20160421_장진웅_업무일지_공장내Network_일대일통신6_멀티채팅2, 패킷보기

오전 수업내용

tcp.h

#ifndef __TCP_H__ 
#define __TCP_H__

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <sys/stat.h>
#include <sys/signal.h>
#include <stdlib.h>
#include <sys/time.h>

#define BSIZE 250
#define IP_SERVER "192.168.1.60"
#define PORT 10000
#define MAXUSER 3


#endif //__TCP_H__

server.c

#include "tcp.h"

int iCSock[MAXUSER];
int iSSock;
int	iUser;

/*
void sRead(int iNum)
{
	char caBuff[BSIZE];
	int iRet;

	iRet=read(iCSock , caBuff, BSIZE);
	caBuff[iRet-1]=0;

	printf("\n Incomming Message: [%s]\n", caBuff);

	printf("input Message: ");
	fflush(stdout);
}
*/




void End(int iNum)
{
	int iCnt;
	close(iSSock);

	for(iCnt=0; iCnt<iUser; ++iCnt)
	{
		write(iCSock[iCnt],"Server is closed", strlen("Server is closed"));
		close(iCSock[iCnt]);
		printf("Die [%d]persons \n", iCnt+1);
	}
	
	exit (0);
}	


int main(int iArg, char *cpAcmd[])
{
	int iRet;
	int iLen;
	int iTSock;
	int iCnt;
	int iCnt2;

	char caBuff[BSIZE];

	int iMaxFD;
	fd_set stRFd;

	short sPort;

	struct sockaddr_in stServer;
	struct sockaddr_in stClient;


	if(iArg==1)
	{
		sPort=PORT;
	}
	else
	{
		sPort=atoi(cpAcmd[1]);
	}



	iSSock=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

	if(iSSock<0)
	{
		printf("can not make a socket \n");
		perror("iSSock");
		return 0;
	}

	iLen= sizeof(stClient);
	bzero(&stServer, iLen);


	stServer.sin_family = AF_INET;
	stServer.sin_addr.s_addr = INADDR_ANY;
	//stServer.sin_port = htons(PORT);

	stServer.sin_port = htons(sPort);


	iRet=bind(iSSock, (struct sockaddr *)&stServer, iLen);

	if(iRet==-1)
	{
		printf("binding error \n");
		perror("bind");
		close(iSSock);
		return 0;
	}

	iRet=listen(iSSock, 5);

	if(iRet==-1)
	{
		printf("listen error \n");
		perror("listen");
		close(iSSock);
		return 0;
	}


	printf("server is running ...[%d] \n", sPort);

	signal(SIGINT, End );


	iUser=0;
	iMaxFD=iSSock;
	while(1)
	{
		printf("input Message: ");
		fflush(stdout);

		FD_ZERO(&stRFd);
		FD_SET(0,&stRFd);
		
		for(iCnt=0;iCnt<iUser;++iCnt)
		{
			FD_SET(iCSock[iCnt], &stRFd);
		}
		
		FD_SET(iSSock, &stRFd);

		select(iMaxFD+1, &stRFd, NULL, NULL, NULL);

		if(FD_ISSET(iSSock, &stRFd)!=0)
		{

			iTSock=accept(iSSock, (struct sockaddr *)&stClient, &iLen);

			if(iTSock==-1)
			{
				printf("accept error \n");
				perror("accept");
				continue;
			}

			if(iUser>=MAXUSER)
			{
				close(iTSock);
				printf("Maxuser is over the number \n");
				continue;
			}

			if(iMaxFD<iTSock)
			{
				iMaxFD=iTSock;
			}

			iCSock[iUser]=iTSock;
			++iUser;

		}


		if(FD_ISSET(0, &stRFd)!=0)
		{
			iRet=read(0, caBuff, BSIZE);

			for(iCnt=0; iCnt<iUser; ++iCnt)
			{
				write(iCSock[iCnt], caBuff, iRet);
			}
		}

		for(iCnt=0; iCnt<iUser; ++iCnt)
		{
			if(FD_ISSET(iCSock[iCnt], &stRFd)!=0)
			{
				iRet=read(iCSock[iCnt], caBuff, BSIZE);

				if(iRet==0)
				{
					printf("client is disconnected [%d] \n",iCnt);

					if(iMaxFD==iCSock[iCnt])
					{
						for(iCnt2=0,iMaxFD=iCSock[0];iCnt2<iUser;++iCnt2) //³»²¨´Â iCnt, ¾Æ¶÷¾¾´Â iUser
						{
							
