1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Ethernet-type device handling.
7 *
8 * Version: @(#)eth.c 1.0.7 05/25/93
9 *
10 * Authors: Ross Biro
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 * Florian La Roche, <rzsfl@rz.uni-sb.de>
14 * Alan Cox, <gw4pts@gw4pts.ampr.org>
15 *
16 * Fixes:
17 * Mr Linux : Arp problems
18 * Alan Cox : Generic queue tidyup (very tiny here)
19 * Alan Cox : eth_header ntohs should be htons
20 * Alan Cox : eth_rebuild_header missing an htons and
21 * minor other things.
22 * Tegge : Arp bug fixes.
23 * Florian : Removed many unnecessary functions, code cleanup
24 * and changes for new arp and skbuff.
25 * Alan Cox : Redid header building to reflect new format.
26 * Alan Cox : ARP only when compiled with CONFIG_INET
27 * Greg Page : 802.2 and SNAP stuff.
28 * Alan Cox : MAC layer pointers/new format.
29 * Paul Gortmaker : eth_copy_and_sum shouldn't csum padding.
30 * Alan Cox : Protect against forwarding explosions with
31 * older network drivers and IFF_ALLMULTI.
32 * Christer Weinigel : Better rebuild header message.
33 * Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup().
34 *
35 * This program is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU General Public License
37 * as published by the Free Software Foundation; either version
38 * 2 of the License, or (at your option) any later version.
39 */
40 #include <linux/module.h>
41 #include <linux/types.h>
42 #include <linux/kernel.h>
43 #include <linux/string.h>
44 #include <linux/mm.h>
45 #include <linux/socket.h>
46 #include <linux/in.h>
47 #include <linux/inet.h>
48 #include <linux/ip.h>
49 #include <linux/netdevice.h>
50 #include <linux/etherdevice.h>
51 #include <linux/skbuff.h>
52 #include <linux/errno.h>
53 #include <linux/init.h>
54 #include <linux/if_ether.h>
55 #include <net/dst.h>
56 #include <net/arp.h>
57 #include <net/sock.h>
58 #include <net/ipv6.h>
59 #include <net/ip.h>
60 #include <net/dsa.h>
61 #include <asm/uaccess.h>
62 #include <asm/system.h>
63
64 __setup("ether=", netdev_boot_setup);
65
66 /**
67 * eth_header - create the Ethernet header
68 * @skb: buffer to alter
69 * @dev: source device
70 * @type: Ethernet type field
71 * @daddr: destination address (NULL leave destination address)
72 * @saddr: source address (NULL use device source address)
73 * @len: packet length (<= skb->len)
74 *
75 *
76 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
77 * in here instead. It is up to the 802.2 layer to carry protocol information.
78 */
79 int eth_header(struct sk_buff *skb, struct net_device *dev,
80 unsigned short type,
81 const void *daddr, const void *saddr, unsigned len)
82 {
83 struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
84
85 if (type != ETH_P_802_3)
86 eth->h_proto = htons(type);
87 else
88 eth->h_proto = htons(len);
89
90 /*
91 * Set the source hardware address.
92 */
93
94 if (!saddr)
95 saddr = dev->dev_addr;
96 memcpy(eth->h_source, saddr, ETH_ALEN);
97
98 if (daddr) {
99 memcpy(eth->h_dest, daddr, ETH_ALEN);
100 return ETH_HLEN;
101 }
102
103 /*
104 * Anyway, the loopback-device should never use this function...
105 */
106
107 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
108 memset(eth->h_dest, 0, ETH_ALEN);
109 return ETH_HLEN;
110 }
111
112 return -ETH_HLEN;
113 }
114 EXPORT_SYMBOL(eth_header);
115
116 /**
117 * eth_rebuild_header- rebuild the Ethernet MAC header.
118 * @skb: socket buffer to update
119 *
120 * This is called after an ARP or IPV6 ndisc it's resolution on this
121 * sk_buff. We now let protocol (ARP) fill in the other fields.
122 *
123 * This routine CANNOT use cached dst->neigh!
124 * Really, it is used only when dst->neigh is wrong.
