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 119 bsd_arp_set(struct in_addr *ia, char *eaddr, int len) 120 { 121 struct sockaddr_in *sin = &sin_m; 122 struct sockaddr_dl *sdl; 123 struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 124 u_char *ea; 125 struct timespec tp; 126 int op = RTM_ADD; 127 128 getsocket(); 129 sdl_m = blank_sdl; 130 sin_m = blank_sin; 131 sin->sin_addr = *ia; 132 133 ea = (u_char *)LLADDR(&sdl_m); 134 bcopy(eaddr, ea, len); 135 sdl_m.sdl_alen = len; 136 doing_proxy = flags = expire_time = 0; 137 138 /* make arp entry temporary */ 139 clock_gettime(CLOCK_MONOTONIC, &tp); 140 expire_time = tp.tv_sec + 20 * 60; 141 142 tryagain: 143 if (rtmsg(RTM_GET) < 0) { 144 report(LOG_WARNING, "rtmget: %s", strerror(errno)); 145 return (1); 146 } 147 sin = (struct sockaddr_in *)(rtm + 1); 148 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 149 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 150 if (sdl->sdl_family == AF_LINK && 151 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 152 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 153 case IFT_ISO88024: case IFT_ISO88025: 154 op = RTM_CHANGE; 155 goto overwrite; 156 } 157 if (doing_proxy == 0) { 158 report(LOG_WARNING, "set: can only proxy for %s\n", 159 inet_ntoa(sin->sin_addr)); 160 return (1); 161 } 162 goto tryagain; 163 } 164 overwrite: 165 if (sdl->sdl_family != AF_LINK) { 166 report(LOG_WARNING, 167 "cannot intuit interface index and type for %s\n", 168 inet_ntoa(sin->sin_addr)); 169 return (1); 170 } 171 sdl_m.sdl_type = sdl->sdl_type; 172 sdl_m.sdl_index = sdl->sdl_index; 173 return (rtmsg(op)); 174 } 175 176 177 static int 178 rtmsg(int cmd) 179 { 180 static int seq; 181 int rlen; 182 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 183 char *cp = m_rtmsg.m_space; 184 int l; 185 186 errno = 0; 187 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 188 rtm->rtm_flags = flags; 189 rtm->rtm_version = RTM_VERSION; 190 191 switch (cmd) { 192 default: 193 report(LOG_ERR, "set_arp: internal wrong cmd - exiting"); 194 exit(1); 195 case RTM_ADD: 196 case RTM_CHANGE: 197 rtm->rtm_addrs |= RTA_GATEWAY; 198 rtm->rtm_rmx.rmx_expire = expire_time; 199 rtm->rtm_inits = RTV_EXPIRE; 200 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 201 if (doing_proxy) { 202 rtm->rtm_addrs |= RTA_NETMASK; 203 rtm->rtm_flags &= ~RTF_HOST; 204 } 205 /* FALLTHROUGH */ 206 case RTM_GET: 207 rtm->rtm_addrs |= RTA_DST; 208 } 209 #define NEXTADDR(w, s) \ 210 if (rtm->rtm_addrs & (w)) { \ 211 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 212 213 NEXTADDR(RTA_DST, sin_m); 214 NEXTADDR(RTA_GATEWAY, sdl_m); 215 NEXTADDR(RTA_NETMASK, so_mask); 216 217 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 218 219 l = rtm->rtm_msglen; 220 rtm->rtm_seq = ++seq; 221 rtm->rtm_type = cmd; 222 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 223 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){ 224 report(LOG_WARNING, "writing to routing socket: %s", 225 strerror(errno)); 226 return (-1); 227 } 228 } 229 do { 230 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 231 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid())); 232 if (l < 0) 233 report(LOG_WARNING, "arp: read from routing socket: %s\n", 234 strerror(errno)); 235 return (0); 236 } 237 238 #endif /* BSD */ 239 #endif /* BSD >= 199306 */ 240