How to filter and intercept Linux packets by using net_dev_add() API?
- by Khajavi
I'm writing ethernet network driver for linux. I want to receive packets, edit and resend them.
I know how to edit the packet in packet_interceptor function, but how can I drop incoming packets in this function??
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/sock.h>
struct packet_type my_proto;
int packet_interceptor(struct sk_buff *skb,
struct net_device *dev,
struct packet_type *pt,
struct net_device *orig_dev) {
// I dont want certain packets go to upper in net_devices for further processing.
// How can I drop sk_buff here?!
return 0;
}
static int hello_init( void ) {
printk(KERN_INFO "Hello, world!\n");
my_proto.type = htons(ETH_P_ALL);
my_proto.dev = NULL;
my_proto.func = packet_interceptor;
dev_add_pack(&my_proto);
return 0;
}
static void hello_exit(void) {
dev_remove_pack(&my_proto);
printk(KERN_INFO "Bye, world\n");
}
module_init(hello_init);
module_exit(hello_exit);
