fs/dlm/lowcomms.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /******************************************************************************
   3 *******************************************************************************
   4 **
   5 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   6 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
   7 **
   8 **
   9 *******************************************************************************
  10 ******************************************************************************/
  11
  12 /*
  13  * lowcomms.c
  14  *
  15  * This is the "low-level" comms layer.
  16  *
  17  * It is responsible for sending/receiving messages
  18  * from other nodes in the cluster.
  19  *
  20  * Cluster nodes are referred to by their nodeids. nodeids are
  21  * simply 32 bit numbers to the locking module - if they need to
  22  * be expanded for the cluster infrastructure then that is its
  23  * responsibility. It is this layer's
  24  * responsibility to resolve these into IP address or
  25  * whatever it needs for inter-node communication.
  26  *
  27  * The comms level is two kernel threads that deal mainly with
  28  * the receiving of messages from other nodes and passing them
  29  * up to the mid-level comms layer (which understands the
  30  * message format) for execution by the locking core, and
  31  * a send thread which does all the setting up of connections
  32  * to remote nodes and the sending of data. Threads are not allowed
  33  * to send their own data because it may cause them to wait in times
  34  * of high load. Also, this way, the sending thread can collect together
  35  * messages bound for one node and send them in one block.
  36  *
  37  * lowcomms will choose to use either TCP or SCTP as its transport layer
  38  * depending on the configuration variable 'protocol'. This should be set
  39  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
  40  * cluster-wide mechanism as it must be the same on all nodes of the cluster
  41  * for the DLM to function.
  42  *
  43  */
  44
  45 #include <asm/ioctls.h>
  46 #include <net/sock.h>
  47 #include <net/tcp.h>
  48 #include <linux/pagemap.h>
  49 #include <linux/file.h>
  50 #include <linux/mutex.h>
  51 #include <linux/sctp.h>
  52 #include <linux/slab.h>
  53 #include <net/sctp/sctp.h>
  54 #include <net/ipv6.h>
  55
  56 #include <trace/events/dlm.h>
  57 #include <trace/events/sock.h>
  58
  59 #include "dlm_internal.h"
  60 #include "lowcomms.h"
  61 #include "midcomms.h"
  62 #include "memory.h"
  63 #include "config.h"
  64
  65 #define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(5000)
  66 #define NEEDED_RMEM (4*1024*1024)
  67
  68 struct connection {
  69         struct socket *sock;    /* NULL if not connected */
  70         uint32_t nodeid;        /* So we know who we are in the list */
  71         /* this semaphore is used to allow parallel recv/send in read
  72          * lock mode. When we release a sock we need to held the write lock.
  73          *
  74          * However this is locking code and not nice. When we remove the
  75          * othercon handling we can look into other mechanism to synchronize
  76          * io handling to call sock_release() at the right time.
  77          */
  78         struct rw_semaphore sock_lock;
  79         unsigned long flags;
  80 #define CF_APP_LIMITED 0
  81 #define CF_RECV_PENDING 1
  82 #define CF_SEND_PENDING 2
  83 #define CF_RECV_INTR 3
  84 #define CF_IO_STOP 4
  85 #define CF_IS_OTHERCON 5
  86         struct list_head writequeue;  /* List of outgoing writequeue_entries */
  87         spinlock_t writequeue_lock;
  88         int retries;
  89         struct hlist_node list;
  90         /* due some connect()/accept() races we currently have this cross over
  91          * connection attempt second connection for one node.
  92          *
  93          * There is a solution to avoid the race by introducing a connect
  94          * rule as e.g. our_nodeid > nodeid_to_connect who is allowed to
  95          * connect. Otherside can connect but will only be considered that
  96          * the other side wants to have a reconnect.
  97          *
  98          * However changing to this behaviour will break backwards compatible.
  99          * In a DLM protocol major version upgrade we should remove this!
 100          */
 101         struct connection *othercon;
 102         struct work_struct rwork; /* receive worker */
 103         struct work_struct swork; /* send worker */
 104         wait_queue_head_t shutdown_wait;
 105         unsigned char rx_leftover_buf[DLM_MAX_SOCKET_BUFSIZE];
 106         int rx_leftover;
 107         int mark;
 108         int addr_count;
 109         int curr_addr_index;
 110         struct sockaddr_storage addr[DLM_MAX_ADDR_COUNT];
 111         spinlock_t addrs_lock;
 112         struct rcu_head rcu;
 113 };
 114 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 115
 116 struct listen_connection {
 117         struct socket *sock;
 118         struct work_struct rwork;
 119 };
 120
 121 #define DLM_WQ_REMAIN_BYTES(e) (PAGE_SIZE - e->end)
 122 #define DLM_WQ_LENGTH_BYTES(e) (e->end - e->offset)
 123
 124 /* An entry waiting to be sent */
 125 struct writequeue_entry {
 126         struct list_head list;
 127         struct page *page;
 128         int offset;
 129         int len;
 130         int end;
 131         int users;
 132         bool dirty;
 133         struct connection *con;
 134         struct list_head msgs;
 135         struct kref ref;
 136 };
 137
 138 struct dlm_msg {
 139         struct writequeue_entry *entry;
 140         struct dlm_msg *orig_msg;
 141         bool retransmit;
 142         void *ppc;
 143         int len;
 144         int idx; /* new()/commit() idx exchange */
 145
 146         struct list_head list;
 147         struct kref ref;
 148 };
 149
 150 struct processqueue_entry {
 151         unsigned char *buf;
 152         int nodeid;
 153         int buflen;
 154
 155         struct list_head list;
 156 };
 157
 158 struct dlm_proto_ops {
 159         bool try_new_addr;
 160         const char *name;
 161         int proto;
 162
 163         int (*connect)(struct connection *con, struct socket *sock,
 164                        struct sockaddr *addr, int addr_len);
 165         void (*sockopts)(struct socket *sock);
 166         int (*bind)(struct socket *sock);
 167         int (*listen_validate)(void);
 168         void (*listen_sockopts)(struct socket *sock);
 169         int (*listen_bind)(struct socket *sock);
 170 };
 171
 172 static struct listen_sock_callbacks {
 173         void (*sk_error_report)(struct sock *);
 174         void (*sk_data_ready)(struct sock *);
 175         void (*sk_state_change)(struct sock *);
 176         void (*sk_write_space)(struct sock *);
 177 } listen_sock;
 178
 179 static struct listen_connection listen_con;
 180 static struct sockaddr_storage dlm_local_addr[DLM_MAX_ADDR_COUNT];
 181 static int dlm_local_count;
 182
 183 /* Work queues */
 184 static struct workqueue_struct *io_workqueue;
 185 static struct workqueue_struct *process_workqueue;
 186
 187 static struct hlist_head connection_hash[CONN_HASH_SIZE];
 188 static DEFINE_SPINLOCK(connections_lock);
 189 DEFINE_STATIC_SRCU(connections_srcu);
 190
 191 static const struct dlm_proto_ops *dlm_proto_ops;
 192
 193 #define DLM_IO_SUCCESS 0
 194 #define DLM_IO_END 1
 195 #define DLM_IO_EOF 2
 196 #define DLM_IO_RESCHED 3
 197
 198 static void process_recv_sockets(struct work_struct *work);
 199 static void process_send_sockets(struct work_struct *work);
 200 static void process_dlm_messages(struct work_struct *work);
 201
 202 static DECLARE_WORK(process_work, process_dlm_messages);
 203 static DEFINE_SPINLOCK(processqueue_lock);
 204 static bool process_dlm_messages_pending;
 205 static LIST_HEAD(processqueue);
 206
 207 bool dlm_lowcomms_is_running(void)
 208 {
 209         return !!listen_con.sock;
 210 }
 211
 212 static void lowcomms_queue_swork(struct connection *con)
 213 {
 214         assert_spin_locked(&con->writequeue_lock);
 215
 216         if (!test_bit(CF_IO_STOP, &con->flags) &&
 217             !test_bit(CF_APP_LIMITED, &con->flags) &&
 218             !test_and_set_bit(CF_SEND_PENDING, &con->flags))
 219                 queue_work(io_workqueue, &con->swork);
 220 }
 221
 222 static void lowcomms_queue_rwork(struct connection *con)
 223 {
 224 #ifdef CONFIG_LOCKDEP
 225         WARN_ON_ONCE(!lockdep_sock_is_held(con->sock->sk));
 226 #endif
 227
 228         if (!test_bit(CF_IO_STOP, &con->flags) &&
 229             !test_and_set_bit(CF_RECV_PENDING, &con->flags))
 230                 queue_work(io_workqueue, &con->rwork);
 231 }
 232
 233 static void writequeue_entry_ctor(void *data)
 234 {
 235         struct writequeue_entry *entry = data;
 236
 237         INIT_LIST_HEAD(&entry->msgs);
 238 }
 239
 240 struct kmem_cache *dlm_lowcomms_writequeue_cache_create(void)
 241 {
 242         return kmem_cache_create("dlm_writequeue", sizeof(struct writequeue_entry),
 243                                  0, 0, writequeue_entry_ctor);
 244 }
 245
 246 struct kmem_cache *dlm_lowcomms_msg_cache_create(void)
 247 {
 248         return kmem_cache_create("dlm_msg", sizeof(struct dlm_msg), 0, 0, NULL);
 249 }
 250
 251 /* need to held writequeue_lock */
 252 static struct writequeue_entry *con_next_wq(struct connection *con)
 253 {
 254         struct writequeue_entry *e;
 255
 256         e = list_first_entry_or_null(&con->writequeue, struct writequeue_entry,
 257                                      list);
 258         /* if len is zero nothing is to send, if there are users filling
 259          * buffers we wait until the users are done so we can send more.
