--- /dev/null
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2009 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ * \brief 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>
+ *
+ * $WIZ$ module_name = "ax25"
+ * $WIZ$ module_configuration = "bertos/cfg/cfg_ax25.h"
+ * $WIZ$ module_depends = "kfile"
+ */
+
+
+#ifndef NET_AX25_H
+#define NET_AX25_H
+
+#include "cfg/cfg_ax25.h"
+
+#include <cfg/compiler.h>
+#include <kern/kfile.h>
+
+/**
+ * Maximum size of a AX25 frame.
+ */
+#define AX25_MIN_FRAME_LEN 18
+
+/**
+ * CRC computation on correct AX25 packets should
+ * give this result (don't ask why).
+ */
+#define AX25_CRC_CORRECT 0xF0B8
+
+struct AX25Msg; // fwd declaration
+
+/**
+ * Type for AX25 messages callback.
+ */
+typedef void (*ax25_callback_t)(struct AX25Msg *msg);
+
+
+/**
+ * AX25 Protocol context.
+ */
+typedef struct AX25Ctx
+{
+ uint8_t buf[CONFIG_AX25_FRAME_BUF_LEN]; ///< buffer for received chars
+ KFile *ch; ///< KFile used to access the physical medium
+ size_t frm_len; ///< received frame length.
+ uint16_t crc_in; ///< CRC for current received frame
+ uint16_t crc_out; ///< CRC of current sent frame
+ ax25_callback_t hook; ///< Hook function to be called when a message is received
+ bool sync; ///< True if we have received a HDLC flag.
+ bool escape; ///< True when we have to escape the following char.
+} AX25Ctx;
+
+
+/**
+ * AX25 Call sign.
+ */
+typedef struct AX25Call
+{
+ char call[6]; ///< Call string, max 6 character
+ uint8_t ssid; ///< SSID (secondary station ID) for the call
+} AX25Call;
+
+/**
+ * Maximum number of Repeaters in a AX25 message.
+ */
+#define AX25_MAX_RPT 8
+
+
+/**
+ * AX25 Message.
+ * Used to handle AX25 sent/received messages.
+ */
+typedef struct AX25Msg
+{
+ AX25Call src; ///< Source adress
+ AX25Call dst; ///< Destination address
+ #if CONFIG_AX25_RPT_LST
+ AX25Call rpt_lst[AX25_MAX_RPT]; ///< List of repeaters
+ uint8_t rpt_cnt; ///< Number of repeaters in this message
+ #endif
+ uint16_t ctrl; ///< AX25 control field
+ uint8_t pid; ///< AX25 PID field
+ uint8_t *info; ///< Pointer to the info field (payload) of the message
+ size_t len; ///< Payload length
+} AX25Msg;
+
+#define AX25_CTRL_UI 0x03
+#define AX25_PID_NOLAYER3 0xF0
+
+/**
+ * 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
+/* \} */
+
+
+/**
+ * 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 \a ctx to access the medium is configured in blocking mode.
+ *
+ * \param ctx AX25 context to operate on.
+ */
+void ax25_poll(AX25Ctx *ctx);
+
+/**
+ * Init the AX25 protocol decoder.
+ *
+ * \param ctx AX25 context to init.
+ * \param channel Used to gain access to the physical medium
+ * \param hook Callback function called when a message is received
+ */
+void ax25_init(AX25Ctx *ctx, KFile *channel, ax25_callback_t hook);
+
+#endif /* NET_AX25_H */
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