nat: cleanup & reorganization
[vpp.git] / src / plugins / nat / out2in.c
old mode 100755 (executable)
new mode 100644 (file)
index 8c6cb48..c8c4542
 
 #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/nat_reass.h>
+#include <nat/lib/ipfix_logging.h>
 #include <nat/nat_inlines.h>
-#include <nat/nat_syslog.h>
+#include <nat/nat44/inlines.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
 {
@@ -107,7 +96,6 @@ typedef enum
   SNAT_OUT2IN_NEXT_DROP,
   SNAT_OUT2IN_NEXT_LOOKUP,
   SNAT_OUT2IN_NEXT_ICMP_ERROR,
-  SNAT_OUT2IN_NEXT_REASS,
   SNAT_OUT2IN_N_NEXT,
 } snat_out2in_next_t;
 
@@ -127,30 +115,30 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
   sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
   if (ctx->now >= sess_timeout_time)
     {
-      s_kv.key = s->in2out.as_u64;
+      init_nat_i2o_k (&s_kv, s);
       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->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_apmdel (s->user_index, s->in2out.fib_index,
                               &s->in2out.addr, s->in2out.port,
-                              &s->out2in.addr, s->out2in.port,
-                              s->in2out.protocol);
+                              &s->out2in.addr, s->out2in.port, s->nat_proto);
 
       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 (!snat_is_session_static (s))
        snat_free_outside_address_and_port (sm->addresses, ctx->thread_index,
-                                           &s->out2in);
+                                           &s->out2in.addr, s->out2in.port,
+                                           s->nat_proto);
 
       nat44_delete_session (sm, s, ctx->thread_index);
       return 1;
@@ -177,8 +165,13 @@ nat44_o2i_is_idle_session_cb (clib_bihash_kv_8_8_t * kv, void *arg)
 static inline snat_session_t *
 create_session_for_static_mapping (snat_main_t * sm,
                                   vlib_buffer_t * b0,
-                                  snat_session_key_t in2out,
-                                  snat_session_key_t out2in,
+                                  ip4_address_t i2o_addr,
+                                  u16 i2o_port,
+                                  u32 i2o_fib_index,
+                                  ip4_address_t o2i_addr,
+                                  u16 o2i_port,
+                                  u32 o2i_fib_index,
+                                  nat_protocol_t proto,
                                   vlib_node_runtime_t * node,
                                   u32 thread_index, f64 now)
 {
@@ -189,7 +182,7 @@ create_session_for_static_mapping (snat_main_t * sm,
   udp_header_t *udp0;
   nat44_is_idle_session_ctx_t ctx0;
 
-  if (PREDICT_FALSE (maximum_sessions_exceeded (sm, thread_index)))
+  if (PREDICT_FALSE (nat44_maximum_sessions_exceeded (sm, thread_index)))
     {
       b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_SESSIONS_EXCEEDED];
       nat_elog_notice ("maximum sessions exceeded");
@@ -199,11 +192,10 @@ create_session_for_static_mapping (snat_main_t * sm,
   ip0 = vlib_buffer_get_current (b0);
   udp0 = ip4_next_header (ip0);
 
-  u =
-    nat_user_get_or_create (sm, &in2out.addr, in2out.fib_index, thread_index);
+  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;
     }
 
@@ -219,55 +211,55 @@ create_session_for_static_mapping (snat_main_t * sm,
   s->ext_host_addr.as_u32 = ip0->src_address.as_u32;
   s->ext_host_port = udp0->src_port;
   user_session_increment (sm, u, 1 /* static */ );
-  s->in2out = in2out;
-  s->out2in = out2in;
-  s->in2out.protocol = out2in.protocol;
+  s->in2out.addr = i2o_addr;
+  s->in2out.port = i2o_port;
+  s->in2out.fib_index = i2o_fib_index;
+  s->out2in.addr = o2i_addr;
+  s->out2in.port = o2i_port;
+  s->out2in.fib_index = o2i_fib_index;
+  s->nat_proto = proto;
 
   /* Add to translation hashes */
   ctx0.now = now;
   ctx0.thread_index = thread_index;
-  kv0.key = s->in2out.as_u64;
-  kv0.value = s - sm->per_thread_data[thread_index].sessions;
+  init_nat_i2o_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
   if (clib_bihash_add_or_overwrite_stale_8_8
       (&sm->per_thread_data[thread_index].in2out, &kv0,
        nat44_i2o_is_idle_session_cb, &ctx0))
     nat_elog_notice ("in2out key add failed");
 
-  kv0.key = s->out2in.as_u64;
-
+  init_nat_o2i_kv (&kv0, s, s - sm->per_thread_data[thread_index].sessions);
   if (clib_bihash_add_or_overwrite_stale_8_8
       (&sm->per_thread_data[thread_index].out2in, &kv0,
        nat44_o2i_is_idle_session_cb, &ctx0))
     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->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_apmadd (s->user_index, s->in2out.fib_index,
                           &s->in2out.addr, s->in2out.port, &s->out2in.addr,
-                          s->out2in.port, s->in2out.protocol);
+                          s->out2in.port, s->nat_proto);
 
