socket 기본 server, client 소스

hello_server.c

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>

void error_handling(char *message);

int main(int argc, char *argv[]){
        int serv_sock;
        int clnt_sock;

        struct sockaddr_in serv_addr;
        struct sockaddr_in clnt_addr;
        socklen_t clnt_addr_size;

        char message[]="Hello World!";

        if(argc!=2){
                printf("Usage : %s <port>\n", argv[0]);
                exit(1);
        }

        serv_sock=socket(PF_INET, SOCK_STREAM, 0);
        if(serv_sock == -1)
                error_handling("socket() error");

        memset(&serv_addr, 0, sizeof(serv_addr));
                serv_addr.sin_family=AF_INET;
        serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
        serv_addr.sin_port=htons(atoi(argv[1]));

        if(bind(serv_sock, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) == -1)
                error_handling("bind() error");

        if(listen(serv_sock, 5) == -1)
                error_handling("listen() error");

        clnt_addr_size = sizeof(clnt_addr);
        clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_addr, &clnt_addr_size);
        if(clnt_sock==-1)
                error_handling("accept() error");

        write(clnt_sock, message, sizeof(message));
        close(clnt_sock);
        close(serv_sock);
        return 0;
}

void error_handling(char *message){
        fputs(message, stderr);
        fputc('\n', stderr);
        exit(1);
}

 

hello_clinet.c

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<sys/socket.h>

void error_handling(char *message);

int main(int argc, char *argv[]){
        int sock;
        struct sockaddr_in serv_addr;
        char message[30];
        int str_len;

        if(argc!=3){
                printf("Usage : %s <IP> <port>\n", argv[0]);
        }

        sock = socket(PF_INET, SOCK_STREAM, 0);
        if(sock == -1)
                error_handling("socket() error");

        memset(&serv_addr, 0, sizeof(serv_addr));
        serv_addr.sin_family=AF_INET;
        serv_addr.sin_addr.s_addr=inet_addr(argv[1]);
        serv_addr.sin_port=htons(atoi(argv[2]));

        if(connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1)
                error_handling("connect() error!");

        str_len=read(sock, message, sizeof(message)-1);
        if(str_len==-1)
                error_handling("read() error!");

        printf("Message from server : %s \n", message);
        close(sock);
        return 0;

}

void error_handling(char *message){
        fputs(message, stderr);
        fputc('\n', stderr);
        exit(1);
}