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>
54 #include <linux/property.h>
61 #include <net/flow_dissector.h>
63 #include <linux/uaccess.h>
64 #include <net/pkt_sched.h>
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, const void *data, u32 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 if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
169 if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
170 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
171 skb->pkt_type = PACKET_BROADCAST;
173 skb->pkt_type = PACKET_MULTICAST;
175 skb->pkt_type = PACKET_OTHERHOST;
180 * Some variants of DSA tagging don't have an ethertype field
181 * at all, so we check here whether one of those tagging
182 * variants has been configured on the receiving interface,
183 * and if so, set skb->protocol without looking at the packet.
185 if (unlikely(netdev_uses_dsa(dev)))
186 return htons(ETH_P_XDSA);
188 if (likely(eth_proto_is_802_3(eth->h_proto)))
192 * This is a magic hack to spot IPX packets. Older Novell breaks
193 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
194 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
195 * won't work for fault tolerant netware but does for the rest.
197 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
198 if (sap && *sap == 0xFFFF)
199 return htons(ETH_P_802_3);
204 return htons(ETH_P_802_2);
206 EXPORT_SYMBOL(eth_type_trans);
209 * eth_header_parse - extract hardware address from packet
210 * @skb: packet to extract header from
211 * @haddr: destination buffer
213 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
215 const struct ethhdr *eth = eth_hdr(skb);
216 memcpy(haddr, eth->h_source, ETH_ALEN);
219 EXPORT_SYMBOL(eth_header_parse);
222 * eth_header_cache - fill cache entry from neighbour
223 * @neigh: source neighbour
224 * @hh: destination cache entry
225 * @type: Ethernet type field
227 * Create an Ethernet header template from the neighbour.
229 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
232 const struct net_device *dev = neigh->dev;
234 eth = (struct ethhdr *)
235 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
237 if (type == htons(ETH_P_802_3))
241 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
242 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
244 /* Pairs with READ_ONCE() in neigh_resolve_output(),
245 * neigh_hh_output() and neigh_update_hhs().
247 smp_store_release(&hh->hh_len, ETH_HLEN);
251 EXPORT_SYMBOL(eth_header_cache);
254 * eth_header_cache_update - update cache entry
255 * @hh: destination cache entry
256 * @dev: network device
257 * @haddr: new hardware address
259 * Called by Address Resolution module to notify changes in address.
261 void eth_header_cache_update(struct hh_cache *hh,
262 const struct net_device *dev,
263 const unsigned char *haddr)
265 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
268 EXPORT_SYMBOL(eth_header_cache_update);
271 * eth_header_parse_protocol - extract protocol from L2 header
272 * @skb: packet to extract protocol from
274 __be16 eth_header_parse_protocol(const struct sk_buff *skb)
276 const struct ethhdr *eth = eth_hdr(skb);
280 EXPORT_SYMBOL(eth_header_parse_protocol);
283 * eth_prepare_mac_addr_change - prepare for mac change
284 * @dev: network device
287 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
289 struct sockaddr *addr = p;
291 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
293 if (!is_valid_ether_addr(addr->sa_data))
294 return -EADDRNOTAVAIL;
297 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
300 * eth_commit_mac_addr_change - commit mac change
301 * @dev: network device
304 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
306 struct sockaddr *addr = p;
308 eth_hw_addr_set(dev, addr->sa_data);
310 EXPORT_SYMBOL(eth_commit_mac_addr_change);
313 * eth_mac_addr - set new Ethernet hardware address
314 * @dev: network device
317 * Change hardware address of device.
319 * This doesn't change hardware matching, so needs to be overridden
320 * for most real devices.
