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
assemble_ethernet_header(interface,buf,bufix,to)43 void 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
decode_ethernet_header(interface,buf,bufix,from)72 ssize_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