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Linux/net/ethernet/eth.c

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  1 /*
  2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  3  *              operating system.  INET is implemented using the  BSD Socket
  4  *              interface as the means of communication with the user level.
  5  *
  6  *              Ethernet-type device handling.
  7  *
  8  * Version:     @(#)eth.c       1.0.7   05/25/93
  9  *
 10  * Authors:     Ross Biro
 11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 12  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
 13  *              Florian  La Roche, <rzsfl@rz.uni-sb.de>
 14  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
 15  *
 16  * Fixes:
 17  *              Mr Linux        : Arp problems
 18  *              Alan Cox        : Generic queue tidyup (very tiny here)
 19  *              Alan Cox        : eth_header ntohs should be htons
 20  *              Alan Cox        : eth_rebuild_header missing an htons and
 21  *                                minor other things.
 22  *              Tegge           : Arp bug fixes.
 23  *              Florian         : Removed many unnecessary functions, code cleanup
 24  *                                and changes for new arp and skbuff.
 25  *              Alan Cox        : Redid header building to reflect new format.
 26  *              Alan Cox        : ARP only when compiled with CONFIG_INET
 27  *              Greg Page       : 802.2 and SNAP stuff.
 28  *              Alan Cox        : MAC layer pointers/new format.
 29  *              Paul Gortmaker  : eth_copy_and_sum shouldn't csum padding.
 30  *              Alan Cox        : Protect against forwarding explosions with
 31  *                                older network drivers and IFF_ALLMULTI.
 32  *      Christer Weinigel       : Better rebuild header message.
 33  *             Andrew Morton    : 26Feb01: kill ether_setup() - use netdev_boot_setup().
 34  *
 35  *              This program is free software; you can redistribute it and/or
 36  *              modify it under the terms of the GNU General Public License
 37  *              as published by the Free Software Foundation; either version
 38  *              2 of the License, or (at your option) any later version.
 39  */
 40 #include <linux/module.h>
 41 #include <linux/types.h>
 42 #include <linux/kernel.h>
 43 #include <linux/string.h>
 44 #include <linux/mm.h>
 45 #include <linux/socket.h>
 46 #include <linux/in.h>
 47 #include <linux/inet.h>
 48 #include <linux/ip.h>
 49 #include <linux/netdevice.h>
 50 #include <linux/etherdevice.h>
 51 #include <linux/skbuff.h>
 52 #include <linux/errno.h>
 53 #include <linux/init.h>
 54 #include <linux/if_ether.h>
 55 #include <linux/of_net.h>
 56 #include <linux/pci.h>
 57 #include <net/dst.h>
 58 #include <net/arp.h>
 59 #include <net/sock.h>
 60 #include <net/ipv6.h>
 61 #include <net/ip.h>
 62 #include <net/dsa.h>
 63 #include <net/flow_dissector.h>
 64 #include <linux/uaccess.h>
 65 #include <net/pkt_sched.h>
 66 
 67 __setup("ether=", netdev_boot_setup);
 68 
 69 /**
 70  * eth_header - create the Ethernet header
 71  * @skb:        buffer to alter
 72  * @dev:        source device
 73  * @type:       Ethernet type field
 74  * @daddr: destination address (NULL leave destination address)
 75  * @saddr: source address (NULL use device source address)
 76  * @len:   packet length (<= skb->len)
 77  *
 78  *
 79  * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
 80  * in here instead.
 81  */
 82 int eth_header(struct sk_buff *skb, struct net_device *dev,
 83                unsigned short type,
 84                const void *daddr, const void *saddr, unsigned int len)
 85 {
 86         struct ethhdr *eth = skb_push(skb, ETH_HLEN);
 87 
 88         if (type != ETH_P_802_3 && type != ETH_P_802_2)
 89                 eth->h_proto = htons(type);
 90         else
 91                 eth->h_proto = htons(len);
 92 
 93         /*
 94          *      Set the source hardware address.
 95          */
 96 
 97         if (!saddr)
 98                 saddr = dev->dev_addr;
 99         memcpy(eth->h_source, saddr, ETH_ALEN);
100 
101         if (daddr) {
102                 memcpy(eth->h_dest, daddr, ETH_ALEN);
103                 return ETH_HLEN;
104         }
105 
106         /*
107          *      Anyway, the loopback-device should never use this function...
