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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 *
Jesper Juhl02c30a82005-05-05 16:16:16 -070010 * Authors: Ross Biro
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * 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>
YOSHIFUJI Hideaki03d52d72007-02-09 23:24:44 +090015 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070016 * 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.
YOSHIFUJI Hideaki03d52d72007-02-09 23:24:44 +090022 * Tegge : Arp bug fixes.
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 * 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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <linux/init.h>
Kris Katterjohn46f25df2006-01-05 16:35:42 -080054#include <linux/if_ether.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055#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 <asm/uaccess.h>
61#include <asm/system.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063__setup("ether=", netdev_boot_setup);
64
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -070065/**
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)
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 *
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -070074 *
75 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
76 * in here instead. It is up to the 802.2 layer to carry protocol information.
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070078int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
Stephen Hemminger2e4ca752006-08-17 18:20:18 -070079 void *daddr, void *saddr, unsigned len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
Stephen Hemminger2e4ca752006-08-17 18:20:18 -070081 struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
Stephen Hemminger2e4ca752006-08-17 18:20:18 -070083 if (type != ETH_P_802_3)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 eth->h_proto = htons(type);
85 else
86 eth->h_proto = htons(len);
87
88 /*
Stephen Hemminger2e4ca752006-08-17 18:20:18 -070089 * Set the source hardware address.
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Stephen Hemminger2e4ca752006-08-17 18:20:18 -070092 if (!saddr)
93 saddr = dev->dev_addr;
94 memcpy(eth->h_source, saddr, dev->addr_len);
95
96 if (daddr) {
97 memcpy(eth->h_dest, daddr, dev->addr_len);
Jamal Hadi Salimf8d0e3f2006-02-23 16:18:01 -080098 return ETH_HLEN;
99 }
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 /*
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700102 * Anyway, the loopback-device should never use this function...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 */
104
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700105 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 memset(eth->h_dest, 0, dev->addr_len);
107 return ETH_HLEN;
108 }
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700109
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return -ETH_HLEN;
111}
112
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700113/**
114 * eth_rebuild_header- rebuild the Ethernet MAC header.
115 * @skb: socket buffer to update
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 *
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700117 * This is called after an ARP or IPV6 ndisc it's resolution on this
118 * sk_buff. We now let protocol (ARP) fill in the other fields.
119 *
120 * This routine CANNOT use cached dst->neigh!
121 * Really, it is used only when dst->neigh is wrong.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123int eth_rebuild_header(struct sk_buff *skb)
124{
125 struct ethhdr *eth = (struct ethhdr *)skb->data;
126 struct net_device *dev = skb->dev;
127
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700128 switch (eth->h_proto) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129#ifdef CONFIG_INET
130 case __constant_htons(ETH_P_IP):
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700131 return arp_find(eth->h_dest, skb);
132#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 default:
134 printk(KERN_DEBUG
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700135 "%s: unable to resolve type %X addresses.\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 dev->name, (int)eth->h_proto);
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700137
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
139 break;
140 }
141
142 return 0;
143}
144
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700145/**
146 * eth_type_trans - determine the packet's protocol ID.
147 * @skb: received socket data
148 * @dev: receiving network device
149 *
150 * The rule here is that we
151 * assume 802.3 if the type field is short enough to be a length.
152 * This is normal practice and works for any 'now in use' protocol.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 */
Alexey Dobriyanab611482005-07-12 12:08:43 -0700154__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
156 struct ethhdr *eth;
157 unsigned char *rawp;
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700158
David S. Millerba645c12005-09-27 16:03:05 -0700159 skb->mac.raw = skb->data;
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700160 skb_pull(skb, ETH_HLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 eth = eth_hdr(skb);
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700162
Kris Katterjohndbbc0982006-01-06 13:05:58 -0800163 if (is_multicast_ether_addr(eth->h_dest)) {
Stephen Hemminger360ac8e2005-10-25 15:03:41 -0700164 if (!compare_ether_addr(eth->h_dest, dev->broadcast))
David S. Millerba645c12005-09-27 16:03:05 -0700165 skb->pkt_type = PACKET_BROADCAST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 else
David S. Millerba645c12005-09-27 16:03:05 -0700167 skb->pkt_type = PACKET_MULTICAST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 }
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700169
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 /*
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700171 * This ALLMULTI check should be redundant by 1.4
172 * so don't forget to remove it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 *
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700174 * Seems, you forgot to remove it. All silly devices
175 * seems to set IFF_PROMISC.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 */
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700177
178 else if (1 /*dev->flags&IFF_PROMISC */ ) {
Stephen Hemminger360ac8e2005-10-25 15:03:41 -0700179 if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr)))
David S. Millerba645c12005-09-27 16:03:05 -0700180 skb->pkt_type = PACKET_OTHERHOST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 }
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 if (ntohs(eth->h_proto) >= 1536)
184 return eth->h_proto;
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700185
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 rawp = skb->data;
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 /*
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700189 * This is a magic hack to spot IPX packets. Older Novell breaks
190 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
191 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
192 * won't work for fault tolerant netware but does for the rest.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 */
194 if (*(unsigned short *)rawp == 0xFFFF)
195 return htons(ETH_P_802_3);
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700196
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 /*
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700198 * Real 802.2 LLC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 */
200 return htons(ETH_P_802_2);
201}
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700202EXPORT_SYMBOL(eth_type_trans);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700204/**
205 * eth_header_parse - extract hardware address from packet
206 * @skb: packet to extract header from
207 * @haddr: destination buffer
208 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr)
210{
211 struct ethhdr *eth = eth_hdr(skb);
212 memcpy(haddr, eth->h_source, ETH_ALEN);
213 return ETH_ALEN;
214}
215
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700216/**
217 * eth_header_cache - fill cache entry from neighbour
218 * @neigh: source neighbour
219 * @hh: destination cache entry
220 * Create an Ethernet header template from the neighbour.