   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);
 
   return s;
 }
 
 #ifndef CLIB_MARCH_VARIANT
-static_always_inline
-  snat_out2in_error_t icmp_get_key (ip4_header_t * ip0,
-                                   snat_session_key_t * p_key0)
+static_always_inline snat_out2in_error_t
+icmp_get_key (vlib_buffer_t * b, ip4_header_t * ip0,
+             ip4_address_t * addr, u16 * port, nat_protocol_t * nat_proto)
 {
   icmp46_header_t *icmp0;
-  snat_session_key_t key0;
   icmp_echo_header_t *echo0, *inner_echo0 = 0;
   ip4_header_t *inner_ip0;
   void *l4_header = 0;
@@ -276,34 +268,34 @@ static_always_inline
   icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 
-  if (!icmp_is_error_message (icmp0))
+  if (!icmp_type_is_error_message
+      (vnet_buffer (b)->ip.reass.icmp_type_or_tcp_flags))
     {
-      key0.protocol = SNAT_PROTOCOL_ICMP;
-      key0.addr = ip0->dst_address;
-      key0.port = echo0->identifier;
+      *nat_proto = NAT_PROTOCOL_ICMP;
+      *addr = ip0->dst_address;
+      *port = vnet_buffer (b)->ip.reass.l4_src_port;
     }
   else
     {
       inner_ip0 = (ip4_header_t *) (echo0 + 1);
       l4_header = ip4_next_header (inner_ip0);
-      key0.protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
-      key0.addr = inner_ip0->src_address;
-      switch (key0.protocol)
+      *nat_proto = ip_proto_to_nat_proto (inner_ip0->protocol);
+      *addr = inner_ip0->src_address;
+      switch (*nat_proto)
        {
-       case SNAT_PROTOCOL_ICMP:
+       case NAT_PROTOCOL_ICMP:
          inner_icmp0 = (icmp46_header_t *) l4_header;
          inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
-         key0.port = inner_echo0->identifier;
+         *port = inner_echo0->identifier;
          break;
-       case SNAT_PROTOCOL_UDP:
-       case SNAT_PROTOCOL_TCP:
-         key0.port = ((tcp_udp_header_t *) l4_header)->src_port;
+       case NAT_PROTOCOL_UDP:
+       case NAT_PROTOCOL_TCP:
+         *port = ((tcp_udp_header_t *) l4_header)->src_port;
          break;
        default:
          return SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL;
        }
     }
-  *p_key0 = key0;
   return -1;                   /* success */
 }
 
@@ -315,6 +307,7 @@ static_always_inline
  * @param[in,out] node           NAT node runtime
  * @param[in] thread_index       thread index
  * @param[in,out] b0             buffer containing packet to be translated
+ * @param[in,out] ip0            ip header
  * @param[out] p_proto           protocol used for matching
  * @param[out] p_value           address and port after NAT translation
  * @param[out] p_dont_translate  if packet should not be translated
@@ -324,47 +317,48 @@ static_always_inline
 u32
 icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
                        u32 thread_index, vlib_buffer_t * b0,
-                       ip4_header_t * ip0, u8 * p_proto,
-                       snat_session_key_t * p_value,
-                       u8 * p_dont_translate, void *d, void *e)
+                       ip4_header_t * ip0, ip4_address_t * addr,
+                       u16 * port, u32 * fib_index,
+                       nat_protocol_t * proto, void *d, void *e,
+                       u8 * dont_translate)
 {
-  icmp46_header_t *icmp0;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
   u32 sw_if_index0;
-  u32 rx_fib_index0;
-  snat_session_key_t key0;
-  snat_session_key_t sm0;
   snat_session_t *s0 = 0;
-  u8 dont_translate = 0;
   clib_bihash_kv_8_8_t kv0, value0;
   u8 is_addr_only;
   u32 next0 = ~0;
   int err;
   u8 identity_nat;
+  vlib_main_t *vm = vlib_get_main ();
+  *dont_translate = 0;
 
-  icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
   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);
+  *fib_index = ip4_fib_table_get_index_for_sw_if_index (sw_if_index0);
 
-  key0.protocol = 0;
+  *proto = 0;
 
-  err = icmp_get_key (ip0, &key0);
+  err = icmp_get_key (b0, ip0, addr, port, proto);
   if (err != -1)
     {
       b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
       next0 = SNAT_OUT2IN_NEXT_DROP;
       goto out;
     }
-  key0.fib_index = rx_fib_index0;
 
-  kv0.key = key0.as_u64;
+  ip4_address_t mapping_addr;
+  u16 mapping_port;
+  u32 mapping_fib_index;
 
-  if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
-                             &value0))
+  init_nat_k (&kv0, *addr, *port, *fib_index, *proto);
+  if (clib_bihash_search_8_8 (&tsm->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, key0, &sm0, 1, &is_addr_only, 0, 0, 0, &identity_nat))
+         (sm, *addr, *port, *fib_index, *proto,
+          &mapping_addr, &mapping_port, &mapping_fib_index, 1, &is_addr_only,
+          0, 0, 0, &identity_nat, 0))
        {
          if (!sm->forwarding_enabled)
            {
@@ -372,7 +366,7 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
              if (PREDICT_FALSE (is_interface_addr (sm, node, sw_if_index0,
                                                    ip0->dst_address.as_u32)))
                {
-                 dont_translate = 1;
+                 *dont_translate = 1;
                  goto out;
                }
              b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
@@ -381,14 +375,16 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
            }
          else
            {
-             dont_translate = 1;
+             *dont_translate = 1;
              goto out;
            }
        }
 
