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 1.4 2007/11/25 01:28:23 swildner 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 <stdlib.h>
  70 #include <string.h>
  71 #include <syslog.h>
  72 #include <unistd.h>
  73
  74 #include "report.h"
  75
  76
  77 static int rtmsg (int);
  78
  79 static int s = -1;      /* routing socket */
  80
  81
  82 /*
  83  * Open the routing socket
  84  */
  85 static void getsocket () {
  86         if (s < 0) {
  87                 s = socket(PF_ROUTE, SOCK_RAW, 0);
  88                 if (s < 0) {
  89                         report(LOG_ERR, "socket %s", strerror(errno));
  90                         exit(1);
  91                 }
  92         } else {
  93                 /*
  94                  * Drain the socket of any unwanted routing messages.
  95                  */
  96                 int n;
  97                 char buf[512];
  98
  99                 ioctl(s, FIONREAD, &n);
 100                 while (n > 0) {
 101                         read(s, buf, sizeof buf);
 102                         ioctl(s, FIONREAD, &n);
 103                 }
 104         }
 105 }
 106
 107 static struct   sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
 108 static struct   sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
 109 static struct   sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
 110 static int      expire_time, flags, export_only, doing_proxy;
 111 static struct   {
 112         struct  rt_msghdr m_rtm;
 113         char    m_space[512];
 114 }       m_rtmsg;
 115
 116 /*
 117  * Set an individual arp entry
 118  */
 119 int bsd_arp_set(ia, eaddr, len)
 120         struct in_addr *ia;
 121         char *eaddr;
 122         int len;
 123 {
 124         register struct sockaddr_inarp *sin = &sin_m;
 125         register struct sockaddr_dl *sdl;
 126         register struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
 127         u_char *ea;
 128         struct timeval time;
 129         int op = RTM_ADD;
 130
 131         getsocket();
 132         sdl_m = blank_sdl;
 133         sin_m = blank_sin;
 134         sin->sin_addr = *ia;
 135
 136         ea = (u_char *)LLADDR(&sdl_m);
 137         bcopy(eaddr, ea, len);
 138         sdl_m.sdl_alen = len;
 139         doing_proxy = flags = export_only = expire_time = 0;
 140
 141         /* make arp entry temporary */
 142         gettimeofday(&time, 0);
 143         expire_time = time.tv_sec + 20 * 60;
 144
 145 tryagain:
 146         if (rtmsg(RTM_GET) < 0) {
 147                 report(LOG_WARNING, "rtmget: %s", strerror(errno));
 148                 return (1);
 149         }
 150         sin = (struct sockaddr_inarp *)(rtm + 1);
 151         sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
 152         if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
 153                 if (sdl->sdl_family == AF_LINK &&
 154                     (rtm->rtm_flags & RTF_LLINFO) &&
 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         }
 175 overwrite:
 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
 188 static 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);
 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 */