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 */
eth_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,const void * daddr,const void * saddr,unsigned int len)79 int 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 }
114 EXPORT_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 */
eth_get_headlen(const struct net_device * dev,const void * data,u32 len)125 u32 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 }
144 EXPORT_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 */
eth_type_trans(struct sk_buff * skb,struct net_device * dev)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 = (struct ethhdr *)skb->data;
165 skb_pull_inline(skb, ETH_HLEN);
166
167 eth_skb_pkt_type(skb, dev);
168
169 /*
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 */
175 if (unlikely(netdev_uses_dsa(dev)))
176 return htons(ETH_P_XDSA);
177
178 if (likely(eth_proto_is_802_3(eth->h_proto)))
179 return eth->h_proto;
180
181 /*
182 * This is a magic hack to spot IPX packets. Older Novell breaks
183 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
184 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
185 * won't work for fault tolerant netware but does for the rest.
186 */
187 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
188 if (sap && *sap == 0xFFFF)
189 return htons(ETH_P_802_3);
190
191 /*
192 * Real 802.2 LLC
193 */
194 return htons(ETH_P_802_2);
195 }
196 EXPORT_SYMBOL(eth_type_trans);
197
198 /**
199 * eth_header_parse - extract hardware address from packet
200 * @skb: packet to extract header from
201 * @haddr: destination buffer
202 */
eth_header_parse(const struct sk_buff * skb,unsigned char * haddr)203 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
204 {
205 const struct ethhdr *eth = eth_hdr(skb);
206 memcpy(haddr, eth->h_source, ETH_ALEN);
207 return ETH_ALEN;
208 }
209 EXPORT_SYMBOL(eth_header_parse);
210
211 /**
212 * eth_header_cache - fill cache entry from neighbour
213 * @neigh: source neighbour
214 * @hh: destination cache entry
215 * @type: Ethernet type field
216 *
217 * Create an Ethernet header template from the neighbour.
218 */
eth_header_cache(const struct neighbour * neigh,struct hh_cache * hh,__be16 type)219 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
220 {
221 struct ethhdr *eth;
222 const struct net_device *dev = neigh->dev;
223
224 eth = (struct ethhdr *)
225 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
226
227 if (type == htons(ETH_P_802_3))
228 return -1;
229
230 eth->h_proto = type;
231 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
232 memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
233
234 /* Pairs with READ_ONCE() in neigh_resolve_output(),
235 * neigh_hh_output() and neigh_update_hhs().
236 */
237 smp_store_release(&hh->hh_len, ETH_HLEN);
238
239 return 0;
240 }
241 EXPORT_SYMBOL(eth_header_cache);
242
243 /**
244 * eth_header_cache_update - update cache entry
245 * @hh: destination cache entry
246 * @dev: network device
247 * @haddr: new hardware address
248 *
249 * Called by Address Resolution module to notify changes in address.
250 */
eth_header_cache_update(struct hh_cache * hh,const struct net_device * dev,const unsigned char * haddr)251 void eth_header_cache_update(struct hh_cache *hh,
252 const struct net_device *dev,
253 const unsigned char *haddr)
254 {
255 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
256 haddr, ETH_ALEN);
257 }
258 EXPORT_SYMBOL(eth_header_cache_update);
259
260 /**
261 * eth_header_parse_protocol - extract protocol from L2 header
262 * @skb: packet to extract protocol from
263 */
eth_header_parse_protocol(const struct sk_buff * skb)264 __be16 eth_header_parse_protocol(const struct sk_buff *skb)
265 {
266 const struct ethhdr *eth = eth_hdr(skb);
267
268 return eth->h_proto;
269 }
270 EXPORT_SYMBOL(eth_header_parse_protocol);
271
272 /**
273 * eth_prepare_mac_addr_change - prepare for mac change
274 * @dev: network device
275 * @p: socket address
276 */
eth_prepare_mac_addr_change(struct net_device * dev,void * p)277 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
278 {
279 struct sockaddr *addr = p;
280
281 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
282 return -EBUSY;
283 if (!is_valid_ether_addr(addr->sa_data))
284 return -EADDRNOTAVAIL;
285 return 0;
286 }
287 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
288
289 /**
290 * eth_commit_mac_addr_change - commit mac change
291 * @dev: network device
292 * @p: socket address
293 */
eth_commit_mac_addr_change(struct net_device * dev,void * p)294 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
295 {
296 struct sockaddr *addr = p;
297
298 eth_hw_addr_set(dev, addr->sa_data);
299 }
300 EXPORT_SYMBOL(eth_commit_mac_addr_change);
301
302 /**
303 * eth_mac_addr - set new Ethernet hardware address
304 * @dev: network device
305 * @p: socket address
306 *
307 * Change hardware address of device.
