/*               Kernel AODV  v2.0National Institute of Standards and Technology               Luke Klein-Berndt-----------------------------------------------------  Version 2.0 new features:     * Updated to AODV draft version 11     * Managed internet gatewaying     * Monitor wireles signal strength     * Many bug fixes!-----------------------------------------------------Originally based upon MadHoc code. I am notsure how much of it is left anymore, but MadHocproved to be a great starting point.MadHoc was written by - Fredrik Lilieblad,Oskar Mattsson, Petra Nylund, Dan Ouchterlonyand Anders Roxenhag Mail: mad-hoc@flyinglinux.netThis software is Open Source under the GNU General Public Licence.*/#include "packet_out.h"/****************************************************   packet_out----------------------------------------------------All packets going out of the computer getintercepted by netfilter and passed to thisfunction.****************************************************/extern u_int32_t        g_my_ip;extern u_int32_t  g_broadcast_ip;extern struct nf_hook_ops output_filter;/****************************************************   output_handler----------------------------------------------------Looks at all the packets leaving the computer****************************************************/unsigned int output_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;    struct route_table_entry  *tmp_route;    struct net_device *dev;    // get some useful pointers    ip  = (*skb)->nh.iph;    dev = (*skb)->dev;#ifdef TRACE    printk("PACKET_OUT: entered\n");#endif    if (ip->daddr==g_broadcast_ip)    {#ifdef TRACE        printk("PACKET_OUT: Broadcast Packet - exit\n");#endif        return NF_ACCEPT;    }    if (adhoc_subnet_test(ip->daddr))    {        //Try to get a route to the destination        tmp_route=find_route_table_entry(ip->daddr);        //If the there is no route or it is marked for deletion        if ((tmp_route==NULL) || !(tmp_route->route_valid))        {            //if it is a broadcast message            //it is a unknown route time to find a new one#ifdef MESSAGES            printk("PACKET_OUT: Couldn't find a route to: %s, sending out a RREQ!\n",inet_ntoa(ip->daddr));#endif            gen_rreq(g_my_ip,ip->daddr);#ifdef TRACE            printk("PACKET_OUT: Tried to find route exited\n");#endif            return NF_QUEUE;        }        else        {            tmp_route->lifetime = MAX(tmp_route->lifetime,getcurrtime() + ACTIVE_ROUTE_TIMEOUT);        #ifdef TRACE            printk("PACKET_OUT: Have route updated timer -exited \n");        #endif            return NF_ACCEPT;        }    }    else        return NF_ACCEPT;}