rt-thread/examples/network/tcpclient.c

123 lines
3.5 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

#include <rtthread.h>
#include <lwip/netdb.h> /* 为了解析主机名需要包含netdb.h头文件 */
#include <lwip/sockets.h> /* 使用BSD socket需要包含sockets.h头文件 */
#define BUFSZ 1024
static const char send_data[] = "This is TCP Client from RT-Thread."; /* 发送用到的数据 */
void tcpclient(const char* url, int port)
{
int ret;
char *recv_data;
struct hostent *host;
int sock, bytes_received;
struct sockaddr_in server_addr;
/* 通过函数入口参数url获得host地址如果是域名会做域名解析 */
host = gethostbyname(url);
/* 分配用于存放接收数据的缓冲 */
recv_data = rt_malloc(BUFSZ);
if (recv_data == RT_NULL)
{
rt_kprintf("No memory\n");
return;
}
/* 创建一个socket类型是SOCKET_STREAMTCP类型 */
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
/* 创建socket失败 */
rt_kprintf("Socket error\n");
/* 释放接收缓冲 */
rt_free(recv_data);
return;
}
/* 初始化预连接的服务端地址 */
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(port);
server_addr.sin_addr = *((struct in_addr *)host->h_addr);
rt_memset(&(server_addr.sin_zero), 0, sizeof(server_addr.sin_zero));
/* 连接到服务端 */
if (connect(sock, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1)
{
/* 连接失败 */
rt_kprintf("Connect fail!\n");
lwip_close(sock);
/*释放接收缓冲 */
rt_free(recv_data);
return;
}
while(1)
{
/* 从sock连接中接收最大BUFSZ - 1字节数据 */
bytes_received = recv(sock, recv_data, BUFSZ - 1, 0);
if (bytes_received < 0)
{
/* 接收失败,关闭这个连接 */
lwip_close(sock);
rt_kprintf("\nreceived error,close the socket.\r\n");
/* 释放接收缓冲 */
rt_free(recv_data);
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");
continue;
}
/* 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(sock);
rt_kprintf("\n got a 'q' or 'Q',close the socket.\r\n");
/* 释放接收缓冲 */
rt_free(recv_data);
break;
}
else
{
/* 在控制终端显示收到的数据 */
rt_kprintf("\nReceived data = %s " , recv_data);
}
/* 发送数据到sock连接 */
ret = send(sock,send_data,strlen(send_data), 0);
if (ret < 0)
{
/* 接收失败,关闭这个连接 */
lwip_close(sock);
rt_kprintf("\nsend error,close the socket.\r\n");
rt_free(recv_data);
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");
}
}
return;
}
#ifdef RT_USING_FINSH
#include <finsh.h>
/* 输出tcpclient函数到finsh shell中 */
FINSH_FUNCTION_EXPORT(tcpclient, startup tcp client);
#endif