LXR linux/include/linux/ppp

   1#ifndef _PPP_CHANNEL_H_
   2#define _PPP_CHANNEL_H_
   3/*
   4 * Definitions for the interface between the generic PPP code
   5 * and a PPP channel.
   6 *
   7 * A PPP channel provides a way for the generic PPP code to send
   8 * and receive packets over some sort of communications medium.
   9 * Packets are stored in sk_buffs and have the 2-byte PPP protocol
  10 * number at the start, but not the address and control bytes.
  11 *
  12 * Copyright 1999 Paul Mackerras.
  13 *
  14 *  This program is free software; you can redistribute it and/or
  15 *  modify it under the terms of the GNU General Public License
  16 *  as published by the Free Software Foundation; either version
  17 *  2 of the License, or (at your option) any later version.
  18 *
  19 * ==FILEVERSION 20000322==
  20 */
  21
  22#include <linux/list.h>
  23#include <linux/skbuff.h>
  24#include <linux/poll.h>
  25#include <net/net_namespace.h>
  26
  27struct ppp_channel;
  28
  29struct ppp_channel_ops {
  30        /* Send a packet (or multilink fragment) on this channel.
  31           Returns 1 if it was accepted, 0 if not. */
  32        int     (*start_xmit)(struct ppp_channel *, struct sk_buff *);
  33        /* Handle an ioctl call that has come in via /dev/ppp. */
  34        int     (*ioctl)(struct ppp_channel *, unsigned int, unsigned long);
  35};
  36
  37struct ppp_channel {
  38        void            *private;       /* channel private data */
  39        const struct ppp_channel_ops *ops; /* operations for this channel */
  40        int             mtu;            /* max transmit packet size */
  41        int             hdrlen;         /* amount of headroom channel needs */
  42        void            *ppp;           /* opaque to channel */
  43        int             speed;          /* transfer rate (bytes/second) */
  44        /* the following is not used at present */
  45        int             latency;        /* overhead time in milliseconds */
  46};
  47
  48#ifdef __KERNEL__
  49/* Called by the channel when it can send some more data. */
  50extern void ppp_output_wakeup(struct ppp_channel *);
  51
  52/* Called by the channel to process a received PPP packet.
  53   The packet should have just the 2-byte PPP protocol header. */
  54extern void ppp_input(struct ppp_channel *, struct sk_buff *);
  55
  56/* Called by the channel when an input error occurs, indicating
  57   that we may have missed a packet. */
  58extern void ppp_input_error(struct ppp_channel *, int code);
  59
  60/* Attach a channel to a given PPP unit in specified net. */
  61extern int ppp_register_net_channel(struct net *, struct ppp_channel *);
  62
  63/* Attach a channel to a given PPP unit. */
  64extern int ppp_register_channel(struct ppp_channel *);
  65
  66/* Detach a channel from its PPP unit (e.g. on hangup). */
  67extern void ppp_unregister_channel(struct ppp_channel *);
  68
  69/* Get the channel number for a channel */
  70extern int ppp_channel_index(struct ppp_channel *);
  71
  72/* Get the unit number associated with a channel, or -1 if none */
  73extern int ppp_unit_number(struct ppp_channel *);
  74
  75/* Get the device name associated with a channel, or NULL if none */
  76extern char *ppp_dev_name(struct ppp_channel *);
  77
  78/*
  79 * SMP locking notes:
  80 * The channel code must ensure that when it calls ppp_unregister_channel,
  81 * nothing is executing in any of the procedures above, for that
  82 * channel.  The generic layer will ensure that nothing is executing
  83 * in the start_xmit and ioctl routines for the channel by the time
  84 * that ppp_unregister_channel returns.
  85 */
  86
  87#endif /* __KERNEL__ */
  88#endif
  89