dhcp_proxy.c

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/*
 * proxy_node.c: common dhcp v4 and v6 proxy node processing
 *
 * 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 <dhcp/dhcp_proxy.h>
#include <vnet/fib/fib_table.h>
#include <vnet/mfib/mfib_table.h>

/**
 * @brief Shard 4/6 instance of DHCP main
 */
dhcp_proxy_main_t dhcp_proxy_main;

static void
dhcp_proxy_rx_table_lock (fib_protocol_t proto, u32 fib_index)
{
  if (FIB_PROTOCOL_IP4 == proto)
    fib_table_lock (fib_index, proto, FIB_SOURCE_DHCP);
  else
    mfib_table_lock (fib_index, proto, MFIB_SOURCE_DHCP);
}

static void
dhcp_proxy_rx_table_unlock (fib_protocol_t proto, u32 fib_index)
{
  if (FIB_PROTOCOL_IP4 == proto)
    fib_table_unlock (fib_index, proto, FIB_SOURCE_DHCP);
  else
    mfib_table_unlock (fib_index, proto, MFIB_SOURCE_DHCP);
}

u32
dhcp_proxy_rx_table_get_table_id (fib_protocol_t proto, u32 fib_index)
{
  if (FIB_PROTOCOL_IP4 == proto)
    {
      fib_table_t *fib;

      fib = fib_table_get (fib_index, proto);

      return (fib->ft_table_id);
    }
  else
    {
      mfib_table_t *mfib;

      mfib = mfib_table_get (fib_index, proto);

      return (mfib->mft_table_id);
    }
}

void
dhcp_proxy_walk (fib_protocol_t proto, dhcp_proxy_walk_fn_t fn, void *ctx)
{
  dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
  dhcp_proxy_t *server;
  u32 server_index, i;

  vec_foreach_index (i, dpm->dhcp_server_index_by_rx_fib_index[proto])
  {
    server_index = dpm->dhcp_server_index_by_rx_fib_index[proto][i];
    if (~0 == server_index)
      continue;

    server = pool_elt_at_index (dpm->dhcp_servers[proto], server_index);

    if (!fn (server, ctx))
      break;
  }
}

void
dhcp_vss_walk (fib_protocol_t proto, dhcp_vss_walk_fn_t fn, void *ctx)
{
  dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
  mfib_table_t *mfib;
  dhcp_vss_t *vss;
  u32 vss_index, i;
  fib_table_t *fib;

  vec_foreach_index (i, dpm->vss_index_by_rx_fib_index[proto])
  {
    vss_index = dpm->vss_index_by_rx_fib_index[proto][i];
    if (~0 == vss_index)
      continue;

    vss = pool_elt_at_index (dpm->vss[proto], vss_index);

    if (FIB_PROTOCOL_IP4 == proto)
      {
        fib = fib_table_get (i, proto);

        if (!fn (vss, fib->ft_table_id, ctx))
          break;
      }
    else
      {
        mfib = mfib_table_get (i, proto);

        if (!fn (vss, mfib->mft_table_id, ctx))
          break;
      }
  }
}

static u32
dhcp_proxy_server_find (dhcp_proxy_t * proxy,
                        fib_protocol_t proto,
                        ip46_address_t * addr, u32 server_table_id)
{
  dhcp_server_t *server;
  u32 ii, fib_index;

  vec_foreach_index (ii, proxy->dhcp_servers)
  {
    server = &proxy->dhcp_servers[ii];
    fib_index = fib_table_find (proto, server_table_id);

    if (ip46_address_is_equal (&server->dhcp_server,
                               addr) &&
        (server->server_fib_index == fib_index))
      {
        return (ii);
      }
  }
  return (~0);
}

int
dhcp_proxy_server_del (fib_protocol_t proto,
                       u32 rx_fib_index,
                       ip46_address_t * addr, u32 server_table_id)
{
  dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
  dhcp_proxy_t *proxy = 0;

  proxy = dhcp_get_proxy (dpm, rx_fib_index, proto);

  if (NULL != proxy)
    {
      dhcp_server_t *server;
      u32 index;

      index = dhcp_proxy_server_find (proxy, proto, addr, server_table_id);

      if (~0 != index)
        {
          server = &proxy->dhcp_servers[index];
          fib_table_unlock (server->server_fib_index, proto, FIB_SOURCE_DHCP);

          vec_del1 (proxy->dhcp_servers, index);

          if (0 == vec_len (proxy->dhcp_servers))
            {
              /* no servers left, delete the proxy config */
              dpm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] =
                ~0;
              vec_free (proxy->dhcp_servers);
              pool_put (dpm->dhcp_servers[proto], proxy);
              return (1);
            }
        }
    }

  /* the proxy still exists */
  return (0);
}

int
dhcp_proxy_server_add (fib_protocol_t proto,
                       ip46_address_t * addr,
                       ip46_address_t * src_address,
                       u32 rx_fib_index, u32 server_table_id)
{
  dhcp_proxy_main_t *dpm = &dhcp_proxy_main;
  dhcp_proxy_t *proxy = 0;
  int new = 0;

  proxy = dhcp_get_proxy (dpm, rx_fib_index, proto);

  if (NULL == proxy)
    {
      vec_validate_init_empty (dpm->dhcp_server_index_by_rx_fib_index[proto],
                               rx_fib_index, ~0);

      pool_get (dpm->dhcp_servers[proto], proxy);
      clib_memset (proxy, 0, sizeof (*proxy));
      new = 1;

      dpm->dhcp_server_index_by_rx_fib_index[proto][rx_fib_index] =
        proxy - dpm->dhcp_servers[proto];

