1 /****************************************************************************** 2 ******************************************************************************* 3 ** 4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 5 ** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved. 6 ** 7 ** This copyrighted material is made available to anyone wishing to use, 8 ** modify, copy, or redistribute it subject to the terms and conditions 9 ** of the GNU General Public License v.2. 10 ** 11 ******************************************************************************* 12 ******************************************************************************/ 13 14 /* 15 * lowcomms.c 16 * 17 * This is the "low-level" comms layer. 18 * 19 * It is responsible for sending/receiving messages 20 * from other nodes in the cluster. 21 * 22 * Cluster nodes are referred to by their nodeids. nodeids are 23 * simply 32 bit numbers to the locking module - if they need to 24 * be expanded for the cluster infrastructure then that is its 25 * responsibility. It is this layer's 26 * responsibility to resolve these into IP address or 27 * whatever it needs for inter-node communication. 28 * 29 * The comms level is two kernel threads that deal mainly with 30 * the receiving of messages from other nodes and passing them 31 * up to the mid-level comms layer (which understands the 32 * message format) for execution by the locking core, and 33 * a send thread which does all the setting up of connections 34 * to remote nodes and the sending of data. Threads are not allowed 35 * to send their own data because it may cause them to wait in times 36 * of high load. Also, this way, the sending thread can collect together 37 * messages bound for one node and send them in one block. 38 * 39 * lowcomms will choose to use either TCP or SCTP as its transport layer 40 * depending on the configuration variable 'protocol'. This should be set 41 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a 42 * cluster-wide mechanism as it must be the same on all nodes of the cluster 43 * for the DLM to function. 44 * 45 */ 46 47 #include <asm/ioctls.h> 48 #include <net/sock.h> 49 #include <net/tcp.h> 50 #include <linux/pagemap.h> 51 #include <linux/file.h> 52 #include <linux/mutex.h> 53 #include <linux/sctp.h> 54 #include <linux/slab.h> 55 #include <net/sctp/sctp.h> 56 #include <net/sctp/user.h> 57 #include <net/ipv6.h> 58 59 #include "dlm_internal.h" 60 #include "lowcomms.h" 61 #include "midcomms.h" 62 #include "config.h" 63 64 #define NEEDED_RMEM (4*1024*1024) 65 #define CONN_HASH_SIZE 32 66 67 /* Number of messages to send before rescheduling */ 68 #define MAX_SEND_MSG_COUNT 25 69 70 struct cbuf { 71 unsigned int base; 72 unsigned int len; 73 unsigned int mask; 74 }; 75 76 static void cbuf_add(struct cbuf *cb, int n) 77 { 78 cb->len += n; 79 } 80 81 static int cbuf_data(struct cbuf *cb) 82 { 83 return ((cb->base + cb->len) & cb->mask); 84 } 85 86 static void cbuf_init(struct cbuf *cb, int size) 87 { 88 cb->base = cb->len = 0; 89 cb->mask = size-1; 90 } 91 92 static void cbuf_eat(struct cbuf *cb, int n) 93 { 94 cb->len -= n; 95 cb->base += n; 96 cb->base &= cb->mask; 97 } 98 99 static bool cbuf_empty(struct cbuf *cb) 100 { 101 return cb->len == 0; 102 } 103 104 struct connection { 105 struct socket *sock; /* NULL if not connected */ 106 uint32_t nodeid; /* So we know who we are in the list */ 107 struct mutex sock_mutex; 108 unsigned long flags; 109 #define CF_READ_PENDING 1 110 #define CF_WRITE_PENDING 2 111 #define CF_CONNECT_PENDING 3 112 #define CF_INIT_PENDING 4 113 #define CF_IS_OTHERCON 5 114 #define CF_CLOSE 6 115 #define CF_APP_LIMITED 7 116 struct list_head writequeue; /* List of outgoing writequeue_entries */ 117 spinlock_t writequeue_lock; 118 int (*rx_action) (struct connection *); /* What to do when active */ 119 void (*connect_action) (struct connection *); /* What to do to connect */ 120 struct page *rx_page; 121 struct cbuf cb; 122 int retries; 123 #define MAX_CONNECT_RETRIES 3 124 int sctp_assoc; 125 struct hlist_node list; 126 struct connection *othercon; 127 struct work_struct rwork; /* Receive workqueue */ 128 struct work_struct swork; /* Send workqueue */ 129 }; 130 #define sock2con(x) ((struct connection *)(x)->sk_user_data) 131 132 /* An entry waiting to be sent */ 133 struct writequeue_entry { 134 struct list_head list; 135 struct page *page; 136 int offset; 137 int len; 138 int end; 139 int users; 140 struct connection *con; 141 }; 142 143 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT]; 144 static int dlm_local_count; 145 146 /* Work queues */ 147 static struct workqueue_struct *recv_workqueue; 148 static struct workqueue_struct *send_workqueue; 149 150 static struct hlist_head connection_hash[CONN_HASH_SIZE]; 151 static DEFINE_MUTEX(connections_lock); 152 static struct kmem_cache *con_cache; 153 154 static void process_recv_sockets(struct work_struct *work); 155 static void process_send_sockets(struct work_struct *work); 156 157 158 /* This is deliberately very simple because most clusters have simple 159 sequential nodeids, so we should be able to go straight to a connection 160 struct in the array */ 161 static inline int nodeid_hash(int nodeid) 162 { 163 return nodeid & (CONN_HASH_SIZE-1); 164 } 165 166 static struct connection *__find_con(int nodeid) 167 { 168 int r; 169 struct hlist_node *h; 170 struct connection *con; 171 172 r = nodeid_hash(nodeid); 173 174 hlist_for_each_entry(con, h, &connection_hash[r], list) { 175 if (con->nodeid == nodeid) 176 return con; 177 } 178 return NULL; 179 } 180 181 /* 182 * If 'allocation' is zero then we don't attempt to create a new 183 * connection structure for this node. 184 */ 185 static struct connection *__nodeid2con(int nodeid, gfp_t alloc) 186 { 187 struct connection *con = NULL; 188 int r; 189 190 con = __find_con(nodeid); 191 if (con || !alloc) 192 return con; 193 194 con = kmem_cache_zalloc(con_cache, alloc); 195 if (!con) 196 return NULL; 197 198 r = nodeid_hash(nodeid); 199 hlist_add_head(&con->list, &connection_hash[r]); 200 201 con->nodeid = nodeid; 202 mutex_init(&con->sock_mutex); 203 INIT_LIST_HEAD(&con->writequeue); 204 spin_lock_init(&con->writequeue_lock); 205 INIT_WORK(&con->swork, process_send_sockets); 206 INIT_WORK(&con->rwork, process_recv_sockets); 207 208 /* Setup action pointers for child sockets */ 209 if (con->nodeid) { 210 struct connection *zerocon = __find_con(0); 211 212 con->connect_action = zerocon->connect_action; 213 if (!con->rx_action) 214 con->rx_action = zerocon->rx_action; 215 } 216 217 return con; 218 } 219 220 /* Loop round all connections */ 221 static void foreach_conn(void (*conn_func)(struct connection *c)) 222 { 223 int i; 224 struct hlist_node *h, *n; 225 struct connection *con; 226 227 for (i = 0; i < CONN_HASH_SIZE; i++) { 228 hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){ 229 conn_func(con); 230 } 231 } 232 } 233 234 static struct connection *nodeid2con(int nodeid, gfp_t allocation) 235 { 236 struct connection *con; 237 238 mutex_lock(&connections_lock); 239 con = __nodeid2con(nodeid, allocation); 240 mutex_unlock(&connections_lock); 241 242 return con; 243 } 244 245 /* This is a bit drastic, but only called when things go wrong */ 246 static struct connection *assoc2con(int assoc_id) 247 { 248 int i; 249 struct hlist_node *h; 250 struct connection *con; 251 252 mutex_lock(&connections_lock); 253 254 for (i = 0 ; i < CONN_HASH_SIZE; i++) { 255 hlist_for_each_entry(con, h, &connection_hash[i], list) { 256 if (con->sctp_assoc == assoc_id) { 257 mutex_unlock(&connections_lock); 258 return con; 259 } 260 } 261 } 262 mutex_unlock(&connections_lock); 263 return NULL; 264 } 265 266 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr) 267 { 268 struct sockaddr_storage addr; 269 int error; 270 271 if (!dlm_local_count) 272 return -1; 273 274 error = dlm_nodeid_to_addr(nodeid, &addr); 275 if (error) 276 return error; 277 278 if (dlm_local_addr[0]->ss_family == AF_INET) { 279 struct sockaddr_in *in4 = (struct sockaddr_in *) &addr; 280 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr; 281 ret4->sin_addr.s_addr = in4->sin_addr.s_addr; 282 } else { 283 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &addr; 284 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr; 285 ret6->sin6_addr = in6->sin6_addr; 286 } 287 288 return 0; 289 } 290 291 /* Data available on socket or listen socket received a connect */ 292 static void lowcomms_data_ready(struct sock *sk, int count_unused) 293 { 294 struct connection *con = sock2con(sk); 295 if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags)) 296 queue_work(recv_workqueue, &con->rwork); 297 } 298 299 static void lowcomms_write_space(struct sock *sk) 300 { 301 struct connection *con = sock2con(sk); 302 303 if (!con) 304 return; 305 306 clear_bit(SOCK_NOSPACE, &con->sock->flags); 307 308 if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) { 309 con->sock->sk->sk_write_pending--; 310 clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags); 311 } 312 313 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) 314 queue_work(send_workqueue, &con->swork); 315 } 316 317 static inline void lowcomms_connect_sock(struct connection *con) 318 { 319 if (test_bit(CF_CLOSE, &con->flags)) 320 return; 321 if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags)) 322 queue_work(send_workqueue, &con->swork); 323 } 324 325 static void lowcomms_state_change(struct sock *sk) 326 { 327 if (sk->sk_state == TCP_ESTABLISHED) 328 lowcomms_write_space(sk); 329 } 330 331 int dlm_lowcomms_connect_node(int nodeid) 332 { 333 struct connection *con; 334 335 /* with sctp there's no connecting without sending */ 336 if (dlm_config.ci_protocol != 0) 337 return 0; 338 339 if (nodeid == dlm_our_nodeid()) 340 return 0; 341 342 con = nodeid2con(nodeid, GFP_NOFS); 343 if (!con) 344 return -ENOMEM; 345 lowcomms_connect_sock(con); 346 return 0; 347 } 348 349 /* Make a socket active */ 350 static int add_sock(struct socket *sock, struct connection *con) 351 { 352 con->sock = sock; 353 354 /* Install a data_ready callback */ 355 con->sock->sk->sk_data_ready = lowcomms_data_ready; 356 con->sock->sk->sk_write_space = lowcomms_write_space; 357 con->sock->sk->sk_state_change = lowcomms_state_change; 358 con->sock->sk->sk_user_data = con; 359 con->sock->sk->sk_allocation = GFP_NOFS; 360 return 0; 361 } 362 363 /* Add the port number to an IPv6 or 4 sockaddr and return the address 364 length */ 365 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port, 366 int *addr_len) 367 { 368 saddr->ss_family = dlm_local_addr[0]->ss_family; 369 if (saddr->ss_family == AF_INET) { 370 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr; 371 in4_addr->sin_port = cpu_to_be16(port); 372 *addr_len = sizeof(struct sockaddr_in); 373 