l2tp.c

Go to the documentation of this file.

/*
 * l2tp.c : L2TPv3 tunnel support
 *
 * Copyright (c) 2013 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 <vppinfra/error.h>
#include <vppinfra/hash.h>
#include <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/l2/l2_input.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/l2tp/l2tp.h>

l2t_main_t l2t_main;

/* packet trace format function */
u8 * format_l2t_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 *);
  l2t_trace_t * t = va_arg (*args, l2t_trace_t *);
  
  if (t->is_user_to_network)
    s = format (s, "L2T: %U (client) -> %U (our) session %d", 
                format_ip6_address, &t->client_address,
                format_ip6_address, &t->our_address,
                t->session_index);
  else
    s = format (s, "L2T: %U (our) -> %U (client) session %d)",
                format_ip6_address, &t->our_address,
                  format_ip6_address, &t->client_address,
                  t->session_index);
  return s;
}

u8 * format_l2t_session (u8 * s, va_list * args)
{
  l2t_session_t * session = va_arg (*args, l2t_session_t *);
  l2t_main_t * lm = &l2t_main;
  u32 counter_index;
  vlib_counter_t v;

  s = format (s, "[%d] %U (our) %U (client) %U (sw_if_index %d)\n", 
              session - lm->sessions,
              format_ip6_address, &session->our_address,
              format_ip6_address, &session->client_address,
              format_vnet_sw_interface_name, lm->vnet_main,
              vnet_get_sw_interface (lm->vnet_main, session->sw_if_index),
              session->sw_if_index);

  s = format (s, "   local cookies %016llx %016llx remote cookie %016llx\n",
              clib_net_to_host_u64 (session->local_cookie[0]),
              clib_net_to_host_u64 (session->local_cookie[1]),
              clib_net_to_host_u64 (session->remote_cookie));

  s = format (s, "   local session-id %d remote session-id %d\n",
              clib_net_to_host_u32 (session->local_session_id),
              clib_net_to_host_u32 (session->remote_session_id));

  s = format (s, "   l2 specific sublayer %s\n", 
              session->l2_sublayer_present ? "preset" : "absent");

  counter_index = 
    session_index_to_counter_index (session - lm->sessions,
                                    SESSION_COUNTER_USER_TO_NETWORK);

  vlib_get_combined_counter (&lm->counter_main, counter_index, &v);
  if (v.packets != 0)
    s = format (s, "   user-to-net: %llu pkts %llu bytes\n",
                v.packets, v.bytes);

  vlib_get_combined_counter (&lm->counter_main, counter_index+1, &v);

  if (v.packets != 0)
    s = format (s, "   net-to-user: %llu pkts %llu bytes\n",
                v.packets, v.bytes);
  return s;
}

static clib_error_t *
show_l2tp_command_fn (vlib_main_t * vm,
                      unformat_input_t * input,
                      vlib_cli_command_t * cmd)
{
  l2t_session_t *session;
  l2t_main_t *lm = &l2t_main;
  char * keystr = 0;
  int verbose = 0;
  
  if (unformat (input, "verbose") || unformat (input, "v"))
    verbose = 1;

  if (pool_elts (lm->sessions) == 0)
      vlib_cli_output (vm, "No l2tp sessions...");
  else
      vlib_cli_output (vm, "%u l2tp sessions...", pool_elts (lm->sessions));

  if (verbose)
    {
      switch (lm->lookup_type)
        {
        case L2T_LOOKUP_SRC_ADDRESS:
          keystr = "src address";
          break;

        case L2T_LOOKUP_DST_ADDRESS:
          keystr = "dst address";
          break;

        case L2T_LOOKUP_SESSION_ID:
          keystr = "session id";
          break;

        default:
          keystr = "BOGUS!";
          break;
        }

      vlib_cli_output (vm, "L2tp session lookup on %s", keystr);

