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 <asm/uaccess.h> 62 #include <asm/system.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 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 memset(eth->h_dest, 0, ETH_ALEN); 109 return ETH_HLEN; 110 } 111 112 return -ETH_HLEN; 113 } 114 EXPORT_SYMBOL(eth_header); 115 116 /** 117 * eth_rebuild_header- rebuild the Ethernet MAC header. 118 * @skb: socket buffer to update 119 * 120 * This is called after an ARP or IPV6 ndisc it's resolution on this 121 * sk_buff. We now let protocol (ARP) fill in the other fields. 122 * 123 * This routine CANNOT use cached dst->neigh! 124 * Really, it is used only when dst->neigh is wrong. 125 */ 126 int eth_rebuild_header(struct sk_buff *skb) 127 { 128 struct ethhdr *eth = (struct ethhdr *)skb->data; 129 struct net_device *dev = skb->dev; 130 131 switch (eth->h_proto) { 132 #ifdef CONFIG_INET 133 case htons(ETH_P_IP): 134 return arp_find(eth->h_dest, skb); 135 #endif 136 default: 137 printk(KERN_DEBUG 138 "%s: unable to resolve type %X addresses.\n", 139 dev->name, ntohs(eth->h_proto)); 140 141 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 142 break; 143 } 144 145 return 0; 146 } 147 EXPORT_SYMBOL(eth_rebuild_header); 148 149 /** 150 * eth_type_trans - determine the packet's protocol ID. 151 * @skb: received socket data 152 * @dev: receiving network device 153 * 154 * The rule here is that we 155 * assume 802.3 if the type field is short enough to be a length. 156 * This is normal practice and works for any 'now in use' protocol. 157 */ 158 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) 159 { 160 struct ethhdr *eth; 161 162 skb->dev = dev; 163 skb_reset_mac_header(skb); 164 skb_pull_inline(skb, ETH_HLEN); 165 eth = eth_hdr(skb); 166 167 if (unlikely(is_multicast_ether_addr(eth->h_dest))) { 168 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast)) 169 skb->pkt_type = PACKET_BROADCAST; 170 else 171 skb->pkt_type = PACKET_MULTICAST; 172 } 173 174 /* 175 * This ALLMULTI check should be redundant by 1.4 176 * so don't forget to remove it. 177 * 178 * Seems, you forgot to remove it. All silly devices 179 * seems to set IFF_PROMISC. 180 */ 181 182 else if (1 /*dev->flags&IFF_PROMISC */ ) { 183 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr))) 184 skb->pkt_type = PACKET_OTHERHOST; 185 } 186 187 /* 188 * Some variants of DSA tagging don't have an ethertype field 189 * at all, so we check here whether one of those tagging 190 * variants has been configured on the receiving interface, 191 * and if so, set skb->protocol without looking at the packet. 192 */ 193 if (netdev_uses_dsa_tags(dev)) 194 return htons(ETH_P_DSA); 195 if (netdev_uses_trailer_tags(dev)) 196 return htons(ETH_P_TRAILER); 197 198 if (ntohs(eth->h_proto) >= 1536) 199 return eth->h_proto; 200 201 /* 202 * This is a magic hack to spot IPX packets. Older Novell breaks 203 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 204 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 205 * won't work for fault tolerant netware but does for the rest. 206 */ 207 if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF) 208 return htons(ETH_P_802_3); 209 210 /* 211 * Real 802.2 LLC 212 */ 213 return htons(ETH_P_802_2); 214 } 215 EXPORT_SYMBOL(eth_type_trans); 216 217 /** 218 * eth_header_parse - extract hardware address from packet 219 * @skb: packet to extract header from 220 * @haddr: destination buffer 221 */ 222 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr) 223 { 224 const struct ethhdr *eth = eth_hdr(skb); 225 memcpy(haddr, eth->h_source, ETH_ALEN); 226 return ETH_ALEN; 227 } 228 EXPORT_SYMBOL(eth_header_parse); 229 230 /** 231 * eth_header_cache - fill cache entry from neighbour 232 * @neigh: source neighbour 233 * @hh: destination cache entry 234 * @type: Ethernet type field 235 * Create an Ethernet header template from the neighbour. 236 */ 237 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type) 238 { 239 struct ethhdr *eth; 240 const struct net_device *dev = neigh->dev; 241 242 eth = (struct ethhdr *) 243 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 244 245 if (type == htons(ETH_P_802_3)) 246 return -1; 247 248 eth->h_proto = type; 249 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 250 memcpy(eth->h_dest, neigh->ha, ETH_ALEN); 251 hh->hh_len = ETH_HLEN; 252 return 0; 253 } 254 EXPORT_SYMBOL(eth_header_cache); 255 256 /** 257 * eth_header_cache_update - update cache entry 258 * @hh: destination cache entry 259 * @dev: network device 260 * @haddr: new hardware address 261 * 262 * Called by Address Resolution module to notify changes in address. 