su_localinfo.c

Internet Phone, Chat, Conferencing

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2005 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

/**@ingroup su_socket
 * @CFILE su_localinfo.c
 *
 * Obtain list of local addresses.
 *
 * @author Pekka Pessi <[e-mail]>
 * 
 * @date Created: Wed Oct  4 14:09:29 EET 2000 ppessi
 */

#include "config.h"

#include "sofia-sip/su.h"
#include "sofia-sip/su_localinfo.h"
#include "su_module_debug.h"

#if HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stddef.h>
#include <sys/types.h>

#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#if HAVE_NET_IF_H
#include <net/if.h>
#endif
#if HAVE_NET_IF_TYPES_H
#include <net/if_types.h>
#endif

#if HAVE_GETIFADDRS

#define USE_LOCALINFO0 1
#define localinfo0 bsd_localinfo
static int bsd_localinfo(su_localinfo_t const *, su_localinfo_t **);

#elif HAVE_IPHLPAPI_H

#include <iphlpapi.h>
#define USE_LOCALINFO0 1
#define localinfo0 win_localinfo
static int win_localinfo(su_localinfo_t const *, su_localinfo_t **);

#else

#undef USE_LOCALINFO0
static int localinfo4(su_localinfo_t const *, su_localinfo_t **);
#  if SU_HAVE_IN6
static int localinfo6(su_localinfo_t const *, su_localinfo_t **);
#  endif

#endif

static int li_name(su_localinfo_t const*, int, su_sockaddr_t const*, char **);
static void li_sort(su_localinfo_t *i, su_localinfo_t **rresult);
static int li_scope4(uint32_t ip4);

/** @brief Request local address information.
 *
 * The function su_getlocalinfo() gathers the network interfaces and the
 * addresses corresponding to them, checks if they match to the search
 * criteria specifed by @a hints and returns a list of matching local
 * address information in the @a res. The local address information may
 * include IPv4/IPv6 addresses, interface name, interface index, address
 * scope, and domain names corresponding to the local addresses.
 *
 * @param hints specifies selection criteria
 * @param return_localinfo   return list of local addresses
 *
 * @par Selection criteria - hints
 *
 * The selection criteria @a hints is used to select which addresses are
 * returned and what kind of information is included in the @a res list.
 *
 * @par Selection by flags - hints->li_flags
 *
 * The @a hints->li_flags contain flags, which can be combined with bit-wise
 * or.  The currently defined flags are as follows:
 *
 * - @c LI_V4MAPPED: when returning IPv4 addresses, map them as IPv6
 *   addresses.  If this flag is specified, IPv4 addresses are returned even
 *   if @a hints->li_family is set to @c AF_INET6.
 * - @c LI_CANONNAME: return the domain name (DNS PTR) corresponding to the 
 *   local address in @a li_canonname.
 * - @c LI_NAMEREQD: Do not return addresses not in DNS. 
 * - @c LI_NUMERIC: instead of domain name, return the text presentation of
 *   the addresss in @a li_canonname.
 * - @c LI_IFNAME: return the interface name in @a li_ifname.
 *
 * @par Selection by address family - hints->li_family
 *
 * The address family can have three values: 0, AF_INET and AF_INET6.  If
 * address family @a hints->li_family, both IPv4 and IPv6 addresses are
 * returned.
 *
 * @par Selection by interface index - hints->li_index
 *
 * If the field @a hints->li_index is non-zero, only the addresses assigned
 * to the interface with given index are returned.  The list of interface
 * indices and names can be obtained by the function @c su_if_names().
 *
 * @par Selection by interface name - hints->li_ifname
 *
 * If the field @a hints->li_ifname is not NULL, only the addresses assigned
 * to the named interface are returned.  The list of interface names can be
 * obtained by the function @c su_if_names().
 *
 * @par Selection by address scope - hints->li_scope
 *
 * If the field @a hints->li_scope is nonzero, only the addresses with
 * matching scope are returned.  The address scopes can be combined with
 * bitwise or. For instance, setting @a hints->li_scope to @c
 * LI_SCOPE_GLOBAL | @c LI_SCOPE_SITE, both the @e global and @e site-local
 * addresses are returned.
 *
 * @par 
 * For IPv4, the loopback addresses (addresses in the net 127) are currently
 * considered @e host-local, other addresses are @e global.
 *
 * @par Selection by domain name - hints->li_canonname
 *
 * If this field is non-null, the domain name (DNS PTR) corresponding to
 * local IP addresses should match to the name given in this field.
 *
 * @return 
 * The function su_getlocalinfo() returns zero when successful, or
 * negative error code when failed.
 * 
 * @par diagnostics
 * The function su_gli_strerror() returns a string describing the error code
 * returned by su_getlocalinfo().
 *
 */
int su_getlocalinfo(su_localinfo_t const *hints, 
		    su_localinfo_t **return_localinfo)
{
  int error = 0, ip4 = 0, ip6 = 0;
  su_localinfo_t *result = NULL, **rr = &result;
  su_localinfo_t hh[1] = {{ 0 }};

  assert(return_localinfo);

