![Andrew Morton](/assets/img/avatar_default.png)
Every netfilter module uses `init' for its module_init() function and `fini' or `cleanup' for its module_exit() function. Problem is, this creates uninformative initcall_debug output and makes ctags rather useless. So go through and rename them all to $(filename)_init and $(filename)_fini. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
/* module that allows mangling of the arp payload */
|
|
#include <linux/module.h>
|
|
#include <linux/netfilter_arp/arpt_mangle.h>
|
|
#include <net/sock.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
|
|
MODULE_DESCRIPTION("arptables arp payload mangle target");
|
|
|
|
static unsigned int
|
|
target(struct sk_buff **pskb,
|
|
const struct net_device *in, const struct net_device *out,
|
|
unsigned int hooknum, const struct xt_target *target,
|
|
const void *targinfo, void *userinfo)
|
|
{
|
|
const struct arpt_mangle *mangle = targinfo;
|
|
struct arphdr *arp;
|
|
unsigned char *arpptr;
|
|
int pln, hln;
|
|
|
|
if (skb_shared(*pskb) || skb_cloned(*pskb)) {
|
|
struct sk_buff *nskb;
|
|
|
|
nskb = skb_copy(*pskb, GFP_ATOMIC);
|
|
if (!nskb)
|
|
return NF_DROP;
|
|
if ((*pskb)->sk)
|
|
skb_set_owner_w(nskb, (*pskb)->sk);
|
|
kfree_skb(*pskb);
|
|
*pskb = nskb;
|
|
}
|
|
|
|
arp = (*pskb)->nh.arph;
|
|
arpptr = (*pskb)->nh.raw + sizeof(*arp);
|
|
pln = arp->ar_pln;
|
|
hln = arp->ar_hln;
|
|
/* We assume that pln and hln were checked in the match */
|
|
if (mangle->flags & ARPT_MANGLE_SDEV) {
|
|
if (ARPT_DEV_ADDR_LEN_MAX < hln ||
|
|
(arpptr + hln > (**pskb).tail))
|
|
return NF_DROP;
|
|
memcpy(arpptr, mangle->src_devaddr, hln);
|
|
}
|
|
arpptr += hln;
|
|
if (mangle->flags & ARPT_MANGLE_SIP) {
|
|
if (ARPT_MANGLE_ADDR_LEN_MAX < pln ||
|
|
(arpptr + pln > (**pskb).tail))
|
|
return NF_DROP;
|
|
memcpy(arpptr, &mangle->u_s.src_ip, pln);
|
|
}
|
|
arpptr += pln;
|
|
if (mangle->flags & ARPT_MANGLE_TDEV) {
|
|
if (ARPT_DEV_ADDR_LEN_MAX < hln ||
|
|
(arpptr + hln > (**pskb).tail))
|
|
return NF_DROP;
|
|
memcpy(arpptr, mangle->tgt_devaddr, hln);
|
|
}
|
|
arpptr += hln;
|
|
if (mangle->flags & ARPT_MANGLE_TIP) {
|
|
if (ARPT_MANGLE_ADDR_LEN_MAX < pln ||
|
|
(arpptr + pln > (**pskb).tail))
|
|
return NF_DROP;
|
|
memcpy(arpptr, &mangle->u_t.tgt_ip, pln);
|
|
}
|
|
return mangle->target;
|
|
}
|
|
|
|
static int
|
|
checkentry(const char *tablename, const void *e, const struct xt_target *target,
|
|
void *targinfo, unsigned int targinfosize, unsigned int hook_mask)
|
|
{
|
|
const struct arpt_mangle *mangle = targinfo;
|
|
|
|
if (mangle->flags & ~ARPT_MANGLE_MASK ||
|
|
!(mangle->flags & ARPT_MANGLE_MASK))
|
|
return 0;
|
|
|
|
if (mangle->target != NF_DROP && mangle->target != NF_ACCEPT &&
|
|
mangle->target != ARPT_CONTINUE)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static struct arpt_target arpt_mangle_reg = {
|
|
.name = "mangle",
|
|
.target = target,
|
|
.targetsize = sizeof(struct arpt_mangle),
|
|
.checkentry = checkentry,
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init arpt_mangle_init(void)
|
|
{
|
|
if (arpt_register_target(&arpt_mangle_reg))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit arpt_mangle_fini(void)
|
|
{
|
|
arpt_unregister_target(&arpt_mangle_reg);
|
|
}
|
|
|
|
module_init(arpt_mangle_init);
|
|
module_exit(arpt_mangle_fini);
|