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/*
* Copyright (c) 2000
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* $FreeBSD$
*/
/* XXX Yes this is WAY too complicated */
#ifndef lint
static const char rcsid[] =
"@(#) $Id: findsaddr-socket.c,v 1.1 2000/11/23 20:17:12 leres Exp $ (LBL)";
#endif
#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h> /* concession to AIX */
#if __STDC__
struct mbuf;
struct rtentry;
#endif
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "gnuc.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#include "findsaddr.h"
#ifdef HAVE_SOCKADDR_SA_LEN
#define SALEN(sa) ((sa)->sa_len)
#else
#define SALEN(sa) salen(sa)
#endif
#ifndef roundup
#define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
#endif
struct rtmsg {
struct rt_msghdr rtmsg;
u_char data[512];
};
static struct rtmsg rtmsg = {
{ 0, RTM_VERSION, RTM_GET, 0,
RTF_UP | RTF_GATEWAY | RTF_HOST | RTF_STATIC,
RTA_DST | RTA_IFA, 0, 0, 0, 0, 0, { 0 } },
{ 0 }
};
#ifndef HAVE_SOCKADDR_SA_LEN
static int salen(struct sockaddr *);
#endif
/*
* Return the source address for the given destination address
*/
const char *
findsaddr(register const struct sockaddr_in *to,
register struct sockaddr_in *from)
{
register struct rt_msghdr *rp;
register u_char *cp;
register struct sockaddr_in *sp, *ifa;
register struct sockaddr *sa;
register int s, size, cc, seq, i;
register pid_t pid;
static char errbuf[512];
s = socket(PF_ROUTE, SOCK_RAW, AF_UNSPEC);
if (s < 0) {
sprintf(errbuf, "socket: %.128s", strerror(errno));
return (errbuf);
}
seq = 0;
pid = getpid();
rp = &rtmsg.rtmsg;
rp->rtm_seq = ++seq;
cp = (u_char *)(rp + 1);
sp = (struct sockaddr_in *)cp;
*sp = *to;
cp += roundup(SALEN((struct sockaddr *)sp), sizeof(u_int32_t));
size = cp - (u_char *)rp;
rp->rtm_msglen = size;
cc = write(s, (char *)rp, size);
if (cc < 0) {
sprintf(errbuf, "write: %.128s", strerror(errno));
close(s);
return (errbuf);
}
if (cc != size) {
sprintf(errbuf, "short write (%d != %d)", cc, size);
close(s);
return (errbuf);
}
size = sizeof(rtmsg);
do {
memset(rp, 0, size);
cc = read(s, (char *)rp, size);
if (cc < 0) {
sprintf(errbuf, "read: %.128s", strerror(errno));
close(s);
return (errbuf);
}
} while (rp->rtm_seq != seq || rp->rtm_pid != pid);
close(s);
if (rp->rtm_version != RTM_VERSION) {
sprintf(errbuf, "bad version %d", rp->rtm_version);
return (errbuf);
}
if (rp->rtm_msglen > cc) {
sprintf(errbuf, "bad msglen %d > %d", rp->rtm_msglen, cc);
return (errbuf);
}
if (rp->rtm_errno != 0) {
sprintf(errbuf, "rtm_errno: %.128s", strerror(rp->rtm_errno));
return (errbuf);
}
/* Find the interface sockaddr */
cp = (u_char *)(rp + 1);
for (i = 1; i != 0; i <<= 1)
if ((i & rp->rtm_addrs) != 0) {
sa = (struct sockaddr *)cp;
switch (i) {
case RTA_IFA:
if (sa->sa_family == AF_INET) {
ifa = (struct sockaddr_in *)cp;
if (ifa->sin_addr.s_addr != 0) {
*from = *ifa;
return (NULL);
}
}
break;
}
if (SALEN(sa) == 0)
cp += sizeof(long);
else
cp += roundup(SALEN(sa), sizeof(long));
}
return ("failed!");
}
#ifndef HAVE_SOCKADDR_SA_LEN
static int
salen(struct sockaddr *sa)
{
switch (sa->sa_family) {
case AF_INET:
return (sizeof(struct sockaddr_in));
case AF_LINK:
return (sizeof(struct sockaddr_dl));
default:
return (sizeof(struct sockaddr));
}
}
#endif
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