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 <net/dst.h> 57 #include <net/arp.h> 58 #include <net/sock.h> 59 #include <net/ipv6.h> 60 #include <net/ip.h> 61 #include <asm/uaccess.h> 62 #include <asm/system.h> 63 #include <asm/checksum.h> 64 65 extern int __init netdev_boot_setup(char *str); 66 67 __setup("ether=", netdev_boot_setup); 68 69 /* 70 * Create the Ethernet MAC header for an arbitrary protocol layer 71 * 72 * saddr=NULL means use device source address 73 * daddr=NULL means leave destination address (eg unresolved arp) 74 */ 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 81 /* 82 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length 83 * in here instead. It is up to the 802.2 layer to carry protocol information. 84 */ 85 86 if(type!=ETH_P_802_3) 87 eth->h_proto = htons(type); 88 else 89 eth->h_proto = htons(len); 90 91 /* 92 * Set the source hardware address. 93 */ 94 95 if(!saddr) 96 saddr = dev->dev_addr; 97 memcpy(eth->h_source,saddr,dev->addr_len); 98 99 /* 100 * Anyway, the loopback-device should never use this function... 101 */ 102 103 if (dev->flags & (IFF_LOOPBACK|IFF_NOARP)) 104 { 105 memset(eth->h_dest, 0, dev->addr_len); 106 return ETH_HLEN; 107 } 108 109 if(daddr) 110 { 111 memcpy(eth->h_dest,daddr,dev->addr_len); 112 return ETH_HLEN; 113 } 114 115 return -ETH_HLEN; 116 } 117 118 119 /* 120 * Rebuild the Ethernet MAC header. This is called after an ARP 121 * (or in future other address resolution) has completed on this 122 * sk_buff. We now let ARP fill in the other fields. 123 * 124 * This routine CANNOT use cached dst->neigh! 125 * Really, it is used only when dst->neigh is wrong. 126 */ 127 128 int eth_rebuild_header(struct sk_buff *skb) 129 { 130 struct ethhdr *eth = (struct ethhdr *)skb->data; 131 struct net_device *dev = skb->dev; 132 133 switch (eth->h_proto) 134 { 135 #ifdef CONFIG_INET 136 case __constant_htons(ETH_P_IP): 137 return arp_find(eth->h_dest, skb); 138 #endif 139 default: 140 printk(KERN_DEBUG 141 "%s: unable to resolve type %X addresses.\n", 142 dev->name, (int)eth->h_proto); 143 144 memcpy(eth->h_source, dev->dev_addr, dev->addr_len); 145 break; 146 } 147 148 return 0; 149 } 150 151 152 /* 153 * Determine the packet's protocol ID. 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 */ 157 158 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev) 159 { 160 struct ethhdr *eth; 161 unsigned char *rawp; 162 163 skb->mac.raw=skb->data; 164 skb_pull(skb,ETH_HLEN); 165 eth = eth_hdr(skb); 166 skb->input_dev = dev; 167 168 if(*eth->h_dest&1) 169 { 170 if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0) 171 skb->pkt_type=PACKET_BROADCAST; 172 else 173 skb->pkt_type=PACKET_MULTICAST; 174 } 175 176 /* 177 * This ALLMULTI check should be redundant by 1.4 178 * so don't forget to remove it. 179 * 180 * Seems, you forgot to remove it. All silly devices 181 * seems to set IFF_PROMISC. 