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 <linux/uaccess.h> 62 63 __setup("ether=", netdev_boot_setup); 64 65 /** 66 * eth_header - create the Ethernet header 67 * @skb: buffer to alter 68 * @dev: source device 69 * @type: Ethernet type field 70 * @daddr: destination address (NULL leave destination address) 71 * @saddr: source address (NULL use device source address) 72 * @len: packet length (<= skb->len) 73 * 74 * 75 * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length 76 * in here instead. 77 */ 78 int eth_header(struct sk_buff *skb, struct net_device *dev, 79 unsigned short type, 80 const void *daddr, const void *saddr, unsigned int len) 81 { 82 struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN); 83 84 if (type != ETH_P_802_3 && type != ETH_P_802_2) 85 eth->h_proto = htons(type); 86 else 87 eth->h_proto = htons(len); 88 89 /* 90 * Set the source hardware address. 91 */ 92 93 if (!saddr) 94 saddr = dev->dev_addr; 95 memcpy(eth->h_source, saddr, ETH_ALEN); 96 97 if (daddr) { 98 memcpy(eth->h_dest, daddr, ETH_ALEN); 99 return ETH_HLEN; 100 } 101 102 /* 103 * Anyway, the loopback-device should never use this function... 104 */ 105 106 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 107 eth_zero_addr(eth->h_dest); 108 return ETH_HLEN; 109 } 110 111 return -ETH_HLEN; 112 } 113 EXPORT_SYMBOL(eth_header); 114 115 /** 116 * eth_get_headlen - determine the the length of header for an ethernet frame 117 * @data: pointer to start of frame 118 * @len: total length of frame 119 * 120 * Make a best effort attempt to pull the length for all of the headers for 121 * a given frame in a linear buffer. 122 */ 123 u32 eth_get_headlen(void *data, unsigned int len) 124 { 125 const struct ethhdr *eth = (const struct ethhdr *)data; 126 struct flow_keys keys; 127 128 /* this should never happen, but better safe than sorry */ 129 if (len < sizeof(*eth)) 130 return len; 131 132 /* parse any remaining L2/L3 headers, check for L4 */ 133 if (!__skb_flow_dissect(NULL, &keys, data, 134 eth->h_proto, sizeof(*eth), len)) 135 return max_t(u32, keys.thoff, sizeof(*eth)); 136 137 /* parse for any L4 headers */ 138 return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len); 139 } 140 EXPORT_SYMBOL(eth_get_headlen); 141 142 /** 143 * eth_type_trans - determine the packet's protocol ID. 144 * @skb: received socket data 145 * @dev: receiving network device 146 * 147 * The rule here is that we 148 * assume 802.3 if the type field is short enough to be a length. 149 * This is normal practice and works for any 'now in use' protocol. 150 */ 151 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) 152 { 153 unsigned short _service_access_point; 154 const unsigned short *sap; 155 const struct ethhdr *eth; 156 157 skb->dev = dev; 158 skb_reset_mac_header(skb); 159 skb_pull_inline(skb, ETH_HLEN); 160 eth = eth_hdr(skb); 161 162 if (unlikely(is_multicast_ether_addr(eth->h_dest))) { 163 if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast)) 164 skb->pkt_type = PACKET_BROADCAST; 165 else 166 skb->pkt_type = PACKET_MULTICAST; 167 } 168 else if (unlikely(!ether_addr_equal_64bits(eth->h_dest, 169 dev->dev_addr))) 170 skb->pkt_type = PACKET_OTHERHOST; 171 172 /* 173 * Some variants of DSA tagging don't have an ethertype field 174 * at all, so we check here whether one of those tagging 175 * variants has been configured on the receiving interface, 176 * and if so, set skb->protocol without looking at the packet. 