VPP-598: tcp stack initial commit
[vpp.git] / src / plugins / snat / in2out.c
index cd8f127..b4b7793 100644 (file)
@@ -22,6 +22,7 @@
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/fib/ip4_fib.h>
 #include <snat/snat.h>
+#include <snat/snat_ipfix_logging.h>
 
 #include <vppinfra/hash.h>
 #include <vppinfra/error.h>
@@ -111,9 +112,97 @@ typedef enum {
   SNAT_IN2OUT_NEXT_LOOKUP,
   SNAT_IN2OUT_NEXT_DROP,
   SNAT_IN2OUT_NEXT_SLOW_PATH,
+  SNAT_IN2OUT_NEXT_ICMP_ERROR,
   SNAT_IN2OUT_N_NEXT,
 } snat_in2out_next_t;
 
+/**
+ * @brief Check if packet should be translated
+ *
+ * Packets aimed at outside interface and external addresss with active session
+ * should be translated.
+ *
+ * @param sm            SNAT main
+ * @param rt            SNAT runtime data
+ * @param sw_if_index0  index of the inside interface
+ * @param ip0           IPv4 header
+ * @param proto0        SNAT protocol
+ * @param rx_fib_index0 RX FIB index
+ *
+ * @returns 0 if packet should be translated otherwise 1
+ */
+static inline int
+snat_not_translate (snat_main_t * sm, snat_runtime_t * rt, u32 sw_if_index0,
+                   ip4_header_t * ip0, u32 proto0, u32 rx_fib_index0)
+{
+  ip4_address_t * first_int_addr;
+  udp_header_t * udp0 = ip4_next_header (ip0);
+  snat_session_key_t key0, sm0;
+  clib_bihash_kv_8_8_t kv0, value0;
+  fib_node_index_t fei = FIB_NODE_INDEX_INVALID;
+  fib_prefix_t pfx = {
+    .fp_proto = FIB_PROTOCOL_IP4,
+    .fp_len = 32,
+    .fp_addr = {
+        .ip4.as_u32 = ip0->dst_address.as_u32,
+    },
+  };
+
+  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;
+    }
+
+  /* Don't NAT packet aimed at the intfc address */
+  if (PREDICT_FALSE(ip0->dst_address.as_u32 == rt->cached_ip4_address))
+    return 1;
+
+  key0.addr = ip0->dst_address;
+  key0.port = udp0->dst_port;
+  key0.protocol = proto0;
+  key0.fib_index = sm->outside_fib_index;
+  kv0.key = key0.as_u64;
+
+  /* NAT packet aimed at external address if */
+  /* has active sessions */
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+    {
+      /* or is static mappings */
+      if (!snat_static_mapping_match(sm, key0, &sm0, 1))
+        return 0;
+    }
+  else
+    return 0;
+
+  fei = fib_table_lookup (rx_fib_index0, &pfx);
+  if (FIB_NODE_INDEX_INVALID != fei)
+    {
+      u32 sw_if_index = fib_entry_get_resolving_interface (fei);
+      if (sw_if_index == ~0)
+        {
+          fei = fib_table_lookup (sm->outside_fib_index, &pfx);
+          if (FIB_NODE_INDEX_INVALID != fei)
+            sw_if_index = fib_entry_get_resolving_interface (fei);
+        }
+      snat_interface_t *i;
+      pool_foreach (i, sm->interfaces,
+      ({
+        /* NAT packet aimed at outside interface */
+        if ((i->is_inside == 0) && (sw_if_index == i->sw_if_index))
+          return 0;
+      }));
+    }
+
+  return 1;
+}
+
 static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
                       ip4_header_t * ip0,
                       u32 rx_fib_index0,
@@ -136,7 +225,7 @@ static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
   u32 address_index = ~0;
   u32 outside_fib_index;
   uword * p;
-  snat_static_mapping_key_t worker_by_out_key;
+  snat_worker_key_t worker_by_out_key;
 
   p = hash_get (sm->ip4_main->fib_index_by_table_id, sm->outside_vrf_id);
   if (! p)
@@ -146,6 +235,7 @@ static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
     }
   outside_fib_index = p[0];
 
