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
63 __setup("ether=", netdev_boot_setup);
64
65 /**
66 * eth_header - create the Ethernet header
67 * @skb: buffer to alter
68 * @dev: source device
69 * @type: Ethernet type field
70 * @daddr: destination address (NULL leave destination address)
71 * @saddr: source address (NULL use device source address)
72 * @len: packet length (<= skb->len)
73 *
74 *
75 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
76 * in here instead.
77 */
eth_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,const void * daddr,const void * saddr,unsigned len)78 int eth_header(struct sk_buff *skb, struct net_device *dev,
79 unsigned short type,
80 const void *daddr, const void *saddr, unsigned len)
81 {
82 struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
83
84 if (type != ETH_P_802_3 && type != ETH_P_802_2)
85 eth->h_proto = htons(type);
86 else
87 eth->h_proto = htons(len);
88
89 /*
90 * Set the source hardware address.
91 */
92
93 if (!saddr)
94 saddr = dev->dev_addr;
95 memcpy(eth->h_source, saddr, ETH_ALEN);
96
97 if (daddr) {
98 memcpy(eth->h_dest, daddr, ETH_ALEN);
99 return ETH_HLEN;
100 }
101
102 /*
103 * Anyway, the loopback-device should never use this function...
104 */
105
106 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
107 memset(eth->h_dest, 0, ETH_ALEN);
108 return ETH_HLEN;
109 }
110
111 return -ETH_HLEN;
112 }
113 EXPORT_SYMBOL(eth_header);
114
115 /**
116 * eth_rebuild_header- rebuild the Ethernet MAC header.
117 * @skb: socket buffer to update
118 *
119 * This is called after an ARP or IPV6 ndisc it's resolution on this
120 * sk_buff. We now let protocol (ARP) fill in the other fields.
121 *
122 * This routine CANNOT use cached dst->neigh!
123 * Really, it is used only when dst->neigh is wrong.
124 */
eth_rebuild_header(struct sk_buff * skb)125 int eth_rebuild_header(struct sk_buff *skb)
126 {
127 struct ethhdr *eth = (struct ethhdr *)skb->data;
128 struct net_device *dev = skb->dev;
129
130 switch (eth->h_proto) {
131 #ifdef CONFIG_INET
132 case htons(ETH_P_IP):
133 return arp_find(eth->h_dest, skb);
134 #endif
135 default:
136 printk(KERN_DEBUG
137 "%s: unable to resolve type %X addresses.\n",
138 dev->name, ntohs(eth->h_proto));
139
140 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
141 break;
142 }
143
144 return 0;
145 }
146 EXPORT_SYMBOL(eth_rebuild_header);
147
148 /**
149 * eth_type_trans - determine the packet's protocol ID.
150 * @skb: received socket data
151 * @dev: receiving network device
152 *
153 * The rule here is that we
154 * assume 802.3 if the type field is short enough to be a length.
155 * This is normal practice and works for any 'now in use' protocol.
156 */
eth_type_trans(struct sk_buff * skb,struct net_device * dev)157 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
158 {
159 struct ethhdr *eth;
160
161 skb->dev = dev;
162 skb_reset_mac_header(skb);
163 skb_pull_inline(skb, ETH_HLEN);
164 eth = eth_hdr(skb);
165
166 if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
167 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast))
168 skb->pkt_type = PACKET_BROADCAST;
169 else
170 skb->pkt_type = PACKET_MULTICAST;
171 }
172
173 /*
174 * This ALLMULTI check should be redundant by 1.4
175 * so don't forget to remove it.
176 *
177 * Seems, you forgot to remove it. All silly devices
178 * seems to set IFF_PROMISC.
179 */
180
181 else if (1 /*dev->flags&IFF_PROMISC */ ) {
182 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr)))
183 skb->pkt_type = PACKET_OTHERHOST;
184 }
185
186 /*
187 * Some variants of DSA tagging don't have an ethertype field
188 * at all, so we check here whether one of those tagging
189 * variants has been configured on the receiving interface,
190 * and if so, set skb->protocol without looking at the packet.
191 */
192 if (netdev_uses_dsa_tags(dev))
193 return htons(ETH_P_DSA);
194 if (netdev_uses_trailer_tags(dev))
195 return htons(ETH_P_TRAILER);
196
197 if (ntohs(eth->h_proto) >= 1536)
198 return eth->h_proto;
199
200 /*
201 * This is a magic hack to spot IPX packets. Older Novell breaks
202 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
203 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
204 * won't work for fault tolerant netware but does for the rest.
205 */
206 if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF)
207 return htons(ETH_P_802_3);
208
209 /*
210 * Real 802.2 LLC
211 */
212 return htons(ETH_P_802_2);
213 }
214 EXPORT_SYMBOL(eth_type_trans);
215
216 /**
217 * eth_header_parse - extract hardware address from packet
218 * @skb: packet to extract header from
219 * @haddr: destination buffer
220 */
eth_header_parse(const struct sk_buff * skb,unsigned char * haddr)221 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
222 {
223 const struct ethhdr *eth = eth_hdr(skb);
224 memcpy(haddr, eth->h_source, ETH_ALEN);
225 return ETH_ALEN;
226 }
227 EXPORT_SYMBOL(eth_header_parse);
228
229 /**
230 * eth_header_cache - fill cache entry from neighbour
231 * @neigh: source neighbour
232 * @hh: destination cache entry
233 * @type: Ethernet type field
234 * Create an Ethernet header template from the neighbour.
