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 /*
  * Copyright (c) 2004-2013 Sergey Lyubka
  * Copyright (c) 2013-2015 Cesanta Software Limited
  * All rights reserved
  *
  * This software is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http://www.gnu.org/licenses/>.
  *
  * You are free to use this software under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this software under a commercial
  * license, as set out in <https://www.cesanta.com/license>.
  */
 
 #ifndef CS_MONGOOSE_SRC_COMMON_H_
 #define CS_MONGOOSE_SRC_COMMON_H_
 
 #define MG_VERSION "6.4"
 
 /* Local tweaks, applied before any of Mongoose's own headers. */
 #ifdef MG_LOCALS
 #include <mg_locals.h>
 #endif
 
 #if defined(MG_ENABLE_DEBUG) && !defined(CS_ENABLE_DEBUG)
 #define CS_ENABLE_DEBUG
 #endif
 #if defined(MG_DISABLE_STDIO) && !defined(CS_DISABLE_STDIO)
 #define CS_DISABLE_STDIO
 #elif defined(CS_DISABLE_STDIO) && !defined(MG_DISABLE_STDIO)
 #define MG_DISABLE_STDIO
 #endif
 
 /* All of the below features depend on filesystem access, disable them. */
 #ifdef MG_DISABLE_FILESYSTEM
 #ifndef MG_DISABLE_DAV
 #define MG_DISABLE_DAV
 #endif
 #ifndef MG_DISABLE_CGI
 #define MG_DISABLE_CGI
 #endif
 #ifndef MG_DISABLE_DIRECTORY_LISTING
 #define MG_DISABLE_DIRECTORY_LISTING
 #endif
 #ifndef MG_DISABLE_DAV
 #define MG_DISABLE_DAV
 #endif
 #endif /* MG_DISABLE_FILESYSTEM */
 
 #ifdef MG_NO_BSD_SOCKETS
 #ifndef MG_DISABLE_SYNC_RESOLVER
 #define MG_DISABLE_SYNC_RESOLVER
 #endif
 #ifndef MG_DISABLE_SOCKETPAIR
 #define MG_DISABLE_SOCKETPAIR
 #endif
 #endif /* MG_NO_BSD_SOCKETS */
 
 
 #endif /* CS_MONGOOSE_SRC_COMMON_H_ */
 #ifndef CS_COMMON_PLATFORM_H_
 #define CS_COMMON_PLATFORM_H_
 
 /*
  * For the "custom" platform, includes and dependencies can be
  * provided through mg_locals.h.
  */
 #define CS_P_CUSTOM 0
 #define CS_P_UNIX 1
 #define CS_P_WINDOWS 2
 #define CS_P_ESP_LWIP 3
 #define CS_P_CC3200 4
 #define CS_P_MSP432 5
 
 /* If not specified explicitly, we guess platform by defines. */
 #ifndef CS_PLATFORM
 
 #if defined(TARGET_IS_MSP432P4XX) || defined(__MSP432P401R__)
 
 #define CS_PLATFORM CS_P_MSP432
 #elif defined(cc3200)
 #define CS_PLATFORM CS_P_CC3200
 #elif defined(__unix__) || defined(__APPLE__)
 #define CS_PLATFORM CS_P_UNIX
 #elif defined(_WIN32)
 #define CS_PLATFORM CS_P_WINDOWS
 #endif
 
 #ifndef CS_PLATFORM
 #error "CS_PLATFORM is not specified and we couldn't guess it."
 #endif
 
 #endif /* !defined(CS_PLATFORM) */
 
 
 /* Common stuff */
 
 #ifdef __GNUC__
 #define NORETURN __attribute__((noreturn))
 #define NOINLINE __attribute__((noinline))
 #define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 #else
 #define NORETURN
 #define NOINLINE
 #define WARN_UNUSED_RESULT
 #endif /* __GNUC__ */
 
 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
 #endif
 
 #endif /* CS_COMMON_PLATFORM_H_ */
 #ifndef CS_COMMON_PLATFORMS_PLATFORM_WINDOWS_H_
 #define CS_COMMON_PLATFORMS_PLATFORM_WINDOWS_H_
 #if CS_PLATFORM == CS_P_WINDOWS
 
 /*
  * MSVC++ 14.0 _MSC_VER == 1900 (Visual Studio 2015)
  * MSVC++ 12.0 _MSC_VER == 1800 (Visual Studio 2013)
  * MSVC++ 11.0 _MSC_VER == 1700 (Visual Studio 2012)
  * MSVC++ 10.0 _MSC_VER == 1600 (Visual Studio 2010)
  * MSVC++ 9.0  _MSC_VER == 1500 (Visual Studio 2008)
  * MSVC++ 8.0  _MSC_VER == 1400 (Visual Studio 2005)
  * MSVC++ 7.1  _MSC_VER == 1310 (Visual Studio 2003)
  * MSVC++ 7.0  _MSC_VER == 1300
  * MSVC++ 6.0  _MSC_VER == 1200
  * MSVC++ 5.0  _MSC_VER == 1100
  */
 #ifdef _MSC_VER
 #pragma warning(disable : 4127) /* FD_SET() emits warning, disable it */
 #pragma warning(disable : 4204) /* missing c99 support */
 #endif
 
 #include <assert.h>
 #include <direct.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <io.h>
 #include <limits.h>
 #include <signal.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <time.h>
 
 #define random() rand()
 #ifdef _MSC_VER
 #pragma comment(lib, "ws2_32.lib") /* Linking with winsock library */
 #endif
 
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <windows.h>
 #include <process.h>
 
 #ifndef EINPROGRESS
 #define EINPROGRESS WSAEINPROGRESS
 #endif
 #ifndef EWOULDBLOCK
 #define EWOULDBLOCK WSAEWOULDBLOCK
 #endif
 #ifndef __func__
 #define STRX(x) #x
 #define STR(x) STRX(x)
 #define __func__ __FILE__ ":" STR(__LINE__)
 #endif
 #define snprintf _snprintf
 #define fileno _fileno
 #define vsnprintf _vsnprintf
 #define sleep(x) Sleep((x) *1000)
 #define to64(x) _atoi64(x)
 #if !defined(__MINGW32__) && !defined(__MINGW64__)
 #define popen(x, y) _popen((x), (y))
 #define pclose(x) _pclose(x)
 #endif
 #define rmdir _rmdir
 #if defined(_MSC_VER) && _MSC_VER >= 1400
 #define fseeko(x, y, z) _fseeki64((x), (y), (z))
 #else
 #define fseeko(x, y, z) fseek((x), (y), (z))
 #endif
 #define random() rand()
 typedef int socklen_t;
 #if _MSC_VER >= 1700
 #include <stdint.h>
 #else
 typedef signed char int8_t;
 typedef unsigned char uint8_t;
 typedef int int32_t;
 typedef unsigned int uint32_t;
 typedef short int16_t;
 typedef unsigned short uint16_t;
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
 #endif
 typedef SOCKET sock_t;
 typedef uint32_t in_addr_t;
 #ifndef UINT16_MAX
 #define UINT16_MAX 65535
 #endif
 #ifndef UINT32_MAX
 #define UINT32_MAX 4294967295
 #endif
 #ifndef pid_t
 #define pid_t HANDLE
 #endif
 #define INT64_FMT "I64d"
 #define INT64_X_FMT "I64x"
 #define SIZE_T_FMT "Iu"
 #if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
 typedef struct stat cs_stat_t;
 #else
 typedef struct _stati64 cs_stat_t;
 #endif
 #ifndef S_ISDIR
 #define S_ISDIR(x) (((x) &_S_IFMT) == _S_IFDIR)
 #endif
 #ifndef S_ISREG
 #define S_ISREG(x) (((x) &_S_IFMT) == _S_IFREG)
 #endif
 #define DIRSEP '\\'
 
 #ifndef va_copy
 #ifdef __va_copy
 #define va_copy __va_copy
 #else
 #define va_copy(x, y) (x) = (y)
 #endif
 #endif
 
 #ifndef MG_MAX_HTTP_REQUEST_SIZE
 #define MG_MAX_HTTP_REQUEST_SIZE 8192
 #endif
 
 #ifndef MG_MAX_HTTP_SEND_MBUF
 #define MG_MAX_HTTP_SEND_MBUF 4096
 #endif
 
 #ifndef MG_MAX_HTTP_HEADERS
 #define MG_MAX_HTTP_HEADERS 40
 #endif
 
 #endif /* CS_PLATFORM == CS_P_WINDOWS */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_WINDOWS_H_ */
 #ifndef CS_COMMON_PLATFORMS_PLATFORM_UNIX_H_
 #define CS_COMMON_PLATFORMS_PLATFORM_UNIX_H_
 #if CS_PLATFORM == CS_P_UNIX
 
 #ifndef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 600
 #endif
 
 /* <inttypes.h> wants this for C++ */
 #ifndef __STDC_FORMAT_MACROS
 #define __STDC_FORMAT_MACROS
 #endif
 
 /* C++ wants that for INT64_MAX */
 #ifndef __STDC_LIMIT_MACROS
 #define __STDC_LIMIT_MACROS
 #endif
 
 /* Enable fseeko() and ftello() functions */
 #ifndef _LARGEFILE_SOURCE
 #define _LARGEFILE_SOURCE
 #endif
 
 /* Enable 64-bit file offsets */
 #ifndef _FILE_OFFSET_BITS
 #define _FILE_OFFSET_BITS 64
 #endif
 
 #include <arpa/inet.h>
 #include <assert.h>
 #include <ctype.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <limits.h>
 #include <math.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/select.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 /*
  * osx correctly avoids defining strtoll when compiling in strict ansi mode.
  * We require strtoll, and if your embedded pre-c99 compiler lacks one, please
  * implement a shim.
  */
 #if !(defined(__DARWIN_C_LEVEL) && __DARWIN_C_LEVEL >= 200809L)
 long long strtoll(const char *, char **, int);
 #endif
 
 typedef int sock_t;
 #define INVALID_SOCKET (-1)
 #define SIZE_T_FMT "zu"
 typedef struct stat cs_stat_t;
 #define DIRSEP '/'
 #define to64(x) strtoll(x, NULL, 10)
 #define INT64_FMT PRId64
 #define INT64_X_FMT PRIx64
 
 #ifndef __cdecl
 #define __cdecl
 #endif
 
 #ifndef va_copy
 #ifdef __va_copy
 #define va_copy __va_copy
 #else
 #define va_copy(x, y) (x) = (y)
 #endif
 #endif
 
 #define closesocket(x) close(x)
 
 #ifndef MG_MAX_HTTP_REQUEST_SIZE
 #define MG_MAX_HTTP_REQUEST_SIZE 8192
 #endif
 
 #ifndef MG_MAX_HTTP_SEND_MBUF
 #define MG_MAX_HTTP_SEND_MBUF 4096
 #endif
 
 #ifndef MG_MAX_HTTP_HEADERS
 #define MG_MAX_HTTP_HEADERS 40
 #endif
 
 #endif /* CS_PLATFORM == CS_P_UNIX */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_UNIX_H_ */
 #ifndef CS_COMMON_PLATFORMS_PLATFORM_ESP_LWIP_H_
 #define CS_COMMON_PLATFORMS_PLATFORM_ESP_LWIP_H_
 #if CS_PLATFORM == CS_P_ESP_LWIP
 
 #include <assert.h>
 #include <ctype.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 
 #include <lwip/err.h>
 #include <lwip/ip_addr.h>
 #include <lwip/inet.h>
 #include <lwip/netdb.h>
 #include <lwip/dns.h>
 
 #ifndef LWIP_PROVIDE_ERRNO
 #include <errno.h>
 #endif
 
 #define LWIP_TIMEVAL_PRIVATE 0
 
 #if LWIP_SOCKET
 #include <lwip/sockets.h>
 #define SOMAXCONN 10
 #else
 /* We really need the definitions from sockets.h. */
 #undef LWIP_SOCKET
 #define LWIP_SOCKET 1
 #include <lwip/sockets.h>
 #undef LWIP_SOCKET
 #define LWIP_SOCKET 0
 #endif
 
 typedef int sock_t;
 #define INVALID_SOCKET (-1)
 #define SIZE_T_FMT "u"
 typedef struct stat cs_stat_t;
 #define DIRSEP '/'
 #define to64(x) strtoll(x, NULL, 10)
 #define INT64_FMT PRId64
 #define INT64_X_FMT PRIx64
 #define __cdecl
 
 unsigned long os_random(void);
 #define random os_random
 
 #endif /* CS_PLATFORM == CS_P_ESP_LWIP */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_ESP_LWIP_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_PLATFORMS_PLATFORM_CC3200_H_
 #define CS_COMMON_PLATFORMS_PLATFORM_CC3200_H_
 #if CS_PLATFORM == CS_P_CC3200
 
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <inttypes.h>
 #include <stdint.h>
 #include <string.h>
 #include <time.h>
 
 #ifndef __TI_COMPILER_VERSION__
 #include <fcntl.h>
 #include <sys/time.h>
 #endif
 
 #define MG_SOCKET_SIMPLELINK 1
 #define MG_DISABLE_SOCKETPAIR 1
 #define MG_DISABLE_SYNC_RESOLVER 1
 #define MG_DISABLE_POPEN 1
 #define MG_DISABLE_CGI 1
 /* Only SPIFFS supports directories, SLFS does not. */
 #ifndef CC3200_FS_SPIFFS
 #define MG_DISABLE_DAV 1
 #define MG_DISABLE_DIRECTORY_LISTING 1
 #endif
 
 
 typedef int sock_t;
 #define INVALID_SOCKET (-1)
 #define SIZE_T_FMT "u"
 typedef struct stat cs_stat_t;
 #define DIRSEP '/'
 #define to64(x) strtoll(x, NULL, 10)
 #define INT64_FMT PRId64
 #define INT64_X_FMT PRIx64
 #define __cdecl
 
 #define fileno(x) -1
 
 /* Some functions we implement for Mongoose. */
 
 #ifdef __cplusplus
 extern "C" {
 #endif
    
 #ifdef __TI_COMPILER_VERSION__
    struct SlTimeval_t;
 #define timeval SlTimeval_t
    int gettimeofday(struct timeval *t, void *tz);
    
    int asprintf(char **strp, const char *fmt, ...);
    
 #endif
    
    long int random(void);
    
    /* TI's libc does not have stat & friends, add them. */
 #ifdef __TI_COMPILER_VERSION__
    
 #include <file.h>
    
    typedef unsigned int mode_t;
    typedef size_t _off_t;
    typedef long ssize_t;
    
    struct stat {
       int st_ino;
       mode_t st_mode;
       int st_nlink;
       time_t st_mtime;
       off_t st_size;
    };
    
    int _stat(const char *pathname, struct stat *st);
 #define stat(a, b) _stat(a, b)
    
 #define __S_IFMT 0170000
    
 #define __S_IFDIR 0040000
 #define __S_IFCHR 0020000
 #define __S_IFREG 0100000
    
 #define __S_ISTYPE(mode, mask) (((mode) &__S_IFMT) == (mask))
    
 #define S_IFDIR __S_IFDIR
 #define S_IFCHR __S_IFCHR
 #define S_IFREG __S_IFREG
 #define S_ISDIR(mode) __S_ISTYPE((mode), __S_IFDIR)
 #define S_ISREG(mode) __S_ISTYPE((mode), __S_IFREG)
    
    /* As of 5.2.7, TI compiler does not support va_copy() yet. */
 #define va_copy(apc, ap) ((apc) = (ap))
    
