lws-transport-sequencer.h

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/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2026 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#if !defined(__LWS_TRANSPORT_SEQUENCER_H__)
#define __LWS_TRANSPORT_SEQUENCER_H__
 
#include <stdint.h>
#include <stddef.h>
 
#if defined(LWS_WITH_TRANSPORT_SEQUENCER)
 

 
struct lws_transport_sequencer;
 
typedef int (*lws_transport_sequencer_cb_t)(struct lws_transport_sequencer *ts,
                                            uint64_t offset, uint8_t *buf,
                                            size_t *len);
 
typedef struct lws_transport_sequencer_sack_block {
        uint64_t        start;
        uint32_t        len;
} lws_transport_sequencer_sack_block_t;
 
/*
 * Lifetime: tx_chunk and tx_ack are called in the middle of the sequencer's
 * work and must not destroy it.  on_rx_data and on_state_change are always
 * the last thing the sequencer does before returning to its caller, and it
 * does not touch ts after them, so they (or what they call) may destroy it.
 * A caller of lws_transport_sequencer_rx(), _acknowledge(), or
 * _acknowledge_sack() must not use ts after it returns, unless it knows its
 * callbacks did not destroy it.
 */
 
typedef struct lws_transport_sequencer_ops {
        const char *name;
 
        int (*tx_chunk)(struct lws_transport_sequencer *ts, uint64_t offset,
                        const uint8_t *buf, size_t len);
 
        int (*tx_ack)(struct lws_transport_sequencer *ts, uint64_t offset,
                      size_t len);
 
        int (*on_rx_data)(struct lws_transport_sequencer *ts, uint64_t offset,
                          const uint8_t *buf, size_t len);
 
        void (*on_state_change)(struct lws_transport_sequencer *ts, int state, int status);
 
        void (*on_writeable)(struct lws_transport_sequencer *ts);
 
} lws_transport_sequencer_ops_t;
 
typedef struct lws_transport_sequencer_stats {
        uint32_t        tx_packets;
        uint32_t        tx_retries;
        uint32_t        rx_packets;
        uint32_t        rx_duplicates;
        uint64_t        tx_bytes;
        uint64_t        rx_bytes;
        uint64_t        ack_offset;
        uint64_t        rx_offset;
        uint64_t        tx_offset;
} lws_transport_sequencer_stats_t;
 
typedef struct lws_transport_sequencer_info {
        struct lws_context *cx;
        const lws_transport_sequencer_ops_t *ops;
        const lws_retry_bo_t *retry_policy;
        void *user_data;
 
        uint32_t window_size;
 
        const char *peer;
 
        uint8_t unproven_peer:1;
} lws_transport_sequencer_info_t;

LWS_VISIBLE LWS_EXTERN struct lws_transport_sequencer *
lws_transport_sequencer_create(const lws_transport_sequencer_info_t *i);

LWS_VISIBLE LWS_EXTERN void
lws_transport_sequencer_destroy(struct lws_transport_sequencer **pts);

enum lws_transport_sequencer_write_result {
        LWS_TSW_QUEUED          = 0,
        LWS_TSW_FAILED          = 1,
        LWS_TSW_BUSY            = 2,
};

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_write(struct lws_transport_sequencer *ts,
                              const uint8_t *buf, size_t len);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_write_at(struct lws_transport_sequencer *ts,
                                 uint64_t offset, const uint8_t *buf, size_t len);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_acknowledge(struct lws_transport_sequencer *ts,
                                    uint64_t offset, size_t len, int status);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_acknowledge_sack(struct lws_transport_sequencer *ts,
                                         uint64_t cumulative_offset,
                                         const lws_transport_sequencer_sack_block_t *blocks,
                                         size_t num_blocks, int status);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_resend(struct lws_transport_sequencer *ts);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_tx_rebase(struct lws_transport_sequencer *ts);
 
LWS_VISIBLE LWS_EXTERN const lws_transport_sequencer_stats_t *
lws_transport_sequencer_get_stats(struct lws_transport_sequencer *ts);

LWS_VISIBLE LWS_EXTERN int
lws_transport_sequencer_rx(struct lws_transport_sequencer *ts,
                           uint64_t offset, const uint8_t *buf, size_t len);

LWS_VISIBLE LWS_EXTERN void
lws_transport_sequencer_rx_reset(struct lws_transport_sequencer *ts);

LWS_VISIBLE LWS_EXTERN size_t
lws_transport_sequencer_get_sack_blocks(struct lws_transport_sequencer *ts,
                                        lws_transport_sequencer_sack_block_t *blocks,
                                        size_t max_blocks);
 
LWS_VISIBLE LWS_EXTERN const lws_transport_sequencer_info_t *
lws_transport_sequencer_get_info(struct lws_transport_sequencer *ts);

 
#endif /* LWS_WITH_TRANSPORT_SEQUENCER */
 
#endif /* __LWS_TRANSPORT_SEQUENCER_H__ */