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feat: Full featured Telnet implementation (not integrated)

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Gustice
2025-11-13 00:24:43 +01:00
parent 3afaf3848f
commit bd4a593963
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managed_components/frozen-eye__esp_telnet/src/libtelnet.c
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managed_components/frozen-eye__esp_telnet/src/libtelnet.h
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/*!
* \brief libtelnet - TELNET protocol handling library
*
* SUMMARY:
*
* libtelnet is a library for handling the TELNET protocol. It includes
* routines for parsing incoming data from a remote peer as well as formatting
* data to send to the remote peer.
*
* libtelnet uses a callback-oriented API, allowing application-specific
* handling of various events. The callback system is also used for buffering
* outgoing protocol data, allowing the application to maintain control over
* the actual socket connection.
*
* Features supported include the full TELNET protocol, Q-method option
* negotiation, ZMP, MCCP2, MSSP, and NEW-ENVIRON.
*
* CONFORMS TO:
*
* RFC854 - http://www.faqs.org/rfcs/rfc854.html
* RFC855 - http://www.faqs.org/rfcs/rfc855.html
* RFC1091 - http://www.faqs.org/rfcs/rfc1091.html
* RFC1143 - http://www.faqs.org/rfcs/rfc1143.html
* RFC1408 - http://www.faqs.org/rfcs/rfc1408.html
* RFC1572 - http://www.faqs.org/rfcs/rfc1572.html
*
* LICENSE:
*
* The author or authors of this code dedicate any and all copyright interest
* in this code to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and successors. We
* intend this dedication to be an overt act of relinquishment in perpetuity of
* all present and future rights to this code under copyright law.
*
* \file libtelnet.h
*
* \version 0.23
*
* \author Sean Middleditch <sean@sourcemud.org>
*/
#if !defined(LIBTELNET_INCLUDE)
#define LIBTELNET_INCLUDE 1
/* standard C headers necessary for the libtelnet API */
#include <stdarg.h>
#include <stddef.h>
/* C++ support */
#if defined(__cplusplus)
extern "C" {
#endif
/* printf type checking feature in GCC and some other compilers */
#if __GNUC__
# define TELNET_GNU_PRINTF(f,a) __attribute__((format(printf, f, a))) /*!< internal helper */
# define TELNET_GNU_SENTINEL __attribute__((sentinel)) /*!< internal helper */
#else
# define TELNET_GNU_PRINTF(f,a) /*!< internal helper */
# define TELNET_GNU_SENTINEL /*!< internal helper */
#endif
/* Disable environ macro for Visual C++ 2015. */
#undef environ
/*! Telnet state tracker object type. */
typedef struct telnet_t telnet_t;
/*! Telnet event object type. */
typedef union telnet_event_t telnet_event_t;
/*! Telnet option table element type. */
typedef struct telnet_telopt_t telnet_telopt_t;
/*! \name Telnet commands */
/*@{*/
/*! Telnet commands and special values. */
#define TELNET_IAC 255
#define TELNET_DONT 254
#define TELNET_DO 253
#define TELNET_WONT 252
#define TELNET_WILL 251
#define TELNET_SB 250
#define TELNET_GA 249
#define TELNET_EL 248
#define TELNET_EC 247
#define TELNET_AYT 246
#define TELNET_AO 245
