SNAT: in2out translation as an output feature hairpinning (VPP-913)
[vpp.git] / src / plugins / snat / out2in.c
index b52402c..329d67d 100644 (file)
@@ -86,7 +86,7 @@ vlib_node_registration_t snat_det_out2in_node;
 #define foreach_snat_out2in_error                       \
 _(UNSUPPORTED_PROTOCOL, "Unsupported protocol")         \
 _(OUT2IN_PACKETS, "Good out2in packets processed")      \
-_(BAD_ICMP_TYPE, "icmp type not echo-reply")            \
+_(BAD_ICMP_TYPE, "unsupported ICMP type")               \
 _(NO_TRANSLATION, "No translation")
   
 typedef enum {
@@ -137,6 +137,9 @@ create_session_for_static_mapping (snat_main_t *sm,
   clib_bihash_kv_8_8_t kv0, value0;
   dlist_elt_t * per_user_translation_list_elt;
   dlist_elt_t * per_user_list_head_elt;
+  ip4_header_t *ip0;
+
+  ip0 = vlib_buffer_get_current (b0);
 
   user_key.addr = in2out.addr;
   user_key.fib_index = in2out.fib_index;
@@ -180,6 +183,7 @@ create_session_for_static_mapping (snat_main_t *sm,
 
   s->outside_address_index = ~0;
   s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+  s->ext_host_addr.as_u32 = ip0->dst_address.as_u32;
   u->nstaticsessions++;
 
   /* Create list elts */
@@ -271,31 +275,6 @@ snat_out2in_error_t icmp_get_key(ip4_header_t *ip0,
   return -1; /* success */
 }
 
-static_always_inline u8
-is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
-                  u32 ip4_addr)
-{
-  snat_runtime_t *rt = (snat_runtime_t *) node->runtime_data;
-  ip4_address_t * first_int_addr;
-
-  if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
-    {
-      first_int_addr =
-        ip4_interface_first_address (sm->ip4_main, sw_if_index0,
-                                     0 /* just want the address */);
-      rt->cached_sw_if_index = sw_if_index0;
-      if (first_int_addr)
-        rt->cached_ip4_address = first_int_addr->as_u32;
-      else
-        rt->cached_ip4_address = 0;
-    }
-
-  if (PREDICT_FALSE(ip4_addr == rt->cached_ip4_address))
-    return 1;
-  else
-    return 0;
-}
-
 /**
  * Get address and port values to be used for packet SNAT translation
  * and create session if needed
@@ -304,16 +283,16 @@ is_interface_addr(snat_main_t *sm, vlib_node_runtime_t *node, u32 sw_if_index0,
  * @param[in,out] node           SNAT node runtime
  * @param[in] thread_index       thread index
  * @param[in,out] b0             buffer containing packet to be translated
- * @param[out] p_key             address and port before NAT translation
+ * @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
  * @param d                      optional parameter
+ * @param e                      optional parameter
  */
 u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
-                           u32 thread_index, vlib_buffer_t *b0,
-                           snat_session_key_t *p_key,
+                           u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
                            snat_session_key_t *p_value,
-                           u8 *p_dont_translate, void *d)
+                           u8 *p_dont_translate, void *d, void *e)
 {
   ip4_header_t *ip0;
   icmp46_header_t *icmp0;
@@ -324,6 +303,7 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
   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;
 
@@ -332,6 +312,8 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
   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);
 
+  key0.protocol = 0;
+
   err = icmp_get_key (ip0, &key0);
   if (err != -1)
     {
@@ -347,11 +329,11 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
     {
       /* 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))
+      if (snat_static_mapping_match(sm, key0, &sm0, 1, &is_addr_only))
         {
           /* Don't NAT packet aimed at the intfc address */
-          if (is_interface_addr(sm, node, sw_if_index0,
-                                ip0->dst_address.as_u32))
+          if (PREDICT_FALSE(is_interface_addr(sm, node, sw_if_index0,
+                                              ip0->dst_address.as_u32)))
             {
               dont_translate = 1;
               goto out;
@@ -361,8 +343,10 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
           goto out;
         }
 
