tcpserver_sample.c

/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * *//** 程序清单：tcp 服务端 * * 这是一个 tcp 服务端的例程 * 导出 tcpserv 命令到控制终端 * 命令调用格式：tcpserv * 无参数 * 程序功能：作为一个服务端，接收并显示客户端发来的数据 ，接收到 exit 退出程序*/#include <rtthread.h>#include <sys/socket.h> /* 使用BSD socket，需要包含socket.h头文件 */#include <netdb.h>#include <string.h>#include <finsh.h>#define BUFSZ (1024)static const char send_data[] = "This is TCP Server from RT-Thread."; /* 发送用到的数据 */static void tcpserv(int argc, char **argv){ char *recv_data; /* 用于接收的指针，后面会做一次动态分配以请求可用内存 */ socklen_t sin_size; int sock, connected, bytes_received; struct sockaddr_in server_addr, client_addr; rt_bool_t stop = RT_FALSE; /* 停止标志 */ int ret; recv_data = rt_malloc(BUFSZ + 1); /* 分配接收用的数据缓冲 */ if (recv_data == RT_NULL) { rt_kprintf("No memory\n"); return; } /* 一个socket在使用前，需要预先创建出来，指定SOCK_STREAM为TCP的socket */ if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { /* 创建失败的错误处理 */ rt_kprintf("Socket error\n"); /* 释放已分配的接收缓冲 */ rt_free(recv_data); return; } /* 初始化服务端地址 */ server_addr.sin_family = AF_INET; server_addr.sin_port = htons(5000); /* 服务端工作的端口 */ server_addr.sin_addr.s_addr = INADDR_ANY; rt_memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero)); /* 绑定socket到服务端地址 */ if (bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) { /* 绑定失败 */ rt_kprintf("Unable to bind\n"); /* 释放已分配的接收缓冲 */ rt_free(recv_data); return; } /* 在socket上进行监听 */ if (listen(sock, 5) == -1) { rt_kprintf("Listen error\n"); /* release recv buffer */ rt_free(recv_data); return; } rt_kprintf("\nTCPServer Waiting for client on port 5000...\n"); while (stop != RT_TRUE) { sin_size = sizeof(struct sockaddr_in); /* 接受一个客户端连接socket的请求，这个函数调用是阻塞式的 */ connected = accept(sock, (struct sockaddr *)&client_addr, &sin_size); /* 返回的是连接成功的socket */ if (connected < 0) { rt_kprintf("accept connection failed! errno = %d\n", errno); continue; } /* 接受返回的client_addr指向了客户端的地址信息 */ rt_kprintf("I got a connection from (%s , %d)\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port)); /* 客户端连接的处理 */ while (1) { /* 发送数据到connected socket */ ret = send(connected, send_data, strlen(send_data), 0); if (ret < 0) { /* 发送失败，关闭这个连接 */ closesocket(connected); rt_kprintf("\nsend error,close the socket.\r\n"); break; } else if (ret == 0) { /* 打印send函数返回值为0的警告信息 */ rt_kprintf("\n Send warning,send function return 0.\r\n"); } /* 从connected socket中接收数据，接收buffer是1024大小，但并不一定能够收到1024大小的数据 */ bytes_received = recv(connected, recv_data, BUFSZ, 0); if (bytes_received < 0) { /* 接收失败，关闭这个connected socket */ closesocket(connected); break; } else if (bytes_received == 0) { /* 打印recv函数返回值为0的警告信息 */ rt_kprintf("\nReceived warning,recv function return 0.\r\n"); closesocket(connected); break; } /* 有接收到数据，把末端清零 */ recv_data[bytes_received] = '\0'; if (strcmp(recv_data, "q") == 0 || strcmp(recv_data, "Q") == 0) { /* 如果是首字母是q或Q，关闭这个连接 */ closesocket(connected); break; } else if (strcmp(recv_data, "exit") == 0) { /* 如果接收的是exit，则关闭整个服务端 */ closesocket(connected); stop = RT_TRUE; break; } else { /* 在控制终端显示收到的数据 */ rt_kprintf("RECEIVED DATA = %s \n", recv_data); } } } /* 退出服务 */ closesocket(sock); /* 释放接收缓冲 */ rt_free(recv_data); return ;}MSH_CMD_EXPORT(tcpserv, a tcp server sample);