Merge "lock: Improve performance of DEBUG_THREADS."
[asterisk/asterisk.git] / main / framehook.c
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 2010, Digium, Inc.
5  *
6  * David Vossel <dvossel@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 FrameHooks Architecture
22  *
23  * \author David Vossel <dvossel@digium.com>
24  */
25
26 /*** MODULEINFO
27         <support_level>core</support_level>
28  ***/
29
30 #include "asterisk.h"
31
32 #include "asterisk/channel.h"
33 #include "asterisk/linkedlists.h"
34 #include "asterisk/framehook.h"
35 #include "asterisk/frame.h"
36
37 struct ast_framehook {
38         struct ast_framehook_interface i;
39         /*! This pointer to ast_channel the framehook is attached to. */
40         struct ast_channel *chan;
41         /*! the id representing this framehook on a channel */
42         unsigned int id;
43         /*! when set, this signals the read and write function to detach the hook */
44         int detach_and_destroy_me;
45         /*! list entry for ast_framehook_list object */
46         AST_LIST_ENTRY(ast_framehook) list;
47 };
48
49 struct ast_framehook_list {
50         /*! the number of hooks currently present */
51         unsigned int count;
52         /*! id for next framehook added */
53         unsigned int id_count;
54         AST_LIST_HEAD_NOLOCK(, ast_framehook) list;
55 };
56
57 enum framehook_detachment_mode
58 {
59         /*! Destroy the framehook outright. */
60         FRAMEHOOK_DETACH_DESTROY = 0,
61         /*! Remove the framehook from the channel, but don't destroy the data since
62          *  it will be used by a replacement framehook on another channel. */
63         FRAMEHOOK_DETACH_PRESERVE,
64 };
65
66 static void framehook_detach(struct ast_framehook *framehook, enum framehook_detachment_mode mode)
67 {
68         struct ast_frame *frame;
69         frame = framehook->i.event_cb(framehook->chan, NULL, AST_FRAMEHOOK_EVENT_DETACHED, framehook->i.data);
70         /* never assume anything about this function. If you can return a frame during
71          * the detached event, then assume someone will. */
72         if (frame) {
73                 ast_frfree(frame);
74         }
75         framehook->chan = NULL;
76
77         if (mode == FRAMEHOOK_DETACH_DESTROY && framehook->i.destroy_cb) {
78                 framehook->i.destroy_cb(framehook->i.data);
79         }
80         ast_free(framehook);
81 }
82
83 static struct ast_frame *framehook_list_push_event(struct ast_framehook_list *framehooks, struct ast_frame *frame, enum ast_framehook_event event)
84 {
85         struct ast_framehook *framehook;
86         struct ast_frame *original_frame;
87         int *skip;
88         size_t skip_size;
89
90         if (!framehooks) {
91                 return frame;
92         }
93
94         skip_size = sizeof(int) * framehooks->count;
95         skip = ast_alloca(skip_size);
96         memset(skip, 0, skip_size);
97
98         do {
99                 unsigned int num = 0;
100                 original_frame = frame;
101
102                 AST_LIST_TRAVERSE_SAFE_BEGIN(&framehooks->list, framehook, list) {
103                         if (framehook->detach_and_destroy_me) {
104                                 /* this guy is signaled for destruction */
105                                 AST_LIST_REMOVE_CURRENT(list);
106                                 framehook_detach(framehook, FRAMEHOOK_DETACH_DESTROY);
107                                 continue;
108                         }
109
110                         /* If this framehook has been marked as needing to be skipped, do so */
111                         if (skip[num]) {
112                                 num++;
113                                 continue;
114                         }
115
116                         frame = framehook->i.event_cb(framehook->chan, frame, event, framehook->i.data);
117
118                         if (frame != original_frame) {
119                                 /* To prevent looping we skip any framehooks that have already provided a modified frame */
