eth.c 9.1 KB

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  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. __setup("ether=", netdev_boot_setup);
  63. /**
  64. * eth_header - create the Ethernet header
  65. * @skb: buffer to alter
  66. * @dev: source device
  67. * @type: Ethernet type field
  68. * @daddr: destination address (NULL leave destination address)
  69. * @saddr: source address (NULL use device source address)
  70. * @len: packet length (<= skb->len)
  71. *
  72. *
  73. * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
  74. * in here instead. It is up to the 802.2 layer to carry protocol information.
  75. */
  76. int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
  77. void *daddr, void *saddr, unsigned len)
  78. {
  79. struct ethhdr *eth = (struct ethhdr *)skb_push(skb, ETH_HLEN);
  80. if (type != ETH_P_802_3)
  81. eth->h_proto = htons(type);
  82. else
  83. eth->h_proto = htons(len);
  84. /*
  85. * Set the source hardware address.
  86. */
  87. if (!saddr)
  88. saddr = dev->dev_addr;
  89. memcpy(eth->h_source, saddr, dev->addr_len);
  90. if (daddr) {
  91. memcpy(eth->h_dest, daddr, dev->addr_len);
  92. return ETH_HLEN;
  93. }
  94. /*
  95. * Anyway, the loopback-device should never use this function...
  96. */
  97. if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
  98. memset(eth->h_dest, 0, dev->addr_len);
  99. return ETH_HLEN;
  100. }
  101. return -ETH_HLEN;
  102. }
  103. /**
  104. * eth_rebuild_header- rebuild the Ethernet MAC header.
  105. * @skb: socket buffer to update
  106. *
  107. * This is called after an ARP or IPV6 ndisc it's resolution on this
  108. * sk_buff. We now let protocol (ARP) fill in the other fields.
  109. *
  110. * This routine CANNOT use cached dst->neigh!
  111. * Really, it is used only when dst->neigh is wrong.
  112. */
  113. int eth_rebuild_header(struct sk_buff *skb)
  114. {
  115. struct ethhdr *eth = (struct ethhdr *)skb->data;
  116. struct net_device *dev = skb->dev;
  117. switch (eth->h_proto) {
  118. #ifdef CONFIG_INET
  119. case __constant_htons(ETH_P_IP):
  120. return arp_find(eth->h_dest, skb);
  121. #endif
  122. default:
  123. printk(KERN_DEBUG
  124. "%s: unable to resolve type %X addresses.\n",
  125. dev->name, (int)eth->h_proto);
  126. memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
  127. break;
  128. }
  129. return 0;
  130. }
  131. /**
  132. * eth_type_trans - determine the packet's protocol ID.
  133. * @skb: received socket data
  134. * @dev: receiving network device
  135. *
  136. * The rule here is that we
  137. * assume 802.3 if the type field is short enough to be a length.
  138. * This is normal practice and works for any 'now in use' protocol.
  139. */
  140. __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
  141. {
  142. struct ethhdr *eth;
  143. unsigned char *rawp;
  144. skb->mac.raw = skb->data;
  145. skb_pull(skb, ETH_HLEN);
  146. eth = eth_hdr(skb);
  147. if (is_multicast_ether_addr(eth->h_dest)) {
  148. if (!compare_ether_addr(eth->h_dest, dev->broadcast))
  149. skb->pkt_type = PACKET_BROADCAST;
  150. else
  151. skb->pkt_type = PACKET_MULTICAST;
  152. }
  153. /*
  154. * This ALLMULTI check should be redundant by 1.4
  155. * so don't forget to remove it.
  156. *
  157. * Seems, you forgot to remove it. All silly devices
  158. * seems to set IFF_PROMISC.
  159. */
  160. else if (1 /*dev->flags&IFF_PROMISC */ ) {
  161. if (unlikely(compare_ether_addr(eth->h_dest, dev->dev_addr)))
  162. skb->pkt_type = PACKET_OTHERHOST;
  163. }
  164. if (ntohs(eth->h_proto) >= 1536)
  165. return eth->h_proto;
  166. rawp = skb->data;
  167. /*
  168. * This is a magic hack to spot IPX packets. Older Novell breaks
  169. * the protocol design and runs IPX over 802.3 without an 802.2 LLC
  170. * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
  171. * won't work for fault tolerant netware but does for the rest.
