ppp.c

PPP拨号协议简单实现 适用于MCU和无系统的嵌入式应用

#include <string.h>
#include "PrjDef.h"
#include "NetDef.h"
#include "config.h"
#include "SerialCom.h"
#include "timer.h"
#include "wdt.h"
#include "Modem.h"
#include "ppp.h"

#define PPP_COUNT 8
#define OUT_TIME 8000

extern uint8 RxBuf[RxBufLen];	
extern uint16 InRx;  

BYTE build=0;
BYTE isEsc;

static volatile int frm_size = 0;

BYTE IPAddress[4];  //拨号后获取的IP地址

BYTE in_buff [PPP_BUFFER_SIZE + 1];		// Input Buffer for PPP data
BYTE out_buff[PPP_BUFFER_SIZE + 1];		// Output Buffer for PPPdata


static const unsigned short fcstab[256] = {
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};


//开始PPP拨号:注意喂狗问题
uint8 dial(char* ISPNo)
{	
    uint32 DialTimeOut;
    
    Debug("\r\nstart dial.\r\n");
    
  	FreeRxBuf();
  	
	SendStr2Modem((uint8*)("atd"), strlen("atd"));
	SendStr2Modem((uint8*)ISPNo, strlen(ISPNo));
	SendStr2Modem((uint8*)("\r"), strlen("\r"));
	
	mstimeout(&DialTimeOut,0);
	
  	while (strstr((char*)RxBuf, "CONNECT") == NULL)
  	{
    	
    	if (strstr((char*)RxBuf, "ERROR") != NULL)
    	{
      		FreeRxBuf();
      		return 0;   //错误
    	}
    	if (mstimeout(&DialTimeOut,8000))
    	{
      		FreeRxBuf();
      		return 0;   //超时
    	}
    	FeedWdt();
  	}
	return 1;   //拨号成功(检测到Connect返回)
}

//写一个字符到Modem串口
void msend(BYTE TheByte)
{
	SendChar2Modem(TheByte);
}

//延迟
void delay(WORD dms)
{
	Delay(dms);
}

//判断超时函数 
BYTE mstimeout(uint32 *timep,uint32 msec)
{
	return(TimeOut(timep,msec));
}

//从Modem串口读取一个字节
BYTE read_mb(char* c)
{
	uint16 i;
	
	if (InRx>0)
	{
		*c=RxBuf[0];
		for(i=1;i<InRx;i++)
			RxBuf[i-1]=RxBuf[i];
		RxBuf[InRx]=0x00;
		InRx--; 
		return 1;
	}
	else
		return 0;
	
}

//内存拷贝,事实上不需要这么麻烦,用memcpy即可
void move (BYTE *src, BYTE *dest, register numBYTEs) 
{
	memcpy((char *)dest,(char *)src,numBYTEs);
}

//open_ppp,这个是执行PPP流程上网的过程,前提是要线发ATD,返回CONNECT后调用.
BYTE open_ppp(void)
{
	char chr;
	BYTE ppp_st;
	uint32 PppTimeOut;	
	
	FreeRxBuf();
	ppp_init(); //初始化缓存,发送第一个空包
	mstimeout(&PppTimeOut,0);
	
	while(1)
	{		
		if (read_mb(&chr))	//单字节读取串口缓存,在移植过程中,这个是需要改动的函数
		{			
			if (ppp_receive(chr)) // ppp_receive:组装PPP包，得到一个完整的PPP包的话，放在 in_buff中，并返回1，否则返回0
			{
				ppp_st=ppp_fsm();    //ppp finity state machine,PPP状态机
				if(ppp_st==PPP_OK)	//PPP成功
				{
					return PPP_OK;	//IP地址在IPAddress[]中.
				}
				else if (ppp_st==LCP_TERMINAL)	//被服务器断开
				{
					Debug("Ppp Terminate");
					return PPP_TML;
				}
			}
		}
		if (mstimeout(&PppTimeOut,8000))	//超时
		{
			disconnect();	//端口后,返回TIMEOUT
			Debug("Ppp TimeOut");
			return PPP_TO;
		}
		FeedWdt();    //喂狗
	}
}

//poll_ppp,这个是PPP的论询函数,在PPP成功后调用.主要目的是接收PPP包,把UDP包提交给UPD层做处理.

