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.
6 * Ethernet-type device handling.
8 * Version: @(#)eth.c 1.0.7 05/25/93
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
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>
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
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.
34 * This program is free software; you can redistribute it and/or
35 * modify it under the terms of the GNU General Public License
36 * as published by the Free Software Foundation; either version
37 * 2 of the License, or (at your option) any later version.
39 #include <linux/types.h>
40 #include <linux/kernel.h>
41 #include <linux/sched.h>
42 #include <linux/string.h>
44 #include <linux/socket.h>
46 #include <linux/inet.h>
48 #include <linux/netdevice.h>
49 #include <linux/etherdevice.h>
50 #include <linux/skbuff.h>
51 #include <linux/errno.h>
52 #include <linux/config.h>
53 #include <linux/init.h>
59 #include <asm/uaccess.h>
60 #include <asm/system.h>
61 #include <asm/checksum.h>
63 static int __init eth_setup(char *str)
68 str = get_options(str, ARRAY_SIZE(ints), ints);
73 memset(&map, -1, sizeof(map));
77 map.base_addr = ints[2];
79 map.mem_start = ints[3];
81 map.mem_end = ints[4];
83 /* Add new entry to the list */
84 return netdev_boot_setup_add(str, &map);
87 __setup("ether=", eth_setup);
90 * Create the Ethernet MAC header for an arbitrary protocol layer
92 * saddr=NULL means use device source address
93 * daddr=NULL means leave destination address (eg unresolved arp)
96 int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
97 void *daddr, void *saddr, unsigned len)
99 struct ethhdr *eth = (struct ethhdr *)skb_push(skb,ETH_HLEN);
102 * Set the protocol type. For a packet of type ETH_P_802_3 we put the length
103 * in here instead. It is up to the 802.2 layer to carry protocol information.
106 if(type!=ETH_P_802_3)
107 eth->h_proto = htons(type);
109 eth->h_proto = htons(len);
112 * Set the source hardware address.
116 memcpy(eth->h_source,saddr,dev->addr_len);
118 memcpy(eth->h_source,dev->dev_addr,dev->addr_len);
121 * Anyway, the loopback-device should never use this function...
124 if (dev->flags & (IFF_LOOPBACK|IFF_NOARP))
126 memset(eth->h_dest, 0, dev->addr_len);
127 return(dev->hard_header_len);
132 memcpy(eth->h_dest,daddr,dev->addr_len);
133 return dev->hard_header_len;
136 return -dev->hard_header_len;
141 * Rebuild the Ethernet MAC header. This is called after an ARP
142 * (or in future other address resolution) has completed on this
143 * sk_buff. We now let ARP fill in the other fields.
145 * This routine CANNOT use cached dst->neigh!
146 * Really, it is used only when dst->neigh is wrong.
149 int eth_rebuild_header(struct sk_buff *skb)
151 struct ethhdr *eth = (struct ethhdr *)skb->data;
152 struct net_device *dev = skb->dev;
154 switch (eth->h_proto)
157 case __constant_htons(ETH_P_IP):
158 return arp_find(eth->h_dest, skb);
162 "%s: unable to resolve type %X addresses.\n",
163 dev->name, (int)eth->h_proto);
165 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
174 * Determine the packet's protocol ID. The rule here is that we
175 * assume 802.3 if the type field is short enough to be a length.
176 * This is normal practice and works for any 'now in use' protocol.
179 unsigned short eth_type_trans(struct sk_buff *skb, struct net_device *dev)
184 skb->mac.raw=skb->data;
185 skb_pull(skb,dev->hard_header_len);
186 eth= skb->mac.ethernet;
190 if(memcmp(eth->h_dest,dev->broadcast, ETH_ALEN)==0)
191 skb->pkt_type=PACKET_BROADCAST;
193 skb->pkt_type=PACKET_MULTICAST;
197 * This ALLMULTI check should be redundant by 1.4
198 * so don't forget to remove it.
200 * Seems, you forgot to remove it. All silly devices
201 * seems to set IFF_PROMISC.
204 else if(1 /*dev->flags&IFF_PROMISC*/)
206 if(memcmp(eth->h_dest,dev->dev_addr, ETH_ALEN))
207 skb->pkt_type=PACKET_OTHERHOST;
210 if (ntohs(eth->h_proto) >= 1536)
216 * This is a magic hack to spot IPX packets. Older Novell breaks
217 * the protocol design and runs IPX over 802.3 without an 802.2 LLC
218 * layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
219 * won't work for fault tolerant netware but does for the rest.
221 if (*(unsigned short *)rawp == 0xFFFF)
222 return htons(ETH_P_802_3);
227 return htons(ETH_P_802_2);
230 int eth_header_parse(struct sk_buff *skb, unsigned char *haddr)
232 struct ethhdr *eth = skb->mac.ethernet;
233 memcpy(haddr, eth->h_source, ETH_ALEN);
237 int eth_header_cache(struct neighbour *neigh, struct hh_cache *hh)
239 unsigned short type = hh->hh_type;
240 struct ethhdr *eth = (struct ethhdr*)(((u8*)hh->hh_data) + 2);
241 struct net_device *dev = neigh->dev;
243 if (type == __constant_htons(ETH_P_802_3))
247 memcpy(eth->h_source, dev->dev_addr, dev->addr_len);
248 memcpy(eth->h_dest, neigh->ha, dev->addr_len);
249 hh->hh_len = ETH_HLEN;
254 * Called by Address Resolution module to notify changes in address.
257 void eth_header_cache_update(struct hh_cache *hh, struct net_device *dev, unsigned char * haddr)
259 memcpy(((u8*)hh->hh_data) + 2, haddr, dev->addr_len);