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. 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  * $FreeBSD: src/libexec/bootpd/rtmsg.c,v 1.10 1999/08/28 00:09:19 peter Exp $
  39  * $DragonFly: src/libexec/bootpd/rtmsg.c,v 1.4 2007/11/25 01:28:23 swildner Exp $
  40  */
  41
  42 #include <sys/param.h>
  43 /*
  44  * Verify that we are at least 4.4 BSD
  45  */
  46 #if defined(BSD)
  47 #if BSD >= 199306
  48
  49 #include <sys/socket.h>
  50 #include <sys/filio.h>
  51 #include <sys/time.h>
  52
  53 #include <net/if.h>
  54 #include <net/if_dl.h>
  55 #include <net/if_types.h>
  56 #include <net/route.h>
  57
  58 #include <netinet/in.h>
  59 #include <netinet/if_ether.h>
  60
  61 #include <arpa/inet.h>
  62
  63 #include <errno.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67 #include <syslog.h>
  68 #include <unistd.h>
  69
  70 #include "report.h"
  71
  72
  73 static int rtmsg (int);
  74
  75 static int s = -1;      /* routing socket */
  76
  77
  78 /*
  79  * Open the routing socket
  80  */
  81 static void
  82 getsocket(void)
  83 {
  84         if (s < 0) {
  85                 s = socket(PF_ROUTE, SOCK_RAW, 0);
  86                 if (s < 0) {
  87                         report(LOG_ERR, "socket %s", strerror(errno));
  88                         exit(1);
  89                 }
  90         } else {
  91                 /*
  92                  * Drain the socket of any unwanted routing messages.
  93                  */
  94                 int n;
  95                 char buf[512];
  96
  97                 ioctl(s, FIONREAD, &n);
  98                 while (n > 0) {
  99                         read(s, buf, sizeof buf);
 100                         ioctl(s, FIONREAD, &n);
 101                 }
 102         }
 103 }
 104
 105 static struct   sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
 106 static struct   sockaddr_inarp blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
 107 static struct   sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
 108 static int      expire_time, flags, export_only, doing_proxy;
 109 static struct   {
 110         struct  rt_msghdr m_rtm;
 111         char    m_space[512];
 112 }       m_rtmsg;
 113
 114 /*
 115  * Set an individual arp entry
 116  */
 117 int
 118 bsd_arp_set(struct in_addr *ia, char *eaddr, int len)
 119 {
 120         struct sockaddr_inarp *sin = &sin_m;
 121         struct sockaddr_dl *sdl;
 122         struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
 123         u_char *ea;
 124         struct timespec tp;
 125         int op = RTM_ADD;
 126
 127         getsocket();
 128         sdl_m = blank_sdl;
 129         sin_m = blank_sin;
 130         sin->sin_addr = *ia;
 131
 132         ea = (u_char *)LLADDR(&sdl_m);
 133         bcopy(eaddr, ea, len);
 134         sdl_m.sdl_alen = len;
 135         doing_proxy = flags = export_only = expire_time = 0;
 136
 137         /* make arp entry temporary */
 138         clock_gettime(CLOCK_MONOTONIC, &tp);
 139         expire_time = tp.tv_sec + 20 * 60;
 140
 141 tryagain:
 142         if (rtmsg(RTM_GET) < 0) {
 143                 report(LOG_WARNING, "rtmget: %s", strerror(errno));
 144                 return (1);
 145         }
 146         sin = (struct sockaddr_inarp *)(rtm + 1);
 147         sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
 148         if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
 149                 if (sdl->sdl_family == AF_LINK &&
 150                     (rtm->rtm_flags & RTF_LLINFO) &&
 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                 if (sin_m.sin_other & SIN_PROXY) {
 163                         report(LOG_WARNING,
 164                                 "set: proxy entry exists for non 802 device\n");
 165                         return(1);
 166                 }
 167                 sin_m.sin_other = SIN_PROXY;
 168                 export_only = 1;
 169                 goto tryagain;
 170         }
 171 overwrite:
 172         if (sdl->sdl_family != AF_LINK) {
 173                 report(LOG_WARNING,
 174                         "cannot intuit interface index and type for %s\n",
 175                         inet_ntoa(sin->sin_addr));
 176                 return (1);
 177         }
 178         sdl_m.sdl_type = sdl->sdl_type;
 179         sdl_m.sdl_index = sdl->sdl_index;
 180         return (rtmsg(op));
 181 }
 182
 183
 184 static int
 185 rtmsg(int cmd)
 186 {
 187         static int seq;
 188         int rlen;
 189         struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
 190         char *cp = m_rtmsg.m_space;
 191         int l;
 192
 193         errno = 0;
 194         bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
 195         rtm->rtm_flags = flags;
 196         rtm->rtm_version = RTM_VERSION;
 197
 198         switch (cmd) {
 199         default:
 200                 report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
 201                 exit(1);
 202         case RTM_ADD:
 203         case RTM_CHANGE:
 204                 rtm->rtm_addrs |= RTA_GATEWAY;
 205                 rtm->rtm_rmx.rmx_expire = expire_time;
 206                 rtm->rtm_inits = RTV_EXPIRE;
 207                 rtm->rtm_flags |= (RTF_HOST | RTF_STATIC);
 208                 sin_m.sin_other = 0;
 209                 if (doing_proxy) {
 210                         if (export_only)
 211                                 sin_m.sin_other = SIN_PROXY;
 212                         else {
 213                                 rtm->rtm_addrs |= RTA_NETMASK;
 214                                 rtm->rtm_flags &= ~RTF_HOST;
 215                         }
 216                 }
 217                 /* FALLTHROUGH */
 218         case RTM_GET:
 219                 rtm->rtm_addrs |= RTA_DST;
 220         }
 221 #define NEXTADDR(w, s) \
 222         if (rtm->rtm_addrs & (w)) { \
 223                 bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}
 224
 225         NEXTADDR(RTA_DST, sin_m);
 226         NEXTADDR(RTA_GATEWAY, sdl_m);
 227         NEXTADDR(RTA_NETMASK, so_mask);
 228
 229         rtm->rtm_msglen = cp - (char *)&m_rtmsg;
 230
 231         l = rtm->rtm_msglen;
 232         rtm->rtm_seq = ++seq;
 233         rtm->rtm_type = cmd;
 234         if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
 235                 if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
 236                         report(LOG_WARNING, "writing to routing socket: %s",
 237                                 strerror(errno));
 238                         return (-1);
 239                 }
 240         }
 241         do {
 242                 l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
 243         } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
 244         if (l < 0)
 245                 report(LOG_WARNING, "arp: read from routing socket: %s\n",
 246                     strerror(errno));
 247         return (0);
 248 }
 249
 250 #endif /* BSD */
 251 #endif /* BSD >= 199306 */