-      if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
-                        (icmp0->type != ICMP4_echo_request
-                         || !is_addr_only)))
+      if (PREDICT_FALSE
+         (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
+          ICMP4_echo_reply
+          && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
+              ICMP4_echo_request || !is_addr_only)))
        {
          b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
          next0 = SNAT_OUT2IN_NEXT_DROP;
@@ -397,13 +393,15 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
 
       if (PREDICT_FALSE (identity_nat))
        {
-         dont_translate = 1;
+         *dont_translate = 1;
          goto out;
        }
       /* Create session initiated by host from external network */
-      s0 = create_session_for_static_mapping (sm, b0, sm0, key0,
-                                             node, thread_index,
-                                             vlib_time_now (sm->vlib_main));
+      s0 =
+       create_session_for_static_mapping (sm, b0, mapping_addr, mapping_port,
+                                          mapping_fib_index, *addr, *port,
+                                          *fib_index, *proto, node,
+                                          thread_index, vlib_time_now (vm));
 
       if (!s0)
        {
@@ -413,24 +411,29 @@ icmp_match_out2in_slow (snat_main_t * sm, vlib_node_runtime_t * node,
     }
   else
     {
-      if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
-                        icmp0->type != ICMP4_echo_request &&
-                        !icmp_is_error_message (icmp0)))
+      if (PREDICT_FALSE
+         (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
+          ICMP4_echo_reply
+          && vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
+          ICMP4_echo_request
+          && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
+                                          reass.icmp_type_or_tcp_flags)))
        {
          b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
          next0 = SNAT_OUT2IN_NEXT_DROP;
          goto out;
        }
 
-      s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-                             value0.value);
+      s0 = pool_elt_at_index (tsm->sessions, value0.value);
     }
 
 out:
-  *p_proto = key0.protocol;
   if (s0)
-    *p_value = s0->in2out;
-  *p_dont_translate = dont_translate;
+    {
+      *addr = s0->in2out.addr;
+      *port = s0->in2out.port;
+      *fib_index = s0->in2out.fib_index;
+    }
   if (d)
     *(snat_session_t **) d = s0;
   return next0;
@@ -445,6 +448,7 @@ out:
  * @param[in,out] node           NAT node runtime
  * @param[in] thread_index       thread index
  * @param[in,out] b0             buffer containing packet to be translated
+ * @param[in,out] ip0            ip header
  * @param[out] p_proto           protocol used for matching
  * @param[out] p_value           address and port after NAT translation
  * @param[out] p_dont_translate  if packet should not be translated
@@ -454,40 +458,38 @@ out:
 u32
 icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
                        u32 thread_index, vlib_buffer_t * b0,
-                       ip4_header_t * ip0, u8 * p_proto,
-                       snat_session_key_t * p_value,
-                       u8 * p_dont_translate, void *d, void *e)
+                       ip4_header_t * ip0, ip4_address_t * mapping_addr,
+                       u16 * mapping_port, u32 * mapping_fib_index,
+                       nat_protocol_t * proto, void *d, void *e,
+                       u8 * dont_translate)
 {
-  icmp46_header_t *icmp0;
   u32 sw_if_index0;
   u32 rx_fib_index0;
-  snat_session_key_t key0;
-  snat_session_key_t sm0;
-  u8 dont_translate = 0;
   u8 is_addr_only;
   u32 next0 = ~0;
   int err;
+  ip4_address_t addr;
+  u16 port;
+  *dont_translate = 0;
 
-  icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
   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);
 
-  err = icmp_get_key (ip0, &key0);
+  err = icmp_get_key (b0, ip0, &addr, &port, proto);
   if (err != -1)
     {
       b0->error = node->errors[err];
       next0 = SNAT_OUT2IN_NEXT_DROP;
-      goto out2;
+      goto out;
     }
-  key0.fib_index = rx_fib_index0;
-
   if (snat_static_mapping_match
-      (sm, key0, &sm0, 1, &is_addr_only, 0, 0, 0, 0))
+      (sm, addr, port, rx_fib_index0, *proto, mapping_addr, mapping_port,
+       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))
        {
-         dont_translate = 1;
+         *dont_translate = 1;
          goto out;
        }
       b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
@@ -495,9 +497,12 @@ icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
       goto out;
     }
 
-  if (PREDICT_FALSE (icmp0->type != ICMP4_echo_reply &&
-                    (icmp0->type != ICMP4_echo_request || !is_addr_only) &&
-                    !icmp_is_error_message (icmp0)))
+  if (PREDICT_FALSE
+      (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags != ICMP4_echo_reply
+       && (vnet_buffer (b0)->ip.reass.icmp_type_or_tcp_flags !=
+          ICMP4_echo_request || !is_addr_only)
+       && !icmp_type_is_error_message (vnet_buffer (b0)->ip.
+                                      reass.icmp_type_or_tcp_flags)))
     {
       b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
       next0 = SNAT_OUT2IN_NEXT_DROP;
@@ -505,10 +510,6 @@ icmp_match_out2in_fast (snat_main_t * sm, vlib_node_runtime_t * node,
     }
 
