1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
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.
6 *
7 * Ethernet-type device handling.
8 *
9 * Version: @(#)eth.c 1.0.7 05/25/93
10 *
11 * Authors: Ross Biro
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>
16 *
17 * Fixes:
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
22 * minor other things.
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().
35 */
36#include <linux/module.h>
37#include <linux/types.h>
38#include <linux/kernel.h>
39#include <linux/string.h>
40#include <linux/mm.h>
41#include <linux/socket.h>
42#include <linux/in.h>
43#include <linux/inet.h>
44#include <linux/ip.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>
55#include <net/dst.h>
56#include <net/arp.h>
57#include <net/sock.h>
58#include <net/ipv6.h>
59#include <net/ip.h>
60#include <net/dsa.h>
61#include <net/flow_dissector.h>
62#include <net/gro.h>
63#include <linux/uaccess.h>
64#include <net/pkt_sched.h>
65
66/**
67 * eth_header - create the Ethernet header
68 * @skb: buffer to alter
69 * @dev: source device
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)
74 *
75 *
76 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
77 * in here instead.
78 */
79int eth_header(struct sk_buff *skb, struct net_device *dev,
80 unsigned short type,
81 const void *daddr, const void *saddr, unsigned int len)
82{
83 struct ethhdr *eth = skb_push(skb, ETH_HLEN);
84
85 if (type != ETH_P_802_3 && type != ETH_P_802_2)
86 eth->h_proto = htons(type);
87 else
88 eth->h_proto = htons(len);
89
90 /*
91 * Set the source hardware address.
92 */
93
94 if (!saddr)
95 saddr = dev->dev_addr;
96 memcpy(eth->h_source, saddr, ETH_ALEN);
97
98 if (daddr) {
99 memcpy(eth->h_dest, daddr, ETH_ALEN);
100 return ETH_HLEN;
101 }
102
103 /*
104 * Anyway, the loopback-device should never use this function...
105 */
106
107 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
108 eth_zero_addr(addr: eth->h_dest);
109 return ETH_HLEN;
110 }
111
112 return -ETH_HLEN;
113}
114EXPORT_SYMBOL(eth_header);
115
116/**
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
121 *
122 * Make a best effort attempt to pull the length for all of the headers for
123 * a given frame in a linear buffer.
124 */
125u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len)
126{
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;
130
131 /* this should never happen, but better safe than sorry */
132 if (unlikely(len < sizeof(*eth)))
133 return len;
134
135 /* parse any remaining L2/L3 headers, check for L4 */
136 if (!skb_flow_dissect_flow_keys_basic(net: dev_net(dev), NULL, flow: &keys, data,
137 proto: eth->h_proto, nhoff: sizeof(*eth),
138 hlen: len, flags))
139 return max_t(u32, keys.control.thoff, sizeof(*eth));
140
141 /* parse for any L4 headers */
142 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
143}
144EXPORT_SYMBOL(eth_get_headlen);
145
146/**
147 * eth_type_trans - determine the packet's protocol ID.
148 * @skb: received socket data
149 * @dev: receiving network device
150 *
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.
154 */
155__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
156{
157 unsigned short _service_access_point;
158 const unsigned short *sap;
159 const struct ethhdr *eth;
160
161 skb->dev = dev;
162 skb_reset_mac_header(skb);
163
164 eth = eth_skb_pull_mac(skb);
165 eth_skb_pkt_type(skb, dev);
166
167 /*
168 * Some variants of DSA tagging don't have an ethertype field
169 * at all, so we check here whether one of those tagging
170 * variants has been configured on the receiving interface,
171 * and if so, set skb->protocol without looking at the packet.
172 */
173 if (unlikely(netdev_uses_dsa(dev)))
174 return htons(ETH_P_XDSA);
175
176 if (likely(eth_proto_is_802_3(eth->h_proto)))
177 return eth->h_proto;
178
179 /*
180 * This is a magic hack to spot IPX packets. Older Novell breaks
181 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
182 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
183 * won't work for fault tolerant netware but does for the rest.
184 */
185 sap = skb_header_pointer(skb, offset: 0, len: sizeof(*sap), buffer: &_service_access_point);
186 if (sap && *sap == 0xFFFF)
187 return htons(ETH_P_802_3);
188
189 /*
190 * Real 802.2 LLC
191 */
192 return htons(ETH_P_802_2);
193}
194EXPORT_SYMBOL(eth_type_trans);
195
196/**
197 * eth_header_parse - extract hardware address from packet
198 * @skb: packet to extract header from
199 * @haddr: destination buffer
200 */
201int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
202{
203 const struct ethhdr *eth = eth_hdr(skb);
204 memcpy(haddr, eth->h_source, ETH_ALEN);
205 return ETH_ALEN;
206}
207EXPORT_SYMBOL(eth_header_parse);
208
209/**
210 * eth_header_cache - fill cache entry from neighbour
211 * @neigh: source neighbour
212 * @hh: destination cache entry
213 * @type: Ethernet type field
214 *
215 * Create an Ethernet header template from the neighbour.
