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 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 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 memset(eth->h_dest, 0, ETH_ALEN); 108 return ETH_HLEN; 109 } 110 111 return -ETH_HLEN; 112 } 113 EXPORT_SYMBOL(eth_header); 114 115 /** 116 * eth_rebuild_header- rebuild the Ethernet MAC header. 117 * @skb: socket buffer to update 118 * 119 * This is called after an ARP or IPV6 ndisc it's resolution on this 120 * sk_buff. We now let protocol (ARP) fill in the other fields. 121 * 122 * This routine CANNOT use cached dst->neigh! 123 * Really, it is used only when dst->neigh is wrong. 124 */ 125 int eth_rebuild_header(struct sk_buff *skb) 126 { 127 struct ethhdr *eth = (struct ethhdr *)skb->data; 128 struct net_device *dev = skb->dev; 129 130 switch (eth->h_proto) { 131 #ifdef CONFIG_INET 132 case htons(ETH_P_IP): 133 return arp_find(eth->h_dest, skb); 134 #endif 135 default: 136 printk(KERN_DEBUG 137 "%s: unable to resolve type %X addresses.\n", 138 dev->name, ntohs(eth->h_proto)); 139 140 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 141 break; 142 } 143 144 return 0; 145 } 146 EXPORT_SYMBOL(eth_rebuild_header); 147 148 /** 149 * eth_type_trans - determine the packet's protocol ID. 150 * @skb: received socket data 151 * @dev: receiving network device 152 * 153 * The rule here is that we 154 * assume 802.3 if the type field is short enough to be a length. 155 * This is normal practice and works for any 'now in use' protocol. 156 */ 157 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) 158 { 159 struct ethhdr *eth; 160 161 skb->dev = dev; 162 skb_reset_mac_header(skb); 163 skb_pull_inline(skb, ETH_HLEN); 164 eth = eth_hdr(skb); 165 166 if (unlikely(is_multicast_ether_addr(eth->h_dest))) { 167 if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast)) 168 skb->pkt_type = PACKET_BROADCAST; 169 else 170 skb->pkt_type = PACKET_MULTICAST; 171 } 172 173 /* 174 * This ALLMULTI check should be redundant by 1.4 175 * so don't forget to remove it. 176 * 177 * Seems, you forgot to remove it. All silly devices 178 * seems to set IFF_PROMISC. 179 */ 180 181 else if (1 /*dev->flags&IFF_PROMISC */ ) { 182 if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr))) 183 skb->pkt_type = PACKET_OTHERHOST; 184 } 185 186 /* 187 * Some variants of DSA tagging don't have an ethertype field 188 * at all, so we check here whether one of those tagging 189 * variants has been configured on the receiving interface, 190 * and if so, set skb->protocol without looking at the packet. 191 */ 192 if (netdev_uses_dsa_tags(dev)) 193 return htons(ETH_P_DSA); 194 if (netdev_uses_trailer_tags(dev)) 195 return htons(ETH_P_TRAILER); 196 197 if (ntohs(eth->h_proto) >= 1536) 198 return eth->h_proto; 199 200 /* 201 * This is a magic hack to spot IPX packets. Older Novell breaks 202 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 203 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 204 * won't work for fault tolerant netware but does for the rest. 205 */ 206 if (skb->len >= 2 && *(unsigned short *)(skb->data) == 0xFFFF) 207 return htons(ETH_P_802_3); 208 209 /* 210 * Real 802.2 LLC 211 */ 212 return htons(ETH_P_802_2); 213 } 214 EXPORT_SYMBOL(eth_type_trans); 215 216 /** 217 * eth_header_parse - extract hardware address from packet 218 * @skb: packet to extract header from 219 * @haddr: destination buffer 220 */ 221 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr) 222 { 223 const struct ethhdr *eth = eth_hdr(skb); 224 memcpy(haddr, eth->h_source, ETH_ALEN); 225 return ETH_ALEN; 226 } 227 EXPORT_SYMBOL(eth_header_parse); 228 229 /** 230 * eth_header_cache - fill cache entry from neighbour 231 * @neigh: source neighbour 232 * @hh: destination cache entry 233 * @type: Ethernet type field 234 * Create an Ethernet header template from the neighbour. 235 */ 236 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type) 237 { 238 struct ethhdr *eth; 239 const struct net_device *dev = neigh->dev; 240 241 eth = (struct ethhdr *) 242 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 243 244 if (type == htons(ETH_P_802_3)) 245 return -1; 246 247 eth->h_proto = type; 248 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 249 memcpy(eth->h_dest, neigh->ha, ETH_ALEN); 250 hh->hh_len = ETH_HLEN; 251 return 0; 252 } 253 EXPORT_SYMBOL(eth_header_cache); 254 255 /** 256 * eth_header_cache_update - update cache entry 257 * @hh: destination cache entry 258 * @dev: network device 259 * @haddr: new hardware address 260 * 261 * Called by Address Resolution module to notify changes in address. 