nat: cleanup & reorganization
[vpp.git] / src / plugins / nat / out2in.c
index 57e658b..c8c4542 100644 (file)
 
 #include <vlib/vlib.h>
 #include <vnet/vnet.h>
-#include <vnet/pg/pg.h>
 
 #include <vnet/ip/ip.h>
-#include <vnet/udp/udp.h>
+#include <vnet/udp/udp_local.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/fib/ip4_fib.h>
 #include <nat/nat.h>
-#include <nat/nat_ipfix_logging.h>
+#include <nat/lib/ipfix_logging.h>
 #include <nat/nat_inlines.h>
 #include <nat/nat44/inlines.h>
-#include <nat/nat_syslog.h>
+#include <nat/lib/nat_syslog.h>
 #include <nat/nat_ha.h>
 
 #include <vppinfra/hash.h>
@@ -72,21 +71,11 @@ format_snat_out2in_fast_trace (u8 * s, va_list * args)
 
 #define foreach_snat_out2in_error                       \
 _(UNSUPPORTED_PROTOCOL, "unsupported protocol")         \
-_(OUT2IN_PACKETS, "good out2in packets processed")      \
 _(OUT_OF_PORTS, "out of ports")                         \
 _(BAD_ICMP_TYPE, "unsupported ICMP type")               \
 _(NO_TRANSLATION, "no translation")                     \
 _(MAX_SESSIONS_EXCEEDED, "maximum sessions exceeded")   \
-_(DROP_FRAGMENT, "drop fragment")                       \
-_(MAX_REASS, "maximum reassemblies exceeded")           \
-_(MAX_FRAG, "maximum fragments per reassembly exceeded")\
-_(TCP_PACKETS, "TCP packets")                           \
-_(UDP_PACKETS, "UDP packets")                           \
-_(ICMP_PACKETS, "ICMP packets")                         \
-_(OTHER_PACKETS, "other protocol packets")              \
-_(FRAGMENTS, "fragments")                               \
-_(CACHED_FRAGMENTS, "cached fragments")                 \
-_(PROCESSED_FRAGMENTS, "processed fragments")
+_(CANNOT_CREATE_USER, "cannot create NAT user")
 
 typedef enum
 {
@@ -130,13 +119,13 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
       if (clib_bihash_add_del_8_8 (&tsm->in2out, &s_kv, 0))
        nat_elog_warn ("out2in key del failed");
 
-      snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
-                                          s->in2out.addr.as_u32,
-                                          s->out2in.addr.as_u32,
-                                          s->nat_proto,
-                                          s->in2out.port,
-                                          s->out2in.port,
-                                          s->in2out.fib_index);
+      nat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
+                                         s->in2out.addr.as_u32,
+                                         s->out2in.addr.as_u32,
+                                         s->nat_proto,
+                                         s->in2out.port,
+                                         s->out2in.port,
+                                         s->in2out.fib_index);
 
       nat_syslog_nat44_apmdel (s->user_index, s->in2out.fib_index,
                               &s->in2out.addr, s->in2out.port,
@@ -206,7 +195,7 @@ create_session_for_static_mapping (snat_main_t * sm,
   u = nat_user_get_or_create (sm, &i2o_addr, i2o_fib_index, thread_index);
   if (!u)
     {
-      nat_elog_warn ("create NAT user failed");
+      b0->error = node->errors[SNAT_OUT2IN_ERROR_CANNOT_CREATE_USER];
       return 0;
     }
 
@@ -246,12 +235,12 @@ create_session_for_static_mapping (snat_main_t * sm,
     nat_elog_notice ("out2in key add failed");
 
   /* log NAT event */
-  snat_ipfix_logging_nat44_ses_create (thread_index,
-                                      s->in2out.addr.as_u32,
-                                      s->out2in.addr.as_u32,
-                                      s->nat_proto,
-                                      s->in2out.port,
-                                      s->out2in.port, s->in2out.fib_index);
+  nat_ipfix_logging_nat44_ses_create (thread_index,
+                                     s->in2out.addr.as_u32,
+                                     s->out2in.addr.as_u32,
+                                     s->nat_proto,
+                                     s->in2out.port,
+                                     s->out2in.port, s->in2out.fib_index);
 
   nat_syslog_nat44_apmadd (s->user_index, s->in2out.fib_index,
                           &s->in2out.addr, s->in2out.port, &s->out2in.addr,
@@ -369,7 +358,7 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
       if (snat_static_mapping_match
          (sm, *addr, *port, *fib_index, *proto,
           &mapping_addr, &mapping_port, &mapping_fib_index, 1, &is_addr_only,
-          0, 0, 0, &identity_nat))
+          0, 0, 0, &identity_nat, 0))
        {
          if (!sm->forwarding_enabled)
            {
@@ -495,7 +484,7 @@ icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
     }
   if (snat_static_mapping_match
       (sm, addr, port, rx_fib_index0, *proto, mapping_addr, mapping_port,
-       mapping_fib_index, 1, &is_addr_only, 0, 0, 0, 0))
+       mapping_fib_index, 1, &is_addr_only, 0, 0, 0, 0, 0))
     {
       /* Don't NAT packet aimed at the intfc address */
       if (is_interface_addr (sm, node, sw_if_index0, ip0->dst_address.as_u32))
@@ -725,684 +714,658 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame)
 {
-  u32 n_left_from, *from, *to_next;
-  snat_out2in_next_t next_index;
-  u32 pkts_processed = 0;
+  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;
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
-  next_index = node->cached_next_index;
 
