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/param.h> 43 /* 44 * Verify that we are at least 4.4 BSD 45 */ 46 #if defined(BSD) 47 #if BSD >= 199306 48 49 #include <sys/socket.h> 50 #include <sys/filio.h> 51 #include <sys/time.h> 52 53 #include <net/if.h> 54 #include <net/if_dl.h> 55 #include <net/if_types.h> 56 #include <net/route.h> 57 58 #include <netinet/in.h> 59 #include <netinet/if_ether.h> 60 61 #include <arpa/inet.h> 62 63 #include <errno.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <unistd.h> 69 70 #include "report.h" 71 72 73 static int rtmsg(int); 74 75 static int s = -1; /* routing socket */ 76 77 78 /* 79 * Open the routing socket 80 */ 81 static void getsocket () { 82 if (s < 0) { 83 s = socket(PF_ROUTE, SOCK_RAW, 0); 84 if (s < 0) { 85 report(LOG_ERR, "socket %s", strerror(errno)); 86 exit(1); 87 } 88 } else { 89 /* 90 * Drain the socket of any unwanted routing messages. 91 */ 92 int n; 93 char buf[512]; 94 95 ioctl(s, FIONREAD, &n); 96 while (n > 0) { 97 read(s, buf, sizeof buf); 98 ioctl(s, FIONREAD, &n); 99 } 100 } 101 } 102 103 static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 104 static struct sockaddr_in blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 105 static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 106 static int expire_time, flags, doing_proxy; 107 static struct { 108 struct rt_msghdr m_rtm; 109 char m_space[512]; 110 } m_rtmsg; 111 112 /* 113 * Set an individual arp entry 114 */ 115 int 116 bsd_arp_set(struct in_addr *ia, char *eaddr, int len) 117 { 118 struct sockaddr_in *sin = &sin_m; 119 struct sockaddr_dl *sdl; 120 struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 121 u_char *ea; 122 struct timespec tp; 123 int op = RTM_ADD; 124 125 getsocket(); 126 sdl_m = blank_sdl; 127 sin_m = blank_sin; 128 sin->sin_addr = *ia; 129 130 ea = (u_char *)LLADDR(&sdl_m); 131 bcopy(eaddr, ea, len); 132 sdl_m.sdl_alen = len; 133 doing_proxy = flags = expire_time = 0; 134 135 /* make arp entry temporary */ 136 clock_gettime(CLOCK_MONOTONIC, &tp); 137 expire_time = tp.tv_sec + 20 * 60; 138 139 tryagain: 140 if (rtmsg(RTM_GET) < 0) { 141 report(LOG_WARNING, "rtmget: %s", strerror(errno)); 142 return (1); 143 } 144 sin = (struct sockaddr_in *)(rtm + 1); 145 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 146 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 147 if (sdl->sdl_family == AF_LINK && 148 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 149 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 150 case IFT_ISO88024: case IFT_ISO88025: 151 op = RTM_CHANGE; 152 goto overwrite; 153 } 154 if (doing_proxy == 0) { 155 report(LOG_WARNING, "set: can only proxy for %s\n", 156 inet_ntoa(sin->sin_addr)); 157 return (1); 158 } 159 goto tryagain; 160 } 161 overwrite: 162 if (sdl->sdl_family != AF_LINK) { 163 report(LOG_WARNING, 164 "cannot intuit interface index and type for %s\n", 165 inet_ntoa(sin->sin_addr)); 166 return (1); 167 } 168 sdl_m.sdl_type = sdl->sdl_type; 169 sdl_m.sdl_index = sdl->sdl_index; 170 return (rtmsg(op)); 171 } 172 173 174 static int 175 rtmsg(int cmd) 176 { 177 static int seq; 178 int rlen; 179 struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 180 char *cp = m_rtmsg.m_space; 181 int l; 182 183 errno = 0; 184 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 185 rtm->rtm_flags = flags; 186 rtm->rtm_version = RTM_VERSION; 187 188 switch (cmd) { 189 default: 190 report(LOG_ERR, "set_arp: internal wrong cmd - exiting"); 191 exit(1); 192 case RTM_ADD: 193 case RTM_CHANGE: 194 rtm->rtm_addrs |= RTA_GATEWAY; 195 rtm->rtm_rmx.rmx_expire = expire_time; 196 rtm->rtm_inits = RTV_EXPIRE; 197 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 198 if (doing_proxy) { 199 rtm->rtm_addrs |= RTA_NETMASK; 200 rtm->rtm_flags &= ~RTF_HOST; 201 } 202 /* FALLTHROUGH */ 203 case RTM_GET: 204 rtm->rtm_addrs |= RTA_DST; 205 } 206 #define NEXTADDR(w, s) \ 207 if (rtm->rtm_addrs & (w)) { \ 208 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 209 210 NEXTADDR(RTA_DST, sin_m); 211 NEXTADDR(RTA_GATEWAY, sdl_m); 212 NEXTADDR(RTA_NETMASK, so_mask); 213 214 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 215 216 l = rtm->rtm_msglen; 217 rtm->rtm_seq = ++seq; 218 rtm->rtm_type = cmd; 219 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 220 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){ 221 report(LOG_WARNING, "writing to routing socket: %s", 222 strerror(errno)); 223 return (-1); 224 } 225 } 226 do { 227 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 228 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid())); 229 if (l < 0) 230 report(LOG_WARNING, "arp: read from routing socket: %s\n", 231 strerror(errno)); 232 return (0); 233 } 234 235 #endif /* BSD */ 236 #endif /* BSD >= 199306 */ 237