Simple ip4 NAT plugin

Change-Id: Iffe77bf2a05ced41474540ff54a842101aad7c41
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 601 insertions, 0 deletions

diff --git a/plugins/snat-plugin/snat/out2in.c b/plugins/snat-plugin/snat/out2in.c
new file mode 100644
index 00000000000..0fa96c97f83
--- /dev/null
+++ b/plugins/snat-plugin/snat/out2in.c
@@ -0,0 +1,601 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+
+#include <vnet/ip/ip.h>
+#include <vnet/ethernet/ethernet.h>
+#include <snat/snat.h>
+
+#include <vppinfra/hash.h>
+#include <vppinfra/error.h>
+#include <vppinfra/elog.h>
+
+vlib_node_registration_t snat_out2in_node;
+
+typedef struct {
+  u32 sw_if_index;
+  u32 next_index;
+  u32 session_index;
+} snat_out2in_trace_t;
+
+/* packet trace format function */
+static u8 * format_snat_out2in_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  snat_out2in_trace_t * t = va_arg (*args, snat_out2in_trace_t *);
+  
+  s = format (s, "SNAT_OUT2IN: sw_if_index %d, next index %d, session index %d",
+              t->sw_if_index, t->next_index, t->session_index);
+  return s;
+}
+
+vlib_node_registration_t snat_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")            \
+_(NO_TRANSLATION, "No translation")
+  
+typedef enum {
+#define _(sym,str) SNAT_OUT2IN_ERROR_##sym,
+  foreach_snat_out2in_error
+#undef _
+  SNAT_OUT2IN_N_ERROR,
+} snat_out2in_error_t;
+
+static char * snat_out2in_error_strings[] = {
+#define _(sym,string) string,
+  foreach_snat_out2in_error
+#undef _
+};
+
+typedef enum {
+  SNAT_OUT2IN_NEXT_DROP,
+  SNAT_OUT2IN_N_NEXT,
+} snat_out2in_next_t;
+
+static inline u32 icmp_out2in_slow_path (snat_main_t *sm,
+                                         vlib_buffer_t * b0,
+                                         ip4_header_t * ip0,
+                                         icmp46_header_t * icmp0,
+                                         u32 sw_if_index0,
+                                         u32 rx_fib_index0,
+                                         vlib_node_runtime_t * node,
+                                         u32 next0, f64 now)
+{
+  snat_session_key_t key0;
+  icmp_echo_header_t *echo0;
+  clib_bihash_kv_8_8_t kv0, value0;
+  snat_session_t * s0;
+  u32 new_addr0, old_addr0;
+  u16 old_id0, new_id0;
+  ip_csum_t sum0;
+  snat_runtime_t * rt = (snat_runtime_t *)node->runtime_data;
+
+  echo0 = (icmp_echo_header_t *)(icmp0+1);
+
+  key0.addr = ip0->dst_address;
+  key0.port = echo0->identifier;
+  key0.protocol = SNAT_PROTOCOL_ICMP;
+  key0.fib_index = rx_fib_index0;
+  
+  kv0.key = key0.as_u64;
+  
+  if (clib_bihash_search_8_8 (&sm->out2in, &kv0, &value0))
+    {
+      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))
+        return next0;
+
+      b0->error = node->errors[SNAT_OUT2IN_ERROR_NO_TRANSLATION];
+      return SNAT_OUT2IN_NEXT_DROP;
+    }
+  else
+    s0 = pool_elt_at_index (sm->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);
+  
+  old_id0 = echo0->identifier;
+  new_id0 = s0->in2out.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);
+
+  /* Accounting, per-user LRU list maintenance */
+  s0->last_heard = now;
+  s0->total_pkts++;
+  s0->total_bytes += vlib_buffer_length_in_chain (sm->vlib_main, b0);
+  clib_dlist_remove (sm->list_pool, s0->per_user_index);
+  clib_dlist_addtail (sm->list_pool, s0->per_user_list_head_index,
+                      s0->per_user_index);
+
+  return next0;
+}
+
+static uword
+snat_out2in_node_fn (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;
+  ip_lookup_main_t * lm = sm->ip4_lookup_main;
+  ip_config_main_t * cm = &lm->rx_config_mains[VNET_UNICAST];
+  f64 now = vlib_time_now (vm);
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  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 >= 4 && n_left_to_next >= 2)
+	{
+          u32 bi0, bi1;
+	  vlib_buffer_t * b0, * b1;
+          u32 next0 = SNAT_OUT2IN_NEXT_DROP;
+          u32 next1 = SNAT_OUT2IN_NEXT_DROP;
+          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;
+          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;
+          
+	  /* 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);
+            
+          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);
+
+	  vnet_get_config_data (&cm->config_main,
+                                &b0->current_config_index,
+                                &next0,
+                                0 /* sizeof config data */);
+          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;
+
+          if (PREDICT_FALSE (proto0 == ~0))
+              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);
+              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 (&sm->out2in, &kv0, &value0))
+            goto trace0;
+          else
+            s0 = pool_elt_at_index (sm->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->out2in.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))
+            {
+              old_port0 = tcp0->ports.dst;
+              tcp0->ports.dst = s0->in2out.port;
+              new_port0 = tcp0->ports.dst;
+
+              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, per-user LRU list maintenance */
+          s0->last_heard = now;
+          s0->total_pkts++;
+          s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
+          clib_dlist_remove (sm->list_pool, s0->per_user_index);
+          clib_dlist_addtail (sm->list_pool, s0->per_user_list_head_index,
+                              s0->per_user_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->sessions;
+            }
+
+          pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