  172. */
  173. if (*(unsigned short *)rawp == 0xFFFF)
  174. return htons(ETH_P_802_3);
  175. /*
  176. * Real 802.2 LLC
  177. */
  178. return htons(ETH_P_802_2);
  179. }
  180. EXPORT_SYMBOL(eth_type_trans);
  181. /**
  182. * eth_header_parse - extract hardware address from packet
  183. * @skb: packet to extract header from
  184. * @haddr: destination buffer
  185. */
  186. static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr)
  187. {
  188. struct ethhdr *eth = eth_hdr(skb);
  189. memcpy(haddr, eth->h_source, ETH_ALEN);
  190. return ETH_ALEN;
  191. }
  192. /**
  193. * eth_header_cache - fill cache entry from neighbour
  194. * @neigh: source neighbour
  195. * @hh: destination cache entry
  196. * Create an Ethernet header template from the neighbour.
  197. */
  198. int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh)
  199. {
  200. __be16 type = hh->hh_type;
  201. struct ethhdr *eth;
  202. struct net_device *dev = neigh->dev;
  203. eth = (struct ethhdr *)
  204. (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
  205. if (type == __constant_htons(ETH_P_802_3))
  206. return -1;
  207. eth->h_proto = type;
  208. memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
  209. memcpy(eth->h_dest, neigh->ha, dev->addr_len);
  210. hh->hh_len = ETH_HLEN;
  211. return 0;
  212. }
  213. /**
  214. * eth_header_cache_update - update cache entry
  215. * @hh: destination cache entry
  216. * @dev: network device
  217. * @haddr: new hardware address
  218. *
  219. * Called by Address Resolution module to notify changes in address.
  220. */
  221. void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev,
  222. unsigned char *haddr)
  223. {
  224. memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
  225. haddr, dev->addr_len);
  226. }
  227. /**
  228. * eth_mac_addr - set new Ethernet hardware address
  229. * @dev: network device
  230. * @p: socket address
  231. * Change hardware address of device.
  232. *
  233. * This doesn't change hardware matching, so needs to be overridden
  234. * for most real devices.
  235. */
  236. static int eth_mac_addr(struct net_device *dev, void *p)
  237. {
  238. struct sockaddr *addr = p;
  239. if (netif_running(dev))
  240. return -EBUSY;
  241. memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
  242. return 0;
  243. }
  244. /**
  245. * eth_change_mtu - set new MTU size
  246. * @dev: network device
  247. * @new_mtu: new Maximum Transfer Unit
  248. *
  249. * Allow changing MTU size. Needs to be overridden for devices
  250. * supporting jumbo frames.
  251. */
  252. static int eth_change_mtu(struct net_device *dev, int new_mtu)
  253. {
  254. if (new_mtu < 68 || new_mtu > ETH_DATA_LEN)
  255. return -EINVAL;
  256. dev->mtu = new_mtu;
  257. return 0;
  258. }
  259. /**
  260. * ether_setup - setup Ethernet network device
  261. * @dev: network device
  262. * Fill in the fields of the device structure with Ethernet-generic values.
  263. */
  264. void ether_setup(struct net_device *dev)
  265. {
  266. dev->change_mtu = eth_change_mtu;
  267. dev->hard_header = eth_header;
  268. dev->rebuild_header = eth_rebuild_header;
  269. dev->set_mac_address = eth_mac_addr;
  270. dev->hard_header_cache = eth_header_cache;
  271. dev->header_cache_update= eth_header_cache_update;
  272. dev->hard_header_parse = eth_header_parse;
  273. dev->type = ARPHRD_ETHER;
  274. dev->hard_header_len = ETH_HLEN;
  275. dev->mtu = ETH_DATA_LEN;
  276. dev->addr_len = ETH_ALEN;
  277. dev->tx_queue_len = 1000; /* Ethernet wants good queues */
  278. dev->flags = IFF_BROADCAST|IFF_MULTICAST;
  279. memset(dev->broadcast, 0xFF, ETH_ALEN);
  280. }
  281. EXPORT_SYMBOL(ether_setup);
  282. /**
  283. * alloc_etherdev - Allocates and sets up an Ethernet device
  284. * @sizeof_priv: Size of additional driver-private structure to be allocated
  285. * for this Ethernet device
  286. *
  287. * Fill in the fields of the device structure with Ethernet-generic
  288. * values. Basically does everything except registering the device.
  289. *
  290. * Constructs a new net device, complete with a private data area of
  291. * size (sizeof_priv). A 32-byte (not bit) alignment is enforced for
  292. * this private data area.
  293. */
  294. struct net_device *alloc_etherdev(int sizeof_priv)
  295. {
  296. return alloc_netdev(sizeof_priv, "eth%d", ether_setup);
  297. }
  298. EXPORT_SYMBOL(alloc_etherdev);