dhcp6_client_common_dp.c

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/*
 * Copyright (c) 2018 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/ethernet/ethernet.h>
#include <dhcp/dhcp6_packet.h>
#include <dhcp/dhcp6_client_common_dp.h>
#include <dhcp/dhcp6_ia_na_client_dp.h>
#include <dhcp/dhcp6_pd_client_dp.h>
#include <dhcp/dhcp6_packet.h>
#include <vnet/udp/udp.h>

dhcp6_client_common_main_t dhcp6_client_common_main;
dhcpv6_duid_ll_string_t client_duid;

u32
server_index_get_or_create (u8 * data, u16 len)
{
  dhcp6_client_common_main_t *ccm = &dhcp6_client_common_main;
  u32 i;
  server_id_t *se;
  server_id_t new_se;

  for (i = 0; i < vec_len (ccm->server_ids); i++)
    {
      se = &ccm->server_ids[i];
      if (se->len == len && 0 == memcmp (se->data, data, len))
        return i;
    }

  new_se.len = len;
  new_se.data = 0;
  vec_validate (new_se.data, len - 1);
  memcpy (new_se.data, data, len);

  vec_add1 (ccm->server_ids, new_se);

  return vec_len (ccm->server_ids) - 1;
}

static void
generate_client_duid (void)
{
  client_duid.duid_type = clib_host_to_net_u16 (DHCPV6_DUID_LL);
  client_duid.hardware_type = clib_host_to_net_u16 (1);

  vnet_main_t *vnm = vnet_get_main ();
  vnet_interface_main_t *im = &vnm->interface_main;
  vnet_hw_interface_t *hi;
  ethernet_interface_t *eth_if = 0;

  /* *INDENT-OFF* */
  pool_foreach (hi, im->hw_interfaces,
  ({
    eth_if = ethernet_get_interface (&ethernet_main, hi->hw_if_index);
    if (eth_if)
      break;
  }));
  /* *INDENT-ON* */

  if (eth_if)
    clib_memcpy (client_duid.lla, eth_if->address, 6);
  else
    {
      clib_warning ("Failed to find any Ethernet interface, "
                    "setting DHCPv6 DUID link-layer address to random value");
      u32 seed = random_default_seed ();
      random_u32 (&seed);
      client_duid.lla[0] = 0xc2;        /* locally administered unicast */
      client_duid.lla[1] = 0x18;
      client_duid.lla[2] = 0x44;
      client_duid.lla[3] = random_u32 (&seed);
      client_duid.lla[4] = random_u32 (&seed);
      client_duid.lla[5] = random_u32 (&seed);
    }
}

#define foreach_dhcpv6_client \
  _(DROP, "error-drop")       \
  _(LOOKUP, "ip6-lookup")

typedef enum
{
#define _(sym,str) DHCPV6_CLIENT_NEXT_##sym,
  foreach_dhcpv6_client
#undef _
    DHCPV6_CLIENT_N_NEXT,
} dhcpv6_client_next_t;

/**
 * per-packet trace data
 */
typedef struct dhcpv6_client_trace_t_
{
} dhcpv6_client_trace_t;

static u8 *
format_dhcpv6_client_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 *);
  //dhcpv6_client_trace_t *t = va_arg (*args, dhcpv6_client_trace_t *);

  s = format (s, "nothing");

  return s;
}

static uword
dhcpv6_client_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
                       vlib_frame_t * frame)
{
  dhcp6_ia_na_client_main_t *icm = &dhcp6_ia_na_client_main;
  dhcp6_pd_client_main_t *pcm = &dhcp6_pd_client_main;

  dhcpv6_client_next_t next_index;
  u32 n_left_from, *from, *to_next;
  next_index = 0;
  n_left_from = frame->n_vectors;
  from = vlib_frame_vector_args (frame);

  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 > 0 && n_left_to_next > 0)
        {
          ip6_header_t *ip0;
          u32 options_length;
          dhcpv6_header_t *dhcpv60;
          dhcpv6_option_t *option;
          vlib_buffer_t *b0;
          dhcp6_report_common_t report;
          dhcp6_address_info_t *addresses = 0;
          dhcp6_prefix_info_t *prefixes = 0;
          u32 next0 = DHCPV6_CLIENT_NEXT_DROP;
          u32 bi0;
          u32 xid;
          u32 sw_if_index;
          u32 iaid;
          u8 client_id_present = 0;
          u8 discard = 0;
          u8 is_pd_packet = 0;

          dhcp6_ia_na_client_state_t *ia_na_client_state = NULL;
          dhcp6_pd_client_state_t *pd_client_state = NULL;

