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Linux/net/ethernet/eth.c

  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 
 66 __setup("ether=", netdev_boot_setup);
 67 
 68 /**
 69  * eth_header - create the Ethernet header
 70  * @skb:        buffer to alter
 71  * @dev:        source device
 72  * @type:       Ethernet type field
 73  * @daddr: destination address (NULL leave destination address)
 74  * @saddr: source address (NULL use device source address)
 75  * @len:   packet length (<= skb->len)
 76  *
 77  *
 78  * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
 79  * in here instead.
 80  */
 81 int eth_header(struct sk_buff *skb, struct net_device *dev,
 82                unsigned short type,
 83                const void *daddr, const void *saddr, unsigned int len)
 84 {
 85         struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
 86 
 87         if (type != ETH_P_802_3 && type != ETH_P_802_2)
 88                 eth->h_proto = htons(type);
 89         else
 90                 eth->h_proto = htons(len);
 91 
 92         /*
 93          *      Set the source hardware address.
 94          */
 95 
 96         if (!saddr)
 97                 saddr = dev->dev_addr;
 98         memcpy(eth->h_source, saddr, ETH_ALEN);
 99 
100         if (daddr) {
101                 memcpy(eth->h_dest, daddr, ETH_ALEN);
102                 return ETH_HLEN;
103         }
104 
105         /*
106          *      Anyway, the loopback-device should never use this function...
107          */
108 
109         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
110                 eth_zero_addr(eth->h_dest);
111                 return ETH_HLEN;
112         }
113 
114         return -ETH_HLEN;
115 }
116 EXPORT_SYMBOL(eth_header);
117 
118 /**
119  * eth_get_headlen - determine the length of header for an ethernet frame
120  * @data: pointer to start of frame
121  * @len: total length of frame
122  *
123  * Make a best effort attempt to pull the length for all of the headers for
124  * a given frame in a linear buffer.
125  */
126 u32 eth_get_headlen(void *data, unsigned int len)
127 {
128         const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
129         const struct ethhdr *eth = (const struct ethhdr *)data;
130         struct flow_keys keys;
131 
132         /* this should never happen, but better safe than sorry */
133         if (unlikely(len < sizeof(*eth)))
134                 return len;
135 
136         /* parse any remaining L2/L3 headers, check for L4 */
137         if (!skb_flow_dissect_flow_keys_buf(&keys, data, eth->h_proto,
138                                             sizeof(*eth), 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  */
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         if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
168                 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
169                         skb->pkt_type = PACKET_BROADCAST;
170                 else
171                         skb->pkt_type = PACKET_MULTICAST;
172         }
173         else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
174                                                    dev->dev_addr)))
175                 skb->pkt_type = PACKET_OTHERHOST;
176 
177         /*
178          * Some variants of DSA tagging don't have an ethertype field
179          * at all, so we check here whether one of those tagging
180          * variants has been configured on the receiving interface,
181          * and if so, set skb->protocol without looking at the packet.
182          */
183         if (unlikely(netdev_uses_dsa(dev)))
184                 return htons(ETH_P_XDSA);
185 
186         if (likely(eth_proto_is_802_3(eth->h_proto)))
187                 return eth->h_proto;
188 
189         /*
190          *      This is a magic hack to spot IPX packets. Older Novell breaks
191          *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
192          *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
193          *      won't work for fault tolerant netware but does for the rest.
194          */
195         sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
196         if (sap && *sap == 0xFFFF)
197                 return htons(ETH_P_802_3);
198 
199         /*
200          *      Real 802.2 LLC
201          */
202         return htons(ETH_P_802_2);
203 }
204 EXPORT_SYMBOL(eth_type_trans);
205 
206 /**
207  * eth_header_parse - extract hardware address from packet
208  * @skb: packet to extract header from
209  * @haddr: destination buffer
210  */
211 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
212 {
213         const struct ethhdr *eth = eth_hdr(skb);
214         memcpy(haddr, eth->h_source, ETH_ALEN);
215         return ETH_ALEN;
216 }
217 EXPORT_SYMBOL(eth_header_parse);
218 
219 /**
220  * eth_header_cache - fill cache entry from neighbour
221  * @neigh: source neighbour
222  * @hh: destination cache entry
223  * @type: Ethernet type field
224  *
225  * Create an Ethernet header template from the neighbour.
