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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, <[email protected]>
13 * Mark Evans, <[email protected]>
14 * Florian La Roche, <[email protected]>
15 * Alan Cox, <[email protected]>
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(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(dev_net(dev), NULL, &keys, data,
137 eth->h_proto, sizeof(*eth),
138 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 const unsigned short *sap;
158 const struct ethhdr *eth;
159 __be16 res;
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 * We use skb->dev as temporary storage to not hit
185 * CONFIG_STACKPROTECTOR_STRONG=y costs on some platforms.
186 */
187 sap = skb_header_pointer(skb, 0, sizeof(*sap), &skb->dev);
188 res = (sap && *sap == 0xFFFF) ? htons(ETH_P_802_3) : htons(ETH_P_802_2);
189
190 /* restore skb->dev in case it was mangled by skb_header_pointer(). */
191 skb->dev = dev;
192 return res;
193}
194EXPORT_SYMBOL(eth_type_trans);
195
196int eth_header_parse(const struct sk_buff *skb, const struct net_device *dev,
197 unsigned char *haddr)
198{
199 const struct ethhdr *eth = eth_hdr(skb);
200
201 memcpy(haddr, eth->h_source, ETH_ALEN);
202 return ETH_ALEN;
203}
204EXPORT_SYMBOL(eth_header_parse);
205
206/**
207 * eth_header_cache - fill cache entry from neighbour
208 * @neigh: source neighbour
209 * @hh: destination cache entry
210 * @type: Ethernet type field
211 *
212 * Create an Ethernet header template from the neighbour.
213 */
214int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
215{
216 struct ethhdr *eth;
217 const struct net_device *dev = neigh->dev;
218
219 eth = (struct ethhdr *)
220 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
221
222 if (type == htons(ETH_P_802_3))
223 return -1;
224
225 eth->h_proto = type;
226 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
227 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
228
229 /* Pairs with READ_ONCE() in neigh_resolve_output(),
230 * neigh_hh_output() and neigh_update_hhs().
231 */
232 smp_store_release(&hh->hh_len, ETH_HLEN);
233
234 return 0;
235}
236EXPORT_SYMBOL(eth_header_cache);
237
238/**
239 * eth_header_cache_update - update cache entry
240 * @hh: destination cache entry
241 * @dev: network device
242 * @haddr: new hardware address
243 *
244 * Called by Address Resolution module to notify changes in address.
245 */
246void eth_header_cache_update(struct hh_cache *hh,
247 const struct net_device *dev,
248 const unsigned char *haddr)
249{
250 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
251 haddr, ETH_ALEN);
252}
253EXPORT_SYMBOL(eth_header_cache_update);
254
255/**
256 * eth_header_parse_protocol - extract protocol from L2 header
257 * @skb: packet to extract protocol from
258 */
259__be16 eth_header_parse_protocol(const struct sk_buff *skb)
260{
261 const struct ethhdr *eth = eth_hdr(skb);
262
263 return eth->h_proto;
264}
265EXPORT_SYMBOL(eth_header_parse_protocol);
266
267/**
268 * eth_prepare_mac_addr_change - prepare for mac change
269 * @dev: network device
270 * @p: socket address
271 */
272int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
273{
274 struct sockaddr *addr = p;
275
276 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
277 return -EBUSY;
278 if (!is_valid_ether_addr(addr->sa_data))
279 return -EADDRNOTAVAIL;
280 return 0;
281}
282EXPORT_SYMBOL(eth_prepare_mac_addr_change);
283
284/**
285 * eth_commit_mac_addr_change - commit mac change
286 * @dev: network device
287 * @p: socket address
288 */
289void eth_commit_mac_addr_change(struct net_device *dev, void *p)
290{
291 struct sockaddr *addr = p;
292
293 eth_hw_addr_set(dev, addr->sa_data);
294}
295EXPORT_SYMBOL(eth_commit_mac_addr_change);
296
297/**
298 * eth_mac_addr - set new Ethernet hardware address
299 * @dev: network device
300 * @p: socket address
301 *
302 * Change hardware address of device.
303 *
304 * This doesn't change hardware matching, so needs to be overridden
305 * for most real devices.
