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transmission/libtransmission/webseed.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2 (b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <string.h> /* strlen () */
#include <event2/buffer.h>
#include <event2/event.h>
#include "transmission.h"
#include "bandwidth.h"
#include "cache.h"
#include "inout.h" /* tr_ioFindFileLocation () */
#include "list.h"
#include "peer-mgr.h"
#include "torrent.h"
#include "trevent.h" /* tr_runInEventThread () */
#include "utils.h"
#include "web.h"
#include "webseed.h"
struct tr_webseed_task
{
bool dead;
struct evbuffer * content;
struct tr_webseed * webseed;
tr_session * session;
tr_block_index_t block;
tr_piece_index_t piece_index;
uint32_t piece_offset;
uint32_t length;
tr_block_index_t blocks_done;
uint32_t block_size;
struct tr_web_task * web_task;
long response_code;
};
struct tr_webseed
{
tr_peer parent;
tr_bandwidth bandwidth;
tr_session * session;
tr_peer_callback callback;
void * callback_data;
tr_list * tasks;
struct event * timer;
char * base_url;
size_t base_url_len;
int torrent_id;
int consecutive_failures;
int retry_tickcount;
int retry_challenge;
int idle_connections;
int active_transfers;
char ** file_urls;
};
enum
{
TR_IDLE_TIMER_MSEC = 2000,
FAILURE_RETRY_INTERVAL = 150,
MAX_CONSECUTIVE_FAILURES = 5,
MAX_WEBSEED_CONNECTIONS = 4
};
/***
****
***/
static void
publish (tr_webseed * w, tr_peer_event * e)
{
if (w->callback != NULL)
w->callback (&w->parent, e, w->callback_data);
}
static void
fire_client_got_rejs (tr_torrent * tor,
tr_webseed * w,
tr_block_index_t block,
tr_block_index_t count)
{
tr_block_index_t i;
tr_peer_event e = TR_PEER_EVENT_INIT;
e.eventType = TR_PEER_CLIENT_GOT_REJ;
tr_torrentGetBlockLocation (tor, block, &e.pieceIndex, &e.offset, &e.length);
for (i = 1; i <= count; i++)
{
if (i == count)
e.length = tr_torBlockCountBytes (tor, block + count - 1);
publish (w, &e);
e.offset += e.length;
}
}
static void
fire_client_got_blocks (tr_torrent * tor,
tr_webseed * w,
tr_block_index_t block,
tr_block_index_t count)
{
tr_block_index_t i;
tr_peer_event e = TR_PEER_EVENT_INIT;
e.eventType = TR_PEER_CLIENT_GOT_BLOCK;
tr_torrentGetBlockLocation (tor, block, &e.pieceIndex, &e.offset, &e.length);
for (i = 1; i <= count; i++)
{
if (i == count)
e.length = tr_torBlockCountBytes (tor, block + count - 1);
publish (w, &e);
e.offset += e.length;
}
}
static void
fire_client_got_piece_data (tr_webseed * w, uint32_t length)
{
tr_peer_event e = TR_PEER_EVENT_INIT;
e.eventType = TR_PEER_CLIENT_GOT_PIECE_DATA;
e.length = length;
publish (w, &e);
}
/***
****
***/
struct write_block_data
{
tr_session * session;
int torrent_id;
struct tr_webseed * webseed;
struct evbuffer * content;
tr_piece_index_t piece_index;
tr_block_index_t block_index;
tr_block_index_t count;
uint32_t block_offset;
};
static void
write_block_func (void * vdata)
{
struct write_block_data * data = vdata;
struct tr_webseed * w = data->webseed;
struct evbuffer * buf = data->content;
struct tr_torrent * tor;
tor = tr_torrentFindFromId (data->session, data->torrent_id);
if (tor != NULL)
{
const uint32_t block_size = tor->blockSize;
uint32_t len = evbuffer_get_length (buf);
const uint32_t offset_end = data->block_offset + len;
tr_cache * cache = data->session->cache;
const tr_piece_index_t piece = data->piece_index;
while (len > 0)
{
const uint32_t bytes_this_pass = MIN (len, block_size);
tr_cacheWriteBlock (cache, tor, piece, offset_end - len, bytes_this_pass, buf);
len -= bytes_this_pass;
}
fire_client_got_blocks (tor, w, data->block_index, data->count);
}
evbuffer_free (buf);
tr_free (data);