-      if (icmp_is_error_message (icmp0))
+      if (PREDICT_FALSE(icmp0->type != ICMP4_echo_reply &&
+                        (icmp0->type != ICMP4_echo_request || !is_addr_only)))
         {
+          b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
           next0 = SNAT_OUT2IN_NEXT_DROP;
           goto out;
         }
@@ -378,11 +362,22 @@ u32 icmp_match_out2in_slow(snat_main_t *sm, vlib_node_runtime_t *node,
         }
     }
   else
-    s0 = pool_elt_at_index (sm->per_thread_data[thread_index].sessions,
-                            value0.value);
+    {
+      if (PREDICT_FALSE(icmp0->type != ICMP4_echo_reply &&
+                        icmp0->type != ICMP4_echo_request &&
+                        !icmp_is_error_message (icmp0)))
+        {
+          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);
+    }
 
 out:
-  *p_key = key0;
+  *p_proto = key0.protocol;
   if (s0)
     *p_value = s0->in2out;
   *p_dont_translate = dont_translate;
@@ -398,27 +393,30 @@ out:
  * @param[in,out] node           SNAT node runtime
  * @param[in] thread_index       thread index
  * @param[in,out] b0             buffer containing packet to be translated
- * @param[out] p_key             address and port before NAT translation
+ * @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
  * @param d                      optional parameter
+ * @param e                      optional parameter
  */
 u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
-                           u32 thread_index, vlib_buffer_t *b0,
-                           snat_session_key_t *p_key,
+                           u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
                            snat_session_key_t *p_value,
-                           u8 *p_dont_translate, void *d)
+                           u8 *p_dont_translate, void *d, void *e)
 {
   ip4_header_t *ip0;
+  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;
 
   ip0 = vlib_buffer_get_current (b0);
+  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);
 
@@ -431,7 +429,7 @@ u32 icmp_match_out2in_fast(snat_main_t *sm, vlib_node_runtime_t *node,
     }
   key0.fib_index = rx_fib_index0;
 
-  if (snat_static_mapping_match(sm, key0, &sm0, 1))
+  if (snat_static_mapping_match(sm, key0, &sm0, 1, &is_addr_only))
     {
       /* Don't NAT packet aimed at the intfc address */
       if (is_interface_addr(sm, node, sw_if_index0, ip0->dst_address.as_u32))
@@ -444,10 +442,19 @@ u32 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)))
+    {
+      b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
+      next0 = SNAT_OUT2IN_NEXT_DROP;
+      goto out;
+    }
+
 out:
   *p_value = sm0;
 out2:
-  *p_key = key0;
+  *p_proto = key0.protocol;
   *p_dont_translate = dont_translate;
   return next0;
 }
@@ -461,9 +468,11 @@ static inline u32 icmp_out2in (snat_main_t *sm,
                                vlib_node_runtime_t * node,
                                u32 next0,
                                u32 thread_index,
-                               void *d)
+                               void *d,
+                               void *e)
 {
-  snat_session_key_t key0, sm0;
+  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;
@@ -478,20 +487,12 @@ static inline u32 icmp_out2in (snat_main_t *sm,
   echo0 = (icmp_echo_header_t *)(icmp0+1);
 
   next0_tmp = sm->icmp_match_out2in_cb(sm, node, thread_index, b0,
-                                       &key0, &sm0, &dont_translate, d);
+                                       &protocol, &sm0, &dont_translate, d, e);
   if (next0_tmp != ~0)
     next0 = next0_tmp;
   if (next0 == SNAT_OUT2IN_NEXT_DROP || dont_translate)
     goto out;
 
