/*

 * Copyright 2022-2026 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "internal/quic_fifd.h"

#include "internal/quic_wire.h"

#include "internal/qlog_event_helpers.h"

DEFINE_LIST_OF(tx_history, OSSL_ACKM_TX_PKT);

int ossl_quic_fifd_init(QUIC_FIFD *fifd,

    QUIC_CFQ *cfq,

    OSSL_ACKM *ackm,

    QUIC_TXPIM *txpim,

    /* stream_id is UINT64_MAX for the crypto stream */

    QUIC_SSTREAM *(*get_sstream_by_id)(uint64_t stream_id,

        uint32_t pn_space,

        void *arg),

    void *get_sstream_by_id_arg,

    /* stream_id is UINT64_MAX if not applicable */

    void (*regen_frame)(uint64_t frame_type,

        uint64_t stream_id,

        QUIC_TXPIM_PKT *pkt,

        void *arg),

    void *regen_frame_arg,

    void (*confirm_frame)(uint64_t frame_type,

        uint64_t stream_id,

        QUIC_TXPIM_PKT *pkt,

        void *arg),

    void *confirm_frame_arg,

    void (*sstream_updated)(uint64_t stream_id,

        void *arg),

    void *sstream_updated_arg,

    QLOG *(*get_qlog_cb)(void *arg),

    void *get_qlog_cb_arg)

{

    if (cfq == NULL || ackm == NULL || txpim == NULL

        || get_sstream_by_id == NULL || regen_frame == NULL)

        return 0;

    fifd->cfq = cfq;

    fifd->ackm = ackm;

    fifd->txpim = txpim;

    fifd->get_sstream_by_id = get_sstream_by_id;

    fifd->get_sstream_by_id_arg = get_sstream_by_id_arg;

    fifd->regen_frame = regen_frame;

    fifd->regen_frame_arg = regen_frame_arg;

    fifd->confirm_frame = confirm_frame;

    fifd->confirm_frame_arg = confirm_frame_arg;

    fifd->sstream_updated = sstream_updated;

    fifd->sstream_updated_arg = sstream_updated_arg;

    fifd->get_qlog_cb = get_qlog_cb;

    fifd->get_qlog_cb_arg = get_qlog_cb_arg;

    return 1;

}

void ossl_quic_fifd_cleanup(QUIC_FIFD *fifd)

{

    /* No-op. */

}

static void on_acked(void *arg)

{

    QUIC_TXPIM_PKT *pkt = arg;

    QUIC_FIFD *fifd = pkt->fifd;

    const QUIC_TXPIM_CHUNK *chunks = ossl_quic_txpim_pkt_get_chunks(pkt);

    size_t i, num_chunks = ossl_quic_txpim_pkt_get_num_chunks(pkt);

    QUIC_SSTREAM *sstream;

    QUIC_CFQ_ITEM *cfq_item, *cfq_item_next;

    /* STREAM and CRYPTO stream chunks, FINs and stream FC frames */

    for (i = 0; i < num_chunks; ++i) {

        sstream = fifd->get_sstream_by_id(chunks[i].stream_id,

            pkt->ackm_pkt.pkt_space,

            fifd->get_sstream_by_id_arg);

        if (sstream == NULL)

            continue;

        if (chunks[i].end >= chunks[i].start)

            /* coverity[check_return]: Best effort - we cannot fail here. */

            ossl_quic_sstream_mark_acked(sstream,

                chunks[i].start, chunks[i].end);

        if (chunks[i].has_fin && chunks[i].stream_id != UINT64_MAX)

            ossl_quic_sstream_mark_acked_fin(sstream);

        if (chunks[i].has_stop_sending && chunks[i].stream_id != UINT64_MAX)

            fifd->confirm_frame(OSSL_QUIC_FRAME_TYPE_STOP_SENDING,

                chunks[i].stream_id, pkt,

                fifd->confirm_frame_arg);

        if (chunks[i].has_reset_stream && chunks[i].stream_id != UINT64_MAX)

            fifd->confirm_frame(OSSL_QUIC_FRAME_TYPE_RESET_STREAM,

                chunks[i].stream_id, pkt,

                fifd->confirm_frame_arg);

        if (ossl_quic_sstream_is_totally_acked(sstream))

            fifd->sstream_updated(chunks[i].stream_id, fifd->sstream_updated_arg);

    }

    /* GCR */

    for (cfq_item = pkt->retx_head; cfq_item != NULL; cfq_item = cfq_item_next) {

        cfq_item_next = cfq_item->pkt_next;

        ossl_quic_cfq_release(fifd->cfq, cfq_item);

    }

    ossl_quic_txpim_pkt_release(fifd->txpim, pkt);

