Asterisk - The Open Source Telephony Project  21.4.1
stasis_message_router.c
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1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2013, Digium, Inc.
5  *
6  * David M. Lee, II <dlee@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18 
19 /*! \file
20  *
21  * \brief Stasis message router implementation.
22  *
23  * \author David M. Lee, II <dlee@digium.com>
24  */
25 
26 /*** MODULEINFO
27  <support_level>core</support_level>
28  ***/
29 
30 #include "asterisk.h"
31 
32 #include "asterisk/astobj2.h"
33 #include "asterisk/stasis_message_router.h"
34 #include "asterisk/vector.h"
35 
36 /*! \internal */
38  /*! Message type handle by this route. */
40  /*! Callback function for incoming message processing. */
42  /*! Data pointer to be handed to the callback. */
43  void *data;
44 };
45 
47 
48 static struct stasis_message_route *route_table_find(struct route_table *table,
50 {
51  size_t idx;
52  struct stasis_message_route *route;
53 
54  /* While a linear search for routes may seem very inefficient, most
55  * route tables have six routes or less. For such small data, it's
56  * hard to beat a linear search. If we start having larger route
57  * tables, then we can look into containers with more efficient
58  * lookups.
59  */
60  for (idx = 0; idx < AST_VECTOR_SIZE(table); ++idx) {
61  route = AST_VECTOR_GET_ADDR(table, idx);
62  if (route->message_type == message_type) {
63  return route;
64  }
65  }
66 
67  return NULL;
68 }
69 
70 /*!
71  * \brief route_table comparator for AST_VECTOR_REMOVE_CMP_UNORDERED()
72  *
73  * \param elem Element to compare against
74  * \param value Value to compare with the vector element.
75  *
76  * \return 0 if element does not match.
77  * \return Non-zero if element matches.
78  */
79 #define ROUTE_TABLE_ELEM_CMP(elem, value) ((elem).message_type == (value))
80 
81 /*!
82  * \brief route_table vector element cleanup.
83  *
84  * \param elem Element to cleanup
85  */
86 #define ROUTE_TABLE_ELEM_CLEANUP(elem) ao2_cleanup((elem).message_type)
87 
88 static int route_table_remove(struct route_table *table,
89  struct stasis_message_type *message_type)
90 {
91  return AST_VECTOR_REMOVE_CMP_UNORDERED(table, message_type, ROUTE_TABLE_ELEM_CMP,
93 }
94 
95 static int route_table_add(struct route_table *table,
96  struct stasis_message_type *message_type,
98 {
99  struct stasis_message_route route;
100  int res;
101 
102  ast_assert(callback != NULL);
103  ast_assert(route_table_find(table, message_type) == NULL);
104 
105  route.message_type = ao2_bump(message_type);
106  route.callback = callback;
107  route.data = data;
108 
109  res = AST_VECTOR_APPEND(table, route);
110  if (res) {
112  }
113  return res;
114 }
115 
116 static void route_table_dtor(struct route_table *table)
117 {
118  size_t idx;
119  struct stasis_message_route *route;
120 
121  for (idx = 0; idx < AST_VECTOR_SIZE(table); ++idx) {
122  route = AST_VECTOR_GET_ADDR(table, idx);
123  ROUTE_TABLE_ELEM_CLEANUP(*route);
124  }
125  AST_VECTOR_FREE(table);
126 }
127 
128 /*! \internal */
130  /*! Subscription to the upstream topic */
132  /*! Subscribed routes */
134  /*! Subscribed routes for \ref stasis_cache_update messages */
136  /*! Route of last resort */
138 };
139 
140 static void router_dtor(void *obj)
141 {
142  struct stasis_message_router *router = obj;
143 
144  ast_assert(!stasis_subscription_is_subscribed(router->subscription));
145  ast_assert(stasis_subscription_is_done(router->subscription));
146 
147  router->subscription = NULL;
148 
149  route_table_dtor(&router->routes);
150  route_table_dtor(&router->cache_routes);
151 }
152 
153 static int find_route(
154  struct stasis_message_router *router,
155  struct stasis_message *message,
156  struct stasis_message_route *route_out)
157 {
158  struct stasis_message_route *route = NULL;
159  struct stasis_message_type *type = stasis_message_type(message);
160  SCOPED_AO2LOCK(lock, router);
161 
