basic_dump_ex.c

#include "pcap.h"
#include <time.h>


int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
int res;
char errbuf[PCAP_ERRBUF_SIZE];
struct tm ltime;
char timestr[16];
struct pcap_pkthdr *header;
const u_char *pkt_data;
time_t local_tv_sec;
	
    
	/* Retrieve the device list on the local machine */
	if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
	{
		fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
		exit(1);
	}
    
    /* Print the list */
    for(d=alldevs; d; d=d->next)
    {
        printf("%d. %s", ++i, d->name);
        if (d->description)
            printf(" (%s)\n", d->description);
        else
            printf(" (No description available)\n");
    }
	
    if(i==0)
    {
        printf("\nNo interfaces found! Make sure Npcap is installed.\n");
        return -1;
    }
    
    printf("Enter the interface number (1-%d):",i);
    scanf_s("%d", &inum);
    
    if(inum < 1 || inum > i)
    {
        printf("\nInterface number out of range.\n");
        /* Free the device list */
        pcap_freealldevs(alldevs);
        return -1;
    }
	
    /* Jump to the selected adapter */
    for(d=alldevs, i=0; i< inum-1 ;d=d->next, i++);
    
	/* Open the device */
	if ( (adhandle= pcap_open(d->name,			// name of the device
							  65536,			// portion of the packet to capture. 
												// 65536 guarantees that the whole packet will be captured on all the link layers
							  PCAP_OPENFLAG_PROMISCUOUS, 	// promiscuous mode
							  1000,				// read timeout
							  NULL,				// authentication on the remote machine
							  errbuf			// error buffer
							  ) ) == NULL)
	{
		fprintf(stderr,"\nUnable to open the adapter. %s is not supported by Npcap\n", d->name);
		/* Free the device list */
		pcap_freealldevs(alldevs);
		return -1;
	}
    
    printf("\nlistening on %s...\n", d->description);
	
    /* At this point, we don't need any more the device list. Free it */
    pcap_freealldevs(alldevs);
	
	/* Retrieve the packets */
	while((res = pcap_next_ex( adhandle, &header, &pkt_data)) >= 0){
		
		if(res == 0)
			/* Timeout elapsed */
			continue;
		
		/* convert the timestamp to readable format */
		local_tv_sec = header->ts.tv_sec;
		localtime_s(&ltime, &local_tv_sec);
		strftime( timestr, sizeof timestr, "%H:%M:%S", &ltime);
		
		printf("%s,%.6d len:%d\n", timestr, header->ts.tv_usec, header->len);
	}
	
	if(res == -1){
		printf("Error reading the packets: %s\n", pcap_geterr(adhandle));
		return -1;
	}
	
    return 0;
}