TURN

TURN — TURN Allocation Usage

Stability Level

Stable, unless otherwise indicated

Synopsis

#include <stun/usages/turn.h>

enum                StunUsageTurnCompatibility;
enum                StunUsageTurnRequestPorts;
enum                StunUsageTurnReturn;
size_t              stun_usage_turn_create              (StunAgent *agent,
                                                         StunMessage *msg,
                                                         uint8_t *buffer,
                                                         size_t buffer_len,
                                                         StunMessage *previous_response,
                                                         StunUsageTurnRequestPorts request_ports,
                                                         int32_t bandwidth,
                                                         int32_t lifetime,
                                                         uint8_t *username,
                                                         size_t username_len,
                                                         uint8_t *password,
                                                         size_t password_len,
                                                         StunUsageTurnCompatibility compatibility);
size_t              stun_usage_turn_create_refresh      (StunAgent *agent,
                                                         StunMessage *msg,
                                                         uint8_t *buffer,
                                                         size_t buffer_len,
                                                         StunMessage *previous_response,
                                                         int32_t lifetime,
                                                         uint8_t *username,
                                                         size_t username_len,
                                                         uint8_t *password,
                                                         size_t password_len,
                                                         StunUsageTurnCompatibility compatibility);
StunUsageTurnReturn  stun_usage_turn_process            (StunMessage *msg,
                                                         struct sockaddr *relay_addr,
                                                         socklen_t *relay_addrlen,
                                                         struct sockaddr *addr,
                                                         socklen_t *addrlen,
                                                         struct sockaddr *alternate_server,
                                                         socklen_t *alternate_server_len,
                                                         uint32_t *bandwidth,
                                                         uint32_t *lifetime,
                                                         StunUsageTurnCompatibility compatibility);
StunUsageTurnReturn  stun_usage_turn_refresh_process    (StunMessage *msg,
                                                         uint32_t *lifetime,
                                                         StunUsageTurnCompatibility compatibility);

Description

The STUN TURN usage allows for easily creating and parsing STUN Allocate requests and responses used for TURN. The API allows you to create a new allocation or refresh an existing one as well as to parse a response to an allocate or refresh request.

Details

enum StunUsageTurnCompatibility

typedef enum {
  STUN_USAGE_TURN_COMPATIBILITY_DRAFT9,
  STUN_USAGE_TURN_COMPATIBILITY_GOOGLE,
  STUN_USAGE_TURN_COMPATIBILITY_MSN,
} StunUsageTurnCompatibility;

Specifies which TURN specification compatibility to use

STUN_USAGE_TURN_COMPATIBILITY_DRAFT9

Use the specification compatible with TURN Draft 09

STUN_USAGE_TURN_COMPATIBILITY_GOOGLE

Use the specification compatible with Google Talk's relay server

STUN_USAGE_TURN_COMPATIBILITY_MSN

Use the specification compatible with MSN TURN servers

enum StunUsageTurnRequestPorts

typedef enum {
  STUN_USAGE_TURN_REQUEST_PORT_NORMAL = 0,
  STUN_USAGE_TURN_REQUEST_PORT_EVEN = 1,
  STUN_USAGE_TURN_REQUEST_PORT_EVEN_AND_RESERVE = 2
} StunUsageTurnRequestPorts;

This enum is used to specify which port configuration you want when creating a new Allocation

STUN_USAGE_TURN_REQUEST_PORT_NORMAL

Request a normal port

STUN_USAGE_TURN_REQUEST_PORT_EVEN

Request an even port

STUN_USAGE_TURN_REQUEST_PORT_EVEN_AND_RESERVE

Request an even port and reserve the next higher port

enum StunUsageTurnReturn

typedef enum {
  STUN_USAGE_TURN_RETURN_RELAY_SUCCESS,
  STUN_USAGE_TURN_RETURN_MAPPED_SUCCESS,
  STUN_USAGE_TURN_RETURN_ERROR,
  STUN_USAGE_TURN_RETURN_INVALID,
  STUN_USAGE_TURN_RETURN_ALTERNATE_SERVER,
} StunUsageTurnReturn;

Return value of stun_usage_turn_process() and stun_usage_turn_refresh_process() which allows you to see what status the function call returned.

STUN_USAGE_TURN_RETURN_RELAY_SUCCESS

The response was successful and a relay address is provided

STUN_USAGE_TURN_RETURN_MAPPED_SUCCESS

The response was successful and a relay address as well as a mapped address are provided

STUN_USAGE_TURN_RETURN_ERROR

The response resulted in an error

STUN_USAGE_TURN_RETURN_INVALID

The response is not a valid response

STUN_USAGE_TURN_RETURN_ALTERNATE_SERVER

The server requests the message to be sent to an alternate server

stun_usage_turn_create ()

size_t              stun_usage_turn_create              (StunAgent *agent,
                                                         StunMessage *msg,
                                                         uint8_t *buffer,
                                                         size_t buffer_len,
                                                         StunMessage *previous_response,
                                                         StunUsageTurnRequestPorts request_ports,
                                                         int32_t bandwidth,
                                                         int32_t lifetime,
                                                         uint8_t *username,
                                                         size_t username_len,
                                                         uint8_t *password,
                                                         size_t password_len,
                                                         StunUsageTurnCompatibility compatibility);

