ot_sync.c

   1 /* This software was written by Dirk Engling <erdgeist@erdgeist.org>
   2    It is considered beerware. Prost. Skol. Cheers or whatever.
   3
   4    $id$ */
   5
   6 /* System */
   7 #include <pthread.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <sys/mman.h>
  11 #include <sys/types.h>
  12 #include <sys/uio.h>
  13
  14 /* Libowfat */
  15 #include "byte.h"
  16 #include "io.h"
  17 #include "scan.h"
  18
  19 /* Opentracker */
  20 #include "ot_iovec.h"
  21 #include "ot_mutex.h"
  22 #include "ot_stats.h"
  23 #include "ot_sync.h"
  24 #include "trackerlogic.h"
  25
  26 #ifdef WANT_SYNC_BATCH
  27
  28 #define OT_SYNC_CHUNK_SIZE (512 * 1024)
  29
  30 /* Import Changeset from an external authority
  31    format: d4:syncd[..]ee
  32    [..]:   ( 20:01234567890abcdefghij16:XXXXYYYY )+
  33 */
  34 int add_changeset_to_tracker(uint8_t *data, size_t len) {
  35   ot_hash      *hash;
  36   uint8_t      *end = data + len;
  37   unsigned long peer_count;
  38
  39   /* We do know, that the string is \n terminated, so it cant
  40      overflow */
  41   if (byte_diff(data, 8, "d4:syncd"))
  42     return -1;
  43   data += 8;
  44
  45   while (1) {
  46     if (byte_diff(data, 3, "20:")) {
  47       if (byte_diff(data, 2, "ee"))
  48         return -1;
  49       return 0;
  50     }
  51     data += 3;
  52     hash  = (ot_hash *)data;
  53     data += sizeof(ot_hash);
  54
  55     /* Scan string length indicator */
  56     data += (len = scan_ulong((char *)data, &peer_count));
  57
  58     /* If no long was scanned, it is not divisible by 8, it is not
  59        followed by a colon or claims to need to much memory, we fail */
  60     if (!len || !peer_count || (peer_count & 7) || (*data++ != ':') || (data + peer_count > end))
  61       return -1;
  62
  63     while (peer_count > 0) {
  64       add_peer_to_torrent(hash, (ot_peer *)data, 1);
  65       data       += 8;
  66       peer_count -= 8;
  67     }
  68   }
  69   return 0;
  70 }
  71
  72 /* Proposed output format
  73    d4:syncd20:<info_hash>8*N:(xxxxyyyy)*Nee
  74 */
  75 static void sync_make(int *iovec_entries, struct iovec **iovector) {
  76   int   bucket;
  77   char *r, *re;
  78
  79   /* Setup return vector... */
  80   *iovec_entries = 0;
  81   *iovector      = NULL;
  82   if (!(r = iovec_increase(iovec_entries, iovector, OT_SYNC_CHUNK_SIZE)))
  83     return;
  84
  85   /* ... and pointer to end of current output buffer.
  86      This works as a low watermark */
  87   re = r + OT_SYNC_CHUNK_SIZE;
  88
  89   memmove(r, "d4:syncd", 8);
  90   r += 8;
  91
  92   /* For each bucket... */
  93   for (bucket = 0; bucket < OT_BUCKET_COUNT; ++bucket) {
  94     /* Get exclusive access to that bucket */
  95     ot_vector *torrents_list = mutex_bucket_lock(bucket);
  96     size_t     tor_offset;
  97
  98     /* For each torrent in this bucket.. */
  99     for (tor_offset = 0; tor_offset < torrents_list->size; ++tor_offset) {
 100       /* Address torrents members */
 101       ot_peerlist *peer_list  = (((ot_torrent *)(torrents_list->data))[tor_offset]).peer_list;
 102       ot_hash     *hash       = &(((ot_torrent *)(torrents_list->data))[tor_offset]).hash;
 103       const size_t byte_count = sizeof(ot_peer) * peer_list->changeset.size;
 104
 105       /* If we reached our low watermark in buffer... */
 106       if (re - r <= (ssize_t)(/* strlen( "20:" ) == */ 3 + sizeof(ot_hash) + /* strlen_max( "%zd" ) == */ 12 + byte_count)) {
 107
 108         /* Allocate a fresh output buffer at the end of our buffers list
 109            release bucket and return, if that fails */
 110         if (!(r = iovec_fix_increase_or_free(iovec_entries, iovector, r, OT_SYNC_CHUNK_SIZE)))
 111           return mutex_bucket_unlock(bucket);
 112
 113         /* Adjust new end of output buffer */
 114         re = r + OT_SYNC_CHUNK_SIZE;
 115       }
 116
 117       *r++ = '2';
 118       *r++ = '0';
 119       *r++ = ':';
 120       memmove(r, hash, sizeof(ot_hash));
 121       r += sizeof(ot_hash);
 122       r += sprintf(r, "%zd:", byte_count);
 123       memmove(r, peer_list->changeset.data, byte_count);
 124       r += byte_count;
 125     }
 126
 127     /* All torrents done: release lock on currenct bucket */
 128     mutex_bucket_unlock(bucket);
 129   }
 130
 131   /* Close bencoded sync dictionary */
 132   *r++ = 'e';
 133   *r++ = 'e';
 134
 135   /* Release unused memory in current output buffer */
 136   iovec_fixlast(iovec_entries, iovector, r);
 137 }
 138
 139 /* This is the entry point into this worker thread
 140    It grabs tasks from mutex_tasklist and delivers results back
 141 */
 142 static void *sync_worker(void *args) {
 143   int           iovec_entries;
 144   struct iovec *iovector;
 145
 146   args = args;
 147
 148   while (1) {
 149     ot_tasktype tasktype = TASK_SYNC_OUT;
 150     ot_taskid   taskid   = mutex_workqueue_poptask(&tasktype);
 151     sync_make(&iovec_entries, &iovector);
 152     stats_issue_event(EVENT_SYNC_OUT, FLAG_TCP, iovec_length(&iovec_entries, &iovector));
 153     if (mutex_workqueue_pushresult(taskid, iovec_entries, iovector))
 154       iovec_free(&iovec_entries, &iovector);
 155   }
 156   return NULL;
 157 }
 158
 159 static pthread_t thread_id;
 160 void sync_init( ) {
 161   pthread_create( &thread_id, NULL, sync_worker, NULL );
 162 }
 163
 164 void sync_deinit( ) {
 165   pthread_cancel( thread_id );
 166 }
 167
 168 void sync_deliver( int64 socket ) {
 169   mutex_workqueue_pushtask( socket, TASK_SYNC_OUT );
 170 }
 171
 172 #endif