text: /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
  
  /*  Fluent Bit
   *  ==========
   *  Copyright (C) 2019-2021 The Fluent Bit Authors
   *  Copyright (C) 2015-2018 Treasure Data Inc.
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  
  #include <fluent-bit/flb_info.h>
  #include <fluent-bit/flb_output.h>
  #include <fluent-bit/flb_utils.h>
  #include <fluent-bit/flb_network.h>
  #include <fluent-bit/flb_time.h>
  #include <fluent-bit/flb_upstream.h>
  #include <fluent-bit/flb_sha512.h>
  #include <fluent-bit/flb_pack.h>
  #include <fluent-bit/flb_sds.h>
  #include <fluent-bit/flb_http_client.h>
  #include <fluent-bit/flb_config_map.h>
  #include <msgpack.h>
  
  #include "websocket.h"
  #include "websocket_conf.h"
  struct flb_output_plugin out_websocket_plugin;
  
  #define SECURED_BY "Fluent Bit"
  
  
  static int flb_ws_handshake(struct flb_upstream_conn *u_conn,
                                      struct flb_out_ws *ctx)
  {
      int ret;
      size_t bytes_sent;
      struct flb_http_client *c;
  
      if (!u_conn) {
          flb_error("[output_ws] upstream connection error");
          return -1;
      }
  
      /* Compose HTTP Client request */
      c = flb_http_client(u_conn, FLB_HTTP_GET, ctx->uri,
                          NULL, 0, NULL, 0, NULL, 0);
      if (!c) {
         flb_upstream_conn_release(u_conn);
         return -1;
      }
  
      flb_http_buffer_size(c, ctx->buffer_size);
      flb_http_add_header(c, "Upgrade", 7, "websocket", 9);
      flb_http_add_header(c, "Connection", 10, "Upgrade", 7);
      flb_http_add_header(c, "Sec-WebSocket-Key", 17, "dGhlIHNhbXBsZSBub25jZQ==", 24);
      flb_http_add_header(c, "Sec-WebSocket-Version", 21, "13", 2);
  
      /* Perform request*/
      ret = flb_http_do(c, &bytes_sent);
  
      if (ret != 0 || c->resp.status != 101) {
          if (c->resp.payload_size > 0) {
              flb_debug("[output_ws] Websocket Server Response\n%s",
                  c->resp.payload);
          }
          flb_http_client_destroy(c);
          flb_upstream_conn_release(u_conn);
          flb_debug("[out_ws] Http Get Operation ret = %i, http resp = %i", ret, c->resp.status);
          return -1;
      }
      flb_http_client_destroy(c);
      return 0;
  }
  
  static void flb_ws_mask(char *data, int len, char *mask)
  {
      int i;
      for (i=0;i<len;++i) {
          *(data+i) ^= *(mask+(i%4));
      }
  }
  
  static int flb_ws_sendDataFrameHeader(struct flb_upstream_conn *u_conn,
                                        struct flb_out_ws *ctx, const void *data, size_t bytes)
  {
      int ret = -1;
      char* data_frame_head;
      size_t bytes_sent;
      int data_frame_head_len = 0;
      //TODO use random function to generate masking_key
      char masking_key[4] = {0x12, 0x34, 0x56, 0x78};
      unsigned long long payloadSize = bytes;
  
      flb_ws_mask((char *)data, payloadSize, masking_key);
      if (payloadSize < 126) {
          data_frame_head = (char *)flb_malloc(6);
          if (!data_frame_head) {
              flb_errno();
              return -1;
          }
          data_frame_head[0] = 0x81;
          data_frame_head[1] = (payloadSize & 0xff) | 0x80;
          data_frame_head[2] = masking_key[0];
          data_frame_head[3] = masking_key[1];
          data_frame_head[4] = masking_key[2];
          data_frame_head[5] = masking_key[3];
          data_frame_head_len = 6;
      }
      else if (payloadSize < 65536) {
          data_frame_head = (char *)flb_malloc(8);
          if (!data_frame_head) {
              flb_errno();
              return -1;
          }
          data_frame_head[0] = 0x81;
          data_frame_head[1] = 126 | 0x80;
          data_frame_head[2] = (payloadSize >> 8) & 0xff;
          data_frame_head[3] = (payloadSize >> 0) & 0xff;
          data_frame_head[4] = masking_key[0];
          data_frame_head[5] = masking_key[1];
          data_frame_head[6] = masking_key[2];
          data_frame_head[7] = masking_key[3];
          data_frame_head_len = 8;
      }
      else {
          data_frame_head = (char *)flb_malloc(14);
          if (!data_frame_head) {
              flb_errno();
              return -1;
          }
          data_frame_head[0] = 0x81;
          data_frame_head[1] = 127 | 0x80;
          data_frame_head[2] = (payloadSize >> 56) & 0xff;
          data_frame_head[3] = (payloadSize >> 48) & 0xff;
          data_frame_head[4] = (payloadSize >> 40) & 0xff;
          data_frame_head[5] = (payloadSize >> 32) & 0xff;
          data_frame_head[6] = (payloadSize >> 24) & 0xff;
          data_frame_head[7] = (payloadSize >> 16) & 0xff;
          data_frame_head[8] = (payloadSize >>  8) & 0xff;
          data_frame_head[9] = (payloadSize >>  0) & 0xff;
          data_frame_head[10] = masking_key[0];
          data_frame_head[11] = masking_key[1];
          data_frame_head[12] = masking_key[2];
          data_frame_head[13] = masking_key[3];
          data_frame_head_len = 14;
      }
      ret = flb_io_net_write(u_conn, data_frame_head, data_frame_head_len, &bytes_sent);
      if (ret == -1) {
          flb_error("[out_ws] could not write dataframe header");
          goto error;
      }
      flb_free(data_frame_head);
      return 0;
  