-  while (n_left_from > 0)
+  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 >= 2)
     {
-      u32 n_left_to_next;
+      vlib_buffer_t *b0, *b1;
+      u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
+      u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
+      u32 sw_if_index0, sw_if_index1;
+      ip4_header_t *ip0, *ip1;
+      ip_csum_t sum0, sum1;
+      u32 new_addr0, old_addr0;
+      u16 new_port0, old_port0;
+      u32 new_addr1, old_addr1;
+      u16 new_port1, old_port1;
+      udp_header_t *udp0, *udp1;
+      tcp_header_t *tcp0, *tcp1;
+      icmp46_header_t *icmp0, *icmp1;
+      u32 rx_fib_index0, rx_fib_index1;
+      u32 proto0, proto1;
+      snat_session_t *s0 = 0, *s1 = 0;
+      clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
+      u8 identity_nat0, identity_nat1;
+      ip4_address_t sm_addr0, sm_addr1;
+      u16 sm_port0, sm_port1;
+      u32 sm_fib_index0, sm_fib_index1;
+
+      b0 = *b;
+      b++;
+      b1 = *b;
+      b++;
+
+      /* Prefetch next iteration. */
+      if (PREDICT_TRUE (n_left_from >= 4))
+       {
+         vlib_buffer_t *p2, *p3;
+
+         p2 = *b;
+         p3 = *(b + 1);
+
+         vlib_prefetch_buffer_header (p2, LOAD);
+         vlib_prefetch_buffer_header (p3, LOAD);
+
+         CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
+         CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
+       }
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      vnet_buffer (b0)->snat.flags = 0;
+      vnet_buffer (b1)->snat.flags = 0;
 
-      while (n_left_from >= 4 && n_left_to_next >= 2)
+      ip0 = vlib_buffer_get_current (b0);
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      icmp0 = (icmp46_header_t *) udp0;
+
+      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
+                              sw_if_index0);
+
+      if (PREDICT_FALSE (ip0->ttl == 1))
        {
-         u32 bi0, bi1;
-         vlib_buffer_t *b0, *b1;
-         u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
-         u32 next1 = SNAT_OUT2IN_NEXT_LOOKUP;
-         u32 sw_if_index0, sw_if_index1;
-         ip4_header_t *ip0, *ip1;
-         ip_csum_t sum0, sum1;
-         u32 new_addr0, old_addr0;
-         u16 new_port0, old_port0;
-         u32 new_addr1, old_addr1;
-         u16 new_port1, old_port1;
-         udp_header_t *udp0, *udp1;
-         tcp_header_t *tcp0, *tcp1;
-         icmp46_header_t *icmp0, *icmp1;
-         u32 rx_fib_index0, rx_fib_index1;
-         u32 proto0, proto1;
-         snat_session_t *s0 = 0, *s1 = 0;
-         clib_bihash_kv_8_8_t kv0, kv1, value0, value1;
-         u8 identity_nat0, identity_nat1;
-         ip4_address_t sm_addr0, sm_addr1;
-         u16 sm_port0, sm_port1;
-         u32 sm_fib_index0, sm_fib_index1;
-
-         /* Prefetch next iteration. */
-         {
-           vlib_buffer_t *p2, *p3;
-
-           p2 = vlib_get_buffer (vm, from[2]);
-           p3 = vlib_get_buffer (vm, from[3]);
-
-           vlib_prefetch_buffer_header (p2, LOAD);
-           vlib_prefetch_buffer_header (p3, LOAD);
-
-           CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
-           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, LOAD);
-         }
-
-         /* speculatively enqueue b0 and b1 to the current next frame */
-         to_next[0] = bi0 = from[0];
-         to_next[1] = bi1 = from[1];
-         from += 2;
-         to_next += 2;
-         n_left_from -= 2;
-         n_left_to_next -= 2;
-
-         b0 = vlib_get_buffer (vm, bi0);
-         b1 = vlib_get_buffer (vm, bi1);
-
-         vnet_buffer (b0)->snat.flags = 0;
-         vnet_buffer (b1)->snat.flags = 0;
-
-         ip0 = vlib_buffer_get_current (b0);
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-
-         sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-         rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-                                  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 = SNAT_OUT2IN_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);
+         next0 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+         goto trace0;
+       }
 
-         proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       {
+         if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
            {
-             if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+             if (!sm->forwarding_enabled)
                {
-                 if (!sm->forwarding_enabled)
-                   {
-                     b0->error =
-                       node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 b0->error =
+                   node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                 next0 = SNAT_OUT2IN_NEXT_DROP;
                }
-             other_packets++;
-             goto trace0;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index0, 1);
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
-           {
-             next0 = icmp_out2in_slow_path
-               (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                next0, now, thread_index, &s0);
-             icmp_packets++;
-             goto trace0;
-           }
+         goto trace0;
+       }
 
