nat: cleanup & reorganization
[vpp.git] / src / plugins / nat / in2out_ed.c
index d78e552..5973d36 100644 (file)
 
 #include <vlib/vlib.h>
 #include <vnet/vnet.h>
-#include <vnet/pg/pg.h>
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/fib/ip4_fib.h>
-#include <vnet/udp/udp.h>
+#include <vnet/udp/udp_local.h>
 #include <vppinfra/error.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 <nat/nat44/ed_inlines.h>
+#include <nat/lib/nat_inlines.h>
+
+/* number of attempts to get a port for ED overloading algorithm, if rolling
+ * a dice this many times doesn't produce a free port, it's treated
+ * as if there were no free ports available to conserve resources */
+#define ED_PORT_ALLOC_ATTEMPTS (10)
 
 static char *nat_in2out_ed_error_strings[] = {
 #define _(sym,string) string,
@@ -79,11 +85,11 @@ nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
   clib_bihash_kv_16_8_t ed_kv;
   int i;
   snat_address_t *a;
-  snat_session_key_t key;
   snat_main_per_thread_data_t *tsm = vec_elt_at_index (sm->per_thread_data,
                                                       ctx->thread_index);
 
-  s = pool_elt_at_index (tsm->sessions, kv->value);
+  ASSERT (ctx->thread_index == ed_value_get_thread_index (kv));
+  s = pool_elt_at_index (tsm->sessions, ed_value_get_session_index (kv));
   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
   if (ctx->now >= sess_timeout_time)
     {
@@ -101,49 +107,50 @@ nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
        }
       else
        {
-         proto = snat_proto_to_ip_proto (s->in2out.protocol);
+         proto = nat_proto_to_ip_proto (s->nat_proto);
          l_port = s->out2in.port;
          r_port = s->ext_host_port;
        }
-      make_ed_kv (l_addr, r_addr, proto, fib_index, l_port, r_port, ~0ULL,
-                 &ed_kv);
-      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &ed_kv, 0))
+      init_ed_k (&ed_kv, *l_addr, l_port, *r_addr, r_port, fib_index, proto);
+      if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &ed_kv, 0))
        nat_elog_warn ("out2in_ed key del failed");
 
       if (snat_is_unk_proto_session (s))
        goto delete;
 
-      snat_ipfix_logging_nat44_ses_delete (ctx->thread_index,
-                                          s->in2out.addr.as_u32,
-                                          s->out2in.addr.as_u32,
-                                          s->in2out.protocol,
-                                          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_sdel (s->user_index, s->in2out.fib_index,
                             &s->in2out.addr, s->in2out.port,
                             &s->ext_host_nat_addr, s->ext_host_nat_port,
                             &s->out2in.addr, s->out2in.port,
                             &s->ext_host_addr, s->ext_host_port,
-                            s->in2out.protocol, is_twice_nat_session (s));
+                            s->nat_proto, is_twice_nat_session (s));
 
       nat_ha_sdel (&s->out2in.addr, s->out2in.port, &s->ext_host_addr,
-                  s->ext_host_port, s->out2in.protocol, s->out2in.fib_index,
+                  s->ext_host_port, s->nat_proto, s->out2in.fib_index,
                   ctx->thread_index);
 
       if (is_twice_nat_session (s))
        {
          for (i = 0; i < vec_len (sm->twice_nat_addresses); i++)
            {
-             key.protocol = s->in2out.protocol;
-             key.port = s->ext_host_nat_port;
+             // TODO FIXME this is obviously broken - which address should be
+             // freed here?!
              a = sm->twice_nat_addresses + i;
              if (a->addr.as_u32 == s->ext_host_nat_addr.as_u32)
                {
                  snat_free_outside_address_and_port (sm->twice_nat_addresses,
                                                      ctx->thread_index,
-                                                     &key);
+                                                     &s->ext_host_nat_addr,
+                                                     s->ext_host_nat_port,
+                                                     s->nat_proto);
                  break;
                }
            }
@@ -153,9 +160,10 @@ nat44_i2o_ed_is_idle_session_cb (clib_bihash_kv_16_8_t * kv, void *arg)
        goto delete;
 
       snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
-                                         &s->out2in);
+                                         &s->out2in.addr, s->out2in.port,
+                                         s->nat_proto);
     delete:
-      nat44_ed_delete_session (sm, s, ctx->thread_index, 1);
+      nat_ed_session_delete (sm, s, ctx->thread_index, 1);
       return 1;
     }
 
@@ -170,6 +178,8 @@ icmp_in2out_ed_slow_path (snat_main_t * sm, vlib_buffer_t * b0,
                          vlib_node_runtime_t * node, u32 next0, f64 now,
                          u32 thread_index, snat_session_t ** p_s0)
 {
+  vlib_main_t *vm = vlib_get_main ();
+
   next0 = icmp_in2out (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
                       next0, thread_index, p_s0, 0);
   snat_session_t *s0 = *p_s0;
@@ -178,34 +188,25 @@ icmp_in2out_ed_slow_path (snat_main_t * sm, vlib_buffer_t * b0,
       /* Accounting */
       nat44_session_update_counters (s0, now,
                                     vlib_buffer_length_in_chain
-                                    (sm->vlib_main, b0), thread_index);
+                                    (vm, b0), thread_index);
       /* Per-user LRU list maintenance */
       nat44_session_update_lru (sm, s0, thread_index);
     }
   return next0;
 }
 
