/*

 * Copyright (C) 2004, 2005, 2007-2009  Internet Systems Consortium, Inc. ("ISC")

 * Copyright (C) 2003  Internet Software Consortium.

 *

 * Permission to use, copy, modify, and/or distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH

 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY

 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,

 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM

 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE

 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR

 * PERFORMANCE OF THIS SOFTWARE.

 */

/* $Id: ifiter_getifaddrs.c,v 1.13 2009/09/24 23:48:13 tbox Exp $ */

/*! \file

 * \brief

 * Obtain the list of network interfaces using the getifaddrs(3) library.

 */

#include <ifaddrs.h>

/*% Iterator Magic */

#define IFITER_MAGIC    ISC_MAGIC('I', 'F', 'I', 'G')

/*% Valid Iterator */

#define VALID_IFITER(t)   ISC_MAGIC_VALID(t, IFITER_MAGIC)

#ifdef __linux

static isc_boolean_t seenv6 = ISC_FALSE;

#endif

/*% Iterator structure */

struct isc_interfaceiter {

  unsigned int    magic;    /*%< Magic number. */

  isc_mem_t   *mctx;

  void      *buf;   /*%< (unused) */

  unsigned int    bufsize;  /*%< (always 0) */

  struct ifaddrs    *ifaddrs; /*%< List of ifaddrs */

  struct ifaddrs    *pos;   /*%< Ptr to current ifaddr */

  isc_interface_t   current;  /*%< Current interface data. */

  isc_result_t    result;   /*%< Last result code. */

#ifdef  __linux

  FILE *                  proc;

  char                    entry[ISC_IF_INET6_SZ];

  isc_result_t            valid;

#endif

};

isc_result_t

isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {

  isc_interfaceiter_t *iter;

  isc_result_t result;

  char strbuf[ISC_STRERRORSIZE];

  int trys, ret;

  REQUIRE(mctx != NULL);

  REQUIRE(iterp != NULL);

  REQUIRE(*iterp == NULL);

  iter = isc_mem_get(mctx, sizeof(*iter));

  if (iter == NULL)

    return (ISC_R_NOMEMORY);

  iter->mctx = mctx;

  iter->buf = NULL;

  iter->bufsize = 0;

  iter->ifaddrs = NULL;

#ifdef __linux

  /*

   * Only open "/proc/net/if_inet6" if we have never seen a IPv6

   * address returned by getifaddrs().

   */

  if (!seenv6) {

    iter->proc = fopen("/proc/net/if_inet6", "r");

    if (iter->proc == NULL) {

      isc__strerror(errno, strbuf, sizeof(strbuf));

      isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,

              ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,

              "failed to open /proc/net/if_inet6");

    }

  } else

    iter->proc = NULL;

  iter->valid = ISC_R_FAILURE;

#endif

  /* If interrupted, try again */

  for (trys = 0; trys < 3; trys++) {

    if ((ret = getifaddrs(&iter->ifaddrs)) >= 0)

      break;

    if (errno != EINTR)

      break;

  }

  if (ret < 0) {

    isc__strerror(errno, strbuf, sizeof(strbuf));

    UNEXPECTED_ERROR(__FILE__, __LINE__,

                     "getting interface addresses: %s: %s",

         isc_msgcat_get(isc_msgcat,

            ISC_MSGSET_IFITERGETIFADDRS,

            ISC_MSG_GETIFADDRS,

            "getifaddrs"),

         strbuf);

    result = ISC_R_UNEXPECTED;

    goto failure;

  }

  /*

   * A newly created iterator has an undefined position

   * until isc_interfaceiter_first() is called.

   */

  iter->pos = NULL;

  iter->result = ISC_R_FAILURE;

  iter->magic = IFITER_MAGIC;

  *iterp = iter;

  return (ISC_R_SUCCESS);

 failure:

#ifdef __linux

  if (iter->proc != NULL)

    fclose(iter->proc);

#endif

  if (iter->ifaddrs != NULL) /* just in case */

    freeifaddrs(iter->ifaddrs);

  isc_mem_put(mctx, iter, sizeof(*iter));

  return (result);

}

/*

 * Get information about the current interface to iter->current.

 * If successful, return ISC_R_SUCCESS.

 * If the interface has an unsupported address family,

 * return ISC_R_IGNORE.

