Group PJNATH_STUN_SOCK

group PJNATH_STUN_SOCK

STUN aware UDP socket transport.

The STUN transport provides asynchronous UDP like socket transport with the additional STUN capability. It has the following features:

API to send and receive UDP packets
multiplex STUN and non-STUN incoming packets and distinguish between STUN responses that belong to internal requests with application data (the application data may be STUN packets as well)
DNS SRV resolution to the STUN server (if wanted), along with fallback to DNS A resolution if SRV record is not found.
STUN keep-alive maintenance, and handle changes to the mapped address (when the NAT binding changes)

Typedefs

typedef struct pj_stun_sock pj_stun_sock: Opaque type to represent a STUN transport.

Enums

enum pj_stun_sock_op

Types of operation being reported in on_status() callback of pj_stun_sock_cb. Application may retrieve the string representation of these constants with pj_stun_sock_op_name().

Values:

enumerator PJ_STUN_SOCK_DNS_OP: Asynchronous DNS resolution.

enumerator PJ_STUN_SOCK_BINDING_OP: Initial STUN Binding request.

enumerator PJ_STUN_SOCK_KEEP_ALIVE_OP: Subsequent STUN Binding request for keeping the binding alive.

enumerator PJ_STUN_SOCK_MAPPED_ADDR_CHANGE: IP address change notification from the keep-alive operation.

Functions

const char *pj_stun_sock_op_name(pj_stun_sock_op op): Retrieve the name representing the specified operation.

void pj_stun_sock_cfg_default(pj_stun_sock_cfg *cfg)

Initialize the STUN transport setting with its default values.

Parameters:: cfg – The STUN transport config.

pj_status_t pj_stun_sock_create(pj_stun_config *stun_cfg, const char *name, int af, const pj_stun_sock_cb *cb, const pj_stun_sock_cfg *cfg, void *user_data, pj_stun_sock **p_sock)

Create the STUN transport using the specified configuration. Once the STUN transport has been create, application should call pj_stun_sock_start() to start the transport.

Parameters:

stun_cfg – The STUN configuration which contains among other things the ioqueue and timer heap instance for the operation of this transport.
af – Address family of socket. Currently pj_AF_INET() and pj_AF_INET6() are supported.
name – Optional name to be given to this transport to assist debugging.
cb – Callback to receive events/data from the transport.
cfg – Optional transport settings.
user_data – Arbitrary application data to be associated with this transport.
p_sock – Pointer to receive the created transport instance.

Returns:

PJ_SUCCESS if the operation has been successful, or the appropriate error code on failure.

pj_status_t pj_stun_sock_start(pj_stun_sock *stun_sock, const pj_str_t *domain, pj_uint16_t default_port, pj_dns_resolver *resolver)

Start the STUN transport. This will start the DNS SRV resolution for the STUN server (if desired), and once the server is resolved, STUN Binding request will be sent to resolve the publicly mapped address. Once the initial STUN Binding response is received, the keep-alive timer will be started.

Parameters:

stun_sock – The STUN transport instance.
domain – The domain, hostname, or IP address of the STUN server. When this parameter contains domain name, the resolver parameter must be set to activate DNS SRV resolution.
default_port – The default STUN port number to use when DNS SRV resolution is not used. If DNS SRV resolution is used, the server port number will be set from the DNS SRV records. The recommended value for this parameter is PJ_STUN_PORT.
resolver – If this parameter is not NULL, then the domain parameter will be first resolved with DNS SRV and then fallback to using DNS A/AAAA resolution when DNS SRV resolution fails. If this parameter is NULL, the domain parameter will be resolved as hostname.

Returns:

PJ_SUCCESS if the operation has been successfully queued, or the appropriate error code on failure. When this function returns PJ_SUCCESS, the final result of the allocation process will be notified to application in on_status() callback.

pj_status_t pj_stun_sock_destroy(pj_stun_sock *sock)

Destroy the STUN transport.

