websocket.c

/*
 * Copyright (c) 2013-2014 Intel Corporation, All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.

Authors:
        Wang, Jing J <jing.j.wang@intel.com>
*/

#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdarg.h>
#include <ctype.h>
#include <dlfcn.h>
#include "mongoose.h"

#include <sys/wait.h>
#include <unistd.h>
#include <sys/stat.h>

// Arguments:
//   flags: first byte of websocket frame, see websocket RFC,
//          http://tools.ietf.org/html/rfc6455, section 5.2
//   data, data_len: payload data. Mask, if any, is already applied.
static int websocket_data(struct mg_connection *conn, int flags,
                                  char *data, size_t data_len) {
  unsigned char reply[4];
  int offset = 2;
  int ret = 1;

//  (void) flags;

  // Truncate echoed message, to simplify output code.
  if (data_len > 65536) {
    data_len = 65536;
  }  
  printf("data_len=%d\n",data_len);
  int opcode = flags & 0x0f;
  if ((opcode == 0x08) || memcmp(data, ".close", 6)==0){
//    printf("close frame");
    reply[0] = 0x88; // close, FIN set
    reply[1] = data_len;
    // Status code
    if (data_len == 0){
      reply[2] = 3;
      reply[3] = 232;
    }else{
      reply[2] = data[0];
      reply[3] = data[1];
    }
    ret = 0;
  } else {
    reply[0] = 0x80|opcode;  // FIN set
    if (data_len <= 125){
      reply[1] = data_len;
    }
    else{
      reply[1] = 126;
      reply[2] = data_len / 256;
      reply[3] = data_len % 256;
      offset = 4;
    }
  }
  // Echo the message back to the client
  mg_write(conn, reply, offset);
  if (data_len > 0)
    mg_write(conn, data, data_len);
  // Returning zero means stoping websocket conversation.
  // Close the conversation if client has sent us "exit" string.
  return ret;
}

void websocket_ready_handler(struct mg_connection *conn){
  const char *prot = mg_get_header(conn, "Sec-WebSocket-Protocol");
  char buf[100];
  if (prot){
    char *p = NULL;
    snprintf(buf, sizeof(buf), "%s", prot);
    if ((p = strrchr(buf, ',')) != NULL) {
      *p = '\0';
    } 
    mg_printf(conn, "Sec-WebSocket-Protocol: %s\r\n", buf);
  }
  mg_printf(conn, "\r\n");
}


// Arguments:
//   flags: first byte of websocket frame, see websocket RFC,
//          http://tools.ietf.org/html/rfc6455, section 5.2
//   data, data_len: payload data. Mask, if any, is already applied.
int websocket_data_handler(struct mg_connection *conn, int flags,
                                  char *data, size_t data_len){
  const char *prot = mg_get_header(conn, "Sec-WebSocket-Protocol");
  if (prot && (strncmp(prot, "foobar", 6) == 0)){
    return 0;
  }
  const char *uri = mg_get_request_info(conn)->uri;
  if (strcmp(uri, "/") == 0 || strcmp(uri, "/echo") == 0){
      return websocket_data(conn, flags, data, data_len);
  }
  return 0; 
}