#define TELNET_IP 244
#define TELNET_BREAK 243
#define TELNET_DM 242
#define TELNET_NOP 241
#define TELNET_SE 240
#define TELNET_EOR 239
#define TELNET_ABORT 238
#define TELNET_SUSP 237
#define TELNET_EOF 236
/*@}*/
/*! \name Telnet option values. */
/*@{*/
/*! Telnet options. */
#define TELNET_TELOPT_BINARY 0
#define TELNET_TELOPT_ECHO 1
#define TELNET_TELOPT_RCP 2
#define TELNET_TELOPT_SGA 3
#define TELNET_TELOPT_NAMS 4
#define TELNET_TELOPT_STATUS 5
#define TELNET_TELOPT_TM 6
#define TELNET_TELOPT_RCTE 7
#define TELNET_TELOPT_NAOL 8
#define TELNET_TELOPT_NAOP 9
#define TELNET_TELOPT_NAOCRD 10
#define TELNET_TELOPT_NAOHTS 11
#define TELNET_TELOPT_NAOHTD 12
#define TELNET_TELOPT_NAOFFD 13
#define TELNET_TELOPT_NAOVTS 14
#define TELNET_TELOPT_NAOVTD 15
#define TELNET_TELOPT_NAOLFD 16
#define TELNET_TELOPT_XASCII 17
#define TELNET_TELOPT_LOGOUT 18
#define TELNET_TELOPT_BM 19
#define TELNET_TELOPT_DET 20
#define TELNET_TELOPT_SUPDUP 21
#define TELNET_TELOPT_SUPDUPOUTPUT 22
#define TELNET_TELOPT_SNDLOC 23
#define TELNET_TELOPT_TTYPE 24
#define TELNET_TELOPT_EOR 25
#define TELNET_TELOPT_TUID 26
#define TELNET_TELOPT_OUTMRK 27
#define TELNET_TELOPT_TTYLOC 28
#define TELNET_TELOPT_3270REGIME 29
#define TELNET_TELOPT_X3PAD 30
#define TELNET_TELOPT_NAWS 31
#define TELNET_TELOPT_TSPEED 32
#define TELNET_TELOPT_LFLOW 33
#define TELNET_TELOPT_LINEMODE 34
#define TELNET_TELOPT_XDISPLOC 35
#define TELNET_TELOPT_ENVIRON 36
#define TELNET_TELOPT_AUTHENTICATION 37
#define TELNET_TELOPT_ENCRYPT 38
#define TELNET_TELOPT_NEW_ENVIRON 39
#define TELNET_TELOPT_MSSP 70
#define TELNET_TELOPT_COMPRESS 85
#define TELNET_TELOPT_COMPRESS2 86
#define TELNET_TELOPT_ZMP 93
#define TELNET_TELOPT_EXOPL 255
#define TELNET_TELOPT_MCCP2 86
/*@}*/
/*! \name Protocol codes for TERMINAL-TYPE commands. */
/*@{*/
/*! TERMINAL-TYPE codes. */
#define TELNET_TTYPE_IS 0
#define TELNET_TTYPE_SEND 1
/*@}*/
/*! \name Protocol codes for NEW-ENVIRON/ENVIRON commands. */
/*@{*/
/*! NEW-ENVIRON/ENVIRON codes. */
#define TELNET_ENVIRON_IS 0
#define TELNET_ENVIRON_SEND 1
#define TELNET_ENVIRON_INFO 2
#define TELNET_ENVIRON_VAR 0
#define TELNET_ENVIRON_VALUE 1
#define TELNET_ENVIRON_ESC 2
#define TELNET_ENVIRON_USERVAR 3
/*@}*/
/*! \name Protocol codes for MSSP commands. */
/*@{*/
/*! MSSP codes. */
#define TELNET_MSSP_VAR 1
#define TELNET_MSSP_VAL 2
/*@}*/
/*! \name Telnet state tracker flags. */
/*@{*/
/*! Control behavior of telnet state tracker. */
#define TELNET_FLAG_PROXY (1<<0)
#define TELNET_FLAG_NVT_EOL (1<<1)
/* Internal-only bits in option flags */
#define TELNET_FLAG_TRANSMIT_BINARY (1<<5)
#define TELNET_FLAG_RECEIVE_BINARY (1<<6)
#define TELNET_PFLAG_DEFLATE (1<<7)
/*@}*/
/*!
* error codes
*/
enum telnet_error_t {
TELNET_EOK = 0, /*!< no error */
TELNET_EBADVAL, /*!< invalid parameter, or API misuse */
TELNET_ENOMEM, /*!< memory allocation failure */
TELNET_EOVERFLOW, /*!< data exceeds buffer size */
TELNET_EPROTOCOL, /*!< invalid sequence of special bytes */
TELNET_ECOMPRESS /*!< error handling compressed streams */
};
typedef enum telnet_error_t telnet_error_t; /*!< Error code type. */
/*!
