分类： LINUX
2008-11-04 16:00:24
一．怎么样广播数据
根据AODV中recv（）函数的代码,我们可以知道，只需要将IP包头的目的地址设为广播地址即可，ih->daddr() != IP_BROADCAST
void
AODV::recv(Packet *p, Handler*) {
//访问通用以及IP包头
struct hdr_cmn *ch = HDR_CMN(p);
struct hdr_ip *ih = HDR_IP(p);
assert(initialized());
//assert(p->incoming == 0);
// XXXXX NOTE: use of incoming flag has been depracated; In order to track direction of pkt flow, direction_ in hdr_cmn is used instead. see packet.h for details.
if(ch->ptype() == PT_AODV) {
ih->ttl_ -= 1;
recvAODV(p);
return;
}
/*
* Must be a packet I'm originating...
*/
if((ih->saddr() == index) && (ch->num_forwards() == 0)) {
/*
* Add the IP Header
*/
ch->size() += IP_HDR_LEN;
// Added by Parag Dadhania && John Novatnack to handle broadcasting
if ( (u_int32_t)ih->daddr() != IP_BROADCAST)
ih->ttl_ = NETWORK_DIAMETER;
}
/*
* I received a packet that I sent. Probably
* a routing loop.
*/
else if(ih->saddr() == index) {
drop(p, DROP_RTR_ROUTE_LOOP);
return;
}
/*
* Packet I'm forwarding...
*/
else {
/*
* Check the TTL. If it is zero, then discard.
*/
if(--ih->ttl_ == 0) {
drop(p, DROP_RTR_TTL);
return;
}
}
// Added by Parag Dadhania && John Novatnack to handle broadcasting
if ( (u_int32_t)ih->daddr() != IP_BROADCAST)
rt_resolve(p);
else
forward((aodv_rt_entry*) 0, p, NO_DELAY);
}