177 */ 178 if (unlikely(netdev_uses_dsa(dev))) 179 return htons(ETH_P_XDSA); 180 181 if (likely(ntohs(eth->h_proto) >= ETH_P_802_3_MIN)) 182 return eth->h_proto; 183 184 /* 185 * This is a magic hack to spot IPX packets. Older Novell breaks 186 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 187 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 188 * won't work for fault tolerant netware but does for the rest. 189 */ 190 sap = skb_header_pointer(skb, 0, sizeof(*sap), &_service_access_point); 191 if (sap && *sap == 0xFFFF) 192 return htons(ETH_P_802_3); 193 194 /* 195 * Real 802.2 LLC 196 */ 197 return htons(ETH_P_802_2); 198 } 199 EXPORT_SYMBOL(eth_type_trans); 200 201 /** 202 * eth_header_parse - extract hardware address from packet 203 * @skb: packet to extract header from 204 * @haddr: destination buffer 205 */ 206 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr) 207 { 208 const struct ethhdr *eth = eth_hdr(skb); 209 memcpy(haddr, eth->h_source, ETH_ALEN); 210 return ETH_ALEN; 211 } 212 EXPORT_SYMBOL(eth_header_parse); 213 214 /** 215 * eth_header_cache - fill cache entry from neighbour 216 * @neigh: source neighbour 217 * @hh: destination cache entry 218 * @type: Ethernet type field 219 * 220 * Create an Ethernet header template from the neighbour. 221 */ 222 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type) 223 { 224 struct ethhdr *eth; 225 const struct net_device *dev = neigh->dev; 226 227 eth = (struct ethhdr *) 228 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 229 230 if (type == htons(ETH_P_802_3)) 231 return -1; 232 233 eth->h_proto = type; 234 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 235 memcpy(eth->h_dest, neigh->ha, ETH_ALEN); 236 hh->hh_len = ETH_HLEN; 237 return 0; 238 } 239 EXPORT_SYMBOL(eth_header_cache); 240 241 /** 242 * eth_header_cache_update - update cache entry 243 * @hh: destination cache entry 244 * @dev: network device 245 * @haddr: new hardware address 246 * 247 * Called by Address Resolution module to notify changes in address. 248 */ 249 void eth_header_cache_update(struct hh_cache *hh, 250 const struct net_device *dev, 251 const unsigned char *haddr) 252 { 253 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 254 haddr, ETH_ALEN); 255 } 256 EXPORT_SYMBOL(eth_header_cache_update); 257 258 /** 259 * eth_prepare_mac_addr_change - prepare for mac change 260 * @dev: network device 261 * @p: socket address 262 */ 263 int eth_prepare_mac_addr_change(struct net_device *dev, void *p) 264 { 265 struct sockaddr *addr = p; 266 267 if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev)) 268 return -EBUSY; 269 if (!is_valid_ether_addr(addr->sa_data)) 270 return -EADDRNOTAVAIL; 271 return 0; 272 } 273 EXPORT_SYMBOL(eth_prepare_mac_addr_change); 274 275 /** 276 * eth_commit_mac_addr_change - commit mac change 277 * @dev: network device 278 * @p: socket address 279 */ 280 void eth_commit_mac_addr_change(struct net_device *dev, void *p) 281 { 282 struct sockaddr *addr = p; 283 284 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); 285 } 286 EXPORT_SYMBOL(eth_commit_mac_addr_change); 287 288 /** 289 * eth_mac_addr - set new Ethernet hardware address 290 * @dev: network device 291 * @p: socket address 292 * 293 * Change hardware address of device. 294 * 295 * This doesn't change hardware matching, so needs to be overridden 296 * for most real devices. 297 */ 298 int eth_mac_addr(struct net_device *dev, void *p) 299 { 300 int ret; 301 302 ret = eth_prepare_mac_addr_change(dev, p); 303 if (ret < 0) 304 return ret; 305 eth_commit_mac_addr_change(dev, p); 306 return 0; 307 } 308 EXPORT_SYMBOL(eth_mac_addr); 309 310 /** 311 * eth_change_mtu - set new MTU size 312 * @dev: network device 313 * @new_mtu: new Maximum Transfer Unit 314 * 315 * Allow changing MTU size. Needs to be overridden for devices 316 * supporting jumbo frames. 317 */ 318 int eth_change_mtu(struct net_device *dev, int new_mtu) 319 { 320 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 321 return -EINVAL; 322 dev->mtu = new_mtu; 323 return 0; 324 } 325 EXPORT_SYMBOL(eth_change_mtu); 326 327 int eth_validate_addr(struct net_device *dev) 328 { 329 if (!is_valid_ether_addr(dev->dev_addr)) 330 return -EADDRNOTAVAIL; 331 332 return 0; 333 } 334 EXPORT_SYMBOL(eth_validate_addr); 335 336 const struct header_ops eth_header_ops ____cacheline_aligned = { 337 .create = eth_header, 338 .parse = eth_header_parse, 339 .cache = eth_header_cache, 340 .cache_update = eth_header_cache_update, 341 }; 342 343 /** 344 * ether_setup - setup Ethernet network device 345 * @dev: network device 346 * 347 * Fill in the fields of the device structure with Ethernet-generic values. 