aboutsummaryrefslogtreecommitdiff
path: root/src/fs/gnunet-service-fs_lc.c
blob: f837ad32040e13ad86312cd846fe6b469938e520 (plain) (blame)
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
/*
     This file is part of GNUnet.
     Copyright (C) 2011 GNUnet e.V.

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/
/**
 * @file fs/gnunet-service-fs_lc.c
 * @brief API to handle 'local clients'
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet-service-fs.h"
#include "gnunet-service-fs_lc.h"
#include "gnunet-service-fs_cp.h"
#include "gnunet-service-fs_pr.h"


/**
 * Doubly-linked list of requests we are performing
 * on behalf of the same client.
 */
struct ClientRequest
{

  /**
   * This is a doubly-linked list.
   */
  struct ClientRequest *next;

  /**
   * This is a doubly-linked list.
   */
  struct ClientRequest *prev;

  /**
   * Request this entry represents.
   */
  struct GSF_PendingRequest *pr;

  /**
   * Client list this request belongs to.
   */
  struct GSF_LocalClient *lc;

  /**
   * Task scheduled to destroy the request.
   */
  struct GNUNET_SCHEDULER_Task * kill_task;

};


/**
 * Replies to be transmitted to the client.  The actual
 * response message is allocated after this struct.
 */
struct ClientResponse
{
  /**
   * This is a doubly-linked list.
   */
  struct ClientResponse *next;

  /**
   * This is a doubly-linked list.
   */
  struct ClientResponse *prev;

  /**
   * Client list entry this response belongs to.
   */
  struct GSF_LocalClient *lc;

  /**
   * Number of bytes in the response.
   */
  size_t msize;
};


/**
 * A local client.
 */
struct GSF_LocalClient
{

  /**
   * We keep clients in a DLL.
   */
  struct GSF_LocalClient *next;

  /**
   * We keep clients in a DLL.
   */
  struct GSF_LocalClient *prev;

  /**
   * ID of the client.
   */
  struct GNUNET_SERVER_Client *client;

  /**
   * Head of list of requests performed on behalf
   * of this client right now.
   */
  struct ClientRequest *cr_head;

  /**
   * Tail of list of requests performed on behalf
   * of this client right now.
   */
  struct ClientRequest *cr_tail;

  /**
   * Head of linked list of responses.
   */
  struct ClientResponse *res_head;

  /**
   * Tail of linked list of responses.
   */
  struct ClientResponse *res_tail;

  /**
   * Context for sending replies.
   */
  struct GNUNET_SERVER_TransmitHandle *th;

};


/**
 * Head of linked list of our local clients.
 */
static struct GSF_LocalClient *client_head;

/**
 * Head of linked list of our local clients.
 */
static struct GSF_LocalClient *client_tail;


/**
 * Look up a local client record or create one if it
 * doesn't exist yet.
 *
 * @param client handle of the client
 * @return handle to local client entry
 */
struct GSF_LocalClient *
GSF_local_client_lookup_ (struct GNUNET_SERVER_Client *client)
{
  struct GSF_LocalClient *pos;

  pos = client_head;
  while ((NULL != pos) && (pos->client != client))
    pos = pos->next;
  if (NULL != pos)
    return pos;
  pos = GNUNET_new (struct GSF_LocalClient);
  pos->client = client;
  GNUNET_CONTAINER_DLL_insert (client_head,
                               client_tail,
                               pos);
  return pos;
}


/**
 * Free the given client request.
 *
 * @param cls the client request to free
 * @param tc task context
 */
static void
client_request_destroy (void *cls,
                        const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct ClientRequest *cr = cls;
  struct GSF_LocalClient *lc;

  cr->kill_task = NULL;
  lc = cr->lc;
  GNUNET_CONTAINER_DLL_remove (lc->cr_head,
                               lc->cr_tail,
                               cr);
  GSF_pending_request_cancel_ (cr->pr,
                               GNUNET_YES);
  GNUNET_STATISTICS_update (GSF_stats,
                            gettext_noop ("# client searches active"),
                            -1,
                            GNUNET_NO);
  GNUNET_free (cr);
}


/**
 * Handle a reply to a pending request.  Also called if a request
 * expires (then with data == NULL).  The handler may be called
 * many times (depending on the request type), but will not be
 * called during or after a call to #GSF_pending_request_cancel()
 * and will also not be called anymore after a call signalling
 * expiration.
 *
 * @param cls user-specified closure
 * @param eval evaluation of the result
 * @param pr handle to the original pending request
 * @param reply_anonymity_level anonymity level for the reply, UINT32_MAX for "unknown"
 * @param expiration when does @a data expire?
 * @param last_transmission when was the last time we've tried to download this block? (FOREVER if unknown)
 * @param type type of the block
 * @param data response data, NULL on request expiration
 * @param data_len number of bytes in @a data
 */
static void
client_response_handler (void *cls,
                         enum GNUNET_BLOCK_EvaluationResult eval,
                         struct GSF_PendingRequest *pr,
                         uint32_t reply_anonymity_level,
                         struct GNUNET_TIME_Absolute expiration,
                         struct GNUNET_TIME_Absolute last_transmission,
                         enum GNUNET_BLOCK_Type type,
                         const void *data,
                         size_t data_len)
{
  struct ClientRequest *cr = cls;
  struct GSF_LocalClient *lc;
  struct ClientPutMessage *pm;
  const struct GSF_PendingRequestData *prd;
  size_t msize;

  if (NULL == data)
  {
    /* local-only request, with no result, clean up. */
    if (NULL == cr->kill_task)
      cr->kill_task = GNUNET_SCHEDULER_add_now (&client_request_destroy,
                                                cr);
    return;
  }
  prd = GSF_pending_request_get_data_ (pr);
  GNUNET_break (type != GNUNET_BLOCK_TYPE_ANY);
  if ((prd->type != type) && (prd->type != GNUNET_BLOCK_TYPE_ANY))
  {
    GNUNET_break (0);
    return;
  }
  GNUNET_STATISTICS_update (GSF_stats,
                            gettext_noop
                            ("# replies received for local clients"), 1,
                            GNUNET_NO);
  GNUNET_assert (pr == cr->pr);
  lc = cr->lc;
  msize = sizeof (struct ClientPutMessage) + data_len;
  {
    char buf[msize] GNUNET_ALIGN;

    pm = (struct ClientPutMessage *) buf;
    pm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_PUT);
    pm->header.size = htons (msize);
    pm->type = htonl (type);
    pm->expiration = GNUNET_TIME_absolute_hton (expiration);
    pm->last_transmission = GNUNET_TIME_absolute_hton (last_transmission);
    pm->num_transmissions = htonl (prd->num_transmissions);
    pm->respect_offered = htonl (prd->respect_offered);
    memcpy (&pm[1], data, data_len);
    GSF_local_client_transmit_ (lc, &pm->header);
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Queued reply to query `%s' for local client\n",
              GNUNET_h2s (&prd->query), (unsigned int) prd->type);
  if (GNUNET_BLOCK_EVALUATION_OK_LAST != eval)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
		"Evaluation %d - keeping query alive\n",
		(int) eval);
    return;
  }
  if (NULL == cr->kill_task)
    cr->kill_task = GNUNET_SCHEDULER_add_now (&client_request_destroy, cr);
}


/**
 * Handle START_SEARCH-message (search request from local client).
 * Only responsible for creating the request entry itself and setting
 * up reply callback and cancellation on client disconnect.  Does NOT
 * execute the actual request strategy (planning).
 *
 * @param client identification of the client
 * @param message the actual message
 * @param prptr where to store the pending request handle for the request
 * @return #GNUNET_YES to start local processing,
 *         #GNUNET_NO to not (yet) start local processing,
 *         #GNUNET_SYSERR on error
 */
int
GSF_local_client_start_search_handler_ (struct GNUNET_SERVER_Client *client,
                                        const struct GNUNET_MessageHeader *message,
                                        struct GSF_PendingRequest **prptr)
{
  static struct GNUNET_PeerIdentity all_zeros;
  const struct SearchMessage *sm;
  struct GSF_LocalClient *lc;
  struct ClientRequest *cr;
  struct GSF_PendingRequestData *prd;
  uint16_t msize;
  unsigned int sc;
  enum GNUNET_BLOCK_Type type;
  enum GSF_PendingRequestOptions options;

  msize = ntohs (message->size);
  if ((msize < sizeof (struct SearchMessage)) ||
      (0 != (msize - sizeof (struct SearchMessage)) % sizeof (struct GNUNET_HashCode)))
  {
    GNUNET_break (0);
    *prptr = NULL;
    return GNUNET_SYSERR;
  }
  GNUNET_STATISTICS_update (GSF_stats,
                            gettext_noop ("# client searches received"),
                            1,
                            GNUNET_NO);
  sc = (msize - sizeof (struct SearchMessage)) / sizeof (struct GNUNET_HashCode);
  sm = (const struct SearchMessage *) message;
  type = ntohl (sm->type);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received request for `%s' of type %u from local client\n",
              GNUNET_h2s (&sm->query), (unsigned int) type);
  lc = GSF_local_client_lookup_ (client);
  cr = NULL;
  /* detect duplicate UBLOCK requests */
  if ((type == GNUNET_BLOCK_TYPE_FS_UBLOCK) ||
      (type == GNUNET_BLOCK_TYPE_ANY))
  {
    cr = lc->cr_head;
    while (NULL != cr)
    {
      prd = GSF_pending_request_get_data_ (cr->pr);
      /* only unify with queries that hae not yet started local processing
	 (SEARCH_MESSAGE_OPTION_CONTINUED was always set) and that have a
	 matching query and type */
      if ((GNUNET_YES != prd->has_started) &&
	  (0 != memcmp (&prd->query,
                        &sm->query,
                        sizeof (struct GNUNET_HashCode))) &&
          (prd->type == type))
        break;
      cr = cr->next;
    }
  }
  if (NULL != cr)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Have existing request, merging content-seen lists.\n");
    GSF_pending_request_update_ (cr->pr,
                                 (const struct GNUNET_HashCode *) &sm[1],
                                 sc);
    GNUNET_STATISTICS_update (GSF_stats,
                              gettext_noop
                              ("# client searches updated (merged content seen list)"),
                              1, GNUNET_NO);
  }
  else
  {
    GNUNET_STATISTICS_update (GSF_stats,
                              gettext_noop ("# client searches active"), 1,
                              GNUNET_NO);
    cr = GNUNET_new (struct ClientRequest);
    cr->lc = lc;
    GNUNET_CONTAINER_DLL_insert (lc->cr_head,
                                 lc->cr_tail,
                                 cr);
    options = GSF_PRO_LOCAL_REQUEST;
    if (0 != (SEARCH_MESSAGE_OPTION_LOOPBACK_ONLY & ntohl (sm->options)))
      options |= GSF_PRO_LOCAL_ONLY;
    cr->pr = GSF_pending_request_create_ (options, type,
					  &sm->query,
                                          (0 !=
                                           memcmp (&sm->target, &all_zeros,
                                                   sizeof (struct GNUNET_PeerIdentity)))
                                          ? &sm->target : NULL, NULL, 0,
                                          0 /* bf */ ,
                                          ntohl (sm->anonymity_level),
                                          0 /* priority */ ,
                                          0 /* ttl */ ,
                                          0 /* sender PID */ ,
                                          0 /* origin PID */ ,
                                          (const struct GNUNET_HashCode *) &sm[1], sc,
                                          &client_response_handler, cr);
  }
  *prptr = cr->pr;
  return (0 !=
          (SEARCH_MESSAGE_OPTION_CONTINUED & ntohl (sm->options))) ? GNUNET_NO :
      GNUNET_YES;
}