 out:
-  *p_value = sm0;
-out2:
-  *p_proto = key0.protocol;
-  *p_dont_translate = dont_translate;
   return next0;
 }
 #endif
@@ -524,8 +525,6 @@ icmp_out2in (snat_main_t * sm,
             vlib_node_runtime_t * node,
             u32 next0, u32 thread_index, void *d, void *e)
 {
-  snat_session_key_t sm0;
-  u8 protocol;
   icmp_echo_header_t *echo0, *inner_echo0 = 0;
   ip4_header_t *inner_ip0 = 0;
   void *l4_header = 0;
@@ -536,12 +535,17 @@ icmp_out2in (snat_main_t * sm,
   ip_csum_t sum0;
   u16 checksum0;
   u32 next0_tmp;
+  vlib_main_t *vm = vlib_get_main ();
+  ip4_address_t addr;
+  u16 port;
+  u32 fib_index;
+  nat_protocol_t proto;
 
   echo0 = (icmp_echo_header_t *) (icmp0 + 1);
 
   next0_tmp = sm->icmp_match_out2in_cb (sm, node, thread_index, b0, ip0,
-                                       &protocol, &sm0, &dont_translate, d,
-                                       e);
+                                       &addr, &port, &fib_index, &proto,
+                                       d, e, &dont_translate);
   if (next0_tmp != ~0)
     next0 = next0_tmp;
   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
@@ -549,11 +553,12 @@ icmp_out2in (snat_main_t * sm,
 
   if (PREDICT_TRUE (!ip4_is_fragment (ip0)))
     {
-      sum0 = ip_incremental_checksum_buffer (sm->vlib_main, b0, (u8 *) icmp0 -
-                                            (u8 *)
-                                            vlib_buffer_get_current (b0),
-                                            ntohs (ip0->length) -
-                                            ip4_header_bytes (ip0), 0);
+      sum0 =
+       ip_incremental_checksum_buffer (vm, b0,
+                                       (u8 *) icmp0 -
+                                       (u8 *) vlib_buffer_get_current (b0),
+                                       ntohs (ip0->length) -
+                                       ip4_header_bytes (ip0), 0);
       checksum0 = ~ip_csum_fold (sum0);
       if (checksum0 != 0 && checksum0 != 0xffff)
        {
@@ -563,80 +568,86 @@ icmp_out2in (snat_main_t * sm,
     }
 
   old_addr0 = ip0->dst_address.as_u32;
-  new_addr0 = ip0->dst_address.as_u32 = sm0.addr.as_u32;
-  vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
+  new_addr0 = ip0->dst_address.as_u32 = addr.as_u32;
+  vnet_buffer (b0)->sw_if_index[VLIB_TX] = 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 (icmp0->checksum == 0)
-    icmp0->checksum = 0xffff;
 
-  if (!icmp_is_error_message (icmp0))
+  if (!vnet_buffer (b0)->ip.reass.is_non_first_fragment)
     {
-      new_id0 = sm0.port;
-      if (PREDICT_FALSE (new_id0 != echo0->identifier))
-       {
-         old_id0 = echo0->identifier;
-         new_id0 = sm0.port;
-         echo0->identifier = new_id0;
+      if (icmp0->checksum == 0)
+       icmp0->checksum = 0xffff;
 
-         sum0 = icmp0->checksum;
-         sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
-                                identifier /* changed member */ );
-         icmp0->checksum = ip_csum_fold (sum0);
-       }
-    }
-  else
-    {
-      inner_ip0 = (ip4_header_t *) (echo0 + 1);
-      l4_header = ip4_next_header (inner_ip0);
-
-      if (!ip4_header_checksum_is_valid (inner_ip0))
+      if (!icmp_type_is_error_message (icmp0->type))
        {
-         next0 = SNAT_OUT2IN_NEXT_DROP;
-         goto out;
+         new_id0 = port;
+         if (PREDICT_FALSE (new_id0 != echo0->identifier))
+           {
+             old_id0 = echo0->identifier;
+             new_id0 = port;
+             echo0->identifier = new_id0;
+
+             sum0 = icmp0->checksum;
+             sum0 =
+               ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+                               identifier /* changed member */ );
+             icmp0->checksum = ip_csum_fold (sum0);
+           }
        }
-
-      old_addr0 = inner_ip0->src_address.as_u32;
-      inner_ip0->src_address = sm0.addr;
-      new_addr0 = inner_ip0->src_address.as_u32;
-
-      sum0 = icmp0->checksum;
-      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
-                            src_address /* changed member */ );
-      icmp0->checksum = ip_csum_fold (sum0);
-
-      switch (protocol)
+      else
        {
-       case SNAT_PROTOCOL_ICMP:
-         inner_icmp0 = (icmp46_header_t *) l4_header;
-         inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
+         inner_ip0 = (ip4_header_t *) (echo0 + 1);
+         l4_header = ip4_next_header (inner_ip0);
+
+         if (!ip4_header_checksum_is_valid (inner_ip0))
+           {
+             next0 = SNAT_OUT2IN_NEXT_DROP;
+             goto out;
+           }
 
-         old_id0 = inner_echo0->identifier;
-         new_id0 = sm0.port;
-         inner_echo0->identifier = new_id0;
+         old_addr0 = inner_ip0->src_address.as_u32;
+         inner_ip0->src_address = addr;
+         new_addr0 = inner_ip0->src_address.as_u32;
 
          sum0 = icmp0->checksum;
-         sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
-                                identifier);
+         sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                                src_address /* changed member */ );
          icmp0->checksum = ip_csum_fold (sum0);
-         break;
-       case SNAT_PROTOCOL_UDP:
-       case SNAT_PROTOCOL_TCP:
-         old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
-         new_id0 = sm0.port;
-         ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
 