+
+
+          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);
+
+	  vnet_get_config_data (&cm->config_main,
+                                &b1->current_config_index,
+                                &next1,
+                                0 /* sizeof config data */);
+          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;
+
+          if (PREDICT_FALSE (proto1 == ~0))
+              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);
+              goto trace1;
+            }
+
+          key1.addr = ip1->dst_address;
+          key1.port = udp1->dst_port;
+          key1.protocol = proto1;
+          key1.fib_index = rx_fib_index1;
+          
+          kv1.key = key1.as_u64;
+
+          if (clib_bihash_search_8_8 (&sm->out2in, &kv1, &value1))
+            goto trace1;
+          else
+            s1 = pool_elt_at_index (sm->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->out2in.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))
+            {
+              old_port1 = tcp1->ports.dst;
+              tcp1->ports.dst = s1->in2out.port;
+              new_port1 = tcp1->ports.dst;
+
+              sum1 = tcp1->checksum;
+              sum1 = ip_csum_update (sum1, old_addr1, new_addr1,
+                                     ip4_header_t,
+                                     dst_address /* changed member */);
+
+              sum1 = ip_csum_update (sum1, old_port1, new_port1,
+                                     ip4_header_t /* cheat */,
+                                     length /* changed member */);
+              tcp1->checksum = ip_csum_fold(sum1);
+            }
+          else
+            {
+              old_port1 = udp1->dst_port;
+              udp1->dst_port = s1->in2out.port;
+              udp1->checksum = 0;
+            }
+
+          /* Accounting, per-user LRU list maintenance */
+          s1->last_heard = now;
+          s1->total_pkts++;
+          s1->total_bytes += vlib_buffer_length_in_chain (vm, b1);
+          clib_dlist_remove (sm->list_pool, s1->per_user_index);
+          clib_dlist_addtail (sm->list_pool, s1->per_user_list_head_index,
+                              s1->per_user_index);
+        trace1:
+
+          if (PREDICT_FALSE((node->flags & VLIB_NODE_FLAG_TRACE) 
+                            && (b1->flags & VLIB_BUFFER_IS_TRACED))) 
+            {
+              snat_out2in_trace_t *t = 
+                 vlib_add_trace (vm, node, b1, sizeof (*t));
+              t->sw_if_index = sw_if_index1;
+              t->next_index = next1;
+              t->session_index = ~0;
+              if (s1)
+                  t->session_index = s1 - sm->sessions;
+            }
+
+          pkts_processed += next0 != SNAT_OUT2IN_NEXT_DROP;
+          pkts_processed += next1 != SNAT_OUT2IN_NEXT_DROP;
+
+          /* 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);
+        }
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+          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;
+          u32 rx_fib_index0;
+          u32 proto0;
+          snat_session_t * s0 = 0;
+          clib_bihash_kv_8_8_t kv0, value0;
+          
+          /* 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 = vec_elt (sm->ip4_main->fib_index_by_sw_if_index, 
+                                   sw_if_index0);
+
+	  vnet_get_config_data (&cm->config_main,
+                                &b0->current_config_index,
+                                &next0,
+                                0 /* sizeof config data */);
+          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;
+
+          if (PREDICT_FALSE (proto0 == ~0))
+              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);
+              goto trace00;
+            }
+
+          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 (&sm->out2in, &kv0, &value0))
+            goto trace00;
+          else
+            s0 = pool_elt_at_index (sm->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->out2in.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))
+            {
+              old_port0 = tcp0->ports.dst;
+              tcp0->ports.dst = s0->in2out.port;
+              new_port0 = tcp0->ports.dst;
+
+              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, per-user LRU list maintenance */
+          s0->last_heard = now;
+          s0->total_pkts++;
+          s0->total_bytes += vlib_buffer_length_in_chain (vm, b0);
+          clib_dlist_remove (sm->list_pool, s0->per_user_index);
+          clib_dlist_addtail (sm->list_pool, s0->per_user_list_head_index,
+                              s0->per_user_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->sessions;
+            }
+
+          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);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  vlib_node_increment_counter (vm, snat_out2in_node.index, 
+                               SNAT_OUT2IN_ERROR_OUT2IN_PACKETS, 
+                               pkts_processed);
+  return frame->n_vectors;
+}
+
+VLIB_REGISTER_NODE (snat_out2in_node) = {
+  .function = snat_out2in_node_fn,
+  .name = "snat-out2in",
+  .vector_size = sizeof (u32),
+  .format_trace = format_snat_out2in_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  
+  .n_errors = ARRAY_LEN(snat_out2in_error_strings),
+  .error_strings = snat_out2in_error_strings,
+
+  .runtime_data_bytes = sizeof (snat_runtime_t),
+  
+  .n_next_nodes = SNAT_OUT2IN_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [SNAT_OUT2IN_NEXT_DROP] = "error-drop",
+  },
+};
+VLIB_NODE_FUNCTION_MULTIARCH (snat_out2in_node, snat_out2in_node_fn);