0;
-
-             if (s0)
-               t->session_index = s0 - tsm->sessions;
-             else
-               t->session_index = ~0;
-           }
+    trace0:
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         nat44_ed_out2in_trace_t *t =
+           vlib_add_trace (vm, node, b0, sizeof (*t));
+         t->sw_if_index = sw_if_index0;
+         t->next_index = next[0];
+         t->is_slow_path = 0;
+
+         if (s0)
+           t->session_index = s0 - tsm->sessions;
+         else
+           t->session_index = ~0;
+       }
 
-         pkts_processed += next0 == vnet_buffer2 (b0)->nat.arc_next;
-         /* verify speculative enqueue, maybe switch current next frame */
-         vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
-                                          to_next, n_left_to_next,
-                                          bi0, next0);
+      if (next[0] == NAT_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.fastpath.
+                                        out2in_ed.drops, thread_index,
+                                        sw_if_index0, 1);
        }
 
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+      n_left_from--;
+      next++;
     }
 
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_TCP_PACKETS, tcp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_UDP_PACKETS, udp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_ICMP_PACKETS,
-                              icmp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_OTHER_PACKETS,
-                              other_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_FRAGMENTS, fragments);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
   return frame->n_vectors;
 }
 
@@ -972,166 +1055,152 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
                                          vlib_node_runtime_t * node,
                                          vlib_frame_t * frame)
 {
-  u32 n_left_from, *from, *to_next, pkts_processed = 0, stats_node_index;
-  nat_next_t next_index;
+  u32 n_left_from, *from;
   snat_main_t *sm = &snat_main;
   f64 now = vlib_time_now (vm);
   u32 thread_index = vm->thread_index;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
-    0, fragments = 0;
-
-  stats_node_index = sm->ed_out2in_slowpath_node_index;
+  snat_static_mapping_t *m;
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
-  next_index = node->cached_next_index;
+
+  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
+  u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
+  vlib_get_buffers (vm, from, b, n_left_from);
 
   while (n_left_from > 0)
     {
-      u32 n_left_to_next;
+      vlib_buffer_t *b0;
+      u32 sw_if_index0, rx_fib_index0, proto0, old_addr0, new_addr0;
+      u16 old_port0, new_port0;
+      ip4_header_t *ip0;
+      udp_header_t *udp0;
+      tcp_header_t *tcp0;
+      icmp46_header_t *icmp0;
+      snat_session_t *s0 = 0;
+      clib_bihash_kv_16_8_t kv0, value0;
+      ip_csum_t sum0;
+      lb_nat_type_t lb_nat0;
+      twice_nat_type_t twice_nat0;
+      u8 identity_nat0;
+      ip4_address_t sm_addr;
+      u16 sm_port;
+      u32 sm_fib_index;
+
+      b0 = *b;
+      next[0] = vnet_buffer2 (b0)->nat.arc_next;
+
+      vnet_buffer (b0)->snat.flags = 0;
+      ip0 = vlib_buffer_get_current (b0);
+
+      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      rx_fib_index0 =
+       fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4, sw_if_index0);
+
+      if (PREDICT_FALSE (ip0->ttl == 1))
+       {
+         vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+         icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
+                                      ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                      0);
+         next[0] = NAT_NEXT_ICMP_ERROR;
+         goto trace0;
+       }
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      icmp0 = (icmp46_header_t *) udp0;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
        {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0, sw_if_index0, rx_fib_index0, proto0, old_addr0,
-           new_addr0;
-         u16 old_port0, new_port0;
-         ip4_header_t *ip0;
-         udp_header_t *udp0;
-         tcp_header_t *tcp0;
-         icmp46_header_t *icmp0;
-         snat_session_t *s0 = 0;
-         clib_bihash_kv_16_8_t kv0, value0;
-         ip_csum_t sum0;
-         lb_nat_type_t lb_nat0;
-         twice_nat_type_t twice_nat0;
-         u8 identity_nat0;
-         ip4_address_t sm_addr;
-         u16 sm_port;
-         u32 sm_fib_index;
-
-         /* speculatively enqueue b0 to the current next frame */
-         bi0 = from[0];
-         to_next[0] = bi0;
-         from += 1;
-         to_next += 1;
-         n_left_from -= 1;
-         n_left_to_next -= 1;
-
-         b0 = vlib_get_buffer (vm, bi0);
-         next0 = vnet_buffer2 (b0)->nat.arc_next;
-
-         vnet_buffer (b0)->snat.flags = 0;
-         ip0 = vlib_buffer_get_current (b0);
-
-         sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-         rx_fib_index0 =
-           fib_table_get_index_for_sw_if_index (FIB_PROTOCOL_IP4,
-                                                sw_if_index0);
-
-         if (PREDICT_FALSE (ip0->ttl == 1))
+         s0 =
+           nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
+                                          thread_index, now, vm, node);
+         if (!sm->forwarding_enabled)
            {
-             vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-             icmp4_error_set_vnet_buffer (b0, ICMP4_time_exceeded,
-                                          ICMP4_time_exceeded_ttl_exceeded_in_transit,
-                                          0);
-             next0 = NAT_NEXT_ICMP_ERROR;
-             goto trace0;
+             if (!s0)
+               next[0] = NAT_NEXT_DROP;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.
+                                        out2in_ed.other, thread_index,
+                                        sw_if_index0, 1);
+         goto trace0;
+       }
 