+  key1.protocol = key0->protocol;
   user_key.addr = ip0->src_address;
   user_key.fib_index = rx_fib_index0;
   kv0.key = user_key.as_u64;
@@ -213,6 +303,14 @@ static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
       if (clib_bihash_add_del_8_8 (&sm->out2in, &kv0, 0 /* is_add */))
           clib_warning ("out2in key delete failed");
 
+      /* log NAT event */
+      snat_ipfix_logging_nat44_ses_delete(s->in2out.addr.as_u32,
+                                          s->out2in.addr.as_u32,
+                                          s->in2out.protocol,
+                                          s->in2out.port,
+                                          s->out2in.port,
+                                          s->in2out.fib_index);
+
       snat_free_outside_address_and_port 
         (sm, &s->out2in, s->outside_address_index);
       s->outside_address_index = ~0;
@@ -302,9 +400,21 @@ static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
   kv0.key = worker_by_out_key.as_u64;
   kv0.value = cpu_index;
   clib_bihash_add_del_8_8 (&sm->worker_by_out, &kv0, 1);
+
+  /* log NAT event */
+  snat_ipfix_logging_nat44_ses_create(s->in2out.addr.as_u32,
+                                      s->out2in.addr.as_u32,
+                                      s->in2out.protocol,
+                                      s->in2out.port,
+                                      s->out2in.port,
+                                      s->in2out.fib_index);
   return next0;
 }
                       
+typedef struct {
+  u16 src_port, dst_port;
+} tcp_udp_header_t;
+
 static inline u32 icmp_in2out_slow_path (snat_main_t *sm,
                                          vlib_buffer_t * b0,
                                          ip4_header_t * ip0,
@@ -314,82 +424,171 @@ static inline u32 icmp_in2out_slow_path (snat_main_t *sm,
                                          vlib_node_runtime_t * node,
                                          u32 next0,
                                          f64 now,
-                                         u32 cpu_index)
+                                         u32 cpu_index,
+                                         snat_session_t ** p_s0)
 {
   snat_session_key_t key0;
-  icmp_echo_header_t *echo0;
+  icmp_echo_header_t *echo0, *inner_echo0 = 0;
+  ip4_header_t *inner_ip0;
+  void *l4_header = 0;
+  icmp46_header_t *inner_icmp0;
   clib_bihash_kv_8_8_t kv0, value0;
-  snat_session_t * s0;
+  snat_session_t * s0 = 0;
   u32 new_addr0, old_addr0;
   u16 old_id0, new_id0;
   ip_csum_t sum0;
+  u16 checksum0;
   snat_runtime_t * rt = (snat_runtime_t *)node->runtime_data;
+  u8 is_error_message = 0;
 
-  if (PREDICT_FALSE(icmp0->type != ICMP4_echo_request))
-    {
-      b0->error = node->errors[SNAT_IN2OUT_ERROR_BAD_ICMP_TYPE];
-      return SNAT_IN2OUT_NEXT_DROP;
-    }
-  
   echo0 = (icmp_echo_header_t *)(icmp0+1);
 
   key0.addr = ip0->src_address;
-  key0.port = echo0->identifier;
-  key0.protocol = SNAT_PROTOCOL_ICMP;
   key0.fib_index = rx_fib_index0;
   