* event codes
*/
enum telnet_event_type_t {
TELNET_EV_DATA = 0, /*!< raw text data has been received */
TELNET_EV_SEND, /*!< data needs to be sent to the peer */
TELNET_EV_IAC, /*!< generic IAC code received */
TELNET_EV_WILL, /*!< WILL option negotiation received */
TELNET_EV_WONT, /*!< WONT option neogitation received */
TELNET_EV_DO, /*!< DO option negotiation received */
TELNET_EV_DONT, /*!< DONT option negotiation received */
TELNET_EV_SUBNEGOTIATION, /*!< sub-negotiation data received */
TELNET_EV_COMPRESS, /*!< compression has been enabled */
TELNET_EV_ZMP, /*!< ZMP command has been received */
TELNET_EV_TTYPE, /*!< TTYPE command has been received */
TELNET_EV_ENVIRON, /*!< ENVIRON command has been received */
TELNET_EV_MSSP, /*!< MSSP command has been received */
TELNET_EV_WARNING, /*!< recoverable error has occured */
TELNET_EV_ERROR /*!< non-recoverable error has occured */
};
typedef enum telnet_event_type_t telnet_event_type_t; /*!< Telnet event type. */
/*!
* environ/MSSP command information
*/
struct telnet_environ_t {
unsigned char type; /*!< either TELNET_ENVIRON_VAR or TELNET_ENVIRON_USERVAR */
char *var; /*!< name of the variable being set */
char *value; /*!< value of variable being set; empty string if no value */
};
/*!
* event information
*/
union telnet_event_t {
/*!
* \brief Event type
*
* The type field will determine which of the other event structure fields
* have been filled in. For instance, if the event type is TELNET_EV_ZMP,
* then the zmp event field (and ONLY the zmp event field) will be filled
* in.
*/
enum telnet_event_type_t type;
/*!
* data event: for DATA and SEND events
*/
struct data_t {
enum telnet_event_type_t _type; /*!< alias for type */
const char *buffer; /*!< byte buffer */
size_t size; /*!< number of bytes in buffer */
} data; /*!< DATA and SEND */
/*!
* WARNING and ERROR events
*/
struct error_t {
enum telnet_event_type_t _type; /*!< alias for type */
const char *file; /*!< file the error occured in */
const char *func; /*!< function the error occured in */
const char *msg; /*!< error message string */
int line; /*!< line of file error occured on */
telnet_error_t errcode; /*!< error code */
} error; /*!< WARNING and ERROR */
/*!
* command event: for IAC
*/
struct iac_t {
enum telnet_event_type_t _type; /*!< alias for type */
unsigned char cmd; /*!< telnet command received */
} iac; /*!< IAC */
/*!
* negotiation event: WILL, WONT, DO, DONT
*/
struct negotiate_t {
enum telnet_event_type_t _type; /*!< alias for type */
unsigned char telopt; /*!< option being negotiated */
} neg; /*!< WILL, WONT, DO, DONT */
/*!
* subnegotiation event
*/
struct subnegotiate_t {
enum telnet_event_type_t _type; /*!< alias for type */
const char *buffer; /*!< data of sub-negotiation */
size_t size; /*!< number of bytes in buffer */
unsigned char telopt; /*!< option code for negotiation */
} sub; /*!< SB */
/*!
* ZMP event
*/
struct zmp_t {
enum telnet_event_type_t _type; /*!< alias for type */
const char **argv; /*!< array of argument string */
size_t argc; /*!< number of elements in argv */
} zmp; /*!< ZMP */
/*!
* TTYPE event
*/
struct ttype_t {
enum telnet_event_type_t _type; /*!< alias for type */
unsigned char cmd; /*!< TELNET_TTYPE_IS or TELNET_TTYPE_SEND */
const char* name; /*!< terminal type name (IS only) */
} ttype; /*!< TTYPE */
/*!
* COMPRESS event
*/
struct compress_t {
enum telnet_event_type_t _type; /*!< alias for type */
unsigned char state; /*!< 1 if compression is enabled,
0 if disabled */
} compress; /*!< COMPRESS */
/*!
* ENVIRON/NEW-ENVIRON event
*/
struct environ_t {
enum telnet_event_type_t _type; /*!< alias for type */
const struct telnet_environ_t *values; /*!< array of variable values */
size_t size; /*!< number of elements in values */
unsigned char cmd; /*!< SEND, IS, or INFO */
} environ; /*!< ENVIRON, NEW-ENVIRON */
/*!
