void do_server(char **source_addr, char **recv_payload) {
struct sockaddr_in si_me, si_other;
int s, b, size;
socklen_t slen=sizeof(si_other);
char buffer[BUFLEN];
while(1) {
s = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
if (s<0) fatal("socket");
memset((char *) &si_me, 0, sizeof(si_me));
si_me.sin_family = AF_INET;
si_me.sin_port = htons(APPPORT);
si_me.sin_addr.s_addr = htonl(INADDR_ANY);
b = bind(s, (struct sockaddr *) &si_me, sizeof(si_me));
if (b < 0) fatal("bind");
size = recvfrom(s, buffer, BUFLEN, 0, (struct sockaddr *) &si_other, &slen);
if (size < 0) fatal("recvfrom()");
if (verify_port(buffer)){
print_ip_header(buffer);
*source_addr = get_source_addr(buffer);
*recv_payload = get_payload(buffer);
break;
}
close(s);
}
}
void print_udp_packet(unsigned char *Buffer , int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)Buffer;
iphdrlen = iph->ihl*4;
struct udphdr *udph = (struct udphdr*)(Buffer + iphdrlen);
fprintf(logfile,"\n\n***********************UDP Packet*************************\n");
print_ip_header(Buffer,Size);
fprintf(logfile,"\nUDP Header\n");
fprintf(logfile," |-Source Port : %d\n" , ntohs(udph->source));
fprintf(logfile," |-Destination Port : %d\n" , ntohs(udph->dest));
fprintf(logfile," |-UDP Length : %d\n" , ntohs(udph->len));
fprintf(logfile," |-UDP Checksum : %d\n" , ntohs(udph->check));
fprintf(logfile,"\n");
fprintf(logfile,"IP Header\n");
PrintData(Buffer , iphdrlen);
fprintf(logfile,"UDP Header\n");
PrintData(Buffer+iphdrlen , sizeof udph);
fprintf(logfile,"Data Payload\n");
PrintData(Buffer + iphdrlen + sizeof udph ,( Size - sizeof udph - iph->ihl * 4 ));
fprintf(logfile,"\n###########################################################");
}
void ProcessPacket(unsigned char* buffer, int size)
{
//Get the IP Header part of this packet
struct iphdr *iph = (struct iphdr*)buffer;
if(iph->protocol==17)
{
print_udp_packet(buffer , size);
}
else
print_ip_header(buffer,size);
}
void print_icmp_packet(const u_char * Buffer , int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)(Buffer + sizeof(struct ethhdr));
iphdrlen = iph->ihl * 4;
struct icmphdr *icmph = (struct icmphdr *)(Buffer + iphdrlen + sizeof(struct ethhdr));
int header_size = sizeof(struct ethhdr) + iphdrlen + sizeof icmph;
fprintf(logfile , "\n\n***********************ICMP Packet*************************\n");
print_ip_header(Buffer , Size);
fprintf(logfile , "\n");
fprintf(logfile , "ICMP Header\n");
fprintf(logfile , " |-Type : %d",(unsigned int)(icmph->type));
if((unsigned int)(icmph->type) == 11)
{
fprintf(logfile , " (TTL Expired)\n");
}
else if((unsigned int)(icmph->type) == ICMP_ECHOREPLY)
{
fprintf(logfile , " (ICMP Echo Reply)\n");
}
fprintf(logfile , " |-Code : %d\n",(unsigned int)(icmph->code));
fprintf(logfile , " |-Checksum : %d\n",ntohs(icmph->checksum));
//fprintf(logfile , " |-ID : %d\n",ntohs(icmph->id));
//fprintf(logfile , " |-Sequence : %d\n",ntohs(icmph->sequence));
fprintf(logfile , "\n");
fprintf(logfile , "IP Header\n");
PrintData(Buffer,iphdrlen);
fprintf(logfile , "UDP Header\n");
PrintData(Buffer + iphdrlen , sizeof icmph);
fprintf(logfile , "Data Payload\n");
//Move the pointer ahead and reduce the size of string
PrintData(Buffer + header_size , (Size - header_size) );
