1 /*
2 * This file Copyright (C) 2008-2014 Mnemosyne LLC
3 *
4 * It may be used under the GNU GPL versions 2 or 3
5 * or any future license endorsed by Mnemosyne LLC.
6 *
7 */
8
9 #include <string.h> /* strlen() */
10
11 #include <event2/buffer.h>
12 #include <event2/event.h>
13
14 #include "transmission.h"
15 #include "bandwidth.h"
16 #include "cache.h"
17 #include "inout.h" /* tr_ioFindFileLocation() */
18 #include "list.h"
19 #include "peer-mgr.h"
20 #include "torrent.h"
21 #include "trevent.h" /* tr_runInEventThread() */
22 #include "utils.h"
23 #include "web.h"
24 #include "webseed.h"
25
26 struct tr_webseed_task
27 {
28 bool dead;
29 struct evbuffer* content;
30 struct tr_webseed* webseed;
31 tr_session* session;
32 tr_block_index_t block;
33 tr_piece_index_t piece_index;
34 uint32_t piece_offset;
35 uint32_t length;
36 tr_block_index_t blocks_done;
37 uint32_t block_size;
38 struct tr_web_task* web_task;
39 long response_code;
40 };
41
42 struct tr_webseed
43 {
44 tr_peer parent;
45 tr_bandwidth bandwidth;
46 tr_session* session;
47 tr_peer_callback callback;
48 void* callback_data;
49 tr_list* tasks;
50 struct event* timer;
51 char* base_url;
52 size_t base_url_len;
53 int torrent_id;
54 int consecutive_failures;
55 int retry_tickcount;
56 int retry_challenge;
57 int idle_connections;
58 int active_transfers;
59 char** file_urls;
60 };
61
62 enum
63 {
64 TR_IDLE_TIMER_MSEC = 2000,
65 /* */
66 FAILURE_RETRY_INTERVAL = 150,
67 /* */
68 MAX_CONSECUTIVE_FAILURES = 5,
69 /* */
70 MAX_WEBSEED_CONNECTIONS = 4
71 };
72
73 /***
74 ****
75 ***/
76
publish(tr_webseed * w,tr_peer_event * e)77 static void publish(tr_webseed* w, tr_peer_event* e)
78 {
79 if (w->callback != NULL)
80 {
81 (*w->callback)(&w->parent, e, w->callback_data);
82 }
83 }
84
fire_client_got_rejs(tr_torrent * tor,tr_webseed * w,tr_block_index_t block,tr_block_index_t count)85 static void fire_client_got_rejs(tr_torrent* tor, tr_webseed* w, tr_block_index_t block, tr_block_index_t count)
86 {
87 tr_peer_event e = TR_PEER_EVENT_INIT;
88 e.eventType = TR_PEER_CLIENT_GOT_REJ;
89 tr_torrentGetBlockLocation(tor, block, &e.pieceIndex, &e.offset, &e.length);
90
91 for (tr_block_index_t i = 1; i <= count; i++)
92 {
93 if (i == count)
94 {
95 e.length = tr_torBlockCountBytes(tor, block + count - 1);
96 }
97
98 publish(w, &e);
99 e.offset += e.length;
100 }
101 }
102
fire_client_got_blocks(tr_torrent * tor,tr_webseed * w,tr_block_index_t block,tr_block_index_t count)103 static void fire_client_got_blocks(tr_torrent* tor, tr_webseed* w, tr_block_index_t block, tr_block_index_t count)
104 {
105 tr_peer_event e = TR_PEER_EVENT_INIT;
106 e.eventType = TR_PEER_CLIENT_GOT_BLOCK;
107 tr_torrentGetBlockLocation(tor, block, &e.pieceIndex, &e.offset, &e.length);
108
109 for (tr_block_index_t i = 1; i <= count; i++)
110 {
111 if (i == count)
112 {
113 e.length = tr_torBlockCountBytes(tor, block + count - 1);
114 }
115
116 publish(w, &e);
117 e.offset += e.length;
118 }
119 }
120
fire_client_got_piece_data(tr_webseed * w,uint32_t length)121 static void fire_client_got_piece_data(tr_webseed* w, uint32_t length)
122 {
123 tr_peer_event e = TR_PEER_EVENT_INIT;
124 e.eventType = TR_PEER_CLIENT_GOT_PIECE_DATA;
125 e.length = length;
126 publish(w, &e);
127 }
128
129 /***
130 ****
131 ***/
132
133 struct write_block_data
134 {
135 tr_session* session;
136 int torrent_id;
137 struct tr_webseed* webseed;
138 struct evbuffer* content;
139 tr_piece_index_t piece_index;
140 tr_block_index_t block_index;
141 tr_block_index_t count;
142 uint32_t block_offset;
143 };
144