* MSSP event
*/
struct mssp_t {
enum telnet_event_type_t _type; /*!< alias for type */
const struct telnet_environ_t *values; /*!< array of variable values */
size_t size; /*!< number of elements in values */
} mssp; /*!< MSSP */
};
/*!
* \brief event handler
*
* This is the type of function that must be passed to
* telnet_init() when creating a new telnet object. The
* function will be invoked once for every event generated
* by the libtelnet protocol parser.
*
* \param telnet The telnet object that generated the event
* \param event Event structure with details about the event
* \param user_data User-supplied pointer
*/
typedef void (*telnet_event_handler_t)(telnet_t *telnet,
telnet_event_t *event, void *user_data);
/*!
* telopt support table element; use telopt of -1 for end marker
*/
struct telnet_telopt_t {
short telopt; /*!< one of the TELOPT codes or -1 */
unsigned char us; /*!< TELNET_WILL or TELNET_WONT */
unsigned char him; /*!< TELNET_DO or TELNET_DONT */
};
/*!
* state tracker -- private data structure
*/
struct telnet_t;
/*!
* \brief Initialize a telnet state tracker.
*
* This function initializes a new state tracker, which is used for all
* other libtelnet functions. Each connection must have its own
* telnet state tracker object.
*
* \param telopts Table of TELNET options the application supports.
* \param eh Event handler function called for every event.
* \param flags 0 or TELNET_FLAG_PROXY.
* \param user_data Optional data pointer that will be passsed to eh.
* \return Telnet state tracker object.
*/
extern telnet_t* telnet_init(const telnet_telopt_t *telopts,
telnet_event_handler_t eh, unsigned char flags, void *user_data);
/*!
* \brief Free up any memory allocated by a state tracker.
*
* This function must be called when a telnet state tracker is no
* longer needed (such as after the connection has been closed) to
* release any memory resources used by the state tracker.
*
* \param telnet Telnet state tracker object.
*/
extern void telnet_free(telnet_t *telnet);
/*!
* \brief Push a byte buffer into the state tracker.
*
* Passes one or more bytes to the telnet state tracker for
* protocol parsing. The byte buffer is most often going to be
* the buffer that recv() was called for while handling the
* connection.
*
* \param telnet Telnet state tracker object.
* \param buffer Pointer to byte buffer.
* \param size Number of bytes pointed to by buffer.
*/
extern void telnet_recv(telnet_t *telnet, const char *buffer,
size_t size);
/*!
* \brief Send a telnet command.
*
* \param telnet Telnet state tracker object.
* \param cmd Command to send.
*/
extern void telnet_iac(telnet_t *telnet, unsigned char cmd);
/*!
* \brief Send negotiation command.
*
* Internally, libtelnet uses RFC1143 option negotiation rules.
* The negotiation commands sent with this function may be ignored
* if they are determined to be redundant.
*
* \param telnet Telnet state tracker object.
* \param cmd TELNET_WILL, TELNET_WONT, TELNET_DO, or TELNET_DONT.
* \param opt One of the TELNET_TELOPT_* values.
*/
extern void telnet_negotiate(telnet_t *telnet, unsigned char cmd,
unsigned char opt);
/*!
* Send non-command data (escapes IAC bytes).
*
* \param telnet Telnet state tracker object.
* \param buffer Buffer of bytes to send.
* \param size Number of bytes to send.
*/
extern void telnet_send(telnet_t *telnet,
const char *buffer, size_t size);
/*!
* Send non-command text (escapes IAC bytes and translates
* \\r -> CR-NUL and \\n -> CR-LF unless in BINARY mode.
*
* \param telnet Telnet state tracker object.
* \param buffer Buffer of bytes to send.
* \param size Number of bytes to send.
*/
extern void telnet_send_text(telnet_t *telnet,
const char *buffer, size_t size);
/*!
* \brief Begin a sub-negotiation command.
*
* Sends IAC SB followed by the telopt code. All following data sent
* will be part of the sub-negotiation, until telnet_finish_sb() is
* called.
*
* \param telnet Telnet state tracker object.
* \param telopt One of the TELNET_TELOPT_* values.
*/
extern void telnet_begin_sb(telnet_t *telnet,
unsigned char telopt);
/*!
* \brief Finish a sub-negotiation command.