+  switch(icmp0->type)
+    {
+    case ICMP4_destination_unreachable:
+    case ICMP4_time_exceeded:
+    case ICMP4_parameter_problem:
+    case ICMP4_source_quench:
+    case ICMP4_redirect:
+    case ICMP4_alternate_host_address:
+      is_error_message = 1;
+    }
+
+  if (!is_error_message)
+    {
+      if (PREDICT_FALSE(icmp0->type != ICMP4_echo_request))
+        {
+          b0->error = node->errors[SNAT_IN2OUT_ERROR_BAD_ICMP_TYPE];
+          next0 = SNAT_IN2OUT_NEXT_DROP;
+          goto out;
+        }
+      key0.protocol = SNAT_PROTOCOL_ICMP;
+      key0.port = echo0->identifier;
+    }
+  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);
+      switch (key0.protocol)
+        {
+        case SNAT_PROTOCOL_ICMP:
+          inner_icmp0 = (icmp46_header_t*)l4_header;
+          inner_echo0 = (icmp_echo_header_t *)(inner_icmp0+1);
+          key0.port = inner_echo0->identifier;
+          break;
+        case SNAT_PROTOCOL_UDP:
+        case SNAT_PROTOCOL_TCP:
+          key0.port = ((tcp_udp_header_t*)l4_header)->dst_port;
+          break;
+        default:
+          b0->error = node->errors[SNAT_IN2OUT_ERROR_UNSUPPORTED_PROTOCOL];
+          next0 = SNAT_IN2OUT_NEXT_DROP;
+          goto out;
+        }
+    }
+
   kv0.key = key0.as_u64;
   
   if (clib_bihash_search_8_8 (&sm->in2out, &kv0, &value0))
     {
-      ip4_address_t * first_int_addr;
+      if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index0, ip0,
+          IP_PROTOCOL_ICMP, rx_fib_index0)))
+        goto out;
 
-      if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index0))
+      if (is_error_message)
         {
-          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;
+          next0 = SNAT_IN2OUT_NEXT_DROP;
+          goto out;
         }
-      
-      /* Don't NAT packet aimed at the intfc address */
-      if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
-                                rt->cached_ip4_address))
-        return next0;
-      
+
       next0 = slow_path (sm, b0, ip0, rx_fib_index0, &key0,
                          &s0, node, next0, cpu_index);
       
       if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
-        return next0;
+        goto out;
     }
   else
     s0 = pool_elt_at_index (sm->per_thread_data[cpu_index].sessions,
                             value0.value);
 
+  sum0 = ip_incremental_checksum (0, icmp0,
+                                  ntohs(ip0->length) - ip4_header_bytes (ip0));
+  checksum0 = ~ip_csum_fold (sum0);
+  if (PREDICT_FALSE(checksum0 != 0 && checksum0 != 0xffff))
+    {
+      next0 = SNAT_IN2OUT_NEXT_DROP;
+      goto out;
+    }
+
   old_addr0 = ip0->src_address.as_u32;
   ip0->src_address = s0->out2in.addr;
   new_addr0 = ip0->src_address.as_u32;
   vnet_buffer(b0)->sw_if_index[VLIB_TX] = s0->out2in.fib_index;
-  
+
   sum0 = ip0->checksum;
-  sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
-                         ip4_header_t,
+  sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
                          src_address /* changed member */);
   ip0->checksum = ip_csum_fold (sum0);
   
-  old_id0 = echo0->identifier;
-  new_id0 = s0->out2in.port;
-  echo0->identifier = new_id0;
+  if (!is_error_message)
+    {
+      old_id0 = echo0->identifier;
+      new_id0 = s0->out2in.port;
+      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);
+      sum0 = icmp0->checksum;
+      sum0 = ip_csum_update (sum0, old_id0, new_id0, icmp_echo_header_t,
+                             identifier);
+      icmp0->checksum = ip_csum_fold (sum0);
+    }
+  else
+    {
+      if (!ip4_header_checksum_is_valid (inner_ip0))
+        {
+          next0 = SNAT_IN2OUT_NEXT_DROP;
+          goto out;
+        }
+
+      old_addr0 = inner_ip0->dst_address.as_u32;
+      inner_ip0->dst_address = s0->out2in.addr;
+      new_addr0 = inner_ip0->src_address.as_u32;
+
+      sum0 = icmp0->checksum;
+      sum0 = ip_csum_update (sum0, old_addr0, new_addr0, ip4_header_t,
+                             dst_address /* changed member */);
+      icmp0->checksum = ip_csum_fold (sum0);
+
+      switch (key0.protocol)
+        {
+          case SNAT_PROTOCOL_ICMP:
+            old_id0 = inner_echo0->identifier;
+            new_id0 = s0->out2in.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 SNAT_PROTOCOL_UDP:
+          case SNAT_PROTOCOL_TCP:
+            old_id0 = ((tcp_udp_header_t*)l4_header)->dst_port;
+            new_id0 = s0->out2in.port;
+            ((tcp_udp_header_t*)l4_header)->dst_port = new_id0;
+
+            sum0 = icmp0->checksum;
+            sum0 = ip_csum_update (sum0, old_id0, new_id0, tcp_udp_header_t,
+                                   dst_port);
+            icmp0->checksum = ip_csum_fold (sum0);
+            break;
+          default:
+            ASSERT(0);
+        }
+    }
 
