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

 *                                  _   _ ____  _

 *  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"

#include "urldata.h"

#include "cfilters.h"

#include "cf-haproxy.h"

#include "cf-ip-happy.h"

#include "cf-setup.h"

#include "curl_trc.h"

#include "connect.h"

#include "http_proxy.h"

#include "socks.h"

#include "vquic/cf-capsule.h"

#include "vquic/vquic.h"

#include "vtls/vtls.h"

typedef enum {

  CF_SETUP_INIT,

  CF_SETUP_CNNCT_EYEBALLS,

  CF_SETUP_CNNCT_SOCKS,

  CF_SETUP_CNNCT_HTTP_PROXY,

  CF_SETUP_CNNCT_HAPROXY,

  CF_SETUP_CNNCT_SSL,

  CF_SETUP_DONE

} cf_setup_state;

struct cf_setup_ctx {

  cf_setup_state state;

  int ssl_mode;

  uint8_t transport;

  uint8_t retry_count;

};

#ifndef CURL_DISABLE_PROXY

static CURLcode cf_setup_add_haproxy(struct Curl_cfilter *cf,

                                     struct Curl_easy *data)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  if(ctx->state < CF_SETUP_CNNCT_HAPROXY) {

    if(data->set.haproxyprotocol) {

      if(ctx->transport == TRNSPRT_QUIC) {

        failf(data, "haproxy protocol does not support QUIC");

        return CURLE_UNSUPPORTED_PROTOCOL;

      }

      result = Curl_cf_haproxy_insert_after(cf, data);

      if(result) {

        CURL_TRC_CF(data, cf, "adding HAPROXY filter failed -> %d",

                    (int)result);

        return result;

      }

      CURL_TRC_CF(data, cf, "added HAPROXY filter");

    }

    ctx->state = CF_SETUP_CNNCT_HAPROXY;

  }

  return result;

}

static CURLcode cf_setup_add_socks(struct Curl_cfilter *cf,

                                   struct Curl_easy *data)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  if(ctx->state < CF_SETUP_CNNCT_SOCKS && cf->conn->socks_proxy.peer) {

    /* Add a SOCKS proxy to go through `first_peer` to `second_peer`*/

    struct Curl_peer *second_peer;

    if(cf->conn->http_proxy.peer)

      second_peer = cf->conn->http_proxy.peer;

    else

      second_peer = Curl_conn_get_destination(cf->conn, cf->sockindex);

    if(!second_peer)

      return CURLE_FAILED_INIT;

    result = Curl_cf_socks_proxy_insert_after(

      cf, data, second_peer, cf->conn->ip_version,

      cf->conn->socks_proxy.proxytype,

      cf->conn->socks_proxy.creds);

    if(result) {

      CURL_TRC_CF(data, cf, "adding SOCKS filter failed -> %d", (int)result);

      return result;

    }

    CURL_TRC_CF(data, cf, "added SOCKS filter to %s:%u",

                second_peer->hostname, second_peer->port);

    ctx->state = CF_SETUP_CNNCT_SOCKS;

  }

  return result;

}

#ifndef CURL_DISABLE_HTTP

static CURLcode cf_setup_add_http_proxy(struct Curl_cfilter *cf,

                                        struct Curl_easy *data)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  if(ctx->state < CF_SETUP_CNNCT_HTTP_PROXY &&

     cf->conn->http_proxy.peer && !cf->conn->bits.origin_is_proxy) {

    struct Curl_peer *peer = cf->conn->http_proxy.peer;

    struct Curl_peer *tunnel_peer =

      Curl_conn_get_destination(cf->conn, cf->sockindex);

#ifdef USE_SSL

    if(CURL_PROXY_IS_HTTPS(cf->conn->http_proxy.proxytype) &&

       !Curl_conn_is_ssl(cf->conn, cf->sockindex)) {

      result = Curl_cf_ssl_proxy_insert_after(

        cf, data, cf->conn->http_proxy.peer);

      if(result) {

        CURL_TRC_CF(data, cf, "adding SSL filter for HTTP proxy failed -> %d",

                    (int)result);

        return result;

