1/*	$NetBSD: ethernet.c,v 1.3 2022/04/03 01:10:58 christos Exp $	*/
2
3/* ethernet.c
4
5   Packet assembly code, originally contributed by Archie Cobbs. */
6
7/*
8 * Copyright (C) 2004-2022 Internet Systems Consortium, Inc. ("ISC")
9 * Copyright (c) 1996-2003 by Internet Software Consortium
10 *
11 * This Source Code Form is subject to the terms of the Mozilla Public
12 * License, v. 2.0. If a copy of the MPL was not distributed with this
13 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
16 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
18 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
21 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22 *
23 *   Internet Systems Consortium, Inc.
24 *   PO Box 360
25 *   Newmarket, NH 03857 USA
26 *   <info@isc.org>
27 *   https://www.isc.org/
28 *
29 */
30
31#include <sys/cdefs.h>
32__RCSID("$NetBSD: ethernet.c,v 1.3 2022/04/03 01:10:58 christos Exp $");
33
34#include "dhcpd.h"
35
36#if defined (PACKET_ASSEMBLY) || defined (PACKET_DECODING)
37#include "includes/netinet/if_ether.h"
38#endif /* PACKET_ASSEMBLY || PACKET_DECODING */
39
40#if defined (PACKET_ASSEMBLY)
41/* Assemble an hardware header... */
42
43void assemble_ethernet_header (interface, buf, bufix, to)
44	struct interface_info *interface;
45	unsigned char *buf;
46	unsigned *bufix;
47	struct hardware *to;
48{
49	struct isc_ether_header eh;
50
51	if (to && to -> hlen == 7) /* XXX */
52		memcpy (eh.ether_dhost, &to -> hbuf [1],
53			sizeof eh.ether_dhost);
54	else
55		memset (eh.ether_dhost, 0xff, sizeof (eh.ether_dhost));
56	if (interface -> hw_address.hlen - 1 == sizeof (eh.ether_shost))
57		memcpy (eh.ether_shost, &interface -> hw_address.hbuf [1],
58			sizeof (eh.ether_shost));
59	else
60		memset (eh.ether_shost, 0x00, sizeof (eh.ether_shost));
61
62	eh.ether_type = htons (ETHERTYPE_IP);
63
64	memcpy (&buf [*bufix], &eh, ETHER_HEADER_SIZE);
65	*bufix += ETHER_HEADER_SIZE;
66}
67#endif /* PACKET_ASSEMBLY */
68
69#ifdef PACKET_DECODING
70/* Decode a hardware header... */
71
72ssize_t decode_ethernet_header (interface, buf, bufix, from)
73     struct interface_info *interface;
74     unsigned char *buf;
75     unsigned bufix;
76     struct hardware *from;
77{
78  struct isc_ether_header eh;
79
80  memcpy (&eh, buf + bufix, ETHER_HEADER_SIZE);
81
82#ifdef USERLAND_FILTER
83  if (ntohs (eh.ether_type) != ETHERTYPE_IP)
84	  return -1;
85#endif
86  memcpy (&from -> hbuf [1], eh.ether_shost, sizeof (eh.ether_shost));
87  from -> hbuf [0] = ARPHRD_ETHER;
88  from -> hlen = (sizeof eh.ether_shost) + 1;
89
90  return ETHER_HEADER_SIZE;
91}
92#endif /* PACKET_DECODING */
93