-static_always_inline u16
-snat_random_port (u16 min, u16 max)
-{
-  snat_main_t *sm = &snat_main;
-  return min + random_u32 (&sm->random_seed) /
-    (random_u32_max () / (max - min + 1) + 1);
-}
-
 static int
 nat_ed_alloc_addr_and_port (snat_main_t * sm, u32 rx_fib_index,
-                           u32 snat_proto, u32 thread_index,
+                           u32 nat_proto, u32 thread_index,
                            ip4_address_t r_addr, u16 r_port, u8 proto,
                            u16 port_per_thread, u32 snat_thread_index,
                            snat_session_t * s,
-                           ip4_address_t * allocated_addr,
-                           u16 * allocated_port,
+                           ip4_address_t * outside_addr,
+                           u16 * outside_port,
                            clib_bihash_kv_16_8_t * out2in_ed_kv)
 {
   int i;
   snat_address_t *a, *ga = 0;
-  u32 portnum;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 
   const u16 port_thread_offset = (port_per_thread * snat_thread_index) + 1024;
@@ -213,42 +214,53 @@ nat_ed_alloc_addr_and_port (snat_main_t * sm, u32 rx_fib_index,
   for (i = 0; i < vec_len (sm->addresses); i++)
     {
       a = sm->addresses + i;
-      switch (snat_proto)
+      switch (nat_proto)
        {
-#define _(N, j, n, unused)                                                    \
-  case SNAT_PROTOCOL_##N:                                                     \
-    if (a->fib_index == rx_fib_index)                                         \
-      {                                                                       \
-        u16 port = snat_random_port (1, port_per_thread);                     \
-        u16 attempts = port_per_thread;                                       \
-        while (attempts > 0)                                                  \
-          {                                                                   \
-            --attempts;                                                       \
-            portnum = port_thread_offset + port;                              \
-            make_ed_kv (&a->addr, &r_addr, proto, s->out2in.fib_index,        \
-                        clib_host_to_net_u16 (portnum), r_port,               \
-                        s - tsm->sessions, out2in_ed_kv);                     \
-            int rv = clib_bihash_add_del_16_8 (&tsm->out2in_ed, out2in_ed_kv, \
-                                               2 /* is_add */);               \
-            if (0 == rv)                                                      \
-              {                                                               \
-                ++a->busy_##n##_port_refcounts[portnum];                      \
-                a->busy_##n##_ports_per_thread[thread_index]++;               \
-                a->busy_##n##_ports++;                                        \
-                *allocated_addr = a->addr;                                    \
-                *allocated_port = clib_host_to_net_u16 (portnum);             \
-                return 0;                                                     \
-              }                                                               \
-            port = (port + 1) % port_per_thread;                              \
-          }                                                                   \
-      }                                                                       \
-    else if (a->fib_index == ~0)                                              \
-      {                                                                       \
-        ga = a;                                                               \
-      }                                                                       \
+#define _(N, j, n, unused)                                                   \
+  case NAT_PROTOCOL_##N:                                                     \
+    if (a->fib_index == rx_fib_index)                                        \
+      {                                                                      \
+        /* first try port suggested by caller */                             \
+        u16 port = clib_net_to_host_u16 (*outside_port);                     \
+        u16 port_offset = port - port_thread_offset;                         \
+        if (port <= port_thread_offset ||                                    \
+            port > port_thread_offset + port_per_thread)                     \
+          {                                                                  \
+            /* need to pick a different port, suggested port doesn't fit in  \
+             * this thread's port range */                                   \
+            port_offset = snat_random_port (0, port_per_thread - 1);         \
+            port = port_thread_offset + port_offset;                         \
+          }                                                                  \
+        u16 attempts = ED_PORT_ALLOC_ATTEMPTS;                               \
+        do                                                                   \
+          {                                                                  \
+            init_ed_kv (out2in_ed_kv, a->addr, clib_host_to_net_u16 (port),  \
+                        r_addr, r_port, s->out2in.fib_index, proto,          \
+                        thread_index, s - tsm->sessions);                    \
+            int rv = clib_bihash_add_del_16_8 (&sm->out2in_ed, out2in_ed_kv, \
+                                               2 /* is_add */);              \
+            if (0 == rv)                                                     \
+              {                                                              \
+                ++a->busy_##n##_port_refcounts[port];                        \
+                a->busy_##n##_ports_per_thread[thread_index]++;              \
+                a->busy_##n##_ports++;                                       \
+                *outside_addr = a->addr;                                     \
+                *outside_port = clib_host_to_net_u16 (port);                 \
+                return 0;                                                    \
+              }                                                              \
+            port_offset = snat_random_port (0, port_per_thread - 1);         \
+            port = port_thread_offset + port_offset;                         \
+            --attempts;                                                      \
+          }                                                                  \
+        while (attempts > 0);                                                \
+      }                                                                      \
+    else if (a->fib_index == ~0)                                             \
+      {                                                                      \
+        ga = a;                                                              \
+      }                                                                      \
     break;
 
-         foreach_snat_protocol;
+         foreach_nat_protocol;
        default:
          nat_elog_info ("unknown protocol");
          return 1;
@@ -260,9 +272,9 @@ nat_ed_alloc_addr_and_port (snat_main_t * sm, u32 rx_fib_index,
       /* fake fib_index to reuse macro */
       rx_fib_index = ~0;
       a = ga;
-      switch (snat_proto)
+      switch (nat_proto)
        {
-         foreach_snat_protocol;
+         foreach_nat_protocol;
        default:
          nat_elog_info ("unknown protocol");
          return 1;
@@ -272,10 +284,38 @@ nat_ed_alloc_addr_and_port (snat_main_t * sm, u32 rx_fib_index,
 #undef _
 
   /* Totally out of translations to use... */
-  snat_ipfix_logging_addresses_exhausted (thread_index, 0);
+  nat_ipfix_logging_addresses_exhausted (thread_index, 0);
   return 1;
 }
 
+static_always_inline u32
+nat_outside_fib_index_lookup (snat_main_t * sm, ip4_address_t addr)
+{
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  nat_outside_fib_t *outside_fib;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {.ip4.as_u32 = addr.as_u32,}
+    ,
+  };
+  // TODO: multiple vrfs none can resolve addr
+  /* *INDENT-OFF* */
+  vec_foreach (outside_fib, sm->outside_fibs)
+    {
+      fei = fib_table_lookup (outside_fib->fib_index, &pfx);
+      if (FIB_NODE_INDEX_INVALID != fei)
+        {
+          if (fib_entry_get_resolving_interface (fei) != ~0)
+            {
+              return outside_fib->fib_index;
+            }
+        }
+    }
+  /* *INDENT-ON* */
+  return ~0;
+}
+
 static u32
 slow_path_ed (snat_main_t * sm,
              vlib_buffer_t * b,
@@ -288,26 +328,18 @@ slow_path_ed (snat_main_t * sm,
              snat_session_t ** sessionp,
              vlib_node_runtime_t * node, u32 next, u32 thread_index, f64 now)
 {
-  snat_session_t *s = NULL;
-  snat_session_key_t key0, key1;
-  lb_nat_type_t lb = 0;
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
-  u32 snat_proto = ip_proto_to_snat_proto (proto);
-  nat_outside_fib_t *outside_fib;
-  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
   clib_bihash_kv_16_8_t out2in_ed_kv;
-  bool out2in_ed_inserted = false;
-  ip4_address_t allocated_addr;
-  u16 allocated_port;
-  u8 identity_nat;
-  fib_prefix_t pfx = {
-    .fp_proto = FIB_PROTOCOL_IP4,
-    .fp_len = 32,
-    .fp_addr = {.ip4.as_u32 = r_addr.as_u32,},
-  };
   nat44_is_idle_session_ctx_t ctx;
+  ip4_address_t outside_addr;
+  u16 outside_port;
+  u8 identity_nat;
+
+  u32 nat_proto = ip_proto_to_nat_proto (proto);
+  snat_session_t *s = NULL;
+  lb_nat_type_t lb = 0;
 
-  if (PREDICT_TRUE (snat_proto == SNAT_PROTOCOL_TCP))
+  if (PREDICT_TRUE (nat_proto == NAT_PROTOCOL_TCP))
     {
       if (PREDICT_FALSE
          (!tcp_flags_is_init
@@ -318,34 +350,35 @@ slow_path_ed (snat_main_t * sm,
        }
     }
 
-  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE
+      (nat44_ed_maximum_sessions_exceeded (sm, rx_fib_index, thread_index)))
     {
-      if (!nat_global_lru_free_one (sm, thread_index, now))
+      if (!nat_lru_free_one (sm, thread_index, now))
        {
          b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
-         nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
+         nat_ipfix_logging_max_sessions (thread_index,
+                                         sm->max_translations_per_thread);
          nat_elog_notice ("maximum sessions exceeded");
          return NAT_NEXT_DROP;
        }
     }
 
