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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 struct ethhdr *eth = (const struct ethhdr *)data;
129         struct flow_keys 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_buf(&keys, data, eth->h_proto,
137                                             sizeof(*eth), len, 0))
138                 return max_t(u32, keys.control.thoff, sizeof(*eth));
139 
140         /* parse for any L4 headers */
141         return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
142 }
143 EXPORT_SYMBOL(eth_get_headlen);
144 
145 /**
146  * eth_type_trans - determine the packet's protocol ID.
147  * @skb: received socket data
148  * @dev: receiving network device
149  *
150  * The rule here is that we
151  * assume 802.3 if the type field is short enough to be a length.
152  * This is normal practice and works for any 'now in use' protocol.
153  */
154 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
155 {
156         unsigned short _service_access_point;
157         const unsigned short *sap;
158         const struct ethhdr *eth;
159 
160         skb->dev = dev;
161         skb_reset_mac_header(skb);
162 
163         eth = (struct ethhdr *)skb->data;
164         skb_pull_inline(skb, ETH_HLEN);
165 
166         if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) {
167                 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
168                         skb->pkt_type = PACKET_BROADCAST;
169                 else
170                         skb->pkt_type = PACKET_MULTICAST;
171         }
172         else if (unlikely(!ether_addr_equal_64bits(eth->h_dest,
173                                                    dev->dev_addr)))
174                 skb->pkt_type = PACKET_OTHERHOST;
175 
176         /*
177          * Some variants of DSA tagging don't have an ethertype field
178          * at all, so we check here whether one of those tagging
179          * variants has been configured on the receiving interface,
180          * and if so, set skb->protocol without looking at the packet.
181          */
182         if (unlikely(netdev_uses_dsa(dev)))
183                 return htons(ETH_P_XDSA);
184 
185         if (likely(eth_proto_is_802_3(eth->h_proto)))
186                 return eth->h_proto;
187 
188         /*
189          *      This is a magic hack to spot IPX packets. Older Novell breaks
190          *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
191          *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
192          *      won't work for fault tolerant netware but does for the rest.
193          */
194         sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point);
195         if (sap && *sap == 0xFFFF)
196                 return htons(ETH_P_802_3);
197 
198         /*
199          *      Real 802.2 LLC
200          */
201         return htons(ETH_P_802_2);
202 }
203 EXPORT_SYMBOL(eth_type_trans);
204 
205 /**
206  * eth_header_parse - extract hardware address from packet
207  * @skb: packet to extract header from
208  * @haddr: destination buffer
209  */
210 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
211 {
212         const struct ethhdr *eth = eth_hdr(skb);
213         memcpy(haddr, eth->h_source, ETH_ALEN);
214         return ETH_ALEN;
215 }
216 EXPORT_SYMBOL(eth_header_parse);
217 
218 /**
219  * eth_header_cache - fill cache entry from neighbour
220  * @neigh: source neighbour
221  * @hh: destination cache entry
222  * @type: Ethernet type field
223  *
224  * Create an Ethernet header template from the neighbour.
225  */
226 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
227 {
228         struct ethhdr *eth;
229         const struct net_device *dev = neigh->dev;
230 
231         eth = (struct ethhdr *)
232             (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
233 
234         if (type == htons(ETH_P_802_3))
235                 return -1;
236 
237         eth->h_proto = type;
238         memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
239         memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
240         hh->hh_len = ETH_HLEN;
241         return 0;
242 }
243 EXPORT_SYMBOL(eth_header_cache);
244 
245 /**
246  * eth_header_cache_update - update cache entry
247  * @hh: destination cache entry
248  * @dev: network device
249  * @haddr: new hardware address
250  *
251  * Called by Address Resolution module to notify changes in address.
