rtmsg.c revision 190601
1/* 2 * Copyright (c) 1984, 1993 3 * The Regents of the University of California. All rights reserved. 4 * Copyright (c) 1994 5 * Geoffrey M. Rehmet, All rights reserved. 6 * 7 * This code is derived from software which forms part of the 4.4-Lite 8 * Berkeley software distribution, which was in derived from software 9 * contributed to Berkeley by Sun Microsystems, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40/* 41 * from arp.c 8.2 (Berkeley) 1/2/94 42 */ 43 44#include <sys/cdefs.h> 45__FBSDID("$FreeBSD: head/libexec/bootpd/rtmsg.c 190601 2009-03-31 23:02:51Z cognet $"); 46 47#include <sys/param.h> 48/* 49 * Verify that we are at least 4.4 BSD 50 */ 51#if defined(BSD) 52#if BSD >= 199306 53 54#include <sys/socket.h> 55#include <sys/filio.h> 56#include <sys/time.h> 57 58#include <net/if.h> 59#include <net/if_dl.h> 60#include <net/if_types.h> 61#include <net/route.h> 62 63#include <netinet/in.h> 64#include <netinet/if_ether.h> 65 66#include <arpa/inet.h> 67 68#include <errno.h> 69#include <stdio.h> 70#include <stdlib.h> 71#include <string.h> 72#include <syslog.h> 73#include <unistd.h> 74 75#include "report.h" 76 77 78static int rtmsg(int); 79 80static int s = -1; /* routing socket */ 81 82 83/* 84 * Open the routing socket 85 */ 86static void getsocket () { 87 if (s < 0) { 88 s = socket(PF_ROUTE, SOCK_RAW, 0); 89 if (s < 0) { 90 report(LOG_ERR, "socket %s", strerror(errno)); 91 exit(1); 92 } 93 } else { 94 /* 95 * Drain the socket of any unwanted routing messages. 96 */ 97 int n; 98 char buf[512]; 99 100 ioctl(s, FIONREAD, &n); 101 while (n > 0) { 102 read(s, buf, sizeof buf); 103 ioctl(s, FIONREAD, &n); 104 } 105 } 106} 107 108static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 109static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 110static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 111static int expire_time, flags, export_only, doing_proxy; 112static struct { 113 struct rt_msghdr m_rtm; 114 char m_space[512]; 115} m_rtmsg; 116 117/* 118 * Set an individual arp entry 119 */ 120int bsd_arp_set(ia, eaddr, len) 121 struct in_addr *ia; 122 char *eaddr; 123 int len; 124{ 125 register struct sockaddr_inarp *sin = &sin_m; 126 register struct sockaddr_dl *sdl; 127 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 128 u_char *ea; 129 struct timeval time; 130 int op = RTM_ADD; 131 132 getsocket(); 133 sdl_m = blank_sdl; 134 sin_m = blank_sin; 135 sin->sin_addr = *ia; 136 137 ea = (u_char *)LLADDR(&sdl_m); 138 bcopy(eaddr, ea, len); 139 sdl_m.sdl_alen = len; 140 doing_proxy = flags = export_only = expire_time = 0; 141 142 /* make arp entry temporary */ 143 gettimeofday(&time, 0); 144 expire_time = time.tv_sec + 20 * 60; 145 146tryagain: 147 if (rtmsg(RTM_GET) < 0) { 148 report(LOG_WARNING, "rtmget: %s", strerror(errno)); 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_GATEWAY)) switch (sdl->sdl_type) { 156 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 157 case IFT_ISO88024: case IFT_ISO88025: 158 op = RTM_CHANGE; 159 goto overwrite; 160 } 161 if (doing_proxy == 0) { 162 report(LOG_WARNING, "set: can only proxy for %s\n", 163 inet_ntoa(sin->sin_addr)); 164 return (1); 165 } 166 if (sin_m.sin_other & SIN_PROXY) { 167 report(LOG_WARNING, 168 "set: proxy entry exists for non 802 device\n"); 169 return(1); 170 } 171 sin_m.sin_other = SIN_PROXY; 172 export_only = 1; 173 goto tryagain; 174 } 175overwrite: 176 if (sdl->sdl_family != AF_LINK) { 177 report(LOG_WARNING, 178 "cannot intuit interface index and type for %s\n", 179 inet_ntoa(sin->sin_addr)); 180 return (1); 181 } 182 sdl_m.sdl_type = sdl->sdl_type; 183 sdl_m.sdl_index = sdl->sdl_index; 184 return (rtmsg(op)); 185} 186 187 188static int rtmsg(cmd) 189 int cmd; 190{ 191 static int seq; 192 int rlen; 193 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 194 register char *cp = m_rtmsg.m_space; 195 register int l; 196 197 errno = 0; 198 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 199 rtm->rtm_flags = flags; 200 rtm->rtm_version = RTM_VERSION; 201 202 switch (cmd) { 203 default: 204 report(LOG_ERR, "set_arp: internal wrong cmd - exiting"); 205 exit(1); 206 case RTM_ADD: 207 case RTM_CHANGE: 208 rtm->rtm_addrs |= RTA_GATEWAY; 209 rtm->rtm_rmx.rmx_expire = expire_time; 210 rtm->rtm_inits = RTV_EXPIRE; 211 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 212 sin_m.sin_other = 0; 213 if (doing_proxy) { 214 if (export_only) 215 sin_m.sin_other = SIN_PROXY; 216 else { 217 rtm->rtm_addrs |= RTA_NETMASK; 218 rtm->rtm_flags &= ~RTF_HOST; 219 } 220 } 221 /* FALLTHROUGH */ 222 case RTM_GET: 223 rtm->rtm_addrs |= RTA_DST; 224 } 225#define NEXTADDR(w, s) \ 226 if (rtm->rtm_addrs & (w)) { \ 227 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 228 229 NEXTADDR(RTA_DST, sin_m); 230 NEXTADDR(RTA_GATEWAY, sdl_m); 231 NEXTADDR(RTA_NETMASK, so_mask); 232 233 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 234 235 l = rtm->rtm_msglen; 236 rtm->rtm_seq = ++seq; 237 rtm->rtm_type = cmd; 238 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 239 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){ 240 report(LOG_WARNING, "writing to routing socket: %s", 241 strerror(errno)); 242 return (-1); 243 } 244 } 245 do { 246 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 247 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid())); 248 if (l < 0) 249 report(LOG_WARNING, "arp: read from routing socket: %s\n", 250 strerror(errno)); 251 return (0); 252} 253 254#endif /* BSD */ 255#endif /* BSD >= 199306 */ 256