/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_HTTP) && !defined(USE_HYPER)

#include "urldata.h"

#include <curl/curl.h>

#include "curl_trc.h"

#include "cfilters.h"

#include "connect.h"

#include "multiif.h"

#include "cf-https-connect.h"

#include "http2.h"

#include "vquic/vquic.h"

/* The last 3 #include files should be in this order */

#include "curl_printf.h"

#include "curl_memory.h"

#include "memdebug.h"

typedef enum {

  CF_HC_INIT,

  CF_HC_CONNECT,

  CF_HC_SUCCESS,

  CF_HC_FAILURE

} cf_hc_state;

struct cf_hc_baller {

  const char *name;

  struct Curl_cfilter *cf;

  CURLcode result;

  struct curltime started;

  int reply_ms;

  bool enabled;

};

static void cf_hc_baller_reset(struct cf_hc_baller *b,

                               struct Curl_easy *data)

{

  if(b->cf) {

    Curl_conn_cf_close(b->cf, data);

    Curl_conn_cf_discard_chain(&b->cf, data);

    b->cf = NULL;

  }

  b->result = CURLE_OK;

  b->reply_ms = -1;

}

static bool cf_hc_baller_is_active(struct cf_hc_baller *b)

{

  return b->enabled && b->cf && !b->result;

}

static bool cf_hc_baller_has_started(struct cf_hc_baller *b)

{

  return !!b->cf;

}

static int cf_hc_baller_reply_ms(struct cf_hc_baller *b,

                                 struct Curl_easy *data)

{

  if(b->reply_ms < 0)

    b->cf->cft->query(b->cf, data, CF_QUERY_CONNECT_REPLY_MS,

                      &b->reply_ms, NULL);

  return b->reply_ms;

}

static bool cf_hc_baller_data_pending(struct cf_hc_baller *b,

                                      const struct Curl_easy *data)

{

  return b->cf && !b->result && b->cf->cft->has_data_pending(b->cf, data);

}

struct cf_hc_ctx {

  cf_hc_state state;

  const struct Curl_dns_entry *remotehost;

  struct curltime started;  /* when connect started */

  CURLcode result;          /* overall result */

  struct cf_hc_baller h3_baller;

  struct cf_hc_baller h21_baller;

  int soft_eyeballs_timeout_ms;

  int hard_eyeballs_timeout_ms;

};

static void cf_hc_baller_init(struct cf_hc_baller *b,

                              struct Curl_cfilter *cf,

                              struct Curl_easy *data,

                              const char *name,

                              int transport)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  struct Curl_cfilter *save = cf->next;

  b->name = name;

  cf->next = NULL;

  b->started = Curl_now();

  b->result = Curl_cf_setup_insert_after(cf, data, ctx->remotehost,

                                         transport, CURL_CF_SSL_ENABLE);

  b->cf = cf->next;

  cf->next = save;

}

static CURLcode cf_hc_baller_connect(struct cf_hc_baller *b,

                                     struct Curl_cfilter *cf,

                                     struct Curl_easy *data,

                                     bool *done)

{

  struct Curl_cfilter *save = cf->next;

  cf->next = b->cf;

  b->result = Curl_conn_cf_connect(cf->next, data, FALSE, done);

  b->cf = cf->next; /* it might mutate */

  cf->next = save;

  return b->result;

}

static void cf_hc_reset(struct Curl_cfilter *cf, struct Curl_easy *data)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  if(ctx) {

    cf_hc_baller_reset(&ctx->h3_baller, data);

    cf_hc_baller_reset(&ctx->h21_baller, data);

    ctx->state = CF_HC_INIT;

    ctx->result = CURLE_OK;

    ctx->hard_eyeballs_timeout_ms = data->set.happy_eyeballs_timeout;

    ctx->soft_eyeballs_timeout_ms = data->set.happy_eyeballs_timeout / 2;

  }

}

static CURLcode baller_connected(struct Curl_cfilter *cf,

                                 struct Curl_easy *data,

                                 struct cf_hc_baller *winner)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  DEBUGASSERT(winner->cf);

  if(winner != &ctx->h3_baller)

    cf_hc_baller_reset(&ctx->h3_baller, data);

  if(winner != &ctx->h21_baller)

    cf_hc_baller_reset(&ctx->h21_baller, data);

