TCP-Traceroute 核心代码

测试环境:

操作系统: Microsoft Windows 2000 with Service Pack 4
开发环境: Microsoft Visual C++6 with Service Pack 6
其它: Winpcap 3.1 beta 3

代码

//tracer.c //Copyright (c) 1999 - 2004 //S8S8.net Network Tech. Forum //written by '13th Floor' //All rights reserved. #include <winsock2.h> #include <ws2tcpip.h> #include <cstring> #include <queue> using namespace std; #include "pcap.h" #include "headers.h" #include "tracer.h" char* FLT_EXPR = "ip and icmp[icmptype]=icmp-timxceed or tcp[tcpflags]=tcp-rst"; unsigned short checksum(unsigned short *buffer, int size) { unsigned long cksum = 0; while(size > 1) { cksum += *buffer++; size -= sizeof(unsigned short); } if(size) cksum += *(unsigned char*)buffer; cksum = (cksum >> 16) + (cksum & 0xffff); cksum += (cksum >> 16); return (unsigned short)(~cksum); } int build_packets( unsigned long local_addr, unsigned long dst_addr, char* buf, unsigned char TTL) { static unsigned long SEQ = 0x2344512; int datasize =0; IP_HDR ip_header; TCP_HDR tcp_header; PSD_HDR psd_header; ip_header.h_verlen = (4 << 4 | sizeof(ip_header) / sizeof(unsigned long)); ip_header.total_len = htons(sizeof(IP_HDR) + sizeof(TCP_HDR)); ip_header.ident = 1; ip_header.frag_and_flags = 0; ip_header.ttl = TTL; ip_header.proto = IPPROTO_TCP; ip_header.checksum = 0; ip_header.saddr = local_addr; ip_header.daddr = dst_addr; tcp_header.th_sport = htons(7000); tcp_header.th_dport = htons(5000); tcp_header.th_seq = SEQ++; tcp_header.th_ack = 0; tcp_header.th_lenres = (sizeof(TCP_HDR) / 4 << 4 | 0); tcp_header.th_flag = 16; tcp_header.th_win = htons(16384); tcp_header.th_urp = 0; tcp_header.th_sum = 0; psd_header.saddr = ip_header.saddr; psd_header.daddr = ip_header.daddr; psd_header.mbz = 0; psd_header.proto = IPPROTO_TCP; psd_header.tcpl = htons(sizeof(tcp_header)); memcpy(buf, &psd_header, sizeof(psd_header)); memcpy(buf + sizeof(psd_header), &tcp_header, sizeof(tcp_header)); tcp_header.th_sum = checksum((unsigned short *)buf, sizeof(psd_header) + sizeof(tcp_header)); memcpy(buf, &ip_header, sizeof(ip_header)); memcpy(buf + sizeof(ip_header), &tcp_header, sizeof(tcp_header)); memset(buf + sizeof(ip_header) + sizeof(tcp_header), 0, 4); datasize = sizeof(ip_header) + sizeof(tcp_header); ip_header.checksum = checksum((unsigned short*)buf,datasize); memcpy(buf, &ip_header, sizeof(ip_header)); return 0; } int start_trace( queue<unsigned long>& dst_addr_queue, unsigned long local_addr, SOCKET& socket) { char snd_buf[128]; int ret; sockaddr_in dst_addr; pcap_t* adhandle; struct pcap_pkthdr *header; const u_char *pkt_data; //Setup for winpcap pcap_if_t *alldevs, *d; char errbuf[PCAP_ERRBUF_SIZE]; unsigned int netmask; bpf_program fcode; if (pcap_findalldevs(&alldevs, errbuf) == -1) throw ("Error in pcap_findalldevs"); try { d = alldevs->next; if ((adhandle= pcap_open_live( d->name, //adapter 65536, 1, 1000, //time out errbuf)) == NULL) throw ("Failed to open adapter!"); if(d->addresses != NULL) netmask=((struct sockaddr_in *) (d->addresses->netmask)) ->sin_addr.S_un.S_addr; else netmask=0xffffff; if(pcap_compile(adhandle, &fcode, FLT_EXPR, 1, netmask) <0 ) throw ("Failed to compile the filter"); if(pcap_setfilter(adhandle, &fcode)<0) { throw ("Error setting the filter"); } } catch (const char * error) { pcap_freealldevs(alldevs); throw (error); } pcap_freealldevs(alldevs); //Setup for Winsock WSADATA wsaData; BOOL flag = TRUE; int time_out = 2000; socket = INVALID_SOCKET; if (WSAStartup(MAKEWORD(2, 1), &wsaData) !=0) throw ("WSAStartup() failed"); try { socket = WSASocket(AF_INET, SOCK_RAW, IPPROTO_RAW, NULL,0, WSA_FLAG_OVERLAPPED); if (socket == INVALID_SOCKET) throw ("WSASocket() failed"); if (setsockopt(socket, IPPROTO_IP, IP_HDRINCL, (char*)&flag, sizeof(int)) == SOCKET_ERROR) throw ("Failed to set IP_HDRINCL"); if (setsockopt(socket, SOL_SOCKET, SO_SNDTIMEO, (char*)&time_out, sizeof(time_out)) == SOCKET_ERROR) throw ("Failed to set SO_SNDTIMEO"); } catch(const char* error) { if (socket != INVALID_SOCKET) closesocket(socket); WSACleanup(); throw error; } //Get local address char name[255]; PHOSTENT hostinfo; if (gethostname(name, sizeof(name))==0) if ((hostinfo = gethostbyname(name)) !=NULL) local_addr = (*(struct in_addr*) *hostinfo->h_addr_list).s_addr; //Start Trace while (dst_addr_queue.empty() == false) { unsigned long crt_addr = dst_addr_queue.front(); memset(&dst_addr, 0, sizeof(dst_addr)); dst_addr.sin_family = AF_INET; dst_addr.sin_addr.s_addr = crt_addr; printf("/n/nTracing: "); printf("%s/n", inet_ntoa(*(in_addr*)&crt_addr)); for (unsigned char ttl = 1; ttl <= 30; ttl++) { build_packets(local_addr, crt_addr, snd_buf, ttl); ret = sendto(socket, snd_buf, sizeof(IP_HDR)+sizeof(TCP_HDR), 0, (sockaddr*)&dst_addr, sizeof(dst_addr)); ret = pcap_next_ex(adhandle, &header, &pkt_data); if (ret == 0) { printf("%s/n", "time out"); continue; } IP_HDR* iphdr = (IP_HDR*)(pkt_data + 14); printf("%s/n", inet_ntoa(*(in_addr*)&(iphdr->saddr))); if (iphdr->proto == IPPROTO_TCP) break; } dst_addr_queue.pop(); } return 0; }