182 */ 183 184 else if(1 /*dev->flags&IFF_PROMISC*/) 185 { 186 if(memcmp(eth->h_dest,dev->dev_addr, ETH_ALEN)) 187 skb->pkt_type=PACKET_OTHERHOST; 188 } 189 190 if (ntohs(eth->h_proto) >= 1536) 191 return eth->h_proto; 192 193 rawp = skb->data; 194 195 /* 196 * This is a magic hack to spot IPX packets. Older Novell breaks 197 * the protocol design and runs IPX over 802.3 without an 802.2 LLC 198 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This 199 * won't work for fault tolerant netware but does for the rest. 200 */ 201 if (*(unsigned short *)rawp == 0xFFFF) 202 return htons(ETH_P_802_3); 203 204 /* 205 * Real 802.2 LLC 206 */ 207 return htons(ETH_P_802_2); 208 } 209 210 static int eth_header_parse(struct sk_buff *skb, unsigned char *haddr) 211 { 212 struct ethhdr *eth = eth_hdr(skb); 213 memcpy(haddr, eth->h_source, ETH_ALEN); 214 return ETH_ALEN; 215 } 216 217 int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh) 218 { 219 unsigned short type = hh->hh_type; 220 struct ethhdr *eth; 221 struct net_device *dev = neigh->dev; 222 223 eth = (struct ethhdr*) 224 (((u8*)hh->hh_data) + (HH_DATA_OFF(sizeof(*eth)))); 225 226 if (type == __constant_htons(ETH_P_802_3)) 227 return -1; 228 229 eth->h_proto = type; 230 memcpy(eth->h_source, dev->dev_addr, dev->addr_len); 231 memcpy(eth->h_dest, neigh->ha, dev->addr_len); 232 hh->hh_len = ETH_HLEN; 233 return 0; 234 } 235 236 /* 237 * Called by Address Resolution module to notify changes in address. 238 */ 239 240 void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr) 241 { 242 memcpy(((u8*)hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)), 243 haddr, dev->addr_len); 244 } 245 246 EXPORT_SYMBOL(eth_type_trans); 247 248 static int eth_mac_addr(struct net_device *dev, void *p) 249 { 250 struct sockaddr *addr=p; 251 if (netif_running(dev)) 252 return -EBUSY; 253 memcpy(dev->dev_addr, addr->sa_data,dev->addr_len); 254 return 0; 255 } 256 257 static int eth_change_mtu(struct net_device *dev, int new_mtu) 258 { 259 if ((new_mtu < 68) || (new_mtu > 1500)) 260 return -EINVAL; 261 dev->mtu = new_mtu; 262 return 0; 263 } 264 265 /* 266 * Fill in the fields of the device structure with ethernet-generic values. 267 */ 268 void ether_setup(struct net_device *dev) 269 { 270 dev->change_mtu = eth_change_mtu; 271 dev->hard_header = eth_header; 272 dev->rebuild_header = eth_rebuild_header; 273 dev->set_mac_address = eth_mac_addr; 274 dev->hard_header_cache = eth_header_cache; 275 dev->header_cache_update= eth_header_cache_update; 276 dev->hard_header_parse = eth_header_parse; 277 278 dev->type = ARPHRD_ETHER; 279 dev->hard_header_len = ETH_HLEN; 280 dev->mtu = 1500; /* eth_mtu */ 281 dev->addr_len = ETH_ALEN; 282 dev->tx_queue_len = 1000; /* Ethernet wants good queues */ 283 dev->flags = IFF_BROADCAST|IFF_MULTICAST; 284 285 memset(dev->broadcast,0xFF, ETH_ALEN); 286 287 } 288 EXPORT_SYMBOL(ether_setup); 289 290 /** 291 * alloc_etherdev - Allocates and sets up an ethernet device 292 * @sizeof_priv: Size of additional driver-private structure to be allocated 293 * for this ethernet device 294 * 295 * Fill in the fields of the device structure with ethernet-generic 296 * values. Basically does everything except registering the device. 297 * 298 * Constructs a new net device, complete with a private data area of 299 * size @sizeof_priv. A 32-byte (not bit) alignment is enforced for 300 * this private data area. 301 */ 302 303 struct net_device *alloc_etherdev(int sizeof_priv) 304 { 305 return alloc_netdev(sizeof_priv, "eth%d", ether_setup); 306 } 307 EXPORT_SYMBOL(alloc_etherdev); 308