net/cor/common.c

   1 /*
   2  *      Connection oriented routing
   3  *      Copyright (C) 2007-2008 Michael Blizek
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      as published by the Free Software Foundation; either version 2
   8  *      of the License, or (at your option) any later version.
   9  *
  10  *      This program is distributed in the hope that it will be useful,
  11  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *      GNU General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License
  16  *      along with this program; if not, write to the Free Software
  17  *      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  *      02110-1301, USA.
  19  */
  20
  21 #include <linux/mutex.h>
  22
  23 #include "cor.h"
  24
  25 DEFINE_MUTEX(cor_bindnodes);
  26 DEFINE_MUTEX(conn_free);
  27
  28 DEFINE_MUTEX(connid_gen);
  29
  30 LIST_HEAD(openports);
  31
  32
  33 struct cell_hdr{
  34         spinlock_t lock;
  35 };
  36
  37 struct kmem_cache *conn_slab;
  38
  39 struct htable connid_table;
  40
  41 struct kmem_cache *bindnode_slab;
  42 struct kmem_cache *connlistener_slab;
  43
  44 void ref_counter_decr(struct ref_counter *cnt)
  45 {
  46         unsigned long iflags;
  47
  48         BUG_ON(0 == cnt);
  49         BUG_ON(0 == cnt->def);
  50
  51         spin_lock_irqsave(&(cnt->lock), iflags);
  52         cnt->refs--;
  53         if (unlikely(cnt->refs == 0)) {
  54                 cnt->def->free(cnt);
  55                 local_irq_restore(iflags);
  56                 return;
  57         }
  58         spin_unlock_irqrestore(&(cnt->lock), iflags);
  59 }
  60
  61 int ref_counter_incr(struct ref_counter *cnt)
  62 {
  63         unsigned long iflags;
  64         int ret = 1;
  65
  66         spin_lock_irqsave(&(cnt->lock), iflags);
  67         ret = 0;
  68         cnt->refs++;
  69         spin_unlock_irqrestore(&(cnt->lock), iflags);
  70
  71         return 0;
  72 }
  73
  74 void ref_counter_init(struct ref_counter *cnt, struct ref_counter_def *def)
  75 {
  76         BUG_ON(0 == cnt);
  77         BUG_ON(0 == def);
  78
  79         spin_lock_init(&(cnt->lock));
  80         cnt->refs = 1;
  81         cnt->def = def;
  82 }
  83
  84
  85 static inline int hdr_size(void)
  86 {
  87         return ((sizeof(struct cell_hdr) + sizeof(void *) - 1) / sizeof(void *)
  88                 ) * sizeof(void *);
  89 }
  90
  91 static inline int elements_per_cell(int cell_size)
  92 {
  93         return (cell_size - hdr_size())/sizeof(void *);
  94 }
  95
  96 static inline struct cell_hdr *cell_addr(struct htable *ht, __u32 id)
  97 {
  98         int idx = (id%ht->htable_size) / (elements_per_cell(ht->cell_size));
  99         return (struct cell_hdr *) (((char *)ht->htable) + ht->cell_size * idx);
 100 }
 101
 102 static inline char **element_addr(struct htable *ht, __u32 id)
 103 {
 104         int idx = (id%ht->htable_size) % (elements_per_cell(ht->cell_size));
 105         return (char **)
 106                         ( ((char *)cell_addr(ht, id)) +
 107                         hdr_size() + idx*sizeof(void *) );
 108 }
 109
 110
 111 static inline char **next_element(struct htable *ht, char *element)
 112 {
 113         return (char **)(element + ht->entry_offset);
 114 }
 115
 116 static inline struct ref_counter *element_refcnt(struct htable *ht, char *element)
 117 {
 118         return (struct ref_counter *)(element + ht->ref_counter_offset);
 119 }
 120
 121
 122 static inline void unlock_element(struct htable *ht, __u32 key)
 123 {
 124         struct cell_hdr *hdr = cell_addr(ht, key);
 125         spin_unlock( &(hdr->lock) );
