C++编写的Tracert程序

/*---------------------------------------------------------- 功能说明：该程序简单实现了Windows操作系统的tracert命令功能， 可以输出IP报文从本机出发到达目的主机所经过的路由信息。 注意：程序编译时应使用1字节对齐方式调整边界! -----------------------------------------------------------*/ #include <iostream.h> #include <iomanip.h> #include <winsock2.h> #include <ws2tcpip.h> #include "itracert.h" //////////////////////////////////////////////////////// int main(int argc, char* argv[]) { //检查命令行参数 if (argc != 2) { cerr << "\nUsage: itracert ip_or_hostname\n"; return -1; } //初始化winsock2环境 WSADATA wsa; if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) { cerr << "\nFailed to initialize the WinSock2 DLL\n" << "error code: " << WSAGetLastError() << endl; return -1; } //将命令行参数转换为IP地址 u_long ulDestIP = inet_addr(argv[1]); if (ulDestIP == INADDR_NONE) { //转换不成功时按域名解析 hostent* pHostent = gethostbyname(argv[1]); if (pHostent) { ulDestIP = (*(in_addr*)pHostent->h_addr).s_addr; //输出屏幕信息 cout << "\nTracing route to " << argv[1] << " [" << inet_ntoa(*(in_addr*)(&ulDestIP)) << "]" << " with a maximum of " << DEF_MAX_HOP << " hops.\n" << endl; } else //解析主机名失败 { cerr << "\nCould not resolve the host name " << argv[1] << '\n' << "error code: " << WSAGetLastError() << endl; WSACleanup(); return -1; } } else { //输出屏幕信息 cout << "\nTracing route to " << argv[1] << " with a maximum of " << DEF_MAX_HOP << " hops.\n" << endl; } //填充目的Socket地址 sockaddr_in destSockAddr; ZeroMemory(&destSockAddr, sizeof(sockaddr_in)); destSockAddr.sin_family = AF_INET; destSockAddr.sin_addr.s_addr = ulDestIP; //使用ICMP协议创建Raw Socket SOCKET sockRaw = WSASocket(AF_INET, SOCK_RAW, IPPROTO_ICMP, NULL, 0, WSA_FLAG_OVERLAPPED); if (sockRaw == INVALID_SOCKET) { cerr << "\nFailed to create a raw socket\n" << "error code: " << WSAGetLastError() << endl; WSACleanup(); return -1; } //设置端口属性 int iTimeout = DEF_ICMP_TIMEOUT; if (setsockopt(sockRaw, SOL_SOCKET, SO_RCVTIMEO, (char*)&iTimeout, sizeof(iTimeout)) == SOCKET_ERROR) { cerr << "\nFailed to set recv timeout\n" << "error code: " << WSAGetLastError() << endl; closesocket(sockRaw); WSACleanup(); return -1; } if (setsockopt(sockRaw, SOL_SOCKET, SO_SNDTIMEO, (char*)&iTimeout, sizeof(iTimeout)) == SOCKET_ERROR) { cerr << "\nFailed to set send timeout\n" << "error code: " << WSAGetLastError() << endl; closesocket(sockRaw); WSACleanup(); return -1; } //创建ICMP包发送缓冲区和接收缓冲区 char IcmpSendBuf[sizeof(ICMP_HEADER)+DEF_ICMP_DATA_SIZE]; memset(IcmpSendBuf, 0, sizeof(IcmpSendBuf)); char IcmpRecvBuf[MAX_ICMP_PACKET_SIZE]; memset(IcmpRecvBuf, 0, sizeof(IcmpRecvBuf)); //填充待发送的ICMP包 ICMP_HEADER* pIcmpHeader = (ICMP_HEADER*)IcmpSendBuf; pIcmpHeader->type = ICMP_ECHO_REQUEST; pIcmpHeader->code = 0; pIcmpHeader->id = (USHORT)GetCurrentProcessId(); memset(IcmpSendBuf+sizeof(ICMP_HEADER), 'E', DEF_ICMP_DATA_SIZE); //开始探测路由 DECODE_RESULT stDecodeResult; BOOL bReachDestHost = FALSE; USHORT usSeqNo = 0; int iTTL = 1; int iMaxHop = DEF_MAX_HOP; while (!bReachDestHost && iMaxHop--) { //设置IP数据报头的ttl字段 setsockopt(sockRaw, IPPROTO_IP, IP_TTL, (char*)&iTTL, sizeof(iTTL)); //输出当前跳站数作为路由信息序号 cout << setw(3) << iTTL << flush; //填充ICMP数据报剩余字段 ((ICMP_HEADER*)IcmpSendBuf)->cksum = 0; ((ICMP_HEADER*)IcmpSendBuf)->seq = htons(usSeqNo++); ((ICMP_HEADER*)IcmpSendBuf)->cksum = GenerateChecksum((USHORT*)IcmpSendBuf, sizeof(ICMP_HEADER)+DEF_ICMP_DATA_SIZE); //记录序列号和当前时间 stDecodeResult.usSeqNo = ((ICMP_HEADER*)IcmpSendBuf)->seq; stDecodeResult.dwRoundTripTime = GetTickCount(); //发送ICMP的EchoRequest数据报 if (sendto(sockRaw, IcmpSendBuf, sizeof(IcmpSendBuf), 0, (sockaddr*)&destSockAddr, sizeof(destSockAddr)) == SOCKET_ERROR) { //如果目的主机不可达则直接退出 if (WSAGetLastError() == WSAEHOSTUNREACH) cout << '\t' << "Destination host unreachable.\n" << "\nTrace complete.\n" << endl; closesocket(sockRaw); WSACleanup(); return 0; } //接收ICMP的EchoReply数据报 //因为收到的可能并非程序所期待的数据报，所以需要循环接收直到收到所要数据或超时 sockaddr_in from; int iFromLen = sizeof(from); int iReadDataLen; while (1) { //等待数据到达 iReadDataLen = recvfrom(sockRaw, IcmpRecvBuf, MAX_ICMP_PACKET_SIZE, 0, (sockaddr*)&from, &iFromLen); if (iReadDataLen != SOCKET_ERROR) //有数据包到达 { //解码得到的数据包，如果解码正确则跳出接收循环发送下一个EchoRequest包 if (DecodeIcmpResponse(IcmpRecvBuf, iReadDataLen, stDecodeResult)) { if (stDecodeResult.dwIPaddr.s_addr == destSockAddr.sin_addr.s_addr) bReachDestHost = TRUE; cout << '\t' << inet_ntoa(stDecodeResult.dwIPaddr) << endl; break; } } else if (WSAGetLastError() == WSAETIMEDOUT) //接收超时，打印星号 { cout << setw(9) << '*' << '\t' << "Request timed out." << endl; break; } else { cerr << "\nFailed to call recvfrom\n" << "error code: " << WSAGetLastError() << endl; closesocket(sockRaw); WSACleanup(); return -1; } } //TTL值加1 iTTL++; } //输出屏幕信息 cout << "\nTrace complete.\n" << endl; closesocket(sockRaw); WSACleanup(); return 0; } //产生网际校验和 USHORT GenerateChecksum(USHORT* pBuf, int iSize) { unsigned long cksum = 0; while (iSize>1) { cksum += *pBuf++; iSize -= sizeof(USHORT); } if (iSize) cksum += *(UCHAR*)pBuf; cksum = (cksum >> 16) + (cksum & 0xffff); cksum += (cksum >> 16); return (USHORT)(~cksum); } //解码得到的数据报 BOOL DecodeIcmpResponse(char* pBuf, int iPacketSize, DECODE_RESULT& stDecodeResult) { //检查数据报大小的合法性 IP_HEADER* pIpHdr = (IP_HEADER*)pBuf; int iIpHdrLen = pIpHdr->hdr_len * 4; if (iPacketSize < (int)(iIpHdrLen+sizeof(ICMP_HEADER))) return FALSE; //按照ICMP包类型检查id字段和序列号以确定是否是程序应接收的Icmp包 ICMP_HEADER* pIcmpHdr = (ICMP_HEADER*)(pBuf+iIpHdrLen); USHORT usID, usSquNo; if (pIcmpHdr->type == ICMP_ECHO_REPLY) { usID = pIcmpHdr->id; usSquNo = pIcmpHdr->seq; } else if(pIcmpHdr->type == ICMP_TIMEOUT) { char* pInnerIpHdr = pBuf+iIpHdrLen+sizeof(ICMP_HEADER); //载荷中的IP头 int iInnerIPHdrLen = ((IP_HEADER*)pInnerIpHdr)->hdr_len * 4;//载荷中的IP头长 ICMP_HEADER* pInnerIcmpHdr = (ICMP_HEADER*)(pInnerIpHdr+iInnerIPHdrLen);//载荷中的ICMP头 usID = pInnerIcmpHdr->id; usSquNo = pInnerIcmpHdr->seq; } else return FALSE; if (usID != (USHORT)GetCurrentProcessId() || usSquNo !=stDecodeResult.usSeqNo) return FALSE; //处理正确收到的ICMP数据报 if (pIcmpHdr->type == ICMP_ECHO_REPLY || pIcmpHdr->type == ICMP_TIMEOUT) { //返回解码结果 stDecodeResult.dwIPaddr.s_addr = pIpHdr->sourceIP; stDecodeResult.dwRoundTripTime = GetTickCount()-stDecodeResult.dwRoundTripTime; //打印屏幕信息 if (stDecodeResult.dwRoundTripTime) cout << setw(6) << stDecodeResult.dwRoundTripTime << " ms" << flush; else cout << setw(6) << "<1" << " ms" << flush; return TRUE; } return FALSE; }