}
/***
****
***/
struct connection_succeeded_data
{
struct tr_webseed * webseed;
char * real_url;
tr_piece_index_t piece_index;
uint32_t piece_offset;
};
static void
connection_succeeded (void * vdata)
{
tr_torrent * tor;
struct connection_succeeded_data * data = vdata;
struct tr_webseed * w = data->webseed;
if (++w->active_transfers >= w->retry_challenge && w->retry_challenge)
/* the server seems to be accepting more connections now */
w->consecutive_failures = w->retry_tickcount = w->retry_challenge = 0;
if (data->real_url && (tor = tr_torrentFindFromId (w->session, w->torrent_id)))
{
uint64_t file_offset;
tr_file_index_t file_index;
tr_ioFindFileLocation (tor, data->piece_index, data->piece_offset,
&file_index, &file_offset);
tr_free (w->file_urls[file_index]);
w->file_urls[file_index] = data->real_url;
data->real_url = NULL;
}
tr_free (data->real_url);
tr_free (data);
}
/***
****
***/
static void
on_content_changed (struct evbuffer * buf,
const struct evbuffer_cb_info * info,
void * vtask)
{
const size_t n_added = info->n_added;
struct tr_webseed_task * task = vtask;
tr_session * session = task->session;
tr_sessionLock (session);
if (!task->dead && (n_added>0))
{
uint32_t len;
struct tr_webseed * w = task->webseed;
tr_bandwidthUsed (&w->bandwidth, TR_DOWN, n_added, true, tr_time_msec ());
fire_client_got_piece_data (w, n_added);
len = evbuffer_get_length (buf);
if (!task->response_code)
{
tr_webGetTaskInfo (task->web_task, TR_WEB_GET_CODE, &task->response_code);
if (task->response_code == 206)
{
const char * url;
struct connection_succeeded_data * data;
url = NULL;
tr_webGetTaskInfo (task->web_task, TR_WEB_GET_REAL_URL, &url);
data = tr_new (struct connection_succeeded_data, 1);
data->webseed = w;
data->real_url = tr_strdup (url);
data->piece_index = task->piece_index;
data->piece_offset = task->piece_offset + (task->blocks_done * task->block_size) + (len - 1);
/* processing this uses a tr_torrent pointer,
so push the work to the libevent thread... */
tr_runInEventThread (w->session, connection_succeeded, data);
}
}
if ((task->response_code == 206) && (len >= task->block_size))
{
/* once we've got at least one full block, save it */
struct write_block_data * data;
const uint32_t block_size = task->block_size;
const tr_block_index_t completed = len / block_size;
data = tr_new (struct write_block_data, 1);
data->webseed = task->webseed;
data->piece_index = task->piece_index;
data->block_index = task->block + task->blocks_done;
data->count = completed;
data->block_offset = task->piece_offset + task->blocks_done * block_size;
data->content = evbuffer_new ();
data->torrent_id = w->torrent_id;
data->session = w->session;
/* we don't use locking on this evbuffer so we must copy out the data
that will be needed when writing the block in a different thread */
evbuffer_remove_buffer (task->content, data->content,
block_size * completed);
tr_runInEventThread (w->session, write_block_func, data);
task->blocks_done += completed;
}
}
tr_sessionUnlock (session);
}
static void task_request_next_chunk (struct tr_webseed_task * task);
static void
on_idle (tr_webseed * w)
{
int want;
int running_tasks = tr_list_size (w->tasks);
tr_torrent * tor = tr_torrentFindFromId (w->session, w->torrent_id);
if (w->consecutive_failures >= MAX_CONSECUTIVE_FAILURES)
{
want = w->idle_connections;
if (w->retry_tickcount >= FAILURE_RETRY_INTERVAL)
{
/* some time has passed since our connection attempts failed. try again */
++want;
/* if this challenge is fulfilled we will reset consecutive_failures */
w->retry_challenge = running_tasks + want;
}
}
else
{
