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