108          */
109 
110         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
111                 eth_zero_addr(eth->h_dest);
112                 return ETH_HLEN;
113         }
114 
115         return -ETH_HLEN;
116 }
117 EXPORT_SYMBOL(eth_header);
118 
119 /**
120  * eth_get_headlen - determine the length of header for an ethernet frame
121  * @data: pointer to start of frame
122  * @len: total length of frame
123  *
124  * Make a best effort attempt to pull the length for all of the headers for
125  * a given frame in a linear buffer.
126  */
127 u32 eth_get_headlen(void *data, unsigned int len)
128 {
129         const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
130         const struct ethhdr *eth = (const struct ethhdr *)data;
131         struct flow_keys keys;
132 
133         /* this should never happen, but better safe than sorry */
134         if (unlikely(len < sizeof(*eth)))
135                 return len;
136 
137         /* parse any remaining L2/L3 headers, check for L4 */
138         if (!skb_flow_dissect_flow_keys_buf(&keys, data, eth->h_proto,
139                                             sizeof(*eth), len, flags))
140                 return max_t(u32, keys.control.thoff, sizeof(*eth));
141 
142         /* parse for any L4 headers */
143         return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
144 }
145 EXPORT_SYMBOL(eth_get_headlen);
146 
147 /**
148  * eth_type_trans - determine the packet's protocol ID.
149  * @skb: received socket data
150  * @dev: receiving network device
151  *
152  * The rule here is that we
153  * assume 802.3 if the type field is short enough to be a length.
154  * This is normal practice and works for any 'now in use' protocol.
155  */
156 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
157 {
158         unsigned short _service_access_point;
159         const unsigned short *sap;
160         const struct ethhdr *eth;
161 
162         skb->dev = dev;
163         skb_reset_mac_header(skb);
164 
165         eth = (struct ethhdr *)skb->data;
166         skb_pull_inline(skb, ETH_HLEN);
167 
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;
171                 else
172                         skb->pkt_type = PACKET_MULTICAST;
173         }
174         else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
175                                                    dev->dev_addr)))
176                 skb->pkt_type = PACKET_OTHERHOST;
177 
178         /*
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.
183          */
184         if (unlikely(netdev_uses_dsa(dev)))
185                 return htons(ETH_P_XDSA);
186 
187         if (likely(eth_proto_is_802_3(eth->h_proto)))
188                 return eth->h_proto;
189 
190         /*
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.
195          */
196         sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
197         if (sap && *sap == 0xFFFF)
198                 return htons(ETH_P_802_3);
199 
200         /*
201          *      Real 802.2 LLC
202          */
203         return htons(ETH_P_802_2);
204 }
205 EXPORT_SYMBOL(eth_type_trans);
206 
207 /**
208  * eth_header_parse - extract hardware address from packet
209  * @skb: packet to extract header from
210  * @haddr: destination buffer
211  */
212 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
213 {
214         const struct ethhdr *eth = eth_hdr(skb);
215         memcpy(haddr, eth->h_source, ETH_ALEN);
216         return ETH_ALEN;
217 }
218 EXPORT_SYMBOL(eth_header_parse);
219 
220 /**
221  * eth_header_cache - fill cache entry from neighbour
222  * @neigh: source neighbour
223  * @hh: destination cache entry
224  * @type: Ethernet type field
225  *
226  * Create an Ethernet header template from the neighbour.
227  */
228 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
229 {
230         struct ethhdr *eth;
231         const struct net_device *dev = neigh->dev;
232 
233         eth = (struct ethhdr *)
234             (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
235 
236         if (type == htons(ETH_P_802_3))
237                 return -1;
238 
239         eth->h_proto = type;
240         memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
241         memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
242         hh->hh_len = ETH_HLEN;
243         return 0;
244 }
245 EXPORT_SYMBOL(eth_header_cache);
246 
247 /**
248  * eth_header_cache_update - update cache entry
249  * @hh: destination cache entry
250  * @dev: network device
251  * @haddr: new hardware address
252  *
253  * Called by Address Resolution module to notify changes in address.