-         init_nat_k (&kv0, ip0->dst_address,
-                     vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
-                     proto0);
-         if (clib_bihash_search_8_8
-             (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next0 = icmp_out2in_slow_path
+           (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+            next0, now, thread_index, &s0);
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+                                        thread_index, sw_if_index0, 1);
+         goto trace0;
+       }
+
+      init_nat_k (&kv0, ip0->dst_address,
+                 vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+                 proto0);
+      if (clib_bihash_search_8_8
+         (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+       {
+         /* 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_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
+              0, &identity_nat0, 0))
            {
-             /* 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_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
-                  0, &identity_nat0))
+             /*
+              * 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))))
                {
-                 /*
-                  * 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))))
-                   {
-                     vnet_feature_next (&next0, b0);
-                     goto trace0;
-                   }
-
-                 if (!sm->forwarding_enabled)
-                   {
-                     b0->error =
-                       node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 vnet_feature_next (&next0, b0);
                  goto trace0;
                }
 
-             if (PREDICT_FALSE (identity_nat0))
-               goto trace0;
-
-             /* Create session initiated by host from external network */
-             s0 = create_session_for_static_mapping (sm, b0,
-                                                     sm_addr0, sm_port0,
-                                                     sm_fib_index0,
-                                                     ip0->dst_address,
-                                                     vnet_buffer (b0)->
-                                                     ip.reass.l4_dst_port,
-                                                     rx_fib_index0, proto0,
-                                                     node, thread_index,
-                                                     now);
-             if (!s0)
+             if (!sm->forwarding_enabled)
                {
+                 b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                  next0 = SNAT_OUT2IN_NEXT_DROP;
-                 goto trace0;
                }
+             goto trace0;
            }
-         else
-           s0 = pool_elt_at_index (tsm->sessions, value0.value);
 
-         old_addr0 = ip0->dst_address.as_u32;
-         ip0->dst_address = s0->in2out.addr;
-         new_addr0 = ip0->dst_address.as_u32;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+         if (PREDICT_FALSE (identity_nat0))
+           goto trace0;
+
+         /* Create session initiated by host from external network */
+         s0 = create_session_for_static_mapping (sm, b0,
+                                                 sm_addr0, sm_port0,
+                                                 sm_fib_index0,
+                                                 ip0->dst_address,
+                                                 vnet_buffer (b0)->ip.
+                                                 reass.l4_dst_port,
+                                                 rx_fib_index0, proto0, node,
+                                                 thread_index, now);
+         if (!s0)
+           {
+             next0 = SNAT_OUT2IN_NEXT_DROP;
+             goto trace0;
+           }
+       }
+      else
+       s0 = pool_elt_at_index (tsm->sessions, value0.value);
 
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                ip4_header_t,
-                                dst_address /* changed member */ );
-         ip0->checksum = ip_csum_fold (sum0);
+      old_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address = s0->in2out.addr;
+      new_addr0 = ip0->dst_address.as_u32;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
 
-         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                            ip4_header_t, dst_address /* changed member */ );
+      ip0->checksum = ip_csum_fold (sum0);
+
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
-                 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 /* changed member */ );
-
-                 sum0 = ip_csum_update (sum0, old_port0, new_port0,
-                                        ip4_header_t /* cheat */ ,
-                                        length /* changed member */ );
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
+             old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+             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 /* changed member */ );
+
+             sum0 = ip_csum_update (sum0, old_port0, new_port0,
+                                    ip4_header_t /* cheat */ ,
+                                    length /* changed member */ );
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+                                        thread_index, sw_if_index0, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+             old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+             new_port0 = udp0->dst_port = s0->in2out.port;
+             if (PREDICT_FALSE (udp0->checksum))
                {
-                 old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 if (PREDICT_FALSE (udp0->checksum))
-                   {
-                     sum0 = udp0->checksum;
-                     sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
-                       );
-                     sum0 =
-                       ip_csum_update (sum0, old_port0, new_port0,
-                                       ip4_header_t /* cheat */ ,
-                                       length /* changed member */ );
-                     udp0->checksum = ip_csum_fold (sum0);
-                   }
+                 sum0 = udp0->checksum;
+                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
+                   );
+                 sum0 =
+                   ip_csum_update (sum0, old_port0, new_port0,
+                                   ip4_header_t /* cheat */ ,
+                                   length /* changed member */ );
+                 udp0->checksum = ip_csum_fold (sum0);
                }
-             udp_packets++;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.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);
-       trace0:
+      /* 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)))
-           {
-             snat_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
-             t->session_index = ~0;
-             if (s0)
-               t->session_index =
-                 s0 - sm->per_thread_data[thread_index].sessions;
-           }
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+         t->sw_if_index = sw_if_index0;
+         t->next_index = next0;
+         t->session_index = ~0;
+         if (s0)
+           t->session_index =
+             s0 - sm->per_thread_data[thread_index].sessions;
+       }
 
-         pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
+      if (next0 == SNAT_OUT2IN_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+                                        thread_index, sw_if_index0, 1);
+       }
 
 
-         ip1 = vlib_buffer_get_current (b1);
-         udp1 = ip4_next_header (ip1);
-         tcp1 = (tcp_header_t *) udp1;
-         icmp1 = (icmp46_header_t *) udp1;
+      ip1 = vlib_buffer_get_current (b1);
+      udp1 = ip4_next_header (ip1);
+      tcp1 = (tcp_header_t *) udp1;
+      icmp1 = (icmp46_header_t *) udp1;
 