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero)); 374 } else { 375 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr; 376 in6_addr->sin6_port = cpu_to_be16(port); 377 *addr_len = sizeof(struct sockaddr_in6); 378 } 379 memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len); 380 } 381 382 /* Close a remote connection and tidy up */ 383 static void close_connection(struct connection *con, bool and_other) 384 { 385 mutex_lock(&con->sock_mutex); 386 387 if (con->sock) { 388 sock_release(con->sock); 389 con->sock = NULL; 390 } 391 if (con->othercon && and_other) { 392 /* Will only re-enter once. */ 393 close_connection(con->othercon, false); 394 } 395 if (con->rx_page) { 396 __free_page(con->rx_page); 397 con->rx_page = NULL; 398 } 399 400 con->retries = 0; 401 mutex_unlock(&con->sock_mutex); 402 } 403 404 /* We only send shutdown messages to nodes that are not part of the cluster */ 405 static void sctp_send_shutdown(sctp_assoc_t associd) 406 { 407 static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; 408 struct msghdr outmessage; 409 struct cmsghdr *cmsg; 410 struct sctp_sndrcvinfo *sinfo; 411 int ret; 412 struct connection *con; 413 414 con = nodeid2con(0,0); 415 BUG_ON(con == NULL); 416 417 outmessage.msg_name = NULL; 418 outmessage.msg_namelen = 0; 419 outmessage.msg_control = outcmsg; 420 outmessage.msg_controllen = sizeof(outcmsg); 421 outmessage.msg_flags = MSG_EOR; 422 423 cmsg = CMSG_FIRSTHDR(&outmessage); 424 cmsg->cmsg_level = IPPROTO_SCTP; 425 cmsg->cmsg_type = SCTP_SNDRCV; 426 cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo)); 427 outmessage.msg_controllen = cmsg->cmsg_len; 428 sinfo = CMSG_DATA(cmsg); 429 memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo)); 430 431 sinfo->sinfo_flags |= MSG_EOF; 432 sinfo->sinfo_assoc_id = associd; 433 434 ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0); 435 436 if (ret != 0) 437 log_print("send EOF to node failed: %d", ret); 438 } 439 440 static void sctp_init_failed_foreach(struct connection *con) 441 { 442 con->sctp_assoc = 0; 443 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) { 444 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) 445 queue_work(send_workqueue, &con->swork); 446 } 447 } 448 449 /* INIT failed but we don't know which node... 450 restart INIT on all pending nodes */ 451 static void sctp_init_failed(void) 452 { 453 mutex_lock(&connections_lock); 454 455 foreach_conn(sctp_init_failed_foreach); 456 457 mutex_unlock(&connections_lock); 458 } 459 460 /* Something happened to an association */ 461 static void process_sctp_notification(struct connection *con, 462 struct msghdr *msg, char *buf) 463 { 464 union sctp_notification *sn = (union sctp_notification *)buf; 465 466 if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) { 467 switch (sn->sn_assoc_change.sac_state) { 468 469 case SCTP_COMM_UP: 470 case SCTP_RESTART: 471 { 472 /* Check that the new node is in the lockspace */ 473 struct sctp_prim prim; 474 int nodeid; 475 int prim_len, ret; 476 int addr_len; 477 struct connection *new_con; 478 479 /* 480 * We get this before any data for an association. 481 * We verify that the node is in the cluster and 482 * then peel off a socket for it. 483 */ 484 if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) { 485 log_print("COMM_UP for invalid assoc ID %d", 486 (int)sn->sn_assoc_change.sac_assoc_id); 487 sctp_init_failed(); 488 return; 489 } 490 memset(&prim, 0, sizeof(struct sctp_prim)); 491 prim_len = sizeof(struct sctp_prim); 492 prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id; 493 494 ret = kernel_getsockopt(con->sock, 495 IPPROTO_SCTP, 496 SCTP_PRIMARY_ADDR, 497 (char*)&prim, 498 &prim_len); 499 if (ret < 0) { 500 log_print("getsockopt/sctp_primary_addr on " 501 "new assoc %d failed : %d", 502 (int)sn->sn_assoc_change.sac_assoc_id, 503 ret); 504 505 /* Retry INIT later */ 506 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id); 507 if (new_con) 508 clear_bit(CF_CONNECT_PENDING, &con->flags); 509 return; 510 } 511 make_sockaddr(&prim.ssp_addr, 0, &addr_len); 512 if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) { 513 unsigned char *b=(unsigned char *)&prim.ssp_addr; 514 log_print("reject connect from unknown addr"); 515 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 516 b, sizeof(struct sockaddr_storage)); 517 sctp_send_shutdown(prim.ssp_assoc_id); 518 return; 519 } 520 521 new_con = nodeid2con(nodeid, GFP_NOFS); 522 if (!new_con) 523 return; 524 525 /* Peel off a new sock */ 526 sctp_lock_sock(con->sock->sk); 527 ret = sctp_do_peeloff(con->sock->sk, 528 sn->sn_assoc_change.sac_assoc_id, 529 &new_con->sock); 530 sctp_release_sock(con->sock->sk); 531 if (ret < 0) { 532 log_print("Can't peel off a socket for " 533 "connection %d to node %d: err=%d", 534 (int)sn->sn_assoc_change.sac_assoc_id, 535 nodeid, ret); 536 return; 537 } 538 add_sock(new_con->sock, new_con); 539 540 log_print("connecting to %d sctp association %d", 541 nodeid, (int)sn->sn_assoc_change.sac_assoc_id); 542 543 /* Send any pending writes */ 544 clear_bit(CF_CONNECT_PENDING, &new_con->flags); 545 clear_bit(CF_INIT_PENDING, &con->flags); 546 if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) { 547 queue_work(send_workqueue, &new_con->swork); 548 } 549 if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags)) 550 queue_work(recv_workqueue, &new_con->rwork); 551 } 552 break; 553 554 case SCTP_COMM_LOST: 555 case