-  key0.addr = l_addr;
-  key0.port = l_port;
-  key1.protocol = key0.protocol = snat_proto;
-  key0.fib_index = rx_fib_index;
-  key1.fib_index = sm->outside_fib_index;
-
+  ip4_address_t sm_addr;
+  u16 sm_port;
+  u32 sm_fib_index;
   /* First try to match static mapping by local address and port */
   if (snat_static_mapping_match
-      (sm, key0, &key1, 0, 0, 0, &lb, 0, &identity_nat))
+      (sm, l_addr, l_port, rx_fib_index, nat_proto, &sm_addr, &sm_port,
+       &sm_fib_index, 0, 0, 0, &lb, 0, &identity_nat, 0))
     {
-      s = nat_ed_session_alloc (sm, thread_index, now);
-      if (!s)
-       {
-         nat_elog_warn ("create NAT session failed");
-         b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
-         goto drop;
-       }
+      s = nat_ed_session_alloc (sm, thread_index, now, proto);
+      ASSERT (s);
+      s->in2out.addr = l_addr;
+      s->in2out.port = l_port;
+      s->nat_proto = nat_proto;
+      s->in2out.fib_index = rx_fib_index;
+      s->out2in.fib_index = sm->outside_fib_index;
+
       switch (vec_len (sm->outside_fibs))
        {
        case 0:
@@ -355,54 +388,43 @@ slow_path_ed (snat_main_t * sm,
          s->out2in.fib_index = sm->outside_fibs[0].fib_index;
          break;
        default:
-          /* *INDENT-OFF* */
-          vec_foreach (outside_fib, sm->outside_fibs)
-          {
-            fei = fib_table_lookup (outside_fib->fib_index, &pfx);
-            if (FIB_NODE_INDEX_INVALID != fei)
-              {
-                if (fib_entry_get_resolving_interface (fei) != ~0)
-                  {
-                    s->out2in.fib_index = outside_fib->fib_index;
-                    break;
-                  }
-              }
-          }
-          /* *INDENT-ON* */
+         s->out2in.fib_index = nat_outside_fib_index_lookup (sm, r_addr);
          break;
        }
 
       /* Try to create dynamic translation */
-      if (nat_ed_alloc_addr_and_port (sm, rx_fib_index, snat_proto,
+      outside_port = l_port;   // suggest using local port to allocation function
+      if (nat_ed_alloc_addr_and_port (sm, rx_fib_index, nat_proto,
                                      thread_index, r_addr, r_port, proto,
                                      sm->port_per_thread,
                                      tsm->snat_thread_index, s,
-                                     &allocated_addr,
-                                     &allocated_port, &out2in_ed_kv))
+                                     &outside_addr,
+                                     &outside_port, &out2in_ed_kv))
        {
          nat_elog_notice ("addresses exhausted");
          b->error = node->errors[NAT_IN2OUT_ED_ERROR_OUT_OF_PORTS];
-         goto drop;
+         nat_ed_session_delete (sm, s, thread_index, 1);
+         return NAT_NEXT_DROP;
        }
-
-      out2in_ed_inserted = true;
-      key1.addr = allocated_addr;
-      key1.port = allocated_port;
+      s->out2in.addr = outside_addr;
+      s->out2in.port = outside_port;
     }
   else
     {
       if (PREDICT_FALSE (identity_nat))
        {
-         *sessionp = s;
+         *sessionp = NULL;
          return next;
        }
-      s = nat_ed_session_alloc (sm, thread_index, now);
-      if (!s)
-       {
-         nat_elog_warn ("create NAT session failed");
-         b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
-         goto drop;
-       }
+      s = nat_ed_session_alloc (sm, thread_index, now, proto);
+      ASSERT (s);
+      s->out2in.addr = sm_addr;
+      s->out2in.port = sm_port;
+      s->in2out.addr = l_addr;
+      s->in2out.port = l_port;
+      s->nat_proto = nat_proto;
+      s->in2out.fib_index = rx_fib_index;
+      s->out2in.fib_index = sm->outside_fib_index;
       switch (vec_len (sm->outside_fibs))
        {
        case 0:
@@ -412,34 +434,19 @@ slow_path_ed (snat_main_t * sm,
          s->out2in.fib_index = sm->outside_fibs[0].fib_index;
          break;
        default:
-          /* *INDENT-OFF* */
-          vec_foreach (outside_fib, sm->outside_fibs)
-          {
-            fei = fib_table_lookup (outside_fib->fib_index, &pfx);
-            if (FIB_NODE_INDEX_INVALID != fei)
-              {
-                if (fib_entry_get_resolving_interface (fei) != ~0)
-                  {
-                    s->out2in.fib_index = outside_fib->fib_index;
-                    break;
-                  }
-              }
-          }
-          /* *INDENT-ON* */
+         s->out2in.fib_index = nat_outside_fib_index_lookup (sm, r_addr);
          break;
        }
 
       s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 
-
-      make_ed_kv (&key1.addr, &r_addr, proto,
-                 s->out2in.fib_index, key1.port, r_port, s - tsm->sessions,
-                 &out2in_ed_kv);
+      init_ed_kv (&out2in_ed_kv, sm_addr, sm_port, r_addr, r_port,
+                 s->out2in.fib_index, proto, thread_index,
+                 s - tsm->sessions);
       if (clib_bihash_add_or_overwrite_stale_16_8
-         (&tsm->out2in_ed, &out2in_ed_kv, nat44_o2i_ed_is_idle_session_cb,
+         (&sm->out2in_ed, &out2in_ed_kv, nat44_o2i_ed_is_idle_session_cb,
           &ctx))
        nat_elog_notice ("out2in-ed key add failed");
-      out2in_ed_inserted = true;
     }
 
   if (lb)
@@ -447,13 +454,10 @@ slow_path_ed (snat_main_t * sm,
   s->flags |= SNAT_SESSION_FLAG_ENDPOINT_DEPENDENT;
   s->ext_host_addr = r_addr;
   s->ext_host_port = r_port;
-  s->in2out = key0;
-  s->out2in = key1;
-  s->out2in.protocol = key0.protocol;
 
   clib_bihash_kv_16_8_t in2out_ed_kv;
-  make_ed_kv (&l_addr, &r_addr, proto, rx_fib_index, l_port, r_port,
-             s - tsm->sessions, &in2out_ed_kv);
+  init_ed_kv (&in2out_ed_kv, l_addr, l_port, r_addr, r_port, rx_fib_index,
+             proto, thread_index, s - tsm->sessions);
   ctx.now = now;
   ctx.thread_index = thread_index;
   if (clib_bihash_add_or_overwrite_stale_16_8 (&tsm->in2out_ed, &in2out_ed_kv,
@@ -464,39 +468,28 @@ slow_path_ed (snat_main_t * sm,
   *sessionp = s;
 
   /* log NAT event */
-  snat_ipfix_logging_nat44_ses_create (thread_index,
-                                      s->in2out.addr.as_u32,
-                                      s->out2in.addr.as_u32,
-                                      s->in2out.protocol,
-                                      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_sadd (s->user_index, s->in2out.fib_index,
                         &s->in2out.addr, s->in2out.port,
                         &s->ext_host_nat_addr, s->ext_host_nat_port,
                         &s->out2in.addr, s->out2in.port,
-                        &s->ext_host_addr, s->ext_host_port,
-                        s->in2out.protocol, 0);
+                        &s->ext_host_addr, s->ext_host_port, s->nat_proto,
+                        0);
 
   nat_ha_sadd (&s->in2out.addr, s->in2out.port, &s->out2in.addr,
               s->out2in.port, &s->ext_host_addr, s->ext_host_port,
               &s->ext_host_nat_addr, s->ext_host_nat_port,
-              s->in2out.protocol, s->in2out.fib_index, s->flags,
-              thread_index, 0);
+              s->nat_proto, s->in2out.fib_index, s->flags, thread_index, 0);
+
+  per_vrf_sessions_register_session (s, thread_index);
 
   return next;
-drop:
-  if (out2in_ed_inserted)
-    {
-      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &out2in_ed_kv, 0))
-       nat_elog_notice ("out2in-ed key del failed");
-    }
-  if (s)
-    {
-      nat_free_session_data (sm, s, thread_index, 0);
-      nat44_ed_delete_session (sm, s, thread_index, 1);
-    }
-  return NAT_NEXT_DROP;
 }
 
 static_always_inline int
@@ -505,23 +498,22 @@ nat44_ed_not_translate (snat_main_t * sm, vlib_node_runtime_t * node,
                        u32 rx_fib_index, u32 thread_index)
 {
   udp_header_t *udp = ip4_next_header (ip);
-  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
   clib_bihash_kv_16_8_t kv, value;
-  snat_session_key_t key0, key1;
 