-  if (PREDICT_FALSE(icmp0->type != ICMP4_echo_reply &&
-                    !icmp_is_error_message (icmp0)))
-    {
-      b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
-      next0 = SNAT_OUT2IN_NEXT_DROP;
-      goto out;
-    }
-
   sum0 = ip_incremental_checksum (0, icmp0,
                                   ntohs(ip0->length) - ip4_header_bytes (ip0));
   checksum0 = ~ip_csum_fold (sum0);
@@ -545,7 +546,7 @@ static inline u32 icmp_out2in (snat_main_t *sm,
                              src_address /* changed member */);
       icmp0->checksum = ip_csum_fold (sum0);
 
-      switch (key0.protocol)
+      switch (protocol)
         {
         case SNAT_PROTOCOL_ICMP:
           inner_icmp0 = (icmp46_header_t*)l4_header;
@@ -593,7 +594,7 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
                                          snat_session_t ** p_s0)
 {
   next0 = icmp_out2in(sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                      next0, thread_index, p_s0);
+                      next0, thread_index, p_s0, 0);
   snat_session_t * s0 = *p_s0;
   if (PREDICT_TRUE(next0 != SNAT_OUT2IN_NEXT_DROP && s0))
     {
@@ -614,6 +615,140 @@ static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
   return next0;
 }
 
+static void
+snat_out2in_unknown_proto (snat_main_t *sm,
+                           vlib_buffer_t * b,
+                           ip4_header_t * ip,
+                           u32 rx_fib_index,
+                           u32 thread_index,
+                           f64 now,
+                           vlib_main_t * vm)
+{
+  clib_bihash_kv_8_8_t kv, value;
+  clib_bihash_kv_16_8_t s_kv, s_value;
+  snat_static_mapping_t *m;
+  snat_session_key_t m_key;
+  u32 old_addr, new_addr;
+  ip_csum_t sum;
+  snat_unk_proto_ses_key_t key;
+  snat_session_t * s;
+  snat_main_per_thread_data_t *tsm = &sm->per_thread_data[thread_index];
+  snat_user_key_t u_key;
+  snat_user_t *u;
+  dlist_elt_t *head, *elt;
+
+  old_addr = ip->dst_address.as_u32;
+
+  key.l_addr = ip->dst_address;
+  key.r_addr = ip->src_address;
+  key.fib_index = rx_fib_index;
+  key.proto = ip->protocol;
+  key.rsvd[0] = key.rsvd[1] = key.rsvd[2] = 0;
+  s_kv.key[0] = key.as_u64[0];
+  s_kv.key[1] = key.as_u64[1];
+
+  if (!clib_bihash_search_16_8 (&sm->out2in_unk_proto, &s_kv, &s_value))
+    {
+      s = pool_elt_at_index (tsm->sessions, s_value.value);
+      new_addr = ip->dst_address.as_u32 = s->in2out.addr.as_u32;
+    }
+  else
+    {
+      m_key.addr = ip->dst_address;
+      m_key.port = 0;
+      m_key.protocol = 0;
+      m_key.fib_index = rx_fib_index;
+      kv.key = m_key.as_u64;
+      if (clib_bihash_search_8_8 (&sm->static_mapping_by_external, &kv, &value))
+        return;
+
+      m = pool_elt_at_index (sm->static_mappings, value.value);
+
+      new_addr = ip->dst_address.as_u32 = m->local_addr.as_u32;
+
+      u_key.addr = ip->src_address;
+      u_key.fib_index = m->fib_index;
+      kv.key = u_key.as_u64;
+
+      /* Ever heard of the "user" = src ip4 address before? */
+      if (clib_bihash_search_8_8 (&sm->user_hash, &kv, &value))
+        {
+          /* no, make a new one */
+          pool_get (tsm->users, u);
+          memset (u, 0, sizeof (*u));
+          u->addr = ip->src_address;
+          u->fib_index = rx_fib_index;
+
+          pool_get (tsm->list_pool, head);
+          u->sessions_per_user_list_head_index = head - tsm->list_pool;
+
+          clib_dlist_init (tsm->list_pool,
+                           u->sessions_per_user_list_head_index);
+
+          kv.value = u - tsm->users;
+
+          /* add user */
+          clib_bihash_add_del_8_8 (&sm->user_hash, &kv, 1);
+        }
+      else
+        {
+          u = pool_elt_at_index (tsm->users, value.value);
+        }
+
+      /* Create a new session */
+      pool_get (tsm->sessions, s);
+      memset (s, 0, sizeof (*s));
+
+      s->ext_host_addr.as_u32 = ip->src_address.as_u32;
+      s->flags |= SNAT_SESSION_FLAG_UNKNOWN_PROTO;
+      s->flags |= SNAT_SESSION_FLAG_STATIC_MAPPING;
+      s->outside_address_index = ~0;
+      s->out2in.addr.as_u32 = old_addr;
+      s->out2in.fib_index = rx_fib_index;
+      s->in2out.addr.as_u32 = new_addr;
+      s->in2out.fib_index = m->fib_index;
+      s->in2out.port = s->out2in.port = ip->protocol;
+      u->nstaticsessions++;
+
+      /* Create list elts */
+      pool_get (tsm->list_pool, elt);
+      clib_dlist_init (tsm->list_pool, elt - tsm->list_pool);
+      elt->value = s - tsm->sessions;
+      s->per_user_index = elt - tsm->list_pool;
+      s->per_user_list_head_index = u->sessions_per_user_list_head_index;
+      clib_dlist_addtail (tsm->list_pool, s->per_user_list_head_index,
+                          s->per_user_index);
+
+      /* Add to lookup tables */
+      s_kv.value = s - tsm->sessions;
+      if (clib_bihash_add_del_16_8 (&sm->out2in_unk_proto, &s_kv, 1))
+        clib_warning ("out2in key add failed");
+
+      key.l_addr = ip->dst_address;
+      key.fib_index = m->fib_index;
+      s_kv.key[0] = key.as_u64[0];
+      s_kv.key[1] = key.as_u64[1];
+      if (clib_bihash_add_del_16_8 (&sm->in2out_unk_proto, &s_kv, 1))
+        clib_warning ("in2out key add failed");
+   }
+
+  /* Update IP checksum */
+  sum = ip->checksum;
+  sum = ip_csum_update (sum, old_addr, new_addr, ip4_header_t, dst_address);
+  ip->checksum = ip_csum_fold (sum);
+
+  vnet_buffer(b)->sw_if_index[VLIB_TX] = s->in2out.fib_index;
+
+  /* Accounting */
+  s->last_heard = now;
+  s->total_pkts++;
+  s->total_bytes += vlib_buffer_length_in_chain (vm, b);
+  /* Per-user LRU list maintenance */
+  clib_dlist_remove (tsm->list_pool, s->per_user_index);
+  clib_dlist_addtail (tsm->list_pool, s->per_user_list_head_index,
+                      s->per_user_index);
+}
+
 static uword
 snat_out2in_node_fn (vlib_main_t * vm,
                  vlib_node_runtime_t * node,
@@ -683,7 +818,10 @@ snat_out2in_node_fn (vlib_main_t * vm,
 
