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 */ 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 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 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