-  make_ed_kv (&ip->dst_address, &ip->src_address, ip->protocol,
-             sm->outside_fib_index, udp->dst_port, udp->src_port, ~0ULL,
-             &kv);
+  init_ed_k (&kv, ip->dst_address, udp->dst_port, ip->src_address,
+            udp->src_port, sm->outside_fib_index, ip->protocol);
 
   /* NAT packet aimed at external address if has active sessions */
-  if (clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
+  if (clib_bihash_search_16_8 (&sm->out2in_ed, &kv, &value))
     {
-      key0.addr = ip->dst_address;
-      key0.port = udp->dst_port;
-      key0.protocol = proto;
-      key0.fib_index = sm->outside_fib_index;
       /* or is static mappings */
-      if (!snat_static_mapping_match (sm, key0, &key1, 1, 0, 0, 0, 0, 0))
+      ip4_address_t placeholder_addr;
+      u16 placeholder_port;
+      u32 placeholder_fib_index;
+      if (!snat_static_mapping_match
+         (sm, ip->dst_address, udp->dst_port, sm->outside_fib_index, proto,
+          &placeholder_addr, &placeholder_port, &placeholder_fib_index, 1, 0,
+          0, 0, 0, 0, 0))
        return 0;
     }
   else
@@ -548,31 +540,32 @@ nat_not_translate_output_feature_fwd (snat_main_t * sm, ip4_header_t * ip,
 
   if (ip->protocol == IP_PROTOCOL_ICMP)
     {
-      if (get_icmp_i2o_ed_key (b, ip, 0, ~0ULL, 0, 0, 0, &kv))
+      if (get_icmp_i2o_ed_key (b, ip, 0, ~0, ~0, 0, 0, 0, &kv))
        return 0;
     }
   else if (ip->protocol == IP_PROTOCOL_UDP || ip->protocol == IP_PROTOCOL_TCP)
     {
-      make_ed_kv (&ip->src_address, &ip->dst_address, ip->protocol, 0,
-                 vnet_buffer (b)->ip.reass.l4_src_port,
-                 vnet_buffer (b)->ip.reass.l4_dst_port, ~0ULL, &kv);
+      init_ed_k (&kv, ip->src_address, vnet_buffer (b)->ip.reass.l4_src_port,
+                ip->dst_address, vnet_buffer (b)->ip.reass.l4_dst_port, 0,
+                ip->protocol);
     }
   else
     {
-      make_ed_kv (&ip->src_address, &ip->dst_address, ip->protocol, 0, 0,
-                 0, ~0ULL, &kv);
+      init_ed_k (&kv, ip->src_address, 0, ip->dst_address, 0, 0,
+                ip->protocol);
     }
 
   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
     {
-      s = pool_elt_at_index (tsm->sessions, value.value);
+      ASSERT (thread_index == ed_value_get_thread_index (&value));
+      s =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&value));
       if (is_fwd_bypass_session (s))
        {
          if (ip->protocol == IP_PROTOCOL_TCP)
            {
-             if (nat44_set_tcp_session_state_i2o
-                 (sm, now, s, b, thread_index))
-               return 1;
+             nat44_set_tcp_session_state_i2o (sm, now, s, b, thread_index);
            }
          /* Accounting */
          nat44_session_update_counters (s, now,
@@ -603,15 +596,18 @@ nat44_ed_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip,
   u32 tx_fib_index = ip4_fib_table_get_index_for_sw_if_index (tx_sw_if_index);
 
   /* src NAT check */
-  make_ed_kv (&ip->src_address, &ip->dst_address, ip->protocol,
-             tx_fib_index, src_port, dst_port, ~0ULL, &kv);
-  if (!clib_bihash_search_16_8 (&tsm->out2in_ed, &kv, &value))
+  init_ed_k (&kv, ip->src_address, src_port, ip->dst_address, dst_port,
+            tx_fib_index, ip->protocol);
+  if (!clib_bihash_search_16_8 (&sm->out2in_ed, &kv, &value))
     {
-      s = pool_elt_at_index (tsm->sessions, value.value);
+      ASSERT (thread_index == ed_value_get_thread_index (&value));
+      s =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&value));
       if (nat44_is_ses_closed (s))
        {
          nat_free_session_data (sm, s, thread_index, 0);
-         nat44_ed_delete_session (sm, s, thread_index, 1);
+         nat_ed_session_delete (sm, s, thread_index, 1);
        }
       else
        s->flags |= SNAT_SESSION_FLAG_OUTPUT_FEATURE;
@@ -619,11 +615,14 @@ nat44_ed_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip,
     }
 
   /* dst NAT check */
-  make_ed_kv (&ip->dst_address, &ip->src_address, ip->protocol,
-             rx_fib_index, dst_port, src_port, ~0ULL, &kv);
+  init_ed_k (&kv, ip->dst_address, dst_port, ip->src_address, src_port,
+            rx_fib_index, ip->protocol);
   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv, &value))
     {
-      s = pool_elt_at_index (tsm->sessions, value.value);
+      ASSERT (thread_index == ed_value_get_thread_index (&value));
+      s =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&value));
       if (is_fwd_bypass_session (s))
        return 0;
 
@@ -644,25 +643,27 @@ nat44_ed_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip,
 #ifndef CLIB_MARCH_VARIANT
 u32
 icmp_match_in2out_ed (snat_main_t * sm, vlib_node_runtime_t * node,
-                     u32 thread_index, vlib_buffer_t * b, ip4_header_t * ip,
-                     u8 * p_proto, snat_session_key_t * p_value,
-                     u8 * p_dont_translate, void *d, void *e)
+                     u32 thread_index, vlib_buffer_t * b,
+                     ip4_header_t * ip, ip4_address_t * addr,
+                     u16 * port, u32 * fib_index, nat_protocol_t * proto,
+                     void *d, void *e, u8 * dont_translate)
 {
   u32 sw_if_index;
   u32 rx_fib_index;
-  snat_session_t *s = 0;
-  u8 dont_translate = 0;
   clib_bihash_kv_16_8_t kv, value;
   u32 next = ~0;
   int err;
+  snat_session_t *s = NULL;
   u16 l_port = 0, r_port = 0;  // initialize to workaround gcc warning
+  vlib_main_t *vm = vlib_get_main ();
   snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  *dont_translate = 0;
 
   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);
 
   err =
-    get_icmp_i2o_ed_key (b, ip, rx_fib_index, ~0ULL, p_proto, &l_port,
+    get_icmp_i2o_ed_key (b, ip, rx_fib_index, ~0, ~0, proto, &l_port,
                         &r_port, &kv);
   if (err != 0)
     {
@@ -680,18 +681,18 @@ icmp_match_in2out_ed (snat_main_t * sm, vlib_node_runtime_t * node,
               (sm, ip, l_port, r_port, thread_index,
                sw_if_index, vnet_buffer (b)->sw_if_index[VLIB_TX])))
            {
-             dont_translate = 1;
+             *dont_translate = 1;
              goto out;
            }
        }
       else
        {
          if (PREDICT_FALSE (nat44_ed_not_translate (sm, node, sw_if_index,
-                                                    ip, SNAT_PROTOCOL_ICMP,
+                                                    ip, NAT_PROTOCOL_ICMP,
                                                     rx_fib_index,
                                                     thread_index)))
            {
-             dont_translate = 1;
+             *dont_translate = 1;
              goto out;
            }
        }
@@ -708,14 +709,14 @@ icmp_match_in2out_ed (snat_main_t * sm, vlib_node_runtime_t * node,
       next =
        slow_path_ed (sm, b, ip->src_address, ip->dst_address, l_port, r_port,
                      ip->protocol, rx_fib_index, &s, node, next,
-                     thread_index, vlib_time_now (sm->vlib_main));
+                     thread_index, vlib_time_now (vm));
 
       if (PREDICT_FALSE (next == NAT_NEXT_DROP))
        goto out;
 
       if (!s)
        {
-         dont_translate = 1;
+         *dont_translate = 1;
          goto out;
        }
     }
@@ -734,14 +735,22 @@ icmp_match_in2out_ed (snat_main_t * sm, vlib_node_runtime_t * node,
          goto out;
        }
 