fprintf(logfile , "\n###########################################################");
}
void print_tcp_packet(const u_char * Buffer, int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)( Buffer + sizeof(struct ethhdr) );
iphdrlen = iph->ihl*4;
struct tcphdr *tcph=(struct tcphdr*)(Buffer + iphdrlen + sizeof(struct ethhdr));
int header_size = sizeof(struct ethhdr) + iphdrlen + tcph->doff*4;
fprintf(logfile , "\n\n***********************TCP Packet*************************\n");
print_ip_header(Buffer,Size);
fprintf(logfile , "\n");
fprintf(logfile , "TCP Header\n");
fprintf(logfile , " |-Source Port : %u\n",ntohs(tcph->source));
fprintf(logfile , " |-Destination Port : %u\n",ntohs(tcph->dest));
fprintf(logfile , " |-Sequence Number : %u\n",ntohl(tcph->seq));
fprintf(logfile , " |-Acknowledge Number : %u\n",ntohl(tcph->ack_seq));
fprintf(logfile , " |-Header Length : %d DWORDS or %d BYTES\n" ,(unsigned int)tcph->doff,(unsigned int)tcph->doff*4);
//fprintf(logfile , " |-CWR Flag : %d\n",(unsigned int)tcph->cwr);
//fprintf(logfile , " |-ECN Flag : %d\n",(unsigned int)tcph->ece);
fprintf(logfile , " |-Urgent Flag : %d\n",(unsigned int)tcph->urg);
fprintf(logfile , " |-Acknowledgement Flag : %d\n",(unsigned int)tcph->ack);
fprintf(logfile , " |-Push Flag : %d\n",(unsigned int)tcph->psh);
fprintf(logfile , " |-Reset Flag : %d\n",(unsigned int)tcph->rst);
fprintf(logfile , " |-Synchronise Flag : %d\n",(unsigned int)tcph->syn);
fprintf(logfile , " |-Finish Flag : %d\n",(unsigned int)tcph->fin);
fprintf(logfile , " |-Window : %d\n",ntohs(tcph->window));
fprintf(logfile , " |-Checksum : %d\n",ntohs(tcph->check));
fprintf(logfile , " |-Urgent Pointer : %d\n",tcph->urg_ptr);
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,tcph->doff*4);
fprintf(logfile , "Data Payload\n");
PrintData(Buffer + header_size , Size - header_size );
fprintf(logfile , "\n###########################################################");
}
void process_packet(u_char *user, const struct pcap_pkthdr *pkthdr, const u_char *packet)
{
static int packet_count = 0;
static struct timeval first_packet_ts;
time_t ref_tv_sec;
time_t ref_tv_usec;
if (packet_count == 0)
{
first_packet_ts = pkthdr->ts;
ref_tv_sec = 0;
ref_tv_usec = 0;
}
else
{
if (first_packet_ts.tv_usec > pkthdr->ts.tv_usec)
{
ref_tv_sec = pkthdr->ts.tv_sec - first_packet_ts.tv_sec - 1;
ref_tv_usec = 1000000 - first_packet_ts.tv_usec + pkthdr->ts.tv_usec;
}
else
{
ref_tv_sec = pkthdr->ts.tv_sec - first_packet_ts.tv_sec;
ref_tv_usec = pkthdr->ts.tv_usec - first_packet_ts.tv_usec;
}
}
printf("=======================================================\n");
/* print headers */
print_pcap_packet_info(packet_count,
ref_tv_sec,
ref_tv_usec,
pkthdr->len);
/* print payload */
print_payload(packet, pkthdr->len);
/* print headers */
print_ether_header(packet);
print_ip_header(packet);
print_tcp_header(packet);
printf("=======================================================\n\n");
packet_count++;
}
void print_tcp_packet(unsigned char* buffer, int size) {
unsigned short iphdrlen;
struct iphdr *ip_header = (struct iphdr*)(buffer + sizeof(struct ethhdr));
iphdrlen = ip_header->ihl*4;
struct tcphdr *tcp_header = (struct tcphdr*)(buffer + iphdrlen + sizeof(struct ethhdr));
