1 /* $NetBSD: mkarp.c,v 1.6 2003/08/07 11:25:40 agc 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #ifndef lint 37 __COPYRIGHT("@(#) Copyright (c) 1984, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"); 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)arp.c 8.3 (Berkeley) 4/28/95"; 44 #else 45 __RCSID("$NetBSD: mkarp.c,v 1.6 2003/08/07 11:25:40 agc Exp $"); 46 #endif 47 #endif /* not lint */ 48 49 /* 50 * mkarp - set an arp table entry 51 */ 52 53 #include <sys/param.h> 54 #include <sys/file.h> 55 #include <sys/socket.h> 56 #include <sys/sysctl.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/if_ether.h> 61 #include <net/if_types.h> 62 #include <net/route.h> 63 #include <netinet/in.h> 64 #include <netinet/if_inarp.h> 65 #include <arpa/inet.h> 66 67 #include <err.h> 68 #include <errno.h> 69 #include <netdb.h> 70 #include <nlist.h> 71 #include <paths.h> 72 #include <stdio.h> 73 #include <stdlib.h> 74 #include <string.h> 75 #include <unistd.h> 76 77 #include "mkarp.h" 78 79 /* Roundup the same way rt_xaddrs does */ 80 #define ROUNDUP(a) \ 81 ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long)) 82 83 int rtmsg(int, int, struct rt_msghdr *, struct sockaddr_inarp *, 84 struct sockaddr_dl *); 85 struct { 86 struct rt_msghdr m_rtm; 87 char m_space[512]; 88 } m_rtmsg; 89 90 /* 91 * Set an individual arp entry 92 */ 93 int 94 mkarp(u_char *haddr, u_int32_t ipaddr) 95 { 96 static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }; 97 static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }; 98 99 struct sockaddr_inarp *sin; 100 struct sockaddr_dl *sdl; 101 struct rt_msghdr *rtm; 102 u_int8_t *p, *endp; 103 int result; 104 int s; 105 106 struct sockaddr_inarp sin_m; 107 struct sockaddr_dl sdl_m; 108 109 sin = &sin_m; 110 rtm = &(m_rtmsg.m_rtm); 111 112 sdl_m = blank_sdl; /* struct copy */ 113 sin_m = blank_sin; /* struct copy */ 114 115 sin->sin_addr.s_addr = ipaddr; 116 117 p = LLADDR(&sdl_m); 118 endp = ((caddr_t)&sdl_m) + sdl_m.sdl_len; 119 if (endp > (p + ETHER_ADDR_LEN)) 120 endp = p + ETHER_ADDR_LEN; 121 122 while (p < endp) { 123 *p++ = *haddr++; 124 } 125 sdl_m.sdl_alen = ETHER_ADDR_LEN; 126 127 /* 128 * We need to close and open the socket to prevent routing updates 129 * building up such that when we send our message we never see our 130 * reply (and hang) 131 */ 132 s = socket(PF_ROUTE, SOCK_RAW, 0); 133 if (s < 0) 134 err(1, "socket"); 135 136 rtm->rtm_flags = 0; 137 138 if (rtmsg(RTM_GET, s, rtm, &sin_m, &sdl_m) < 0) { 139 #if 0 140 warn("%s", host); 141 #endif 142 close(s); 143 return (1); 144 } 145 sin = (struct sockaddr_inarp *)(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_LLINFO) && 150 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 151 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 152 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 153 goto overwrite; 154 } 155 #if 0 156 (void)printf("set: can only proxy for %s\n", host); 157 #endif 158 close(s); 159 return (1); 160 } 161 overwrite: 162 if (sdl->sdl_family != AF_LINK) { 163 #if 0 164 (void)printf("cannot intuit interface index and type for %s\n", 165 host); 166 #endif 167 close(s); 168 return (1); 169 } 170 sdl_m.sdl_type = sdl->sdl_type; 171 sdl_m.sdl_index = sdl->sdl_index; 172 result = rtmsg(RTM_ADD, s, rtm, &sin_m, &sdl_m); 173 close(s); 174 return (result); 175 } 176 177 int 178 rtmsg(int cmd, int s, struct rt_msghdr *rtm, struct sockaddr_inarp *sin_m, 179 struct sockaddr_dl *sdl_m) 180 { 181 static int seq; 182 int rlen; 183 char *cp; 184 int l; 185 pid_t pid; 186 struct timeval time; 187 188 rtm = &m_rtmsg.m_rtm; 189 cp = m_rtmsg.m_space; 190 errno = 0; 191 192 pid = getpid(); 193 194 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 195 rtm->rtm_version = RTM_VERSION; 196 197 switch (cmd) { 198 default: 199 errx(1, "internal wrong cmd"); 200 /*NOTREACHED*/ 201 case RTM_ADD: 202 rtm->rtm_addrs |= RTA_GATEWAY; 203 (void)gettimeofday(&time, 0); 204 rtm->rtm_rmx.rmx_expire = time.tv_sec + 20 * 60; 205 rtm->rtm_inits = RTV_EXPIRE; 206 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 207 sin_m->sin_other = 0; 208 209 /* FALLTHROUGH */ 210 case RTM_GET: 211 rtm->rtm_addrs |= RTA_DST; 212 } 213 #define NEXTADDR(w, s) \ 214 if (rtm->rtm_addrs & (w)) { \ 215 (void)memcpy(cp, s, ((struct sockaddr *)s)->sa_len); \ 216 cp += ROUNDUP(((struct sockaddr *)s)->sa_len);} 217 218 NEXTADDR(RTA_DST, sin_m); 219 NEXTADDR(RTA_GATEWAY, sdl_m); 220 221 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 222 223 l = rtm->rtm_msglen; 224 rtm->rtm_seq = ++seq; 225 rtm->rtm_type = cmd; 226 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 227 if (errno != ESRCH && errno != EEXIST) { 228 warn("writing to routing socket"); 229 return (-1); 230 } 231 } 232 do { 233 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 234 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 235 if (l < 0) 236 warn("read from routing socket"); 237 return (0); 238 } 239