#include <stdio.h> #include <arpa/inet.h> #include <unistd.h> #include <netinet/ip.h> #include <errno.h> #include <string.h> #include <iostream> using namespace std; char g_testDomain[32] = "www.baidu.com."; int g_dstPort = 53; struct IPHeader { unsigned char headerLen:4; unsigned char version:4; unsigned char tos; //service type unsigned short totalLen; //total length unsigned short id; //identity unsigned short flagOffset; //3-bit flag + 13-bit slice offset unsigned char ttl; //TTL unsigned char protocol; //protocol unsigned short checksum; //header checksum unsigned int srcIP; //source IP address unsigned int dstIP; //destination IP address }; struct UDPHeader //Define UDP header { unsigned short srcPort; //16-bit source port unsigned short dstPort; //16-bit destination port unsigned short dataLen;//16-bit UDP packet length unsigned short checksum;//16-bit checksum }; struct DNSHeader { unsigned short id;// unsigned short bitHeader; //Protocol header unsigned short questionCount;//Total number of requested questions unsigned short answerCount;//Total number of answers unsigned short authorityCount;//Total number of authorizations unsigned short additionalCount;//Additional total }; struct DNSQuery { unsigned short queryType; //The resource record type of the query. unsigned short queryClass; //Specify the protocol group of the information. }; struct DNS { DNSHeader header; char* domainStr; DNSQuery query; }; enum DNSType //The type of resource record to query. { DNSType_A=0x01,//Specify the computer IP address DNSType_NS=0x02, //Specify the DNS name server used to name the zone. DNSType_MD=0x03, //Specify the mail receiving station (this type is outdated, use MX instead) DNSType_MF=0x04, //Specify the mail transfer station (this type is outdated, use MX instead) DNSType_CNAME=0x05, //Specify the canonical name used for the alias. DNSType_SOA=0x06, //Specify the "starting authority" for the DNS zone. DNSType_MB=0x07, //Specify the email domain name. DNSType_MG=0x08, //Specify the members of the mail group. DNSType_MR=0x09, //Specify mail rename domain name. DNSType_NULL=0x0A, //Specify an empty resource record DNSType_WKS=0x0B, //Describe known services. DNSType_PTR=0x0C, //If the query is an IP address, specify the computer name; otherwise, specify a pointer to other information. DNSType_HINFO=0x0D, //Specify the computer CPU and operating system type. DNSType_MINFO=0x0E, //Specify mailbox or mailing list information. DNSType_MX=0x0F, //Specify the mail exchanger. DNSType_TXT=0x10, //Specify text information. DNSType_UINFO=0x64, //Specify user information. DNSType_UID=0x65, //Specify the user identifier. DNSType_GID=0x66, //Specify the group identifier of the group name. DNSType_ANY=0xFF //Specify all data types. }; enum DNSClass //Protocol group for specifying information. { DNSClass_IN=0x01, //Specify the Internet class. DNSClass_CSNET=0x02, //Specify the CSNET class. (obsolete) DNSClass_CHAOS=0x03, //Specify Chaos class. DNSClass_HESIOD=004,//Specify the MIT Athena Hesiod class. DNSClass_ANY=0xFF //Specify any previously