write_block_func(void * vdata)145 static void write_block_func(void* vdata)
146 {
147 struct write_block_data* data = vdata;
148 struct tr_webseed* w = data->webseed;
149 struct evbuffer* buf = data->content;
150 struct tr_torrent* tor;
151
152 tor = tr_torrentFindFromId(data->session, data->torrent_id);
153
154 if (tor != NULL)
155 {
156 uint32_t const block_size = tor->blockSize;
157 uint32_t len = evbuffer_get_length(buf);
158 uint32_t const offset_end = data->block_offset + len;
159 tr_cache* cache = data->session->cache;
160 tr_piece_index_t const piece = data->piece_index;
161
162 if (!tr_torrentPieceIsComplete(tor, piece))
163 {
164 while (len > 0)
165 {
166 uint32_t const bytes_this_pass = MIN(len, block_size);
167 tr_cacheWriteBlock(cache, tor, piece, offset_end - len, bytes_this_pass, buf);
168 len -= bytes_this_pass;
169 }
170
171 fire_client_got_blocks(tor, w, data->block_index, data->count);
172 }
173 }
174
175 evbuffer_free(buf);
176 tr_free(data);
177 }
178
179 /***
180 ****
181 ***/
182
183 struct connection_succeeded_data
184 {
185 struct tr_webseed* webseed;
186 char* real_url;
187 tr_piece_index_t piece_index;
188 uint32_t piece_offset;
189 };
190
connection_succeeded(void * vdata)191 static void connection_succeeded(void* vdata)
192 {
193 struct connection_succeeded_data* data = vdata;
194 struct tr_webseed* w = data->webseed;
195
196 if (++w->active_transfers >= w->retry_challenge && w->retry_challenge != 0)
197 {
198 /* the server seems to be accepting more connections now */
199 w->consecutive_failures = w->retry_tickcount = w->retry_challenge = 0;
200 }
201
202 if (data->real_url != NULL)
203 {
204 tr_torrent* tor = tr_torrentFindFromId(w->session, w->torrent_id);
205
206 if (tor != NULL)
207 {
208 uint64_t file_offset;
209 tr_file_index_t file_index;
210
211 tr_ioFindFileLocation(tor, data->piece_index, data->piece_offset, &file_index, &file_offset);
212 tr_free(w->file_urls[file_index]);
213 w->file_urls[file_index] = data->real_url;
214 data->real_url = NULL;
215 }
216 }
217
218 tr_free(data->real_url);
219 tr_free(data);
220 }
221
222 /***
223 ****
224 ***/
225
on_content_changed(struct evbuffer * buf,struct evbuffer_cb_info const * info,void * vtask)226 static void on_content_changed(struct evbuffer* buf, struct evbuffer_cb_info const* info, void* vtask)
227 {
228 size_t const n_added = info->n_added;
229 struct tr_webseed_task* task = vtask;
230 tr_session* session = task->session;
231
232 tr_sessionLock(session);
233
234 if (!task->dead && n_added > 0)
235 {
236 uint32_t len;
237 struct tr_webseed* w = task->webseed;
238
239 tr_bandwidthUsed(&w->bandwidth, TR_DOWN, n_added, true, tr_time_msec());
240 fire_client_got_piece_data(w, n_added);
241 len = evbuffer_get_length(buf);
242
243 if (task->response_code == 0)
244 {
245 tr_webGetTaskInfo(task->web_task, TR_WEB_GET_CODE, &task->response_code);
246
247 if (task->response_code == 206)
248 {
249 char const* url;
250 struct connection_succeeded_data* data;
251
252 url = NULL;
253 tr_webGetTaskInfo(task->web_task, TR_WEB_GET_REAL_URL, &url);
254
255 data = tr_new(struct connection_succeeded_data, 1);
256 data->webseed = w;
257 data->real_url = tr_strdup(url);
258 data->piece_index = task->piece_index;
259 data->piece_offset = task->piece_offset + task->blocks_done * task->block_size + len - 1;
260
261 /* processing this uses a tr_torrent pointer,
262 so push the work to the libevent thread... */
263 tr_runInEventThread(w->session, connection_succeeded, data);
264 }
265 }
266
267 if (task->response_code == 206 && len >= task->block_size)
