Simple ip4 NAT plugin

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

1 files changed, 716 insertions, 0 deletions

diff --git a/plugins/snat-plugin/snat/snat.c b/plugins/snat-plugin/snat/snat.c
new file mode 100644
index 00000000000..3675602e917
--- /dev/null
+++ b/plugins/snat-plugin/snat/snat.c
@@ -0,0 +1,716 @@
+/*
+ * snat.c - simple nat plugin
+ *
+ * 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 <vnet/vnet.h>
+#include <vnet/plugin/plugin.h>
+#include <vlibapi/api.h>
+#include <snat/snat.h>
+
+#include <vlibapi/api.h>
+#include <vlibmemory/api.h>
+#include <vlibsocket/api.h>
+
+snat_main_t snat_main;
+
+/* define message IDs */
+#include <snat/snat_msg_enum.h>
+
+/* define message structures */
+#define vl_typedefs
+#include <snat/snat_all_api_h.h> 
+#undef vl_typedefs
+
+/* define generated endian-swappers */
+#define vl_endianfun
+#include <snat/snat_all_api_h.h> 
+#undef vl_endianfun
+
+#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
+
+/* Get the API version number */
+#define vl_api_version(n,v) static u32 api_version=(v);
+#include <snat/snat_all_api_h.h>
+#undef vl_api_version
+
+/* Macro to finish up custom dump fns */
+#define FINISH                                  \
+    vec_add1 (s, 0);                            \
+    vl_print (handle, (char *)s);               \
+    vec_free (s);                               \
+    return handle;
+
+/* 
+ * A handy macro to set up a message reply.
+ * Assumes that the following variables are available:
+ * mp - pointer to request message
+ * rmp - pointer to reply message type
+ * rv - return value
+ */
+
+#define REPLY_MACRO(t)                                          \
+do {                                                            \
+    unix_shared_memory_queue_t * q =                            \
+    vl_api_client_index_to_input_queue (mp->client_index);      \
+    if (!q)                                                     \
+        return;                                                 \
+                                                                \
+    rmp = vl_msg_api_alloc (sizeof (*rmp));                     \
+    rmp->_vl_msg_id = ntohs((t)+sm->msg_id_base);               \
+    rmp->context = mp->context;                                 \
+    rmp->retval = ntohl(rv);                                    \
+                                                                \
+    vl_msg_api_send_shmem (q, (u8 *)&rmp);                      \
+} while(0);
+
+
+/* Hook up input features */
+VNET_IP4_UNICAST_FEATURE_INIT (ip4_snat_in2out, static) = {
+  .node_name = "snat-in2out",
+  .runs_before = {"snat-out2in", 0},
+  .feature_index = &snat_main.rx_feature_in2out,
+};
+VNET_IP4_UNICAST_FEATURE_INIT (ip4_snat_out2in, static) = {
+  .node_name = "snat-out2in",
+  .runs_before = {"ip4-lookup", 0},
+  .feature_index = &snat_main.rx_feature_out2in,
+};
+
+/* 
+ * This routine exists to convince the vlib plugin framework that
+ * we haven't accidentally copied a random .dll into the plugin directory.
