1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. NET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Definitions for the Ethernet handlers.
7 *
8 * Version: @(#)eth.h 1.0.4 05/13/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * Relocated to include/linux where it belongs by Alan Cox
14 * <gw4pts@gw4pts.ampr.org>
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
20 *
21 * WARNING: This move may well be temporary. This file will get merged with others RSN.
22 *
23 */
24 #ifndef _LINUX_ETHERDEVICE_H
25 #define _LINUX_ETHERDEVICE_H
26
27 #include <linux/if_ether.h>
28 #include <linux/netdevice.h>
29 #include <linux/random.h>
30 #include <asm/unaligned.h>
31
32 #ifdef __KERNEL__
33 extern __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
34 extern const struct header_ops eth_header_ops;
35
36 extern int eth_header(struct sk_buff *skb, struct net_device *dev,
37 unsigned short type,
38 const void *daddr, const void *saddr, unsigned len);
39 extern int eth_rebuild_header(struct sk_buff *skb);
40 extern int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
41 extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh);
42 extern void eth_header_cache_update(struct hh_cache *hh,
43 const struct net_device *dev,
44 const unsigned char *haddr);
45 extern int eth_mac_addr(struct net_device *dev, void *p);
46 extern int eth_change_mtu(struct net_device *dev, int new_mtu);
47 extern int eth_validate_addr(struct net_device *dev);
48
49
50
51 extern struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count);
52 #define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
53
54 /**
55 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
56 * @addr: Pointer to a six-byte array containing the Ethernet address
57 *
58 * Return true if the address is all zeroes.
59 */
60 static inline int is_zero_ether_addr(const u8 *addr)
61 {
62 return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
63 }
64
65 /**
66 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
67 * @addr: Pointer to a six-byte array containing the Ethernet address
68 *
69 * Return true if the address is a multicast address.
70 * By definition the broadcast address is also a multicast address.
71 */
72 static inline int is_multicast_ether_addr(const u8 *addr)
73 {
74 return (0x01 & addr[0]);
75 }
76
77 /**
78 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
79 * @addr: Pointer to a six-byte array containing the Ethernet address
80 *
81 * Return true if the address is a local address.
82 */
83 static inline int is_local_ether_addr(const u8 *addr)
84 {
85 return (0x02 & addr[0]);
86 }
87
88 /**
89 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
90 * @addr: Pointer to a six-byte array containing the Ethernet address
91 *
92 * Return true if the address is the broadcast address.
93 */
94 static inline int is_broadcast_ether_addr(const u8 *addr)
95 {
96 return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
97 }
98
99 /**
100 * is_valid_ether_addr - Determine if the given Ethernet address is valid
101 * @addr: Pointer to a six-byte array containing the Ethernet address
102 *
103 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
104 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
105 *
106 * Return true if the address is valid.
107 */
108 static inline int is_valid_ether_addr(const u8 *addr)
109 {
110 /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
111 * explicitly check for it here. */
112 return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
113 }
114
115 /**
116 * random_ether_addr - Generate software assigned random Ethernet address
117 * @addr: Pointer to a six-byte array containing the Ethernet address
118 *
119 * Generate a random Ethernet address (MAC) that is not multicast
120 * and has the local assigned bit set.
121 */
122 static inline void random_ether_addr(u8 *addr)
123 {
124 get_random_bytes (addr, ETH_ALEN);
125 addr [0] &= 0xfe; /* clear multicast bit */
126 addr [0] |= 0x02; /* set local assignment bit (IEEE802) */
127 }
128
129 /**
130 * compare_ether_addr - Compare two Ethernet addresses
131 * @addr1: Pointer to a six-byte array containing the Ethernet address
132 * @addr2: Pointer other six-byte array containing the Ethernet address
133 *
134 * Compare two ethernet addresses, returns 0 if equal
135 */
136 static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
137 {
138 const u16 *a = (const u16 *) addr1;
139 const u16 *b = (const u16 *) addr2;
140
141 BUILD_BUG_ON(ETH_ALEN != 6);
142 return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
143 }
144
145 static inline unsigned long zap_last_2bytes(unsigned long value)
146 {
147 #ifdef __BIG_ENDIAN
148 return value >> 16;
149 #else
150 return value << 16;
151 #endif
152 }
153
154 /**
155 * compare_ether_addr_64bits - Compare two Ethernet addresses
156 * @addr1: Pointer to an array of 8 bytes
157 * @addr2: Pointer to an other array of 8 bytes
158 *
159 * Compare two ethernet addresses, returns 0 if equal.
160 * Same result than "memcmp(addr1, addr2, ETH_ALEN)" but without conditional
161 * branches, and possibly long word memory accesses on CPU allowing cheap
162 * unaligned memory reads.
163 * arrays = { byte1, byte2, byte3, byte4, byte6, byte7, pad1, pad2}
164 *
165 * Please note that alignment of addr1 & addr2 is only guaranted to be 16 bits.
166 */
167
168 static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2],
169 const u8 addr2[6+2])
170 {
171 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
172 unsigned long fold = ((*(unsigned long *)addr1) ^
173 (*(unsigned long *)addr2));
174
175 if (sizeof(fold) == 8)
176 return zap_last_2bytes(fold) != 0;
177
178 fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
179 (*(unsigned long *)(addr2 + 4)));
180 return fold != 0;
181 #else
182 return compare_ether_addr(addr1, addr2);
183 #endif
184 }
185
186 /**
187 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
188 * @dev: Pointer to a device structure
189 * @addr: Pointer to a six-byte array containing the Ethernet address
190 *
191 * Compare passed address with all addresses of the device. Return true if the
192 * address if one of the device addresses.
193 *
194 * Note that this function calls compare_ether_addr_64bits() so take care of
195 * the right padding.
196 */
197 static inline bool is_etherdev_addr(const struct net_device *dev,
198 const u8 addr[6 + 2])
199 {
200 struct netdev_hw_addr *ha;
201 int res = 1;
202
203 rcu_read_lock();
204 for_each_dev_addr(dev, ha) {
205 res = compare_ether_addr_64bits(addr, ha->addr);
206 if (!res)
207 break;
208 }
209 rcu_read_unlock();
210 return !res;
211 }
212 #endif /* __KERNEL__ */
213
214 /**
215 * compare_ether_header - Compare two Ethernet headers
216 * @a: Pointer to Ethernet header
217 * @b: Pointer to Ethernet header
218 *
219 * Compare two ethernet headers, returns 0 if equal.
220 * This assumes that the network header (i.e., IP header) is 4-byte
221 * aligned OR the platform can handle unaligned access. This is the
222 * case for all packets coming into netif_receive_skb or similar
223 * entry points.
224 */
225
226 static inline int compare_ether_header(const void *a, const void *b)
227 {
228 u32 *a32 = (u32 *)((u8 *)a + 2);
229 u32 *b32 = (u32 *)((u8 *)b + 2);
230
231 return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
232 (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
233 }
234
235 #endif /* _LINUX_ETHERDEVICE_H */
236
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