308 *
309 * This doesn't change hardware matching, so needs to be overridden
310 * for most real devices.
311 */
eth_mac_addr(struct net_device * dev,void * p)312 int eth_mac_addr(struct net_device *dev, void *p)
313 {
314 int ret;
315
316 ret = eth_prepare_mac_addr_change(dev, p);
317 if (ret < 0)
318 return ret;
319 eth_commit_mac_addr_change(dev, p);
320 return 0;
321 }
322 EXPORT_SYMBOL(eth_mac_addr);
323
eth_validate_addr(struct net_device * dev)324 int eth_validate_addr(struct net_device *dev)
325 {
326 if (!is_valid_ether_addr(dev->dev_addr))
327 return -EADDRNOTAVAIL;
328
329 return 0;
330 }
331 EXPORT_SYMBOL(eth_validate_addr);
332
333 const struct header_ops eth_header_ops ____cacheline_aligned = {
334 .create = eth_header,
335 .parse = eth_header_parse,
336 .cache = eth_header_cache,
337 .cache_update = eth_header_cache_update,
338 .parse_protocol = eth_header_parse_protocol,
339 };
340
341 /**
342 * ether_setup - setup Ethernet network device
343 * @dev: network device
344 *
345 * Fill in the fields of the device structure with Ethernet-generic values.
346 */
ether_setup(struct net_device * dev)347 void ether_setup(struct net_device *dev)
348 {
349 dev->header_ops = ð_header_ops;
350 dev->type = ARPHRD_ETHER;
351 dev->hard_header_len = ETH_HLEN;
352 dev->min_header_len = ETH_HLEN;
353 dev->mtu = ETH_DATA_LEN;
354 dev->min_mtu = ETH_MIN_MTU;
355 dev->max_mtu = ETH_DATA_LEN;
356 dev->addr_len = ETH_ALEN;
357 dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
358 dev->flags = IFF_BROADCAST|IFF_MULTICAST;
359 dev->priv_flags |= IFF_TX_SKB_SHARING;
360
361 eth_broadcast_addr(dev->broadcast);
362
363 }
364 EXPORT_SYMBOL(ether_setup);
365
366 /**
367 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
368 * @sizeof_priv: Size of additional driver-private structure to be allocated
369 * for this Ethernet device
370 * @txqs: The number of TX queues this device has.
371 * @rxqs: The number of RX queues this device has.
372 *
373 * Fill in the fields of the device structure with Ethernet-generic
374 * values. Basically does everything except registering the device.
375 *
376 * Constructs a new net device, complete with a private data area of
377 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
378 * this private data area.
