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/sched.h> 44 #include <linux/string.h> 45 #include <linux/mm.h> 46 #include <linux/socket.h> 47 #include <linux/in.h> 48 #include <linux/inet.h> 49 #include <linux/ip.h> 50 #include <linux/netdevice.h> 51 #include <linux/etherdevice.h> 52 #include <linux/skbuff.h> 53 #include <linux/errno.h> 54 #include <linux/config.h> 55 #include <linux/init.h> 56 #include <linux/if_ether.h> 57 #include <net/dst.h> 58 #include <net/arp.h> 59 #include <net/sock.h> 60 #include <net/ipv6.h> 61 #include <net/ip.h> 62 #include <asm/uaccess.h> 63 #include <asm/system.h> 64 #include <asm/checksum.h> 65 66 __setup("ether=", netdev_boot_setup); 67 68 /* 69 * Create the Ethernet MAC header for an arbitrary protocol layer 70 * 71 * saddr=NULL means use device source address 72 * daddr=NULL means leave destination address (eg unresolved arp) 73 */ 74 75 int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, 76 void *daddr, void *saddr, unsigned len) 77 { 78 struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN); 79 80 /* 81 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length 82 * in here instead. It is up to the 802.2 layer to carry protocol information. 83 */ 84 85 if(type!=ETH_P_802_3) 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,dev->addr_len); 97 98 /* 99 * Anyway, the loopback-device should never use this function... 100 */ 101 102 if (dev->flags & (IFF_LOOPBACK|IFF_NOARP)) 103 { 104 memset(eth->h_dest, 0, dev->addr_len); 105 return ETH_HLEN; 106 } 107 108 if(daddr) 109 { 110 memcpy(eth->h_dest,daddr,dev->addr_len); 111 return ETH_HLEN; 112 } 113 114 return -ETH_HLEN; 115 } 116 117 118 /* 119 * Rebuild the Ethernet MAC header. This is called after an ARP 120 * (or in future other address resolution) has completed on this 121 * sk_buff. We now let 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 */ 126 127 int eth_rebuild_header(struct sk_buff *skb) 128 { 129 struct ethhdr *eth = (struct ethhdr *)skb->data; 130 struct net_device *dev = skb->dev; 131 132 switch (eth->h_proto) 133 { 134 #ifdef CONFIG_INET 135 case __constant_htons(ETH_P_IP): 136 return arp_find(eth->h_dest, skb); 137 #endif 138 default: 139 printk(KERN_DEBUG 140 "%s: unable to resolve type %X addresses.\n", 141 dev->name, (int)eth->h_proto); 142 143 memcpy(eth->h_source, dev->dev_addr, dev->addr_len); 144 break; 145 } 146 147 return 0; 148 } 149 150 151 /* 152 * Determine the packet's protocol ID. The rule here is that we 153 * assume 802.3 if the type field is short enough to be a length. 154 * This is normal practice and works for any 'now in use' protocol. 155 */ 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->mac.raw = skb->data; 163 skb_pull(skb,ETH_HLEN); 164 eth = eth_hdr(skb); 165 166 if (is_multicast_ether_addr(eth->h_dest)) { 167 if (!compare_ether_addr(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(eth->h_dest, dev->dev_addr))) 183 skb->pkt_type = PACKET_OTHERHOST; 184 } 185 186 if (ntohs(eth->h_proto) >= 1536) 187 return eth->h_proto; 188 189 rawp = skb->data; 190 191 /* 192 * This is a magic hack to spot IPX packets. Older Novell breaks 193 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 194 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 195 * won't work for fault tolerant netware but does for the rest. 196 */ 197 if (*(unsigned short *)rawp == 0xFFFF) 198 return htons(ETH_P_802_3); 199 200 /* 201 * Real 802.2 LLC 202 */ 203 return htons(ETH_P_802_2); 204 } 205 206 static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr) 207 { 208 struct ethhdr *eth = eth_hdr(skb); 209 memcpy(haddr, eth->h_source, ETH_ALEN); 210 return ETH_ALEN; 211 } 212 213 int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh) 214 { 215 unsigned short type = hh->hh_type; 216 struct ethhdr *eth; 217 struct net_device *dev = neigh->dev; 218 219 eth = (struct ethhdr*) 220 (((u8*)hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 221 222 if (type == __constant_htons(ETH_P_802_3)) 223 return -1; 224 225 eth->h_proto = type; 226 memcpy(eth->h_source, dev->dev_addr, dev->addr_len); 227 memcpy(eth->h_dest, neigh->ha, dev->addr_len); 228 hh->hh_len = ETH_HLEN; 229 return 0; 230 } 231 232 /* 233 * Called by Address Resolution module to notify changes in address. 234 */ 235 236 void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr) 237 { 238 memcpy(((u8*)hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 239 haddr, dev->addr_len); 240 } 241 242 EXPORT_SYMBOL(eth_type_trans); 243 244 static int eth_mac_addr(struct net_device *dev, void *p) 245 { 246 struct sockaddr *addr=p; 247 if (netif_running(dev)) 248 return -EBUSY; 249 memcpy(dev->dev_addr, addr->sa_data,dev->addr_len); 250 return 0; 251 } 252 253 static int eth_change_mtu(struct net_device *dev, int new_mtu) 254 { 255 if (new_mtu < 68 || new_mtu > ETH_DATA_LEN) 256 return -EINVAL; 257 dev->mtu = new_mtu; 258 return 0; 259 } 260 261 /* 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; 273 274 dev->type = ARPHRD_ETHER; 275 dev->hard_header_len = ETH_HLEN; 276 dev->mtu = ETH_DATA_LEN; 277 dev->addr_len = ETH_ALEN; 278 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 279 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 280 281 memset(dev->broadcast,0xFF, ETH_ALEN); 282 283 } 284 EXPORT_SYMBOL(ether_setup); 285 286 /** 287 * alloc_etherdev - Allocates and sets up an ethernet device 288 * @sizeof_priv: Size of additional driver-private structure to be allocated 289 * for this ethernet device 290 * 291 * Fill in the fields of the device structure with ethernet-generic 292 * values. Basically does everything except registering the device. 293 * 294 * Constructs a new net device, complete with a private data area of 295 * size @sizeof_priv. A 32-byte (not bit) alignment is enforced for 296 * this private data area. 297 */ 298 299 struct net_device *alloc_etherdev(int sizeof_priv) 300 { 301 return alloc_netdev(sizeof_priv, "eth%d", ether_setup); 302 } 303 EXPORT_SYMBOL(alloc_etherdev); 304