      pool_foreach (session, lm->sessions, 
      ({
        vlib_cli_output (vm, "%U", format_l2t_session, session);
      }));
    }
  
  return 0;
}

VLIB_CLI_COMMAND (show_session_detail_command, static) = {
  .path = "show l2tpv3",
  .short_help = "show l2tpv3 [verbose]",
  .function = show_l2tp_command_fn,
};

static clib_error_t *
test_counters_command_fn (vlib_main_t * vm,
                          unformat_input_t * input,
                          vlib_cli_command_t * cmd)
{
  l2t_session_t *session;
  l2t_main_t *lm = &l2t_main;
  u32 session_index;
  u32 counter_index;
  u32 nincr=0;
  u32 cpu_index = os_get_cpu_number();

  pool_foreach (session, lm->sessions, 
  ({
    session_index = session - lm->sessions;
    counter_index = 
      session_index_to_counter_index (session_index, 
                                      SESSION_COUNTER_USER_TO_NETWORK);
    vlib_increment_combined_counter (&lm->counter_main,
                                     cpu_index, 
                                     counter_index, 
                                     1/*pkt*/, 1111 /*bytes*/);
    vlib_increment_combined_counter (&lm->counter_main,
                                     cpu_index, 
                                     counter_index+1, 
                                     1/*pkt*/, 2222 /*bytes*/);
    nincr++;
    
  }));
  vlib_cli_output (vm, "Incremented %d active counters\n", nincr);
  
  return 0;
}

VLIB_CLI_COMMAND (test_counters_command, static) = {
    .path = "test counters",
    .short_help = "increment all active counters",
    .function = test_counters_command_fn,
};

static clib_error_t *
clear_counters_command_fn (vlib_main_t * vm,
                          unformat_input_t * input,
                          vlib_cli_command_t * cmd)
{
  l2t_session_t *session;
  l2t_main_t *lm = &l2t_main;
  u32 session_index;
  u32 counter_index;
  u32 nincr=0;
  
  pool_foreach (session, lm->sessions, 
  ({
    session_index = session - lm->sessions;
    counter_index = 
      session_index_to_counter_index (session_index, 
                                      SESSION_COUNTER_USER_TO_NETWORK);
    vlib_zero_combined_counter (&lm->counter_main, counter_index);
    vlib_zero_combined_counter (&lm->counter_main, counter_index+1);
    nincr++;
    
  }));
  vlib_cli_output (vm, "Cleared %d active counters\n", nincr);
  
  return 0;
}

VLIB_CLI_COMMAND (clear_counters_command, static) = {
    .path = "clear counters",
    .short_help = "clear all active counters",
    .function = clear_counters_command_fn,
};

static u8 * format_l2tpv3_name (u8 * s, va_list * args)
{
  l2t_main_t *lm = &l2t_main;
  u32 i = va_arg (*args, u32);
  u32 show_dev_instance = ~0;

  if (i < vec_len (lm->dev_inst_by_real))
    show_dev_instance = lm->dev_inst_by_real[i];

  if (show_dev_instance != ~0)
    i = show_dev_instance;

  return format (s, "l2tpv3_tunnel%d", i);
}

static int l2tpv3_name_renumber (vnet_hw_interface_t * hi,
                                 u32 new_dev_instance)
{
  l2t_main_t *lm = &l2t_main;

  vec_validate_init_empty (lm->dev_inst_by_real, hi->dev_instance, ~0);

  lm->dev_inst_by_real [hi->dev_instance] = new_dev_instance;

  return 0;
}

static uword dummy_interface_tx (vlib_main_t * vm,
                                 vlib_node_runtime_t * node,
                                 vlib_frame_t * frame)
{
  clib_warning ("you shouldn't be here, leaking buffers...");
  return frame->n_vectors;
}