379 */
380
alloc_etherdev_mqs(int sizeof_priv,unsigned int txqs,unsigned int rxqs)381 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
382 unsigned int rxqs)
383 {
384 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_ENUM,
385 ether_setup, txqs, rxqs);
386 }
387 EXPORT_SYMBOL(alloc_etherdev_mqs);
388
sysfs_format_mac(char * buf,const unsigned char * addr,int len)389 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
390 {
391 return sysfs_emit(buf, "%*phC\n", len, addr);
392 }
393 EXPORT_SYMBOL(sysfs_format_mac);
394
eth_gro_receive(struct list_head * head,struct sk_buff * skb)395 struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
396 {
397 const struct packet_offload *ptype;
398 unsigned int hlen, off_eth;
399 struct sk_buff *pp = NULL;
400 struct ethhdr *eh, *eh2;
401 struct sk_buff *p;
402 __be16 type;
403 int flush = 1;
404
405 off_eth = skb_gro_offset(skb);
406 hlen = off_eth + sizeof(*eh);
407 eh = skb_gro_header(skb, hlen, off_eth);
408 if (unlikely(!eh))
409 goto out;
410
411 flush = 0;
412
413 list_for_each_entry(p, head, list) {
414 if (!NAPI_GRO_CB(p)->same_flow)
415 continue;
416
417 eh2 = (struct ethhdr *)(p->data + off_eth);
418 if (compare_ether_header(eh, eh2)) {
419 NAPI_GRO_CB(p)->same_flow = 0;
420 continue;
421 }
422 }
423
424 type = eh->h_proto;
425
426 ptype = gro_find_receive_by_type(type);
427 if (ptype == NULL) {
428 flush = 1;
429 goto out;
430 }
431
432 skb_gro_pull(skb, sizeof(*eh));
433 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
434
435 pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
436 ipv6_gro_receive, inet_gro_receive,
437 head, skb);
438
439 out:
440 skb_gro_flush_final(skb, pp, flush);
441
442 return pp;
443 }
444 EXPORT_SYMBOL(eth_gro_receive);
445
eth_gro_complete(struct sk_buff * skb,int nhoff)446 int eth_gro_complete(struct sk_buff *skb, int nhoff)
447 {
448 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
449 __be16 type = eh->h_proto;
450 struct packet_offload *ptype;
451 int err = -ENOSYS;
452
453 if (skb->encapsulation)
454 skb_set_inner_mac_header(skb, nhoff);
455
456 ptype = gro_find_complete_by_type(type);
457 if (ptype != NULL)
458 err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
459 ipv6_gro_complete, inet_gro_complete,
460 skb, nhoff + sizeof(*eh));
461
462 return err;
463 }
464 EXPORT_SYMBOL(eth_gro_complete);
465
466 static struct packet_offload eth_packet_offload __read_mostly = {
467 .type = cpu_to_be16(ETH_P_TEB),
468 .priority = 10,
469 .callbacks = {
470 .gro_receive = eth_gro_receive,
471 .gro_complete = eth_gro_complete,
472 },
473 };
474
eth_offload_init(void)475 static int __init eth_offload_init(void)
476 {
477 dev_add_offload(ð_packet_offload);
478
479 return 0;
480 }
481
482 fs_initcall(eth_offload_init);
483
arch_get_platform_mac_address(void)484 unsigned char * __weak arch_get_platform_mac_address(void)
485 {
486 return NULL;
487 }
488
eth_platform_get_mac_address(struct device * dev,u8 * mac_addr)489 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
490 {
491 unsigned char *addr;
492 int ret;
493
494 ret = of_get_mac_address(dev->of_node, mac_addr);
495 if (!ret)
496 return 0;
497
498 addr = arch_get_platform_mac_address();
499 if (!addr)
500 return -ENODEV;
501
502 ether_addr_copy(mac_addr, addr);
503
504 return 0;
505 }
506 EXPORT_SYMBOL(eth_platform_get_mac_address);
507
508 /**
509 * platform_get_ethdev_address - Set netdev's MAC address from a given device
510 * @dev: Pointer to the device
511 * @netdev: Pointer to netdev to write the address to
512 *
513 * Wrapper around eth_platform_get_mac_address() which writes the address
514 * directly to netdev->dev_addr.
515 */
platform_get_ethdev_address(struct device * dev,struct net_device * netdev)516 int platform_get_ethdev_address(struct device *dev, struct net_device *netdev)
517 {
518 u8 addr[ETH_ALEN] __aligned(2);
519 int ret;
520
521 ret = eth_platform_get_mac_address(dev, addr);
522 if (!ret)
523 eth_hw_addr_set(netdev, addr);
524 return ret;
525 }
526 EXPORT_SYMBOL(platform_get_ethdev_address);
527
528 /**
529 * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
530 * 'mac-address' associated with given device.
531 *
532 * @dev: Device with which the mac-address cell is associated.
533 * @addrbuf: Buffer to which the MAC address will be copied on success.
