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
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.
33 * Andrew Morton : 26Feb01: kill ether_setup() - use netdev_boot_setup().
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.
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>
46 #include <linux/socket.h>
48 #include <linux/inet.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>
61 #include <asm/uaccess.h>
62 #include <asm/system.h>
63 #include <asm/checksum.h>
65 extern int __init
netdev_boot_setup(char *str
);
67 __setup("ether=", netdev_boot_setup
);
70 * Create the Ethernet MAC header for an arbitrary protocol layer
72 * saddr=NULL means use device source address
73 * daddr=NULL means leave destination address (eg unresolved arp)
76 int eth_header(struct sk_buff
*skb
, struct net_device
*dev
, unsigned short type
,
77 void *daddr
, void *saddr
, unsigned len
)
79 struct ethhdr
*eth
= (struct ethhdr
*)skb_push(skb
,ETH_HLEN
);
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.
87 eth
->h_proto
= htons(type
);
89 eth
->h_proto
= htons(len
);
92 * Set the source hardware address.
96 saddr
= dev
->dev_addr
;
97 memcpy(eth
->h_source
,saddr
,dev
->addr_len
);
100 * Anyway, the loopback-device should never use this function...
103 if (dev
->flags
& (IFF_LOOPBACK
|IFF_NOARP
))
105 memset(eth
->h_dest
, 0, dev
->addr_len
);
111 memcpy(eth
->h_dest
,daddr
,dev
->addr_len
);
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.
124 * This routine CANNOT use cached dst->neigh!
125 * Really, it is used only when dst->neigh is wrong.
128 int eth_rebuild_header(struct sk_buff
*skb
)
130 struct ethhdr
*eth
= (struct ethhdr
*)skb
->data
;
131 struct net_device
*dev
= skb
->dev
;
133 switch (eth
->h_proto
)
136 case __constant_htons(ETH_P_IP
):
137 return arp_find(eth
->h_dest
, skb
);
141 "%s: unable to resolve type %X addresses.\n",
142 dev
->name
, (int)eth
->h_proto
);
144 memcpy(eth
->h_source
, dev
->dev_addr
, dev
->addr_len
);
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.
158 __be16
eth_type_trans(struct sk_buff
*skb
, struct net_device
*dev
)
163 skb
->mac
.raw
=skb
->data
;
164 skb_pull(skb
,ETH_HLEN
);
166 skb
->input_dev
= dev
;
170 if(memcmp(eth
->h_dest
,dev
->broadcast
, ETH_ALEN
)==0)
171 skb
->pkt_type
=PACKET_BROADCAST
;
173 skb
->pkt_type
=PACKET_MULTICAST
;
177 * This ALLMULTI check should be redundant by 1.4
178 * so don't forget to remove it.
180 * Seems, you forgot to remove it. All silly devices
181 * seems to set IFF_PROMISC.
184 else if(1 /*dev->flags&IFF_PROMISC*/)
186 if(memcmp(eth
->h_dest
,dev
->dev_addr
, ETH_ALEN
))
187 skb
->pkt_type
=PACKET_OTHERHOST
;
190 if (ntohs(eth
->h_proto
) >= 1536)
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.
201 if (*(unsigned short *)rawp
== 0xFFFF)
202 return htons(ETH_P_802_3
);
207 return htons(ETH_P_802_2
);
210 static int eth_header_parse(struct sk_buff
*skb
, unsigned char *haddr
)
212 struct ethhdr
*eth
= eth_hdr(skb
);
213 memcpy(haddr
, eth
->h_source
, ETH_ALEN
);
217 int eth_header_cache(struct neighbour
*neigh
, struct hh_cache
*hh
)
219 unsigned short type
= hh
->hh_type
;
221 struct net_device
*dev
= neigh
->dev
;
223 eth
= (struct ethhdr
*)
224 (((u8
*)hh
->hh_data
) + (HH_DATA_OFF(sizeof(*eth
))));
226 if (type
== __constant_htons(ETH_P_802_3
))
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
;
237 * Called by Address Resolution module to notify changes in address.
240 void eth_header_cache_update(struct hh_cache
*hh
, struct net_device
*dev
, unsigned char * haddr
)
242 memcpy(((u8
*)hh
->hh_data
) + HH_DATA_OFF(sizeof(struct ethhdr
)),
243 haddr
, dev
->addr_len
);
246 EXPORT_SYMBOL(eth_type_trans
);
248 static int eth_mac_addr(struct net_device
*dev
, void *p
)
250 struct sockaddr
*addr
=p
;
251 if (netif_running(dev
))
253 memcpy(dev
->dev_addr
, addr
->sa_data
,dev
->addr_len
);
257 static int eth_change_mtu(struct net_device
*dev
, int new_mtu
)
259 if ((new_mtu
< 68) || (new_mtu
> 1500))
266 * Fill in the fields of the device structure with ethernet-generic values.
268 void ether_setup(struct net_device
*dev
)
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
;
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
;
285 memset(dev
->broadcast
,0xFF, ETH_ALEN
);
288 EXPORT_SYMBOL(ether_setup
);
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
295 * Fill in the fields of the device structure with ethernet-generic
296 * values. Basically does everything except registering the device.
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.
303 struct net_device
*alloc_etherdev(int sizeof_priv
)
305 return alloc_netdev(sizeof_priv
, "eth%d", ether_setup
);
307 EXPORT_SYMBOL(alloc_etherdev
);