rtmsg.c revision 262435
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. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36/* 37 * from arp.c 8.2 (Berkeley) 1/2/94 38 */ 39 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: stable/10/libexec/bootpd/rtmsg.c 262435 2014-02-24 08:21:49Z brueffer $"); 42 43#include <sys/param.h> 44/* 45 * Verify that we are at least 4.4 BSD 46 */ 47#if defined(BSD) 48#if BSD >= 199306 49 50#include <sys/socket.h> 51#include <sys/filio.h> 52#include <sys/time.h> 53 54#include <net/if.h> 55#include <net/if_dl.h> 56#include <net/if_types.h> 57#include <net/route.h> 58 59#include <netinet/in.h> 60#include <netinet/if_ether.h> 61 62#include <arpa/inet.h> 63 64#include <errno.h> 65#include <stdio.h> 66#include <stdlib.h> 67#include <string.h> 68#include <syslog.h> 69#include <unistd.h> 70 71#include "report.h" 72 73 74static int rtmsg(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_in 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, 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_in *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 timespec tp; 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 = expire_time = 0; 137 138 /* make arp entry temporary */ 139 clock_gettime(CLOCK_MONOTONIC, &tp); 140 expire_time = tp.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_in *)(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_GATEWAY)) switch (sdl->sdl_type) { 152 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023: 153 case IFT_ISO88024: case IFT_ISO88025: 154 op = RTM_CHANGE; 155 goto overwrite; 156 } 157 if (doing_proxy == 0) { 158 report(LOG_WARNING, "set: can only proxy for %s\n", 159 inet_ntoa(sin->sin_addr)); 160 return (1); 161 } 162 goto tryagain; 163 } 164overwrite: 165 if (sdl->sdl_family != AF_LINK) { 166 report(LOG_WARNING, 167 "cannot intuit interface index and type for %s\n", 168 inet_ntoa(sin->sin_addr)); 169 return (1); 170 } 171 sdl_m.sdl_type = sdl->sdl_type; 172 sdl_m.sdl_index = sdl->sdl_index; 173 return (rtmsg(op)); 174} 175 176 177static int rtmsg(cmd) 178 int cmd; 179{ 180 static int seq; 181 int rlen; 182 register struct rt_msghdr *rtm = &m_rtmsg.m_rtm; 183 register char *cp = m_rtmsg.m_space; 184 register int l; 185 186 errno = 0; 187 bzero((char *)&m_rtmsg, sizeof(m_rtmsg)); 188 rtm->rtm_flags = flags; 189 rtm->rtm_version = RTM_VERSION; 190 191 switch (cmd) { 192 default: 193 report(LOG_ERR, "set_arp: internal wrong cmd - exiting"); 194 exit(1); 195 case RTM_ADD: 196 case RTM_CHANGE: 197 rtm->rtm_addrs |= RTA_GATEWAY; 198 rtm->rtm_rmx.rmx_expire = expire_time; 199 rtm->rtm_inits = RTV_EXPIRE; 200 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA); 201 if (doing_proxy) { 202 rtm->rtm_addrs |= RTA_NETMASK; 203 rtm->rtm_flags &= ~RTF_HOST; 204 } 205 /* FALLTHROUGH */ 206 case RTM_GET: 207 rtm->rtm_addrs |= RTA_DST; 208 } 209#define NEXTADDR(w, s) \ 210 if (rtm->rtm_addrs & (w)) { \ 211 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);} 212 213 NEXTADDR(RTA_DST, sin_m); 214 NEXTADDR(RTA_GATEWAY, sdl_m); 215 NEXTADDR(RTA_NETMASK, so_mask); 216 217 rtm->rtm_msglen = cp - (char *)&m_rtmsg; 218 219 l = rtm->rtm_msglen; 220 rtm->rtm_seq = ++seq; 221 rtm->rtm_type = cmd; 222 if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) { 223 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){ 224 report(LOG_WARNING, "writing to routing socket: %s", 225 strerror(errno)); 226 return (-1); 227 } 228 } 229 do { 230 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg)); 231 } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid())); 232 if (l < 0) 233 report(LOG_WARNING, "arp: read from routing socket: %s\n", 234 strerror(errno)); 235 return (0); 236} 237 238#endif /* BSD */ 239#endif /* BSD >= 199306 */ 240