+ *
+ * Also collects global variable pointers passed from the vpp engine
+ */
+
+clib_error_t * 
+vlib_plugin_register (vlib_main_t * vm, vnet_plugin_handoff_t * h,
+                      int from_early_init)
+{
+  snat_main_t * sm = &snat_main;
+  clib_error_t * error = 0;
+
+  sm->vlib_main = vm;
+  sm->vnet_main = h->vnet_main;
+  sm->ethernet_main = h->ethernet_main;
+
+  return error;
+}
+
+/*$$$$$ move to an installed header file */
+#if (1 || CLIB_DEBUG > 0)       /* "trust, but verify" */
+
+#define VALIDATE_SW_IF_INDEX(mp)				\
+ do { u32 __sw_if_index = ntohl(mp->sw_if_index);		\
+    vnet_main_t *__vnm = vnet_get_main();                       \
+    if (pool_is_free_index(__vnm->interface_main.sw_interfaces, \
+                           __sw_if_index)) {                    \
+        rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;                \
+        goto bad_sw_if_index;                                   \
+    }                                                           \
+} while(0);
+
+#define BAD_SW_IF_INDEX_LABEL                   \
+do {                                            \
+bad_sw_if_index:                                \
+    ;                                           \
+} while (0);
+
+#define VALIDATE_RX_SW_IF_INDEX(mp)				\
+ do { u32 __rx_sw_if_index = ntohl(mp->rx_sw_if_index);		\
+    vnet_main_t *__vnm = vnet_get_main();                       \
+    if (pool_is_free_index(__vnm->interface_main.sw_interfaces, \
+                           __rx_sw_if_index)) {			\
+        rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;                \
+        goto bad_rx_sw_if_index;				\
+    }                                                           \
+} while(0);
+
+#define BAD_RX_SW_IF_INDEX_LABEL		\
+do {                                            \
+bad_rx_sw_if_index:				\
+    ;                                           \
+} while (0);
+
+#define VALIDATE_TX_SW_IF_INDEX(mp)				\
+ do { u32 __tx_sw_if_index = ntohl(mp->tx_sw_if_index);		\
+    vnet_main_t *__vnm = vnet_get_main();                       \
+    if (pool_is_free_index(__vnm->interface_main.sw_interfaces, \
+                           __tx_sw_if_index)) {			\
+        rv = VNET_API_ERROR_INVALID_SW_IF_INDEX;                \
+        goto bad_tx_sw_if_index;				\
+    }                                                           \
+} while(0);
+
+#define BAD_TX_SW_IF_INDEX_LABEL		\
+do {                                            \
+bad_tx_sw_if_index:				\
+    ;                                           \
+} while (0);
+
+#else
+
+#define VALIDATE_SW_IF_INDEX(mp)
+#define BAD_SW_IF_INDEX_LABEL
+#define VALIDATE_RX_SW_IF_INDEX(mp)
+#define BAD_RX_SW_IF_INDEX_LABEL
+#define VALIDATE_TX_SW_IF_INDEX(mp)
+#define BAD_TX_SW_IF_INDEX_LABEL
+
+#endif  /* CLIB_DEBUG > 0 */
+
+void snat_add_address (snat_main_t *sm, ip4_address_t *addr)
+{
+  snat_address_t * ap;
+
+  vec_add2 (sm->addresses, ap, 1);
+  ap->addr = *addr;
+
+}
+
+static void increment_v4_address (ip4_address_t * a)
+{
+  u32 v;
+  
+  v = clib_net_to_host_u32(a->as_u32) + 1;
+  a->as_u32 = clib_host_to_net_u32(v);
+}
+
+static void 
+vl_api_snat_add_address_range_t_handler
+(vl_api_snat_add_address_range_t * mp)
+{
+  snat_main_t * sm = &snat_main;
+  vl_api_snat_add_address_range_reply_t * rmp;
+  ip4_address_t this_addr;
+  u32 start_host_order, end_host_order;
+  int i, count;
+  int rv = 0;
+  u32 * tmp;
+
+  if (mp->is_ip4 != 1)
+    {
+      rv = VNET_API_ERROR_UNIMPLEMENTED;
+      goto send_reply;
+    }
+
+  tmp = (u32 *) mp->first_ip_address;
+  start_host_order = clib_host_to_net_u32 (tmp[0]);
+  tmp = (u32 *) mp->last_ip_address;
+  end_host_order = clib_host_to_net_u32 (tmp[0]);
+
+  count = (end_host_order - start_host_order) + 1;
+
+  if (count > 1024)
