src/vnet/session/segment_manager.c

   1 /*
   2  * Copyright (c) 2017 Cisco and/or its affiliates.
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <vnet/session/segment_manager.h>
  17 #include <vnet/session/session.h>
  18 #include <vnet/session/application.h>
  19
  20 /**
  21  * Counter used to build segment names
  22  */
  23 u32 segment_name_counter = 0;
  24
  25 /**
  26  * Pool of segment managers
  27  */
  28 segment_manager_t *segment_managers = 0;
  29
  30 /**
  31  * Process private segment index
  32  */
  33 u32 *private_segment_indices;
  34
  35 /**
  36  * Default fifo and segment size. TODO config.
  37  */
  38 u32 default_fifo_size = 1 << 16;
  39 u32 default_segment_size = 1 << 20;
  40
  41 void
  42 segment_manager_get_segment_info (u32 index, u8 ** name, u32 * size)
  43 {
  44   svm_fifo_segment_private_t *s;
  45   s = svm_fifo_get_segment (index);
  46   *name = s->h->segment_name;
  47   *size = s->ssvm.ssvm_size;
  48 }
  49
  50 always_inline int
  51 session_manager_add_segment_i (segment_manager_t * sm, u32 segment_size,
  52                                u8 * segment_name)
  53 {
  54   svm_fifo_segment_create_args_t _ca, *ca = &_ca;
  55   int rv;
  56
  57   memset (ca, 0, sizeof (*ca));
  58
  59   ca->segment_name = (char *) segment_name;
  60   ca->segment_size = segment_size;
  61   ca->rx_fifo_size = sm->properties->rx_fifo_size;
  62   ca->tx_fifo_size = sm->properties->tx_fifo_size;
  63   ca->preallocated_fifo_pairs = sm->properties->preallocated_fifo_pairs;
  64
  65   rv = svm_fifo_segment_create (ca);
  66   if (rv)
  67     {
  68       clib_warning ("svm_fifo_segment_create ('%s', %d) failed",
  69                     ca->segment_name, ca->segment_size);
  70       return VNET_API_ERROR_SVM_SEGMENT_CREATE_FAIL;
  71     }
  72
  73   vec_append (sm->segment_indices, ca->new_segment_indices);
  74   vec_free (ca->new_segment_indices);
  75
  76   return 0;
  77 }
  78
  79 int
  80 session_manager_add_segment (segment_manager_t * sm)
  81 {
  82   u8 *segment_name;
  83   svm_fifo_segment_create_args_t _ca, *ca = &_ca;
  84   u32 add_segment_size;
  85   int rv;
  86
  87   memset (ca, 0, sizeof (*ca));
  88   segment_name = format (0, "%d-%d%c", getpid (), segment_name_counter++, 0);
  89   add_segment_size = sm->properties->add_segment_size ?
  90     sm->properties->add_segment_size : default_segment_size;
  91
  92   rv = session_manager_add_segment_i (sm, add_segment_size, segment_name);
  93   vec_free (segment_name);
  94   return rv;
  95 }
  96
  97 int
  98 session_manager_add_first_segment (segment_manager_t * sm, u32 segment_size)
  99 {
 100   u8 *segment_name;
 101   int rv;
 102
 103   segment_name = format (0, "%d-%d%c", getpid (), segment_name_counter++, 0);
 104   rv = session_manager_add_segment_i (sm, segment_size, segment_name);
 105   vec_free (segment_name);
 106   return rv;
 107 }
 108
 109 static void
 110   segment_manager_alloc_process_private_segment
 111   (segment_manager_properties_t * props)
 112 {
 113   svm_fifo_segment_create_args_t _a, *a = &_a;
 114
 115   if (private_segment_indices)
 116     return;
 117
 118   memset (a, 0, sizeof (*a));
 119   a->segment_name = "process-private-segment";
 120   a->segment_size = ~0;
 121   a->rx_fifo_size = props->rx_fifo_size;
 122   a->tx_fifo_size = props->tx_fifo_size;
 123   a->preallocated_fifo_pairs = props->preallocated_fifo_pairs;
 124   a->private_segment_count = props->private_segment_count;
 125   a->private_segment_size = props->private_segment_size;
 126
 127   if (svm_fifo_segment_create_process_private (a))
 128     clib_warning ("Failed to create process private segment");
 129
 130   private_segment_indices = a->new_segment_indices;
 131   ASSERT (vec_len (private_segment_indices));
 132 }
 133
 134 /**
 135  * Initializes segment manager based on options provided.
 136  * Returns error if svm segment allocation fails.
 137  */
 138 int
 139 segment_manager_init (segment_manager_t * sm,
 140                       segment_manager_properties_t * properties,
 141                       u32 first_seg_size)
 142 {
 143   int rv;
 144
 145   /* app allocates these */
 146   sm->properties = properties;
 147
 148   first_seg_size = first_seg_size > 0 ? first_seg_size : default_segment_size;
 149
 150   if (sm->properties->use_private_segment == 0)
 151     {
 152       rv = session_manager_add_first_segment (sm, first_seg_size);
 153       if (rv)
 154         {
 155           clib_warning ("Failed to allocate segment");
 156           return rv;
 157         }
 158     }
 159   else
 160     {
 161       if (vec_len (private_segment_indices) == 0)
 162         segment_manager_alloc_process_private_segment (properties);
 163       ASSERT (vec_len (private_segment_indices));
 164       vec_append (sm->segment_indices, private_segment_indices);
 165     }
 166
 167   clib_spinlock_init (&sm->lockp);
 168   return 0;
 169 }
 170
 171 void
 172 segment_manager_first_segment_maybe_del (segment_manager_t * sm)
 173 {
 174   svm_fifo_segment_private_t *fifo_segment;
 175
 176   /* If the first semgment has no fifos, then delete the 1st segment
 177    */
 178   fifo_segment = svm_fifo_get_segment (sm->segment_indices[0]);
 179   if (!svm_fifo_segment_has_fifos (fifo_segment))
 180     {
 181       clib_spinlock_lock (&sm->lockp);
 182       svm_fifo_segment_delete (fifo_segment);
 183       vec_del1 (sm->segment_indices, 0);
 184       clib_spinlock_unlock (&sm->lockp);
 185     }
 186 }
 187
 188   /**
 189  * Removes segment manager.
 190  *
 191  * Since the fifos allocated in the segment keep backpointers to the sessions
 192  * prior to removing the segment, we call session disconnect. This
 193  * subsequently propages into transport.
 194  */
 195 void
 196 segment_manager_del (segment_manager_t * sm)
 197 {
 198   int j;
 199   svm_fifo_segment_private_t *fifo_segment;
 200   ASSERT (vec_len (sm->segment_indices));
 201
 202   /* Across all fifo segments used by the server */
 203   for (j = 0; j < vec_len (sm->segment_indices); j++)
 204     {
 205       svm_fifo_t *fifo;
 206
 207       /* Vector of fifos allocated in the segment */
 208       fifo_segment = svm_fifo_get_segment (sm->segment_indices[j]);
 209       fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
 210
 211       /*
 212        * Remove any residual sessions from the session lookup table
 213        * Don't bother deleting the individual fifos, we're going to
 214        * throw away the fifo segment in a minute.
 215        */
 216       while (fifo)
 217         {
 218           u32 session_index, thread_index;
 219           stream_session_t *session;
 220
 221           session_index = fifo->master_session_index;
 222           thread_index = fifo->master_thread_index;
 223
 224           session = stream_session_get (session_index, thread_index);
 225
 226           /* Instead of directly removing the session call disconnect */
 227           session_send_session_evt_to_thread (stream_session_handle (session),
 228                                               FIFO_EVENT_DISCONNECT,
 229                                               thread_index);
 230           fifo = fifo->next;
 231         }
 232
 233       /* Instead of removing the segment, test when cleaning up disconnected
 234        * sessions if the segment can be removed.