      }

      CURL_TRC_CF(data, cf, "added SSL filter for HTTP proxy");

    }

#endif /* USE_SSL */

    result = Curl_cf_http_proxy_insert_after(

      cf, data, peer, tunnel_peer,

      ctx->transport, cf->conn->http_proxy.proxytype);

    if(result) {

      CURL_TRC_CF(data, cf, "adding HTTP proxy tunnel filter failed -> %d",

                  (int)result);

      return result;

    }

    CURL_TRC_CF(data, cf, "added HTTP proxy tunnel filter");

    ctx->state = CF_SETUP_CNNCT_HTTP_PROXY;

  }

  return result;

}

#endif /* !CURL_DISABLE_HTTP */

#endif /* CURL_DISABLE_PROXY */

/* Get the origin curl connects its socket to.

 * Can be origin or the first proxy. */

static struct Curl_peer *conn_get_first_origin(struct connectdata *conn,

                                             int sockindex)

{

#ifndef CURL_DISABLE_PROXY

  if(conn->socks_proxy.peer)

    return conn->socks_proxy.peer;

  if(conn->http_proxy.peer)

    return conn->http_proxy.peer;

#endif

  return (sockindex == SECONDARYSOCKET) ? conn->origin2 : conn->origin;

}

static CURLcode cf_setup_add_ip_happy(struct Curl_cfilter *cf,

                                      struct Curl_easy *data)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  if(ctx->state < CF_SETUP_CNNCT_EYEBALLS) {

    /* What is the first hop we directly connect to and what transport

     * do we use for it? Only on the first hop we can do Happy Eyeballs.

     * first_origin and first_peer differ on --connect-to. */

    struct Curl_peer *first_origin =

      conn_get_first_origin(cf->conn, cf->sockindex);

    struct Curl_peer *first_peer =

      Curl_conn_get_first_peer(cf->conn, cf->sockindex);

    struct Curl_peer *tunnel_peer = NULL;

    uint8_t first_transport = ctx->transport;

    if(!first_peer)

      return CURLE_FAILED_INIT;

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

    if(cf->conn->http_proxy.peer && !cf->conn->bits.origin_is_proxy) {

      first_transport =

        Curl_http_proxy_transport(cf->conn->http_proxy.proxytype);

      tunnel_peer = Curl_conn_get_destination(cf->conn, cf->sockindex);

      if((first_transport == TRNSPRT_QUIC) && cf->conn->socks_proxy.peer) {

        failf(data, "HTTP/3 proxy not possible via SOCKS");

        return CURLE_UNSUPPORTED_PROTOCOL;

      }

    }

#endif /* !CURL_DISABLE_PROXY && !CURL_DISABLE_HTTP */

    result = Curl_cf_ip_happy_insert_after(cf, data, first_origin, first_peer,

                                           first_transport,

                                           tunnel_peer, ctx->transport);

    if(result) {

      CURL_TRC_CF(data, cf, "adding happy eyeballs failed -> %d", (int)result);

      return result;

    }

    if(tunnel_peer && (first_transport == TRNSPRT_QUIC)) {

      CURL_TRC_CF(data, cf, "happy eyeballing to HTTP/3 proxy %s:%u",

                  first_peer->hostname, first_peer->port);

      ctx->state = CF_SETUP_CNNCT_HTTP_PROXY;

    }

    else {

      CURL_TRC_CF(data, cf, "happy eyeballing to %s %s:%u",

                  tunnel_peer ? "proxy" : "origin",

                  first_peer->hostname, first_peer->port);

      ctx->state = CF_SETUP_CNNCT_EYEBALLS;

    }

  }

  return result;