306 */
307int eth_mac_addr(struct net_device *dev, void *p)
308{
309 int ret;
310
311 ret = eth_prepare_mac_addr_change(dev, p);
312 if (ret < 0)
313 return ret;
314 eth_commit_mac_addr_change(dev, p);
315 return 0;
316}
317EXPORT_SYMBOL(eth_mac_addr);
318
319int eth_validate_addr(struct net_device *dev)
320{
321 if (!is_valid_ether_addr(dev->dev_addr))
322 return -EADDRNOTAVAIL;
323
324 return 0;
325}
326EXPORT_SYMBOL(eth_validate_addr);
327
328const struct header_ops eth_header_ops ____cacheline_aligned = {
329 .create = eth_header,
330 .parse = eth_header_parse,
331 .cache = eth_header_cache,
332 .cache_update = eth_header_cache_update,
333 .parse_protocol = eth_header_parse_protocol,
334};
335
336/**
337 * ether_setup - setup Ethernet network device
338 * @dev: network device
339 *
340 * Fill in the fields of the device structure with Ethernet-generic values.
341 */
342void ether_setup(struct net_device *dev)
343{
344 dev->header_ops = &eth_header_ops;
345 dev->type = ARPHRD_ETHER;
346 dev->hard_header_len = ETH_HLEN;
347 dev->min_header_len = ETH_HLEN;
348 dev->mtu = ETH_DATA_LEN;
349 dev->min_mtu = ETH_MIN_MTU;
350 dev->max_mtu = ETH_DATA_LEN;
351 dev->addr_len = ETH_ALEN;
352 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
353 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
354 dev->priv_flags |= IFF_TX_SKB_SHARING;
355
356 eth_broadcast_addr(dev->broadcast);
357
358}
359EXPORT_SYMBOL(ether_setup);
360
361/**
362 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
363 * @sizeof_priv: Size of additional driver-private structure to be allocated
364 * for this Ethernet device
365 * @txqs: The number of TX queues this device has.
366 * @rxqs: The number of RX queues this device has.
367 *
368 * Fill in the fields of the device structure with Ethernet-generic
369 * values. Basically does everything except registering the device.
370 *
371 * Constructs a new net device, complete with a private data area of
372 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
373 * this private data area.
374 */
375
376struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
377 unsigned int rxqs)
378{
379 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_ENUM,
380 ether_setup, txqs, rxqs);
381}
382EXPORT_SYMBOL(alloc_etherdev_mqs);
383
384ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
385{
386 return sysfs_emit(buf, "%*phC\n", len, addr);
387}
388EXPORT_SYMBOL(sysfs_format_mac);
389
390struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
391{
392 const struct packet_offload *ptype;
393 unsigned int hlen, off_eth;
394 struct sk_buff *pp = NULL;
395 struct ethhdr *eh, *eh2;
396 struct sk_buff *p;
397 __be16 type;
398 int flush = 1;
399
400 off_eth = skb_gro_offset(skb);
401 hlen = off_eth + sizeof(*eh);
402 eh = skb_gro_header(skb, hlen, off_eth);
403 if (unlikely(!eh))
404 goto out;
405
406 flush = 0;
407
408 list_for_each_entry(p, head, list) {
409 if (!NAPI_GRO_CB(p)->same_flow)
410 continue;
411
412 eh2 = (struct ethhdr *)(p->data + off_eth);
413 if (compare_ether_header(eh, eh2)) {
414 NAPI_GRO_CB(p)->same_flow = 0;
415 continue;
416 }
417 }
418
419 type = eh->h_proto;
420
421 ptype = gro_find_receive_by_type(type);
422 if (ptype == NULL) {
423 flush = 1;
424 goto out;
425 }
426
427 skb_gro_pull(skb, sizeof(*eh));
428 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
429
430 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
431 ipv6_gro_receive, inet_gro_receive,
432 head, skb);
433
434out:
435 skb_gro_flush_final(skb, pp, flush);
436
437 return pp;
438}
439EXPORT_SYMBOL(eth_gro_receive);
440
441int eth_gro_complete(struct sk_buff *skb, int nhoff)
442{
443 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
444 __be16 type = eh->h_proto;
445 struct packet_offload *ptype;
446 int err = -ENOSYS;
447
448 if (skb->encapsulation)
449 skb_set_inner_mac_header(skb, nhoff);
450
451 ptype = gro_find_complete_by_type(type);
452 if (ptype != NULL)
453 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
454 ipv6_gro_complete, inet_gro_complete,
455 skb, nhoff + sizeof(*eh));
456
457 return err;
458}
459EXPORT_SYMBOL(eth_gro_complete);
460
461static struct packet_offload eth_packet_offload __read_mostly = {
462 .type = cpu_to_be16(ETH_P_TEB),
463 .priority = 10,
464 .callbacks = {
465 .gro_receive = eth_gro_receive,
466 .gro_complete = eth_gro_complete,
467 },
468};
469
470static int __init eth_offload_init(void)
471{
472 dev_add_offload(&eth_packet_offload);
473
474 return 0;
475}
476
477fs_initcall(eth_offload_init);
478
479unsigned char * __weak arch_get_platform_mac_address(void)
480{
481 return NULL;
482}
483
484int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
485{
486 unsigned char *addr;
487 int ret;
488
489 ret = of_get_mac_address(dev->of_node, mac_addr);
490 if (!ret)
491 return 0;
492
493 addr = arch_get_platform_mac_address();
494 if (!addr)
495 return -ENODEV;
496
497 ether_addr_copy(mac_addr, addr);
498
499 return 0;
500}
501EXPORT_SYMBOL(eth_platform_get_mac_address);
502
503/**
504 * platform_get_ethdev_address - Set netdev's MAC address from a given device
505 * @dev: Pointer to the device
506 * @netdev: Pointer to netdev to write the address to
507 *
508 * Wrapper around eth_platform_get_mac_address() which writes the address
509 * directly to netdev->dev_addr.