   /* Accounting */
   s0->last_heard = now;
@@ -405,6 +604,8 @@ static inline u32 icmp_in2out_slow_path (snat_main_t *sm,
                           s0->per_user_index);
     }
 
+out:
+  *p_s0 = s0;
   return next0;
 }
 
@@ -431,7 +632,7 @@ snat_hairpinning (snat_main_t *sm,
                   u32 proto0)
 {
   snat_session_key_t key0, sm0;
-  snat_static_mapping_key_t k0;
+  snat_worker_key_t k0;
   snat_session_t * s0;
   clib_bihash_kv_8_8_t kv0, value0;
   ip_csum_t sum0;
@@ -488,12 +689,12 @@ snat_hairpinning (snat_main_t *sm,
                              ip4_header_t, dst_address);
       ip0->checksum = ip_csum_fold (sum0);
 
-      old_dst_port0 = tcp0->ports.dst;
+      old_dst_port0 = tcp0->dst;
       if (PREDICT_TRUE(new_dst_port0 != old_dst_port0))
         {
           if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
             {
-              tcp0->ports.dst = new_dst_port0;
+              tcp0->dst = new_dst_port0;
               sum0 = tcp0->checksum;
               sum0 = ip_csum_update (sum0, old_dst_addr0, new_dst_addr0,
                                      ip4_header_t, dst_address);
@@ -593,13 +794,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 
           next0 = next1 = SNAT_IN2OUT_NEXT_LOOKUP;
 
-          proto0 = ~0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_UDP) 
-            ? SNAT_PROTOCOL_UDP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_TCP) 
-            ? SNAT_PROTOCOL_TCP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_ICMP) 
-            ? SNAT_PROTOCOL_ICMP : proto0;
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          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_IN2OUT_NEXT_ICMP_ERROR;
+              goto trace00;
+            }
 
           /* Next configured feature, probably ip4-lookup */
           if (is_slow_path)
@@ -611,7 +816,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                 {
                   next0 = icmp_in2out_slow_path 
                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, 
-                     node, next0, now, cpu_index);
+                     node, next0, now, cpu_index, &s0);
                   goto trace00;
                 }
             }
@@ -635,25 +840,10 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  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;
-                    }
-                  
-                  /* Don't NAT packet aimed at the intfc address */
-                  if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
-                                    rt->cached_ip4_address))
+                  if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index0, ip0,
+                      proto0, rx_fib_index0)))
                     goto trace00;
-                  
+
                   next0 = slow_path (sm, b0, ip0, rx_fib_index0, &key0,
                                      &s0, node, next0, cpu_index);
                   if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
@@ -682,9 +872,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 
           if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
             {
-              old_port0 = tcp0->ports.src;
-              tcp0->ports.src = s0->out2in.port;
-              new_port0 = tcp0->ports.src;
+              old_port0 = tcp0->src_port;
+              tcp0->src_port = s0->out2in.port;
+              new_port0 = tcp0->src_port;
 
               sum0 = tcp0->checksum;
               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
@@ -744,13 +934,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
          rx_fib_index1 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index, 
                                    sw_if_index1);
 
-          proto1 = ~0;
-          proto1 = (ip1->protocol == IP_PROTOCOL_UDP) 
-            ? SNAT_PROTOCOL_UDP : proto1;
-          proto1 = (ip1->protocol == IP_PROTOCOL_TCP) 
-            ? SNAT_PROTOCOL_TCP : proto1;
-          proto1 = (ip1->protocol == IP_PROTOCOL_ICMP) 
-            ? SNAT_PROTOCOL_ICMP : proto1;
+          proto1 = ip_proto_to_snat_proto (ip1->protocol);
+
+          if (PREDICT_FALSE(ip0->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);
+              next0 = SNAT_IN2OUT_NEXT_ICMP_ERROR;
+              goto trace01;
+            }
 