 260          */
 261         if (!e || e->users || e->len == 0)
 262                 return NULL;
 263
 264         return e;
 265 }
 266
 267 static struct connection *__find_con(int nodeid, int r)
 268 {
 269         struct connection *con;
 270
 271         hlist_for_each_entry_rcu(con, &connection_hash[r], list) {
 272                 if (con->nodeid == nodeid)
 273                         return con;
 274         }
 275
 276         return NULL;
 277 }
 278
 279 static void dlm_con_init(struct connection *con, int nodeid)
 280 {
 281         con->nodeid = nodeid;
 282         init_rwsem(&con->sock_lock);
 283         INIT_LIST_HEAD(&con->writequeue);
 284         spin_lock_init(&con->writequeue_lock);
 285         INIT_WORK(&con->swork, process_send_sockets);
 286         INIT_WORK(&con->rwork, process_recv_sockets);
 287         spin_lock_init(&con->addrs_lock);
 288         init_waitqueue_head(&con->shutdown_wait);
 289 }
 290
 291 /*
 292  * If 'allocation' is zero then we don't attempt to create a new
 293  * connection structure for this node.
 294  */
 295 static struct connection *nodeid2con(int nodeid, gfp_t alloc)
 296 {
 297         struct connection *con, *tmp;
 298         int r;
 299
 300         r = nodeid_hash(nodeid);
 301         con = __find_con(nodeid, r);
 302         if (con || !alloc)
 303                 return con;
 304
 305         con = kzalloc(sizeof(*con), alloc);
 306         if (!con)
 307                 return NULL;
 308
 309         dlm_con_init(con, nodeid);
 310
 311         spin_lock(&connections_lock);
 312         /* Because multiple workqueues/threads calls this function it can
 313          * race on multiple cpu's. Instead of locking hot path __find_con()
 314          * we just check in rare cases of recently added nodes again
 315          * under protection of connections_lock. If this is the case we
 316          * abort our connection creation and return the existing connection.
 317          */
 318         tmp = __find_con(nodeid, r);
 319         if (tmp) {
 320                 spin_unlock(&connections_lock);
 321                 kfree(con);
 322                 return tmp;
 323         }
 324
 325         hlist_add_head_rcu(&con->list, &connection_hash[r]);
 326         spin_unlock(&connections_lock);
 327
 328         return con;
 329 }
 330
 331 static int addr_compare(const struct sockaddr_storage *x,
 332                         const struct sockaddr_storage *y)
 333 {
 334         switch (x->ss_family) {
 335         case AF_INET: {
 336                 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
 337                 struct sockaddr_in *siny = (struct sockaddr_in *)y;
 338                 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
 339                         return 0;
 340                 if (sinx->sin_port != siny->sin_port)
 341                         return 0;
 342                 break;
 343         }
 344         case AF_INET6: {
 345                 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
 346                 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
 347                 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
 348                         return 0;
 349                 if (sinx->sin6_port != siny->sin6_port)
 350                         return 0;
 351                 break;
 352         }
 353         default:
 354                 return 0;
 355         }
 356         return 1;
 357 }
 358
 359 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 360                           struct sockaddr *sa_out, bool try_new_addr,
 361                           unsigned int *mark)
 362 {
 363         struct sockaddr_storage sas;
 364         struct connection *con;
 365         int idx;
 366
 367         if (!dlm_local_count)
 368                 return -1;
 369
 370         idx = srcu_read_lock(&connections_srcu);
 371         con = nodeid2con(nodeid, 0);
 372         if (!con) {
 373                 srcu_read_unlock(&connections_srcu, idx);
 374                 return -ENOENT;
 375         }
 376
 377         spin_lock(&con->addrs_lock);
 378         if (!con->addr_count) {
 379                 spin_unlock(&con->addrs_lock);
 380                 srcu_read_unlock(&connections_srcu, idx);
 381                 return -ENOENT;
 382         }
 383
 384         memcpy(&sas, &con->addr[con->curr_addr_index],
 385                sizeof(struct sockaddr_storage));
 386
 387         if (try_new_addr) {
 388                 con->curr_addr_index++;
 389                 if (con->curr_addr_index == con->addr_count)
 390                         con->curr_addr_index = 0;
 391         }
 392
 393         *mark = con->mark;
 394         spin_unlock(&con->addrs_lock);
 395
 396         if (sas_out)
 397                 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
 398
 399         if (!sa_out) {
 400                 srcu_read_unlock(&connections_srcu, idx);
 401                 return 0;
 402         }
 403
 404         if (dlm_local_addr[0].ss_family == AF_INET) {
 405                 struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
 406                 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
 407                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
 408         } else {
 409                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
 410                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
 411                 ret6->sin6_addr = in6->sin6_addr;
 412         }
 413
 414         srcu_read_unlock(&connections_srcu, idx);
 415         return 0;
 416 }
 417
 418 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid,
 419                           unsigned int *mark)
 420 {
 421         struct connection *con;
 422         int i, idx, addr_i;
 423
 424         idx = srcu_read_lock(&connections_srcu);
 425         for (i = 0; i < CONN_HASH_SIZE; i++) {
 426                 hlist_for_each_entry_rcu(con, &connection_hash[i], list) {
 427                         WARN_ON_ONCE(!con->addr_count);
 428
 429                         spin_lock(&con->addrs_lock);
 430                         for (addr_i = 0; addr_i < con->addr_count; addr_i++) {
 431                                 if (addr_compare(&con->addr[addr_i], addr)) {
 432                                         *nodeid = con->nodeid;
 433                                         *mark = con->mark;
 434                                         spin_unlock(&con->addrs_lock);
 435                                         srcu_read_unlock(&connections_srcu, idx);
 436                                         return 0;
 437                                 }
 438                         }
 439                         spin_unlock(&con->addrs_lock);
 440                 }
 441         }
 442         srcu_read_unlock(&connections_srcu, idx);
 443
 444         return -ENOENT;
 445 }
 446
 447 static bool dlm_lowcomms_con_has_addr(const struct connection *con,
 448                                       const struct sockaddr_storage *addr)
 449 {
 450         int i;
 451
 452         for (i = 0; i < con->addr_count; i++) {
 453                 if (addr_compare(&con->addr[i], addr))
 454                         return true;
 455         }
 456
 457         return false;
 458 }
 459
 460 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 461 {
 462         struct connection *con;
 463         bool ret, idx;
 464
 465         idx = srcu_read_lock(&connections_srcu);
 466         con = nodeid2con(nodeid, GFP_NOFS);
 467         if (!con) {
 468                 srcu_read_unlock(&connections_srcu, idx);
 469                 return -ENOMEM;
 470         }
 471
 472         spin_lock(&con->addrs_lock);
 473         if (!con->addr_count) {
 474                 memcpy(&con->addr[0], addr, sizeof(*addr));
 475                 con->addr_count = 1;
 476                 con->mark = dlm_config.ci_mark;
 477                 spin_unlock(&con->addrs_lock);
 478                 srcu_read_unlock(&connections_srcu, idx);
 479                 return 0;
 480         }
 481
 482         ret = dlm_lowcomms_con_has_addr(con, addr);
 483         if (ret) {
 484                 spin_unlock(&con->addrs_lock);
 485                 srcu_read_unlock(&connections_srcu, idx);
 486                 return -EEXIST;
 487         }
 488
 489         if (con->addr_count >= DLM_MAX_ADDR_COUNT) {
 490                 spin_unlock(&con->addrs_lock);
 491                 srcu_read_unlock(&connections_srcu, idx);
 492                 return -ENOSPC;
 493         }
 494
 495         memcpy(&con->addr[con->addr_count++], addr, sizeof(*addr));
 496         srcu_read_unlock(&connections_srcu, idx);
 497         spin_unlock(&con->addrs_lock);
 498         return 0;
 499 }
 500
 501 /* Data available on socket or listen socket received a connect */
 502 static void lowcomms_data_ready(struct sock *sk)
 503 {
 504         struct connection *con = sock2con(sk);
 505
 506         trace_sk_data_ready(sk);
 507
 508         set_bit(CF_RECV_INTR, &con->flags);
 509         lowcomms_queue_rwork(con);
 510 }
 511
 512 static void lowcomms_write_space(struct sock *sk)
 513 {
 514         struct connection *con = sock2con(sk);
 515
 516         clear_bit(SOCK_NOSPACE, &con->sock->flags);
 517
 518         spin_lock_bh(&con->writequeue_lock);
 519         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 520                 con->sock->sk->sk_write_pending--;
 521                 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
 522         }
 523
 524         lowcomms_queue_swork(con);
 525         spin_unlock_bh(&con->writequeue_lock);
 526 }
 527
 528 static void lowcomms_state_change(struct sock *sk)
 529 {
 530         /* SCTP layer is not calling sk_data_ready when the connection
 531          * is done, so we catch the signal through here.