VNET_DEVICE_CLASS (l2tpv3_device_class,static) = {
  .name = "L2TPv3",
  .format_device_name = format_l2tpv3_name,
  .name_renumber = l2tpv3_name_renumber,
  .tx_function = dummy_interface_tx,
};

static uword dummy_set_rewrite (vnet_main_t * vnm,
                                u32 sw_if_index,
                                u32 l3_type,
                                void * dst_address,
                                void * rewrite,
                                uword max_rewrite_bytes)
{
  /*
   * Conundrum: packets from tun/tap destined for the tunnel
   * actually have this rewrite applied. Transit packets do not.
   * To make the two cases equivalent, don't generate a
   * rewrite here, build the entire header in the fast path.
   */
  return 0;
}

static u8 * format_l2tp_header_with_length (u8 * s, va_list * args)
{
  u32 dev_instance = va_arg (*args, u32);
  s = format (s, "unimplemented dev %u", dev_instance);
  return s;
}

VNET_HW_INTERFACE_CLASS (l2tpv3_hw_class) = {
  .name = "L2TPV3",
  .format_header = format_l2tp_header_with_length,
  .set_rewrite = dummy_set_rewrite,
};

int create_l2tpv3_ipv6_tunnel (l2t_main_t * lm,
                               ip6_address_t * client_address,
                               ip6_address_t * our_address,
                               u32 local_session_id,
                               u32 remote_session_id,
                               u64 local_cookie,
                               u64 remote_cookie,
                               int l2_sublayer_present, 
                               u32 * sw_if_index)
{
  l2t_session_t *s = 0;
  vnet_main_t * vnm = lm->vnet_main;
  vnet_hw_interface_t * hi;
  uword * p = (uword *) ~0;
  u32 hw_if_index;
  l2tpv3_header_t l2tp_hdr;
  ip6_address_t * dst_address_copy, * src_address_copy;
  u32 counter_index;

  remote_session_id = clib_host_to_net_u32 (remote_session_id);
  local_session_id  = clib_host_to_net_u32 (local_session_id);

  switch (lm->lookup_type) {
  case L2T_LOOKUP_SRC_ADDRESS:
    p = hash_get_mem (lm->session_by_src_address, client_address);
    break;
    
  case L2T_LOOKUP_DST_ADDRESS:
    p = hash_get_mem (lm->session_by_dst_address, our_address);
    break;

  case L2T_LOOKUP_SESSION_ID:
    p = hash_get (lm->session_by_session_id, local_session_id);
    break;

  default:
    ASSERT(0);
  }

  /* adding a session: session must not already exist */
  if (p) 
    return VNET_API_ERROR_INVALID_VALUE;

  pool_get (lm->sessions, s);
  memset (s, 0, sizeof (*s));
  clib_memcpy (&s->our_address, our_address, sizeof (s->our_address));
  clib_memcpy (&s->client_address, client_address, sizeof (s->client_address));
  s->local_cookie[0] = clib_host_to_net_u64 (local_cookie);
  s->remote_cookie = clib_host_to_net_u64 (remote_cookie);
  s->local_session_id = local_session_id;
  s->remote_session_id = remote_session_id;
  s->l2_sublayer_present = l2_sublayer_present;
  /* precompute l2tp header size */
  s->l2tp_hdr_size = l2_sublayer_present ? 
    sizeof (l2tpv3_header_t) :
    sizeof (l2tpv3_header_t) - sizeof(l2tp_hdr.l2_specific_sublayer);

