最简单的回声服务器源码

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

#define SERVER_PORT 666

int main(void){

int sock;//代表信箱 struct sockaddr_in server_addr;

//1.创建信箱 sock = socket(AF_INET, SOCK_STREAM, 0);

//2.清空标签，写上地址和端口号 bzero(&server_addr, sizeof(server_addr));

server_addr.sin_family = AF_INET;//选择协议族IPV4 server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//监听本地所有IP地址 server_addr.sin_port = htons(SERVER_PORT);//绑定端口号

//实现标签贴到收信得信箱上 bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr));

//把信箱挂置到传达室，这样，就可以接收信件了 listen(sock, 128);

//万事俱备，只等来信 printf("等待客户端的连接 ");

int done =1;

while(done){ struct sockaddr_in client; int client_sock, len; char client_ip[64]; char buf[256];

socklen_t client_addr_len; client_addr_len = sizeof(client); client_sock = accept(sock, (struct sockaddr *)&client, &client_addr_len);

//打印客服端IP地址和端口号 printf("client ip: %s port : %d ", inet_ntop(AF_INET, &client.sin_addr.s_addr,client_ip,sizeof(client_ip)), ntohs(client.sin_port)); /*读取客户端发送的数据*/ len = read(client_sock, buf, sizeof(buf)-1); buf[len] = ; printf("receive[%d]: %s ", len, buf);

//转换成大写 for(i=0; i<len; i++){ /*if(buf[i]>=a && buf[i]<=z){ buf[i] = buf[i] - 32; }*/ buf[i] = toupper(buf[i]); }

len = write(client_sock, buf, len);

printf("finished. len: %d ", len); close(client_sock);

} close(sock); return 0; }

#include #include #include #include #include #include #include #define SERVER_PORT 666 int main(void){ int sock;//代表信箱 struct sockaddr_in server_addr; //1.创建信箱 sock = socket(AF_INET, SOCK_STREAM, 0); //2.清空标签，写上地址和端口号 bzero(&server_addr, sizeof(server_addr)); server_addr.sin_family = AF_INET;//选择协议族IPV4 server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//监听本地所有IP地址 server_addr.sin_port = htons(SERVER_PORT);//绑定端口号 //实现标签贴到收信得信箱上 bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)); //把信箱挂置到传达室，这样，就可以接收信件了 listen(sock, 128); //万事俱备，只等来信 printf("等待客户端的连接 "); int done =1; while(done){ struct sockaddr_in client; int client_sock, len; char client_ip[64]; char buf[256]; socklen_t client_addr_len; client_addr_len = sizeof(client); client_sock = accept(sock, (struct sockaddr *)&client, &client_addr_len); //打印客服端IP地址和端口号 printf("client ip: %s port : %d ", inet_ntop(AF_INET, &client.sin_addr.s_addr,client_ip,sizeof(client_ip)), ntohs(client.sin_port)); /*读取客户端发送的数据*/ len = read(client_sock, buf, sizeof(buf)-1); buf[len] = ; printf("receive[%d]: %s ", len, buf); //转换成大写 for(i=0; i =a && buf[i]<=z){ buf[i] = buf[i] - 32; }*/ buf[i] = toupper(buf[i]); } len = write(client_sock, buf, len); printf("finished. len: %d ", len); close(client_sock); } close(sock); return 0; }