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29 * Copyright 2009 Develer S.r.l. (http://www.develer.com/)
32 * \brief Simple AX25 data link layer implementation.
34 * For now, only UI frames without any Layer 3 protocol are handled.
35 * This however is enough to send/receive APRS packets.
38 * \author Francesco Sacchi <batt@develer.com>
40 * $WIZ$ module_name = "ax25"
41 * $WIZ$ module_configuration = "bertos/cfg/cfg_ax25.h"
42 * $WIZ$ module_depends = "kfile", "crc-ccitt"
49 #include "cfg/cfg_ax25.h"
51 #include <cfg/compiler.h>
52 #include <kern/kfile.h>
55 * Maximum size of a AX25 frame.
57 #define AX25_MIN_FRAME_LEN 18
60 * CRC computation on correct AX25 packets should
61 * give this result (don't ask why).
63 #define AX25_CRC_CORRECT 0xF0B8
65 struct AX25Msg; // fwd declaration
68 * Type for AX25 messages callback.
70 typedef void (*ax25_callback_t)(struct AX25Msg *msg);
74 * AX25 Protocol context.
76 typedef struct AX25Ctx
78 uint8_t buf[CONFIG_AX25_FRAME_BUF_LEN]; ///< buffer for received chars
79 KFile *ch; ///< KFile used to access the physical medium
80 size_t frm_len; ///< received frame length.
81 uint16_t crc_in; ///< CRC for current received frame
82 uint16_t crc_out; ///< CRC of current sent frame
83 ax25_callback_t hook; ///< Hook function to be called when a message is received
84 bool sync; ///< True if we have received a HDLC flag.
85 bool escape; ///< True when we have to escape the following char.
92 typedef struct AX25Call
94 char call[6]; ///< Call string, max 6 character
95 uint8_t ssid; ///< SSID (secondary station ID) for the call
99 * Create an AX25Call structure on the fly and return its pointer.
100 * \param str callsign, can be 6 characters or shorter.
101 * \param id ssid associated with the callsign.
103 #define AX25_CALL(str, id) ({ static const AX25Call _call = { .call = (str), .ssid = (id) }; &_call; })
106 * Maximum number of Repeaters in a AX25 message.
108 #define AX25_MAX_RPT 8
113 * Used to handle AX25 sent/received messages.
115 typedef struct AX25Msg
117 AX25Call src; ///< Source adress
118 AX25Call dst; ///< Destination address
119 #if CONFIG_AX25_RPT_LST
120 AX25Call rpt_lst[AX25_MAX_RPT]; ///< List of repeaters
121 uint8_t rpt_cnt; ///< Number of repeaters in this message
123 uint16_t ctrl; ///< AX25 control field
124 uint8_t pid; ///< AX25 PID field
125 const uint8_t *info; ///< Pointer to the info field (payload) of the message
126 size_t len; ///< Payload length
129 #define AX25_CTRL_UI 0x03
130 #define AX25_PID_NOLAYER3 0xF0
134 * These should be moved in
135 * a separated HDLC related file one day...
138 #define HDLC_FLAG 0x7E
139 #define HDLC_RESET 0x7F
140 #define AX25_ESC 0x1B
145 void ax25_poll(AX25Ctx *ctx);
146 void ax25_send(AX25Ctx *ctx, const AX25Call *dst, const AX25Call *src, const void *_buf, size_t len);
147 void ax25_init(AX25Ctx *ctx, KFile *channel, ax25_callback_t hook);
149 int ax25_testSetup(void);
150 int ax25_testTearDown(void);
151 int ax25_testRun(void);
153 #endif /* NET_AX25_H */