-         sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
-         rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-                                  sw_if_index1);
+      sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_RX];
+      rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
+                              sw_if_index1);
 
-         if (PREDICT_FALSE (ip1->ttl == 1))
-           {
-             vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
-             icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
-                                          ICMP4_time_exceeded_ttl_exceeded_in_transit,
-                                          0);
-             next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
-             goto trace1;
-           }
+      if (PREDICT_FALSE (ip1->ttl == 1))
+       {
+         vnet_buffer (b1)->sw_if_index[VLIB_TX] = (u32) ~ 0;
+         icmp4_error_set_vnet_buffer (b1, ICMP4_time_exceeded,
+                                      ICMP4_time_exceeded_ttl_exceeded_in_transit,
+                                      0);
+         next1 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+         goto trace1;
+       }
 
-         proto1 = ip_proto_to_nat_proto (ip1->protocol);
+      proto1 = ip_proto_to_nat_proto (ip1->protocol);
 
-         if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
+      if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_OTHER))
+       {
+         if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
            {
-             if (nat_out2in_sm_unknown_proto (sm, b1, ip1, rx_fib_index1))
+             if (!sm->forwarding_enabled)
                {
-                 if (!sm->forwarding_enabled)
-                   {
-                     b1->error =
-                       node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-                     next1 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 b1->error =
+                   node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                 next1 = SNAT_OUT2IN_NEXT_DROP;
                }
-             other_packets++;
-             goto trace1;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index1, 1);
+         goto trace1;
+       }
 
-         if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
-           {
-             next1 = icmp_out2in_slow_path
-               (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
-                next1, now, thread_index, &s1);
-             icmp_packets++;
-             goto trace1;
-           }
+      if (PREDICT_FALSE (proto1 == NAT_PROTOCOL_ICMP))
+       {
+         next1 = icmp_out2in_slow_path
+           (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
+            next1, now, thread_index, &s1);
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+                                        thread_index, sw_if_index1, 1);
+         goto trace1;
+       }
 
-         init_nat_k (&kv1, ip1->dst_address,
-                     vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
-                     proto1);
+      init_nat_k (&kv1, ip1->dst_address,
+                 vnet_buffer (b1)->ip.reass.l4_dst_port, rx_fib_index1,
+                 proto1);
 
-         if (clib_bihash_search_8_8
-             (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
+      if (clib_bihash_search_8_8
+         (&sm->per_thread_data[thread_index].out2in, &kv1, &value1))
+       {
+         /* Try to match static mapping by external address and port,
+            destination address and port in packet */
+         if (snat_static_mapping_match
+             (sm, ip1->dst_address,
+              vnet_buffer (b1)->ip.reass.l4_dst_port, proto1,
+              rx_fib_index1, &sm_addr1, &sm_port1, &sm_fib_index1, 1, 0,
+              0, 0, 0, &identity_nat1, 0))
            {
-             /* Try to match static mapping by external address and port,
-                destination address and port in packet */
-             if (snat_static_mapping_match
-                 (sm, ip1->dst_address,
-                  vnet_buffer (b1)->ip.reass.l4_dst_port, proto1,
-                  rx_fib_index1, &sm_addr1, &sm_port1, &sm_fib_index1, 1, 0,
-                  0, 0, 0, &identity_nat1))
+             /*
+              * Send DHCP packets to the ipv4 stack, or we won't
+              * be able to use dhcp client on the outside interface
+              */
+             if (PREDICT_FALSE
+                 (proto1 == NAT_PROTOCOL_UDP
+                  && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
+                      clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_client))))
                {
-                 /*
-                  * Send DHCP packets to the ipv4 stack, or we won't
-                  * be able to use dhcp client on the outside interface
-                  */
-                 if (PREDICT_FALSE
-                     (proto1 == NAT_PROTOCOL_UDP
-                      && (vnet_buffer (b1)->ip.reass.l4_dst_port ==
-                          clib_host_to_net_u16
-                          (UDP_DST_PORT_dhcp_to_client))))
-                   {
-                     vnet_feature_next (&next1, b1);
-                     goto trace1;
-                   }
-
-                 if (!sm->forwarding_enabled)
-                   {
-                     b1->error =
-                       node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-                     next1 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 vnet_feature_next (&next1, b1);
                  goto trace1;
                }
 
