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 <asm/atomic.h>
26
27 struct ppp_channel;
28
29 struct 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 };
37
38 struct ppp_channel {
39 void *private; /* channel private data */
40 struct ppp_channel_ops *ops; /* operations for this channel */
41 int mtu; /* max transmit packet size */
42 int hdrlen; /* amount of headroom channel needs */
43 void *ppp; /* opaque to channel */
44 /* the following are not used at present */
45 int speed; /* transfer rate (bytes/second) */
46 int latency; /* overhead time in milliseconds */
47 };
48
49 #ifdef __KERNEL__
50 /* Called by the channel when it can send some more data. */
51 extern void ppp_output_wakeup(struct ppp_channel *);
52
53 /* Called by the channel to process a received PPP packet.
54 The packet should have just the 2-byte PPP protocol header. */
55 extern void ppp_input(struct ppp_channel *, struct sk_buff *);
56
57 /* Called by the channel when an input error occurs, indicating
58 that we may have missed a packet. */
59 extern void ppp_input_error(struct ppp_channel *, int code);
60
61 /* Attach a channel to a given PPP unit. */
62 extern int ppp_register_channel(struct ppp_channel *);
63
64 /* Detach a channel from its PPP unit (e.g. on hangup). */
65 extern void ppp_unregister_channel(struct ppp_channel *);
66
67 /* Get the channel number for a channel */
68 extern int ppp_channel_index(struct ppp_channel *);
69
70 /* Get the unit number associated with a channel, or -1 if none */
71 extern int ppp_unit_number(struct ppp_channel *);
72
73 /*
74 * SMP locking notes:
75 * The channel code must ensure that when it calls ppp_unregister_channel,
76 * nothing is executing in any of the procedures above, for that
77 * channel. The generic layer will ensure that nothing is executing
78 * in the start_xmit and ioctl routines for the channel by the time
79 * that ppp_unregister_channel returns.
80 */
81
82 /* The following are temporary compatibility stuff */
83 ssize_t ppp_channel_read(struct ppp_channel *chan, struct file *file,
84 char *buf, size_t count);
85 ssize_t ppp_channel_write(struct ppp_channel *chan, const char *buf,
86 size_t count);
87 unsigned int ppp_channel_poll(struct ppp_channel *chan, struct file *file,
88 poll_table *wait);
89 int ppp_channel_ioctl(struct ppp_channel *chan, unsigned int cmd,
90 unsigned long arg);
91
92 #endif /* __KERNEL__ */
93 #endif
94
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