1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *
   4 * Copyright (C) 2004 Oracle.  All rights reserved.
   5 *
   6 * ----
   7 *
   8 * Callers for this were originally written against a very simple synchronus
   9 * API.  This implementation reflects those simple callers.  Some day I'm sure
  10 * we'll need to move to a more robust posting/callback mechanism.
  11 *
  12 * Transmit calls pass in kernel virtual addresses and block copying this into
  13 * the socket's tx buffers via a usual blocking sendmsg.  They'll block waiting
  14 * for a failed socket to timeout.  TX callers can also pass in a poniter to an
  15 * 'int' which gets filled with an errno off the wire in response to the
  16 * message they send.
  17 *
  18 * Handlers for unsolicited messages are registered.  Each socket has a page
  19 * that incoming data is copied into.  First the header, then the data.
  20 * Handlers are called from only one thread with a reference to this per-socket
  21 * page.  This page is destroyed after the handler call, so it can't be
  22 * referenced beyond the call.  Handlers may block but are discouraged from
  23 * doing so.
  24 *
  25 * Any framing errors (bad magic, large payload lengths) close a connection.
  26 *
  27 * Our sock_container holds the state we associate with a socket.  It's current
  28 * framing state is held there as well as the refcounting we do around when it
  29 * is safe to tear down the socket.  The socket is only finally torn down from
  30 * the container when the container loses all of its references -- so as long
  31 * as you hold a ref on the container you can trust that the socket is valid
  32 * for use with kernel socket APIs.
  33 *
  34 * Connections are initiated between a pair of nodes when the node with the
  35 * higher node number gets a heartbeat callback which indicates that the lower
  36 * numbered node has started heartbeating.  The lower numbered node is passive
  37 * and only accepts the connection if the higher numbered node is heartbeating.
  38 */
  39
  40#include <linux/kernel.h>
  41#include <linux/sched/mm.h>
  42#include <linux/jiffies.h>
  43#include <linux/slab.h>
  44#include <linux/idr.h>
  45#include <linux/kref.h>
  46#include <linux/net.h>
  47#include <linux/export.h>
  48#include <net/tcp.h>
 
  49
  50#include <linux/uaccess.h>
  51
  52#include "heartbeat.h"
  53#include "tcp.h"
  54#include "nodemanager.h"
  55#define MLOG_MASK_PREFIX ML_TCP
  56#include "masklog.h"
  57#include "quorum.h"
  58
  59#include "tcp_internal.h"
  60
  61#define SC_NODEF_FMT "node %s (num %u) at %pI4:%u"
  62#define SC_NODEF_ARGS(sc) sc->sc_node->nd_name, sc->sc_node->nd_num,	\
  63			  &sc->sc_node->nd_ipv4_address,		\
  64			  ntohs(sc->sc_node->nd_ipv4_port)
  65
  66/*
  67 * In the following two log macros, the whitespace after the ',' just
  68 * before ##args is intentional. Otherwise, gcc 2.95 will eat the
  69 * previous token if args expands to nothing.
  70 */
  71#define msglog(hdr, fmt, args...) do {					\
  72	typeof(hdr) __hdr = (hdr);					\
  73	mlog(ML_MSG, "[mag %u len %u typ %u stat %d sys_stat %d "	\
  74	     "key %08x num %u] " fmt,					\
  75	     be16_to_cpu(__hdr->magic), be16_to_cpu(__hdr->data_len), 	\
  76	     be16_to_cpu(__hdr->msg_type), be32_to_cpu(__hdr->status),	\
  77	     be32_to_cpu(__hdr->sys_status), be32_to_cpu(__hdr->key),	\
  78	     be32_to_cpu(__hdr->msg_num) ,  ##args);			\
  79} while (0)
  80
  81#define sclog(sc, fmt, args...) do {					\
  82	typeof(sc) __sc = (sc);						\
  83	mlog(ML_SOCKET, "[sc %p refs %d sock %p node %u page %p "	\
  84	     "pg_off %zu] " fmt, __sc,					\
  85	     kref_read(&__sc->sc_kref), __sc->sc_sock,	\
  86	    __sc->sc_node->nd_num, __sc->sc_page, __sc->sc_page_off ,	\
  87	    ##args);							\
  88} while (0)
  89
  90static DEFINE_RWLOCK(o2net_handler_lock);
  91static struct rb_root o2net_handler_tree = RB_ROOT;
  92
  93static struct o2net_node o2net_nodes[O2NM_MAX_NODES];
  94
  95/* XXX someday we'll need better accounting */
  96static struct socket *o2net_listen_sock;
  97
  98/*
  99 * listen work is only queued by the listening socket callbacks on the
 100 * o2net_wq.  teardown detaches the callbacks before destroying the workqueue.