+    clib_warning ("%U - %U, %d addresses...",
+                  format_ip4_address, mp->first_ip_address,
+                  format_ip4_address, mp->last_ip_address,
+                  count);
+  
+  memcpy (&this_addr.as_u8, mp->first_ip_address, 4);
+
+  for (i = 0; i < count; i++)
+    {
+      snat_add_address (sm, &this_addr);
+      increment_v4_address (&this_addr);
+    }
+
+ send_reply:
+  REPLY_MACRO (VL_API_SNAT_ADD_ADDRESS_RANGE_REPLY);
+}
+
+static void *vl_api_snat_add_address_range_t_print
+(vl_api_snat_add_address_range_t *mp, void * handle)
+{
+  u8 * s;
+
+  s = format (0, "SCRIPT: snat_add_address_range ");
+  s = format (s, "%U ", format_ip4_address, mp->first_ip_address);
+  if (memcmp (mp->first_ip_address, mp->last_ip_address, 4))
+    {
+      s = format (s, " - %U ", format_ip4_address, mp->last_ip_address);
+    }
+  FINISH;
+}
+
+static void
+vl_api_snat_interface_add_del_feature_t_handler
+(vl_api_snat_interface_add_del_feature_t * mp)
+{
+  snat_main_t * sm = &snat_main;
+  vl_api_snat_interface_add_del_feature_reply_t * rmp;
+  u8 is_del = mp->is_add == 0;
+  u32 sw_if_index = ntohl(mp->sw_if_index);
+  u32 ci;
+  ip4_main_t * im = &ip4_main;
+  ip_lookup_main_t * lm = &im->lookup_main;
+  ip_config_main_t * rx_cm = &lm->rx_config_mains[VNET_UNICAST];
+  u32 feature_index;
+  int rv = 0;
+
+  VALIDATE_SW_IF_INDEX(mp);
+
+  feature_index = mp->is_inside ? sm->rx_feature_in2out
+    : sm->rx_feature_out2in;
+
+  ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
+  ci = (is_del
+        ? vnet_config_del_feature
+        : vnet_config_add_feature)
+    (sm->vlib_main, &rx_cm->config_main,
+     ci,
+     feature_index,
+     0 /* config struct */, 
+     0 /* sizeof config struct*/);
+  rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
+  
+  BAD_SW_IF_INDEX_LABEL;
+
+  REPLY_MACRO(VL_API_SNAT_INTERFACE_ADD_DEL_FEATURE_REPLY);
+}
+
+static void *vl_api_snat_interface_add_del_feature_t_print
+(vl_api_snat_interface_add_del_feature_t * mp, void *handle)
+{
+  u8 * s;
+
+  s = format (0, "SCRIPT: snat_interface_add_del_feature ");
+  s = format (s, "sw_if_index %d %s %s",
+              clib_host_to_net_u32(mp->sw_if_index),
+              mp->is_inside ? "in":"out",
+              mp->is_add ? "" : "del");
+
+  FINISH;
+}
+
+/* List of message types that this plugin understands */
+#define foreach_snat_plugin_api_msg                                     \
+_(SNAT_ADD_ADDRESS_RANGE, snat_add_address_range)                       \
+_(SNAT_INTERFACE_ADD_DEL_FEATURE, snat_interface_add_del_feature)
+
+/* Set up the API message handling tables */
+static clib_error_t *
+snat_plugin_api_hookup (vlib_main_t *vm)
+{
+   snat_main_t * sm __attribute__ ((unused)) = &snat_main;
+#define _(N,n)                                                  \
+    vl_msg_api_set_handlers((VL_API_##N + sm->msg_id_base),     \
+                           #n,					\
+                           vl_api_##n##_t_handler,              \
+                           vl_noop_handler,                     \
+                           vl_api_##n##_t_endian,               \
+                           vl_api_##n##_t_print,                \
+                           sizeof(vl_api_##n##_t), 1); 
+    foreach_snat_plugin_api_msg;
+#undef _
+
+    return 0;
+}
+
+static void plugin_custom_dump_configure (snat_main_t * sm) 
+{
+#define _(n,f) sm->api_main->msg_print_handlers \
+  [VL_API_##n + sm->msg_id_base]                \
+    = (void *) vl_api_##f##_t_print;
+  foreach_snat_plugin_api_msg;
+#undef _
+}
+
+static clib_error_t * snat_init (vlib_main_t * vm)
+{
+  snat_main_t * sm = &snat_main;
+  clib_error_t * error = 0;
+  ip4_main_t * im = &ip4_main;
+  ip_lookup_main_t * lm = &im->lookup_main;
+  u8 * name;
+