 126 }
 127
 128
 129 static char **get_element_nounlock(struct htable *ht, __u32 key,
 130                 void *searcheditem)
 131 {
 132         struct cell_hdr *hdr = cell_addr(ht, key);
 133         char **element = element_addr(ht, key);
 134
 135         BUG_ON(0 == element);
 136
 137         spin_lock( &(hdr->lock) );
 138
 139         while (1) {
 140                 if (*element == 0)
 141                         break;
 142                 if (searcheditem != 0 && ht->matches(*element, searcheditem))
 143                         break;
 144                 element = next_element(ht, *element);
 145         }
 146
 147         return element;
 148 }
 149
 150 char *htable_get(struct htable *ht, __u32 key, void *searcheditem)
 151 {
 152         unsigned long iflags;
 153         char *element;
 154
 155         if (ht->htable == 0)
 156                 return 0;
 157
 158         local_irq_save(iflags);
 159         element = *(get_element_nounlock(ht, key, searcheditem));
 160         if (element != 0)
 161                 ref_counter_incr(element_refcnt(ht, element));
 162         unlock_element(ht, key);
 163         local_irq_restore(iflags);
 164
 165         return element;
 166 }
 167
 168 int htable_delete(struct htable *ht, __u32 key,
 169                 void *searcheditem)
 170 {
 171         unsigned long iflags;
 172         char **element;
 173         char **next;
 174         int rc = 0;
 175
 176         if (ht->htable == 0)
 177                 return 1;
 178
 179         local_irq_save(iflags);
 180
 181         element = get_element_nounlock(ht, key, searcheditem);
 182         BUG_ON(0 == element);
 183
 184         if (0 == *element) {
 185                 /* key not in table */
 186                 rc = 1;
 187                 goto out;
 188         }
 189
 190         next = next_element(ht, *element);
 191         ref_counter_decr(element_refcnt(ht, *element));
 192         *element = *next;
 193
 194 out:
 195         unlock_element(ht, key);
 196         local_irq_restore(iflags);
 197
 198         return rc;
 199 }
 200
 201 void htable_insert(struct htable *ht, char *newelement, __u32 key)
 202 {
 203         unsigned long iflags;
 204         char **element;
 205
 206         if (ht->htable == 0)
 207                 return;
 208
 209         BUG_ON(*next_element(ht, newelement) != 0);
 210         local_irq_save(iflags);
 211
 212         element = get_element_nounlock(ht, key, 0);
 213
 214         BUG_ON(element == 0);
 215         BUG_ON(*element != 0);
 216
 217         *element = newelement;
 218         ref_counter_incr(element_refcnt(ht, newelement));
 219
 220         unlock_element(ht, key);
 221         local_irq_restore(iflags);
 222 }
 223
 224
 225 void htable_init(struct htable *ht, int (*matches)(void *htentry,
 226                 void *searcheditem), __u32 entry_offset, __u32 ref_counter_offset)
 227 {
 228         int num_cells;
 229         int j;
 230
 231         BUG_ON(0 == ht);
 232
 233         ht->htable = kmalloc(PAGE_SIZE, GFP_KERNEL);
 234         if (ht->htable == 0) {
 235                 printk(KERN_CRIT "cor: error allocating htable (out of "
 236                                 "memory?)");
 237                 return;
 238         }
 239         memset(ht->htable, 0, PAGE_SIZE);
 240         ht->cell_size = 256;
 241
 242         num_cells = PAGE_SIZE/ht->cell_size;
 243
 244         for (j=0;j<num_cells;j++) {
 245                 struct cell_hdr *hdr = (struct cell_hdr *)
 246                                 ( ((char *) ht->htable) + j * ht->cell_size );
 247                 spin_lock_init(&(hdr->lock));