/**
 * Transmit the given message by copying it to the target buffer
 * "buf".  "buf" will be NULL and "size" zero if the socket was closed
 * for writing in the meantime.  In that case, do nothing
 * (the disconnect or shutdown handler will take care of the rest).
 * If we were able to transmit messages and there are still more
 * pending, ask core again for further calls to this function.
 *
 * @param cls closure, pointer to the `struct GSF_LocalClient`
 * @param size number of bytes available in @a buf
 * @param buf where the callee should write the message
 * @return number of bytes written to @a buf
 */
static size_t
transmit_to_client (void *cls,
                    size_t size,
                    void *buf)
{
  struct GSF_LocalClient *lc = cls;
  char *cbuf = buf;
  struct ClientResponse *res;
  size_t msize;

  lc->th = NULL;
  if (NULL == buf)
    return 0;
  msize = 0;
  while ((NULL != (res = lc->res_head)) && (res->msize <= size))
  {
    memcpy (&cbuf[msize], &res[1], res->msize);
    msize += res->msize;
    size -= res->msize;
    GNUNET_CONTAINER_DLL_remove (lc->res_head, lc->res_tail, res);
    GNUNET_free (res);
  }
  if (NULL != res)
    lc->th =
        GNUNET_SERVER_notify_transmit_ready (lc->client, res->msize,
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &transmit_to_client, lc);
  return msize;
}


/**
 * Transmit a message to the given local client as soon as possible.
 * If the client disconnects before transmission, the message is
 * simply discarded.
 *
 * @param lc recipient
 * @param msg message to transmit to client
 */
void
GSF_local_client_transmit_ (struct GSF_LocalClient *lc,
                            const struct GNUNET_MessageHeader *msg)
{
  struct ClientResponse *res;
  size_t msize;

  msize = ntohs (msg->size);
  res = GNUNET_malloc (sizeof (struct ClientResponse) + msize);
  res->lc = lc;
  res->msize = msize;
  memcpy (&res[1],
          msg,
          msize);
  GNUNET_CONTAINER_DLL_insert_tail (lc->res_head,
                                    lc->res_tail,
                                    res);
  if (NULL == lc->th)
    lc->th =
        GNUNET_SERVER_notify_transmit_ready (lc->client, msize,
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &transmit_to_client, lc);
}


/**
 * A client disconnected from us.  Tear down the local client
 * record.
 *
 * @param cls unused
 * @param client handle of the client
 */
void
GSF_client_disconnect_handler_ (void *cls,
                                struct GNUNET_SERVER_Client *client)
{
  struct GSF_LocalClient *pos;
  struct ClientRequest *cr;
  struct ClientResponse *res;

  pos = client_head;
  while ((pos != NULL) && (pos->client != client))
    pos = pos->next;
  if (NULL == pos)
    return;
  while (NULL != (cr = pos->cr_head))
  {
    if (NULL != cr->kill_task)
      GNUNET_SCHEDULER_cancel (cr->kill_task);
    client_request_destroy (cr, NULL);
  }
  while (NULL != (res = pos->res_head))
  {
    GNUNET_CONTAINER_DLL_remove (pos->res_head, pos->res_tail, res);
    GNUNET_free (res);
  }
  if (NULL != pos->th)
  {
    GNUNET_SERVER_notify_transmit_ready_cancel (pos->th);
    pos->th = NULL;
  }
  GSF_handle_local_client_disconnect_ (pos);
  GNUNET_CONTAINER_DLL_remove (client_head, client_tail, pos);
  GNUNET_free (pos);
}


/* end of gnunet-service-fs_lc.c */