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.
6 * Ethernet-type device handling.
8 * Version: @(#)eth.c 1.0.7 05/25/93
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>
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
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().
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.
40 #include <linux/module.h>
41 #include <linux/types.h>
42 #include <linux/kernel.h>
43 #include <linux/string.h>
45 #include <linux/socket.h>
47 #include <linux/inet.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>
61 #include <linux/uaccess.h>
63 __setup("ether=", netdev_boot_setup);
66 * eth_header - create the Ethernet header
67 * @skb: buffer to alter
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)
75 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
78 int eth_header(struct sk_buff *skb, struct net_device *dev,
80 const void *daddr, const void *saddr, unsigned int len)
82 struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
84 if (type != ETH_P_802_3 && type != ETH_P_802_2)
85 eth->h_proto = htons(type);
87 eth->h_proto = htons(len);
90 * Set the source hardware address.
94 saddr = dev->dev_addr;
95 memcpy(eth->h_source, saddr, ETH_ALEN);
98 memcpy(eth->h_dest, daddr, ETH_ALEN);
103 * Anyway, the loopback-device should never use this function...
106 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
107 memset(eth->h_dest, 0, ETH_ALEN);
113 EXPORT_SYMBOL(eth_header);
116 * eth_rebuild_header- rebuild the Ethernet MAC header.
117 * @skb: socket buffer to update
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.
122 * This routine CANNOT use cached dst->neigh!
123 * Really, it is used only when dst->neigh is wrong.
125 int eth_rebuild_header(struct sk_buff *skb)
127 struct ethhdr *eth = (struct ethhdr *)skb->data;
128 struct net_device *dev = skb->dev;
130 switch (eth->h_proto) {
132 case htons(ETH_P_IP):
133 return arp_find(eth->h_dest, skb);
137 "%s: unable to resolve type %X addresses.\n",
138 dev->name, ntohs(eth->h_proto));
140 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
146 EXPORT_SYMBOL(eth_rebuild_header);
149 * eth_get_headlen - determine the the length of header for an ethernet frame
150 * @data: pointer to start of frame
151 * @len: total length of frame
153 * Make a best effort attempt to pull the length for all of the headers for
154 * a given frame in a linear buffer.
156 u32 eth_get_headlen(void *data, unsigned int len)
158 const struct ethhdr *eth = (const struct ethhdr *)data;
159 struct flow_keys keys;
161 /* this should never happen, but better safe than sorry */
162 if (len < sizeof(*eth))
165 /* parse any remaining L2/L3 headers, check for L4 */
166 if (!__skb_flow_dissect(NULL, &keys, data,
167 eth->h_proto, sizeof(*eth), len))
168 return max_t(u32, keys.thoff, sizeof(*eth));
170 /* parse for any L4 headers */
171 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
173 EXPORT_SYMBOL(eth_get_headlen);
176 * eth_type_trans - determine the packet's protocol ID.
177 * @skb: received socket data
178 * @dev: receiving network device
180 * The rule here is that we
181 * assume 802.3 if the type field is short enough to be a length.
182 * This is normal practice and works for any 'now in use' protocol.
184 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
186 unsigned short _service_access_point;
187 const unsigned short *sap;
188 const struct ethhdr *eth;
191 skb_reset_mac_header(skb);
192 skb_pull_inline(skb, ETH_HLEN);
195 if (unlikely(is_multicast_ether_addr(eth->h_dest))) {
196 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
197 skb->pkt_type = PACKET_BROADCAST;
199 skb->pkt_type = PACKET_MULTICAST;
201 else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
203 skb->pkt_type = PACKET_OTHERHOST;
206 * Some variants of DSA tagging don't have an ethertype field
207 * at all, so we check here whether one of those tagging
208 * variants has been configured on the receiving interface,
209 * and if so, set skb->protocol without looking at the packet.
211 if (unlikely(netdev_uses_dsa(dev)))
212 return htons(ETH_P_XDSA);
214 if (likely(ntohs(eth->h_proto) >= ETH_P_802_3_MIN))
218 * This is a magic hack to spot IPX packets. Older Novell breaks
219 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
220 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
221 * won't work for fault tolerant netware but does for the rest.
223 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
224 if (sap && *sap == 0xFFFF)
225 return htons(ETH_P_802_3);
230 return htons(ETH_P_802_2);
232 EXPORT_SYMBOL(eth_type_trans);
235 * eth_header_parse - extract hardware address from packet
236 * @skb: packet to extract header from
237 * @haddr: destination buffer
239 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
241 const struct ethhdr *eth = eth_hdr(skb);
242 memcpy(haddr, eth->h_source, ETH_ALEN);
245 EXPORT_SYMBOL(eth_header_parse);
248 * eth_header_cache - fill cache entry from neighbour
249 * @neigh: source neighbour
250 * @hh: destination cache entry
251 * @type: Ethernet type field
253 * Create an Ethernet header template from the neighbour.
255 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
258 const struct net_device *dev = neigh->dev;
260 eth = (struct ethhdr *)
261 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
263 if (type == htons(ETH_P_802_3))
267 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
268 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
269 hh->hh_len = ETH_HLEN;
272 EXPORT_SYMBOL(eth_header_cache);
275 * eth_header_cache_update - update cache entry
276 * @hh: destination cache entry
277 * @dev: network device
278 * @haddr: new hardware address
280 * Called by Address Resolution module to notify changes in address.