 248         }
 249
 250         ht->htable_size = num_cells * elements_per_cell(ht->cell_size);
 251         ht->num_elements = 0;
 252
 253         ht->matches = matches;
 254         ht->entry_offset = entry_offset;
 255         ht->ref_counter_offset = ref_counter_offset;
 256 }
 257
 258 struct conn *get_conn(__u32 conn_id)
 259 {
 260         return (struct conn *) htable_get(&connid_table, conn_id, &conn_id);
 261 }
 262
 263 static int connid_alloc(struct conn *sconn)
 264 {
 265         __u32 conn_id;
 266         int i;
 267
 268         BUG_ON(sconn->sourcetype != SOURCE_IN);
 269
 270         mutex_lock(&connid_gen);
 271         for(i=0;i<16;i++) {
 272                 struct conn *tmp;
 273
 274                 conn_id = 0;
 275                 get_random_bytes((char *) &conn_id, sizeof(conn_id));
 276
 277                 if (conn_id == 0)
 278                         continue;
 279
 280                 tmp = get_conn(conn_id);
 281                 if (tmp != 0) {
 282                         ref_counter_decr(&(tmp->refs));
 283                         continue;
 284                 }
 285
 286                 goto found;
 287         }
 288         mutex_unlock(&connid_gen);
 289
 290         return 1;
 291
 292 found:
 293         sconn->source.in.conn_id = conn_id;
 294         htable_insert(&connid_table, (char *) sconn, conn_id);
 295         mutex_unlock(&connid_gen);
 296         return 0;
 297 }
 298
 299 static void free_conn(struct ref_counter *cnt)
 300 {
 301         struct conn *conn = container_of(cnt, struct conn, refs);
 302
 303         BUG_ON(conn->isreset == 0);
 304
 305         mutex_lock(&conn_free);
 306
 307         if (conn->isreset != 3) {
 308                 conn->reversedir->isreset = 3;
 309                 goto out;
 310         }
 311
 312         if (conn->reversedir != 0) {
 313                 conn->reversedir->reversedir = 0;
 314                 free_conn(&(conn->reversedir->refs));
 315                 conn->reversedir = 0;
 316         }
 317
 318         if (conn->sourcetype == SOURCE_IN) {
 319                 ref_counter_decr(&(conn->source.in.nb->refs));
 320                 conn->source.in.nb = 0;
 321         }
 322
 323         if (conn->targettype == TARGET_OUT) {
 324                 ref_counter_decr(&(conn->target.out.nb->refs));
 325                 conn->target.out.nb = 0;
 326         }
 327
 328         databuf_free(&(conn->buf));
 329
 330         kmem_cache_free(conn_slab, conn);
 331
 332 out:
 333         mutex_unlock(&conn_free);
 334 }
 335
 336 static struct ref_counter_def conn_refcnt = {
 337         .free = free_conn
 338 };
 339
 340 /*
 341  * rconn ==> the connection we received the commend from
 342  * ==> init rconn->target.out + rconn->reversedir->source.in
 343  * rc == 0 ==> ok
 344  * rc == 1 ==> connid allocation failed
 345  */
 346 int conn_init_out(struct conn *rconn, struct neighbor *nb)
 347 {
 348         struct conn *sconn = rconn->reversedir;
 349
 350         BUG_ON(TARGET_UNCONNECTED != rconn->targettype);
 351         BUG_ON(0 == sconn);
 352         BUG_ON(SOURCE_NONE != sconn->sourcetype);
 353
 354         memset(&(rconn->target.out), 0, sizeof(rconn->target.out));
 355         memset(&(sconn->source.in), 0, sizeof(sconn->source.in));
 356
 357         rconn->targettype = TARGET_OUT;
 358         sconn->sourcetype = SOURCE_IN;
 359
 360         rconn->target.out.nb = nb;
 361         sconn->source.in.nb = nb;
 362
 363         skb_queue_head_init(&(sconn->source.in.reorder_queue));
 364
 365         /*
 366          * connid_alloc has to be called last, because packets may be received