          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);

          dhcpv60 = vlib_buffer_get_current (b0);
          ip0 = (void *) (b0->data + vnet_buffer (b0)->l3_hdr_offset);
          u32 dhcpv6_ip6_payload_offset =
            (u8 *) dhcpv60 - ((u8 *) ip0 + sizeof (*ip0));
          options_length =
            clib_net_to_host_u16 (ip0->payload_length) -
            dhcpv6_ip6_payload_offset - sizeof (*dhcpv60);

          clib_memset (&report, 0, sizeof (report));

          sw_if_index = vnet_buffer (b0)->sw_if_index[VLIB_RX];
          if (sw_if_index >= vec_len (icm->client_state_by_sw_if_index))
            ia_na_client_state = 0;
          else
            ia_na_client_state =
              &icm->client_state_by_sw_if_index[sw_if_index];
          if (sw_if_index >= vec_len (pcm->client_state_by_sw_if_index))
            pd_client_state = 0;
          else
            pd_client_state = &pcm->client_state_by_sw_if_index[sw_if_index];

          xid =
            (dhcpv60->xid[0] << 16) + (dhcpv60->xid[1] << 8) +
            dhcpv60->xid[2];
          if (ia_na_client_state && ia_na_client_state->transaction_id == xid)
            is_pd_packet = 0;
          else if (pd_client_state && pd_client_state->transaction_id == xid)
            is_pd_packet = 1;
          else
            {
              clib_warning
                ("Received DHCPv6 message with wrong Transaction ID");
              discard = 1;
            }

          report.sw_if_index = sw_if_index;
          report.msg_type = dhcpv60->msg_type;
          report.server_index = ~0;

          switch (dhcpv60->msg_type)
            {
            case DHCPV6_MSG_ADVERTISE:
            case DHCPV6_MSG_REPLY:
              option = (dhcpv6_option_t *) (dhcpv60 + 1);
              while (options_length > 0)
                {
                  if (options_length <
                      clib_net_to_host_u16 (option->length) +
                      sizeof (*option))
                    {
                      clib_warning
                        ("remaining payload length < option length (%d < %d)",
                         options_length,
                         clib_net_to_host_u16 (option->length) +
                         sizeof (*option));
                      break;
                    }
                  u16 oo = clib_net_to_host_u16 (option->option);
                  if (oo == DHCPV6_OPTION_IA_NA || oo == DHCPV6_OPTION_IA_PD)
                    {
                      u8 discard_option = 0;
                      dhcpv6_ia_header_t *ia_header = (void *) option;
                      iaid = clib_net_to_host_u32 (ia_header->iaid);
                      u32 T1 = clib_net_to_host_u32 (ia_header->t1);
                      u32 T2 = clib_net_to_host_u32 (ia_header->t2);
                      if (iaid != DHCPV6_CLIENT_IAID)
                        discard_option = 1;
                      if (T1 != 0 && T2 != 0 && T1 > T2)
                        discard_option = 1;
                      if (!discard_option)
                        {
                          report.T1 = T1;
                          report.T2 = T2;
                        }
                      dhcpv6_option_t *inner_option =
                        (void *) ia_header->data;
                      u16 inner_options_length =
                        clib_net_to_host_u16 (option->length) -
                        (sizeof (*ia_header) - sizeof (dhcpv6_option_t));
                      while (inner_options_length > 0)
                        {
                          u16 inner_oo =
                            clib_net_to_host_u16 (inner_option->option);
                          if (discard_option)
                            ;
                          else if (inner_oo == DHCPV6_OPTION_IAADDR)
                            {
                              dhcpv6_ia_opt_addr_t *iaaddr =
                                (void *) inner_option;
                              u32 n_addresses = vec_len (addresses);
                              vec_validate (addresses, n_addresses);
                              dhcp6_address_info_t *address_info =
                                &addresses[n_addresses];
                              address_info->preferred_time =
                                clib_net_to_host_u32 (iaaddr->preferred);
                              address_info->valid_time =
                                clib_net_to_host_u32 (iaaddr->valid);
                              address_info->address = iaaddr->addr;
                            }
                          else if (inner_oo == DHCPV6_OPTION_IAPREFIX)
                            {
                              dhcpv6_ia_opt_pd_t *iaprefix =
                                (void *) inner_option;
                              u32 n_prefixes = vec_len (prefixes);
                              vec_validate (prefixes, n_prefixes);
                              dhcp6_prefix_info_t *prefix_info =
                                &prefixes[n_prefixes];
                              prefix_info->preferred_time =
                                clib_net_to_host_u32 (iaprefix->preferred);
                              prefix_info->valid_time =
                                clib_net_to_host_u32 (iaprefix->valid);
                              prefix_info->prefix_length = iaprefix->prefix;
                              prefix_info->prefix = iaprefix->addr;
                            }
                          else if (inner_oo == DHCPV6_OPTION_STATUS_CODE)
                            {
                              dhcpv6_status_code_t *sc =
                                (void *) inner_option;
                              report.inner_status_code =
                                clib_net_to_host_u16 (sc->status_code);
                            }
                          inner_options_length -=
                            sizeof (*inner_option) +
                            clib_net_to_host_u16 (inner_option->length);
                          inner_option =
                            (void *) ((u8 *) inner_option +
                                      sizeof (*inner_option) +
                                      clib_net_to_host_u16
                                      (inner_option->length));
                        }
                    }
                  else if (oo == DHCPV6_OPTION_CLIENTID)
                    {
                      if (client_id_present)
                        {
                          clib_warning
                            ("Duplicate Client ID in received DHVPv6 message");
                          discard = 1;
                        }
                      else
                        {
                          u16 len = clib_net_to_host_u16 (option->length);
                          client_id_present = 1;
                          if (len != CLIENT_DUID_LENGTH ||
                              0 != memcmp (option->data,
                                           client_duid.bin_string,
                                           CLIENT_DUID_LENGTH))
                            {
                              clib_warning
                                ("Unrecognized client DUID inside received DHVPv6 message");
                              discard = 1;
                            }
                        }
                    }
                  else if (oo == DHCPV6_OPTION_SERVERID)
                    {
                      if (report.server_index != ~0)
                        {
                          clib_warning
                            ("Duplicate Server ID in received DHVPv6 message");
                          discard = 1;
                        }
                      else
                        {
                          u16 ol = clib_net_to_host_u16 (option->length);
                          if (ol - 2 /* 2 byte DUID type code */  > 128)
                            {
                              clib_warning
                                ("Server DUID (without type code) is longer than 128 octets");
                              discard = 1;
                            }
                          else
                            {
                              report.server_index =
                                server_index_get_or_create (option->data, ol);
                            }
                        }
                    }
                  else if (oo == DHCPV6_OPTION_PREFERENCE)
                    {
                      report.preference = option->data[0];
                    }
                  else if (oo == DHCPV6_OPTION_STATUS_CODE)
                    {
                      dhcpv6_status_code_t *sc = (void *) option;
                      report.status_code =
                        clib_net_to_host_u16 (sc->status_code);
                    }
                  options_length -=
                    sizeof (*option) + clib_net_to_host_u16 (option->length);
                  option =
                    (void *) ((u8 *) option + sizeof (*option) +
                              clib_net_to_host_u16 (option->length));
                }

