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_index = ~0;
  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       vec_free (segment_name);
  71       return VNET_API_ERROR_SVM_SEGMENT_CREATE_FAIL;
  72     }
  73
  74   vec_add1 (sm->segment_indices, ca->new_segment_index);
  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_index != ~0)
 116     return;
 117
 118   memset (a, 0, sizeof (*a));
 119   a->segment_name = "process-private-segment";
 120   a->segment_size = ~0;
 121   a->new_segment_index = ~0;
 122   a->rx_fifo_size = props->rx_fifo_size;
 123   a->tx_fifo_size = props->tx_fifo_size;
 124   a->preallocated_fifo_pairs = props->preallocated_fifo_pairs;
 125
 126   if (svm_fifo_segment_create_process_private (a))
 127     clib_warning ("Failed to create process private segment");
 128
 129   private_segment_index = a->new_segment_index;
 130   ASSERT (private_segment_index != ~0);
 131 }
 132
 133 /**
 134  * Initializes segment manager based on options provided.
 135  * Returns error if svm segment allocation fails.
 136  */
 137 int
 138 segment_manager_init (segment_manager_t * sm,
 139                       segment_manager_properties_t * properties,
 140                       u32 first_seg_size)
 141 {
 142   int rv;
 143
 144   /* app allocates these */
 145   sm->properties = properties;
 146
 147   first_seg_size = first_seg_size > 0 ? first_seg_size : default_segment_size;
 148
 149   if (sm->properties->use_private_segment == 0)
 150     {
 151       rv = session_manager_add_first_segment (sm, first_seg_size);
 152       if (rv)
 153         {
 154           clib_warning ("Failed to allocate segment");
 155           return rv;
 156         }
 157     }
 158   else
 159     {
 160       if (private_segment_index == ~0)
 161         segment_manager_alloc_process_private_segment (properties);
 162       ASSERT (private_segment_index != ~0);
 163       vec_add1 (sm->segment_indices, private_segment_index);
 164     }
 165
 166   clib_spinlock_init (&sm->lockp);
 167   return 0;
 168 }
 169
 170 /**
 171  * Removes segment manager.
 172  *
 173  * Since the fifos allocated in the segment keep backpointers to the sessions
 174  * prior to removing the segment, we call session disconnect. This
 175  * subsequently propages into transport.
 176  */
 177 void
 178 segment_manager_del (segment_manager_t * sm)
 179 {
 180   int j;
 181
 182   /* Across all fifo segments used by the server */
 183   for (j = 0; j < vec_len (sm->segment_indices); j++)
 184     {
 185       svm_fifo_segment_private_t *fifo_segment;
 186       svm_fifo_t *fifo;
 187
 188       /* Vector of fifos allocated in the segment */
 189       fifo_segment = svm_fifo_get_segment (sm->segment_indices[j]);
 190       fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
 191
 192       /*
 193        * Remove any residual sessions from the session lookup table
 194        * Don't bother deleting the individual fifos, we're going to
 195        * throw away the fifo segment in a minute.
 196        */
 197       while (fifo)
 198         {
 199           u32 session_index, thread_index;
 200           stream_session_t *session;
 201
 202           session_index = fifo->master_session_index;
 203           thread_index = fifo->master_thread_index;
 204
 205           session = stream_session_get (session_index, thread_index);
 206
 207           /* Instead of directly removing the session call disconnect */
 208           session_send_session_evt_to_thread (stream_session_handle (session),
 209                                               FIFO_EVENT_DISCONNECT,
 210                                               thread_index);
 211           fifo = fifo->next;
 212         }
 213
 214       /* Instead of removing the segment, test when cleaning up disconnected
 215        * sessions if the segment can be removed.
 216        */
 217     }
 218
 219   clib_spinlock_free (&sm->lockp);
 220   pool_put (segment_managers, sm);
 221 }
 222
 223 static int
 224 segment_manager_notify_app_seg_add (segment_manager_t * sm,
 225                                     u32 fifo_segment_index)
 226 {
 227   application_t *app = application_get (sm->app_index);
 228   u32 seg_size = 0;
 229   u8 *seg_name;
 230
 231   /* Send an API message to the external app, to map new segment */
 232   ASSERT (app->cb_fns.add_segment_callback);
 233
 234   segment_manager_get_segment_info (fifo_segment_index, &seg_name, &seg_size);
 235   return app->cb_fns.add_segment_callback (app->api_client_index, seg_name,
 236                                            seg_size);
 237 }
 238
 239 int
 240 segment_manager_alloc_session_fifos (segment_manager_t * sm,
 241                                      svm_fifo_t ** server_rx_fifo,
 242                                      svm_fifo_t ** server_tx_fifo,
 243                                      u32 * fifo_segment_index)
 244 {
 245   svm_fifo_segment_private_t *fifo_segment;
 246   u32 fifo_size, sm_index;
 247   u8 added_a_segment = 0;
 248   int i;
 249
 250   ASSERT (vec_len (sm->segment_indices));
 251
 252   /* Make sure we don't have multiple threads trying to allocate segments
 253    * at the same time. */
 254   clib_spinlock_lock (&sm->lockp);
 255
 256   /* Allocate svm fifos */
 257 again:
 258   for (i = 0; i < vec_len (sm->segment_indices); i++)
 259     {
 260       *fifo_segment_index = sm->segment_indices[i];
 261       fifo_segment = svm_fifo_get_segment (*fifo_segment_index);
 262