  *return_localinfo = NULL;

  if (hints) {
    /* Copy hints so that it can be modified */
    *hh = *hints;
    if (hh->li_canonname)
      hh->li_flags |= LI_CANONNAME;
    if ((hh->li_flags & LI_IFNAME) && hh->li_ifname == NULL)
      return ELI_BADHINTS;
  }

  switch (hh->li_family) {
#if SU_HAVE_IN6
  case AF_INET6:
    if (hh->li_flags & LI_V4MAPPED)
      ip6 = ip4 = 1, hh->li_family = 0;
    else
      ip6 = 1;
    break;
#endif

  case AF_INET:
    ip4 = 1;
    break;

  case 0:
    ip6 = ip4 = 1;    
    break;

  default:
    return -1;
  }

#if USE_LOCALINFO0 
  error = localinfo0(hh, rr);
#else

#  if SU_HAVE_IN6
  if (ip6) {
    error = localinfo6(hh, rr);
    if (error == ELI_NOADDRESS && ip4)
      error = 0;
    
    if (!error) 
      /* Search end of list */
      for (; *rr; rr = &(*rr)->li_next)
	;
  }
#  endif
  if (ip4 && !error) {
    /* Append IPv4 addresses */
    error = localinfo4(hh, rr);
  }
#endif

  if (!result)
    error = ELI_NOADDRESS;

  if (!error)
    li_sort(result, return_localinfo);
  else
    su_freelocalinfo(result);

  return error;
}

/** Free local address information. */
void su_freelocalinfo(su_localinfo_t *tbf)
{
  su_localinfo_t *li;

  for (li = tbf; li; li = tbf) {
    tbf = li->li_next;
    if (li->li_canonname)
      free(li->li_canonname);
    free(li);
  }
}

/** Describe su_localinfo errors. 
 *
 * The function su_gli_strerror() returns a string describing the error
 * condition indicated by the code that was returned by the function
 * su_getlocalinfo().
 *
 * @param error error code returned by su_getlocalinfo()
 *
 * @return
 * A pointer to string describing the error condition.
 */
char const *su_gli_strerror(int error)
{
  switch (error) {
  case ELI_NOERROR:   return "No error";
  case ELI_NOADDRESS: return "No matching address";
  case ELI_MEMORY:    return "Memory allocation error";
  case ELI_FAMILY:    return "Unknown address family";
  case ELI_RESOLVER:  return "Error when resolving address";
  case ELI_SYSTEM:    return "System error";
  case ELI_BADHINTS:  return "Invalid value for hints";
  default:            return "Unknown error";
  }
}

/** Duplicate su_localinfo structure.
 */
su_localinfo_t *su_copylocalinfo(su_localinfo_t const *li0)
{
  int n;
  su_localinfo_t *li, *retval = NULL, **lli = &retval;

# define SLEN(s) ((s) ? strlen(s) + 1 : 0)

  for (; li0 ; li0 = li0->li_next) {
    n = sizeof(*li0) + li0->li_addrlen + SLEN(li0->li_ifname);
    if (!(li = calloc(1, n))) {
      su_freelocalinfo(retval);
      return NULL;
    }
    *lli = li;
    lli = &li->li_next;
    li->li_flags = li0->li_flags;
    li->li_family = li0->li_family;
    li->li_index = li0->li_index;
    li->li_scope = li0->li_scope;
    li->li_addrlen = li0->li_addrlen;
    li->li_addr = memcpy(li + 1, li0->li_addr, li0->li_addrlen);

    if (li0->li_canonname) {
      if (!(li->li_canonname = malloc(SLEN(li0->li_canonname)))) {
	su_freelocalinfo(retval);
	return NULL;
      }
      strcpy(li->li_canonname, li0->li_canonname);
    }

    if (li0->li_ifname)
      li->li_ifname = strcpy(li->li_addrlen + (char *)li->li_addr, 
			     li0->li_ifname);
  }

  return retval;
}


/** Return IPv4 address scope */
static int 
li_scope4(uint32_t ip4)
{
  ip4 = ntohl(ip4);

  if (0x7f000000 == (ip4 & 0xff000000))
    return LI_SCOPE_HOST;
  /* draft-ietf-zeroconf-ipv4-linklocal-02.txt - 169.254/16. */
  else if (0xa9fe0000 == (ip4 & 0xffff0000))
    return LI_SCOPE_LINK;
  /* RFC1918 - 10/8, 172.16/12, 192.168/16. */
  else if (0x0a000000 == (ip4 & 0xff000000) ||
	   0xac100000 == (ip4 & 0xfff00000) ||
	   0xc0a80000 == (ip4 & 0xffff0000))
    return LI_SCOPE_SITE;
  else
    return LI_SCOPE_GLOBAL;
}