 #endif /* __TI_COMPILER_VERSION__ */
    
 #ifdef CC3200_FS_SPIFFS
 #include <common/spiffs/spiffs.h>
    
    typedef struct {
       spiffs_DIR dh;
       struct spiffs_dirent de;
    } DIR;
    
 #define d_name name
 #define dirent spiffs_dirent
    
    DIR *opendir(const char *dir_name);
    int closedir(DIR *dir);
    struct dirent *readdir(DIR *dir);
 #endif /* CC3200_FS_SPIFFS */
    
 #ifdef CC3200_FS_SLFS
 #define MG_FS_SLFS
 #endif
    
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* CS_PLATFORM == CS_P_CC3200 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_CC3200_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_PLATFORMS_PLATFORM_MSP432_H_
 #define CS_COMMON_PLATFORMS_PLATFORM_MSP432_H_
 #if CS_PLATFORM == CS_P_MSP432
 
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <inttypes.h>
 #include <stdint.h>
 #include <string.h>
 #include <time.h>
 
 #ifndef __TI_COMPILER_VERSION__
 #include <fcntl.h>
 #include <sys/time.h>
 #endif
 
 #define MG_SOCKET_SIMPLELINK 1
 #define MG_DISABLE_SOCKETPAIR 1
 #define MG_DISABLE_SYNC_RESOLVER 1
 #define MG_DISABLE_POPEN 1
 #define MG_DISABLE_CGI 1
 #define MG_DISABLE_DAV 1
 #define MG_DISABLE_DIRECTORY_LISTING 1
 
 
 typedef int sock_t;
 #define INVALID_SOCKET (-1)
 #define SIZE_T_FMT "u"
 typedef struct stat cs_stat_t;
 #define DIRSEP '/'
 #define to64(x) strtoll(x, NULL, 10)
 #define INT64_FMT PRId64
 #define INT64_X_FMT PRIx64
 #define __cdecl
 
 #define fileno(x) -1
 
 /* Some functions we implement for Mongoose. */
 
 #ifdef __cplusplus
 extern "C" {
 #endif
    
 #ifdef __TI_COMPILER_VERSION__
    struct SlTimeval_t;
 #define timeval SlTimeval_t
    int gettimeofday(struct timeval *t, void *tz);
 #endif
    
    long int random(void);
    
    /* TI's libc does not have stat & friends, add them. */
 #ifdef __TI_COMPILER_VERSION__
    
 #include <file.h>
    
    typedef unsigned int mode_t;
    typedef size_t _off_t;
    typedef long ssize_t;
    
    struct stat {
       int st_ino;
       mode_t st_mode;
       int st_nlink;
       time_t st_mtime;
       off_t st_size;
    };
    
    int _stat(const char *pathname, struct stat *st);
 #define stat(a, b) _stat(a, b)
    
 #define __S_IFMT 0170000
    
 #define __S_IFDIR 0040000
 #define __S_IFCHR 0020000
 #define __S_IFREG 0100000
    
 #define __S_ISTYPE(mode, mask) (((mode) &__S_IFMT) == (mask))
    
 #define S_IFDIR __S_IFDIR
 #define S_IFCHR __S_IFCHR
 #define S_IFREG __S_IFREG
 #define S_ISDIR(mode) __S_ISTYPE((mode), __S_IFDIR)
 #define S_ISREG(mode) __S_ISTYPE((mode), __S_IFREG)
    
    /* As of 5.2.7, TI compiler does not support va_copy() yet. */
 #define va_copy(apc, ap) ((apc) = (ap))
    
 #endif /* __TI_COMPILER_VERSION__ */
    
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* CS_PLATFORM == CS_P_MSP432 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_MSP432_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_PLATFORMS_SIMPLELINK_CS_SIMPLELINK_H_
 #define CS_COMMON_PLATFORMS_SIMPLELINK_CS_SIMPLELINK_H_
 
 /* If simplelink.h is already included, all bets are off. */
 #if defined(MG_SOCKET_SIMPLELINK) && !defined(__SIMPLELINK_H__)
 
 #include <stdbool.h>
 
 #ifndef __TI_COMPILER_VERSION__
 #undef __CONCAT
 #undef FD_CLR
 #undef FD_ISSET
 #undef FD_SET
 #undef FD_SETSIZE
 #undef FD_ZERO
 #undef fd_set
 #endif
 
 /* We want to disable SL_INC_STD_BSD_API_NAMING, so we include user.h ourselves
  * and undef it. */
 #define PROVISIONING_API_H_
 #include <simplelink/user.h>
 #undef PROVISIONING_API_H_
 #undef SL_INC_STD_BSD_API_NAMING
 
 #include <simplelink/include/simplelink.h>
 
 /* Now define only the subset of the BSD API that we use.
  * Notably, close(), read() and write() are not defined. */
 #define AF_INET SL_AF_INET
 
 #define socklen_t SlSocklen_t
 #define sockaddr SlSockAddr_t
 #define sockaddr_in SlSockAddrIn_t
 #define in_addr SlInAddr_t
 
 #define SOCK_STREAM SL_SOCK_STREAM
 #define SOCK_DGRAM SL_SOCK_DGRAM
 
 #define FD_SET SL_FD_SET
 #define FD_CLR SL_FD_CLR
 #define FD_ISSET SL_FD_ISSET
 #define FD_ZERO SL_FD_ZERO
 #define fd_set SlFdSet_t
 
 #define htonl sl_Htonl
 #define ntohl sl_Ntohl
 #define htons sl_Htons
 #define ntohs sl_Ntohs
 
 #define accept sl_Accept
 #define closesocket sl_Close
 #define bind sl_Bind
 #define connect sl_Connect
 #define listen sl_Listen
 #define recv sl_Recv
 #define recvfrom sl_RecvFrom
 #define send sl_Send
 #define sendto sl_SendTo
 #define socket sl_Socket
 
 #define select(nfds, rfds, wfds, efds, tout) \
 sl_Select((nfds), (rfds), (wfds), (efds), (struct SlTimeval_t *)(tout))
 
 #ifndef EACCES
 #define EACCES SL_EACCES
 #endif
 #ifndef EAFNOSUPPORT
 #define EAFNOSUPPORT SL_EAFNOSUPPORT
 #endif
 #ifndef EAGAIN
 #define EAGAIN SL_EAGAIN
 #endif
 #ifndef EBADF
 #define EBADF SL_EBADF
 #endif
 #ifndef EINVAL
 #define EINVAL SL_EINVAL
 #endif
 #ifndef ENOMEM
 #define ENOMEM SL_ENOMEM
 #endif
 #ifndef EWOULDBLOCK
 #define EWOULDBLOCK SL_EWOULDBLOCK
 #endif
 
 #define SOMAXCONN 8
 
 #ifdef __cplusplus
 extern "C" {
 #endif
    
    const char *inet_ntop(int af, const void *src, char *dst, socklen_t size);
    char *inet_ntoa(struct in_addr in);
    int inet_pton(int af, const char *src, void *dst);
    
    struct mg_mgr;
    
    typedef void (*mg_init_cb)(struct mg_mgr *mgr);
    bool mg_start_task(int priority, int stack_size, mg_init_cb mg_init);
    
    void mg_run_in_task(void (*cb)(struct mg_mgr *mgr, void *arg), void *cb_arg);
    
    int sl_fs_init();
    
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* defined(MG_SOCKET_SIMPLELINK) && !defined(__SIMPLELINK_H__) */
 
 #endif /* CS_COMMON_PLATFORMS_SIMPLELINK_CS_SIMPLELINK_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_CS_DBG_H_
 #define CS_COMMON_CS_DBG_H_
 
 #ifndef CS_DISABLE_STDIO
 #include <stdio.h>
 #endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    enum cs_log_level {
       LL_NONE = -1,
       LL_ERROR = 0,
       LL_WARN = 1,
       LL_INFO = 2,
       LL_DEBUG = 3,
       LL_VERBOSE_DEBUG = 4,
       
       _LL_MIN = -2,
       _LL_MAX = 5,
    };
    
    void cs_log_set_level(enum cs_log_level level);
    
 #ifndef CS_DISABLE_STDIO
    
    void cs_log_set_file(FILE *file);
    
    extern enum cs_log_level cs_log_level;
    void cs_log_print_prefix(const char *func);
    void cs_log_printf(const char *fmt, ...);
    
 #define LOG(l, x)                  \
 if (cs_log_level >= l) {         \
 cs_log_print_prefix(__func__); \
 cs_log_printf x;               \
 }
    
 #ifndef CS_NDEBUG
    
 #define DBG(x)                            \
 if (cs_log_level >= LL_VERBOSE_DEBUG) { \
 cs_log_print_prefix(__func__);        \
 cs_log_printf x;                      \
 }
    
 #else /* NDEBUG */
    
 #define DBG(x)
    
 #endif
    
 #else /* CS_DISABLE_STDIO */
    
 #define LOG(l, x)
 #define DBG(x)
    
 #endif
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_COMMON_CS_DBG_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_CS_TIME_H_
 #define CS_COMMON_CS_TIME_H_
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /* Sub-second granularity time(). */
    double cs_time();
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_COMMON_CS_TIME_H_ */
 /*
  * Copyright (c) 2015 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === Memory Buffers
  *
  * Mbufs are mutable/growing memory buffers, like C++ strings.
  * Mbuf can append data to the end of a buffer, or insert data into arbitrary
  * position in the middle of a buffer. The buffer grows automatically when
  * needed.
  */
 
 #ifndef CS_COMMON_MBUF_H_
 #define CS_COMMON_MBUF_H_
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
    
 #include <stdlib.h>
    
 #ifndef MBUF_SIZE_MULTIPLIER
 #define MBUF_SIZE_MULTIPLIER 1.5
 #endif
    
    /* Memory buffer descriptor */
    struct mbuf {
       char *buf;   /* Buffer pointer */
       size_t len;  /* Data length. Data is located between offset 0 and len. */
       size_t size; /* Buffer size allocated by realloc(1). Must be >= len */
    };
    
    /*
     * Initialize an Mbuf.
     * `initial_capacity` specifies the initial capacity of the mbuf.
     */
    void mbuf_init(struct mbuf *, size_t initial_capacity);
    
    /* Free the space allocated for the mbuffer and resets the mbuf structure. */
    void mbuf_free(struct mbuf *);
    
    /*
     * Appends data to the Mbuf.
     *
     * Return the number of bytes appended, or 0 if out of memory.
     */
    size_t mbuf_append(struct mbuf *, const void *data, size_t data_size);
    
    /*
     * Insert data at a specified offset in the Mbuf.
     *
     * Existing data will be shifted forwards and the buffer will
     * be grown if necessary.
     * Return the number of bytes inserted.
     */
    size_t mbuf_insert(struct mbuf *, size_t, const void *, size_t);
    
    /* Remove `data_size` bytes from the beginning of the buffer. */
    void mbuf_remove(struct mbuf *, size_t data_size);
    
    /*
     * Resize an Mbuf.
     *
     * If `new_size` is smaller than buffer's `len`, the
     * resize is not performed.
     */
    void mbuf_resize(struct mbuf *, size_t new_size);
    
    /* Shrink an Mbuf by resizing its `size` to `len`. */
    void mbuf_trim(struct mbuf *);
    
 #if defined(__cplusplus)
 }
 #endif /* __cplusplus */
 
 #endif /* CS_COMMON_MBUF_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_SHA1_H_
 #define CS_COMMON_SHA1_H_
 
 #ifndef DISABLE_SHA1
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    typedef struct {
       uint32_t state[5];
       uint32_t count[2];
       unsigned char buffer[64];
    } cs_sha1_ctx;
    
    void cs_sha1_init(cs_sha1_ctx *);
    void cs_sha1_update(cs_sha1_ctx *, const unsigned char *data, uint32_t len);
    void cs_sha1_final(unsigned char digest[20], cs_sha1_ctx *);
    void cs_hmac_sha1(const unsigned char *key, size_t key_len,
                      const unsigned char *text, size_t text_len,
                      unsigned char out[20]);
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* DISABLE_SHA1 */
 
 #endif /* CS_COMMON_SHA1_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_MD5_H_
 #define CS_COMMON_MD5_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    typedef struct MD5Context {
       uint32_t buf[4];
       uint32_t bits[2];
       unsigned char in[64];
    } MD5_CTX;
    
    void MD5_Init(MD5_CTX *c);
    void MD5_Update(MD5_CTX *c, const unsigned char *data, size_t len);
    void MD5_Final(unsigned char *md, MD5_CTX *c);
    
    /*
     * Return stringified MD5 hash for NULL terminated list of pointer/length pairs.
     * A length should be specified as size_t variable.
     * Example:
     *
     *    char buf[33];
     *    cs_md5(buf, "foo", (size_t) 3, "bar", (size_t) 3, NULL);
     */
    char *cs_md5(char buf[33], ...);
    
    /*
     * Stringify binary data. Output buffer size must be 2 * size_of_input + 1
     * because each byte of input takes 2 bytes in string representation
     * plus 1 byte for the terminating \0 character.
     */
    void cs_to_hex(char *to, const unsigned char *p, size_t len);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_COMMON_MD5_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_BASE64_H_
 #define CS_COMMON_BASE64_H_
 
 #ifndef DISABLE_BASE64
 
 #include <stdio.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
    
    typedef void (*cs_base64_putc_t)(char, void *);
    
    struct cs_base64_ctx {
       /* cannot call it putc because it's a macro on some environments */
       cs_base64_putc_t b64_putc;
       unsigned char chunk[3];
       int chunk_size;
       void *user_data;
    };
    
    void cs_base64_init(struct cs_base64_ctx *ctx, cs_base64_putc_t putc,
                        void *user_data);
    void cs_base64_update(struct cs_base64_ctx *ctx, const char *str, size_t len);
    void cs_base64_finish(struct cs_base64_ctx *ctx);
    
    void cs_base64_encode(const unsigned char *src, int src_len, char *dst);
    void cs_fprint_base64(FILE *f, const unsigned char *src, int src_len);
    int cs_base64_decode(const unsigned char *s, int len, char *dst);
    
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* DISABLE_BASE64 */
 
 #endif /* CS_COMMON_BASE64_H_ */
 /*
  * Copyright (c) 2015 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_COMMON_STR_UTIL_H_
 #define CS_COMMON_STR_UTIL_H_
 
 #include <stdarg.h>
 #include <stdlib.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
    
    size_t c_strnlen(const char *s, size_t maxlen);
    int c_snprintf(char *buf, size_t buf_size, const char *format, ...);
    int c_vsnprintf(char *buf, size_t buf_size, const char *format, va_list ap);
    /*
     * Find the first occurrence of find in s, where the search is limited to the
     * first slen characters of s.
     */
    const char *c_strnstr(const char *s, const char *find, size_t slen);
    
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* CS_COMMON_STR_UTIL_H_ */
 /*
  * Copyright (c) 2004-2013 Sergey Lyubka <valenok@gmail.com>
  * Copyright (c) 2013 Cesanta Software Limited
  * All rights reserved
  *
  * This library is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http: *www.gnu.org/licenses/>.
  *
  * You are free to use this library under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this library under a commercial
  * license, as set out in <http://cesanta.com/products.html>.
  */
 