162  ast_assert(route_out != NULL);
163 
164  if (type == stasis_cache_update_type()) {
165  /* Find a cache route */
166  struct stasis_cache_update *update =
167  stasis_message_data(message);
168  route = route_table_find(&router->cache_routes, update->type);
169  }
170 
171  if (route == NULL) {
172  /* Find a regular route */
173  route = route_table_find(&router->routes, type);
174  }
175 
176  if (route == NULL && router->default_route.callback) {
177  /* Maybe the default route, then? */
178  route = &router->default_route;
179  }
180 
181  if (!route) {
182  return -1;
183  }
184 
185  *route_out = *route;
186  return 0;
187 }
188 
189 static void router_dispatch(void *data,
190  struct stasis_subscription *sub,
191  struct stasis_message *message)
192 {
193  struct stasis_message_router *router = data;
194  struct stasis_message_route route;
195 
196  if (find_route(router, message, &route) == 0) {
197  route.callback(route.data, sub, message);
198  }
199 
200  if (stasis_subscription_final_message(sub, message)) {
201  ao2_cleanup(router);
202  }
203 }
204 
205 static struct stasis_message_router *stasis_message_router_create_internal(
206  struct stasis_topic *topic, int use_thread_pool, const char *file, int lineno,
207  const char *func)
208 {
209  int res;
210  struct stasis_message_router *router;
211 
212  router = ao2_t_alloc(sizeof(*router), router_dtor, stasis_topic_name(topic));
213  if (!router) {
214  return NULL;
215  }
216 
217  res = 0;
218  res |= AST_VECTOR_INIT(&router->routes, 0);
219  res |= AST_VECTOR_INIT(&router->cache_routes, 0);
220  if (res) {
221  ao2_ref(router, -1);
222 
223  return NULL;
224  }
225 
226  if (use_thread_pool) {
227  router->subscription = __stasis_subscribe_pool(topic, router_dispatch, router, file, lineno, func);
228  } else {
229  router->subscription = __stasis_subscribe(topic, router_dispatch, router, file, lineno, func);
230  }
231 
232  if (!router->subscription) {
233  ao2_ref(router, -1);
234 
235  return NULL;
236  }
237 
238  /* We need to receive subscription change messages so we know when our subscription goes away */
240 
241  return router;
242 }
243 
244 struct stasis_message_router *__stasis_message_router_create(
245  struct stasis_topic *topic, const char *file, int lineno, const char *func)
246 {
247  return stasis_message_router_create_internal(topic, 0, file, lineno, func);
248 }
249 
250 struct stasis_message_router *__stasis_message_router_create_pool(
251  struct stasis_topic *topic, const char *file, int lineno, const char *func)
252 {
253  return stasis_message_router_create_internal(topic, 1, file, lineno, func);
254 }
255 
257 {
258  if (!router) {
259  return;
260  }
261 
262  ao2_lock(router);
263  router->subscription = stasis_unsubscribe(router->subscription);
264  ao2_unlock(router);
265 }
266 
268  struct stasis_message_router *router)
269 {
270  if (!router) {
271  return;
272  }
274 }
275 
277 {
278  if (!router) {
279  /* Null router is about as done as you can get */
280  return 1;
281  }
282 
284 }
285 
287  struct stasis_message *message)
288 {
289  ast_assert(router != NULL);
290 
291  ao2_bump(router);
292  stasis_publish_sync(router->subscription, message);
293  ao2_cleanup(router);
294 }
295 
297  long low_water, long high_water)
298 {
299  int res = -1;
300 
301  if (router) {
303  low_water, high_water);
304  }
305  return res;
306 }
307 
309  struct stasis_message_type *message_type,
310  stasis_subscription_cb callback, void *data)
311 {
312  int res;
313 
314  ast_assert(router != NULL);
315 
316  if (!message_type) {
317  /* Cannot route to NULL type. */
318  return -1;
319  }
320  ao2_lock(router);
321  res = route_table_add(&router->routes, message_type, callback, data);
322  if (!res) {
324  /* Until a specific message type was added we would already drop the message, so being
325  * selective now doesn't harm us. If we have a default route then we are already forced
326  * to filter nothing and messages will come in regardless.
327  */
329  }
330  ao2_unlock(router);
331  return res;
332 }
333 
335  struct stasis_message_type *message_type,
336  stasis_subscription_cb callback, void *data)
337 {
338  int res;
339 
340  ast_assert(router != NULL);
341 
342  if (!message_type) {
343  /* Cannot cache a route to NULL type. */
344  return -1;
345  }
346  ao2_lock(router);
347  res = route_table_add(&router->cache_routes, message_type, callback, data);
348  if (!res) {
351  }
352  ao2_unlock(router);
353  return res;
354 }
355 
357  struct stasis_message_type *message_type)
358 {
359  ast_assert(router != NULL);
360 
361  if (!message_type) {
362  /* Cannot remove a NULL type. */
363  return;
364  }
365  ao2_lock(router);
366  route_table_remove(&router->routes, message_type);
367  ao2_unlock(router);
368 }
369 
371  struct stasis_message_router *router,
372  struct stasis_message_type *message_type)
373 {
374  ast_assert(router != NULL);
375 
376  if (!message_type) {
377  /* Cannot remove a NULL type. */
378  return;
379  }
380  ao2_lock(router);
381  route_table_remove(&router->cache_routes, message_type);
382  ao2_unlock(router);
383 }
384 
386  stasis_subscription_cb callback,
387  void *data)
388 {
389  stasis_message_router_set_formatters_default(router, callback, data, STASIS_SUBSCRIPTION_FORMATTER_NONE);
390 
391  /* While this implementation can never fail, it used to be able to */
392  return 0;
393 }
394 
396  stasis_subscription_cb callback,
397  void *data,
399 {
400  ast_assert(router != NULL);
401  ast_assert(callback != NULL);
402 
404 
405  ao2_lock(router);
406  router->default_route.callback = callback;
407  router->default_route.data = data;
408  ao2_unlock(router);
409 
410  if (formatters == STASIS_SUBSCRIPTION_FORMATTER_NONE) {
411  /* Formatters govern what messages the default callback get, so it is only if none is
412  * specified that we accept all messages regardless.
413  */
415  }
416 }
417 
420 {
421  ast_assert(router != NULL);
422 
424 
425  return;
426 }
#define AST_VECTOR_FREE(vec)
Deallocates this vector.
Definition: vector.h:174
Asterisk main include file. File version handling, generic pbx functions.
int stasis_message_router_add(struct stasis_message_router *router, struct stasis_message_type *message_type, stasis_subscription_cb callback, void *data)
Add a route to a message router.
#define AST_VECTOR_REMOVE_CMP_UNORDERED(vec, value, cmp, cleanup)
Remove an element from a vector that matches the given comparison.
Definition: vector.h:488
int stasis_message_router_set_congestion_limits(struct stasis_message_router *router, long low_water, long high_water)
Set the high and low alert water marks of the stasis message router.
struct route_table cache_routes
#define ROUTE_TABLE_ELEM_CMP(elem, value)
route_table comparator for AST_VECTOR_REMOVE_CMP_UNORDERED()
int stasis_subscription_is_subscribed(const struct stasis_subscription *sub)
Returns whether a subscription is currently subscribed.
Definition: stasis.c:1150
#define AST_VECTOR_APPEND(vec, elem)
Append an element to a vector, growing the vector if needed.
Definition: vector.h:256
void stasis_message_router_accept_formatters(struct stasis_message_router *router, enum stasis_subscription_message_formatters formatters)
Indicate to a message router that we are interested in messages with one or more formatters.
struct stasis_message_type * stasis_message_type(const struct stasis_message *msg)
Get the message type for a stasis_message.
int stasis_subscription_set_filter(struct stasis_subscription *subscription, enum stasis_subscription_message_filter filter)
Set the message type filtering level on a subscription.
Definition: stasis.c:1077
void stasis_message_router_set_formatters_default(struct stasis_message_router *router, stasis_subscription_cb callback, void *data, enum stasis_subscription_message_formatters formatters)
Sets the default route of a router with formatters.
int stasis_message_router_add_cache_update(struct stasis_message_router *router, struct stasis_message_type *message_type, stasis_subscription_cb callback, void *data)
Add a route for stasis_cache_update messages to a message router.
int stasis_message_router_is_done(struct stasis_message_router *router)
Returns whether router has received its final message.
void stasis_message_router_unsubscribe_and_join(struct stasis_message_router *router)
Unsubscribe the router from the upstream topic, blocking until the final message has been processed...
int stasis_subscription_set_congestion_limits(struct stasis_subscription *subscription, long low_water, long high_water)
Set the high and low alert water marks of the stasis subscription.
