1 /*
2  *  ebt_redirect
3  *
4  *	Authors:
5  *	Bart De Schuymer <bdschuym@pandora.be>
6  *
7  *  April, 2002
8  *
9  */
10 
11 #include <linux/netfilter_bridge/ebtables.h>
12 #include <linux/netfilter_bridge/ebt_redirect.h>
13 #include <linux/module.h>
14 #include <net/sock.h>
15 #include "../br_private.h"
16 
17 static int ebt_target_redirect(struct sk_buff **pskb, unsigned int hooknr,
18    const struct net_device *in, const struct net_device *out,
19    const void *data, unsigned int datalen)
20 {
21 	struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
22 
23 	if (skb_shared(*pskb) || skb_cloned(*pskb)) {
24 		struct sk_buff *nskb;
25 
26 		nskb = skb_copy(*pskb, GFP_ATOMIC);
27 		if (!nskb)
28 			return NF_DROP;
29 		if ((*pskb)->sk)
30 			skb_set_owner_w(nskb, (*pskb)->sk);
31 		kfree_skb(*pskb);
32 		*pskb = nskb;
33 	}
34 	if (hooknr != NF_BR_BROUTING)
35 		memcpy(eth_hdr(*pskb)->h_dest,
36 		       in->br_port->br->dev->dev_addr, ETH_ALEN);
37 	else
38 		memcpy(eth_hdr(*pskb)->h_dest, in->dev_addr, ETH_ALEN);
39 	(*pskb)->pkt_type = PACKET_HOST;
40 	return info->target;
41 }
42 
43 static int ebt_target_redirect_check(const char *tablename, unsigned int hookmask,
44    const struct ebt_entry *e, void *data, unsigned int datalen)
45 {
46 	struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
47 
48 	if (datalen != EBT_ALIGN(sizeof(struct ebt_redirect_info)))
49 		return -EINVAL;
50 	if (BASE_CHAIN && info->target == EBT_RETURN)
51 		return -EINVAL;
52 	CLEAR_BASE_CHAIN_BIT;
53 	if ( (strcmp(tablename, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING)) &&
54 	     (strcmp(tablename, "broute") || hookmask & ~(1 << NF_BR_BROUTING)) )
55 		return -EINVAL;
56 	if (INVALID_TARGET)
57 		return -EINVAL;
58 	return 0;
59 }
60 
61 static struct ebt_target redirect_target =
62 {
63 	.name		= EBT_REDIRECT_TARGET,
64 	.target		= ebt_target_redirect,
65 	.check		= ebt_target_redirect_check,
66 	.me		= THIS_MODULE,
67 };
68 
69 static int __init init(void)
70 {
71 	return ebt_register_target(&redirect_target);
72 }
73 
74 static void __exit fini(void)
75 {
76 	ebt_unregister_target(&redirect_target);
77 }
78 
79 module_init(init);
80 module_exit(fini);
81 MODULE_LICENSE("GPL");
82