120                                 skip[num] = 1;
121                                 break;
122                         }
123
124                         num++;
125                 }
126                 AST_LIST_TRAVERSE_SAFE_END;
127         } while (frame != original_frame);
128
129         return frame;
130 }
131
132 int ast_framehook_attach(struct ast_channel *chan, struct ast_framehook_interface *i)
133 {
134         struct ast_framehook *framehook;
135         struct ast_framehook_list *fh_list;
136         struct ast_frame *frame;
137         if (i->version != AST_FRAMEHOOK_INTERFACE_VERSION) {
138                 ast_log(LOG_ERROR, "Version '%hu' of framehook interface not what we compiled against (%i)\n",
139                         i->version, AST_FRAMEHOOK_INTERFACE_VERSION);
140                 return -1;
141         }
142         if (!i->event_cb || !(framehook = ast_calloc(1, sizeof(*framehook)))) {
143                 return -1;
144         }
145         framehook->i = *i;
146         framehook->chan = chan;
147
148         /* create the framehook list if it didn't already exist */
149         if (!ast_channel_framehooks(chan)) {
150                 if (!(fh_list = ast_calloc(1, sizeof(*ast_channel_framehooks(chan))))) {
151                         ast_free(framehook);
152                         return -1;
153                 }
154                 ast_channel_framehooks_set(chan, fh_list);
155         }
156
157         ast_channel_framehooks(chan)->count++;
158         framehook->id = ++ast_channel_framehooks(chan)->id_count;
159         AST_LIST_INSERT_TAIL(&ast_channel_framehooks(chan)->list, framehook, list);
160
161         /* Tell the event callback we're live and rocking */
162         frame = framehook->i.event_cb(framehook->chan, NULL, AST_FRAMEHOOK_EVENT_ATTACHED, framehook->i.data);
163
164         /* Never assume anything about this function. If you can return a frame during
165          * the attached event, then assume someone will. */
166         if (frame) {
167                 ast_frfree(frame);
168         }
169
170         if (ast_channel_is_bridged(chan)) {
171                 ast_channel_set_unbridged_nolock(chan, 1);
172         }
173
174         return framehook->id;
175 }
176
177 int ast_framehook_detach(struct ast_channel *chan, int id)
178 {
179         struct ast_framehook *framehook;
180         int res = -1;
181
182         if (!ast_channel_framehooks(chan)) {
183                 return res;
184         }
185
186         AST_LIST_TRAVERSE_SAFE_BEGIN(&ast_channel_framehooks(chan)->list, framehook, list) {
187                 if (framehook->id == id) {
188                         /* we mark for detachment rather than doing explicitly here because
189                          * it needs to be safe for this function to be called within the
190                          * event callback.  If we allowed the hook to actually be destroyed
191                          * immediately here, the event callback would crash on exit. */
192                         framehook->detach_and_destroy_me = 1;
193                         res = 0;
194                         break;
195                 }
196         }
197         AST_LIST_TRAVERSE_SAFE_END;
198
199         if (!res && ast_channel_is_bridged(chan)) {
200                 ast_channel_set_unbridged_nolock(chan, 1);
201         }
202
203         return res;
204 }
205
206 int ast_framehook_list_destroy(struct ast_channel *chan)
207 {
208         struct ast_framehook *framehook;
209
210         if (!ast_channel_framehooks(chan)) {
211                 return 0;
212         }
213         AST_LIST_TRAVERSE_SAFE_BEGIN(&ast_channel_framehooks(chan)->list, framehook, list) {
214                 AST_LIST_REMOVE_CURRENT(list);
215                 framehook_detach(framehook, FRAMEHOOK_DETACH_DESTROY);
216         }
217         AST_LIST_TRAVERSE_SAFE_END;
218         ast_free(ast_channel_framehooks(chan));
219         ast_channel_framehooks_set(chan, NULL);
220         return 0;
221 }
222
223 void ast_framehook_list_fixup(struct ast_channel *old_chan, struct ast_channel *new_chan)