 #ifndef CS_MONGOOSE_DEPS_FROZEN_FROZEN_H_
 #define CS_MONGOOSE_DEPS_FROZEN_FROZEN_H_
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #include <stdarg.h>
    
    enum json_type {
       JSON_TYPE_EOF = 0, /* End of parsed tokens marker */
       JSON_TYPE_STRING = 1,
       JSON_TYPE_NUMBER = 2,
       JSON_TYPE_OBJECT = 3,
       JSON_TYPE_TRUE = 4,
       JSON_TYPE_FALSE = 5,
       JSON_TYPE_NULL = 6,
       JSON_TYPE_ARRAY = 7
    };
    
    struct json_token {
       const char *ptr;     /* Points to the beginning of the token */
       int len;             /* Token length */
       int num_desc;        /* For arrays and object, total number of descendants */
       enum json_type type; /* Type of the token, possible values above */
    };
    
    /* Error codes */
 #define JSON_STRING_INVALID -1
 #define JSON_STRING_INCOMPLETE -2
 #define JSON_TOKEN_ARRAY_TOO_SMALL -3
    
    int parse_json(const char *json_string, int json_string_length,
                   struct json_token *tokens_array, int size_of_tokens_array);
    struct json_token *parse_json2(const char *json_string, int string_length);
    struct json_token *find_json_token(struct json_token *toks, const char *path);
    
    int json_emit_long(char *buf, int buf_len, long value);
    int json_emit_double(char *buf, int buf_len, double value);
    int json_emit_quoted_str(char *buf, int buf_len, const char *str, int len);
    int json_emit_unquoted_str(char *buf, int buf_len, const char *str, int len);
    int json_emit(char *buf, int buf_len, const char *fmt, ...);
    int json_emit_va(char *buf, int buf_len, const char *fmt, va_list);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_MONGOOSE_DEPS_FROZEN_FROZEN_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  * This software is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http://www.gnu.org/licenses/>.
  *
  * You are free to use this software under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this software under a commercial
  * license, as set out in <https://www.cesanta.com/license>.
  */
 
 /*
  * === Core: TCP/UDP/SSL
  *
  * NOTE: Mongoose manager is single threaded. It does not protect
  * its data structures by mutexes, therefore all functions that are dealing
  * with particular event manager should be called from the same thread,
  * with exception of `mg_broadcast()` function. It is fine to have different
  * event managers handled by different threads.
  */
 
 #ifndef CS_MONGOOSE_SRC_NET_H_
 #define CS_MONGOOSE_SRC_NET_H_
 
 #ifdef MG_ENABLE_JAVASCRIPT
 #define EXCLUDE_COMMON
 #include <v7.h>
 #endif
 
 
 #ifdef MG_ENABLE_SSL
 #ifdef __APPLE__
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
 #include <openssl/ssl.h>
 #else
 typedef void *SSL;
 typedef void *SSL_CTX;
 #endif
 
 #ifndef MG_VPRINTF_BUFFER_SIZE
 #define MG_VPRINTF_BUFFER_SIZE 100
 #endif
 
 #ifdef MG_USE_READ_WRITE
 #define MG_RECV_FUNC(s, b, l, f) read(s, b, l)
 #define MG_SEND_FUNC(s, b, l, f) write(s, b, l)
 #else
 #define MG_RECV_FUNC(s, b, l, f) recv(s, b, l, f)
 #define MG_SEND_FUNC(s, b, l, f) send(s, b, l, f)
 #endif
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    union socket_address {
       struct sockaddr sa;
       struct sockaddr_in sin;
 #ifdef MG_ENABLE_IPV6
       struct sockaddr_in6 sin6;
 #else
       struct sockaddr sin6;
 #endif
    };
    
    /* Describes chunk of memory */
    struct mg_str {
       const char *p; /* Memory chunk pointer */
       size_t len;    /* Memory chunk length */
    };
    
    struct mg_connection;
    
    /*
     * Callback function (event handler) prototype, must be defined by user.
     * Mongoose calls event handler, passing events defined below.
     */
    typedef void (*mg_event_handler_t)(struct mg_connection *, int ev, void *);
    
    /* Events. Meaning of event parameter (evp) is given in the comment. */
 #define MG_EV_POLL 0    /* Sent to each connection on each mg_mgr_poll() call */
 #define MG_EV_ACCEPT 1  /* New connection accepted. union socket_address * */
 #define MG_EV_CONNECT 2 /* connect() succeeded or failed. int *  */
 #define MG_EV_RECV 3    /* Data has benn received. int *num_bytes */
 #define MG_EV_SEND 4    /* Data has been written to a socket. int *num_bytes */
 #define MG_EV_CLOSE 5   /* Connection is closed. NULL */
 #define MG_EV_TIMER 6   /* now >= conn->ev_timer_time. double * */
    
    /*
     * Mongoose event manager.
     */
    struct mg_mgr {
       struct mg_connection *active_connections;
       const char *hexdump_file; /* Debug hexdump file path */
 #ifndef MG_DISABLE_SOCKETPAIR
       sock_t ctl[2]; /* Socketpair for mg_wakeup() */
 #endif
       void *user_data; /* User data */
       void *mgr_data;  /* Implementation-specific event manager's data. */
 #ifdef MG_ENABLE_JAVASCRIPT
       struct v7 *v7;
 #endif
    };
    
    /*
     * Mongoose connection.
     */
    struct mg_connection {
       struct mg_connection *next, *prev; /* mg_mgr::active_connections linkage */
       struct mg_connection *listener;    /* Set only for accept()-ed connections */
       struct mg_mgr *mgr;                /* Pointer to containing manager */
       
       sock_t sock; /* Socket to the remote peer */
       int err;
       union socket_address sa; /* Remote peer address */
       size_t recv_mbuf_limit;  /* Max size of recv buffer */
       struct mbuf recv_mbuf;   /* Received data */
       struct mbuf send_mbuf;   /* Data scheduled for sending */
       SSL *ssl;
       SSL_CTX *ssl_ctx;
       time_t last_io_time;              /* Timestamp of the last socket IO */
       double ev_timer_time;             /* Timestamp of the future MG_EV_TIMER */
       mg_event_handler_t proto_handler; /* Protocol-specific event handler */
       void *proto_data;                 /* Protocol-specific data */
       void (*proto_data_destructor)(void *proto_data);
       mg_event_handler_t handler; /* Event handler function */
       void *user_data;            /* User-specific data */
       union {
          void *v;
          /*
           * the C standard is fussy about fitting function pointers into
           * void pointers, since some archs might have fat pointers for functions.
           */
          mg_event_handler_t f;
       } priv_1;       /* Used by mg_enable_multithreading() */
       void *priv_2;   /* Used by mg_enable_multithreading() */
       void *mgr_data; /* Implementation-specific event manager's data. */
       unsigned long flags;
       /* Flags set by Mongoose */
 #define MG_F_LISTENING (1 << 0)          /* This connection is listening */
 #define MG_F_UDP (1 << 1)                /* This connection is UDP */
 #define MG_F_RESOLVING (1 << 2)          /* Waiting for async resolver */
 #define MG_F_CONNECTING (1 << 3)         /* connect() call in progress */
 #define MG_F_SSL_HANDSHAKE_DONE (1 << 4) /* SSL specific */
 #define MG_F_WANT_READ (1 << 5)          /* SSL specific */
 #define MG_F_WANT_WRITE (1 << 6)         /* SSL specific */
 #define MG_F_IS_WEBSOCKET (1 << 7)       /* Websocket specific */
       
       /* Flags that are settable by user */
 #define MG_F_SEND_AND_CLOSE (1 << 10)      /* Push remaining data and close  */
 #define MG_F_CLOSE_IMMEDIATELY (1 << 11)   /* Disconnect */
 #define MG_F_WEBSOCKET_NO_DEFRAG (1 << 12) /* Websocket specific */
 #define MG_F_DELETE_CHUNK (1 << 13)        /* HTTP specific */
       
 #define MG_F_USER_1 (1 << 20) /* Flags left for application */
 #define MG_F_USER_2 (1 << 21)
 #define MG_F_USER_3 (1 << 22)
 #define MG_F_USER_4 (1 << 23)
 #define MG_F_USER_5 (1 << 24)
 #define MG_F_USER_6 (1 << 25)
    };
    
    /*
     * Initialize Mongoose manager. Side effect: ignores SIGPIPE signal.
     * `mgr->user_data` field will be initialized with `user_data` parameter.
     * That is an arbitrary pointer, where user code can associate some data
     * with the particular Mongoose manager. For example, a C++ wrapper class
     * could be written, in which case `user_data` can hold a pointer to the
     * class instance.
     */
    void mg_mgr_init(struct mg_mgr *mgr, void *user_data);
    
    /*
     * De-initializes Mongoose manager.
     *
     * Close and deallocate all active connections.
     */
    void mg_mgr_free(struct mg_mgr *);
    
    /*
     * This function performs the actual IO, and must be called in a loop
     * (an event loop). Returns the current timestamp.
     * `milli` is the maximum number of milliseconds to sleep.
     * `mg_mgr_poll()` checks all connection for IO readiness. If at least one
     * of the connections is IO-ready, `mg_mgr_poll()` triggers respective
     * event handlers and returns.
     */
    time_t mg_mgr_poll(struct mg_mgr *, int milli);
    
 #ifndef MG_DISABLE_SOCKETPAIR
    /*
     * Pass a message of a given length to all connections.
     *
     * Must be called from a thread that does NOT call `mg_mgr_poll()`.
     * Note that `mg_broadcast()` is the only function
     * that can be, and must be, called from a different (non-IO) thread.
     *
     * `func` callback function will be called by the IO thread for each
     * connection. When called, event would be `MG_EV_POLL`, and message will
     * be passed as `ev_data` pointer. Maximum message size is capped
     * by `MG_CTL_MSG_MESSAGE_SIZE` which is set to 8192 bytes.
     */
    void mg_broadcast(struct mg_mgr *, mg_event_handler_t func, void *, size_t);
 #endif
    
    /*
     * Iterate over all active connections.
     *
     * Returns next connection from the list
     * of active connections, or `NULL` if there is no more connections. Below
     * is the iteration idiom:
     *
     * ```c
     * for (c = mg_next(srv, NULL); c != NULL; c = mg_next(srv, c)) {
     *   // Do something with connection `c`
     * }
     * ```
     */
    struct mg_connection *mg_next(struct mg_mgr *, struct mg_connection *);
    
    /*
     * Optional parameters to `mg_add_sock_opt()`.
     *
     * `flags` is an initial `struct mg_connection::flags` bitmask to set,
     * see `MG_F_*` flags definitions.
     */
    struct mg_add_sock_opts {
       void *user_data;           /* Initial value for connection's user_data */
       unsigned int flags;        /* Initial connection flags */
       const char **error_string; /* Placeholder for the error string */
    };
    
    /*
     * Create a connection, associate it with the given socket and event handler,
     * and add it to the manager.
     *
     * For more options see the `mg_add_sock_opt` variant.
     */
    struct mg_connection *mg_add_sock(struct mg_mgr *, sock_t, mg_event_handler_t);
    
    /*
     * Create a connection, associate it with the given socket and event handler,
     * and add to the manager.
     *
     * See the `mg_add_sock_opts` structure for a description of the options.
     */
    struct mg_connection *mg_add_sock_opt(struct mg_mgr *, sock_t,
                                          mg_event_handler_t,
                                          struct mg_add_sock_opts);
    
    /*
     * Optional parameters to `mg_bind_opt()`.
     *
     * `flags` is an initial `struct mg_connection::flags` bitmask to set,
     * see `MG_F_*` flags definitions.
     */
    struct mg_bind_opts {
       void *user_data;           /* Initial value for connection's user_data */
       unsigned int flags;        /* Extra connection flags */
       const char **error_string; /* Placeholder for the error string */
 #ifdef MG_ENABLE_SSL
       /* SSL settings. */
       const char *ssl_cert;    /* Server certificate to present to clients */
       const char *ssl_ca_cert; /* Verify client certificates with this CA bundle */
 #endif
    };
    
    /*
     * Create listening connection.
     *
     * See `mg_bind_opt` for full documentation.
     */
    struct mg_connection *mg_bind(struct mg_mgr *, const char *,
                                  mg_event_handler_t);
    /*
     * Create listening connection.
     *
     * `address` parameter tells which address to bind to. It's format is the same
     * as for the `mg_connect()` call, where `HOST` part is optional. `address`
     * can be just a port number, e.g. `:8000`. To bind to a specific interface,
     * an IP address can be specified, e.g. `1.2.3.4:8000`. By default, a TCP
     * connection is created. To create UDP connection, prepend `udp://` prefix,
     * e.g. `udp://:8000`. To summarize, `address` paramer has following format:
     * `[PROTO://][IP_ADDRESS]:PORT`, where `PROTO` could be `tcp` or `udp`.
     *
     * See the `mg_bind_opts` structure for a description of the optional
     * parameters.
     *
     * Return a new listening connection, or `NULL` on error.
     * NOTE: Connection remains owned by the manager, do not free().
     */
    struct mg_connection *mg_bind_opt(struct mg_mgr *mgr, const char *address,
                                      mg_event_handler_t handler,
                                      struct mg_bind_opts opts);
    
    /* Optional parameters to `mg_connect_opt()` */
    struct mg_connect_opts {
       void *user_data;           /* Initial value for connection's user_data */
       unsigned int flags;        /* Extra connection flags */
       const char **error_string; /* Placeholder for the error string */
 #ifdef MG_ENABLE_SSL
       /* SSL settings. */
       const char *ssl_cert;    /* Client certificate to present to the server */
       const char *ssl_ca_cert; /* Verify server certificate using this CA bundle */
       
       /*
        * Server name verification. If ssl_ca_cert is set and the certificate has
        * passed verification, its subject will be verified against this string.
        * By default (if ssl_server_name is NULL) hostname part of the address will
        * be used. Wildcard matching is supported. A special value of "*" disables
        * name verification.
        */
       const char *ssl_server_name;
 #endif
    };
    
    /*
     * Connect to a remote host.
     *
     * See `mg_connect_opt()` for full documentation.
     */
    struct mg_connection *mg_connect(struct mg_mgr *mgr, const char *address,
                                     mg_event_handler_t handler);
    
    /*
     * Connect to a remote host.
     *
     * `address` format is `[PROTO://]HOST:PORT`. `PROTO` could be `tcp` or `udp`.
     * `HOST` could be an IP address,
     * IPv6 address (if Mongoose is compiled with `-DMG_ENABLE_IPV6`), or a host
     * name. If `HOST` is a name, Mongoose will resolve it asynchronously. Examples
     * of valid addresses: `google.com:80`, `udp://1.2.3.4:53`, `10.0.0.1:443`,
     * `[::1]:80`
     *
     * See the `mg_connect_opts` structure for a description of the optional
     * parameters.
     *
     * Returns a new outbound connection, or `NULL` on error.
     *
     * NOTE: Connection remains owned by the manager, do not free().
     *
     * NOTE: To enable IPv6 addresses, `-DMG_ENABLE_IPV6` should be specified
     * in the compilation flags.
     *
     * NOTE: New connection will receive `MG_EV_CONNECT` as it's first event
     * which will report connect success status.
     * If asynchronous resolution fail, or `connect()` syscall fail for whatever
     * reason (e.g. with `ECONNREFUSED` or `ENETUNREACH`), then `MG_EV_CONNECT`
     * event report failure. Code example below:
     *
     * ```c
     * static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
     *   int connect_status;
     *
     *   switch (ev) {
     *     case MG_EV_CONNECT:
     *       connect_status = * (int *) ev_data;
     *       if (connect_status == 0) {
     *         // Success
     *       } else  {
     *         // Error
     *         printf("connect() error: %s\n", strerror(connect_status));
     *       }
     *       break;
     *     ...
     *   }
     * }
     *
     *   ...
     *   mg_connect(mgr, "my_site.com:80", ev_handler);
     * ```
     */
    struct mg_connection *mg_connect_opt(struct mg_mgr *mgr, const char *address,
                                         mg_event_handler_t handler,
                                         struct mg_connect_opts opts);
    