-         sum0 = icmp0->checksum;
-         sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
-                                src_port);
-         icmp0->checksum = ip_csum_fold (sum0);
-         break;
-       default:
-         ASSERT (0);
+         switch (proto)
+           {
+           case NAT_PROTOCOL_ICMP:
+             inner_icmp0 = (icmp46_header_t *) l4_header;
+             inner_echo0 = (icmp_echo_header_t *) (inner_icmp0 + 1);
+
+             old_id0 = inner_echo0->identifier;
+             new_id0 = port;
+             inner_echo0->identifier = new_id0;
+
+             sum0 = icmp0->checksum;
+             sum0 =
+               ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+                               identifier);
+             icmp0->checksum = ip_csum_fold (sum0);
+             break;
+           case NAT_PROTOCOL_UDP:
+           case NAT_PROTOCOL_TCP:
+             old_id0 = ((tcp_udp_header_t *) l4_header)->src_port;
+             new_id0 = port;
+             ((tcp_udp_header_t *) l4_header)->src_port = new_id0;
+
+             sum0 = icmp0->checksum;
+             sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
+                                    src_port);
+             icmp0->checksum = ip_csum_fold (sum0);
+             break;
+           default:
+             ASSERT (0);
+           }
        }
     }
 
@@ -656,6 +667,8 @@ icmp_out2in_slow_path (snat_main_t * sm,
                       u32 next0, f64 now,
                       u32 thread_index, snat_session_t ** p_s0)
 {
+  vlib_main_t *vm = vlib_get_main ();
+
   next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
                       next0, thread_index, p_s0, 0);
   snat_session_t *s0 = *p_s0;
@@ -664,7 +677,7 @@ icmp_out2in_slow_path (snat_main_t * sm,
       /* 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);
     }
@@ -678,15 +691,10 @@ nat_out2in_sm_unknown_proto (snat_main_t * sm,
 {
   clib_bihash_kv_8_8_t kv, value;
   snat_static_mapping_t *m;
-  snat_session_key_t m_key;
   u32 old_addr, new_addr;
   ip_csum_t sum;
 
-  m_key.addr = ip->dst_address;
-  m_key.port = 0;
-  m_key.protocol = 0;
-  m_key.fib_index = 0;
-  kv.key = m_key.as_u64;
+  init_nat_k (&kv, ip->dst_address, 0, 0, 0);
   if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
     return 1;
 
@@ -706,199 +714,186 @@ 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;
-  u32 tcp_packets = 0, udp_packets = 0, icmp_packets = 0, other_packets =
-    0, fragments = 0;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
 
   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;
-         snat_session_key_t key0, key1, sm0, sm1;
-         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;
-
-         /* 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, STORE);
-           CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
-         }
-
-         /* 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_snat_proto (ip0->protocol);
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-         if (PREDICT_FALSE (proto0 == ~0))
+      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;
-           }
-
-         if (PREDICT_FALSE (ip4_is_fragment (ip0)))
-           {
-             next0 = SNAT_OUT2IN_NEXT_REASS;
-             fragments++;
-             goto trace0;
-           }
-
-         if (PREDICT_FALSE (proto0 == SNAT_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;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index0, 1);
 
-         key0.addr = ip0->dst_address;
-         key0.port = udp0->dst_port;
-         key0.protocol = proto0;
-         key0.fib_index = rx_fib_index0;
+         goto trace0;
+       }
 
-         kv0.key = key0.as_u64;
+      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;
+       }
 
-         if (clib_bihash_search_8_8
-             (&sm->per_thread_data[thread_index].out2in, &kv0, &value0))
+      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, key0, &sm0, 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 == SNAT_PROTOCOL_UDP
-                                    && (udp0->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, sm0, key0, 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 (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;
-
-         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 == SNAT_PROTOCOL_TCP))
+
+         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)
            {
-             old_port0 = tcp0->dst_port;
-             tcp0->dst_port = s0->in2out.port;
-             new_port0 = tcp0->dst_port;
+             next0 = SNAT_OUT2IN_NEXT_DROP;
+             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;
+
+      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)
+           {
+             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,
@@ -908,162 +903,181 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
                                     ip4_header_t /* cheat */ ,
                                     length /* changed member */ );
              tcp0->checksum = ip_csum_fold (sum0);
-             tcp_packets++;
            }
-         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)
            {
-             old_port0 = udp0->dst_port;
-             udp0->dst_port = s0->in2out.port;
-             udp0->checksum = 0;
-             udp_packets++;
+             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);
+               }
            }
+         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_snat_proto (ip1->protocol);
+      proto1 = ip_proto_to_nat_proto (ip1->protocol);
 
-         if (PREDICT_FALSE (proto1 == ~0))
+      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;
-           }
-
-         if (PREDICT_FALSE (ip4_is_fragment (ip1)))
-           {
-             next1 = SNAT_OUT2IN_NEXT_REASS;
-             fragments++;
-             goto trace1;
-           }
-
-         if (PREDICT_FALSE (proto1 == SNAT_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;
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index1, 1);
+         goto trace1;
+       }
 
-         key1.addr = ip1->dst_address;
-         key1.port = udp1->dst_port;
-         key1.protocol = proto1;
-         key1.fib_index = rx_fib_index1;
+      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;
+       }
 
