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_3/2 we put the length
77 * in here instead.
78 */
eth_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,const void * daddr,const void * saddr,unsigned len)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 && type != ETH_P_802_2)
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 */
eth_rebuild_header(struct sk_buff * skb)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, ntohs(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 */
eth_type_trans(struct sk_buff * skb,struct net_device * dev)158 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
159 {
160 struct ethhdr *eth;
161
162 skb->dev = dev;
163 skb_reset_mac_header(skb);
164 skb_pull_inline(skb, ETH_HLEN);
165 eth = eth_hdr(skb);
166
167 if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
168 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast))
169 skb->pkt_type = PACKET_BROADCAST;
170 else
171 skb->pkt_type = PACKET_MULTICAST;
172 }
173
174 /*
175 * This ALLMULTI check should be redundant by 1.4
176 * so don't forget to remove it.
177 *
178 * Seems, you forgot to remove it. All silly devices
179 * seems to set IFF_PROMISC.
180 */
181
182 else if (1 /*dev->flags&IFF_PROMISC */ ) {
183 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr)))
184 skb->pkt_type = PACKET_OTHERHOST;
185 }
186
187 /*
188 * Some variants of DSA tagging don't have an ethertype field
189 * at all, so we check here whether one of those tagging
190 * variants has been configured on the receiving interface,
191 * and if so, set skb->protocol without looking at the packet.
192 */
193 if (netdev_uses_dsa_tags(dev))
194 return htons(ETH_P_DSA);
195 if (netdev_uses_trailer_tags(dev))
196 return htons(ETH_P_TRAILER);
197
198 if (ntohs(eth->h_proto) >= 1536)
199 return eth->h_proto;
200
201 /*
202 * This is a magic hack to spot IPX packets. Older Novell breaks
203 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
204 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
205 * won't work for fault tolerant netware but does for the rest.
206 */
207 if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF)
208 return htons(ETH_P_802_3);
209
210 /*
211 * Real 802.2 LLC
212 */
213 return htons(ETH_P_802_2);
214 }
215 EXPORT_SYMBOL(eth_type_trans);
216
217 /**
218 * eth_header_parse - extract hardware address from packet
219 * @skb: packet to extract header from
220 * @haddr: destination buffer
221 */
eth_header_parse(const struct sk_buff * skb,unsigned char * haddr)222 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
223 {
224 const struct ethhdr *eth = eth_hdr(skb);
225 memcpy(haddr, eth->h_source, ETH_ALEN);
226 return ETH_ALEN;
227 }
228 EXPORT_SYMBOL(eth_header_parse);
229
230 /**
231 * eth_header_cache - fill cache entry from neighbour
232 * @neigh: source neighbour
233 * @hh: destination cache entry
234 * Create an Ethernet header template from the neighbour.
235 */
eth_header_cache(const struct neighbour * neigh,struct hh_cache * hh)236 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh)
237 {
238 __be16 type = hh->hh_type;
239 struct ethhdr *eth;
240 const struct net_device *dev = neigh->dev;
241
242 eth = (struct ethhdr *)
243 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
244
245 if (type == htons(ETH_P_802_3))
246 return -1;
247
248 eth->h_proto = type;
249 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
250 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
251 hh->hh_len = ETH_HLEN;
252 return 0;
253 }
254 EXPORT_SYMBOL(eth_header_cache);
255
256 /**
257 * eth_header_cache_update - update cache entry
258 * @hh: destination cache entry
259 * @dev: network device
260 * @haddr: new hardware address
261 *
262 * Called by Address Resolution module to notify changes in address.
263 */
eth_header_cache_update(struct hh_cache * hh,const struct net_device * dev,const unsigned char * haddr)264 void eth_header_cache_update(struct hh_cache *hh,
265 const struct net_device *dev,
266 const unsigned char *haddr)
267 {
268 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
269 haddr, ETH_ALEN);
270 }
271 EXPORT_SYMBOL(eth_header_cache_update);
272
273 /**
274 * eth_mac_addr - set new Ethernet hardware address
275 * @dev: network device
276 * @p: socket address
277 * Change hardware address of device.