#if USE_LOCALINFO0
/** Return IPv6 address scope */
static int 
li_scope6(struct in6_addr const *ip6)
{
  if (IN6_IS_ADDR_V4MAPPED(ip6) || IN6_IS_ADDR_V4COMPAT(ip6)) {
    uint32_t ip4 = *(uint32_t *)(ip6->s6_addr + 12);
    return li_scope4(ip4);
  }
  else if (IN6_IS_ADDR_LOOPBACK(ip6))
    return LI_SCOPE_HOST;
  else if (IN6_IS_ADDR_LINKLOCAL(ip6))
    return LI_SCOPE_LINK;
  else if (IN6_IS_ADDR_SITELOCAL(ip6))
    return LI_SCOPE_SITE;
  else
    return LI_SCOPE_GLOBAL;
}

#elif HAVE_IFCONF
/** Build a list of local IPv4 addresses and append it to *rresult. */
static
int localinfo4(su_localinfo_t const *hints, su_localinfo_t **rresult)
{
  su_localinfo_t *tbf = NULL, **lli = &tbf;
  su_localinfo_t *li = NULL, *li_first = NULL;
  su_sockaddr_t *su;
  int error = ELI_NOADDRESS;
  char *canonname = NULL;
  su_socket_t s;

#if SU_HAVE_IN6
  int su_xtra = (hints->li_flags & LI_V4MAPPED) ? sizeof(*su) : 0;
#else
  int const su_xtra = 0;
#endif

  struct ifconf ifc;
  int numifs;
  char *buffer;
  struct ifreq *ifr, *ifr_next;

  s = su_socket(AF_INET, SOCK_DGRAM, 0);
  if (s == -1) {
    SU_DEBUG_1(("su_localinfo: su_socket failed: %s\n", 
		su_strerror(su_errno())));
    return ELI_SYSTEM;
  }

#if defined(__APPLE_CC__)
  {
    su_sockaddr_t *sa;
    unsigned int salen = sizeof(*sa);
    int scope = 0, gni_flags = 0;

    li = calloc(1, sizeof(su_localinfo_t));
    sa = calloc(1, sizeof(su_sockaddr_t));

    error = getsockname(s, (struct sockaddr *) sa, &salen);
    if (error < 0 && errno == SOCKET_ERROR) {
      SU_DEBUG_1(("%s: getsockname() failed: %s\n", __func__,
		  su_strerror(su_errno())));
    }

    error = bind(s, (struct sockaddr *) sa, salen);

    if (error < 0) {
      SU_DEBUG_1(("%s: bind() failed: %s\n", __func__,
		  su_strerror(su_errno())));
      goto err;
    }

    su_close(s);

    scope = li_scope4(sa->su_sin.sin_addr.s_addr);

    if (scope == LI_SCOPE_HOST || scope == LI_SCOPE_LINK)
      gni_flags = NI_NUMERICHOST;
    
    if (su_xtra) {
      /* Map IPv4 address to IPv6 address */
      memset(sa, 0, sizeof(*sa));
      sa->su_family = AF_INET6;
      ((int32_t*)&sa->su_sin6.sin6_addr)[3] = sa->su_sin.sin_addr.s_addr;
      ((int32_t*)&sa->su_sin6.sin6_addr)[2] = htonl(0xffff);
    }

    li->li_family = sa->su_family;
    li->li_scope = scope;
    li->li_index = 0;
    li->li_addrlen = su_sockaddr_size(sa);
    li->li_addr = sa;

    if ((error = li_name(hints, gni_flags, sa, &canonname)) < 0)
      goto err;

    if (canonname) {
      if (strchr(canonname, ':') ||
	  strspn(canonname, "0123456789.") == strlen(canonname))
	    li->li_flags |= LI_NUMERIC;
    }
    else
      li->li_flags = 0;

    li->li_canonname = canonname;

    canonname = NULL;

    *rresult = li;
    return 0;
  }
#endif


# if HAVE_IFNUM
  /* Get the list of known IP address from the kernel */
  if (ioctl(s, SIOCGIFNUM, (char *) &numifs) < 0) {
    /* can't get number of interfaces -- fall back */
    SU_DEBUG_1(("su_localinfo: SIOCGIFNUM failed: %s\n", 
		su_strerror(su_errno())));
    error = ELI_SYSTEM;
    goto err;
  }

  SU_DEBUG_9(("su_localinfo: %d active interfaces according to SIOCGIFNUM\n", 
	      numifs));

  if (numifs < 0)
# endif
    /* Default to 64 interfaces. Enough? */
    numifs = 64;

  if (numifs == 0)
    return 0;

  /*
   * Allocate memory for SIOCGIFCONF ioctl buffer. This memory block is also
   * used as li_first, first localinfo struct that is returned, so it can be
   * freed by freelocalinfo() without any complications.
   */
  ifc.ifc_len = numifs * sizeof (struct ifreq);
  buffer = malloc(sizeof(su_localinfo_t) + ifc.ifc_len + su_xtra);
  if (!buffer) {
    SU_DEBUG_1(("su_localinfo: memory exhausted\n"));
    error = ELI_MEMORY;
    goto err;
  }

  li_first = (su_localinfo_t *)buffer;