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>
62 #include <linux/uaccess.h>
63 #include <net/pkt_sched.h>
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 = 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 eth_zero_addr(eth->h_dest);
113 EXPORT_SYMBOL(eth_header);
116 * eth_get_headlen - determine the length of header for an ethernet frame
117 * @dev: pointer to network device
118 * @data: pointer to start of frame
119 * @len: total length of frame
121 * Make a best effort attempt to pull the length for all of the headers for
122 * a given frame in a linear buffer.
124 u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len)
126 const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
127 const struct ethhdr *eth = (const struct ethhdr *)data;
128 struct flow_keys_basic keys;
130 /* this should never happen, but better safe than sorry */
131 if (unlikely(len < sizeof(*eth)))
134 /* parse any remaining L2/L3 headers, check for L4 */
135 if (!skb_flow_dissect_flow_keys_basic(dev_net(dev), NULL, &keys, data,
136 eth->h_proto, sizeof(*eth),
138 return max_t(u32, keys.control.thoff, sizeof(*eth));
140 /* parse for any L4 headers */
141 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
143 EXPORT_SYMBOL(eth_get_headlen);
146 * eth_type_trans - determine the packet's protocol ID.
147 * @skb: received socket data
148 * @dev: receiving network device
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.
154 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
156 unsigned short _service_access_point;
157 const unsigned short *sap;
158 const struct ethhdr *eth;
161 skb_reset_mac_header(skb);
163 eth = (struct ethhdr *)skb->data;
164 skb_pull_inline(skb, ETH_HLEN);
166 if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
168 if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
169 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
170 skb->pkt_type = PACKET_BROADCAST;
172 skb->pkt_type = PACKET_MULTICAST;
174 skb->pkt_type = PACKET_OTHERHOST;
179 * Some variants of DSA tagging don't have an ethertype field
180 * at all, so we check here whether one of those tagging
181 * variants has been configured on the receiving interface,
182 * and if so, set skb->protocol without looking at the packet.
184 if (unlikely(netdev_uses_dsa(dev)))
185 return htons(ETH_P_XDSA);
187 if (likely(eth_proto_is_802_3(eth->h_proto)))
191 * This is a magic hack to spot IPX packets. Older Novell breaks
192 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
193 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
194 * won't work for fault tolerant netware but does for the rest.
196 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
197 if (sap && *sap == 0xFFFF)
198 return htons(ETH_P_802_3);
203 return htons(ETH_P_802_2);
205 EXPORT_SYMBOL(eth_type_trans);
208 * eth_header_parse - extract hardware address from packet
209 * @skb: packet to extract header from
210 * @haddr: destination buffer
212 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
214 const struct ethhdr *eth = eth_hdr(skb);
215 memcpy(haddr, eth->h_source, ETH_ALEN);
218 EXPORT_SYMBOL(eth_header_parse);
221 * eth_header_cache - fill cache entry from neighbour
222 * @neigh: source neighbour
223 * @hh: destination cache entry
224 * @type: Ethernet type field
226 * Create an Ethernet header template from the neighbour.
228 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
231 const struct net_device *dev = neigh->dev;
233 eth = (struct ethhdr *)
234 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
236 if (type == htons(ETH_P_802_3))
240 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
241 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
243 /* Pairs with READ_ONCE() in neigh_resolve_output(),
244 * neigh_hh_output() and neigh_update_hhs().
246 smp_store_release(&hh->hh_len, ETH_HLEN);
250 EXPORT_SYMBOL(eth_header_cache);
253 * eth_header_cache_update - update cache entry
254 * @hh: destination cache entry
255 * @dev: network device
256 * @haddr: new hardware address
258 * Called by Address Resolution module to notify changes in address.
260 void eth_header_cache_update(struct hh_cache *hh,
261 const struct net_device *dev,
262 const unsigned char *haddr)
264 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
267 EXPORT_SYMBOL(eth_header_cache_update);
270 * eth_header_parse_protocol - extract protocol from L2 header
271 * @skb: packet to extract protocol from
273 __be16 eth_header_parse_protocol(const struct sk_buff *skb)
275 const struct ethhdr *eth = eth_hdr(skb);
279 EXPORT_SYMBOL(eth_header_parse_protocol);
282 * eth_prepare_mac_addr_change - prepare for mac change
283 * @dev: network device
286 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
288 struct sockaddr *addr = p;
290 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
292 if (!is_valid_ether_addr(addr->sa_data))
293 return -EADDRNOTAVAIL;
296 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
299 * eth_commit_mac_addr_change - commit mac change
300 * @dev: network device
303 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
305 struct sockaddr *addr = p;
307 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
309 EXPORT_SYMBOL(eth_commit_mac_addr_change);
312 * eth_mac_addr - set new Ethernet hardware address
313 * @dev: network device
316 * Change hardware address of device.
318 * This doesn't change hardware matching, so needs to be overridden
319 * for most real devices.