 367          * immediately after its execution
 368          */
 369         if (connid_alloc(sconn))
 370                 return 1;
 371
 372         mutex_lock(&(nb->conn_list_lock));
 373         list_add_tail(&(sconn->source.in.nb_list), &(nb->rcv_conn_list));
 374         list_add_tail(&(rconn->target.out.nb_list), &(nb->snd_conn_list));
 375         mutex_unlock(&(nb->conn_list_lock));
 376
 377         /* neighbor lists */
 378         ref_counter_incr(&(rconn->refs));
 379         ref_counter_incr(&(sconn->refs));
 380
 381         return 0;
 382 }
 383
 384 void conn_init_sock_source(struct conn *conn)
 385 {
 386         BUG_ON(conn == 0);
 387
 388         conn->sourcetype = SOURCE_SOCK;
 389
 390         memset(&(conn->source.sock), 0, sizeof(conn->source.sock));
 391
 392         init_waitqueue_head(&(conn->source.sock.wait));
 393 }
 394
 395 void conn_init_sock_target(struct conn *conn)
 396 {
 397         BUG_ON(conn == 0);
 398         conn->targettype = TARGET_SOCK;
 399         init_waitqueue_head(&(conn->target.sock.wait));
 400 }
 401
 402 struct conn* alloc_conn(gfp_t allocflags)
 403 {
 404         struct conn *rconn = 0;
 405         struct conn *sconn = 0;
 406
 407         rconn = kmem_cache_alloc(conn_slab, allocflags);
 408         if (unlikely(0 == rconn))
 409                 goto out_err0;
 410
 411         sconn = kmem_cache_alloc(conn_slab, allocflags);
 412         if (unlikely(0 == sconn))
 413                 goto out_err1;
 414
 415         memset(rconn, 0, sizeof(struct conn));
 416         memset(sconn, 0, sizeof(struct conn));
 417
 418         rconn->reversedir = sconn;
 419         sconn->reversedir = rconn;
 420
 421         ref_counter_init(&(rconn->refs), &conn_refcnt);
 422         ref_counter_init(&(sconn->refs), &conn_refcnt);
 423
 424         mutex_init(&(rconn->rcv_lock));
 425         mutex_init(&(sconn->rcv_lock));
 426
 427         rconn->sockstate = SOCKSTATE_CONN;
 428         sconn->sockstate = SOCKSTATE_CONN;
 429
 430         databuf_init(&(rconn->buf));
 431         databuf_init(&(sconn->buf));
 432
 433         return rconn;
 434
 435 out_err1:
 436         kmem_cache_free(conn_slab, rconn);
 437 out_err0:
 438         return 0;
 439 }
 440
 441 static struct connlistener *get_connlistener(__be64 port)
 442 {
 443         struct list_head *curr = openports.next;
 444
 445         while (curr != &openports) {
 446                 struct bindnode *currnode = ((struct bindnode *)
 447                         (((char *)curr) - offsetof(struct bindnode, lh)));
 448                 if (currnode->port == port) {
 449                         BUG_ON(currnode->owner == 0);
 450                         return currnode->owner;
 451                 }
 452
 453                 curr = curr->next;
 454         }
 455
 456         return 0;
 457 }
 458
 459 void close_port(struct connlistener *listener)
 460 {
 461         mutex_lock(&cor_bindnodes);
 462
 463         if (listener->bn != 0) {
 464                 list_del(&(listener->bn->lh));
 465                 kmem_cache_free(bindnode_slab, listener->bn);
 466                 listener->bn = 0;
 467         }
 468
 469         while (list_empty(&(listener->conn_queue)) == 0) {
 470                 struct conn *rconn = container_of(listener->conn_queue.next,
 471                                 struct conn, source.sock.cl_list);
 472                 rconn->reversedir->isreset = 1;
 473                 reset_conn(rconn);
 474                 list_del(&(rconn->source.sock.cl_list));
 475                 ref_counter_decr(&(rconn->refs));
 476         }
 477
 478         kmem_cache_free(connlistener_slab, listener);