SCTP_SHUTDOWN_COMP: 556 { 557 con = assoc2con(sn->sn_assoc_change.sac_assoc_id); 558 if (con) { 559 con->sctp_assoc = 0; 560 } 561 } 562 break; 563 564 /* We don't know which INIT failed, so clear the PENDING flags 565 * on them all. if assoc_id is zero then it will then try 566 * again */ 567 568 case SCTP_CANT_STR_ASSOC: 569 { 570 log_print("Can't start SCTP association - retrying"); 571 sctp_init_failed(); 572 } 573 break; 574 575 default: 576 log_print("unexpected SCTP assoc change id=%d state=%d", 577 (int)sn->sn_assoc_change.sac_assoc_id, 578 sn->sn_assoc_change.sac_state); 579 } 580 } 581 } 582 583 /* Data received from remote end */ 584 static int receive_from_sock(struct connection *con) 585 { 586 int ret = 0; 587 struct msghdr msg = {}; 588 struct kvec iov[2]; 589 unsigned len; 590 int r; 591 int call_again_soon = 0; 592 int nvec; 593 char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; 594 595 mutex_lock(&con->sock_mutex); 596 597 if (con->sock == NULL) { 598 ret = -EAGAIN; 599 goto out_close; 600 } 601 602 if (con->rx_page == NULL) { 603 /* 604 * This doesn't need to be atomic, but I think it should 605 * improve performance if it is. 606 */ 607 con->rx_page = alloc_page(GFP_ATOMIC); 608 if (con->rx_page == NULL) 609 goto out_resched; 610 cbuf_init(&con->cb, PAGE_CACHE_SIZE); 611 } 612 613 /* Only SCTP needs these really */ 614 memset(&incmsg, 0, sizeof(incmsg)); 615 msg.msg_control = incmsg; 616 msg.msg_controllen = sizeof(incmsg); 617 618 /* 619 * iov[0] is the bit of the circular buffer between the current end 620 * point (cb.base + cb.len) and the end of the buffer. 621 */ 622 iov[0].iov_len = con->cb.base - cbuf_data(&con->cb); 623 iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb); 624 iov[1].iov_len = 0; 625 nvec = 1; 626 627 /* 628 * iov[1] is the bit of the circular buffer between the start of the 629 * buffer and the start of the currently used section (cb.base) 630 */ 631 if (cbuf_data(&con->cb) >= con->cb.base) { 632 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb); 633 iov[1].iov_len = con->cb.base; 634 iov[1].iov_base = page_address(con->rx_page); 635 nvec = 2; 636 } 637 len = iov[0].iov_len + iov[1].iov_len; 638 639 r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len, 640 MSG_DONTWAIT | MSG_NOSIGNAL); 641 if (ret <= 0) 642 goto out_close; 643 644 /* Process SCTP notifications */ 645 if (msg.msg_flags & MSG_NOTIFICATION) { 646 msg.msg_control = incmsg; 647 msg.msg_controllen = sizeof(incmsg); 648 649 process_sctp_notification(con, &msg, 650 page_address(con->rx_page) + con->cb.base); 651 mutex_unlock(&con->sock_mutex); 652 return 0; 653 } 654 BUG_ON(con->nodeid == 0); 655 656 if (ret == len) 657 call_again_soon = 1; 658 cbuf_add(&con->cb, ret); 659 ret = dlm_process_incoming_buffer(con->nodeid, 660 page_address(con->rx_page), 661 con->cb.base, con->cb.len, 662 PAGE_CACHE_SIZE); 663 if (ret == -EBADMSG) { 664 log_print("lowcomms: addr=%p, base=%u, len=%u, " 665 "iov_len=%u, iov_base[0]=%p, read=%d", 666 page_address(con->rx_page), con->cb.base, con->cb.len, 667 len, iov[0].iov_base, r); 668 } 669 if (ret < 0) 670 goto out_close; 671 cbuf_eat(&con->cb, ret); 672 673 if (cbuf_empty(&con->cb) && !call_again_soon) { 674 __free_page(con->rx_page); 675 con->rx_page = NULL; 676 } 677 678 if (call_again_soon) 679 goto out_resched; 680 mutex_unlock(&con->sock_mutex); 681 return 0; 682 683 out_resched: 684 if (!test_and_set_bit(CF_READ_PENDING, &con->flags)) 685 queue_work(recv_workqueue, &con->rwork); 686 mutex_unlock(&con->sock_mutex); 687 return -EAGAIN; 688 689 out_close: 690 mutex_unlock(&con->sock_mutex); 691 if (ret != -EAGAIN) { 692 close_connection(con, false); 693 /* Reconnect when there is something to send */ 694 } 695 /* Don't return success if we really got EOF */ 696 if (ret == 0) 697 ret = -EAGAIN; 698 699 return ret; 700 } 701 702 /* Listening socket is busy, accept a connection */ 703 static int tcp_accept_from_sock(struct connection *con) 704 { 705 int result; 706 struct sockaddr_storage peeraddr; 707 struct socket *newsock; 708 int len; 709 int nodeid; 710 struct connection *newcon; 711 struct connection *addcon; 712 713 memset(&peeraddr, 0, sizeof(peeraddr)); 714 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, 715 IPPROTO_TCP, &newsock); 716 if (result < 0) 717 return -ENOMEM; 718 719 mutex_lock_nested(&con->sock_mutex, 0); 720 721 result = -ENOTCONN; 722 if (con->sock == NULL) 723 goto accept_err; 724 725 newsock->type = con->sock->type; 726 newsock->ops = con->sock->ops; 727 728 result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK); 729 if (result < 0) 730 goto accept_err; 731 732 /* Get the connected socket's peer */ 733 memset(&peeraddr, 0, sizeof(peeraddr)); 734 if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 735 &len, 2)) { 736 result = -ECONNABORTED; 737 goto accept_err; 738 } 739 740 /* Get the new node's NODEID */ 741 make_sockaddr(&peeraddr, 0, &len); 742 if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) { 743 unsigned char *b=(unsigned char *)&peeraddr; 744 log_print("connect from non cluster node"); 745 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 746 b, sizeof(struct sockaddr_storage)); 747 sock_release(newsock); 748 mutex_unlock(&con->sock_mutex); 749 return -1; 750 } 751 752 log_print("got connection from %d", nodeid); 753 754 /* Check to see if we already have a connection to this node. This 755 * could happen if the