          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;
@@ -706,7 +844,11 @@ snat_out2in_node_fn (vlib_main_t * vm,
           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 
           if (PREDICT_FALSE (proto0 == ~0))
+            {
+              snat_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
+                                        thread_index, now, vm);
               goto trace0;
+            }
 
           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
             {
@@ -727,7 +869,7 @@ snat_out2in_node_fn (vlib_main_t * vm,
             {
               /* 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))
+              if (snat_static_mapping_match(sm, key0, &sm0, 1, 0))
                 {
                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                   /* 
@@ -841,7 +983,11 @@ snat_out2in_node_fn (vlib_main_t * vm,
           proto1 = ip_proto_to_snat_proto (ip1->protocol);
 
           if (PREDICT_FALSE (proto1 == ~0))
+            {
+              snat_out2in_unknown_proto(sm, b1, ip1, rx_fib_index1,
+                                        thread_index, now, vm);
               goto trace1;
+            }
 
           if (PREDICT_FALSE (proto1 == SNAT_PROTOCOL_ICMP))
             {
@@ -862,7 +1008,7 @@ snat_out2in_node_fn (vlib_main_t * vm,
             {
               /* 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))
+              if (snat_static_mapping_match(sm, key1, &sm1, 1, 0))
                 {
                   b1->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                   /* 
@@ -988,6 +1134,8 @@ snat_out2in_node_fn (vlib_main_t * vm,
 
