/*

 * Neighbor Discovery snooping for Proxy ARP

 * Copyright (c) 2014, Qualcomm Atheros, Inc.

 *

 * This software may be distributed under the terms of the BSD license.

 * See README for more details.

 */

#include "utils/includes.h"

#include <netinet/ip6.h>

#include <netinet/icmp6.h>

#include "utils/common.h"

#include "l2_packet/l2_packet.h"

#include "hostapd.h"

#include "sta_info.h"

#include "ap_drv_ops.h"

#include "list.h"

#include "x_snoop.h"

#include "ndisc_snoop.h"

struct ip6addr {

  struct in6_addr addr;

  struct dl_list list;

};

struct icmpv6_ndmsg {

  struct ip6_hdr ipv6h;

  struct icmp6_hdr icmp6h;

  struct in6_addr target_addr;

  u8 opt_type;

  u8 len;

  u8 opt_lladdr[0];

} STRUCT_PACKED;

#define ROUTER_ADVERTISEMENT  134

#define NEIGHBOR_SOLICITATION 135

#define NEIGHBOR_ADVERTISEMENT  136

#define SOURCE_LL_ADDR    1

static int sta_ip6addr_add(struct sta_info *sta, struct in6_addr *addr)

{

  struct ip6addr *ip6addr;

  ip6addr = os_zalloc(sizeof(*ip6addr));

  if (!ip6addr)

    return -1;

  os_memcpy(&ip6addr->addr, addr, sizeof(*addr));

  dl_list_add_tail(&sta->ip6addr, &ip6addr->list);

  return 0;

}

void sta_ip6addr_del(struct hostapd_data *hapd, struct sta_info *sta)

{

  struct ip6addr *ip6addr, *prev;

  dl_list_for_each_safe(ip6addr, prev, &sta->ip6addr, struct ip6addr,

            list) {

    hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &ip6addr->addr);

    dl_list_del(&ip6addr->list);

    os_free(ip6addr);

  }

}

static int sta_has_ip6addr(struct sta_info *sta, struct in6_addr *addr)

{

  struct ip6addr *ip6addr;

  dl_list_for_each(ip6addr, &sta->ip6addr, struct ip6addr, list) {

    if (ip6addr->addr.s6_addr32[0] == addr->s6_addr32[0] &&

        ip6addr->addr.s6_addr32[1] == addr->s6_addr32[1] &&

        ip6addr->addr.s6_addr32[2] == addr->s6_addr32[2] &&

        ip6addr->addr.s6_addr32[3] == addr->s6_addr32[3])

      return 1;

  }

  return 0;

}

static void ucast_to_stas(struct hostapd_data *hapd, const u8 *buf, size_t len)

{

  struct sta_info *sta;

  for (sta = hapd->sta_list; sta; sta = sta->next) {

    if (!(sta->flags & WLAN_STA_AUTHORIZED))

      continue;

    x_snoop_mcast_to_ucast_convert_send(hapd, sta, (u8 *) buf, len);

  }

}

static void handle_ndisc(void *ctx, const u8 *src_addr, const u8 *buf,

       size_t len)

{

  struct hostapd_data *hapd = ctx;

  struct icmpv6_ndmsg *msg;

  struct in6_addr saddr;

  struct sta_info *sta;

  int res;

  char addrtxt[INET6_ADDRSTRLEN + 1];

  if (len < ETH_HLEN + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))

    return;

  msg = (struct icmpv6_ndmsg *) &buf[ETH_HLEN];

  switch (msg->icmp6h.icmp6_type) {

  case NEIGHBOR_SOLICITATION:

    if (len < ETH_HLEN + sizeof(*msg))

      return;

    if (msg->opt_type != SOURCE_LL_ADDR)

      return;

    /*

     * IPv6 header may not be 32-bit aligned in the buffer, so use

     * a local copy to avoid unaligned reads.

     */

    os_memcpy(&saddr, &msg->ipv6h.ip6_src, sizeof(saddr));

    if (!(saddr.s6_addr32[0] == 0 && saddr.s6_addr32[1] == 0 &&

          saddr.s6_addr32[2] == 0 && saddr.s6_addr32[3] == 0)) {

      if (len < ETH_HLEN + sizeof(*msg) + ETH_ALEN)

        return;

      sta = ap_get_sta(hapd, msg->opt_lladdr);

      if (!sta)

        return;

      if (sta_has_ip6addr(sta, &saddr))

        return;

      if (inet_ntop(AF_INET6, &saddr, addrtxt,

              sizeof(addrtxt)) == NULL)

        addrtxt[0] = '\0';

      wpa_printf(MSG_DEBUG, "ndisc_snoop: Learned new IPv6 address %s for "

           MACSTR, addrtxt, MAC2STR(sta->addr));

      hostapd_drv_br_delete_ip_neigh(hapd, 6, (u8 *) &saddr);

      res = hostapd_drv_br_add_ip_neigh(hapd, 6,

                (u8 *) &saddr,

                128, sta->addr);

      if (res) {

        wpa_printf(MSG_ERROR,

             "ndisc_snoop: Adding ip neigh failed: %d",

             res);

        return;

      }

      if (sta_ip6addr_add(sta, &saddr))

        return;

    }

    break;

#ifdef CONFIG_HS20

  case ROUTER_ADVERTISEMENT:

    if (hapd->conf->disable_dgaf)

      ucast_to_stas(hapd, buf, len);

    break;

#endif /* CONFIG_HS20 */

  case NEIGHBOR_ADVERTISEMENT:

    if (hapd->conf->na_mcast_to_ucast)

      ucast_to_stas(hapd, buf, len);

    break;

  default:

    break;

  }

}

int ndisc_snoop_init(struct hostapd_data *hapd)

{

  hapd->sock_ndisc = x_snoop_get_l2_packet(hapd, handle_ndisc,

             L2_PACKET_FILTER_NDISC);

  if (hapd->sock_ndisc == NULL) {

    wpa_printf(MSG_DEBUG,

         "ndisc_snoop: Failed to initialize L2 packet processing for NDISC packets: %s",

         strerror(errno));

    return -1;

  }

  return 0;

}

void ndisc_snoop_deinit(struct hostapd_data *hapd)

{

  l2_packet_deinit(hapd->sock_ndisc);

  hapd->sock_ndisc = NULL;

}