216 */
217int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
218{
219 struct ethhdr *eth;
220 const struct net_device *dev = neigh->dev;
221
222 eth = (struct ethhdr *)
223 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
224
225 if (type == htons(ETH_P_802_3))
226 return -1;
227
228 eth->h_proto = type;
229 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
230 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
231
232 /* Pairs with READ_ONCE() in neigh_resolve_output(),
233 * neigh_hh_output() and neigh_update_hhs().
234 */
235 smp_store_release(&hh->hh_len, ETH_HLEN);
236
237 return 0;
238}
239EXPORT_SYMBOL(eth_header_cache);
240
241/**
242 * eth_header_cache_update - update cache entry
243 * @hh: destination cache entry
244 * @dev: network device
245 * @haddr: new hardware address
246 *
247 * Called by Address Resolution module to notify changes in address.
248 */
249void eth_header_cache_update(struct hh_cache *hh,
250 const struct net_device *dev,
251 const unsigned char *haddr)
252{
253 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
254 haddr, ETH_ALEN);
255}
256EXPORT_SYMBOL(eth_header_cache_update);
257
258/**
259 * eth_header_parse_protocol - extract protocol from L2 header
260 * @skb: packet to extract protocol from
261 */
262__be16 eth_header_parse_protocol(const struct sk_buff *skb)
263{
264 const struct ethhdr *eth = eth_hdr(skb);
265
266 return eth->h_proto;
267}
268EXPORT_SYMBOL(eth_header_parse_protocol);
269
270/**
271 * eth_prepare_mac_addr_change - prepare for mac change
272 * @dev: network device
273 * @p: socket address
274 */
275int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
276{
277 struct sockaddr *addr = p;
278
279 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
280 return -EBUSY;
281 if (!is_valid_ether_addr(addr: addr->sa_data))
282 return -EADDRNOTAVAIL;
283 return 0;
284}
285EXPORT_SYMBOL(eth_prepare_mac_addr_change);
286
287/**
288 * eth_commit_mac_addr_change - commit mac change
289 * @dev: network device
290 * @p: socket address
291 */
292void eth_commit_mac_addr_change(struct net_device *dev, void *p)
293{
294 struct sockaddr *addr = p;
295
296 eth_hw_addr_set(dev, addr: addr->sa_data);
297}
298EXPORT_SYMBOL(eth_commit_mac_addr_change);
299
300/**
301 * eth_mac_addr - set new Ethernet hardware address
302 * @dev: network device
303 * @p: socket address
304 *
305 * Change hardware address of device.
306 *
307 * This doesn't change hardware matching, so needs to be overridden
308 * for most real devices.
309 */
310int eth_mac_addr(struct net_device *dev, void *p)
311{
312 int ret;
313
314 ret = eth_prepare_mac_addr_change(dev, p);
315 if (ret < 0)
316 return ret;
317 eth_commit_mac_addr_change(dev, p);
318 return 0;
319}
320EXPORT_SYMBOL(eth_mac_addr);
321
322int eth_validate_addr(struct net_device *dev)
323{
324 if (!is_valid_ether_addr(addr: dev->dev_addr))
325 return -EADDRNOTAVAIL;
326
327 return 0;
328}
329EXPORT_SYMBOL(eth_validate_addr);
330
331const struct header_ops eth_header_ops ____cacheline_aligned = {
332 .create = eth_header,
333 .parse = eth_header_parse,
334 .cache = eth_header_cache,
335 .cache_update = eth_header_cache_update,
336 .parse_protocol = eth_header_parse_protocol,
337};
338
339/**
340 * ether_setup - setup Ethernet network device
341 * @dev: network device
342 *
343 * Fill in the fields of the device structure with Ethernet-generic values.
344 */
345void ether_setup(struct net_device *dev)
346{
347 dev->header_ops = &eth_header_ops;
348 dev->type = ARPHRD_ETHER;
349 dev->hard_header_len = ETH_HLEN;
350 dev->min_header_len = ETH_HLEN;
351 dev->mtu = ETH_DATA_LEN;
352 dev->min_mtu = ETH_MIN_MTU;
353 dev->max_mtu = ETH_DATA_LEN;
354 dev->addr_len = ETH_ALEN;
355 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
356 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
357 dev->priv_flags |= IFF_TX_SKB_SHARING;
358
359 eth_broadcast_addr(addr: dev->broadcast);
360
361}
362EXPORT_SYMBOL(ether_setup);
363
364/**
365 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
366 * @sizeof_priv: Size of additional driver-private structure to be allocated
367 * for this Ethernet device
368 * @txqs: The number of TX queues this device has.