-             if (PREDICT_FALSE (identity_nat1))
-               goto trace1;
-
-             /* Create session initiated by host from external network */
-             s1 =
-               create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
-                                                  sm_fib_index1,
-                                                  ip1->dst_address,
-                                                  vnet_buffer (b1)->ip.
-                                                  reass.l4_dst_port,
-                                                  rx_fib_index1, proto1,
-                                                  node, thread_index, now);
-             if (!s1)
+             if (!sm->forwarding_enabled)
                {
+                 b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                  next1 = SNAT_OUT2IN_NEXT_DROP;
-                 goto trace1;
                }
+             goto trace1;
            }
-         else
-           s1 =
-             pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-                                value1.value);
-
-         old_addr1 = ip1->dst_address.as_u32;
-         ip1->dst_address = s1->in2out.addr;
-         new_addr1 = ip1->dst_address.as_u32;
-         vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
-
-         sum1 = ip1->checksum;
-         sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
-                                ip4_header_t,
-                                dst_address /* changed member */ );
-         ip1->checksum = ip_csum_fold (sum1);
-
-         if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
+
+         if (PREDICT_FALSE (identity_nat1))
+           goto trace1;
+
+         /* Create session initiated by host from external network */
+         s1 =
+           create_session_for_static_mapping (sm, b1, sm_addr1, sm_port1,
+                                              sm_fib_index1,
+                                              ip1->dst_address,
+                                              vnet_buffer (b1)->ip.
+                                              reass.l4_dst_port,
+                                              rx_fib_index1, proto1, node,
+                                              thread_index, now);
+         if (!s1)
            {
-             if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
-               {
-                 old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
-                 new_port1 = udp1->dst_port = s1->in2out.port;
-
-                 sum1 = tcp1->checksum;
-                 sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
-                                        ip4_header_t,
-                                        dst_address /* changed member */ );
-
-                 sum1 = ip_csum_update (sum1, old_port1, new_port1,
-                                        ip4_header_t /* cheat */ ,
-                                        length /* changed member */ );
-                 tcp1->checksum = ip_csum_fold (sum1);
-               }
-             tcp_packets++;
+             next1 = SNAT_OUT2IN_NEXT_DROP;
+             goto trace1;
            }
-         else
+       }
+      else
+       s1 =
+         pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+                            value1.value);
+
+      old_addr1 = ip1->dst_address.as_u32;
+      ip1->dst_address = s1->in2out.addr;
+      new_addr1 = ip1->dst_address.as_u32;
+      vnet_buffer (b1)->sw_if_index[VLIB_TX] = s1->in2out.fib_index;
+
+      sum1 = ip1->checksum;
+      sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
+                            ip4_header_t, dst_address /* changed member */ );
+      ip1->checksum = ip_csum_fold (sum1);
+
+      if (PREDICT_TRUE (proto1 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
            {
-             if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
+             old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
+             new_port1 = udp1->dst_port = s1->in2out.port;
+
+             sum1 = tcp1->checksum;
+             sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
+                                    ip4_header_t,
+                                    dst_address /* changed member */ );
+
+             sum1 = ip_csum_update (sum1, old_port1, new_port1,
+                                    ip4_header_t /* cheat */ ,
+                                    length /* changed member */ );
+             tcp1->checksum = ip_csum_fold (sum1);
+           }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+                                        thread_index, sw_if_index1, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b1)->ip.reass.is_non_first_fragment)
+           {
+             old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
+             new_port1 = udp1->dst_port = s1->in2out.port;
+             if (PREDICT_FALSE (udp1->checksum))
                {
-                 old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
-                 new_port1 = udp1->dst_port = s1->in2out.port;
-                 if (PREDICT_FALSE (udp1->checksum))
-                   {
-
-                     sum1 = udp1->checksum;
-                     sum1 =
-                       ip_csum_update (sum1, old_addr1, new_addr1,
-                                       ip4_header_t,
-                                       dst_address /* changed member */ );
-                     sum1 =
-                       ip_csum_update (sum1, old_port1, new_port1,
-                                       ip4_header_t /* cheat */ ,
-                                       length /* changed member */ );
-                     udp1->checksum = ip_csum_fold (sum1);
-                   }
+
+                 sum1 = udp1->checksum;
+                 sum1 =
+                   ip_csum_update (sum1, old_addr1, new_addr1,
+                                   ip4_header_t,
+                                   dst_address /* changed member */ );
+                 sum1 =
+                   ip_csum_update (sum1, old_port1, new_port1,
+                                   ip4_header_t /* cheat */ ,
+                                   length /* changed member */ );
+                 udp1->checksum = ip_csum_fold (sum1);
                }
-             udp_packets++;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
+                                        thread_index, sw_if_index1, 1);
+       }
 
-         /* Accounting */
-         nat44_session_update_counters (s1, now,
-                                        vlib_buffer_length_in_chain (vm, b1),
-                                        thread_index);
-         /* Per-user LRU list maintenance */
-         nat44_session_update_lru (sm, s1, thread_index);
-       trace1:
-
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b1->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             snat_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b1, sizeof (*t));
-             t->sw_if_index = sw_if_index1;
-             t->next_index = next1;
-             t->session_index = ~0;
-             if (s1)
-               t->session_index =
-                 s1 - sm->per_thread_data[thread_index].sessions;
-           }
+      /* Accounting */
+      nat44_session_update_counters (s1, now,
+                                    vlib_buffer_length_in_chain (vm, b1),
+                                    thread_index);
+      /* Per-user LRU list maintenance */
+      nat44_session_update_lru (sm, s1, thread_index);
+    trace1:
 
-         pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b1->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         snat_out2in_trace_t *t = vlib_add_trace (vm, node, b1, sizeof (*t));
+         t->sw_if_index = sw_if_index1;
+         t->next_index = next1;
+         t->session_index = ~0;
+         if (s1)
+           t->session_index =
+             s1 - sm->per_thread_data[thread_index].sessions;
+       }
 