-      s = pool_elt_at_index (tsm->sessions, value.value);
+      ASSERT (thread_index == ed_value_get_thread_index (&value));
+      s =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&value));
     }
 out:
   if (s)
-    *p_value = s->out2in;
-  *p_dont_translate = dont_translate;
+    {
+      *addr = s->out2in.addr;
+      *port = s->out2in.port;
+      *fib_index = s->out2in.fib_index;
+    }
   if (d)
-    *(snat_session_t **) d = s;
+    {
+      *(snat_session_t **) d = s;
+    }
   return next;
 }
 #endif
@@ -765,15 +774,6 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
   u32 outside_fib_index = sm->outside_fib_index;
   int i;
   u8 is_sm = 0;
-  nat_outside_fib_t *outside_fib;
-  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
-  fib_prefix_t pfx = {
-    .fp_proto = FIB_PROTOCOL_IP4,
-    .fp_len = 32,
-    .fp_addr = {
-               .ip4.as_u32 = ip->dst_address.as_u32,
-               },
-  };
 
   switch (vec_len (sm->outside_fibs))
     {
@@ -784,43 +784,36 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
       outside_fib_index = sm->outside_fibs[0].fib_index;
       break;
     default:
-      /* *INDENT-OFF* */
-      vec_foreach (outside_fib, sm->outside_fibs)
-        {
-         fei = fib_table_lookup (outside_fib->fib_index, &pfx);
-         if (FIB_NODE_INDEX_INVALID != fei)
-           {
-             if (fib_entry_get_resolving_interface (fei) != ~0)
-               {
-                 outside_fib_index = outside_fib->fib_index;
-                 break;
-               }
-           }
-        }
-      /* *INDENT-ON* */
+      outside_fib_index = nat_outside_fib_index_lookup (sm, ip->dst_address);
       break;
     }
   old_addr = ip->src_address.as_u32;
 
-  make_ed_kv (&ip->src_address, &ip->dst_address, ip->protocol,
-             rx_fib_index, 0, 0, ~0ULL, &s_kv);
+  init_ed_k (&s_kv, ip->src_address, 0, ip->dst_address, 0, rx_fib_index,
+            ip->protocol);
 
   if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &s_kv, &s_value))
     {
-      s = pool_elt_at_index (tsm->sessions, s_value.value);
+      ASSERT (thread_index == ed_value_get_thread_index (&s_value));
+      s =
+       pool_elt_at_index (tsm->sessions,
+                          ed_value_get_session_index (&s_value));
       new_addr = ip->src_address.as_u32 = s->out2in.addr.as_u32;
     }
   else
     {
-      if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
+      if (PREDICT_FALSE
+         (nat44_ed_maximum_sessions_exceeded
+          (sm, rx_fib_index, thread_index)))
        {
          b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
-         nat_ipfix_logging_max_sessions (thread_index, sm->max_translations);
+         nat_ipfix_logging_max_sessions (thread_index,
+                                         sm->max_translations_per_thread);
          nat_elog_notice ("maximum sessions exceeded");
          return 0;
        }
 
-      make_sm_kv (&kv, &ip->src_address, 0, rx_fib_index, 0);
+      init_nat_k (&kv, ip->src_address, 0, rx_fib_index, 0);
 
       /* Try to find static mapping first */
       if (!clib_bihash_search_8_8 (&sm->static_mapping_by_local, &kv, &value))
@@ -838,9 +831,8 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
              {
                new_addr = ip->src_address.as_u32 = s->out2in.addr.as_u32;
 
-               make_ed_kv (&s->out2in.addr, &ip->dst_address, ip->protocol,
-                           outside_fib_index, 0, 0, ~0ULL, &s_kv);
-               if (clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
+               init_ed_k(&s_kv, s->out2in.addr, 0, ip->dst_address, 0, outside_fib_index, ip->protocol);
+               if (clib_bihash_search_16_8 (&sm->out2in_ed, &s_kv, &s_value))
                  goto create_ses;
 
                break;
@@ -850,10 +842,9 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
 
          for (i = 0; i < vec_len (sm->addresses); i++)
            {
-             make_ed_kv (&sm->addresses[i].addr, &ip->dst_address,
-                         ip->protocol, outside_fib_index, 0, 0, ~0ULL,
-                         &s_kv);
-             if (clib_bihash_search_16_8 (&tsm->out2in_ed, &s_kv, &s_value))
+             init_ed_k (&s_kv, sm->addresses[i].addr, 0, ip->dst_address, 0,
+                        outside_fib_index, ip->protocol);
+             if (clib_bihash_search_16_8 (&sm->out2in_ed, &s_kv, &s_value))
                {
                  new_addr = ip->src_address.as_u32 =
                    sm->addresses[i].addr.as_u32;
@@ -864,10 +855,10 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
        }
 
     create_ses:
-      s = nat_ed_session_alloc (sm, thread_index, now);
+      s = nat_ed_session_alloc (sm, thread_index, now, ip->protocol);
       if (!s)
        {
-         b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_USER_SESS_EXCEEDED];
+         b->error = node->errors[NAT_IN2OUT_ED_ERROR_MAX_SESSIONS_EXCEEDED];
          nat_elog_warn ("create NAT session failed");
          return 0;
        }
@@ -884,15 +875,18 @@ nat44_ed_in2out_unknown_proto (snat_main_t * sm,
        s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
 
       /* Add to lookup tables */
-      make_ed_kv (&s->in2out.addr, &ip->dst_address, ip->protocol,
-                 rx_fib_index, 0, 0, s - tsm->sessions, &s_kv);
+      init_ed_kv (&s_kv, s->in2out.addr, 0, ip->dst_address, 0, rx_fib_index,
+                 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");
 
-      make_ed_kv (&s->out2in.addr, &ip->dst_address, ip->protocol,
-                 outside_fib_index, 0, 0, s - tsm->sessions, &s_kv);
-      if (clib_bihash_add_del_16_8 (&tsm->out2in_ed, &s_kv, 1))
+      init_ed_kv (&s_kv, s->out2in.addr, 0, ip->dst_address, 0,
+                 outside_fib_index, ip->protocol, thread_index,
+                 s - tsm->sessions);
+      if (clib_bihash_add_del_16_8 (&sm->out2in_ed, &s_kv, 1))
        nat_elog_notice ("out2in key add failed");
+
+      per_vrf_sessions_register_session (s, thread_index);
     }
 
