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 26 struct ppp_channel; 27 28 struct ppp_channel_ops { 29 /* Send a packet (or multilink fragment) on this channel. 30 Returns 1 if it was accepted, 0 if not. */ 31 int (*start_xmit)(struct ppp_channel *, struct sk_buff *); 32 /* Handle an ioctl call that has come in via /dev/ppp. */ 33 int (*ioctl)(struct ppp_channel *, unsigned int, unsigned long); 34 }; 35 36 struct ppp_channel { 37 void *private; /* channel private data */ 38 struct ppp_channel_ops *ops; /* operations for this channel */ 39 int mtu; /* max transmit packet size */ 40 int hdrlen; /* amount of headroom channel needs */ 41 void *ppp; /* opaque to channel */ 42 /* the following are not used at present */ 43 int speed; /* transfer rate (bytes/second) */ 44 int latency; /* overhead time in milliseconds */ 45 }; 46 47 #ifdef __KERNEL__ 48 /* Called by the channel when it can send some more data. */ 49 extern void ppp_output_wakeup(struct ppp_channel *); 50 51 /* Called by the channel to process a received PPP packet. 52 The packet should have just the 2-byte PPP protocol header. */ 53 extern void ppp_input(struct ppp_channel *, struct sk_buff *); 54 55 /* Called by the channel when an input error occurs, indicating 56 that we may have missed a packet. */ 57 extern void ppp_input_error(struct ppp_channel *, int code); 58 59 /* Attach a channel to a given PPP unit. */ 60 extern int ppp_register_channel(struct ppp_channel *); 61 62 /* Detach a channel from its PPP unit (e.g. on hangup). */ 63 extern void ppp_unregister_channel(struct ppp_channel *); 64 65 /* Get the channel number for a channel */ 66 extern int ppp_channel_index(struct ppp_channel *); 67 68 /* Get the unit number associated with a channel, or -1 if none */ 69 extern int ppp_unit_number(struct ppp_channel *); 70 71 /* 72 * SMP locking notes: 73 * The channel code must ensure that when it calls ppp_unregister_channel, 74 * nothing is executing in any of the procedures above, for that 75 * channel. The generic layer will ensure that nothing is executing 76 * in the start_xmit and ioctl routines for the channel by the time 77 * that ppp_unregister_channel returns. 78 */ 79 80 #endif /* __KERNEL__ */ 81 #endif 82