event.c File Reference

separate eventing thread to run libosmocore's event loop More...

#include <osmocom/core/talloc.h>
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/io/schedule.h>
#include <unistd.h>
#include <semaphore.h>
#include <signal.h>
#include <osmocom/core/logging.h>
#include <osmocom/sccp/sccp_types.h>
#include <osmocom/mtp/mtp_level3.h>
#include "libosmo-m3ua/include/bsc_data.h"
#include "libosmo-m3ua/include/sctp_m3ua.h"
#include "sigtran.h"

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Macros
#define	LOG_PREFIX   "sigtran"

Typedefs
typedef int(*	osmo_cb_func) (struct osmo_fd *fd, unsigned int what)

Functions
static int	_mtp3_link_free (struct mtp_link *mtp3_link)
	Shutdown the MTP3 link gracefully if it's being freed. More...
static int	_ofd_free (struct osmo_fd *ofd)
	Unregister a osmocom_fd from the event loop, and close it. More...
static int	event_link_down (sigtran_conn_t *conn)
	Take down a sigtran link. More...
static int	event_link_up (TALLOC_CTX *ctx, sigtran_conn_t **out, sigtran_conn_conf_t *conf)
	Bring up SCTP/M3UA/MTP3/SCCP. More...
static int	event_process_request (struct osmo_fd *ofd, unsigned int what)
	Processes a request for a new pipe from a worker thread. More...
static struct osmo_fd *	ofd_create (TALLOC_CTX *ctx, int fd, osmo_cb_func func, void *data)
	Register a new osmocom file descriptor callback. More...
int	sigtran_event_exit (void)
	Signal that libosmo should exit. More...
static void *	sigtran_event_loop (UNUSED void *instance)
	Enter the libosmo event loop. More...
int	sigtran_event_start (void)
	Start the libosmo event loop. More...
int	sigtran_event_submit (struct osmo_fd *ofd, sigtran_transaction_t *txn)
	Send response. More...
static int	sigtran_m3ua_route_from_conf (UNUSED TALLOC_CTX *ctx, struct mtp_m3ua_client_link *client, sigtran_m3ua_route_t *conf)
	Add a route to an m3ua_association. More...

Variables
int	ctrl_pipe [2] = { -1, -1 }
static bool	do_exit = false
static pthread_t	event_thread
static sem_t	event_thread_running

Detailed Description

separate eventing thread to run libosmocore's event loop

Id

6278db1a8aa116790bf03a75bdd213862a640cfb

libosmocore is not thread safe, none of the event loop access functions support synchronised access by multiple threads.

Writing a shim layer and overloading the libosmo functions would work but is likely to be fragile.

Instead, we run a special thread to handle all requests to SS7 entities.

This thread runs the libosmocore event loop, and select()s over the SCTP FDs libosmo* creates, and a pipe we create (to allow communication with worker threads).

You might except performance using this model to be terrible. But the fact that libosmo is entirely async, and there's no heavy crypto being performed, I suspect that this thread is unlikely to become a bottleneck.

In future when we have our own async event loop, we can look at submitting patches to libosmocore to allow integration with external event loops.

Note

We rely on the fact that writes to a pipe of less than PIPE_BUF, are atomic and not interleaved.

Author

Arran Cudbard-Bell

Copyright

2016 Network RADIUS SAS (licen.nosp@m.se@n.nosp@m.etwor.nosp@m.krad.nosp@m.ius.c.nosp@m.om)

Definition in file event.c.

Macro Definition Documentation

LOG_PREFIX

#define LOG_PREFIX   "sigtran"

Definition at line 59 of file event.c.

Typedef Documentation

osmo_cb_func

typedef int(* osmo_cb_func) (struct osmo_fd *fd, unsigned int what)

Definition at line 83 of file event.c.

Function Documentation

_mtp3_link_free()

static int _mtp3_link_free ( struct mtp_link *  mtp3_link )

static

Shutdown the MTP3 link gracefully if it's being freed.

Definition at line 130 of file event.c.

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_ofd_free()

static int _ofd_free ( struct osmo_fd *  ofd )

static

Unregister a osmocom_fd from the event loop, and close it.

Parameters

ofd	to unregister.

Returns

0.

Definition at line 90 of file event.c.

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event_link_down()

static int event_link_down ( sigtran_conn_t *  conn )

static

Take down a sigtran link.

Note

Probably need to do more than just freeing the memory

Definition at line 270 of file event.c.

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event_link_up()

static int event_link_up ( TALLOC_CTX *  ctx, sigtran_conn_t **  out, sigtran_conn_conf_t *  conf  )

static

Bring up SCTP/M3UA/MTP3/SCCP.

Note

The final version needs to be much more complex. We can only have one event loop per instance of rlm_sigtran, so we need to record link references and reuse existing SCTP/MTP3 connections where appropriate.

Parameters

[in]	ctx	to allocate connection data in.
[out]	out	where to write the new sigtran connection.
[in]	conf	for the connection. Specifies SCTP/M3UA/MTP3/SCCP parameters.

Returns

• 0 on success.
• -1 on failure.

Definition at line 188 of file event.c.

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event_process_request()

static int event_process_request ( struct osmo_fd *  ofd, unsigned int  what  )

static

Processes a request for a new pipe from a worker thread.

Parameters

ofd	for the main ctrl_pipe.
what	happened.

Returns

• 0 on success, with pointer written to registration pipe for new osmo_fd.
• -1 on error, with NULL pointer written to registration pipe.

Definition at line 340 of file event.c.

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ofd_create()

static struct osmo_fd* ofd_create ( TALLOC_CTX *  ctx, int  fd, osmo_cb_func  func, void *  data  )

static

Register a new osmocom file descriptor callback.

Parameters

ctx	to allocate osmocom_fd in.
fd	to associate with osmocom_fd .
func	to call when fd becomes readable.
data	private contextual data.

Returns

• NULL on error.
  • New osmocom_fd on success. Freeing unregisters osmocom_fd from event loop, and closes file descriptor.

Definition at line 109 of file event.c.

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sigtran_event_exit()

int sigtran_event_exit

(

void

)

Signal that libosmo should exit.

Definition at line 581 of file event.c.

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sigtran_event_loop()

static void* sigtran_event_loop ( UNUSED void *  instance )

static

Enter the libosmo event loop.

Will run until the thread is killed, or signalled to exit on the ctrl_pipe.

Definition at line 470 of file event.c.

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sigtran_event_start()

int sigtran_event_start

(

void

)

Start the libosmo event loop.

Definition at line 525 of file event.c.

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sigtran_event_submit()

int sigtran_event_submit	(	struct osmo_fd *	ofd,
		sigtran_transaction_t *	txn
	)

Send response.

Note

Works for both blocking and non-blocking sockets

Parameters

[in]	ofd	to write response notification to.
[in]	txn	we're confirming.

Definition at line 283 of file event.c.

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sigtran_m3ua_route_from_conf()

static int sigtran_m3ua_route_from_conf ( UNUSED TALLOC_CTX *  ctx, struct mtp_m3ua_client_link *  client, sigtran_m3ua_route_t *  conf  )

static

Add a route to an m3ua_association.

Definition at line 139 of file event.c.

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Variable Documentation

ctrl_pipe

int ctrl_pipe[2] = { -1, -1 }

Definition at line 78 of file event.c.

do_exit

bool do_exit = false

static

Definition at line 81 of file event.c.

event_thread

pthread_t event_thread

static

Definition at line 79 of file event.c.

event_thread_running

sem_t event_thread_running

static

Definition at line 80 of file event.c.