two nodes initiate a connection at roughly 756 * the same time and the connections cross on the wire. 757 * In this case we store the incoming one in "othercon" 758 */ 759 newcon = nodeid2con(nodeid, GFP_NOFS); 760 if (!newcon) { 761 result = -ENOMEM; 762 goto accept_err; 763 } 764 mutex_lock_nested(&newcon->sock_mutex, 1); 765 if (newcon->sock) { 766 struct connection *othercon = newcon->othercon; 767 768 if (!othercon) { 769 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS); 770 if (!othercon) { 771 log_print("failed to allocate incoming socket"); 772 mutex_unlock(&newcon->sock_mutex); 773 result = -ENOMEM; 774 goto accept_err; 775 } 776 othercon->nodeid = nodeid; 777 othercon->rx_action = receive_from_sock; 778 mutex_init(&othercon->sock_mutex); 779 INIT_WORK(&othercon->swork, process_send_sockets); 780 INIT_WORK(&othercon->rwork, process_recv_sockets); 781 set_bit(CF_IS_OTHERCON, &othercon->flags); 782 } 783 if (!othercon->sock) { 784 newcon->othercon = othercon; 785 othercon->sock = newsock; 786 newsock->sk->sk_user_data = othercon; 787 add_sock(newsock, othercon); 788 addcon = othercon; 789 } 790 else { 791 printk("Extra connection from node %d attempted\n", nodeid); 792 result = -EAGAIN; 793 mutex_unlock(&newcon->sock_mutex); 794 goto accept_err; 795 } 796 } 797 else { 798 newsock->sk->sk_user_data = newcon; 799 newcon->rx_action = receive_from_sock; 800 add_sock(newsock, newcon); 801 addcon = newcon; 802 } 803 804 mutex_unlock(&newcon->sock_mutex); 805 806 /* 807 * Add it to the active queue in case we got data 808 * between processing the accept adding the socket 809 * to the read_sockets list 810 */ 811 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags)) 812 queue_work(recv_workqueue, &addcon->rwork); 813 mutex_unlock(&con->sock_mutex); 814 815 return 0; 816 817 accept_err: 818 mutex_unlock(&con->sock_mutex); 819 sock_release(newsock); 820 821 if (result != -EAGAIN) 822 log_print("error accepting connection from node: %d", result); 823 return result; 824 } 825 826 static void free_entry(struct writequeue_entry *e) 827 { 828 __free_page(e->page); 829 kfree(e); 830 } 831 832 /* Initiate an SCTP association. 833 This is a special case of send_to_sock() in that we don't yet have a 834 peeled-off socket for this association, so we use the listening socket 835 and add the primary IP address of the remote node. 836 */ 837 static void sctp_init_assoc(struct connection *con) 838 { 839 struct sockaddr_storage rem_addr; 840 char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; 841 struct msghdr outmessage; 842 struct cmsghdr *cmsg; 843 struct sctp_sndrcvinfo *sinfo; 844 struct connection *base_con; 845 struct writequeue_entry *e; 846 int len, offset; 847 int ret; 848 int addrlen; 849 struct kvec iov[1]; 850 851 if (test_and_set_bit(CF_INIT_PENDING, &con->flags)) 852 return; 853 854 if (con->retries++ > MAX_CONNECT_RETRIES) 855 return; 856 857 if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) { 858 log_print("no address for nodeid %d", con->nodeid); 859 return; 860 } 861 base_con = nodeid2con(0, 0); 862 BUG_ON(base_con == NULL); 863 864 make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen); 865 866 outmessage.msg_name = &rem_addr; 867 outmessage.msg_namelen = addrlen; 868 outmessage.msg_control = outcmsg; 869 outmessage.msg_controllen = sizeof(outcmsg); 870 outmessage.msg_flags = MSG_EOR; 871 872 spin_lock(&con->writequeue_lock); 873 874 if (list_empty(&con->writequeue)) { 875 spin_unlock(&con->writequeue_lock); 876 log_print("writequeue empty for nodeid %d", con->nodeid); 877 return; 878 } 879 880 e = list_first_entry(&con->writequeue, struct writequeue_entry, list); 881 len = e->len; 882 offset = e->offset; 883 spin_unlock(&con->writequeue_lock); 884 885 /* Send the first block off the write queue */ 886 iov[0].iov_base = page_address(e->page)+offset; 887 iov[0].iov_len = len; 888 889 cmsg = CMSG_FIRSTHDR(&outmessage); 890 cmsg->cmsg_level = IPPROTO_SCTP; 891 cmsg->cmsg_type = SCTP_SNDRCV; 892 cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo)); 893 sinfo = CMSG_DATA(cmsg); 894 memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo)); 895 sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid()); 896 outmessage.msg_controllen = cmsg->cmsg_len; 897 898 ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len); 899 if (ret < 0) { 900 log_print("Send first packet to node %d failed: %d", 901 con->nodeid, ret); 902 903 /* Try again later */ 904 clear_bit(CF_CONNECT_PENDING, &con->flags); 905 clear_bit(CF_INIT_PENDING, &con->flags); 906 } 907 else { 908 spin_lock(&con->writequeue_lock); 909 e->offset += ret; 910 e->len -= ret; 911 912 if (e->len == 0 && e->users == 0) { 913 list_del(&e->list); 914 free_entry(e); 915 } 916 spin_unlock(&con->writequeue_lock); 917 } 918 } 919 920 /* Connect a new socket to its peer */ 921 static void tcp_connect_to_sock(struct connection *con) 922 { 923 int result = -EHOSTUNREACH; 924 struct sockaddr_storage saddr, src_addr; 925 int addr_len; 926 struct socket *sock = NULL; 927 int one = 1; 928 929 if (con->nodeid == 0) { 930 log_print("attempt to connect sock 0 foiled"); 931 return; 932 } 933 934 mutex_lock(&con->sock_mutex); 935 if (con->retries++ > MAX_CONNECT_RETRIES) 936 goto out; 937 938 /* Some odd races can cause double-connects, ignore them */ 939 if (con->sock) { 940 result = 0; 941 goto out; 942 } 943 944 /* Create a socket to communicate with */ 945 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, 946 IPPROTO_TCP, &sock); 947 if (result < 0) 948 goto out_err; 949 950 memset(&saddr, 0, sizeof(saddr)); 951 if (dlm_nodeid_to_addr(con->nodeid, &saddr)) 952 goto out_err; 953 954 sock->sk->sk_user_data = con; 955 con->rx_action = receive_from_sock; 956 con->connect_action = tcp_connect_to_sock; 957 add_sock(sock, con); 958 959 /* Bind to our cluster-known address connecting to avoid 960 routing problems */ 961 memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr)); 962 make_sockaddr(&src_addr, 0, &addr_len); 963 result = sock->ops->bind(sock, (struct sockaddr *) &src_addr, 964 addr_len); 965 if (result < 0) { 966 log_print("could not bind for connect: %d", result); 967 /* This *may* not indicate a critical error */ 968 } 969 970 make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len); 971 972 log_print("connecting to %d", con->nodeid); 973 974 /* Turn off Nagle's algorithm */ 975 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one, 976 sizeof(one)); 977 978 result = 979 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len, 980 O_NONBLOCK); 981 if (result == -EINPROGRESS) 982 result = 0; 983 if (result == 0) 984 goto out; 985 986 out_err: 987 if (con->sock) { 988 sock_release(con->sock); 989 con->sock = NULL; 990 } else if (sock) { 991 sock_release(sock); 992 } 993 /* 994 * Some errors are fatal and this list might need adjusting. For other 995 * errors we try again until the max number of retries is reached. 996 */ 997 if (result != -EHOSTUNREACH && result != -ENETUNREACH && 998 result != -ENETDOWN && result != -EINVAL 999 && result != -EPROTONOSUPPORT) { 1000 lowcomms_connect_sock(con); 1001 result = 0; 1002 } 1003 out: 1004 mutex_unlock(&con->sock_mutex); 1005 return; 1006 } 1007 1008 static struct socket *tcp_create_listen_sock(struct connection *con, 1009 struct sockaddr_storage *saddr) 1010 { 1011 struct socket *sock = NULL; 1012 int result = 0; 1013 int one = 1; 1014 int addr_len; 1015 1016 if (dlm_local_addr[0]->ss_family == AF_INET) 1017 addr_len = sizeof(struct sockaddr_in); 1018 else 1019 addr_len = sizeof(struct sockaddr_in6); 1020 1021 /* Create a socket to communicate with */ 1022 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, 1023 IPPROTO_TCP, &sock); 1024 if (result < 0) { 1025 log_print("Can't create listening comms socket"); 1026 goto create_out; 1027 } 1028 1029 /* Turn off Nagle's algorithm */ 1030 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one, 1031 sizeof(one)); 1032 1033 result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 1034 (char *)&one, sizeof(one)); 1035 1036 if (result < 0) { 1037 log_print("Failed to set SO_REUSEADDR on socket: %d", result); 1038 } 1039 sock->sk->sk_user_data = con; 1040 con->rx_action = tcp_accept_from_sock; 1041 con->connect_action = tcp_connect_to_sock; 1042 con->sock = sock; 1043 1044 /* Bind to our port */ 1045 make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len); 1046 result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len); 1047 if (result < 0) { 1048 log_print("Can't bind to port %d", dlm_config.ci_tcp_port); 1049 sock_release(sock); 1050 sock = NULL; 1051 con->sock = NULL; 1052 goto create_out; 1053 } 1054 result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, 1055 (char *)&one, sizeof(one)); 1056 if (result < 0) { 1057 log_print("Set keepalive failed: %d", result); 1058 } 1059 1060 result = sock->ops->listen(sock, 5); 1061 if (result < 0) { 1062 log_print("Can't listen on port %d", dlm_config.ci_tcp_port); 1063 sock_release(sock); 1064 sock = NULL; 1065 goto create_out; 1066 } 1067 1068 create_out: 1069 return sock; 1070 } 1071 1072 /* Get local addresses */ 1073 static void init_local(void) 1074 { 1075 struct sockaddr_storage sas, *addr; 1076 int i; 1077 1078 dlm_local_count = 0; 1079 for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) { 1080 if (dlm_our_addr(&sas, i)) 1081 break; 1082 1083 addr = kmalloc(sizeof(*addr), GFP_NOFS); 1084 if (!addr) 1085 break; 1086 memcpy(addr, &sas, sizeof(*addr)); 1087 dlm_local_addr[dlm_local_count++] = addr; 1088 } 1089 } 1090 1091 /* Bind to an IP address. SCTP allows multiple address so it can do 1092 multi-homing */ 1093 static int add_sctp_bind_addr(struct connection *sctp_con, 1094 struct sockaddr_storage *addr, 1095 int addr_len, int num) 1096 { 1097 int result = 0; 1098 1099 if (num == 1) 1100 result = kernel_bind(sctp_con->sock, 1101 (struct sockaddr *) addr, 1102 addr_len); 1103 else 1104 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP, 1105 SCTP_SOCKOPT_BINDX_ADD, 1106 (char *)addr, addr_len); 1107 1108 if (result < 0) 1109 log_print("Can't bind to port %d addr number %d", 1110 dlm_config.ci_tcp_port, num); 1111 1112 return result; 1113 } 1114 1115 /* Initialise SCTP socket and bind to all interfaces */ 1116 static int sctp_listen_for_all(void) 1117 { 1118 struct socket *sock = NULL; 1119 struct sockaddr_storage localaddr; 1120 struct sctp_event_subscribe subscribe; 1121 int result = -EINVAL, num = 1, i, addr_len; 1122 struct connection *con = nodeid2con(0, GFP_NOFS); 1123 int bufsize = NEEDED_RMEM; 1124 1125 if (!con) 1126 return -ENOMEM; 1127 1128 log_print("Using SCTP for communications"); 1129 1130 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET, 1131 IPPROTO_SCTP, &sock); 1132 if (result < 0) { 1133 log_print("Can't create comms socket, check SCTP is loaded"); 1134 