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| #include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <netinet/if_ether.h>
#include <netinet/tcp.h>
#include <net/if.h>
#include <linux/ip.h>
#include <linux/filter.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <time.h>
int backupInit(FILE **file){
*file = fopen("log","w+");
if(file == NULL){
return -1;
}
return 0;
}
int printLog(char *str,FILE* file){
fprintf(stdout,str);
fprintf(file,str);
}
int getNowtime(FILE* file)
{
static char str[60]={0};
char YMD[15] = {0};
char HMS[10] = {0};
time_t current_time;
struct tm* now_time;
char *cur_time = (char *)malloc(21*sizeof(char));
time(¤t_time);
now_time = localtime(¤t_time);
strftime(YMD, sizeof(YMD), "%F ", now_time);
strftime(HMS, sizeof(HMS), "%T", now_time);
strncat(cur_time, YMD, 11);
strncat(cur_time, HMS, 8);
sprintf(str,"==========\nCurrent time: %s\n==========\n", cur_time);
printLog(str,file);
free(cur_time);
cur_time = NULL;
return 0;
}
int change(size_t num,int key){
return (num >> (key*8))&0x000000ff;
}
int main(int argc, char **argv) {
int sock, n;
FILE* file;
char buffer[2048];
char str[512];
unsigned char *ethhead;
struct iphdr *iphead;
struct tcphdr *tcphead;
struct sock_filter BPF_code[]= {
{ 0x28, 0, 0, 0x0000000c },
{ 0x15, 0, 4, 0x00000800 },
{ 0x20, 0, 0, 0x0000001a },
{ 0x15, 8, 0, 0xc0a89d88 },
{ 0x20, 0, 0, 0x0000001e },
{ 0x15, 6, 7, 0xc0a89d88 },
{ 0x15, 1, 0, 0x00000806 },
{ 0x15, 0, 5, 0x00008035 },
{ 0x20, 0, 0, 0x0000001c },
{ 0x15, 2, 0, 0xc0a89d88 },
{ 0x20, 0, 0, 0x00000026 },
{ 0x15, 0, 1, 0xc0a89d88 },
{ 0x6, 0, 0, 0x00040000 },
{ 0x6, 0, 0, 0x00000000 },
};
struct sock_fprog Filter;
Filter.len = 14;
Filter.filter = BPF_code;
if ((sock=socket(PF_PACKET, SOCK_RAW,htons(ETH_P_IP)))<0){
perror("socket");
exit(1);
}
if(backupInit(&file)<0){
perror("backup");
exit(1);
}
if(setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER,&Filter, sizeof(Filter))<0){
perror("setsockopt");
close(sock);
exit(1);
}
getNowtime(file);
while (1) {
n = recvfrom(sock,buffer,2048,0,NULL,NULL);
sprintf(str,"%d bytes read\n",n);
printLog(str,file);
if (n<42) {
perror("recvfrom():");
printf("Incomplete packet (errno is %d)\n",errno);
close(sock);
exit(0);
}
ethhead = buffer;
sprintf(str,"Source MAC address: "
"%02x:%02x:%02x:%02x:%02x:%02x\n",
ethhead[0],ethhead[1],ethhead[2],
ethhead[3],ethhead[4],ethhead[5]);
printLog(str,file);
sprintf(str,"Destination MAC address: "
"%02x:%02x:%02x:%02x:%02x:%02x\n",
ethhead[6],ethhead[7],ethhead[8],
ethhead[9],ethhead[10],ethhead[11]);
printLog(str,file);
iphead = (struct iphdr*)(buffer+14);
tcphead = (struct tcphdr*)(buffer+14+20);
if (iphead->version > 0) {
sprintf(str,"Source host %d.%d.%d.%d\n",
change(iphead->saddr,0),change(iphead->saddr,1),
change(iphead->saddr,2),change(iphead->saddr,3));
printLog(str,file);
sprintf(str,"Dest host %d.%d.%d.%d\n",
change(iphead->daddr,0),change(iphead->daddr,1),
change(iphead->daddr,2),change(iphead->daddr,3));
printLog(str,file);
sprintf(str,"Source ports:%d\nDest ports:%d\n",
tcphead->source,tcphead->dest);
printLog(str,file);
sprintf(str,"Layer-4 protocol %d\n",iphead->protocol);
printLog(str,file);
}
sprintf(str,"----------\n");
printLog(str,file);
}
}
|
