| /* |
| * 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. |
| */ |
| |
| /* sub request buffer size increment (defualt 4K) */ |
| #define LIBTELNET_BUFFER_SIZE (4 * 1024) |
| /* sub request buffer size (default 16K) */ |
| #define LIBTELNET_BUFFER_SIZE_MAX (16 * 1024) |
| |
| /* telnet special values */ |
| #define LIBTELNET_IAC 255 |
| #define LIBTELNET_DONT 254 |
| #define LIBTELNET_DO 253 |
| #define LIBTELNET_WONT 252 |
| #define LIBTELNET_WILL 251 |
| #define LIBTELNET_SB 250 |
| #define LIBTELNET_SE 240 |
| |
| /* telnet options */ |
| #define LIBTELNET_OPTION_BINARY 0 |
| #define LIBTELNET_OPTION_ECHO 1 |
| #define LIBTELNET_OPTION_NAWS 31 |
| #define LIBTELNET_OPTION_ZMP 93 |
| |
| /* telnet states */ |
| enum libtelnet_state_t { |
| LIBTELNET_STATE_TEXT = 0, |
| LIBTELNET_STATE_IAC, |
| LIBTELNET_STATE_DO, |
| LIBTELNET_STATE_DONT, |
| LIBTELNET_STATE_WILL, |
| LIBTELNET_STATE_WONT, |
| LIBTELNET_STATE_SB, |
| LIBTELNET_STATE_SB_IAC, |
| }; |
| |
| /* error codes */ |
| enum libtelnet_error_t { |
| LIBTELNET_ERROR_OK = 0, |
| LIBTELNET_ERROR_OVERFLOW, /* input exceeds buffer size */ |
| LIBTELNET_ERROR_PROTOCOL, /* invalid sequence of special bytes */ |
| LIBTELNET_ERROR_UNKNOWN, /* some crazy unexplainable unknown error */ |
| }; |
| |
| /* callback prototypes */ |
| typedef (void)(*libtelnet_input)(struct libtelnet_t *telnet, unsigned char |
| byte, void *user_data); |
| typedef (void)(*libtelnet_output)(struct libtelnet_t *telnet, unsigned char |
| byte, void *user_data); |
| typedef (void)(*libtelnet_command)(struct libtelnet_t *telnet, unsigned char |
| cmd, void *user_data); |
| typedef (void)(*libtelnet_negotiate)(struct libtelnet_t *telnet, unsigned char |
| cmd, unsigned char opt, void *user_data); |
| typedef (void)(*libtelnet_subrequest)(struct libtelnet_t *telnet, unsigned char |
| cmd, unsigned char type, unsigned char *data, size_t size, |
| void *user_data); |
| typedef (void)(*libtelnet_error)(struct libtelnet_t *telnet, |
| enum libtelnet_error_t error, void *user_data); |
| |
| /* state tracker */ |
| struct libtelnet_t { |
| /* current state */ |
| enum libtelnet_state_t state; |
| /* sub-request buffer */ |
| char *buffer; |
| /* current size of the buffer */ |
| size_t size; |
| /* length of data in the buffer */ |
| size_t length; |
| |
| /* callbacks */ |
| libtelnet_input input_cb; |
| libtelnet_output output_cb; |
| libtelnet_command command_cb; |
| libtelnet_negotiate negotiate_cb; |
| libtelnet_subrequest subrequest_cb; |
| }; |
| |
| /* initialize a telnet state tracker */ |
| void libtelnet_init(struct libtelnet_t *telnet); |
| |
| /* free up any memory allocated by a state tracker */ |
| void libtelnet_close(struct libtelnet_t *telnet); |
| |
| /* push a single byte into the state tracker */ |
| void libtelnet_push_byte(struct libtelnet_t *telnet, unsigned char byte, |
| void *user_data); |
| |
| /* push a byte buffer into the state tracker */ |
| void libtelnet_push_buffer(struct libtelnet_t *telnet, unsigned char *buffer, |
| size_t size, void *user_data); |
| |
| /* send an iac command */ |
| void libtelnet_send_command(struct libtelnet_t *telnet, unsigned char cmd, |
| void *user_data); |
| |
| /* send negotiation */ |
| void libtelnet_send_negotiate(struct libtelnet_t *telnet, unsigned char cmd, |
| unsigned char opt, void *user_data); |
| |
| /* send non-command data (escapes IAC bytes) */ |
| void libtelnet_send_data(struct libtelnet_t *telnet, unsigned char *buffer, |
| size_t size, void *user_data); |
| |
| /* send sub-request */ |
| void libtelnet_send_subrequest(struct libtelnet_t *telnet, unsigned char type, |
| unsigned char *buffer, size_t size, void *user_data); |