msh调用时对端口进行监听，监听到有客户端连接时，创建新的线程进行连接。
监听时设置最大连接数为4，使用SocketTool工具模拟client连接，实际效果如下。
/*
* Copyright (c) 2006-2019, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2020-02-20 ShineRoyal the first version
*/
#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
static const char *send_data = "hello RT-Thread\n";
struct client_info
{
int socketnum; //socket 号
struct sockaddr_in addr; //socket客户端的ip和port信息
int sockaddrlen; //socketaddr的长度信息
};
void client_thread_entry(void *param)
{
struct client_info* client = param;
rt_kprintf("[%d]%s:%d is connect...\n", client->socketnum, inet_ntoa(client->addr.sin_addr),
ntohs(client->addr.sin_port));
send(client->socketnum, (const void* )send_data, strlen(send_data), 0);
while (1)
{
char str[100];
memset(str, 0, sizeof(str));
int bytes = recv(client->socketnum, str, sizeof(str), 0);
if (bytes == 0)
goto __exit;
rt_kprintf("[%d]%s:%d=>%s...\n", client->socketnum, inet_ntoa(client->addr.sin_addr),
ntohs(client->addr.sin_port), str);
send((int )client->socketnum, (const void * )str, (size_t )strlen(str), 0);
}
__exit: rt_kprintf("[%d]%s:%d is disconnect...\n", client->socketnum, inet_ntoa(client->addr.sin_addr),
ntohs(client->addr.sin_port));
rt_free(client);
closesocket(client->socketnum);
}
void tcpserver(int argc, char **argv)
{
rt_thread_t tid = RT_NULL;
int sock_listen, sock_connect, port;
struct hostent *host;
struct sockaddr_in listen_addr;
struct sockaddr_in connect_addr;
const char *url;
url = "192.168.1.42"; //localhost ip
port = 5000;
/* 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 = (struct hostent *) gethostbyname(url);
if ((sock_listen = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
rt_kprintf("Socket error\n");
return;
}
/* 初始化预连接的服务端地址 */
listen_addr.sin_family = AF_INET;
listen_addr.sin_port = htons(port);
listen_addr.sin_addr = *((struct in_addr *) host->h_addr);
rt_memset(&(listen_addr.sin_zero), 0, sizeof(listen_addr.sin_zero));
if (bind(sock_listen, (struct sockaddr * )&listen_addr, sizeof(struct sockaddr)) < 0)
{
rt_kprintf("Bind fail!\n");
goto __exit;
}
listen(sock_listen, 3);
rt_kprintf("begin listing...\n");
while (1)
{
int sin_size = sizeof(struct sockaddr_in);
sock_connect = accept(sock_listen, (struct sockaddr* )&connect_addr, (socklen_t* )&sin_size);
if (sock_connect == -1)
{
rt_kprintf("no socket,waitting others socket disconnect.\n");
continue;
}
char tid_name[10] = "cli";
char tid_num[10];
itoa(sock_connect, tid_num, 10);
strcat(tid_name, tid_num);
struct client_info *client;
client = rt_malloc(sizeof(struct client_info));
client->socketnum = sock_connect;
memcpy(&client->addr, &connect_addr, sizeof(struct sockaddr_in));
client->sockaddrlen = sin_size;
tid = rt_thread_create(tid_name, client_thread_entry, (void*) client, 4096, 25, 10);
if (tid == RT_NULL)
{
rt_kprintf("no memery for thread %s startup failed!\n", tid_name);
rt_free(client);
continue;
}
rt_thread_startup(tid);
}
__exit: rt_kprintf("close listener...\n");
/* 关闭这个 socket */
closesocket(sock_listen);
}
MSH_CMD_EXPORT(tcpserver, tcpserver);