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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>
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/sched.h>
44#include <linux/string.h>
45#include <linux/mm.h>
46#include <linux/socket.h>
47#include <linux/in.h>
48#include <linux/inet.h>
49#include <linux/ip.h>
50#include <linux/netdevice.h>
51#include <linux/etherdevice.h>
52#include <linux/skbuff.h>
53#include <linux/errno.h>
54#include <linux/config.h>
55#include <linux/init.h>
56#include <net/dst.h>
57#include <net/arp.h>
58#include <net/sock.h>
59#include <net/ipv6.h>
60#include <net/ip.h>
61#include <asm/uaccess.h>
62#include <asm/system.h>
63#include <asm/checksum.h>
64
Linus Torvalds1da177e2005-04-16 15:20:36 -070065__setup("ether=", netdev_boot_setup);
66
67/*
68 * Create the Ethernet MAC header for an arbitrary protocol layer
69 *
70 * saddr=NULL means use device source address
71 * daddr=NULL means leave destination address (eg unresolved arp)
72 */
73
74int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
75 void *daddr, void *saddr, unsigned len)
76{
77 struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN);
78
79 /*
80 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
81 * in here instead. It is up to the 802.2 layer to carry protocol information.
82 */
83
84 if(type!=ETH_P_802_3)
85 eth->h_proto = htons(type);
86 else
87 eth->h_proto = htons(len);
88
89 /*
90 * Set the source hardware address.
91 */
92
Denis Vlasenkoff593c52005-06-28 15:49:06 -070093 if(!saddr)
94 saddr = dev->dev_addr;
95 memcpy(eth->h_source,saddr,dev->addr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 /*
98 * Anyway, the loopback-device should never use this function...
99 */
100
101 if (dev->flags & (IFF_LOOPBACK|IFF_NOARP))
102 {
103 memset(eth->h_dest, 0, dev->addr_len);
104 return ETH_HLEN;
105 }
106
107 if(daddr)
108 {
109 memcpy(eth->h_dest,daddr,dev->addr_len);
110 return ETH_HLEN;
111 }
112
113 return -ETH_HLEN;
114}
115
116
117/*
118 * Rebuild the Ethernet MAC header. This is called after an ARP
119 * (or in future other address resolution) has completed on this
120 * sk_buff. We now let 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 */
125
126int 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 {
133#ifdef CONFIG_INET
134 case __constant_htons(ETH_P_IP):
135 return arp_find(eth->h_dest, skb);
136#endif
137 default:
138 printk(KERN_DEBUG
139 "%s: unable to resolve type %X addresses.\n",
140 dev->name, (int)eth->h_proto);
141
142 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
143 break;
144 }
145
146 return 0;
147}
148
David S. Millerba645c12005-09-27 16:03:05 -0700149static inline unsigned int compare_eth_addr(const unsigned char *__a, const unsigned char *__b)
150{
151 const unsigned short *dest = (unsigned short *) __a;
152 const unsigned short *devaddr = (unsigned short *) __b;
153 unsigned int res;
154
155 BUILD_BUG_ON(ETH_ALEN != 6);
156 res = ((dest[0] ^ devaddr[0]) |
157 (dest[1] ^ devaddr[1]) |
158 (dest[2] ^ devaddr[2])) != 0;
159
160 return res;
161}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163/*
164 * Determine the packet's protocol ID. The rule here is that we
165 * assume 802.3 if the type field is short enough to be a length.
166 * This is normal practice and works for any 'now in use' protocol.
167 */
168
Alexey Dobriyanab611482005-07-12 12:08:43 -0700169__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170{
171 struct ethhdr *eth;
172 unsigned char *rawp;
173
David S. Millerba645c12005-09-27 16:03:05 -0700174 skb->mac.raw = skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 skb_pull(skb,ETH_HLEN);
176 eth = eth_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
David S. Millerba645c12005-09-27 16:03:05 -0700178 if (*eth->h_dest&1) {
179 if (!compare_eth_addr(eth->h_dest, dev->broadcast))
180 skb->pkt_type = PACKET_BROADCAST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 else
David S. Millerba645c12005-09-27 16:03:05 -0700182 skb->pkt_type = PACKET_MULTICAST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 }
184
185 /*
186 * This ALLMULTI check should be redundant by 1.4
187 * so don't forget to remove it.
