Videos :: Linux Kernel Network Programming

/* pkt_drop.c * Author: Kiran Kankipati * Updated: 09-feb-2017 */ #include <linux/kernel.h> #include <linux/types.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/slab.h> #include <linux/netfilter.h> #include <linux/netfilter_ipv4.h> #include <linux/skbuff.h> #include <linux/udp.h> #include <linux/ip.h> #include <linux/in.h> #include <linux/string.h> #include <linux/init.h> #include <linux/net.h> #include <linux/netdevice.h> #include <linux/socket.h> #include <linux/sockios.h> #include <linux/inet.h> #include <linux/inetdevice.h> #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/if_arp.h> #include <linux/icmp.h> #include <linux/netlink.h> #include <linux/mroute.h> #include <net/checksum.h> #include <net/inet_ecn.h> #include <net/xfrm.h> #include <net/route.h> #include <net/sock.h> #include <net/ip.h> #include <net/tcp.h> #include <net/arp.h> #include <net/udp.h> #include <net/icmp.h> #include <net/inetpeer.h> #include <net/protocol.h> #include <net/flow.h> #include <asm/types.h> static struct nf_hook_ops nfho_pre_routing; unsigned int pre_routing_hook_func(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { //kfree_skb(skb); //- dont do this, this will crash your system. return NF_DROP; //this will drop the packet //return NF_ACCEPT; //this will accept the packet } static int hello_init(void) { //Packet RX nfho_pre_routing.hook = pre_routing_hook_func; nfho_pre_routing.hooknum = NF_INET_PRE_ROUTING; nfho_pre_routing.pf = PF_INET; nfho_pre_routing.priority = NF_IP_PRI_FIRST; nf_register_hook(&nfho_pre_routing); return 0; } static void hello_exit(void) { nf_unregister_hook(&nfho_pre_routing); } module_init(hello_init); module_exit(hello_exit);