268 {
269 /* once we've got at least one full block, save it */
270
271 struct write_block_data* data;
272 uint32_t const block_size = task->block_size;
273 tr_block_index_t const completed = len / block_size;
274
275 data = tr_new(struct write_block_data, 1);
276 data->webseed = task->webseed;
277 data->piece_index = task->piece_index;
278 data->block_index = task->block + task->blocks_done;
279 data->count = completed;
280 data->block_offset = task->piece_offset + task->blocks_done * block_size;
281 data->content = evbuffer_new();
282 data->torrent_id = w->torrent_id;
283 data->session = w->session;
284
285 /* we don't use locking on this evbuffer so we must copy out the data
286 that will be needed when writing the block in a different thread */
287 evbuffer_remove_buffer(task->content, data->content, block_size * completed);
288
289 tr_runInEventThread(w->session, write_block_func, data);
290 task->blocks_done += completed;
291 }
292 }
293
294 tr_sessionUnlock(session);
295 }
296
297 static void task_request_next_chunk(struct tr_webseed_task* task);
298
on_idle(tr_webseed * w)299 static void on_idle(tr_webseed* w)
300 {
301 int want;
302 int running_tasks = tr_list_size(w->tasks);
303 tr_torrent* tor = tr_torrentFindFromId(w->session, w->torrent_id);
304
305 if (w->consecutive_failures >= MAX_CONSECUTIVE_FAILURES)
306 {
307 want = w->idle_connections;
308
309 if (w->retry_tickcount >= FAILURE_RETRY_INTERVAL)
310 {
311 /* some time has passed since our connection attempts failed. try again */
312 ++want;
313 /* if this challenge is fulfilled we will reset consecutive_failures */
314 w->retry_challenge = running_tasks + want;
315 }
316 }
317 else
318 {
319 want = MAX_WEBSEED_CONNECTIONS - running_tasks;
320 w->retry_challenge = running_tasks + w->idle_connections + 1;
321 }
322
323 if (tor != NULL && tor->isRunning && !tr_torrentIsSeed(tor) && want > 0)
324 {
325 int got = 0;
326 tr_block_index_t* blocks = NULL;
327
328 blocks = tr_new(tr_block_index_t, want * 2);
329 tr_peerMgrGetNextRequests(tor, &w->parent, want, blocks, &got, true);
330
331 w->idle_connections -= MIN(w->idle_connections, got);
332
333 if (w->retry_tickcount >= FAILURE_RETRY_INTERVAL && got == want)
334 {
335 w->retry_tickcount = 0;
336 }
337
338 for (int i = 0; i < got; ++i)
339 {
340 tr_block_index_t const b = blocks[i * 2];
341 tr_block_index_t const be = blocks[i * 2 + 1];
342 struct tr_webseed_task* task;
343
344 task = tr_new0(struct tr_webseed_task, 1);
345 task->session = tor->session;
346 task->webseed = w;
347 task->block = b;
348 task->piece_index = tr_torBlockPiece(tor, b);
349 task->piece_offset = tor->blockSize * b - tor->info.pieceSize * task->piece_index;
350 task->length = (be - b) * tor->blockSize + tr_torBlockCountBytes(tor, be);
351 task->blocks_done = 0;
352 task->response_code = 0;
353 task->block_size = tor->blockSize;
354 task->content = evbuffer_new();
355 evbuffer_add_cb(task->content, on_content_changed, task);
356 tr_list_append(&w->tasks, task);
357 task_request_next_chunk(task);
358 }
359
360 tr_free(blocks);
361 }
362 }
363
web_response_func(tr_session * session,bool did_connect UNUSED,bool did_timeout UNUSED,long response_code,void const * response UNUSED,size_t response_byte_count UNUSED,void * vtask)364 static void web_response_func(tr_session* session, bool did_connect UNUSED, bool did_timeout UNUSED, long response_code,
365 void const* response UNUSED, size_t response_byte_count UNUSED, void* vtask)
366 {
367 tr_webseed* w;
368 tr_torrent* tor;
369 struct tr_webseed_task* t = vtask;
