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 #include <sys/param.h>
44 /*
45 * Verify that we are at least 4.4 BSD
46 */
47 #if defined(BSD)
48 #if BSD >= 199306
49
50 #include <sys/socket.h>
51 #include <sys/filio.h>
52 #include <sys/time.h>
53
54 #include <net/if.h>
55 #include <net/if_dl.h>
56 #include <net/if_types.h>
57 #include <net/route.h>
58
59 #include <netinet/in.h>
60 #include <netinet/if_ether.h>
61
62 #include <arpa/inet.h>
63
64 #include <errno.h>
65 #include <stdio.h>
66 #include <stdlib.h>
67 #include <string.h>
68 #include <syslog.h>
69 #include <unistd.h>
70
71 #include "report.h"
72
73
74 static int rtmsg(int);
75
76 static int s = -1; /* routing socket */
77
78
79 /*
80 * Open the routing socket
81 */
getsocket()82 static void getsocket () {
83 if (s < 0) {
84 s = socket(PF_ROUTE, SOCK_RAW, 0);
85 if (s < 0) {
86 report(LOG_ERR, "socket %s", strerror(errno));
87 exit(1);
88 }
89 } else {
90 /*
91 * Drain the socket of any unwanted routing messages.
92 */
93 int n;
94 char buf[512];
95
96 ioctl(s, FIONREAD, &n);
97 while (n > 0) {
98 read(s, buf, sizeof buf);
99 ioctl(s, FIONREAD, &n);
100 }
101 }
102 }
103
104 static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
105 static struct sockaddr_in blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
106 static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
107 static int expire_time, flags, doing_proxy;
108 static struct {
109 struct rt_msghdr m_rtm;
110 char m_space[512];
111 } m_rtmsg;
112
113 /*
114 * Set an individual arp entry
115 */
116 int
bsd_arp_set(struct in_addr * ia,char * eaddr,int len)117 bsd_arp_set(struct in_addr *ia, char *eaddr, int len)
118 {
119 struct sockaddr_in *sin = &sin_m;
120 struct sockaddr_dl *sdl;
121 struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
122 u_char *ea;
123 struct timespec tp;
124 int op = RTM_ADD;
125
126 getsocket();
127 sdl_m = blank_sdl;
128 sin_m = blank_sin;
129 sin->sin_addr = *ia;
130
131 ea = (u_char *)LLADDR(&sdl_m);
132 bcopy(eaddr, ea, len);
133 sdl_m.sdl_alen = len;
134 doing_proxy = flags = expire_time = 0;
135
136 /* make arp entry temporary */
137 clock_gettime(CLOCK_MONOTONIC, &tp);
138 expire_time = tp.tv_sec + 20 * 60;
139
140 tryagain:
141 if (rtmsg(RTM_GET) < 0) {
142 report(LOG_WARNING, "rtmget: %s", strerror(errno));
143 return (1);
144 }
145 sin = (struct sockaddr_in *)(rtm + 1);
146 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
147 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
148 if (sdl->sdl_family == AF_LINK &&
149 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
150 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
151 case IFT_ISO88024: case IFT_ISO88025:
152 op = RTM_CHANGE;
153 goto overwrite;
154 }
155 if (doing_proxy == 0) {
156 report(LOG_WARNING, "set: can only proxy for %s\n",
157 inet_ntoa(sin->sin_addr));
158 return (1);
159 }
160 goto tryagain;
161 }
162 overwrite:
163 if (sdl->sdl_family != AF_LINK) {
164 report(LOG_WARNING,
165 "cannot intuit interface index and type for %s\n",
166 inet_ntoa(sin->sin_addr));
167 return (1);
168 }
169 sdl_m.sdl_type = sdl->sdl_type;
170 sdl_m.sdl_index = sdl->sdl_index;
171 return (rtmsg(op));
172 }
173
174
175 static int
rtmsg(int cmd)176 rtmsg(int cmd)
177 {
178 static int seq;
179 int rlen;
180 struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
181 char *cp = m_rtmsg.m_space;
182 int l;
183
184 errno = 0;
185 bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
186 rtm->rtm_flags = flags;
187 rtm->rtm_version = RTM_VERSION;
188
189 switch (cmd) {
190 default:
191 report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
192 exit(1);
193 case RTM_ADD:
194 case RTM_CHANGE:
195 rtm->rtm_addrs |= RTA_GATEWAY;
196 rtm->rtm_rmx.rmx_expire = expire_time;
197 rtm->rtm_inits = RTV_EXPIRE;
198 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
199 if (doing_proxy) {
200 rtm->rtm_addrs |= RTA_NETMASK;
201 rtm->rtm_flags &= ~RTF_HOST;
202 }
203 /* FALLTHROUGH */
204 case RTM_GET:
205 rtm->rtm_addrs |= RTA_DST;
206 }
207 #define NEXTADDR(w, s) \
208 if (rtm->rtm_addrs & (w)) { \
209 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
210
211 NEXTADDR(RTA_DST, sin_m);
212 NEXTADDR(RTA_GATEWAY, sdl_m);
213 NEXTADDR(RTA_NETMASK, so_mask);
214
215 rtm->rtm_msglen = cp - (char *)&m_rtmsg;
216
217 l = rtm->rtm_msglen;
218 rtm->rtm_seq = ++seq;
219 rtm->rtm_type = cmd;
220 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
221 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
222 report(LOG_WARNING, "writing to routing socket: %s",
223 strerror(errno));
224 return (-1);
225 }
226 }
227 do {
228 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
229 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
230 if (l < 0)
231 report(LOG_WARNING, "arp: read from routing socket: %s\n",
232 strerror(errno));
233 return (0);
234 }
235
236 #endif /* BSD */
237 #endif /* BSD >= 199306 */
238