 263       /* FC: cleanup, make sure sm->properties->xxx_fifo_size always set */
 264       fifo_size = sm->properties->rx_fifo_size;
 265       fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
 266       *server_rx_fifo =
 267         svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size,
 268                                      FIFO_SEGMENT_RX_FREELIST);
 269
 270       /* FC: cleanup, make sure sm->properties->xxx_fifo_size always set */
 271       fifo_size = sm->properties->tx_fifo_size;
 272       fifo_size = (fifo_size == 0) ? default_fifo_size : fifo_size;
 273       *server_tx_fifo =
 274         svm_fifo_segment_alloc_fifo (fifo_segment, fifo_size,
 275                                      FIFO_SEGMENT_TX_FREELIST);
 276
 277       if (*server_rx_fifo == 0)
 278         {
 279           /* This would be very odd, but handle it... */
 280           if (*server_tx_fifo != 0)
 281             {
 282               svm_fifo_segment_free_fifo (fifo_segment, *server_tx_fifo,
 283                                           FIFO_SEGMENT_TX_FREELIST);
 284               *server_tx_fifo = 0;
 285             }
 286           continue;
 287         }
 288       if (*server_tx_fifo == 0)
 289         {
 290           if (*server_rx_fifo != 0)
 291             {
 292               svm_fifo_segment_free_fifo (fifo_segment, *server_rx_fifo,
 293                                           FIFO_SEGMENT_RX_FREELIST);
 294               *server_rx_fifo = 0;
 295             }
 296           continue;
 297         }
 298       break;
 299     }
 300
 301   /* See if we're supposed to create another segment */
 302   if (*server_rx_fifo == 0)
 303     {
 304       if (sm->properties->add_segment)
 305         {
 306           if (added_a_segment)
 307             {
 308               clib_warning ("added a segment, still cant allocate a fifo");
 309               clib_spinlock_unlock (&sm->lockp);
 310               return SESSION_ERROR_NEW_SEG_NO_SPACE;
 311             }
 312
 313           if (session_manager_add_segment (sm))
 314             {
 315               clib_spinlock_unlock (&sm->lockp);
 316               return VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
 317             }
 318
 319           added_a_segment = 1;
 320           goto again;
 321         }
 322       else
 323         {
 324           clib_warning ("No space to allocate fifos!");
 325           clib_spinlock_unlock (&sm->lockp);
 326           return SESSION_ERROR_NO_SPACE;
 327         }
 328     }
 329
 330   /* Backpointers to segment manager */
 331   sm_index = segment_manager_index (sm);
 332   (*server_tx_fifo)->segment_manager = sm_index;
 333   (*server_rx_fifo)->segment_manager = sm_index;
 334
 335   clib_spinlock_unlock (&sm->lockp);
 336
 337   if (added_a_segment)
 338     return segment_manager_notify_app_seg_add (sm, *fifo_segment_index);
 339
 340   return 0;
 341 }
 342
 343 void
 344 segment_manager_dealloc_fifos (u32 svm_segment_index, svm_fifo_t * rx_fifo,
 345                                svm_fifo_t * tx_fifo)
 346 {
 347   segment_manager_t *sm;
 348   svm_fifo_segment_private_t *fifo_segment;
 349
 350   sm = segment_manager_get_if_valid (rx_fifo->segment_manager);
 351
 352   /* It's possible to have no segment manager if the session was removed
 353    * as result of a detach */
 354   if (!sm)
 355     return;
 356
 357   fifo_segment = svm_fifo_get_segment (svm_segment_index);
 358   svm_fifo_segment_free_fifo (fifo_segment, rx_fifo,
 359                               FIFO_SEGMENT_RX_FREELIST);
 360   svm_fifo_segment_free_fifo (fifo_segment, tx_fifo,
 361                               FIFO_SEGMENT_TX_FREELIST);
 362
 363   /* Remove segment only if it holds no fifos and not the first */
 364   if (sm->segment_indices[0] != svm_segment_index
 365       && !svm_fifo_segment_has_fifos (fifo_segment))
 366     {
 367       clib_spinlock_lock (&sm->lockp);
 368       svm_fifo_segment_delete (fifo_segment);
 369       vec_del1 (sm->segment_indices, svm_segment_index);
 370       clib_spinlock_unlock (&sm->lockp);
 371     }
 372 }
 373
 374 /**
 375  * Allocates shm queue in the first segment
 376  */
 377 unix_shared_memory_queue_t *
 378 segment_manager_alloc_queue (segment_manager_t * sm, u32 queue_size)
 379 {
 380   ssvm_shared_header_t *sh;
 381   svm_fifo_segment_private_t *segment;
 382   unix_shared_memory_queue_t *q;
 383   void *oldheap;
 384
 385   ASSERT (sm->segment_indices != 0);
 386
 387   segment = svm_fifo_get_segment (sm->segment_indices[0]);
 388   sh = segment->ssvm.sh;
 389
 390   oldheap = ssvm_push_heap (sh);
 391   q =
 392     unix_shared_memory_queue_init (queue_size, sizeof (session_fifo_event_t),
 393                                    0 /* consumer pid */ , 0
 394                                    /* signal when queue non-empty */ );
 395   ssvm_pop_heap (oldheap);
 396   return q;
 397 }
 398
 399 /**
 400  * Frees shm queue allocated in the first segment
 401  */
 402 void
 403 segment_manager_dealloc_queue (segment_manager_t * sm,
 404                                unix_shared_memory_queue_t * q)
 405 {
 406   ssvm_shared_header_t *sh;
 407   svm_fifo_segment_private_t *segment;
 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   unix_shared_memory_queue_free (q);
 417   ssvm_pop_heap (oldheap);
 418 }
 419
 420 /*
 421  * fd.io coding-style-patch-verification: ON
 422  *
 423  * Local Variables:
 424  * eval: (c-set-style "gnu")
 425  * End:
 426  */