-         /* verify speculative enqueues, maybe switch current next frame */
-         vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
-                                          to_next, n_left_to_next,
-                                          bi0, bi1, next0, next1);
+      if (next1 == SNAT_OUT2IN_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+                                        thread_index, sw_if_index1, 1);
        }
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      n_left_from -= 2;
+      next[0] = next0;
+      next[1] = next1;
+      next += 2;
+    }
+
+  while (n_left_from > 0)
+    {
+      vlib_buffer_t *b0;
+      u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
+      u32 sw_if_index0;
+      ip4_header_t *ip0;
+      ip_csum_t sum0;
+      u32 new_addr0, old_addr0;
+      u16 new_port0, old_port0;
+      udp_header_t *udp0;
+      tcp_header_t *tcp0;
+      icmp46_header_t *icmp0;
+      u32 rx_fib_index0;
+      u32 proto0;
+      snat_session_t *s0 = 0;
+      clib_bihash_kv_8_8_t kv0, value0;
+      u8 identity_nat0;
+      ip4_address_t sm_addr0;
+      u16 sm_port0;
+      u32 sm_fib_index0;
+
+      b0 = *b;
+      ++b;
+
+      vnet_buffer (b0)->snat.flags = 0;
+
+      ip0 = vlib_buffer_get_current (b0);
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      icmp0 = (icmp46_header_t *) udp0;
+
+      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
+                              sw_if_index0);
+
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
+
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
        {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0 = SNAT_OUT2IN_NEXT_LOOKUP;
-         u32 sw_if_index0;
-         ip4_header_t *ip0;
-         ip_csum_t sum0;
-         u32 new_addr0, old_addr0;
-         u16 new_port0, old_port0;
-         udp_header_t *udp0;
-         tcp_header_t *tcp0;
-         icmp46_header_t *icmp0;
-         u32 rx_fib_index0;
-         u32 proto0;
-         snat_session_t *s0 = 0;
-         clib_bihash_kv_8_8_t kv0, value0;
-         u8 identity_nat0;
-         ip4_address_t sm_addr0;
-         u16 sm_port0;
-         u32 sm_fib_index0;
-
-         /* 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);
-
-         vnet_buffer (b0)->snat.flags = 0;
-
-         ip0 = vlib_buffer_get_current (b0);
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-
-         sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-         rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index,
-                                  sw_if_index0);
-
-         proto0 = ip_proto_to_nat_proto (ip0->protocol);
-
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+         if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
            {
-             if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
+             if (!sm->forwarding_enabled)
                {
-                 if (!sm->forwarding_enabled)
-                   {
-                     b0->error =
-                       node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 b0->error =
+                   node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                 next0 = SNAT_OUT2IN_NEXT_DROP;
                }
-             other_packets++;
-             goto trace00;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index0, 1);
+         goto trace00;
+       }
 
-         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 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
-             goto trace00;
-           }
+      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 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+         goto trace00;
+       }
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
-           {
-             next0 = icmp_out2in_slow_path
-               (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                next0, now, thread_index, &s0);
-             icmp_packets++;
-             goto trace00;
-           }
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next0 = icmp_out2in_slow_path
+           (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
+            next0, now, thread_index, &s0);
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.icmp,
+                                        thread_index, sw_if_index0, 1);
+         goto trace00;
+       }
 
-         init_nat_k (&kv0, ip0->dst_address,
-                     vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
-                     proto0);
+      init_nat_k (&kv0, ip0->dst_address,
+                 vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+                 proto0);
 
-         if (clib_bihash_search_8_8
-             (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+      if (clib_bihash_search_8_8
+         (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+       {
+         /* 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_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
+              0, &identity_nat0, 0))
            {
-             /* 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_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0,
-                  0, &identity_nat0))
+             /*
+              * 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))))
                {
-                 /*
-                  * 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))))
-                   {
-                     vnet_feature_next (&next0, b0);
-                     goto trace00;
-                   }
-
-                 if (!sm->forwarding_enabled)
-                   {
-                     b0->error =
-                       node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                   }
+                 vnet_feature_next (&next0, b0);
                  goto trace00;
                }
 
-             if (PREDICT_FALSE (identity_nat0))
-               goto trace00;
-
-             /* Create session initiated by host from external network */
-             s0 = create_session_for_static_mapping (sm, b0,
-                                                     sm_addr0, sm_port0,
-                                                     sm_fib_index0,
-                                                     ip0->dst_address,
-                                                     vnet_buffer (b0)->
-                                                     ip.reass.l4_dst_port,
-                                                     rx_fib_index0, proto0,
-                                                     node, thread_index,
-                                                     now);
-             if (!s0)
+             if (!sm->forwarding_enabled)
                {
+                 b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                  next0 = SNAT_OUT2IN_NEXT_DROP;
-                 goto trace00;
                }
+             goto trace00;
            }
-         else
-           s0 =
-             pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-                                value0.value);
 
-         old_addr0 = ip0->dst_address.as_u32;
-         ip0->dst_address = s0->in2out.addr;
-         new_addr0 = ip0->dst_address.as_u32;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->in2out.fib_index;
+         if (PREDICT_FALSE (identity_nat0))
+           goto trace00;
 
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                ip4_header_t,
-                                dst_address /* changed member */ );
-         ip0->checksum = ip_csum_fold (sum0);
+         /* Create session initiated by host from external network */
+         s0 = create_session_for_static_mapping (sm, b0,
+                                                 sm_addr0, sm_port0,
+                                                 sm_fib_index0,
+                                                 ip0->dst_address,
+                                                 vnet_buffer (b0)->ip.
+                                                 reass.l4_dst_port,
+                                                 rx_fib_index0, proto0, node,
+                                                 thread_index, now);
+         if (!s0)
+           {
+             next0 = SNAT_OUT2IN_NEXT_DROP;
+             goto trace00;
+           }
+       }
+      else
+       s0 =
+         pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
+                            value0.value);
 
