스마트 컨트롤러

20150722

2015 스마트 콘트롤러/업무일지 2015. 7. 23. 00:54

==========================================================================================

NETWORK

==========================================================================================

=TCP

http://www.ktword.co.kr/abbr_view.php?nav=&m_temp1=2437&id=1103

. CODE BITS
URG (1 bit) – URGENT POINTER 필드가 유효
ACK (1 bit) – ACKNOWLEDGMENT필드를 유효
PSH (1 bit) – 세그먼트 PUSH를 요청
RST (1 bit) – 즉시 연결을 끊음(비정상적인 종료)
SYN (1 bit) – sequence numbers 동기화
FIN (1 bit) – 정상적인 종료

=print_Ip()삭제

=SYN / ACK출력

=윈도우 <-> 리눅스 => 계속 패킷 생성

==> 채팅PORT만 보이도록 수정

<PACKET.C>

#include <stdio.h>
#include <netinet/in.h>
#include <pcap/pcap.h>
#include <net/ethernet.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>

#define PORT 7777

int main(void)
{
  char*           cpNICName;
  char           caErrMSG[PCAP_ERRBUF_SIZE];
  int           iCnt;
  unsigned char const *   ucpData;
  pcap_t*         stpDS;
  struct pcap_pkthdr     stInfo;
  struct tcphdr *     stTcp;
  struct ip *        stpIp;

  cpNICName = pcap_lookupdev(caErrMSG);

  if(0 == cpNICName)
  {
    printf("ERRMSG  : [%s]\n",caErrMSG);
    return 100;
  }

  stpDS = pcap_open_live(cpNICName, ETH_DATA_LEN, 1, 0, caErrMSG);

  printf("Packet Monitoring Start....\n");
  getchar();

  while(1)
  {
    ucpData = pcap_next(stpDS, &stInfo);

    if(ETH_P_IP != ntohs(*(unsigned short*)(ucpData+12))) // 2byte 주소
    {
      continue;
    }

    if(IPPROTO_TCP != *(ucpData+23))
    {
      continue;
    }


    stpIp = (struct ip *) (ucpData + sizeof(struct ether_header));
    stTcp = (struct tcphdr *)(ucpData + sizeof(struct ether_header)
        + ((*(ucpData+ sizeof(struct ether_header)) & 0x0F) * 4));

    if(PORT != ntohs(stTcp -> source))
    {
      if(PORT != ntohs(stTcp -> dest))
      {
        continue;
      }
    }
    printf("=============================================\n");
    printf("[%s:%d] ---> ",
        inet_ntoa(stpIp -> ip_src)
        , ntohs(stTcp -> source)
        );

    printf("[%s:%d]\n",
        inet_ntoa(stpIp -> ip_dst)
        , ntohs(stTcp -> dest)
        );

    printf("SYN[%d] ACK[%d] Seq[%010u] Ack[%010u]\n"
        , stTcp -> syn
        , stTcp -> ack
        , ntohl(stTcp -> seq)
        , ntohl(stTcp -> ack_seq)
        );
  }

  pcap_close(stpDS);

  return 0;
}