221 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh)
223{
Al Virod77072e2006-09-28 14:20:34 -0700224 __be16 type = hh->hh_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 struct ethhdr *eth;
226 struct net_device *dev = neigh->dev;
227
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700228 eth = (struct ethhdr *)
229 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 if (type == __constant_htons(ETH_P_802_3))
232 return -1;
233
234 eth->h_proto = type;
235 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
236 memcpy(eth->h_dest, neigh->ha, dev->addr_len);
237 hh->hh_len = ETH_HLEN;
238 return 0;
239}
240
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700241/**
242 * eth_header_cache_update - update cache entry
243 * @hh: destination cache entry
244 * @dev: network device
245 * @haddr: new hardware address
246 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 * Called by Address Resolution module to notify changes in address.
248 */
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700249void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev,
250 unsigned char *haddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251{
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700252 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 haddr, dev->addr_len);
254}
255
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700256/**
257 * eth_mac_addr - set new Ethernet hardware address
258 * @dev: network device
259 * @p: socket address
260 * Change hardware address of device.
261 *
262 * This doesn't change hardware matching, so needs to be overridden
263 * for most real devices.
264 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265static int eth_mac_addr(struct net_device *dev, void *p)
266{
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700267 struct sockaddr *addr = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 if (netif_running(dev))
269 return -EBUSY;
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700270 memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 return 0;
272}
273
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700274/**
275 * eth_change_mtu - set new MTU size
276 * @dev: network device
277 * @new_mtu: new Maximum Transfer Unit
278 *
279 * Allow changing MTU size. Needs to be overridden for devices
280 * supporting jumbo frames.
281 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282static int eth_change_mtu(struct net_device *dev, int new_mtu)
283{
Kris Katterjohn46f25df2006-01-05 16:35:42 -0800284 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 return -EINVAL;
286 dev->mtu = new_mtu;
287 return 0;
288}
289
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700290/**
291 * ether_setup - setup Ethernet network device
292 * @dev: network device
293 * Fill in the fields of the device structure with Ethernet-generic values.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 */
295void ether_setup(struct net_device *dev)
296{
297 dev->change_mtu = eth_change_mtu;
298 dev->hard_header = eth_header;
299 dev->rebuild_header = eth_rebuild_header;
300 dev->set_mac_address = eth_mac_addr;
301 dev->hard_header_cache = eth_header_cache;
302 dev->header_cache_update= eth_header_cache_update;
303 dev->hard_header_parse = eth_header_parse;
304
305 dev->type = ARPHRD_ETHER;
306 dev->hard_header_len = ETH_HLEN;
Kris Katterjohn46f25df2006-01-05 16:35:42 -0800307 dev->mtu = ETH_DATA_LEN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 dev->addr_len = ETH_ALEN;
YOSHIFUJI Hideaki03d52d72007-02-09 23:24:44 +0900309 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
YOSHIFUJI Hideaki03d52d72007-02-09 23:24:44 +0900311
Stephen Hemminger2e4ca752006-08-17 18:20:18 -0700312 memset(dev->broadcast, 0xFF, ETH_ALEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
314}
315EXPORT_SYMBOL(ether_setup);
316
317/**
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700318 * alloc_etherdev - Allocates and sets up an Ethernet device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 * @sizeof_priv: Size of additional driver-private structure to be allocated
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700320 * for this Ethernet device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 *
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700322 * Fill in the fields of the device structure with Ethernet-generic
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 * values. Basically does everything except registering the device.
324 *
325 * Constructs a new net device, complete with a private data area of
Stephen Hemmingerd3e01f72006-08-17 18:18:53 -0700326 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 * this private data area.
328 */
329
330struct net_device *alloc_etherdev(int sizeof_priv)
331{
332 return alloc_netdev(sizeof_priv, "eth%d", ether_setup);
333}
334EXPORT_SYMBOL(alloc_etherdev);