aboutsummaryrefslogtreecommitdiff
path: root/lib/conncache.c
blob: 0ac38497c47304a201812880a52e2c4f4a64fb8b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2012 - 2016, Linus Nielsen Feltzing, <linus@haxx.se>
 * Copyright (C) 2012 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#include <curl/curl.h>

#include "urldata.h"
#include "url.h"
#include "progress.h"
#include "multiif.h"
#include "sendf.h"
#include "conncache.h"
#include "share.h"
#include "sigpipe.h"
#include "connect.h"

/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"

#ifdef CURLDEBUG
/* the debug versions of these macros make extra certain that the lock is
   never doubly locked or unlocked */
#define CONN_LOCK(x) if((x)->share) {                                   \
    Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE); \
    DEBUGASSERT(!(x)->state.conncache_lock);                            \
    (x)->state.conncache_lock = TRUE;                                   \
  }

#define CONN_UNLOCK(x) if((x)->share) {                                 \
    DEBUGASSERT((x)->state.conncache_lock);                             \
    (x)->state.conncache_lock = FALSE;                                  \
    Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT);                     \
  }
#else
#define CONN_LOCK(x) if((x)->share)                                     \
    Curl_share_lock((x), CURL_LOCK_DATA_CONNECT, CURL_LOCK_ACCESS_SINGLE)
#define CONN_UNLOCK(x) if((x)->share)                   \
    Curl_share_unlock((x), CURL_LOCK_DATA_CONNECT)
#endif

static void conn_llist_dtor(void *user, void *element)
{
  struct connectdata *conn = element;
  (void)user;
  conn->bundle = NULL;
}

static CURLcode bundle_create(struct Curl_easy *data,
                              struct connectbundle **cb_ptr)
{
  (void)data;
  DEBUGASSERT(*cb_ptr == NULL);
  *cb_ptr = malloc(sizeof(struct connectbundle));
  if(!*cb_ptr)
    return CURLE_OUT_OF_MEMORY;

  (*cb_ptr)->num_connections = 0;
  (*cb_ptr)->multiuse = BUNDLE_UNKNOWN;

  Curl_llist_init(&(*cb_ptr)->conn_list, (curl_llist_dtor) conn_llist_dtor);
  return CURLE_OK;
}

static void bundle_destroy(struct connectbundle *cb_ptr)
{
  if(!cb_ptr)
    return;

  Curl_llist_destroy(&cb_ptr->conn_list, NULL);

  free(cb_ptr);
}

/* Add a connection to a bundle */
static void bundle_add_conn(struct connectbundle *cb_ptr,
                            struct connectdata *conn)
{
  Curl_llist_insert_next(&cb_ptr->conn_list, cb_ptr->conn_list.tail, conn,
                         &conn->bundle_node);
  conn->bundle = cb_ptr;
  cb_ptr->num_connections++;
}

/* Remove a connection from a bundle */
static int bundle_remove_conn(struct connectbundle *cb_ptr,
                              struct connectdata *conn)
{
  struct curl_llist_element *curr;

  curr = cb_ptr->conn_list.head;
  while(curr) {
    if(curr->ptr == conn) {
      Curl_llist_remove(&cb_ptr->conn_list, curr, NULL);
      cb_ptr->num_connections--;
      conn->bundle = NULL;
      return 1; /* we removed a handle */
    }
    curr = curr->next;
  }
  return 0;
}

static void free_bundle_hash_entry(void *freethis)
{
  struct connectbundle *b = (struct connectbundle *) freethis;

  bundle_destroy(b);
}

int Curl_conncache_init(struct conncache *connc, int size)
{
  int rc;

  /* allocate a new easy handle to use when closing cached connections */
  connc->closure_handle = curl_easy_init();
  if(!connc->closure_handle)
    return 1; /* bad */

  rc = Curl_hash_init(&connc->hash, size, Curl_hash_str,
                      Curl_str_key_compare, free_bundle_hash_entry);
  if(rc) {
    Curl_close(connc->closure_handle);
    connc->closure_handle = NULL;
  }
  else
    connc->closure_handle->state.conn_cache = connc;

  return rc;
}

void Curl_conncache_destroy(struct conncache *connc)
{
  if(connc)
    Curl_hash_destroy(&connc->hash);
}