322 int eth_mac_addr(struct net_device *dev, void *p)
326 ret = eth_prepare_mac_addr_change(dev, p);
329 eth_commit_mac_addr_change(dev, p);
332 EXPORT_SYMBOL(eth_mac_addr);
334 int eth_validate_addr(struct net_device *dev)
336 if (!is_valid_ether_addr(dev->dev_addr))
337 return -EADDRNOTAVAIL;
341 EXPORT_SYMBOL(eth_validate_addr);
343 const struct header_ops eth_header_ops ____cacheline_aligned = {
344 .create = eth_header,
345 .parse = eth_header_parse,
346 .cache = eth_header_cache,
347 .cache_update = eth_header_cache_update,
348 .parse_protocol = eth_header_parse_protocol,
352 * ether_setup - setup Ethernet network device
353 * @dev: network device
355 * Fill in the fields of the device structure with Ethernet-generic values.
357 void ether_setup(struct net_device *dev)
359 dev->header_ops = ð_header_ops;
360 dev->type = ARPHRD_ETHER;
361 dev->hard_header_len = ETH_HLEN;
362 dev->min_header_len = ETH_HLEN;
363 dev->mtu = ETH_DATA_LEN;
364 dev->min_mtu = ETH_MIN_MTU;
365 dev->max_mtu = ETH_DATA_LEN;
366 dev->addr_len = ETH_ALEN;
367 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
368 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
369 dev->priv_flags |= IFF_TX_SKB_SHARING;
371 eth_broadcast_addr(dev->broadcast);
374 EXPORT_SYMBOL(ether_setup);
377 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
378 * @sizeof_priv: Size of additional driver-private structure to be allocated
379 * for this Ethernet device
380 * @txqs: The number of TX queues this device has.
381 * @rxqs: The number of RX queues this device has.
383 * Fill in the fields of the device structure with Ethernet-generic
384 * values. Basically does everything except registering the device.
386 * Constructs a new net device, complete with a private data area of
387 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
388 * this private data area.
391 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
394 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_ENUM,
395 ether_setup, txqs, rxqs);
397 EXPORT_SYMBOL(alloc_etherdev_mqs);
399 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
401 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
403 EXPORT_SYMBOL(sysfs_format_mac);
405 struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
407 const struct packet_offload *ptype;
408 unsigned int hlen, off_eth;
409 struct sk_buff *pp = NULL;
410 struct ethhdr *eh, *eh2;
415 off_eth = skb_gro_offset(skb);
416 hlen = off_eth + sizeof(*eh);
417 eh = skb_gro_header(skb, hlen, off_eth);
423 list_for_each_entry(p, head, list) {
424 if (!NAPI_GRO_CB(p)->same_flow)
427 eh2 = (struct ethhdr *)(p->data + off_eth);
428 if (compare_ether_header(eh, eh2)) {
429 NAPI_GRO_CB(p)->same_flow = 0;
436 ptype = gro_find_receive_by_type(type);
442 skb_gro_pull(skb, sizeof(*eh));
443 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
445 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
446 ipv6_gro_receive, inet_gro_receive,
450 skb_gro_flush_final(skb, pp, flush);
454 EXPORT_SYMBOL(eth_gro_receive);
456 int eth_gro_complete(struct sk_buff *skb, int nhoff)
458 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
459 __be16 type = eh->h_proto;
460 struct packet_offload *ptype;
463 if (skb->encapsulation)
464 skb_set_inner_mac_header(skb, nhoff);
466 ptype = gro_find_complete_by_type(type);
468 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
469 ipv6_gro_complete, inet_gro_complete,
470 skb, nhoff + sizeof(*eh));
474 EXPORT_SYMBOL(eth_gro_complete);
476 static struct packet_offload eth_packet_offload __read_mostly = {
477 .type = cpu_to_be16(ETH_P_TEB),
480 .gro_receive = eth_gro_receive,
481 .gro_complete = eth_gro_complete,
485 static int __init eth_offload_init(void)
487 dev_add_offload(ð_packet_offload);
492 fs_initcall(eth_offload_init);
494 unsigned char * __weak arch_get_platform_mac_address(void)
499 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
504 ret = of_get_mac_address(dev->of_node, mac_addr);
508 addr = arch_get_platform_mac_address();
512 ether_addr_copy(mac_addr, addr);
516 EXPORT_SYMBOL(eth_platform_get_mac_address);
519 * platform_get_ethdev_address - Set netdev's MAC address from a given device
520 * @dev: Pointer to the device
521 * @netdev: Pointer to netdev to write the address to
523 * Wrapper around eth_platform_get_mac_address() which writes the address
524 * directly to netdev->dev_addr.