  error:
      flb_free(data_frame_head);
      return -1;
  }
  
  static int cb_ws_init(struct flb_output_instance *ins,
                        struct flb_config *config, void *data)
  {
      struct flb_out_ws *ctx = NULL;
  
      ctx = flb_ws_conf_create(ins, config);
      if (!ctx) {
          return -1;
      }
  
      ctx->handshake = 1;
      ctx->last_input_timestamp = time(NULL);
      flb_output_set_context(ins, ctx);
      return 0;
  }
  
  static int cb_ws_exit(void *data, struct flb_config *config)
  {
      struct flb_out_ws *ctx = data;
      flb_ws_conf_destroy(ctx);
      return 0;
  }
  
  static void cb_ws_flush(const void *data, size_t bytes,
                          const char *tag, int tag_len,
                          struct flb_input_instance *i_ins,
                          void *out_context,
                          struct flb_config *config)
  {
      int ret = -1;
      size_t bytes_sent;
      flb_sds_t json = NULL;
      struct flb_upstream *u;
      struct flb_upstream_conn *u_conn;
      struct flb_out_ws *ctx = out_context;
      time_t now;
  
      /* Get upstream context and connection */
      u = ctx->u;
      u_conn = flb_upstream_conn_get(u);
  
      if (!u_conn) {
          flb_error("[out_ws] no upstream connections available to %s:%i", u->tcp_host, u->tcp_port);
          ctx->handshake = 1;
          FLB_OUTPUT_RETURN(FLB_RETRY);
      }
  
      now = time(NULL);
  
      //TODO how to determine the interval? conn disconnet is about 30 sec, so we set 20 ssecnds here.
      flb_debug("[out_ws] interval is  %ld and handshake is %d", now - ctx->last_input_timestamp, ctx->handshake);
      if ((now - ctx->last_input_timestamp > ctx->idle_interval) && (ctx->handshake == 0)) {
          ctx->handshake = 1;
          flb_upstream_conn_release(u_conn);
          FLB_OUTPUT_RETURN(FLB_RETRY);
      }
      ctx->last_input_timestamp = now;
  
      if (ctx->handshake == 1) {
          /* Handshake with websocket server*/
          flb_info("[out_ws] handshake for ws");
          ret = flb_ws_handshake(u_conn, ctx);
          if (ret == -1) {
              flb_upstream_conn_release(u_conn);
              FLB_OUTPUT_RETURN(FLB_RETRY);
          }
          ctx->handshake = 0;
      }
  
      /* Data format process*/
      if (ctx->out_format != FLB_PACK_JSON_FORMAT_NONE) {
          json = flb_pack_msgpack_to_json_format(data, bytes,
                                                 ctx->out_format,
                                                 ctx->json_date_format,
                                                 ctx->json_date_key);
  
          if (!json) {
              flb_error("[out_ws] error formatting JSON payload");
              flb_upstream_conn_release(u_conn);
              FLB_OUTPUT_RETURN(FLB_ERROR);
          }
      }
  
      /* Write message header */
      if (ctx->out_format == FLB_PACK_JSON_FORMAT_NONE) {
          ret = flb_ws_sendDataFrameHeader(u_conn, ctx, data, bytes);
      }
      else {
          ret = flb_ws_sendDataFrameHeader(u_conn, ctx, json, flb_sds_len(json));
      }
  
      if (ret == -1) {
          flb_error("[out_ws] dataFrameHeader sent failed");
          ctx->handshake = 1;
          if (json) {
              flb_sds_destroy(json);
          }
          flb_upstream_conn_release(u_conn);
          FLB_OUTPUT_RETURN(FLB_RETRY);
      }
  
      /* Write message body*/
      if (ctx->out_format == FLB_PACK_JSON_FORMAT_NONE) {
          ret = flb_io_net_write(u_conn, data, bytes, &bytes_sent);
      }
      else {
          ret = flb_io_net_write(u_conn, json, flb_sds_len(json), &bytes_sent);
          flb_sds_destroy(json);
      }
  
      //flb_info("[out_ws] sendDataFrame number of bytes sent = %i", ret);
      if (ret == -1) {
          ctx->handshake = 1;
          flb_upstream_conn_release(u_conn);
          FLB_OUTPUT_RETURN(FLB_RETRY);
      }
  
      /* Release the connection */
      flb_upstream_conn_release(u_conn);
      FLB_OUTPUT_RETURN(FLB_OK);
  }
  
  /* Configuration properties map */
  static struct flb_config_map config_map[] = {
      {
       FLB_CONFIG_MAP_STR, "uri", NULL,
       0, FLB_TRUE, offsetof(struct flb_out_ws, uri),
       "Specify an optional URI for the target web socket server, e.g: /something"
      },
      {
       FLB_CONFIG_MAP_STR, "format", NULL,
       0, FLB_FALSE, 0,
       "Set desired payload format: json, json_stream, json_lines, gelf or msgpack"
      },
      /* EOF */
      {0}
  };
  
  /* Plugin reference */
  struct flb_output_plugin out_websocket_plugin = {
      .name         = "websocket",
      .description  = "Websocket",
      .cb_init      = cb_ws_init,
      .cb_flush     = cb_ws_flush,
      .cb_exit      = cb_ws_exit,
      .config_map   = config_map,
      .flags        = FLB_OUTPUT_NET | FLB_IO_OPT_TLS,
  };
  