1/***
2  This file is part of avahi.
3
4  avahi is free software; you can redistribute it and/or modify it
5  under the terms of the GNU Lesser General Public License as
6  published by the Free Software Foundation; either version 2.1 of the
7  License, or (at your option) any later version.
8
9  avahi is distributed in the hope that it will be useful, but WITHOUT
10  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
12  Public License for more details.
13
14  You should have received a copy of the GNU Lesser General Public
15  License along with avahi; if not, write to the Free Software
16  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
17  USA.
18***/
19
20#ifdef HAVE_CONFIG_H
21#include <config.h>
22#endif
23
24#include <stdlib.h>
25
26#include <avahi-common/domain.h>
27#include <avahi-common/timeval.h>
28#include "avahi-common/avahi-malloc.h"
29
30#include "probe-sched.h"
31#include "log.h"
32#include "rr-util.h"
33
34#define AVAHI_PROBE_HISTORY_MSEC 150
35#define AVAHI_PROBE_DEFER_MSEC 50
36
37typedef struct AvahiProbeJob AvahiProbeJob;
38
39struct AvahiProbeJob {
40    AvahiProbeScheduler *scheduler;
41    AvahiTimeEvent *time_event;
42
43    int chosen; /* Use for packet assembling */
44    int done;
45    struct timeval delivery;
46
47    AvahiRecord *record;
48
49    AVAHI_LLIST_FIELDS(AvahiProbeJob, jobs);
50};
51
52struct AvahiProbeScheduler {
53    AvahiInterface *interface;
54    AvahiTimeEventQueue *time_event_queue;
55
56    AVAHI_LLIST_HEAD(AvahiProbeJob, jobs);
57    AVAHI_LLIST_HEAD(AvahiProbeJob, history);
58};
59
60static AvahiProbeJob* job_new(AvahiProbeScheduler *s, AvahiRecord *record, int done) {
61    AvahiProbeJob *pj;
62
63    assert(s);
64    assert(record);
65
66    if (!(pj = avahi_new(AvahiProbeJob, 1))) {
67        avahi_log_error(__FILE__": Out of memory");
68        return NULL; /* OOM */
69    }
70
71    pj->scheduler = s;
72    pj->record = avahi_record_ref(record);
73    pj->time_event = NULL;
74    pj->chosen = 0;
75
76    if ((pj->done = done))
77        AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->history, pj);
78    else
79        AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->jobs, pj);
80
81    return pj;
82}
83
84static void job_free(AvahiProbeScheduler *s, AvahiProbeJob *pj) {
85    assert(pj);
86
87    if (pj->time_event)
88        avahi_time_event_free(pj->time_event);
89
90    if (pj->done)
91        AVAHI_LLIST_REMOVE(AvahiProbeJob, jobs, s->history, pj);
92    else
93        AVAHI_LLIST_REMOVE(AvahiProbeJob, jobs, s->jobs, pj);
94
95    avahi_record_unref(pj->record);
96    avahi_free(pj);
97}
98
99static void elapse_callback(AvahiTimeEvent *e, void* data);
100
101static void job_set_elapse_time(AvahiProbeScheduler *s, AvahiProbeJob *pj, unsigned msec, unsigned jitter) {
102    struct timeval tv;
103
104    assert(s);
105    assert(pj);
106
107    avahi_elapse_time(&tv, msec, jitter);
108
109    if (pj->time_event)
110        avahi_time_event_update(pj->time_event, &tv);
111    else
112        pj->time_event = avahi_time_event_new(s->time_event_queue, &tv, elapse_callback, pj);
113}
114
115static void job_mark_done(AvahiProbeScheduler *s, AvahiProbeJob *pj) {
116    assert(s);
117    assert(pj);
118
119    assert(!pj->done);
120
121    AVAHI_LLIST_REMOVE(AvahiProbeJob, jobs, s->jobs, pj);
122    AVAHI_LLIST_PREPEND(AvahiProbeJob, jobs, s->history, pj);
123
124    pj->done = 1;
125
126    job_set_elapse_time(s, pj, AVAHI_PROBE_HISTORY_MSEC, 0);
127    gettimeofday(&pj->delivery, NULL);
128}
129
130AvahiProbeScheduler *avahi_probe_scheduler_new(AvahiInterface *i) {
131    AvahiProbeScheduler *s;
132
133    assert(i);
134
135    if (!(s = avahi_new(AvahiProbeScheduler, 1))) {