-         kv1.key = key1.as_u64;
+      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, key1, &sm1, 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 == SNAT_PROTOCOL_UDP
-                                    && (udp1->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, sm1, key1, 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 == SNAT_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)
            {
-             old_port1 = tcp1->dst_port;
-             tcp1->dst_port = s1->in2out.port;
-             new_port1 = tcp1->dst_port;
+             next1 = SNAT_OUT2IN_NEXT_DROP;
+             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 (!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,
@@ -1074,199 +1088,215 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
                                     ip4_header_t /* cheat */ ,
                                     length /* changed member */ );
              tcp1->checksum = ip_csum_fold (sum1);
-             tcp_packets++;
            }
-         else
+         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 = udp1->dst_port;
-             udp1->dst_port = s1->in2out.port;
-             udp1->checksum = 0;
-             udp_packets++;
-           }
-
-         /* 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:
+             old_port1 = vnet_buffer (b1)->ip.reass.l4_dst_port;
+             new_port1 = udp1->dst_port = s1->in2out.port;
+             if (PREDICT_FALSE (udp1->checksum))
+               {
 
-         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;
+                 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);
+               }
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.udp,
+                                        thread_index, sw_if_index1, 1);
+       }
 
-         pkts_processed += next1 == SNAT_OUT2IN_NEXT_LOOKUP;
+      /* 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:
 
-         /* 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 (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;
        }
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      if (next1 == SNAT_OUT2IN_NEXT_DROP)
        {
-         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;
-         snat_session_key_t key0, sm0;
-         u32 rx_fib_index0;
-         u32 proto0;
-         snat_session_t *s0 = 0;
-         clib_bihash_kv_8_8_t kv0, value0;
-         u8 identity_nat0;
-
-         /* 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_snat_proto (ip0->protocol);
-
-         if (PREDICT_FALSE (proto0 == ~0))
-           {
-             if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
-               {
-                 if (!sm->forwarding_enabled)
-                   {
-                     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.drops,
+                                        thread_index, sw_if_index1, 1);
+       }
 
-         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;
-           }
+      n_left_from -= 2;
+      next[0] = next0;
+      next[1] = next1;
+      next += 2;
+    }
 
-         if (PREDICT_FALSE (ip4_is_fragment (ip0)))
+  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))
+       {
+         if (nat_out2in_sm_unknown_proto (sm, b0, ip0, rx_fib_index0))
            {
-             next0 = SNAT_OUT2IN_NEXT_REASS;
-             fragments++;
-             goto trace00;
+             if (!sm->forwarding_enabled)
+               {
+                 b0->error =
+                   node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+                 next0 = SNAT_OUT2IN_NEXT_DROP;
+               }
            }
+         vlib_increment_simple_counter (&sm->counters.slowpath.out2in.other,
+                                        thread_index, sw_if_index0, 1);
+         goto trace00;
+       }
 
-         if (PREDICT_FALSE (proto0 == SNAT_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 (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;
+       }
 
-         key0.addr = ip0->dst_address;
-         key0.port = udp0->dst_port;
-         key0.protocol = proto0;
-         key0.fib_index = rx_fib_index0;
+      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;
+       }
 
-         kv0.key = key0.as_u64;
+      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, key0, &sm0, 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 == SNAT_PROTOCOL_UDP
-                                    && (udp0->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, sm0, key0, 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;
-
-         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 == SNAT_PROTOCOL_TCP))
+
+         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)
+           {
+             next0 = SNAT_OUT2IN_NEXT_DROP;
+             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;
+
+      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)
            {
-             old_port0 = tcp0->dst_port;
-             tcp0->dst_port = s0->in2out.port;
-             new_port0 = tcp0->dst_port;
+             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,
@@ -1277,62 +1307,65 @@ VLIB_NODE_FN (snat_out2in_node) (vlib_main_t * vm,
                                     ip4_header_t /* cheat */ ,
                                     length /* changed member */ );
              tcp0->checksum = ip_csum_fold (sum0);
-             tcp_packets++;
            }
-         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)
            {
-             old_port0 = udp0->dst_port;
-             udp0->dst_port = s0->in2out.port;
-             udp0->checksum = 0;
-             udp_packets++;
+             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);
+               }
            }
+         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;
 }
@@ -1356,507 +1389,167 @@ VLIB_REGISTER_NODE (snat_out2in_node) = {
     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
   },
 };
 /* *INDENT-ON* */
 
-VLIB_NODE_FN (nat44_out2in_reass_node) (vlib_main_t * vm,
-                                       vlib_node_runtime_t * node,
-                                       vlib_frame_t * frame)
+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, cached_fragments = 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 *per_thread_data =
-    &sm->per_thread_data[thread_index];
-  u32 *fragments_to_drop = 0;
-  u32 *fragments_to_loopback = 0;
 