   /* Update IP checksum */
@@ -922,203 +916,178 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t * vm,
                                          vlib_frame_t * frame,
                                          int is_output_feature)
 {
-  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, def_slow;
-
-  def_slow = is_output_feature ? NAT_NEXT_IN2OUT_ED_OUTPUT_SLOW_PATH :
-    NAT_NEXT_IN2OUT_ED_SLOW_PATH;
-
-  stats_node_index = sm->ed_in2out_node_index;
+  u32 def_slow = is_output_feature ? NAT_NEXT_IN2OUT_ED_OUTPUT_SLOW_PATH
+    : NAT_NEXT_IN2OUT_ED_SLOW_PATH;
 
   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, new_addr0, old_addr0,
+       iph_offset0 = 0;
+      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;
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+         p2 = *b;
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+         vlib_prefetch_buffer_header (p2, LOAD);
+
+         CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, LOAD);
+       }
+
+      if (is_output_feature)
        {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0, sw_if_index0, rx_fib_index0, iph_offset0 = 0, proto0,
-           new_addr0, old_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);
+         iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
+       }
 
-         if (is_output_feature)
-           {
-             vnet_feature_next (&vnet_buffer2 (b0)->nat.arc_next, b0);
-             iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
-           }
+      next[0] = vnet_buffer2 (b0)->nat.arc_next;
 
-         next0 = vnet_buffer2 (b0)->nat.arc_next;
+      ip0 =
+       (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) + iph_offset0);
 
-         ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
-                                 iph_offset0);
+      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);
 
-         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;
+       }
 
-         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;
-           }
+      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_snat_proto (ip0->protocol);
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       {
+         next[0] = def_slow;
+         goto trace0;
+       }
 
-         if (PREDICT_FALSE (proto0 == ~0))
-           {
-             next0 = def_slow;
-             goto trace0;
-           }
+      if (is_output_feature)
+       {
+         if (PREDICT_FALSE
+             (nat_not_translate_output_feature_fwd
+              (sm, ip0, thread_index, now, vm, b0)))
+           goto trace0;
+       }
 
-         if (is_output_feature)
-           {
-             if (PREDICT_FALSE (nat_not_translate_output_feature_fwd
-                                (sm, ip0, thread_index, now, vm, b0)))
-               goto trace0;
-           }
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next[0] = def_slow;
+         goto trace0;
+       }
 
-         if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
-           {
-             next0 = def_slow;
-             goto trace0;
-           }
+      init_ed_k (&kv0, ip0->src_address,
+                vnet_buffer (b0)->ip.reass.l4_src_port, ip0->dst_address,
+                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+                ip0->protocol);
 
-         make_ed_kv (&ip0->src_address, &ip0->dst_address,
-                     ip0->protocol, rx_fib_index0,
-                     vnet_buffer (b0)->ip.reass.l4_src_port,
-                     vnet_buffer (b0)->ip.reass.l4_dst_port, ~0ULL, &kv0);
+      // lookup for session
+      if (clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
+       {
+         // session does not exist go slow path
+         next[0] = def_slow;
+         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 (&tsm->in2out_ed, &kv0, &value0))
-           {
-             // session does not exist go slow path
-             next0 = def_slow;
-             goto trace0;
-           }
-         s0 = pool_elt_at_index (tsm->sessions, value0.value);
+      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_close_timestamp)
+      if (s0->tcp_closed_timestamp)
+       {
+         if (now >= s0->tcp_closed_timestamp)
            {
-             if (now >= s0->tcp_close_timestamp)
-               {
-                 // session is closed, go slow path
-                 next0 = def_slow;
-               }
-             else
-               {
-                 // session in transitory timeout, drop
-                 b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TCP_CLOSED];
-                 next0 = NAT_NEXT_DROP;
-               }
-             goto trace0;
+             // session is closed, go slow path, freed in slow path
+             next[0] = def_slow;
            }
-
-         // 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
            {
-             nat_free_session_data (sm, s0, thread_index, 0);
-             nat44_ed_delete_session (sm, s0, thread_index, 1);
-             // session is closed, go slow path
-             next0 = def_slow;
-             goto trace0;
+             // session in transitory timeout, drop
+             b0->error = node->errors[NAT_IN2OUT_ED_ERROR_TCP_CLOSED];
+             next[0] = NAT_NEXT_DROP;
            }
+         goto trace0;
+       }
 
-         b0->flags |= VNET_BUFFER_F_IS_NATED;
+      // 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)
+       {
+         nat_free_session_data (sm, s0, thread_index, 0);
+         nat_ed_session_delete (sm, s0, thread_index, 1);
+         // session is closed, go slow path
+         next[0] = def_slow;
+         goto trace0;
+       }
 
-         if (!is_output_feature)
-           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
+      b0->flags |= VNET_BUFFER_F_IS_NATED;
 
-         old_addr0 = ip0->src_address.as_u32;
-         new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                src_address);
-         if (PREDICT_FALSE (is_twice_nat_session (s0)))
-           sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                  s0->ext_host_addr.as_u32, ip4_header_t,
-                                  dst_address);
-         ip0->checksum = ip_csum_fold (sum0);
+      if (!is_output_feature)
+       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
 
-         old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
+      old_addr0 = ip0->src_address.as_u32;
+      new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
+      sum0 = ip0->checksum;
+      sum0 =
+       ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                       src_address);
+      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+       sum0 =
+         ip_csum_update (sum0, ip0->dst_address.as_u32,
+                         s0->ext_host_addr.as_u32, ip4_header_t,
+                         dst_address);
+      ip0->checksum = ip_csum_fold (sum0);
 
-         if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
-           {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 new_port0 = udp0->src_port = s0->out2in.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 (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     sum0 =
-                       ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                       s0->ext_host_addr.as_u32,
-                                       ip4_header_t, dst_address);
-                     sum0 =
-                       ip_csum_update (sum0,
-                                       vnet_buffer (b0)->ip.
-                                       reass.l4_dst_port, s0->ext_host_port,
-                                       ip4_header_t, length);
-                     tcp0->dst_port = s0->ext_host_port;
-                     ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
-                   }
-                 mss_clamping (sm, tcp0, &sum0);
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
-             if (nat44_set_tcp_session_state_i2o
-                 (sm, now, s0, b0, 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_src_port;
+
+      if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
            {
              new_port0 = udp0->src_port = s0->out2in.port;
-             sum0 = udp0->checksum;
+             sum0 = tcp0->checksum;
              sum0 =
                ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
                                dst_address);
@@ -1127,79 +1096,103 @@ nat44_ed_in2out_fast_path_node_fn_inline (vlib_main_t * vm,
                                length);
              if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                        s0->ext_host_addr.as_u32,
-                                        ip4_header_t, dst_address);
+                 sum0 =
+                   ip_csum_update (sum0, ip0->dst_address.as_u32,
+                                   s0->ext_host_addr.as_u32, ip4_header_t,
+                                   dst_address);
                  sum0 =
                    ip_csum_update (sum0,
                                    vnet_buffer (b0)->ip.reass.l4_dst_port,
                                    s0->ext_host_port, ip4_header_t, length);
-                 udp0->dst_port = s0->ext_host_port;
+                 tcp0->dst_port = s0->ext_host_port;
                  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
                }
-             udp0->checksum = ip_csum_fold (sum0);
-             udp_packets++;
+             mss_clamping (sm->mss_clamping, tcp0, &sum0);
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.fastpath.in2out_ed.tcp,
+                                        thread_index, sw_if_index0, 1);
+         nat44_set_tcp_session_state_i2o (sm, now, s0, b0, thread_index);
+       }
+      else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
+              && udp0->checksum)
+       {
+         new_port0 = udp0->src_port = s0->out2in.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->dst_address.as_u32,
+                               s0->ext_host_addr.as_u32, ip4_header_t,
+                               dst_address);
+             sum0 =
+               ip_csum_update (sum0, vnet_buffer (b0)->ip.reass.l4_dst_port,
+                               s0->ext_host_port, ip4_header_t, length);
+             udp0->dst_port = s0->ext_host_port;
+             ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+           }
+         udp0->checksum = ip_csum_fold (sum0);
+         vlib_increment_simple_counter (&sm->counters.fastpath.in2out_ed.udp,
+                                        thread_index, sw_if_index0, 1);
+       }
+      else
+       {
+         if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
+           {
+             new_port0 = udp0->src_port = s0->out2in.port;
+             if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 new_port0 = udp0->src_port = s0->out2in.port;
-                 if (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     udp0->dst_port = s0->ext_host_port;
-                     ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
-                   }
-                 udp_packets++;
+                 udp0->dst_port = s0->ext_host_port;
+                 ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
                }
+             vlib_increment_simple_counter (&sm->counters.fastpath.
+                                            in2out_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)))
-           {
-             nat_in2out_ed_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)))
+       {
+         nat_in2out_ed_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.
+                                        in2out_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_IN2OUT_ED_ERROR_IN2OUT_PACKETS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_TCP_PACKETS, tcp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_UDP_PACKETS, udp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_ICMP_PACKETS,
-                              icmp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_OTHER_PACKETS,
-                              other_packets);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
   return frame->n_vectors;
 }
 
