contrib/dhcp-3.0/common/ethernet.c

   1 /* ethernet.c
   2
   3    Packet assembly code, originally contributed by Archie Cobbs. */
   4
   5 /*
   6  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   7  * Copyright (c) 1996-2003 by Internet Software Consortium
   8  *
   9  * Permission to use, copy, modify, and distribute this software for any
  10  * purpose with or without fee is hereby granted, provided that the above
  11  * copyright notice and this permission notice appear in all copies.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  19  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20  *
  21  *   Internet Systems Consortium, Inc.
  22  *   950 Charter Street
  23  *   Redwood City, CA 94063
  24  *   <info@isc.org>
  25  *   http://www.isc.org/
  26  *
  27  * This software has been written for Internet Systems Consortium
  28  * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
  29  * To learn more about Internet Systems Consortium, see
  30  * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
  31  * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
  32  * ``http://www.nominum.com''.
  33  */
  34
  35 #ifndef lint
  36 static char copyright[] =
  37 "$Id: ethernet.c,v 1.6.2.3 2004/06/10 17:59:17 dhankins Exp $ Copyright (c) 2004 Internet Systems Consortium.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 #include "dhcpd.h"
  41
  42 #if defined (PACKET_ASSEMBLY) || defined (PACKET_DECODING)
  43 #include "includes/netinet/if_ether.h"
  44 #endif /* PACKET_ASSEMBLY || PACKET_DECODING */
  45
  46 #if defined (PACKET_ASSEMBLY)
  47 /* Assemble an hardware header... */
  48
  49 void assemble_ethernet_header (interface, buf, bufix, to)
  50         struct interface_info *interface;
  51         unsigned char *buf;
  52         unsigned *bufix;
  53         struct hardware *to;
  54 {
  55         struct isc_ether_header eh;
  56
  57         if (to && to -> hlen == 7) /* XXX */
  58                 memcpy (eh.ether_dhost, &to -> hbuf [1],
  59                         sizeof eh.ether_dhost);
  60         else
  61                 memset (eh.ether_dhost, 0xff, sizeof (eh.ether_dhost));
  62         if (interface -> hw_address.hlen - 1 == sizeof (eh.ether_shost))
  63                 memcpy (eh.ether_shost, &interface -> hw_address.hbuf [1],
  64                         sizeof (eh.ether_shost));
  65         else
  66                 memset (eh.ether_shost, 0x00, sizeof (eh.ether_shost));
  67
  68         eh.ether_type = htons (ETHERTYPE_IP);
  69
  70         memcpy (&buf [*bufix], &eh, ETHER_HEADER_SIZE);
  71         *bufix += ETHER_HEADER_SIZE;
  72 }
  73 #endif /* PACKET_ASSEMBLY */
  74
  75 #ifdef PACKET_DECODING
  76 /* Decode a hardware header... */
  77
  78 ssize_t decode_ethernet_header (interface, buf, bufix, from)
  79      struct interface_info *interface;
  80      unsigned char *buf;
  81      unsigned bufix;
  82      struct hardware *from;
  83 {
  84   struct isc_ether_header eh;
  85
  86   memcpy (&eh, buf + bufix, ETHER_HEADER_SIZE);
  87
  88 #ifdef USERLAND_FILTER
  89   if (ntohs (eh.ether_type) != ETHERTYPE_IP)
  90           return -1;
  91 #endif
  92   memcpy (&from -> hbuf [1], eh.ether_shost, sizeof (eh.ether_shost));
  93   from -> hbuf [0] = ARPHRD_ETHER;
  94   from -> hlen = (sizeof eh.ether_shost) + 1;
  95
  96   return ETHER_HEADER_SIZE;
  97 }
  98 #endif /* PACKET_DECODING */