 101 * quorum work is queued as sock containers are shutdown.. stop_listening
 102 * tears down all the node's sock containers, preventing future shutdowns
 103 * and queued quroum work, before canceling delayed quorum work and
 104 * destroying the work queue.
 105 */
 106static struct workqueue_struct *o2net_wq;
 107static struct work_struct o2net_listen_work;
 108
 109static struct o2hb_callback_func o2net_hb_up, o2net_hb_down;
 110#define O2NET_HB_PRI 0x1
 111
 112static struct o2net_handshake *o2net_hand;
 113static struct o2net_msg *o2net_keep_req, *o2net_keep_resp;
 114
 115static int o2net_sys_err_translations[O2NET_ERR_MAX] =
 116		{[O2NET_ERR_NONE]	= 0,
 117		 [O2NET_ERR_NO_HNDLR]	= -ENOPROTOOPT,
 118		 [O2NET_ERR_OVERFLOW]	= -EOVERFLOW,
 119		 [O2NET_ERR_DIED]	= -EHOSTDOWN,};
 120
 121/* can't quite avoid *all* internal declarations :/ */
 122static void o2net_sc_connect_completed(struct work_struct *work);
 123static void o2net_rx_until_empty(struct work_struct *work);
 124static void o2net_shutdown_sc(struct work_struct *work);
 125static void o2net_listen_data_ready(struct sock *sk);
 126static void o2net_sc_send_keep_req(struct work_struct *work);
 127static void o2net_idle_timer(struct timer_list *t);
 128static void o2net_sc_postpone_idle(struct o2net_sock_container *sc);
 129static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc);
 130
 131#ifdef CONFIG_DEBUG_FS
 132static void o2net_init_nst(struct o2net_send_tracking *nst, u32 msgtype,
 133			   u32 msgkey, struct task_struct *task, u8 node)
 134{
 135	INIT_LIST_HEAD(&nst->st_net_debug_item);
 136	nst->st_task = task;
 137	nst->st_msg_type = msgtype;
 138	nst->st_msg_key = msgkey;
 139	nst->st_node = node;
 140}
 141
 142static inline void o2net_set_nst_sock_time(struct o2net_send_tracking *nst)
 143{
 144	nst->st_sock_time = ktime_get();
 145}
 146
 147static inline void o2net_set_nst_send_time(struct o2net_send_tracking *nst)
 148{
 149	nst->st_send_time = ktime_get();
 150}
 151
 152static inline void o2net_set_nst_status_time(struct o2net_send_tracking *nst)
 153{
 154	nst->st_status_time = ktime_get();
 155}
 156
 157static inline void o2net_set_nst_sock_container(struct o2net_send_tracking *nst,
 158						struct o2net_sock_container *sc)
 159{
 160	nst->st_sc = sc;
 161}
 162
 163static inline void o2net_set_nst_msg_id(struct o2net_send_tracking *nst,
 164					u32 msg_id)
 165{
 166	nst->st_id = msg_id;
 167}
 168
 169static inline void o2net_set_sock_timer(struct o2net_sock_container *sc)
 170{
 171	sc->sc_tv_timer = ktime_get();
 172}
 173
 174static inline void o2net_set_data_ready_time(struct o2net_sock_container *sc)
 175{
 176	sc->sc_tv_data_ready = ktime_get();
 177}
 178
 179static inline void o2net_set_advance_start_time(struct o2net_sock_container *sc)
 180{
 181	sc->sc_tv_advance_start = ktime_get();
 182}
 183
 184static inline void o2net_set_advance_stop_time(struct o2net_sock_container *sc)
