下面可以利用Raw Socket发送生成的ICMP报文:
//功能:发送生成的ICMP包 //返回值:<0 发送失败 int send_ping(SOCKET sd, const sockaddr_in &dest, ICMPHeader *send_buf, int packet_size) { // 发送send_buf缓冲区中的报文 cout << "Sending " << packet_size << " bytes to " << inet_ntoa(dest.sin_addr) << "..." << flush; int bwrote = sendto(sd, (char*)send_buf, packet_size, 0, (sockaddr*) &dest,sizeof(dest)); if (bwrote == SOCKET_ERROR) { cerr << "send failed: " << WSAGetLastError() << endl; return - 1; } else if (bwrote < packet_size) { cout << "sent " << bwrote << " bytes..." << flush; } return 0; }
发送Ping报文后,我们需要接收Ping回复ICMP报文:
//功能:接收Ping回复 //返回值: <0 接收失败 int recv_ping(SOCKET sd, sockaddr_in &source, IPHeader *recv_buf, int packet_size) { // 等待Ping回复 int fromlen = sizeof(source); int bread = recvfrom(sd, (char*)recv_buf, packet_size + sizeof(IPHeader), 0,(sockaddr*) &source, &fromlen); if (bread == SOCKET_ERROR) { cerr << "read failed: "; if (WSAGetLastError() == WSAEMSGSIZE) { cerr << "buffer too small" << endl; } else { cerr << "error #" << WSAGetLastError() << endl; } return - 1; } return 0; }
并使用如下函数对接收到的报文进行解析:
// 功能:解析接收到的ICMP报文 // 返回值: -2忽略, -1失败, 0 成功 int decode_reply(IPHeader *reply, int bytes, sockaddr_in *from) { // 偏移到ICMP报头 unsigned short header_len = reply->h_len *4; ICMPHeader *icmphdr = (ICMPHeader*)((char*)reply + header_len);
// 报文太短 if (bytes < header_len + ICMP_MIN) { cerr << "too few bytes from " << inet_ntoa(from->sin_addr) << endl; return - 1; } // 解析回复报文类型 else if (icmphdr->type != ICMP_ECHO_REPLY) {
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