packet_in.c

无线网络路有协议aodv的 linux的实现

/***************************************************************************
                          packet_in.c  -  description
                             -------------------
    begin                : Mon Jul 29 2002
    copyright            : (C) 2002 by Luke Klein-Berndt
    email                : [e-mail]
 ***************************************************************************/

#include "packet_in.h"

int valid_aodv_packet(int numbytes, int type, char *data)
{


    rerr *tmp_rerr;
    rreq *tmp_rreq;
    rrep *tmp_rrep;
    switch (type)
    {
        //RREQ
    case 1:
				tmp_rreq = (rreq *) data;
        //If it is a normal route rreq
				if (numbytes == sizeof(rreq))
						return 1;
 
        break;

        //RREP
    case 2:
				tmp_rrep = (rrep *) data;

				if (numbytes == sizeof(rrep))
						return 1;
				
				break;
        //RERR
    case 3:

        // Normal RERR
        tmp_rerr = (rerr *) data;
        if (numbytes == (sizeof(rerr) + (sizeof(aodv_dst) * tmp_rerr->dst_count)))
        {
            return 1;
        }
        break;

    case 4:                    //Normal RREP-ACK
        if (numbytes == sizeof(rrep_ack))
	        return 1;
        break;

    default:
        break;
    }

    return 0;
}




int packet_in(struct sk_buff *packet)
{
    struct net_device *dev;
    struct iphdr *ip;
    aodv_route *tmp_route;
    aodv_neigh *tmp_neigh;
    u_int32_t tmp_ip;



    // Create aodv message types
    u_int8_t aodv_type;


    //The packets which come in still have their headers from the IP and UDP
    int start_point = sizeof(struct udphdr) + sizeof(struct iphdr);


    //get pointers to the important parts of the message
    ip = packet->nh.iph;
    dev = packet->dev;


 /*   if (strcmp(dev->name, "lo") == 0)
    {
        return NF_DROP;
   }*/
    //For all AODV packets the type is the first byte.
    aodv_type = (int) packet->data[start_point];

    if (!valid_aodv_packet(packet->len - start_point, aodv_type, packet->data + start_point))
    {
        printk(KERN_NOTICE
               "AODV: Packet of type: %d and of size %u from: %s failed packet check!\n", aodv_type, packet->len - start_point, inet_ntoa(ip->saddr));
        return NF_DROP;

    }


	/*	tmp_neigh = find_aodv_neigh_by_hw(&(packet->mac.ethernet->h_source));

		if (tmp_neigh != NULL)
		{
	    delete_timer(tmp_neigh->ip, TASK_NEIGHBOR);
  	  insert_timer(TASK_NEIGHBOR, HELLO_INTERVAL * (1 + ALLOWED_HELLO_LOSS) + 100, tmp_neigh->ip);
    	update_timer_queue();
    }
*/

 
    //place packet in the event queue!
    insert_task(aodv_type, packet);

    return NF_ACCEPT;
}



unsigned int input_handler(unsigned int hooknum, struct sk_buff **skb,
                           const struct net_device *in, const struct net_device *out, int (*okfn) (struct sk_buff *))
{
    struct iphdr *ip = (*skb)->nh.iph;
    struct iphdr *dev_ip = in->ip_ptr;
    void *p = (uint32_t *) ip + ip->ihl;
    struct udphdr *udp = p; //(struct udphdr *) ip + ip->ihl;
    struct ethhdr *mac = (*skb)->mac.ethernet;  //Thanks to Randy Pitz for adding this extra check...
    
    
    if ((*skb)->h.uh != NULL)
    {

        if ((udp->dest == htons(AODVPORT)) && (mac->h_proto == htons(ETH_P_IP)))
        {
        
            if (dev_ip->saddr != ip->saddr)
            {
                return packet_in(*(skb));
            } else
            {
            		printk("dropping packet from: %s\n",inet_ntoa(ip->saddr));
            		return NF_DROP;
            }
        }
    }

    return NF_ACCEPT;

}