mkarp.c revision 1.10
1 /* $NetBSD: mkarp.c,v 1.10 2014/12/03 03:44:45 christos 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\ 38 The Regents of the University of California. All rights reserved."); 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 1.10 2014/12/03 03:44:45 christos 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 static 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 = { 97 .sin_len = sizeof(blank_sin), 98 .sin_family = AF_INET, 99 }; 100 static struct sockaddr_dl blank_sdl = { 101 .sdl_len = sizeof(blank_sdl), 102 .sdl_family = AF_LINK, 103 }; 104 105 struct sockaddr_inarp *sin; 106 struct sockaddr_dl *sdl; 107 struct rt_msghdr *rtm; 108 u_int8_t *p, *endp; 109 int result; 110 int s; 111 112 struct sockaddr_inarp sin_m; 113 struct sockaddr_dl sdl_m; 114 115 sin = &sin_m; 116 rtm = &(m_rtmsg.m_rtm); 117 118 sdl_m = blank_sdl; /* struct copy */ 119 sin_m = blank_sin; /* struct copy */ 120 121 sin->sin_addr.s_addr = ipaddr; 122 123 p = LLADDR(&sdl_m); 124 endp = ((caddr_t)&sdl_m) + sdl_m.sdl_len; 125 if (endp > (p + ETHER_ADDR_LEN)) 126 endp = p + ETHER_ADDR_LEN; 127 128 while (p < endp) { 129 *p++ = *haddr++; 130 } 131 sdl_m.sdl_alen = ETHER_ADDR_LEN; 132 133 /* 134 * We need to close and open the socket to prevent routing updates 135 * building up such that when we send our message we never see our 136 * reply (and hang) 137 */ 138 s = socket(PF_ROUTE, SOCK_RAW, 0); 139 if (s < 0) 140 err(1, "socket"); 141 142 rtm->rtm_flags = 0; 143 144 if (rtmsg(RTM_GET, s, rtm, &sin_m, &sdl_m) < 0) { 145 #if 0 146 warn("%s", host); 147 #endif 148 close(s); 149 return (1); 150 } 151 sin = (struct sockaddr_inarp *)(rtm + 1); 152 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 153 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 154 if (sdl->sdl_family == AF_LINK && 155 (rtm->rtm_flags & RTF_LLINFO) && 156 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 157 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 158 case IFT_ISO88024: case IFT_ISO88025: case IFT_ARCNET: 159 goto overwrite; 160 } 161 #if 0 162 (void)printf("set: can only proxy for %s\n", host); 163 #endif 164 close(s); 165 return (1); 166 } 167 overwrite: 168 if (sdl->sdl_family != AF_LINK) { 169 #if 0 170 (void)printf("cannot intuit interface index and type for %s\n", 171 host); 172 #endif 173 close(s); 174 return (1); 175 } 176 sdl_m.sdl_type = sdl->sdl_type; 177 sdl_m.sdl_index = sdl->sdl_index; 178 result = rtmsg(RTM_ADD, s, rtm, &sin_m, &sdl_m); 179 close(s); 180 return (result); 181 } 182 183 int 184 rtmsg(int cmd, int s, struct rt_msghdr *rtm, struct sockaddr_inarp *sin_m, 185 struct sockaddr_dl *sdl_m) 186 { 187 static int seq; 188 int rlen; 189 char *cp; 190 int l; 191 pid_t pid; 192 struct timeval tv; 193 194 rtm = &m_rtmsg.m_rtm; 195 cp = m_rtmsg.m_space; 196 errno = 0; 197 198 pid = getpid(); 199 200 (void)memset(&m_rtmsg, 0, sizeof(m_rtmsg)); 201 rtm->rtm_version = RTM_VERSION; 202 203 switch (cmd) { 204 default: 205 errx(1, "internal wrong cmd"); 206 /*NOTREACHED*/ 207 case RTM_ADD: 208 rtm->rtm_addrs |= RTA_GATEWAY; 209 (void)gettimeofday(&tv, 0); 210 rtm->rtm_rmx.rmx_expire = tv.tv_sec + 20 * 60; 211 rtm->rtm_inits = RTV_EXPIRE; 212 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 213 sin_m->sin_other = 0; 214 215 /* FALLTHROUGH */ 216 case RTM_GET: 217 rtm->rtm_addrs |= RTA_DST; 218 } 219 #define NEXTADDR(w, s) \ 220 if (rtm->rtm_addrs & (w)) { \ 221 (void)memcpy(cp, s, ((struct sockaddr *)s)->sa_len); \ 222 cp += ROUNDUP(((struct sockaddr *)s)->sa_len);} 223 224 NEXTADDR(RTA_DST, sin_m); 225 NEXTADDR(RTA_GATEWAY, sdl_m); 226 227 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 228 229 l = rtm->rtm_msglen; 230 rtm->rtm_seq = ++seq; 231 rtm->rtm_type = cmd; 232 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 233 if (errno != ESRCH && errno != EEXIST) { 234 warn("writing to routing socket"); 235 return (-1); 236 } 237 } 238 do { 239 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 240 } while (l > 0 && (rtm->rtm_seq != seq || rtm->rtm_pid != pid)); 241 if (l < 0) 242 warn("read from routing socket"); 243 return (0); 244 } 245
Indexes created Fri Sep 26 20:09:58 GMT 2025