      proxy->dhcp_src_address = *src_address;
      proxy->rx_fib_index = rx_fib_index;
    }
  else
    {
      if (~0 != dhcp_proxy_server_find (proxy, proto, addr, server_table_id))
        {
          return (new);
        }
    }

  dhcp_server_t server = {
    .dhcp_server = *addr,
    .server_fib_index = fib_table_find_or_create_and_lock (proto,
                                                           server_table_id,
                                                           FIB_SOURCE_DHCP),
  };

  vec_add1 (proxy->dhcp_servers, server);

  return (new);
}

typedef struct dhcp4_proxy_dump_walk_ctx_t_
{
  fib_protocol_t proto;
  void *opaque;
  u32 context;
} dhcp_proxy_dump_walk_cxt_t;

static int
dhcp_proxy_dump_walk (dhcp_proxy_t * proxy, void *arg)
{
  dhcp_proxy_dump_walk_cxt_t *ctx = arg;

  dhcp_send_details (ctx->proto, ctx->opaque, ctx->context, proxy);

  return (1);
}

void
dhcp_proxy_dump (fib_protocol_t proto, void *opaque, u32 context)
{
  dhcp_proxy_dump_walk_cxt_t ctx = {
    .proto = proto,
    .opaque = opaque,
    .context = context,
  };
  dhcp_proxy_walk (proto, dhcp_proxy_dump_walk, &ctx);
}

int
dhcp_vss_show_walk (dhcp_vss_t * vss, u32 rx_table_id, void *ctx)
{
  vlib_main_t *vm = ctx;

  if (vss->vss_type == VSS_TYPE_VPN_ID)
    {
      u32 oui = ((u32) vss->vpn_id[0] << 16) + ((u32) vss->vpn_id[1] << 8)
        + ((u32) vss->vpn_id[2]);
      u32 fib_id = ((u32) vss->vpn_id[3] << 24) + ((u32) vss->vpn_id[4] << 16)
        + ((u32) vss->vpn_id[5] << 8) + ((u32) vss->vpn_id[6]);
      vlib_cli_output (vm, " fib_table: %d  oui: %d vpn_index: %d",
                       rx_table_id, oui, fib_id);
    }
  else if (vss->vss_type == VSS_TYPE_ASCII)
    vlib_cli_output (vm, " fib_table: %d  vpn_id: %s",
                     rx_table_id, vss->vpn_ascii_id);
  else
    vlib_cli_output (vm, " fib_table: %d  default global vpn", rx_table_id);

  return (1);
}

void
update_vss (dhcp_vss_t * v,
            u8 vss_type, u8 * vpn_ascii_id, u32 oui, u32 vpn_index)
{
  v->vss_type = vss_type;
  if (v->vpn_ascii_id)
    {
      if (v->vpn_ascii_id == (u8 *) ~ 0)
        v->vpn_ascii_id = 0;
      else
        vec_free (v->vpn_ascii_id);
    }

  if (vss_type == VSS_TYPE_ASCII)
    v->vpn_ascii_id = vpn_ascii_id;
  else if (vss_type == VSS_TYPE_VPN_ID)
    {
      v->vpn_id[0] = (oui >> 16) & 0xff;
      v->vpn_id[1] = (oui >> 8) & 0xff;
      v->vpn_id[2] = (oui >> 0) & 0xff;
      v->vpn_id[3] = (vpn_index >> 24) & 0xff;
      v->vpn_id[4] = (vpn_index >> 16) & 0xff;
      v->vpn_id[5] = (vpn_index >> 8) & 0xff;
      v->vpn_id[6] = (vpn_index >> 0) & 0xff;
    }
}

int
dhcp_proxy_set_vss (fib_protocol_t proto,
                    u32 tbl_id,
                    u8 vss_type,
                    u8 * vpn_ascii_id, u32 oui, u32 vpn_index, u8 is_del)
{
  dhcp_proxy_main_t *dm = &dhcp_proxy_main;
  dhcp_vss_t *v = NULL;
  u32 rx_fib_index;
  int rc = 0;

  if (proto == FIB_PROTOCOL_IP4)
    rx_fib_index = fib_table_find_or_create_and_lock (proto, tbl_id,
                                                      FIB_SOURCE_DHCP);
  else
    rx_fib_index = mfib_table_find_or_create_and_lock (proto, tbl_id,
                                                       MFIB_SOURCE_DHCP);
  v = dhcp_get_vss_info (dm, rx_fib_index, proto);

  if (NULL != v)
    {
      if (is_del)
        {
          /* release the lock held on the table when the VSS
           * info was created */
          dhcp_proxy_rx_table_unlock (proto, rx_fib_index);

          vec_free (v->vpn_ascii_id);
          pool_put (dm->vss[proto], v);
          dm->vss_index_by_rx_fib_index[proto][rx_fib_index] = ~0;
        }
      else
        {
          update_vss (v, vss_type, vpn_ascii_id, oui, vpn_index);
        }
    }
  else
    {
      if (is_del)
        rc = VNET_API_ERROR_NO_SUCH_ENTRY;
      else
        {
          /* create a new entry */
          vec_validate_init_empty (dm->vss_index_by_rx_fib_index[proto],
                                   rx_fib_index, ~0);

          /* hold a lock on the table whilst the VSS info exist */
          pool_get (dm->vss[proto], v);
          update_vss (v, vss_type, vpn_ascii_id, oui, vpn_index);
          dm->vss_index_by_rx_fib_index[proto][rx_fib_index] =
            v - dm->vss[proto];
          dhcp_proxy_rx_table_lock (proto, rx_fib_index);
        }
    }

  /* Release the lock taken during the create_or_lock at the start */
  dhcp_proxy_rx_table_unlock (proto, rx_fib_index);

  return (rc);
}

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */