ppp_loop.c

在ARM7和UC/OSII的平台上实现了GPS自动报站的功能,涉及GPS模块LEA_4S的驱动,位置速寻算法,语音芯片ISD4004的录放音驱动,LED页面管理等等.从启动代码到操作系统的移植以及到业

/*
 * FILENAME: ppp_loop.c
 *
 * Copyright 1997 - 2001 By InterNiche Technologies Inc. All rights reserved
 *
 * Loopback line driver for InterNiche PPP
 *
 * MODULE: PPP
 *
 * ROUTINES: pl_connect(), pl_hangup(), pl_putc(), pl_write(), 
 * ROUTINES: pl_speed(), pl_state(),
 *
 * PORTABLE: yes
 */


#include "ipport.h"

#ifdef USE_PPP          /* whole file can be ifdeffed out */

#include "ppp_port.h"

#ifdef LB_XOVER         /* file can be ifdeffed on this too */

#include "mppp.h"
#include "ppp_loop.h"
#include "ip.h"


/* list of existing loopback devices. Devices are added to the list as
 * they are created. When a device initiates a connection (thus becoming
 * a client) a disconnected device is selceted from the list to be it's
 * server. If there are no free devices then the client open fails.
 */

M_PPP lb_mppps[MAX_LBXOVERS];

/* also keep a list of connected endpoints for the above links. IE if
 * lb_mppp[0] is logically connected, it's "other end" will be in
 * lb_otherend[0]. These entrys have no meaning if the state of
 * the lb_mppp[] entry's line is not LN_CONNECTED.
 */

M_PPP lb_otherend[MAX_LBXOVERS];


/* FUNCTION: pl_lookup()
 *
 * find the index into lb_mppp table which matchs the passed M_PPP
 * pointer. 
 *
 * PARAM1: M_PPP
 *
 * RETURNS: index of entry from lb_mppp table, or -1 is not found.
 */

int
pl_lookup(M_PPP mppp)
{
   int   i;

   for(i = 0; i < MAX_LBXOVERS; i++)
   {
      if(lb_mppps[i] == mppp)
         return i;
   }
   return -1;
}

/* FUNCTION: pl_lookup()
 *
 * Find the loopback mppp connected to a passed mppp.
 *
 * PARAM1: M_PPP
 *
 * RETURNS: mppp of other end, or NULL
 */

M_PPP
pl_otherend(M_PPP mppp)
{
   int   index;

   /* passed line MUST be connected */
   if(mppp->line.ln_state != LN_CONNECTED)
   {
      return NULL;
   }

   index = pl_lookup(mppp);
   if(index < 0)
   {
      dtrap("ppp_loop 0\n");
      return NULL;
   }
   return lb_otherend[index];
}


/* FUNCTION: pl_init()
 *
 * "init" routine for loopback driver.
 *
 * PARAM1: struct com_line * lineptr
 *
 * RETURNS: 0 if OK or ENP error code 
 */

int
pl_init(LINEP lineptr)
{
   M_PPP    mppp;
   int      free;    /* first free entry in table */
   int      i;

   mppp = (M_PPP)(lineptr->upper_unit);
   free = -1;
   for(i = 0; i < MAX_LBXOVERS; i++)
   {
      /* If this mppp has already been added then just return */
      if(lb_mppps[i] == mppp)
      {
         dtrap("ppp_loop 1\n");    /* sloppy progamming? */
         return ENP_LOGIC;
      }
      /* remember first free table entry */
      if((lb_mppps[i] == NULL) && (free < 0))
         free = i;
   }

   if(free < 0)   /* No free entry found? */
      return ENP_RESOURCE;

   lb_mppps[free] = mppp;
   lb_otherend[free] = NULL;     /* cleanup... */
   mppp->line.ln_state = LN_DISCONNECTED;

   return 0;
}


/* FUNCTION: pl_connect()
 *
 * Comm line "connect" routine for loopback driver.
 *
 * PARAM1: int unit
 * PARAM2: struct com_line * lineptr
 *
 * RETURNS: LN_CONNECTED if OK, else LN_DISCONNECTED
 */

int
pl_connect(LINEP line)
{
   int      client_index;
   int      server_index;
   M_PPP    server;
   M_PPP    client = (M_PPP)(line->upper_unit);

   /* find a free loopback link to be server for the new connection */
   server = NULL;
   for(server_index = 0; server_index < MAX_LBXOVERS; server_index++)
   {
      if(lb_mppps[server_index] == NULL)     /* skip empty entries */
         continue;
      if(lb_mppps[server_index] == client)   /* skip self (client) */
         continue;
      if(lb_mppps[server_index]->ifp == client->ifp)   /* skip same iface */
         continue;
      if(lb_mppps[server_index]->line.ln_state == LN_DISCONNECTED)
      {
         server = lb_mppps[server_index];
         break;
      }
   }
   if(server == NULL)
   {
      //ConPrintf("lbxover: no server\n");
      return LN_DISCONNECTED;
   }

   client_index = pl_lookup(client);
   if(client_index < 0)
   {
      //ConPrintf("lbxover: no client index\n");
      return LN_DISCONNECTED;
   }

   /* map the client and server links to each other */
   lb_otherend[client_index] = server;
   lb_otherend[server_index] = client;