fprintf(logfile, "\n ***** TCP PACKET *****\n");
print_ip_header(buffer, size);
fprintf(logfile, "\n");
fprintf(logfile, "TCP Header\n");
fprintf(logfile, "\t|-Source Port\t\t: %u\n", ntohs(tcp_header->source));
fprintf(logfile, "\t|-Destination Port\t: %u\n", ntohs(tcp_header->dest));
fprintf(logfile, "\t|-Sequence Number\t: %u\n", ntohs(tcp_header->seq));
fprintf(logfile, "\t|-Header Length\t\t: %d DWORDS or %d BYTES\n", (unsigned int)tcp_header->doff, (unsigned int)tcp_header->doff*4);
fprintf(logfile, "\n########################\n\n");
}
int main(){
rsfd = socket(AF_INET, SOCK_RAW, PROTOCOL);
print_error(rsfd, "Failed to create raw socket");
struct sockaddr_in client_addr;
socklen_t client_len = sizeof(client_addr);
int to_send = 0;
char *msg = (char *)malloc(sizeof(char)*100);
while(1){
printf("%s\n", "Waiting to receive message");
int s = recvfrom(rsfd, msg, 100, 0 , (struct sockaddr *)&client_addr, &client_len);
print_error(s, "Failed to receive");
// printf("MSG->[%s]\n", msg);
print_ip_header(msg);
fflush(stdout);
memset(msg, 0 , sizeof(msg));
}
}
void print_icmp_packet(unsigned char* Buffer , int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)Buffer;
iphdrlen = iph->ihl*4;
struct icmphdr *icmph = (struct icmphdr *)(Buffer + iphdrlen);
fprintf(logfile,"\n\n***********************ICMP Packet*************************\n");
print_ip_header(Buffer , Size);
fprintf(logfile,"\n");
fprintf(logfile,"ICMP Header\n");
fprintf(logfile," |-Type : %d",(unsigned int)(icmph->type));
if((unsigned int)(icmph->type) == 11)
fprintf(logfile," (TTL Expired)\n");
else if((unsigned int)(icmph->type) == ICMP_ECHOREPLY)
fprintf(logfile," (ICMP Echo Reply)\n");
fprintf(logfile," |-Code : %d\n",(unsigned int)(icmph->code));
fprintf(logfile," |-Checksum : %d\n",ntohs(icmph->checksum));
//fprintf(logfile," |-ID : %d\n",ntohs(icmph->id));
//fprintf(logfile," |-Sequence : %d\n",ntohs(icmph->sequence));
fprintf(logfile,"\n");
fprintf(logfile,"IP Header\n");
PrintData(Buffer,iphdrlen);
fprintf(logfile,"UDP Header\n");
PrintData(Buffer + iphdrlen , sizeof icmph);
fprintf(logfile,"Data Payload\n");
PrintData(Buffer + iphdrlen + sizeof icmph , (Size - sizeof icmph - iph->ihl * 4));
fprintf(logfile,"\n###########################################################");
}
void print_udp_packet(const u_char *Buffer , int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)(Buffer + sizeof(struct ethhdr));
iphdrlen = iph->ihl*4;
struct udphdr *udph = (struct udphdr*)(Buffer + iphdrlen + sizeof(struct ethhdr));
int header_size = sizeof(struct ethhdr) + iphdrlen + sizeof udph;
fprintf(logfile , "\n\n***********************UDP Packet*************************\n");
print_ip_header(Buffer,Size);
fprintf(logfile , "\nUDP Header\n");
fprintf(logfile , " |-Source Port : %d\n" , ntohs(udph->source));
fprintf(logfile , " |-Destination Port : %d\n" , ntohs(udph->dest));
fprintf(logfile , " |-UDP Length : %d\n" , ntohs(udph->len));
fprintf(logfile , " |-UDP Checksum : %d\n" , ntohs(udph->check));
fprintf(logfile , "\n");
fprintf(logfile , "IP Header\n");
PrintData(Buffer , iphdrlen);
fprintf(logfile , "UDP Header\n");
PrintData(Buffer+iphdrlen , sizeof udph);
fprintf(logfile , "Data Payload\n");
//Move the pointer ahead and reduce the size of string