526 int platform_get_ethdev_address(struct device *dev, struct net_device *netdev)
528 u8 addr[ETH_ALEN] __aligned(2);
531 ret = eth_platform_get_mac_address(dev, addr);
533 eth_hw_addr_set(netdev, addr);
536 EXPORT_SYMBOL(platform_get_ethdev_address);
539 * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
540 * 'mac-address' associated with given device.
542 * @dev: Device with which the mac-address cell is associated.
543 * @addrbuf: Buffer to which the MAC address will be copied on success.
545 * Returns 0 on success or a negative error number on failure.
547 int nvmem_get_mac_address(struct device *dev, void *addrbuf)
549 struct nvmem_cell *cell;
553 cell = nvmem_cell_get(dev, "mac-address");
555 return PTR_ERR(cell);
557 mac = nvmem_cell_read(cell, &len);
558 nvmem_cell_put(cell);
563 if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
568 ether_addr_copy(addrbuf, mac);
574 static int fwnode_get_mac_addr(struct fwnode_handle *fwnode,
575 const char *name, char *addr)
579 ret = fwnode_property_read_u8_array(fwnode, name, addr, ETH_ALEN);
583 if (!is_valid_ether_addr(addr))
589 * fwnode_get_mac_address - Get the MAC from the firmware node
590 * @fwnode: Pointer to the firmware node
591 * @addr: Address of buffer to store the MAC in
593 * Search the firmware node for the best MAC address to use. 'mac-address' is
594 * checked first, because that is supposed to contain to "most recent" MAC
595 * address. If that isn't set, then 'local-mac-address' is checked next,
596 * because that is the default address. If that isn't set, then the obsolete
597 * 'address' is checked, just in case we're using an old device tree.
599 * Note that the 'address' property is supposed to contain a virtual address of
600 * the register set, but some DTS files have redefined that property to be the
603 * All-zero MAC addresses are rejected, because those could be properties that
604 * exist in the firmware tables, but were not updated by the firmware. For
605 * example, the DTS could define 'mac-address' and 'local-mac-address', with
606 * zero MAC addresses. Some older U-Boots only initialized 'local-mac-address'.
607 * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
608 * exists but is all zeros.
610 int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr)
612 if (!fwnode_get_mac_addr(fwnode, "mac-address", addr) ||
613 !fwnode_get_mac_addr(fwnode, "local-mac-address", addr) ||
614 !fwnode_get_mac_addr(fwnode, "address", addr))
619 EXPORT_SYMBOL(fwnode_get_mac_address);
622 * device_get_mac_address - Get the MAC for a given device
623 * @dev: Pointer to the device
624 * @addr: Address of buffer to store the MAC in
626 int device_get_mac_address(struct device *dev, char *addr)
628 return fwnode_get_mac_address(dev_fwnode(dev), addr);
630 EXPORT_SYMBOL(device_get_mac_address);
633 * device_get_ethdev_address - Set netdev's MAC address from a given device
634 * @dev: Pointer to the device
635 * @netdev: Pointer to netdev to write the address to
637 * Wrapper around device_get_mac_address() which writes the address
638 * directly to netdev->dev_addr.
640 int device_get_ethdev_address(struct device *dev, struct net_device *netdev)
645 ret = device_get_mac_address(dev, addr);
647 eth_hw_addr_set(netdev, addr);
650 EXPORT_SYMBOL(device_get_ethdev_address);