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-         proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next[0] = icmp_out2in_ed_slow_path
+           (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+            next[0], now, thread_index, &s0);
+         vlib_increment_simple_counter (&sm->counters.slowpath.
+                                        out2in_ed.icmp, thread_index,
+                                        sw_if_index0, 1);
+         goto trace0;
+       }
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
-           {
-             s0 =
-               nat44_ed_out2in_unknown_proto (sm, b0, ip0, rx_fib_index0,
-                                              thread_index, now, vm, node);
-             if (!sm->forwarding_enabled)
-               {
-                 if (!s0)
-                   next0 = NAT_NEXT_DROP;
-               }
-             other_packets++;
-             goto trace0;
-           }
+      init_ed_k (&kv0, ip0->dst_address,
+                vnet_buffer (b0)->ip.reass.l4_dst_port, ip0->src_address,
+                vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
+                ip0->protocol);
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+      s0 = NULL;
+      if (!clib_bihash_search_16_8 (&sm->out2in_ed, &kv0, &value0))
+       {
+         ASSERT (thread_index == ed_value_get_thread_index (&value0));
+         s0 =
+           pool_elt_at_index (tsm->sessions,
+                              ed_value_get_session_index (&value0));
+
+         if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
            {
-             next0 = icmp_out2in_ed_slow_path
-               (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                next0, now, thread_index, &s0);
-             icmp_packets++;
-             goto trace0;
+             nat_free_session_data (sm, s0, thread_index, 0);
+             nat_ed_session_delete (sm, s0, thread_index, 1);
+             s0 = NULL;
            }
+       }
 
-         init_ed_k (&kv0, ip0->dst_address,
-                    vnet_buffer (b0)->ip.reass.l4_dst_port, ip0->src_address,
-                    vnet_buffer (b0)->ip.reass.l4_src_port, rx_fib_index0,
-                    ip0->protocol);
-
-         s0 = NULL;
-         if (!clib_bihash_search_16_8 (&sm->out2in_ed, &kv0, &value0))
+      if (!s0)
+       {
+         /* Try to match static mapping by external address and port,
+            destination address and port in packet */
+
+         if (snat_static_mapping_match
+             (sm, ip0->dst_address,
+              vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+              proto0, &sm_addr, &sm_port, &sm_fib_index, 1, 0,
+              &twice_nat0, &lb_nat0, &ip0->src_address, &identity_nat0, &m))
            {
-             ASSERT (thread_index == ed_value_get_thread_index (&value0));
-             s0 =
-               pool_elt_at_index (tsm->sessions,
-                                  ed_value_get_session_index (&value0));
-
-             if (s0->tcp_closed_timestamp && now >= s0->tcp_closed_timestamp)
+             /*
+              * Send DHCP packets to the ipv4 stack, or we won't
+              * be able to use dhcp client on the outside interface
+              */
+             if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_UDP
+                                && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
+                                    clib_host_to_net_u16
+                                    (UDP_DST_PORT_dhcp_to_client))))
                {
-                 nat_free_session_data (sm, s0, thread_index, 0);
-                 nat_ed_session_delete (sm, s0, thread_index, 1);
-                 s0 = NULL;
+                 goto trace0;
                }
-           }
 