              if (!client_id_present)
                {
                  clib_warning
                    ("Missing Client ID in received DHVPv6 message");
                  discard = 1;
                }
              if (report.server_index == ~0)
                {
                  clib_warning
                    ("Missing Server ID in received DHVPv6 message");
                  discard = 1;
                }

              if (!discard)
                {
                  if (!is_pd_packet)
                    {
                      address_report_t r;
                      r.body = report;
                      r.n_addresses = vec_len (addresses);
                      r.addresses = addresses;
                      dhcp6_publish_report (&r);
                      /* We just gave addresses to another process! */
                      addresses = 0;
                    }
                  else
                    {
                      prefix_report_t r;
                      r.body = report;
                      r.n_prefixes = vec_len (prefixes);
                      r.prefixes = prefixes;
                      dhcp6_pd_publish_report (&r);
                      /* We just gave prefixes to another process! */
                      prefixes = 0;
                    }
                }
              vec_free (addresses);
              vec_free (prefixes);

              break;
            default:
              break;
            }

          if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
            {
              dhcpv6_client_trace_t *t =
                vlib_add_trace (vm, node, b0, sizeof (*t));
            }

          /* 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);
    }

  return frame->n_vectors;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (dhcpv6_client_node, static) = {
    .function = dhcpv6_client_node_fn,
    .name = "dhcpv6-client",
    .vector_size = sizeof (u32),

    .n_errors = 0,

    .n_next_nodes = DHCPV6_CLIENT_N_NEXT,
    .next_nodes = {
  #define _(s,n) [DHCPV6_CLIENT_NEXT_##s] = n,
      foreach_dhcpv6_client
  #undef _
    },

    .format_trace = format_dhcpv6_client_trace,
};
/* *INDENT-ON* */

void
dhcp6_clients_enable_disable (u8 enable)
{
  vlib_main_t *vm = vlib_get_main ();

  if (enable)
    {
      if (client_duid.duid_type == 0)
        generate_client_duid ();
      udp_register_dst_port (vm, UDP_DST_PORT_dhcpv6_to_client,
                             dhcpv6_client_node.index, 0 /* is_ip6 */ );
    }
  else
    udp_unregister_dst_port (vm, UDP_DST_PORT_dhcpv6_to_client,
                             0 /* is_ip6 */ );
}

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