libexec/bootpd/rtmsg.c

   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  * $FreeBSD: src/libexec/bootpd/rtmsg.c,v 1.10 1999/08/28 00:09:19 peter Exp $
  43  * $DragonFly: src/libexec/bootpd/rtmsg.c,v 1.3 2003/11/14 04:54:29 dillon Exp $
  44  */
  45
  46 #include <sys/param.h>
  47 /*
  48  * Verify that we are at least 4.4 BSD
  49  */
  50 #if defined(BSD)
  51 #if BSD >= 199306
  52
  53 #include <sys/socket.h>
  54 #include <sys/filio.h>
  55 #include <sys/time.h>
  56
  57 #include <net/if.h>
  58 #include <net/if_dl.h>
  59 #include <net/if_types.h>
  60 #include <net/route.h>
  61
  62 #include <netinet/in.h>
  63 #include <netinet/if_ether.h>
  64
  65 #include <arpa/inet.h>
  66
  67 #include <errno.h>
  68 #include <stdio.h>
  69 #include <string.h>
  70 #include <syslog.h>
  71 #include <unistd.h>
  72
  73 #include "report.h"
  74
  75
  76 static int rtmsg (int);
  77
  78 static int s = -1;      /* routing socket */
  79
  80
  81 /*
  82  * Open the routing socket
  83  */
  84 static void getsocket () {
  85         if (s < 0) {
  86                 s = socket(PF_ROUTE, SOCK_RAW, 0);
  87                 if (s < 0) {
  88                         report(LOG_ERR, "socket %s", strerror(errno));
  89                         exit(1);
  90                 }
  91         } else {
  92                 /*
  93                  * Drain the socket of any unwanted routing messages.
  94                  */
  95                 int n;
  96                 char buf[512];
  97
  98                 ioctl(s, FIONREAD, &n);
  99                 while (n > 0) {
 100                         read(s, buf, sizeof buf);
 101                         ioctl(s, FIONREAD, &n);
 102                 }
 103         }
 104 }
 105
 106 static struct   sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
 107 static struct   sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
 108 static struct   sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
 109 static int      expire_time, flags, export_only, doing_proxy;
 110 static struct   {
 111         struct  rt_msghdr m_rtm;
 112         char    m_space[512];
 113 }       m_rtmsg;
 114
 115 /*
 116  * Set an individual arp entry
 117  */
 118 int bsd_arp_set(ia, eaddr, len)
 119         struct in_addr *ia;
 120         char *eaddr;
 121         int len;
 122 {
 123         register struct sockaddr_inarp *sin = &sin_m;
 124         register struct sockaddr_dl *sdl;
 125         register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
 126         u_char *ea;
 127         struct timeval time;
 128         int op = RTM_ADD;
 129
 130         getsocket();
 131         sdl_m = blank_sdl;
 132         sin_m = blank_sin;
 133         sin->sin_addr = *ia;
 134
 135         ea = (u_char *)LLADDR(&sdl_m);
 136         bcopy(eaddr, ea, len);
 137         sdl_m.sdl_alen = len;
 138         doing_proxy = flags = export_only = expire_time = 0;
 139
 140         /* make arp entry temporary */
 141         gettimeofday(&time, 0);
 142         expire_time = time.tv_sec + 20 * 60;
 143
 144 tryagain:
 145         if (rtmsg(RTM_GET) < 0) {
 146                 report(LOG_WARNING, "rtmget: %s", strerror(errno));
 147                 return (1);
 148         }
 149         sin = (struct sockaddr_inarp *)(rtm + 1);
 150         sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
 151         if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
 152                 if (sdl->sdl_family == AF_LINK &&
 153                     (rtm->rtm_flags & RTF_LLINFO) &&
 154                     !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
 155                 case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
 156                 case IFT_ISO88024: case IFT_ISO88025:
 157                         op = RTM_CHANGE;
 158                         goto overwrite;
 159                 }
 160                 if (doing_proxy == 0) {
 161                         report(LOG_WARNING, "set: can only proxy for %s\n",
 162                                 inet_ntoa(sin->sin_addr));
 163                         return (1);
 164                 }
 165                 if (sin_m.sin_other & SIN_PROXY) {
 166                         report(LOG_WARNING,
 167                                 "set: proxy entry exists for non 802 device\n");
 168                         return(1);
 169                 }
 170                 sin_m.sin_other = SIN_PROXY;
 171                 export_only = 1;
 172                 goto tryagain;
 173         }
 174 overwrite:
 175         if (sdl->sdl_family != AF_LINK) {
 176                 report(LOG_WARNING,
 177                         "cannot intuit interface index and type for %s\n",
 178                         inet_ntoa(sin->sin_addr));
 179                 return (1);
 180         }
 181         sdl_m.sdl_type = sdl->sdl_type;
 182         sdl_m.sdl_index = sdl->sdl_index;
 183         return (rtmsg(op));
 184 }
 185
 186
 187 static int rtmsg(cmd)
 188         int cmd;
 189 {
 190         static int seq;
 191         int rlen;
 192         register struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
 193         register char *cp = m_rtmsg.m_space;
 194         register int l;
 195
 196         errno = 0;
 197         bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
 198         rtm->rtm_flags = flags;
 199         rtm->rtm_version = RTM_VERSION;
 200
 201         switch (cmd) {
 202         default:
 203                 report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
 204                 exit(1);
 205         case RTM_ADD:
 206         case RTM_CHANGE:
 207                 rtm->rtm_addrs |= RTA_GATEWAY;
 208                 rtm->rtm_rmx.rmx_expire = expire_time;
 209                 rtm->rtm_inits = RTV_EXPIRE;
 210                 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
 211                 sin_m.sin_other = 0;
 212                 if (doing_proxy) {
 213                         if (export_only)
 214                                 sin_m.sin_other = SIN_PROXY;
 215                         else {
 216                                 rtm->rtm_addrs |= RTA_NETMASK;
 217                                 rtm->rtm_flags &= ~RTF_HOST;
 218                         }
 219                 }
 220                 /* FALLTHROUGH */
 221         case RTM_GET:
 222                 rtm->rtm_addrs |= RTA_DST;
 223         }
 224 #define NEXTADDR(w, s) \
 225         if (rtm->rtm_addrs & (w)) { \
 226                 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
 227
 228         NEXTADDR(RTA_DST, sin_m);
 229         NEXTADDR(RTA_GATEWAY, sdl_m);
 230         NEXTADDR(RTA_NETMASK, so_mask);
 231
 232         rtm->rtm_msglen = cp - (char *)&m_rtmsg;
 233
 234         l = rtm->rtm_msglen;
 235         rtm->rtm_seq = ++seq;
 236         rtm->rtm_type = cmd;
 237         if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
 238                 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
 239                         report(LOG_WARNING, "writing to routing socket: %s",
 240                                 strerror(errno));
 241                         return (-1);
 242                 }
 243         }
 244         do {
 245                 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
 246         } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
 247         if (l < 0)
 248                 report(LOG_WARNING, "arp: read from routing socket: %s\n",
 249                     strerror(errno));
 250         return (0);
 251 }
 252
 253 #endif /* BSD */
 254 #endif /* BSD >= 199306 */