-         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+      old_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address = s0->in2out.addr;
+      new_addr0 = ip0->dst_address.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 /* changed member */ );
+      ip0->checksum = ip_csum_fold (sum0);
+
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
-                 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 /* changed member */ );
-
-                 sum0 = ip_csum_update (sum0, old_port0, new_port0,
-                                        ip4_header_t /* cheat */ ,
-                                        length /* changed member */ );
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
+             old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+             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 /* changed member */ );
+
+             sum0 = ip_csum_update (sum0, old_port0, new_port0,
+                                    ip4_header_t /* cheat */ ,
+                                    length /* changed member */ );
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.tcp,
+                                        thread_index, sw_if_index0, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+             old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
+             new_port0 = udp0->dst_port = s0->in2out.port;
+             if (PREDICT_FALSE (udp0->checksum))
                {
-                 old_port0 = vnet_buffer (b0)->ip.reass.l4_dst_port;
-                 new_port0 = udp0->dst_port = s0->in2out.port;
-                 if (PREDICT_FALSE (udp0->checksum))
-                   {
-                     sum0 = udp0->checksum;
-                     sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address      /* changed member */
-                       );
-                     sum0 =
-                       ip_csum_update (sum0, old_port0, new_port0,
-                                       ip4_header_t /* cheat */ ,
-                                       length /* changed member */ );
-                     udp0->checksum = ip_csum_fold (sum0);
-                   }
+                 sum0 = udp0->checksum;
+                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t, dst_address  /* changed member */
+                   );
+                 sum0 =
+                   ip_csum_update (sum0, old_port0, new_port0,
+                                   ip4_header_t /* cheat */ ,
+                                   length /* changed member */ );
+                 udp0->checksum = ip_csum_fold (sum0);
                }
-             udp_packets++;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.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);
-       trace00:
-
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             snat_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
-             t->session_index = ~0;
-             if (s0)
-               t->session_index =
-                 s0 - sm->per_thread_data[thread_index].sessions;
-           }
+      /* 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);
+    trace00:
 
-         pkts_processed += next0 == SNAT_OUT2IN_NEXT_LOOKUP;
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+         t->sw_if_index = sw_if_index0;
+         t->next_index = next0;
+         t->session_index = ~0;
+         if (s0)
+           t->session_index =
+             s0 - sm->per_thread_data[thread_index].sessions;
+       }
 
-         /* 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 (next0 == SNAT_OUT2IN_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.drops,
+                                        thread_index, sw_if_index0, 1);
        }
 
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+      n_left_from--;
+      next[0] = next0;
+      next++;
     }
 
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_TCP_PACKETS, tcp_packets);
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_UDP_PACKETS, udp_packets);
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_ICMP_PACKETS, icmp_packets);
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_OTHER_PACKETS,
-                              other_packets);
-  vlib_node_increment_counter (vm, sm->out2in_node_index,
-                              SNAT_OUT2IN_ERROR_FRAGMENTS, fragments);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
 
   return frame->n_vectors;
 }
@@ -1434,176 +1397,159 @@ VLIB_NODE_FN (snat_out2in_fast_node) (vlib_main_t * vm,
                                      vlib_node_runtime_t * node,
                                      vlib_frame_t * frame)
 {
-  u32 n_left_from, *from, *to_next;
-  snat_out2in_next_t next_index;
-  u32 pkts_processed = 0;
+  u32 n_left_from, *from;
   snat_main_t *sm = &snat_main;
 
   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 next0 = SNAT_OUT2IN_NEXT_DROP;
+      u32 sw_if_index0;
+      ip4_header_t *ip0;
+      ip_csum_t sum0;
+      u32 new_addr0, old_addr0;
+      u16 new_port0, old_port0;
+      udp_header_t *udp0;
+      tcp_header_t *tcp0;
+      icmp46_header_t *icmp0;
+      u32 proto0;
+      u32 rx_fib_index0;
+      ip4_address_t sm_addr0;
+      u16 sm_port0;
+      u32 sm_fib_index0;
+
+      b0 = *b;
+      b++;
+
+      ip0 = vlib_buffer_get_current (b0);
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      icmp0 = (icmp46_header_t *) udp0;
+
+      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
+      rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
+
+      vnet_feature_next (&next0, b0);
+
+      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 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
+         goto trace00;
+       }
+
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       goto trace00;
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
        {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0 = SNAT_OUT2IN_NEXT_DROP;
-         u32 sw_if_index0;
-         ip4_header_t *ip0;
-         ip_csum_t sum0;
-         u32 new_addr0, old_addr0;
-         u16 new_port0, old_port0;
-         udp_header_t *udp0;
-         tcp_header_t *tcp0;
-         icmp46_header_t *icmp0;
-         u32 proto0;
-         u32 rx_fib_index0;
-         ip4_address_t sm_addr0;
-         u16 sm_port0;
-         u32 sm_fib_index0;
-
-         /* 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);
-
-         ip0 = vlib_buffer_get_current (b0);
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-
-         sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_RX];
-         rx_fib_index0 =
-           ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
-
-         vnet_feature_next (&next0, b0);
-
-         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 = SNAT_OUT2IN_NEXT_ICMP_ERROR;
-             goto trace00;
-           }
+         next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
+                              rx_fib_index0, node, next0, ~0, 0, 0);
+         goto trace00;
+       }
 
