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280 lines
9.6 KiB
C
280 lines
9.6 KiB
C
//Source: https://web.archive.org/web/20180215030743/http://www.binarytides.com/packet-sniffer-code-c-linux
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#include<stdio.h> //For standard things
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#include<stdlib.h> //malloc
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#include<string.h> //memset
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#include<netinet/ip_icmp.h> //Provides declarations for icmp header
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#include<netinet/udp.h> //Provides declarations for udp header
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#include<netinet/tcp.h> //Provides declarations for tcp header
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#include<netinet/ip.h> //Provides declarations for ip header
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#include<sys/socket.h>
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#include<arpa/inet.h>
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void ProcessPacket(unsigned char* , int);
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void print_ip_header(unsigned char* , int);
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void print_tcp_packet(unsigned char* , int);
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void print_udp_packet(unsigned char * , int);
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void print_icmp_packet(unsigned char* , int);
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void PrintData (unsigned char* , int);
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int sock_raw;
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FILE *logfile;
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int tcp=0,udp=0,icmp=0,others=0,igmp=0,total=0,i,j;
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struct sockaddr_in source,dest;
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int main()
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{
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int saddr_size , data_size;
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struct sockaddr saddr;
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struct in_addr in;
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unsigned char *buffer = (unsigned char *)malloc(65536); //Its Big!
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logfile=fopen("log.txt","w");
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if(logfile==NULL) printf("Unable to create file.");
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printf("Starting...\n");
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//Create a raw socket that shall sniff
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sock_raw = socket(PF_INET, SOCK_RAW, IPPROTO_UDP);
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if(sock_raw < 0)
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{
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printf("Socket Error\n");
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return 1;
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}
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while(1)
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{
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saddr_size = sizeof saddr;
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//Receive a packet
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data_size = recvfrom(sock_raw , buffer , 65536 , 0 , &saddr , &saddr_size);
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if(data_size <0 )
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{
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printf("Recvfrom error , failed to get packets\n");
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return 1;
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}
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//Now process the packet
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ProcessPacket(buffer , data_size);
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}
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close(sock_raw);
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printf("Finished");
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return 0;
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}
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void ProcessPacket(unsigned char* buffer, int size)
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{
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//Get the IP Header part of this packet
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struct iphdr *iph = (struct iphdr*)buffer;
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++total;
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switch (iph->protocol) //Check the Protocol and do accordingly...
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{
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case 1: //ICMP Protocol
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++icmp;
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//PrintIcmpPacket(Buffer,Size);
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break;
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case 2: //IGMP Protocol
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++igmp;
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break;
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case 6: //TCP Protocol
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++tcp;
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print_tcp_packet(buffer , size);
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break;
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case 17: //UDP Protocol
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++udp;
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print_udp_packet(buffer , size);
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break;
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default: //Some Other Protocol like ARP etc.
