/*

 * Copyright 2023-2025 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_engine.h"

#include "internal/quic_port.h"

#include "quic_engine_local.h"

#include "quic_port_local.h"

#include "../ssl_local.h"

/*

 * QUIC Engine

 * ===========

 */

static int qeng_init(QUIC_ENGINE *qeng, uint64_t reactor_flags);

static void qeng_cleanup(QUIC_ENGINE *qeng);

static void qeng_tick(QUIC_TICK_RESULT *res, void *arg, uint32_t flags);

DEFINE_LIST_OF_IMPL(port, QUIC_PORT);

QUIC_ENGINE *ossl_quic_engine_new(const QUIC_ENGINE_ARGS *args)

{

    QUIC_ENGINE *qeng;

    if ((qeng = OPENSSL_zalloc(sizeof(QUIC_ENGINE))) == NULL)

        return NULL;

    qeng->libctx            = args->libctx;

    qeng->propq             = args->propq;

    qeng->mutex             = args->mutex;

    if (!qeng_init(qeng, args->reactor_flags)) {

        OPENSSL_free(qeng);

        return NULL;

    }

    return qeng;

}

void ossl_quic_engine_free(QUIC_ENGINE *qeng)

{

    if (qeng == NULL)

        return;

    qeng_cleanup(qeng);

    OPENSSL_free(qeng);

}

static int qeng_init(QUIC_ENGINE *qeng, uint64_t reactor_flags)

{

    return ossl_quic_reactor_init(&qeng->rtor, qeng_tick, qeng,

                                  qeng->mutex,

                                  ossl_time_zero(), reactor_flags);

}

static void qeng_cleanup(QUIC_ENGINE *qeng)

{

    assert(ossl_list_port_num(&qeng->port_list) == 0);

    ossl_quic_reactor_cleanup(&qeng->rtor);

}

QUIC_REACTOR *ossl_quic_engine_get0_reactor(QUIC_ENGINE *qeng)

{

    return &qeng->rtor;

}

CRYPTO_MUTEX *ossl_quic_engine_get0_mutex(QUIC_ENGINE *qeng)

{

    return qeng->mutex;

}

OSSL_TIME ossl_quic_engine_get_time(QUIC_ENGINE *qeng)

{

    if (qeng->now_cb == NULL)

        return ossl_time_now();

    return qeng->now_cb(qeng->now_cb_arg);

}

OSSL_TIME ossl_quic_engine_make_real_time(QUIC_ENGINE *qeng, OSSL_TIME tm)

{

    OSSL_TIME offset;

    if (qeng->now_cb != NULL

            && !ossl_time_is_zero(tm)

            && !ossl_time_is_infinite(tm)) {

        offset = qeng->now_cb(qeng->now_cb_arg);

        /* If tm is earlier than offset then tm will end up as "now" */

        tm = ossl_time_add(ossl_time_subtract(tm, offset), ossl_time_now());

    }

    return tm;

}

void ossl_quic_engine_set_time_cb(QUIC_ENGINE *qeng,

                                  OSSL_TIME (*now_cb)(void *arg),

                                  void *now_cb_arg)

{

    qeng->now_cb = now_cb;

    qeng->now_cb_arg = now_cb_arg;

}

void ossl_quic_engine_set_inhibit_tick(QUIC_ENGINE *qeng, int inhibit)

{

    qeng->inhibit_tick = (inhibit != 0);

}

OSSL_LIB_CTX *ossl_quic_engine_get0_libctx(QUIC_ENGINE *qeng)

{

    return qeng->libctx;

}

const char *ossl_quic_engine_get0_propq(QUIC_ENGINE *qeng)

{

    return qeng->propq;

}

void ossl_quic_engine_update_poll_descriptors(QUIC_ENGINE *qeng, int force)

{

    QUIC_PORT *port;

    /*

     * TODO(QUIC MULTIPORT): The implementation of

     * ossl_quic_port_update_poll_descriptors assumes an engine only ever has a

     * single port for now due to reactor limitations. This limitation will be

     * removed in future.

     *

     * TODO(QUIC MULTIPORT): Consider only iterating the port list when dirty at

     * the engine level in future when we can have multiple ports. This is not

     * important currently as the port list has a single entry.

     */

    OSSL_LIST_FOREACH(port, port, &qeng->port_list)

        ossl_quic_port_update_poll_descriptors(port, force);

}

/*

 * QUIC Engine: Child Object Lifecycle Management

 * ==============================================

 */

QUIC_PORT *ossl_quic_engine_create_port(QUIC_ENGINE *qeng,

                                        const QUIC_PORT_ARGS *args)

{

    QUIC_PORT_ARGS largs = *args;

    if (ossl_list_port_num(&qeng->port_list) > 0)

        /* TODO(QUIC MULTIPORT): We currently support only one port. */

        return NULL;

    if (largs.engine != NULL)

        return NULL;

    largs.engine = qeng;

    return ossl_quic_port_new(&largs);

}

/*

 * QUIC Engine: Ticker-Mutator

 * ===========================

 */

/*

 * The central ticker function called by the reactor. This does everything, or

 * at least everything network I/O related. Best effort - not allowed to fail

 * "loudly".

 */

static void qeng_tick(QUIC_TICK_RESULT *res, void *arg, uint32_t flags)

{

    QUIC_ENGINE *qeng = arg;

    QUIC_PORT *port;

    res->net_read_desired     = 0;

    res->net_write_desired    = 0;

    res->notify_other_threads = 0;

    res->tick_deadline        = ossl_time_infinite();

    if (qeng->inhibit_tick)

        return;

    /* Iterate through all ports and service them. */

    OSSL_LIST_FOREACH(port, port, &qeng->port_list) {

        QUIC_TICK_RESULT subr = {0};

        ossl_quic_port_subtick(port, &subr, flags);

        ossl_quic_tick_result_merge_into(res, &subr);

    }

}