tcpip

ch04/echo_client.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUF_SIZE	1024
+void error_handling(char *message);
+
+int main(int argc,char *argv[]){
+	int sock;
+	struct sockaddr_in serv_addr;
+	char message[BUF_SIZE];
+	int str_len;
+
+	if(argc != 3){
+		printf("Usage : %s <IP> <port>\n",argv[0]);
+		exit(1);
+	}
+
+	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\r\n");
+	}else{
+		printf("Connected....");
+	}
+
+	while(1){
+		printf("Input message(Q to quit):");
+		fgets(message,BUF_SIZE,stdin);
+
+		if(!strcmp(message,"q\n") || !strcmp(message,"Q\n"))
+			break;
+		write(sock,message,strlen(message));
+		str_len = read(sock,message,BUF_SIZE-1);
+		message[str_len] = 0;
+
+		printf("Message from server : %s \n",message);
+	}
+	close(sock);
+	return 0;
+}
+
+void error_handling(char *message){
+	fputs(message,stderr);
+	fputs("\n",stderr);
+	exit(1);
+}

ch04/echo_server.c

@@ -0,0 +1,69 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUF_SIZE 	1024
+void error_handling(char *message);
+
+int main(int argc, char *argv[]){
+	int serv_sock;
+	int clnt_sock;
+
+	char message[BUF_SIZE];
+	int str_len,i;
+	struct sockaddr_in serv_addr;
+	struct sockaddr_in clnt_addr;
+	socklen_t clnt_addr_size;
+
+	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);
+	for(i=0;i<5;i++){
+		clnt_sock = accept(serv_sock,(struct sockaddr *)&clnt_addr,&clnt_addr_size);
+		if(clnt_sock == -1){
+			error_handling("accept() error");
+		}else{
+			printf("Connected client %d\n",i+1);
+		}
+		while((str_len = read(clnt_sock,message,BUF_SIZE)) != 0)
+		{	
+			write(clnt_sock,message,str_len);
+			printf("client %d:message %s",i+1,message);
+		}
+		close(clnt_sock);
+	}
+	close(serv_sock);
+
+	return 0;
+
+}
+
+void error_handling(char *message){
+
+	fputs(message,stderr);
+	fputs("\n",stderr);
+	exit(1);
+}