 235        */
 236     }
 237
 238   segment_manager_first_segment_maybe_del (sm);
 239
 240   clib_spinlock_free (&sm->lockp);
 241   pool_put (segment_managers, sm);
 242 }
 243
 244 static int
 245 segment_manager_notify_app_seg_add (segment_manager_t * sm,
 246                                     u32 fifo_segment_index)
 247 {
 248   application_t *app = application_get (sm->app_index);
 249   u32 seg_size = 0;
 250   u8 *seg_name;
 251
 252   /* Send an API message to the external app, to map new segment */
 253   ASSERT (app->cb_fns.add_segment_callback);
 254
 255   segment_manager_get_segment_info (fifo_segment_index, &seg_name, &seg_size);
 256   return app->cb_fns.add_segment_callback (app->api_client_index, seg_name,
 257                                            seg_size);
 258 }
 259
 260 int
 261 segment_manager_alloc_session_fifos (segment_manager_t * sm,
 262                                      svm_fifo_t ** server_rx_fifo,
 263                                      svm_fifo_t ** server_tx_fifo,
 264                                      u32 * fifo_segment_index)
 265 {
 266   svm_fifo_segment_private_t *fifo_segment;
 267   u32 fifo_size, sm_index;
 268   u8 added_a_segment = 0;
 269   int i;
 270
 271   ASSERT (vec_len (sm->segment_indices));
 272
 273   /* Make sure we don't have multiple threads trying to allocate segments
 274    * at the same time. */
 275   clib_spinlock_lock (&sm->lockp);
 276
 277   /* Allocate svm fifos */
 278 again:
 279   for (i = 0; i < vec_len (sm->segment_indices); i++)
 280     {
 281       *fifo_segment_index = sm->segment_indices[i];
 282       fifo_segment = svm_fifo_get_segment (*fifo_segment_index);
 283
 284       /* FC: cleanup, make sure sm->properties->xxx_fifo_size always set */
 285       fifo_size = sm->properties->rx_fifo_size;
 286       fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
 287       *server_rx_fifo =
 288         svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size,
 289                                      FIFO_SEGMENT_RX_FREELIST);
 290
 291       /* FC: cleanup, make sure sm->properties->xxx_fifo_size always set */
 292       fifo_size = sm->properties->tx_fifo_size;
 293       fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
 294       *server_tx_fifo =
 295         svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size,
 296                                      FIFO_SEGMENT_TX_FREELIST);
 297
 298       if (*server_rx_fifo == 0)
 299         {
 300           /* This would be very odd, but handle it... */
 301           if (*server_tx_fifo != 0)
 302             {
 303               svm_fifo_segment_free_fifo (fifo_segment, *server_tx_fifo,
 304                                           FIFO_SEGMENT_TX_FREELIST);
 305               *server_tx_fifo = 0;
 306             }
 307           continue;
 308         }
 309       if (*server_tx_fifo == 0)
 310         {
 311           if (*server_rx_fifo != 0)
 312             {
 313               svm_fifo_segment_free_fifo (fifo_segment, *server_rx_fifo,
 314                                           FIFO_SEGMENT_RX_FREELIST);
 315               *server_rx_fifo = 0;
 316             }
 317           continue;
 318         }
 319       break;
 320     }
 321
 322   /* See if we're supposed to create another segment */
 323   if (*server_rx_fifo == 0)
 324     {
 325       if (sm->properties->add_segment && !sm->properties->use_private_segment)
 326         {
 327           if (added_a_segment)
 328             {
 329               clib_warning ("added a segment, still cant allocate a fifo");
 330               clib_spinlock_unlock (&sm->lockp);
 331               return SESSION_ERROR_NEW_SEG_NO_SPACE;
 332             }
 333