-         if (!s0)
-           {
-             /* Try to match static mapping by external address and port,
-                destination address and port in packet */
-
-             if (snat_static_mapping_match
-                 (sm, ip0->dst_address,
-                  vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
-                  proto0, &sm_addr, &sm_port, &sm_fib_index, 1, 0,
-                  &twice_nat0, &lb_nat0, &ip0->src_address, &identity_nat0))
+             if (!sm->forwarding_enabled)
                {
-                 /*
-                  * Send DHCP packets to the ipv4 stack, or we won't
-                  * be able to use dhcp client on the outside interface
-                  */
-                 if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_UDP
-                                    && (vnet_buffer (b0)->ip.
-                                        reass.l4_dst_port ==
-                                        clib_host_to_net_u16
-                                        (UDP_DST_PORT_dhcp_to_client))))
-                   {
-                     goto trace0;
-                   }
-
-                 if (!sm->forwarding_enabled)
+                 b0->error =
+                   node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
+                 next[0] = NAT_NEXT_DROP;
+               }
+             else
+               {
+                 if (next_src_nat
+                     (sm, ip0, vnet_buffer (b0)->ip.reass.l4_src_port,
+                      vnet_buffer (b0)->ip.reass.l4_dst_port,
+                      thread_index, rx_fib_index0))
                    {
-                     b0->error =
-                       node->errors[NAT_OUT2IN_ED_ERROR_NO_TRANSLATION];
-                     next0 = NAT_NEXT_DROP;
+                     next[0] = NAT_NEXT_IN2OUT_ED_FAST_PATH;
                    }
                  else
                    {
-                     if (next_src_nat
-                         (sm, ip0, vnet_buffer (b0)->ip.reass.l4_src_port,
-                          vnet_buffer (b0)->ip.reass.l4_dst_port,
-                          thread_index, rx_fib_index0))
-                       {
-                         next0 = NAT_NEXT_IN2OUT_ED_FAST_PATH;
-                         goto trace0;
-                       }
                      if (sm->num_workers > 1)
                        create_bypass_for_fwd_worker (sm, b0, ip0,
                                                      rx_fib_index0);
@@ -1139,102 +1208,68 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
                        create_bypass_for_fwd (sm, b0, ip0, rx_fib_index0,
                                               thread_index);
                    }
-                 goto trace0;
                }
+             goto trace0;
+           }
 
-             if (PREDICT_FALSE (identity_nat0))
-               goto trace0;
+         if (PREDICT_FALSE (identity_nat0))
+           goto trace0;
 
-             if ((proto0 == NAT_PROTOCOL_TCP)
-                 && !tcp_flags_is_init (vnet_buffer (b0)->ip.
-                                        reass.icmp_type_or_tcp_flags))
-               {
-                 b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
-                 next0 = NAT_NEXT_DROP;
-                 goto trace0;
-               }
+         if ((proto0 == NAT_PROTOCOL_TCP)
+             && !tcp_flags_is_init (vnet_buffer (b0)->ip.
+                                    reass.icmp_type_or_tcp_flags))
+           {
+             b0->error = node->errors[NAT_OUT2IN_ED_ERROR_NON_SYN];
+             next[0] = NAT_NEXT_DROP;
+             goto trace0;
+           }
 