282 void eth_header_cache_update(struct hh_cache *hh,
283 const struct net_device *dev,
284 const unsigned char *haddr)
286 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
289 EXPORT_SYMBOL(eth_header_cache_update);
292 * eth_prepare_mac_addr_change - prepare for mac change
293 * @dev: network device
296 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
298 struct sockaddr *addr = p;
300 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
302 if (!is_valid_ether_addr(addr->sa_data))
303 return -EADDRNOTAVAIL;
306 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
309 * eth_commit_mac_addr_change - commit mac change
310 * @dev: network device
313 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
315 struct sockaddr *addr = p;
317 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
319 EXPORT_SYMBOL(eth_commit_mac_addr_change);
322 * eth_mac_addr - set new Ethernet hardware address
323 * @dev: network device
326 * Change hardware address of device.
328 * This doesn't change hardware matching, so needs to be overridden
329 * for most real devices.
331 int eth_mac_addr(struct net_device *dev, void *p)
335 ret = eth_prepare_mac_addr_change(dev, p);
338 eth_commit_mac_addr_change(dev, p);
341 EXPORT_SYMBOL(eth_mac_addr);
344 * eth_change_mtu - set new MTU size
345 * @dev: network device
346 * @new_mtu: new Maximum Transfer Unit
348 * Allow changing MTU size. Needs to be overridden for devices
349 * supporting jumbo frames.
351 int eth_change_mtu(struct net_device *dev, int new_mtu)
353 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
358 EXPORT_SYMBOL(eth_change_mtu);
360 int eth_validate_addr(struct net_device *dev)
362 if (!is_valid_ether_addr(dev->dev_addr))
363 return -EADDRNOTAVAIL;
367 EXPORT_SYMBOL(eth_validate_addr);
369 const struct header_ops eth_header_ops ____cacheline_aligned = {
370 .create = eth_header,
371 .parse = eth_header_parse,
372 .rebuild = eth_rebuild_header,
373 .cache = eth_header_cache,
374 .cache_update = eth_header_cache_update,
378 * ether_setup - setup Ethernet network device
379 * @dev: network device
381 * Fill in the fields of the device structure with Ethernet-generic values.
383 void ether_setup(struct net_device *dev)
385 dev->header_ops = ð_header_ops;
386 dev->type = ARPHRD_ETHER;
387 dev->hard_header_len = ETH_HLEN;
388 dev->mtu = ETH_DATA_LEN;
389 dev->addr_len = ETH_ALEN;
390 dev->tx_queue_len = 1000; /* Ethernet wants good queues */
391 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
392 dev->priv_flags |= IFF_TX_SKB_SHARING;
394 memset(dev->broadcast, 0xFF, ETH_ALEN);
397 EXPORT_SYMBOL(ether_setup);
400 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
401 * @sizeof_priv: Size of additional driver-private structure to be allocated
402 * for this Ethernet device
403 * @txqs: The number of TX queues this device has.
404 * @rxqs: The number of RX queues this device has.
406 * Fill in the fields of the device structure with Ethernet-generic
407 * values. Basically does everything except registering the device.
409 * Constructs a new net device, complete with a private data area of
410 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
411 * this private data area.
414 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
417 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
418 ether_setup, txqs, rxqs);
420 EXPORT_SYMBOL(alloc_etherdev_mqs);
422 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
424 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
426 EXPORT_SYMBOL(sysfs_format_mac);
428 struct sk_buff **eth_gro_receive(struct sk_buff **head,
431 struct sk_buff *p, **pp = NULL;
432 struct ethhdr *eh, *eh2;
433 unsigned int hlen, off_eth;
434 const struct packet_offload *ptype;
438 off_eth = skb_gro_offset(skb);
439 hlen = off_eth + sizeof(*eh);
440 eh = skb_gro_header_fast(skb, off_eth);
441 if (skb_gro_header_hard(skb, hlen)) {
442 eh = skb_gro_header_slow(skb, hlen, off_eth);
449 for (p = *head; p; p = p->next) {
450 if (!NAPI_GRO_CB(p)->same_flow)
453 eh2 = (struct ethhdr *)(p->data + off_eth);
454 if (compare_ether_header(eh, eh2)) {
455 NAPI_GRO_CB(p)->same_flow = 0;
463 ptype = gro_find_receive_by_type(type);
469 skb_gro_pull(skb, sizeof(*eh));
470 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
471 pp = ptype->callbacks.gro_receive(head, skb);
476 NAPI_GRO_CB(skb)->flush |= flush;
480 EXPORT_SYMBOL(eth_gro_receive);
482 int eth_gro_complete(struct sk_buff *skb, int nhoff)
484 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
485 __be16 type = eh->h_proto;
486 struct packet_offload *ptype;
489 if (skb->encapsulation)
490 skb_set_inner_mac_header(skb, nhoff);
493 ptype = gro_find_complete_by_type(type);
495 err = ptype->callbacks.gro_complete(skb, nhoff +
496 sizeof(struct ethhdr));
501 EXPORT_SYMBOL(eth_gro_complete);
503 static struct packet_offload eth_packet_offload __read_mostly = {
504 .type = cpu_to_be16(ETH_P_TEB),
506 .gro_receive = eth_gro_receive,
507 .gro_complete = eth_gro_complete,
511 static int __init eth_offload_init(void)
513 dev_add_offload(ð_packet_offload);
518 fs_initcall(eth_offload_init);