pjlib/src/pj/addr_resolv_sock.c

/* $Id$ */
/* 
 * Copyright (C)2003-2007 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include <pj/addr_resolv.h>
#include <pj/assert.h>
#include <pj/string.h>
#include <pj/errno.h>
#include <pj/compat/socket.h>


PJ_DEF(pj_status_t) pj_gethostbyname(const pj_str_t *hostname, pj_hostent *phe)
{
    struct hostent *he;
    char copy[PJ_MAX_HOSTNAME];

    pj_assert(hostname && hostname ->slen < PJ_MAX_HOSTNAME);
    
    if (hostname->slen >= PJ_MAX_HOSTNAME)
	return PJ_ENAMETOOLONG;

    pj_memcpy(copy, hostname->ptr, hostname->slen);
    copy[ hostname->slen ] = '\0';

    he = gethostbyname(copy);
    if (!he) {
	return pj_get_netos_error();
    }

    phe->h_name = he->h_name;
    phe->h_aliases = he->h_aliases;
    phe->h_addrtype = he->h_addrtype;
    phe->h_length = he->h_length;
    phe->h_addr_list = he->h_addr_list;

    return PJ_SUCCESS;
}

/* Resolve the IP address of local machine */
pj_status_t pj_gethostip(pj_in_addr *addr)
{
    const pj_str_t *hostname = pj_gethostname();
    struct pj_hostent he;
    pj_str_t cp;
    pj_in_addr loopip;
    pj_status_t status;

    cp = pj_str("127.0.0.1");
    loopip = pj_inet_addr(&cp);

#ifdef _MSC_VER
    /* Get rid of "uninitialized he variable" with MS compilers */
    pj_bzero(&he, sizeof(he));
#endif

    /* Try with resolving local hostname first */
    status = pj_gethostbyname(hostname, &he);
    if (status == PJ_SUCCESS) {
	*addr = *(pj_in_addr*)he.h_addr;
    }


    /* If we end up with 127.0.0.1, resolve the IP by getting the default
     * interface to connect to some public host.
     */
    if (status != PJ_SUCCESS || addr->s_addr == loopip.s_addr) {
	pj_sock_t fd;
	pj_sockaddr_in a;
	int len;

	status = pj_sock_socket(PJ_AF_INET, PJ_SOCK_DGRAM, 0, &fd);
	if (status != PJ_SUCCESS) {
	    return status;
	}

	cp = pj_str("1.1.1.1");
	pj_sockaddr_in_init(&a, &cp, 53);

	status = pj_sock_connect(fd, &a, sizeof(a));
	if (status != PJ_SUCCESS) {
	    pj_sock_close(fd);
	    /* Return 127.0.0.1 as the address */
	    return PJ_SUCCESS;
	}

	len = sizeof(a);
	status = pj_sock_getsockname(fd, &a, &len);
	if (status != PJ_SUCCESS) {
	    pj_sock_close(fd);
	    /* Return 127.0.0.1 as the address */
	    return PJ_SUCCESS;
	}

	pj_sock_close(fd);

	*addr = a.sin_addr;
    }

    return status;
}