summaryrefslogtreecommitdiff
path: root/net/ethernet/eth.c
blob: f777e17d28c8772572ed5cbf536d25e35558bad4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Ethernet-type device handling.
 *
 * Version:	@(#)eth.c	1.0.7	05/25/93
 *
 * Authors:	Ross Biro
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Mark Evans, <evansmp@uhura.aston.ac.uk>
 *		Florian  La Roche, <rzsfl@rz.uni-sb.de>
 *		Alan Cox, <gw4pts@gw4pts.ampr.org>
 *
 * Fixes:
 *		Mr Linux	: Arp problems
 *		Alan Cox	: Generic queue tidyup (very tiny here)
 *		Alan Cox	: eth_header ntohs should be htons
 *		Alan Cox	: eth_rebuild_header missing an htons and
 *				  minor other things.
 *		Tegge		: Arp bug fixes.
 *		Florian		: Removed many unnecessary functions, code cleanup
 *				  and changes for new arp and skbuff.
 *		Alan Cox	: Redid header building to reflect new format.
 *		Alan Cox	: ARP only when compiled with CONFIG_INET
 *		Greg Page	: 802.2 and SNAP stuff.
 *		Alan Cox	: MAC layer pointers/new format.
 *		Paul Gortmaker	: eth_copy_and_sum shouldn't csum padding.
 *		Alan Cox	: Protect against forwarding explosions with
 *				  older network drivers and IFF_ALLMULTI.
 *	Christer Weinigel	: Better rebuild header message.
 *             Andrew Morton    : 26Feb01: kill ether_setup() - use netdev_boot_setup().
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/ip.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/if_ether.h>
#include <net/dst.h>
#include <net/arp.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip.h>
#include <net/dsa.h>
#include <linux/uaccess.h>

__setup("ether=", netdev_boot_setup);

/**
 * eth_header - create the Ethernet header
 * @skb:	buffer to alter
 * @dev:	source device
 * @type:	Ethernet type field
 * @daddr: destination address (NULL leave destination address)
 * @saddr: source address (NULL use device source address)
 * @len:   packet length (<= skb->len)
 *
 *
 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
 * in here instead.
 */
int eth_header(struct sk_buff *skb, struct net_device *dev,
	       unsigned short type,
	       const void *daddr, const void *saddr, unsigned int len)
{
	struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);

	if (type != ETH_P_802_3 && type != ETH_P_802_2)
		eth->h_proto = htons(type);
	else
		eth->h_proto = htons(len);

	/*
	 *      Set the source hardware address.
	 */

	if (!saddr)
		saddr = dev->dev_addr;
	memcpy(eth->h_source, saddr, ETH_ALEN);

	if (daddr) {
		memcpy(eth->h_dest, daddr, ETH_ALEN);
		return ETH_HLEN;
	}

	/*
	 *      Anyway, the loopback-device should never use this function...
	 */

	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
		memset(eth->h_dest, 0, ETH_ALEN);
		return ETH_HLEN;
	}

	return -ETH_HLEN;
}
EXPORT_SYMBOL(eth_header);

/**
 * eth_rebuild_header- rebuild the Ethernet MAC header.
 * @skb: socket buffer to update
 *
 * This is called after an ARP or IPV6 ndisc it's resolution on this
 * sk_buff. We now let protocol (ARP) fill in the other fields.
 *
 * This routine CANNOT use cached dst->neigh!
 * Really, it is used only when dst->neigh is wrong.
 */
int eth_rebuild_header(struct sk_buff *skb)
{
	struct ethhdr *eth = (struct ethhdr *)skb->data;
	struct net_device *dev = skb->dev;

	switch (eth->h_proto) {
#ifdef CONFIG_INET
	case htons(ETH_P_IP):
		return arp_find(eth->h_dest, skb);
#endif
	default:
		netdev_dbg(dev,
		       "%s: unable to resolve type %X addresses.\n",
		       dev->name, ntohs(eth->h_proto));

		memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
		break;
	}

	return 0;
}
EXPORT_SYMBOL(eth_rebuild_header);

/**
 * eth_type_trans - determine the packet's protocol ID.
 * @skb: received socket data
 * @dev: receiving network device
 *
 * The rule here is that we
 * assume 802.3 if the type field is short enough to be a length.
 * This is normal practice and works for any 'now in use' protocol.
 */
__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
{
	struct ethhdr *eth;

	skb->dev = dev;
	skb_reset_mac_header(skb);
	skb_pull_inline(skb, ETH_HLEN);
	eth = eth_hdr(skb);

	if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
		if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
			skb->pkt_type = PACKET_BROADCAST;
		else
			skb->pkt_type = PACKET_MULTICAST;
	}
	else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
						   dev->dev_addr)))
		skb->pkt_type = PACKET_OTHERHOST;

	/*
	 * Some variants of DSA tagging don't have an ethertype field
	 * at all, so we check here whether one of those tagging
	 * variants has been configured on the receiving interface,
	 * and if so, set skb->protocol without looking at the packet.
	 */
	if (netdev_uses_dsa_tags(dev))
		return htons(ETH_P_DSA);
	if (netdev_uses_trailer_tags(dev))
		return htons(ETH_P_TRAILER);

	if (ntohs(eth->h_proto) >= ETH_P_802_3_MIN)
		return eth->h_proto;