          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;
@@ -1000,7 +1148,11 @@ snat_out2in_node_fn (vlib_main_t * vm,
           proto0 = ip_proto_to_snat_proto (ip0->protocol);
 
           if (PREDICT_FALSE (proto0 == ~0))
+            {
+              snat_out2in_unknown_proto(sm, b0, ip0, rx_fib_index0,
+                                        thread_index, now, vm);
               goto trace00;
+            }
 
           if (PREDICT_FALSE(ip0->ttl == 1))
             {
@@ -1031,7 +1183,7 @@ snat_out2in_node_fn (vlib_main_t * vm,
             {
               /* 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))
+              if (snat_static_mapping_match(sm, key0, &sm0, 1, 0))
                 {
                   b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
                   /* 
@@ -1173,6 +1325,7 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
   snat_out2in_next_t next_index;
   u32 pkts_processed = 0;
   snat_main_t * sm = &snat_main;
+  u32 thread_index = vlib_get_thread_index ();
 
   from = vlib_frame_vector_args (frame);
   n_left_from = frame->n_vectors;
@@ -1202,6 +1355,8 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
           snat_det_out_key_t key0, key1;
           snat_det_map_t * dm0, * dm1;
           snat_det_session_t * ses0 = 0, * ses1 = 0;
+          u32 rx_fib_index0, rx_fib_index1;
+          icmp46_header_t * icmp0, * icmp1;
 
          /* Prefetch next iteration. */
          {
@@ -1244,6 +1399,19 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
               goto trace0;
             }
 
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          if (PREDICT_FALSE(proto0 == SNAT_PROTOCOL_ICMP))
+            {
+              rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index(sw_if_index0);
+              icmp0 = (icmp46_header_t *) udp0;
+
+              next0 = icmp_out2in(sm, b0, ip0, icmp0, sw_if_index0,
+                                  rx_fib_index0, node, next0, thread_index,
+                                  &ses0, &dm0);
+              goto trace0;
+            }
+
           key0.ext_host_addr = ip0->src_address;
           key0.ext_host_port = tcp0->src;
           key0.out_port = tcp0->dst;
@@ -1276,8 +1444,6 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
             }
           new_port0 = ses0->in_port;
 
-          proto0 = ip_proto_to_snat_proto (ip0->protocol);
-
           old_addr0 = ip0->dst_address;
           ip0->dst_address = new_addr0;
           vnet_buffer(b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
@@ -1349,6 +1515,19 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
               goto trace1;
             }
 
+          proto1 = ip_proto_to_snat_proto (ip1->protocol);
+
+          if (PREDICT_FALSE(proto1 == SNAT_PROTOCOL_ICMP))
+            {
+              rx_fib_index1 = ip4_fib_table_get_index_for_sw_if_index(sw_if_index1);
+              icmp1 = (icmp46_header_t *) udp1;
+
+              next1 = icmp_out2in(sm, b1, ip1, icmp1, sw_if_index1,
+                                  rx_fib_index1, node, next1, thread_index,
+                                  &ses1, &dm1);
+              goto trace1;
+            }
+
           key1.ext_host_addr = ip1->src_address;
           key1.ext_host_port = tcp1->src;
           key1.out_port = tcp1->dst;
@@ -1381,8 +1560,6 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
             }
           new_port1 = ses1->in_port;
 
-          proto1 = ip_proto_to_snat_proto (ip1->protocol);
-
           old_addr1 = ip1->dst_address;
           ip1->dst_address = new_addr1;
           vnet_buffer(b1)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
@@ -1458,6 +1635,8 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
           snat_det_out_key_t key0;
           snat_det_map_t * dm0;
           snat_det_session_t * ses0 = 0;
+          u32 rx_fib_index0;
+          icmp46_header_t * icmp0;
 