262 */ 263 void eth_header_cache_update(struct hh_cache *hh, 264 const struct net_device *dev, 265 const unsigned char *haddr) 266 { 267 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 268 haddr, ETH_ALEN); 269 } 270 EXPORT_SYMBOL(eth_header_cache_update); 271 272 /** 273 * eth_mac_addr - set new Ethernet hardware address 274 * @dev: network device 275 * @p: socket address 276 * Change hardware address of device. 277 * 278 * This doesn't change hardware matching, so needs to be overridden 279 * for most real devices. 280 */ 281 int eth_mac_addr(struct net_device *dev, void *p) 282 { 283 struct sockaddr *addr = p; 284 285 if (netif_running(dev)) 286 return -EBUSY; 287 if (!is_valid_ether_addr(addr->sa_data)) 288 return -EADDRNOTAVAIL; 289 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); 290 /* if device marked as NET_ADDR_RANDOM, reset it */ 291 dev->addr_assign_type &= ~NET_ADDR_RANDOM; 292 return 0; 293 } 294 EXPORT_SYMBOL(eth_mac_addr); 295 296 /** 297 * eth_change_mtu - set new MTU size 298 * @dev: network device 299 * @new_mtu: new Maximum Transfer Unit 300 * 301 * Allow changing MTU size. Needs to be overridden for devices 302 * supporting jumbo frames. 303 */ 304 int eth_change_mtu(struct net_device *dev, int new_mtu) 305 { 306 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 307 return -EINVAL; 308 dev->mtu = new_mtu; 309 return 0; 310 } 311 EXPORT_SYMBOL(eth_change_mtu); 312 313 int eth_validate_addr(struct net_device *dev) 314 { 315 if (!is_valid_ether_addr(dev->dev_addr)) 316 return -EADDRNOTAVAIL; 317 318 return 0; 319 } 320 EXPORT_SYMBOL(eth_validate_addr); 321 322 const struct header_ops eth_header_ops ____cacheline_aligned = { 323 .create = eth_header, 324 .parse = eth_header_parse, 325 .rebuild = eth_rebuild_header, 326 .cache = eth_header_cache, 327 .cache_update = eth_header_cache_update, 328 }; 329 330 /** 331 * ether_setup - setup Ethernet network device 332 * @dev: network device 333 * Fill in the fields of the device structure with Ethernet-generic values. 334 */ 335 void ether_setup(struct net_device *dev) 336 { 337 dev->header_ops = ð_header_ops; 338 dev->type = ARPHRD_ETHER; 339 dev->hard_header_len = ETH_HLEN; 340 dev->mtu = ETH_DATA_LEN; 341 dev->addr_len = ETH_ALEN; 342 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 343 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 344 dev->priv_flags |= IFF_TX_SKB_SHARING; 345 346 memset(dev->broadcast, 0xFF, ETH_ALEN); 347 348 } 349 EXPORT_SYMBOL(ether_setup); 350 351 /** 352 * alloc_etherdev_mqs - Allocates and sets up an Ethernet device 353 * @sizeof_priv: Size of additional driver-private structure to be allocated 354 * for this Ethernet device 355 * @txqs: The number of TX queues this device has. 356 * @rxqs: The number of RX queues this device has. 357 * 358 * Fill in the fields of the device structure with Ethernet-generic 359 * values. Basically does everything except registering the device. 360 * 361 * Constructs a new net device, complete with a private data area of 362 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for 363 * this private data area. 364 */ 365 366 struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs, 367 unsigned int rxqs) 368 { 369 return alloc_netdev_mqs(sizeof_priv, "eth%d", ether_setup, txqs, rxqs); 370 } 371 EXPORT_SYMBOL(alloc_etherdev_mqs); 372 373 static size_t _format_mac_addr(char *buf, int buflen, 374 const unsigned char *addr, int len) 375 { 376 int i; 377 char *cp = buf; 378 379 for (i = 0; i < len; i++) { 380 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]); 381 if (i == len - 1) 382 break; 383 cp += scnprintf(cp, buflen - (cp - buf), ":"); 384 } 385 return cp - buf; 386 } 387 388 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len) 389 { 390 size_t l; 391 392 l = _format_mac_addr(buf, PAGE_SIZE, addr, len); 393 l += scnprintf(buf + l, PAGE_SIZE - l, "\n"); 394 return (ssize_t)l; 395 } 396 EXPORT_SYMBOL(sysfs_format_mac); 397