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 76 static int rtmsg(int); 77 78 static int s = -1; /* routing socket */ 79 80 81 /* 82 * Open the routing socket 83 */ 84 static 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 } 105 106 static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 107 static struct sockaddr_in blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 108 static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 109 static int expire_time, flags, doing_proxy; 110 static struct { 111 struct rt_msghdr m_rtm; 112 char m_space[512]; 113 } m_rtmsg; 114 115 /* 116 * Set an individual arp entry 117 */ 118 int 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; 143 144 tryagain: 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 } 166 overwrite: 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 } 177 178 179 static 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