125 */
126 int eth_rebuild_header(struct sk_buff *skb)
127 {
128 struct ethhdr *eth = (struct ethhdr *)skb->data;
129 struct net_device *dev = skb->dev;
130
131 switch (eth->h_proto) {
132 #ifdef CONFIG_INET
133 case htons(ETH_P_IP):
134 return arp_find(eth->h_dest, skb);
135 #endif
136 default:
137 printk(KERN_DEBUG
138 "%s: unable to resolve type %X addresses.\n",
139 dev->name, (int)eth->h_proto);
140
141 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
142 break;
143 }
144
145 return 0;
146 }
147 EXPORT_SYMBOL(eth_rebuild_header);
148
149 /**
150 * eth_type_trans - determine the packet's protocol ID.
151 * @skb: received socket data
152 * @dev: receiving network device
153 *
154 * The rule here is that we
155 * assume 802.3 if the type field is short enough to be a length.
156 * This is normal practice and works for any 'now in use' protocol.
157 */
158 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
159 {
160 struct ethhdr *eth;
161 unsigned char *rawp;
162
163 skb->dev = dev;
164 skb_reset_mac_header(skb);
165 skb_pull(skb, ETH_HLEN);
166 eth = eth_hdr(skb);
167
168 if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
169 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast))
170 skb->pkt_type = PACKET_BROADCAST;
171 else
172 skb->pkt_type = PACKET_MULTICAST;
173 }
174
175 /*
176 * This ALLMULTI check should be redundant by 1.4
177 * so don't forget to remove it.
178 *
179 * Seems, you forgot to remove it. All silly devices
180 * seems to set IFF_PROMISC.
181 */
182
183 else if (1 /*dev->flags&IFF_PROMISC */ ) {
184 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr)))
185 skb->pkt_type = PACKET_OTHERHOST;
186 }
187
188 /*
189 * Some variants of DSA tagging don't have an ethertype field
190 * at all, so we check here whether one of those tagging
191 * variants has been configured on the receiving interface,
192 * and if so, set skb->protocol without looking at the packet.
193 */
194 if (netdev_uses_dsa_tags(dev))
195 return htons(ETH_P_DSA);
196 if (netdev_uses_trailer_tags(dev))
197 return htons(ETH_P_TRAILER);
198
199 if (ntohs(eth->h_proto) >= 1536)
200 return eth->h_proto;
201
202 rawp = skb->data;
203
204 /*
205 * This is a magic hack to spot IPX packets. Older Novell breaks
206 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
207 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
208 * won't work for fault tolerant netware but does for the rest.
209 */
210 if (*(unsigned short *)rawp == 0xFFFF)
211 return htons(ETH_P_802_3);
212
213 /*
214 * Real 802.2 LLC
215 */
216 return htons(ETH_P_802_2);
217 }
218 EXPORT_SYMBOL(eth_type_trans);
219
220 /**
221 * eth_header_parse - extract hardware address from packet
222 * @skb: packet to extract header from
223 * @haddr: destination buffer
224 */
225 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
226 {
227 const struct ethhdr *eth = eth_hdr(skb);
228 memcpy(haddr, eth->h_source, ETH_ALEN);
229 return ETH_ALEN;
230 }
231 EXPORT_SYMBOL(eth_header_parse);
232
233 /**
234 * eth_header_cache - fill cache entry from neighbour
235 * @neigh: source neighbour
236 * @hh: destination cache entry
237 * Create an Ethernet header template from the neighbour.
238 */
239 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh)
240 {
241 __be16 type = hh->hh_type;
242 struct ethhdr *eth;
243 const struct net_device *dev = neigh->dev;
244
245 eth = (struct ethhdr *)
246 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
247
248 if (type == htons(ETH_P_802_3))
249 return -1;
250
251 eth->h_proto = type;
252 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
253 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
254 hh->hh_len = ETH_HLEN;
255 return 0;
256 }
257 EXPORT_SYMBOL(eth_header_cache);
258
259 /**
260 * eth_header_cache_update - update cache entry
261 * @hh: destination cache entry
262 * @dev: network device
263 * @haddr: new hardware address
264 *
265 * Called by Address Resolution module to notify changes in address.