    /*
     * Enable SSL for a given connection.
     * `cert` is a server certificate file name for a listening connection,
     * or a client certificate file name for an outgoing connection.
     * Certificate files must be in PEM format. Server certificate file
     * must contain a certificate, concatenated with a private key, optionally
     * concatenated with parameters.
     * `ca_cert` is a CA certificate, or NULL if peer verification is not
     * required.
     * Return: NULL on success, or error message on error.
     */
    const char *mg_set_ssl(struct mg_connection *nc, const char *cert,
                           const char *ca_cert);
    
    /*
     * Send data to the connection.
     *
     * Note that sending functions do not actually push data to the socket.
     * They just append data to the output buffer. MG_EV_SEND will be delivered when
     * the data has actually been pushed out.
     */
    void mg_send(struct mg_connection *, const void *buf, int len);
    
    /* Enables format string warnings for mg_printf */
 #if defined(__GNUC__)
    __attribute__((format(printf, 2, 3)))
 #endif
    /* don't separate from mg_printf declaration */
    
    /*
     * Send `printf`-style formatted data to the connection.
     *
     * See `mg_send` for more details on send semantics.
     */
    int mg_printf(struct mg_connection *, const char *fmt, ...);
    
    /* Same as `mg_printf()`, but takes `va_list ap` as an argument. */
    int mg_vprintf(struct mg_connection *, const char *fmt, va_list ap);
    
    /*
     * Create a socket pair.
     * `sock_type` can be either `SOCK_STREAM` or `SOCK_DGRAM`.
     * Return 0 on failure, 1 on success.
     */
    int mg_socketpair(sock_t[2], int sock_type);
    
    /*
     * Convert domain name into IP address.
     *
     * This is a utility function. If compilation flags have
     * `-DMG_ENABLE_GETADDRINFO`, then `getaddrinfo()` call is used for name
     * resolution. Otherwise, `gethostbyname()` is used.
     *
     * CAUTION: this function can block.
     * Return 1 on success, 0 on failure.
     */
 #ifndef MG_DISABLE_SYNC_RESOLVER
    int mg_resolve(const char *domain_name, char *ip_addr_buf, size_t buf_len);
 #endif
    
    /*
     * Verify given IP address against the ACL.
     *
     * `remote_ip` - an IPv4 address to check, in host byte order
     * `acl` - a comma separated list of IP subnets: `x.x.x.x/x` or `x.x.x.x`.
     * Each subnet is
     * prepended by either a - or a + sign. A plus sign means allow, where a
     * minus sign means deny. If a subnet mask is omitted, such as `-1.2.3.4`,
     * this means to deny only that single IP address.
     * Subnet masks may vary from 0 to 32, inclusive. The default setting
     * is to allow all accesses. On each request the full list is traversed,
     * and the last match wins. Example:
     *
     * `-0.0.0.0/0,+192.168/16` - deny all acccesses, only allow 192.168/16 subnet
     *
     * To learn more about subnet masks, see the
     * link:https://en.wikipedia.org/wiki/Subnetwork[Wikipedia page on Subnetwork]
     *
     * Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
     */
    int mg_check_ip_acl(const char *acl, uint32_t remote_ip);
    
    /*
     * Enable multi-threaded handling for the given listening connection `nc`.
     * For each accepted connection, Mongoose will create a separate thread
     * and run event handler in that thread. Thus, if an event hanler is doing
     * a blocking call or some long computation, that will not slow down
     * other connections.
     */
    void mg_enable_multithreading(struct mg_connection *nc);
    
 #ifdef MG_ENABLE_JAVASCRIPT
    /*
     * Enable server-side JavaScript scripting.
     * Requires `-DMG_ENABLE_JAVASCRIPT` compilation flag, and V7 engine sources.
     * v7 instance must not be destroyed during manager's lifetime.
     * Return V7 error.
     */
    enum v7_err mg_enable_javascript(struct mg_mgr *m, struct v7 *v7,
                                     const char *init_js_file_name);
 #endif
    
    /*
     * Schedule MG_EV_TIMER event to be delivered at `timestamp` time.
     * `timestamp` is a UNIX time (a number of seconds since Epoch). It is
     * `double` instead of `time_t` to allow for sub-second precision.
     * Return the old timer value.
     *
     * Example: set connect timeout to 1.5 seconds:
     *
     * ```
     *  c = mg_connect(&mgr, "cesanta.com", ev_handler);
     *  mg_set_timer(c, mg_time() + 1.5);
     *  ...
     *
     *  void ev_handler(struct mg_connection *c, int ev, void *ev_data) {
     *  switch (ev) {
     *    case MG_EV_CONNECT:
     *      mg_set_timer(c, 0);  // Clear connect timer
     *      break;
     *    case MG_EV_TIMER:
     *      log("Connect timeout");
     *      c->flags |= MG_F_CLOSE_IMMEDIATELY;
     *      break;
     * ```
     */
    double mg_set_timer(struct mg_connection *c, double timestamp);
    
    /*
     * A sub-second precision version of time().
     */
    double mg_time();
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_MONGOOSE_SRC_NET_H_ */
 /*
  * Copyright (c) 2014-2016 Cesanta Software Limited
  * All rights reserved
  */
 
 #ifndef CS_MONGOOSE_SRC_NET_IF_H_
 #define CS_MONGOOSE_SRC_NET_IF_H_
 
 /*
  * Internal async networking core interface.
  * Consists of calls made by the core, which should not block,
  * and callbacks back into the core ("..._cb").
  * Callbacks may (will) cause methods to be invoked from within,
  * but methods are not allowed to invoke callbacks inline.
  *
  * Implementation must ensure that only one callback is invoked at any time.
  */
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /* Request that a TCP connection is made to the specified address. */
    void mg_if_connect_tcp(struct mg_connection *nc,
                           const union socket_address *sa);
    /* Open a UDP socket. Doesn't actually connect anything. */
    void mg_if_connect_udp(struct mg_connection *nc);
    /* Callback invoked by connect methods. err = 0 -> ok, != 0 -> error. */
    void mg_if_connect_cb(struct mg_connection *nc, int err);
    
    /* Set up a listening TCP socket on a given address. rv = 0 -> ok. */
    int mg_if_listen_tcp(struct mg_connection *nc, union socket_address *sa);
    
    /*
     * Deliver a new TCP connection. Returns NULL in case on error (unable to
     * create connection, in which case interface state should be discarded.
     * This is phase 1 of the two-phase process - MG_EV_ACCEPT will be delivered
     * when mg_if_accept_tcp_cb is invoked.
     */
    struct mg_connection *mg_if_accept_new_conn(struct mg_connection *lc);
    void mg_if_accept_tcp_cb(struct mg_connection *nc, union socket_address *sa,
                             size_t sa_len);
    
    /* Request that a "listening" UDP socket be created. */
    int mg_if_listen_udp(struct mg_connection *nc, union socket_address *sa);
    
    /* Send functions for TCP and UDP. Sent data is copied before return. */
    void mg_if_tcp_send(struct mg_connection *nc, const void *buf, size_t len);
    void mg_if_udp_send(struct mg_connection *nc, const void *buf, size_t len);
    /* Callback that reports that data has been put on the wire. */
    void mg_if_sent_cb(struct mg_connection *nc, int num_sent);
    
    /*
     * Receive callback.
     * buf must be heap-allocated and ownership is transferred to the core.
     * Core will acknowledge consumption by calling mg_if_recved.
     */
    void mg_if_recv_tcp_cb(struct mg_connection *nc, void *buf, int len);
    void mg_if_recv_udp_cb(struct mg_connection *nc, void *buf, int len,
                           union socket_address *sa, size_t sa_len);
    void mg_if_recved(struct mg_connection *nc, size_t len);
    
    /* Deliver a POLL event to the connection. */
    void mg_if_poll(struct mg_connection *nc, time_t now);
    
    /* Deliver a TIMER event to the connection. */
    void mg_if_timer(struct mg_connection *c, double now);
    
    /* Perform interface-related connection initialization. Return 1 on success. */
    int mg_if_create_conn(struct mg_connection *nc);
    
    /* Perform interface-related cleanup on connection before destruction. */
    void mg_if_destroy_conn(struct mg_connection *nc);
    
    void mg_close_conn(struct mg_connection *nc);
    
    /* Put connection's address into *sa, local (remote = 0) or remote. */
    void mg_if_get_conn_addr(struct mg_connection *nc, int remote,
                             union socket_address *sa);
    
    /* Associate a socket to a connection. */
    void mg_sock_set(struct mg_connection *nc, sock_t sock);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_MONGOOSE_SRC_NET_IF_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === URI
  */
 
 #ifndef CS_MONGOOSE_SRC_URI_H_
 #define CS_MONGOOSE_SRC_URI_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /*
     * Parses an URI and fills string chunks with locations of the respective
     * uri components within the input uri string. NULL pointers will be
     * ignored.
     *
     * General syntax:
     *
     *     [scheme://[user_info@]]host[:port][/path][?query][#fragment]
     *
     * Example:
     *
     *     foo.com:80
     *     tcp://foo.com:1234
     *     http://foo.com:80/bar?baz=1
     *     https://user:pw@foo.com:443/blah
     *
     * `path` will include the leading slash. `query` won't include the leading `?`.
     * `host` can contain embedded colons if surrounded by square brackets in order
     * to support IPv6 literal addresses.
     *
     *
     * Returns 0 on success, -1 on error.
     */
    int mg_parse_uri(struct mg_str uri, struct mg_str *scheme,
                     struct mg_str *user_info, struct mg_str *host,
                     unsigned int *port, struct mg_str *path, struct mg_str *query,
                     struct mg_str *fragment);
    
    int mg_normalize_uri_path(const struct mg_str *in, struct mg_str *out);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_URI_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === Utilities
  */
 
 #ifndef CS_MONGOOSE_SRC_UTIL_H_
 #define CS_MONGOOSE_SRC_UTIL_H_
 
 #include <stdio.h>
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #ifndef MAX_PATH_SIZE
 #define MAX_PATH_SIZE 500
 #endif
    
    /*
     * Fetch substring from input string `s`, `end` into `v`.
     * Skips initial delimiter characters. Records first non-delimiter character
     * as the beginning of substring `v`. Then scans the rest of the string
     * until a delimiter character or end-of-string is found.
     * `delimiters` is a 0-terminated string containing delimiter characters.
     * Either one of `delimiters` or `end_string` terminates the search.
     * Return an `s` pointer, advanced forward where parsing stopped.
     */
    const char *mg_skip(const char *s, const char *end_string,
                        const char *delimiters, struct mg_str *v);
    
    /*
     * Cross-platform version of `strncasecmp()`.
     */
    int mg_ncasecmp(const char *s1, const char *s2, size_t len);
    
    /*
     * Cross-platform version of `strcasecmp()`.
     */
    int mg_casecmp(const char *s1, const char *s2);
    
    /*
     * Cross-platform version of `strcmp()` where where first string is
     * specified by `struct mg_str`.
     */
    int mg_vcmp(const struct mg_str *str2, const char *str1);
    
    /*
     * Cross-platform version of `strncasecmp()` where first string is
     * specified by `struct mg_str`.
     */
    int mg_vcasecmp(const struct mg_str *str2, const char *str1);
    
    /*
     * Decode base64-encoded string `s`, `len` into the destination `dst`.
     * Destination has to have enough space to hold decoded buffer.
     * Decoding stops either when all string has been decoded, or invalid
     * character appeared.
     * Destination is '\0'-terminated.
     * Return number of decoded characters. On success, that should be equal to
     * `len`. On error (invalid character) the return value is smaller then `len`.
     */
    int mg_base64_decode(const unsigned char *s, int len, char *dst);
    
    /*
     * Base64-encode chunk of memory `src`, `src_len` into the destination `dst`.
     * Destination has to have enough space to hold encoded buffer.
     * Destination is '\0'-terminated.
     */
    void mg_base64_encode(const unsigned char *src, int src_len, char *dst);
    
 #ifndef MG_DISABLE_FILESYSTEM
    /*
     * Perform a 64-bit `stat()` call against given file.
     *
     * `path` should be UTF8 encoded.
     *
     * Return value is the same as for `stat()` syscall.
     */
    int mg_stat(const char *path, cs_stat_t *st);
    
    /*
     * Open the given file and return a file stream.
     *
     * `path` and `mode` should be UTF8 encoded.
     *
     * Return value is the same as for the `fopen()` call.
     */
    FILE *mg_fopen(const char *path, const char *mode);
    
    /*
     * Open the given file and return a file stream.
     *
     * `path` should be UTF8 encoded.
     *
     * Return value is the same as for the `open()` syscall.
     */
    int mg_open(const char *path, int flag, int mode);
 #endif /* MG_DISABLE_FILESYSTEM */
    
 #if defined(_WIN32) && !defined(MG_ENABLE_THREADS)
 #define MG_ENABLE_THREADS
 #endif
    
 #ifdef MG_ENABLE_THREADS
    /*
     * Start a new detached thread.
     * Arguments and semantic is the same as pthead's `pthread_create()`.
     * `thread_func` is a thread function, `thread_func_param` is a parameter
     * that is passed to the thread function.
     */
    void *mg_start_thread(void *(*thread_func)(void *), void *thread_func_param);
 #endif
    
    void mg_set_close_on_exec(sock_t);
    
 #define MG_SOCK_STRINGIFY_IP 1
 #define MG_SOCK_STRINGIFY_PORT 2
 #define MG_SOCK_STRINGIFY_REMOTE 4
    /*
     * Convert connection's local or remote address into string.
     *
     * The `flags` parameter is a bit mask that controls the behavior,
     * see `MG_SOCK_STRINGIFY_*` definitions.
     *
     * - MG_SOCK_STRINGIFY_IP - print IP address
     * - MG_SOCK_STRINGIFY_PORT - print port number
     * - MG_SOCK_STRINGIFY_REMOTE - print remote peer's IP/port, not local address
     *
     * If both port number and IP address are printed, they are separated by `:`.
     * If compiled with `-DMG_ENABLE_IPV6`, IPv6 addresses are supported.
     */
    void mg_conn_addr_to_str(struct mg_connection *nc, char *buf, size_t len,
                             int flags);
 #ifndef MG_DISABLE_SOCKET_IF /* Legacy interface. */
    void mg_sock_to_str(sock_t sock, char *buf, size_t len, int flags);
 #endif
    
    /*
     * Convert socket's address into string.
     *
     * `flags` is MG_SOCK_STRINGIFY_IP and/or MG_SOCK_STRINGIFY_PORT.
     */
    void mg_sock_addr_to_str(const union socket_address *sa, char *buf, size_t len,
                             int flags);
    
    /*
     * Generates human-readable hexdump of memory chunk.
     *
     * Takes a memory buffer `buf` of length `len` and creates a hex dump of that
     * buffer in `dst`. Generated output is a-la hexdump(1).
     * Return length of generated string, excluding terminating `\0`. If returned
     * length is bigger than `dst_len`, overflow bytes are discarded.
     */
    int mg_hexdump(const void *buf, int len, char *dst, int dst_len);
    
