1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1984, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 * Copyright (c) 1994
7 *	Geoffrey M. Rehmet, All rights reserved.
8 *
9 * This code is derived from software which forms part of the 4.4-Lite
10 * Berkeley software distribution, which was in derived from software
11 * contributed to Berkeley by Sun Microsystems, Inc.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38/*
39 * from arp.c	8.2 (Berkeley) 1/2/94
40 */
41
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD$");
44
45#include <sys/param.h>
46/*
47 * Verify that we are at least 4.4 BSD
48 */
49#if defined(BSD)
50#if BSD >= 199306
51
52#include <sys/socket.h>
53#include <sys/filio.h>
54#include <sys/time.h>
55
56#include <net/if.h>
57#include <net/if_dl.h>
58#include <net/if_types.h>
59#include <net/route.h>
60
61#include <netinet/in.h>
62#include <netinet/if_ether.h>
63
64#include <arpa/inet.h>
65
66#include <errno.h>
67#include <stdio.h>
68#include <stdlib.h>
69#include <string.h>
70#include <syslog.h>
71#include <unistd.h>
72
73#include "report.h"
74
75
76static int rtmsg(int);
77
78static int s = -1; 	/* routing socket */
79
80
81/*
82 * Open the routing socket
83 */
84static void getsocket () {
85	if (s < 0) {
86		s = socket(PF_ROUTE, SOCK_RAW, 0);
87		if (s < 0) {
88			report(LOG_ERR, "socket %s", strerror(errno));
89			exit(1);
90		}
91	} else {
92		/*
93		 * Drain the socket of any unwanted routing messages.
94		 */
95		int n;
96		char buf[512];
97
98		ioctl(s, FIONREAD, &n);
99		while (n > 0) {
100			read(s, buf, sizeof buf);
101			ioctl(s, FIONREAD, &n);
102		}
103	}
104}
105
106static struct	sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
107static struct	sockaddr_in blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
108static struct	sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
109static int	expire_time, flags, doing_proxy;
110static struct	{
111	struct	rt_msghdr m_rtm;
112	char	m_space[512];
113}	m_rtmsg;
114
115/*
116 * Set an individual arp entry
117 */
118int bsd_arp_set(ia, eaddr, len)
119	struct in_addr *ia;
120	char *eaddr;
121	int len;
122{
123	struct sockaddr_in *sin = &sin_m;
124	struct sockaddr_dl *sdl;
125	struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
126	u_char *ea;
127	struct timespec tp;
128	int op = RTM_ADD;
129
130	getsocket();
131	sdl_m = blank_sdl;
132	sin_m = blank_sin;
133	sin->sin_addr = *ia;
134
135	ea = (u_char *)LLADDR(&sdl_m);
136	bcopy(eaddr, ea, len);
137	sdl_m.sdl_alen = len;
138	doing_proxy = flags = expire_time = 0;
139
140	/* make arp entry temporary */
141	clock_gettime(CLOCK_MONOTONIC, &tp);
142	expire_time = tp.tv_sec + 20 * 60;
143
144tryagain:
145	if (rtmsg(RTM_GET) < 0) {
146		report(LOG_WARNING, "rtmget: %s", strerror(errno));
147		return (1);
148	}
149	sin = (struct sockaddr_in *)(rtm + 1);
150	sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
151	if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
152		if (sdl->sdl_family == AF_LINK &&
153		    !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
154		case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
155		case IFT_ISO88024: case IFT_ISO88025:
156			op = RTM_CHANGE;
157			goto overwrite;
158		}
159		if (doing_proxy == 0) {
160			report(LOG_WARNING, "set: can only proxy for %s\n",
161				inet_ntoa(sin->sin_addr));
162			return (1);
163		}
164		goto tryagain;
165	}
166overwrite:
167	if (sdl->sdl_family != AF_LINK) {
168		report(LOG_WARNING,
169			"cannot intuit interface index and type for %s\n",
170			inet_ntoa(sin->sin_addr));
171		return (1);
172	}
173	sdl_m.sdl_type = sdl->sdl_type;
174	sdl_m.sdl_index = sdl->sdl_index;
175	return (rtmsg(op));
176}
177
178
179static int rtmsg(cmd)
180	int cmd;
181{
182	static int seq;
183	int rlen;
184	struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
185	char *cp = m_rtmsg.m_space;
186	int l;
187
188	errno = 0;
189	bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
190	rtm->rtm_flags = flags;
191	rtm->rtm_version = RTM_VERSION;
192
193	switch (cmd) {
194	default:
195		report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
196		exit(1);
197	case RTM_ADD:
198	case RTM_CHANGE:
199		rtm->rtm_addrs |= RTA_GATEWAY;
200		rtm->rtm_rmx.rmx_expire = expire_time;
201		rtm->rtm_inits = RTV_EXPIRE;
202		rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
203		if (doing_proxy) {
204			rtm->rtm_addrs |= RTA_NETMASK;
205			rtm->rtm_flags &= ~RTF_HOST;
206		}
207		/* FALLTHROUGH */
208	case RTM_GET:
209		rtm->rtm_addrs |= RTA_DST;
210	}
211#define NEXTADDR(w, s) \
212	if (rtm->rtm_addrs & (w)) { \
213		bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
214
215	NEXTADDR(RTA_DST, sin_m);
216	NEXTADDR(RTA_GATEWAY, sdl_m);
217	NEXTADDR(RTA_NETMASK, so_mask);
218
219	rtm->rtm_msglen = cp - (char *)&m_rtmsg;
220
221	l = rtm->rtm_msglen;
222	rtm->rtm_seq = ++seq;
223	rtm->rtm_type = cmd;
224	if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
225		if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
226			report(LOG_WARNING, "writing to routing socket: %s",
227				strerror(errno));
228			return (-1);
229		}
230	}
231	do {
232		l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
233	} while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
234	if (l < 0)
235		report(LOG_WARNING, "arp: read from routing socket: %s\n",
236		    strerror(errno));
237	return (0);
238}
239
240#endif /* BSD */
241#endif /* BSD >= 199306 */
242