188 *
189 * Seems, you forgot to remove it. All silly devices
190 * seems to set IFF_PROMISC.
191 */
192
David S. Millerba645c12005-09-27 16:03:05 -0700193 else if(1 /*dev->flags&IFF_PROMISC*/) {
194 if (unlikely(!compare_eth_addr(eth->h_dest, dev->dev_addr)))
195 skb->pkt_type = PACKET_OTHERHOST;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 }
197
198 if (ntohs(eth->h_proto) >= 1536)
199 return eth->h_proto;
200
201 rawp = skb->data;
202
203 /*
204 * This is a magic hack to spot IPX packets. Older Novell breaks
205 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
206 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
207 * won't work for fault tolerant netware but does for the rest.
208 */
209 if (*(unsigned short *)rawp == 0xFFFF)
210 return htons(ETH_P_802_3);
211
212 /*
213 * Real 802.2 LLC
214 */
215 return htons(ETH_P_802_2);
216}
217
218static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr)
219{
220 struct ethhdr *eth = eth_hdr(skb);
221 memcpy(haddr, eth->h_source, ETH_ALEN);
222 return ETH_ALEN;
223}
224
225int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh)
226{
227 unsigned short type = hh->hh_type;
228 struct ethhdr *eth;
229 struct net_device *dev = neigh->dev;
230
231 eth = (struct ethhdr*)
232 (((u8*)hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
233
234 if (type == __constant_htons(ETH_P_802_3))
235 return -1;
236
237 eth->h_proto = type;
238 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
239 memcpy(eth->h_dest, neigh->ha, dev->addr_len);
240 hh->hh_len = ETH_HLEN;
241 return 0;
242}
243
244/*
245 * Called by Address Resolution module to notify changes in address.
246 */
247
248void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr)
249{
250 memcpy(((u8*)hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
251 haddr, dev->addr_len);
252}
253
254EXPORT_SYMBOL(eth_type_trans);
255
256static int eth_mac_addr(struct net_device *dev, void *p)
257{
258 struct sockaddr *addr=p;
259 if (netif_running(dev))
260 return -EBUSY;
261 memcpy(dev->dev_addr, addr->sa_data,dev->addr_len);
262 return 0;
263}
264
265static int eth_change_mtu(struct net_device *dev, int new_mtu)
266{
267 if ((new_mtu < 68) || (new_mtu > 1500))
268 return -EINVAL;
269 dev->mtu = new_mtu;
270 return 0;
271}
272
273/*
274 * Fill in the fields of the device structure with ethernet-generic values.
275 */
276void ether_setup(struct net_device *dev)
277{
278 dev->change_mtu = eth_change_mtu;
279 dev->hard_header = eth_header;
280 dev->rebuild_header = eth_rebuild_header;
281 dev->set_mac_address = eth_mac_addr;
282 dev->hard_header_cache = eth_header_cache;
283 dev->header_cache_update= eth_header_cache_update;
284 dev->hard_header_parse = eth_header_parse;
285
286 dev->type = ARPHRD_ETHER;
287 dev->hard_header_len = ETH_HLEN;
288 dev->mtu = 1500; /* eth_mtu */
289 dev->addr_len = ETH_ALEN;
290 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
291 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
292
293 memset(dev->broadcast,0xFF, ETH_ALEN);
294
295}
296EXPORT_SYMBOL(ether_setup);
297
298/**
299 * alloc_etherdev - Allocates and sets up an ethernet device
300 * @sizeof_priv: Size of additional driver-private structure to be allocated
301 * for this ethernet device
302 *
303 * Fill in the fields of the device structure with ethernet-generic
304 * values. Basically does everything except registering the device.
305 *
306 * Constructs a new net device, complete with a private data area of
307 * size @sizeof_priv. A 32-byte (not bit) alignment is enforced for
308 * this private data area.
309 */
310
311struct net_device *alloc_etherdev(int sizeof_priv)
312{
313 return alloc_netdev(sizeof_priv, "eth%d", ether_setup);
314}
315EXPORT_SYMBOL(alloc_etherdev);