listed wildcards. }; //udp checksum unsigned short udpChecksum(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); //Add high 16bit and low 16bit cksum += (cksum>>16); //Add the 16bit of the carry to the high order and the low 16bit return (unsigned short)(~cksum); } //ip number to string void ipLLToStr(long long ip_num,char* ip_str) { unsigned int iptok1 = (ip_num & 0xFF000000) >> 24; unsigned int iptok2 = (ip_num & 0x00FF0000) >> 16; unsigned int iptok3 = (ip_num & 0x0000FF00) >> 8; unsigned int iptok4 = ip_num & 0x000000FF; char ip[32]; bzero(ip,sizeof(ip)); snprintf(ip,sizeof(ip),"%d.%d.%d.%d",iptok1,iptok2,iptok3,iptok4); strcpy(ip_str,ip); } //Send DNS message void sendDnsPacket(int sockfd,sockaddr_in* dstAddr,bool useEDns) { char sendBuf[1024] = ""; DNS requestDNS; bzero(&requestDNS,sizeof(requestDNS)); int domainLen = strlen(g_testDomain)+1; int dnsDataLen = sizeof(requestDNS.header)+sizeof(requestDNS.query)+domainLen; int totalLen = sizeof(IPHeader) + sizeof(UDPHeader) + dnsDataLen; int pos = 0; IPHeader* ipHeader = (IPHeader *)sendBuf; ipHeader->headerLen = sizeof(IPHeader)>>2; ipHeader->version = IPVERSION; //Service type ipHeader->tos = 0; ipHeader->totalLen = totalLen; ipHeader->id=0; //Set the flag to 0 ipHeader->flagOffset=0; //The protocol used is the DNS protocol ipHeader->protocol=IPPROTO_UDP; // How long a packet can live on the network ipHeader->ttl=64; //Destination address //ipHeader->srcIP = inet_addr("1.1.1.1"); //If you want to forge the source IP... ipHeader->dstIP = dstAddr->sin_addr.s_addr; pos = sizeof(IPHeader); UDPHeader* udpHeader = (UDPHeader*)(sendBuf+pos); udpHeader->srcPort = htons(21000); udpHeader->dstPort = htons(g_dstPort); udpHeader->dataLen = htons(totalLen-sizeof(IPHeader)); pos+= sizeof(UDPHeader); requestDNS.header.id = 10; requestDNS.header.bitHeader = htons(0x0100); requestDNS.header.questionCount = htons(1); if(useEDns){ requestDNS.header.additionalCount = htons(1); } requestDNS.domainStr = new char[domainLen]; bzero(requestDNS.domainStr,domainLen); char *priorPtr = g_testDomain; char *currPtr = strstr(g_testDomain,"."); int dotPos = 0; while(currPtr!=NULL) { int size = currPtr - priorPtr; requestDNS.domainStr[dotPos] = size; dotPos ++; memcpy(requestDNS.domainStr+dotPos,priorPtr,size); dotPos += size; currPtr++; priorPtr = currPtr; currPtr = strstr(g_testDomain+dotPos,"."); if(currPtr==NULL) { size = strlen(g_testDomain) - dotPos; requestDNS.domainStr[dotPos] = size; dotPos ++; memcpy(requestDNS.domainStr+dotPos,priorPtr,size); requestDNS.domainStr[domainLen-1] = '\0'; } } requestDNS.query.queryType = htons(1); requestDNS.query.queryClass = htons(1); memcpy(sendBuf+pos,&requestDNS.header,sizeof(requestDNS.header)); pos += sizeof(requestDNS.header); memcpy(sendBuf+pos,requestDNS.domainStr,domainLen); pos += domainLen; memcpy(sendBuf+pos,&requestDNS.query,sizeof(requestDNS.query)); udpHeader->checksum = udpChecksum((unsigned short*)(sendBuf+sizeof(IPHeader) + sizeof(UDPHeader)), dnsDataLen); if(sendto(sockfd,sendBuf,totalLen,0,(struct sockaddr *)dstAddr,sizeof(*dstAddr))<0){ perror("sendto error"); } } //parse dns result bool decodeDNSResult(const char *buf, int& index,char* dst) { if (buf == NULL){ return false; } int i = 0; unsigned char len = 0; bool skip0x = true; while ( (len = buf[index]) != 0x00) { if ((len & 0xc0) == 0) //normal format, LabelDataLen + Label { index++;//Skip len memcpy(dst+i,buf+index,len); i + = len; index + = only; strcat(dst,"."); i++; continue; } //Message compression format, 11000000 00000000, two bytes, the first 2 bits are the jump flag, and the last 14 bits are the jump offset short test = 0; memcpy(&test,buf+index,2); int jumpIndex = ntohs(test) & 0x3fff; index++; index++;//Skip len skip0x = false; if (!decodeDNSResult(buf,jumpIndex,dst+i)){ return false; } break; } if(skip0x){ index++;//Skip 0x00 } return true; } // resolve dns question void parseDNSQuestion(const char* recvBuf,int& pos,int questionCount) { char contentStr[2048] = ""; for(int i = 0;i<questionCount;i++) { //domain char tmp[512]; bzero(tmp,sizeof(tmp)); decodeDNSResult(recvBuf,pos,tmp); //query type unsigned short queryType = 0; memcpy(&queryType,recvBuf+pos,sizeof(queryType)); pos += sizeof(queryType); queryType = ntohs(queryType); //query class unsigned short queryClass = 0; memcpy(&queryClass,recvBuf+pos,sizeof(queryClass)); pos += sizeof(queryClass); queryClass = ntohs(queryClass); char tmpStr[1024] = ""; snprintf(tmpStr,sizeof(tmpStr),"%s type:%d class:%d\n",tmp,queryType,queryClass); strcat(contentStr,tmpStr); } if(questionCount>0){ cout << contentStr << endl; } } //parse dns result void parseResult( const char *recvBuf, int &pos,int count) { char contentStr[2048] = ""; for(int i=0;i<count;i++) { //domain char domainStr[512]; bzero(domainStr,sizeof(domainStr)); decodeDNSResult(recvBuf,pos,domainStr); //answer type unsigned short dnsType = 0; memcpy(&dnsType,recvBuf+pos,sizeof(dnsType)); pos += sizeof(dnsType); dnsType = ntohs(dnsType); //answer class unsigned short dnsClass = 0; memcpy(&dnsClass,recvBuf+pos,sizeof(dnsClass)); pos += sizeof(dnsClass); dnsClass = ntohs(dnsClass); //answer ttl int dnsTTL = 0; memcpy(&dnsTTL,recvBuf+pos,sizeof(dnsTTL)); pos += sizeof(dnsTTL); dnsTTL = ntohl(dnsTTL); //answer data len unsigned short answerDataLen = 0; memcpy(&answerDataLen,recvBuf+pos,sizeof(answerDataLen)); pos += sizeof(answerDataLen); answerDataLen = ntohs(answerDataLen); //ip cname char tmpStr[1024] = ""; if(dnsType==DNSType_A) { unsigned long ip = 0; memcpy(&ip,recvBuf+pos,sizeof(ip)); pos += sizeof(ip); ip = ntohl(ip); char ipStr[32]; bzero(ipStr,sizeof(ipStr)); ipLLToStr (ip, ipStr); snprintf(tmpStr,sizeof(tmpStr),"%s ttl:%d type:%d class:%d %s\n",domainStr,dnsTTL,dnsType,dnsClass,ipStr); strcat(contentStr,tmpStr); }else if(dnsType==DNSType_CNAME||dnsType==DNSType_NS) { char cname[512]; bzero(cname,sizeof(cname)); decodeDNSResult(recvBuf,pos,cname); snprintf(tmpStr,sizeof(tmpStr),"%s ttl:%d type:%d class:%d %s\n",domainStr,dnsTTL,dnsType,dnsClass,cname); strcat(contentStr,tmpStr); } } if(count>0){ cout << contentStr << endl; } } // Parse the dns package void parseDnsPacket(int sockfd,sockaddr_in* dstAddr) { char recvBuf[10240] = ""; socklen_t cliLen = sizeof(dstAddr); int recvLen = recvfrom(sockfd,recvBuf,sizeof(recvBuf),0,(sockaddr*)&dstAddr,&cliLen); if( recvLen > 0) { int pos = 0; IPHeader* ipHeader = (IPHeader *)recvBuf; pos += sizeof(IPHeader); char srcIPStr[64] = "",dstIPStr[64]=""; ipLLToStr(ntohl(ipHeader->srcIP),srcIPStr); ipLLToStr(ntohl(ipHeader->dstIP),dstIPStr); int totalLen = ntohs(ipHeader->totalLen); char ipHeaderStr[256] = ""; snprintf(ipHeaderStr,sizeof(ipHeaderStr),"response ip header info: version:%d,tos:%d,protocol:%d,ttl:%d,srcIP:%s,dstIP:%s,totalLen:%d" ,ipHeader->version,ipHeader->tos,ipHeader->protocol,ipHeader->ttl,srcIPStr,dstIPStr,totalLen); cout << ipHeaderStr << endl; UDPHeader* udpHeader = (UDPHeader*)(recvBuf+pos); pos += sizeof(UDPHeader); unsigned short udpSrcPort = ntohs(udpHeader->srcPort); unsigned short udpDstPort = ntohs(udpHeader->dstPort); unsigned short udpLen = ntohs(udpHeader->dataLen); char udpHeaderStr[256] = ""; snprintf(udpHeaderStr,sizeof(udpHeaderStr),"response udp header:srcPort:%d,dstPort:%d,udpLen:%d",udpSrcPort,udpDstPort,udpLen); cout << udpHeaderStr << endl; DNSHeader* dnsHeader = (DNSHeader*)(recvBuf+pos); dnsHeader-> bitHeader = ntohs (dnsHeader-> bitHeader); dnsHeader->answerCount = ntohs(dnsHeader->answerCount); dnsHeader->additionalCount = ntohs(dnsHeader->additionalCount); dnsHeader->authorityCount = ntohs(dnsHeader->authorityCount); dnsHeader->questionCount = ntohs(dnsHeader->questionCount); int dnsStartPos = sizeof(DNSHeader); // Parse the question parseDNSQuestion(recvBuf+pos,dnsStartPos,dnsHeader->questionCount); //parse answer parseResult(recvBuf+pos,dnsStartPos,dnsHeader->answerCount); // Parse authorization parseResult(recvBuf+pos,dnsStartPos,dnsHeader->authorityCount); //parse additional parseResult(recvBuf+pos,dnsStartPos,dnsHeader->additionalCount); } } intmain() { int sockfd = socket (AF_INET, SOCK_RAW, IPPROTO_UDP); if( sockfd < 0) { cout << strerror(errno) << endl; return -1; } int bufSize=50*1024; setsockopt(sockfd,SOL_SOCKET,SO_RCVBUF,&bufSize,sizeof(bufSize) ); //IPPROTO_TP indicates that the user fills in the IP packet by himself //IP_HDRINCL means that the kernel calculates the header checksum of the IP packet and fills the id of that IP int on = 1; setsockopt(sockfd,IPPROTO_IP,IP_HDRINCL,&on,sizeof(on)); char dstStr[32] = "114.114.114.114"; sockaddr_in dstAddr; bzero(&dstAddr,sizeof(dstAddr)); dstAddr.sin_family = AF_INET; dstAddr.sin_addr.s_addr = inet_addr(dstStr); dstAddr.sin_port = htons(g_dstPort); sendDnsPacket(sockfd,&dstAddr,false); parseDnsPacket(sockfd,&dstAddr); close(sockfd); return 0; } response ip header info: version:4,tos:0,protocol:17,ttl:142,srcIP:114.114.114.114,dstIP:172.16.96.52,totalLen:118 response udp header:srcPort:53,dstPort:21000,udpLen:98 www.baidu.com. type:1 class:1 www.baidu.com. ttl:0 type:5 class:1 www.a.shifen.com. www.a.shifen.com. ttl:164 type:1 class:1 220.181.112.244 www.a.shifen.com. ttl:164 type:1 class:1 220.181.111.188
rawsocket sends dns packets
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