Definition: stasis.c:1011
#define ao2_bump(obj)
Bump refcount on an AO2 object by one, returning the object.
Definition: astobj2.h:480
#define AST_VECTOR_INIT(vec, size)
Initialize a vector.
Definition: vector.h:113
ast_mutex_t lock
#define AST_VECTOR_GET_ADDR(vec, idx)
Get an address of element in a vector.
Definition: vector.h:668
#define ao2_ref(o, delta)
Reference/unreference an object and return the old refcount.
Definition: astobj2.h:459
struct stasis_message_type * stasis_cache_update_type(void)
Message type for cache update messages.
#define AST_VECTOR(name, type)
Define a vector structure.
Definition: vector.h:44
Cache update message.
Definition: stasis.h:965
void stasis_subscription_accept_formatters(struct stasis_subscription *subscription, enum stasis_subscription_message_formatters formatters)
Indicate to a subscription that we are interested in messages with one or more formatters.
Definition: stasis.c:1093
#define ROUTE_TABLE_ELEM_CLEANUP(elem)
route_table vector element cleanup.
void * stasis_message_data(const struct stasis_message *msg)
Get the data contained in a message.
struct stasis_message_route default_route
struct stasis_message_type * type
Convenience reference to snapshot type.
Definition: stasis.h:967
const char * stasis_topic_name(const struct stasis_topic *topic)
Return the name of a topic.
Definition: stasis.c:627
struct stasis_subscription * stasis_unsubscribe(struct stasis_subscription *subscription)
Cancel a subscription.
Definition: stasis.c:971
void(* stasis_subscription_cb)(void *data, struct stasis_subscription *sub, struct stasis_message *message)
Callback function type for Stasis subscriptions.
Definition: stasis.h:611
int stasis_subscription_final_message(struct stasis_subscription *sub, struct stasis_message *msg)
Determine whether a message is the final message to be received on a subscription.
Definition: stasis.c:1174
void stasis_message_router_remove(struct stasis_message_router *router, struct stasis_message_type *message_type)
Remove a route from a message router.
#define SCOPED_AO2LOCK(varname, obj)
scoped lock specialization for ao2 mutexes.
Definition: lock.h:604
struct stasis_subscription * stasis_unsubscribe_and_join(struct stasis_subscription *subscription)
Cancel a subscription, blocking until the last message is processed.
Definition: stasis.c:1134
Vector container support.
struct stasis_subscription * __stasis_subscribe_pool(struct stasis_topic *topic, stasis_subscription_cb callback, void *data, const char *file, int lineno, const char *func)
Create a subscription whose callbacks occur on a thread pool.
Definition: stasis.c:953
void stasis_publish_sync(struct stasis_subscription *sub, struct stasis_message *message)
Publish a message to a topic's subscribers, synchronizing on the specified subscriber.
Definition: stasis.c:1516
void stasis_message_router_unsubscribe(struct stasis_message_router *router)
Unsubscribe the router from the upstream topic.
void stasis_message_router_remove_cache_update(struct stasis_message_router *router, struct stasis_message_type *message_type)
Remove a cache route from a message router.
int stasis_subscription_is_done(struct stasis_subscription *subscription)
Returns whether subscription has received its final message.
Definition: stasis.c:1118
void stasis_message_router_publish_sync(struct stasis_message_router *router, struct stasis_message *message)
Publish a message to a message router's subscription synchronously.
struct stasis_subscription * __stasis_subscribe(struct stasis_topic *topic, stasis_subscription_cb callback, void *data, const char *file, int lineno, const char *func)
Create a subscription.
Definition: stasis.c:942
stasis_subscription_cb callback
int stasis_subscription_accept_message_type(struct stasis_subscription *subscription, const struct stasis_message_type *type)
Indicate to a subscription that we are interested in a message type.
Definition: stasis.c:1023
struct stasis_subscription * subscription
int stasis_message_router_set_default(struct stasis_message_router *router, stasis_subscription_cb callback, void *data)
Sets the default route of a router.
struct stasis_message_type * stasis_subscription_change_type(void)
Gets the message type for subscription change notices.
struct stasis_message_type * message_type
stasis_subscription_message_formatters
Stasis subscription formatter filters.
Definition: stasis.h:308
#define AST_VECTOR_SIZE(vec)
Get the number of elements in a vector.
Definition: vector.h:609