@@ -1209,305 +1202,283 @@ nat44_ed_in2out_slow_path_node_fn_inline (vlib_main_t * vm,
                                          vlib_frame_t * frame,
                                          int is_output_feature)
 {
-  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;
-
-  stats_node_index = sm->ed_in2out_slowpath_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, new_addr0, old_addr0,
+       iph_offset0 = 0;
+      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;
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      b0 = *b;
 
-      while (n_left_from > 0 && n_left_to_next > 0)
-       {
-         u32 bi0;
-         vlib_buffer_t *b0;
-         u32 next0, sw_if_index0, rx_fib_index0, iph_offset0 = 0, proto0,
-           new_addr0, old_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;
-
-         /* 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);
+      if (is_output_feature)
+       iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
 
-         if (is_output_feature)
-           iph_offset0 = vnet_buffer (b0)->ip.reass.save_rewrite_length;
+      next[0] = vnet_buffer2 (b0)->nat.arc_next;
 
-         next0 = vnet_buffer2 (b0)->nat.arc_next;
+      ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
+                             iph_offset0);
 
-         ip0 = (ip4_header_t *) ((u8 *) vlib_buffer_get_current (b0) +
-                                 iph_offset0);
+      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);
 
-         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;
+       }
 
-         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;
-           }
+      udp0 = ip4_next_header (ip0);
+      tcp0 = (tcp_header_t *) udp0;
+      icmp0 = (icmp46_header_t *) udp0;
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-         proto0 = ip_proto_to_snat_proto (ip0->protocol);
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       {
+         s0 = nat44_ed_in2out_unknown_proto (sm, b0, ip0,
+                                             rx_fib_index0,
+                                             thread_index, now, vm, node);
+         if (!s0)
+           next[0] = NAT_NEXT_DROP;
 
-         if (PREDICT_FALSE (proto0 == ~0))
-           {
-             s0 = nat44_ed_in2out_unknown_proto (sm, b0, ip0,
-                                                 rx_fib_index0,
-                                                 thread_index, now,
-                                                 vm, node);
-             if (!s0)
-               next0 = NAT_NEXT_DROP;
-
-             other_packets++;
-             goto trace0;
-           }
+         vlib_increment_simple_counter (&sm->counters.slowpath.
+                                        in2out_ed.other, thread_index,
+                                        sw_if_index0, 1);
+         goto trace0;
+       }
 
-         if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_ICMP))
+       {
+         next[0] =
+           icmp_in2out_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.
+                                        in2out_ed.icmp, thread_index,
+                                        sw_if_index0, 1);
+         goto trace0;
+       }
+
+      init_ed_k (&kv0, ip0->src_address,
+                vnet_buffer (b0)->ip.reass.l4_src_port, ip0->dst_address,
+                vnet_buffer (b0)->ip.reass.l4_dst_port, rx_fib_index0,
+                ip0->protocol);
+      if (!clib_bihash_search_16_8 (&tsm->in2out_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_in2out_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;
            }
+       }
 
-         // move down
-         make_ed_kv (&ip0->src_address, &ip0->dst_address,
-                     ip0->protocol, rx_fib_index0,
-                     vnet_buffer (b0)->ip.reass.l4_src_port,
-                     vnet_buffer (b0)->ip.reass.l4_dst_port, ~0ULL, &kv0);
-
-         if (!clib_bihash_search_16_8 (&tsm->in2out_ed, &kv0, &value0))
+      if (!s0)
+       {
+         if (is_output_feature)
            {
-             s0 = pool_elt_at_index (tsm->sessions, value0.value);
+             if (PREDICT_FALSE
+                 (nat44_ed_not_translate_output_feature
+                  (sm, ip0, vnet_buffer (b0)->ip.reass.l4_src_port,
+                   vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
+                   sw_if_index0, vnet_buffer (b0)->sw_if_index[VLIB_TX])))
+               goto trace0;
 
-             if (s0->tcp_close_timestamp && now >= s0->tcp_close_timestamp)
-               {
-                 nat_free_session_data (sm, s0, thread_index, 0);
-                 nat44_ed_delete_session (sm, s0, thread_index, 1);
-                 s0 = NULL;
-               }
+             /*
+              * 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_server))
+                  && ip0->dst_address.as_u32 == 0xffffffff))
+               goto trace0;
            }
-
-         if (!s0)
+         else
            {
-             if (is_output_feature)
-               {
-                 if (PREDICT_FALSE
-                     (nat44_ed_not_translate_output_feature
-                      (sm, ip0, vnet_buffer (b0)->ip.reass.l4_src_port,
-                       vnet_buffer (b0)->ip.reass.l4_dst_port, thread_index,
-                       sw_if_index0,
-                       vnet_buffer (b0)->sw_if_index[VLIB_TX])))
-                   goto trace0;
-
-                 /*
-                  * 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 == SNAT_PROTOCOL_UDP
-                      && (vnet_buffer (b0)->ip.reass.l4_dst_port ==
-                          clib_host_to_net_u16 (UDP_DST_PORT_dhcp_to_server))
-                      && ip0->dst_address.as_u32 == 0xffffffff))
-                   goto trace0;
-               }
-             else
-               {
-                 if (PREDICT_FALSE
-                     (nat44_ed_not_translate
-                      (sm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
-                       thread_index)))
-                   goto trace0;
-               }
+             if (PREDICT_FALSE
+                 (nat44_ed_not_translate
+                  (sm, node, sw_if_index0, ip0, proto0, rx_fib_index0,
+                   thread_index)))
+               goto trace0;
+           }
 
-             next0 =
-               slow_path_ed (sm, b0, ip0->src_address, ip0->dst_address,
-                             vnet_buffer (b0)->ip.reass.l4_src_port,
-                             vnet_buffer (b0)->ip.reass.l4_dst_port,
-                             ip0->protocol, rx_fib_index0, &s0, node, next0,
-                             thread_index, now);
+         next[0] =
+           slow_path_ed (sm, b0, ip0->src_address, ip0->dst_address,
+                         vnet_buffer (b0)->ip.reass.l4_src_port,
+                         vnet_buffer (b0)->ip.reass.l4_dst_port,
+                         ip0->protocol, rx_fib_index0, &s0, node, next[0],
+                         thread_index, now);
 