252  */
253 void eth_header_cache_update(struct hh_cache *hh,
254                              const struct net_device *dev,
255                              const unsigned char *haddr)
256 {
257         memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
258                haddr, ETH_ALEN);
259 }
260 EXPORT_SYMBOL(eth_header_cache_update);
261 
262 /**
263  * eth_prepare_mac_addr_change - prepare for mac change
264  * @dev: network device
265  * @p: socket address
266  */
267 int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
268 {
269         struct sockaddr *addr = p;
270 
271         if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
272                 return -EBUSY;
273         if (!is_valid_ether_addr(addr->sa_data))
274                 return -EADDRNOTAVAIL;
275         return 0;
276 }
277 EXPORT_SYMBOL(eth_prepare_mac_addr_change);
278 
279 /**
280  * eth_commit_mac_addr_change - commit mac change
281  * @dev: network device
282  * @p: socket address
283  */
284 void eth_commit_mac_addr_change(struct net_device *dev, void *p)
285 {
286         struct sockaddr *addr = p;
287 
288         memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
289 }
290 EXPORT_SYMBOL(eth_commit_mac_addr_change);
291 
292 /**
293  * eth_mac_addr - set new Ethernet hardware address
294  * @dev: network device
295  * @p: socket address
296  *
297  * Change hardware address of device.
298  *
299  * This doesn't change hardware matching, so needs to be overridden
300  * for most real devices.
301  */
302 int eth_mac_addr(struct net_device *dev, void *p)
303 {
304         int ret;
305 
306         ret = eth_prepare_mac_addr_change(dev, p);
307         if (ret < 0)
308                 return ret;
309         eth_commit_mac_addr_change(dev, p);
310         return 0;
311 }
312 EXPORT_SYMBOL(eth_mac_addr);
313 
314 /**
315  * eth_change_mtu - set new MTU size
316  * @dev: network device
317  * @new_mtu: new Maximum Transfer Unit
318  *
319  * Allow changing MTU size. Needs to be overridden for devices
320  * supporting jumbo frames.
321  */
322 int eth_change_mtu(struct net_device *dev, int new_mtu)
323 {
324         if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
325                 return -EINVAL;
326         dev->mtu = new_mtu;
327         return 0;
328 }
329 EXPORT_SYMBOL(eth_change_mtu);
330 
331 int eth_validate_addr(struct net_device *dev)
332 {
333         if (!is_valid_ether_addr(dev->dev_addr))
334                 return -EADDRNOTAVAIL;
335 
336         return 0;
337 }
338 EXPORT_SYMBOL(eth_validate_addr);
339 
340 const struct header_ops eth_header_ops ____cacheline_aligned = {
341         .create         = eth_header,
342         .parse          = eth_header_parse,
343         .cache          = eth_header_cache,
344         .cache_update   = eth_header_cache_update,
345 };
346 
347 /**
348  * ether_setup - setup Ethernet network device
349  * @dev: network device
350  *
351  * Fill in the fields of the device structure with Ethernet-generic values.
352  */
353 void ether_setup(struct net_device *dev)
354 {
355         dev->header_ops         = &eth_header_ops;
356         dev->type               = ARPHRD_ETHER;
357         dev->hard_header_len    = ETH_HLEN;
358         dev->mtu                = ETH_DATA_LEN;
359         dev->addr_len           = ETH_ALEN;
360         dev->tx_queue_len       = 1000; /* Ethernet wants good queues */
361         dev->flags              = IFF_BROADCAST|IFF_MULTICAST;
362         dev->priv_flags         |= IFF_TX_SKB_SHARING;
363 
364         eth_broadcast_addr(dev->broadcast);
365 
366 }
367 EXPORT_SYMBOL(ether_setup);
368 
369 /**
370  * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
371  * @sizeof_priv: Size of additional driver-private structure to be allocated
372  *      for this Ethernet device
373  * @txqs: The number of TX queues this device has.
374  * @rxqs: The number of RX queues this device has.
375  *
376  * Fill in the fields of the device structure with Ethernet-generic
377  * values. Basically does everything except registering the device.
378  *
379  * Constructs a new net device, complete with a private data area of
380  * size (sizeof_priv).  A 32-byte (not bit) alignment is enforced for
381  * this private data area.