226  */
227 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
228 {
229         struct ethhdr *eth;
230         const struct net_device *dev = neigh->dev;
231 
232         eth = (struct ethhdr *)
233             (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
234 
235         if (type == htons(ETH_P_802_3))
236                 return -1;
237 
238         eth->h_proto = type;
239         memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
240         memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
241         hh->hh_len = ETH_HLEN;
242         return 0;
243 }
244 EXPORT_SYMBOL(eth_header_cache);
245 
246 /**
247  * eth_header_cache_update - update cache entry
248  * @hh: destination cache entry
249  * @dev: network device
250  * @haddr: new hardware address
251  *
252  * Called by Address Resolution module to notify changes in address.
253  */
254 void eth_header_cache_update(struct hh_cache *hh,
255                              const struct net_device *dev,
256                              const unsigned char *haddr)
257 {
258         memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
259                haddr, ETH_ALEN);
260 }
261 EXPORT_SYMBOL(eth_header_cache_update);
262 
263 /**
264  * eth_prepare_mac_addr_change - prepare for mac change
265  * @dev: network device
266  * @p: socket address
267  */
268 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
269 {
270         struct sockaddr *addr = p;
271 
272         if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
273                 return -EBUSY;
274         if (!is_valid_ether_addr(addr->sa_data))
275                 return -EADDRNOTAVAIL;
276         return 0;
277 }
278 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
279 
280 /**
281  * eth_commit_mac_addr_change - commit mac change
282  * @dev: network device
283  * @p: socket address
284  */
285 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
286 {
287         struct sockaddr *addr = p;
288 
289         memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
290 }
291 EXPORT_SYMBOL(eth_commit_mac_addr_change);
292 
293 /**
294  * eth_mac_addr - set new Ethernet hardware address
295  * @dev: network device
296  * @p: socket address
297  *
298  * Change hardware address of device.
299  *
300  * This doesn't change hardware matching, so needs to be overridden
301  * for most real devices.
302  */
303 int eth_mac_addr(struct net_device *dev, void *p)
304 {
305         int ret;
306 
307         ret = eth_prepare_mac_addr_change(dev, p);
308         if (ret < 0)
309                 return ret;
310         eth_commit_mac_addr_change(dev, p);
311         return 0;
312 }
313 EXPORT_SYMBOL(eth_mac_addr);
314 
315 /**
316  * eth_change_mtu - set new MTU size
317  * @dev: network device
318  * @new_mtu: new Maximum Transfer Unit
319  *
320  * Allow changing MTU size. Needs to be overridden for devices
321  * supporting jumbo frames.
322  */
323 int eth_change_mtu(struct net_device *dev, int new_mtu)
324 {
325         if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
326                 return -EINVAL;
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->mtu                = ETH_DATA_LEN;
360         dev->addr_len           = ETH_ALEN;
361         dev->tx_queue_len       = 1000; /* Ethernet wants good queues */
362         dev->flags              = IFF_BROADCAST|IFF_MULTICAST;
363         dev->priv_flags         |= IFF_TX_SKB_SHARING;
364 
365         eth_broadcast_addr(dev->broadcast);
366 
367 }
368 EXPORT_SYMBOL(ether_setup);
369 
370 /**
371  * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
372  * @sizeof_priv: Size of additional driver-private structure to be allocated
373  *      for this Ethernet device
374  * @txqs: The number of TX queues this device has.
375  * @rxqs: The number of RX queues this device has.
376  *
377  * Fill in the fields of the device structure with Ethernet-generic
378  * values. Basically does everything except registering the device.
379  *
380  * Constructs a new net device, complete with a private data area of
381  * size (sizeof_priv).  A 32-byte (not bit) alignment is enforced for
382  * this private data area.
