NetBSD-5.0.2/usr.sbin/rarpd/mkarp.c
/* $NetBSD: mkarp.c,v 1.7 2008/07/21 13:36:59 lukem Exp $ */
/*
* Copyright (c) 1984, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Sun Microsystems, Inc.
*
* 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. Neither the name of the University nor the names of its contributors
* 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1984, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95";
#else
__RCSID("$NetBSD: mkarp.c,v 1.7 2008/07/21 13:36:59 lukem Exp $");
#endif
#endif /* not lint */
/*
* mkarp - set an arp table entry
*/
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_ether.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_inarp.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#include <netdb.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "mkarp.h"
/* Roundup the same way rt_xaddrs does */
#define ROUNDUP(a) \
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
int rtmsg(int, int, struct rt_msghdr *, struct sockaddr_inarp *,
struct sockaddr_dl *);
struct {
struct rt_msghdr m_rtm;
char m_space[512];
} m_rtmsg;
/*
* Set an individual arp entry
*/
int
mkarp(u_char *haddr, u_int32_t ipaddr)
{
static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET };
static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK };
struct sockaddr_inarp *sin;
struct sockaddr_dl *sdl;
struct rt_msghdr *rtm;
u_int8_t *p, *endp;
int result;
int s;
struct sockaddr_inarp sin_m;
struct sockaddr_dl sdl_m;
sin = &sin_m;
rtm = &(m_rtmsg.m_rtm);
sdl_m = blank_sdl; /* struct copy */
sin_m = blank_sin; /* struct copy */
sin->sin_addr.s_addr = ipaddr;
p = LLADDR(&sdl_m);
endp = ((caddr_t)&sdl_m) + sdl_m.sdl_len;
if (endp > (p + ETHER_ADDR_LEN))
endp = p + ETHER_ADDR_LEN;
while (p < endp) {
*p++ = *haddr++;
}
sdl_m.sdl_alen = ETHER_ADDR_LEN;
/*
* We need to close and open the socket to prevent routing updates
* building up such that when we send our message we never see our
* reply (and hang)
*/
s = socket(PF_ROUTE, SOCK_RAW, 0);
if (s < 0)
err(1, "socket");
rtm->rtm_flags = 0;
if (rtmsg(RTM_GET, s, rtm, &sin_m, &sdl_m) < 0) {
#if 0
warn("%s", host);
#endif
close(s);
return (1);
}
sin = (struct sockaddr_inarp *)(rtm + 1);
sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
if (sdl->sdl_family == AF_LINK &&
(rtm->rtm_flags & RTF_LLINFO) &&
!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET:
goto overwrite;
}
#if 0
(void)printf("set: can only proxy for %s\n", host);
#endif
close(s);
return (1);
}
overwrite:
if (sdl->sdl_family != AF_LINK) {
#if 0
(void)printf("cannot intuit interface index and type for %s\n",
host);
#endif
close(s);
return (1);
}
sdl_m.sdl_type = sdl->sdl_type;
sdl_m.sdl_index = sdl->sdl_index;
result = rtmsg(RTM_ADD, s, rtm, &sin_m, &sdl_m);
close(s);
return (result);
}
int
rtmsg(int cmd, int s, struct rt_msghdr *rtm, struct sockaddr_inarp *sin_m,
struct sockaddr_dl *sdl_m)
{
static int seq;
int rlen;
char *cp;
int l;
pid_t pid;
struct timeval time;
rtm = &m_rtmsg.m_rtm;
cp = m_rtmsg.m_space;
errno = 0;
pid = getpid();
(void)memset(&m_rtmsg, 0, sizeof(m_rtmsg));
rtm->rtm_version = RTM_VERSION;
switch (cmd) {
default:
errx(1, "internal wrong cmd");
/*NOTREACHED*/
case RTM_ADD:
rtm->rtm_addrs |= RTA_GATEWAY;
(void)gettimeofday(&time, 0);
rtm->rtm_rmx.rmx_expire = time.tv_sec + 20 * 60;
rtm->rtm_inits = RTV_EXPIRE;
rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
sin_m->sin_other = 0;
/* FALLTHROUGH */
case RTM_GET:
rtm->rtm_addrs |= RTA_DST;
}
#define NEXTADDR(w, s) \
if (rtm->rtm_addrs & (w)) { \
(void)memcpy(cp, s, ((struct sockaddr *)s)->sa_len); \
cp += ROUNDUP(((struct sockaddr *)s)->sa_len);}
NEXTADDR(RTA_DST, sin_m);
NEXTADDR(RTA_GATEWAY, sdl_m);
rtm->rtm_msglen = cp - (char *)&m_rtmsg;
l = rtm->rtm_msglen;
rtm->rtm_seq = ++seq;
rtm->rtm_type = cmd;
if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
if (errno != ESRCH && errno != EEXIST) {
warn("writing to routing socket");
return (-1);
}
}
do {
l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
} while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
if (l < 0)
warn("read from routing socket");
return (0);
}