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 <asm/uaccess.h> 61 #include <asm/system.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 we put the length 76 * in here instead. It is up to the 802.2 layer to carry protocol information. 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) 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 __constant_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, (int)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 unsigned char *rawp; 161 162 skb->dev = dev; 163 skb_reset_mac_header(skb); 164 skb_pull(skb, ETH_HLEN); 165 eth = eth_hdr(skb); 166 167 if (is_multicast_ether_addr(eth->h_dest)) { 168 if (!compare_ether_addr(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(eth->h_dest, dev->dev_addr))) 184 skb->pkt_type = PACKET_OTHERHOST; 185 } 186 187 if (ntohs(eth->h_proto) >= 1536) 188 return eth->h_proto; 189 190 rawp = skb->data; 191 192 /* 193 * This is a magic hack to spot IPX packets. Older Novell breaks 194 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 195 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 196 * won't work for fault tolerant netware but does for the rest. 197 */ 198 if (*(unsigned short *)rawp == 0xFFFF) 199 return htons(ETH_P_802_3); 200 201 /* 202 * Real 802.2 LLC 203 */ 204 return htons(ETH_P_802_2); 205 } 206 EXPORT_SYMBOL(eth_type_trans); 207 208 /** 209 * eth_header_parse - extract hardware address from packet 210 * @skb: packet to extract header from 211 * @haddr: destination buffer 212 */ 213 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr) 214 { 215 const struct ethhdr *eth = eth_hdr(skb); 216 memcpy(haddr, eth->h_source, ETH_ALEN); 217 return ETH_ALEN; 218 } 219 EXPORT_SYMBOL(eth_header_parse); 220 221 /** 222 * eth_header_cache - fill cache entry from neighbour 223 * @neigh: source neighbour 224 * @hh: destination cache entry 225 * Create an Ethernet header template from the neighbour. 226 */ 227 int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh) 228 { 229 __be16 type = hh->hh_type; 230 struct ethhdr *eth; 231 const struct net_device *dev = neigh->dev; 232 233 eth = (struct ethhdr *) 234 (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 235 236 if (type == htons(ETH_P_802_3)) 237 return -1; 238 239 eth->h_proto = type; 240 memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); 241 memcpy(eth->h_dest, neigh->ha, ETH_ALEN); 242 hh->hh_len = ETH_HLEN; 243 return 0; 244 } 245 EXPORT_SYMBOL(eth_header_cache); 246 247 /** 248 * eth_header_cache_update - update cache entry 249 * @hh: destination cache entry 250 * @dev: network device 251 * @haddr: new hardware address 252 * 253 * Called by Address Resolution module to notify changes in address. 254 */ 255 void eth_header_cache_update(struct hh_cache *hh, 256 const struct net_device *dev, 257 const unsigned char *haddr) 258 { 259 memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 260 haddr, ETH_ALEN); 261 } 262 EXPORT_SYMBOL(eth_header_cache_update); 263 264 /** 265 * eth_mac_addr - set new Ethernet hardware address 266 * @dev: network device 267 * @p: socket address 268 * Change hardware address of device. 269 * 270 * This doesn't change hardware matching, so needs to be overridden 271 * for most real devices. 272 */ 273 static int eth_mac_addr(struct net_device *dev, void *p) 274 { 275 struct sockaddr *addr = p; 276 277 if (netif_running(dev)) 278 return -EBUSY; 279 if (!is_valid_ether_addr(addr->sa_data)) 280 return -EADDRNOTAVAIL; 281 memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN); 282 return 0; 283 } 284 285 /** 286 * eth_change_mtu - set new MTU size 287 * @dev: network device 288 * @new_mtu: new Maximum Transfer Unit 289 * 290 * Allow changing MTU size. Needs to be overridden for devices 291 * supporting jumbo frames. 292 */ 293 static int eth_change_mtu(struct net_device *dev, int new_mtu) 294 { 295 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 296 return -EINVAL; 297 dev->mtu = new_mtu; 298 return 0; 299 } 300 301 static int eth_validate_addr(struct net_device *dev) 302 { 303 if (!is_valid_ether_addr(dev->dev_addr)) 304 return -EADDRNOTAVAIL; 305 306 return 0; 307 } 308 309 const struct header_ops eth_header_ops ____cacheline_aligned = { 310 .create = eth_header, 311 .parse = eth_header_parse, 312 .rebuild = eth_rebuild_header, 313 .cache = eth_header_cache, 314 .cache_update = eth_header_cache_update, 315 }; 316 317 /** 318 * ether_setup - setup Ethernet network device 319 * @dev: network device 320 * Fill in the fields of the device structure with Ethernet-generic values. 321 */ 322 void ether_setup(struct net_device *dev) 323 { 324 dev->header_ops = ð_header_ops; 325 326 dev->change_mtu = eth_change_mtu; 327 dev->set_mac_address = eth_mac_addr; 328 dev->validate_addr = eth_validate_addr; 329 330 dev->type = ARPHRD_ETHER; 331 dev->hard_header_len = ETH_HLEN; 332 dev->mtu = ETH_DATA_LEN; 333 dev->addr_len = ETH_ALEN; 334 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 335 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 336 337 memset(dev->broadcast, 0xFF, ETH_ALEN); 338 339 } 340 EXPORT_SYMBOL(ether_setup); 341 342 /** 343 * alloc_etherdev_mq - Allocates and sets up an Ethernet device 344 * @sizeof_priv: Size of additional driver-private structure to be allocated 345 * for this Ethernet device 346 * @queue_count: The number of queues this device has. 347 * 348 * Fill in the fields of the device structure with Ethernet-generic 349 * values. Basically does everything except registering the device. 350 * 351 * Constructs a new net device, complete with a private data area of 352 * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for 353 * this private data area. 354 */ 355 356 struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count) 357 { 358 return alloc_netdev_mq(sizeof_priv, "eth%d", ether_setup, queue_count); 359 } 360 EXPORT_SYMBOL(alloc_etherdev_mq); 361 362 static size_t _format_mac_addr(char *buf, int buflen, 363 const unsigned char *addr, int len) 364 { 365 int i; 366 char *cp = buf; 367 368 for (i = 0; i < len; i++) { 369 cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]); 370 if (i == len - 1) 371 break; 372 cp += strlcpy(cp, ":", buflen - (cp - buf)); 373 } 374 return cp - buf; 375 } 376 377 ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len) 378 { 379 size_t l; 380 381 l = _format_mac_addr(buf, PAGE_SIZE, addr, len); 382 l += strlcpy(buf + l, "\n", PAGE_SIZE - l); 383 return ((ssize_t) l); 384 } 385 EXPORT_SYMBOL(sysfs_format_mac); 386 387 char *print_mac(char *buf, const unsigned char *addr) 388 { 389 _format_mac_addr(buf, MAC_BUF_SIZE, addr, ETH_ALEN); 390 return buf; 391 } 392 EXPORT_SYMBOL(print_mac); 393