+  name = format (0, "snat_%08x%c", api_version, 0);
+
+  /* Ask for a correctly-sized block of API message decode slots */
+  sm->msg_id_base = vl_msg_api_get_msg_ids 
+      ((char *) name, VL_MSG_FIRST_AVAILABLE);
+
+  sm->vlib_main = vm;
+  sm->vnet_main = vnet_get_main();
+  sm->ip4_main = im;
+  sm->ip4_lookup_main = lm;
+  sm->api_main = &api_main;
+
+  error = snat_plugin_api_hookup (vm);
+  plugin_custom_dump_configure (sm);
+  vec_free(name);
+
+  return error;
+}
+
+VLIB_INIT_FUNCTION (snat_init);
+
+void snat_free_outside_address_and_port (snat_main_t * sm, 
+                                         snat_session_key_t * k, 
+                                         u32 address_index)
+{
+  snat_address_t *a;
+  u16 port_host_byte_order = clib_net_to_host_u16 (k->port);
+  
+  ASSERT (address_index < vec_len (sm->addresses));
+
+  a = sm->addresses + address_index;
+
+  ASSERT (clib_bitmap_get (a->busy_port_bitmap, port_host_byte_order) == 1);
+
+  a->busy_port_bitmap = clib_bitmap_set (a->busy_port_bitmap, 
+                                         port_host_byte_order, 0);
+  a->busy_ports--;
+}  
+
+int snat_alloc_outside_address_and_port (snat_main_t * sm, 
+                                         snat_session_key_t * k,
+                                         u32 * address_indexp)
+{
+  int i;
+  snat_address_t *a;
+  u32 portnum;
+
+  for (i = 0; i < vec_len (sm->addresses); i++)
+    {
+      if (sm->addresses[i].busy_ports < (65535-1024))
+        {
+          a = sm->addresses + i;
+
+          while (1)
+            {
+              portnum = random_u32 (&sm->random_seed);
+              portnum &= 0xFFFF;
+              if (portnum < 1024)
+                continue;
+              if (clib_bitmap_get (a->busy_port_bitmap, portnum))
+                continue;
+              a->busy_port_bitmap = clib_bitmap_set (a->busy_port_bitmap,
+                                                     portnum, 1);
+              a->busy_ports++;
+              /* Caller sets protocol and fib index */
+              k->addr = a->addr;
+              k->port = clib_host_to_net_u16(portnum);
+              *address_indexp = i;
+              return 0;
+            }
+        }
+    }
+  /* Totally out of translations to use... */
+  return 1;
+}
+
+
+static clib_error_t *
+add_address_command_fn (vlib_main_t * vm,
+                        unformat_input_t * input,
+                        vlib_cli_command_t * cmd)
+{
+  snat_main_t * sm = &snat_main;
+  ip4_address_t start_addr, end_addr, this_addr;
+  u32 start_host_order, end_host_order;
+  int i, count;
+
+  if (unformat (input, "%U - %U", 
+                unformat_ip4_address, &start_addr,
+                unformat_ip4_address, &end_addr))
+    ;
+  else if (unformat (input, "%U", unformat_ip4_address, &start_addr))
+    end_addr = start_addr;
+
+  start_host_order = clib_host_to_net_u32 (start_addr.as_u32);
+  end_host_order = clib_host_to_net_u32 (end_addr.as_u32);
+  
+  if (end_host_order < start_host_order)
+    return clib_error_return (0, "end address less than start address");
+
+  count = (end_host_order - start_host_order) + 1;
+
+  if (count > 1024)
+    clib_warning ("%U - %U, %d addresses...",
+                  format_ip4_address, &start_addr,
+                  format_ip4_address, &end_addr,
+                  count);
+  
+  this_addr = start_addr;
+
+  for (i = 0; i < count; i++)
+    {
+      snat_add_address (sm, &this_addr);
+      increment_v4_address (&this_addr);
+    }
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (add_address_command, static) = {
+  .path = "snat add address",
+  .short_help = "snat add addresses <ip4-range-start> [- <ip4-range-end>]",
+  .function = add_address_command_fn,
+};
+
+static clib_error_t *
+snat_feature_command_fn (vlib_main_t * vm,