//headers.h
//Copyright (c) 1999 - 2004
//S8S8.net Network Tech. Forum
//written by '13th Floor'
//All rights reserved.

#ifndef _HEADERS_H
#define _HEADERS_H

//IP Header
typedef struct _iphdr {
unsigned char h_verlen; //IP Version
unsigned char tos; //Type of Service; 8 bits
unsigned short total_len; //total length; 16 bits
unsigned short ident; //Identification; 16 bits
unsigned short frag_and_flags; //Flags
unsigned char ttl; //Time to live; 8 bits
unsigned char proto; //Protocol; 8 bits
unsigned short checksum; //Checksum; 16 bits
unsigned long saddr; //Source IP address; 32 bits
unsigned long daddr; //Destination IP address; 32 bits
} IP_HDR;

//PSD Header
typedef struct _psdhdr {
unsigned long saddr; //Source IP address; 32 bits
unsigned long daddr; //Destination IP address; 32 bits
unsigned char mbz; //padding
unsigned char proto; //Protocol; 8 bits
unsigned short tcpl; //TCP length; 16 bits
} PSD_HDR;

//TCP Header
typedef struct _tcphdr {
unsigned short th_sport; //Source port; 16 bits
unsigned short th_dport; //Destination port; 16 bits
unsigned long th_seq; //Sequence Number; 32 bits
unsigned long th_ack; //Acknowledgment Number; 32 bits
unsigned char th_lenres; //Data Offset / reserved
unsigned char th_flag; //ECN / Control Bits; 6 bits
unsigned short th_win; //Window; 16 bits
unsigned short th_sum; //Checksum; 16 bits
unsigned short th_urp; //Urgent Pointer; 16 bits
} TCP_HDR;

//ICMP Header
typedef struct _icmphdr {
unsigned char i_type; //ICMP Type; 8 bits
unsigned char i_code; //ICMP Code; 8 bits
unsigned short i_cksum; //ICMP header checksum; 16 bits
unsigned short i_id; //Identification; 16 bits
unsigned short i_seq; //Sequence Number; 16 bits
unsigned long timestamp; //Timestamp; 32 bits
} ICMP_HDR;

#endif