Parameters:: sock – The STUN transport socket.
Returns:: PJ_SUCCESS if the operation has been successful, or the appropriate error code on failure.

pj_status_t pj_stun_sock_set_user_data(pj_stun_sock *stun_sock, void *user_data)

Associate a user data with this STUN transport. The user data may then be retrieved later with pj_stun_sock_get_user_data().

Parameters:

stun_sock – The STUN transport instance.
user_data – Arbitrary data.

Returns:

PJ_SUCCESS if the operation has been successful, or the appropriate error code on failure.

void *pj_stun_sock_get_user_data(pj_stun_sock *stun_sock)

Retrieve the previously assigned user data associated with this STUN transport.

Parameters:: stun_sock – The STUN transport instance.
Returns:: The user/application data.

pj_grp_lock_t *pj_stun_sock_get_grp_lock(pj_stun_sock *stun_sock)

Get the group lock for this STUN transport.

Parameters:: stun_sock – The STUN transport instance.
Returns:: The group lock.

pj_status_t pj_stun_sock_get_info(pj_stun_sock *stun_sock, pj_stun_sock_info *info)

Get the STUN transport info. The transport info contains, among other things, the allocated relay address.

Parameters:

stun_sock – The STUN transport instance.
info – Pointer to be filled with STUN transport info.

Returns:

PJ_SUCCESS if the operation has been successful, or the appropriate error code on failure.

pj_status_t pj_stun_sock_sendto(pj_stun_sock *stun_sock, pj_ioqueue_op_key_t *send_key, const void *pkt, unsigned pkt_len, unsigned flag, const pj_sockaddr_t *dst_addr, unsigned addr_len)

Send a data to the specified address. This function may complete asynchronously and in this case on_data_sent() will be called.

Parameters:

stun_sock – The STUN transport instance.
send_key – Optional send key for sending the packet down to the ioqueue. This value will be given back to on_data_sent() callback
pkt – The data/packet to be sent to peer.
pkt_len – Length of the data.
flag – pj_ioqueue_sendto() flag.
dst_addr – The remote address.
addr_len – Length of the address.

Returns:

PJ_SUCCESS if data has been sent immediately, or PJ_EPENDING if data cannot be sent immediately. In this case the on_data_sent() callback will be called when data is actually sent. Any other return value indicates error condition.

struct pj_stun_sock_cb

#include <stun_sock.h>

This structure contains callbacks that will be called by the STUN transport to notify application about various events.

Public Members

pj_bool_t (*on_rx_data)(pj_stun_sock *stun_sock, void *pkt, unsigned pkt_len, const pj_sockaddr_t *src_addr, unsigned addr_len)

Notification when incoming packet has been received.

Param stun_sock:: The STUN transport.
Param data:: The packet.
Param data_len:: Length of the packet.
Param src_addr:: The source address of the packet.
Param addr_len:: The length of the source address.
Return:: Application should normally return PJ_TRUE to let the STUN transport continue its operation. However it must return PJ_FALSE if it has destroyed the STUN transport in this callback.

pj_bool_t (*on_data_sent)(pj_stun_sock *stun_sock, pj_ioqueue_op_key_t *send_key, pj_ssize_t sent)

Notifification when asynchronous send operation has completed.

Param stun_sock:: The STUN transport.
Param send_key:: The send operation key that was given in pj_stun_sock_sendto().
Param sent:: If value is positive non-zero it indicates the number of data sent. When the value is negative, it contains the error code which can be retrieved by negating the value (i.e. status=-sent).
Return:: Application should normally return PJ_TRUE to let the STUN transport continue its operation. However it must return PJ_FALSE if it has destroyed the STUN transport in this callback.

pj_bool_t (*on_status)(pj_stun_sock *stun_sock, pj_stun_sock_op op, pj_status_t status)

Notification when the status of the STUN transport has changed. This callback may be called for the following conditions:

the first time the publicly mapped address has been resolved from the STUN server, this callback will be called with op argument set to PJ_STUN_SOCK_BINDING_OP status argument set to PJ_SUCCESS.
anytime when the transport has detected that the publicly mapped address has changed, this callback will be called with op argument set to PJ_STUN_SOCK_KEEP_ALIVE_OP and status argument set to PJ_SUCCESS. On this case and the case above, application will get the resolved public address in the pj_stun_sock_info structure.
for any terminal error (such as STUN time-out, DNS resolution failure, or keep-alive failure), this callback will be called with the status argument set to non-PJ_SUCCESS.