+                          unformat_input_t * input,
+                          vlib_cli_command_t * cmd)
+{
+  vnet_main_t * vnm = vnet_get_main();
+  snat_main_t * sm = &snat_main;
+  ip4_main_t * im = &ip4_main;
+  ip_lookup_main_t * lm = &im->lookup_main;
+  ip_config_main_t * rx_cm = &lm->rx_config_mains[VNET_UNICAST];
+  clib_error_t * error = 0;
+  u32 sw_if_index, ci;
+  u32 feature_index;
+  u32 * inside_sw_if_indices = 0;
+  u32 * outside_sw_if_indices = 0;
+  int is_del = 0;
+  int i;
+
+  sw_if_index = ~0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "in %U", unformat_vnet_sw_interface, 
+                    vnm, &sw_if_index))
+        vec_add1 (inside_sw_if_indices, sw_if_index);
+      else if (unformat (input, "out %U", unformat_vnet_sw_interface, 
+                         vnm, &sw_if_index))
+        vec_add1 (outside_sw_if_indices, sw_if_index);
+      else if (unformat (input, "del"))
+        is_del = 1;
+      else
+        break;
+    }
+
+  if (vec_len (inside_sw_if_indices))
+    {
+      feature_index = sm->rx_feature_in2out;
+
+      for (i = 0; i < vec_len(inside_sw_if_indices); i++)
+        {
+          sw_if_index = inside_sw_if_indices[i];
+          ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
+          ci = (is_del
+                ? vnet_config_del_feature
+                : vnet_config_add_feature)
+            (vm, &rx_cm->config_main,
+             ci,
+             feature_index,
+             0 /* config struct */, 
+             0 /* sizeof config struct*/);
+          rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
+        }
+    }
+
+  if (vec_len (outside_sw_if_indices))
+    {
+      feature_index = sm->rx_feature_out2in;
+
+      for (i = 0; i < vec_len(outside_sw_if_indices); i++)
+        {
+          sw_if_index = outside_sw_if_indices[i];
+          ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
+          ci = (is_del
+                ? vnet_config_del_feature
+                : vnet_config_add_feature)
+            (vm, &rx_cm->config_main,
+             ci,
+             feature_index,
+             0 /* config struct */, 
+             0 /* sizeof config struct*/);
+          rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
+        }
+    }
+
+  vec_free (inside_sw_if_indices);
+  vec_free (outside_sw_if_indices);
+
+  return error;
+}
+
+VLIB_CLI_COMMAND (set_interface_snat_command, static) = {
+  .path = "set interface snat",
+  .function = snat_feature_command_fn,
+  .short_help = "set interface snat in <intfc> out <intfc> [del]",
+};
+
+static clib_error_t *
+snat_config (vlib_main_t * vm, unformat_input_t * input)
+{
+  snat_main_t * sm = &snat_main;
+  u32 translation_buckets = 1024;
+  u32 translation_memory_size = 128<<20;
+  u32 user_buckets = 128;
+  u32 user_memory_size = 64<<20;
+  u32 max_translations_per_user = 100;
+  u32 outside_vrf_id = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "translation hash buckets %d", &translation_buckets))
+        ;
+      else if (unformat (input, "translation hash memory %d",
+                         &translation_memory_size));
+      else if (unformat (input, "user hash buckets %d", &user_buckets))
+        ;
+      else if (unformat (input, "user hash memory %d",
+                         &user_memory_size))
+        ;
+      else if (unformat (input, "max translations per user %d",
+                         &max_translations_per_user))
+        ;
+      else if (unformat (input, "outside VRF id %d",
+                         &outside_vrf_id))
+        ;
+      else 
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+
+  /* for show commands, etc. */
+  sm->translation_buckets = translation_buckets;
+  sm->translation_memory_size = translation_memory_size;
+  sm->user_buckets = user_buckets;