370 bool const success = response_code == 206;
371
372 if (t->dead)
373 {
374 evbuffer_free(t->content);
375 tr_free(t);
376 return;
377 }
378
379 w = t->webseed;
380 tor = tr_torrentFindFromId(session, w->torrent_id);
381
382 if (tor != NULL)
383 {
384 /* active_transfers was only increased if the connection was successful */
385 if (t->response_code == 206)
386 {
387 --w->active_transfers;
388 }
389
390 if (!success)
391 {
392 tr_block_index_t const blocks_remain = (t->length + tor->blockSize - 1) / tor->blockSize - t->blocks_done;
393
394 if (blocks_remain != 0)
395 {
396 fire_client_got_rejs(tor, w, t->block + t->blocks_done, blocks_remain);
397 }
398
399 if (t->blocks_done != 0)
400 {
401 ++w->idle_connections;
402 }
403 else if (++w->consecutive_failures >= MAX_CONSECUTIVE_FAILURES && w->retry_tickcount == 0)
404 {
405 /* now wait a while until retrying to establish a connection */
406 ++w->retry_tickcount;
407 }
408
409 tr_list_remove_data(&w->tasks, t);
410 evbuffer_free(t->content);
411 tr_free(t);
412 }
413 else
414 {
415 uint32_t const bytes_done = t->blocks_done * tor->blockSize;
416 uint32_t const buf_len = evbuffer_get_length(t->content);
417
418 if (bytes_done + buf_len < t->length)
419 {
420 /* request finished successfully but there's still data missing. that
421 means we've reached the end of a file and need to request the next one */
422 t->response_code = 0;
423 task_request_next_chunk(t);
424 }
425 else
426 {
427 if (buf_len != 0 && !tr_torrentPieceIsComplete(tor, t->piece_index))
428 {
429 /* on_content_changed() will not write a block if it is smaller than
430 the torrent's block size, i.e. the torrent's very last block */
431 tr_cacheWriteBlock(session->cache, tor, t->piece_index, t->piece_offset + bytes_done, buf_len, t->content);
432
433 fire_client_got_blocks(tor, t->webseed, t->block + t->blocks_done, 1);
434 }
435
436 ++w->idle_connections;
437
438 tr_list_remove_data(&w->tasks, t);
439 evbuffer_free(t->content);
440 tr_free(t);
441
442 on_idle(w);
443 }
444 }
445 }
446 }
447
make_url(tr_webseed * w,tr_file const * file)448 static struct evbuffer* make_url(tr_webseed* w, tr_file const* file)
449 {
450 struct evbuffer* buf = evbuffer_new();
451
452 evbuffer_add(buf, w->base_url, w->base_url_len);
453
454 /* if url ends with a '/', add the torrent name */
455 if (w->base_url[w->base_url_len - 1] == '/' && file->name != NULL)
456 {
457 tr_http_escape(buf, file->name, strlen(file->name), false);
458 }
459
460 return buf;
461 }
462
task_request_next_chunk(struct tr_webseed_task * t)463 static void task_request_next_chunk(struct tr_webseed_task* t)
464 {
465 tr_webseed* w = t->webseed;
466 tr_torrent* tor = tr_torrentFindFromId(w->session, w->torrent_id);
467
468 if (tor != NULL)
469 {
470 char range[64];
471 char** urls = t->webseed->file_urls;
472
473 tr_info const* inf = tr_torrentInfo(tor);
474 uint64_t const remain = t->length - t->blocks_done * tor->blockSize - evbuffer_get_length(t->content);
475
476 uint64_t const total_offset = tr_pieceOffset(tor, t->piece_index, t->piece_offset, t->length - remain);
477 tr_piece_index_t const step_piece = total_offset / inf->pieceSize;
478 uint64_t const step_piece_offset = total_offset - inf->pieceSize * step_piece;
479
480 tr_file_index_t file_index;
481 tr_file const* file;
482 uint64_t file_offset;
483 uint64_t this_pass;
484
485 tr_ioFindFileLocation(tor, step_piece, step_piece_offset, &file_index, &file_offset);
486 file = &inf->files[file_index];
487 this_pass = MIN(remain, file->length - file_offset);
488
489 if (urls[file_index] == NULL)