    /*
     * Generates human-readable hexdump of the data sent or received by connection.
     * `path` is a file name where hexdump should be written. `num_bytes` is
     * a number of bytes sent/received. `ev` is one of the `MG_*` events sent to
     * an event handler. This function is supposed to be called from the
     * event handler.
     */
    void mg_hexdump_connection(struct mg_connection *nc, const char *path,
                               const void *buf, int num_bytes, int ev);
    /*
     * Print message to buffer. If buffer is large enough to hold the message,
     * return buffer. If buffer is to small, allocate large enough buffer on heap,
     * and return allocated buffer.
     * This is a supposed use case:
     *
     *    char buf[5], *p = buf;
     *    p = mg_avprintf(&p, sizeof(buf), "%s", "hi there");
     *    use_p_somehow(p);
     *    if (p != buf) {
     *      free(p);
     *    }
     *
     * The purpose of this is to avoid malloc-ing if generated strings are small.
     */
    int mg_avprintf(char **buf, size_t size, const char *fmt, va_list ap);
    
    /*
     * Return true if target platform is big endian.
     */
    int mg_is_big_endian(void);
    
    /*
     * A helper function for traversing a comma separated list of values.
     * It returns a list pointer shifted to the next value, or NULL if the end
     * of the list found.
     * Value is stored in val vector. If value has form "x=y", then eq_val
     * vector is initialized to point to the "y" part, and val vector length
     * is adjusted to point only to "x".
     * If list is just a comma separated list of entries, like "aa,bb,cc" then
     * `eq_val` will contain zero-length string.
     *
     * The purpose of this function is to parse comma separated string without
     * any copying/memory allocation.
     */
    const char *mg_next_comma_list_entry(const char *list, struct mg_str *val,
                                         struct mg_str *eq_val);
    
    /*
     * Match 0-terminated string (mg_match_prefix) or string with given length
     * mg_match_prefix_n against a glob pattern.
     * Match is case-insensitive. Return number of bytes matched, or -1 if no match.
     */
    int mg_match_prefix(const char *pattern, int pattern_len, const char *str);
    int mg_match_prefix_n(const struct mg_str pattern, const struct mg_str str);
    
    /*
     * A helper function for creating mg_str struct from plain C string.
     * `NULL` is allowed and becomes `{NULL, 0}`.
     */
    struct mg_str mg_mk_str(const char *s);
    
    /* Macro for initializing mg_str. */
 #define MG_MK_STR(str_literal) \
 { str_literal, sizeof(str_literal) - 1 }
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_UTIL_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === HTTP + Websocket
  */
 
 #ifndef CS_MONGOOSE_SRC_HTTP_H_
 #define CS_MONGOOSE_SRC_HTTP_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #ifndef MG_MAX_HTTP_HEADERS
 #define MG_MAX_HTTP_HEADERS 20
 #endif
    
 #ifndef MG_MAX_HTTP_REQUEST_SIZE
 #define MG_MAX_HTTP_REQUEST_SIZE 1024
 #endif
    
 #ifndef MG_MAX_PATH
 #ifdef PATH_MAX
 #define MG_MAX_PATH PATH_MAX
 #else
 #define MG_MAX_PATH 256
 #endif
 #endif
    
 #ifndef MG_MAX_HTTP_SEND_MBUF
 #define MG_MAX_HTTP_SEND_MBUF 1024
 #endif
    
 #ifndef MG_WEBSOCKET_PING_INTERVAL_SECONDS
 #define MG_WEBSOCKET_PING_INTERVAL_SECONDS 5
 #endif
    
 #ifndef MG_CGI_ENVIRONMENT_SIZE
 #define MG_CGI_ENVIRONMENT_SIZE 8192
 #endif
    
 #ifndef MG_MAX_CGI_ENVIR_VARS
 #define MG_MAX_CGI_ENVIR_VARS 64
 #endif
    
 #ifndef MG_ENV_EXPORT_TO_CGI
 #define MG_ENV_EXPORT_TO_CGI "MONGOOSE_CGI"
 #endif
    
    /* HTTP message */
    struct http_message {
       struct mg_str message; /* Whole message: request line + headers + body */
       
       /* HTTP Request line (or HTTP response line) */
       struct mg_str method; /* "GET" */
       struct mg_str uri;    /* "/my_file.html" */
       struct mg_str proto;  /* "HTTP/1.1" -- for both request and response */
       
       /* For responses, code and response status message are set */
       int resp_code;
       struct mg_str resp_status_msg;
       
       /*
        * Query-string part of the URI. For example, for HTTP request
        *    GET /foo/bar?param1=val1&param2=val2
        *    |    uri    |     query_string     |
        *
        * Note that question mark character doesn't belong neither to the uri,
        * nor to the query_string
        */
       struct mg_str query_string;
       
       /* Headers */
       struct mg_str header_names[MG_MAX_HTTP_HEADERS];
       struct mg_str header_values[MG_MAX_HTTP_HEADERS];
       
       /* Message body */
       struct mg_str body; /* Zero-length for requests with no body */
    };
    
    /* WebSocket message */
    struct websocket_message {
       unsigned char *data;
       size_t size;
       unsigned char flags;
    };
    
    /* HTTP multipart part */
    struct mg_http_multipart_part {
       const char *file_name;
       const char *var_name;
       struct mg_str data;
       int status; /* <0 on error */
       void *user_data;
    };
    
    /* HTTP and websocket events. void *ev_data is described in a comment. */
 #define MG_EV_HTTP_REQUEST 100 /* struct http_message * */
 #define MG_EV_HTTP_REPLY 101   /* struct http_message * */
 #define MG_EV_HTTP_CHUNK 102   /* struct http_message * */
 #define MG_EV_SSI_CALL 105     /* char * */
    
 #define MG_EV_WEBSOCKET_HANDSHAKE_REQUEST 111 /* NULL */
 #define MG_EV_WEBSOCKET_HANDSHAKE_DONE 112    /* NULL */
 #define MG_EV_WEBSOCKET_FRAME 113             /* struct websocket_message * */
 #define MG_EV_WEBSOCKET_CONTROL_FRAME 114     /* struct websocket_message * */
    
 #ifdef MG_ENABLE_HTTP_STREAMING_MULTIPART
 #define MG_EV_HTTP_MULTIPART_REQUEST 121 /* struct http_message */
 #define MG_EV_HTTP_PART_BEGIN 122        /* struct mg_http_multipart_part */
 #define MG_EV_HTTP_PART_DATA 123         /* struct mg_http_multipart_part */
 #define MG_EV_HTTP_PART_END 124          /* struct mg_http_multipart_part */
 #endif
    
    /*
     * Attach built-in HTTP event handler to the given connection.
     * User-defined event handler will receive following extra events:
     *
     * - MG_EV_HTTP_REQUEST: HTTP request has arrived. Parsed HTTP request
     *  is passed as
     *   `struct http_message` through the handler's `void *ev_data` pointer.
     * - MG_EV_HTTP_MULTIPART_REQUEST: A multipart POST request has received.
     *   This event is sent before body is parsed. After this user
     *   should expect a sequence of MG_EV_HTTP_PART_BEGIN/DATA/END requests.
     *   This is also the last time when headers and other request fields are
     *   accessible.
     * - MG_EV_HTTP_REPLY: HTTP reply has arrived. Parsed HTTP reply is passed as
     *   `struct http_message` through the handler's `void *ev_data` pointer.
     * - MG_EV_HTTP_CHUNK: HTTP chunked-encoding chunk has arrived.
     *   Parsed HTTP reply is passed as `struct http_message` through the
     *   handler's `void *ev_data` pointer. `http_message::body` would contain
     *   incomplete, reassembled HTTP body.
     *   It will grow with every new chunk arrived, and
     *   potentially can consume a lot of memory. An event handler may process
     *   the body as chunks are coming, and signal Mongoose to delete processed
     *   body by setting `MG_F_DELETE_CHUNK` in `mg_connection::flags`. When
     *   the last zero chunk is received,
     *   Mongoose sends `MG_EV_HTTP_REPLY` event with
     *   full reassembled body (if handler did not signal to delete chunks) or
     *   with empty body (if handler did signal to delete chunks).
     * - MG_EV_WEBSOCKET_HANDSHAKE_REQUEST: server has received websocket handshake
     *   request. `ev_data` contains parsed HTTP request.
     * - MG_EV_WEBSOCKET_HANDSHAKE_DONE: server has completed Websocket handshake.
     *   `ev_data` is `NULL`.
     * - MG_EV_WEBSOCKET_FRAME: new websocket frame has arrived. `ev_data` is
     *   `struct websocket_message *`
     * - MG_EV_HTTP_PART_BEGIN: new part of multipart message is started,
     *   extra parameters are passed in mg_http_multipart_part
     * - MG_EV_HTTP_PART_DATA: new portion of data from multiparted message
     *   no additional headers are available, only data and data size
     * - MG_EV_HTTP_PART_END: final boundary received, analogue to maybe used to
     *   find the end of packet
     *   Note: Mongoose should be compiled with MG_ENABLE_HTTP_STREAMING_MULTIPART
     *   to enable MG_EV_HTTP_MULTIPART_REQUEST, MG_EV_HTTP_REQUEST_END,
     *   MG_EV_HTTP_REQUEST_CANCEL, MG_EV_HTTP_PART_BEGIN, MG_EV_HTTP_PART_DATA,
     *   MG_EV_HTTP_PART_END constants
     */
    void mg_set_protocol_http_websocket(struct mg_connection *nc);
    
    /*
     * Send websocket handshake to the server.
     *
     * `nc` must be a valid connection, connected to a server. `uri` is an URI
     * to fetch, extra_headers` is extra HTTP headers to send or `NULL`.
     *
     * This function is intended to be used by websocket client.
     *
     * Note that the Host header is mandatory in HTTP/1.1 and must be
     * included in `extra_headers`. `mg_send_websocket_handshake2` offers
     * a better API for that.
     *
     * Deprecated in favour of `mg_send_websocket_handshake2`
     */
    void mg_send_websocket_handshake(struct mg_connection *nc, const char *uri,
                                     const char *extra_headers);
    
    /*
     * Send websocket handshake to the server.
     *
     * `nc` must be a valid connection, connected to a server. `uri` is an URI
     * to fetch, `host` goes into the `Host` header, `protocol` goes into the
     * `Sec-WebSocket-Proto` header (NULL to omit), extra_headers` is extra HTTP
     * headers to send or `NULL`.
     *
     * This function is intended to be used by websocket client.
     */
    void mg_send_websocket_handshake2(struct mg_connection *nc, const char *path,
                                      const char *host, const char *protocol,
                                      const char *extra_headers);
    
    /*
     * Helper function that creates an outbound WebSocket connection.
     *
     * `url` is a URL to connect to. It must be properly URL-encoded, e.g. have
     * no spaces, etc. By default, `mg_connect_ws()` sends Connection and
     * Host headers. `extra_headers` is an extra HTTP headers to send, e.g.
     * `"User-Agent: my-app\r\n"`.
     * If `protocol` is not NULL, then a `Sec-WebSocket-Protocol` header is sent.
     *
     * Examples:
     *
     * ```c
     *   nc1 = mg_connect_ws(mgr, ev_handler_1, "ws://echo.websocket.org", NULL,
     *                       NULL);
     *   nc2 = mg_connect_ws(mgr, ev_handler_1, "wss://echo.websocket.org", NULL,
     *                       NULL);
     *   nc3 = mg_connect_ws(mgr, ev_handler_1, "ws://api.cesanta.com",
     *                       "clubby.cesanta.com", NULL);
     * ```
     */
    struct mg_connection *mg_connect_ws(struct mg_mgr *mgr,
                                        mg_event_handler_t event_handler,
                                        const char *url, const char *protocol,
                                        const char *extra_headers);
    
    /*
     * Helper function that creates an outbound WebSocket connection
     *
     * Mostly identical to mg_connect_ws, but allows to provide extra parameters
     * (for example, SSL parameters
     */
    struct mg_connection *mg_connect_ws_opt(struct mg_mgr *mgr,
                                            mg_event_handler_t ev_handler,
                                            struct mg_connect_opts opts,
                                            const char *url, const char *protocol,
                                            const char *extra_headers);
    
    /*
     * Send websocket frame to the remote end.
     *
     * `op_and_flags` specifies frame's type, one of:
     *
     * - WEBSOCKET_OP_CONTINUE
     * - WEBSOCKET_OP_TEXT
     * - WEBSOCKET_OP_BINARY
     * - WEBSOCKET_OP_CLOSE
     * - WEBSOCKET_OP_PING
     * - WEBSOCKET_OP_PONG
     *
     * Orred with one of the flags:
     *
     * - WEBSOCKET_DONT_FIN: Don't set the FIN flag on the frame to be sent.
     *
     * `data` and `data_len` contain frame data.
     */
    void mg_send_websocket_frame(struct mg_connection *nc, int op_and_flags,
                                 const void *data, size_t data_len);
    
    /*
     * Send multiple websocket frames.
     *
     * Like `mg_send_websocket_frame()`, but composes a frame from multiple buffers.
     */
    void mg_send_websocket_framev(struct mg_connection *nc, int op_and_flags,
                                  const struct mg_str *strings, int num_strings);
    
    /*
     * Send websocket frame to the remote end.
     *
     * Like `mg_send_websocket_frame()`, but allows to create formatted message
     * with `printf()`-like semantics.
     */
    void mg_printf_websocket_frame(struct mg_connection *nc, int op_and_flags,
                                   const char *fmt, ...);
    
    /*
     * Send buffer `buf` of size `len` to the client using chunked HTTP encoding.
     * This function first sends buffer size as hex number + newline, then
     * buffer itself, then newline. For example,
     *   `mg_send_http_chunk(nc, "foo", 3)` whill append `3\r\nfoo\r\n` string to
     * the `nc->send_mbuf` output IO buffer.
     *
     * NOTE: HTTP header "Transfer-Encoding: chunked" should be sent prior to
     * using this function.
     *
     * NOTE: do not forget to send empty chunk at the end of the response,
     * to tell the client that everything was sent. Example:
     *
     * ```
     *   mg_printf_http_chunk(nc, "%s", "my response!");
     *   mg_send_http_chunk(nc, "", 0); // Tell the client we're finished
     * ```
     */
    void mg_send_http_chunk(struct mg_connection *nc, const char *buf, size_t len);
    
    /*
     * Send printf-formatted HTTP chunk.
     * Functionality is similar to `mg_send_http_chunk()`.
     */
    void mg_printf_http_chunk(struct mg_connection *nc, const char *fmt, ...);
    
    /*
     * Send response status line.
     * If `extra_headers` is not NULL, then `extra_headers` are also sent
     * after the reponse line. `extra_headers` must NOT end end with new line.
     * Example:
     *
     *      mg_send_response_line(nc, 200, "Access-Control-Allow-Origin: *");
     *
     * Will result in:
     *
     *      HTTP/1.1 200 OK\r\n
     *      Access-Control-Allow-Origin: *\r\n
     */
    void mg_send_response_line(struct mg_connection *c, int status_code,
                               const char *extra_headers);
    
    /*
     * Send response line and headers.
     * This function sends response line with the `status_code`, and automatically
     * sends one header: either "Content-Length", or "Transfer-Encoding".
     * If `content_length` is negative, then "Transfer-Encoding: chunked" header
     * is sent, otherwise, "Content-Length" header is sent.
     *
     * NOTE: If `Transfer-Encoding` is `chunked`, then message body must be sent
     * using `mg_send_http_chunk()` or `mg_printf_http_chunk()` functions.
     * Otherwise, `mg_send()` or `mg_printf()` must be used.
     * Extra headers could be set through `extra_headers` - and note `extra_headers`
     * must NOT be terminated by a new line.
     */
    void mg_send_head(struct mg_connection *n, int status_code,
                      int64_t content_length, const char *extra_headers);
    
