RT-Thread-TCP Connect fail,求助~RT-Thread问答社区

TCP Connect fail,求助~

发布于 2019-10-06 20:20:40 浏览：2859 订阅该版

使用时出现TCP无法连接的情况

目前LWIP已经能跑起来，可以Ping通，但是使用实例程序时出现TCp无法连接的情况，MSH输出的Log如下
```
tcpclient 192.168.1.9 50010
lwip_socket(PF_INET, SOCK_STREAM, 0) = 0
lwip_connect(0, addr=192.168.1.9 port=50010)
lwip_connect(0) failed, err=-4
Connect fail!
lwip_close(0)
```

其中 192.168.1.9是我的PC，PC已经使用网络助手开启了TCP Server，监听端口为 50010,192.168.1.30为设备端
使用PC的ping命令可以Ping通，如下所示：
```
Reply from 192.168.1.30: bytes=32 time=1ms TTL=255
Reply from 192.168.1.30: bytes=32 time<1ms TTL=255
Reply from 192.168.1.30: bytes=32 time<1ms TTL=255
Reply from 192.168.1.30: bytes=32 time=1ms TTL=255
Reply from 192.168.1.30: bytes=32 time=1ms TTL=255
Reply from 192.168.1.30: bytes=32 time=1ms TTL=255
```

TCP Client例程如下
```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 客户端
 *
 * 这是一个 tcp 客户端的例程
 * 导出 tcpclient 命令到控制终端
 * 命令调用格式：tcpclient URL PORT
 * URL：服务器地址 PORT:：端口号
 * 程序功能：接收并显示从服务端发送过来的信息，接收到开头是 'q' 或 'Q' 的信息退出程序
*/
#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 Client from RT-Thread."; /* 发送用到的数据 */
void tcpclient(int argc, char **argv)
{
 int ret;
 char *recv_data;
 struct hostent *host;
 int sock, bytes_received;
 struct sockaddr_in server_addr;
 const char *url;
 int port;
 if (argc < 3)
 {
 rt_kprintf("Usage: tcpclient URL PORT ");
 rt_kprintf("Like: tcpclient 192.168.1.9 50010 ");
 return ;
 }
 url = argv[1];
 port = strtoul(argv[2], 0, 10);
 /* 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 ");
 return;
 }
 /* 创建一个socket，类型是SOCKET_STREAM，TCP类型 */
 if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
 {
 /* 创建socket失败 */
 rt_kprintf("Socket error ");
 /* 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! ");
 closesocket(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 */
 closesocket(sock);
 rt_kprintf(" received error,close the socket. ");
 /* 释放接收缓冲 */
 rt_free(recv_data);
 break;
 }
 else if (bytes_received == 0)
 {
 /* 默认 recv 为阻塞模式，此时收到0认为连接出错，关闭这个连接 */
 closesocket(sock);
 rt_kprintf(" received error,close the socket. ");
 /* 释放接收缓冲 */
 rt_free(recv_data);
 break;
 }
 /* 有接收到数据，把末端清零 */
 recv_data[bytes_received] = '\0';
 if (strncmp(recv_data, "q", 1) == 0 || strncmp(recv_data, "Q", 1) == 0)
 {
 /* 如果是首字母是q或Q，关闭这个连接 */
 closesocket(sock);
 rt_kprintf(" got a 'q' or 'Q',close the socket. ");
 /* 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(" Received 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 */
 closesocket(sock);
 rt_kprintf(" send error,close the socket. ");
 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(" Send warning,send function return 0. ");
 }
 }
 return;
}
MSH_CMD_EXPORT(tcpclient, a tcp client sample);
```
经测试，不仅是TCP Client有问题，TCP Server和UDP都不能正常通信...

断点跟进，发现会进入到lwip_connect函数的这个语句`"lwip_connect: invalid address"`

```c
LWIP_ERROR("lwip_connect: invalid address", IS_SOCK_ADDR_LEN_VALID(namelen) &&
               IS_SOCK_ADDR_TYPE_VALID_OR_UNSPEC(name) && IS_SOCK_ADDR_ALIGNED(name),
               sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
```

以下是 lwip_connect 函数
```c
int
lwip_connect(int s, const struct sockaddr *name, socklen_t namelen)
{
  struct lwip_sock *sock;
  err_t err;

sock = get_socket(s);
  if (!sock) {
    return -1;
  }

if (!SOCK_ADDR_TYPE_MATCH_OR_UNSPEC(name, sock)) {
    /* sockaddr does not match socket type (IPv4/IPv6) */
    sock_set_errno(sock, err_to_errno(ERR_VAL));
    return -1;
  }

LWIP_UNUSED_ARG(namelen);
 if (name->sa_family == AF_UNSPEC) {
 LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, AF_UNSPEC) ", s));
 err = netconn_disconnect(sock->conn);
 } else {
 ip_addr_t remote_addr;
 u16_t remote_port;

/* check size, family and alignment of 'name' */
    LWIP_ERROR("lwip_connect: invalid address", IS_SOCK_ADDR_LEN_VALID(namelen) &&
               IS_SOCK_ADDR_TYPE_VALID_OR_UNSPEC(name) && IS_SOCK_ADDR_ALIGNED(name),
               sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);

SOCKADDR_TO_IPADDR_PORT(name, &remote_addr, remote_port);
 LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, addr=", s));
 ip_addr_debug_print_val(SOCKETS_DEBUG, remote_addr);
 LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F") ", remote_port));

#if LWIP_IPV4 && LWIP_IPV6
    /* Dual-stack: Unmap IPv4 mapped IPv6 addresses */
    if (IP_IS_V6_VAL(remote_addr) && ip6_addr_isipv4mappedipv6(ip_2_ip6(&remote_addr))) {
      unmap_ipv4_mapped_ipv6(ip_2_ip4(&remote_addr), ip_2_ip6(&remote_addr));
      IP_SET_TYPE_VAL(remote_addr, IPADDR_TYPE_V4);
    }
#endif /* LWIP_IPV4 && LWIP_IPV6 */

err = netconn_connect(sock->conn, &remote_addr, remote_port);
  }

if (err != ERR_OK) {
 LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) failed, err=%d ", s, err));
 sock_set_errno(sock, err_to_errno(err));
 return -1;
 }

LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) succeeded ", s));
 sock_set_errno(sock, 0);
 return 0;
}
```

请大神们指点迷津~