-             /* Create session initiated by host from external network */
-             s0 = create_session_for_static_mapping_ed (sm, b0,
-                                                        sm_addr, sm_port,
-                                                        sm_fib_index,
-                                                        ip0->dst_address,
-                                                        vnet_buffer (b0)->
-                                                        ip.reass.l4_dst_port,
-                                                        rx_fib_index0,
-                                                        proto0, node,
-                                                        rx_fib_index0,
-                                                        thread_index,
-                                                        twice_nat0, lb_nat0,
-                                                        now);
-             if (!s0)
-               {
-                 next0 = NAT_NEXT_DROP;
-                 goto trace0;
-               }
+         /* Create session initiated by host from external network */
+         s0 = create_session_for_static_mapping_ed (sm, b0,
+                                                    sm_addr, sm_port,
+                                                    sm_fib_index,
+                                                    ip0->dst_address,
+                                                    vnet_buffer (b0)->
+                                                    ip.reass.l4_dst_port,
+                                                    rx_fib_index0, proto0,
+                                                    node, rx_fib_index0,
+                                                    thread_index, twice_nat0,
+                                                    lb_nat0, now, m);
+         if (!s0)
+           {
+             next[0] = NAT_NEXT_DROP;
+             goto trace0;
            }
+       }
 
-         old_addr0 = ip0->dst_address.as_u32;
-         new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+      old_addr0 = ip0->dst_address.as_u32;
+      new_addr0 = ip0->dst_address.as_u32 = s0->in2out.addr.as_u32;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                dst_address);
-         if (PREDICT_FALSE (is_twice_nat_session (s0)))
-           sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
-                                  s0->ext_host_nat_addr.as_u32, ip4_header_t,
-                                  src_address);
-         ip0->checksum = ip_csum_fold (sum0);
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                            dst_address);
+      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+       sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                              s0->ext_host_nat_addr.as_u32, ip4_header_t,
+                              src_address);
+      ip0->checksum = ip_csum_fold (sum0);
 
-         old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+      old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
 