}

static CURLcode cf_setup_add_origin_filters(struct Curl_cfilter *cf,

                                            struct Curl_easy *data)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  (void)data; /* not used in all builds */

  if(ctx->state < CF_SETUP_CNNCT_SSL) {

#if !defined(CURL_DISABLE_HTTP) && defined(USE_HTTP3) && \

    !defined(CURL_DISABLE_PROXY)

    /* Wanting QUIC with an HTTP tunneling filter, we now need to add

     * the QUIC filter on top. Without tunneling, this has already

     * happened in the Happy Eyeball filter. */

    if(ctx->transport == TRNSPRT_QUIC &&

       cf->conn->http_proxy.peer && !cf->conn->bits.origin_is_proxy) {

      struct Curl_peer *origin = Curl_conn_get_origin(cf->conn, cf->sockindex);

      struct Curl_peer *peer =

        Curl_conn_get_destination(cf->conn, cf->sockindex);

      result = Curl_cf_capsule_insert_after(cf, data);

      if(result) {

        CURL_TRC_CF(data, cf, "adding capsule filter failed -> %d",

                    (int)result);

        return result;

      }

      result = Curl_cf_quic_insert_after(cf, origin, peer);

      if(result) {

        CURL_TRC_CF(data, cf, "adding QUIC filter failed -> %d", (int)result);

        return result;

      }

      CURL_TRC_CF(data, cf, "added QUIC filter for origin");

    }

    else

#endif /* !CURL_DISABLE_HTTP && USE_HTTP3 && CURL_DISABLE_PROXY */

#ifdef USE_SSL

    if((ctx->ssl_mode == CURL_CF_SSL_ENABLE ||

        (ctx->ssl_mode != CURL_CF_SSL_DISABLE &&

         cf->conn->scheme->flags & PROTOPT_SSL)) && /* we want SSL */

       !Curl_conn_is_ssl(cf->conn, cf->sockindex)) { /* it is missing */

#ifndef CURL_DISABLE_PROXY

      if(cf->conn->bits.origin_is_proxy) {

        result = Curl_cf_ssl_proxy_insert_after(cf, data, cf->conn->origin);

      }

      else

#endif

      {

        /* FTP is a bitch. Wherever we really connect to on the DATA

         * (secondary) connection, many servers require TLS sessions reuse

         * to prove they are talking to the same client.

         * For the TLS session lookup to work, we need to instantiate

         * the SSL filter with the same peers as FIRSTSOCKET. See #22225

         * Meaning: cf->sockindex does not matter here. */

        result = Curl_cf_ssl_insert_after(cf, data,

          Curl_conn_get_origin(cf->conn, FIRSTSOCKET),

          Curl_conn_get_destination(cf->conn, FIRSTSOCKET));

      }

      if(result) {

        CURL_TRC_CF(data, cf, "adding SSL filter for origin failed -> %d",

                    (int)result);

        return result;

      }

      CURL_TRC_CF(data, cf, "added SSL filter for origin");

    }

#endif /* USE_SSL */

    ctx->state = CF_SETUP_CNNCT_SSL;

  }

  return result;

}

static CURLcode cf_setup_connect_steps(struct Curl_cfilter *cf,

                                       struct Curl_easy *data,

                                       bool *done)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result = CURLE_OK;

  if(cf->connected) {

    *done = TRUE;

    return CURLE_OK;

  }

  /* connect current sub-chain */

connect_sub_chain:

  VERBOSE(Curl_conn_trc_filters(data, cf->sockindex, "cf_setup_connect"));

  if(cf->next && !cf->next->connected) {

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

    if(result || !*done)

      return result;

  }

  result = cf_setup_add_ip_happy(cf, data);

  if(result)

    return result;

  if(!cf->next || !cf->next->connected)

    goto connect_sub_chain;

#ifndef CURL_DISABLE_PROXY

  result = cf_setup_add_socks(cf, data);

  if(result)

    return result;

  if(!cf->next || !cf->next->connected)

    goto connect_sub_chain;

