vss.c File Reference

Macros
#define	MAP_POPULATE   0

Enumerations
enum	afs_socket_status { AFS_SOCKET_READY, AFS_SOCKET_CHECK_FOR_WRITE, AFS_SOCKET_AFD_PENDING }
enum	fec_client_state { FEC_STATE_NONE = 0, FEC_STATE_DISABLED, FEC_STATE_READY_TO_RUN }

Functions
size_t	vss_get_fec_eof_packet (const char **buf)
struct fec_client *	vss_add_fec_client (struct sender_client *sc, struct fec_client_parms *fcp)
void	vss_del_fec_client (struct fec_client *fc)
bool	vss_playing (void)
bool	vss_paused (void)
bool	vss_stopped (void)
void	vss_init (int afs_socket, struct sched *s)
void	vss_shutdown (void)

Variables
struct misc_meta_data *	mmd
const struct sender udp_sender dccp_sender	http_sender
const struct sender *const	senders []

Detailed Description

The virtual streaming system.

This contains the audio streaming code of para_server which is independent of the current audio format, audio file selector and of the activated senders.

Macro Definition Documentation

MAP_POPULATE

#define MAP_POPULATE   0

As of 2018, neither FreeBSD-11.2 nor NetBSD-8.0 have MAP_POPULATE.

Enumeration Type Documentation

afs_socket_status

enum afs_socket_status

The possible states of the afs socket.

Enumerator
AFS_SOCKET_READY	Socket is inactive.
AFS_SOCKET_CHECK_FOR_WRITE	Socket fd was monitored for writing.
AFS_SOCKET_AFD_PENDING	vss wrote a request to the socket and waits for reply from afs.

fec_client_state

enum fec_client_state

A FEC client is always in one of these states.

Enumerator
FEC_STATE_NONE	not initialized and not enabled
FEC_STATE_DISABLED	temporarily disabled
FEC_STATE_READY_TO_RUN	initialized and enabled

Function Documentation

vss_get_fec_eof_packet()

size_t vss_get_fec_eof_packet

(

const char **

buf

)

Return a buffer that marks the end of the stream.

Parameters

buf	Result pointer.

Returns

The length of the eof buffer.

This is used for (multicast) udp streaming where closing the socket on the sender might not give rise to an eof condition at the peer.

References FEC_EOF_PACKET, and FEC_HEADER_SIZE.

vss_add_fec_client()

struct fec_client* vss_add_fec_client	(	struct sender_client *	sc,
		struct fec_client_parms *	fcp
	)

Add one entry to the list of active fec clients.

Parameters

sc	Generic sender_client data of the transport layer.
fcp	FEC parameters as supplied by the transport layer.

Returns

Newly allocated fec_client struct.

References zalloc().

vss_del_fec_client()

void vss_del_fec_client

(

struct fec_client *

fc

)

Remove one entry from the list of active fec clients.

Parameters

fc	The client to be removed.

vss_playing()

bool vss_playing

(

void

)

Check if the "P" (playing) vss status flag is set.

Returns

True if playing, false otherwise.

References mmd, misc_meta_data::new_vss_status_flags, and VSS_PLAYING.

vss_paused()

bool vss_paused

(

void

)

Check if the virtual streaming system is currently paused.

Returns

True if paused, false otherwise.

References mmd, misc_meta_data::new_vss_status_flags, VSS_NEXT, and VSS_PLAYING.

vss_stopped()

bool vss_stopped

(

void

)

Check if the virtual streaming system is currently stopped.

Returns

True iff stopped.

References mmd, misc_meta_data::new_vss_status_flags, VSS_NEXT, and VSS_PLAYING.

vss_init()

void vss_init	(	int	afs_socket,
		struct sched *	s
	)

Initialize the virtual streaming system task.

Parameters

afs_socket	The fd for communication with afs.
s	The scheduler to register the vss task to.

This also initializes all supported senders and starts streaming if the –autoplay command line flag was given.

References ms2tv(), OPT_UINT32_VAL, PARA_DEBUG_LOG, and tv2ms().

vss_shutdown()

void vss_shutdown

(

void

)

Turn off the virtual streaming system.

This is only executed on exit. It calls the ->shutdown method of all senders.

References FOR_EACH_SENDER, PARA_NOTICE_LOG, process_is_command_handler(), senders, and sender::shutdown.

Variable Documentation

mmd

struct misc_meta_data* mmd

extern

Pointer to shared memory area for communication between para_server and its children.

Exported to vss.c, command.c and to afs.

Referenced by vss_paused(), vss_playing(), and vss_stopped().

http_sender

const struct sender udp_sender dccp_sender http_sender

extern

The HTTP sender.

This is the only sender which does not FEC-encode the stream. This is not necessary because HTTP sits on top of TCP, a reliable transport which retransmits lost packets automatically. The sender employs per-client queues which queue chunks of audio data if they can not be sent immediately because the write operation would block. Most methods of the sender are implemented as wrappers for the generic functions defined in send_common.c.

senders

const struct sender* const senders[]

Initial value:

= {
        &http_sender, &dccp_sender, &udp_sender, NULL}

NULL-terminated list, defined in vss.c.

Referenced by vss_shutdown().