BYTE poll_ppp(void)
{
	char chr;
	if (read_mb(&chr))
	{
		if (ppp_receive(chr))
		{
			return ppp_fsm();
		}
	}
	return 0x00;
}

//PPP状态机,里边执行LCP,PAP,IPCP的流程,如果是收到UDP包,则会调用udp_input函数
BYTE ppp_fsm(void)  //ppp finity state machine :when ppp ok and get IP address return 1 else return 0 
{
	WORD protocol;
//	mark
	protocol= in_buff[2]*256+in_buff[3]; //htons(*(WORD *)(&in_buff [2])); //获得PPP协议
		
	switch (protocol)
	{
		case LCP_PACKET:	//LCP包,主要做选项配置
			return do_lcp();
			break;
		case PAP_PACKET:
			break;
		case IPCP_PACKET:	//IPCP,主要用于分配IP地址
			return (do_ipcp());
			break;
		case IP_DATAGRAM:	//IP包
			switch (in_buff [13]) {	//UDP包
				case UDP:
//					udp_input ((udp_pk *)&in_buff[16]); //调用UDP接收函数
					return UDP_DATA;
				default:
					break;
			}
		    break;		
	}
	return 0;
}

//ppp初始化,初始化缓存,并发送第一个包到服务器
void ppp_init (void) {
	memset(in_buff,0x00,PPP_BUFFER_SIZE + 1);
	memset(out_buff,0x00,PPP_BUFFER_SIZE + 1);
	build=0x00;
	send_firstlcp();
}

//空包.这个可作为第一个发送的包,以强制PPP做LCP磋商
void send_firstlcp (void) {
	out_buff [0] = 0xFF;
	out_buff [1] = 0x03;
	out_buff [2] = 0xC0;
	out_buff [3] = 0x21;
	out_buff [4] = 0x01;
	out_buff [5] = 0x00;
	out_buff [6] = 0x00;
    out_buff[7] = 	0x04;
	out_buff[8] = 	0x0D;
	out_buff[9] = 	0xEF;	
	send_ppp ((BYTE *)out_buff, (BYTE)(out_buff[7] + 6));
}

//PPP断开 包

void ppp_terminate(void) {
	out_buff [0] =0xFF; 
	out_buff [1] =0x03; 
	out_buff [2] =0xC0; 
	out_buff [3] =0x21; 
	out_buff [4] =0x05; 
	out_buff [5] =0x01; 
	out_buff [6] =0x00; 
	out_buff [7] =0x04; 
	out_buff [8] =0x00; 
	out_buff [9] =0x00;
	send_ppp (out_buff, 10);
}

BYTE do_lcp (void) 
{
	BYTE *dest = out_buff; 
	BYTE *ptr = (BYTE *)&in_buff[8]; // 配置选项
	switch (in_buff [4] ) {//
		//--------------------------------------------------
		//				收到终止链接请求包                 //
		//--------------------------------------------------
		case TERMINATE: 
			move (in_buff, out_buff, in_buff[7]+6);
			out_buff [4] = TERMINATE_ACK;
			send_ppp ((BYTE *)out_buff, (BYTE)(out_buff[7] + 6));
			Delay(100);
			return LCP_TERMINAL;
			break;
			
		//--------------------------------------------------
		//			配置请求包							   //
		//--------------------------------------------------	
		case REQ:
			if ((in_buff [8] == 0x02) && (in_buff [7] <= 0x0A) ) {
				if ((in_buff [10] == 0xFF) &&(in_buff [11] == 0xFF) &&(in_buff [12] == 0xFF) &&(in_buff [13] == 0xFF)) {
					in_buff [4] = ACK;
					send_ppp (in_buff, (BYTE)(in_buff [7] + 6));
				}
			} else
			//--------------------------------------------------
			// 第一个包，拒绝所有选项，除选项3－密码认证协议  //
			//--------------------------------------------------
			if ((in_buff [8] != 0x03) && (in_buff [7] > 9)) {
				BYTE OptionsSize;
				BYTE Option;
				BYTE Size;
				move (in_buff, out_buff, 8);// move LCP header to output buffer
				out_buff [4] = REJ; // Output will be a reject packet
				dest += 8; // Offset output pointer to LCP options
				OptionsSize = in_buff[7] - 4; // Get size of LCPoptions
				while (OptionsSize > 0) { // Is there options to process?
					Option = *ptr; // Get option number
					Size = *(ptr + 1); // Get size of this option
					OptionsSize -= Size; // Reduce the amount of OptionsSize
					if (Option == 3) { // Is this option 3?
						ptr += Size; // Remove this option in output packet Set New Packet size
						out_buff [7] = out_buff [7] - Size;
					}
					else {
						while (Size-- ) {
							*dest++ = *ptr++;
						}
					}
				}//
				send_ppp ((BYTE *)out_buff, (BYTE)(out_buff[7] + 6));
			} else