254  */
255 void eth_header_cache_update(struct hh_cache *hh,
256                              const struct net_device *dev,
257                              const unsigned char *haddr)
258 {
259         memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
260                haddr, ETH_ALEN);
261 }
262 EXPORT_SYMBOL(eth_header_cache_update);
263 
264 /**
265  * eth_prepare_mac_addr_change - prepare for mac change
266  * @dev: network device
267  * @p: socket address
268  */
269 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
270 {
271         struct sockaddr *addr = p;
272 
273         if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
274                 return -EBUSY;
275         if (!is_valid_ether_addr(addr->sa_data))
276                 return -EADDRNOTAVAIL;
277         return 0;
278 }
279 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
280 
281 /**
282  * eth_commit_mac_addr_change - commit mac change
283  * @dev: network device
284  * @p: socket address
285  */
286 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
287 {
288         struct sockaddr *addr = p;
289 
290         memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
291 }
292 EXPORT_SYMBOL(eth_commit_mac_addr_change);
293 
294 /**
295  * eth_mac_addr - set new Ethernet hardware address
296  * @dev: network device
297  * @p: socket address
298  *
299  * Change hardware address of device.
300  *
301  * This doesn't change hardware matching, so needs to be overridden
302  * for most real devices.
303  */
304 int eth_mac_addr(struct net_device *dev, void *p)
305 {
306         int ret;
307 
308         ret = eth_prepare_mac_addr_change(dev, p);
309         if (ret < 0)
310                 return ret;
311         eth_commit_mac_addr_change(dev, p);
312         return 0;
313 }
314 EXPORT_SYMBOL(eth_mac_addr);
315 
316 /**
317  * eth_change_mtu - set new MTU size
318  * @dev: network device
319  * @new_mtu: new Maximum Transfer Unit
320  *
321  * Allow changing MTU size. Needs to be overridden for devices
322  * supporting jumbo frames.
323  */
324 int eth_change_mtu(struct net_device *dev, int new_mtu)
325 {
326         netdev_warn(dev, "%s is deprecated\n", __func__);
327         dev->mtu = new_mtu;
328         return 0;
329 }
330 EXPORT_SYMBOL(eth_change_mtu);
331 
332 int eth_validate_addr(struct net_device *dev)
333 {
334         if (!is_valid_ether_addr(dev->dev_addr))
335                 return -EADDRNOTAVAIL;
336 
337         return 0;
338 }
339 EXPORT_SYMBOL(eth_validate_addr);
340 
341 const struct header_ops eth_header_ops ____cacheline_aligned = {
342         .create         = eth_header,
343         .parse          = eth_header_parse,
344         .cache          = eth_header_cache,
345         .cache_update   = eth_header_cache_update,
346 };
347 
348 /**
349  * ether_setup - setup Ethernet network device
350  * @dev: network device
351  *
352  * Fill in the fields of the device structure with Ethernet-generic values.
353  */
354 void ether_setup(struct net_device *dev)
355 {
356         dev->header_ops         = &eth_header_ops;
357         dev->type               = ARPHRD_ETHER;
358         dev->hard_header_len    = ETH_HLEN;
359         dev->min_header_len     = ETH_HLEN;
360         dev->mtu                = ETH_DATA_LEN;
361         dev->min_mtu            = ETH_MIN_MTU;
362         dev->max_mtu            = ETH_DATA_LEN;
363         dev->addr_len           = ETH_ALEN;
364         dev->tx_queue_len       = DEFAULT_TX_QUEUE_LEN;
365         dev->flags              = IFF_BROADCAST|IFF_MULTICAST;
366         dev->priv_flags         |= IFF_TX_SKB_SHARING;
367 
368         eth_broadcast_addr(dev->broadcast);
369 
370 }
371 EXPORT_SYMBOL(ether_setup);
372 
373 /**
374  * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
375  * @sizeof_priv: Size of additional driver-private structure to be allocated
376  *      for this Ethernet device
377  * @txqs: The number of TX queues this device has.
378  * @rxqs: The number of RX queues this device has.
379  *
380  * Fill in the fields of the device structure with Ethernet-generic
381  * values. Basically does everything except registering the device.
382  *
383  * Constructs a new net device, complete with a private data area of
384  * size (sizeof_priv).  A 32-byte (not bit) alignment is enforced for
385  * this private data area.
