#include <winsock.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void error(const char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
   WSADATA wsda;
   SOCKET s;
   SOCKADDR_IN addr, remote_addr;
   u_short iPort = 12134;
   int i, ret, iRemoteAddrLen;
   char hex[16] = "123456789ABCDEF";
   char szMessage[512], szMessageString[512*3];

   WSAStartup(MAKEWORD(2,2), &wsda);
    s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
   //s = socket(AF_INET, SOCK_RAW, IPPROTO_UDP);
   
   if(s == SOCKET_ERROR) 
   {
      printf("Error\nCall to socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   addr.sin_family = AF_INET; 
   addr.sin_port = htons(iPort);
   addr.sin_addr.s_addr = INADDR_ANY;

   if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) == SOCKET_ERROR)
   {
      printf("Error\nCall to bind(s, (struct sockaddr *) &addr, sizeof(addr)); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   printf("Waiting for packets (Press Ctrl-C to exit)...\n");
   while(1)
   {
	   iRemoteAddrLen = sizeof(remote_addr);
	   ret = recvfrom(s, szMessage, sizeof(szMessage), 0, (struct sockaddr *) &remote_addr, &iRemoteAddrLen);

	   if(ret == SOCKET_ERROR)
	   {
		  printf("Error\nCall to recvfrom(s, szMessage, sizeof(szMessage), 0, (struct sockaddr *) &remote_addr, &iRemoteAddrLen); failed with:\n%d\n", WSAGetLastError());
		  exit(1);
	   }

	   for(i=0; i<ret; i++)
	   {
		   szMessageString[i*3+0] = hex[szMessage[i]>>4];
		   szMessageString[i*3+1] = hex[szMessage[i]&0xF];
		   szMessageString[i*3+2] = ' ';
	   }
	   szMessageString[i*3-1] = 0;

	  printf("Received %d bytes from %s\n", ret, inet_ntoa(remote_addr.sin_addr));
   }

   closesocket(s);
   WSACleanup();

   return 0;

  }

#define HAVE_REMOTE
#include "pcap.h"
#include "remote-ext.h"

/* 4 bytes IP address */
typedef struct ip_address{
	u_char byte1;
	u_char byte2;
	u_char byte3;
	u_char byte4;
}ip_address;

/* IPv4 header */
typedef struct ip_header{
	u_char	ver_ihl;		// Version (4 bits) + Internet header length (4 bits)
	u_char	tos;			// Type of service 
	u_short tlen;			// Total length 
	u_short identification; // Identification
	u_short flags_fo;		// Flags (3 bits) + Fragment offset (13 bits)
	u_char	ttl;			// Time to live
	u_char	proto;			// Protocol
	u_short crc;			// Header checksum
	ip_address	saddr;		// Source address
	ip_address	daddr;		// Destination address
	u_int	op_pad;			// Option + Padding
}ip_header;

/* UDP header*/
typedef struct udp_header{
	u_short sport;			// Source port
	u_short dport;			// Destination port
	u_short len;			// Datagram length
	u_short crc;			// Checksum
}udp_header;

/* prototype of the packet handler */
void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data);


int main()
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
char errbuf[PCAP_ERRBUF_SIZE];
char source[10] = "rpcap://";
u_int netmask;
char packet_filter[] = "ip and udp";
struct bpf_program fcode;

	/* Retrieve the device list */
	if (pcap_findalldevs_ex(source, 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 WinPcap is installed.\n");
		return -1;
	}
	
	printf("Enter the interface number (1-%d):",i);
	scanf("%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 adapter */
	if ( (adhandle= pcap_open(d->name,	// name of the device
							 65536,		// portion of the packet to capture. 
										// 65536 grants that the whole packet will be captured on all the MACs.
							 1,			// promiscuous mode
							 1000,		// read timeout
							 NULL,		// remote authentication
							 errbuf		// error buffer
							 ) ) == NULL)
	{
		fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n");
		/* Free the device list */
		pcap_freealldevs(alldevs);
		return -1;
	}
	
	/* Check the link layer. We support only Ethernet for simplicity. */
	if(pcap_datalink(adhandle) != DLT_EN10MB)
	{
		fprintf(stderr,"\nThis program works only on Ethernet networks.\n");
		/* Free the device list */
		pcap_freealldevs(alldevs);
		return -1;
	}
	
	if(d->addresses != NULL)
		/* Retrieve the mask of the first address of the interface */
		netmask=((struct sockaddr_in *)(d->addresses->netmask))->sin_addr.S_un.S_addr;
	else
		/* If the interface is without addresses we suppose to be in a C class network */
		netmask=0xffffff; 


	//compile the filter
	if (pcap_compile(adhandle, &fcode, packet_filter, 1, netmask) <0 )
	{
		fprintf(stderr,"\nUnable to compile the packet filter. Check the syntax.\n");
		/* Free the device list */
		pcap_freealldevs(alldevs);
		return -1;
	}
	
	//set the filter
	if (pcap_setfilter(adhandle, &fcode)<0)
	{
		fprintf(stderr,"\nError setting the filter.\n");
		/* 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);
	
	/* start the capture */
	pcap_loop(adhandle, 0, packet_handler, NULL);
	
	return 0;
}

/* Callback function invoked by libpcap for every incoming packet */
void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data)
{
	struct tm ltime;
	char timestr[16];
	ip_header *ih;
	udp_header *uh;
	u_int ip_len;
	u_short sport,dport;
	time_t local_tv_sec;

	/*
	 * Unused variable
	 */
	(VOID)(param);

	/* convert the timestamp to readable format */
	local_tv_sec = header->ts.tv_sec;
	//localtime(&ltime, &local_tv_sec);
	strftime( timestr, sizeof timestr, "%H:%M:%S", &ltime);

	/* print timestamp and length of the packet */
	printf("%s.%.6d len:%d ", timestr, header->ts.tv_usec, header->len);

	/* retireve the position of the ip header */
	ih = (ip_header *) (pkt_data +
		14); //length of ethernet header

	/* retireve the position of the udp header */
	ip_len = (ih->ver_ihl & 0xf) * 4;
	uh = (udp_header *) ((u_char*)ih + ip_len);

	/* convert from network byte order to host byte order */
	sport = ntohs( uh->sport );
	dport = ntohs( uh->dport );

	/* print ip addresses and udp ports */
	printf("%d.%d.%d.%d.%d -> %d.%d.%d.%d.%d\n",
		ih->saddr.byte1,
		ih->saddr.byte2,
		ih->saddr.byte3,
		ih->saddr.byte4,
		sport,
		ih->daddr.byte1,
		ih->daddr.byte2,
		ih->daddr.byte3,
		ih->daddr.byte4,
		dport);
}