 532          */
 533         if (sk->sk_shutdown == RCV_SHUTDOWN)
 534                 lowcomms_data_ready(sk);
 535 }
 536
 537 static void lowcomms_listen_data_ready(struct sock *sk)
 538 {
 539         trace_sk_data_ready(sk);
 540
 541         queue_work(io_workqueue, &listen_con.rwork);
 542 }
 543
 544 int dlm_lowcomms_connect_node(int nodeid)
 545 {
 546         struct connection *con;
 547         int idx;
 548
 549         if (nodeid == dlm_our_nodeid())
 550                 return 0;
 551
 552         idx = srcu_read_lock(&connections_srcu);
 553         con = nodeid2con(nodeid, 0);
 554         if (WARN_ON_ONCE(!con)) {
 555                 srcu_read_unlock(&connections_srcu, idx);
 556                 return -ENOENT;
 557         }
 558
 559         down_read(&con->sock_lock);
 560         if (!con->sock) {
 561                 spin_lock_bh(&con->writequeue_lock);
 562                 lowcomms_queue_swork(con);
 563                 spin_unlock_bh(&con->writequeue_lock);
 564         }
 565         up_read(&con->sock_lock);
 566         srcu_read_unlock(&connections_srcu, idx);
 567
 568         cond_resched();
 569         return 0;
 570 }
 571
 572 int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark)
 573 {
 574         struct connection *con;
 575         int idx;
 576
 577         idx = srcu_read_lock(&connections_srcu);
 578         con = nodeid2con(nodeid, 0);
 579         if (!con) {
 580                 srcu_read_unlock(&connections_srcu, idx);
 581                 return -ENOENT;
 582         }
 583
 584         spin_lock(&con->addrs_lock);
 585         con->mark = mark;
 586         spin_unlock(&con->addrs_lock);
 587         srcu_read_unlock(&connections_srcu, idx);
 588         return 0;
 589 }
 590
 591 static void lowcomms_error_report(struct sock *sk)
 592 {
 593         struct connection *con = sock2con(sk);
 594         struct inet_sock *inet;
 595
 596         inet = inet_sk(sk);
 597         switch (sk->sk_family) {
 598         case AF_INET:
 599                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 600                                    "sending to node %d at %pI4, dport %d, "
 601                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 602                                    con->nodeid, &inet->inet_daddr,
 603                                    ntohs(inet->inet_dport), sk->sk_err,
 604                                    READ_ONCE(sk->sk_err_soft));
 605                 break;
 606 #if IS_ENABLED(CONFIG_IPV6)
 607         case AF_INET6:
 608                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 609                                    "sending to node %d at %pI6c, "
 610                                    "dport %d, sk_err=%d/%d\n", dlm_our_nodeid(),
 611                                    con->nodeid, &sk->sk_v6_daddr,
 612                                    ntohs(inet->inet_dport), sk->sk_err,
 613                                    READ_ONCE(sk->sk_err_soft));
 614                 break;
 615 #endif
 616         default:
 617                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 618                                    "invalid socket family %d set, "
 619                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 620                                    sk->sk_family, sk->sk_err,
 621                                    READ_ONCE(sk->sk_err_soft));
 622                 break;
 623         }
 624
 625         dlm_midcomms_unack_msg_resend(con->nodeid);
 626
 627         listen_sock.sk_error_report(sk);
 628 }
 629
 630 static void restore_callbacks(struct sock *sk)
 631 {
 632 #ifdef CONFIG_LOCKDEP
 633         WARN_ON_ONCE(!lockdep_sock_is_held(sk));
 634 #endif
 635
 636         sk->sk_user_data = NULL;
 637         sk->sk_data_ready = listen_sock.sk_data_ready;
 638         sk->sk_state_change = listen_sock.sk_state_change;
 639         sk->sk_write_space = listen_sock.sk_write_space;
 640         sk->sk_error_report = listen_sock.sk_error_report;
 641 }
 642
 643 /* Make a socket active */
 644 static void add_sock(struct socket *sock, struct connection *con)
 645 {
 646         struct sock *sk = sock->sk;
 647
 648         lock_sock(sk);
 649         con->sock = sock;
 650
 651         sk->sk_user_data = con;
 652         sk->sk_data_ready = lowcomms_data_ready;
 653         sk->sk_write_space = lowcomms_write_space;
 654         if (dlm_config.ci_protocol == DLM_PROTO_SCTP)
 655                 sk->sk_state_change = lowcomms_state_change;
 656         sk->sk_allocation = GFP_NOFS;
 657         sk->sk_use_task_frag = false;
 658         sk->sk_error_report = lowcomms_error_report;
 659         release_sock(sk);
 660 }
 661
 662 /* Add the port number to an IPv6 or 4 sockaddr and return the address
 663    length */
 664 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 665                           int *addr_len)
 666 {
 667         saddr->ss_family =  dlm_local_addr[0].ss_family;
 668         if (saddr->ss_family == AF_INET) {
 669                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 670                 in4_addr->sin_port = cpu_to_be16(port);
 671                 *addr_len = sizeof(struct sockaddr_in);
 672                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
 673         } else {
 674                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
 675                 in6_addr->sin6_port = cpu_to_be16(port);
 676                 *addr_len = sizeof(struct sockaddr_in6);
 677         }
 678         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
 679 }
 680
 681 static void dlm_page_release(struct kref *kref)
 682 {
 683         struct writequeue_entry *e = container_of(kref, struct writequeue_entry,
 684                                                   ref);
 685
 686         __free_page(e->page);
 687         dlm_free_writequeue(e);
 688 }
 689
 690 static void dlm_msg_release(struct kref *kref)
 691 {
 692         struct dlm_msg *msg = container_of(kref, struct dlm_msg, ref);
 693
 694         kref_put(&msg->entry->ref, dlm_page_release);
 695         dlm_free_msg(msg);
 696 }
 697
 698 static void free_entry(struct writequeue_entry *e)
 699 {
 700         struct dlm_msg *msg, *tmp;
 701
 702         list_for_each_entry_safe(msg, tmp, &e->msgs, list) {
 703                 if (msg->orig_msg) {
 704                         msg->orig_msg->retransmit = false;
 705                         kref_put(&msg->orig_msg->ref, dlm_msg_release);
 706                 }
 707
 708                 list_del(&msg->list);
 709                 kref_put(&msg->ref, dlm_msg_release);
 710         }
 711
 712         list_del(&e->list);
 713         kref_put(&e->ref, dlm_page_release);
 714 }
 715
 716 static void dlm_close_sock(struct socket **sock)
 717 {
 718         lock_sock((*sock)->sk);
 719         restore_callbacks((*sock)->sk);
 720         release_sock((*sock)->sk);
 721
 722         sock_release(*sock);
 723         *sock = NULL;
 724 }
 725
 726 static void allow_connection_io(struct connection *con)
 727 {
 728         if (con->othercon)
 729                 clear_bit(CF_IO_STOP, &con->othercon->flags);
 730         clear_bit(CF_IO_STOP, &con->flags);
 731 }
 732
 733 static void stop_connection_io(struct connection *con)
 734 {
 735         if (con->othercon)
 736                 stop_connection_io(con->othercon);
 737
 738         down_write(&con->sock_lock);
 739         if (con->sock) {
 740                 lock_sock(con->sock->sk);
 741                 restore_callbacks(con->sock->sk);
 742
 743                 spin_lock_bh(&con->writequeue_lock);
 744                 set_bit(CF_IO_STOP, &con->flags);
 745                 spin_unlock_bh(&con->writequeue_lock);
 746                 release_sock(con->sock->sk);
 747         } else {
 748                 spin_lock_bh(&con->writequeue_lock);
 749                 set_bit(CF_IO_STOP, &con->flags);
 750                 spin_unlock_bh(&con->writequeue_lock);
 751         }
 752         up_write(&con->sock_lock);
 753
 754         cancel_work_sync(&con->swork);
 755         cancel_work_sync(&con->rwork);
 756 }
 757
 758 /* Close a remote connection and tidy up */
 759 static void close_connection(struct connection *con, bool and_other)
 760 {
 761         struct writequeue_entry *e;
 762
 763         if (con->othercon && and_other)
 764                 close_connection(con->othercon, false);
 765
 766         down_write(&con->sock_lock);
 767         if (!con->sock) {
 768                 up_write(&con->sock_lock);
 769                 return;
 770         }
 771
 772         dlm_close_sock(&con->sock);
 773
 774         /* if we send a writequeue entry only a half way, we drop the
 775          * whole entry because reconnection and that we not start of the
 776          * middle of a msg which will confuse the other end.