   /* since there is no actual hardware to connect, the client is
    * logically up & connected at this point. 
    */
   line->ln_state = LN_CONNECTED;

   /* Signal the server line that it's lower level just came up. */
   server->line.ln_state = LN_CONNECTED;   /* server is now connected too */
   ppp_lowerup(server, LCP_STATE);
   ppp_open(server, LCP_STATE);

   ppp_lowerup(client, LCP_STATE);   /* Do client lowerup */

   return LN_CONNECTED;
}


/* FUNCTION: pl_hangup()
 *
 * disconnect the line
 * 
 * PARAM1: int unit
 *
 * RETURNS: 
 */

int
pl_hangup(LINEP line)
{
   int   index;
   M_PPP other_ppp;
   M_PPP mppp = (M_PPP)(line->upper_unit);

   /* if connected, hangup other unit gracfully */
   other_ppp = pl_otherend(mppp);
   if(other_ppp)
   {
      ppp_lowerdown(other_ppp, LCP_STATE);
      index = pl_lookup(mppp);
      lb_otherend[index] = NULL;    /* clear our partner entry */
   }

   /* No actual hardware; just set state */
   line->ln_state = LN_DISCONNECTED;

   return 0;
}



/* FUNCTION: pl_putc()
 * 
 * PARAM1: int unit
 * PARAM2: int byte
 *
 * RETURNS: 
 */

#ifdef PPP_CHARIO

int
pl_putc(LINEP line, int byte)
{
   M_PPP rxmp;    /* receiveing link */
   M_PPP txmp = (M_PPP)(line->upper_unit);   /* sending link */

   rxmp = pl_otherend(txmp);
   if(!rxmp)
   {
      dtrap("ppp_loop 2\n");    /* line is not a loopback line */
      return -1;
   }

   /* since xover lines are always working, check RX line's logical state */
   if(rxmp->line.ln_state != LN_CONNECTED)
   {
      dtrap("ppp_loop 3\n");
   }

   ppp_inchar(rxmp, byte);

   return 0;
}
#endif   /* PPP_CHARIO */


/* FUNCTION: pl_write()
 * 
 * PARAM1: int unit
 * PARAM2: char * block
 * PARAM3: int length
 *
 * RETURNS: 
 */

#ifdef PPP_PACKETS

int
pl_write(LINEP line, PACKET pkt)
{
   M_PPP rxmp;
   M_PPP txmp = (M_PPP)(line->upper_unit);

   rxmp = pl_otherend(txmp);
   if(!rxmp)
   {
      dtrap("ppp_loop 4\n");     /* bad mppp */
      return -1;
   }

   /* since xover lines are always working, check RX line's logical state */
   if(rxmp->line.ln_state != LN_CONNECTED)
   {
      dtrap("ppp_loop 5\n");
   }

   pkt->net = rxmp->ifp;		/* tag packet for receive network */
   putq(&ppp_rcvdq, (qp)pkt);	/* put pkt in input queue */
   SignalPPPDemux();			   /* wake demuxer */

   return 0;
}
#endif  /* PPP_PACKETS */


/* FUNCTION: ppp_lb_add_routes()
 *
 * Add static routes in the IP Route table for rthe first two static  
 * xover ifaces, This pings through PPP in CrossOver mode work without
 * the user having to manually configure routes. Find the two PPP 
 * interfaces and add routes for them. ip_init() in ip_startup() 
 * initializes the routing table. Hence the routes can only be added 
 * after ip_init(). Hence ppp_lb_add_routes() is called after 
 * ip_init() in ip_startup(). Returns 0 if OK, else error code of 
 * first error encountered. 
 *
 * 
 * PARAM1: void
 *
 * RETURNS: 0 if OK, else negative error  code.
 */

int
ppp_lb_add_routes(void)
{
   void *   rtp;     /* result of add_route() */
   int      iface;   /* scratch iface index */
   M_PPP    mp1;
   M_PPP    mp2;

   /* first see of we can find two of these lines */
   mp1 = NULL;
   for(mp2 = ppp_list; mp2; mp2 = mp2->next)
   {
      if(mp2->line.lower_type == LN_LBXOVER)
      {
         if(mp1 == NULL)/* is this first line found? */
            mp1 = mp2;  /* yes, set it */
         else           /* else mp1 is already set */
            break;      /* exit loop with mp2 as second line */
      }
   }
   if(!mp2)    /* didn't fiond two lines? */
      return ENP_LOGIC;

   /* add route to second IP through first iface */
   iface = if_netnumber(mp1->ifp);
   rtp = add_route(mp2->ifp->n_ipaddr, 0xFFFFFFFF, 
      mp2->ifp->n_ipaddr, iface, IPRP_LOCAL);
   if (!rtp)
   {
      dprintf("add_route failed, table full?\n");
      return -1;
   }

   /* Now add the route to first IP through second iface */
   iface = if_netnumber(mp2->ifp);
   rtp = add_route(mp1->ifp->n_ipaddr, 0xFFFFFFFF, 
      mp1->ifp->n_ipaddr, iface, IPRP_LOCAL);
   if (!rtp)
   {
      dprintf("add_route failed, table full?\n");
      return -1;
   }
   return 0;
}


/* end of file -  ppp_loop.c */
#endif   /* LB_XOVER */
#endif   /* USE_PPP */