    /*
     * Send printf-formatted HTTP chunk, escaping HTML tags.
     */
    void mg_printf_html_escape(struct mg_connection *nc, const char *fmt, ...);
    
    /* Websocket opcodes, from http://tools.ietf.org/html/rfc6455 */
 #define WEBSOCKET_OP_CONTINUE 0
 #define WEBSOCKET_OP_TEXT 1
 #define WEBSOCKET_OP_BINARY 2
 #define WEBSOCKET_OP_CLOSE 8
 #define WEBSOCKET_OP_PING 9
 #define WEBSOCKET_OP_PONG 10
    
    /*
     * If set causes the FIN flag to not be set on outbound
     * frames. This enables sending multiple fragments of a single
     * logical message.
     *
     * The WebSocket protocol mandates that if the FIN flag of a data
     * frame is not set, the next frame must be a WEBSOCKET_OP_CONTINUE.
     * The last frame must have the FIN bit set.
     *
     * Note that mongoose will automatically defragment incoming messages,
     * so this flag is used only on outbound messages.
     */
 #define WEBSOCKET_DONT_FIN 0x100
    
    /*
     * Parse a HTTP message.
     *
     * `is_req` should be set to 1 if parsing request, 0 if reply.
     *
     * Return number of bytes parsed. If HTTP message is
     * incomplete, `0` is returned. On parse error, negative number is returned.
     */
    int mg_parse_http(const char *s, int n, struct http_message *hm, int is_req);
    
    /*
     * Search and return header `name` in parsed HTTP message `hm`.
     * If header is not found, NULL is returned. Example:
     *
     *     struct mg_str *host_hdr = mg_get_http_header(hm, "Host");
     */
    struct mg_str *mg_get_http_header(struct http_message *hm, const char *name);
    
    /*
     * Parse HTTP header `hdr`. Find variable `var_name` and store it's value
     * in the buffer `buf`, `buf_size`. Return 0 if variable not found, non-zero
     * otherwise.
     *
     * This function is supposed to parse
     * cookies, authentication headers, etcetera. Example (error handling omitted):
     *
     *     char user[20];
     *     struct mg_str *hdr = mg_get_http_header(hm, "Authorization");
     *     mg_http_parse_header(hdr, "username", user, sizeof(user));
     *
     * Return length of the variable's value. If buffer is not large enough,
     * or variable not found, 0 is returned.
     */
    int mg_http_parse_header(struct mg_str *hdr, const char *var_name, char *buf,
                             size_t buf_size);
    
    /*
     * Parse buffer `buf`, `buf_len` that contains multipart form data chunks.
     * Store chunk name in a `var_name`, `var_name_len` buffer.
     * If a chunk is an uploaded file, then `file_name`, `file_name_len` is
     * filled with an uploaded file name. `chunk`, `chunk_len`
     * points to the chunk data.
     *
     * Return: number of bytes to skip to the next chunk, or 0 if there are
     *         no more chunks.
     *
     * Usage example:
     *
     * ```c
     *    static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
     *      switch(ev) {
     *        case MG_EV_HTTP_REQUEST: {
     *          struct http_message *hm = (struct http_message *) ev_data;
     *          char var_name[100], file_name[100];
     *          const char *chunk;
     *          size_t chunk_len, n1, n2;
     *
     *          n1 = n2 = 0;
     *          while ((n2 = mg_parse_multipart(hm->body.p + n1,
     *                                          hm->body.len - n1,
     *                                          var_name, sizeof(var_name),
     *                                          file_name, sizeof(file_name),
     *                                          &chunk, &chunk_len)) > 0) {
     *            printf("var: %s, file_name: %s, size: %d, chunk: [%.*s]\n",
     *                   var_name, file_name, (int) chunk_len,
     *                   (int) chunk_len, chunk);
     *            n1 += n2;
     *          }
     *        }
     *        break;
     * ```
     */
    size_t mg_parse_multipart(const char *buf, size_t buf_len, char *var_name,
                              size_t var_name_len, char *file_name,
                              size_t file_name_len, const char **chunk,
                              size_t *chunk_len);
    
    /*
     * Fetch an HTTP form variable.
     *
     * Fetch a variable `name` from a `buf` into a buffer specified by
     * `dst`, `dst_len`. Destination is always zero-terminated. Return length
     * of a fetched variable. If not found, 0 is returned. `buf` must be
     * valid url-encoded buffer. If destination is too small, `-1` is returned.
     */
    int mg_get_http_var(const struct mg_str *buf, const char *name, char *dst,
                        size_t dst_len);
    
    /*
     * Decode URL-encoded string.
     *
     * Source string is specified by (`src`, `src_len`), and destination is
     * (`dst`, `dst_len`). If `is_form_url_encoded` is non-zero, then
     * `+` character is decoded as a blank space character. This function
     * guarantees to `\0`-terminate the destination. If destination is too small,
     * then source string is partially decoded and `-1` is returned. Otherwise,
     * a length of decoded string is returned, not counting final `\0`.
     */
    int mg_url_decode(const char *src, int src_len, char *dst, int dst_len,
                      int is_form_url_encoded);
    
    /* Create Digest authentication header for client request. */
    int mg_http_create_digest_auth_header(char *buf, size_t buf_len,
                                          const char *method, const char *uri,
                                          const char *auth_domain, const char *user,
                                          const char *passwd);
    
    /*
     * Helper function that creates outbound HTTP connection.
     *
     * `url` is a URL to fetch. It must be properly URL-encoded, e.g. have
     * no spaces, etc. By default, `mg_connect_http()` sends Connection and
     * Host headers. `extra_headers` is an extra HTTP headers to send, e.g.
     * `"User-Agent: my-app\r\n"`.
     * If `post_data` is NULL, then GET request is created. Otherwise, POST request
     * is created with the specified POST data. Note that if the data being posted
     * is a form submission, the `Content-Type` header should be set accordingly
     * (see example below).
     *
     * Examples:
     *
     * ```c
     *   nc1 = mg_connect_http(mgr, ev_handler_1, "http://www.google.com", NULL,
     *                         NULL);
     *   nc2 = mg_connect_http(mgr, ev_handler_1, "https://github.com", NULL, NULL);
     *   nc3 = mg_connect_http(
     *       mgr, ev_handler_1, "my_server:8000/form_submit/",
     *       "Content-Type: application/x-www-form-urlencoded\r\n",
     *       "var_1=value_1&var_2=value_2");
     * ```
     */
    struct mg_connection *mg_connect_http(struct mg_mgr *mgr,
                                          mg_event_handler_t event_handler,
                                          const char *url,
                                          const char *extra_headers,
                                          const char *post_data);
    
    /*
     * Helper function that creates outbound HTTP connection.
     *
     * Mostly identical to mg_connect_http, but allows to provide extra parameters
     * (for example, SSL parameters
     */
    struct mg_connection *mg_connect_http_opt(struct mg_mgr *mgr,
                                              mg_event_handler_t ev_handler,
                                              struct mg_connect_opts opts,
                                              const char *url,
                                              const char *extra_headers,
                                              const char *post_data);
    /*
     * This structure defines how `mg_serve_http()` works.
     * Best practice is to set only required settings, and leave the rest as NULL.
     */
    struct mg_serve_http_opts {
       /* Path to web root directory */
       const char *document_root;
       
       /* List of index files. Default is "" */
       const char *index_files;
       
       /*
        * Leave as NULL to disable authentication.
        * To enable directory protection with authentication, set this to ".htpasswd"
        * Then, creating ".htpasswd" file in any directory automatically protects
        * it with digest authentication.
        * Use `mongoose` web server binary, or `htdigest` Apache utility to
        * create/manipulate passwords file.
        * Make sure `auth_domain` is set to a valid domain name.
        */
       const char *per_directory_auth_file;
       
       /* Authorization domain (domain name of this web server) */
       const char *auth_domain;
       
       /*
        * Leave as NULL to disable authentication.
        * Normally, only selected directories in the document root are protected.
        * If absolutely every access to the web server needs to be authenticated,
        * regardless of the URI, set this option to the path to the passwords file.
        * Format of that file is the same as ".htpasswd" file. Make sure that file
        * is located outside document root to prevent people fetching it.
        */
       const char *global_auth_file;
       
       /* Set to "no" to disable directory listing. Enabled by default. */
       const char *enable_directory_listing;
       
       /* SSI files pattern. If not set, "**.shtml$|**.shtm$" is used. */
       const char *ssi_pattern;
       
       /* IP ACL. By default, NULL, meaning all IPs are allowed to connect */
       const char *ip_acl;
       
       /* URL rewrites.
        *
        * Comma-separated list of `uri_pattern=file_or_directory_path` rewrites.
        * When HTTP request is received, Mongoose constructs a file name from the
        * requested URI by combining `document_root` and the URI. However, if the
        * rewrite option is used and `uri_pattern` matches requested URI, then
        * `document_root` is ignored. Instead, `file_or_directory_path` is used,
        * which should be a full path name or a path relative to the web server's
        * current working directory. Note that `uri_pattern`, as all Mongoose
        * patterns, is a prefix pattern.
        *
        * If uri_pattern starts with `@` symbol, then Mongoose compares it with the
        * HOST header of the request. If they are equal, Mongoose sets document root
        * to `file_or_directory_path`, implementing virtual hosts support.
        * Example: `@foo.com=/document/root/for/foo.com`
        *
        * If `uri_pattern` starts with `%` symbol, then Mongoose compares it with
        * the listening port. If they match, then Mongoose issues a 301 redirect.
        * For example, to redirect all HTTP requests to the
        * HTTPS port, do `%80=https://my.site.com`. Note that the request URI is
        * automatically appended to the redirect location.
        */
       const char *url_rewrites;
       
       /* DAV document root. If NULL, DAV requests are going to fail. */
       const char *dav_document_root;
       
       /*
        * DAV passwords file. If NULL, DAV requests are going to fail.
        * If passwords file is set to "-", then DAV auth is disabled.
        */
       const char *dav_auth_file;
       
       /* Glob pattern for the files to hide. */
       const char *hidden_file_pattern;
       
       /* Set to non-NULL to enable CGI, e.g. **.cgi$|**.php$" */
       const char *cgi_file_pattern;
       
       /* If not NULL, ignore CGI script hashbang and use this interpreter */
       const char *cgi_interpreter;
       
       /*
        * Comma-separated list of Content-Type overrides for path suffixes, e.g.
        * ".txt=text/plain; charset=utf-8,.c=text/plain"
        */
       const char *custom_mime_types;
       
       /*
        * Extra HTTP headers to add to each server response.
        * Example: to enable CORS, set this to "Access-Control-Allow-Origin: *".
        */
       const char *extra_headers;
    };
    
    /*
     * Serve given HTTP request according to the `options`.
     *
     * Example code snippet:
     *
     * ```c
     * static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
     *   struct http_message *hm = (struct http_message *) ev_data;
     *   struct mg_serve_http_opts opts = { .document_root = "/var/www" };  // C99
     *
     *   switch (ev) {
     *     case MG_EV_HTTP_REQUEST:
     *       mg_serve_http(nc, hm, opts);
     *       break;
     *     default:
     *       break;
     *   }
     * }
     * ```
     */
    void mg_serve_http(struct mg_connection *nc, struct http_message *hm,
                       struct mg_serve_http_opts opts);
    
    /*
     * Register callback for specified http endpoint
     * Note: if callback is registered it is called instead of
     * callback provided in mg_bind
     *
     * Example code snippet:
     *
     * ```c
     * static void handle_hello1(struct mg_connection *nc, int ev, void *ev_data) {
     *   (void) ev; (void) ev_data;
     *   mg_printf(nc, "HTTP/1.0 200 OK\r\n\r\n[I am Hello1]");
     *  nc->flags |= MG_F_SEND_AND_CLOSE;
     * }
     *
     * static void handle_hello1(struct mg_connection *nc, int ev, void *ev_data) {
     *  (void) ev; (void) ev_data;
     *   mg_printf(nc, "HTTP/1.0 200 OK\r\n\r\n[I am Hello2]");
     *  nc->flags |= MG_F_SEND_AND_CLOSE;
     * }
     *
     * void init() {
     *   nc = mg_bind(&mgr, local_addr, cb1);
     *   mg_register_http_endpoint(nc, "/hello1", handle_hello1);
     *   mg_register_http_endpoint(nc, "/hello1/hello2", handle_hello2);
     * }
     * ```
     */
    void mg_register_http_endpoint(struct mg_connection *nc, const char *uri_path,
                                   mg_event_handler_t handler);
    
 #ifdef MG_ENABLE_HTTP_STREAMING_MULTIPART
    
    /* Callback prototype for `mg_file_upload_handler()`. */
    typedef struct mg_str (*mg_fu_fname_fn)(struct mg_connection *nc,
    struct mg_str fname);
    
    /*
     * File upload handler.
     * This handler can be used to implement file uploads with minimum code.
     * This handler will process MG_EV_HTTP_PART_* events and store file data into
     * a local file.
     * `local_name_fn` will be invoked with whatever name was provided by the client
     * and will expect the name of the local file to open. Return value of NULL will
     * abort file upload (client will get a "403 Forbidden" response). If non-null,
     * the returned string must be heap-allocated and will be freed by the caller.
     * Exception: it is ok to return the same string verbatim.
     *
     * Example:
     *
     * ```c
     * struct mg_str upload_fname(struct mg_connection *nc, struct mg_str fname) {
     *   // Just return the same filename. Do not actually do this except in test!
     *   // fname is user-controlled and needs to be sanitized.
     *   return fname;
     * }
     * void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
     *   switch (ev) {
     *     ...
     *     case MG_EV_HTTP_PART_BEGIN:
     *     case MG_EV_HTTP_PART_DATA:
     *     case MG_EV_HTTP_PART_END:
     *       mg_file_upload_handler(nc, ev, ev_data, upload_fname);
     *       break;
     *   }
     * }
     * ```
     */
    void mg_file_upload_handler(struct mg_connection *nc, int ev, void *ev_data,
                                mg_fu_fname_fn local_name_fn);
 #endif /* MG_ENABLE_HTTP_STREAMING_MULTIPART */
    
    /*
     * Authenticate HTTP request against opened passwords file.
     * Returns 1 if authenticated, 0 otherwise.
     */
    int mg_http_check_digest_auth(struct http_message *hm, const char *auth_domain,
                                  FILE *fp);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_HTTP_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === JSON-RPC
  */
 
 #ifndef CS_MONGOOSE_SRC_JSON_RPC_H_
 #define CS_MONGOOSE_SRC_JSON_RPC_H_
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /* JSON-RPC request */
    struct mg_rpc_request {
       struct json_token *message; /* Whole RPC message */
       struct json_token *id;      /* Message ID */
       struct json_token *method;  /* Method name */
       struct json_token *params;  /* Method params */
    };
    
    /* JSON-RPC response */
    struct mg_rpc_reply {
       struct json_token *message; /* Whole RPC message */
       struct json_token *id;      /* Message ID */
       struct json_token *result;  /* Remote call result */
    };
    
    /* JSON-RPC error */
    struct mg_rpc_error {
       struct json_token *message;       /* Whole RPC message */
       struct json_token *id;            /* Message ID */
       struct json_token *error_code;    /* error.code */
       struct json_token *error_message; /* error.message */
       struct json_token *error_data;    /* error.data, can be NULL */
    };
    