							if(iCnt==iCnt2)
							{
								continue;
							}

							if(iMaxFD<iCSock[iCnt2])
							{
								iMaxFD=iCSock[iCnt2];
							}

						}

					}

					close(iCSock[iCnt]); //¼ÒÄÏÀ» ´Ý¾ÆÁÖ´Â ¿ªÇÒÀ» ÇÑ´Ù.
					--iUser;
					iCSock[iCnt]=iCSock[iUser]; //Á¦ÀÏ µÚ¿¡ ÀÖ´Â À¯Àú¸¦ ³ª°£ À¯ÀúÀÇ ÀÚ¸®¿¡ ¹èÄ¡ÇÑ´Ù.
					continue;
				}

				
				caBuff[iRet-1]=0;
				
				for(iCnt2=0; iCnt2<iUser; ++iCnt2)
				{
									
					if(iCnt==iCnt2)
					{
						continue;
					}

					write(iCSock[iCnt2], caBuff, iRet); //¸ðµç »ç¶÷¿¡°Ô ¸Þ½ÃÁö¸¦  º¸³½´Ù.(³ª¸¦ Æ÷ÇÔ)

					

				}


				printf("\n [client: %s] \n", caBuff);
			} 
		}
	}

	return 0;
}

client.c

#include "tcp.h"



int iCSock;


void End(int iNum)
{
	close(iCSock);
	exit(0);
}




void sRead(int iNum)
{
     char caBuff[BSIZE];
     int iRet;

     iRet=read(iCSock , caBuff, BSIZE);
     caBuff[iRet-1]=0;

     printf("\n Incomming Message: [%s]\n", caBuff);

     printf("input Message: ");
     fflush(stdout);
}






int main(int iArg, char *cpAcmd[])
{
	int iRet;
	int iLen;
	
	fd_set stRFd;

	char caBuff[BSIZE];

	short sPort;
	struct sockaddr_in stServer;


	if(iArg==1)
    {
        sPort=PORT;
    }
    else
    {
        sPort=atoi(cpAcmd[1]);
    }



	

	iCSock=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if(iCSock<0)
    {
   		printf("can not make a socket \n");
		perror("iCSock");
	    return 0;
    }
	iLen=sizeof(stServer);
	bzero(&stServer, iLen);
	stServer.sin_family = AF_INET;
    stServer.sin_addr.s_addr =inet_addr(IP_SERVER);
    //stServer.sin_port = htons(PORT);
    stServer.sin_port = htons(PORT);


	iRet=connect(iCSock, (struct sockaddr *)&stServer, iLen);
	if(iRet==-1)
	{
		printf("connect error \n");
		perror("connect");
		close(iRet);
		return 0;
	}
	
	printf("server is running ... \n");
	
	signal(SIGINT, End);

	while(1)
	{
	printf("input Message: ");
	
	fflush(stdout);
	
	FD_ZERO(&stRFd);
	FD_SET(0,&stRFd);//Å°º¸µå¿¡¼­ ¹ÞÀº °ªÀ» ±¸Á¶Ã¼¿¡ ÀúÀåÇÑ´Ù.
	FD_SET(iCSock, &stRFd);//³×Æ®¿öÅ©¿¡¼­ ¹ÞÀº °ªÀ» ÀúÀåÇÑ´Ù.

	select(iCSock+1, &stRFd, NULL, NULL, NULL);

	if(FD_ISSET(0, &stRFd)!=0)
	{
   		 iRet=read(0, caBuff, BSIZE);
   		 write(iCSock, caBuff, iRet);
	}

	if(FD_ISSET(iCSock, &stRFd)!=0)
	{
  		iRet=read(iCSock, caBuff, BSIZE);
        
		if(iRet==0)
		{
			printf("server is disconnected \n");
			End(0);
			return 0;
		}
		
		
		
		
		
		caBuff[iRet-1]=0;
        printf("\n [server: %s] \n", caBuff);
	}


	}

	close(iCSock);

	return 0;
}

<출력결과>

오후 수업내용(패킷을 볼 수 있는 것에 대해서 공부를 한다. 도덕심을 키워서 좋은 쪽으로만 사용하도록 하자.)