*
* This must be called after a call to telnet_begin_sb() to finish a
* sub-negotiation command.
*
* \param telnet Telnet state tracker object.
*/
#define telnet_finish_sb(telnet) telnet_iac((telnet), TELNET_SE)
/*!
* \brief Shortcut for sending a complete subnegotiation buffer.
*
* Equivalent to:
* telnet_begin_sb(telnet, telopt);
* telnet_send(telnet, buffer, size);
* telnet_finish_sb(telnet);
*
* \param telnet Telnet state tracker format.
* \param telopt One of the TELNET_TELOPT_* values.
* \param buffer Byte buffer for sub-negotiation data.
* \param size Number of bytes to use for sub-negotiation data.
*/
extern void telnet_subnegotiation(telnet_t *telnet, unsigned char telopt,
const char *buffer, size_t size);
/*!
* \brief Begin sending compressed data.
*
* This function will begein sending data using the COMPRESS2 option,
* which enables the use of zlib to compress data sent to the client.
* The client must offer support for COMPRESS2 with option negotiation,
* and zlib support must be compiled into libtelnet.
*
* Only the server may call this command.
*
* \param telnet Telnet state tracker object.
*/
extern void telnet_begin_compress2(telnet_t *telnet);
/*!
* \brief Send formatted data.
*
* This function is a wrapper around telnet_send(). It allows using
* printf-style formatting.
*
* Additionally, this function will translate \\r to the CR NUL construct and
* \\n with CR LF, as well as automatically escaping IAC bytes like
* telnet_send().
*
* \param telnet Telnet state tracker object.
* \param fmt Format string.
* \return Number of bytes sent.
*/
extern int telnet_printf(telnet_t *telnet, const char *fmt, ...)
TELNET_GNU_PRINTF(2, 3);
/*!
* \brief Send formatted data.
*
* See telnet_printf().
*/
extern int telnet_vprintf(telnet_t *telnet, const char *fmt, va_list va);
/*!
* \brief Send formatted data (no newline escaping).
*
* This behaves identically to telnet_printf(), except that the \\r and \\n
* characters are not translated. The IAC byte is still escaped as normal
* with telnet_send().
*
* \param telnet Telnet state tracker object.
* \param fmt Format string.
* \return Number of bytes sent.
*/
extern int telnet_raw_printf(telnet_t *telnet, const char *fmt, ...)
TELNET_GNU_PRINTF(2, 3);
/*!
* \brief Send formatted data (no newline escaping).
*
* See telnet_raw_printf().
*/
extern int telnet_raw_vprintf(telnet_t *telnet, const char *fmt, va_list va);
/*!
* \brief Begin a new set of NEW-ENVIRON values to request or send.
*
* This function will begin the sub-negotiation block for sending or
* requesting NEW-ENVIRON values.
*
* The telnet_finish_newenviron() macro must be called after this
* function to terminate the NEW-ENVIRON command.
*
* \param telnet Telnet state tracker object.
* \param type One of TELNET_ENVIRON_SEND, TELNET_ENVIRON_IS, or
* TELNET_ENVIRON_INFO.
*/
extern void telnet_begin_newenviron(telnet_t *telnet, unsigned char type);
/*!
* \brief Send a NEW-ENVIRON variable name or value.
*
* This can only be called between calls to telnet_begin_newenviron() and
* telnet_finish_newenviron().
*
* \param telnet Telnet state tracker object.
* \param type One of TELNET_ENVIRON_VAR, TELNET_ENVIRON_USERVAR, or
* TELNET_ENVIRON_VALUE.
* \param string Variable name or value.
*/
extern void telnet_newenviron_value(telnet_t* telnet, unsigned char type,
const char *string);
/*!
* \brief Finish a NEW-ENVIRON command.
*
* This must be called after a call to telnet_begin_newenviron() to finish a
* NEW-ENVIRON variable list.
*
* \param telnet Telnet state tracker object.
*/
#define telnet_finish_newenviron(telnet) telnet_finish_sb((telnet))
/*!
* \brief Send the TERMINAL-TYPE SEND command.
*
* Sends the sequence IAC TERMINAL-TYPE SEND.
*
* \param telnet Telnet state tracker object.
*/
extern void telnet_ttype_send(telnet_t *telnet);
/*!