Create a new TURN Allocation request

agent :

The StunAgent to use to build the request

msg :

The StunMessage to build

buffer :

The buffer to use for creating the StunMessage

buffer_len :

The size of the buffer

previous_response :

If this is the first request you are sending, set this argument to NULL, if it's a subsequent request you are building, then set this argument to the response you have received. This argument is used for building long term credentials (using the REALM and NONCE attributes) as well as for getting the RESERVATION-TOKEN attribute when you previously requested an allocation which reserved two ports

request_ports :

Specify how you want to request the allocated port(s). This is only used if the compatibility is set to STUN_USAGE_TURN_COMPATIBILITY_DRAFT9

See StunUsageTurnRequestPorts

bandwidth :

The bandwidth to request from the server for the allocation. If this value is negative, then no BANDWIDTH attribute is added to the request. This is only used if the compatibility is set to STUN_USAGE_TURN_COMPATIBILITY_DRAFT9

lifetime :

The lifetime of the allocation to request from the server. If this value is negative, then no LIFETIME attribute is added to the request. This is only used if the compatibility is set to STUN_USAGE_TURN_COMPATIBILITY_DRAFT9

username :

The username to use in the request

username_len :

The length of username

password :

The key to use for building the MESSAGE-INTEGRITY

password_len :

The length of password

compatibility :

The compatibility mode to use for building the Allocation request

Returns :

The length of the message to send

stun_usage_turn_create_refresh ()

size_t              stun_usage_turn_create_refresh      (StunAgent *agent,
                                                         StunMessage *msg,
                                                         uint8_t *buffer,
                                                         size_t buffer_len,
                                                         StunMessage *previous_response,
                                                         int32_t lifetime,
                                                         uint8_t *username,
                                                         size_t username_len,
                                                         uint8_t *password,
                                                         size_t password_len,
                                                         StunUsageTurnCompatibility compatibility);

Create a new TURN Refresh request

agent :

The StunAgent to use to build the request

msg :

The StunMessage to build

buffer :

The buffer to use for creating the StunMessage

buffer_len :

The size of the buffer

previous_response :

If this is the first request you are sending, set this argument to NULL, if it's a subsequent request you are building, then set this argument to the response you have received. This argument is used for building long term credentials (using the REALM and NONCE attributes)

lifetime :

The lifetime of the allocation to request from the server. If this value is negative, then no LIFETIME attribute is added to the request. This is only used if the compatibility is set to STUN_USAGE_TURN_COMPATIBILITY_DRAFT9

username :

The username to use in the request

username_len :

The length of username

password :

The key to use for building the MESSAGE-INTEGRITY

password_len :

The length of password

compatibility :

The compatibility mode to use for building the Allocation request

Returns :

The length of the message to send

stun_usage_turn_process ()

StunUsageTurnReturn  stun_usage_turn_process            (StunMessage *msg,
                                                         struct sockaddr *relay_addr,
                                                         socklen_t *relay_addrlen,
                                                         struct sockaddr *addr,
                                                         socklen_t *addrlen,
                                                         struct sockaddr *alternate_server,
                                                         socklen_t *alternate_server_len,
                                                         uint32_t *bandwidth,
                                                         uint32_t *lifetime,
                                                         StunUsageTurnCompatibility compatibility);

Process a TURN Allocate response and extract the necessary information from the message

msg :

The message containing the response

relay_addr :

A pointer to a sockaddr structure to fill with the relay address that the TURN server allocated for us

relay_addrlen :

The length of relay_addr

addr :

A pointer to a sockaddr structure to fill with the mapped address that the STUN response contains. This argument will only be filled if the return value of the function is STUN_USAGE_TURN_RETURN_MAPPED_SUCCESS

addrlen :

The length of addr

alternate_server :

A pointer to a sockaddr structure to fill with the address of an alternate server to which we should send our new STUN Allocate request, in case the currently used TURN server is requesting the use of an alternate server. This argument will only be filled if the return value of the function is STUN_USAGE_TURN_RETURN_ALTERNATE_SERVER

alternate_server_len :

The length of alternate_server

bandwidth :

A pointer to fill with the bandwidth the TURN server allocated us

lifetime :

A pointer to fill with the lifetime of the allocation

compatibility :

The compatibility mode to use for processing the Allocation response

Returns :

A StunUsageTurnReturn value

stun_usage_turn_refresh_process ()

StunUsageTurnReturn  stun_usage_turn_refresh_process    (StunMessage *msg,
                                                         uint32_t *lifetime,
                                                         StunUsageTurnCompatibility compatibility);

Process a TURN Refresh response and extract the necessary information from the message

msg :

The message containing the response

lifetime :

A pointer to fill with the lifetime of the allocation

compatibility :

The compatibility mode to use for processing the Refresh response

Returns :

A StunUsageTurnReturn value. A STUN_USAGE_TURN_RETURN_RELAY_SUCCESS means the Refresh was successful, but no relay address is given (kept the same as for the original allocation)