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httptracker.c
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httptracker.c
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#include "proto_h.h"
#include <pcap.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netpacket/packet.h>
#include <linux/if_ether.h>
#include <stdlib.h>
#include <string.h>
#define OPT_STRING "-m-v-s-d-l-a-h-n:-i:"
#define SNAP_LEN 1518
#define PCAP_FILTER "tcp port 80 || tcp port 8080"
#define PROMISC 1
#define INTF_ALL "any"
struct args{
int debug_mode;
int verbose;
int print_src_ip;
int link_type;
};
void usage();
//void description();
void process_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *packet);
void list_interfaces();
void http_tracker(int debug_mode,int exclude_own,int verbose,int print_src_ip,int excl_loopback,int exit_count,char * intf);
void get_interface_addresses(char *intf,char intf_addresses[][26]);
char* packet_to_a(unsigned char*,int);
float timeval_to_sec(struct timeval);
int main(int argc, char ** argv){
/*s
sdfsssssssssss */
//initialized with default values
int exclude_own = 0;
int verbose = 0;
int print_src_ip = 0;
int debug_mode=0;
int excl_loopback=0;
int help=0;
int list_intf=0;
int exit_count=0;
char *intf=0;
char opt=0;
//get the options provided
opt=getopt(argc,argv,OPT_STRING);
while(opt!=-1){
switch (opt) {
case 'm':
exclude_own=1;
break;
case 'v':
verbose=1;
break;
case 's':
print_src_ip=1;
break;
case 'd':
debug_mode=1;
break;
case 'l':
excl_loopback=1;
break;
case 'h':
help=1;
break;
case 'a':
list_intf=1;
break;
case 'n':
exit_count=optarg;
if(!exit_count)
usage();
else
exit_count=(int)*optarg;
break;
case 'i':
intf=optarg;
if(!intf)
usage();
break;
case '?':
usage();
break;
default:
usage();
break;
}
opt=getopt(argc,argv,OPT_STRING);
}
//check for help flag
if(help) usage();
//if the list interfaces was specified
if(list_intf) list_interfaces();
//start the filtering
http_tracker(debug_mode,exclude_own,verbose,print_src_ip,excl_loopback,exit_count,intf);
return(0);
}
// this function displays the usage of the program
void usage(){
fprintf(stdout,"Usage: ./httptracker -m -v -s -h -a -d -l -n count -i intf_name\n");
fprintf(stdout,"-m - exclude packets from your machine on the interface(s) specified\n");
fprintf(stdout,"-v - verbose output (print all of application layer data)\n");
fprintf(stdout,"-s - print src IP address of packets\n");
fprintf(stdout,"-l - exclude any loopback interface when sniffing on all intefaces\n");
fprintf(stdout,"-h - print this help message and exit\n");
fprintf(stdout,"-a - list all intetrfaces available that this program can capture on and exit(depends on user privileges)\n");
fprintf(stdout,"-d - print debug messages\n");
fprintf(stdout,"-n count - number of packets to capture before quitting (-1 (default) equals infinity)\n");
fprintf(stdout,"-i intf_name - capture HTTP traffic on the intf_name interface\n");
exit(0);
}
//this function returns the time in seconds from
//a struct timeval
float timeval_to_sec(struct timeval time){
return time.tv_sec+(time.tv_usec/1000000);
}
//prints padding spaces
void print_padding_spaces(int max_len,int str_len){
int k=0;
while(k<(max_len-str_len)){
printf(" ");
k++;
}
}
//this function is responsible for makng sense of the capture and
//printing relevant matter to the user
void process_packet(u_char *arguments,const struct pcap_pkthdr *header,const u_char *packet){
u_char *app_layer=0;
uint8_t data_len=0;
struct tcp_hdr *trans_layer=0;
uint8_t trans_layer_length=0;
uint8_t trans_hdr_length=0;
struct ip_hdr *ip_layer=0;
uint8_t ip_layer_length=0;
uint8_t ip_hdr_length=0;
char src_port[6];
char dst_port[6];
memset(src_port,0,6);
memset(dst_port,0,6);
//print the time it was sniffed
//printf("%5.3f",timeval_to_sec(header->ts));
//make sense of the arguments, importantly of the link type packet
//this means an ethernet encapsulation IEEE 802.3
if(((struct args*)arguments)->link_type==DLT_EN10MB){
/*if(((struct args*)arguments)->debug_mode)
printf("Link Type: IEEE 802.3 Ethernet\n");*/
printf("%s ",packet_to_a(((struct ether_hdr *)packet)->ether_src,ETHER_ADDR_LEN));
ip_layer=(struct ip_hdr*)(packet+sizeof(struct ether_hdr));
}
else if(((struct args*)arguments)->link_type==DLT_LINUX_SLL){
/*if(((struct args*)arguments)->debug_mode)
printf("Link Type: Linux CookedUp\n");*/
printf("%s ",packet_to_a(((struct linux_cooked *)packet)->lc_ll_addr,
ntohs(((struct linux_cooked *)packet)->lc_ll_addr_len)));
ip_layer=(struct ip_hdr*)(packet+sizeof(struct linux_cooked));
}
else{
printf("Someother link layer encapsulation\n");
return;
}
ip_layer_length=ntohs(ip_layer->ip_tl);
ip_hdr_length=(uint8_t)(ip_layer->ip_vhl & 0x0F)*4;
//this means we gotta print the src IP
if(((struct args*)arguments)->print_src_ip)
printf("%s",inet_ntoa(ip_layer->ip_src));
//print padding spaces
print_padding_spaces(15,strlen(inet_ntoa(ip_layer->ip_src)));
printf(" ");
trans_layer=(struct tcp_hdr *)((uint8_t *)ip_layer+ip_hdr_length);
trans_hdr_length=(uint8_t)((trans_layer->tcp_hlen_rsvd & 0xF0) >> 4)*4;
trans_layer_length=ip_layer_length-ip_hdr_length;
app_layer=(u_char*)((uint8_t *)trans_layer+trans_hdr_length);
data_len=ip_layer_length-(ip_hdr_length+trans_hdr_length);
sprintf(src_port,"%d",ntohs(trans_layer->tcp_src_port));
printf(" %d",ntohs(trans_layer->tcp_src_port));
print_padding_spaces(5,strlen(src_port));
sprintf(dst_port,"%d",ntohs(trans_layer->tcp_dst_port));
printf(" %d",ntohs(trans_layer->tcp_dst_port));
print_padding_spaces(5,strlen(dst_port));
/*if(((struct args*)arguments)->debug_mode){
printf("IPTotalLength:%d ",ip_layer_length);
printf("IPHeaderLength:%d ",ip_hdr_length);
printf("TCPTotalLength:%d ",trans_layer_length);
printf("TCPHeaderLength:%d ",trans_hdr_length);
printf("DataLength:%d ",data_len);
}*/
char *host_ptr=0;
host_ptr=strstr((char *)app_layer,"Host:");
if(host_ptr){
int i=0;
printf(" ");
while(*(host_ptr+i)!='\n')
printf("%c",*(host_ptr+i++));
}
//printf(" %c",*(app_layer));
printf("\n");
}
//the function that performs the actual capture by setting the device,
//opening the device, applying the filter, and calling the function required
//for each packet
void http_tracker(int debug_mode,int exclude_own, int verbose, int print_src_ip,int excl_loopback,int exit_count,char * intf){
if(debug_mode)
fprintf(stdout,"Options Set:\nInclude own IP address (-m): %d\nVerbose (-v): %d\nPrint Source IP (-s): %d\nInterface (-i): %s\n",
exclude_own,verbose,print_src_ip,intf);
char filter_expression[4096];
struct bpf_program fp; /* compiled filter program (expression) */
memset(filter_expression,0,4096);
char *filter_expression_ptr=filter_expression;
