usr/src/stand/lib/inet/icmp4.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1991-2003 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * icmp4.c, Code implementing the Internet Control Message Protocol (v4) ICMP.
  27  */
  28
  29 #pragma ident   "%Z%%M% %I%     %E% SMI"
  30
  31 #include <sys/types.h>
  32 #include <socket_impl.h>
  33 #include <socket_inet.h>
  34 #include <sys/salib.h>
  35 #include <sys/socket.h>
  36 #include <netinet/in_systm.h>
  37 #include <netinet/in.h>
  38 #include <netinet/ip.h>
  39 #include <netinet/udp.h>
  40 #include <netinet/ip_icmp.h>
  41 #include <sys/bootconf.h>
  42 #include <sys/fcntl.h>
  43
  44 #include "icmp4.h"
  45 #include "ipv4.h"
  46 #include "ipv4_impl.h"
  47 #include "mac.h"
  48 #include "v4_sum_impl.h"
  49 #include <sys/bootdebug.h>
  50
  51 /*
  52  * Handle ICMP redirects, ICMP echo messages. We only deal with redirects to a
  53  * different default router by changing the default route to the specified
  54  * value.
  55  */
  56 void
  57 icmp4(struct inetgram *igp, struct ip *iphp, uint16_t iphlen,
  58 struct in_addr ipsrc)
  59 {
  60         int             icmp_len;
  61         struct in_addr  our_ip;
  62         struct icmp     *icmphp;
  63
  64         icmp_len = ntohs(iphp->ip_len) - iphlen;
  65         if (icmp_len < ICMP_MINLEN) {
  66 #ifdef  DEBUG
  67                 printf("icmp4: ICMP message from %s is too short\n",
  68                     inet_ntoa(ipsrc));
  69 #endif  /* DEBUG */
  70                 return;
  71         }
  72
  73         icmphp = (struct icmp *)(igp->igm_mp->b_rptr + iphlen);
  74
  75         /* check alignment */
  76         if ((uintptr_t)icmphp % sizeof (uint16_t)) {
  77                 dprintf("icmp4: ICMP header not aligned (from %s)\n",
  78                     inet_ntoa(ipsrc));
  79                 return;
  80         }
  81         if (ipv4cksum((uint16_t *)icmphp, icmp_len) != 0) {
  82                 dprintf("icmp4: Bad ICMP checksum (from %s)\n",
  83                     inet_ntoa(ipsrc));
  84                 return;
  85         }
  86         switch (icmphp->icmp_type) {
  87         case ICMP_REDIRECT:
  88                 if (icmphp->icmp_code != ICMP_REDIRECT_HOST)
  89                         break;
  90                 dprintf("ICMP Redirect to gateway %s.\n",
  91                     inet_ntoa(icmphp->icmp_gwaddr));
  92                 if (ipv4_route(IPV4_ADD_ROUTE, RT_HOST, &icmphp->icmp_ip.ip_dst,
  93                     &icmphp->icmp_gwaddr) != 0) {
  94                         dprintf("icmp4: Cannot add route %s, %d\n",
  95                             inet_ntoa(icmphp->icmp_ip.ip_dst), errno);
  96                 }
  97                 break;
  98         case ICMP_UNREACH:
  99                 /*
 100                  * Need to highlight an error on the socket, and save the
 101                  * destination address so that we can ensure it is destined
 102                  * to this socket. We need the port number to be sure...
 103                  */
 104                 dprintf("ICMP destination unreachable (%s)\n",
 105                     inet_ntoa(icmphp->icmp_ip.ip_dst));
 106                 break;
 107         case ICMP_ECHO:
 108                 /*
 109                  * swap the source and destination IP addresses
 110                  * and send a reply right out.
 111                  */
 112                 ipv4_getipaddr(&our_ip);
 113                 if (our_ip.s_addr != INADDR_ANY) {
 114                         int                     s;
 115                         struct sockaddr_in      dest;
 116
 117                         if ((s = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
 118                                 dprintf("icmp4: socket: %d\n", errno);
 119                                 break;
 120                         }
 121                         icmphp->icmp_type = ICMP_ECHOREPLY;
 122                         icmphp->icmp_cksum = 0;
 123                         icmphp->icmp_cksum = ipv4cksum((uint16_t *)icmphp,
 124                             icmp_len);
 125                         dest.sin_family = AF_INET;
 126                         dest.sin_addr.s_addr = ipsrc.s_addr;
 127                         dest.sin_port = htons(0);
 128                         (void) sendto(s, (caddr_t)icmphp, icmp_len, 0,
 129                             (const struct sockaddr *)&dest, sizeof (dest));
 130                         (void) socket_close(s);
 131                 }
 132                 break;
 133         default:
 134                 dprintf("icmp4: Unsupported ICMP message type: 0x%x "
 135                     "received from %s\n", icmphp->icmp_type, inet_ntoa(ipsrc));
 136                 break;
 137         }
 138 }