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 */
46 uint32_t
47 ether_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
67 uint32_t
ether_crc32_le(const uint8_t * buf,size_t len)68 ether_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
91 uint32_t
ether_crc32_be(const uint8_t * buf,size_t len)92 ether_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
113 char *
ether_sprintf(const u_char * ap)114 ether_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
124 struct mbuf *
ether_vlanencap(struct mbuf * m,uint16_t tag)125 ether_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