//alter the filter expression
strcpy(filter_expression_ptr,PCAP_FILTER);
filter_expression_ptr+=strlen(PCAP_FILTER);
//make sense of the various options provided
//set the interface we need to sniff on
if(!intf) intf=INTF_ALL;
//if we need to exclude packets from one or more of our interfaces
if(exclude_own){
//find the interfaces and get the IP addresses to ignore
char intf_addresses[5][26];
int i=0;
while(i<5)
memset(intf_addresses[i++],0,26);
get_interface_addresses(intf,intf_addresses);
i=0;
//now the rest of the MAC addresses
while(i<5 && intf_addresses[i][0]!=0){
sprintf(filter_expression_ptr," && ether host! %s",intf_addresses[i]);
filter_expression_ptr+=strlen(" && ether host! ")+strlen(intf_addresses[i]);
i++;
}
}
//we need to exclude loopback addresses
if(excl_loopback){
if(!exclude_own){
char intf_addresses[1][26];
memset(intf_addresses[0],0,26);
get_interface_addresses("lo",intf_addresses);
if(strlen(intf_addresses[0])!=0)
sprintf(filter_expression_ptr," && ether host! %s",intf_addresses[0]);
}
}
if(debug_mode) printf("The Filter Expression is %s\n",filter_expression);
//open the device for sniffing
pcap_t *handle=0;
char errbuf[PCAP_ERRBUF_SIZE];
memset(errbuf,0,PCAP_ERRBUF_SIZE);
handle = pcap_open_live(intf,SNAP_LEN,PROMISC,1000,errbuf);
if(handle==NULL){
fprintf(stderr,"Couldn't open device %s\n",errbuf);
if(debug_mode)
fprintf(stdout,"Couldn't open device %s\n",errbuf);
exit(1);
}
//check for any warning messages in errbuf
if(errbuf[1]!=0)
fprintf(stdout,"WARNING: %s",errbuf);
memset(errbuf,0,PCAP_ERRBUF_SIZE);
bpf_u_int32 netip; //IPv4 address
bpf_u_int32 maskp; //Net mask
//get the IPv4 address and netmask of the device provided
if(pcap_lookupnet(intf,&netip,&maskp,errbuf)==-1){
fprintf(stderr,"Couldn't get netmask for device %s: %s\n", intf, errbuf);
if(debug_mode)
fprintf(stdout,"Couldn't get netmask for device %s: %s\n", intf, errbuf);
exit(1);
}
//compile the filter expression
if (pcap_compile(handle, &fp, filter_expression, 0, maskp) == -1) {
fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_expression, pcap_geterr(handle));
exit(1);
}
//apply the compiled filter
if (pcap_setfilter(handle, &fp) == -1) {
fprintf(stderr, "Couldn't install filter %s: %s\n",filter_expression, pcap_geterr(handle));
exit(1);
}
struct args arguments;
arguments.debug_mode=debug_mode;
arguments.verbose=verbose;
arguments.print_src_ip=print_src_ip;
arguments.link_type=pcap_datalink(handle);
//set the callback function
if(exit_count)
pcap_loop(handle,exit_count,process_packet,(u_char*)&arguments);
else
pcap_loop(handle,-1,process_packet,(u_char*)&arguments);
//closing cleanup
pcap_freecode(&fp);
pcap_close(handle);
}
//this function gets the addresses of the interface provided
void get_interface_addresses(char * intf,char intf_addresses[][26]){
//this means we need to get all the possible addresses possible
pcap_if_t *alldevs;
char errbuf[PCAP_ERRBUF_SIZE];
if(pcap_findalldevs(&alldevs,errbuf)==-1){
fprintf(stdout,"Unable to look up interfaces: %s",errbuf);
exit(1);
}
int i=0;
pcap_if_t *temp_dev=0;
for(temp_dev=alldevs;temp_dev!=NULL;){
if(strcmp(intf,INTF_ALL)){
if(strcmp(intf,temp_dev->name)){
temp_dev=temp_dev->next;
continue;
}
}
if(temp_dev->addresses){
pcap_addr_t *temp_pcap_addr=temp_dev->addresses;