136        avahi_log_error(__FILE__": Out of memory");
137        return NULL;
138    }
139
140    s->interface = i;
141    s->time_event_queue = i->monitor->server->time_event_queue;
142
143    AVAHI_LLIST_HEAD_INIT(AvahiProbeJob, s->jobs);
144    AVAHI_LLIST_HEAD_INIT(AvahiProbeJob, s->history);
145
146    return s;
147}
148
149void avahi_probe_scheduler_free(AvahiProbeScheduler *s) {
150    assert(s);
151
152    avahi_probe_scheduler_clear(s);
153    avahi_free(s);
154}
155
156void avahi_probe_scheduler_clear(AvahiProbeScheduler *s) {
157    assert(s);
158
159    while (s->jobs)
160        job_free(s, s->jobs);
161    while (s->history)
162        job_free(s, s->history);
163}
164
165static int packet_add_probe_query(AvahiProbeScheduler *s, AvahiDnsPacket *p, AvahiProbeJob *pj) {
166    size_t size;
167    AvahiKey *k;
168    int b;
169
170    assert(s);
171    assert(p);
172    assert(pj);
173
174    assert(!pj->chosen);
175
176    /* Estimate the size for this record */
177    size =
178        avahi_key_get_estimate_size(pj->record->key) +
179        avahi_record_get_estimate_size(pj->record);
180
181    /* Too large */
182    if (size > avahi_dns_packet_space(p))
183        return 0;
184
185    /* Create the probe query */
186    if (!(k = avahi_key_new(pj->record->key->name, pj->record->key->clazz, AVAHI_DNS_TYPE_ANY)))
187        return 0; /* OOM */
188
189    b = !!avahi_dns_packet_append_key(p, k, 0);
190    assert(b);
191
192    /* Mark this job for addition to the packet */
193    pj->chosen = 1;
194
195    /* Scan for more jobs whith matching key pattern */
196    for (pj = s->jobs; pj; pj = pj->jobs_next) {
197        if (pj->chosen)
198            continue;
199
200        /* Does the record match the probe? */
201        if (k->clazz != pj->record->key->clazz || !avahi_domain_equal(k->name, pj->record->key->name))
202            continue;
203
204        /* This job wouldn't fit in */
205        if (avahi_record_get_estimate_size(pj->record) > avahi_dns_packet_space(p))
206            break;
207
208        /* Mark this job for addition to the packet */
209        pj->chosen = 1;
210    }
211
212    avahi_key_unref(k);
213
214    return 1;
215}
216
217static void elapse_callback(AVAHI_GCC_UNUSED AvahiTimeEvent *e, void* data) {
218    AvahiProbeJob *pj = data, *next;
219    AvahiProbeScheduler *s;
220    AvahiDnsPacket *p;
221    unsigned n;
222
223    assert(pj);
224    s = pj->scheduler;
225
226    if (pj->done) {
227        /* Lets remove it  from the history */
228        job_free(s, pj);
229        return;
230    }
231
232    if (!(p = avahi_dns_packet_new_query(s->interface->hardware->mtu)))
233        return; /* OOM */
234    n = 1;
235
236    /* Add the import probe */
237    if (!packet_add_probe_query(s, p, pj)) {
238        size_t size;
239        AvahiKey *k;
240        int b;
241
242        avahi_dns_packet_free(p);
243
244        /* The probe didn't fit in the package, so let's allocate a larger one */
245
246        size =
247            avahi_key_get_estimate_size(pj->record->key) +
248            avahi_record_get_estimate_size(pj->record) +
249            AVAHI_DNS_PACKET_HEADER_SIZE;
250
251        if (!(p = avahi_dns_packet_new_query(size + AVAHI_DNS_PACKET_EXTRA_SIZE)))
252            return; /* OOM */
253
254        if (!(k = avahi_key_new(pj->record->key->name, pj->record->key->clazz, AVAHI_DNS_TYPE_ANY))) {
255            avahi_dns_packet_free(p);
256            return;  /* OOM */
257        }
258
259        b = avahi_dns_packet_append_key(p, k, 0) && avahi_dns_packet_append_record(p, pj->record, 0, 0);
260        avahi_key_unref(k);
261
262        if (b) {
263            avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, 1);