Network Protocol Analyzer

<참고 자료 주소>

http://www.joinc.co.kr/w/Site/Network_Programing/AdvancedComm/pcap_intro

sudo apt-get install libpcap-dev

ll pcap *

cd /usr/include/net -> vi ethernet.h

소스

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

 int main(void)
 {
     char * cpNicname; //Network interface card name
     char errbuf[PCAP_ERRBUF_SIZE]; //man pcap_lookupdev에서 가지고 온다.
     char *pcap_lookupdev(char *errbuf);

     cpNicname=pcap_lookupdev(errbuf);

     printf("Nicname: [%s] \n", cpNicname);

     return 0;
 }

<출력결과>

 gcc -o main main.c -lpcap

헥사뷰로 보기

<소스>

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

void Hexaview(const unsigned char *ucpData, unsigned int uiLen)
{
    unsigned int uiCnt;
    unsigned int ui16Cnt;

    printf("===================================== \n");
    printf("============ Hexa Viewer ============ \n");

    uiCnt = 0;
    while(160 > uiCnt)
    {
        printf("%p ", uiCnt);

        ui16Cnt = 0;
        while(16 > ui16Cnt)
        {
            printf("%02X ", *ucpData);
            ui16Cnt = ui16Cnt + 1;
            ucpData = ucpData + 1;
        }
        printf("\n");
        printf("%p \n", uiCnt);

        uiCnt = uiCnt + 16;
    }
}


int main(void)
{
    char * cpNicname; //Network interface card name
    char errbuf[PCAP_ERRBUF_SIZE]; //man pcap_lookupdev에서 가지고 온다.
    char *pcap_lookupdev(char *errbuf);
    const unsigned char * ucpData;

    struct pcap_pkthdr stpInfo;

    pcap_t * stpHandle;
    cpNicname=pcap_lookupdev(errbuf);

    if(0==cpNicname)
    {
        perror(errbuf);
        return 0;
    }

    printf("Nicname: [%s] \n", cpNicname);

    stpHandle=pcap_open_live(cpNicname, 1500, 1, 0, errbuf);
    //pcap_t stphandle_open_live(cpNicname, 1500(ethernet), 1(1을해야 promis

    if(stpHandle==0)
    {
        perror(errbuf);
        return 0;
    }
    ucpData=pcap_next(stpHandle, &stpInfo);

    Hexaview(ucpData, 0);

    pcap_close(stpHandle);

    return 0;
}

<출력결과>

<소스>

#include <stdio.h>
#include <pcap.h>
#include <errno.h>
#include <net/ethernet.h>

void Hexaview(const unsigned char *ucpData, unsigned int uiLen)
{
	unsigned int uiCnt;
	unsigned int ui16Cnt;

	printf("===================================== \n");
	printf("============ Hexa Viewer ============ \n");

	uiCnt = 0;
	while(160 > uiCnt)
	{
		printf("%p ", uiCnt);

		ui16Cnt = 0;
		while(16 > ui16Cnt)
		{
			printf("%02X ", *ucpData);
			ui16Cnt = ui16Cnt + 1;
			ucpData = ucpData + 1;
		}
		printf("\n");

		printf("%p \n", uiCnt);


		uiCnt = uiCnt + 16;
	}
}


int main(void)
{
	char * cpNicname; //Network interface card name		
	char errbuf[PCAP_ERRBUF_SIZE]; //man pcap_lookupdev¿¡¼­ °¡Áö°í ¿Â´Ù.
	char *pcap_lookupdev(char *errbuf);
	const unsigned char * ucpData;

	const struct ether_header * stEH;
	struct pcap_pkthdr stpInfo;

	pcap_t * stpHandle;
	cpNicname=pcap_lookupdev(errbuf);

	if(0==cpNicname)
	{
		perror(errbuf);
		return 0;
	}

	printf("Nicname: [%s] \n", cpNicname);

	stpHandle=pcap_open_live(cpNicname, 1500, 1, 0, errbuf);
	//pcap_t stphandle_open_live(cpNicname, 1500(ethernet), 1(1À»ÇØ¾ß promisc°¡ ÄÑÁø´Ù.ÀÌ°ÍÀú°Í ´Ù ijġ), , );

	if(stpHandle==0)
	{
		perror(errbuf);
		return 0;
	}
	ucpData=pcap_next(stpHandle, &stpInfo);

	Hexaview(ucpData, 0);


	stEH=(struct ether_header *)ucpData;

	printf("=================================================== \n ");
	printf("ETHERNET HEADER Into \n ");
	printf("=================================================== \n ");
	printf("Dest MAC: %02X: %02X: %02X: %02X: %02X: %02X: \n", stEH->ether_dhost[0], stEH->ether_dhost[1], stEH->ether_dhost[2], stEH->ether_dhost[3], stEH->ether_dhost[4], stEH->ether_dhost[5]);
	printf("=================================================== \n ");
	printf("Src MAC: %02X: %02X: %02X: %02X: %02X: %02X: \n", stEH->ether_shost[0], stEH->ether_shost[1], stEH->ether_shost[2], stEH->ether_shost[3], stEH->ether_shost[4], stEH->ether_shost[5]);	
	printf("=================================================== \n ");



	pcap_close(stpHandle);


	return 0;
}

<출력결과>