-             if (PREDICT_FALSE (next0 == NAT_NEXT_DROP))
-               goto trace0;
+         if (PREDICT_FALSE (next[0] == NAT_NEXT_DROP))
+           goto trace0;
 
-             if (PREDICT_FALSE (!s0))
-               goto trace0;
+         if (PREDICT_FALSE (!s0))
+           goto trace0;
 
-           }
+       }
 
-         b0->flags |= VNET_BUFFER_F_IS_NATED;
+      b0->flags |= VNET_BUFFER_F_IS_NATED;
 
-         if (!is_output_feature)
-           vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
+      if (!is_output_feature)
+       vnet_buffer (b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
 
-         old_addr0 = ip0->src_address.as_u32;
-         new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
-         sum0 = ip0->checksum;
-         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                                src_address);
-         if (PREDICT_FALSE (is_twice_nat_session (s0)))
-           sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                  s0->ext_host_addr.as_u32, ip4_header_t,
-                                  dst_address);
-         ip0->checksum = ip_csum_fold (sum0);
+      old_addr0 = ip0->src_address.as_u32;
+      new_addr0 = ip0->src_address.as_u32 = s0->out2in.addr.as_u32;
+      sum0 = ip0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                            src_address);
+      if (PREDICT_FALSE (is_twice_nat_session (s0)))
+       sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+                              s0->ext_host_addr.as_u32, ip4_header_t,
+                              dst_address);
+      ip0->checksum = ip_csum_fold (sum0);
 
-         old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
+      old_port0 = vnet_buffer (b0)->ip.reass.l4_src_port;
 
-         if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
-           {
-             if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
-               {
-                 new_port0 = udp0->src_port = s0->out2in.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 (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     sum0 =
-                       ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                       s0->ext_host_addr.as_u32,
-                                       ip4_header_t, dst_address);
-                     sum0 =
-                       ip_csum_update (sum0,
-                                       vnet_buffer (b0)->ip.
-                                       reass.l4_dst_port, s0->ext_host_port,
-                                       ip4_header_t, length);
-                     tcp0->dst_port = s0->ext_host_port;
-                     ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
-                   }
-                 mss_clamping (sm, tcp0, &sum0);
-                 tcp0->checksum = ip_csum_fold (sum0);
-               }
-             tcp_packets++;
-             if (nat44_set_tcp_session_state_i2o
-                 (sm, now, s0, b0, 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->src_port = s0->out2in.port;
-             sum0 = udp0->checksum;
+             sum0 = tcp0->checksum;
              sum0 =
-               ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                               dst_address);
+               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);
+               ip_csum_update (sum0, old_port0, new_port0,
+                               ip4_header_t, length);
              if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 sum0 = ip_csum_update (sum0, ip0->dst_address.as_u32,
-                                        s0->ext_host_addr.as_u32,
-                                        ip4_header_t, dst_address);
+                 sum0 =
+                   ip_csum_update (sum0, ip0->dst_address.as_u32,
+                                   s0->ext_host_addr.as_u32,
+                                   ip4_header_t, dst_address);
                  sum0 =
                    ip_csum_update (sum0,
                                    vnet_buffer (b0)->ip.reass.l4_dst_port,
                                    s0->ext_host_port, ip4_header_t, length);
-                 udp0->dst_port = s0->ext_host_port;
+                 tcp0->dst_port = s0->ext_host_port;
                  ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
                }
-             udp0->checksum = ip_csum_fold (sum0);
-             udp_packets++;
+             mss_clamping (sm->mss_clamping, tcp0, &sum0);
+             tcp0->checksum = ip_csum_fold (sum0);
            }
-         else
+         vlib_increment_simple_counter (&sm->counters.slowpath.in2out_ed.tcp,
+                                        thread_index, sw_if_index0, 1);
+         nat44_set_tcp_session_state_i2o (sm, now, s0, b0, thread_index);
+       }
+      else if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment
+              && udp0->checksum)
+       {
+         new_port0 = udp0->src_port = s0->out2in.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 = ip_csum_update (sum0, ip0->dst_address.as_u32,
+                                    s0->ext_host_addr.as_u32,
+                                    ip4_header_t, dst_address);
+             sum0 =
+               ip_csum_update (sum0,
+                               vnet_buffer (b0)->ip.reass.l4_dst_port,
+                               s0->ext_host_port, ip4_header_t, length);
+             udp0->dst_port = s0->ext_host_port;
+             ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
+           }
+         udp0->checksum = ip_csum_fold (sum0);
+         vlib_increment_simple_counter (&sm->counters.slowpath.in2out_ed.udp,
+                                        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)
+             new_port0 = udp0->src_port = s0->out2in.port;
+             if (PREDICT_FALSE (is_twice_nat_session (s0)))
                {
-                 new_port0 = udp0->src_port = s0->out2in.port;
-                 if (PREDICT_FALSE (is_twice_nat_session (s0)))
-                   {
-                     udp0->dst_port = s0->ext_host_port;
-                     ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
-                   }
-                 udp_packets++;
+                 udp0->dst_port = s0->ext_host_port;
+                 ip0->dst_address.as_u32 = s0->ext_host_addr.as_u32;
                }
+             vlib_increment_simple_counter (&sm->counters.slowpath.
+                                            in2out_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);
-
-       trace0:
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             nat_in2out_ed_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;
-           }
+      /* 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);
 
-         pkts_processed += next0 == vnet_buffer2 (b0)->nat.arc_next;
+    trace0:
+      if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+                        && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+       {
+         nat_in2out_ed_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;
+       }
 
-         /* 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.
+                                        in2out_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_IN2OUT_ED_ERROR_IN2OUT_PACKETS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_TCP_PACKETS, tcp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_UDP_PACKETS, udp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_ICMP_PACKETS,
-                              icmp_packets);
-  vlib_node_increment_counter (vm, stats_node_index,
-                              NAT_IN2OUT_ED_ERROR_OTHER_PACKETS,
-                              other_packets);
+  vlib_buffer_enqueue_to_next (vm, node, from, (u16 *) nexts,
+                              frame->n_vectors);
+
   return frame->n_vectors;
 }
 
@@ -1598,7 +1569,8 @@ format_nat_pre_trace (u8 * s, va_list * args)
   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
   nat_pre_trace_t *t = va_arg (*args, nat_pre_trace_t *);
-  return format (s, "in2out next_index %d", t->next_index);
+  return format (s, "in2out next_index %d arc_next_index %d", t->next_index,
+                t->arc_next_index);
 }
 
 VLIB_NODE_FN (nat_pre_in2out_node)
@@ -1608,6 +1580,13 @@ VLIB_NODE_FN (nat_pre_in2out_node)
                                 NAT_NEXT_IN2OUT_ED_FAST_PATH);
 }
 
+VLIB_NODE_FN (nat_pre_in2out_output_node)
+  (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  return nat_pre_node_fn_inline (vm, node, frame,
+                                NAT_NEXT_IN2OUT_ED_OUTPUT_FAST_PATH);
+}
+
 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (nat_pre_in2out_node) = {
   .name = "nat-pre-in2out",
@@ -1617,6 +1596,15 @@ VLIB_REGISTER_NODE (nat_pre_in2out_node) = {
   .type = VLIB_NODE_TYPE_INTERNAL,
   .n_errors = 0,
 };
+
+VLIB_REGISTER_NODE (nat_pre_in2out_output_node) = {
+  .name = "nat-pre-in2out-output",
+  .vector_size = sizeof (u32),
+  .sibling_of = "nat-default",
+  .format_trace = format_nat_pre_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = 0,
+};
 /* *INDENT-ON* */
 
 /*