Hello Lukas,
As you said i use following printk with for loop and
included at hook_func1.
for (i=0;i<5;i++)
printk(KERN_DEBUG"Packet data is %02x\t",sb->data[i]);
But i am not getting any output in /var/log/messages. Where am i
wrong? I specified to print only 5 chars at start to check whether i
can get packet dump or not?
What else should i include in module code i posted already
with above lines?
regards,
linux.lover
On Wed, 22 Dec 2004 08:20:42 +0530, linux lover
<linux.lover2004@xxxxxxxxx> wrote:
> Hi all,
> I want to print skb->data contents in kernel module using netfilter module at
> NF_HOOK NF_IP_LOCAL_OUT. How can i do that? I know how to write netfilter
> module like this one
> #define MODULE
> #define __KERNEL__
>
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/skbuff.h>
> #include <linux/ip.h>
> #include <linux/netfilter.h>
> #include <linux/netfilter_ipv4.h>
>
> static struct nf_hook_ops nfho1;
> static unsigned char *packet_ip = "\x7f\x00\x00\x0b";
>
> unsigned int hook_func1(unsigned int hooknum,struct sk_buff **skb,
> const struct net_device *in,
> const struct net_device *out,
> int (*okfn)(struct sk_buff *))
> {
> struct sk_buff *sb = *skb;
> printk(KERN_DEBUG "calling hook_func at NF_IP_LOCAL_OUT\n");
> if (sb->nh.iph->saddr == *(unsigned int *)packet_ip)
> {
> /*CODE REQUIRE TO BE INCLUDED HERE*/
> return NF_ACCEPT;
> }
> else
> return NF_ACCEPT;
>
> }
>
> static int __init init(void)
> {
> nfho1.hook = hook_func1;
> nfho1.hooknum = NF_IP_LOCAL_OUT;
> nfho1.pf = PF_INET;
> nfho1.priority = NF_IP_PRI_FIRST;
> nf_register_hook(&nfho1);
> return 0;
> }
>
> static void __exit fini(void)
> {
> nf_unregister_hook(&nfho1);
> }
> module_init(init);
> module_exit(fini);
> MODULE_LICENSE("GPL");
>
> But how can i print those HEX codes in packet?
> regards,
> linux.lover
>
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