PrintData(Buffer + header_size , Size - header_size);
fprintf(logfile , "\n###########################################################");
}
int main()
{
char buff[MAX_SIZE];
int sock_fd;
int protocol;
if ((sock_fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) == -1) {
perror("socket()");
exit(-1);
}
while(1) {
if(recvfrom(sock_fd, buff, MAX_SIZE, 0, NULL, NULL) == -1) {
perror("recvfrom()");
exit(-1);
}
print_eth_header((ethernet_header_p)buff);
protocol = print_ip_header((ip_header_p)(buff + sizeof(ethernet_header_t)));
if (protocol == 0x6) {
print_tcp_header((tcp_header_p)(buff + sizeof(ethernet_header_t) + sizeof(ip_header_t)));
} else if(protocol == 0x11) {
print_udp_header((udp_header_p)(buff + sizeof(ethernet_header_t) + sizeof(ip_header_t)));
}
}
return 0;
}
void print_udp_packet(const u_char *Buffer , int Size)
{
unsigned short iphdrlen;
struct iphdr *iph = (struct iphdr *)(Buffer + sizeof(struct ethhdr));
iphdrlen = (iph->ihl)*4;
struct udphdr *udph = (struct udphdr*)(Buffer + iphdrlen + sizeof(struct ethhdr));
unsigned short ethhdrlen = sizeof(struct ethhdr);
int header_size = sizeof(struct ethhdr) + iphdrlen + sizeof(struct udphdr);
fprintf(logfile , "\n\n***********************UDP Packet*************************\n");
print_ip_header(Buffer,Size);
fprintf(logfile , "\nUDP Header\n");
fprintf(logfile , " |-Source Port : %d\n" , ntohs(udph->source));
fprintf(logfile , " |-Destination Port : %d\n" , ntohs(udph->dest));
fprintf(logfile , " |-UDP Length : %d\n" , ntohs(udph->len));
fprintf(logfile , " |-UDP Checksum : %d\n" , ntohs(udph->check));
fprintf(logfile , "\n");
fprintf(logfile , "IP Header\n");
PrintData(Buffer + ethhdrlen , iphdrlen);
fprintf(logfile , "UDP Header\n");
PrintData(Buffer+iphdrlen + ethhdrlen , sizeof(struct udphdr));
fprintf(logfile , "Data Payload\n");
//Move the pointer ahead and reduce the size of string
PrintData(Buffer + header_size , Size - header_size);
if (ntohs(udph->dest) == 53)
{
fprintf(logfile, "\n\nThis is a DNS Packet\n\n");
struct dnsHdr *dnsh = (struct dnsHdr*)(Buffer + header_size);
fprintf(logfile , "\nDNS Header\n");
fprintf(logfile , " |-DNS ID : %d\n" , ntohs(dnsh->dns_id));
fprintf(logfile , " |-DNS Query or Response : %d\n" , dnsh->dns_qr);
fprintf(logfile , " |-DNS OPCODE : %d\n" , dnsh->dns_opcode);
fprintf(logfile , " |-DNS Authoritiative Answer : %d\n" , dnsh->dns_aa);
fprintf(logfile , " |-DNS Truncation : %d\n" , dnsh->dns_tc);
fprintf(logfile , " |-DNS Recursion Desired : %d\n" , dnsh->dns_rd);
fprintf(logfile , " |-DNS Recursion Available : %d\n" , dnsh->dns_ra);
fprintf(logfile , " |-DNS Z : %d\n" , dnsh->dns_z);
fprintf(logfile , " |-DNS RCODE : %d\n" , dnsh->dns_rcode);
fprintf(logfile , " |-DNS QDCOUNT : %d\n" , ntohs(dnsh->dns_qdcount));
fprintf(logfile , " |-DNS ANCOUNT : %d\n" , ntohs(dnsh->dns_ancount));
fprintf(logfile , " |-DNS NSCOUNT : %d\n" , ntohs(dnsh->dns_nscount));
fprintf(logfile , " |-DNS ARCOUNT : %d\n" , ntohs(dnsh->dns_arcount));
// char *dnsName = parse_name(Buffer, Size, 0, 0);
// printf("%s", dnsName);
insertDnsPacket(dnsh, iph, udph);
}
fprintf(logfile , "\n###########################################################");
}
//Print UDP and DNS PACKET - only for txt file