382  */
383 
384 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
385                                       unsigned int rxqs)
386 {
387         return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN,
388                                 ether_setup, txqs, rxqs);
389 }
390 EXPORT_SYMBOL(alloc_etherdev_mqs);
391 
392 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
393 {
394         return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr);
395 }
396 EXPORT_SYMBOL(sysfs_format_mac);
397 
398 struct sk_buff **eth_gro_receive(struct sk_buff **head,
399                                  struct sk_buff *skb)
400 {
401         struct sk_buff *p, **pp = NULL;
402         struct ethhdr *eh, *eh2;
403         unsigned int hlen, off_eth;
404         const struct packet_offload *ptype;
405         __be16 type;
406         int flush = 1;
407 
408         off_eth = skb_gro_offset(skb);
409         hlen = off_eth + sizeof(*eh);
410         eh = skb_gro_header_fast(skb, off_eth);
411         if (skb_gro_header_hard(skb, hlen)) {
412                 eh = skb_gro_header_slow(skb, hlen, off_eth);
413                 if (unlikely(!eh))
414                         goto out;
415         }
416 
417         flush = 0;
418 
419         for (p = *head; p; p = p->next) {
420                 if (!NAPI_GRO_CB(p)->same_flow)
421                         continue;
422 
423                 eh2 = (struct ethhdr *)(p->data + off_eth);
424                 if (compare_ether_header(eh, eh2)) {
425                         NAPI_GRO_CB(p)->same_flow = 0;
426                         continue;
427                 }
428         }
429 
430         type = eh->h_proto;
431 
432         rcu_read_lock();
433         ptype = gro_find_receive_by_type(type);
434         if (ptype == NULL) {
435                 flush = 1;
436                 goto out_unlock;
437         }
438 
439         skb_gro_pull(skb, sizeof(*eh));
440         skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
441         pp = ptype->callbacks.gro_receive(head, skb);
442 
443 out_unlock:
444         rcu_read_unlock();
445 out:
446         NAPI_GRO_CB(skb)->flush |= flush;
447 
448         return pp;
449 }
450 EXPORT_SYMBOL(eth_gro_receive);
451 
452 int eth_gro_complete(struct sk_buff *skb, int nhoff)
453 {
454         struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
455         __be16 type = eh->h_proto;
456         struct packet_offload *ptype;
457         int err = -ENOSYS;
458 
459         if (skb->encapsulation)
460                 skb_set_inner_mac_header(skb, nhoff);
461 
462         rcu_read_lock();
463         ptype = gro_find_complete_by_type(type);
464         if (ptype != NULL)
465                 err = ptype->callbacks.gro_complete(skb, nhoff +
466                                                     sizeof(struct ethhdr));
467 
468         rcu_read_unlock();
469         return err;
470 }
471 EXPORT_SYMBOL(eth_gro_complete);
472 
473 static struct packet_offload eth_packet_offload __read_mostly = {
474         .type = cpu_to_be16(ETH_P_TEB),
475         .priority = 10,
476         .callbacks = {
477                 .gro_receive = eth_gro_receive,
478                 .gro_complete = eth_gro_complete,
479         },
480 };
481 
482 static int __init eth_offload_init(void)
483 {
484         dev_add_offload(&eth_packet_offload);
485 
486         return 0;
487 }
488 
489 fs_initcall(eth_offload_init);
490 
491 unsigned char * __weak arch_get_platform_mac_address(void)
492 {
493         return NULL;
494 }
495 
496 int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
497 {
498         const unsigned char *addr;
499         struct device_node *dp;
500 
501         if (dev_is_pci(dev))
502                 dp = pci_device_to_OF_node(to_pci_dev(dev));
503         else
504                 dp = dev->of_node;
505 
506         addr = NULL;
507         if (dp)
508                 addr = of_get_mac_address(dp);
509         if (!addr)
510                 addr = arch_get_platform_mac_address();
511 
512         if (!addr)
513                 return -ENODEV;
514 
515         ether_addr_copy(mac_addr, addr);
516         return 0;
517 }
518 EXPORT_SYMBOL(eth_platform_get_mac_address);
519 

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