vendor/Windows/npcap-sdk-1.13/Examples-pcap/readfile_ex/readfile_ex.c

#include <stdio.h>
#include <pcap.h>

#define LINE_LEN 16

#ifdef _WIN32
#include <tchar.h>
BOOL LoadNpcapDlls()
{
	_TCHAR npcap_dir[512];
	UINT len;
	len = GetSystemDirectory(npcap_dir, 480);
	if (!len) {
		fprintf(stderr, "Error in GetSystemDirectory: %x", GetLastError());
		return FALSE;
	}
	_tcscat_s(npcap_dir, 512, _T("\\Npcap"));
	if (SetDllDirectory(npcap_dir) == 0) {
		fprintf(stderr, "Error in SetDllDirectory: %x", GetLastError());
		return FALSE;
	}
	return TRUE;
}
#endif

int main(int argc, char **argv)
{
	pcap_t *fp;
	char errbuf[PCAP_ERRBUF_SIZE];
	struct pcap_pkthdr *header;
	const u_char *pkt_data;
	u_int i=0;
	int res;
	
#ifdef _WIN32
	/* Load Npcap and its functions. */
	if (!LoadNpcapDlls())
	{
		fprintf(stderr, "Couldn't load Npcap\n");
		exit(1);
	}
#endif

	if(argc != 2)
	{	
		printf("usage: %s filename", argv[0]);
		return -1;

	}
	
	/* Open the capture file */
	if ((fp = pcap_open_offline(argv[1],			// name of the device
						 errbuf					// error buffer
						 )) == NULL)
	{
		fprintf(stderr,"\nUnable to open the file %s.\n", argv[1]);
		return -1;
	}
	
	/* Retrieve the packets from the file */
	while((res = pcap_next_ex(fp, &header, &pkt_data)) >= 0)
	{
		/* print pkt timestamp and pkt len */
		printf("%ld:%ld (%ld)\n", header->ts.tv_sec, header->ts.tv_usec, header->len);			
		
		/* Print the packet */
		for (i=1; (i < header->caplen + 1 ) ; i++)
		{
			printf("%.2x ", pkt_data[i-1]);
			if ( (i % LINE_LEN) == 0) printf("\n");
		}
		
		printf("\n\n");		
	}
	
	
	if (res == -1)
	{
		printf("Error reading the packets: %s\n", pcap_geterr(fp));
	}
	
	pcap_close(fp);
	return 0;
}