学步园

#ifndef IPHEADER_H<br /> #define IPHEADER_H<br /> // 定义TCP头结构<br /> struct TcpHeader<br /> {<br /> unsigned short int th_sport; // 16位源端口<br /> unsigned short int th_dport; // 16位目的端口<br /> unsigned int th_seq; // 32位序列号<br /> unsigned int th_ack; // 32位确认号<br /> unsigned char th_lenres; // 4位首部长度/6位保留字<br /> unsigned char th_flag; // 6位标志位<br /> unsigned short int th_win; // 16位窗口大小<br /> unsigned short int th_sum; // 16位校验和<br /> unsigned short int th_urp; // 16位紧急数据偏移量<br /> };<br /> struct PseudoHeader // 定义伪首部<br /> {<br /> unsigned long saddr; // 源地址<br /> unsigned long daddr; // 目的地址<br /> char mbz; // 固定为0<br /> char ptcl; // 协议类型<br /> unsigned short tcpl; // TCP或者UDP包的长度<br /> };<br /> // 定义IP头结构<br /> struct IpHeader<br /> {<br /> unsigned char ip_hl : 4, ip_v : 4; // 4位首部长度 + 4位IP版本号<br /> unsigned char ip_tos; // 8位服务类型<br /> unsigned short int ip_len; // 16位总长度(字节)<br /> unsigned short int ip_id; // 16位标识<br /> unsigned short int ip_off; // 3位标志位<br /> unsigned char ip_ttl; // 8位生存时间TTL<br /> unsigned char ip_p; // 8位协议(TCP, UDP, ...)<br /> unsigned short int ip_sum; // 16位IP首部校验和<br /> unsigned int ip_src; // 32位源IP地址<br /> unsigned int ip_dst; // 32位目的IP地址<br /> };<br /> // 定义UDP头结构<br /> struct UdpHeader<br /> {<br /> unsigned short uh_sport;<br /> unsigned short uh_dport;<br /> unsigned short uh_len;<br /> unsigned short uh_cksum;<br /> };<br /> // 定义ICMP echo request包的结构<br /> struct IcmpHeader<br /> {<br /> byte type;<br /> byte code;<br /> unsigned short checksum;<br /> unsigned short id;<br /> unsigned short seq;<br /> unsigned long timestamp;<br /> };<br /> #endif // IPHEADER_H<br />

#include <iostream><br /> #include <cstdlib><br /> #include <cstdio><br /> #include <winsock2.h><br /> #include <ws2tcpip.h> // 注意头文件包含的顺序<br /> #include <winbase.h><br /> #include <windows.h><br /> #include <windef.h><br /> #include "ipheader.h"<br /> using namespace std;<br /> #define ICMP_ECHO_REPLY 0<br /> #define ICMP_DEST_UNREACH 3<br /> #define ICMP_TTL_EXPIRE 11<br /> #define ICMP_ECHO_REQUEST 8<br /> #define ICMP_MIN 8 // 最小的ICMP包大小<br /> // 功能：计算校验和<br /> unsigned short ip_checksum(unsigned short *buffer, int size)<br /> {<br /> unsigned long cksum = 0;<br /> // 将所有16位无符号数相加<br /> while (size > 1) {<br /> cksum += *buffer++;<br /> size -= sizeof(unsigned short);<br /> }<br /> if (size) // 加上最后一个BYTE<br /> cksum += *(unsigned char *)buffer;<br /> // 和的前16位和后16位相加<br /> cksum = (cksum >> 16) + (cksum & 0xffff);<br /> cksum += (cksum >> 16);<br /> return (unsigned short)(~cksum);<br /> }<br /> // 初始化icmp数据包的各个字段<br /> // 给data部分填充数据, 计算校验和<br /> void init_ping_packet(IcmpHeader *icmp_hdr, int packet_size, int seq_no)<br /> {<br /> // 设置ICMP报头字段<br /> icmp_hdr->type = 8; // 常量ICMP_ECHO_REQUEST ＝ 8<br /> icmp_hdr->code = 0;<br /> icmp_hdr->checksum = 