server.h File Reference

Data Structures
struct	sender_command_data
struct	misc_meta_data

Macros
#define	MMD_INFO_SIZE   16384
#define	OPT_RESULT(_name)
#define	OPT_GIVEN(_name)   (lls_opt_given(OPT_RESULT(_name)))
#define	OPT_STRING_VAL(_name)   (lls_string_val(0, OPT_RESULT(_name)))
#define	OPT_UINT32_VAL(_name)   (lls_uint32_val(0, OPT_RESULT(_name)))
#define	OPT_INT32_VAL(_name)   (lls_int32_val(0, OPT_RESULT(_name)))

Functions
int	handle_connect (int fd)
void	parse_config_or_die (bool reload)
bool	process_is_command_handler (void)
void	free_lpr (void)

Variables
pid_t	afs_pid
struct lls_parse_result *	server_lpr

Macro Definition Documentation

MMD_INFO_SIZE

#define MMD_INFO_SIZE   16384

Size of the selector_info and audio_file info strings of struct misc_meta_data.

OPT_RESULT

#define OPT_RESULT

(

_name

)

Value:

                (lls_opt_result( \
                LSG_SERVER_PARA_SERVER_OPT_ ## _name, server_lpr))

Get the parse result of an option to para_server.

OPT_GIVEN

#define OPT_GIVEN

(

_name

)

(lls_opt_given(OPT_RESULT(_name)))

How many times a server option was given.

OPT_STRING_VAL

#define OPT_STRING_VAL

(

_name

)

(lls_string_val(0, OPT_RESULT(_name)))

The (first) argument to a server option of type string.

OPT_UINT32_VAL

#define OPT_UINT32_VAL

(

_name

)

(lls_uint32_val(0, OPT_RESULT(_name)))

The (first) argument to a server option of type uint32.

OPT_INT32_VAL

#define OPT_INT32_VAL

(

_name

)

(lls_int32_val(0, OPT_RESULT(_name)))

The (first) argument to a server option of type int32.

Function Documentation

handle_connect()

int handle_connect

(

int

fd

)

Perform user authentication and execute a command.

Parameters

fd	The file descriptor to send output to.

Whenever para_server accepts an incoming tcp connection on the port it listens on, it forks and the resulting child calls this function.

An RSA-based challenge/response is used to authenticate the peer. If the authentication succeeds, a random session key is generated and sent back to the peer, encrypted with its RSA public key. From this point on, all transfers are encrypted with this session key using a stream cipher.

Next it is checked if the peer supplied a valid server command or a command for the audio file selector. If yes, and if the user has sufficient permissions to execute this command, the function calls the corresponding command handler which performs argument checking and further processing.

To cope with DOS attacks, a timer is set up right after the fork. If the connection was still not authenticated when the timeout expires, the child process is terminated.

Returns

Standard.

See also

alarm(2), openssl.c, crypt.h.

References APC_CHALLENGE_SIZE, stream_cipher_context::fd, HANDSHAKE_BUFSIZE, HASH2_SIZE, command_context::scc, SESSION_KEY_LEN, and command_context::u.

parse_config_or_die()

void parse_config_or_die

(

bool

reload

)

(Re-)read the server configuration files.

Parameters

reload

Whether config file overrides command line.

This function also re-opens the logfile and the user list. On SIGHUP it is called from both server and afs context.

References MCF_DONT_FREE, and server_lpr.

process_is_command_handler()

bool process_is_command_handler

(

void

)

Tell whether the executing process is a command handler.

Cleanup on exit must be performed differently for command handlers.

Returns

True if the pid of the executing process is neither the server pid nor the afs pid.

References afs_pid.

Referenced by shutdown_client(), and vss_shutdown().

free_lpr()

void free_lpr

(

void

)

Deallocate all lopsub parse results.

The server allocates a parse result for command line options and optionally a second parse result for the effective configuration, defined by merging the command line options with the options stored in the configuration file. This function frees both structures.

References CMD_PTR, and server_lpr.

Variable Documentation

afs_pid

pid_t afs_pid

extern

The process id of the audio file selector process.

Referenced by process_is_command_handler().

server_lpr

struct lls_parse_result* server_lpr

extern

The active value for all config options of para_server.

It is computed by merging the parse result of the command line options with the parse result of the config file.

Referenced by free_lpr(), and parse_config_or_die().