ucblib/librpcsoc/get_myaddress.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * get_myaddress.c
 *
 * Get client's IP address via ioctl.  This avoids using the NIS.
 * Copyright (C) 1990, Sun Microsystems, Inc.
 */

#include <rpc/types.h>
#include <rpc/pmap_prot.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <stdio.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <syslog.h>
#include <malloc.h>
#include <unistd.h>
#include <stropts.h>
#include <stdlib.h>
#include <errno.h>

/*
 * don't use gethostbyname, which would invoke NIS
 */
void
get_myaddress(struct sockaddr_in *addr)
{
    int s;
    struct ifconf ifc;
    struct ifreq ifreq, *ifr;
    int len, numifs;
    int ret;

    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        syslog(LOG_ERR, "get_myaddress: socket: %m");
        exit(1);
    }

    do {
        ret = ioctl(s, SIOCGIFNUM, (char *)&numifs);
    } while (ret < 0 && (errno == EINTR || errno == EAGAIN));
    if (ret < 0) {
        syslog(LOG_ERR, "get_myaddress: ioctl: %m");
        exit(1);
    }

    ifc.ifc_len = numifs * sizeof (struct ifreq);
    if ((ifc.ifc_buf = (caddr_t)malloc(ifc.ifc_len)) == NULL) {
        syslog(LOG_ERR, "get_myaddress: malloc: %m");
        exit(1);
    }

    do {
        ret = ioctl(s, SIOCGIFCONF, (char *)&ifc);
    } while (ret < 0 && (errno == EINTR || errno == EAGAIN));
    if (ret < 0) {
        syslog(LOG_ERR,
            "get_myaddress: ioctl (get interface configuration): %m");
        exit(1);
    }

    /*
     * set default to loopback in case nothing is found.
     */
    addr->sin_family = AF_INET;
    addr->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    addr->sin_port = htons(PMAPPORT);

    ifr = ifc.ifc_req;
    for (len = ifc.ifc_len; len > 0; len -= sizeof (ifreq), ifr++) {
        ifreq = *ifr;
        do {
            ret = ioctl(s, SIOCGIFFLAGS, (char *)&ifreq);
        } while (ret < 0 && (errno == EINTR || errno == EAGAIN));
        if (ret < 0) {
            syslog(LOG_ERR, "get_myaddress: ioctl: %m");
            exit(1);
        }
        if (ifr->ifr_addr.sa_family != AF_INET)
            continue;
        if ((ifreq.ifr_flags & IFF_UP) == 0)
            continue;
        if (ifreq.ifr_flags & IFF_LOOPBACK)
            continue;
        if ((ifreq.ifr_flags & (IFF_MULTICAST | IFF_BROADCAST)) == 0)
            continue;
        *addr = *((struct sockaddr_in *)&ifr->ifr_addr);
        addr->sin_port = htons(PMAPPORT);
        break;
    }
    free(ifc.ifc_buf);
    (void) close(s);
}