264            avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, 1);
265            avahi_interface_send_packet(s->interface, p);
266        } else
267            avahi_log_warn("Probe record too large, cannot send");
268
269        avahi_dns_packet_free(p);
270        job_mark_done(s, pj);
271
272        return;
273    }
274
275    /* Try to fill up packet with more probes, if available */
276    for (pj = s->jobs; pj; pj = pj->jobs_next) {
277
278        if (pj->chosen)
279            continue;
280
281        if (!packet_add_probe_query(s, p, pj))
282            break;
283
284        n++;
285    }
286
287    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_QDCOUNT, n);
288
289    n = 0;
290
291    /* Now add the chosen records to the authorative section */
292    for (pj = s->jobs; pj; pj = next) {
293
294        next = pj->jobs_next;
295
296        if (!pj->chosen)
297            continue;
298
299        if (!avahi_dns_packet_append_record(p, pj->record, 0, 0)) {
300/*             avahi_log_warn("Bad probe size estimate!"); */
301
302            /* Unmark all following jobs */
303            for (; pj; pj = pj->jobs_next)
304                pj->chosen = 0;
305
306            break;
307        }
308
309        job_mark_done(s, pj);
310
311        n ++;
312    }
313
314    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_NSCOUNT, n);
315
316    /* Send it now */
317    avahi_interface_send_packet(s->interface, p);
318    avahi_dns_packet_free(p);
319}
320
321static AvahiProbeJob* find_scheduled_job(AvahiProbeScheduler *s, AvahiRecord *record) {
322    AvahiProbeJob *pj;
323
324    assert(s);
325    assert(record);
326
327    for (pj = s->jobs; pj; pj = pj->jobs_next) {
328        assert(!pj->done);
329
330        if (avahi_record_equal_no_ttl(pj->record, record))
331            return pj;
332    }
333
334    return NULL;
335}
336
337static AvahiProbeJob* find_history_job(AvahiProbeScheduler *s, AvahiRecord *record) {
338    AvahiProbeJob *pj;
339
340    assert(s);
341    assert(record);
342
343    for (pj = s->history; pj; pj = pj->jobs_next) {
344        assert(pj->done);
345
346        if (avahi_record_equal_no_ttl(pj->record, record)) {
347            /* Check whether this entry is outdated */
348
349            if (avahi_age(&pj->delivery) > AVAHI_PROBE_HISTORY_MSEC*1000) {
350                /* it is outdated, so let's remove it */
351                job_free(s, pj);
352                return NULL;
353            }
354
355            return pj;
356        }
357    }
358
359    return NULL;
360}
361
362int avahi_probe_scheduler_post(AvahiProbeScheduler *s, AvahiRecord *record, int immediately) {
363    AvahiProbeJob *pj;
364    struct timeval tv;
365
366    assert(s);
367    assert(record);
368    assert(!avahi_key_is_pattern(record->key));
369
370    if ((pj = find_history_job(s, record)))
371        return 0;
372
373    avahi_elapse_time(&tv, immediately ? 0 : AVAHI_PROBE_DEFER_MSEC, 0);
374
375    if ((pj = find_scheduled_job(s, record))) {
376
377        if (avahi_timeval_compare(&tv, &pj->delivery) < 0) {
378            /* If the new entry should be scheduled earlier, update the old entry */
379            pj->delivery = tv;
380            avahi_time_event_update(pj->time_event, &pj->delivery);
381        }
382
383        return 1;
384    } else {
385        /* Create a new job and schedule it */
386        if (!(pj = job_new(s, record, 0)))
387            return 0; /* OOM */
388
389        pj->delivery = tv;
390        pj->time_event = avahi_time_event_new(s->time_event_queue, &pj->delivery, elapse_callback, pj);
391
392
393/*     avahi_log_debug("Accepted new probe job."); */
394
395        return 1;
396    }
397}
398