1 /* $NetBSD: mkarp.c,v 1.5 2003/04/08 04:04:01 petrov Exp $ */ 2 3 /* 4 * Copyright (c) 1984, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Sun Microsystems, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 __COPYRIGHT("@(#) Copyright (c) 1984, 1993\n\ 42 The Regents of the University of California. All rights reserved.\n"); 43 #endif /* not lint */ 44 45 #ifndef lint 46 #if 0 47 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 48 #else 49 __RCSID("$NetBSD: mkarp.c,v 1.5 2003/04/08 04:04:01 petrov Exp $"); 50 #endif 51 #endif /* not lint */ 52 53 /* 54 * mkarp - set an arp table entry 55 */ 56 57 #include <sys/param.h> 58 #include <sys/file.h> 59 #include <sys/socket.h> 60 #include <sys/sysctl.h> 61 62 #include <net/if.h> 63 #include <net/if_dl.h> 64 #include <net/if_ether.h> 65 #include <net/if_types.h> 66 #include <net/route.h> 67 #include <netinet/in.h> 68 #include <netinet/if_inarp.h> 69 #include <arpa/inet.h> 70 71 #include <err.h> 72 #include <errno.h> 73 #include <netdb.h> 74 #include <nlist.h> 75 #include <paths.h> 76 #include <stdio.h> 77 #include <stdlib.h> 78 #include <string.h> 79 #include <unistd.h> 80 81 #include "mkarp.h" 82 83 /* Roundup the same way rt_xaddrs does */ 84 #define ROUNDUP(a) \ 85 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 86 87 int rtmsg(int, int, struct rt_msghdr *, struct sockaddr_inarp *, 88 struct sockaddr_dl *); 89 struct { 90 struct rt_msghdr m_rtm; 91 char m_space[512]; 92 } m_rtmsg; 93 94 /* 95 * Set an individual arp entry 96 */ 97 int 98 mkarp(u_char *haddr, u_int32_t ipaddr) 99 { 100 static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }; 101 static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }; 102 103 struct sockaddr_inarp *sin; 104 struct sockaddr_dl *sdl; 105 struct rt_msghdr *rtm; 106 u_int8_t *p, *endp; 107 int result; 108 int s; 109 110 struct sockaddr_inarp sin_m; 111 struct sockaddr_dl sdl_m; 112 113 sin = &sin_m; 114 rtm = &(m_rtmsg.m_rtm); 115 116 sdl_m = blank_sdl; /* struct copy */ 117 sin_m = blank_sin; /* struct copy */ 118 119 sin->sin_addr.s_addr = ipaddr; 120 121 p = LLADDR(&sdl_m); 122 endp = ((caddr_t)&sdl_m) + sdl_m.sdl_len; 123 if (endp > (p + ETHER_ADDR_LEN)) 124 endp = p + ETHER_ADDR_LEN; 125 126 while (p < endp) { 127 *p++ = *haddr++; 128 } 129 sdl_m.sdl_alen = ETHER_ADDR_LEN; 130 131 /* 132 * We need to close and open the socket to prevent routing updates 133 * building up such that when we send our message we never see our 134 * reply (and hang) 135 */ 136 s = socket(PF_ROUTE, SOCK_RAW, 0); 137 if (s < 0) 138 err(1, "socket"); 139 140 rtm->rtm_flags = 0; 141 142 if (rtmsg(RTM_GET, s, rtm, &sin_m, &sdl_m) < 0) { 143 #if 0 144 warn("%s", host); 145 #endif 146 close(s); 147 return (1); 148 } 149 sin = (struct sockaddr_inarp *)(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_LLINFO) && 154 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 155 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 156 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 157 goto overwrite; 158 } 159 #if 0 160 (void)printf("set: can only proxy for %s\n", host); 161 #endif 162 close(s); 163 return (1); 164 } 165 overwrite: 166 if (sdl->sdl_family != AF_LINK) { 167 #if 0 168 (void)printf("cannot intuit interface index and type for %s\n", 169 host); 170 #endif 171 close(s); 172 return (1); 173 } 174 sdl_m.sdl_type = sdl->sdl_type; 175 sdl_m.sdl_index = sdl->sdl_index; 176 result = rtmsg(RTM_ADD, s, rtm, &sin_m, &sdl_m); 177 close(s); 178 return (result); 179 } 180 181 int 182 rtmsg(int cmd, int s, struct rt_msghdr *rtm, struct sockaddr_inarp *sin_m, 183 struct sockaddr_dl *sdl_m) 184 { 185 static int seq; 186 int rlen; 187 char *cp; 188 int l; 189 pid_t pid; 190 struct timeval time; 191 192 rtm = &m_rtmsg.m_rtm; 193 cp = m_rtmsg.m_space; 194 errno = 0; 195 196 pid = getpid(); 197 198 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 199 rtm->rtm_version = RTM_VERSION; 200 201 switch (cmd) { 202 default: 203 errx(1, "internal wrong cmd"); 204 /*NOTREACHED*/ 205 case RTM_ADD: 206 rtm->rtm_addrs |= RTA_GATEWAY; 207 (void)gettimeofday(&time, 0); 208 rtm->rtm_rmx.rmx_expire = time.tv_sec + 20 * 60; 209 rtm->rtm_inits = RTV_EXPIRE; 210 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 211 sin_m->sin_other = 0; 212 213 /* FALLTHROUGH */ 214 case RTM_GET: 215 rtm->rtm_addrs |= RTA_DST; 216 } 217 #define NEXTADDR(w, s) \ 218 if (rtm->rtm_addrs & (w)) { \ 219 (void)memcpy(cp, s, ((struct sockaddr *)s)->sa_len); \ 220 cp += ROUNDUP(((struct sockaddr *)s)->sa_len);} 221 222 NEXTADDR(RTA_DST, sin_m); 223 NEXTADDR(RTA_GATEWAY, sdl_m); 224 225 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 226 227 l = rtm->rtm_msglen; 228 rtm->rtm_seq = ++seq; 229 rtm->rtm_type = cmd; 230 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 231 if (errno != ESRCH && errno != EEXIST) { 232 warn("writing to routing socket"); 233 return (-1); 234 } 235 } 236 do { 237 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 238 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 239 if (l < 0) 240 warn("read from routing socket"); 241 return (0); 242 } 243