    /*
     * Parse JSON-RPC reply contained in `buf`, `len` into JSON tokens array
     * `toks`, `max_toks`. If buffer contains valid reply, `reply` structure is
     * populated. The result of RPC call is located in `reply.result`. On error,
     * `error` structure is populated. Returns: the result of calling
     * `parse_json(buf, len, toks, max_toks)`:
     *
     * On success, an offset inside `json_string` is returned
     * where parsing has finished. On failure, a negative number is
     * returned, one of:
     *
     * - `#define JSON_STRING_INVALID           -1`
     * - `#define JSON_STRING_INCOMPLETE        -2`
     * - `#define JSON_TOKEN_ARRAY_TOO_SMALL    -3`
     */
    int mg_rpc_parse_reply(const char *buf, int len, struct json_token *toks,
                           int max_toks, struct mg_rpc_reply *,
                           struct mg_rpc_error *);
    
    /*
     * Create JSON-RPC request in a given buffer.
     *
     * Return length of the request, which
     * can be larger then `len` that indicates an overflow.
     * `params_fmt` format string should conform to `json_emit()` API,
     * see https://github.com/cesanta/frozen
     */
    int mg_rpc_create_request(char *buf, int len, const char *method,
                              const char *id, const char *params_fmt, ...);
    
    /*
     * Create JSON-RPC reply in a given buffer.
     *
     * Return length of the reply, which
     * can be larger then `len` that indicates an overflow.
     * `result_fmt` format string should conform to `json_emit()` API,
     * see https://github.com/cesanta/frozen
     */
    int mg_rpc_create_reply(char *buf, int len, const struct mg_rpc_request *req,
                            const char *result_fmt, ...);
    
    /*
     * Create JSON-RPC error reply in a given buffer.
     *
     * Return length of the error, which
     * can be larger then `len` that indicates an overflow.
     * `fmt` format string should conform to `json_emit()` API,
     * see https://github.com/cesanta/frozen
     */
    int mg_rpc_create_error(char *buf, int len, struct mg_rpc_request *req,
                            int code, const char *message, const char *fmt, ...);
    
    /* JSON-RPC standard error codes */
 #define JSON_RPC_PARSE_ERROR (-32700)
 #define JSON_RPC_INVALID_REQUEST_ERROR (-32600)
 #define JSON_RPC_METHOD_NOT_FOUND_ERROR (-32601)
 #define JSON_RPC_INVALID_PARAMS_ERROR (-32602)
 #define JSON_RPC_INTERNAL_ERROR (-32603)
 #define JSON_RPC_SERVER_ERROR (-32000)
    
    /*
     * Create JSON-RPC error in a given buffer.
     *
     * Return length of the error, which
     * can be larger then `len` that indicates an overflow. See
     * JSON_RPC_*_ERROR definitions for standard error values:
     *
     * - `#define JSON_RPC_PARSE_ERROR (-32700)`
     * - `#define JSON_RPC_INVALID_REQUEST_ERROR (-32600)`
     * - `#define JSON_RPC_METHOD_NOT_FOUND_ERROR (-32601)`
     * - `#define JSON_RPC_INVALID_PARAMS_ERROR (-32602)`
     * - `#define JSON_RPC_INTERNAL_ERROR (-32603)`
     * - `#define JSON_RPC_SERVER_ERROR (-32000)`
     */
    int mg_rpc_create_std_error(char *buf, int len, struct mg_rpc_request *req,
                                int code);
    
    typedef int (*mg_rpc_handler_t)(char *buf, int len, struct mg_rpc_request *req);
    
    /*
     * Dispatches a JSON-RPC request.
     *
     * Parses JSON-RPC request contained in `buf`, `len`.
     * Then, dispatches the request to the correct handler method.
     * Valid method names should be specified in NULL
     * terminated array `methods`, and corresponding handlers in `handlers`.
     * Result is put in `dst`, `dst_len`. Return: length of the result, which
     * can be larger then `dst_len` that indicates an overflow.
     * Overflown bytes are not written to the buffer.
     * If method is not found, an error is automatically generated.
     */
    int mg_rpc_dispatch(const char *buf, int, char *dst, int dst_len,
                        const char **methods, mg_rpc_handler_t *handlers);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_JSON_RPC_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  * This software is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http://www.gnu.org/licenses/>.
  *
  * You are free to use this software under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this software under a commercial
  * license, as set out in <https://www.cesanta.com/license>.
  */
 
 /*
  * === MQTT
  */
 
 #ifndef CS_MONGOOSE_SRC_MQTT_H_
 #define CS_MONGOOSE_SRC_MQTT_H_
 
 
 struct mg_mqtt_message {
    int cmd;
    struct mg_str payload;
    int qos;
    uint8_t connack_ret_code; /* connack */
    uint16_t message_id;      /* puback */
    char *topic;
 };
 
 struct mg_mqtt_topic_expression {
    const char *topic;
    uint8_t qos;
 };
 
 struct mg_send_mqtt_handshake_opts {
    unsigned char flags; /* connection flags */
    uint16_t keep_alive;
    const char *will_topic;
    const char *will_message;
    const char *user_name;
    const char *password;
 };
 
 /* Message types */
 #define MG_MQTT_CMD_CONNECT 1
 #define MG_MQTT_CMD_CONNACK 2
 #define MG_MQTT_CMD_PUBLISH 3
 #define MG_MQTT_CMD_PUBACK 4
 #define MG_MQTT_CMD_PUBREC 5
 #define MG_MQTT_CMD_PUBREL 6
 #define MG_MQTT_CMD_PUBCOMP 7
 #define MG_MQTT_CMD_SUBSCRIBE 8
 #define MG_MQTT_CMD_SUBACK 9
 #define MG_MQTT_CMD_UNSUBSCRIBE 10
 #define MG_MQTT_CMD_UNSUBACK 11
 #define MG_MQTT_CMD_PINGREQ 12
 #define MG_MQTT_CMD_PINGRESP 13
 #define MG_MQTT_CMD_DISCONNECT 14
 
 /* MQTT event types */
 #define MG_MQTT_EVENT_BASE 200
 #define MG_EV_MQTT_CONNECT (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_CONNECT)
 #define MG_EV_MQTT_CONNACK (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_CONNACK)
 #define MG_EV_MQTT_PUBLISH (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PUBLISH)
 #define MG_EV_MQTT_PUBACK (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PUBACK)
 #define MG_EV_MQTT_PUBREC (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PUBREC)
 #define MG_EV_MQTT_PUBREL (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PUBREL)
 #define MG_EV_MQTT_PUBCOMP (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PUBCOMP)
 #define MG_EV_MQTT_SUBSCRIBE (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_SUBSCRIBE)
 #define MG_EV_MQTT_SUBACK (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_SUBACK)
 #define MG_EV_MQTT_UNSUBSCRIBE (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_UNSUBSCRIBE)
 #define MG_EV_MQTT_UNSUBACK (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_UNSUBACK)
 #define MG_EV_MQTT_PINGREQ (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PINGREQ)
 #define MG_EV_MQTT_PINGRESP (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_PINGRESP)
 #define MG_EV_MQTT_DISCONNECT (MG_MQTT_EVENT_BASE + MG_MQTT_CMD_DISCONNECT)
 
 /* Message flags */
 #define MG_MQTT_RETAIN 0x1
 #define MG_MQTT_DUP 0x4
 #define MG_MQTT_QOS(qos) ((qos) << 1)
 #define MG_MQTT_GET_QOS(flags) (((flags) &0x6) >> 1)
 #define MG_MQTT_SET_QOS(flags, qos) (flags) = ((flags) & ~0x6) | ((qos) << 1)
 
 /* Connection flags */
 #define MG_MQTT_CLEAN_SESSION 0x02
 #define MG_MQTT_HAS_WILL 0x04
 #define MG_MQTT_WILL_RETAIN 0x20
 #define MG_MQTT_HAS_PASSWORD 0x40
 #define MG_MQTT_HAS_USER_NAME 0x80
 #define MG_MQTT_GET_WILL_QOS(flags) (((flags) &0x18) >> 3)
 #define MG_MQTT_SET_WILL_QOS(flags, qos) \
 (flags) = ((flags) & ~0x18) | ((qos) << 3)
 
 /* CONNACK return codes */
 #define MG_EV_MQTT_CONNACK_ACCEPTED 0
 #define MG_EV_MQTT_CONNACK_UNACCEPTABLE_VERSION 1
 #define MG_EV_MQTT_CONNACK_IDENTIFIER_REJECTED 2
 #define MG_EV_MQTT_CONNACK_SERVER_UNAVAILABLE 3
 #define MG_EV_MQTT_CONNACK_BAD_AUTH 4
 #define MG_EV_MQTT_CONNACK_NOT_AUTHORIZED 5
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /*
     * Attach built-in MQTT event handler to the given connection.
     *
     * The user-defined event handler will receive following extra events:
     *
     * - MG_EV_MQTT_CONNACK
     * - MG_EV_MQTT_PUBLISH
     * - MG_EV_MQTT_PUBACK
     * - MG_EV_MQTT_PUBREC
     * - MG_EV_MQTT_PUBREL
     * - MG_EV_MQTT_PUBCOMP
     * - MG_EV_MQTT_SUBACK
     */
    void mg_set_protocol_mqtt(struct mg_connection *nc);
    
    /* Send MQTT handshake. */
    void mg_send_mqtt_handshake(struct mg_connection *nc, const char *client_id);
    
    /* Send MQTT handshake with optional parameters. */
    void mg_send_mqtt_handshake_opt(struct mg_connection *nc, const char *client_id,
                                    struct mg_send_mqtt_handshake_opts);
    
    /* Publish a message to a given topic. */
    void mg_mqtt_publish(struct mg_connection *nc, const char *topic,
                         uint16_t message_id, int flags, const void *data,
                         size_t len);
    
    /* Subscribe to a bunch of topics. */
    void mg_mqtt_subscribe(struct mg_connection *nc,
                           const struct mg_mqtt_topic_expression *topics,
                           size_t topics_len, uint16_t message_id);
    
    /* Unsubscribe from a bunch of topics. */
    void mg_mqtt_unsubscribe(struct mg_connection *nc, char **topics,
                             size_t topics_len, uint16_t message_id);
    
    /* Send a DISCONNECT command. */
    void mg_mqtt_disconnect(struct mg_connection *nc);
    
    /* Send a CONNACK command with a given `return_code`. */
    void mg_mqtt_connack(struct mg_connection *nc, uint8_t return_code);
    
    /* Send a PUBACK command with a given `message_id`. */
    void mg_mqtt_puback(struct mg_connection *nc, uint16_t message_id);
    
    /* Send a PUBREC command with a given `message_id`. */
    void mg_mqtt_pubrec(struct mg_connection *nc, uint16_t message_id);
    
    /* Send a PUBREL command with a given `message_id`. */
    void mg_mqtt_pubrel(struct mg_connection *nc, uint16_t message_id);
    
    /* Send a PUBCOMP command with a given `message_id`. */
    void mg_mqtt_pubcomp(struct mg_connection *nc, uint16_t message_id);
    
    /*
     * Send a SUBACK command with a given `message_id`
     * and a sequence of granted QoSs.
     */
    void mg_mqtt_suback(struct mg_connection *nc, uint8_t *qoss, size_t qoss_len,
                        uint16_t message_id);
    
    /* Send a UNSUBACK command with a given `message_id`. */
    void mg_mqtt_unsuback(struct mg_connection *nc, uint16_t message_id);
    
    /* Send a PINGREQ command. */
    void mg_mqtt_ping(struct mg_connection *nc);
    
    /* Send a PINGRESP command. */
    void mg_mqtt_pong(struct mg_connection *nc);
    
    /*
     * Extract the next topic expression from a SUBSCRIBE command payload.
     *
     * Topic expression name will point to a string in the payload buffer.
     * Return the pos of the next topic expression or -1 when the list
     * of topics is exhausted.
     */
    int mg_mqtt_next_subscribe_topic(struct mg_mqtt_message *msg,
                                     struct mg_str *topic, uint8_t *qos, int pos);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* CS_MONGOOSE_SRC_MQTT_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  * This software is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http://www.gnu.org/licenses/>.
  *
  * You are free to use this software under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this software under a commercial
  * license, as set out in <https://www.cesanta.com/license>.
  */
 
 /*
  * === MQTT Broker
  */
 
 #ifndef CS_MONGOOSE_SRC_MQTT_BROKER_H_
 #define CS_MONGOOSE_SRC_MQTT_BROKER_H_
 
 #ifdef MG_ENABLE_MQTT_BROKER
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #define MG_MQTT_MAX_SESSION_SUBSCRIPTIONS 512;
    
    struct mg_mqtt_broker;
    
    /* MQTT session (Broker side). */
    struct mg_mqtt_session {
       struct mg_mqtt_broker *brk;          /* Broker */
       struct mg_mqtt_session *next, *prev; /* mg_mqtt_broker::sessions linkage */
       struct mg_connection *nc;            /* Connection with the client */
       size_t num_subscriptions;            /* Size of `subscriptions` array */
       struct mg_mqtt_topic_expression *subscriptions;
       void *user_data; /* User data */
    };
    
    /* MQTT broker. */
    struct mg_mqtt_broker {
       struct mg_mqtt_session *sessions; /* Session list */
       void *user_data;                  /* User data */
    };
    
    /* Initialize a MQTT broker. */
    void mg_mqtt_broker_init(struct mg_mqtt_broker *brk, void *user_data);
    
    /*
     * Process a MQTT broker message.
     *
     * Listening connection expects a pointer to an initialized `mg_mqtt_broker`
     * structure in the `user_data` field.
     *
     * Basic usage:
     *
     * ```c
     * mg_mqtt_broker_init(&brk, NULL);
     *
     * if ((nc = mg_bind(&mgr, address, mg_mqtt_broker)) == NULL) {
     *   // fail;
     * }
     * nc->user_data = &brk;
     * ```
     *
     * New incoming connections will receive a `mg_mqtt_session` structure
     * in the connection `user_data`. The original `user_data` will be stored
     * in the `user_data` field of the session structure. This allows the user
     * handler to store user data before `mg_mqtt_broker` creates the session.
     *
     * Since only the MG_EV_ACCEPT message is processed by the listening socket,
     * for most events the `user_data` will thus point to a `mg_mqtt_session`.
     */
    void mg_mqtt_broker(struct mg_connection *brk, int ev, void *data);
    
    /*
     * Iterate over all mqtt sessions connections. Example:
     *
     * ```c
     * struct mg_mqtt_session *s;
     * for (s = mg_mqtt_next(brk, NULL); s != NULL; s = mg_mqtt_next(brk, s)) {
     *   // Do something
     * }
     * ```
     */
    struct mg_mqtt_session *mg_mqtt_next(struct mg_mqtt_broker *brk,
                                         struct mg_mqtt_session *s);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* MG_ENABLE_MQTT_BROKER */
 #endif /* CS_MONGOOSE_SRC_MQTT_BROKER_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === DNS
  */
 
 #ifndef CS_MONGOOSE_SRC_DNS_H_
 #define CS_MONGOOSE_SRC_DNS_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #define MG_DNS_A_RECORD 0x01     /* Lookup IP address */
 #define MG_DNS_CNAME_RECORD 0x05 /* Lookup CNAME */
 #define MG_DNS_AAAA_RECORD 0x1c  /* Lookup IPv6 address */
 #define MG_DNS_MX_RECORD 0x0f    /* Lookup mail server for domain */
    
 #define MG_MAX_DNS_QUESTIONS 32
 #define MG_MAX_DNS_ANSWERS 32
    
 #define MG_DNS_MESSAGE 100 /* High-level DNS message event */
    
    enum mg_dns_resource_record_kind {
       MG_DNS_INVALID_RECORD = 0,
       MG_DNS_QUESTION,
       MG_DNS_ANSWER
    };
    