   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_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
-
-      while (n_left_from > 0 && n_left_to_next > 0)
+      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))
        {
-         u32 bi0, sw_if_index0, proto0, rx_fib_index0, new_addr0, old_addr0;
-         vlib_buffer_t *b0;
-         u32 next0;
-         u8 cached0 = 0;
-         ip4_header_t *ip0;
-         nat_reass_ip4_t *reass0;
-         udp_header_t *udp0;
-         tcp_header_t *tcp0;
-         icmp46_header_t *icmp0;
-         snat_session_key_t key0, sm0;
-         clib_bihash_kv_8_8_t kv0, value0;
-         snat_session_t *s0 = 0;
-         u16 old_port0, new_port0;
-         ip_csum_t sum0;
-         u8 identity_nat0;
-
-         /* speculatively enqueue b0 to the current next frame */
-         bi0 = from[0];
-         to_next[0] = bi0;
-         from += 1;
-         to_next += 1;
-         n_left_from -= 1;
-         n_left_to_next -= 1;
-
-         b0 = vlib_get_buffer (vm, bi0);
-         next0 = SNAT_OUT2IN_NEXT_LOOKUP;
-
-         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 (nat_reass_is_drop_frag (0)))
-           {
-             next0 = SNAT_OUT2IN_NEXT_DROP;
-             b0->error = node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT];
-             goto trace0;
-           }
-
-         ip0 = (ip4_header_t *) vlib_buffer_get_current (b0);
-         udp0 = ip4_next_header (ip0);
-         tcp0 = (tcp_header_t *) udp0;
-         icmp0 = (icmp46_header_t *) udp0;
-         proto0 = ip_proto_to_snat_proto (ip0->protocol);
-
-         reass0 = nat_ip4_reass_find_or_create (ip0->src_address,
-                                                ip0->dst_address,
-                                                ip0->fragment_id,
-                                                ip0->protocol,
-                                                1, &fragments_to_drop);
-
-         if (PREDICT_FALSE (!reass0))
-           {
-             next0 = SNAT_OUT2IN_NEXT_DROP;
-             b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_REASS];
-             nat_elog_notice ("maximum reassemblies exceeded");
-             goto trace0;
-           }
-
-         if (PREDICT_FALSE (ip4_is_first_fragment (ip0)))
-           {
-             if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
-               {
-                 next0 = icmp_out2in_slow_path
-                   (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                    next0, now, thread_index, &s0);
-
-                 if (PREDICT_TRUE (next0 != SNAT_OUT2IN_NEXT_DROP))
-                   {
-                     if (s0)
-                       reass0->sess_index = s0 - per_thread_data->sessions;
-                     else
-                       reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
-                     reass0->thread_index = thread_index;
-                     nat_ip4_reass_get_frags (reass0,
-                                              &fragments_to_loopback);
-                   }
-
-                 goto trace0;
-               }
-
-             key0.addr = ip0->dst_address;
-             key0.port = udp0->dst_port;
-             key0.protocol = proto0;
-             key0.fib_index = rx_fib_index0;
-             kv0.key = key0.as_u64;
-
-             if (clib_bihash_search_8_8
-                 (&per_thread_data->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, key0, &sm0, 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 == SNAT_PROTOCOL_UDP
-                                        && (udp0->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;
-                       }
-                     else
-                       {
-                         reass0->flags |= NAT_REASS_FLAG_ED_DONT_TRANSLATE;
-                         nat_ip4_reass_get_frags (reass0,
-                                                  &fragments_to_loopback);
-                       }
-                     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, sm0, key0,
-                                                      node, thread_index,
-                                                      now);
-                 if (!s0)
-                   {
-                     b0->error =
-                       node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                     goto trace0;
-                   }
-                 reass0->sess_index = s0 - per_thread_data->sessions;
-                 reass0->thread_index = thread_index;
-               }
-             else
-               {
-                 s0 = pool_elt_at_index (per_thread_data->sessions,
-                                         value0.value);
-                 reass0->sess_index = value0.value;
-               }
-             nat_ip4_reass_get_frags (reass0, &fragments_to_loopback);
-           }
-         else
-           {
-             if (reass0->flags & NAT_REASS_FLAG_ED_DONT_TRANSLATE)
-               goto trace0;
-             if (PREDICT_FALSE (reass0->sess_index == (u32) ~ 0))
-               {
-                 if (nat_ip4_reass_add_fragment
-                     (thread_index, reass0, bi0, &fragments_to_drop))
-                   {
-                     b0->error = node->errors[SNAT_OUT2IN_ERROR_MAX_FRAG];
-                     nat_elog_notice
-                       ("maximum fragments per reassembly exceeded");
-                     next0 = SNAT_OUT2IN_NEXT_DROP;
-                     goto trace0;
-                   }
-                 cached0 = 1;
-                 goto trace0;
-               }
-             s0 = pool_elt_at_index (per_thread_data->sessions,
-                                     reass0->sess_index);
-           }
-
-         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_FALSE (ip4_is_first_fragment (ip0)))
-           {
-             if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
-               {
-                 old_port0 = tcp0->dst_port;
-                 tcp0->dst_port = s0->in2out.port;
-                 new_port0 = tcp0->dst_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
-               {
-                 old_port0 = udp0->dst_port;
-                 udp0->dst_port = s0->in2out.port;
-                 udp0->checksum = 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);
-
-       trace0:
-         if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
-                            && (b0->flags & VLIB_BUFFER_IS_TRACED)))
-           {
-             nat44_reass_trace_t *t =
-               vlib_add_trace (vm, node, b0, sizeof (*t));
-             t->cached = cached0;
-             t->sw_if_index = sw_if_index0;
-             t->next_index = next0;
-           }
-
-         if (cached0)
-           {
-             n_left_to_next++;
-             to_next--;
-             cached_fragments++;
-           }
-         else
-           {
-             pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
-
-             /* 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 (n_left_from == 0 && vec_len (fragments_to_loopback))
-           {
-             from = vlib_frame_vector_args (frame);
-             u32 len = vec_len (fragments_to_loopback);
-             if (len <= VLIB_FRAME_SIZE)
-               {
-                 clib_memcpy_fast (from, fragments_to_loopback,
-                                   sizeof (u32) * len);
-                 n_left_from = len;
-                 vec_reset_length (fragments_to_loopback);
-               }
-             else
-               {
-                 clib_memcpy_fast (from, fragments_to_loopback +
-                                   (len - VLIB_FRAME_SIZE),
-                                   sizeof (u32) * VLIB_FRAME_SIZE);
-                 n_left_from = VLIB_FRAME_SIZE;
-                 _vec_len (fragments_to_loopback) = len - VLIB_FRAME_SIZE;
-               }
-           }
+         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;
        }
 