224 {
225         struct ast_framehook *framehook;
226         int moved_framehook_id;
227
228         if (ast_channel_framehooks(new_chan)) {
229                 AST_LIST_TRAVERSE_SAFE_BEGIN(&ast_channel_framehooks(new_chan)->list, framehook, list) {
230                         if (framehook->i.disable_inheritance) {
231                                 ast_framehook_detach(new_chan, framehook->id);
232                                 continue;
233                         }
234
235                         if (framehook->i.chan_breakdown_cb) {
236                                 framehook->i.chan_breakdown_cb(framehook->i.data, framehook->id,
237                                         old_chan, new_chan);
238                         }
239                 }
240                 AST_LIST_TRAVERSE_SAFE_END;
241         }
242
243         if (!ast_channel_framehooks(old_chan)) {
244                 return;
245         }
246
247         if (!AST_LIST_EMPTY(&ast_channel_framehooks(old_chan)->list)
248                 && ast_channel_is_bridged(old_chan)) {
249                 ast_channel_set_unbridged_nolock(old_chan, 1);
250         }
251         while ((framehook = AST_LIST_REMOVE_HEAD(&ast_channel_framehooks(old_chan)->list, list))) {
252                 /* If inheritance is not allowed for this framehook, just destroy it. */
253                 if (framehook->i.disable_inheritance) {
254                         framehook_detach(framehook, FRAMEHOOK_DETACH_DESTROY);
255                         continue;
256                 }
257
258                 /* Otherwise move it to the other channel and perform any fixups set by the framehook interface */
259                 moved_framehook_id = ast_framehook_attach(new_chan, &framehook->i);
260                 if (moved_framehook_id < 0) {
261                         ast_log(LOG_WARNING, "Failed framehook copy during masquerade. Expect loss of features.\n");
262                         framehook_detach(framehook, FRAMEHOOK_DETACH_DESTROY);
263                 } else {
264                         if (framehook->i.chan_fixup_cb) {
265                                 framehook->i.chan_fixup_cb(framehook->i.data, moved_framehook_id,
266                                         old_chan, new_chan);
267                         }
268
269                         framehook_detach(framehook, FRAMEHOOK_DETACH_PRESERVE);
270                 }
271         }
272 }
273
274 int ast_framehook_list_is_empty(struct ast_framehook_list *framehooks)
275 {
276         if (!framehooks) {
277                 return 1;
278         }
279         return AST_LIST_EMPTY(&framehooks->list) ? 1 : 0;
280 }
281
282 int ast_framehook_list_contains_no_active(struct ast_framehook_list *framehooks)
283 {
284         return ast_framehook_list_contains_no_active_of_type(framehooks, 0);
285 }
286
287 int ast_framehook_list_contains_no_active_of_type(struct ast_framehook_list *framehooks,
288         enum ast_frame_type type)
289 {
290         struct ast_framehook *cur;
291
292         if (!framehooks) {
293                 return 1;
294         }
295
296         if (AST_LIST_EMPTY(&framehooks->list)) {
297                 return 1;
298         }
299
300         AST_LIST_TRAVERSE(&framehooks->list, cur, list) {
301                 if (cur->detach_and_destroy_me) {
302                         continue;
303                 }
304                 if (type && cur->i.consume_cb && !cur->i.consume_cb(cur->i.data, type)) {
305                         continue;
306                 }
307                 return 0;
308         }
309
310         return 1;
311 }
312
313 struct ast_frame *ast_framehook_list_write_event(struct ast_framehook_list *framehooks, struct ast_frame *frame)
314 {
315         return framehook_list_push_event(framehooks, frame, AST_FRAMEHOOK_EVENT_WRITE);
316 }
317
318 struct ast_frame *ast_framehook_list_read_event(struct ast_framehook_list *framehooks, struct ast_frame *frame)
319 {
320         return framehook_list_push_event(framehooks, frame, AST_FRAMEHOOK_EVENT_READ);
321 }