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 <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 <linux/uaccess.h> 63 64 __setup("ether=", netdev_boot_setup); 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 */ 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 = (struct ethhdr *)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 * @data: pointer to start of frame 119 * @len: total length of frame 120 * 121 * Make a best effort attempt to pull the length for all of the headers for 122 * a given frame in a linear buffer. 123 */ 124 u32 eth_get_headlen(void *data, unsigned int len) 125 { 126 const struct ethhdr *eth = (const struct ethhdr *)data; 127 struct flow_keys keys; 128 129 /* this should never happen, but better safe than sorry */ 130 if (unlikely(len < sizeof(*eth))) 131 return len; 132 133 /* parse any remaining L2/L3 headers, check for L4 */ 134 if (!skb_flow_dissect_flow_keys_buf(&keys, data, eth->h_proto, 135 sizeof(*eth), len, 0)) 136 return max_t(u32, keys.control.thoff, sizeof(*eth)); 137 138 /* parse for any L4 headers */ 139 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len); 140 } 141 EXPORT_SYMBOL(eth_get_headlen); 142 143 /** 144 * eth_type_trans - determine the packet's protocol ID. 145 * @skb: received socket data 146 * @dev: receiving network device 147 * 148 * The rule here is that we 149 * assume 802.3 if the type field is short enough to be a length. 150 * This is normal practice and works for any 'now in use' protocol. 151 */ 152 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) 153 { 154 unsigned short _service_access_point; 155 const unsigned short *sap; 156 const struct ethhdr *eth; 157 158 skb->dev = dev; 159 skb_reset_mac_header(skb); 160 161 eth = (struct ethhdr *)skb->data; 162 skb_pull_inline(skb, ETH_HLEN); 163 164 if (unlikely(is_multicast_ether_addr_64bits(eth->h_dest))) { 165 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast)) 166 skb->pkt_type = PACKET_BROADCAST; 167 else 168 skb->pkt_type = PACKET_MULTICAST; 169 } 170 else if (unlikely(!ether_addr_equal_64bits(eth->h_dest, 171 dev->dev_addr))) 172 skb->pkt_type = PACKET_OTHERHOST; 173 174 /* 175 * Some variants of DSA tagging don't have an ethertype field 176 * at all, so we check here whether one of those tagging 177 * variants has been configured on the receiving interface, 178 * and if so, set skb->protocol without looking at the packet. 179 */ 180 if (unlikely(netdev_uses_dsa(dev))) 181 return htons(ETH_P_XDSA); 182 183 if (likely(eth_proto_is_802_3(eth->h_proto))) 184 return eth->h_proto; 185 186 /* 187 * This is a magic hack to spot IPX packets. Older Novell breaks 188 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 189 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 190 * won't work for fault tolerant netware but does for the rest. 191 */ 192 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point); 193 if (sap && *sap == 0xFFFF) 194 return htons(ETH_P_802_3); 195 196 /* 197 * Real 802.2 LLC 198 */ 199 return htons(ETH_P_802_2); 200 } 201 EXPORT_SYMBOL(eth_type_trans); 202 203 /** 204 * eth_header_parse - extract hardware address from packet 205 * @skb: packet to extract header from 206 * @haddr: destination buffer 207 */ 208 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr) 209 { 210 const struct ethhdr *eth = eth_hdr(skb); 211 memcpy(haddr, eth->h_source, ETH_ALEN); 212 return ETH_ALEN; 213 } 214 EXPORT_SYMBOL(eth_header_parse); 215 216 /** 217 * eth_header_cache - fill cache entry from neighbour 218 * @neigh: source neighbour 219 * @hh: destination cache entry 220 * @type: Ethernet type field 221 * 222 * Create an Ethernet header template from the neighbour. 223 */ 224 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type) 225 { 226 struct ethhdr *eth; 227 const struct net_device *dev = neigh->dev; 228 229 eth = (struct ethhdr *) 230 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 231 232 if (type == htons(ETH_P_802_3)) 233 return -1; 234 235 eth->h_proto = type; 236 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 237 memcpy(eth->h_dest, neigh->ha, ETH_ALEN); 238 hh->hh_len = ETH_HLEN; 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 */ 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_prepare_mac_addr_change - prepare for mac change 262 * @dev: network device 263 * @p: socket address 264 */ 265 int eth_prepare_mac_addr_change(struct net_device *dev, void *p) 266 { 267 struct sockaddr *addr = p; 268 269 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev)) 270 return -EBUSY; 271 if (!is_valid_ether_addr(addr->sa_data)) 272 return -EADDRNOTAVAIL; 273 return 0; 274 } 275 EXPORT_SYMBOL(eth_prepare_mac_addr_change); 276 277 /** 278 * eth_commit_mac_addr_change - commit mac change 279 * @dev: network device 280 * @p: socket address 281 */ 282 void eth_commit_mac_addr_change(struct net_device *dev, void *p) 283 { 284 struct sockaddr *addr = p; 285 286 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); 287 } 288 EXPORT_SYMBOL(eth_commit_mac_addr_change); 289 290 /** 291 * eth_mac_addr - set new Ethernet hardware address 292 * @dev: network device 293 * @p: socket address 294 * 295 * Change hardware address of device. 