241 lines
6.2 KiB
C
241 lines
6.2 KiB
C
/* $NetBSD: mkarp.c,v 1.9 2011/08/30 20:25:18 joerg Exp $ */
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/*
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* Copyright (c) 1984, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Sun Microsystems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__COPYRIGHT("@(#) Copyright (c) 1984, 1993\
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The Regents of the University of California. All rights reserved.");
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#endif /* not lint */
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95";
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#else
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__RCSID("$NetBSD: mkarp.c,v 1.9 2011/08/30 20:25:18 joerg Exp $");
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#endif
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#endif /* not lint */
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/*
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* mkarp - set an arp table entry
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*/
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/if_ether.h>
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#include <net/if_types.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/if_inarp.h>
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#include <arpa/inet.h>
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#include <err.h>
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#include <errno.h>
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#include <netdb.h>
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#include <nlist.h>
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#include <paths.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "mkarp.h"
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/* Roundup the same way rt_xaddrs does */
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#define ROUNDUP(a) \
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((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
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int rtmsg(int, int, struct rt_msghdr *, struct sockaddr_inarp *,
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struct sockaddr_dl *);
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static struct {
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struct rt_msghdr m_rtm;
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char m_space[512];
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} m_rtmsg;
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/*
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* Set an individual arp entry
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*/
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int
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mkarp(u_char *haddr, u_int32_t ipaddr)
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{
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static struct sockaddr_inarp blank_sin = {
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sizeof(blank_sin), AF_INET, 0, { 0 }, { 0 }, 0, 0 };
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static struct sockaddr_dl blank_sdl = {
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sizeof(blank_sdl), AF_LINK, 0, 0, 0, 0, 0, { 0 } };
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struct sockaddr_inarp *sin;
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struct sockaddr_dl *sdl;
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struct rt_msghdr *rtm;
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u_int8_t *p, *endp;
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int result;
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int s;
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struct sockaddr_inarp sin_m;
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struct sockaddr_dl sdl_m;
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sin = &sin_m;
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rtm = &(m_rtmsg.m_rtm);
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sdl_m = blank_sdl; /* struct copy */
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sin_m = blank_sin; /* struct copy */
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sin->sin_addr.s_addr = ipaddr;
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p = LLADDR(&sdl_m);
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endp = ((caddr_t)&sdl_m) + sdl_m.sdl_len;
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if (endp > (p + ETHER_ADDR_LEN))
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endp = p + ETHER_ADDR_LEN;
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while (p < endp) {
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*p++ = *haddr++;
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}
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sdl_m.sdl_alen = ETHER_ADDR_LEN;
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/*
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* We need to close and open the socket to prevent routing updates
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* building up such that when we send our message we never see our
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* reply (and hang)
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*/
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s = socket(PF_ROUTE, SOCK_RAW, 0);
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if (s < 0)
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err(1, "socket");
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rtm->rtm_flags = 0;
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if (rtmsg(RTM_GET, s, rtm, &sin_m, &sdl_m) < 0) {
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#if 0
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warn("%s", host);
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#endif
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close(s);
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return (1);
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}
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sin = (struct sockaddr_inarp *)(rtm + 1);
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sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
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if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
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if (sdl->sdl_family == AF_LINK &&
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(rtm->rtm_flags & RTF_LLINFO) &&
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!(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
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case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
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case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET:
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goto overwrite;
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}
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#if 0
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(void)printf("set: can only proxy for %s\n", host);
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#endif
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close(s);
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return (1);
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}
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overwrite:
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if (sdl->sdl_family != AF_LINK) {
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#if 0
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(void)printf("cannot intuit interface index and type for %s\n",
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host);
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#endif
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close(s);
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return (1);
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}
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sdl_m.sdl_type = sdl->sdl_type;
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sdl_m.sdl_index = sdl->sdl_index;
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result = rtmsg(RTM_ADD, s, rtm, &sin_m, &sdl_m);
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close(s);
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return (result);
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}
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int
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rtmsg(int cmd, int s, struct rt_msghdr *rtm, struct sockaddr_inarp *sin_m,
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struct sockaddr_dl *sdl_m)
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{
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static int seq;
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int rlen;
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char *cp;
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int l;
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pid_t pid;
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struct timeval tv;
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rtm = &m_rtmsg.m_rtm;
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cp = m_rtmsg.m_space;
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errno = 0;
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pid = getpid();
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(void)memset(&m_rtmsg, 0, sizeof(m_rtmsg));
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rtm->rtm_version = RTM_VERSION;
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switch (cmd) {
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default:
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errx(1, "internal wrong cmd");
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/*NOTREACHED*/
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case RTM_ADD:
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rtm->rtm_addrs |= RTA_GATEWAY;
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(void)gettimeofday(&tv, 0);
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rtm->rtm_rmx.rmx_expire = tv.tv_sec + 20 * 60;
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rtm->rtm_inits = RTV_EXPIRE;
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rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
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sin_m->sin_other = 0;
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/* FALLTHROUGH */
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case RTM_GET:
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rtm->rtm_addrs |= RTA_DST;
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}
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#define NEXTADDR(w, s) \
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if (rtm->rtm_addrs & (w)) { \
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(void)memcpy(cp, s, ((struct sockaddr *)s)->sa_len); \
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cp += ROUNDUP(((struct sockaddr *)s)->sa_len);}
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NEXTADDR(RTA_DST, sin_m);
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NEXTADDR(RTA_GATEWAY, sdl_m);
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rtm->rtm_msglen = cp - (char *)&m_rtmsg;
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l = rtm->rtm_msglen;
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rtm->rtm_seq = ++seq;
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rtm->rtm_type = cmd;
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if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
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if (errno != ESRCH && errno != EEXIST) {
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warn("writing to routing socket");
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return (-1);
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}
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}
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do {
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l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
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} while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid));
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if (l < 0)
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warn("read from routing socket");
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return (0);
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}
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