	/*
	 *      This is a magic hack to spot IPX packets. Older Novell breaks
	 *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
	 *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
	 *      won't work for fault tolerant netware but does for the rest.
	 */
	if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF)
		return htons(ETH_P_802_3);

	/*
	 *      Real 802.2 LLC
	 */
	return htons(ETH_P_802_2);
}
EXPORT_SYMBOL(eth_type_trans);

/**
 * eth_header_parse - extract hardware address from packet
 * @skb: packet to extract header from
 * @haddr: destination buffer
 */
int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
{
	const struct ethhdr *eth = eth_hdr(skb);
	memcpy(haddr, eth->h_source, ETH_ALEN);
	return ETH_ALEN;
}
EXPORT_SYMBOL(eth_header_parse);

/**
 * eth_header_cache - fill cache entry from neighbour
 * @neigh: source neighbour
 * @hh: destination cache entry
 * @type: Ethernet type field
 *
 * Create an Ethernet header template from the neighbour.
 */
int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
{
	struct ethhdr *eth;
	const struct net_device *dev = neigh->dev;

	eth = (struct ethhdr *)
	    (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));

	if (type == htons(ETH_P_802_3))
		return -1;

	eth->h_proto = type;
	memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
	memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
	hh->hh_len = ETH_HLEN;
	return 0;
}
EXPORT_SYMBOL(eth_header_cache);

/**
 * eth_header_cache_update - update cache entry
 * @hh: destination cache entry
 * @dev: network device
 * @haddr: new hardware address
 *
 * Called by Address Resolution module to notify changes in address.
 */
void eth_header_cache_update(struct hh_cache *hh,
			     const struct net_device *dev,
			     const unsigned char *haddr)
{
	memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
	       haddr, ETH_ALEN);
}
EXPORT_SYMBOL(eth_header_cache_update);

/**
 * eth_prepare_mac_addr_change - prepare for mac change
 * @dev: network device
 * @p: socket address
 */
int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
{
	struct sockaddr *addr = p;

	if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
		return -EBUSY;
	if (!is_valid_ether_addr(addr->sa_data))
		return -EADDRNOTAVAIL;
	return 0;
}
EXPORT_SYMBOL(eth_prepare_mac_addr_change);

/**
 * eth_commit_mac_addr_change - commit mac change
 * @dev: network device
 * @p: socket address
 */
void eth_commit_mac_addr_change(struct net_device *dev, void *p)
{
	struct sockaddr *addr = p;

	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
}
EXPORT_SYMBOL(eth_commit_mac_addr_change);

/**
 * eth_mac_addr - set new Ethernet hardware address
 * @dev: network device
 * @p: socket address
 *
 * Change hardware address of device.
 *
 * This doesn't change hardware matching, so needs to be overridden
 * for most real devices.
 */
int eth_mac_addr(struct net_device *dev, void *p)
{
	int ret;

	ret = eth_prepare_mac_addr_change(dev, p);
	if (ret < 0)
		return ret;
	eth_commit_mac_addr_change(dev, p);
	return 0;
}
EXPORT_SYMBOL(eth_mac_addr);

/**
 * eth_change_mtu - set new MTU size
 * @dev: network device
 * @new_mtu: new Maximum Transfer Unit
 *
 * Allow changing MTU size. Needs to be overridden for devices
 * supporting jumbo frames.
 */
int eth_change_mtu(struct net_device *dev, int new_mtu)
{
	if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}
EXPORT_SYMBOL(eth_change_mtu);

int eth_validate_addr(struct net_device *dev)
{
	if (!is_valid_ether_addr(dev->dev_addr))
		return -EADDRNOTAVAIL;

	return 0;
}
EXPORT_SYMBOL(eth_validate_addr);

const struct header_ops eth_header_ops ____cacheline_aligned = {
	.create		= eth_header,
	.parse		= eth_header_parse,
	.rebuild	= eth_rebuild_header,
	.cache		= eth_header_cache,
	.cache_update	= eth_header_cache_update,
};

/**
 * ether_setup - setup Ethernet network device
 * @dev: network device
 *
 * Fill in the fields of the device structure with Ethernet-generic values.
 */
void ether_setup(struct net_device *dev)
{
	dev->header_ops		= &eth_header_ops;
	dev->type		= ARPHRD_ETHER;
	dev->hard_header_len 	= ETH_HLEN;
	dev->mtu		= ETH_DATA_LEN;
	dev->addr_len		= ETH_ALEN;
	dev->tx_queue_len	= 1000;	/* Ethernet wants good queues */
	dev->flags		= IFF_BROADCAST|IFF_MULTICAST;
	dev->priv_flags		|= IFF_TX_SKB_SHARING;

	memset(dev->broadcast, 0xFF, ETH_ALEN);

}
EXPORT_SYMBOL(ether_setup);

/**
 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
 * @sizeof_priv: Size of additional driver-private structure to be allocated
 *	for this Ethernet device
 * @txqs: The number of TX queues this device has.
 * @rxqs: The number of RX queues this device has.
 *
 * Fill in the fields of the device structure with Ethernet-generic
 * values. Basically does everything except registering the device.
 *
 * Constructs a new net device, complete with a private data area of
 * size (sizeof_priv).  A 32-byte (not bit) alignment is enforced for
 * this private data area.
 */

struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
				      unsigned int rxqs)
{
	return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
}
EXPORT_SYMBOL(alloc_etherdev_mqs);

ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
{
	return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
}
EXPORT_SYMBOL(sysfs_format_mac);