Analyze packets (Microsoft Visual Studio 2010)
//Fenxi1.cpp: Defines the entry point for the console application.
//
The code is as follows:
#include "stdafx.h"
#include "pcap.h"
#include "bittypes.h"
#pragma comment(lib,"ws2_32.lib")
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) + 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 (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; // UDP Datagram length
u_short crc; //Checksum
}udp_header;
/* Callback function prototype */
void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data);
int _tmain(int argc, _TCHAR* argv[])
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
char errbuf[PCAP_ERRBUF_SIZE];
u_int netmask;
char packet_filter[] = "ip and udp";
struct bpf_program fcode;
/* Get device list */
if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
{
fprintf(stderr,"Error in pcap_findalldevs: %s\n", errbuf);
exit(1);
}
/* Print 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");
/* Release Device List */
pcap_freealldevs(alldevs);
return -1;
}
/* Jump to selected device */
for(d=alldevs, i=0; i
< inum-1 ;d=d->next, i++);
/* Open adapter */
if ( (adhandle= pcap_open(d->name, //device name
65536, //Part of packet to capture
// 65535 Guaranteed to capture the full contents of every packet on different data link layers
PCAP_OPENFLAG_PROMISCUOUS, //promiscuous mode
1000, //read timeout
NULL, //remote machine validation
errbuf //error buffer pool
) ) == NULL)
{
fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n");
/* Release Device List */
pcap_freealldevs(alldevs);
return -1;
}
/* Check the data link layer, for simplicity we will only consider Ethernet */
if(pcap_datalink(adhandle) != DLT_EN10MB)
{
fprintf(stderr,"\nThis program works only on Ethernet networks.\ n");
/* Release Device List */
pcap_freealldevs(alldevs);
return -1;
}
if(d->addresses != NULL)
/* Get mask for first address of interface */
netmask=((struct sockaddr_in *)(d->addresses->netmask))->sin_addr.S_un.S_addr;
else
/* If the interface does not have an address, then we assume a mask of class C */
netmask=0xffffff;
//compile filter
if (pcap_compile(adhandle, &fcode, packet_filter, 1, netmask) ts.tv_sec;
ltime=localtime(&local_tv_sec);
strftime( timestr, sizeof timestr, "%H:%M:%S", ltime);
/* Print packet timestamp and length */
printf("%s.%. 6d len:%d ", timestr, header->ts.tv_usec, header->len);
/* Get IP packet header location */
ih = (ip_header *) (pkt_data +
14); //Ethernet header length
/* Get UDP header location */
ip_len = (ih->ver_ihl & 0xf) * 4;
uh = (udp_header *) ((u_char*)ih + ip_len);
/* Convert network byte sequence to host byte sequence */
sport = ntohs( uh->sport );
dport = ntohs( uh->dport );
/* Print IP address and UDP port */
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);
}
Item-->** Attributes (alt+F7)
Configuration Properties-->C/C++--> General--> Attach Include Directory-->(Add the file path (Include) where the header file is located to the Attach Directory C:\WpdPack\Include)
Item-->** Attributes (alt+F7)
Configuration Properties--> Linker--> General--> Add-on Library Directory-->(add Packet.lib;wpcap.lib directory (Lib) to Add-on Library Directory C:\WpdPack\Lib)
Item-->** Attributes (alt+F7)
Configuration Properties--> Linkers--> Input--> Additional Dependency--> Supplement ";Packet.lib;wpcap.lib"
Item-->** Attributes (alt+F7)
Configuration Properties-->C/C++-> Preprocessor--> Preprocessor Definition--> Supplement ";HAVE_REMOTE"
Add the head as follows
#include "pcap.h"
#include "bittypes.h"
#pragma comment(lib,"ws2_32.lib")
Below is the result chart obtained:
