154 lines
5.1 KiB
C
154 lines
5.1 KiB
C
/*
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* FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
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* Copyright (C) 2009, Steve Underwood <steveu@coppice.org>
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*
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* Version: MPL 1.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* Contributor(s):
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*
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* Steve Underwood <steveu@coppice.org>
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*
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* udptl.h -- UDPTL handling for T.38
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*
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*/
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#if !defined(FREESWITCH_UDPTL_H)
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#define FREESWITCH_UDPTL_H
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#define LOCAL_FAX_MAX_DATAGRAM 400
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#define LOCAL_FAX_MAX_FEC_PACKETS 5
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#define UDPTL_BUF_MASK 15
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typedef int (udptl_rx_packet_handler_t) (void *user_data, const uint8_t msg[], int len, int seq_no);
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typedef struct {
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int buf_len;
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uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
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} udptl_fec_tx_buffer_t;
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typedef struct {
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int buf_len;
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uint8_t buf[LOCAL_FAX_MAX_DATAGRAM];
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int fec_len[LOCAL_FAX_MAX_FEC_PACKETS];
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uint8_t fec[LOCAL_FAX_MAX_FEC_PACKETS][LOCAL_FAX_MAX_DATAGRAM];
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int fec_span;
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int fec_entries;
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} udptl_fec_rx_buffer_t;
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struct udptl_state_s {
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udptl_rx_packet_handler_t *rx_packet_handler;
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void *user_data;
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/*! This option indicates the error correction scheme used in transmitted UDPTL
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packets. */
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int error_correction_scheme;
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/*! This option indicates the number of error correction entries transmitted in
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UDPTL packets. */
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int error_correction_entries;
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/*! This option indicates the span of the error correction entries in transmitted
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UDPTL packets (FEC only). */
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int error_correction_span;
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/*! This option indicates the maximum size of a datagram that can be accepted by
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the remote device. */
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int far_max_datagram_size;
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/*! This option indicates the maximum size of a datagram that we are prepared to
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accept. */
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int local_max_datagram_size;
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int verbose;
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int tx_seq_no;
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int rx_seq_no;
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int rx_expected_seq_no;
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udptl_fec_tx_buffer_t tx[UDPTL_BUF_MASK + 1];
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udptl_fec_rx_buffer_t rx[UDPTL_BUF_MASK + 1];
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};
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enum {
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UDPTL_ERROR_CORRECTION_NONE,
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UDPTL_ERROR_CORRECTION_FEC,
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UDPTL_ERROR_CORRECTION_REDUNDANCY
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};
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typedef struct udptl_state_s udptl_state_t;
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/*! \brief Process an arriving UDPTL packet.
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\param s The UDPTL context.
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\param buf The UDPTL packet buffer.
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\param len The length of the packet.
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\return 0 for OK. */
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int udptl_rx_packet(udptl_state_t *s, const uint8_t buf[], int len);
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/*! \brief Construct a UDPTL packet, ready for transmission.
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\param s The UDPTL context.
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\param buf The UDPTL packet buffer.
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\param msg The primary packet.
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\param len The length of the primary packet.
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\return The length of the constructed UDPTL packet. */
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int udptl_build_packet(udptl_state_t *s, uint8_t buf[], const uint8_t msg[], int msg_len);
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/*! \brief Change the error correction settings of a UDPTL context.
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\param s The UDPTL context.
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\param ec_scheme One of the optional error correction schemes.
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\param span The packet span over which error correction should be applied.
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\param entries The number of error correction entries to include in packets.
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\return 0 for OK. */
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int udptl_set_error_correction(udptl_state_t *s, int ec_scheme, int span, int entries);
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/*! \brief Check the error correction settings of a UDPTL context.
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\param s The UDPTL context.
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\param ec_scheme One of the optional error correction schemes.
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\param span The packet span over which error correction is being applied.
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\param entries The number of error correction being included in packets.
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\return 0 for OK. */
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int udptl_get_error_correction(udptl_state_t *s, int *ec_scheme, int *span, int *entries);
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int udptl_set_local_max_datagram(udptl_state_t *s, int max_datagram);
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int udptl_get_local_max_datagram(udptl_state_t *s);
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int udptl_set_far_max_datagram(udptl_state_t *s, int max_datagram);
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int udptl_get_far_max_datagram(udptl_state_t *s);
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/*! \brief Initialise a UDPTL context.
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\param s The UDPTL context.
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\param ec_scheme One of the optional error correction schemes.
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\param span The packet span over which error correction should be applied.
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\param entries The number of error correction entries to include in packets.
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\param rx_packet_handler The callback function, used to report arriving IFP packets.
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\param user_data An opaque pointer supplied to rx_packet_handler.
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\return A pointer to the UDPTL context, or NULL if there was a problem. */
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udptl_state_t *udptl_init(udptl_state_t *s, int ec_scheme, int span, int entries, udptl_rx_packet_handler_t rx_packet_handler, void *user_data);
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/*! \brief Release a UDPTL context.
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\param s The UDPTL context.
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\return 0 for OK. */
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int udptl_release(udptl_state_t *s);
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/*- End of file ------------------------------------------------------------*/
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