}

static QLOG *fifd_get_qlog(QUIC_FIFD *fifd)

{

    if (fifd->get_qlog_cb == NULL)

        return NULL;

    return fifd->get_qlog_cb(fifd->get_qlog_cb_arg);

}

static void on_lost(void *arg)

{

    QUIC_TXPIM_PKT *pkt = arg;

    QUIC_FIFD *fifd = pkt->fifd;

    const QUIC_TXPIM_CHUNK *chunks = ossl_quic_txpim_pkt_get_chunks(pkt);

    size_t i, num_chunks = ossl_quic_txpim_pkt_get_num_chunks(pkt);

    QUIC_SSTREAM *sstream;

    QUIC_CFQ_ITEM *cfq_item, *cfq_item_next;

    int sstream_updated;

    ossl_qlog_event_recovery_packet_lost(fifd_get_qlog(fifd), pkt);

    /* STREAM and CRYPTO stream chunks, FIN and stream FC frames */

    for (i = 0; i < num_chunks; ++i) {

        sstream = fifd->get_sstream_by_id(chunks[i].stream_id,

            pkt->ackm_pkt.pkt_space,

            fifd->get_sstream_by_id_arg);

        if (sstream == NULL)

            continue;

        sstream_updated = 0;

        if (chunks[i].end >= chunks[i].start) {

            /*

             * Note: If the stream is being reset, we do not need to retransmit

             * old data as this is pointless. In this case this will be handled

             * by (sstream == NULL) above as the QSM will free the QUIC_SSTREAM

             * and our call to get_sstream_by_id above will return NULL.

             */

            ossl_quic_sstream_mark_lost(sstream,

                chunks[i].start, chunks[i].end);

            sstream_updated = 1;

        }

        if (chunks[i].has_fin && chunks[i].stream_id != UINT64_MAX) {

            ossl_quic_sstream_mark_lost_fin(sstream);

            sstream_updated = 1;

        }

        if (chunks[i].has_stop_sending && chunks[i].stream_id != UINT64_MAX)

            fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_STOP_SENDING,

                chunks[i].stream_id, pkt,

                fifd->regen_frame_arg);

        if (chunks[i].has_reset_stream && chunks[i].stream_id != UINT64_MAX)

            fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_RESET_STREAM,

                chunks[i].stream_id, pkt,

                fifd->regen_frame_arg);

        /*

         * Inform caller that stream needs an FC frame.

         *

         * Note: We could track whether an FC frame was sent originally for the

         * stream to determine if it really needs to be regenerated or not.

         * However, if loss has occurred, it's probably better to ensure the

         * peer has up-to-date flow control data for the stream. Given that

         * these frames are extremely small, we may as well always send it when

         * handling loss.

         */

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_MAX_STREAM_DATA,

            chunks[i].stream_id,

            pkt,

            fifd->regen_frame_arg);

        if (sstream_updated && chunks[i].stream_id != UINT64_MAX)

            fifd->sstream_updated(chunks[i].stream_id,

                fifd->sstream_updated_arg);

    }

    /* GCR */

    for (cfq_item = pkt->retx_head; cfq_item != NULL; cfq_item = cfq_item_next) {

        cfq_item_next = cfq_item->pkt_next;

        ossl_quic_cfq_mark_lost(fifd->cfq, cfq_item, UINT32_MAX);

    }

    /* Regenerate flag frames */

    if (pkt->had_handshake_done_frame)

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_HANDSHAKE_DONE,

            UINT64_MAX, pkt,

            fifd->regen_frame_arg);

    if (pkt->had_max_data_frame)

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_MAX_DATA,

            UINT64_MAX, pkt,

            fifd->regen_frame_arg);

    if (pkt->had_max_streams_bidi_frame)

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_MAX_STREAMS_BIDI,

            UINT64_MAX, pkt,

            fifd->regen_frame_arg);

    if (pkt->had_max_streams_uni_frame)

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_MAX_STREAMS_UNI,

            UINT64_MAX, pkt,

            fifd->regen_frame_arg);

    if (pkt->had_ack_frame)

        /*

         * We always use the ACK_WITH_ECN frame type to represent the ACK frame

         * type in our callback; we assume it is the caller's job to decide

         * whether it wants to send ECN data or not.

         */

        fifd->regen_frame(OSSL_QUIC_FRAME_TYPE_ACK_WITH_ECN,

            UINT64_MAX, pkt,

            fifd->regen_frame_arg);

    ossl_quic_txpim_pkt_release(fifd->txpim, pkt);

}

static void on_discarded(void *arg)

{

    QUIC_TXPIM_PKT *pkt = arg;

    QUIC_FIFD *fifd = pkt->fifd;

    QUIC_CFQ_ITEM *cfq_item, *cfq_item_next;

    /*

     * Don't need to do anything to SSTREAMs for STREAM and CRYPTO streams, as

     * we assume caller will clean them up.