goto out; 1135 } 1136 1137 /* Listen for events */ 1138 memset(&subscribe, 0, sizeof(subscribe)); 1139 subscribe.sctp_data_io_event = 1; 1140 subscribe.sctp_association_event = 1; 1141 subscribe.sctp_send_failure_event = 1; 1142 subscribe.sctp_shutdown_event = 1; 1143 subscribe.sctp_partial_delivery_event = 1; 1144 1145 result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE, 1146 (char *)&bufsize, sizeof(bufsize)); 1147 if (result) 1148 log_print("Error increasing buffer space on socket %d", result); 1149 1150 result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS, 1151 (char *)&subscribe, sizeof(subscribe)); 1152 if (result < 0) { 1153 log_print("Failed to set SCTP_EVENTS on socket: result=%d", 1154 result); 1155 goto create_delsock; 1156 } 1157 1158 /* Init con struct */ 1159 sock->sk->sk_user_data = con; 1160 con->sock = sock; 1161 con->sock->sk->sk_data_ready = lowcomms_data_ready; 1162 con->rx_action = receive_from_sock; 1163 con->connect_action = sctp_init_assoc; 1164 1165 /* Bind to all interfaces. */ 1166 for (i = 0; i < dlm_local_count; i++) { 1167 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr)); 1168 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len); 1169 1170 result = add_sctp_bind_addr(con, &localaddr, addr_len, num); 1171 if (result) 1172 goto create_delsock; 1173 ++num; 1174 } 1175 1176 result = sock->ops->listen(sock, 5); 1177 if (result < 0) { 1178 log_print("Can't set socket listening"); 1179 goto create_delsock; 1180 } 1181 1182 return 0; 1183 1184 create_delsock: 1185 sock_release(sock); 1186 con->sock = NULL; 1187 out: 1188 return result; 1189 } 1190 1191 static int tcp_listen_for_all(void) 1192 { 1193 struct socket *sock = NULL; 1194 struct connection *con = nodeid2con(0, GFP_NOFS); 1195 int result = -EINVAL; 1196 1197 if (!con) 1198 return -ENOMEM; 1199 1200 /* We don't support multi-homed hosts */ 1201 if (dlm_local_addr[1] != NULL) { 1202 log_print("TCP protocol can't handle multi-homed hosts, " 1203 "try SCTP"); 1204 return -EINVAL; 1205 } 1206 1207 log_print("Using TCP for communications"); 1208 1209 sock = tcp_create_listen_sock(con, dlm_local_addr[0]); 1210 if (sock) { 1211 add_sock(sock, con); 1212 result = 0; 1213 } 1214 else { 1215 result = -EADDRINUSE; 1216 } 1217 1218 return result; 1219 } 1220 1221 1222 1223 static struct writequeue_entry *new_writequeue_entry(struct connection *con, 1224 gfp_t allocation) 1225 { 1226 struct writequeue_entry *entry; 1227 1228 entry = kmalloc(sizeof(struct writequeue_entry), allocation); 1229 if (!entry) 1230 return NULL; 1231 1232 entry->page = alloc_page(allocation); 1233 if (!entry->page) { 1234 kfree(entry); 1235 return NULL; 1236 } 1237 1238 entry->offset = 0; 1239 entry->len = 0; 1240 entry->end = 0; 1241 entry->users = 0; 1242 entry->con = con; 1243 1244 return entry; 1245 } 1246 1247 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc) 1248 { 1249 struct connection *con; 1250 struct writequeue_entry *e; 1251 int offset = 0; 1252 int users = 0; 1253 1254 con = nodeid2con(nodeid, allocation); 1255 if (!con) 1256 return NULL; 1257 1258 spin_lock(&con->writequeue_lock); 1259 e = list_entry(con->writequeue.prev, struct writequeue_entry, list); 1260 if ((&e->list == &con->writequeue) || 1261 (PAGE_CACHE_SIZE - e->end < len)) { 1262 e = NULL; 1263 } else { 1264 offset = e->end; 1265 e->end += len; 1266 users = e->users++; 1267 } 1268 spin_unlock(&con->writequeue_lock); 1269 1270 if (e) { 1271 got_one: 1272 *ppc = page_address(e->page) + offset; 1273 return e; 1274 } 1275 1276 e = new_writequeue_entry(con, allocation); 1277 if (e) { 1278 spin_lock(&con->writequeue_lock); 1279 offset = e->end; 1280 e->end += len; 1281 users = e->users++; 1282 list_add_tail(&e->list, &con->writequeue); 1283 spin_unlock(&con->writequeue_lock); 1284 goto got_one; 1285 } 1286 return NULL; 1287 } 1288 1289 void dlm_lowcomms_commit_buffer(void *mh) 1290 { 1291 struct writequeue_entry *e = (struct writequeue_entry *)mh; 1292 struct connection *con = e->con; 1293 int users; 1294 1295 spin_lock(&con->writequeue_lock); 1296 users = --e->users; 1297 if (users) 1298 goto out; 1299 e->len = e->end - e->offset; 1300 spin_unlock(&con->writequeue_lock); 1301 1302 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) { 1303 queue_work(send_workqueue, &con->swork); 1304 } 1305 return; 1306 1307 out: 1308 spin_unlock(&con->writequeue_lock); 1309 return; 1310 } 1311 1312 /* Send a message */ 1313 static void send_to_sock(struct connection *con) 1314 { 1315 int ret = 0; 1316 const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; 1317 struct writequeue_entry *e; 1318 int len, offset; 1319 int count = 0; 1320 1321 mutex_lock(&con->sock_mutex); 1322 if (con->sock == NULL) 1323 goto out_connect; 1324 1325 spin_lock(&con->writequeue_lock); 1326 for (;;) { 1327 e = list_entry(con->writequeue.next, struct writequeue_entry, 1328 list); 1329 if ((struct list_head *) e == &con->writequeue) 1330 break; 1331 1332 len = e->len; 1333 offset = e->offset; 1334 BUG_ON(len == 0 && e->users == 0); 1335 spin_unlock(&con->writequeue_lock); 1336 1337 ret = 0; 1338 if (len) { 1339 ret = kernel_sendpage(con->sock, e->page, offset, len, 1340 msg_flags); 1341 if (ret == -EAGAIN || ret == 0) { 1342 if (ret == -EAGAIN && 1343 test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) && 1344 !test_and_set_bit(CF_APP_LIMITED, &con->flags)) { 1345 /* Notify TCP that we're limited by the 