add more Chinese comments.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@536 bbd45198-f89e-11dd-88c7-29a3b14d5316

1 files changed, 95 insertions, 82 deletions

diff --git a/examples/network/tcpserver.c b/examples/network/tcpserver.c
index 606e842c8d..9fa7bc8fb8 100644
--- a/examples/network/tcpserver.c
+++ b/examples/network/tcpserver.c
@@ -1,109 +1,122 @@
 #include <rtthread.h>

-#include <lwip/sockets.h>

+#include <lwip/sockets.h> /* 使用BSD Socket接口必须包含sockets.h这个头文件 */

 

-static const char send_data[] = "This is TCP Server from RT-Thread.";

+static const char send_data[] = "This is TCP Server from RT-Thread."; /* 发送用到的数据 */

 void tcpserv(void* parameter)

 {

-	char *recv_data;

-	rt_uint32_t sin_size;

-	int sock, connected, bytes_received;

-	struct sockaddr_in server_addr, client_addr;

-    rt_bool_t stop = RT_FALSE;

+   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 */

+   rt_uint32_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 */

 

-    recv_data = rt_malloc(1024);

-    if (recv_data == RT_NULL)

-    {

-        rt_kprintf("No memory\n");

-        return;

-    }

+   recv_data = rt_malloc(1024); /* 分配接收用的数据缓冲 */

+   if (recv_data == RT_NULL)

+   {

+       rt_kprintf("No memory\n");

+       return;

+   }

 

-    /* create a socket */

-	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)

-	{

-		rt_kprintf("Socket error\n");

+   /* 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");

 

-        /* release recv buffer */

-        rt_free(recv_data);

-		return;

-	}

+       /* 释放已分配的接收缓冲 */

+       rt_free(recv_data);

+       return;

+   }

 

-    /* init server address */

-	server_addr.sin_family = AF_INET;

-	server_addr.sin_port = htons(5000);

-	server_addr.sin_addr.s_addr = INADDR_ANY;

-	rt_memset(&(server_addr.sin_zero),8, sizeof(server_addr.sin_zero));

+   /* 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),8, sizeof(server_addr.sin_zero));

 

-    /* bind socket */

-	if (bind(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)

-	{

-		rt_kprintf("Unable to bind\n");

+   /* 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");

 

-        /* release recv buffer */

-        rt_free(recv_data);

-		return;

-	}

+       /* 释放已分配的接收缓冲 */

+       rt_free(recv_data);

+       return;

+   }

 

-    /* listen socket */

-	if (listen(sock, 5) == -1)

-	{

-		rt_kprintf("Listen error\n");

+   /* 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;

-	}

+       /* 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);

+   rt_kprintf("\nTCPServer Waiting for client on port 5000...\n");

+   while(stop != RT_TRUE)

+   {

+       sin_size = sizeof(struct sockaddr_in);

 

-        /* accept a client socket */

-		connected = accept(sock, (struct sockaddr *)&client_addr, &sin_size);

+       /* 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 */

 

-		rt_kprintf("I got a connection from (%s , %d)\n",

-			   inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));

+       /* 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));

 

-		while (1)

-		{

-            send(connected, send_data, strlen(send_data), 0);

+       /* 客户端连接的处理 */

+       while (1)

+       {

+           /* 发送数据到connected socket */

+           send(connected, send_data, strlen(send_data), 0);

 

-			bytes_received = recv(connected,recv_data, 1024, 0);

-			if (bytes_received < 0)

-			{

-			    /* close socket */

-			    lwip_close(connected);

-			    break;

-			}

+           /* 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, 1024, 0);

+           if (bytes_received < 0)

+           {

+               /* 接收失败，关闭这个connected socket */

+               lwip_close(connected);

+               break;

+           }

 

-			recv_data[bytes_received] = '\0';

-			if (strcmp(recv_data , "q") == 0 || strcmp(recv_data , "Q") == 0)

-			{

-				lwip_close(connected);

-				break;

-			}

-			else if (strcmp(recv_data, "exit") == 0)

-			{

-			    lwip_close(connected);

-			    stop = RT_TRUE;

-			    break;

-			}

-			else

-			{

-				rt_kprintf("RECIEVED DATA = %s \n" , recv_data);

-			}

-		}

-	}

+           /* 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 */

+               lwip_close(connected);

+               break;

+           }

+           else if (strcmp(recv_data, "exit") == 0)

+           {

+               /* 如果接收的是exit，则关闭整个服务端 */

+               lwip_close(connected);

+               stop = RT_TRUE;

+               break;

+           }

+           else

+           {

+               /* 在控制终端显示收到的数据 */

+               rt_kprintf("RECIEVED DATA = %s \n" , recv_data);

+           }

+       }

+   }

 

-	lwip_close(sock);

+   /* 退出服务 */

+   lwip_close(sock);

 

-	/* release recv buffer */

-	rt_free(recv_data);

+   /* 释放接收缓冲 */

+   rt_free(recv_data);

 

-	return ;

+   return ;

 }

 

 #ifdef RT_USING_FINSH

 #include <finsh.h>

+/* 输出tcpserv函数到finsh shell中 */

 FINSH_FUNCTION_EXPORT(tcpserv, startup tcp server);

 #endif