  CURL_TRC_CF(data, cf, "connect+handshake %s: %dms, 1st data: %dms",

              winner->name, (int)Curl_timediff(Curl_now(), winner->started),

              cf_hc_baller_reply_ms(winner, data));

  cf->next = winner->cf;

  winner->cf = NULL;

  switch(cf->conn->alpn) {

  case CURL_HTTP_VERSION_3:

    infof(data, "using HTTP/3");

    break;

  case CURL_HTTP_VERSION_2:

#ifdef USE_NGHTTP2

    /* Using nghttp2, we add the filter "below" us, so when the conn

     * closes, we tear it down for a fresh reconnect */

    result = Curl_http2_switch_at(cf, data);

    if(result) {

      ctx->state = CF_HC_FAILURE;

      ctx->result = result;

      return result;

    }

#endif

    infof(data, "using HTTP/2");

    break;

  default:

    infof(data, "using HTTP/1.x");

    break;

  }

  ctx->state = CF_HC_SUCCESS;

  cf->connected = TRUE;

  Curl_conn_cf_cntrl(cf->next, data, TRUE,

                     CF_CTRL_CONN_INFO_UPDATE, 0, NULL);

  return result;

}

static bool time_to_start_h21(struct Curl_cfilter *cf,

                              struct Curl_easy *data,

                              struct curltime now)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  timediff_t elapsed_ms;

  if(!ctx->h21_baller.enabled || cf_hc_baller_has_started(&ctx->h21_baller))

    return FALSE;

  if(!ctx->h3_baller.enabled || !cf_hc_baller_is_active(&ctx->h3_baller))

    return TRUE;

  elapsed_ms = Curl_timediff(now, ctx->started);

  if(elapsed_ms >= ctx->hard_eyeballs_timeout_ms) {

    CURL_TRC_CF(data, cf, "hard timeout of %dms reached, starting h21",

                ctx->hard_eyeballs_timeout_ms);

    return TRUE;

  }

  if(elapsed_ms >= ctx->soft_eyeballs_timeout_ms) {

    if(cf_hc_baller_reply_ms(&ctx->h3_baller, data) < 0) {

      CURL_TRC_CF(data, cf, "soft timeout of %dms reached, h3 has not "

                  "seen any data, starting h21",

                  ctx->soft_eyeballs_timeout_ms);

      return TRUE;

    }

    /* set the effective hard timeout again */

    Curl_expire(data, ctx->hard_eyeballs_timeout_ms - elapsed_ms,

                EXPIRE_ALPN_EYEBALLS);

  }

  return FALSE;

}

static CURLcode cf_hc_connect(struct Curl_cfilter *cf,

                              struct Curl_easy *data,

                              bool blocking, bool *done)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  struct curltime now;

  CURLcode result = CURLE_OK;

  (void)blocking;

  if(cf->connected) {

    *done = TRUE;

    return CURLE_OK;

  }

  *done = FALSE;

  now = Curl_now();

  switch(ctx->state) {

  case CF_HC_INIT:

    DEBUGASSERT(!ctx->h3_baller.cf);

    DEBUGASSERT(!ctx->h21_baller.cf);

    DEBUGASSERT(!cf->next);

    CURL_TRC_CF(data, cf, "connect, init");

    ctx->started = now;

    if(ctx->h3_baller.enabled) {

      cf_hc_baller_init(&ctx->h3_baller, cf, data, "h3", TRNSPRT_QUIC);

      if(ctx->h21_baller.enabled)

        Curl_expire(data, ctx->soft_eyeballs_timeout_ms, EXPIRE_ALPN_EYEBALLS);

    }

    else if(ctx->h21_baller.enabled)

      cf_hc_baller_init(&ctx->h21_baller, cf, data, "h21",

                       cf->conn->transport);

    ctx->state = CF_HC_CONNECT;

    FALLTHROUGH();

  case CF_HC_CONNECT:

    if(cf_hc_baller_is_active(&ctx->h3_baller)) {

      result = cf_hc_baller_connect(&ctx->h3_baller, cf, data, done);

      if(!result && *done) {

        result = baller_connected(cf, data, &ctx->h3_baller);

        goto out;