//get all possible physical addresses for this device
while(temp_pcap_addr){
if(temp_pcap_addr->addr && temp_pcap_addr->addr->sa_family==AF_PACKET){
strcpy(intf_addresses[i++],packet_to_a(((struct sockaddr_ll *)temp_pcap_addr->addr)->sll_addr,
((struct sockaddr_ll *)temp_pcap_addr->addr)->sll_halen));
}
temp_pcap_addr=temp_pcap_addr->next;
}
}
temp_dev=temp_dev->next;
}
pcap_freealldevs(alldevs);
}
//this function converts a given sa_data member to
//readable MAC address format
char* packet_to_a(unsigned char * sa_data, int length){
static char mac_address[25]; //xx:xx:xx:xx:xx:xx/0
memset(mac_address,0,25);
int i=0;
int j=0;
while(i<length){
sprintf(mac_address+(j++),"%x",((uint8_t)sa_data[i] & 0xF0) >>4);
sprintf(mac_address+(j++),"%x",((uint8_t)sa_data[i]) & 0x0F);
if(i!=length-1)
sprintf(mac_address+(j++),":");
i++;
}
return mac_address;
}
//this function lists all the interfaces that this program can capture
//on (depends in privileges)
void list_interfaces(){
pcap_if_t *alldevs;
char errbuf[PCAP_ERRBUF_SIZE];
if(pcap_findalldevs(&alldevs,errbuf)==-1){
fprintf(stdout,"Unable to look up interfaces: %s",errbuf);
exit(1);
}
//print the details for each interface/device
pcap_if_t *temp_dev=0;
for(temp_dev=alldevs;temp_dev!=NULL;temp_dev=temp_dev->next){
printf("Name: %s",temp_dev->name);
if(temp_dev->description)
printf("\n\tDescription: %s",temp_dev->description);
if(temp_dev->addresses){
pcap_addr_t *temp_pcap_addr=temp_dev->addresses;
while(temp_pcap_addr){
if(temp_pcap_addr->addr){
int address_family=temp_pcap_addr->addr->sa_family;
if(address_family==AF_INET){ //IPv4 address family
printf("\n\tAddress Family: IPv4\n");
printf("\tIPv4 Address: %s",inet_ntoa(((struct sockaddr_in*)temp_pcap_addr->addr)->sin_addr));
}
else if(address_family==AF_PACKET){
printf("\n\tAddress Family: Raw Packet (AF_PACKET)\n");
printf("\tInterface Index: %d",((struct sockaddr_ll *)temp_pcap_addr->addr)->sll_ifindex);
printf("\tMAC Address: %s",
packet_to_a(((struct sockaddr_ll *)temp_pcap_addr->addr)->sll_addr,
((struct sockaddr_ll *)temp_pcap_addr->addr)->sll_halen));
}
}
if(temp_pcap_addr->netmask){
int address_family=temp_pcap_addr->netmask->sa_family;
if(address_family==AF_INET) //IPv4 address family
printf("\tIPv4 Netmask: %s",inet_ntoa(((struct sockaddr_in*)temp_pcap_addr->netmask)->sin_addr));
}
if(temp_pcap_addr->broadaddr){
int address_family=temp_pcap_addr->broadaddr->sa_family;
if(address_family==AF_INET)
printf("\tBroadcast Address: %s",inet_ntoa(((struct sockaddr_in*)temp_pcap_addr->broadaddr)->sin_addr));
else if(address_family==AF_PACKET)
printf("\tBroadcast Address: %s",packet_to_a(((struct sockaddr_ll *)temp_pcap_addr->broadaddr)->sll_addr,
((struct sockaddr_ll *)temp_pcap_addr->broadaddr)->sll_halen));
}
if(temp_pcap_addr->dstaddr){
int address_family=temp_pcap_addr->dstaddr->sa_family;
if(address_family==AF_INET)
printf("\tDestination Address: %s",inet_ntoa(((struct sockaddr_in*)temp_pcap_addr->dstaddr)->sin_addr));
else if(address_family==AF_PACKET)
printf("\tDestination Address: %s", packet_to_a(((struct sockaddr_ll*)temp_pcap_addr->dstaddr)->sll_addr,
((struct sockaddr_ll*)temp_pcap_addr->dstaddr)->sll_halen));
}
temp_pcap_addr=temp_pcap_addr->next;
}
}
if(temp_dev->flags==PCAP_IF_LOOPBACK)
printf("\n\tLoopback Interface");
printf("\n");
}
pcap_freealldevs(temp_dev);
exit(1);
}