net.c

一个运行在PIC上的WEB服务器

/* Network interface functions for 'TCP/IP Lean' (c) Iosoft Ltd. 2000

This software is only licensed for distribution with the book 'TCP/IP Lean',
and may only be used for personal experimentation by the purchaser
of that book, on condition that this copyright notice is retained.
For commercial licensing, contact [e-mail]

This is experimental software; use it entirely at your own risk. The author
offers no warranties of any kind, including its fitness for purpose. */

/*
** v0.01 JPB 19/1/00  Network code split off from TCPFS.C v0.08
** v0.02 JPB 20/1/00  Added support for multiple net drivers
** v0.03 JPB 20/1/00  Improved packet demultiplexing
** v0.04 JPB 28/1/00  Changed 'dispnet' to 'netdebug'
** v0.05 JPB 29/2/00  Fixed bug in non-Ethernet logging
** v0.06 JPB 20/3/00  Added LiteLink and modem support
** v0.07 JPB 23/3/00  Added support for multiple SLIP links
** v0.08 JPB 24/3/00  Fixed multi-channel SLIP interference 
** v0.09 JPB 6/4/00   Fixed type mismatch in SLIP length
** v0.10 JPB 3/7/00   Revised header for book CD
*/

/* Debug option: reverse the order in which IP fragments are sent */
#define SUBFIRST 0  /* Set non-zero to transmit subframes first */
/* Debug options to drop frames on transmit or receive */
#define TXDROP  0   /* Set non-zero to drop 1-in-N transmit frames */
#define RXDROP  0   /* Set non-zero to drop 1-in-N receive frames */

/* All drivers are supported under Borland C
** Packet driver isn't supported under Visual C
** Packet and SLIP drivers aren't supported under DJGPP */
#ifdef __BORLANDC__
#define PKTD_SUPPORT  1
#else
#define PKTD_SUPPORT  0
#endif
#ifdef DJGPP
#define SLIP_SUPPORT 0
#else
#define SLIP_SUPPORT 1
#endif

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>


/* Override the default circular buffer size used in TCPFS.H */
#define _CBUFFLEN_ 0x2000           /* Buffer size: MUST be power of 2 */

#include "netutil.h"
#include "net.h"
#include "ether.h"
#include "serpc.h"
#include "mac.h"

#if PKTD_SUPPORT
#include "pktd.h"
#else                               /* Dummy functions if PKTD not installed */
#define open_pktd(x)        no_driver("packet")
#define close_pktd(x)       no_driver("packet")
#define put_pktd(x, y, z)   no_driver("packet")
#endif

#if !SLIP_SUPPORT                   /* Dummy functions if SLIP not installed */
#define open_slip(x, y)     no_driver("SLIP")
#define close_slip(x)       no_driver("SLIP")
#define put_slip(x, y, z)   no_driver("SLIP")
#define receive_slip(x)     no_driver("SLIP")
#endif

#define SLIP_END 0xc0               /* SLIP escape codes */
#define SLIP_ESC 0xdb
#define ESC_END  0xdc
#define ESC_ESC  0xdd
//extern int SendPacket(unsigned char*, int);

CBUFF rxpkts = {_CBUFFLEN_};        /* Rx and Tx circular packet buffers */
CBUFF txpkts = {_CBUFFLEN_};

BYTE slipbuffs[MAXCOMMS][MAXSLIP];  /* SLIP buffers */
WORD sliplens[MAXCOMMS];            /* ..and data lengths */
int netdebug=3;                       /* Flag to enable net packet display */
//int netdebug=0;
FILE *logfile;                      /* Handle for logfile */
int ndrivers;                       /* Number of initialised drivers */
int txfcount, rxfcount;             /* Counts for 'frame drop' options */
extern  UserBuff UserReceiveBuff;
extern GENFRAME genframe;

/* Private prototypes */
WORD no_driver(char *s);
void do_modem(char c);

/* Get a frame from the network, return length excl. hardware header */
int get_frame(GENFRAME *gfp)
{
   // int rxlen;
    if (UserReceiveBuff.head!=UserReceiveBuff.rear)  //从缓冲区读数据
      {
       genframe.g.len=UserReceiveBuff.length[UserReceiveBuff.head];
       genframe.g.dtype=DTYPE_ETHER;  //以太网类型数据包
       genframe.g.fragoff=0;
       memcpy(genframe.buff,(char *)(&UserReceiveBuff.frame[UserReceiveBuff.head]),genframe.g.len);
         //复制数据
      // ShowFrame(&UserReceiveBuff.frame[UserReceiveBuff.head]);     //打印以太网数据包  
       UserReceiveBuff.head=(UserReceiveBuff.head+1)%UserBuffSize;
       return( genframe.g.len);
      }
    else
      return(0);    
  //  if ((rxlen=get_net(gfp)) > 0)           /* If any packet received.. */
  //  {
  //      if (is_ether(gfp, rxlen))           /* If Ethernet.. */
  //          rxlen -= sizeof(ETHERHDR);      /* Subtract header length */
  //      else if (!is_slip(gfp, rxlen))      /* If not SLIP.. */
  //          rxlen = 0;                      /* Discard if unrecognised */
  //  }
  //return(rxlen);
}