/* creates a key to find a bundle for this connection */
static void hashkey(struct connectdata *conn, char *buf,
                    size_t len) /* something like 128 is fine */
{
  const char *hostname;

  if(conn->bits.socksproxy)
    hostname = conn->socks_proxy.host.name;
  else if(conn->bits.httpproxy)
    hostname = conn->http_proxy.host.name;
  else if(conn->bits.conn_to_host)
    hostname = conn->conn_to_host.name;
  else
    hostname = conn->host.name;

  DEBUGASSERT(len > 32);

  /* put the number first so that the hostname gets cut off if too long */
  msnprintf(buf, len, "%ld%s", conn->port, hostname);
}

void Curl_conncache_unlock(struct Curl_easy *data)
{
  CONN_UNLOCK(data);
}

/* Returns number of connections currently held in the connection cache.
   Locks/unlocks the cache itself!
*/
size_t Curl_conncache_size(struct Curl_easy *data)
{
  size_t num;
  CONN_LOCK(data);
  num = data->state.conn_cache->num_conn;
  CONN_UNLOCK(data);
  return num;
}

/* Returns number of connections currently held in the connections's bundle
   Locks/unlocks the cache itself!
*/
size_t Curl_conncache_bundle_size(struct connectdata *conn)
{
  size_t num;
  CONN_LOCK(conn->data);
  num = conn->bundle->num_connections;
  CONN_UNLOCK(conn->data);
  return num;
}

/* Look up the bundle with all the connections to the same host this
   connectdata struct is setup to use.

   **NOTE**: When it returns, it holds the connection cache lock! */
struct connectbundle *Curl_conncache_find_bundle(struct connectdata *conn,
                                                 struct conncache *connc)
{
  struct connectbundle *bundle = NULL;
  CONN_LOCK(conn->data);
  if(connc) {
    char key[128];
    hashkey(conn, key, sizeof(key));
    bundle = Curl_hash_pick(&connc->hash, key, strlen(key));
  }

  return bundle;
}

static bool conncache_add_bundle(struct conncache *connc,
                                 char *key,
                                 struct connectbundle *bundle)
{
  void *p = Curl_hash_add(&connc->hash, key, strlen(key), bundle);

  return p?TRUE:FALSE;
}

static void conncache_remove_bundle(struct conncache *connc,
                                    struct connectbundle *bundle)
{
  struct curl_hash_iterator iter;
  struct curl_hash_element *he;

  if(!connc)
    return;

  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    if(he->ptr == bundle) {
      /* The bundle is destroyed by the hash destructor function,
         free_bundle_hash_entry() */
      Curl_hash_delete(&connc->hash, he->key, he->key_len);
      return;
    }

    he = Curl_hash_next_element(&iter);
  }
}

CURLcode Curl_conncache_add_conn(struct conncache *connc,
                                 struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  struct connectbundle *bundle;
  struct connectbundle *new_bundle = NULL;
  struct Curl_easy *data = conn->data;

  /* *find_bundle() locks the connection cache */
  bundle = Curl_conncache_find_bundle(conn, data->state.conn_cache);
  if(!bundle) {
    int rc;
    char key[128];

    result = bundle_create(data, &new_bundle);
    if(result) {
      goto unlock;
    }

    hashkey(conn, key, sizeof(key));
    rc = conncache_add_bundle(data->state.conn_cache, key, new_bundle);

    if(!rc) {
      bundle_destroy(new_bundle);
      result = CURLE_OUT_OF_MEMORY;
      goto unlock;
    }
    bundle = new_bundle;
  }

  bundle_add_conn(bundle, conn);
  conn->connection_id = connc->next_connection_id++;
  connc->num_conn++;

  DEBUGF(infof(conn->data, "Added connection %ld. "
               "The cache now contains %zu members\n",
               conn->connection_id, connc->num_conn));

  unlock:
  CONN_UNLOCK(data);

  return result;
}

/*
 * Removes the connectdata object from the connection cache *and* clears the
 * ->data pointer association. Pass TRUE/FALSE in the 'lock' argument
 * depending on if the parent function already holds the lock or not.
 */
void Curl_conncache_remove_conn(struct Curl_easy *data,
                                struct connectdata *conn, bool lock)
{
  struct connectbundle *bundle = conn->bundle;
  struct conncache *connc = data->state.conn_cache;

