1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
7 * Ethernet-type device handling.
9 * Version: @(#)eth.c 1.0.7 05/25/93
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 * Mark Evans, <evansmp@uhura.aston.ac.uk>
14 * Florian La Roche, <rzsfl@rz.uni-sb.de>
15 * Alan Cox, <gw4pts@gw4pts.ampr.org>
18 * Mr Linux : Arp problems
19 * Alan Cox : Generic queue tidyup (very tiny here)
20 * Alan Cox : eth_header ntohs should be htons
21 * Alan Cox : eth_rebuild_header missing an htons and
23 * Tegge : Arp bug fixes.
24 * Florian : Removed many unnecessary functions, code cleanup
25 * and changes for new arp and skbuff.
26 * Alan Cox : Redid header building to reflect new format.
27 * Alan Cox : ARP only when compiled with CONFIG_INET
28 * Greg Page : 802.2 and SNAP stuff.
29 * Alan Cox : MAC layer pointers/new format.
30 * Paul Gortmaker : eth_copy_and_sum shouldn't csum padding.
31 * Alan Cox : Protect against forwarding explosions with
32 * older network drivers and IFF_ALLMULTI.
33 * Christer Weinigel : Better rebuild header message.
34 * Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup().
36 #include <linux/module.h>
37 #include <linux/types.h>
38 #include <linux/kernel.h>
39 #include <linux/string.h>
41 #include <linux/socket.h>
43 #include <linux/inet.h>
45 #include <linux/netdevice.h>
46 #include <linux/nvmem-consumer.h>
47 #include <linux/etherdevice.h>
48 #include <linux/skbuff.h>
49 #include <linux/errno.h>
50 #include <linux/init.h>
51 #include <linux/if_ether.h>
52 #include <linux/of_net.h>
53 #include <linux/pci.h>
60 #include <net/flow_dissector.h>
61 #include <linux/uaccess.h>
62 #include <net/pkt_sched.h>
64 __setup("ether=", netdev_boot_setup);
67 * eth_header - create the Ethernet header
68 * @skb: buffer to alter
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)
76 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
79 int eth_header(struct sk_buff *skb, struct net_device *dev,
81 const void *daddr, const void *saddr, unsigned int len)
83 struct ethhdr *eth = skb_push(skb, ETH_HLEN);
85 if (type != ETH_P_802_3 && type != ETH_P_802_2)
86 eth->h_proto = htons(type);
88 eth->h_proto = htons(len);
91 * Set the source hardware address.
95 saddr = dev->dev_addr;
96 memcpy(eth->h_source, saddr, ETH_ALEN);
99 memcpy(eth->h_dest, daddr, ETH_ALEN);
104 * Anyway, the loopback-device should never use this function...
107 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
108 eth_zero_addr(eth->h_dest);
114 EXPORT_SYMBOL(eth_header);
117 * eth_get_headlen - determine the length of header for an ethernet frame
118 * @dev: pointer to network device
119 * @data: pointer to start of frame
120 * @len: total length of frame
122 * Make a best effort attempt to pull the length for all of the headers for
123 * a given frame in a linear buffer.
125 u32 eth_get_headlen(const struct net_device *dev, void *data, unsigned int len)
127 const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
128 const struct ethhdr *eth = (const struct ethhdr *)data;
129 struct flow_keys_basic keys;
131 /* this should never happen, but better safe than sorry */
132 if (unlikely(len < sizeof(*eth)))
135 /* parse any remaining L2/L3 headers, check for L4 */
136 if (!skb_flow_dissect_flow_keys_basic(dev_net(dev), NULL, &keys, data,
137 eth->h_proto, sizeof(*eth),
139 return max_t(u32, keys.control.thoff, sizeof(*eth));
141 /* parse for any L4 headers */
142 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
144 EXPORT_SYMBOL(eth_get_headlen);
147 * eth_type_trans - determine the packet's protocol ID.
148 * @skb: received socket data
149 * @dev: receiving network device
151 * The rule here is that we
152 * assume 802.3 if the type field is short enough to be a length.
153 * This is normal practice and works for any 'now in use' protocol.