348 */ 349 void ether_setup(struct net_device *dev) 350 { 351 dev->header_ops = ð_header_ops; 352 dev->type = ARPHRD_ETHER; 353 dev->hard_header_len = ETH_HLEN; 354 dev->mtu = ETH_DATA_LEN; 355 dev->addr_len = ETH_ALEN; 356 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 357 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 358 dev->priv_flags |= IFF_TX_SKB_SHARING; 359 360 eth_broadcast_addr(dev->broadcast); 361 362 } 363 EXPORT_SYMBOL(ether_setup); 364 365 /** 366 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device 367 * @sizeof_priv: Size of additional driver-private structure to be allocated 368 * for this Ethernet device 369 * @txqs: The number of TX queues this device has. 370 * @rxqs: The number of RX queues this device has. 371 * 372 * Fill in the fields of the device structure with Ethernet-generic 373 * values. Basically does everything except registering the device. 374 * 375 * Constructs a new net device, complete with a private data area of 376 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for 377 * this private data area. 378 */ 379 380 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs, 381 unsigned int rxqs) 382 { 383 return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_UNKNOWN, 384 ether_setup, txqs, rxqs); 385 } 386 EXPORT_SYMBOL(alloc_etherdev_mqs); 387 388 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len) 389 { 390 return scnprintf(buf, PAGE_SIZE, "%*phC\n", len, addr); 391 } 392 EXPORT_SYMBOL(sysfs_format_mac); 393 394 struct sk_buff **eth_gro_receive(struct sk_buff **head, 395 struct sk_buff *skb) 396 { 397 struct sk_buff *p, **pp = NULL; 398 struct ethhdr *eh, *eh2; 399 unsigned int hlen, off_eth; 400 const struct packet_offload *ptype; 401 __be16 type; 402 int flush = 1; 403 404 off_eth = skb_gro_offset(skb); 405 hlen = off_eth + sizeof(*eh); 406 eh = skb_gro_header_fast(skb, off_eth); 407 if (skb_gro_header_hard(skb, hlen)) { 408 eh = skb_gro_header_slow(skb, hlen, off_eth); 409 if (unlikely(!eh)) 410 goto out; 411 } 412 413 flush = 0; 414 415 for (p = *head; p; p = p->next) { 416 if (!NAPI_GRO_CB(p)->same_flow) 417 continue; 418 419 eh2 = (struct ethhdr *)(p->data + off_eth); 420 if (compare_ether_header(eh, eh2)) { 421 NAPI_GRO_CB(p)->same_flow = 0; 422 continue; 423 } 424 } 425 426 type = eh->h_proto; 427 428 rcu_read_lock(); 429 ptype = gro_find_receive_by_type(type); 430 if (ptype == NULL) { 431 flush = 1; 432 goto out_unlock; 433 } 434 435 skb_gro_pull(skb, sizeof(*eh)); 436 skb_gro_postpull_rcsum(skb, eh, sizeof(*eh)); 437 pp = ptype->callbacks.gro_receive(head, skb); 438 439 out_unlock: 440 rcu_read_unlock(); 441 out: 442 NAPI_GRO_CB(skb)->flush |= flush; 443 444 return pp; 445 } 446 EXPORT_SYMBOL(eth_gro_receive); 447 448 int eth_gro_complete(struct sk_buff *skb, int nhoff) 449 { 450 struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff); 451 __be16 type = eh->h_proto; 452 struct packet_offload *ptype; 453 int err = -ENOSYS; 454 455 if (skb->encapsulation) 456 skb_set_inner_mac_header(skb, nhoff); 457 458 rcu_read_lock(); 459 ptype = gro_find_complete_by_type(type); 460 if (ptype != NULL) 461 err = ptype->callbacks.gro_complete(skb, nhoff + 462 sizeof(struct ethhdr)); 463 464 rcu_read_unlock(); 465 return err; 466 } 467 EXPORT_SYMBOL(eth_gro_complete); 468 469 static struct packet_offload eth_packet_offload __read_mostly = { 470 .type = cpu_to_be16(ETH_P_TEB), 471 .callbacks = { 472 .gro_receive = eth_gro_receive, 473 .gro_complete = eth_gro_complete, 474 }, 475 }; 476 477 static int __init eth_offload_init(void) 478 { 479 dev_add_offload(ð_packet_offload); 480 481 return 0; 482 } 483 484 fs_initcall(eth_offload_init); 485