386  */
387 
388 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
389                                       unsigned int rxqs)
390 {
391         return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
392                                 ether_setup, txqs, rxqs);
393 }
394 EXPORT_SYMBOL(alloc_etherdev_mqs);
395 
396 static void devm_free_netdev(struct device *dev, void *res)
397 {
398         free_netdev(*(struct net_device **)res);
399 }
400 
401 struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv,
402                                            unsigned int txqs, unsigned int rxqs)
403 {
404         struct net_device **dr;
405         struct net_device *netdev;
406 
407         dr = devres_alloc(devm_free_netdev, sizeof(*dr), GFP_KERNEL);
408         if (!dr)
409                 return NULL;
410 
411         netdev = alloc_etherdev_mqs(sizeof_priv, txqs, rxqs);
412         if (!netdev) {
413                 devres_free(dr);
414                 return NULL;
415         }
416 
417         *dr = netdev;
418         devres_add(dev, dr);
419 
420         return netdev;
421 }
422 EXPORT_SYMBOL(devm_alloc_etherdev_mqs);
423 
424 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
425 {
426         return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
427 }
428 EXPORT_SYMBOL(sysfs_format_mac);
429 
430 struct sk_buff **eth_gro_receive(struct sk_buff **head,
431                                  struct sk_buff *skb)
432 {
433         struct sk_buff *p, **pp = NULL;
434         struct ethhdr *eh, *eh2;
435         unsigned int hlen, off_eth;
436         const struct packet_offload *ptype;
437         __be16 type;
438         int flush = 1;
439 
440         off_eth = skb_gro_offset(skb);
441         hlen = off_eth + sizeof(*eh);
442         eh = skb_gro_header_fast(skb, off_eth);
443         if (skb_gro_header_hard(skb, hlen)) {
444                 eh = skb_gro_header_slow(skb, hlen, off_eth);
445                 if (unlikely(!eh))
446                         goto out;
447         }
448 
449         flush = 0;
450 
451         for (p = *head; p; p = p->next) {
452                 if (!NAPI_GRO_CB(p)->same_flow)
453                         continue;
454 
455                 eh2 = (struct ethhdr *)(p->data + off_eth);
456                 if (compare_ether_header(eh, eh2)) {
457                         NAPI_GRO_CB(p)->same_flow = 0;
458                         continue;
459                 }
460         }
461 
462         type = eh->h_proto;
463 
464         rcu_read_lock();
465         ptype = gro_find_receive_by_type(type);
466         if (ptype == NULL) {
467                 flush = 1;
468                 goto out_unlock;
469         }
470 
471         skb_gro_pull(skb, sizeof(*eh));
472         skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
473         pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
474 
475 out_unlock:
476         rcu_read_unlock();
477 out:
478         skb_gro_flush_final(skb, pp, flush);
479 
480         return pp;
481 }
482 EXPORT_SYMBOL(eth_gro_receive);
483 
484 int eth_gro_complete(struct sk_buff *skb, int nhoff)
485 {
486         struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
487         __be16 type = eh->h_proto;
488         struct packet_offload *ptype;
489         int err = -ENOSYS;
490 
491         if (skb->encapsulation)
492                 skb_set_inner_mac_header(skb, nhoff);
493 
494         rcu_read_lock();
495         ptype = gro_find_complete_by_type(type);
496         if (ptype != NULL)
497                 err = ptype->callbacks.gro_complete(skb, nhoff +
498                                                     sizeof(struct ethhdr));
499 
500         rcu_read_unlock();
501         return err;
502 }
503 EXPORT_SYMBOL(eth_gro_complete);
504 
505 static struct packet_offload eth_packet_offload __read_mostly = {
506         .type = cpu_to_be16(ETH_P_TEB),
507         .priority = 10,
508         .callbacks = {
509                 .gro_receive = eth_gro_receive,
510                 .gro_complete = eth_gro_complete,
511         },
512 };
513 
514 static int __init eth_offload_init(void)
515 {
516         dev_add_offload(&eth_packet_offload);
517 
518         return 0;
519 }
520 
521 fs_initcall(eth_offload_init);
522 
523 unsigned char * __weak arch_get_platform_mac_address(void)
524 {
525         return NULL;
526 }
527 
528 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
529 {
530         const unsigned char *addr;
531         struct device_node *dp;
532 
533         if (dev_is_pci(dev))
534                 dp = pci_device_to_OF_node(to_pci_dev(dev));
535         else
536                 dp = dev->of_node;
537 
538         addr = NULL;
539         if (dp)
540                 addr = of_get_mac_address(dp);
541         if (!addr)
542                 addr = arch_get_platform_mac_address();
543 
544         if (!addr)
545                 return -ENODEV;
546 
547         ether_addr_copy(mac_addr, addr);
548         return 0;
549 }
550 EXPORT_SYMBOL(eth_platform_get_mac_address);
551 

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