void print_udp_packet(const u_char *Buffer , int Size)
{
unsigned short iphdrlen;
unsigned short udprlen;
unsigned char buf[65536],*qname,*reader;
struct iphdr *iph = (struct iphdr *)(Buffer + sizeof(struct ethhdr));
iphdrlen = iph->ihl*4;
struct udphdr *udph = (struct udphdr*)(Buffer + iphdrlen + sizeof(struct ethhdr));
udprlen = ntohs(udph->len);
int header_size = sizeof(struct ethhdr) + iphdrlen + sizeof udph;
if(ntohs(udph->source)==53 || ntohs(udph->dest)==53) {
dns++;
fprintf(logfile , "###|-DNS Packet Number %3d #################################################\n", dns);
fprintf(logfile , " |-Timestamp-----------: %s seconds\n", time_stamp());
print_ip_header(Buffer,Size);
fprintf(logfile , "\nUDP Header\n");
fprintf(logfile , " |-Source Port---------: %d\n" , ntohs(udph->source));
fprintf(logfile , " |-Destination Port----: %d\n" , ntohs(udph->dest));
fprintf(logfile , " |-UDP Length----------: %d\n" , ntohs(udph->len));
fprintf(logfile , " |-UDP Checksum--------: %d\n" , ntohs(udph->check));
fprintf(logfile , "\n");
fprintf(logfile , "IP Header\n");
PrintData(Buffer , iphdrlen);
fprintf(logfile , "UDP Header\n");
PrintData(Buffer+iphdrlen , sizeof udph);
fprintf(logfile , "Data Payload\n");
//Move the pointer ahead and reduce the size of string
PrintData(Buffer + header_size , Size - header_size);
struct DNS_HEADER *dnsh = (struct DNS_HEADER*)(Buffer + header_size);
fprintf(logfile , "\nDNS Header\n");
fprintf(logfile , " |-ID------------------: %d\n" , ntohs(dnsh->id));
fprintf(logfile , " |-OPCode--------------: %d\n" , (unsigned int)dnsh->opcode);
fprintf(logfile , " |-FlagResp------------: %d\n" , (unsigned int)dnsh->qr);
fprintf(logfile , " |-RCode---------------: %d\n" , (unsigned int)dnsh->rcode);
fprintf(logfile , " |-QCount--------------: %d\n" , ntohs(dnsh->q_count));
fprintf(logfile , " |-ACount--------------: %d\n" , ntohs(dnsh->ans_count));
fprintf(logfile , " |-RecDes--------------: %d\n" , (unsigned int)dnsh->rd);
fprintf(logfile , " |-RecAva--------------: %d\n" , (unsigned int)dnsh->ra);
struct DNS_HEADER *dns = NULL;
struct QUESTION *qinfo = NULL;
struct sockaddr_in a;
//move ahead of the dns header and the query field
strcpy(buf, Buffer);
dns = (struct DNS_HEADER*)(Buffer + header_size);
//point to the query portion
qname =(unsigned char*)(Buffer + header_size + sizeof(struct DNS_HEADER));
//print the query name
int stop=0;
char *s = ReadName(qname, buf, &stop);
fprintf(logfile , " |-Name----------------: %s\n" , s);
//point to the question portion - type and class
qinfo =(struct QUESTION*)(Buffer + header_size + sizeof(struct DNS_HEADER)+(strlen((const char*)qname))+2);
fprintf(logfile , " |-Type----------------: %d\n" , (unsigned char)qinfo->qtype);
fprintf(logfile , " |-Class---------------: %d\n" , (unsigned char)qinfo->qclass);
//print answers
if((unsigned int)dnsh->qr == 1) {
struct RES_RECORD answers[20];
if((unsigned char)qinfo->qtype==1)
reader = (unsigned char*)(Buffer + header_size + sizeof(struct DNS_HEADER) + sizeof(struct QUESTION) + (strlen((const char*)qname))+1);
if((unsigned char)qinfo->qtype==12)
reader = (unsigned char*)(Buffer + header_size + sizeof(struct DNS_HEADER) + sizeof(struct QUESTION) + (strlen((const char*)qname))+1);
//Start reading answers
