freebsd-dev/libexec/bootpd/rtmsg.c
Doug Rabson 7cb18415b8 Discard any messages which are buffered on the routing socket before using
it otherwise the response to one of our routing messages could be lost due
to buffer overflow.
1995-01-30 11:11:43 +00:00

253 lines
6.7 KiB
C

/*
* Copyright (c) 1984, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1994
* Geoffrey M. Rehmet, All rights reserved.
*
* This code is derived from software which forms part of the 4.4-Lite
* Berkeley software distribution, which was in 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
/*
* from arp.c 8.2 (Berkeley) 1/2/94
* $Id: rtmsg.c,v 1.2 1995/01/16 18:57:45 dfr Exp $
*/
#include <sys/param.h>
/*
* Verify that we are at least 4.4 BSD
*/
#if defined(BSD)
#if BSD >= 199306
#include <sys/socket.h>
#include <sys/filio.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "report.h"
static int rtmsg __P((int));
static int s = -1; /* routing socket */
/*
* Open the routing socket
*/
static void getsocket () {
if (s < 0) {
s = socket(PF_ROUTE, SOCK_RAW, 0);
if (s < 0) {
report(LOG_ERR, "socket %s", strerror(errno));
exit(1);
}
} else {
/*
* Drain the socket of any unwanted routing messages.
*/
int n;
char buf[512];
ioctl(s, FIONREAD, &n);
while (n > 0) {
read(s, buf, sizeof buf);
ioctl(s, FIONREAD, &n);
}
}
}
static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
static int expire_time, flags, export_only, doing_proxy;
static struct {
struct rt_msghdr m_rtm;
char m_space[512];
} m_rtmsg;
/*
* Set an individual arp entry
*/
int bsd_arp_set(ia, eaddr, len)
struct in_addr *ia;
char *eaddr;
int len;
{
register struct sockaddr_inarp *sin = &sin_m;
register struct sockaddr_dl *sdl;
register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
u_char *ea;
struct timeval time;
int op = RTM_ADD;
getsocket();
sdl_m = blank_sdl;
sin_m = blank_sin;
sin->sin_addr = *ia;
ea = (u_char *)LLADDR(&sdl_m);
bcopy(eaddr, ea, len);
sdl_m.sdl_alen = len;
doing_proxy = flags = export_only = expire_time = 0;
/* make arp entry temporary */
gettimeofday(&time, 0);
expire_time = time.tv_sec + 20 * 60;
tryagain:
if (rtmsg(RTM_GET) < 0) {
report(LOG_WARNING, "rtmget: %s", strerror(errno));
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:
op = RTM_CHANGE;
goto overwrite;
}
if (doing_proxy == 0) {
report(LOG_WARNING, "set: can only proxy for %s\n",
inet_ntoa(sin->sin_addr));
return (1);
}
if (sin_m.sin_other & SIN_PROXY) {
report(LOG_WARNING,
"set: proxy entry exists for non 802 device\n");
return(1);
}
sin_m.sin_other = SIN_PROXY;
export_only = 1;
goto tryagain;
}
overwrite:
if (sdl->sdl_family != AF_LINK) {
report(LOG_WARNING,
"cannot intuit interface index and type for %s\n",
inet_ntoa(sin->sin_addr));
return (1);
}
sdl_m.sdl_type = sdl->sdl_type;
sdl_m.sdl_index = sdl->sdl_index;
return (rtmsg(op));
}
static int rtmsg(cmd)
int cmd;
{
static int seq;
int rlen;
register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
register char *cp = m_rtmsg.m_space;
register int l;
errno = 0;
bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
rtm->rtm_flags = flags;
rtm->rtm_version = RTM_VERSION;
switch (cmd) {
default:
report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
exit(1);
case RTM_ADD:
case RTM_CHANGE:
rtm->rtm_addrs |= RTA_GATEWAY;
rtm->rtm_rmx.rmx_expire = expire_time;
rtm->rtm_inits = RTV_EXPIRE;
rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
sin_m.sin_other = 0;
if (doing_proxy) {
if (export_only)
sin_m.sin_other = SIN_PROXY;
else {
rtm->rtm_addrs |= RTA_NETMASK;
rtm->rtm_flags &= ~RTF_HOST;
}
}
/* FALLTHROUGH */
case RTM_GET:
rtm->rtm_addrs |= RTA_DST;
}
#define NEXTADDR(w, s) \
if (rtm->rtm_addrs & (w)) { \
bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
NEXTADDR(RTA_DST, sin_m);
NEXTADDR(RTA_GATEWAY, sdl_m);
NEXTADDR(RTA_NETMASK, so_mask);
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 && cmd == RTM_ADD)){
report(LOG_WARNING, "writing to routing socket: %s",
strerror(errno));
return (-1);
}
}
do {
l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
} while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
if (l < 0)
report(LOG_WARNING, "arp: read from routing socket: %s\n",
strerror(errno));
return (0);
}
#endif /* BSD */
#endif /* BSD >= 199306 */