Анализ IP пакетов

//Функции вывода TCP и UDP пакетов
void PrintTcpPacket(char* Buffer, int Size)
{
    unsigned short iphdrlen;
 
    iphdr = (IPV4_HDR *)Buffer;
    iphdrlen = iphdr->ip_header_len*4;
 
    tcpheader=(TCP_HDR*)(Buffer+iphdrlen);
 
    fprintf(logfile,"\n\n***********************TCP Packet*************************\n");
 
    PrintIpHeader( Buffer );
 
    fprintf(logfile,"\n");
    fprintf(logfile,"TCP Header\n");
    fprintf(logfile," |-Source Port : %u\n",ntohs(tcpheader->source_port));
    fprintf(logfile," |-Destination Port : %u\n",ntohs(tcpheader->dest_port));
    fprintf(logfile," |-Sequence Number : %u\n",ntohl(tcpheader->sequence));
    fprintf(logfile," |-Acknowledge Number : %u\n",ntohl(tcpheader->acknowledge));
    fprintf(logfile," |-Header Length : %d DWORDS or %d BYTES\n"
    ,(unsigned int)tcpheader->data_offset,(unsigned int)tcpheader->data_offset*4);
    fprintf(logfile," |-CWR Flag : %d\n",(unsigned int)tcpheader->cwr);
    fprintf(logfile," |-ECN Flag : %d\n",(unsigned int)tcpheader->ecn);
    fprintf(logfile," |-Urgent Flag : %d\n",(unsigned int)tcpheader->urg);
    fprintf(logfile," |-Acknowledgement Flag : %d\n",(unsigned int)tcpheader->ack);
    fprintf(logfile," |-Push Flag : %d\n",(unsigned int)tcpheader->psh);
    fprintf(logfile," |-Reset Flag : %d\n",(unsigned int)tcpheader->rst);
    fprintf(logfile," |-Synchronise Flag : %d\n",(unsigned int)tcpheader->syn);
    fprintf(logfile," |-Finish Flag : %d\n",(unsigned int)tcpheader->fin);
    fprintf(logfile," |-Window : %d\n",ntohs(tcpheader->window));
    fprintf(logfile," |-Checksum : %d\n",ntohs(tcpheader->checksum));
    fprintf(logfile," |-Urgent Pointer : %d\n",tcpheader->urgent_pointer);
    fprintf(logfile,"\n");
    fprintf(logfile," DATA Dump ");
    fprintf(logfile,"\n");
 
    fprintf(logfile,"IP Header\n");
    PrintData(Buffer,iphdrlen);
 
    fprintf(logfile,"TCP Header\n");
    PrintData(Buffer+iphdrlen,tcpheader->data_offset*4);
 
    fprintf(logfile,"Data Payload\n");
    PrintData(Buffer+iphdrlen+tcpheader->data_offset*4
    ,(Size-tcpheader->data_offset*4-iphdr->ip_header_len*4));
 
    fprintf(logfile,"\n###########################################################");
}
 
void PrintUdpPacket(char *Buffer,int Size)
{
    unsigned short iphdrlen;
 
    iphdr = (IPV4_HDR *)Buffer;
    iphdrlen = iphdr->ip_header_len*4;
 
    udpheader = (UDP_HDR *)(Buffer + iphdrlen);
 
    fprintf(logfile,"\n\n***********************UDP Packet*************************\n");
 
    PrintIpHeader(Buffer);
 
    fprintf(logfile,"\nUDP Header\n");
    fprintf(logfile," |-Source Port : %d\n",ntohs(udpheader->source_port));
    fprintf(logfile," |-Destination Port : %d\n",ntohs(udpheader->dest_port));
    fprintf(logfile," |-UDP Length : %d\n",ntohs(udpheader->udp_length));
    fprintf(logfile," |-UDP Checksum : %d\n",ntohs(udpheader->udp_checksum));
 
    fprintf(logfile,"\n");
    fprintf(logfile,"IP Header\n");
 
    PrintData(Buffer,iphdrlen);
 
    fprintf(logfile,"UDP Header\n");
 
    PrintData(Buffer+iphdrlen,sizeof(UDP_HDR));
 
    fprintf(logfile,"Data Payload\n");
 
    PrintData(Buffer+iphdrlen+sizeof(UDP_HDR) ,(Size - sizeof(UDP_HDR) - iphdr->ip_header_len*4));
 
    fprintf(logfile,"\n###########################################################");
}

//Функция PrintData:
/*
    Print the hex values of the data
*/
void PrintData (char* data , int Size)
{
    char a , line[17] , c;
    int j;
 
    //loop over each character and print
    for(i=0 ; i < Size ; i++)
    {
        c = data[i];
 
        //Print the hex value for every character , with a space. Important to make unsigned
        fprintf(logfile," %.2x", (unsigned char) c);
 
        //Add the character to data line. Important to make unsigned
        a = ( c >=32 && c <=128) ? (unsigned char) c : '.';
 
        line[i%16] = a;
 
        //if last character of a line , then print the line - 16 characters in 1 line
        if( (i!=0 && (i+1)%16==0) || i == Size - 1)
        {
            line[i%16 + 1] = '\0';
 
            //print a big gap of 10 characters between hex and characters
            fprintf(logfile ,"          ");
 
            //Print additional spaces for last lines which might be less than 16 characters in length
            for( j = strlen(line) ; j < 16; j++)
            {
                fprintf(logfile , "   ");
            }
 
            fprintf(logfile , "%s \n" , line);
        }
    }
 
    fprintf(logfile , "\n");
}