321 int eth_mac_addr(struct net_device *dev, void *p)
325 ret = eth_prepare_mac_addr_change(dev, p);
328 eth_commit_mac_addr_change(dev, p);
331 EXPORT_SYMBOL(eth_mac_addr);
333 int eth_validate_addr(struct net_device *dev)
335 if (!is_valid_ether_addr(dev->dev_addr))
336 return -EADDRNOTAVAIL;
340 EXPORT_SYMBOL(eth_validate_addr);
342 const struct header_ops eth_header_ops ____cacheline_aligned = {
343 .create = eth_header,
344 .parse = eth_header_parse,
345 .cache = eth_header_cache,
346 .cache_update = eth_header_cache_update,
347 .parse_protocol = eth_header_parse_protocol,
351 * ether_setup - setup Ethernet network device
352 * @dev: network device
354 * Fill in the fields of the device structure with Ethernet-generic values.
356 void ether_setup(struct net_device *dev)
358 dev->header_ops = ð_header_ops;
359 dev->type = ARPHRD_ETHER;
360 dev->hard_header_len = ETH_HLEN;
361 dev->min_header_len = ETH_HLEN;
362 dev->mtu = ETH_DATA_LEN;
363 dev->min_mtu = ETH_MIN_MTU;
364 dev->max_mtu = ETH_DATA_LEN;
365 dev->addr_len = ETH_ALEN;
366 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
367 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
368 dev->priv_flags |= IFF_TX_SKB_SHARING;
370 eth_broadcast_addr(dev->broadcast);
373 EXPORT_SYMBOL(ether_setup);
376 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
377 * @sizeof_priv: Size of additional driver-private structure to be allocated
378 * for this Ethernet device
379 * @txqs: The number of TX queues this device has.
380 * @rxqs: The number of RX queues this device has.
382 * Fill in the fields of the device structure with Ethernet-generic
383 * values. Basically does everything except registering the device.
385 * Constructs a new net device, complete with a private data area of
386 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
387 * this private data area.
390 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
393 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
394 ether_setup, txqs, rxqs);
396 EXPORT_SYMBOL(alloc_etherdev_mqs);
398 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
400 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
402 EXPORT_SYMBOL(sysfs_format_mac);
404 struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
406 const struct packet_offload *ptype;
407 unsigned int hlen, off_eth;
408 struct sk_buff *pp = NULL;
409 struct ethhdr *eh, *eh2;
414 off_eth = skb_gro_offset(skb);
415 hlen = off_eth + sizeof(*eh);
416 eh = skb_gro_header_fast(skb, off_eth);
417 if (skb_gro_header_hard(skb, hlen)) {
418 eh = skb_gro_header_slow(skb, hlen, off_eth);
425 list_for_each_entry(p, head, list) {
426 if (!NAPI_GRO_CB(p)->same_flow)
429 eh2 = (struct ethhdr *)(p->data + off_eth);
430 if (compare_ether_header(eh, eh2)) {
431 NAPI_GRO_CB(p)->same_flow = 0;
439 ptype = gro_find_receive_by_type(type);
445 skb_gro_pull(skb, sizeof(*eh));
446 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
448 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
449 ipv6_gro_receive, inet_gro_receive,
455 skb_gro_flush_final(skb, pp, flush);
459 EXPORT_SYMBOL(eth_gro_receive);
461 int eth_gro_complete(struct sk_buff *skb, int nhoff)
463 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
464 __be16 type = eh->h_proto;
465 struct packet_offload *ptype;
468 if (skb->encapsulation)
469 skb_set_inner_mac_header(skb, nhoff);
472 ptype = gro_find_complete_by_type(type);
474 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
475 ipv6_gro_complete, inet_gro_complete,
476 skb, nhoff + sizeof(*eh));
481 EXPORT_SYMBOL(eth_gro_complete);
483 static struct packet_offload eth_packet_offload __read_mostly = {
484 .type = cpu_to_be16(ETH_P_TEB),
487 .gro_receive = eth_gro_receive,
488 .gro_complete = eth_gro_complete,
492 static int __init eth_offload_init(void)
494 dev_add_offload(ð_packet_offload);
499 fs_initcall(eth_offload_init);
501 unsigned char * __weak arch_get_platform_mac_address(void)
506 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
511 ret = of_get_mac_address(dev->of_node, mac_addr);
515 addr = arch_get_platform_mac_address();
519 ether_addr_copy(mac_addr, addr);
523 EXPORT_SYMBOL(eth_platform_get_mac_address);
526 * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
527 * 'mac-address' associated with given device.
529 * @dev: Device with which the mac-address cell is associated.
530 * @addrbuf: Buffer to which the MAC address will be copied on success.
532 * Returns 0 on success or a negative error number on failure.
534 int nvmem_get_mac_address(struct device *dev, void *addrbuf)
536 struct nvmem_cell *cell;
540 cell = nvmem_cell_get(dev, "mac-address");
542 return PTR_ERR(cell);
544 mac = nvmem_cell_read(cell, &len);
545 nvmem_cell_put(cell);
550 if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
555 ether_addr_copy(addrbuf, mac);
560 EXPORT_SYMBOL(nvmem_get_mac_address);