 185{
 186	sc->sc_tv_advance_stop = ktime_get();
 187}
 188
 189static inline void o2net_set_func_start_time(struct o2net_sock_container *sc)
 190{
 191	sc->sc_tv_func_start = ktime_get();
 192}
 193
 194static inline void o2net_set_func_stop_time(struct o2net_sock_container *sc)
 195{
 196	sc->sc_tv_func_stop = ktime_get();
 197}
 198
 199#else  /* CONFIG_DEBUG_FS */
 200# define o2net_init_nst(a, b, c, d, e)
 201# define o2net_set_nst_sock_time(a)
 202# define o2net_set_nst_send_time(a)
 203# define o2net_set_nst_status_time(a)
 204# define o2net_set_nst_sock_container(a, b)
 205# define o2net_set_nst_msg_id(a, b)
 206# define o2net_set_sock_timer(a)
 207# define o2net_set_data_ready_time(a)
 208# define o2net_set_advance_start_time(a)
 209# define o2net_set_advance_stop_time(a)
 210# define o2net_set_func_start_time(a)
 211# define o2net_set_func_stop_time(a)
 212#endif /* CONFIG_DEBUG_FS */
 213
 214#ifdef CONFIG_OCFS2_FS_STATS
 215static ktime_t o2net_get_func_run_time(struct o2net_sock_container *sc)
 216{
 217	return ktime_sub(sc->sc_tv_func_stop, sc->sc_tv_func_start);
 218}
 219
 220static void o2net_update_send_stats(struct o2net_send_tracking *nst,
 221				    struct o2net_sock_container *sc)
 222{
 223	sc->sc_tv_status_total = ktime_add(sc->sc_tv_status_total,
 224					   ktime_sub(ktime_get(),
 225						     nst->st_status_time));
 226	sc->sc_tv_send_total = ktime_add(sc->sc_tv_send_total,
 227					 ktime_sub(nst->st_status_time,
 228						   nst->st_send_time));
 229	sc->sc_tv_acquiry_total = ktime_add(sc->sc_tv_acquiry_total,
 230					    ktime_sub(nst->st_send_time,
 231						      nst->st_sock_time));
 232	sc->sc_send_count++;
 233}
 234
 235static void o2net_update_recv_stats(struct o2net_sock_container *sc)
 236{
 237	sc->sc_tv_process_total = ktime_add(sc->sc_tv_process_total,
 238					    o2net_get_func_run_time(sc));
 239	sc->sc_recv_count++;
 240}
 241
 242#else
 243
 244# define o2net_update_send_stats(a, b)
 245
 246# define o2net_update_recv_stats(sc)
 247
 248#endif /* CONFIG_OCFS2_FS_STATS */
 249
 250static inline unsigned int o2net_reconnect_delay(void)
 251{
 252	return o2nm_single_cluster->cl_reconnect_delay_ms;
 253}
 254
 255static inline unsigned int o2net_keepalive_delay(void)
 256{
 257	return o2nm_single_cluster->cl_keepalive_delay_ms;
 258}
 259
 260static inline unsigned int o2net_idle_timeout(void)
 261{
 262	return o2nm_single_cluster->cl_idle_timeout_ms;
 263}
 264
 265static inline int o2net_sys_err_to_errno(enum o2net_system_error err)
 266{
 267	int trans;
 268	BUG_ON(err >= O2NET_ERR_MAX);
 269	trans = o2net_sys_err_translations[err];
 270
 271	/* Just in case we mess up the translation table above */
 272	BUG_ON(err != O2NET_ERR_NONE && trans == 0);
 273	return trans;
 274}
 275
 276static struct o2net_node * o2net_nn_from_num(u8 node_num)
 277{
