ax25.h File Reference

Simple AX25 data link layer implementation. More...

#include "cfg/cfg_ax25.h"
#include <cfg/compiler.h>
#include <kern/kfile.h>

Go to the source code of this file.

Data Structures
struct	AX25Ctx
	AX25 Protocol context. More...
struct	AX25Call
	AX25 Call sign. More...
struct	AX25Msg
	AX25 Message. More...
Defines
#define	AX25_MIN_FRAME_LEN   18
	Maximum size of a AX25 frame.
#define	AX25_CRC_CORRECT   0xF0B8
	CRC computation on correct AX25 packets should give this result (don't ask why).
#define	AX25_CALL(str, id)   ({ static const AX25Call _call = { .call = (str), .ssid = (id) }; &_call; })
	Create an AX25Call structure on the fly and return its pointer.
#define	AX25_MAX_RPT   8
	Maximum number of Repeaters in a AX25 message.
HDLC flags.
These should be moved in a separated HDLC related file one day. ..
#define	HDLC_FLAG   0x7E
#define	HDLC_RESET   0x7F
#define	AX25_ESC   0x1B
Typedefs
typedef void(*	ax25_callback_t )(struct AX25Msg *msg)
	Type for AX25 messages callback.
Functions
void	ax25_poll (AX25Ctx *ctx)
	Check if there are any AX25 messages to be processed.
void	ax25_send (AX25Ctx *ctx, const AX25Call *dst, const AX25Call *src, const void *_buf, size_t len)
	Send an AX25 frame on the channel.
void	ax25_init (AX25Ctx *ctx, KFile *channel, ax25_callback_t hook)
	Init the AX25 protocol decoder.

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Detailed Description

Simple AX25 data link layer implementation.

For now, only UI frames without any Layer 3 protocol are handled. This however is enough to send/receive APRS packets.

Version:

$Id$

Author:

Francesco Sacchi <batt@develer.com>

Definition in file ax25.h.

---

Define Documentation

#define AX25_CALL	(	str,
		id		)	({ static const AX25Call _call = { .call = (str), .ssid = (id) }; &_call; })

Create an AX25Call structure on the fly and return its pointer.

Parameters:

	str	callsign, can be 6 characters or shorter.
	id	ssid associated with the callsign.

Definition at line 103 of file ax25.h.

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Function Documentation

void ax25_init	(	AX25Ctx *	ctx,
		KFile *	channel,
		ax25_callback_t	hook
	)

Init the AX25 protocol decoder.

Parameters:

	ctx	AX25 context to init.
	channel	Used to gain access to the physical medium
	hook	Callback function called when a message is received

Definition at line 264 of file ax25.c.

void ax25_poll

(

AX25Ctx *

ctx

)

Check if there are any AX25 messages to be processed.

This function read available characters from the medium and search for any AX25 messages. If a message is found it is decoded and the linked callback executed. This function may be blocking if there are no available chars and the KFile used in ctx to access the medium is configured in blocking mode.

Parameters:

ctx

AX25 context to operate on.

Definition at line 125 of file ax25.c.

void ax25_send	(	AX25Ctx *	ctx,
		const AX25Call *	dst,
		const AX25Call *	src,
		const void *	_buf,
		size_t	len
	)

Send an AX25 frame on the channel.

Parameters:

	ctx	AX25 context to operate on.
	dst	the destination callsign for the frame,

See also:

AX25_CALL for a handy way to create a callsign on the fly.

Parameters:

src

the source callsign for the frame,

See also:

AX25_CALL for a handy way to create a callsign on the fly.

Parameters:

	_buf	payload buffer.
	len	length of the payload.

Definition at line 224 of file ax25.c.