 334           if (session_manager_add_segment (sm))
 335             {
 336               clib_spinlock_unlock (&sm->lockp);
 337               return VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
 338             }
 339
 340           added_a_segment = 1;
 341           goto again;
 342         }
 343       else
 344         {
 345           clib_warning ("No space to allocate fifos!");
 346           clib_spinlock_unlock (&sm->lockp);
 347           return SESSION_ERROR_NO_SPACE;
 348         }
 349     }
 350
 351   /* Backpointers to segment manager */
 352   sm_index = segment_manager_index (sm);
 353   (*server_tx_fifo)->segment_manager = sm_index;
 354   (*server_rx_fifo)->segment_manager = sm_index;
 355
 356   clib_spinlock_unlock (&sm->lockp);
 357
 358   if (added_a_segment)
 359     return segment_manager_notify_app_seg_add (sm, *fifo_segment_index);
 360
 361   return 0;
 362 }
 363
 364 void
 365 segment_manager_dealloc_fifos (u32 svm_segment_index, svm_fifo_t * rx_fifo,
 366                                svm_fifo_t * tx_fifo)
 367 {
 368   segment_manager_t *sm;
 369   svm_fifo_segment_private_t *fifo_segment;
 370
 371   sm = segment_manager_get_if_valid (rx_fifo->segment_manager);
 372
 373   /* It's possible to have no segment manager if the session was removed
 374    * as result of a detach */
 375   if (!sm)
 376     return;
 377
 378   fifo_segment = svm_fifo_get_segment (svm_segment_index);
 379   svm_fifo_segment_free_fifo (fifo_segment, rx_fifo,
 380                               FIFO_SEGMENT_RX_FREELIST);
 381   svm_fifo_segment_free_fifo (fifo_segment, tx_fifo,
 382                               FIFO_SEGMENT_TX_FREELIST);
 383
 384   /* Don't try to delete process-private segments */
 385   if (sm->properties->private_segment_count > 0)
 386     return;
 387
 388   /* Remove segment only if it holds no fifos and not the first */
 389   if (sm->segment_indices[0] != svm_segment_index
 390       && !svm_fifo_segment_has_fifos (fifo_segment))
 391     {
 392       clib_spinlock_lock (&sm->lockp);
 393       svm_fifo_segment_delete (fifo_segment);
 394       vec_del1 (sm->segment_indices, svm_segment_index);
 395       clib_spinlock_unlock (&sm->lockp);
 396     }
 397 }
 398
 399 /**
 400  * Allocates shm queue in the first segment
 401  */
 402 unix_shared_memory_queue_t *
 403 segment_manager_alloc_queue (segment_manager_t * sm, u32 queue_size)
 404 {
 405   ssvm_shared_header_t *sh;
 406   svm_fifo_segment_private_t *segment;
 407   unix_shared_memory_queue_t *q;
 408   void *oldheap;
 409
 410   ASSERT (sm->segment_indices != 0);
 411
 412   segment = svm_fifo_get_segment (sm->segment_indices[0]);
 413   sh = segment->ssvm.sh;
 414
 415   oldheap = ssvm_push_heap (sh);
 416   q =
 417     unix_shared_memory_queue_init (queue_size, sizeof (session_fifo_event_t),
 418                                    0 /* consumer pid */ , 0
 419                                    /* signal when queue non-empty */ );
 420   ssvm_pop_heap (oldheap);
 421   return q;
 422 }
 423
 424 /**
 425  * Frees shm queue allocated in the first segment
 426  */
 427 void
 428 segment_manager_dealloc_queue (segment_manager_t * sm,
 429                                unix_shared_memory_queue_t * q)
 430 {
 431   ssvm_shared_header_t *sh;
 432   svm_fifo_segment_private_t *segment;
 433   void *oldheap;
 434
 435   ASSERT (sm->segment_indices != 0);
 436
 437   segment = svm_fifo_get_segment (sm->segment_indices[0]);
 438   sh = segment->ssvm.sh;
 439
 440   oldheap = ssvm_push_heap (sh);
 441   unix_shared_memory_queue_free (q);
 442   ssvm_pop_heap (oldheap);
 443 }
 444
 445 /*
 446  * fd.io coding-style-patch-verification: ON
 447  *
 448  * Local Variables:
 449  * eval: (c-set-style "gnu")
 450  * End:
 451  */