369 * @rxqs: The number of RX queues this device has.
370 *
371 * Fill in the fields of the device structure with Ethernet-generic
372 * values. Basically does everything except registering the device.
373 *
374 * Constructs a new net device, complete with a private data area of
375 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
376 * this private data area.
377 */
378
379struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
380 unsigned int rxqs)
381{
382 return alloc_netdev_mqs(sizeof_priv, name: "eth%d", NET_NAME_ENUM,
383 setup: ether_setup, txqs, rxqs);
384}
385EXPORT_SYMBOL(alloc_etherdev_mqs);
386
387ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
388{
389 return sysfs_emit(buf, fmt: "%*phC\n", len, addr);
390}
391EXPORT_SYMBOL(sysfs_format_mac);
392
393struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
394{
395 const struct packet_offload *ptype;
396 unsigned int hlen, off_eth;
397 struct sk_buff *pp = NULL;
398 struct ethhdr *eh, *eh2;
399 struct sk_buff *p;
400 __be16 type;
401 int flush = 1;
402
403 off_eth = skb_gro_offset(skb);
404 hlen = off_eth + sizeof(*eh);
405 eh = skb_gro_header(skb, hlen, offset: off_eth);
406 if (unlikely(!eh))
407 goto out;
408
409 flush = 0;
410
411 list_for_each_entry(p, head, list) {
412 if (!NAPI_GRO_CB(p)->same_flow)
413 continue;
414
415 eh2 = (struct ethhdr *)(p->data + off_eth);
416 if (compare_ether_header(a: eh, b: eh2)) {
417 NAPI_GRO_CB(p)->same_flow = 0;
418 continue;
419 }
420 }
421
422 type = eh->h_proto;
423
424 ptype = gro_find_receive_by_type(type);
425 if (ptype == NULL) {
426 flush = 1;
427 goto out;
428 }
429
430 skb_gro_pull(skb, len: sizeof(*eh));
431 skb_gro_postpull_rcsum(skb, start: eh, len: sizeof(*eh));
432
433 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
434 ipv6_gro_receive, inet_gro_receive,
435 head, skb);
436
437out:
438 skb_gro_flush_final(skb, pp, flush);
439
440 return pp;
441}
442EXPORT_SYMBOL(eth_gro_receive);
443
444int eth_gro_complete(struct sk_buff *skb, int nhoff)
445{
446 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
447 __be16 type = eh->h_proto;
448 struct packet_offload *ptype;
449 int err = -ENOSYS;
450
451 if (skb->encapsulation)
452 skb_set_inner_mac_header(skb, offset: nhoff);
453
454 ptype = gro_find_complete_by_type(type);
455 if (ptype != NULL)
456 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
457 ipv6_gro_complete, inet_gro_complete,
458 skb, nhoff + sizeof(*eh));
459
460 return err;
461}
462EXPORT_SYMBOL(eth_gro_complete);
463
464static struct packet_offload eth_packet_offload __read_mostly = {
465 .type = cpu_to_be16(ETH_P_TEB),
466 .priority = 10,
467 .callbacks = {
468 .gro_receive = eth_gro_receive,
469 .gro_complete = eth_gro_complete,
470 },
471};
472
473static int __init eth_offload_init(void)
474{
475 dev_add_offload(po: &eth_packet_offload);
476
477 return 0;
478}
479
480fs_initcall(eth_offload_init);
481
482unsigned char * __weak arch_get_platform_mac_address(void)
483{
484 return NULL;
485}
486
487int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
488{
489 unsigned char *addr;
490 int ret;
491
492 ret = of_get_mac_address(np: dev->of_node, mac: mac_addr);
493 if (!ret)
494 return 0;
495
496 addr = arch_get_platform_mac_address();
497 if (!addr)
498 return -ENODEV;
499
500 ether_addr_copy(dst: mac_addr, src: addr);
501
502 return 0;
503}
504EXPORT_SYMBOL(eth_platform_get_mac_address);
505
506/**
507 * platform_get_ethdev_address - Set netdev's MAC address from a given device
508 * @dev: Pointer to the device
509 * @netdev: Pointer to netdev to write the address to
510 *
511 * Wrapper around eth_platform_get_mac_address() which writes the address
512 * directly to netdev->dev_addr.