want = MAX_WEBSEED_CONNECTIONS - running_tasks;
w->retry_challenge = running_tasks + w->idle_connections + 1;
}
if (tor && tor->isRunning && !tr_torrentIsSeed (tor) && (want > 0))
{
int i;
int got = 0;
tr_block_index_t * blocks = NULL;
blocks = tr_new (tr_block_index_t, want*2);
tr_peerMgrGetNextRequests (tor, &w->parent, want, blocks, &got, true);
w->idle_connections -= MIN (w->idle_connections, got);
if (w->retry_tickcount >= FAILURE_RETRY_INTERVAL && got == want)
w->retry_tickcount = 0;
for (i=0; i<got; ++i)
{
const tr_block_index_t b = blocks[i*2];
const tr_block_index_t be = blocks[i*2+1];
struct tr_webseed_task * task;
task = tr_new0 (struct tr_webseed_task, 1);
task->session = tor->session;
task->webseed = w;
task->block = b;
task->piece_index = tr_torBlockPiece (tor, b);
task->piece_offset = (tor->blockSize * b) - (tor->info.pieceSize * task->piece_index);
task->length = (be - b) * tor->blockSize + tr_torBlockCountBytes (tor, be);
task->blocks_done = 0;
task->response_code = 0;
task->block_size = tor->blockSize;
task->content = evbuffer_new ();
evbuffer_add_cb (task->content, on_content_changed, task);
tr_list_append (&w->tasks, task);
task_request_next_chunk (task);
}
tr_free (blocks);
}
}
static void
web_response_func (tr_session * session,
bool did_connect UNUSED,
bool did_timeout UNUSED,
long response_code,
const void * response UNUSED,
size_t response_byte_count UNUSED,
void * vtask)
{
tr_webseed * w;
tr_torrent * tor;
struct tr_webseed_task * t = vtask;
const int success = (response_code == 206);
if (t->dead)
{
evbuffer_free (t->content);
tr_free (t);
return;
}
w = t->webseed;
tor = tr_torrentFindFromId (session, w->torrent_id);
if (tor != NULL)
{
/* active_transfers was only increased if the connection was successful */
if (t->response_code == 206)
--w->active_transfers;
if (!success)
{
const tr_block_index_t blocks_remain = (t->length + tor->blockSize - 1)
/ tor->blockSize - t->blocks_done;
if (blocks_remain)
fire_client_got_rejs (tor, w, t->block + t->blocks_done, blocks_remain);
if (t->blocks_done)
++w->idle_connections;
else if (++w->consecutive_failures >= MAX_CONSECUTIVE_FAILURES && !w->retry_tickcount)
/* now wait a while until retrying to establish a connection */
++w->retry_tickcount;
tr_list_remove_data (&w->tasks, t);
evbuffer_free (t->content);
tr_free (t);
}
else
{
const uint32_t bytes_done = t->blocks_done * tor->blockSize;
const uint32_t buf_len = evbuffer_get_length (t->content);
if (bytes_done + buf_len < t->length)
{
/* request finished successfully but there's still data missing. that
means we've reached the end of a file and need to request the next one */
t->response_code = 0;
task_request_next_chunk (t);
}
else
{
if (buf_len)
{
/* on_content_changed () will not write a block if it is smaller than
the torrent's block size, i.e. the torrent's very last block */
tr_cacheWriteBlock (session->cache, tor,
t->piece_index, t->piece_offset + bytes_done,
buf_len, t->content);
fire_client_got_blocks (tor, t->webseed,
t->block + t->blocks_done, 1);
}
++w->idle_connections;
tr_list_remove_data (&w->tasks, t);
evbuffer_free (t->content);
tr_free (t);
on_idle (w);
}
}
}
}
static struct evbuffer *
make_url (tr_webseed * w, const tr_file * file)
{
struct evbuffer * buf = evbuffer_new ();
evbuffer_add (buf, w->base_url, w->base_url_len);
/* if url ends with a '/', add the torrent name */
if (w->base_url[w->base_url_len - 1] == '/' && file->name)
tr_http_escape (buf, file->name, strlen (file->name), false);
return buf;
}
static void
task_request_next_chunk (struct tr_webseed_task * t)
{
tr_webseed * w = t->webseed;
tr_torrent * tor = tr_torrentFindFromId (w->session, w->torrent_id);