1346 * application window size. 1347 */ 1348 set_bit(SOCK_NOSPACE, &con->sock->flags); 1349 con->sock->sk->sk_write_pending++; 1350 } 1351 cond_resched(); 1352 goto out; 1353 } 1354 if (ret <= 0) 1355 goto send_error; 1356 } 1357 1358 /* Don't starve people filling buffers */ 1359 if (++count >= MAX_SEND_MSG_COUNT) { 1360 cond_resched(); 1361 count = 0; 1362 } 1363 1364 spin_lock(&con->writequeue_lock); 1365 e->offset += ret; 1366 e->len -= ret; 1367 1368 if (e->len == 0 && e->users == 0) { 1369 list_del(&e->list); 1370 free_entry(e); 1371 continue; 1372 } 1373 } 1374 spin_unlock(&con->writequeue_lock); 1375 out: 1376 mutex_unlock(&con->sock_mutex); 1377 return; 1378 1379 send_error: 1380 mutex_unlock(&con->sock_mutex); 1381 close_connection(con, false); 1382 lowcomms_connect_sock(con); 1383 return; 1384 1385 out_connect: 1386 mutex_unlock(&con->sock_mutex); 1387 if (!test_bit(CF_INIT_PENDING, &con->flags)) 1388 lowcomms_connect_sock(con); 1389 return; 1390 } 1391 1392 static void clean_one_writequeue(struct connection *con) 1393 { 1394 struct writequeue_entry *e, *safe; 1395 1396 spin_lock(&con->writequeue_lock); 1397 list_for_each_entry_safe(e, safe, &con->writequeue, list) { 1398 list_del(&e->list); 1399 free_entry(e); 1400 } 1401 spin_unlock(&con->writequeue_lock); 1402 } 1403 1404 /* Called from recovery when it knows that a node has 1405 left the cluster */ 1406 int dlm_lowcomms_close(int nodeid) 1407 { 1408 struct connection *con; 1409 1410 log_print("closing connection to node %d", nodeid); 1411 con = nodeid2con(nodeid, 0); 1412 if (con) { 1413 clear_bit(CF_CONNECT_PENDING, &con->flags); 1414 clear_bit(CF_WRITE_PENDING, &con->flags); 1415 set_bit(CF_CLOSE, &con->flags); 1416 if (cancel_work_sync(&con->swork)) 1417 log_print("canceled swork for node %d", nodeid); 1418 if (cancel_work_sync(&con->rwork)) 1419 log_print("canceled rwork for node %d", nodeid); 1420 clean_one_writequeue(con); 1421 close_connection(con, true); 1422 } 1423 return 0; 1424 } 1425 1426 /* Receive workqueue function */ 1427 static void process_recv_sockets(struct work_struct *work) 1428 { 1429 struct connection *con = container_of(work, struct connection, rwork); 1430 int err; 1431 1432 clear_bit(CF_READ_PENDING, &con->flags); 1433 do { 1434 err = con->rx_action(con); 1435 } while (!err); 1436 } 1437 1438 /* Send workqueue function */ 1439 static void process_send_sockets(struct work_struct *work) 1440 { 1441 struct connection *con = container_of(work, struct connection, swork); 1442 1443 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) { 1444 con->connect_action(con); 1445 set_bit(CF_WRITE_PENDING, &con->flags); 1446 } 1447 if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags)) 1448 send_to_sock(con); 1449 } 1450 1451 1452 /* Discard all entries on the write queues */ 1453 static void clean_writequeues(void) 1454 { 1455 foreach_conn(clean_one_writequeue); 1456 } 1457 1458 static void work_stop(void) 1459 { 1460 destroy_workqueue(recv_workqueue); 1461 destroy_workqueue(send_workqueue); 1462 } 1463 1464 static int work_start(void) 1465 { 1466 recv_workqueue = alloc_workqueue("dlm_recv", 1467 WQ_UNBOUND | WQ_MEM_RECLAIM, 1); 1468 if (!recv_workqueue) { 1469 log_print("can't start dlm_recv"); 1470 return -ENOMEM; 1471 } 1472 1473 send_workqueue = alloc_workqueue("dlm_send", 1474 WQ_UNBOUND | WQ_MEM_RECLAIM, 1); 1475 if (!send_workqueue) { 1476 log_print("can't start dlm_send"); 1477 destroy_workqueue(recv_workqueue); 1478 return -ENOMEM; 1479 } 1480 1481 return 0; 1482 } 1483 1484 static void stop_conn(struct connection *con) 1485 { 1486 con->flags |= 0x0F; 1487 if (con->sock && con->sock->sk) 1488 con->sock->sk->sk_user_data = NULL; 1489 } 1490 1491 static void free_conn(struct connection *con) 1492 { 1493 close_connection(con, true); 1494 if (con->othercon) 1495 kmem_cache_free(con_cache, con->othercon); 1496 hlist_del(&con->list); 1497 kmem_cache_free(con_cache, con); 1498 } 1499 1500 void dlm_lowcomms_stop(void) 1501 { 1502 /* Set all the flags to prevent any 1503 socket activity. 1504 */ 1505 mutex_lock(&connections_lock); 1506 foreach_conn(stop_conn); 1507 mutex_unlock(&connections_lock); 1508 1509 work_stop(); 1510 1511 mutex_lock(&connections_lock); 1512 clean_writequeues(); 1513 1514 foreach_conn(free_conn); 1515 1516 mutex_unlock(&connections_lock); 1517 kmem_cache_destroy(con_cache); 1518 } 1519 1520 int dlm_lowcomms_start(void) 1521 { 1522 int error = -EINVAL; 1523 struct connection *con; 1524 int i; 1525 1526 for (i = 0; i < CONN_HASH_SIZE; i++) 1527 INIT_HLIST_HEAD(&connection_hash[i]); 1528 1529 init_local(); 1530 if (!dlm_local_count) { 1531 error = -ENOTCONN; 1532 log_print("no local IP address has been set"); 1533 goto out; 1534 } 1535 1536 error = -ENOMEM; 1537 con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection), 1538 __alignof__(struct connection), 0, 1539 NULL); 1540 if (!con_cache) 1541 goto out; 1542 1543 /* Start listening */ 1544 if (dlm_config.ci_protocol == 0) 1545 error = tcp_listen_for_all(); 1546 else 1547 error = sctp_listen_for_all(); 1548 if (error) 1549 goto fail_unlisten; 1550 1551 error = work_start(); 1552 if (error) 1553 goto fail_unlisten; 1554 1555 return 0; 1556 1557 fail_unlisten: 1558 con = nodeid2con(0,0); 1559 if (con) { 1560 close_connection(con, false); 1561 kmem_cache_free(con_cache, con); 1562 } 1563 kmem_cache_destroy(con_cache); 1564 1565 out: 1566 return error; 1567 } 1568