235 */
eth_header_cache(const struct neighbour * neigh,struct hh_cache * hh,__be16 type)236 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
237 {
238 struct ethhdr *eth;
239 const struct net_device *dev = neigh->dev;
240
241 eth = (struct ethhdr *)
242 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
243
244 if (type == htons(ETH_P_802_3))
245 return -1;
246
247 eth->h_proto = type;
248 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
249 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
250 hh->hh_len = ETH_HLEN;
251 return 0;
252 }
253 EXPORT_SYMBOL(eth_header_cache);
254
255 /**
256 * eth_header_cache_update - update cache entry
257 * @hh: destination cache entry
258 * @dev: network device
259 * @haddr: new hardware address
260 *
261 * Called by Address Resolution module to notify changes in address.
262 */
eth_header_cache_update(struct hh_cache * hh,const struct net_device * dev,const unsigned char * haddr)263 void eth_header_cache_update(struct hh_cache *hh,
264 const struct net_device *dev,
265 const unsigned char *haddr)
266 {
267 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
268 haddr, ETH_ALEN);
269 }
270 EXPORT_SYMBOL(eth_header_cache_update);
271
272 /**
273 * eth_mac_addr - set new Ethernet hardware address
274 * @dev: network device
275 * @p: socket address
276 * Change hardware address of device.
277 *
278 * This doesn't change hardware matching, so needs to be overridden
279 * for most real devices.
280 */
eth_mac_addr(struct net_device * dev,void * p)281 int eth_mac_addr(struct net_device *dev, void *p)
282 {
283 struct sockaddr *addr = p;
284
285 if (netif_running(dev))
286 return -EBUSY;
287 if (!is_valid_ether_addr(addr->sa_data))
288 return -EADDRNOTAVAIL;
289 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
290 /* if device marked as NET_ADDR_RANDOM, reset it */
291 dev->addr_assign_type &= ~NET_ADDR_RANDOM;
292 return 0;
293 }
294 EXPORT_SYMBOL(eth_mac_addr);
295
296 /**
297 * eth_change_mtu - set new MTU size
298 * @dev: network device
299 * @new_mtu: new Maximum Transfer Unit
300 *
301 * Allow changing MTU size. Needs to be overridden for devices
302 * supporting jumbo frames.
303 */
eth_change_mtu(struct net_device * dev,int new_mtu)304 int eth_change_mtu(struct net_device *dev, int new_mtu)
305 {
306 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
307 return -EINVAL;
308 dev->mtu = new_mtu;
309 return 0;
310 }
311 EXPORT_SYMBOL(eth_change_mtu);
312
eth_validate_addr(struct net_device * dev)313 int eth_validate_addr(struct net_device *dev)
314 {
315 if (!is_valid_ether_addr(dev->dev_addr))
316 return -EADDRNOTAVAIL;
317
318 return 0;
319 }
320 EXPORT_SYMBOL(eth_validate_addr);
321
322 const struct header_ops eth_header_ops ____cacheline_aligned = {
323 .create = eth_header,
324 .parse = eth_header_parse,
325 .rebuild = eth_rebuild_header,
326 .cache = eth_header_cache,
327 .cache_update = eth_header_cache_update,
328 };
329
330 /**
331 * ether_setup - setup Ethernet network device
332 * @dev: network device
333 * Fill in the fields of the device structure with Ethernet-generic values.
334 */
ether_setup(struct net_device * dev)335 void ether_setup(struct net_device *dev)
336 {
337 dev->header_ops = ð_header_ops;
338 dev->type = ARPHRD_ETHER;
339 dev->hard_header_len = ETH_HLEN;
340 dev->mtu = ETH_DATA_LEN;
341 dev->addr_len = ETH_ALEN;
342 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
343 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
344 dev->priv_flags |= IFF_TX_SKB_SHARING;
345
346 memset(dev->broadcast, 0xFF, ETH_ALEN);
347
348 }
349 EXPORT_SYMBOL(ether_setup);
350
351 /**
352 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
353 * @sizeof_priv: Size of additional driver-private structure to be allocated
354 * for this Ethernet device
355 * @txqs: The number of TX queues this device has.
356 * @rxqs: The number of RX 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
alloc_etherdev_mqs(int sizeof_priv,unsigned int txqs,unsigned int rxqs)366 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
367 unsigned int rxqs)
368 {
369 return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs);
370 }
371 EXPORT_SYMBOL(alloc_etherdev_mqs);
372
_format_mac_addr(char * buf,int buflen,const unsigned char * addr,int len)373 static size_t _format_mac_addr(char *buf, int buflen,
374 const unsigned char *addr, int len)
375 {
376 int i;
377 char *cp = buf;
378
379 for (i = 0; i < len; i++) {
380 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]);
381 if (i == len - 1)
382 break;
383 cp += scnprintf(cp, buflen - (cp - buf), ":");
384 }
385 return cp - buf;
386 }
387
sysfs_format_mac(char * buf,const unsigned char * addr,int len)388 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
389 {
390 size_t l;
391
392 l = _format_mac_addr(buf, PAGE_SIZE, addr, len);
393 l += scnprintf(buf + l, PAGE_SIZE - l, "\n");
394 return (ssize_t)l;
395 }
396 EXPORT_SYMBOL(sysfs_format_mac);
397