/*
Copyright (c) 2007, Adobe Systems, Incorporated
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.

* Neither the name of Adobe Systems, Network Resonance nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <csi_platform.h>
#include <assert.h>
#include <string.h>

#ifdef WIN32
#include "addrs-win32.h"
#elif defined(BSD) || defined(DARWIN)
#include "addrs-bsd.h"
#else
#include "addrs-netlink.h"
#endif

#include "stun.h"
#include "addrs.h"
#include "util.h"

static int
nr_stun_is_duplicate_addr(nr_local_addr addrs[], int count, nr_local_addr *addr)
{
    int i;
    int different;

    for (i = 0; i < count; ++i) {
        different = nr_transport_addr_cmp(&addrs[i].addr, &(addr->addr),
          NR_TRANSPORT_ADDR_CMP_MODE_ALL);
        if (!different)
            return 1;  /* duplicate */
    }

    return 0;
}

static int
nr_stun_filter_find_first_addr_with_ifname(nr_local_addr addrs[], int count, const char *ifname) {
  for (int i = 0; i < count; ++i) {
    if (!strncmp(addrs[i].addr.ifname, ifname, sizeof(addrs[i].addr.ifname))) {
      return i;
    }
  }
  return count;
}

static int
nr_stun_filter_addrs_for_ifname(nr_local_addr src[], const int src_begin, const int src_end, nr_local_addr dest[], int *dest_index, int remove_loopback, int remove_link_local) {
  int r, _status;
  /* We prefer temp ipv6 for their privacy properties. If we cannot get
   * that, we prefer ipv6 that are not based on mac address. */
  int filter_mac_ipv6 = 0;
  int filter_teredo_ipv6 = 0;
  int filter_non_temp_ipv6 = 0;

  const char* ifname = src[src_begin].addr.ifname;

  /* Figure out what we want to filter */
  for (int i = src_begin; i < src_end; ++i) {
    if (strncmp(ifname, src[i].addr.ifname, sizeof(src[i].addr.ifname))) {
      /* Ignore addrs from other interfaces */
      continue;
    }

    if (src[i].addr.ip_version == NR_IPV6) {
      if (nr_transport_addr_is_teredo(&src[i].addr)) {
          src[i].interface.type |= NR_INTERFACE_TYPE_TEREDO;
          /* Prefer teredo over mac-based address. Probably will never see
           * both. */
          filter_mac_ipv6 = 1;
      } else {
        filter_teredo_ipv6 = 1;
      }

      if (!nr_transport_addr_is_mac_based(&src[i].addr)) {
        filter_mac_ipv6 = 1;
      }

      if (src[i].flags & NR_ADDR_FLAG_TEMPORARY) {
        filter_non_temp_ipv6 = 1;
      }
    }
  }

  /* Perform the filtering */
  for (int i = src_begin; i < src_end; ++i) {
    if (strncmp(ifname, src[i].addr.ifname, sizeof(src[i].addr.ifname))) {
      /* Ignore addrs from other interfaces */
      r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring addr from interface other than %s", ifname);
      continue;
    }

    if (nr_stun_is_duplicate_addr(dest, *dest_index, &src[i])) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring duplicate addr");
        /* skip src[i], it's a duplicate */
    }
    else if (remove_loopback && nr_transport_addr_is_loopback(&src[i].addr)) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring loopback addr");
        /* skip src[i], it's a loopback */
    }
    else if (remove_link_local &&
             nr_transport_addr_is_link_local(&src[i].addr)) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring link local addr");
        /* skip src[i], it's a link-local address */
    }
    else if (filter_mac_ipv6 &&
             nr_transport_addr_is_mac_based(&src[i].addr)) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring MAC-based addr");
        /* skip src[i], it's MAC based */
    }
    else if (filter_teredo_ipv6 &&
             nr_transport_addr_is_teredo(&src[i].addr)) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring teredo addr");
        /* skip src[i], it's a Teredo address */
    }
    else if (filter_non_temp_ipv6 &&
             (src[i].addr.ip_version == NR_IPV6) &&
             !(src[i].flags & NR_ADDR_FLAG_TEMPORARY)) {
        r_log(NR_LOG_STUN, LOG_WARNING, "Ignoring non-temp addr (we have at least one temp addr)");
        /* skip src[i], it's a non-temporary ipv6, and we have a temporary */
    }
    else {
        /* otherwise, copy it to the destination array */
        if ((r=nr_local_addr_copy(&dest[*dest_index], &src[i])))
            ABORT(r);
        ++(*dest_index);
    }
  }

  _status = 0;
abort:
  return _status;
}

int
nr_stun_filter_addrs(nr_local_addr addrs[], int remove_loopback, int remove_link_local, int *count)
{
    int r, _status;
    nr_local_addr *tmp = 0;
    int dest_index = 0;

    tmp = RMALLOC(*count * sizeof(*tmp));
    if (!tmp)
        ABORT(R_NO_MEMORY);

    for (int i = 0; i < *count; ++i) {
      if (i == nr_stun_filter_find_first_addr_with_ifname(addrs, *count, addrs[i].addr.ifname)) {
        /* This is the first address associated with this interface.
         * Filter for this interface once, now. */
        if (r = nr_stun_filter_addrs_for_ifname(addrs, i, *count, tmp, &dest_index, remove_loopback, remove_link_local)) {
          ABORT(r);
        }
      }
    }

    /* Clear the entire array out before copying back */
    memset(addrs, 0, *count * sizeof(*addrs));

    *count = dest_index;

    /* copy temporary array into passed in/out array */
    for (int i = 0; i < *count; ++i) {
        if ((r=nr_local_addr_copy(&addrs[i], &tmp[i])))
            ABORT(r);
    }

    _status = 0;
  abort:
    RFREE(tmp);
    return _status;
}

#ifndef USE_PLATFORM_NR_STUN_GET_ADDRS

int
nr_stun_get_addrs(nr_local_addr addrs[], int maxaddrs, int *count)
{
    int _status=0;
    int i;
    char typestr[100];

    // Ensure output records are always fully defined.  See bug 1589990.
    if (maxaddrs > 0) {
       memset(addrs, 0, maxaddrs * sizeof(nr_local_addr));
    }

    _status = stun_getaddrs_filtered(addrs, maxaddrs, count);

    for (i = 0; i < *count; ++i) {
      nr_local_addr_fmt_info_string(addrs+i,typestr,sizeof(typestr));
      r_log(NR_LOG_STUN, LOG_DEBUG, "Address %d: %s on %s, type: %s\n",
            i,addrs[i].addr.as_string,addrs[i].addr.ifname,typestr);
    }

    return _status;
}

#endif