155 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
157 unsigned short _service_access_point;
158 const unsigned short *sap;
159 const struct ethhdr *eth;
162 skb_reset_mac_header(skb);
164 eth = (struct ethhdr *)skb->data;
165 skb_pull_inline(skb, ETH_HLEN);
167 eth_skb_pkt_type(skb, dev);
170 * Some variants of DSA tagging don't have an ethertype field
171 * at all, so we check here whether one of those tagging
172 * variants has been configured on the receiving interface,
173 * and if so, set skb->protocol without looking at the packet.
174 * The DSA tagging protocol may be able to decode some but not all
175 * traffic (for example only for management). In that case give it the
176 * option to filter the packets from which it can decode source port
179 if (unlikely(netdev_uses_dsa(dev)) && dsa_can_decode(skb, dev))
180 return htons(ETH_P_XDSA);
182 if (likely(eth_proto_is_802_3(eth->h_proto)))
186 * This is a magic hack to spot IPX packets. Older Novell breaks
187 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
188 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
189 * won't work for fault tolerant netware but does for the rest.
191 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
192 if (sap && *sap == 0xFFFF)
193 return htons(ETH_P_802_3);
198 return htons(ETH_P_802_2);
200 EXPORT_SYMBOL(eth_type_trans);
203 * eth_header_parse - extract hardware address from packet
204 * @skb: packet to extract header from
205 * @haddr: destination buffer
207 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
209 const struct ethhdr *eth = eth_hdr(skb);
210 memcpy(haddr, eth->h_source, ETH_ALEN);
213 EXPORT_SYMBOL(eth_header_parse);
216 * eth_header_cache - fill cache entry from neighbour
217 * @neigh: source neighbour
218 * @hh: destination cache entry
219 * @type: Ethernet type field
221 * Create an Ethernet header template from the neighbour.
223 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
226 const struct net_device *dev = neigh->dev;
228 eth = (struct ethhdr *)
229 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
231 if (type == htons(ETH_P_802_3))
235 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
236 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
238 /* Pairs with READ_ONCE() in neigh_resolve_output(),
239 * neigh_hh_output() and neigh_update_hhs().
241 smp_store_release(&hh->hh_len, ETH_HLEN);
245 EXPORT_SYMBOL(eth_header_cache);
248 * eth_header_cache_update - update cache entry
249 * @hh: destination cache entry
250 * @dev: network device
251 * @haddr: new hardware address
253 * Called by Address Resolution module to notify changes in address.
255 void eth_header_cache_update(struct hh_cache *hh,
256 const struct net_device *dev,
257 const unsigned char *haddr)
259 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
262 EXPORT_SYMBOL(eth_header_cache_update);
265 * eth_header_parser_protocol - extract protocol from L2 header
266 * @skb: packet to extract protocol from
268 __be16 eth_header_parse_protocol(const struct sk_buff *skb)
270 const struct ethhdr *eth = eth_hdr(skb);
274 EXPORT_SYMBOL(eth_header_parse_protocol);
277 * eth_prepare_mac_addr_change - prepare for mac change
278 * @dev: network device
281 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
283 struct sockaddr *addr = p;
285 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
287 if (!is_valid_ether_addr(addr->sa_data))
288 return -EADDRNOTAVAIL;
291 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
294 * eth_commit_mac_addr_change - commit mac change
295 * @dev: network device
298 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
300 struct sockaddr *addr = p;
302 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
304 EXPORT_SYMBOL(eth_commit_mac_addr_change);
307 * eth_mac_addr - set new Ethernet hardware address
308 * @dev: network device
311 * Change hardware address of device.
313 * This doesn't change hardware matching, so needs to be overridden
314 * for most real devices.
316 int eth_mac_addr(struct net_device *dev, void *p)
320 ret = eth_prepare_mac_addr_change(dev, p);
323 eth_commit_mac_addr_change(dev, p);
326 EXPORT_SYMBOL(eth_mac_addr);
328 int eth_validate_addr(struct net_device *dev)
330 if (!is_valid_ether_addr(dev->dev_addr))
331 return -EADDRNOTAVAIL;
335 EXPORT_SYMBOL(eth_validate_addr);
337 const struct header_ops eth_header_ops ____cacheline_aligned = {
338 .create = eth_header,
339 .parse = eth_header_parse,
340 .cache = eth_header_cache,
341 .cache_update = eth_header_cache_update,
342 .parse_protocol = eth_header_parse_protocol,
346 * ether_setup - setup Ethernet network device
347 * @dev: network device
349 * Fill in the fields of the device structure with Ethernet-generic values.