 777          *
 778          * we can always drop messages because retransmits, but what we
 779          * cannot allow is to transmit half messages which may be processed
 780          * at the other side.
 781          *
 782          * our policy is to start on a clean state when disconnects, we don't
 783          * know what's send/received on transport layer in this case.
 784          */
 785         spin_lock_bh(&con->writequeue_lock);
 786         if (!list_empty(&con->writequeue)) {
 787                 e = list_first_entry(&con->writequeue, struct writequeue_entry,
 788                                      list);
 789                 if (e->dirty)
 790                         free_entry(e);
 791         }
 792         spin_unlock_bh(&con->writequeue_lock);
 793
 794         con->rx_leftover = 0;
 795         con->retries = 0;
 796         clear_bit(CF_APP_LIMITED, &con->flags);
 797         clear_bit(CF_RECV_PENDING, &con->flags);
 798         clear_bit(CF_SEND_PENDING, &con->flags);
 799         up_write(&con->sock_lock);
 800 }
 801
 802 static void shutdown_connection(struct connection *con, bool and_other)
 803 {
 804         int ret;
 805
 806         if (con->othercon && and_other)
 807                 shutdown_connection(con->othercon, false);
 808
 809         flush_workqueue(io_workqueue);
 810         down_read(&con->sock_lock);
 811         /* nothing to shutdown */
 812         if (!con->sock) {
 813                 up_read(&con->sock_lock);
 814                 return;
 815         }
 816
 817         ret = kernel_sock_shutdown(con->sock, SHUT_WR);
 818         up_read(&con->sock_lock);
 819         if (ret) {
 820                 log_print("Connection %p failed to shutdown: %d will force close",
 821                           con, ret);
 822                 goto force_close;
 823         } else {
 824                 ret = wait_event_timeout(con->shutdown_wait, !con->sock,
 825                                          DLM_SHUTDOWN_WAIT_TIMEOUT);
 826                 if (ret == 0) {
 827                         log_print("Connection %p shutdown timed out, will force close",
 828                                   con);
 829                         goto force_close;
 830                 }
 831         }
 832
 833         return;
 834
 835 force_close:
 836         close_connection(con, false);
 837 }
 838
 839 static struct processqueue_entry *new_processqueue_entry(int nodeid,
 840                                                          int buflen)
 841 {
 842         struct processqueue_entry *pentry;
 843
 844         pentry = kmalloc(sizeof(*pentry), GFP_NOFS);
 845         if (!pentry)
 846                 return NULL;
 847
 848         pentry->buf = kmalloc(buflen, GFP_NOFS);
 849         if (!pentry->buf) {
 850                 kfree(pentry);
 851                 return NULL;
 852         }
 853
 854         pentry->nodeid = nodeid;
 855         return pentry;
 856 }
 857
 858 static void free_processqueue_entry(struct processqueue_entry *pentry)
 859 {
 860         kfree(pentry->buf);
 861         kfree(pentry);
 862 }
 863
 864 struct dlm_processed_nodes {
 865         int nodeid;
 866
 867         struct list_head list;
 868 };
 869
 870 static void add_processed_node(int nodeid, struct list_head *processed_nodes)
 871 {
 872         struct dlm_processed_nodes *n;
 873
 874         list_for_each_entry(n, processed_nodes, list) {
 875                 /* we already remembered this node */
 876                 if (n->nodeid == nodeid)
 877                         return;
 878         }
 879
 880         /* if it's fails in worst case we simple don't send an ack back.
 881          * We try it next time.
 882          */
 883         n = kmalloc(sizeof(*n), GFP_NOFS);
 884         if (!n)
 885                 return;
 886
 887         n->nodeid = nodeid;
 888         list_add(&n->list, processed_nodes);
 889 }
 890
 891 static void process_dlm_messages(struct work_struct *work)
 892 {
 893         struct dlm_processed_nodes *n, *n_tmp;
 894         struct processqueue_entry *pentry;
 895         LIST_HEAD(processed_nodes);
 896
 897         spin_lock(&processqueue_lock);
 898         pentry = list_first_entry_or_null(&processqueue,
 899                                           struct processqueue_entry, list);
 900         if (WARN_ON_ONCE(!pentry)) {
 901                 spin_unlock(&processqueue_lock);
 902                 return;
 903         }
 904
 905         list_del(&pentry->list);
 906         spin_unlock(&processqueue_lock);
 907
 908         for (;;) {
 909                 dlm_process_incoming_buffer(pentry->nodeid, pentry->buf,
 910                                             pentry->buflen);
 911                 add_processed_node(pentry->nodeid, &processed_nodes);
 912                 free_processqueue_entry(pentry);
 913
 914                 spin_lock(&processqueue_lock);
 915                 pentry = list_first_entry_or_null(&processqueue,
 916                                                   struct processqueue_entry, list);
 917                 if (!pentry) {
 918                         process_dlm_messages_pending = false;
 919                         spin_unlock(&processqueue_lock);
 920                         break;
 921                 }
 922
 923                 list_del(&pentry->list);
 924                 spin_unlock(&processqueue_lock);
 925         }
 926
 927         /* send ack back after we processed couple of messages */
 928         list_for_each_entry_safe(n, n_tmp, &processed_nodes, list) {
 929                 list_del(&n->list);
 930                 dlm_midcomms_receive_done(n->nodeid);
 931                 kfree(n);
 932         }
 933 }
 934
 935 /* Data received from remote end */
 936 static int receive_from_sock(struct connection *con, int buflen)
 937 {
 938         struct processqueue_entry *pentry;
 939         int ret, buflen_real;
 940         struct msghdr msg;
 941         struct kvec iov;
 942
 943         pentry = new_processqueue_entry(con->nodeid, buflen);
 944         if (!pentry)
 945                 return DLM_IO_RESCHED;
 946
 947         memcpy(pentry->buf, con->rx_leftover_buf, con->rx_leftover);
 948
 949         /* calculate new buffer parameter regarding last receive and
 950          * possible leftover bytes
 951          */
 952         iov.iov_base = pentry->buf + con->rx_leftover;
 953         iov.iov_len = buflen - con->rx_leftover;
 954
 955         memset(&msg, 0, sizeof(msg));
 956         msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
 957         clear_bit(CF_RECV_INTR, &con->flags);
 958 again:
 959         ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
 960                              msg.msg_flags);
 961         trace_dlm_recv(con->nodeid, ret);
 962         if (ret == -EAGAIN) {
 963                 lock_sock(con->sock->sk);
 964                 if (test_and_clear_bit(CF_RECV_INTR, &con->flags)) {
 965                         release_sock(con->sock->sk);
 966                         goto again;
 967                 }
 968
 969                 clear_bit(CF_RECV_PENDING, &con->flags);
 970                 release_sock(con->sock->sk);
 971                 free_processqueue_entry(pentry);
 972                 return DLM_IO_END;
 973         } else if (ret == 0) {
 974                 /* close will clear CF_RECV_PENDING */
 975                 free_processqueue_entry(pentry);
 976                 return DLM_IO_EOF;
 977         } else if (ret < 0) {
 978                 free_processqueue_entry(pentry);
 979                 return ret;
 980         }
 981
 982         /* new buflen according readed bytes and leftover from last receive */
 983         buflen_real = ret + con->rx_leftover;
 984         ret = dlm_validate_incoming_buffer(con->nodeid, pentry->buf,
 985                                            buflen_real);
 986         if (ret < 0) {
 987                 free_processqueue_entry(pentry);
 988                 return ret;
 989         }
 990
 991         pentry->buflen = ret;
 992
 993         /* calculate leftover bytes from process and put it into begin of
 994          * the receive buffer, so next receive we have the full message
 995          * at the start address of the receive buffer.