    /* DNS resource record. */
    struct mg_dns_resource_record {
       struct mg_str name; /* buffer with compressed name */
       int rtype;
       int rclass;
       int ttl;
       enum mg_dns_resource_record_kind kind;
       struct mg_str rdata; /* protocol data (can be a compressed name) */
    };
    
    /* DNS message (request and response). */
    struct mg_dns_message {
       struct mg_str pkt; /* packet body */
       uint16_t flags;
       uint16_t transaction_id;
       int num_questions;
       int num_answers;
       struct mg_dns_resource_record questions[MG_MAX_DNS_QUESTIONS];
       struct mg_dns_resource_record answers[MG_MAX_DNS_ANSWERS];
    };
    
    struct mg_dns_resource_record *mg_dns_next_record(
                                                      struct mg_dns_message *msg, int query, struct mg_dns_resource_record *prev);
    
    /*
     * Parse the record data from a DNS resource record.
     *
     *  - A:     struct in_addr *ina
     *  - AAAA:  struct in6_addr *ina
     *  - CNAME: char buffer
     *
     * Returns -1 on error.
     *
     * TODO(mkm): MX
     */
    int mg_dns_parse_record_data(struct mg_dns_message *msg,
                                 struct mg_dns_resource_record *rr, void *data,
                                 size_t data_len);
    
    /*
     * Send a DNS query to the remote end.
     */
    void mg_send_dns_query(struct mg_connection *nc, const char *name,
                           int query_type);
    
    /*
     * Insert a DNS header to an IO buffer.
     *
     * Return number of bytes inserted.
     */
    int mg_dns_insert_header(struct mbuf *io, size_t pos,
                             struct mg_dns_message *msg);
    
    /*
     * Append already encoded questions from an existing message.
     *
     * This is useful when generating a DNS reply message which includes
     * all question records.
     *
     * Return number of appened bytes.
     */
    int mg_dns_copy_questions(struct mbuf *io, struct mg_dns_message *msg);
    
    /*
     * Encode and append a DNS resource record to an IO buffer.
     *
     * The record metadata is taken from the `rr` parameter, while the name and data
     * are taken from the parameters, encoded in the appropriate format depending on
     * record type, and stored in the IO buffer. The encoded values might contain
     * offsets within the IO buffer. It's thus important that the IO buffer doesn't
     * get trimmed while a sequence of records are encoded while preparing a DNS
     *reply.
     *
     * This function doesn't update the `name` and `rdata` pointers in the `rr`
     *struct
     * because they might be invalidated as soon as the IO buffer grows again.
     *
     * Return the number of bytes appened or -1 in case of error.
     */
    int mg_dns_encode_record(struct mbuf *io, struct mg_dns_resource_record *rr,
                             const char *name, size_t nlen, const void *rdata,
                             size_t rlen);
    
    /* Low-level: parses a DNS response. */
    int mg_parse_dns(const char *buf, int len, struct mg_dns_message *msg);
    
    /*
     * Uncompress a DNS compressed name.
     *
     * The containing dns message is required because the compressed encoding
     * and reference suffixes present elsewhere in the packet.
     *
     * If name is less than `dst_len` characters long, the remainder
     * of `dst` is terminated with `\0' characters. Otherwise, `dst` is not
     *terminated.
     *
     * If `dst_len` is 0 `dst` can be NULL.
     * Return the uncompressed name length.
     */
    size_t mg_dns_uncompress_name(struct mg_dns_message *msg, struct mg_str *name,
                                  char *dst, int dst_len);
    
    /*
     * Attach built-in DNS event handler to the given listening connection.
     *
     * DNS event handler parses incoming UDP packets, treating them as DNS
     * requests. If incoming packet gets successfully parsed by the DNS event
     * handler, a user event handler will receive `MG_DNS_REQUEST` event, with
     * `ev_data` pointing to the parsed `struct mg_dns_message`.
     *
     * See
     * [captive_dns_server](https://github.com/cesanta/mongoose/tree/master/examples/captive_dns_server)
     * example on how to handle DNS request and send DNS reply.
     */
    void mg_set_protocol_dns(struct mg_connection *nc);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_DNS_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === DNS server
  *
  * Disabled by default; enable with `-DMG_ENABLE_DNS_SERVER`.
  */
 
 #ifndef CS_MONGOOSE_SRC_DNS_SERVER_H_
 #define CS_MONGOOSE_SRC_DNS_SERVER_H_
 
 #ifdef MG_ENABLE_DNS_SERVER
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
 #define MG_DNS_SERVER_DEFAULT_TTL 3600
    
    struct mg_dns_reply {
       struct mg_dns_message *msg;
       struct mbuf *io;
       size_t start;
    };
    
    /*
     * Create a DNS reply.
     *
     * The reply will be based on an existing query message `msg`.
     * The query body will be appended to the output buffer.
     * "reply + recursion allowed" will be added to the message flags and
     * message's num_answers will be set to 0.
     *
     * Answer records can be appended with `mg_dns_send_reply` or by lower
     * level function defined in the DNS API.
     *
     * In order to send the reply use `mg_dns_send_reply`.
     * It's possible to use a connection's send buffer as reply buffers,
     * and it will work for both UDP and TCP connections.
     *
     * Example:
     *
     * ```c
     * reply = mg_dns_create_reply(&nc->send_mbuf, msg);
     * for (i = 0; i < msg->num_questions; i++) {
     *   rr = &msg->questions[i];
     *   if (rr->rtype == MG_DNS_A_RECORD) {
     *     mg_dns_reply_record(&reply, rr, 3600, &dummy_ip_addr, 4);
     *   }
     * }
     * mg_dns_send_reply(nc, &reply);
     * ```
     */
    struct mg_dns_reply mg_dns_create_reply(struct mbuf *io,
                                            struct mg_dns_message *msg);
    
    /*
     * Append a DNS reply record to the IO buffer and to the DNS message.
     *
     * The message num_answers field will be incremented. It's caller's duty
     * to ensure num_answers is propertly initialized.
     *
     * Returns -1 on error.
     */
    int mg_dns_reply_record(struct mg_dns_reply *reply,
                            struct mg_dns_resource_record *question,
                            const char *name, int rtype, int ttl, const void *rdata,
                            size_t rdata_len);
    
    /*
     * Send a DNS reply through a connection.
     *
     * The DNS data is stored in an IO buffer pointed by reply structure in `r`.
     * This function mutates the content of that buffer in order to ensure that
     * the DNS header reflects size and flags of the mssage, that might have been
     * updated either with `mg_dns_reply_record` or by direct manipulation of
     * `r->message`.
     *
     * Once sent, the IO buffer will be trimmed unless the reply IO buffer
     * is the connection's send buffer and the connection is not in UDP mode.
     */
    void mg_dns_send_reply(struct mg_connection *nc, struct mg_dns_reply *r);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* MG_ENABLE_DNS_SERVER */
 #endif /* CS_MONGOOSE_SRC_DNS_SERVER_H_ */
 /*
  * Copyright (c) 2014 Cesanta Software Limited
  * All rights reserved
  */
 
 /*
  * === Asynchronouns DNS resolver
  */
 
 #ifndef CS_MONGOOSE_SRC_RESOLV_H_
 #define CS_MONGOOSE_SRC_RESOLV_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    enum mg_resolve_err {
       MG_RESOLVE_OK = 0,
       MG_RESOLVE_NO_ANSWERS = 1,
       MG_RESOLVE_EXCEEDED_RETRY_COUNT = 2,
       MG_RESOLVE_TIMEOUT = 3
    };
    
    typedef void (*mg_resolve_callback_t)(struct mg_dns_message *dns_message,
    void *user_data, enum mg_resolve_err);
    
    /* Options for `mg_resolve_async_opt`. */
    struct mg_resolve_async_opts {
       const char *nameserver_url;
       int max_retries;    /* defaults to 2 if zero */
       int timeout;        /* in seconds; defaults to 5 if zero */
       int accept_literal; /* pseudo-resolve literal ipv4 and ipv6 addrs */
       int only_literal;   /* only resolves literal addrs; sync cb invocation */
       struct mg_connection **dns_conn; /* return DNS connection */
    };
    
    /* See `mg_resolve_async_opt()` */
    int mg_resolve_async(struct mg_mgr *mgr, const char *name, int query,
                         mg_resolve_callback_t cb, void *data);
    
    /*
     * Resolved a DNS name asynchronously.
     *
     * Upon successful resolution, the user callback will be invoked
     * with the full DNS response message and a pointer to the user's
     * context `data`.
     *
     * In case of timeout while performing the resolution the callback
     * will receive a NULL `msg`.
     *
     * The DNS answers can be extracted with `mg_next_record` and
     * `mg_dns_parse_record_data`:
     *
     * [source,c]
     * ----
     * struct in_addr ina;
     * struct mg_dns_resource_record *rr = mg_next_record(msg, MG_DNS_A_RECORD,
     *   NULL);
     * mg_dns_parse_record_data(msg, rr, &ina, sizeof(ina));
     * ----
     */
    int mg_resolve_async_opt(struct mg_mgr *mgr, const char *name, int query,
                             mg_resolve_callback_t cb, void *data,
                             struct mg_resolve_async_opts opts);
    
    /*
     * Resolve a name from `/etc/hosts`.
     *
     * Returns 0 on success, -1 on failure.
     */
    int mg_resolve_from_hosts_file(const char *host, union socket_address *usa);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* CS_MONGOOSE_SRC_RESOLV_H_ */
 /*
  * Copyright (c) 2015 Cesanta Software Limited
  * All rights reserved
  * This software is dual-licensed: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation. For the terms of this
  * license, see <http://www.gnu.org/licenses/>.
  *
  * You are free to use this software under the terms of the GNU General
  * Public License, 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.
  *
  * Alternatively, you can license this software under a commercial
  * license, as set out in <https://www.cesanta.com/license>.
  */
 
 /*
  * === CoAP
  *
  * CoAP message format:
  *
  * ```
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
  * |Ver| T | TKL | Code | Message ID | Token (if any, TKL bytes) ...
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
  * | Options (if any) ...            |1 1 1 1 1 1 1 1| Payload (if any) ...
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
  * ```
  */
 
 #ifndef CS_MONGOOSE_SRC_COAP_H_
 #define CS_MONGOOSE_SRC_COAP_H_
 
 #ifdef MG_ENABLE_COAP
 
 #define MG_COAP_MSG_TYPE_FIELD 0x2
 #define MG_COAP_CODE_CLASS_FIELD 0x4
 #define MG_COAP_CODE_DETAIL_FIELD 0x8
 #define MG_COAP_MSG_ID_FIELD 0x10
 #define MG_COAP_TOKEN_FIELD 0x20
 #define MG_COAP_OPTIOMG_FIELD 0x40
 #define MG_COAP_PAYLOAD_FIELD 0x80
 
 #define MG_COAP_ERROR 0x10000
 #define MG_COAP_FORMAT_ERROR (MG_COAP_ERROR | 0x20000)
 #define MG_COAP_IGNORE (MG_COAP_ERROR | 0x40000)
 #define MG_COAP_NOT_ENOUGH_DATA (MG_COAP_ERROR | 0x80000)
 #define MG_COAP_NETWORK_ERROR (MG_COAP_ERROR | 0x100000)
 
 #define MG_COAP_MSG_CON 0
 #define MG_COAP_MSG_NOC 1
 #define MG_COAP_MSG_ACK 2
 #define MG_COAP_MSG_RST 3
 #define MG_COAP_MSG_MAX 3
 
 #define MG_COAP_CODECLASS_REQUEST 0
 #define MG_COAP_CODECLASS_RESP_OK 2
 #define MG_COAP_CODECLASS_CLIENT_ERR 4
 #define MG_COAP_CODECLASS_SRV_ERR 5
 
 #define MG_COAP_EVENT_BASE 300
 #define MG_EV_COAP_CON (MG_COAP_EVENT_BASE + MG_COAP_MSG_CON)
 #define MG_EV_COAP_NOC (MG_COAP_EVENT_BASE + MG_COAP_MSG_NOC)
 #define MG_EV_COAP_ACK (MG_COAP_EVENT_BASE + MG_COAP_MSG_ACK)
 #define MG_EV_COAP_RST (MG_COAP_EVENT_BASE + MG_COAP_MSG_RST)
 
 /*
  * CoAP options.
  * Use mg_coap_add_option and mg_coap_free_options
  * for creation and destruction.
  */
 struct mg_coap_option {
    struct mg_coap_option *next;
    uint32_t number;
    struct mg_str value;
 };
 
 /* CoAP message. See RFC 7252 for details. */
 struct mg_coap_message {
    uint32_t flags;
    uint8_t msg_type;
    uint8_t code_class;
    uint8_t code_detail;
    uint16_t msg_id;
    struct mg_str token;
    struct mg_coap_option *options;
    struct mg_str payload;
    struct mg_coap_option *optiomg_tail;
 };
 
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
    
    /* Set CoAP protocol handler - trigger CoAP specific events */
    int mg_set_protocol_coap(struct mg_connection *nc);
    
    /*
     * Add new option to mg_coap_message structure.
     * Returns pointer to the newly created option.
     */
    struct mg_coap_option *mg_coap_add_option(struct mg_coap_message *cm,
                                              uint32_t number, char *value,
                                              size_t len);
    
    /*
     * Free the memory allocated for options,
     * if cm paramater doesn't contain any option does nothing.
     */
    void mg_coap_free_options(struct mg_coap_message *cm);
    
    /*
     * Compose CoAP message from `mg_coap_message`
     * and send it into `nc` connection.
     * Return 0 on success. On error, it is a bitmask:
     *
     * - `#define MG_COAP_ERROR 0x10000`
     * - `#define MG_COAP_FORMAT_ERROR (MG_COAP_ERROR | 0x20000)`
     * - `#define MG_COAP_IGNORE (MG_COAP_ERROR | 0x40000)`
     * - `#define MG_COAP_NOT_ENOUGH_DATA (MG_COAP_ERROR | 0x80000)`
     * - `#define MG_COAP_NETWORK_ERROR (MG_COAP_ERROR | 0x100000)`
     */
    uint32_t mg_coap_send_message(struct mg_connection *nc,
                                  struct mg_coap_message *cm);
    
    /*
     * Compose CoAP acknowledgement from `mg_coap_message`
     * and send it into `nc` connection.
     * Return value: see `mg_coap_send_message()`
     */
    uint32_t mg_coap_send_ack(struct mg_connection *nc, uint16_t msg_id);
    
    /*
     * Parse COAP message and fills mg_coap_message and returns cm->flags.
     * This is a helper function.
     *
     * NOTE: usually CoAP work over UDP, so lack of data means format error,
     * but in theory it is possible to use CoAP over TCP (according to RFC)
     *
     * The caller have to check results and treat COAP_NOT_ENOUGH_DATA according to
     * underlying protocol:
     *
     * - in case of UDP COAP_NOT_ENOUGH_DATA means COAP_FORMAT_ERROR,
     * - in case of TCP client can try to receive more data
     *
     * Return value: see `mg_coap_send_message()`
     */
    uint32_t mg_coap_parse(struct mbuf *io, struct mg_coap_message *cm);
    
    /*
     * Composes CoAP message from mg_coap_message structure.
     * This is a helper function.
     * Return value: see `mg_coap_send_message()`
     */
    uint32_t mg_coap_compose(struct mg_coap_message *cm, struct mbuf *io);
    
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 
 #endif /* MG_ENABLE_COAP */
 
 #endif /* CS_MONGOOSE_SRC_COAP_H_ */