 */

static isc_result_t

internal_current(isc_interfaceiter_t *iter) {

  struct ifaddrs *ifa;

  int family;

  unsigned int namelen;

  REQUIRE(VALID_IFITER(iter));

  ifa = iter->pos;

#ifdef __linux

  /*

   * [Bug 2792]

   * burnicki: iter->pos is usually never NULL here (anymore?),

   * so linux_if_inet6_current(iter) is never called here.

   * However, that routine would check (under Linux), if the

   * interface is in a tentative state, e.g. if there's no link

   * yet but an IPv6 address has already be assigned.

   */

  if (iter->pos == NULL)

    return (linux_if_inet6_current(iter));

#endif

  INSIST(ifa != NULL);

  INSIST(ifa->ifa_name != NULL);

#ifdef IFF_RUNNING

  /*

   * [Bug 2792]

   * burnicki: if the interface is not running then

   * it may be in a tentative state. See above.

   */

  if ((ifa->ifa_flags & IFF_RUNNING) == 0)

    return (ISC_R_IGNORE);

#endif

  if (ifa->ifa_addr == NULL)

    return (ISC_R_IGNORE);

  family = ifa->ifa_addr->sa_family;

  if (family != AF_INET && family != AF_INET6)

    return (ISC_R_IGNORE);

#ifdef __linux

  if (family == AF_INET6)

    seenv6 = ISC_TRUE;

#endif

  memset(&iter->current, 0, sizeof(iter->current));

  namelen = strlen(ifa->ifa_name);

  if (namelen > sizeof(iter->current.name) - 1)

    namelen = sizeof(iter->current.name) - 1;

  memset(iter->current.name, 0, sizeof(iter->current.name));

  memcpy(iter->current.name, ifa->ifa_name, namelen);

  iter->current.flags = 0;

  if ((ifa->ifa_flags & IFF_UP) != 0)

    iter->current.flags |= INTERFACE_F_UP;

  if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0)

    iter->current.flags |= INTERFACE_F_POINTTOPOINT;

  if ((ifa->ifa_flags & IFF_LOOPBACK) != 0)

    iter->current.flags |= INTERFACE_F_LOOPBACK;

  if ((ifa->ifa_flags & IFF_BROADCAST) != 0)

    iter->current.flags |= INTERFACE_F_BROADCAST;

#ifdef IFF_MULTICAST

  if ((ifa->ifa_flags & IFF_MULTICAST) != 0)

    iter->current.flags |= INTERFACE_F_MULTICAST;

#endif

  iter->current.af = family;

  get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);

  if (ifa->ifa_netmask != NULL)

    get_addr(family, &iter->current.netmask, ifa->ifa_netmask,

       ifa->ifa_name);

  if (ifa->ifa_dstaddr != NULL &&

      (iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)

    get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,

       ifa->ifa_name);

  if (ifa->ifa_broadaddr != NULL &&

      (iter->current.flags & INTERFACE_F_BROADCAST) != 0)

    get_addr(family, &iter->current.broadcast, ifa->ifa_broadaddr,

       ifa->ifa_name);

#ifdef ISC_PLATFORM_HAVEIFNAMETOINDEX

  iter->current.ifindex = if_nametoindex(iter->current.name);

#endif

  return (ISC_R_SUCCESS);

}

/*

 * Step the iterator to the next interface.  Unlike

 * isc_interfaceiter_next(), this may leave the iterator

 * positioned on an interface that will ultimately

 * be ignored.  Return ISC_R_NOMORE if there are no more

 * interfaces, otherwise ISC_R_SUCCESS.

 */

static isc_result_t

internal_next(isc_interfaceiter_t *iter) {

  if (iter->pos != NULL)

    iter->pos = iter->pos->ifa_next;

  if (iter->pos == NULL) {

#ifdef __linux

    if (!seenv6)

      return (linux_if_inet6_next(iter));

#endif

    return (ISC_R_NOMORE);

  }

  return (ISC_R_SUCCESS);

}

static void

internal_destroy(isc_interfaceiter_t *iter) {

#ifdef __linux

  if (iter->proc != NULL)

    fclose(iter->proc);

  iter->proc = NULL;

#endif

  if (iter->ifaddrs)

    freeifaddrs(iter->ifaddrs);

  iter->ifaddrs = NULL;

}

static

void internal_first(isc_interfaceiter_t *iter) {

#ifdef __linux

  linux_if_inet6_first(iter);

#endif

  iter->pos = iter->ifaddrs;

}