xref: /freebsd/libexec/bootpd/rtmsg.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*
2  * Copyright (c) 1984, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 1994
5  *	Geoffrey M. Rehmet, All rights reserved.
6  *
7  * This code is derived from software which forms part of the 4.4-Lite
8  * Berkeley software distribution, which was in derived from software
9  * contributed to Berkeley by Sun Microsystems, Inc.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the University of
22  *	California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 /*
41  * from arp.c	8.2 (Berkeley) 1/2/94
42  */
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #include <sys/param.h>
48 /*
49  * Verify that we are at least 4.4 BSD
50  */
51 #if defined(BSD)
52 #if BSD >= 199306
53 
54 #include <sys/socket.h>
55 #include <sys/filio.h>
56 #include <sys/time.h>
57 
58 #include <net/if.h>
59 #include <net/if_dl.h>
60 #include <net/if_types.h>
61 #include <net/route.h>
62 
63 #include <netinet/in.h>
64 #include <netinet/if_ether.h>
65 
66 #include <arpa/inet.h>
67 
68 #include <errno.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <string.h>
72 #include <syslog.h>
73 #include <unistd.h>
74 
75 #include "report.h"
76 
77 
78 static int rtmsg(int);
79 
80 static int s = -1; 	/* routing socket */
81 
82 
83 /*
84  * Open the routing socket
85  */
86 static void getsocket () {
87 	if (s < 0) {
88 		s = socket(PF_ROUTE, SOCK_RAW, 0);
89 		if (s < 0) {
90 			report(LOG_ERR, "socket %s", strerror(errno));
91 			exit(1);
92 		}
93 	} else {
94 		/*
95 		 * Drain the socket of any unwanted routing messages.
96 		 */
97 		int n;
98 		char buf[512];
99 
100 		ioctl(s, FIONREAD, &n);
101 		while (n > 0) {
102 			read(s, buf, sizeof buf);
103 			ioctl(s, FIONREAD, &n);
104 		}
105 	}
106 }
107 
108 static struct	sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
109 static struct	sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
110 static struct	sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
111 static int	expire_time, flags, export_only, doing_proxy;
112 static struct	{
113 	struct	rt_msghdr m_rtm;
114 	char	m_space[512];
115 }	m_rtmsg;
116 
117 /*
118  * Set an individual arp entry
119  */
120 int bsd_arp_set(ia, eaddr, len)
121 	struct in_addr *ia;
122 	char *eaddr;
123 	int len;
124 {
125 	register struct sockaddr_inarp *sin = &sin_m;
126 	register struct sockaddr_dl *sdl;
127 	register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
128 	u_char *ea;
129 	struct timeval time;
130 	int op = RTM_ADD;
131 
132 	getsocket();
133 	sdl_m = blank_sdl;
134 	sin_m = blank_sin;
135 	sin->sin_addr = *ia;
136 
137 	ea = (u_char *)LLADDR(&sdl_m);
138 	bcopy(eaddr, ea, len);
139 	sdl_m.sdl_alen = len;
140 	doing_proxy = flags = export_only = expire_time = 0;
141 
142 	/* make arp entry temporary */
143 	gettimeofday(&time, 0);
144 	expire_time = time.tv_sec + 20 * 60;
145 
146 tryagain:
147 	if (rtmsg(RTM_GET) < 0) {
148 		report(LOG_WARNING, "rtmget: %s", strerror(errno));
149 		return (1);
150 	}
151 	sin = (struct sockaddr_inarp *)(rtm + 1);
152 	sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
153 	if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
154 		if (sdl->sdl_family == AF_LINK &&
155 		    !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
156 		case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
157 		case IFT_ISO88024: case IFT_ISO88025:
158 			op = RTM_CHANGE;
159 			goto overwrite;
160 		}
161 		if (doing_proxy == 0) {
162 			report(LOG_WARNING, "set: can only proxy for %s\n",
163 				inet_ntoa(sin->sin_addr));
164 			return (1);
165 		}
166 		if (sin_m.sin_other & SIN_PROXY) {
167 			report(LOG_WARNING,
168 				"set: proxy entry exists for non 802 device\n");
169 			return(1);
170 		}
171 		sin_m.sin_other = SIN_PROXY;
172 		export_only = 1;
173 		goto tryagain;
174 	}
175 overwrite:
176 	if (sdl->sdl_family != AF_LINK) {
177 		report(LOG_WARNING,
178 			"cannot intuit interface index and type for %s\n",
179 			inet_ntoa(sin->sin_addr));
180 		return (1);
181 	}
182 	sdl_m.sdl_type = sdl->sdl_type;
183 	sdl_m.sdl_index = sdl->sdl_index;
184 	return (rtmsg(op));
185 }
186 
187 
188 static int rtmsg(cmd)
189 	int cmd;
190 {
191 	static int seq;
192 	int rlen;
193 	register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
194 	register char *cp = m_rtmsg.m_space;
195 	register int l;
196 
197 	errno = 0;
198 	bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
199 	rtm->rtm_flags = flags;
200 	rtm->rtm_version = RTM_VERSION;
201 
202 	switch (cmd) {
203 	default:
204 		report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
205 		exit(1);
206 	case RTM_ADD:
207 	case RTM_CHANGE:
208 		rtm->rtm_addrs |= RTA_GATEWAY;
209 		rtm->rtm_rmx.rmx_expire = expire_time;
210 		rtm->rtm_inits = RTV_EXPIRE;
211 		rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
212 		sin_m.sin_other = 0;
213 		if (doing_proxy) {
214 			if (export_only)
215 				sin_m.sin_other = SIN_PROXY;
216 			else {
217 				rtm->rtm_addrs |= RTA_NETMASK;
218 				rtm->rtm_flags &= ~RTF_HOST;
219 			}
220 		}
221 		/* FALLTHROUGH */
222 	case RTM_GET:
223 		rtm->rtm_addrs |= RTA_DST;
224 	}
225 #define NEXTADDR(w, s) \
226 	if (rtm->rtm_addrs & (w)) { \
227 		bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
228 
229 	NEXTADDR(RTA_DST, sin_m);
230 	NEXTADDR(RTA_GATEWAY, sdl_m);
231 	NEXTADDR(RTA_NETMASK, so_mask);
232 
233 	rtm->rtm_msglen = cp - (char *)&m_rtmsg;
234 
235 	l = rtm->rtm_msglen;
236 	rtm->rtm_seq = ++seq;
237 	rtm->rtm_type = cmd;
238 	if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
239 		if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
240 			report(LOG_WARNING, "writing to routing socket: %s",
241 				strerror(errno));
242 			return (-1);
243 		}
244 	}
245 	do {
246 		l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
247 	} while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
248 	if (l < 0)
249 		report(LOG_WARNING, "arp: read from routing socket: %s\n",
250 		    strerror(errno));
251 	return (0);
252 }
253 
254 #endif /* BSD */
255 #endif /* BSD >= 199306 */
256