 479
 480         mutex_unlock(&cor_bindnodes);
 481 }
 482
 483 struct connlistener *open_port(__be64 port)
 484 {
 485
 486         struct bindnode *bn = 0;
 487         struct connlistener *listener = 0;
 488
 489         mutex_lock(&cor_bindnodes);
 490         if (get_connlistener(port) != 0)
 491                 goto out;
 492
 493
 494         bn = kmem_cache_alloc(bindnode_slab, GFP_KERNEL);
 495         listener = kmem_cache_alloc(connlistener_slab, GFP_KERNEL);
 496
 497         memset(bn, 0, sizeof(struct bindnode));
 498         memset(listener, 0, sizeof(struct connlistener));
 499
 500         bn->owner = listener;
 501         bn->port = port;
 502
 503         /* refcounter is not actually used */
 504         listener->sockstate = SOCKSTATE_LISTENER;
 505         listener->bn = bn;
 506         mutex_init(&(listener->lock));
 507         INIT_LIST_HEAD(&(listener->conn_queue));
 508         init_waitqueue_head(&(listener->wait));
 509
 510         list_add_tail((struct list_head *) &(bn->lh), &openports);
 511
 512 out:
 513         mutex_unlock(&cor_bindnodes);
 514
 515         return listener;
 516 }
 517
 518 /**
 519  * rc == 0 connected
 520  * rc == 2 port not open
 521  * rc == 3 listener queue full
 522  */
 523 int connect_port(struct conn *rconn, __be64 port)
 524 {
 525
 526         struct connlistener *listener;
 527         int rc = 0;
 528
 529         mutex_lock(&cor_bindnodes);
 530
 531         listener = get_connlistener(port);
 532         if (listener == 0) {
 533                 rc = 2;
 534                 goto out;
 535         }
 536
 537         mutex_lock(&(listener->lock));
 538
 539         if (listener->queue_len >= listener->queue_maxlen) {
 540                 if (listener->queue_maxlen <= 0)
 541                         rc = 2;
 542                 else
 543                         rc = 3;
 544
 545                 goto out2;
 546         }
 547
 548         if (ref_counter_incr(&(rconn->reversedir->refs)))
 549                 BUG();
 550
 551         conn_init_sock_target(rconn);
 552         conn_init_sock_source(rconn->reversedir);
 553
 554         list_add_tail(&(rconn->reversedir->source.sock.cl_list),
 555                         &(listener->conn_queue));
 556         listener->queue_len++;
 557         wake_up_interruptible(&(listener->wait));
 558
 559 out2:
 560         mutex_unlock(&(listener->lock));
 561
 562 out:
 563         mutex_unlock(&cor_bindnodes);
 564         return rc;
 565 }
 566
 567 /**
 568  * rc == 0 connected
 569  * rc == 2 addrtype not found
 570  * rc == 3 addr not found
 571  * rc == 4 ==> connid allocation failed
 572  * rc == 5 ==> control msg alloc failed
 573  */
 574 int connect_neigh(struct conn *rconn,
 575                 __u16 addrtypelen, __u8 *addrtype,
 576                 __u16 addrlen, __u8 *addr)
 577 {
 578         int rc = 0;
 579         struct control_msg_out *cm;
 580         struct neighbor *nb = find_neigh(addrtypelen, addrtype, addrlen, addr);
 581         if (nb == 0)
 582                 return 3;
 583         if (conn_init_out(rconn, nb)) {
 584                 rc = 4;
 585                 goto neigh_refcnt;
 586         }
 587
 588         cm = alloc_control_msg();
 589         if (unlikely(cm == 0)) {
 590                 rc = 5;
 591                 goto neigh_refcnt;
 592         }
 593
 594         send_connect_nb(cm, nb, rconn->reversedir->source.in.conn_id);
 595
 596         if (0) {
 597 neigh_refcnt:
 598                 ref_counter_decr(&(nb->refs));
 599         }
 600
 601         return rc;
 602 }
 603
 604 static void _reset_conn(struct conn *conn)