  /* The bundle pointer can be NULL, since this function can be called
     due to a failed connection attempt, before being added to a bundle */
  if(bundle) {
    if(lock) {
      CONN_LOCK(data);
    }
    bundle_remove_conn(bundle, conn);
    if(bundle->num_connections == 0)
      conncache_remove_bundle(connc, bundle);
    conn->bundle = NULL; /* removed from it */
    if(connc) {
      connc->num_conn--;
      DEBUGF(infof(data, "The cache now contains %zu members\n",
                   connc->num_conn));
    }
    conn->data = NULL; /* clear the association */
    if(lock) {
      CONN_UNLOCK(data);
    }
  }
}

/* This function iterates the entire connection cache and calls the function
   func() with the connection pointer as the first argument and the supplied
   'param' argument as the other.

   The conncache lock is still held when the callback is called. It needs it,
   so that it can safely continue traversing the lists once the callback
   returns.

   Returns 1 if the loop was aborted due to the callback's return code.

   Return 0 from func() to continue the loop, return 1 to abort it.
 */
bool Curl_conncache_foreach(struct Curl_easy *data,
                            struct conncache *connc,
                            void *param,
                            int (*func)(struct connectdata *conn, void *param))
{
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;

  if(!connc)
    return FALSE;

  CONN_LOCK(data);
  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectbundle *bundle;

    bundle = he->ptr;
    he = Curl_hash_next_element(&iter);

    curr = bundle->conn_list.head;
    while(curr) {
      /* Yes, we need to update curr before calling func(), because func()
         might decide to remove the connection */
      struct connectdata *conn = curr->ptr;
      curr = curr->next;

      if(1 == func(conn, param)) {
        CONN_UNLOCK(data);
        return TRUE;
      }
    }
  }
  CONN_UNLOCK(data);
  return FALSE;
}

/* Return the first connection found in the cache. Used when closing all
   connections.

   NOTE: no locking is done here as this is presumably only done when cleaning
   up a cache!
*/
struct connectdata *
Curl_conncache_find_first_connection(struct conncache *connc)
{
  struct curl_hash_iterator iter;
  struct curl_hash_element *he;
  struct connectbundle *bundle;

  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct curl_llist_element *curr;
    bundle = he->ptr;

    curr = bundle->conn_list.head;
    if(curr) {
      return curr->ptr;
    }

    he = Curl_hash_next_element(&iter);
  }

  return NULL;
}

/*
 * Give ownership of a connection back to the connection cache. Might
 * disconnect the oldest existing in there to make space.
 *
 * Return TRUE if stored, FALSE if closed.
 */
bool Curl_conncache_return_conn(struct connectdata *conn)
{
  struct Curl_easy *data = conn->data;

  /* data->multi->maxconnects can be negative, deal with it. */
  size_t maxconnects =
    (data->multi->maxconnects < 0) ? data->multi->num_easy * 4:
    data->multi->maxconnects;
  struct connectdata *conn_candidate = NULL;

  if(maxconnects > 0 &&
     Curl_conncache_size(data) > maxconnects) {
    infof(data, "Connection cache is full, closing the oldest one.\n");

    conn_candidate = Curl_conncache_extract_oldest(data);
    if(conn_candidate) {
      /* the winner gets the honour of being disconnected */
      (void)Curl_disconnect(data, conn_candidate, /* dead_connection */ FALSE);
    }
  }

  return (conn_candidate == conn) ? FALSE : TRUE;

}

/*
 * This function finds the connection in the connection bundle that has been
 * unused for the longest time.
 *
 * Does not lock the connection cache!
 *
 * Returns the pointer to the oldest idle connection, or NULL if none was
 * found.
 */
struct connectdata *
Curl_conncache_extract_bundle(struct Curl_easy *data,
                              struct connectbundle *bundle)
{
  struct curl_llist_element *curr;
  timediff_t highscore = -1;
  timediff_t score;
  struct curltime now;
  struct connectdata *conn_candidate = NULL;
  struct connectdata *conn;