 996          */
 997         con->rx_leftover = buflen_real - ret;
 998         memmove(con->rx_leftover_buf, pentry->buf + ret,
 999                 con->rx_leftover);
1000
1001         spin_lock(&processqueue_lock);
1002         list_add_tail(&pentry->list, &processqueue);
1003         if (!process_dlm_messages_pending) {
1004                 process_dlm_messages_pending = true;
1005                 queue_work(process_workqueue, &process_work);
1006         }
1007         spin_unlock(&processqueue_lock);
1008
1009         return DLM_IO_SUCCESS;
1010 }
1011
1012 /* Listening socket is busy, accept a connection */
1013 static int accept_from_sock(void)
1014 {
1015         struct sockaddr_storage peeraddr;
1016         int len, idx, result, nodeid;
1017         struct connection *newcon;
1018         struct socket *newsock;
1019         unsigned int mark;
1020
1021         result = kernel_accept(listen_con.sock, &newsock, O_NONBLOCK);
1022         if (result == -EAGAIN)
1023                 return DLM_IO_END;
1024         else if (result < 0)
1025                 goto accept_err;
1026
1027         /* Get the connected socket's peer */
1028         memset(&peeraddr, 0, sizeof(peeraddr));
1029         len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
1030         if (len < 0) {
1031                 result = -ECONNABORTED;
1032                 goto accept_err;
1033         }
1034
1035         /* Get the new node's NODEID */
1036         make_sockaddr(&peeraddr, 0, &len);
1037         if (addr_to_nodeid(&peeraddr, &nodeid, &mark)) {
1038                 switch (peeraddr.ss_family) {
1039                 case AF_INET: {
1040                         struct sockaddr_in *sin = (struct sockaddr_in *)&peeraddr;
1041
1042                         log_print("connect from non cluster IPv4 node %pI4",
1043                                   &sin->sin_addr);
1044                         break;
1045                 }
1046 #if IS_ENABLED(CONFIG_IPV6)
1047                 case AF_INET6: {
1048                         struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&peeraddr;
1049
1050                         log_print("connect from non cluster IPv6 node %pI6c",
1051                                   &sin6->sin6_addr);
1052                         break;
1053                 }
1054 #endif
1055                 default:
1056                         log_print("invalid family from non cluster node");
1057                         break;
1058                 }
1059
1060                 sock_release(newsock);
1061                 return -1;
1062         }
1063
1064         log_print("got connection from %d", nodeid);
1065
1066         /*  Check to see if we already have a connection to this node. This
1067          *  could happen if the two nodes initiate a connection at roughly
1068          *  the same time and the connections cross on the wire.
1069          *  In this case we store the incoming one in "othercon"
1070          */
1071         idx = srcu_read_lock(&connections_srcu);
1072         newcon = nodeid2con(nodeid, 0);
1073         if (WARN_ON_ONCE(!newcon)) {
1074                 srcu_read_unlock(&connections_srcu, idx);
1075                 result = -ENOENT;
1076                 goto accept_err;
1077         }
1078
1079         sock_set_mark(newsock->sk, mark);
1080
1081         down_write(&newcon->sock_lock);
1082         if (newcon->sock) {
1083                 struct connection *othercon = newcon->othercon;
1084
1085                 if (!othercon) {
1086                         othercon = kzalloc(sizeof(*othercon), GFP_NOFS);
1087                         if (!othercon) {
1088                                 log_print("failed to allocate incoming socket");
1089                                 up_write(&newcon->sock_lock);
1090                                 srcu_read_unlock(&connections_srcu, idx);
1091                                 result = -ENOMEM;
1092                                 goto accept_err;
1093                         }
1094
1095                         dlm_con_init(othercon, nodeid);
1096                         lockdep_set_subclass(&othercon->sock_lock, 1);
1097                         newcon->othercon = othercon;
1098                         set_bit(CF_IS_OTHERCON, &othercon->flags);
1099                 } else {
1100                         /* close other sock con if we have something new */
1101                         close_connection(othercon, false);
1102                 }
1103
1104                 down_write(&othercon->sock_lock);
1105                 add_sock(newsock, othercon);
1106
1107                 /* check if we receved something while adding */
1108                 lock_sock(othercon->sock->sk);
1109                 lowcomms_queue_rwork(othercon);
1110                 release_sock(othercon->sock->sk);
1111                 up_write(&othercon->sock_lock);
1112         }
1113         else {
1114                 /* accept copies the sk after we've saved the callbacks, so we
1115                    don't want to save them a second time or comm errors will
1116                    result in calling sk_error_report recursively. */
1117                 add_sock(newsock, newcon);
1118
1119                 /* check if we receved something while adding */
1120                 lock_sock(newcon->sock->sk);
1121                 lowcomms_queue_rwork(newcon);
1122                 release_sock(newcon->sock->sk);
1123         }
1124         up_write(&newcon->sock_lock);
1125         srcu_read_unlock(&connections_srcu, idx);
1126
1127         return DLM_IO_SUCCESS;
1128
1129 accept_err:
1130         if (newsock)
1131                 sock_release(newsock);
1132
1133         return result;
1134 }
1135
1136 /*
1137  * writequeue_entry_complete - try to delete and free write queue entry
1138  * @e: write queue entry to try to delete
1139  * @completed: bytes completed
1140  *
1141  * writequeue_lock must be held.
1142  */
1143 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
1144 {
1145         e->offset += completed;
1146         e->len -= completed;
1147         /* signal that page was half way transmitted */
1148         e->dirty = true;
1149
1150         if (e->len == 0 && e->users == 0)
1151                 free_entry(e);
1152 }
1153
1154 /*
1155  * sctp_bind_addrs - bind a SCTP socket to all our addresses
1156  */
1157 static int sctp_bind_addrs(struct socket *sock, uint16_t port)
1158 {
1159         struct sockaddr_storage localaddr;
1160         struct sockaddr *addr = (struct sockaddr *)&localaddr;
1161         int i, addr_len, result = 0;
1162
1163         for (i = 0; i < dlm_local_count; i++) {
1164                 memcpy(&localaddr, &dlm_local_addr[i], sizeof(localaddr));
1165                 make_sockaddr(&localaddr, port, &addr_len);
1166
1167                 if (!i)
1168                         result = kernel_bind(sock, addr, addr_len);
1169                 else
1170                         result = sock_bind_add(sock->sk, addr, addr_len);
1171
1172                 if (result < 0) {
1173                         log_print("Can't bind to %d addr number %d, %d.\n",
1174                                   port, i + 1, result);
1175                         break;
1176                 }
1177         }
1178         return result;
1179 }
1180
1181 /* Get local addresses */
1182 static void init_local(void)
1183 {
1184         struct sockaddr_storage sas;
1185         int i;
1186
1187         dlm_local_count = 0;
1188         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1189                 if (dlm_our_addr(&sas, i))
1190                         break;
1191
1192                 memcpy(&dlm_local_addr[dlm_local_count++], &sas, sizeof(sas));
1193         }
1194 }
1195
1196 static struct writequeue_entry *new_writequeue_entry(struct connection *con)
1197 {
1198         struct writequeue_entry *entry;
1199
1200         entry = dlm_allocate_writequeue();
1201         if (!entry)
1202                 return NULL;
1203
1204         entry->page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
1205         if (!entry->page) {
1206                 dlm_free_writequeue(entry);
1207                 return NULL;
1208         }
1209
1210         entry->offset = 0;
1211         entry->len = 0;
1212         entry->end = 0;
1213         entry->dirty = false;
1214         entry->con = con;
1215         entry->users = 1;
1216         kref_init(&entry->ref);
1217         return entry;
1218 }
1219
1220 static struct writequeue_entry *new_wq_entry(struct connection *con, int len,
1221                                              char **ppc, void (*cb)(void *data),
1222                                              void *data)
1223 {
1224         struct writequeue_entry *e;
1225
1226         spin_lock_bh(&con->writequeue_lock);
1227         if (!list_empty(&con->writequeue)) {
1228                 e = list_last_entry(&con->writequeue, struct writequeue_entry, list);
1229                 if (DLM_WQ_REMAIN_BYTES(e) >= len) {
1230                         kref_get(&e->ref);
1231
1232                         *ppc = page_address(e->page) + e->end;
1233                         if (cb)
1234                                 cb(data);
1235
1236                         e->end += len;
1237                         e->users++;
1238                         goto out;
1239                 }
1240         }
1241
1242         e = new_writequeue_entry(con);
1243         if (!e)
1244                 goto out;
1245
1246         kref_get(&e->ref);
1247         *ppc = page_address(e->page);
1248         e->end += len;
1249         if (cb)
1250                 cb(data);
1251
1252         list_add_tail(&e->list, &con->writequeue);
1253
1254 out:
1255         spin_unlock_bh(&con->writequeue_lock);
1256         return e;
1257 };
1258
1259 static struct dlm_msg *dlm_lowcomms_new_msg_con(struct connection *con, int len,
1260                                                 gfp_t allocation, char **ppc,
1261                                                 void (*cb)(void *data),
1262                                                 void *data)
1263 {
1264         struct writequeue_entry *e;
1265         struct dlm_msg *msg;
1266