Param stun_sock:: The STUN transport.
Param op:: The operation that triggers the callback.
Param status:: The status.
Return:: Must return PJ_FALSE if it has destroyed the STUN transport in this callback. Application should normally destroy the socket and return PJ_FALSE upon encountering terminal error, otherwise it should return PJ_TRUE to let the STUN socket operation continues.

struct pj_stun_sock_info

#include <stun_sock.h>

This structure contains information about the STUN transport. Application may query this information by calling pj_stun_sock_get_info().

Public Members

pj_sockaddr bound_addr: The bound address of the socket.

pj_sockaddr srv_addr: IP address of the STUN server.

pj_sockaddr mapped_addr: The publicly mapped address. It may contain zero address when the mapped address has not been resolved. Application may query whether this field contains valid address with pj_sockaddr_has_addr().

unsigned alias_cnt: Number of interface address aliases. The interface address aliases are list of all interface addresses in this host.

pj_sockaddr aliases[PJ_ICE_ST_MAX_CAND]: Array of interface address aliases.

struct pj_stun_sock_cfg

#include <stun_sock.h>

This describe the settings to be given to the STUN transport during its creation. Application should initialize this structure by calling pj_stun_sock_cfg_default().

Public Members

pj_grp_lock_t *grp_lock

The group lock to be used by the STUN socket. If NULL, the STUN socket will create one internally.

Default: NULL

unsigned max_pkt_size

Packet buffer size.

Default value is PJ_STUN_SOCK_PKT_LEN.

unsigned async_cnt: Specify the number of simultaneous asynchronous read operations to be invoked to the ioqueue. Having more than one read operations will increase performance on multiprocessor systems since the application will be able to process more than one incoming packets simultaneously. Default value is 1.

pj_sockaddr bound_addr: Specify the interface where the socket should be bound to. If the address is zero, socket will be bound to INADDR_ANY. If the address is non-zero, socket will be bound to this address only, and the transport will have only one address alias (the alias_cnt field in pj_stun_sock_info structure. If the port is set to zero, the socket will bind at any port (chosen by the OS).

pj_uint16_t port_range

Specify the port range for STUN socket binding, relative to the start port number specified in bound_addr. Note that this setting is only applicable when the start port number is non zero.

Default value is zero.

int ka_interval: Specify the STUN keep-alive duration, in seconds. The STUN transport does keep-alive by sending STUN Binding request to the STUN server. If this value is zero, the PJ_STUN_KEEP_ALIVE_SEC value will be used. If the value is negative, it will disable STUN keep-alive.

pj_qos_type qos_type

QoS traffic type to be set on this transport. When application wants to apply QoS tagging to the transport, it’s preferable to set this field rather than qos_param fields since this is more portable.

Default value is PJ_QOS_TYPE_BEST_EFFORT.

pj_qos_params qos_params

Set the low level QoS parameters to the transport. This is a lower level operation than setting the qos_type field and may not be supported on all platforms.

By default all settings in this structure are disabled.

pj_bool_t qos_ignore_error

Specify if STUN socket should ignore any errors when setting the QoS traffic type/parameters.

Default: PJ_TRUE

unsigned so_rcvbuf_size

Specify target value for socket receive buffer size. It will be applied using setsockopt(). When it fails to set the specified size, it will try with lower value until the highest possible is successfully set.

Default: 0 (OS default)

unsigned so_sndbuf_size

Specify target value for socket send buffer size. It will be applied using setsockopt(). When it fails to set the specified size, it will try with lower value until the highest possible is successfully set.

Default: 0 (OS default)