#ifndef ns_pings_h
#define ns_pings_h#include "agent.h"
#include "tclcl.h"
#include "packet.h"
#include "address.h"
#include "ip.h"struct hdr_pings {
?? ?char ret; ? ? ? ? ? ? ? ?//ret，如果包由来自发送方到被ping的节点时将会被设置为‘0’，在返回的路上，它将会被设置为‘1’。
?? ?double send_time; ? ? ?? ?// send_time 是一个时间戳，发送的时候设置，将会被用来计算来回的时间。
/*
??? ?double rcv_time;?? ?// when ping arrived to receiver
??? ?int seq;?? ??? ?// sequence number
?? ?// Header access methods
?? ?static int offset_; // required by PacketHeaderManager
?? ?inline static int& offset() { return offset_; }
?? ?inline static hdr_ping* access(const Packet* p) {
?? ??? ?return (hdr_ping*) p->access(offset_);
?? ?}
*/
};class PingsAgent : public Agent {
public:
?? ?PingsAgent();
??? ?//int seq;?? ?// a send sequence number like in real ping
?? ?//int oneway; ?? ?// enable seq number and one-way delay printouts
?? ?int command(int argc, const char*const* argv);
?? ?void recv(Packet*, Handler*);
protected:
?? ?int off_ping_;
};#endif // ns_pings_h