* \brief Send the TERMINAL-TYPE IS command.
*
* Sends the sequence IAC TERMINAL-TYPE IS "string".
*
* According to the RFC, the recipient of a TERMINAL-TYPE SEND shall
* send the next possible terminal-type the client supports. Upon sending
* the type, the client should switch modes to begin acting as the terminal
* type is just sent.
*
* The server may continue sending TERMINAL-TYPE IS until it receives a
* terminal type is understands. To indicate to the server that it has
* reached the end of the available optoins, the client must send the last
* terminal type a second time. When the server receives the same terminal
* type twice in a row, it knows it has seen all available terminal types.
*
* After the last terminal type is sent, if the client receives another
* TERMINAL-TYPE SEND command, it must begin enumerating the available
* terminal types from the very beginning. This allows the server to
* scan the available types for a preferred terminal type and, if none
* is found, to then ask the client to switch to an acceptable
* alternative.
*
* Note that if the client only supports a single terminal type, then
* simply sending that one type in response to every SEND will satisfy
* the behavior requirements.
*
* \param telnet Telnet state tracker object.
* \param ttype Name of the terminal-type being sent.
*/
extern void telnet_ttype_is(telnet_t *telnet, const char* ttype);
/*!
* \brief Send a ZMP command.
*
* \param telnet Telnet state tracker object.
* \param argc Number of ZMP commands being sent.
* \param argv Array of argument strings.
*/
extern void telnet_send_zmp(telnet_t *telnet, size_t argc, const char **argv);
/*!
* \brief Send a ZMP command.
*
* Arguments are listed out in var-args style. After the last argument, a
* NULL pointer must be passed in as a sentinel value.
*
* \param telnet Telnet state tracker object.
*/
extern void telnet_send_zmpv(telnet_t *telnet, ...) TELNET_GNU_SENTINEL;
/*!
* \brief Send a ZMP command.
*
* See telnet_send_zmpv().
*/
extern void telnet_send_vzmpv(telnet_t *telnet, va_list va);
/*!
* \brief Begin sending a ZMP command
*
* \param telnet Telnet state tracker object.
* \param cmd The first argument (command name) for the ZMP command.
*/
extern void telnet_begin_zmp(telnet_t *telnet, const char *cmd);
/*!
* \brief Send a ZMP command argument.
*
* \param telnet Telnet state tracker object.
* \param arg Telnet argument string.
*/
extern void telnet_zmp_arg(telnet_t *telnet, const char *arg);
/*!
* \brief Finish a ZMP command.
*
* This must be called after a call to telnet_begin_zmp() to finish a
* ZMP argument list.
*
* \param telnet Telnet state tracker object.
*/
#define telnet_finish_zmp(telnet) telnet_finish_sb((telnet))
/* C++ support */
#if defined(__cplusplus)
} /* extern "C" */
#endif
#endif /* !defined(LIBTELNET_INCLUDE) */
managed_components/frozen-eye__esp_telnet/src/server.c
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#include "freertos/FreeRTOS.h"
#include "sdkconfig.h"
#define LINEBUFFER_SIZE 256
#define AWAIT_TIMEOUT 10
#include <esp_log.h>
#include <libtelnet.h>
#include <lwip/def.h>
#include <lwip/sockets.h>
#include <telnet/server.h>
static const char* TAG = "telnet";
static struct user_t users[CONFIG_TELNET_SERVER_MAX_CONNECTIONS + 1];
static void linebuffer_push(char* buffer, size_t size, int* linepos, char ch,
void (*cb)(const char* line, size_t overflow, void* ud), void* ud)
{
/* CRLF -- line terminator */
if (ch == '\n' && *linepos > 0 && buffer[*linepos - 1] == '\r') {
/* NUL terminate (replaces \r in buffer), notify app, clear */
buffer[*linepos - 1] = 0;
cb(buffer, 0, ud);
*linepos = 0;
/* CRNUL -- just a CR */