if (tor != NULL)
{
char range[64];
char ** urls = t->webseed->file_urls;
const tr_info * inf = tr_torrentInfo (tor);
const uint64_t remain = t->length - t->blocks_done * tor->blockSize
- evbuffer_get_length (t->content);
const uint64_t total_offset = tr_pieceOffset (tor, t->piece_index,
t->piece_offset,
t->length - remain);
const tr_piece_index_t step_piece = total_offset / inf->pieceSize;
const uint64_t step_piece_offset = total_offset - (inf->pieceSize * step_piece);
tr_file_index_t file_index;
const tr_file * file;
uint64_t file_offset;
uint64_t this_pass;
tr_ioFindFileLocation (tor, step_piece, step_piece_offset,
&file_index, &file_offset);
file = &inf->files[file_index];
this_pass = MIN (remain, file->length - file_offset);
if (!urls[file_index])
urls[file_index] = evbuffer_free_to_str (make_url (t->webseed, file));
tr_snprintf (range, sizeof range, "%"PRIu64"-%"PRIu64,
file_offset, file_offset + this_pass - 1);
t->web_task = tr_webRunWebseed (tor, urls[file_index], range,
web_response_func, t, t->content);
}
}
/***
****
***/
static void
webseed_timer_func (evutil_socket_t foo UNUSED, short bar UNUSED, void * vw)
{
tr_webseed * w = vw;
if (w->retry_tickcount)
++w->retry_tickcount;
on_idle (w);
tr_timerAddMsec (w->timer, TR_IDLE_TIMER_MSEC);
}
/***
**** tr_peer virtual functions
***/
static bool
webseed_is_transferring_pieces (const tr_peer * peer,
uint64_t now,
tr_direction direction,
unsigned int * setme_Bps)
{
unsigned int Bps = 0;
bool is_active = false;
if (direction == TR_DOWN)
{
const tr_webseed * w = (const tr_webseed *) peer;
is_active = w->tasks != NULL;
Bps = tr_bandwidthGetPieceSpeed_Bps (&w->bandwidth, now, direction);
}
if (setme_Bps != NULL)
*setme_Bps = Bps;
return is_active;
}
static void
webseed_destruct (tr_peer * peer)
{
tr_list * l;
tr_webseed * w = (tr_webseed *) peer;
/* flag all the pending tasks as dead */
for (l=w->tasks; l!=NULL; l=l->next)
{
struct tr_webseed_task * task = l->data;
task->dead = true;
}
tr_list_free (&w->tasks, NULL);
/* if we have an array of file URLs, free it */
if (w->file_urls != NULL)
{
tr_file_index_t i;
tr_torrent * tor = tr_torrentFindFromId (w->session, w->torrent_id);
const tr_info * inf = tr_torrentInfo (tor);
for (i=0; i<inf->fileCount; ++i)
tr_free (w->file_urls[i]);
tr_free (w->file_urls);
}
/* webseed destruct */
event_free (w->timer);
tr_bandwidthDestruct (&w->bandwidth);
tr_free (w->base_url);
/* parent class destruct */
tr_peerDestruct (&w->parent);
}
static const struct tr_peer_virtual_funcs my_funcs =
{
.destruct = webseed_destruct,
.is_transferring_pieces = webseed_is_transferring_pieces
};
/***
****
***/
tr_webseed*
tr_webseedNew (struct tr_torrent * tor,
const char * url,
tr_peer_callback callback,
void * callback_data)
{
tr_webseed * w = tr_new0 (tr_webseed, 1);
tr_peer * peer = &w->parent;
const tr_info * inf = tr_torrentInfo (tor);
/* construct parent class */
tr_peerConstruct (peer, tor);
peer->client = TR_KEY_webseeds;
peer->funcs = &my_funcs;
tr_bitfieldSetHasAll (&peer->have);
tr_peerUpdateProgress (tor, peer);
w->torrent_id = tr_torrentId (tor);
w->session = tor->session;
w->base_url_len = strlen (url);
w->base_url = tr_strndup (url, w->base_url_len);
w->callback = callback;
w->callback_data = callback_data;
w->file_urls = tr_new0 (char *, inf->fileCount);
//tr_rcConstruct (&w->download_rate);
tr_bandwidthConstruct (&w->bandwidth, tor->session, &tor->bandwidth);
w->timer = evtimer_new (w->session->event_base, webseed_timer_func, w);
tr_timerAddMsec (w->timer, TR_IDLE_TIMER_MSEC);
return w;
}
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