#if 1
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include "lwip/tcp.h"
#include "lwip/err.h"
#include "lwip/memp.h"
#include "lwip/inet.h"
/ 回调函数控制宏
#define USE_ERROR_CALLBACK 1
#define USE_SENT_CALLBACK 0
#define USE_POLL_CALLBACK 0
/ 调试信息输出 //
#define DEBUG
#ifdef DEBUG
#define debug(fmt, ...) do{printf(fmt, ##__VA_ARGS__);}while(0)
#else
#define debug(fmt, ...) do{;}while(0)
#endif
/ tcp接收发送缓存 ///
#define TCP_RX_LEN 8192
uint8_t TCP_RX_BUF[TCP_RX_LEN];
volatile uint16_t TCP_RX_STA = 0; /* bit15：有无数据标志位 bit14-0:数据量计数 */
/ TCP结构句柄 ///
struct tcp_pcb* tcppcb = NULL;
/ 本地函数定义 ///
static void tcp_server_disconnect(struct tcp_pcb *tpcb);
static uint32_t tcp_server_send(struct tcp_pcb *tpcb, const void* buf, uint32_t len);
/ 私有函数实现 ///
#if (USE_ERROR_CALLBACK == 1)
static void error_callback(void *arg, err_t err)
{
debug("\r\n error_callback:%d.", err);
}
#endif
#if (USE_ERROR_CALLBACK == 1)
static void error_callback(void *arg, err_t err)
{
debug("\r\n error_callback:%d.", err);
switch(err)
{
/* PC上位机如果正常运行中闪退或者不良退出会出现这个错误，此时服务器需要释放掉连接 */
case ERR_RST:
tcp_server_disconnect(tcppcb);
break;
default:break;
}
}
#endif
static err_t recv_callback(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
if (p == NULL) /* 接收到空包表示对方断开连接 */
{
tcp_server_disconnect(tpcb);
err = ERR_CLSD;
}
else if (err != ERR_OK) /* 收到非空包但是出现错误 */
{
pbuf_free(p);
}
else /* 接收数据正常，遍历pbuf拷贝出接收到的数据 */
{
struct pbuf* it = p;
if ((TCP_RX_STA & 0x8000) == 0) /* 当前缓存为空 */
{
for (it = p; it != NULL; it = it->next)
{
if (TCP_RX_STA + it->len > TCP_RX_LEN) /* 缓存满了 */
break;
memcpy(TCP_RX_BUF + TCP_RX_STA, it->payload, it->len); /* 将接收到的数据拷贝到自己的缓存中 */
TCP_RX_STA += it->len;
}
TCP_RX_STA |= 0x8000; /* 标记有数据收到 */
}
tcp_recved(tpcb, p->tot_len); /* 滑动TCP窗口 */
pbuf_free(p); /* 释放pbuf */
}
return err;
}
static err_t accept_callback(void *arg, struct tcp_pcb *newpcb, err_t err)
{
if (tcppcb == NULL)
{
if (err == ERR_OK)
{
tcppcb = newpcb;
tcp_arg(newpcb, NULL);
tcp_recv(newpcb, recv_callback);
#if (USE_ERROR_CALLBACK == 1)
tcp_err(newpcb, error_callback);
#endif
#if (USE_SENT_CALLBACK == 1)
tcp_sent(newpcb, sent_callback);
#endif
#if (USE_POLL_CALLBACK == 1)
tcp_poll(newpcb, poll_callback, 1);
#endif
debug("\r\n %s:%d connect.", inet_ntoa(newpcb->remote_ip), newpcb->remote_port);
}
else
{
tcp_server_disconnect(newpcb);
}
}
else
{
tcp_abort(newpcb);
debug("\r\n already connected. ");
}
return err;
}
static void tcp_server_disconnect(struct tcp_pcb *tpcb)
{
tcp_arg(tpcb, NULL);
tcp_recv(tpcb, NULL);
#if (USE_SENT_CALLBACK == 1)
tcp_sent(tpcb, NULL);
#endif
#if (USE_POLL_CALLBACK == 1)
tcp_poll(tpcb, NULL, 0);
#endif
#if (USE_ERROR_CALLBACK == 1)
tcp_err(tpcb, NULL);
#endif
tcp_abort(tpcb); /* 关闭连接并释放tpcb控制块 */
tcppcb = NULL;
debug("\r\n disconnected.");
}
static uint32_t tcp_server_send(struct tcp_pcb *tpcb, const void* buf, uint32_t len)
{
uint32_t nwrite = 0, total = 0;
const uint8_t* p = (const uint8_t *) buf;
err_t err = ERR_OK;
if (!tpcb)
return 0;
while ((err == ERR_OK) && (len != 0) && (tcp_sndbuf(tpcb) > 0))
{
nwrite = tcp_sndbuf(tpcb) >= len ? len : tcp_sndbuf(tpcb);
err = tcp_write(tpcb, p, nwrite, 1);
if (err == ERR_OK)
{
len -= nwrite;
total += nwrite;
p += nwrite;
}
tcp_output(tpcb);
}
return total;
}
/ 导出以下函数供外部调用 ///
//extern int tcp_server_start(uint16_t port);
//extern int user_senddata(const void* buf,uint32_t len);
//extern int transfer_data();
/**
* 启动TCP服务器
* @param port 本地端口号
* @return 成功返回0
*/
int tcp_server_start(uint16_t port)
{
int ret = 0;
struct tcp_pcb* pcb = NULL;
err_t err = ERR_OK;
/* create new TCP PCB structure */
pcb = tcp_new();
if (!pcb)
{
debug("Error creating PCB. Out of Memory\n\r");
ret = -1;
goto __exit;
}
/* bind to specified @port */
err = tcp_bind(pcb, IP_ADDR_ANY, port);
if (err != ERR_OK)
{
debug("Unable to bind to port %d: err = %d\n\r", port, err);
ret = -2;
goto __exit;
}
/* listen for connections */
pcb = tcp_listen(pcb);
if (!pcb)
{
debug("Out of memory while tcp_listen\n\r");
ret = -3;
}
/* specify callback to use for incoming connections */
tcp_accept(pcb, accept_callback);
/* create success */
debug("TCP echo server started @ port %d\n\r", port);
return ret;
__exit:
if (pcb)
memp_free(MEMP_TCP_PCB, pcb);
return ret;
}
/**
* TCP发送数据
* @param buf 待发送的数据
* @param len 数据长度
* @return 返回实际发送的字节数
*/
int user_senddata(const void* buf, uint32_t len)
{
return tcp_server_send(tcppcb, buf, len);
}
/**
* 轮询函数，放置于main函数的while死循环中
* @return 无
*/
int transfer_data()
{
uint32_t nsend = 0;
if (tcppcb != NULL && tcppcb->state == ESTABLISHED) /* 连接有效 */
{
if (TCP_RX_STA & 0x8000) /* 有数据收到 */
{
nsend = user_senddata(TCP_RX_BUF, TCP_RX_STA & 0x7FFF); /* 将接收到的数据发回去 */
TCP_RX_STA = 0;
debug("\r\n send %d bytes success.", nsend);
}
}
return 0;
}
#endif