}
else if (ch == 0 && *linepos > 0 && buffer[*linepos - 1] == '\r') {
/* do nothing, the CR is already in the buffer */
/* anything else (including technically invalid CR followed by
* anything besides LF or NUL -- just buffer if we have room
* \r
*/
}
else if (*linepos != (int)size) {
buffer[(*linepos)++] = ch;
/* buffer overflow */
}
else {
/* terminate (NOTE: eats a byte), notify app, clear buffer */
buffer[size - 1] = 0;
cb(buffer, size - 1, ud);
*linepos = 0;
}
}
static void _message(const char* from, const char* msg)
{
int i;
for (i = 0; i != CONFIG_TELNET_SERVER_MAX_CONNECTIONS; ++i) {
if (users[i].sock != -1 && users[i].name != 0 && strcmp(users[i].name, from) != 0) {
telnet_printf(users[i].telnet, "%s: \"%s\"\n", from, msg);
}
}
}
static void _broadcast(const char* from, const char* msg)
{
int i;
for (i = 0; i != CONFIG_TELNET_SERVER_MAX_CONNECTIONS; ++i) {
if (users[i].sock != -1) {
telnet_printf(users[i].telnet, "%s: \"%s\"\n", from, msg);
}
}
}
static void _send(int sock, const char* buffer, size_t size)
{
int rs;
/* ignore on invalid socket */
if (sock == -1)
return;
/* send data */
while (size > 0) {
if ((rs = send(sock, buffer, (int)size, 0)) == -1) {
if (errno != EINTR && errno != ECONNRESET) {
ESP_LOGW(TAG, "send() failed: %s", strerror(errno));
return;
}
else {
return;
}
}
else if (rs == 0) {
ESP_LOGE(TAG, "send() unexpectedly returned 0");
return;
}
/* update pointer and size to see if we've got more to send */
buffer += rs;
size -= rs;
}
}
/* process input line */
static void _online(const char* line, size_t overflow, void* ud)
{
struct user_t* user = (struct user_t*)ud;
int i;
(void)overflow;
/* if the user has no name, this is his "login" */
if (user->name == 0) {
/* must not be empty, must be at least 32 chars */
if (strlen(line) == 0 || strlen(line) > 32) {
telnet_printf(user->telnet, "Invalid name. Enter name: ");
return;
}
/* must not already exist */
for (i = 0; i != CONFIG_TELNET_SERVER_MAX_CONNECTIONS; ++i) {
if (users[i].name != 0 && strcmp(users[i].name, line) == 0) {
telnet_printf(user->telnet, "Name already in use. Enter name: ");
return;
}
}
/* keep name */
user->name = strdup(line);
telnet_printf(user->telnet, "Welcome, %s!\n", line);
return;
}
/* execute a command, need to send to the system */
// _message(user->name, line);
}
static void _input(struct user_t* user, const char* buffer, size_t size)
{
unsigned int i;
for (i = 0; user->sock != -1 && i != size; ++i) {
linebuffer_push(user->linebuf, sizeof(user->linebuf), &user->linepos, (char)buffer[i], _online, user);
}
}
static void _event_handler(telnet_t* telnet, telnet_event_t* ev, void* user_data)
{
struct user_t* user = (struct user_t*)user_data;
switch (ev->type) {
/* data received */
case TELNET_EV_DATA:
_input(user, ev->data.buffer, ev->data.size);
// telnet_negotiate(telnet, TELNET_WONT, TELNET_TELOPT_ECHO);
// telnet_negotiate(telnet, TELNET_WILL, TELNET_TELOPT_ECHO);
break;
/* data must be sent */
case TELNET_EV_SEND: _send(user->sock, ev->data.buffer, ev->data.size); break;
/* enable compress2 if accepted by client */
case TELNET_EV_DO:
if (ev->neg.telopt == TELNET_TELOPT_COMPRESS2)
telnet_begin_compress2(telnet);
break;
/* error */
case TELNET_EV_ERROR:
close(user->sock);
user->sock = -1;
if (user->name != 0) {
_message(user->name, "** HAS HAD AN ERROR **");
free(user->name);
user->name = 0;
}
telnet_free(user->telnet);
break;
default:
/* ignore */
break;
}
}
void telnet_task(void* arg)
{
static char buffer[512];
static struct sockaddr_in addr;
static telnet_server_config_t config;
// save the configuration
memcpy(&config, arg, sizeof(telnet_server_config_t));
int listen_sock;