513 */
514int platform_get_ethdev_address(struct device *dev, struct net_device *netdev)
515{
516 u8 addr[ETH_ALEN] __aligned(2);
517 int ret;
518
519 ret = eth_platform_get_mac_address(dev, addr);
520 if (!ret)
521 eth_hw_addr_set(dev: netdev, addr);
522 return ret;
523}
524EXPORT_SYMBOL(platform_get_ethdev_address);
525
526/**
527 * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
528 * 'mac-address' associated with given device.
529 *
530 * @dev: Device with which the mac-address cell is associated.
531 * @addrbuf: Buffer to which the MAC address will be copied on success.
532 *
533 * Returns 0 on success or a negative error number on failure.
534 */
535int nvmem_get_mac_address(struct device *dev, void *addrbuf)
536{
537 struct nvmem_cell *cell;
538 const void *mac;
539 size_t len;
540
541 cell = nvmem_cell_get(dev, id: "mac-address");
542 if (IS_ERR(ptr: cell))
543 return PTR_ERR(ptr: cell);
544
545 mac = nvmem_cell_read(cell, len: &len);
546 nvmem_cell_put(cell);
547
548 if (IS_ERR(ptr: mac))
549 return PTR_ERR(ptr: mac);
550
551 if (len != ETH_ALEN || !is_valid_ether_addr(addr: mac)) {
552 kfree(objp: mac);
553 return -EINVAL;
554 }
555
556 ether_addr_copy(dst: addrbuf, src: mac);
557 kfree(objp: mac);
558
559 return 0;
560}
561
562static int fwnode_get_mac_addr(struct fwnode_handle *fwnode,
563 const char *name, char *addr)
564{
565 int ret;
566
567 ret = fwnode_property_read_u8_array(fwnode, propname: name, val: addr, ETH_ALEN);
568 if (ret)
569 return ret;
570
571 if (!is_valid_ether_addr(addr))
572 return -EINVAL;
573 return 0;
574}
575
576/**
577 * fwnode_get_mac_address - Get the MAC from the firmware node
578 * @fwnode: Pointer to the firmware node
579 * @addr: Address of buffer to store the MAC in
580 *
581 * Search the firmware node for the best MAC address to use. 'mac-address' is
582 * checked first, because that is supposed to contain to "most recent" MAC
583 * address. If that isn't set, then 'local-mac-address' is checked next,
584 * because that is the default address. If that isn't set, then the obsolete
585 * 'address' is checked, just in case we're using an old device tree.
586 *
587 * Note that the 'address' property is supposed to contain a virtual address of
588 * the register set, but some DTS files have redefined that property to be the
589 * MAC address.
590 *
591 * All-zero MAC addresses are rejected, because those could be properties that
592 * exist in the firmware tables, but were not updated by the firmware. For
593 * example, the DTS could define 'mac-address' and 'local-mac-address', with
594 * zero MAC addresses. Some older U-Boots only initialized 'local-mac-address'.
595 * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
596 * exists but is all zeros.
597 */
598int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr)
599{
600 if (!fwnode_get_mac_addr(fwnode, name: "mac-address", addr) ||
601 !fwnode_get_mac_addr(fwnode, name: "local-mac-address", addr) ||
602 !fwnode_get_mac_addr(fwnode, name: "address", addr))
603 return 0;
604
605 return -ENOENT;
606}
607EXPORT_SYMBOL(fwnode_get_mac_address);
608
609/**
610 * device_get_mac_address - Get the MAC for a given device
611 * @dev: Pointer to the device
612 * @addr: Address of buffer to store the MAC in
613 */
614int device_get_mac_address(struct device *dev, char *addr)
615{
616 return fwnode_get_mac_address(dev_fwnode(dev), addr);
617}
618EXPORT_SYMBOL(device_get_mac_address);
619
620/**
621 * device_get_ethdev_address - Set netdev's MAC address from a given device
622 * @dev: Pointer to the device
623 * @netdev: Pointer to netdev to write the address to
624 *
625 * Wrapper around device_get_mac_address() which writes the address
626 * directly to netdev->dev_addr.
627 */
628int device_get_ethdev_address(struct device *dev, struct net_device *netdev)
629{
630 u8 addr[ETH_ALEN];
631 int ret;
632
633 ret = device_get_mac_address(dev, addr);
634 if (!ret)
635 eth_hw_addr_set(dev: netdev, addr);
636 return ret;
637}
638EXPORT_SYMBOL(device_get_ethdev_address);
639

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source code of linux/net/ethernet/eth.c