libpcap을 이용하여 send packet 만드는데요..

libpcap을 이용하여 send packet을 만들려고합니다..
winpcap을 응용하여 리눅스 CentOS5에서 libpcap으로

소스를 건드려가면서 하는중인데요...
일단 ARP를 타겟 IP에 보내서 그 타겟 IP가 맥주소를 response
해주면 성공입니다..

지금까지 짠 소스는 이정도인데.. 소스 정리와 추가할것좀 알려주세요.
주석달아주시면서 간단한 설명도 첨부해주시면 감사하겠습니다..
그리고 ARP말고도 IP,TCP등등의 것들의 소스도 올려주시면 감사하겠습니다.

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define PROMISCUOUS 1
#define NONPROMISCUOUS 0

void main(int argc, char **argv)
{
pcap_t *fp;
char errbuf[PCAP_ERRBUF_SIZE];
u_char packet[100];
char *dev;
int i;

dev = pcap_lookupdev(errbuf);

if( dev == NULL )
{
printf("%s\n", errbuf);
exit(1);
}

if(argc !=2)
{

printf("usage : %s interface (e.g. 'rpcap://eth0')", argv[0]);
return;
}

if ( (fp = pcap_open_live(dev, BUFSIZ, NONPROMISCUOUS, 0, errbuf)) == NULL)
{
printf(stderr, "Unable to open the Adapter.%s is not supported by Libpcap ", argv[1]);
return;
}

/* Supposing to be on ethernet, set mac destination to */
packet[0] = 0xFF;
packet[1] = 0xFF;
packet[2] = 0xFF;
packet[3] = 0xFF;
packet[4] = 0xFF;
packet[5] = 0xFF;

/* set mac source to */
packet[6] = 0x00;
packet[7] = 0x11;
packet[8] = 0x22;
packet[9] = 0x33;
packet[10] = 0x44;
packet[11] = 0x55;

/* ARP */
packet[12] = 0x08;
packet[13] = 0x06;

/* Hardware Type (ethernet) */
packet[14] = 0x00;
packet[15] = 0x01;

/* protocol type(ip) */
packet[16] = 0x08;
packet[17] = 0x00;

/* Hardware Length */
packet[18] = 0x06;

/* Protocol Length */
packet[19] = 0x04;

/* Operation (request :1, reply : 2) */
packet[20] = 0x01;
packet[21] = 0x02;

/* Sender Hardware Address */
packet[22] = 0x00;
packet[23] = 0x0C;
packet[24] = 0x29;
packet[25] = 0x71;
packet[26] = 0x4C;
packet[27] = 0x2D;

/* Sender Protocol Address */
packet[28] = 0xC0;
packet[29] = 0xA8;
packet[30] = 0xF7;
packet[31] = 0x82;

/* Target Hardware Address (Empty) */
packet[32] = 0xFF;
packet[33] = 0xFF;
packet[34] = 0xFF;
packet[35] = 0xFF;
packet[36] = 0xFF;
packet[37] = 0xFF;
/*
packet[32] = 0x00;
packet[33] = 0x0E;
packet[34] = 0xE8;
packet[35] = 0xE8;
packet[36] = 0xEC;
packet[37] = 0x5E;
*/
/* Target Protocol Address */
packet[38] = 0xC0;
packet[39] = 0xA8;
packet[40] = 0x00;
packet[41] = 0x04;

/* file the rest of the packet */
for( i=12 ; i<100 ; i++ )
{
packet[i] = i%256;
}

if (pcap_sendpacket(fp, packet, 100 /* size */ ) != 0 )
{
printf(stderr, "\nError sending the packet: \n", pcap_geterr(fp));
return;
}
return;
}