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Parts of example codes

Parts of example codes. Some useful structures. ConnectionList<State> “ constate.h ” TCPState “ tcpstate.h ” ConnectionToStateMapping<State> “ constate.h ” IPHeader “ ip.h ” TCPHeader “ tcp.h ” Connection “ sockint.h ”.

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Parts of example codes

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  1. Parts of example codes

  2. Some useful structures • ConnectionList<State> “constate.h” • TCPState “tcpstate.h” • ConnectionToStateMapping<State> “constate.h” • IPHeader “ip.h” • TCPHeader “tcp.h” • Connection “sockint.h”

  3. void craftPacketHeader(Packet *psend,ConnectionToStateMapping<TCPState> conState, TCPHeader th, int type, unsigned short no_of_bytes ) • { • //Packet psend; • Connection c = conState.connection; • IPHeader ih; • TCPHeader tcph; • unsigned short totalLength = no_of_bytes ; • unsigned int acknum,seqnum; • unsigned char flag=0; • unsigned short winsize,up; • TCPOptions opt; • unsigned int time = Time(); • int time_offset = 4; • unsigned char hlen=5; • th.GetSeqNum(acknum);// assign value to acknum • th.GetAckNum(seqnum); • th.GetWinSize(winsize); • th.GetOptions(opt); • th.GetUrgentPtr(up); • th.GetHeaderLen(hlen); • cout<<acknum<<endl; • seqnum = conState.state.GetLastSent();

  4. if ( type == SYN_HEADER ) • { • totalLength = SYN_HEADER_LENGTH; • seqnum = conState.state.GetLastSent(); • SET_SYN(flag); • time_offset = 8; • } • else if ( type == ACK_HEADER || type == PSH_ACK_HEADER) • { • totalLength += ACK_HEADER_LENGTH; • SET_ACK(flag); • acknum = conState.state.GetLastRecvd()+ 1; • seqnum += 1; • if(type == PSH_ACK_HEADER ) • SET_PSH(flag); • } • else if ( type == FIN_ACK_HEADER ) • { • totalLength = FIN_HEADER_LENGTH; • SET_ACK(flag); • SET_FIN(flag); • acknum = conState.state.GetLastRecvd() + 1; • seqnum += 1; • } • else if ( type == SYN_ACK_HEADER ) • { • totalLength = SYN_HEADER_LENGTH; • seqnum = conState.state.GetLastSent(); • acknum = conState.state.GetLastRecvd() + 1; • SET_ACK(flag); • SET_SYN(flag); • time_offset = 8; • }

  5. ih.SetProtocol(IP_PROTO_TCP); • ih.SetSourceIP(c.src); • ih.SetDestIP(c.dest); • ih.SetTotalLength( totalLength ); • // push it onto the packet • (*psend).PushFrontHeader(ih); • tcph.SetDestPort(c.destport,(*psend)); • tcph.SetSourcePort(c.srcport,(*psend)); • tcph.SetAckNum(acknum,(*psend)); • tcph.SetSeqNum(seqnum,(*psend)); • tcph.SetFlags(flag,(*psend)); • tcph.SetWinSize(winsize-12,(*psend)); • memcpy((void *)(opt.data+time_offset+4),(void *)(opt.data+time_offset),4); • *(int *)(opt.data+time_offset) = htonl(time); • tcph.SetOptions(opt); • tcph.SetUrgentPtr(up,(*psend)); • tcph.SetHeaderLen(hlen,(*psend)); • tcph.RecomputeChecksum((*psend)); • // Now we want to have the tcp header BEHIND the IP header • (*psend).PushBackHeader(tcph); • tcph.Print(cout); • //return psend; • }

  6. Notice • Pls make your codes well commented.

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