int client_sock;
int rs;
int i;
socklen_t addrlen;
struct pollfd pfd[config.max_connections + 1];
/* initialize data structures */
memset(&pfd, 0, sizeof(pfd));
memset(users, 0, sizeof(users));
for (i = 0; i != config.max_connections; ++i) {
users[i].sock = -1;
}
/* create listening socket */
if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
ESP_LOGE(TAG, "socket() failed: %s", strerror(errno));
return;
}
/* reuse address option */
rs = 1;
setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (char*)&rs, sizeof(rs));
/* bind to listening addr/port */
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(config.port);
if (bind(listen_sock, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
ESP_LOGE(TAG, "bind() failed: %s", strerror(errno));
close(listen_sock);
return;
}
/* listen for clients */
if (listen(listen_sock, 3) == -1) {
ESP_LOGE(TAG, "listen() failed: %s", strerror(errno));
close(listen_sock);
return;
}
ESP_LOGI(TAG, "Telnet server listening on port %d", config.port);
/* initialize listening descriptors */
pfd[config.max_connections].fd = listen_sock;
pfd[config.max_connections].events = POLLIN;
/* loop for ever */
while (true) {
/* prepare for poll */
for (i = 0; i != config.max_connections; ++i) {
if (users[i].sock != -1) {
pfd[i].fd = users[i].sock;
pfd[i].events = POLLIN;
}
else {
pfd[i].fd = -1;
pfd[i].events = 0;
}
}
/* poll */
rs = poll(pfd, config.max_connections + 1, AWAIT_TIMEOUT);
if (rs == -1 && errno != EINTR) {
ESP_LOGE(TAG, "poll() failed: %s", strerror(errno));
close(listen_sock);
return;
}
/* new connection */
if (pfd[config.max_connections].revents & (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI | POLLERR | POLLHUP)) {
/* acept the sock */
ESP_LOGW(TAG, "New connection");
addrlen = sizeof(addr);
if ((client_sock = accept(listen_sock, (struct sockaddr*)&addr, &addrlen)) == -1) {
ESP_LOGE(TAG, "accept() failed: %s", strerror(errno));
return;
}
ESP_LOGV(TAG, "Connection received");
/* find a free user */
for (i = 0; i != config.max_connections; ++i) {
if (users[i].sock == -1) {
break;
}
}
if (i == config.max_connections) {
ESP_LOGV(TAG, " rejected (too many users)");
_send(client_sock, "Too many users.\n", 16);
close(client_sock);
}
/* init, welcome */
users[i].sock = client_sock;
users[i].telnet = telnet_init(config.telnet_opts, _event_handler, 0, &users[i]);
telnet_negotiate(users[i].telnet, TELNET_WILL, TELNET_TELOPT_COMPRESS2);
telnet_printf(users[i].telnet, "Enter name: ");
// telnet_negotiate(users[i].telnet, TELNET_WILL, TELNET_TELOPT_ECHO);
}
/* read from client */
for (i = 0; i != config.max_connections; ++i) {
/* skip users that aren't actually connected */
if (users[i].sock == -1) {
continue;
}
if (pfd[i].revents & (POLLIN | POLLERR | POLLHUP)) {
if ((rs = recv(users[i].sock, buffer, sizeof(buffer), 0)) > 0) {
telnet_recv(users[i].telnet, buffer, rs);
}
else if (rs == 0) {
ESP_LOGV(TAG, "Connection closed.");
close(users[i].sock);
users[i].sock = -1;
if (users[i].name != 0) {
// _message(users[i].name, "** HAS DISCONNECTED **");
free(users[i].name);
users[i].name = 0;
}
telnet_free(users[i].telnet);
}
else if (errno != EINTR) {
ESP_LOGE(TAG, "recv(client) failed: %s", strerror(errno));
return;
}
}
}
}
}
static TaskHandle_t xHandle = NULL;
esp_err_t telnet_server_create(telnet_server_config_t* config)
{
if (config == NULL) {
return ESP_ERR_INVALID_ARG;
}
BaseType_t xReturned = xTaskCreate(telnet_task, "telnet_task", config->stack_size, config, config->task_priority, &xHandle);
if (xReturned == pdPASS) {
ESP_LOGV(TAG, "Telnet task created successfully.");
return ESP_OK;
}
ESP_LOGE(TAG, "Failed to create telnet task.");
return ESP_FAIL;
}