534 *
535 * Returns 0 on success or a negative error number on failure.
536 */
nvmem_get_mac_address(struct device * dev,void * addrbuf)537 int nvmem_get_mac_address(struct device *dev, void *addrbuf)
538 {
539 struct nvmem_cell *cell;
540 const void *mac;
541 size_t len;
542
543 cell = nvmem_cell_get(dev, "mac-address");
544 if (IS_ERR(cell))
545 return PTR_ERR(cell);
546
547 mac = nvmem_cell_read(cell, &len);
548 nvmem_cell_put(cell);
549
550 if (IS_ERR(mac))
551 return PTR_ERR(mac);
552
553 if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
554 kfree(mac);
555 return -EINVAL;
556 }
557
558 ether_addr_copy(addrbuf, mac);
559 kfree(mac);
560
561 return 0;
562 }
563
fwnode_get_mac_addr(struct fwnode_handle * fwnode,const char * name,char * addr)564 static int fwnode_get_mac_addr(struct fwnode_handle *fwnode,
565 const char *name, char *addr)
566 {
567 int ret;
568
569 ret = fwnode_property_read_u8_array(fwnode, name, addr, ETH_ALEN);
570 if (ret)
571 return ret;
572
573 if (!is_valid_ether_addr(addr))
574 return -EINVAL;
575 return 0;
576 }
577
578 /**
579 * fwnode_get_mac_address - Get the MAC from the firmware node
580 * @fwnode: Pointer to the firmware node
581 * @addr: Address of buffer to store the MAC in
582 *
583 * Search the firmware node for the best MAC address to use. 'mac-address' is
584 * checked first, because that is supposed to contain to "most recent" MAC
585 * address. If that isn't set, then 'local-mac-address' is checked next,
586 * because that is the default address. If that isn't set, then the obsolete
587 * 'address' is checked, just in case we're using an old device tree.
588 *
589 * Note that the 'address' property is supposed to contain a virtual address of
590 * the register set, but some DTS files have redefined that property to be the
591 * MAC address.
592 *
593 * All-zero MAC addresses are rejected, because those could be properties that
594 * exist in the firmware tables, but were not updated by the firmware. For
595 * example, the DTS could define 'mac-address' and 'local-mac-address', with
596 * zero MAC addresses. Some older U-Boots only initialized 'local-mac-address'.
597 * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
598 * exists but is all zeros.
599 */
fwnode_get_mac_address(struct fwnode_handle * fwnode,char * addr)600 int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr)
601 {
602 if (!fwnode_get_mac_addr(fwnode, "mac-address", addr) ||
603 !fwnode_get_mac_addr(fwnode, "local-mac-address", addr) ||
604 !fwnode_get_mac_addr(fwnode, "address", addr))
605 return 0;
606
607 return -ENOENT;
608 }
609 EXPORT_SYMBOL(fwnode_get_mac_address);
610
611 /**
612 * device_get_mac_address - Get the MAC for a given device
613 * @dev: Pointer to the device
614 * @addr: Address of buffer to store the MAC in
615 */
device_get_mac_address(struct device * dev,char * addr)616 int device_get_mac_address(struct device *dev, char *addr)
617 {
618 return fwnode_get_mac_address(dev_fwnode(dev), addr);
619 }
620 EXPORT_SYMBOL(device_get_mac_address);
621
622 /**
623 * device_get_ethdev_address - Set netdev's MAC address from a given device
624 * @dev: Pointer to the device
625 * @netdev: Pointer to netdev to write the address to
626 *
627 * Wrapper around device_get_mac_address() which writes the address
628 * directly to netdev->dev_addr.
629 */
device_get_ethdev_address(struct device * dev,struct net_device * netdev)630 int device_get_ethdev_address(struct device *dev, struct net_device *netdev)
631 {
632 u8 addr[ETH_ALEN];
633 int ret;
634
635 ret = device_get_mac_address(dev, addr);
636 if (!ret)
637 eth_hw_addr_set(netdev, addr);
638 return ret;
639 }
640 EXPORT_SYMBOL(device_get_ethdev_address);
641