510 */
511int platform_get_ethdev_address(struct device *dev, struct net_device *netdev)
512{
513 u8 addr[ETH_ALEN] __aligned(2);
514 int ret;
515
516 ret = eth_platform_get_mac_address(dev, addr);
517 if (!ret)
518 eth_hw_addr_set(netdev, addr);
519 return ret;
520}
521EXPORT_SYMBOL(platform_get_ethdev_address);
522
523/**
524 * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
525 * 'mac-address' associated with given device.
526 *
527 * @dev: Device with which the mac-address cell is associated.
528 * @addrbuf: Buffer to which the MAC address will be copied on success.
529 *
530 * Returns 0 on success or a negative error number on failure.
531 */
532int nvmem_get_mac_address(struct device *dev, void *addrbuf)
533{
534 struct nvmem_cell *cell;
535 const void *mac;
536 size_t len;
537
538 cell = nvmem_cell_get(dev, "mac-address");
539 if (IS_ERR(cell))
540 return PTR_ERR(cell);
541
542 mac = nvmem_cell_read(cell, &len);
543 nvmem_cell_put(cell);
544
545 if (IS_ERR(mac))
546 return PTR_ERR(mac);
547
548 if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
549 kfree(mac);
550 return -EINVAL;
551 }
552
553 ether_addr_copy(addrbuf, mac);
554 kfree(mac);
555
556 return 0;
557}
558
559static int fwnode_get_mac_addr(struct fwnode_handle *fwnode,
560 const char *name, char *addr)
561{
562 int ret;
563
564 ret = fwnode_property_read_u8_array(fwnode, name, addr, ETH_ALEN);
565 if (ret)
566 return ret;
567
568 if (!is_valid_ether_addr(addr))
569 return -EINVAL;
570 return 0;
571}
572
573/**
574 * fwnode_get_mac_address - Get the MAC from the firmware node
575 * @fwnode: Pointer to the firmware node
576 * @addr: Address of buffer to store the MAC in
577 *
578 * Search the firmware node for the best MAC address to use. 'mac-address' is
579 * checked first, because that is supposed to contain to "most recent" MAC
580 * address. If that isn't set, then 'local-mac-address' is checked next,
581 * because that is the default address. If that isn't set, then the obsolete
582 * 'address' is checked, just in case we're using an old device tree.
583 *
584 * Note that the 'address' property is supposed to contain a virtual address of
585 * the register set, but some DTS files have redefined that property to be the
586 * MAC address.
587 *
588 * All-zero MAC addresses are rejected, because those could be properties that
589 * exist in the firmware tables, but were not updated by the firmware. For
590 * example, the DTS could define 'mac-address' and 'local-mac-address', with
591 * zero MAC addresses. Some older U-Boots only initialized 'local-mac-address'.
592 * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
593 * exists but is all zeros.
594 */
595int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr)
596{
597 if (!fwnode_get_mac_addr(fwnode, "mac-address", addr) ||
598 !fwnode_get_mac_addr(fwnode, "local-mac-address", addr) ||
599 !fwnode_get_mac_addr(fwnode, "address", addr))
600 return 0;
601
602 return -ENOENT;
603}
604EXPORT_SYMBOL(fwnode_get_mac_address);
605
606/**
607 * device_get_mac_address - Get the MAC for a given device
608 * @dev: Pointer to the device
609 * @addr: Address of buffer to store the MAC in
610 */
611int device_get_mac_address(struct device *dev, char *addr)
612{
613 if (!fwnode_get_mac_address(dev_fwnode(dev), addr))
614 return 0;
615
616 return nvmem_get_mac_address(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(netdev, addr);
636 return ret;
637}
638EXPORT_SYMBOL(device_get_ethdev_address);