351 void ether_setup(struct net_device *dev)
353 dev->header_ops = ð_header_ops;
354 dev->type = ARPHRD_ETHER;
355 dev->hard_header_len = ETH_HLEN;
356 dev->min_header_len = ETH_HLEN;
357 dev->mtu = ETH_DATA_LEN;
358 dev->min_mtu = ETH_MIN_MTU;
359 dev->max_mtu = ETH_DATA_LEN;
360 dev->addr_len = ETH_ALEN;
361 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
362 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
363 dev->priv_flags |= IFF_TX_SKB_SHARING;
365 eth_broadcast_addr(dev->broadcast);
368 EXPORT_SYMBOL(ether_setup);
371 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
372 * @sizeof_priv: Size of additional driver-private structure to be allocated
373 * for this Ethernet device
374 * @txqs: The number of TX queues this device has.
375 * @rxqs: The number of RX queues this device has.
377 * Fill in the fields of the device structure with Ethernet-generic
378 * values. Basically does everything except registering the device.
380 * Constructs a new net device, complete with a private data area of
381 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
382 * this private data area.
385 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
388 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
389 ether_setup, txqs, rxqs);
391 EXPORT_SYMBOL(alloc_etherdev_mqs);
393 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
395 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
397 EXPORT_SYMBOL(sysfs_format_mac);
399 struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
401 const struct packet_offload *ptype;
402 unsigned int hlen, off_eth;
403 struct sk_buff *pp = NULL;
404 struct ethhdr *eh, *eh2;
409 off_eth = skb_gro_offset(skb);
410 hlen = off_eth + sizeof(*eh);
411 eh = skb_gro_header_fast(skb, off_eth);
412 if (skb_gro_header_hard(skb, hlen)) {
413 eh = skb_gro_header_slow(skb, hlen, off_eth);
420 list_for_each_entry(p, head, list) {
421 if (!NAPI_GRO_CB(p)->same_flow)
424 eh2 = (struct ethhdr *)(p->data + off_eth);
425 if (compare_ether_header(eh, eh2)) {
426 NAPI_GRO_CB(p)->same_flow = 0;
434 ptype = gro_find_receive_by_type(type);
440 skb_gro_pull(skb, sizeof(*eh));
441 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
442 pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
447 skb_gro_flush_final(skb, pp, flush);
451 EXPORT_SYMBOL(eth_gro_receive);
453 int eth_gro_complete(struct sk_buff *skb, int nhoff)
455 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
456 __be16 type = eh->h_proto;
457 struct packet_offload *ptype;
460 if (skb->encapsulation)
461 skb_set_inner_mac_header(skb, nhoff);
464 ptype = gro_find_complete_by_type(type);
466 err = ptype->callbacks.gro_complete(skb, nhoff +
467 sizeof(struct ethhdr));
472 EXPORT_SYMBOL(eth_gro_complete);
474 static struct packet_offload eth_packet_offload __read_mostly = {
475 .type = cpu_to_be16(ETH_P_TEB),
478 .gro_receive = eth_gro_receive,
479 .gro_complete = eth_gro_complete,
483 static int __init eth_offload_init(void)
485 dev_add_offload(ð_packet_offload);
490 fs_initcall(eth_offload_init);
492 unsigned char * __weak arch_get_platform_mac_address(void)
497 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
499 const unsigned char *addr = NULL;
502 addr = of_get_mac_address(dev->of_node);
503 if (IS_ERR_OR_NULL(addr))
504 addr = arch_get_platform_mac_address();
509 ether_addr_copy(mac_addr, addr);
513 EXPORT_SYMBOL(eth_platform_get_mac_address);
516 * Obtain the MAC address from an nvmem cell named 'mac-address' associated
519 * @dev: Device with which the mac-address cell is associated.
520 * @addrbuf: Buffer to which the MAC address will be copied on success.
522 * Returns 0 on success or a negative error number on failure.
524 int nvmem_get_mac_address(struct device *dev, void *addrbuf)
526 struct nvmem_cell *cell;
530 cell = nvmem_cell_get(dev, "mac-address");
532 return PTR_ERR(cell);
534 mac = nvmem_cell_read(cell, &len);
535 nvmem_cell_put(cell);
540 if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
545 ether_addr_copy(addrbuf, mac);
550 EXPORT_SYMBOL(nvmem_get_mac_address);