1/*-
2 * Copyright (c) 1982, 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	@(#)if_ethersubr.c	8.1 (Berkeley) 6/10/93
30 * $FreeBSD: src/sys/net/if_ethersubr.c,v 1.193.2.12 2006/08/28 02:54:14 thompsa Exp $
31 */
32
33#include <stdio.h>
34#include <sys/types.h>
35#include <sys/mbuf.h>
36#include <net/ethernet.h>
37#include <net/if_vlan_var.h>
38#include <netinet/in.h>
39
40#if 0
41/*
42 * This is for reference.  We have a table-driven version
43 * of the little-endian crc32 generator, which is faster
44 * than the double-loop.
45 */
46uint32_t
47ether_crc32_le(const uint8_t *buf, size_t len)
48{
49	size_t i;
50	uint32_t crc;
51	int bit;
52	uint8_t data;
53
54	crc = 0xffffffff;	/* initial value */
55
56	for (i = 0; i < len; i++) {
57		for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1)
58			carry = (crc ^ data) & 1;
59			crc >>= 1;
60			if (carry)
61				crc = (crc ^ ETHER_CRC_POLY_LE);
62	}
63
64	return (crc);
65}
66#else
67uint32_t
68ether_crc32_le(const uint8_t *buf, size_t len)
69{
70	static const uint32_t crctab[] = {
71		0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
72		0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
73		0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
74		0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
75	};
76	size_t i;
77	uint32_t crc;
78
79	crc = 0xffffffff;	/* initial value */
80
81	for (i = 0; i < len; i++) {
82		crc ^= buf[i];
83		crc = (crc >> 4) ^ crctab[crc & 0xf];
84		crc = (crc >> 4) ^ crctab[crc & 0xf];
85	}
86
87	return (crc);
88}
89#endif
90
91uint32_t
92ether_crc32_be(const uint8_t *buf, size_t len)
93{
94	size_t i;
95	uint32_t crc, carry;
96	int bit;
97	uint8_t data;
98
99	crc = 0xffffffff;	/* initial value */
100
101	for (i = 0; i < len; i++) {
102		for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
103			carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
104			crc <<= 1;
105			if (carry)
106				crc = (crc ^ ETHER_CRC_POLY_BE) | carry;
107		}
108	}
109
110	return (crc);
111}
112
113char *
114ether_sprintf(const u_char *ap)
115{
116	static char etherbuf[18];
117	snprintf(etherbuf, sizeof (etherbuf),
118		"%02x:%02x:%02x:%02x:%02x:%02x",
119		(unsigned)ap[0], (unsigned)ap[1], (unsigned)ap[2],
120		(unsigned)ap[3], (unsigned)ap[4], (unsigned)ap[5]);
121	return (etherbuf);
122}
123
124struct mbuf *
125ether_vlanencap(struct mbuf *m, uint16_t tag)
126{
127	struct ether_vlan_header *evl;
128
129	M_PREPEND(m, ETHER_VLAN_ENCAP_LEN, M_NOWAIT);
130	if (m == NULL)
131		return (NULL);
132	/* M_PREPEND takes care of m_len, m_pkthdr.len for us */
133
134	if (m->m_len < sizeof(*evl)) {
135		m = m_pullup(m, sizeof(*evl));
136		if (m == NULL)
137			return (NULL);
138	}
139
140	/*
141	 * Transform the Ethernet header into an Ethernet header
142	 * with 802.1Q encapsulation.
143	 */
144	evl = mtod(m, struct ether_vlan_header *);
145	bcopy((char *)evl + ETHER_VLAN_ENCAP_LEN,
146	    (char *)evl, ETHER_HDR_LEN - ETHER_TYPE_LEN);
147	evl->evl_encap_proto = htons(ETHERTYPE_VLAN);
148	evl->evl_tag = htons(tag);
149	return (m);
150}
151