 605 {
 606         if (conn->isreset == 1)
 607                 goto free;
 608
 609         if (conn->isreset == 2 || conn->isreset == 3)
 610                 return;
 611
 612         if (conn->targettype == TARGET_OUT && conn->target.out.conn_id != 0) {
 613                 struct control_msg_out *cm = alloc_control_msg();
 614                 if (likely(cm != 0))
 615                         send_reset_conn(cm, conn->target.out.nb,
 616                                         conn->target.out.conn_id);
 617         }
 618
 619 free:
 620
 621         if (conn->sourcetype == SOURCE_IN) {
 622                 mutex_lock(&(conn->source.in.nb->conn_list_lock));
 623                 list_del(&(conn->source.in.nb_list));
 624                 mutex_unlock(&(conn->source.in.nb->conn_list_lock));
 625
 626                 ref_counter_decr(&(conn->refs));
 627
 628                 if (conn->source.in.conn_id != 0)
 629                         htable_delete(&connid_table, conn->source.in.conn_id,
 630                                         &(conn->source.in.conn_id));
 631         }
 632
 633         if (conn->targettype == TARGET_OUT) {
 634                 mutex_lock(&(conn->target.out.nb->conn_list_lock));
 635                 list_del(&(conn->target.out.nb_list));
 636                 mutex_unlock(&(conn->target.out.nb->conn_list_lock));
 637                 ref_counter_decr(&(conn->refs));
 638         }
 639
 640         conn->isreset = 2;
 641 }
 642
 643 /* warning: do not hold the rcv_lock while calling this! */
 644 void reset_conn(struct conn *conn)
 645 {
 646         _reset_conn(conn);
 647         _reset_conn(conn->reversedir);
 648 }
 649
 650 static int matches_connid_in(void *htentry, void *searcheditem)
 651 {
 652         struct conn *conn = (struct conn *) htentry;
 653         __u32 conn_id = *((__u32 *) searcheditem);
 654         BUG_ON(conn->sourcetype != SOURCE_IN);
 655         return (conn->source.in.conn_id == conn_id);
 656 }
 657
 658 static int __init cor_common_init(void)
 659 {
 660         int rc;
 661
 662         struct conn c;
 663
 664         printk(KERN_ERR "sizeof conn: %d", sizeof(c));
 665         printk(KERN_ERR "  conn.source: %d", sizeof(c.source));
 666         printk(KERN_ERR "  conn.target: %d", sizeof(c.target));
 667         printk(KERN_ERR "  conn.target.out: %d", sizeof(c.target.out));
 668         printk(KERN_ERR "  conn.target.buf: %d", sizeof(c.buf));
 669
 670         printk(KERN_ERR "  mutex: %d", sizeof(struct mutex));
 671         printk(KERN_ERR "  spinlock: %d", sizeof(spinlock_t));
 672         printk(KERN_ERR "  kref: %d", sizeof(struct kref));
 673
 674
 675         conn_slab = kmem_cache_create("cor_conn", sizeof(struct conn), 8, 0, 0);
 676         htable_init(&connid_table, matches_connid_in,
 677                         offsetof(struct conn, source.in.htab_entry),
 678                         offsetof(struct conn, refs));
 679
 680         bindnode_slab = kmem_cache_create("cor_bindnode",
 681                         sizeof(struct bindnode), 8, 0, 0);
 682         connlistener_slab = kmem_cache_create("cor_connlistener",
 683                         sizeof(struct connlistener), 8, 0, 0);
 684
 685         forward_init();
 686
 687         rc = cor_snd_init();
 688         if (rc != 0)
 689                 return rc;
 690
 691         rc = cor_neighbor_init();
 692         if (rc != 0)
 693                 return rc;
 694
 695         rc = cor_rcv_init();
 696         if (rc != 0)
 697                 return rc;
 698
 699         return 0;
 700 }
 701
 702 module_init(cor_common_init);
 703 MODULE_LICENSE("GPL");