      }

    }

    if(time_to_start_h21(cf, data, now)) {

      cf_hc_baller_init(&ctx->h21_baller, cf, data, "h21",

                        cf->conn->transport);

    }

    if(cf_hc_baller_is_active(&ctx->h21_baller)) {

      CURL_TRC_CF(data, cf, "connect, check h21");

      result = cf_hc_baller_connect(&ctx->h21_baller, cf, data, done);

      if(!result && *done) {

        result = baller_connected(cf, data, &ctx->h21_baller);

        goto out;

      }

    }

    if((!ctx->h3_baller.enabled || ctx->h3_baller.result) &&

       (!ctx->h21_baller.enabled || ctx->h21_baller.result)) {

      /* both failed or disabled. we give up */

      CURL_TRC_CF(data, cf, "connect, all failed");

      result = ctx->result = ctx->h3_baller.enabled?

                              ctx->h3_baller.result : ctx->h21_baller.result;

      ctx->state = CF_HC_FAILURE;

      goto out;

    }

    result = CURLE_OK;

    *done = FALSE;

    break;

  case CF_HC_FAILURE:

    result = ctx->result;

    cf->connected = FALSE;

    *done = FALSE;

    break;

  case CF_HC_SUCCESS:

    result = CURLE_OK;

    cf->connected = TRUE;

    *done = TRUE;

    break;

  }

out:

  CURL_TRC_CF(data, cf, "connect -> %d, done=%d", result, *done);

  return result;

}

static void cf_hc_adjust_pollset(struct Curl_cfilter *cf,

                                  struct Curl_easy *data,

                                  struct easy_pollset *ps)

{

  if(!cf->connected) {

    struct cf_hc_ctx *ctx = cf->ctx;

    struct cf_hc_baller *ballers[2];

    size_t i;

    ballers[0] = &ctx->h3_baller;

    ballers[1] = &ctx->h21_baller;

    for(i = 0; i < sizeof(ballers)/sizeof(ballers[0]); i++) {

      struct cf_hc_baller *b = ballers[i];

      if(!cf_hc_baller_is_active(b))

        continue;

      Curl_conn_cf_adjust_pollset(b->cf, data, ps);

    }

    CURL_TRC_CF(data, cf, "adjust_pollset -> %d socks", ps->num);

  }

}

static bool cf_hc_data_pending(struct Curl_cfilter *cf,

                               const struct Curl_easy *data)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  if(cf->connected)

    return cf->next->cft->has_data_pending(cf->next, data);

  CURL_TRC_CF((struct Curl_easy *)data, cf, "data_pending");

  return cf_hc_baller_data_pending(&ctx->h3_baller, data)

         || cf_hc_baller_data_pending(&ctx->h21_baller, data);

}

static struct curltime cf_get_max_baller_time(struct Curl_cfilter *cf,

                                              struct Curl_easy *data,

                                              int query)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  struct Curl_cfilter *cfb;

  struct curltime t, tmax;

  memset(&tmax, 0, sizeof(tmax));

  memset(&t, 0, sizeof(t));

  cfb = ctx->h21_baller.enabled? ctx->h21_baller.cf : NULL;

  if(cfb && !cfb->cft->query(cfb, data, query, NULL, &t)) {

    if((t.tv_sec || t.tv_usec) && Curl_timediff_us(t, tmax) > 0)

      tmax = t;

  }

  memset(&t, 0, sizeof(t));

  cfb = ctx->h3_baller.enabled? ctx->h3_baller.cf : NULL;

  if(cfb && !cfb->cft->query(cfb, data, query, NULL, &t)) {

    if((t.tv_sec || t.tv_usec) && Curl_timediff_us(t, tmax) > 0)

      tmax = t;

  }

  return tmax;

}

static CURLcode cf_hc_query(struct Curl_cfilter *cf,

                            struct Curl_easy *data,

                            int query, int *pres1, void *pres2)

{

  if(!cf->connected) {

    switch(query) {

    case CF_QUERY_TIMER_CONNECT: {

      struct curltime *when = pres2;

      *when = cf_get_max_baller_time(cf, data, CF_QUERY_TIMER_CONNECT);

      return CURLE_OK;

    }

    case CF_QUERY_TIMER_APPCONNECT: {

      struct curltime *when = pres2;