263 */ 264 void eth_header_cache_update(struct hh_cache *hh, 265 const struct net_device *dev, 266 const unsigned char *haddr) 267 { 268 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 269 haddr, ETH_ALEN); 270 } 271 EXPORT_SYMBOL(eth_header_cache_update); 272 273 /** 274 * eth_mac_addr - set new Ethernet hardware address 275 * @dev: network device 276 * @p: socket address 277 * Change hardware address of device. 278 * 279 * This doesn't change hardware matching, so needs to be overridden 280 * for most real devices. 281 */ 282 int eth_mac_addr(struct net_device *dev, void *p) 283 { 284 struct sockaddr *addr = p; 285 286 if (netif_running(dev)) 287 return -EBUSY; 288 if (!is_valid_ether_addr(addr->sa_data)) 289 return -EADDRNOTAVAIL; 290 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); 291 /* if device marked as NET_ADDR_RANDOM, reset it */ 292 dev->addr_assign_type &= ~NET_ADDR_RANDOM; 293 return 0; 294 } 295 EXPORT_SYMBOL(eth_mac_addr); 296 297 /** 298 * eth_change_mtu - set new MTU size 299 * @dev: network device 300 * @new_mtu: new Maximum Transfer Unit 301 * 302 * Allow changing MTU size. Needs to be overridden for devices 303 * supporting jumbo frames. 304 */ 305 int eth_change_mtu(struct net_device *dev, int new_mtu) 306 { 307 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 308 return -EINVAL; 309 dev->mtu = new_mtu; 310 return 0; 311 } 312 EXPORT_SYMBOL(eth_change_mtu); 313 314 int eth_validate_addr(struct net_device *dev) 315 { 316 if (!is_valid_ether_addr(dev->dev_addr)) 317 return -EADDRNOTAVAIL; 318 319 return 0; 320 } 321 EXPORT_SYMBOL(eth_validate_addr); 322 323 const struct header_ops eth_header_ops ____cacheline_aligned = { 324 .create = eth_header, 325 .parse = eth_header_parse, 326 .rebuild = eth_rebuild_header, 327 .cache = eth_header_cache, 328 .cache_update = eth_header_cache_update, 329 }; 330 331 /** 332 * ether_setup - setup Ethernet network device 333 * @dev: network device 334 * Fill in the fields of the device structure with Ethernet-generic values. 335 */ 336 void ether_setup(struct net_device *dev) 337 { 338 dev->header_ops = ð_header_ops; 339 dev->type = ARPHRD_ETHER; 340 dev->hard_header_len = ETH_HLEN; 341 dev->mtu = ETH_DATA_LEN; 342 dev->addr_len = ETH_ALEN; 343 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 344 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 345 dev->priv_flags |= IFF_TX_SKB_SHARING; 346 347 memset(dev->broadcast, 0xFF, ETH_ALEN); 348 349 } 350 EXPORT_SYMBOL(ether_setup); 351 352 /** 353 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device 354 * @sizeof_priv: Size of additional driver-private structure to be allocated 355 * for this Ethernet device 356 * @txqs: The number of TX queues this device has. 357 * @rxqs: The number of RX queues this device has. 358 * 359 * Fill in the fields of the device structure with Ethernet-generic 360 * values. Basically does everything except registering the device. 361 * 362 * Constructs a new net device, complete with a private data area of 363 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for 364 * this private data area. 365 */ 366 367 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs, 368 unsigned int rxqs) 369 { 370 return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs); 371 } 372 EXPORT_SYMBOL(alloc_etherdev_mqs); 373 374 static size_t _format_mac_addr(char *buf, int buflen, 375 const unsigned char *addr, int len) 376 { 377 int i; 378 char *cp = buf; 379 380 for (i = 0; i < len; i++) { 381 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]); 382 if (i == len - 1) 383 break; 384 cp += scnprintf(cp, buflen - (cp - buf), ":"); 385 } 386 return cp - buf; 387 } 388 389 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len) 390 { 391 size_t l; 392 393 l = _format_mac_addr(buf, PAGE_SIZE, addr, len); 394 l += scnprintf(buf + l, PAGE_SIZE - l, "\n"); 395 return (ssize_t)l; 396 } 397 EXPORT_SYMBOL(sysfs_format_mac); 398