  /* Setup hash table entries */
  switch (lm->lookup_type) {
  case L2T_LOOKUP_SRC_ADDRESS:
    src_address_copy = clib_mem_alloc (sizeof (*src_address_copy));
    clib_memcpy (src_address_copy, client_address, sizeof (*src_address_copy));
    hash_set_mem (lm->session_by_src_address, src_address_copy, 
                  s - lm->sessions);
    break;
  case L2T_LOOKUP_DST_ADDRESS:
    dst_address_copy = clib_mem_alloc (sizeof (*dst_address_copy));
    clib_memcpy (dst_address_copy, our_address, sizeof (*dst_address_copy));
    hash_set_mem (lm->session_by_dst_address, dst_address_copy, 
                  s - lm->sessions);
    break;
  case L2T_LOOKUP_SESSION_ID:
    hash_set (lm->session_by_session_id, local_session_id, 
              s - lm->sessions);
    break;

  default:
    ASSERT(0);
  }

  /* validate counters */
  counter_index = 
    session_index_to_counter_index (s - lm->sessions,
                                    SESSION_COUNTER_USER_TO_NETWORK);
  vlib_validate_combined_counter (&lm->counter_main, counter_index);
  vlib_validate_combined_counter (&lm->counter_main, counter_index+1);
  
  if (vec_len (lm->free_l2tpv3_tunnel_hw_if_indices) > 0)
    {
      hw_if_index = lm->free_l2tpv3_tunnel_hw_if_indices
        [vec_len (lm->free_l2tpv3_tunnel_hw_if_indices)-1];
      _vec_len (lm->free_l2tpv3_tunnel_hw_if_indices) -= 1;

      hi = vnet_get_hw_interface (vnm, hw_if_index);
      hi->dev_instance = s - lm->sessions;
      hi->hw_instance = hi->dev_instance;
    }
  else 
    {
      hw_if_index = vnet_register_interface
        (vnm, l2tpv3_device_class.index, s - lm->sessions,
         l2tpv3_hw_class.index, s - lm->sessions);
      hi = vnet_get_hw_interface (vnm, hw_if_index);
      hi->output_node_index = l2t_encap_node.index;
      /* $$$$ initialize custom dispositions, if needed */
    }
  
  s->hw_if_index = hw_if_index;
  s->sw_if_index = hi->sw_if_index;

  if (sw_if_index)
    *sw_if_index = hi->sw_if_index;

  vnet_sw_interface_set_flags (vnm, hi->sw_if_index, 
                               VNET_SW_INTERFACE_FLAG_ADMIN_UP);

  return 0;
}

static clib_error_t *
create_l2tpv3_tunnel_command_fn (vlib_main_t * vm,
                                 unformat_input_t * input,
                                 vlib_cli_command_t * cmd)
{
  ip6_address_t client_address, our_address;
  unformat_input_t _line_input, * line_input = &_line_input;
  l2t_main_t *lm = &l2t_main;
  u64 local_cookie = (u64)~0, remote_cookie = (u64)~0;
  u32 local_session_id = 1, remote_session_id = 1;
  int our_address_set = 0, client_address_set = 0;
  int l2_sublayer_present = 0;
  int rv;
  u32 sw_if_index;

  /* Get a line of input. */
  if (! unformat_user (input, unformat_line_input, line_input))
    return 0;

  while (unformat_check_input (line_input) != UNFORMAT_END_OF_INPUT) {
    if (unformat (line_input, "client %U", 
                  unformat_ip6_address, &client_address))
      client_address_set = 1;
    else if (unformat (line_input, "our %U",
                       unformat_ip6_address, &our_address))
      our_address_set = 1;
    else if (unformat (line_input, "local-cookie %llx", &local_cookie))
      ;
    else if (unformat (line_input, "remote-cookie %llx", &remote_cookie))
      ;
    else if (unformat (line_input, "local-session-id %d", 
                       &local_session_id))
      ;
    else if (unformat (line_input, "remote-session-id %d", 
                       &remote_session_id))
      ;
    else if (unformat (line_input, "l2-sublayer-present"))
      l2_sublayer_present = 1;
    else 
      return clib_error_return (0, "parse error: '%U'", 
                                format_unformat_error, line_input);
  }

  unformat_free (line_input);

  if (our_address_set == 0)
    return clib_error_return (0, "our address not specified");
  if (client_address_set == 0)
    return clib_error_return (0, "client address not specified");
  