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++others;
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break;
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}
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printf("TCP : %d UDP : %d ICMP : %d IGMP : %d Others : %d Total : %d\r",tcp,udp,icmp,igmp,others,total);
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}
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void print_ip_header(unsigned char* Buffer, int Size)
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{
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unsigned short iphdrlen;
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struct iphdr *iph = (struct iphdr *)Buffer;
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iphdrlen =iph->ihl*4;
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memset(&source, 0, sizeof(source));
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source.sin_addr.s_addr = iph->saddr;
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memset(&dest, 0, sizeof(dest));
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dest.sin_addr.s_addr = iph->daddr;
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fprintf(logfile,"\n");
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fprintf(logfile,"IP Header\n");
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fprintf(logfile," |-IP Version : %d\n",(unsigned int)iph->version);
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fprintf(logfile," |-IP Header Length : %d DWORDS or %d Bytes\n",(unsigned int)iph->ihl,((unsigned int)(iph->ihl))*4);
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fprintf(logfile," |-Type Of Service : %d\n",(unsigned int)iph->tos);
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fprintf(logfile," |-IP Total Length : %d Bytes(Size of Packet)\n",ntohs(iph->tot_len));
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fprintf(logfile," |-Identification : %d\n",ntohs(iph->id));
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//fprintf(logfile," |-Reserved ZERO Field : %d\n",(unsigned int)iphdr->ip_reserved_zero);
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//fprintf(logfile," |-Dont Fragment Field : %d\n",(unsigned int)iphdr->ip_dont_fragment);
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//fprintf(logfile," |-More Fragment Field : %d\n",(unsigned int)iphdr->ip_more_fragment);
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fprintf(logfile," |-TTL : %d\n",(unsigned int)iph->ttl);
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fprintf(logfile," |-Protocol : %d\n",(unsigned int)iph->protocol);
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fprintf(logfile," |-Checksum : %d\n",ntohs(iph->check));
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fprintf(logfile," |-Source IP : %s\n",inet_ntoa(source.sin_addr));
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fprintf(logfile," |-Destination IP : %s\n",inet_ntoa(dest.sin_addr));
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}
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void print_tcp_packet(unsigned char* Buffer, int Size)
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{
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unsigned short iphdrlen;
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struct iphdr *iph = (struct iphdr *)Buffer;
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iphdrlen = iph->ihl*4;
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struct tcphdr *tcph=(struct tcphdr*)(Buffer + iphdrlen);
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fprintf(logfile,"\n\n***********************TCP Packet*************************\n");
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print_ip_header(Buffer,Size);
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fprintf(logfile,"\n");
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fprintf(logfile,"TCP Header\n");
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fprintf(logfile," |-Source Port : %u\n",ntohs(tcph->source));
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fprintf(logfile," |-Destination Port : %u\n",ntohs(tcph->dest));
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fprintf(logfile," |-Sequence Number : %u\n",ntohl(tcph->seq));
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fprintf(logfile," |-Acknowledge Number : %u\n",ntohl(tcph->ack_seq));
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fprintf(logfile," |-Header Length : %d DWORDS or %d BYTES\n" ,(unsigned int)tcph->doff,(unsigned int)tcph->doff*4);
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//fprintf(logfile," |-CWR Flag : %d\n",(unsigned int)tcph->cwr);
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//fprintf(logfile," |-ECN Flag : %d\n",(unsigned int)tcph->ece);
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fprintf(logfile," |-Urgent Flag : %d\n",(unsigned int)tcph->urg);
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fprintf(logfile," |-Acknowledgement Flag : %d\n",(unsigned int)tcph->ack);
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fprintf(logfile," |-Push Flag : %d\n",(unsigned int)tcph->psh);
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fprintf(logfile," |-Reset Flag : %d\n",(unsigned int)tcph->rst);
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fprintf(logfile," |-Synchronise Flag : %d\n",(unsigned int)tcph->syn);
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fprintf(logfile," |-Finish Flag : %d\n",(unsigned int)tcph->fin);
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fprintf(logfile," |-Window : %d\n",ntohs(tcph->window));
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fprintf(logfile," |-Checksum : %d\n",ntohs(tcph->check));
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fprintf(logfile," |-Urgent Pointer : %d\n",tcph->urg_ptr);
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fprintf(logfile,"\n");
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fprintf(logfile," DATA Dump ");
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fprintf(logfile,"\n");
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fprintf(logfile,"IP Header\n");
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PrintData(Buffer,iphdrlen);
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fprintf(logfile,"TCP Header\n");
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PrintData(Buffer+iphdrlen,tcph->doff*4);
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fprintf(logfile,"Data Payload\n");
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PrintData(Buffer + iphdrlen + tcph->doff*4 , (Size - tcph->doff*4 - iph->ihl*4) );
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fprintf(logfile,"\n###########################################################");
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}
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void print_udp_packet(unsigned char *Buffer , int Size)
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{