383  */
384 
385 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
386                                       unsigned int rxqs)
387 {
388         return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
389                                 ether_setup, txqs, rxqs);
390 }
391 EXPORT_SYMBOL(alloc_etherdev_mqs);
392 
393 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
394 {
395         return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
396 }
397 EXPORT_SYMBOL(sysfs_format_mac);
398 
399 struct sk_buff **eth_gro_receive(struct sk_buff **head,
400                                  struct sk_buff *skb)
401 {
402         struct sk_buff *p, **pp = NULL;
403         struct ethhdr *eh, *eh2;
404         unsigned int hlen, off_eth;
405         const struct packet_offload *ptype;
406         __be16 type;
407         int flush = 1;
408 
409         off_eth = skb_gro_offset(skb);
410         hlen = off_eth + sizeof(*eh);
411         eh = skb_gro_header_fast(skb, off_eth);
412         if (skb_gro_header_hard(skb, hlen)) {
413                 eh = skb_gro_header_slow(skb, hlen, off_eth);
414                 if (unlikely(!eh))
415                         goto out;
416         }
417 
418         flush = 0;
419 
420         for (p = *head; p; p = p->next) {
421                 if (!NAPI_GRO_CB(p)->same_flow)
422                         continue;
423 
424                 eh2 = (struct ethhdr *)(p->data + off_eth);
425                 if (compare_ether_header(eh, eh2)) {
426                         NAPI_GRO_CB(p)->same_flow = 0;
427                         continue;
428                 }
429         }
430 
431         type = eh->h_proto;
432 
433         rcu_read_lock();
434         ptype = gro_find_receive_by_type(type);
435         if (ptype == NULL) {
436                 flush = 1;
437                 goto out_unlock;
438         }
439 
440         skb_gro_pull(skb, sizeof(*eh));
441         skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
442         pp = ptype->callbacks.gro_receive(head, skb);
443 
444 out_unlock:
445         rcu_read_unlock();
446 out:
447         NAPI_GRO_CB(skb)->flush |= flush;
448 
449         return pp;
450 }
451 EXPORT_SYMBOL(eth_gro_receive);
452 
453 int eth_gro_complete(struct sk_buff *skb, int nhoff)
454 {
455         struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
456         __be16 type = eh->h_proto;
457         struct packet_offload *ptype;
458         int err = -ENOSYS;
459 
460         if (skb->encapsulation)
461                 skb_set_inner_mac_header(skb, nhoff);
462 
463         rcu_read_lock();
464         ptype = gro_find_complete_by_type(type);
465         if (ptype != NULL)
466                 err = ptype->callbacks.gro_complete(skb, nhoff +
467                                                     sizeof(struct ethhdr));
468 
469         rcu_read_unlock();
470         return err;
471 }
472 EXPORT_SYMBOL(eth_gro_complete);
473 
474 static struct packet_offload eth_packet_offload __read_mostly = {
475         .type = cpu_to_be16(ETH_P_TEB),
476         .priority = 10,
477         .callbacks = {
478                 .gro_receive = eth_gro_receive,
479                 .gro_complete = eth_gro_complete,
480         },
481 };
482 
483 static int __init eth_offload_init(void)
484 {
485         dev_add_offload(&eth_packet_offload);
486 
487         return 0;
488 }
489 
490 fs_initcall(eth_offload_init);
491 
492 unsigned char * __weak arch_get_platform_mac_address(void)
493 {
494         return NULL;
495 }
496 
497 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
498 {
499         const unsigned char *addr;
500         struct device_node *dp;
501 
502         if (dev_is_pci(dev))
503                 dp = pci_device_to_OF_node(to_pci_dev(dev));
504         else
505                 dp = dev->of_node;
506 
507         addr = NULL;
508         if (dp)
509                 addr = of_get_mac_address(dp);
510         if (!addr)
511                 addr = arch_get_platform_mac_address();
512 
513         if (!addr)
514                 return -ENODEV;
515 
516         ether_addr_copy(mac_addr, addr);
517         return 0;
518 }
519 EXPORT_SYMBOL(eth_platform_get_mac_address);
520 

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