           /* speculatively enqueue b0 to the current next frame */
          bi0 = from[0];
@@ -1485,6 +1664,19 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
               goto trace00;
             }
 
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          if (PREDICT_FALSE(proto0 == SNAT_PROTOCOL_ICMP))
+            {
+              rx_fib_index0 = ip4_fib_table_get_index_for_sw_if_index(sw_if_index0);
+              icmp0 = (icmp46_header_t *) udp0;
+
+              next0 = icmp_out2in(sm, b0, ip0, icmp0, sw_if_index0,
+                                  rx_fib_index0, node, next0, thread_index,
+                                  &ses0, &dm0);
+              goto trace00;
+            }
+
           key0.ext_host_addr = ip0->src_address;
           key0.ext_host_port = tcp0->src;
           key0.out_port = tcp0->dst;
@@ -1517,8 +1709,6 @@ snat_det_out2in_node_fn (vlib_main_t * vm,
             }
           new_port0 = ses0->in_port;
 
-          proto0 = ip_proto_to_snat_proto (ip0->protocol);
-
           old_addr0 = ip0->dst_address;
           ip0->dst_address = new_addr0;
           vnet_buffer(b0)->sw_if_index[VLIB_TX] = sm->inside_fib_index;
@@ -1610,6 +1800,146 @@ VLIB_REGISTER_NODE (snat_det_out2in_node) = {
 };
 VLIB_NODE_FUNCTION_MULTIARCH (snat_det_out2in_node, snat_det_out2in_node_fn);
 