 278	BUG_ON(node_num >= ARRAY_SIZE(o2net_nodes));
 279	return &o2net_nodes[node_num];
 280}
 281
 282static u8 o2net_num_from_nn(struct o2net_node *nn)
 283{
 284	BUG_ON(nn == NULL);
 285	return nn - o2net_nodes;
 286}
 287
 288/* ------------------------------------------------------------ */
 289
 290static int o2net_prep_nsw(struct o2net_node *nn, struct o2net_status_wait *nsw)
 291{
 292	int ret;
 293
 294	spin_lock(&nn->nn_lock);
 295	ret = idr_alloc(&nn->nn_status_idr, nsw, 0, 0, GFP_ATOMIC);
 296	if (ret >= 0) {
 297		nsw->ns_id = ret;
 298		list_add_tail(&nsw->ns_node_item, &nn->nn_status_list);
 299	}
 300	spin_unlock(&nn->nn_lock);
 301	if (ret < 0)
 302		return ret;
 303
 304	init_waitqueue_head(&nsw->ns_wq);
 305	nsw->ns_sys_status = O2NET_ERR_NONE;
 306	nsw->ns_status = 0;
 307	return 0;
 308}
 309
 310static void o2net_complete_nsw_locked(struct o2net_node *nn,
 311				      struct o2net_status_wait *nsw,
 312				      enum o2net_system_error sys_status,
 313				      s32 status)
 314{
 315	assert_spin_locked(&nn->nn_lock);
 316
 317	if (!list_empty(&nsw->ns_node_item)) {
 318		list_del_init(&nsw->ns_node_item);
 319		nsw->ns_sys_status = sys_status;
 320		nsw->ns_status = status;
 321		idr_remove(&nn->nn_status_idr, nsw->ns_id);
 322		wake_up(&nsw->ns_wq);
 323	}
 324}
 325
 326static void o2net_complete_nsw(struct o2net_node *nn,
 327			       struct o2net_status_wait *nsw,
 328			       u64 id, enum o2net_system_error sys_status,
 329			       s32 status)
 330{
 331	spin_lock(&nn->nn_lock);
 332	if (nsw == NULL) {
 333		if (id > INT_MAX)
 334			goto out;
 335
 336		nsw = idr_find(&nn->nn_status_idr, id);
 337		if (nsw == NULL)
 338			goto out;
 339	}
 340
 341	o2net_complete_nsw_locked(nn, nsw, sys_status, status);
 342
 343out:
 344	spin_unlock(&nn->nn_lock);
 345	return;
 346}
 347
 348static void o2net_complete_nodes_nsw(struct o2net_node *nn)
 349{
 350	struct o2net_status_wait *nsw, *tmp;
 351	unsigned int num_kills = 0;
 352
 353	assert_spin_locked(&nn->nn_lock);
 354
 355	list_for_each_entry_safe(nsw, tmp, &nn->nn_status_list, ns_node_item) {
 356		o2net_complete_nsw_locked(nn, nsw, O2NET_ERR_DIED, 0);
 357		num_kills++;
 358	}
 359
 360	mlog(0, "completed %d messages for node %u\n", num_kills,
 361	     o2net_num_from_nn(nn));
 362}
 363
 364static int o2net_nsw_completed(struct o2net_node *nn,
 365			       struct o2net_status_wait *nsw)
 366{
 367	int completed;
 368	spin_lock(&nn->nn_lock);
 369	completed = list_empty(&nsw->ns_node_item);
 370	spin_unlock(&nn->nn_lock);
 371	return completed;
 372}
 373
 374/* ------------------------------------------------------------ */
 375
 376static void sc_kref_release(struct kref *kref)
 377{
 378	struct o2net_sock_container *sc = container_of(kref,
 379					struct o2net_sock_container, sc_kref);
 380	BUG_ON(timer_pending(&sc->sc_idle_timeout));
 381
 382	sclog(sc, "releasing\n");
 383
