TCP/IP (C++)

TCP 

- 연결형 프로토콜

- UDP 보다 속도 느림

- 패킷의 순서 보장

- 3-Way handshaking

아래 두 샘플은 linux 기반

TCP Server

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <time.h>

int main(int argc, char *argv[])

{

int listenfd = 0, connfd = 0;

struct sockaddr_in serv_addr;

char sendBuff[1025];

time_t ticks;

listenfd = socket(AF_INET, SOCK_STREAM, 0);

memset(&serv_addr, '0', sizeof(serv_addr));

memset(sendBuff, '0', sizeof(sendBuff));

serv_addr.sin_family = AF_INET;

serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

serv_addr.sin_port = htons(9000);

bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));

listen(listenfd, 10);

while(1)

{

connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);

ticks = time(NULL);

snprintf(sendBuff, sizeof(sendBuff), "%.24s\r\n", ctime(&ticks));

write(connfd, sendBuff, strlen(sendBuff));

close(connfd);

sleep(1);

}

}

TCP Client

#include <sys/socket.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <netdb.h>

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <arpa/inet.h>

int main(int argc, char *argv[])

{

int sockfd = 0, n = 0;

char recvBuff[1024];

struct sockaddr_in serv_addr;

if(argc != 2)

{

printf("\n Usage: %s <ip of server> \n",argv[0]);

return 1;

}

memset(recvBuff, '0',sizeof(recvBuff));

if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)

{

printf("\n Error : Could not create socket \n");

return 1;

}

memset(&serv_addr, '0', sizeof(serv_addr));

serv_addr.sin_family = AF_INET;

serv_addr.sin_port = htons(9000);

if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)

{

printf("\n inet_pton error occured\n");

return 1;

}

if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)

{

printf("\n Error : Connect Failed \n");

return 1;

}

while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)

{

recvBuff[n] = 0;

if(fputs(recvBuff, stdout) == EOF)

{

printf("\n Error : Fputs error\n");

}

}

if(n < 0)

{

printf("\n Read error \n");

}

return 0;

}