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 ppp_channel; 24 25 struct ppp_channel_ops { 26 /* Send a packet (or multilink fragment) on this channel. 27 Returns 1 if it was accepted, 0 if not. */ 28 int (*start_xmit)(struct ppp_channel *, struct sk_buff *); 29 /* Handle an ioctl call that has come in via /dev/ppp. */ 30 int (*ioctl)(struct ppp_channel *, unsigned int, unsigned long); 31 }; 32 33 struct ppp_channel { 34 void *private; /* channel private data */ 35 const struct ppp_channel_ops *ops; /* operations for this channel */ 36 int mtu; /* max transmit packet size */ 37 int hdrlen; /* amount of headroom channel needs */ 38 void *ppp; /* opaque to channel */ 39 int speed; /* transfer rate (bytes/second) */ 40 /* the following is not used at present */ 41 int latency; /* overhead time in milliseconds */ 42 }; 43 44 #ifdef __KERNEL__ 45 /* Called by the channel when it can send some more data. */ 46 extern void ppp_output_wakeup(struct ppp_channel *); 47 48 /* Called by the channel to process a received PPP packet. 49 The packet should have just the 2-byte PPP protocol header. */ 50 extern void ppp_input(struct ppp_channel *, struct sk_buff *); 51 52 /* Called by the channel when an input error occurs, indicating 53 that we may have missed a packet. */ 54 extern void ppp_input_error(struct ppp_channel *, int code); 55 56 /* Attach a channel to a given PPP unit in specified net. */ 57 extern int ppp_register_net_channel(struct net *, struct ppp_channel *); 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 /* Get the device name associated with a channel, or NULL if none */ 72 extern char *ppp_dev_name(struct ppp_channel *); 73 74 /* 75 * SMP locking notes: 76 * The channel code must ensure that when it calls ppp_unregister_channel, 77 * nothing is executing in any of the procedures above, for that 78 * channel. The generic layer will ensure that nothing is executing 79 * in the start_xmit and ioctl routines for the channel by the time 80 * that ppp_unregister_channel returns. 81 */ 82 83 #endif /* __KERNEL__ */ 84 #endif 85