rtmsg.c revision 6034
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 * $Id: rtmsg.c,v 1.2 1995/01/16 18:57:45 dfr Exp $ 43 */ 44 45#include <sys/param.h> 46/* 47 * Verify that we are at least 4.4 BSD 48 */ 49#if defined(BSD) 50#if BSD >= 199306 51 52#include <sys/socket.h> 53#include <sys/filio.h> 54 55#include <net/if.h> 56#include <net/if_dl.h> 57#include <net/if_types.h> 58#include <net/route.h> 59 60#include <netinet/in.h> 61#include <netinet/if_ether.h> 62 63#include <arpa/inet.h> 64 65#include <errno.h> 66#include <stdio.h> 67#include <string.h> 68#include <syslog.h> 69#include <unistd.h> 70 71#include "report.h" 72 73 74static int rtmsg __P((int)); 75 76static int s = -1; /* routing socket */ 77 78 79/* 80 * Open the routing socket 81 */ 82static void getsocket () { 83 if (s < 0) { 84 s = socket(PF_ROUTE, SOCK_RAW, 0); 85 if (s < 0) { 86 report(LOG_ERR, "socket %s", strerror(errno)); 87 exit(1); 88 } 89 } else { 90 /* 91 * Drain the socket of any unwanted routing messages. 92 */ 93 int n; 94 char buf[512]; 95 96 ioctl(s, FIONREAD, &n); 97 while (n > 0) { 98 read(s, buf, sizeof buf); 99 ioctl(s, FIONREAD, &n); 100 } 101 } 102} 103 104static struct sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}}; 105static struct sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m; 106static struct sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m; 107static int expire_time, flags, export_only, doing_proxy; 108static struct { 109 struct rt_msghdr m_rtm; 110 char m_space[512]; 111} m_rtmsg; 112 113/* 114 * Set an individual arp entry 115 */ 116int bsd_arp_set(ia, eaddr, len) 117 struct in_addr *ia; 118 char *eaddr; 119 int len; 120{ 121 register struct sockaddr_inarp *sin = &sin_m; 122 register struct sockaddr_dl *sdl; 123 register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm); 124 u_char *ea; 125 struct timeval time; 126 int op = RTM_ADD; 127 128 getsocket(); 129 sdl_m = blank_sdl; 130 sin_m = blank_sin; 131 sin->sin_addr = *ia; 132 133 ea = (u_char *)LLADDR(&sdl_m); 134 bcopy(eaddr, ea, len); 135 sdl_m.sdl_alen = len; 136 doing_proxy = flags = export_only = expire_time = 0; 137 138 /* make arp entry temporary */ 139 gettimeofday(&time, 0); 140 expire_time = time.tv_sec + 20 * 60; 141 142tryagain: 143 if (rtmsg(RTM_GET) < 0) { 144 report(LOG_WARNING, "rtmget: %s", strerror(errno)); 145 return (1); 146 } 147 sin = (struct sockaddr_inarp *)(rtm + 1); 148 sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin); 149 if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) { 150 if (sdl->sdl_family == AF_LINK && 151 (rtm->rtm_flags & RTF_LLINFO) && 152 !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) { 153 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 154 case IFT_ISO88024: case IFT_ISO88025: 155 op = RTM_CHANGE; 156 goto overwrite; 157 } 158 if (doing_proxy == 0) { 159 report(LOG_WARNING, "set: can only proxy for %s\n", 160 inet_ntoa(sin->sin_addr)); 161 return (1); 162 } 163 if (sin_m.sin_other & SIN_PROXY) { 164 report(LOG_WARNING, 165 "set: proxy entry exists for non 802 device\n"); 166 return(1); 167 } 168 sin_m.sin_other = SIN_PROXY; 169 export_only = 1; 170 goto tryagain; 171 } 172overwrite: 173 if (sdl->sdl_family != AF_LINK) { 174 report(LOG_WARNING, 175 "cannot intuit interface index and type for %s\n", 176 inet_ntoa(sin->sin_addr)); 177 return (1); 178 } 179 sdl_m.sdl_type = sdl->sdl_type; 180 sdl_m.sdl_index = sdl->sdl_index; 181 return (rtmsg(op)); 182} 183 184 185static int rtmsg(cmd) 186 int cmd; 187{ 188 static int seq; 189 int rlen; 190 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 191 register char *cp = m_rtmsg.m_space; 192 register int l; 193 194 errno = 0; 195 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 196 rtm->rtm_flags = flags; 197 rtm->rtm_version = RTM_VERSION; 198 199 switch (cmd) { 200 default: 201 report(LOG_ERR, "set_arp: internal wrong cmd - exiting"); 202 exit(1); 203 case RTM_ADD: 204 case RTM_CHANGE: 205 rtm->rtm_addrs |= RTA_GATEWAY; 206 rtm->rtm_rmx.rmx_expire = expire_time; 207 rtm->rtm_inits = RTV_EXPIRE; 208 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC); 209 sin_m.sin_other = 0; 210 if (doing_proxy) { 211 if (export_only) 212 sin_m.sin_other = SIN_PROXY; 213 else { 214 rtm->rtm_addrs |= RTA_NETMASK; 215 rtm->rtm_flags &= ~RTF_HOST; 216 } 217 } 218 /* FALLTHROUGH */ 219 case RTM_GET: 220 rtm->rtm_addrs |= RTA_DST; 221 } 222#define NEXTADDR(w, s) \ 223 if (rtm->rtm_addrs & (w)) { \ 224 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 225 226 NEXTADDR(RTA_DST, sin_m); 227 NEXTADDR(RTA_GATEWAY, sdl_m); 228 NEXTADDR(RTA_NETMASK, so_mask); 229 230 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 231 232 l = rtm->rtm_msglen; 233 rtm->rtm_seq = ++seq; 234 rtm->rtm_type = cmd; 235 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 236 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){ 237 report(LOG_WARNING, "writing to routing socket: %s", 238 strerror(errno)); 239 return (-1); 240 } 241 } 242 do { 243 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 244 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid())); 245 if (l < 0) 246 report(LOG_WARNING, "arp: read from routing socket: %s\n", 247 strerror(errno)); 248 return (0); 249} 250 251#endif /* BSD */ 252#endif /* BSD >= 199306 */ 253