 384	if (sc->sc_sock) {
 385		sock_release(sc->sc_sock);
 386		sc->sc_sock = NULL;
 387	}
 388
 389	o2nm_undepend_item(&sc->sc_node->nd_item);
 390	o2nm_node_put(sc->sc_node);
 391	sc->sc_node = NULL;
 392
 393	o2net_debug_del_sc(sc);
 394
 395	if (sc->sc_page)
 396		__free_page(sc->sc_page);
 397	kfree(sc);
 398}
 399
 400static void sc_put(struct o2net_sock_container *sc)
 401{
 402	sclog(sc, "put\n");
 403	kref_put(&sc->sc_kref, sc_kref_release);
 404}
 405static void sc_get(struct o2net_sock_container *sc)
 406{
 407	sclog(sc, "get\n");
 408	kref_get(&sc->sc_kref);
 409}
 410static struct o2net_sock_container *sc_alloc(struct o2nm_node *node)
 411{
 412	struct o2net_sock_container *sc, *ret = NULL;
 413	struct page *page = NULL;
 414	int status = 0;
 415
 416	page = alloc_page(GFP_NOFS);
 417	sc = kzalloc(sizeof(*sc), GFP_NOFS);
 418	if (sc == NULL || page == NULL)
 419		goto out;
 420
 421	kref_init(&sc->sc_kref);
 422	o2nm_node_get(node);
 423	sc->sc_node = node;
 424
 425	/* pin the node item of the remote node */
 426	status = o2nm_depend_item(&node->nd_item);
 427	if (status) {
 428		mlog_errno(status);
 429		o2nm_node_put(node);
 430		goto out;
 431	}
 432	INIT_WORK(&sc->sc_connect_work, o2net_sc_connect_completed);
 433	INIT_WORK(&sc->sc_rx_work, o2net_rx_until_empty);
 434	INIT_WORK(&sc->sc_shutdown_work, o2net_shutdown_sc);
 435	INIT_DELAYED_WORK(&sc->sc_keepalive_work, o2net_sc_send_keep_req);
 436
 437	timer_setup(&sc->sc_idle_timeout, o2net_idle_timer, 0);
 438
 439	sclog(sc, "alloced\n");
 440
 441	ret = sc;
 442	sc->sc_page = page;
 443	o2net_debug_add_sc(sc);
 444	sc = NULL;
 445	page = NULL;
 446
 447out:
 448	if (page)
 449		__free_page(page);
 450	kfree(sc);
 451
 452	return ret;
 453}
 454
 455/* ------------------------------------------------------------ */
 456
 457static void o2net_sc_queue_work(struct o2net_sock_container *sc,
 458				struct work_struct *work)
 459{
 460	sc_get(sc);
 461	if (!queue_work(o2net_wq, work))
 462		sc_put(sc);
 463}
 464static void o2net_sc_queue_delayed_work(struct o2net_sock_container *sc,
 465					struct delayed_work *work,
 466					int delay)
 467{
 468	sc_get(sc);
 469	if (!queue_delayed_work(o2net_wq, work, delay))
 470		sc_put(sc);
 471}
 472static void o2net_sc_cancel_delayed_work(struct o2net_sock_container *sc,
 473					 struct delayed_work *work)
 474{
 475	if (cancel_delayed_work(work))
 476		sc_put(sc);
 477}
 478
 479static atomic_t o2net_connected_peers = ATOMIC_INIT(0);
 480
 481int o2net_num_connected_peers(void)
 482{
 483	return atomic_read(&o2net_connected_peers);
 484}
 485
 486static void o2net_set_nn_state(struct o2net_node *nn,
 487			       struct o2net_sock_container *sc,
 488			       unsigned valid, int err)
 489{
 490	int was_valid = nn->nn_sc_valid;
 491	int was_err = nn->nn_persistent_error;
 492	struct o2net_sock_container *old_sc = nn->nn_sc;
 493