+/**
+ * Get address and port values to be used for packet SNAT translation
+ * and create session if needed
+ *
+ * @param[in,out] sm             SNAT main
+ * @param[in,out] node           SNAT node runtime
+ * @param[in] thread_index       thread index
+ * @param[in,out] b0             buffer containing packet to be translated
+ * @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
+ * @param d                      optional parameter
+ * @param e                      optional parameter
+ */
+u32 icmp_match_out2in_det(snat_main_t *sm, vlib_node_runtime_t *node,
+                          u32 thread_index, vlib_buffer_t *b0, u8 *p_proto,
+                          snat_session_key_t *p_value,
+                          u8 *p_dont_translate, void *d, void *e)
+{
+  ip4_header_t *ip0;
+  icmp46_header_t *icmp0;
+  u32 sw_if_index0;
+  u8 protocol;
+  snat_det_out_key_t key0;
+  u8 dont_translate = 0;
+  u32 next0 = ~0;
+  icmp_echo_header_t *echo0, *inner_echo0 = 0;
+  ip4_header_t *inner_ip0;
+  void *l4_header = 0;
+  icmp46_header_t *inner_icmp0;
+  snat_det_map_t * dm0 = 0;
+  ip4_address_t new_addr0 = {{0}};
+  snat_det_session_t * ses0 = 0;
+  ip4_address_t out_addr;
+
+  ip0 = vlib_buffer_get_current (b0);
+  icmp0 = (icmp46_header_t *) ip4_next_header (ip0);
+  echo0 = (icmp_echo_header_t *)(icmp0+1);
+  sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_RX];
+
+  if (!icmp_is_error_message (icmp0))
+    {
+      protocol = SNAT_PROTOCOL_ICMP;
+      key0.ext_host_addr = ip0->src_address;
+      key0.ext_host_port = 0;
+      key0.out_port = echo0->identifier;
+      out_addr = ip0->dst_address;
+    }
+  else
+    {
+      inner_ip0 = (ip4_header_t *)(echo0+1);
+      l4_header = ip4_next_header (inner_ip0);
+      protocol = ip_proto_to_snat_proto (inner_ip0->protocol);
+      key0.ext_host_addr = inner_ip0->dst_address;
+      out_addr = inner_ip0->src_address;
+      switch (protocol)
+        {
+        case SNAT_PROTOCOL_ICMP:
+          inner_icmp0 = (icmp46_header_t*)l4_header;
+          inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
+          key0.ext_host_port = 0;
+          key0.out_port = inner_echo0->identifier;
+          break;
+        case SNAT_PROTOCOL_UDP:
+        case SNAT_PROTOCOL_TCP:
+          key0.ext_host_port = ((tcp_udp_header_t*)l4_header)->dst_port;
+          key0.out_port = ((tcp_udp_header_t*)l4_header)->src_port;
+          break;
+        default:
+          b0->error = node->errors[SNAT_OUT2IN_ERROR_UNSUPPORTED_PROTOCOL];
+          next0 = SNAT_OUT2IN_NEXT_DROP;
+          goto out;
+        }
+    }
+
+  dm0 = snat_det_map_by_out(sm, &out_addr);
+  if (PREDICT_FALSE(!dm0))
+    {
+      /* Don't NAT packet aimed at the intfc address */
+      if (PREDICT_FALSE(is_interface_addr(sm, node, sw_if_index0,
+                                          ip0->dst_address.as_u32)))
+        {
+          dont_translate = 1;
+          goto out;
+        }
+      clib_warning("unknown dst address:  %U",
+                   format_ip4_address, &ip0->dst_address);
+      goto out;
+    }
+
+  snat_det_reverse(dm0, &ip0->dst_address,
+                   clib_net_to_host_u16(key0.out_port), &new_addr0);
+
+  ses0 = snat_det_get_ses_by_out (dm0, &new_addr0, key0.as_u64);
+  if (PREDICT_FALSE(!ses0))
+    {
+      /* Don't NAT packet aimed at the intfc address */
+      if (PREDICT_FALSE(is_interface_addr(sm, node, sw_if_index0,
+                                          ip0->dst_address.as_u32)))
+        {
+          dont_translate = 1;
+          goto out;
+        }
+      clib_warning("no match src %U:%d dst %U:%d for user %U",
+                   format_ip4_address, &key0.ext_host_addr,
+                   clib_net_to_host_u16 (key0.ext_host_port),
+                   format_ip4_address, &out_addr,
+                   clib_net_to_host_u16 (key0.out_port),
+                   format_ip4_address, &new_addr0);
+      b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+      next0 = SNAT_OUT2IN_NEXT_DROP;
+      goto out;
+    }
+
+  if (PREDICT_FALSE(icmp0->type != ICMP4_echo_reply &&
+                    !icmp_is_error_message (icmp0)))
+    {
+      b0->error = node->errors[SNAT_OUT2IN_ERROR_BAD_ICMP_TYPE];
+      next0 = SNAT_OUT2IN_NEXT_DROP;
+      goto out;
+    }
+
+  goto out;
+
+out:
+  *p_proto = protocol;
+  if (ses0)
+    {
+      p_value->addr = new_addr0;
+      p_value->fib_index = sm->inside_fib_index;
+      p_value->port = ses0->in_port;
+    }
+  *p_dont_translate = dont_translate;
+  if (d)
+    *(snat_det_session_t**)d = ses0;
+  if (e)
+    *(snat_det_map_t**)e = dm0;
+  return next0;
+}
+
 /**********************/
 /*** worker handoff ***/
 /**********************/
@@ -1849,7 +2179,7 @@ snat_out2in_fast_node_fn (vlib_main_t * vm,
           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
             {
               next0 = icmp_out2in(sm, b0, ip0, icmp0, sw_if_index0,
-                                  rx_fib_index0, node, next0, ~0, 0);
+                                  rx_fib_index0, node, next0, ~0, 0, 0);
               goto trace00;
             }
 
@@ -1857,7 +2187,7 @@ snat_out2in_fast_node_fn (vlib_main_t * vm,
           key0.port = udp0->dst_port;
           key0.fib_index = rx_fib_index0;
 
-          if (snat_static_mapping_match(sm, key0, &sm0, 1))
+          if (snat_static_mapping_match(sm, key0, &sm0, 1, 0))
             {
               b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
               goto trace00;