#ifndef CURL_DISABLE_HTTP

  result = cf_setup_add_http_proxy(cf, data);

  if(result)

    return result;

  if(!cf->next || !cf->next->connected)

    goto connect_sub_chain;

#endif /* !CURL_DISABLE_HTTP */

  result = cf_setup_add_haproxy(cf, data);

  if(result)

    return result;

  if(!cf->next || !cf->next->connected)

    goto connect_sub_chain;

#endif /* !CURL_DISABLE_PROXY */

  result = cf_setup_add_origin_filters(cf, data);

  if(result)

    return result;

  if(!cf->next || !cf->next->connected)

    goto connect_sub_chain;

  ctx->state = CF_SETUP_DONE;

  cf->connected = TRUE;

  *done = TRUE;

  return CURLE_OK;

}

static CURLcode cf_setup_connect(struct Curl_cfilter *cf,

                                 struct Curl_easy *data,

                                 bool *done)

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURLcode result;

  /* In some situations, a server/proxy may close the connection and

   * we need to connect again (HTTP/1.x proxy auth, for example).

   * We used to close the filters and reuse them for another attempt,

   * however that complicates filter code and it is simpler to tear them

   * all down and start over. */

retry:

  result = cf_setup_connect_steps(cf, data, done);

  if(result == CURLE_AGAIN) {

    ++ctx->retry_count;

    if(ctx->retry_count > 5) /* arbitrary limit, better just timeout? */

      return CURLE_COULDNT_CONNECT;

    CURL_TRC_CF(data, cf, "retrying connect, %d. time", ctx->retry_count);

    Curl_conn_cf_discard_chain(&cf->next, data);

    ctx->state = CF_SETUP_INIT;

    goto retry;

  }

  return result;

}

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

{

  struct cf_setup_ctx *ctx = cf->ctx;

  CURL_TRC_CF(data, cf, "destroy");

  curlx_safefree(ctx);

}

struct Curl_cftype Curl_cft_setup = {

  "SETUP",

  CF_TYPE_SETUP,

  CURL_LOG_LVL_NONE,

  cf_setup_destroy,

  cf_setup_connect,

  Curl_cf_def_shutdown,

  Curl_cf_def_adjust_pollset,

  Curl_cf_def_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,

  Curl_cf_def_query,

};

static CURLcode cf_setup_create(struct Curl_cfilter **pcf,

                                struct Curl_easy *data,

                                uint8_t transport,

                                int ssl_mode)

{

  struct Curl_cfilter *cf = NULL;

  struct cf_setup_ctx *ctx;

  CURLcode result = CURLE_OK;

  (void)data;

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

  if(!ctx) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  ctx->state = CF_SETUP_INIT;

  ctx->ssl_mode = ssl_mode;

  ctx->transport = transport;

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

  if(result)

    goto out;

  ctx = NULL;

out:

  *pcf = result ? NULL : cf;

  if(ctx) {

    curlx_free(ctx);

  }

  return result;

}

CURLcode Curl_cf_setup_add(struct Curl_easy *data,

                           struct connectdata *conn,

                           int sockindex,

                           uint8_t transport,

                           int ssl_mode)

{

  struct Curl_cfilter *cf;

  CURLcode result = CURLE_OK;

  DEBUGASSERT(data);

  result = cf_setup_create(&cf, data, transport, ssl_mode);

  if(result)

    goto out;

  Curl_conn_cf_add(data, conn, sockindex, cf);

out:

  return result;

}

CURLcode Curl_cf_setup_insert_after(struct Curl_cfilter *cf_at,

                                    struct Curl_easy *data,

                                    uint8_t transport,

                                    int ssl_mode)

{

  struct Curl_cfilter *cf;

  CURLcode result;

  DEBUGASSERT(data);

  result = cf_setup_create(&cf, data, transport, ssl_mode);

  if(result)

    goto out;

  Curl_conn_cf_insert_after(cf_at, cf);

out:

  return result;

}