/* Put frame out onto the network; if sub-frame (fragment), send it as well */
int put_frame(GENFRAME *gfp, int len)
{
   // int ret=0/*, len1, len2*/;
  //  GENFRAME *sfp;
    
  //  len1 = gfp->g.fragoff ? gfp->g.fragoff : len;   /* Get len of 2 fragments */
  //  len2 = len - len1;
  //  sfp = (GENFRAME *)&gfp->buff[gfp->g.fragoff];   /* ..and ptr to 2nd frag */
//#if SUBFIRST
  //  if (len2 > 0)                           /* Send sub-frame first.. */
  //      ret = put_net(sfp, (WORD)len2);
  //  if (len1 > 0)                           /* ..then main frame */
  //      ret += put_net(gfp, (WORD)len1);
//#else                                       /* Or send main frame first */
//    if (len1 > 0)
//        ret = put_net(gfp, (WORD)len1);
//    if (len2 > 0)
//        ret += put_net(sfp, (WORD)len2);
//#endif
  if(SendPacket(gfp->buff,len))
    return(len);
  else
    return(0);
  
}




/* Dummy initialisation function for unsupported drivers */
WORD no_driver(char *s)
{
    printf("ERROR: %s driver not included in this version\n", s);
    return(0);
}



/* Get frame from receive buffer, given pointer to a frame buffer.
** If driver type field in the frame buffer is non-zero, match that driver type
** If zero, match any driver type. Return data length (0 if no packet) */
WORD get_net(GENFRAME *gfp)
{
    WORD len=0;
    SNAPFRAME *sfp;
    GENHDR gh={0,0,0};
    LWORD mstim;

    if (buff_dlen(&rxpkts) >= sizeof(GENHDR))
    {                                       /* If frame in Rx pkt buffer.. */
        buff_out(&rxpkts, (BYTE *)&gh, sizeof(gh)); /* Check frame hdr */
        len = gh.len;                       /* ..ensure length is sensible */
        if (len<1 || len>MAXFRAME)
        {
            rxpkts.out = rxpkts.trial = rxpkts.in;
            printf("\nERROR Rx frame buffer corrupt!\n");
            printf("Frame len=%u, type=%u\n", len, gh.dtype);
            len = 0;
        }
        else if (gh.dtype==gfp->g.dtype || !gfp->g.dtype)
        {                                   /* Driver type matches or is 0 */
            buff_out(&rxpkts, gfp->buff, len);  /* Store frame in buffer */
            if (!gfp->g.dtype)              /* If no driver type in buffer.. */
                gfp->g = gh;                /* ..load in complete header */
            gfp->g.len = len;               /* Set length in header */
            if (netdebug)                   /* Display raw frame */
                 disp_frame(gfp, len, 0);
            if (logfile)                    /* Log raw frame */
            {
                mstim = mstime();
                fwrite("GET ", 1, 4, logfile);
                fwrite(&mstim, 1, 4, logfile);
                fwrite(gfp, 1, len+sizeof(GENHDR), logfile);
            }
            if (gfp->g.dtype&DTYPE_ETHER && /* If Ethernet frame.. */
                gfp->buff[MACLEN*2] < 6)    /* ..and Pcol less than 600h */
            {                               /* ..might be 802.3 SNAP */
                sfp = (SNAPFRAME *)gfp->buff;
                if (len>sizeof(SNAPHDR) && sfp->s.lsap==0xaaaa)
                {                           /* If so, convert to DIX */
                    len -= sizeof(SNAPHDR);
                    memmove(&sfp->e.ptype, &sfp->s.ptype, len);
                }
                gfp->g.len = len;           /* Re-set length in header */
            }
        }
        else
        {                                   /* Wrong driver type: discard pkt */
            buff_out(&rxpkts, 0, len);
            len = 0;
        }
#if RXDROP
        if (++txfcount % RXDROP == 0)
        {
            printf("     Rx frame dropped for debug\n");
            len = 0;
        }
#endif
    }
    return(len);
}

/* Put packet onto network, given length */
WORD put_net(GENFRAME *gfp, WORD len)
{
  if(SendPacket(gfp->buff,gfp->g.len))
    return(len);
  else
    return(0);
}