      *when = cf_get_max_baller_time(cf, data, CF_QUERY_TIMER_APPCONNECT);

      return CURLE_OK;

    }

    default:

      break;

    }

  }

  return cf->next?

    cf->next->cft->query(cf->next, data, query, pres1, pres2) :

    CURLE_UNKNOWN_OPTION;

}

static void cf_hc_close(struct Curl_cfilter *cf, struct Curl_easy *data)

{

  CURL_TRC_CF(data, cf, "close");

  cf_hc_reset(cf, data);

  cf->connected = FALSE;

  if(cf->next) {

    cf->next->cft->do_close(cf->next, data);

    Curl_conn_cf_discard_chain(&cf->next, data);

  }

}

static void cf_hc_destroy(struct Curl_cfilter *cf, struct Curl_easy *data)

{

  struct cf_hc_ctx *ctx = cf->ctx;

  (void)data;

  CURL_TRC_CF(data, cf, "destroy");

  cf_hc_reset(cf, data);

  Curl_safefree(ctx);

}

struct Curl_cftype Curl_cft_http_connect = {

  "HTTPS-CONNECT",

  0,

  CURL_LOG_LVL_NONE,

  cf_hc_destroy,

  cf_hc_connect,

  cf_hc_close,

  Curl_cf_def_get_host,

  cf_hc_adjust_pollset,

  cf_hc_data_pending,

  Curl_cf_def_send,

  Curl_cf_def_recv,

  Curl_cf_def_cntrl,

  Curl_cf_def_conn_is_alive,

  Curl_cf_def_conn_keep_alive,

  cf_hc_query,

};

static CURLcode cf_hc_create(struct Curl_cfilter **pcf,

                             struct Curl_easy *data,

                             const struct Curl_dns_entry *remotehost,

                             bool try_h3, bool try_h21)

{

  struct Curl_cfilter *cf = NULL;

  struct cf_hc_ctx *ctx;

  CURLcode result = CURLE_OK;

  (void)data;

  ctx = calloc(1, sizeof(*ctx));

  if(!ctx) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  ctx->remotehost = remotehost;

  ctx->h3_baller.enabled = try_h3;

  ctx->h21_baller.enabled = try_h21;

  result = Curl_cf_create(&cf, &Curl_cft_http_connect, ctx);

  if(result)

    goto out;

  ctx = NULL;

  cf_hc_reset(cf, data);

out:

  *pcf = result? NULL : cf;

  free(ctx);

  return result;

}

static CURLcode cf_http_connect_add(struct Curl_easy *data,

                                    struct connectdata *conn,

                                    int sockindex,

                                    const struct Curl_dns_entry *remotehost,

                                    bool try_h3, bool try_h21)

{

  struct Curl_cfilter *cf;

  CURLcode result = CURLE_OK;

  DEBUGASSERT(data);

  result = cf_hc_create(&cf, data, remotehost, try_h3, try_h21);

  if(result)

    goto out;

  Curl_conn_cf_add(data, conn, sockindex, cf);

out:

  return result;

}

CURLcode Curl_cf_https_setup(struct Curl_easy *data,

                             struct connectdata *conn,

                             int sockindex,

                             const struct Curl_dns_entry *remotehost)

{

  bool try_h3 = FALSE, try_h21 = TRUE; /* defaults, for now */

  CURLcode result = CURLE_OK;

  (void)sockindex;

  (void)remotehost;

  if(!conn->bits.tls_enable_alpn)

    goto out;

  if(data->state.httpwant == CURL_HTTP_VERSION_3ONLY) {

    result = Curl_conn_may_http3(data, conn);

    if(result) /* can't do it */

      goto out;

    try_h3 = TRUE;

    try_h21 = FALSE;

  }

  else if(data->state.httpwant >= CURL_HTTP_VERSION_3) {

    /* We assume that silently not even trying H3 is ok here */

    /* TODO: should we fail instead? */

    try_h3 = (Curl_conn_may_http3(data, conn) == CURLE_OK);

    try_h21 = TRUE;

  }

  result = cf_http_connect_add(data, conn, sockindex, remotehost,

                               try_h3, try_h21);

out:

  return result;

}

#endif /* !defined(CURL_DISABLE_HTTP) && !defined(USE_HYPER) */