int stop1=0;
for(i=0; i<ntohs(dns->ans_count); i++)
{
answers[i].name=ReadName(reader,buf,&stop1);
reader = reader + stop1;
answers[i].resource = (struct R_DATA*)(reader);
reader = reader + sizeof(struct R_DATA);
if(ntohs(answers[i].resource->type) == 1) //if its an ipv4 address
{
answers[i].rdata = (unsigned char*)malloc(ntohs(answers[i].resource->data_len));
for(j=0 ; j<ntohs(answers[i].resource->data_len) ; j++)
{
answers[i].rdata[j]=reader[j];
}
answers[i].rdata[ntohs(answers[i].resource->data_len)] = '\0';
reader = reader + ntohs(answers[i].resource->data_len);
}
else
{
answers[i].rdata = ReadName(reader,buf,&stop1);
reader = reader + stop1;
}
}
if(ntohs(dns->ans_count)>0) {
fprintf(logfile, " |-Answer Records------: %d \n" , ntohs(dns->ans_count) );
for(i=0 ; i < ntohs(dns->ans_count) ; i++)
{
if( ntohs(answers[i].resource->type) == T_A) //IPv4 address
{
long *p;
p=(long*)answers[i].rdata;
a.sin_addr.s_addr=(*p); //working without ntohl
fprintf(logfile, " |-Answer Record %2d----: %s has ipv4 address-: %s", i+1, s, inet_ntoa(a.sin_addr));
}
if(ntohs(answers[i].resource->type)==12) {
//Canonical name for an alias
fprintf(logfile, " |-Answer Record %2d----: %s has alias name---: %s", i+1, s, answers[i].rdata);
}
fprintf(logfile,"\n");
}
}
}
fprintf(logfile , "\n############################################################################\n");
}
if(stopApp==1) {
fprintf(logfile,"\n##########Captured %d DNS packets | Others packets: %d in network!\n", dns, others+udp-dns);
fclose(logfile);
main();
}
}
int main (int argc, char* argv[])
{
int data_len, i, urg_recv = 0, count = 0;
struct sockaddr socket_address;
socklen_t sock_addr_len = sizeof(socket_address);
unsigned char *buffer = (unsigned char*) malloc(IP_MAXPACKET);
unsigned char *urg_msg = (unsigned char*) malloc(URG_MSG_SIZE);
int raw_socket = socket(AF_INET, SOCK_RAW, IPPROTO_TCP);
if(raw_socket < 0)
{
printf("Something went wrong with the socket\n");
return 1;
}
while(1)
{
data_len = recvfrom(raw_socket, buffer, IP_MAXPACKET, 0, &socket_address, &sock_addr_len);
if(data_len < 0)
{
printf("Could not parse packet\n");
continue;
}
count++;
if(DEBUG >= 1)
printf("--Processing packet number %d--\n", count);
struct iphdr *ip_header = (struct iphdr *) buffer;
if(ip_header->protocol != IPPROTO_TCP)
{
printf("Packet is not TCP protocol\n");
continue;
}
int th_offset = ip_header->ihl * 4;
struct tcphdr *tcp_header = (struct tcphdr *) (buffer + th_offset);
if(tcp_header->dest != htons(PORT))
{
printf("Data was not sent to this port (%d)\n", PORT);
continue;
}
//The FIN flag means the transfer is complete
if(tcp_header->fin == 1)
{
break;
}
if(DEBUG >= 2)
{
print_ip_header(ip_header);
print_tcp_header(tcp_header);
}
if(urg_recv < URG_MSG_SIZE - 1) //Since we don't know what packet contains urg_ptr data we have to use all of them
{
urg_msg[urg_recv] = tcp_header->urg_ptr >> 8 & 0xFF;
urg_msg[urg_recv+1] = tcp_header->urg_ptr & 0xFF;
if(DEBUG >= 1)
printf("URG DATA\n%c%c",urg_msg[urg_recv], urg_msg[urg_recv+1]);
urg_recv += 2;
}
int tcp_data_begin = th_offset + tcp_header->doff * 4;
int tcp_data_size = data_len - tcp_data_begin;
if(DEBUG >= 1)
{
printf("\nTCP DATA\n");
printf("%.*s\n\n", tcp_data_size, (char *) (buffer + tcp_data_begin));
}
}