1267         msg = dlm_allocate_msg(allocation);
1268         if (!msg)
1269                 return NULL;
1270
1271         kref_init(&msg->ref);
1272
1273         e = new_wq_entry(con, len, ppc, cb, data);
1274         if (!e) {
1275                 dlm_free_msg(msg);
1276                 return NULL;
1277         }
1278
1279         msg->retransmit = false;
1280         msg->orig_msg = NULL;
1281         msg->ppc = *ppc;
1282         msg->len = len;
1283         msg->entry = e;
1284
1285         return msg;
1286 }
1287
1288 /* avoid false positive for nodes_srcu, unlock happens in
1289  * dlm_lowcomms_commit_msg which is a must call if success
1290  */
1291 #ifndef __CHECKER__
1292 struct dlm_msg *dlm_lowcomms_new_msg(int nodeid, int len, gfp_t allocation,
1293                                      char **ppc, void (*cb)(void *data),
1294                                      void *data)
1295 {
1296         struct connection *con;
1297         struct dlm_msg *msg;
1298         int idx;
1299
1300         if (len > DLM_MAX_SOCKET_BUFSIZE ||
1301             len < sizeof(struct dlm_header)) {
1302                 BUILD_BUG_ON(PAGE_SIZE < DLM_MAX_SOCKET_BUFSIZE);
1303                 log_print("failed to allocate a buffer of size %d", len);
1304                 WARN_ON_ONCE(1);
1305                 return NULL;
1306         }
1307
1308         idx = srcu_read_lock(&connections_srcu);
1309         con = nodeid2con(nodeid, 0);
1310         if (WARN_ON_ONCE(!con)) {
1311                 srcu_read_unlock(&connections_srcu, idx);
1312                 return NULL;
1313         }
1314
1315         msg = dlm_lowcomms_new_msg_con(con, len, allocation, ppc, cb, data);
1316         if (!msg) {
1317                 srcu_read_unlock(&connections_srcu, idx);
1318                 return NULL;
1319         }
1320
1321         /* for dlm_lowcomms_commit_msg() */
1322         kref_get(&msg->ref);
1323         /* we assume if successful commit must called */
1324         msg->idx = idx;
1325         return msg;
1326 }
1327 #endif
1328
1329 static void _dlm_lowcomms_commit_msg(struct dlm_msg *msg)
1330 {
1331         struct writequeue_entry *e = msg->entry;
1332         struct connection *con = e->con;
1333         int users;
1334
1335         spin_lock_bh(&con->writequeue_lock);
1336         kref_get(&msg->ref);
1337         list_add(&msg->list, &e->msgs);
1338
1339         users = --e->users;
1340         if (users)
1341                 goto out;
1342
1343         e->len = DLM_WQ_LENGTH_BYTES(e);
1344
1345         lowcomms_queue_swork(con);
1346
1347 out:
1348         spin_unlock_bh(&con->writequeue_lock);
1349         return;
1350 }
1351
1352 /* avoid false positive for nodes_srcu, lock was happen in
1353  * dlm_lowcomms_new_msg
1354  */
1355 #ifndef __CHECKER__
1356 void dlm_lowcomms_commit_msg(struct dlm_msg *msg)
1357 {
1358         _dlm_lowcomms_commit_msg(msg);
1359         srcu_read_unlock(&connections_srcu, msg->idx);
1360         /* because dlm_lowcomms_new_msg() */
1361         kref_put(&msg->ref, dlm_msg_release);
1362 }
1363 #endif
1364
1365 void dlm_lowcomms_put_msg(struct dlm_msg *msg)
1366 {
1367         kref_put(&msg->ref, dlm_msg_release);
1368 }
1369
1370 /* does not held connections_srcu, usage lowcomms_error_report only */
1371 int dlm_lowcomms_resend_msg(struct dlm_msg *msg)
1372 {
1373         struct dlm_msg *msg_resend;
1374         char *ppc;
1375
1376         if (msg->retransmit)
1377                 return 1;
1378
1379         msg_resend = dlm_lowcomms_new_msg_con(msg->entry->con, msg->len,
1380                                               GFP_ATOMIC, &ppc, NULL, NULL);
1381         if (!msg_resend)
1382                 return -ENOMEM;
1383
1384         msg->retransmit = true;
1385         kref_get(&msg->ref);
1386         msg_resend->orig_msg = msg;
1387
1388         memcpy(ppc, msg->ppc, msg->len);
1389         _dlm_lowcomms_commit_msg(msg_resend);
1390         dlm_lowcomms_put_msg(msg_resend);
1391
1392         return 0;
1393 }
1394
1395 /* Send a message */
1396 static int send_to_sock(struct connection *con)
1397 {
1398         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1399         struct writequeue_entry *e;
1400         int len, offset, ret;
1401
1402         spin_lock_bh(&con->writequeue_lock);
1403         e = con_next_wq(con);
1404         if (!e) {
1405                 clear_bit(CF_SEND_PENDING, &con->flags);
1406                 spin_unlock_bh(&con->writequeue_lock);
1407                 return DLM_IO_END;
1408         }
1409
1410         len = e->len;
1411         offset = e->offset;
1412         WARN_ON_ONCE(len == 0 && e->users == 0);
1413         spin_unlock_bh(&con->writequeue_lock);
1414
1415         ret = kernel_sendpage(con->sock, e->page, offset, len,
1416                               msg_flags);
1417         trace_dlm_send(con->nodeid, ret);
1418         if (ret == -EAGAIN || ret == 0) {
1419                 lock_sock(con->sock->sk);
1420                 spin_lock_bh(&con->writequeue_lock);
1421                 if (test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1422                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1423                         /* Notify TCP that we're limited by the
1424                          * application window size.
1425                          */
1426                         set_bit(SOCK_NOSPACE, &con->sock->sk->sk_socket->flags);
1427                         con->sock->sk->sk_write_pending++;
1428
1429                         clear_bit(CF_SEND_PENDING, &con->flags);
1430                         spin_unlock_bh(&con->writequeue_lock);
1431                         release_sock(con->sock->sk);
1432
1433                         /* wait for write_space() event */
1434                         return DLM_IO_END;
1435                 }
1436                 spin_unlock_bh(&con->writequeue_lock);
1437                 release_sock(con->sock->sk);
1438
1439                 return DLM_IO_RESCHED;
1440         } else if (ret < 0) {
1441                 return ret;
1442         }
1443
1444         spin_lock_bh(&con->writequeue_lock);
1445         writequeue_entry_complete(e, ret);
1446         spin_unlock_bh(&con->writequeue_lock);
1447
1448         return DLM_IO_SUCCESS;
1449 }
1450
1451 static void clean_one_writequeue(struct connection *con)
1452 {
1453         struct writequeue_entry *e, *safe;
1454
1455         spin_lock_bh(&con->writequeue_lock);
1456         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1457                 free_entry(e);
1458         }
1459         spin_unlock_bh(&con->writequeue_lock);
1460 }
1461
1462 static void connection_release(struct rcu_head *rcu)
1463 {
1464         struct connection *con = container_of(rcu, struct connection, rcu);
1465
1466         WARN_ON_ONCE(!list_empty(&con->writequeue));
1467         WARN_ON_ONCE(con->sock);
1468         kfree(con);
1469 }
1470
1471 /* Called from recovery when it knows that a node has
1472    left the cluster */
1473 int dlm_lowcomms_close(int nodeid)
1474 {
1475         struct connection *con;
1476         int idx;
1477
1478         log_print("closing connection to node %d", nodeid);
1479
1480         idx = srcu_read_lock(&connections_srcu);
1481         con = nodeid2con(nodeid, 0);
1482         if (WARN_ON_ONCE(!con)) {
1483                 srcu_read_unlock(&connections_srcu, idx);
1484                 return -ENOENT;
1485         }
1486
1487         stop_connection_io(con);
1488         log_print("io handling for node: %d stopped", nodeid);
1489         close_connection(con, true);
1490
1491         spin_lock(&connections_lock);
1492         hlist_del_rcu(&con->list);
1493         spin_unlock(&connections_lock);
1494
1495         clean_one_writequeue(con);
1496         call_srcu(&connections_srcu, &con->rcu, connection_release);
1497         if (con->othercon) {
1498                 clean_one_writequeue(con->othercon);
1499                 if (con->othercon)
1500                         call_srcu(&connections_srcu, &con->othercon->rcu, connection_release);
1501         }
1502         srcu_read_unlock(&connections_srcu, idx);
1503
1504         /* for debugging we print when we are done to compare with other
1505          * messages in between. This function need to be correctly synchronized
1506          * with io handling
1507          */
1508         log_print("closing connection to node %d done", nodeid);
1509
1510         return 0;
1511 }
1512
1513 /* Receive worker function */
1514 static void process_recv_sockets(struct work_struct *work)
1515 {
1516         struct connection *con = container_of(work, struct connection, rwork);
1517         int ret, buflen;
1518
1519         down_read(&con->sock_lock);
1520         if (!con->sock) {
1521                 up_read(&con->sock_lock);
1522                 return;
1523         }
1524
1525         buflen = READ_ONCE(dlm_config.ci_buffer_size);
1526         do {
1527                 ret = receive_from_sock(con, buflen);
1528         } while (ret == DLM_IO_SUCCESS);
1529         up_read(&con->sock_lock);
1530
1531         switch (ret) {
1532         case DLM_IO_END:
1533                 /* CF_RECV_PENDING cleared */
1534                 break;
1535         case DLM_IO_EOF:
1536                 close_connection(con, false);
1537                 wake_up(&con->shutdown_wait);
1538                 /* CF_RECV_PENDING cleared */
1539                 break;
1540         case DLM_IO_RESCHED:
1541                 cond_resched();
1542                 queue_work(io_workqueue, &con->rwork);
1543                 /* CF_RECV_PENDING not cleared */
1544                 break;
1545         default:
1546                 if (ret < 0) {
1547                         if (test_bit(CF_IS_OTHERCON, &con->flags)) {
1548                                 close_connection(con, false);
1549                         } else {
1550                                 spin_lock_bh(&con->writequeue_lock);
1551                                 lowcomms_queue_swork(con);
1552                                 spin_unlock_bh(&con->writequeue_lock);
1553                         }
1554
1555                         /* CF_RECV_PENDING cleared for othercon