-      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
-    }
-
-  vlib_node_increment_counter (vm, sm->out2in_reass_node_index,
-                              SNAT_OUT2IN_ERROR_PROCESSED_FRAGMENTS,
-                              pkts_processed);
-  vlib_node_increment_counter (vm, sm->out2in_reass_node_index,
-                              SNAT_OUT2IN_ERROR_CACHED_FRAGMENTS,
-                              cached_fragments);
-
-  nat_send_all_to_node (vm, fragments_to_drop, node,
-                       &node->errors[SNAT_OUT2IN_ERROR_DROP_FRAGMENT],
-                       SNAT_OUT2IN_NEXT_DROP);
+      proto0 = ip_proto_to_nat_proto (ip0->protocol);
 
-  vec_free (fragments_to_drop);
-  vec_free (fragments_to_loopback);
-  return frame->n_vectors;
-}
-
-/* *INDENT-OFF* */
-VLIB_REGISTER_NODE (nat44_out2in_reass_node) = {
-  .name = "nat44-out2in-reass",
-  .vector_size = sizeof (u32),
-  .format_trace = format_nat44_reass_trace,
-  .type = VLIB_NODE_TYPE_INTERNAL,
-
-  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
-  .error_strings = snat_out2in_error_strings,
-
-  .n_next_nodes = SNAT_OUT2IN_N_NEXT,
+      if (PREDICT_FALSE (proto0 == NAT_PROTOCOL_OTHER))
+       goto trace00;
 
-  /* edit / add dispositions here */
-  .next_nodes = {
-    [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
-    [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
-    [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
-  },
-};
-/* *INDENT-ON* */
-
-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;
-  snat_main_t *sm = &snat_main;
+      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;
+       }
 
-  from = vlib_frame_vector_args (frame);
-  n_left_from = frame->n_vectors;
-  next_index = node->cached_next_index;
+      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;
+       }
 
-  while (n_left_from > 0)
-    {
-      u32 n_left_to_next;
+      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;
 
-      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+      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);
 
-      while (n_left_from > 0 && n_left_to_next > 0)
+      if (PREDICT_FALSE (new_port0 != udp0->dst_port))
        {
-         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;
-         snat_session_key_t key0, sm0;
-         u32 proto0;
-         u32 rx_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;
-           }
-
-         proto0 = ip_proto_to_snat_proto (ip0->protocol);
+         old_port0 = udp0->dst_port;
+         udp0->dst_port = new_port0;
 
-         if (PREDICT_FALSE (proto0 == ~0))
-           goto trace00;
-
-         if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
+         if (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
            {
-             next0 = icmp_out2in (sm, b0, ip0, icmp0, sw_if_index0,
-                                  rx_fib_index0, node, next0, ~0, 0, 0);
-             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);
            }
-
-         key0.addr = ip0->dst_address;
-         key0.port = udp0->dst_port;
-         key0.fib_index = rx_fib_index0;
-
-         if (snat_static_mapping_match (sm, key0, &sm0, 1, 0, 0, 0, 0, 0))
+         else if (udp0->checksum)
            {
-             b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
-             goto trace00;
+             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);
            }
-
-         new_addr0 = sm0.addr.as_u32;
-         new_port0 = sm0.port;
-         vnet_buffer (b0)->sw_if_index[VLIB_TX] = sm0.fib_index;
-         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 (PREDICT_TRUE (proto0 == NAT_PROTOCOL_TCP))
            {
-             if (PREDICT_TRUE (proto0 == SNAT_PROTOCOL_TCP))
-               {
-                 old_port0 = tcp0->dst_port;
-                 tcp0->dst_port = new_port0;
-
-                 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
-               {
-                 old_port0 = udp0->dst_port;
-                 udp0->dst_port = new_port0;
-                 udp0->checksum = 0;
-               }
+             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
+         else if (udp0->checksum)
            {
-             if (PREDICT_TRUE (proto0 == SNAT_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);
-               }
+             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:
+    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;
-           }
-
-         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;
 }
 
@@ -1879,7 +1572,6 @@ VLIB_REGISTER_NODE (snat_out2in_fast_node) = {
     [SNAT_OUT2IN_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
     [SNAT_OUT2IN_NEXT_ICMP_ERROR] = "ip4-icmp-error",
-    [SNAT_OUT2IN_NEXT_REASS] = "nat44-out2in-reass",
   },
 };
 /* *INDENT-ON* */