-         proto0 = ip_proto_to_nat_proto (ip0->protocol);
+      if (snat_static_mapping_match
+         (sm, ip0->dst_address, udp0->dst_port, rx_fib_index0, proto0,
+          &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0, 0, 0, 0))
+       {
+         b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+         goto trace00;
+       }
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
-           goto trace00;
+      new_addr0 = sm_addr0.as_u32;
+      new_port0 = sm_port0;
+      vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
+      old_addr0 = ip0->dst_address.as_u32;
+      ip0->dst_address.as_u32 = new_addr0;
 
-         if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
-           {
-             next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
-                                  rx_fib_index0, node, next0, ~0, 0, 0);
-             goto trace00;
-           }
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                            ip4_header_t, dst_address /* changed member */ );
+      ip0->checksum = ip_csum_fold (sum0);
 
-         if (snat_static_mapping_match
-             (sm, ip0->dst_address, udp0->dst_port, rx_fib_index0, proto0,
-              &sm_addr0, &sm_port0, &sm_fib_index0, 1, 0, 0, 0, 0, 0))
+      if (PREDICT_FALSE (new_port0 != udp0->dst_port))
+       {
+         old_port0 = udp0->dst_port;
+         udp0->dst_port = new_port0;
+
+         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
            {
-             b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-             goto trace00;
+             sum0 = tcp0->checksum;
+             sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                                    ip4_header_t,
+                                    dst_address /* changed member */ );
+             sum0 = ip_csum_update (sum0, old_port0, new_port0,
+                                    ip4_header_t /* cheat */ ,
+                                    length /* changed member */ );
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-
-         new_addr0 = sm_addr0.as_u32;
-         new_port0 = sm_port0;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm_fib_index0;
-         old_addr0 = ip0->dst_address.as_u32;
-         ip0->dst_address.as_u32 = new_addr0;
-
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                ip4_header_t,
-                                dst_address /* changed member */ );
-         ip0->checksum = ip_csum_fold (sum0);
-
-         if (PREDICT_FALSE (new_port0 != udp0->dst_port))
+         else if (udp0->checksum)
            {
-             old_port0 = udp0->dst_port;
-             udp0->dst_port = new_port0;
-
-             if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
-               {
-                 sum0 = tcp0->checksum;
-                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                        ip4_header_t,
-                                        dst_address /* changed member */ );
-                 sum0 = ip_csum_update (sum0, old_port0, new_port0,
-                                        ip4_header_t /* cheat */ ,
-                                        length /* changed member */ );
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             else if (udp0->checksum)
-               {
-                 sum0 = udp0->checksum;
-                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                        ip4_header_t,
-                                        dst_address /* changed member */ );
-                 sum0 = ip_csum_update (sum0, old_port0, new_port0,
-                                        ip4_header_t /* cheat */ ,
-                                        length /* changed member */ );
-                 udp0->checksum = ip_csum_fold (sum0);
-               }
+             sum0 = udp0->checksum;
+             sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                                    ip4_header_t,
+                                    dst_address /* changed member */ );
+             sum0 = ip_csum_update (sum0, old_port0, new_port0,
+                                    ip4_header_t /* cheat */ ,
+                                    length /* changed member */ );
+             udp0->checksum = ip_csum_fold (sum0);
            }
-         else
+       }
+      else
+       {
+         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
            {
-             if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
-               {
-                 sum0 = tcp0->checksum;
-                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                        ip4_header_t,
-                                        dst_address /* changed member */ );
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             else if (udp0->checksum)
-               {
-                 sum0 = udp0->checksum;
-                 sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                                        ip4_header_t,
-                                        dst_address /* changed member */ );
-                 udp0->checksum = ip_csum_fold (sum0);
-               }
+             sum0 = tcp0->checksum;
+             sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                                    ip4_header_t,
+                                    dst_address /* changed member */ );
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-
-       trace00:
-
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+         else if (udp0->checksum)
            {
-             snat_out2in_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
+             sum0 = udp0->checksum;
+             sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
+                                    ip4_header_t,
+                                    dst_address /* changed member */ );
+             udp0->checksum = ip_csum_fold (sum0);
            }
+       }
+
+    trace00:
 
-         pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         snat_out2in_trace_t *t = vlib_add_trace (vm, node, b0, sizeof (*t));
+         t->sw_if_index = sw_if_index0;
+         t->next_index = next0;
+       }
 
-         /* 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 (next0 == SNAT_OUT2IN_NEXT_DROP)
+       {
+         vlib_increment_simple_counter (&sm->counters.fastpath.out2in.drops,
+                                        vm->thread_index, sw_if_index0, 1);
        }
 
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+      n_left_from--;
+      next[0] = next0;
+      next++;
     }
 
-  vlib_node_increment_counter (vm, sm->out2in_fast_node_index,
-                              SNAT_OUT2IN_ERROR_OUT2IN_PACKETS,
-                              pkts_processed);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
+
   return frame->n_vectors;
 }