 494	assert_spin_locked(&nn->nn_lock);
 495
 496	if (old_sc && !sc)
 497		atomic_dec(&o2net_connected_peers);
 498	else if (!old_sc && sc)
 499		atomic_inc(&o2net_connected_peers);
 500
 501	/* the node num comparison and single connect/accept path should stop
 502	 * an non-null sc from being overwritten with another */
 503	BUG_ON(sc && nn->nn_sc && nn->nn_sc != sc);
 504	mlog_bug_on_msg(err && valid, "err %d valid %u\n", err, valid);
 505	mlog_bug_on_msg(valid && !sc, "valid %u sc %p\n", valid, sc);
 506
 507	if (was_valid && !valid && err == 0)
 508		err = -ENOTCONN;
 509
 510	mlog(ML_CONN, "node %u sc: %p -> %p, valid %u -> %u, err %d -> %d\n",
 511	     o2net_num_from_nn(nn), nn->nn_sc, sc, nn->nn_sc_valid, valid,
 512	     nn->nn_persistent_error, err);
 513
 514	nn->nn_sc = sc;
 515	nn->nn_sc_valid = valid ? 1 : 0;
 516	nn->nn_persistent_error = err;
 517
 518	/* mirrors o2net_tx_can_proceed() */
 519	if (nn->nn_persistent_error || nn->nn_sc_valid)
 520		wake_up(&nn->nn_sc_wq);
 521
 522	if (was_valid && !was_err && nn->nn_persistent_error) {
 523		o2quo_conn_err(o2net_num_from_nn(nn));
 524		queue_delayed_work(o2net_wq, &nn->nn_still_up,
 525				   msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
 526	}
 527
 528	if (was_valid && !valid) {
 529		if (old_sc)
 530			printk(KERN_NOTICE "o2net: No longer connected to "
 531				SC_NODEF_FMT "\n", SC_NODEF_ARGS(old_sc));
 532		o2net_complete_nodes_nsw(nn);
 533	}
 534
 535	if (!was_valid && valid) {
 536		o2quo_conn_up(o2net_num_from_nn(nn));
 537		cancel_delayed_work(&nn->nn_connect_expired);
 538		printk(KERN_NOTICE "o2net: %s " SC_NODEF_FMT "\n",
 539		       o2nm_this_node() > sc->sc_node->nd_num ?
 540		       "Connected to" : "Accepted connection from",
 541		       SC_NODEF_ARGS(sc));
 542	}
 543
 544	/* trigger the connecting worker func as long as we're not valid,
 545	 * it will back off if it shouldn't connect.  This can be called
 546	 * from node config teardown and so needs to be careful about
 547	 * the work queue actually being up. */
 548	if (!valid && o2net_wq) {
 549		unsigned long delay;
 550		/* delay if we're within a RECONNECT_DELAY of the
 551		 * last attempt */
 552		delay = (nn->nn_last_connect_attempt +
 553			 msecs_to_jiffies(o2net_reconnect_delay()))
 554			- jiffies;
 555		if (delay > msecs_to_jiffies(o2net_reconnect_delay()))
 556			delay = 0;
 557		mlog(ML_CONN, "queueing conn attempt in %lu jiffies\n", delay);
 558		queue_delayed_work(o2net_wq, &nn->nn_connect_work, delay);
 559
 560		/*
 561		 * Delay the expired work after idle timeout.
 562		 *
 563		 * We might have lots of failed connection attempts that run
 564		 * through here but we only cancel the connect_expired work when
 565		 * a connection attempt succeeds.  So only the first enqueue of
 566		 * the connect_expired work will do anything.  The rest will see
 567		 * that it's already queued and do nothing.