           /* Next configured feature, probably ip4-lookup */
           if (is_slow_path)
@@ -762,7 +956,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                 {
                   next1 = icmp_in2out_slow_path 
                     (sm, b1, ip1, icmp1, sw_if_index1, rx_fib_index1, node,
-                     next1, now, cpu_index);
+                     next1, now, cpu_index, &s1);
                   goto trace01;
                 }
             }
@@ -786,25 +980,10 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  ip4_address_t * first_int_addr;
-                  
-                  if (PREDICT_FALSE(rt->cached_sw_if_index != sw_if_index1))
-                    {
-                      first_int_addr = 
-                        ip4_interface_first_address (sm->ip4_main, sw_if_index1,
-                                                     0 /* just want the address */);
-                      rt->cached_sw_if_index = sw_if_index1;
-                      if (first_int_addr)
-                        rt->cached_ip4_address = first_int_addr->as_u32;
-                      else
-                        rt->cached_ip4_address = 0;
-                    }
-                  
-                  /* Don't NAT packet aimed at the intfc address */
-                  if (PREDICT_FALSE(ip1->dst_address.as_u32 ==
-                                    rt->cached_ip4_address))
+                  if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index1, ip1,
+                      proto1, rx_fib_index1)))
                     goto trace01;
-                  
+
                   next1 = slow_path (sm, b1, ip1, rx_fib_index1, &key1,
                                      &s1, node, next1, cpu_index);
                   if (PREDICT_FALSE (next1 == SNAT_IN2OUT_NEXT_DROP))
@@ -833,9 +1012,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 
           if (PREDICT_TRUE(proto1 == SNAT_PROTOCOL_TCP))
             {
-              old_port1 = tcp1->ports.src;
-              tcp1->ports.src = s1->out2in.port;
-              new_port1 = tcp1->ports.src;
+              old_port1 = tcp1->src_port;
+              tcp1->src_port = s1->out2in.port;
+              new_port1 = tcp1->src_port;
 
               sum1 = tcp1->checksum;
               sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
@@ -930,13 +1109,17 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
          rx_fib_index0 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index, 
                                    sw_if_index0);
 
-          proto0 = ~0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_UDP) 
-            ? SNAT_PROTOCOL_UDP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_TCP) 
-            ? SNAT_PROTOCOL_TCP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_ICMP) 
-            ? SNAT_PROTOCOL_ICMP : proto0;
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
+
+          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_IN2OUT_NEXT_ICMP_ERROR;
+              goto trace0;
+            }
 
           /* Next configured feature, probably ip4-lookup */
           if (is_slow_path)
@@ -948,7 +1131,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                 {
                   next0 = icmp_in2out_slow_path 
                     (sm, b0, ip0, icmp0, sw_if_index0, rx_fib_index0, node,
-                     next0, now, cpu_index);
+                     next0, now, cpu_index, &s0);
                   goto trace0;
                 }
             }
@@ -972,27 +1155,13 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  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;
-                    }
-                  
-                  /* Don't NAT packet aimed at the intfc address */
-                  if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
-                                    rt->cached_ip4_address))
+                  if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index0, ip0,
+                      proto0, rx_fib_index0)))
                     goto trace0;
-                  
+
                   next0 = slow_path (sm, b0, ip0, rx_fib_index0, &key0,
                                      &s0, node, next0, cpu_index);
+
                   if (PREDICT_FALSE (next0 == SNAT_IN2OUT_NEXT_DROP))
                     goto trace0;
                 }
@@ -1019,9 +1188,9 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
 
           if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
             {
-              old_port0 = tcp0->ports.src;
-              tcp0->ports.src = s0->out2in.port;
-              new_port0 = tcp0->ports.src;
+              old_port0 = tcp0->src_port;
+              tcp0->src_port = s0->out2in.port;
+              new_port0 = tcp0->src_port;
 
               sum0 = tcp0->checksum;
               sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
@@ -1114,6 +1283,7 @@ VLIB_REGISTER_NODE (snat_in2out_node) = {
     [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
     [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_IN2OUT_NEXT_SLOW_PATH] = "snat-in2out-slowpath",
+    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
   },
 };
 