266 */
267 void eth_header_cache_update(struct hh_cache *hh,
268 const struct net_device *dev,
269 const unsigned char *haddr)
270 {
271 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
272 haddr, ETH_ALEN);
273 }
274 EXPORT_SYMBOL(eth_header_cache_update);
275
276 /**
277 * eth_mac_addr - set new Ethernet hardware address
278 * @dev: network device
279 * @p: socket address
280 * Change hardware address of device.
281 *
282 * This doesn't change hardware matching, so needs to be overridden
283 * for most real devices.
284 */
285 int eth_mac_addr(struct net_device *dev, void *p)
286 {
287 struct sockaddr *addr = p;
288
289 if (netif_running(dev))
290 return -EBUSY;
291 if (!is_valid_ether_addr(addr->sa_data))
292 return -EADDRNOTAVAIL;
293 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
294 return 0;
295 }
296 EXPORT_SYMBOL(eth_mac_addr);
297
298 /**
299 * eth_change_mtu - set new MTU size
300 * @dev: network device
301 * @new_mtu: new Maximum Transfer Unit
302 *
303 * Allow changing MTU size. Needs to be overridden for devices
304 * supporting jumbo frames.
305 */
306 int eth_change_mtu(struct net_device *dev, int new_mtu)
307 {
308 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
309 return -EINVAL;
310 dev->mtu = new_mtu;
311 return 0;
312 }
313 EXPORT_SYMBOL(eth_change_mtu);
314
315 int eth_validate_addr(struct net_device *dev)
316 {
317 if (!is_valid_ether_addr(dev->dev_addr))
318 return -EADDRNOTAVAIL;
319
320 return 0;
321 }
322 EXPORT_SYMBOL(eth_validate_addr);
323
324 const struct header_ops eth_header_ops ____cacheline_aligned = {
325 .create = eth_header,
326 .parse = eth_header_parse,
327 .rebuild = eth_rebuild_header,
328 .cache = eth_header_cache,
329 .cache_update = eth_header_cache_update,
330 };
331
332 /**
333 * ether_setup - setup Ethernet network device
334 * @dev: network device
335 * Fill in the fields of the device structure with Ethernet-generic values.
336 */
337 void ether_setup(struct net_device *dev)
338 {
339 dev->header_ops = ð_header_ops;
340 dev->type = ARPHRD_ETHER;
341 dev->hard_header_len = ETH_HLEN;
342 dev->mtu = ETH_DATA_LEN;
343 dev->addr_len = ETH_ALEN;
344 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
345 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
346
347 memset(dev->broadcast, 0xFF, ETH_ALEN);
348
349 }
350 EXPORT_SYMBOL(ether_setup);
351
352 /**
353 * alloc_etherdev_mq - Allocates and sets up an Ethernet device
354 * @sizeof_priv: Size of additional driver-private structure to be allocated
355 * for this Ethernet device
356 * @queue_count: The number of queues this device has.
357 *
358 * Fill in the fields of the device structure with Ethernet-generic
359 * values. Basically does everything except registering the device.
360 *
361 * Constructs a new net device, complete with a private data area of
362 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
363 * this private data area.
364 */
365
366 struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count)
367 {
368 return alloc_netdev_mq(sizeof_priv, "eth%d", ether_setup, queue_count);
369 }
370 EXPORT_SYMBOL(alloc_etherdev_mq);
371
372 static size_t _format_mac_addr(char *buf, int buflen,
373 const unsigned char *addr, int len)
374 {
375 int i;
376 char *cp = buf;
377
378 for (i = 0; i < len; i++) {
379 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]);
380 if (i == len - 1)
381 break;
382 cp += strlcpy(cp, ":", buflen - (cp - buf));
383 }
384 return cp - buf;
385 }
386
387 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
388 {
389 size_t l;
390
391 l = _format_mac_addr(buf, PAGE_SIZE, addr, len);
392 l += strlcpy(buf + l, "\n", PAGE_SIZE - l);
393 return ((ssize_t) l);
394 }
395 EXPORT_SYMBOL(sysfs_format_mac);
396
397 char *print_mac(char *buf, const unsigned char *addr)
398 {
399 _format_mac_addr(buf, MAC_BUF_SIZE, addr, ETH_ALEN);
400 return buf;
401 }
402 EXPORT_SYMBOL(print_mac);
403
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