490 {
491 urls[file_index] = evbuffer_free_to_str(make_url(t->webseed, file), NULL);
492 }
493
494 tr_snprintf(range, sizeof(range), "%" PRIu64 "-%" PRIu64, file_offset, file_offset + this_pass - 1);
495
496 t->web_task = tr_webRunWebseed(tor, urls[file_index], range, web_response_func, t, t->content);
497 }
498 }
499
500 /***
501 ****
502 ***/
503
webseed_timer_func(evutil_socket_t foo UNUSED,short bar UNUSED,void * vw)504 static void webseed_timer_func(evutil_socket_t foo UNUSED, short bar UNUSED, void* vw)
505 {
506 tr_webseed* w = vw;
507
508 if (w->retry_tickcount != 0)
509 {
510 ++w->retry_tickcount;
511 }
512
513 on_idle(w);
514
515 tr_timerAddMsec(w->timer, TR_IDLE_TIMER_MSEC);
516 }
517
518 /***
519 **** tr_peer virtual functions
520 ***/
521
webseed_is_transferring_pieces(tr_peer const * peer,uint64_t now,tr_direction direction,unsigned int * setme_Bps)522 static bool webseed_is_transferring_pieces(tr_peer const* peer, uint64_t now, tr_direction direction, unsigned int* setme_Bps)
523 {
524 unsigned int Bps = 0;
525 bool is_active = false;
526
527 if (direction == TR_DOWN)
528 {
529 tr_webseed const* w = (tr_webseed const*)peer;
530 is_active = w->tasks != NULL;
531 Bps = tr_bandwidthGetPieceSpeed_Bps(&w->bandwidth, now, direction);
532 }
533
534 if (setme_Bps != NULL)
535 {
536 *setme_Bps = Bps;
537 }
538
539 return is_active;
540 }
541
webseed_destruct(tr_peer * peer)542 static void webseed_destruct(tr_peer* peer)
543 {
544 tr_webseed* w = (tr_webseed*)peer;
545
546 /* flag all the pending tasks as dead */
547 for (tr_list* l = w->tasks; l != NULL; l = l->next)
548 {
549 struct tr_webseed_task* task = l->data;
550 task->dead = true;
551 }
552
553 tr_list_free(&w->tasks, NULL);
554
555 /* if we have an array of file URLs, free it */
556 if (w->file_urls != NULL)
557 {
558 tr_torrent* tor = tr_torrentFindFromId(w->session, w->torrent_id);
559 tr_info const* inf = tr_torrentInfo(tor);
560
561 for (tr_file_index_t i = 0; i < inf->fileCount; ++i)
562 {
563 tr_free(w->file_urls[i]);
564 }
565
566 tr_free(w->file_urls);
567 }
568
569 /* webseed destruct */
570 event_free(w->timer);
571 tr_bandwidthDestruct(&w->bandwidth);
572 tr_free(w->base_url);
573
574 /* parent class destruct */
575 tr_peerDestruct(&w->parent);
576 }
577
578 static struct tr_peer_virtual_funcs const my_funcs =
579 {
580 .destruct = webseed_destruct,
581 .is_transferring_pieces = webseed_is_transferring_pieces
582 };
583
584 /***
585 ****
586 ***/
587
tr_webseedNew(struct tr_torrent * tor,char const * url,tr_peer_callback callback,void * callback_data)588 tr_webseed* tr_webseedNew(struct tr_torrent* tor, char const* url, tr_peer_callback callback, void* callback_data)
589 {
590 tr_webseed* w = tr_new0(tr_webseed, 1);
591 tr_peer* peer = &w->parent;
592 tr_info const* inf = tr_torrentInfo(tor);
593
594 /* construct parent class */
595 tr_peerConstruct(peer, tor);
596 peer->client = TR_KEY_webseeds;
597 peer->funcs = &my_funcs;
598 tr_bitfieldSetHasAll(&peer->have);
599 tr_peerUpdateProgress(tor, peer);
600
601 w->torrent_id = tr_torrentId(tor);
602 w->session = tor->session;
603 w->base_url_len = strlen(url);
604 w->base_url = tr_strndup(url, w->base_url_len);
605 w->callback = callback;
606 w->callback_data = callback_data;
607 w->file_urls = tr_new0(char*, inf->fileCount);
608 // tr_rcConstruct(&w->download_rate);
609 tr_bandwidthConstruct(&w->bandwidth, tor->session, &tor->bandwidth);
610 w->timer = evtimer_new(w->session->event_base, webseed_timer_func, w);
611 tr_timerAddMsec(w->timer, TR_IDLE_TIMER_MSEC);
612 return w;
613 }
614