1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2 | #ifndef _PPP_CHANNEL_H_ |
3 | #define _PPP_CHANNEL_H_ |
4 | /* |
5 | * Definitions for the interface between the generic PPP code |
6 | * and a PPP channel. |
7 | * |
8 | * A PPP channel provides a way for the generic PPP code to send |
9 | * and receive packets over some sort of communications medium. |
10 | * Packets are stored in sk_buffs and have the 2-byte PPP protocol |
11 | * number at the start, but not the address and control bytes. |
12 | * |
13 | * Copyright 1999 Paul Mackerras. |
14 | * |
15 | * ==FILEVERSION 20000322== |
16 | */ |
17 | |
18 | #include <linux/list.h> |
19 | #include <linux/skbuff.h> |
20 | #include <linux/poll.h> |
21 | #include <net/net_namespace.h> |
22 | |
23 | struct net_device_path; |
24 | struct net_device_path_ctx; |
25 | struct ppp_channel; |
26 | |
27 | struct ppp_channel_ops { |
28 | /* Send a packet (or multilink fragment) on this channel. |
29 | Returns 1 if it was accepted, 0 if not. */ |
30 | int (*start_xmit)(struct ppp_channel *, struct sk_buff *); |
31 | /* Handle an ioctl call that has come in via /dev/ppp. */ |
32 | int (*ioctl)(struct ppp_channel *, unsigned int, unsigned long); |
33 | int (*fill_forward_path)(struct net_device_path_ctx *, |
34 | struct net_device_path *, |
35 | const struct ppp_channel *); |
36 | }; |
37 | |
38 | struct ppp_channel { |
39 | void *private; /* channel private data */ |
40 | const 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 | int speed; /* transfer rate (bytes/second) */ |
45 | /* the following is not used at present */ |
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 in specified net. */ |
62 | extern int ppp_register_net_channel(struct net *, struct ppp_channel *); |
63 | |
64 | /* Attach a channel to a given PPP unit. */ |
65 | extern int ppp_register_channel(struct ppp_channel *); |
66 | |
67 | /* Detach a channel from its PPP unit (e.g. on hangup). */ |
68 | extern void ppp_unregister_channel(struct ppp_channel *); |
69 | |
70 | /* Get the channel number for a channel */ |
71 | extern int ppp_channel_index(struct ppp_channel *); |
72 | |
73 | /* Get the unit number associated with a channel, or -1 if none */ |
74 | extern int ppp_unit_number(struct ppp_channel *); |
75 | |
76 | /* Get the device name associated with a channel, or NULL if none */ |
77 | extern char *ppp_dev_name(struct ppp_channel *); |
78 | |
79 | /* |
80 | * SMP locking notes: |
81 | * The channel code must ensure that when it calls ppp_unregister_channel, |
82 | * nothing is executing in any of the procedures above, for that |
83 | * channel. The generic layer will ensure that nothing is executing |
84 | * in the start_xmit and ioctl routines for the channel by the time |
85 | * that ppp_unregister_channel returns. |
86 | */ |
87 | |
88 | #endif /* __KERNEL__ */ |
89 | #endif |
90 | |