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

 *                                  _   _ ____  _

 *  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"

#ifndef CURL_DISABLE_PROXY

#include "urldata.h"

#include "cfilters.h"

#include "cf-haproxy.h"

#include "connect.h"

#include "curl_addrinfo.h"

#include "curl_trc.h"

#include "select.h"

typedef enum {

  HAPROXY_INIT,     /* init/default/no tunnel state */

  HAPROXY_SEND,     /* data_out being sent */

  HAPROXY_DONE      /* all work done */

} haproxy_state;

struct cf_haproxy_ctx {

  int state;

  struct dynbuf data_out;

};

static void cf_haproxy_ctx_reset(struct cf_haproxy_ctx *ctx)

{

  DEBUGASSERT(ctx);

  ctx->state = HAPROXY_INIT;

  curlx_dyn_reset(&ctx->data_out);

}

static void cf_haproxy_ctx_free(struct cf_haproxy_ctx *ctx)

{

  if(ctx) {

    curlx_dyn_free(&ctx->data_out);

    curlx_free(ctx);

  }

}

static CURLcode cf_haproxy_date_out_set(struct Curl_cfilter *cf,

                                        struct Curl_easy *data)

{

  /* We fake a client connection report to the upstream server

   * with the HAProxy protocol, reporting the client's source

   * and destination IP addresses and ports.

   * addresses: either the ones used to talk to the upstream

   *            OR the value supplied by the user

   * ports: the ports used in the upstream connection */

  const char *client_source_ip;

  const char *client_dest_ip;

  struct cf_haproxy_ctx *ctx = cf->ctx;

  CURLcode result;

  struct ip_quadruple ipquad;

  bool is_ipv6;

  DEBUGASSERT(ctx);

  DEBUGASSERT(ctx->state == HAPROXY_INIT);

#ifdef USE_UNIX_SOCKETS

  if(Curl_conn_get_first_peer(cf->conn, cf->sockindex)->unix_socket)

    /* the buffer is large enough to hold this! */

    result = curlx_dyn_addn(&ctx->data_out, STRCONST("PROXY UNKNOWN\r\n"));

  else {

#endif /* USE_UNIX_SOCKETS */

  result = Curl_conn_cf_get_ip_info(cf->next, data, &is_ipv6, &ipquad);

  if(result)

    return result;

  if(data->set.str[STRING_HAPROXY_CLIENT_IP]) {

    client_source_ip = data->set.str[STRING_HAPROXY_CLIENT_IP];

    client_dest_ip = client_source_ip;

    is_ipv6 = !Curl_is_ipv4addr(client_source_ip);

  }

  else {

    client_source_ip = ipquad.local_ip;

    client_dest_ip = ipquad.remote_ip;

  }

  result = curlx_dyn_addf(&ctx->data_out, "PROXY %s %s %s %i %i\r\n",

                          is_ipv6 ? "TCP6" : "TCP4",

                          client_source_ip, client_dest_ip,

                          ipquad.local_port, ipquad.remote_port);

#ifdef USE_UNIX_SOCKETS

  }

#endif /* USE_UNIX_SOCKETS */

  return result;

}

static CURLcode cf_haproxy_connect(struct Curl_cfilter *cf,

                                   struct Curl_easy *data,

                                   bool *done)

{

  struct cf_haproxy_ctx *ctx = cf->ctx;

  CURLcode result;

  size_t len;

  DEBUGASSERT(ctx);

  if(cf->connected) {

    *done = TRUE;

    return CURLE_OK;

  }

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

  if(result || !*done)

    return result;

  switch(ctx->state) {

  case HAPROXY_INIT:

    result = cf_haproxy_date_out_set(cf, data);

    if(result)

      goto out;

    ctx->state = HAPROXY_SEND;

    FALLTHROUGH();

  case HAPROXY_SEND:

    len = curlx_dyn_len(&ctx->data_out);

    if(len > 0) {

      size_t nwritten;

      result = Curl_conn_cf_send(cf->next, data,

                                 curlx_dyn_uptr(&ctx->data_out), len, FALSE,

                                 &nwritten);

      if(result) {

        if(result != CURLE_AGAIN)

          goto out;

        result = CURLE_OK;

        nwritten = 0;

      }

      curlx_dyn_tail(&ctx->data_out, len - nwritten);

      if(curlx_dyn_len(&ctx->data_out) > 0) {

        result = CURLE_OK;

        goto out;

      }

    }

    ctx->state = HAPROXY_DONE;

    FALLTHROUGH();

  default:

    curlx_dyn_free(&ctx->data_out);

    break;

  }

out:

  *done = (!result) && (ctx->state == HAPROXY_DONE);

  cf->connected = *done;

  return result;

}

static void cf_haproxy_destroy(struct Curl_cfilter *cf,

                               struct Curl_easy *data)

{

  CURL_TRC_CF(data, cf, "destroy");

  cf_haproxy_ctx_free(cf->ctx);

}

static void cf_haproxy_close(struct Curl_cfilter *cf,

                             struct Curl_easy *data)

{

  CURL_TRC_CF(data, cf, "close");

  cf->connected = FALSE;

  cf_haproxy_ctx_reset(cf->ctx);

  if(cf->next)

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

}

static CURLcode cf_haproxy_adjust_pollset(struct Curl_cfilter *cf,

                                          struct Curl_easy *data,

                                          struct easy_pollset *ps)

{

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

    /* If we are not connected, but the filter "below" is

     * and not waiting on something, we are sending. */

    return Curl_pollset_set_out_only(

      data, ps, Curl_conn_cf_get_socket(cf, data));

  }

  return CURLE_OK;

}

struct Curl_cftype Curl_cft_haproxy = {

  "HAPROXY",

  CF_TYPE_PROXY | CF_TYPE_SETUP,

  0,

  cf_haproxy_destroy,

  cf_haproxy_connect,

  cf_haproxy_close,

  Curl_cf_def_shutdown,

  cf_haproxy_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_haproxy_create(struct Curl_cfilter **pcf,

                                  struct Curl_easy *data)

{

  struct Curl_cfilter *cf = NULL;

  struct cf_haproxy_ctx *ctx;

  CURLcode result;

  (void)data;

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

  if(!ctx) {

    result = CURLE_OUT_OF_MEMORY;

    goto out;

  }

  ctx->state = HAPROXY_INIT;

  curlx_dyn_init(&ctx->data_out, DYN_HAXPROXY);

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

  if(result)

    goto out;

  ctx = NULL;

out:

  cf_haproxy_ctx_free(ctx);

  *pcf = result ? NULL : cf;

  return result;

}

CURLcode Curl_cf_haproxy_insert_after(struct Curl_cfilter *cf_at,

                                      struct Curl_easy *data)

{

  struct Curl_cfilter *cf;

  CURLcode result;

  result = cf_haproxy_create(&cf, data);

  if(result)

    goto out;

  Curl_conn_cf_insert_after(cf_at, cf);

out:

  return result;

}

#endif /* !CURL_DISABLE_PROXY */