     */

    /* GCR */

    for (cfq_item = pkt->retx_head; cfq_item != NULL; cfq_item = cfq_item_next) {

        cfq_item_next = cfq_item->pkt_next;

        ossl_quic_cfq_release(fifd->cfq, cfq_item);

    }

    ossl_quic_txpim_pkt_release(fifd->txpim, pkt);

}

int ossl_quic_fifd_pkt_commit(QUIC_FIFD *fifd, QUIC_TXPIM_PKT *pkt)

{

    QUIC_CFQ_ITEM *cfq_item;

    const QUIC_TXPIM_CHUNK *chunks;

    size_t i, num_chunks;

    QUIC_SSTREAM *sstream;

    pkt->fifd = fifd;

    pkt->ackm_pkt.on_lost = on_lost;

    pkt->ackm_pkt.on_acked = on_acked;

    pkt->ackm_pkt.on_discarded = on_discarded;

    pkt->ackm_pkt.cb_arg = pkt;

    ossl_list_tx_history_init_elem(&pkt->ackm_pkt);

    pkt->ackm_pkt.anext = pkt->ackm_pkt.lnext = NULL;

    /*

     * Mark the CFQ items which have been added to this packet as having been

     * transmitted.

     */

    for (cfq_item = pkt->retx_head;

        cfq_item != NULL;

        cfq_item = cfq_item->pkt_next)

        ossl_quic_cfq_mark_tx(fifd->cfq, cfq_item);

    /*

     * Mark the send stream chunks which have been added to the packet as having

     * been transmitted.

     */

    chunks = ossl_quic_txpim_pkt_get_chunks(pkt);

    num_chunks = ossl_quic_txpim_pkt_get_num_chunks(pkt);

    for (i = 0; i < num_chunks; ++i) {

        sstream = fifd->get_sstream_by_id(chunks[i].stream_id,

            pkt->ackm_pkt.pkt_space,

            fifd->get_sstream_by_id_arg);

        if (sstream == NULL)

            continue;

        if (chunks[i].end >= chunks[i].start

            && !ossl_quic_sstream_mark_transmitted(sstream,

                chunks[i].start,

                chunks[i].end))

            return 0;

        if (chunks[i].has_fin

            && !ossl_quic_sstream_mark_transmitted_fin(sstream,

                chunks[i].end + 1))

            return 0;

    }

    /* Inform the ACKM. */

    return ossl_ackm_on_tx_packet(fifd->ackm, &pkt->ackm_pkt);

}

void ossl_quic_fifd_set_qlog_cb(QUIC_FIFD *fifd, QLOG *(*get_qlog_cb)(void *arg),

    void *get_qlog_cb_arg)

{

    fifd->get_qlog_cb = get_qlog_cb;

    fifd->get_qlog_cb_arg = get_qlog_cb_arg;

}

static void txpim_pkt_remove_cfq_item(QUIC_TXPIM_PKT *pkt, QUIC_CFQ_ITEM *cfq_item)

{

    QUIC_CFQ_ITEM *prev = cfq_item->pkt_prev;

    if (prev != NULL) {

        prev->pkt_next = cfq_item->pkt_next;

    } else {

        pkt->retx_head = cfq_item->pkt_next;

    }

    if (cfq_item->pkt_next != NULL)

        cfq_item->pkt_next->pkt_prev = prev;

    cfq_item->pkt_prev = NULL;

    cfq_item->pkt_next = NULL;

}

void ossl_quic_fifd_pkt_discard_unreliable(QUIC_FIFD *fifd, QUIC_TXPIM_PKT *pkt)

{

    QUIC_CFQ_ITEM *cfq_item, *cfq_next;

    /*

     * The packet has been written to network. We can discard frames we don't

     * retransmit when loss is detected.

     */

    cfq_item = pkt->retx_head;

    while (cfq_item != NULL) {

        /*

         * Discarded items are moved to free list. If item

         * got moved to free list we must also remove it from

         * cfq list kept in pkt, so ACKM does not find it when

         * receives an ACK for pkt.

         */

        if (ossl_quic_cfq_discard_unreliable(fifd->cfq, cfq_item)) {

            cfq_next = cfq_item->pkt_next;

            txpim_pkt_remove_cfq_item(pkt, cfq_item);

            cfq_item = cfq_next;

        } else {

            cfq_item = cfq_item->pkt_next;

        }

    }

}