@@ -1146,6 +1316,7 @@ VLIB_REGISTER_NODE (snat_in2out_slowpath_node) = {
     [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
     [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_IN2OUT_NEXT_SLOW_PATH] = "snat-in2out-slowpath",
+    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
   },
 };
 
@@ -1215,8 +1386,12 @@ snat_in2out_worker_handoff_fn (vlib_main_t * vm,
       if (clib_bihash_search_8_8 (&sm->worker_by_in, &kv0, &value0))
         {
           /* No, assign next available worker (RR) */
-          next_worker_index = sm->first_worker_index +
-            sm->workers[sm->next_worker++ % vec_len (sm->workers)];
+          next_worker_index = sm->first_worker_index;
+          if (vec_len (sm->workers))
+            {
+              next_worker_index += 
+                sm->workers[sm->next_worker++ % _vec_len (sm->workers)];
+            }
 
           /* add non-traslated packets worker lookup */
           kv0.value = next_worker_index;
@@ -1354,23 +1529,8 @@ static inline u32 icmp_in2out_static_map (snat_main_t *sm,
   
   if (snat_static_mapping_match(sm, key0, &sm0, 0))
     {
-      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;
-        }
-
-      /* Don't NAT packet aimed at the intfc address */
-      if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
-                                rt->cached_ip4_address))
+      if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index0, ip0,
+          IP_PROTOCOL_ICMP, rx_fib_index0)))
         return next0;
 
       b0->error = node->errors[SNAT_IN2OUT_ERROR_NO_TRANSLATION];
@@ -1464,33 +1624,15 @@ snat_in2out_fast_static_map_fn (vlib_main_t * vm,
           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);
 
-          proto0 = ~0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_UDP)
-            ? SNAT_PROTOCOL_UDP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_TCP)
-            ? SNAT_PROTOCOL_TCP : proto0;
-          proto0 = (ip0->protocol == IP_PROTOCOL_ICMP)
-            ? SNAT_PROTOCOL_ICMP : proto0;
+          proto0 = ip_proto_to_snat_proto (ip0->protocol);
 
           if (PREDICT_FALSE (proto0 == ~0))
               goto trace0;
 
           if (PREDICT_FALSE (proto0 == SNAT_PROTOCOL_ICMP))
             {
-              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;
-                  rt->cached_ip4_address = first_int_addr->as_u32;
-                }
-              
-              /* Don't NAT packet aimed at the intfc address */
-              if (PREDICT_FALSE(ip0->dst_address.as_u32 ==
-                                rt->cached_ip4_address))
+              if (PREDICT_FALSE(snat_not_translate(sm, rt, sw_if_index0, ip0,
+                  proto0, rx_fib_index0)))
                 goto trace0;
 
               next0 = icmp_in2out_static_map
@@ -1525,8 +1667,8 @@ snat_in2out_fast_static_map_fn (vlib_main_t * vm,
             {
               if (PREDICT_TRUE(proto0 == SNAT_PROTOCOL_TCP))
                 {
-                  old_port0 = tcp0->ports.src;
-                  tcp0->ports.src = new_port0;
+                  old_port0 = tcp0->src_port;
+                  tcp0->src_port = new_port0;
 
                   sum0 = tcp0->checksum;
                   sum0 = ip_csum_update (sum0, old_addr0, new_addr0,
@@ -1606,6 +1748,7 @@ VLIB_REGISTER_NODE (snat_in2out_fast_node) = {
     [SNAT_IN2OUT_NEXT_DROP] = "error-drop",
     [SNAT_IN2OUT_NEXT_LOOKUP] = "ip4-lookup",
     [SNAT_IN2OUT_NEXT_SLOW_PATH] = "snat-in2out-slowpath",
+    [SNAT_IN2OUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
   },
 };