0;<br /> icmp_hdr->id = (unsigned short)GetCurrentProcessId();<br /> // id号随机，这里以进程号作为id号<br /> icmp_hdr->seq = seq_no;<br /> icmp_hdr->timestamp = GetTickCount();<br /> // 填充data域<br /> const unsigned long int deadmeat = 0xDEADBEEF; // 用于填充的数据部分<br /> char *datapart = (char *)icmp_hdr + sizeof(IcmpHeader); // 指向数据部分<br /> int bytes_left = packet_size - sizeof(IcmpHeader); // 包大小减去首部长度就是数据部分长度<br /> while (bytes_left > 0) {<br /> memcpy(datapart, &deadmeat, min(int(sizeof(deadmeat)), bytes_left));<br /> bytes_left -= sizeof(deadmeat);<br /> datapart += sizeof(deadmeat);<br /> }<br /> // 计算校验和<br /> icmp_hdr->checksum = ip_checksum((unsigned short *)icmp_hdr, packet_size);<br /> }<br /> // 功能：初始化RAW Socket, 初始化目标地址<br /> // 返回值：< 0 失败<br /> int setup_for_ping(const char *host, SOCKET &sd, sockaddr_in &dest)<br /> {<br /> WORD wVersionRequested;<br /> WSADATA wsaData;<br /> int err;<br /> wVersionRequested = MAKEWORD(2, 2);<br /> err = WSAStartup(wVersionRequested, &wsaData); // 初始化<br /> if ( err != 0 ) {<br /> cerr << "WSAStartup Error" << endl;<br /> return -1;<br /> }<br /> // 检查winsock DLL的版本<br /> if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2 ) {<br /> cerr << "wsaData.wVersion != 2 || wsaData.wVersion != 2" << endl;<br /> WSACleanup();<br /> return -1;<br /> }<br /> // 创建原始套接字，协议类型为IPPROTO_ICMP<br /> sd = WSASocket(AF_INET, SOCK_RAW, IPPROTO_ICMP, 0, 0, 0);<br /> if (sd == INVALID_SOCKET) {<br /> cerr << "Failed to create raw socket: " << WSAGetLastError() << endl;<br /> return -1;<br /> }<br /> unsigned int timeout = 1000;<br /> if (setsockopt(sd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout)) == SOCKET_ERROR) {<br /> cerr << "SO_RCVTIMEo setsockopt failed: " << WSAGetLastError() << endl;<br /> return -1;<br /> }<br /> if (setsockopt(sd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout)) == SOCKET_ERROR) {<br /> cerr << "SO_SNDTIMEo setsockopt failed: " << WSAGetLastError() << endl;<br /> return -1;<br /> }<br /> // 初始化目标主机的信息<br /> memset(&dest, 0, sizeof(dest));<br /> // 将命令行的第1个参数转换为目标IP地址<br /> dest.sin_addr.S_un.S_addr = inet_addr(host);<br /> if (dest.sin_addr.S_un.S_addr != INADDR_NONE) {<br /> dest.sin_family = AF_INET;<br /> } else {<br /> cerr << "dest ip not right!";<br /> return -1;<br /> }<br /> return 0;<br /> }<br /> // 功能：发送生成的ICMP包<br /> // 返回值：< 0 发送失败<br /> int send_ping(SOCKET sd, const sockaddr_in &dest, IcmpHeader *send_buf, int packet_size)<br /> {<br /> // 发送send_buf缓冲区中的报文<br /> cout << "Sending " << packet_size << " bytes to " << inet_ntoa(dest.sin_addr) << "..." << flush;<br /> int bwrote = sendto(sd, (char *)send_buf, packet_size, 0, (sockaddr *)&dest, sizeof(dest));<br /> if (bwrote == SOCKET_ERROR) {<br /> cerr << "send failed: " << WSAGetLastError() << endl;<br /> return -1;<br /> } else if (bwrote < packet_size) {<br /> cout << "sent " << bwrote << " bytes..." << flush;<br /> }<br /> return 0;<br /> }<br /> // 发送Ping报文后，接收回复ICMP报文：<br /> // 返回值： < 0 接收失败<br /> int recv_ping(SOCKET sd, sockaddr_in &source, IpHeader *recv_buf, int &packet_size)<br /> {<br /> // 等待Ping回复<br /> int fromlen = sizeof(source);<br /> int bread = recvfrom(sd, (char *)recv_buf, 200, 0, (sockaddr *)&source, &fromlen);<br /> if (bread == SOCKET_ERROR) {<br /> cerr << "read failed: ";<br /> if (WSAGetLastError() == WSAEMSGSIZE)<br /> cerr << "buffer too small" << endl;<br /> else<br /> cerr << "error #" << WSAGetLastError() << endl;<br /> return -1;<br /> }<br /> packet_size = bread;<br /> return 0;<br /> }<br /> // 对接收到的报文进行解析：<br /> // 功能：解析接收到的ICMP报文<br /> // 返回值：-2: 忽略, -1: 失败, 0: 成功<br /> int decode_reply(IpHeader *reply, int bytes, sockaddr_in *from)<br /> {<br /> // 将指针偏移到ICMP报头<br /> unsigned short header_len = reply->ip_hl * 4; // ip包首部长度<br /> IcmpHeader *icmphdr = (IcmpHeader *)((char *)reply + header_len);<br /> // 报文太短<br /> if (bytes < header_len + ICMP_MIN) {<br /> cerr << "too few bytes from " << inet_ntoa(from->sin_addr) << endl;<br /> return -1;<br /> } else if (icmphdr->type != ICMP_ECHO_REPLY) { // 解析回复报文类型<br /> //非正常回复<br /> if (icmphdr->type != ICMP_TTL_EXPIRE) { // ttl减为零<br /> if (icmphdr->type == ICMP_DEST_UNREACH) //主机不可达<br /> cerr << "Destination unreachable" << endl;<br /> else //非法的ICMP包类型<br /> cerr << "Unknown ICMP packet type " << int(icmphdr->type) << " received" << endl;<br /> return -1;<br /> }<br /> } else if (icmphdr->id != (unsigned short)GetCurrentProcessId()) { // id号不匹配<br /> //不是本进程发的包, 可能是同机的其它ping进程发的<br /> return -2;<br /> }<br /> // 输出信息<br /> cout << endl << bytes << " bytes from " << inet_ntoa(from->sin_addr) << ", icmp_seq " << icmphdr->seq << ", ";<br /> if (icmphdr->type == ICMP_TTL_EXPIRE) {<br /> cerr << "TTL expired." << endl;<br /> } else {<br /> cout << "TTL:" << (int)reply->ip_ttl << " ";<br /> cout << "time: " << (GetTickCount() - icmphdr->timestamp) << " ms." << endl;<br /> }<br /> return 0;<br /> }<br /> int main()<br /> {<br /> int i = 0;<br /> SOCKET s;<br /> sockaddr_in dest;<br /> // IcmpHeader icmp_hdr; // sizeof(IcmpHeader = 12)<br /> char sendbuf[200]; // sendbuf包括ICMP头，还有留出写数据的部分<br /> char recv_buf[200]; // sendbuf要接收IP头以及ICMP包，所以要留出足够的空间<br /> int recvlen = 20;<br /> // IpHeader recv_buf;<br /> while (i < 4) {<br /> if (setup_for_ping("127.0.0.1", s, dest)) {<br /> cerr <<"destip not in proper form, exit";<br /> return -1;<br /> }<br /> init_ping_packet((IcmpHeader *)sendbuf, 20, 1000);<br /> // ICMP头长度以及数据加起来为20<br /> send_ping(s, dest, (IcmpHeader *)sendbuf, 20);<br /> recv_ping(s, dest, (IpHeader *)recv_buf, recvlen);<br /> decode_reply((IpHeader *)recv_buf, recvlen, &dest);<br /> i++;<br /> }<br /> getchar();<br /> }<br />