278 *
279 * This doesn't change hardware matching, so needs to be overridden
280 * for most real devices.
281 */
eth_mac_addr(struct net_device * dev,void * p)282 int eth_mac_addr(struct net_device *dev, void *p)
283 {
284 struct sockaddr *addr = p;
285
286 if (netif_running(dev))
287 return -EBUSY;
288 if (!is_valid_ether_addr(addr->sa_data))
289 return -EADDRNOTAVAIL;
290 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
291 return 0;
292 }
293 EXPORT_SYMBOL(eth_mac_addr);
294
295 /**
296 * eth_change_mtu - set new MTU size
297 * @dev: network device
298 * @new_mtu: new Maximum Transfer Unit
299 *
300 * Allow changing MTU size. Needs to be overridden for devices
301 * supporting jumbo frames.
302 */
eth_change_mtu(struct net_device * dev,int new_mtu)303 int eth_change_mtu(struct net_device *dev, int new_mtu)
304 {
305 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
306 return -EINVAL;
307 dev->mtu = new_mtu;
308 return 0;
309 }
310 EXPORT_SYMBOL(eth_change_mtu);
311
eth_validate_addr(struct net_device * dev)312 int eth_validate_addr(struct net_device *dev)
313 {
314 if (!is_valid_ether_addr(dev->dev_addr))
315 return -EADDRNOTAVAIL;
316
317 return 0;
318 }
319 EXPORT_SYMBOL(eth_validate_addr);
320
321 const struct header_ops eth_header_ops ____cacheline_aligned = {
322 .create = eth_header,
323 .parse = eth_header_parse,
324 .rebuild = eth_rebuild_header,
325 .cache = eth_header_cache,
326 .cache_update = eth_header_cache_update,
327 };
328
329 /**
330 * ether_setup - setup Ethernet network device
331 * @dev: network device
332 * Fill in the fields of the device structure with Ethernet-generic values.
333 */
ether_setup(struct net_device * dev)334 void ether_setup(struct net_device *dev)
335 {
336 dev->header_ops = ð_header_ops;
337 dev->type = ARPHRD_ETHER;
338 dev->hard_header_len = ETH_HLEN;
339 dev->mtu = ETH_DATA_LEN;
340 dev->addr_len = ETH_ALEN;
341 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
342 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
343
344 memset(dev->broadcast, 0xFF, ETH_ALEN);
345
346 }
347 EXPORT_SYMBOL(ether_setup);
348
349 /**
350 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
351 * @sizeof_priv: Size of additional driver-private structure to be allocated
352 * for this Ethernet device
353 * @txqs: The number of TX queues this device has.
354 * @rxqs: The number of RX queues this device has.
355 *
356 * Fill in the fields of the device structure with Ethernet-generic
357 * values. Basically does everything except registering the device.
358 *
359 * Constructs a new net device, complete with a private data area of
360 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
361 * this private data area.
362 */
363
alloc_etherdev_mqs(int sizeof_priv,unsigned int txqs,unsigned int rxqs)364 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
365 unsigned int rxqs)
366 {
367 return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
368 }
369 EXPORT_SYMBOL(alloc_etherdev_mqs);
370
_format_mac_addr(char * buf,int buflen,const unsigned char * addr,int len)371 static size_t _format_mac_addr(char *buf, int buflen,
372 const unsigned char *addr, int len)
373 {
374 int i;
375 char *cp = buf;
376
377 for (i = 0; i < len; i++) {
378 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]);
379 if (i == len - 1)
380 break;
381 cp += scnprintf(cp, buflen - (cp - buf), ":");
382 }
383 return cp - buf;
384 }
385
sysfs_format_mac(char * buf,const unsigned char * addr,int len)386 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
387 {
388 size_t l;
389
390 l = _format_mac_addr(buf, PAGE_SIZE, addr, len);
391 l += scnprintf(buf + l, PAGE_SIZE - l, "\n");
392 return (ssize_t)l;
393 }
394 EXPORT_SYMBOL(sysfs_format_mac);
395