1556                          * we trigger send queue if not already done
1557                          * and process_send_sockets will handle it
1558                          */
1559                         break;
1560                 }
1561
1562                 WARN_ON_ONCE(1);
1563                 break;
1564         }
1565 }
1566
1567 static void process_listen_recv_socket(struct work_struct *work)
1568 {
1569         int ret;
1570
1571         if (WARN_ON_ONCE(!listen_con.sock))
1572                 return;
1573
1574         do {
1575                 ret = accept_from_sock();
1576         } while (ret == DLM_IO_SUCCESS);
1577
1578         if (ret < 0)
1579                 log_print("critical error accepting connection: %d", ret);
1580 }
1581
1582 static int dlm_connect(struct connection *con)
1583 {
1584         struct sockaddr_storage addr;
1585         int result, addr_len;
1586         struct socket *sock;
1587         unsigned int mark;
1588
1589         memset(&addr, 0, sizeof(addr));
1590         result = nodeid_to_addr(con->nodeid, &addr, NULL,
1591                                 dlm_proto_ops->try_new_addr, &mark);
1592         if (result < 0) {
1593                 log_print("no address for nodeid %d", con->nodeid);
1594                 return result;
1595         }
1596
1597         /* Create a socket to communicate with */
1598         result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family,
1599                                   SOCK_STREAM, dlm_proto_ops->proto, &sock);
1600         if (result < 0)
1601                 return result;
1602
1603         sock_set_mark(sock->sk, mark);
1604         dlm_proto_ops->sockopts(sock);
1605
1606         result = dlm_proto_ops->bind(sock);
1607         if (result < 0) {
1608                 sock_release(sock);
1609                 return result;
1610         }
1611
1612         add_sock(sock, con);
1613
1614         log_print_ratelimited("connecting to %d", con->nodeid);
1615         make_sockaddr(&addr, dlm_config.ci_tcp_port, &addr_len);
1616         result = dlm_proto_ops->connect(con, sock, (struct sockaddr *)&addr,
1617                                         addr_len);
1618         switch (result) {
1619         case -EINPROGRESS:
1620                 /* not an error */
1621                 fallthrough;
1622         case 0:
1623                 break;
1624         default:
1625                 if (result < 0)
1626                         dlm_close_sock(&con->sock);
1627
1628                 break;
1629         }
1630
1631         return result;
1632 }
1633
1634 /* Send worker function */
1635 static void process_send_sockets(struct work_struct *work)
1636 {
1637         struct connection *con = container_of(work, struct connection, swork);
1638         int ret;
1639
1640         WARN_ON_ONCE(test_bit(CF_IS_OTHERCON, &con->flags));
1641
1642         down_read(&con->sock_lock);
1643         if (!con->sock) {
1644                 up_read(&con->sock_lock);
1645                 down_write(&con->sock_lock);
1646                 if (!con->sock) {
1647                         ret = dlm_connect(con);
1648                         switch (ret) {
1649                         case 0:
1650                                 break;
1651                         case -EINPROGRESS:
1652                                 /* avoid spamming resched on connection
1653                                  * we might can switch to a state_change
1654                                  * event based mechanism if established
1655                                  */
1656                                 msleep(100);
1657                                 break;
1658                         default:
1659                                 /* CF_SEND_PENDING not cleared */
1660                                 up_write(&con->sock_lock);
1661                                 log_print("connect to node %d try %d error %d",
1662                                           con->nodeid, con->retries++, ret);
1663                                 msleep(1000);
1664                                 /* For now we try forever to reconnect. In
1665                                  * future we should send a event to cluster
1666                                  * manager to fence itself after certain amount
1667                                  * of retries.
1668                                  */
1669                                 queue_work(io_workqueue, &con->swork);
1670                                 return;
1671                         }
1672                 }
1673                 downgrade_write(&con->sock_lock);
1674         }
1675
1676         do {
1677                 ret = send_to_sock(con);
1678         } while (ret == DLM_IO_SUCCESS);
1679         up_read(&con->sock_lock);
1680
1681         switch (ret) {
1682         case DLM_IO_END:
1683                 /* CF_SEND_PENDING cleared */
1684                 break;
1685         case DLM_IO_RESCHED:
1686                 /* CF_SEND_PENDING not cleared */
1687                 cond_resched();
1688                 queue_work(io_workqueue, &con->swork);
1689                 break;
1690         default:
1691                 if (ret < 0) {
1692                         close_connection(con, false);
1693
1694                         /* CF_SEND_PENDING cleared */
1695                         spin_lock_bh(&con->writequeue_lock);
1696                         lowcomms_queue_swork(con);
1697                         spin_unlock_bh(&con->writequeue_lock);
1698                         break;
1699                 }
1700
1701                 WARN_ON_ONCE(1);
1702                 break;
1703         }
1704 }
1705
1706 static void work_stop(void)
1707 {
1708         if (io_workqueue) {
1709                 destroy_workqueue(io_workqueue);
1710                 io_workqueue = NULL;
1711         }
1712
1713         if (process_workqueue) {
1714                 destroy_workqueue(process_workqueue);
1715                 process_workqueue = NULL;
1716         }
1717 }
1718
1719 static int work_start(void)
1720 {
1721         io_workqueue = alloc_workqueue("dlm_io", WQ_HIGHPRI | WQ_MEM_RECLAIM,
1722                                        0);
1723         if (!io_workqueue) {
1724                 log_print("can't start dlm_io");
1725                 return -ENOMEM;
1726         }
1727
1728         /* ordered dlm message process queue,
1729          * should be converted to a tasklet
1730          */
1731         process_workqueue = alloc_ordered_workqueue("dlm_process",
1732                                                     WQ_HIGHPRI | WQ_MEM_RECLAIM);
1733         if (!process_workqueue) {
1734                 log_print("can't start dlm_process");
1735                 destroy_workqueue(io_workqueue);
1736                 io_workqueue = NULL;
1737                 return -ENOMEM;
1738         }
1739
1740         return 0;
1741 }
1742
1743 void dlm_lowcomms_shutdown(void)
1744 {
1745         struct connection *con;
1746         int i, idx;
1747
1748         /* stop lowcomms_listen_data_ready calls */
1749         lock_sock(listen_con.sock->sk);
1750         listen_con.sock->sk->sk_data_ready = listen_sock.sk_data_ready;
1751         release_sock(listen_con.sock->sk);
1752
1753         cancel_work_sync(&listen_con.rwork);
1754         dlm_close_sock(&listen_con.sock);
1755
1756         idx = srcu_read_lock(&connections_srcu);
1757         for (i = 0; i < CONN_HASH_SIZE; i++) {
1758                 hlist_for_each_entry_rcu(con, &connection_hash[i], list) {
1759                         shutdown_connection(con, true);
1760                         stop_connection_io(con);
1761                         flush_workqueue(process_workqueue);
1762                         close_connection(con, true);
1763
1764                         clean_one_writequeue(con);
1765                         if (con->othercon)
1766                                 clean_one_writequeue(con->othercon);
1767                         allow_connection_io(con);
1768                 }
1769         }
1770         srcu_read_unlock(&connections_srcu, idx);
1771 }
1772
1773 void dlm_lowcomms_stop(void)
1774 {
1775         work_stop();
1776         dlm_proto_ops = NULL;
1777 }
1778
1779 static int dlm_listen_for_all(void)
1780 {
1781         struct socket *sock;
1782         int result;
1783
1784         log_print("Using %s for communications",
1785                   dlm_proto_ops->name);
1786
1787         result = dlm_proto_ops->listen_validate();
1788         if (result < 0)
1789                 return result;
1790
1791         result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family,
1792                                   SOCK_STREAM, dlm_proto_ops->proto, &sock);
1793         if (result < 0) {
1794                 log_print("Can't create comms socket: %d", result);
1795                 return result;
1796         }
1797
1798         sock_set_mark(sock->sk, dlm_config.ci_mark);
1799         dlm_proto_ops->listen_sockopts(sock);
1800
1801         result = dlm_proto_ops->listen_bind(sock);
1802         if (result < 0)
1803                 goto out;
1804
1805         lock_sock(sock->sk);
1806         listen_sock.sk_data_ready = sock->sk->sk_data_ready;
1807         listen_sock.sk_write_space = sock->sk->sk_write_space;
1808         listen_sock.sk_error_report = sock->sk->sk_error_report;
1809         listen_sock.sk_state_change = sock->sk->sk_state_change;
1810
1811         listen_con.sock = sock;
1812
1813         sock->sk->sk_allocation = GFP_NOFS;
1814         sock->sk->sk_use_task_frag = false;
1815         sock->sk->sk_data_ready = lowcomms_listen_data_ready;
1816         release_sock(sock->sk);
1817
1818         result = sock->ops->listen(sock, 5);
1819         if (result < 0) {
1820                 dlm_close_sock(&listen_con.sock);
1821                 return result;
1822         }
1823
1824         return 0;
1825
1826 out:
1827         sock_release(sock);
1828         return result;
1829 }
1830
1831 static int dlm_tcp_bind(struct socket *sock)
1832 {
1833         struct sockaddr_storage src_addr;
1834         int result, addr_len;
1835
1836         /* Bind to our cluster-known address connecting to avoid
1837          * routing problems.