+  sm->user_memory_size = user_memory_size;
+  sm->max_translations_per_user = max_translations_per_user;
+  sm->outside_vrf_id = outside_vrf_id;
+
+  clib_bihash_init_8_8 (&sm->in2out, "in2out", translation_buckets,
+                        translation_memory_size);
+  
+  clib_bihash_init_8_8 (&sm->out2in, "out2in", translation_buckets,
+                        translation_memory_size);
+
+  clib_bihash_init_8_8 (&sm->user_hash, "users", user_buckets,
+                        user_memory_size);
+  return 0;
+}
+
+VLIB_CONFIG_FUNCTION (snat_config, "snat");
+
+u8 * format_snat_key (u8 * s, va_list * args)
+{
+  snat_session_key_t * key = va_arg (*args, snat_session_key_t *);
+  char * protocol_string = "unknown";
+  static char *protocol_strings[] = {
+      "UDP",
+      "TCP",
+      "ICMP",
+  };
+
+  if (key->protocol < ARRAY_LEN(protocol_strings))
+      protocol_string = protocol_strings[key->protocol];
+
+  s = format (s, "%U proto %s port %d fib %d",
+              format_ip4_address, &key->addr, protocol_string,
+              key->port, key->fib_index);
+  return s;
+}
+
+u8 * format_snat_session (u8 * s, va_list * args)
+{
+  snat_main_t * sm __attribute__((unused)) = va_arg (*args, snat_main_t *);
+  snat_session_t * sess = va_arg (*args, snat_session_t *);
+
+  s = format (s, "  i2o %U\n", format_snat_key, &sess->in2out);
+  s = format (s, "    o2i %U\n", format_snat_key, &sess->out2in);
+  s = format (s, "       last heard %.2f\n", sess->last_heard);
+  s = format (s, "       total pkts %d, total bytes %lld\n",
+              sess->total_pkts, sess->total_bytes);
+
+  return s;
+}
+
+u8 * format_snat_user (u8 * s, va_list * args)
+{
+  snat_main_t * sm = va_arg (*args, snat_main_t *);
+  snat_user_t * u = va_arg (*args, snat_user_t *);
+  int verbose = va_arg (*args, int);
+  dlist_elt_t * head, * elt;
+  u32 elt_index, head_index;
+  u32 session_index;
+  snat_session_t * sess;
+
+  s = format (s, "%U: %d translations\n",
+              format_ip4_address, &u->addr, u->nsessions);
+
+  if (verbose == 0)
+    return s;
+
+  head_index = u->sessions_per_user_list_head_index;
+  head = pool_elt_at_index (sm->list_pool, head_index);
+
+  elt_index = head->next;
+  elt = pool_elt_at_index (sm->list_pool, elt_index);
+  session_index = elt->value;
+
+  while (session_index != ~0)
+    {
+      sess = pool_elt_at_index (sm->sessions, session_index);
+
+      s = format (s, "  %U\n", format_snat_session, sm, sess);
+
+      elt_index = elt->next;
+      elt = pool_elt_at_index (sm->list_pool, elt_index);
+      session_index = elt->value;
+    }
+
+  return s;
+}
+
+static clib_error_t *
+show_snat_command_fn (vlib_main_t * vm,
+		 unformat_input_t * input,
+		 vlib_cli_command_t * cmd)
+{
+  int verbose = 0;
+  snat_main_t * sm = &snat_main;
+  snat_user_t * u;
+
+  if (unformat (input, "detail"))
+    verbose = 1;
+  else if (unformat (input, "verbose"))
+    verbose = 2;
+
+  vlib_cli_output (vm, "%d users, %d outside addresses, %d active sessions",
+                   pool_elts (sm->users),
+                   vec_len (sm->addresses),
+                   pool_elts (sm->sessions));
+  
+  if (verbose > 0)
+    {
+      vlib_cli_output (vm, "%U", format_bihash_8_8, &sm->in2out,
+                       verbose - 1);
+      vlib_cli_output (vm, "%U", format_bihash_8_8, &sm->out2in,
+                       verbose - 1);
+      vlib_cli_output (vm, "%d list pool elements",
+                       pool_elts (sm->list_pool));
+
+      pool_foreach (u, sm->users,
+      ({
+        vlib_cli_output (vm, "%U", format_snat_user, sm, u, verbose - 1);
+      }));
+    }
+
+  return 0;
+}
+
+VLIB_CLI_COMMAND (show_snat_command, static) = {
+    .path = "show snat",
+    .short_help = "show snat",
+    .function = show_snat_command_fn,
+};