-         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
-           {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 sum0 = tcp0->checksum;
-                 sum0 =
-                   ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                   dst_address);
-                 sum0 =
-                   ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
-                                   length);
-                 if (is_twice_nat_session (s0))
-                   {
-                     sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
-                                            s0->ext_host_nat_addr.as_u32,
-                                            ip4_header_t, dst_address);
-                     sum0 =
-                       ip_csum_update (sum0,
-                                       vnet_buffer (b0)->ip.
-                                       reass.l4_src_port,
-                                       s0->ext_host_nat_port, ip4_header_t,
-                                       length);
-                     tcp0->src_port = s0->ext_host_nat_port;
-                     ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
-                   }
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
-             if (nat44_set_tcp_session_state_o2i
-                 (sm, now, s0,
-                  vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
-                  vnet_buffer (b0)->ip.reass.tcp_ack_number,
-                  vnet_buffer (b0)->ip.reass.tcp_seq_number, thread_index))
-               goto trace0;
-           }
-         else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
-                  && udp0->checksum)
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
              new_port0 = udp0->dst_port = s0->in2out.port;
-             sum0 = udp0->checksum;
-             sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                    dst_address);
-             sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
-                                    length);
-             if (PREDICT_FALSE (is_twice_nat_session (s0)))
+             sum0 = tcp0->checksum;
+             sum0 =
+               ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                               dst_address);
+             sum0 =
+               ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
+                               length);
+             if (is_twice_nat_session (s0))
                {
                  sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
                                         s0->ext_host_nat_addr.as_u32,
@@ -1244,74 +1279,97 @@ nat44_ed_out2in_slow_path_node_fn_inline (vlib_main_t * vm,
                                    vnet_buffer (b0)->ip.reass.l4_src_port,
                                    s0->ext_host_nat_port, ip4_header_t,
                                    length);
-                 udp0->src_port = s0->ext_host_nat_port;
+                 tcp0->src_port = s0->ext_host_nat_port;
                  ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
                }
-             udp0->checksum = ip_csum_fold (sum0);
-             udp_packets++;
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in_ed.tcp,
+                                        thread_index, sw_if_index0, 1);
+         if (nat44_set_tcp_session_state_o2i
+             (sm, now, s0, vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags,
+              vnet_buffer (b0)->ip.reass.tcp_ack_number,
+              vnet_buffer (b0)->ip.reass.tcp_seq_number, thread_index))
+           goto trace0;
+       }
+      else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
+              && udp0->checksum)
+       {
+         new_port0 = udp0->dst_port = s0->in2out.port;
+         sum0 = udp0->checksum;
+         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                dst_address);
+         sum0 = ip_csum_update (sum0, old_port0, new_port0, ip4_header_t,
+                                length);
+         if (PREDICT_FALSE (is_twice_nat_session (s0)))
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+             sum0 = ip_csum_update (sum0, ip0->src_address.as_u32,
+                                    s0->ext_host_nat_addr.as_u32,
+                                    ip4_header_t, dst_address);
+             sum0 =
+               ip_csum_update (sum0,
+                               vnet_buffer (b0)->ip.reass.l4_src_port,
+                               s0->ext_host_nat_port, ip4_header_t, length);
+             udp0->src_port = s0->ext_host_nat_port;
+             ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
+           }
+         udp0->checksum = ip_csum_fold (sum0);
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in_ed.udp,
+                                        thread_index, sw_if_index0, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+           {
+             new_port0 = udp0->dst_port = s0->in2out.port;
+             if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 if (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     udp0->src_port = s0->ext_host_nat_port;
-                     ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
-                   }
+                 udp0->src_port = s0->ext_host_nat_port;
+                 ip0->src_address.as_u32 = s0->ext_host_nat_addr.as_u32;
                }
-             udp_packets++;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in_ed.udp,
+                                        thread_index, sw_if_index0, 1);
+       }
 
-         /* Accounting */
-         nat44_session_update_counters (s0, now,
-                                        vlib_buffer_length_in_chain (vm, b0),
-                                        thread_index);
-         /* Per-user LRU list maintenance */
-         nat44_session_update_lru (sm, s0, thread_index);
+      /* Accounting */
+      nat44_session_update_counters (s0, now,
+                                    vlib_buffer_length_in_chain (vm, b0),
+                                    thread_index);
+      /* Per-user LRU list maintenance */
+      nat44_session_update_lru (sm, s0, thread_index);
 
-       trace0:
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             nat44_ed_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
-             t->is_slow_path = 1;
-
-             if (s0)
-               t->session_index = s0 - tsm->sessions;
-             else
-               t->session_index = ~0;
-           }
+    trace0:
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         nat44_ed_out2in_trace_t *t =
+           vlib_add_trace (vm, node, b0, sizeof (*t));
+         t->sw_if_index = sw_if_index0;
+         t->next_index = next[0];
+         t->is_slow_path = 1;
+
+         if (s0)
+           t->session_index = s0 - tsm->sessions;
+         else
+           t->session_index = ~0;
+       }
 
-         pkts_processed += next0 == vnet_buffer2 (b0)->nat.arc_next;
-         /* verify speculative enqueue, maybe switch current next frame */
-         vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
-                                          to_next, n_left_to_next,
-                                          bi0, next0);
+      if (next[0] == NAT_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.slowpath.
+                                        out2in_ed.drops, thread_index,
+                                        sw_if_index0, 1);
        }
 
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+      n_left_from--;
+      next++;
+      b++;
     }
 
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_OUT2IN_PACKETS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_TCP_PACKETS, tcp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_UDP_PACKETS, udp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_ICMP_PACKETS,
-                              icmp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_OTHER_PACKETS,
-                              other_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_OUT2IN_ED_ERROR_FRAGMENTS, fragments);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
+
   return frame->n_vectors;
 }