1838          */
1839         memcpy(&src_addr, &dlm_local_addr[0], sizeof(src_addr));
1840         make_sockaddr(&src_addr, 0, &addr_len);
1841
1842         result = sock->ops->bind(sock, (struct sockaddr *)&src_addr,
1843                                  addr_len);
1844         if (result < 0) {
1845                 /* This *may* not indicate a critical error */
1846                 log_print("could not bind for connect: %d", result);
1847         }
1848
1849         return 0;
1850 }
1851
1852 static int dlm_tcp_connect(struct connection *con, struct socket *sock,
1853                            struct sockaddr *addr, int addr_len)
1854 {
1855         return sock->ops->connect(sock, addr, addr_len, O_NONBLOCK);
1856 }
1857
1858 static int dlm_tcp_listen_validate(void)
1859 {
1860         /* We don't support multi-homed hosts */
1861         if (dlm_local_count > 1) {
1862                 log_print("TCP protocol can't handle multi-homed hosts, try SCTP");
1863                 return -EINVAL;
1864         }
1865
1866         return 0;
1867 }
1868
1869 static void dlm_tcp_sockopts(struct socket *sock)
1870 {
1871         /* Turn off Nagle's algorithm */
1872         tcp_sock_set_nodelay(sock->sk);
1873 }
1874
1875 static void dlm_tcp_listen_sockopts(struct socket *sock)
1876 {
1877         dlm_tcp_sockopts(sock);
1878         sock_set_reuseaddr(sock->sk);
1879 }
1880
1881 static int dlm_tcp_listen_bind(struct socket *sock)
1882 {
1883         int addr_len;
1884
1885         /* Bind to our port */
1886         make_sockaddr(&dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
1887         return sock->ops->bind(sock, (struct sockaddr *)&dlm_local_addr[0],
1888                                addr_len);
1889 }
1890
1891 static const struct dlm_proto_ops dlm_tcp_ops = {
1892         .name = "TCP",
1893         .proto = IPPROTO_TCP,
1894         .connect = dlm_tcp_connect,
1895         .sockopts = dlm_tcp_sockopts,
1896         .bind = dlm_tcp_bind,
1897         .listen_validate = dlm_tcp_listen_validate,
1898         .listen_sockopts = dlm_tcp_listen_sockopts,
1899         .listen_bind = dlm_tcp_listen_bind,
1900 };
1901
1902 static int dlm_sctp_bind(struct socket *sock)
1903 {
1904         return sctp_bind_addrs(sock, 0);
1905 }
1906
1907 static int dlm_sctp_connect(struct connection *con, struct socket *sock,
1908                             struct sockaddr *addr, int addr_len)
1909 {
1910         int ret;
1911
1912         /*
1913          * Make sock->ops->connect() function return in specified time,
1914          * since O_NONBLOCK argument in connect() function does not work here,
1915          * then, we should restore the default value of this attribute.
1916          */
1917         sock_set_sndtimeo(sock->sk, 5);
1918         ret = sock->ops->connect(sock, addr, addr_len, 0);
1919         sock_set_sndtimeo(sock->sk, 0);
1920         return ret;
1921 }
1922
1923 static int dlm_sctp_listen_validate(void)
1924 {
1925         if (!IS_ENABLED(CONFIG_IP_SCTP)) {
1926                 log_print("SCTP is not enabled by this kernel");
1927                 return -EOPNOTSUPP;
1928         }
1929
1930         request_module("sctp");
1931         return 0;
1932 }
1933
1934 static int dlm_sctp_bind_listen(struct socket *sock)
1935 {
1936         return sctp_bind_addrs(sock, dlm_config.ci_tcp_port);
1937 }
1938
1939 static void dlm_sctp_sockopts(struct socket *sock)
1940 {
1941         /* Turn off Nagle's algorithm */
1942         sctp_sock_set_nodelay(sock->sk);
1943         sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
1944 }
1945
1946 static const struct dlm_proto_ops dlm_sctp_ops = {
1947         .name = "SCTP",
1948         .proto = IPPROTO_SCTP,
1949         .try_new_addr = true,
1950         .connect = dlm_sctp_connect,
1951         .sockopts = dlm_sctp_sockopts,
1952         .bind = dlm_sctp_bind,
1953         .listen_validate = dlm_sctp_listen_validate,
1954         .listen_sockopts = dlm_sctp_sockopts,
1955         .listen_bind = dlm_sctp_bind_listen,
1956 };
1957
1958 int dlm_lowcomms_start(void)
1959 {
1960         int error;
1961
1962         init_local();
1963         if (!dlm_local_count) {
1964                 error = -ENOTCONN;
1965                 log_print("no local IP address has been set");
1966                 goto fail;
1967         }
1968
1969         error = work_start();
1970         if (error)
1971                 goto fail;
1972
1973         /* Start listening */
1974         switch (dlm_config.ci_protocol) {
1975         case DLM_PROTO_TCP:
1976                 dlm_proto_ops = &dlm_tcp_ops;
1977                 break;
1978         case DLM_PROTO_SCTP:
1979                 dlm_proto_ops = &dlm_sctp_ops;
1980                 break;
1981         default:
1982                 log_print("Invalid protocol identifier %d set",
1983                           dlm_config.ci_protocol);
1984                 error = -EINVAL;
1985                 goto fail_proto_ops;
1986         }
1987
1988         error = dlm_listen_for_all();
1989         if (error)
1990                 goto fail_listen;
1991
1992         return 0;
1993
1994 fail_listen:
1995         dlm_proto_ops = NULL;
1996 fail_proto_ops:
1997         work_stop();
1998 fail:
1999         return error;
2000 }
2001
2002 void dlm_lowcomms_init(void)
2003 {
2004         int i;
2005
2006         for (i = 0; i < CONN_HASH_SIZE; i++)
2007                 INIT_HLIST_HEAD(&connection_hash[i]);
2008
2009         INIT_WORK(&listen_con.rwork, process_listen_recv_socket);
2010 }
2011
2012 void dlm_lowcomms_exit(void)
2013 {
2014         struct connection *con;
2015         int i, idx;
2016
2017         idx = srcu_read_lock(&connections_srcu);
2018         for (i = 0; i < CONN_HASH_SIZE; i++) {
2019                 hlist_for_each_entry_rcu(con, &connection_hash[i], list) {
2020                         spin_lock(&connections_lock);
2021                         hlist_del_rcu(&con->list);
2022                         spin_unlock(&connections_lock);
2023
2024                         if (con->othercon)
2025                                 call_srcu(&connections_srcu, &con->othercon->rcu,
2026                                           connection_release);
2027                         call_srcu(&connections_srcu, &con->rcu, connection_release);
2028                 }
2029         }
2030         srcu_read_unlock(&connections_srcu, idx);
2031 }