  (void)data;

  now = Curl_now();

  curr = bundle->conn_list.head;
  while(curr) {
    conn = curr->ptr;

    if(!CONN_INUSE(conn)) {
      /* Set higher score for the age passed since the connection was used */
      score = Curl_timediff(now, conn->now);

      if(score > highscore) {
        highscore = score;
        conn_candidate = conn;
      }
    }
    curr = curr->next;
  }
  if(conn_candidate) {
    /* remove it to prevent another thread from nicking it */
    bundle_remove_conn(bundle, conn_candidate);
    data->state.conn_cache->num_conn--;
    DEBUGF(infof(data, "The cache now contains %zu members\n",
                 data->state.conn_cache->num_conn));
    conn_candidate->data = data; /* associate! */
  }

  return conn_candidate;
}

/*
 * This function finds the connection in the connection cache that has been
 * unused for the longest time and extracts that from the bundle.
 *
 * Returns the pointer to the connection, or NULL if none was found.
 */
struct connectdata *
Curl_conncache_extract_oldest(struct Curl_easy *data)
{
  struct conncache *connc = data->state.conn_cache;
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;
  timediff_t highscore =- 1;
  timediff_t score;
  struct curltime now;
  struct connectdata *conn_candidate = NULL;
  struct connectbundle *bundle;
  struct connectbundle *bundle_candidate = NULL;

  now = Curl_now();

  CONN_LOCK(data);
  Curl_hash_start_iterate(&connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectdata *conn;

    bundle = he->ptr;

    curr = bundle->conn_list.head;
    while(curr) {
      conn = curr->ptr;

      if(!CONN_INUSE(conn)) {
        /* Set higher score for the age passed since the connection was used */
        score = Curl_timediff(now, conn->now);

        if(score > highscore) {
          highscore = score;
          conn_candidate = conn;
          bundle_candidate = bundle;
        }
      }
      curr = curr->next;
    }

    he = Curl_hash_next_element(&iter);
  }
  if(conn_candidate) {
    /* remove it to prevent another thread from nicking it */
    bundle_remove_conn(bundle_candidate, conn_candidate);
    connc->num_conn--;
    DEBUGF(infof(data, "The cache now contains %zu members\n",
                 connc->num_conn));
    conn_candidate->data = data; /* associate! */
  }
  CONN_UNLOCK(data);

  return conn_candidate;
}

void Curl_conncache_close_all_connections(struct conncache *connc)
{
  struct connectdata *conn;

  conn = Curl_conncache_find_first_connection(connc);
  while(conn) {
    SIGPIPE_VARIABLE(pipe_st);
    conn->data = connc->closure_handle;

    sigpipe_ignore(conn->data, &pipe_st);
    conn->data->easy_conn = NULL; /* clear the easy handle's connection
                                     pointer */
    /* This will remove the connection from the cache */
    connclose(conn, "kill all");
    (void)Curl_disconnect(connc->closure_handle, conn, FALSE);
    sigpipe_restore(&pipe_st);

    conn = Curl_conncache_find_first_connection(connc);
  }

  if(connc->closure_handle) {
    SIGPIPE_VARIABLE(pipe_st);
    sigpipe_ignore(connc->closure_handle, &pipe_st);

    Curl_hostcache_clean(connc->closure_handle,
                         connc->closure_handle->dns.hostcache);
    Curl_close(connc->closure_handle);
    sigpipe_restore(&pipe_st);
  }
}

#if 0
/* Useful for debugging the connection cache */
void Curl_conncache_print(struct conncache *connc)
{
  struct curl_hash_iterator iter;
  struct curl_llist_element *curr;
  struct curl_hash_element *he;

  if(!connc)
    return;

  fprintf(stderr, "=Bundle cache=\n");

  Curl_hash_start_iterate(connc->hash, &iter);

  he = Curl_hash_next_element(&iter);
  while(he) {
    struct connectbundle *bundle;
    struct connectdata *conn;

    bundle = he->ptr;

    fprintf(stderr, "%s -", he->key);
    curr = bundle->conn_list->head;
    while(curr) {
      conn = curr->ptr;

      fprintf(stderr, " [%p %d]", (void *)conn, conn->inuse);
      curr = curr->next;
    }
    fprintf(stderr, "\n");

    he = Curl_hash_next_element(&iter);
  }
}
#endif