  rv = create_l2tpv3_ipv6_tunnel (lm, &client_address, &our_address,
                                  local_session_id, remote_session_id,
                                  local_cookie, remote_cookie,
                                  l2_sublayer_present, 
                                  &sw_if_index);
  switch(rv)
    {
    case 0:
      break;
    case VNET_API_ERROR_INVALID_VALUE:
      return clib_error_return (0, "session already exists...");

    case VNET_API_ERROR_NO_SUCH_ENTRY:
      return clib_error_return (0, "session does not exist...");

    default:
      return clib_error_return (0, "l2tp_session_add_del returned %d", rv);
    }

  return 0;
}

VLIB_CLI_COMMAND (create_l2tpv3_tunnel_command, static) = {
    .path = "create l2tpv3 tunnel",
    .short_help = 
    "create l2tpv3 tunnel client <ip6> our <ip6> local-cookie <hex> remote-cookie <hex> local-session <dec> remote-session <dec>",
    .function = create_l2tpv3_tunnel_command_fn,
};

int l2tpv3_set_tunnel_cookies (l2t_main_t * lm,
                               u32 sw_if_index,
                               u64 new_local_cookie,
                               u64 new_remote_cookie)
{
    l2t_session_t *s;
    vnet_hw_interface_t * hi;
    vnet_main_t * vnm = vnet_get_main();
    hi = vnet_get_sup_hw_interface (vnm, sw_if_index);

    if (pool_is_free_index (lm->sessions, hi->dev_instance))
        return VNET_API_ERROR_INVALID_VALUE;

    s = pool_elt_at_index (lm->sessions, hi->dev_instance);

    s->local_cookie[1] = s->local_cookie[0];
    s->local_cookie[0] = clib_host_to_net_u64(new_local_cookie);
    s->remote_cookie = clib_host_to_net_u64(new_remote_cookie);

    return 0;
}


static clib_error_t *
set_l2tp_tunnel_cookie_command_fn (vlib_main_t * vm,
                                unformat_input_t * input,
                                vlib_cli_command_t * cmd)
{
  l2t_main_t *lm = &l2t_main;
  vnet_main_t * vnm = vnet_get_main();
  u32 sw_if_index = ~0;
  u64 local_cookie = (u64)~0, remote_cookie = (u64)~0;

  int rv;
  
  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%U", unformat_vnet_sw_interface, vnm, 
                    &sw_if_index))
        ;
      else if (unformat (input, "local %llx", &local_cookie))
        ;
      else if (unformat (input, "remote %llx", &remote_cookie))
        ;
      else
        break;
    }
  if (sw_if_index == ~0)
    return clib_error_return (0, "unknown interface");
  if (local_cookie == ~0)
    return clib_error_return (0, "local cookie required");
  if (remote_cookie == ~0)
    return clib_error_return (0, "remote cookie required");

  rv = l2tpv3_set_tunnel_cookies (lm, sw_if_index, 
                                  local_cookie, remote_cookie);

  switch (rv)
    {
    case 0:
      break;

    case VNET_API_ERROR_INVALID_SW_IF_INDEX:
      return clib_error_return (0, "invalid interface");

    default:
      return clib_error_return (0, "l2tp_session_set_cookies returned %d",
                                rv);
    }

    return 0;
}

VLIB_CLI_COMMAND (set_l2tp_tunnel_cookie_command, static) = {
    .path = "set l2tpv3 tunnel cookie",
    .short_help = 
    "set l2tpv3 tunnel cookie <intfc> local <hex> remote <hex>",
    .function = set_l2tp_tunnel_cookie_command_fn,
};

int l2tpv3_interface_enable_disable (vnet_main_t * vnm, 
                                     u32 sw_if_index, 
                                     int enable_disable)
{
  ip6_main_t * im = &ip6_main;
  ip_lookup_main_t * lm = &im->lookup_main;
  ip_config_main_t * rx_cm = &lm->rx_config_mains[VNET_UNICAST];
  u32 ci;
  ip6_l2tpv3_config_t config;
  ip6_rx_feature_type_t type;

  if (pool_is_free_index (vnm->interface_main.sw_interfaces, sw_if_index))
    return VNET_API_ERROR_INVALID_SW_IF_INDEX;

  type = IP6_RX_FEATURE_L2TPV3;

  ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
  ci = (enable_disable
        ? vnet_config_add_feature
        : vnet_config_del_feature)
    (vlib_get_main(), &rx_cm->config_main,
     ci,
     type,
     &config,
     sizeof (config));
  rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;
  return 0;
}

/* Enable/disable L2TPv3 intercept on IP6 fowarding path */
static clib_error_t *
set_ip6_l2tpv3 (vlib_main_t * vm,
                unformat_input_t * input,
                vlib_cli_command_t * cmd)
{
  u32 sw_if_index = ~0;
  int is_add = 1;
  int rv;
  vnet_main_t * vnm = vnet_get_main();

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "%U", unformat_vnet_sw_interface, vnm, 
                    &sw_if_index))
        ;
      else if (unformat (input, "del"))
        is_add = 0;
      else
        break;
    }

  if (sw_if_index == ~0)
    return clib_error_return (0, "interface required");
  
  rv = l2tpv3_interface_enable_disable (vnm, sw_if_index, is_add);

  switch (rv)
    {
    case 0:
      break;

    case VNET_API_ERROR_INVALID_SW_IF_INDEX:
      return clib_error_return (0, "invalid interface");

    default:
      return clib_error_return (0, "l2tp_interface_enable_disable returned %d",
                                rv);
    }
  return 0;
}

VLIB_CLI_COMMAND (set_interface_ip6_l2tpv3, static) = {
  .path = "set interface ip6 l2tpv3",
  .function = set_ip6_l2tpv3,
  .short_help = "set interface ip6 l2tpv3 <intfc> [del]",
};

static clib_error_t *
l2tp_config (vlib_main_t * vm, unformat_input_t * input)
{
    l2t_main_t *lm = &l2t_main;

    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
        if (unformat (input, "lookup-v6-src"))
            lm->lookup_type = L2T_LOOKUP_SRC_ADDRESS;
        else if (unformat (input, "lookup-v6-dst"))
            lm->lookup_type = L2T_LOOKUP_DST_ADDRESS;
        else if (unformat (input, "lookup-session-id"))
            lm->lookup_type = L2T_LOOKUP_SESSION_ID;
        else return clib_error_return (0, "unknown input `%U'",
                                       format_unformat_error, input);
    }
    return 0;
}

VLIB_CONFIG_FUNCTION (l2tp_config, "l2tp");

clib_error_t *l2tp_init (vlib_main_t *vm)
{
    l2t_main_t *lm = &l2t_main;
    ip_main_t * im = &ip_main;
    ip_protocol_info_t * pi;

    lm->vnet_main = vnet_get_main();
    lm->vlib_main = vm;
    lm->lookup_type = L2T_LOOKUP_DST_ADDRESS;

    lm->session_by_src_address = hash_create_mem
        (0, sizeof (ip6_address_t) /* key bytes */,
         sizeof (u32) /* value bytes */);
    lm->session_by_dst_address = hash_create_mem
        (0, sizeof (ip6_address_t) /* key bytes */,
         sizeof (u32) /* value bytes */);
    lm->session_by_session_id = hash_create (0, sizeof (uword));

    pi = ip_get_protocol_info (im, IP_PROTOCOL_L2TP);
    pi->unformat_pg_edit = unformat_pg_l2tp_header;

    /* insure these nodes are included in build */
    l2tp_encap_init(vm);
    l2tp_decap_init();

    return 0;
}

VLIB_INIT_FUNCTION(l2tp_init);