296 * 297 * This doesn't change hardware matching, so needs to be overridden 298 * for most real devices. 299 */ 300 int eth_mac_addr(struct net_device *dev, void *p) 301 { 302 int ret; 303 304 ret = eth_prepare_mac_addr_change(dev, p); 305 if (ret < 0) 306 return ret; 307 eth_commit_mac_addr_change(dev, p); 308 return 0; 309 } 310 EXPORT_SYMBOL(eth_mac_addr); 311 312 /** 313 * eth_change_mtu - set new MTU size 314 * @dev: network device 315 * @new_mtu: new Maximum Transfer Unit 316 * 317 * Allow changing MTU size. Needs to be overridden for devices 318 * supporting jumbo frames. 319 */ 320 int eth_change_mtu(struct net_device *dev, int new_mtu) 321 { 322 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 323 return -EINVAL; 324 dev->mtu = new_mtu; 325 return 0; 326 } 327 EXPORT_SYMBOL(eth_change_mtu); 328 329 int eth_validate_addr(struct net_device *dev) 330 { 331 if (!is_valid_ether_addr(dev->dev_addr)) 332 return -EADDRNOTAVAIL; 333 334 return 0; 335 } 336 EXPORT_SYMBOL(eth_validate_addr); 337 338 const struct header_ops eth_header_ops ____cacheline_aligned = { 339 .create = eth_header, 340 .parse = eth_header_parse, 341 .cache = eth_header_cache, 342 .cache_update = eth_header_cache_update, 343 }; 344 345 /** 346 * ether_setup - setup Ethernet network device 347 * @dev: network device 348 * 349 * Fill in the fields of the device structure with Ethernet-generic values. 350 */ 351 void ether_setup(struct net_device *dev) 352 { 353 dev->header_ops = ð_header_ops; 354 dev->type = ARPHRD_ETHER; 355 dev->hard_header_len = ETH_HLEN; 356 dev->mtu = ETH_DATA_LEN; 357 dev->addr_len = ETH_ALEN; 358 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 359 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 360 dev->priv_flags |= IFF_TX_SKB_SHARING; 361 362 eth_broadcast_addr(dev->broadcast); 363 364 } 365 EXPORT_SYMBOL(ether_setup); 366 367 /** 368 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device 369 * @sizeof_priv: Size of additional driver-private structure to be allocated 370 * for this Ethernet device 371 * @txqs: The number of TX queues this device has. 372 * @rxqs: The number of RX queues this device has. 373 * 374 * Fill in the fields of the device structure with Ethernet-generic 375 * values. Basically does everything except registering the device. 376 * 377 * Constructs a new net device, complete with a private data area of 378 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for 379 * this private data area. 380 */ 381 382 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs, 383 unsigned int rxqs) 384 { 385 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN, 386 ether_setup, txqs, rxqs); 387 } 388 EXPORT_SYMBOL(alloc_etherdev_mqs); 389 390 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len) 391 { 392 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr); 393 } 394 EXPORT_SYMBOL(sysfs_format_mac); 395 396 struct sk_buff **eth_gro_receive(struct sk_buff **head, 397 struct sk_buff *skb) 398 { 399 struct sk_buff *p, **pp = NULL; 400 struct ethhdr *eh, *eh2; 401 unsigned int hlen, off_eth; 402 const struct packet_offload *ptype; 403 __be16 type; 404 int flush = 1; 405 406 off_eth = skb_gro_offset(skb); 407 hlen = off_eth + sizeof(*eh); 408 eh = skb_gro_header_fast(skb, off_eth); 409 if (skb_gro_header_hard(skb, hlen)) { 410 eh = skb_gro_header_slow(skb, hlen, off_eth); 411 if (unlikely(!eh)) 412 goto out; 413 } 414 415 flush = 0; 416 417 for (p = *head; p; p = p->next) { 418 if (!NAPI_GRO_CB(p)->same_flow) 419 continue; 420 421 eh2 = (struct ethhdr *)(p->data + off_eth); 422 if (compare_ether_header(eh, eh2)) { 423 NAPI_GRO_CB(p)->same_flow = 0; 424 continue; 425 } 426 } 427 428 type = eh->h_proto; 429 430 rcu_read_lock(); 431 ptype = gro_find_receive_by_type(type); 432 if (ptype == NULL) { 433 flush = 1; 434 goto out_unlock; 435 } 436 437 skb_gro_pull(skb, sizeof(*eh)); 438 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh)); 439 pp = ptype->callbacks.gro_receive(head, skb); 440 441 out_unlock: 442 rcu_read_unlock(); 443 out: 444 NAPI_GRO_CB(skb)->flush |= flush; 445 446 return pp; 447 } 448 EXPORT_SYMBOL(eth_gro_receive); 449 450 int eth_gro_complete(struct sk_buff *skb, int nhoff) 451 { 452 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff); 453 __be16 type = eh->h_proto; 454 struct packet_offload *ptype; 455 int err = -ENOSYS; 456 457 if (skb->encapsulation) 458 skb_set_inner_mac_header(skb, nhoff); 459 460 rcu_read_lock(); 461 ptype = gro_find_complete_by_type(type); 462 if (ptype != NULL) 463 err = ptype->callbacks.gro_complete(skb, nhoff + 464 sizeof(struct ethhdr)); 465 466 rcu_read_unlock(); 467 return err; 468 } 469 EXPORT_SYMBOL(eth_gro_complete); 470 471 static struct packet_offload eth_packet_offload __read_mostly = { 472 .type = cpu_to_be16(ETH_P_TEB), 473 .priority = 10, 474 .callbacks = { 475 .gro_receive = eth_gro_receive, 476 .gro_complete = eth_gro_complete, 477 }, 478 }; 479 480 static int __init eth_offload_init(void) 481 { 482 dev_add_offload(ð_packet_offload); 483 484 return 0; 485 } 486 487 fs_initcall(eth_offload_init); 488