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unsigned short iphdrlen;
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struct iphdr *iph = (struct iphdr *)Buffer;
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iphdrlen = iph->ihl*4;
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struct udphdr *udph = (struct udphdr*)(Buffer + iphdrlen);
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fprintf(logfile,"\n\n***********************UDP Packet*************************\n");
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print_ip_header(Buffer,Size);
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fprintf(logfile,"\nUDP Header\n");
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fprintf(logfile," |-Source Port : %d\n" , ntohs(udph->source));
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fprintf(logfile," |-Destination Port : %d\n" , ntohs(udph->dest));
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fprintf(logfile," |-UDP Length : %d\n" , ntohs(udph->len));
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fprintf(logfile," |-UDP Checksum : %d\n" , ntohs(udph->check));
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fprintf(logfile,"\n");
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fprintf(logfile,"IP Header\n");
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PrintData(Buffer , iphdrlen);
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fprintf(logfile,"UDP Header\n");
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PrintData(Buffer+iphdrlen , sizeof udph);
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fprintf(logfile,"Data Payload\n");
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PrintData(Buffer + iphdrlen + sizeof udph ,( Size - sizeof udph - iph->ihl * 4 ));
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fprintf(logfile,"\n###########################################################");
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}
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void print_icmp_packet(unsigned char* Buffer , int Size)
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{
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unsigned short iphdrlen;
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struct iphdr *iph = (struct iphdr *)Buffer;
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iphdrlen = iph->ihl*4;
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struct icmphdr *icmph = (struct icmphdr *)(Buffer + iphdrlen);
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fprintf(logfile,"\n\n***********************ICMP Packet*************************\n");
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print_ip_header(Buffer , Size);
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fprintf(logfile,"\n");
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fprintf(logfile,"ICMP Header\n");
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fprintf(logfile," |-Type : %d",(unsigned int)(icmph->type));
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if((unsigned int)(icmph->type) == 11)
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fprintf(logfile," (TTL Expired)\n");
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else if((unsigned int)(icmph->type) == ICMP_ECHOREPLY)
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fprintf(logfile," (ICMP Echo Reply)\n");
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fprintf(logfile," |-Code : %d\n",(unsigned int)(icmph->code));
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fprintf(logfile," |-Checksum : %d\n",ntohs(icmph->checksum));
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//fprintf(logfile," |-ID : %d\n",ntohs(icmph->id));
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//fprintf(logfile," |-Sequence : %d\n",ntohs(icmph->sequence));
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fprintf(logfile,"\n");
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fprintf(logfile,"IP Header\n");
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PrintData(Buffer,iphdrlen);
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fprintf(logfile,"UDP Header\n");
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PrintData(Buffer + iphdrlen , sizeof icmph);
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fprintf(logfile,"Data Payload\n");
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PrintData(Buffer + iphdrlen + sizeof icmph , (Size - sizeof icmph - iph->ihl * 4));
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fprintf(logfile,"\n###########################################################");
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}
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void PrintData (unsigned char* data , int Size)
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{
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for(i=0 ; i < Size ; i++)
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{
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if( i!=0 && i%16==0) //if one line of hex printing is complete...
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{
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fprintf(logfile," ");
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for(j=i-16 ; j<i ; j++)
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{
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if(data[j]>=32 && data[j]<=128)
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fprintf(logfile,"%c",(unsigned char)data[j]); //if its a number or alphabet
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else fprintf(logfile,"."); //otherwise print a dot
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}
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fprintf(logfile,"\n");
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}
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if(i%16==0) fprintf(logfile," ");
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fprintf(logfile," %02X",(unsigned int)data[i]);
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if( i==Size-1) //print the last spaces
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{
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for(j=0;j<15-i%16;j++) fprintf(logfile," "); //extra spaces
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fprintf(logfile," ");
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for(j=i-i%16 ; j<=i ; j++)
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{
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if(data[j]>=32 && data[j]<=128) fprintf(logfile,"%c",(unsigned char)data[j]);
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else fprintf(logfile,".");
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}
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fprintf(logfile,"\n");
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}
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}
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}
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