 568		 */
 569		delay += msecs_to_jiffies(o2net_idle_timeout());
 570		queue_delayed_work(o2net_wq, &nn->nn_connect_expired, delay);
 571	}
 572
 573	/* keep track of the nn's sc ref for the caller */
 574	if ((old_sc == NULL) && sc)
 575		sc_get(sc);
 576	if (old_sc && (old_sc != sc)) {
 577		o2net_sc_queue_work(old_sc, &old_sc->sc_shutdown_work);
 578		sc_put(old_sc);
 579	}
 580}
 581
 582/* see o2net_register_callbacks() */
 583static void o2net_data_ready(struct sock *sk)
 584{
 585	void (*ready)(struct sock *sk);
 586	struct o2net_sock_container *sc;
 587
 
 
 588	read_lock_bh(&sk->sk_callback_lock);
 589	sc = sk->sk_user_data;
 590	if (sc) {
 591		sclog(sc, "data_ready hit\n");
 592		o2net_set_data_ready_time(sc);
 593		o2net_sc_queue_work(sc, &sc->sc_rx_work);
 594		ready = sc->sc_data_ready;
 595	} else {
 596		ready = sk->sk_data_ready;
 597	}
 598	read_unlock_bh(&sk->sk_callback_lock);
 599
 600	ready(sk);
 601}
 602
 603/* see o2net_register_callbacks() */
 604static void o2net_state_change(struct sock *sk)
 605{
 606	void (*state_change)(struct sock *sk);
 607	struct o2net_sock_container *sc;
 608
 609	read_lock_bh(&sk->sk_callback_lock);
 610	sc = sk->sk_user_data;
 611	if (sc == NULL) {
 612		state_change = sk->sk_state_change;
 613		goto out;
 614	}
 615
 616	sclog(sc, "state_change to %d\n", sk->sk_state);
 617
 618	state_change = sc->sc_state_change;
 619
 620	switch(sk->sk_state) {
 621	/* ignore connecting sockets as they make progress */
 622	case TCP_SYN_SENT:
 623	case TCP_SYN_RECV:
 624		break;
 625	case TCP_ESTABLISHED:
 626		o2net_sc_queue_work(sc, &sc->sc_connect_work);
 627		break;
 628	default:
 629		printk(KERN_INFO "o2net: Connection to " SC_NODEF_FMT
 630			" shutdown, state %d\n",
 631			SC_NODEF_ARGS(sc), sk->sk_state);
 632		o2net_sc_queue_work(sc, &sc->sc_shutdown_work);
 633		break;
 634	}
 635out:
 636	read_unlock_bh(&sk->sk_callback_lock);
 637	state_change(sk);
 638}
 639
 640/*
 641 * we register callbacks so we can queue work on events before calling
 642 * the original callbacks.  our callbacks our careful to test user_data
 643 * to discover when they've reaced with o2net_unregister_callbacks().
 644 */
 645static void o2net_register_callbacks(struct sock *sk,
 646				     struct o2net_sock_container *sc)
 647{
 648	write_lock_bh(&sk->sk_callback_lock);
 649
 650	/* accepted sockets inherit the old listen socket data ready */
 651	if (sk->sk_data_ready == o2net_listen_data_ready) {
 652		sk->sk_data_ready = sk->sk_user_data;
 653		sk->sk_user_data = NULL;
 654	}
 655
 656	BUG_ON(sk->sk_user_data != NULL);
 657	sk->sk_user_data = sc;
 658	sc_get(sc);
 659
 660	sc->sc_data_ready = sk->sk_data_ready;
 661	sc->sc_state_change = sk->sk_state_change;
 662	sk->sk_data_ready = o2net_data_ready;
 663	sk->sk_state_change = o2net_state_change;
 664
 665	mutex_init(&sc->sc_send_lock);
 666
 667	write_unlock_bh(&sk->sk_callback_lock);
 668}
 669
 670static int o2net_unregister_callbacks(struct sock *sk,
 671			           struct o2net_sock_container *sc)
 672{
 673	int ret = 0;
 674
 675	write_lock_bh(&sk->sk_callback_lock);
 676	if (sk->sk_user_data == sc) {
 677		ret = 1;
 678		sk->sk_user_data = NULL;
 679		sk->sk_data_ready = sc->sc_data_ready;
 680		sk->sk_state_change = sc->sc_state_change;
 681	}
 682	write_unlock_bh(&sk->sk_callback_lock);
 683
 684	return ret;
 685}
 686
 687/*
 688 * this is a little helper that is called by callers who have seen a problem
 689 * with an sc and want to detach it from the nn if someone already hasn't beat
 690 * them to it.  if an error is given then the shutdown will be persistent
 691 * and pending transmits will be canceled.
 692 */
 693static void o2net_ensure_shutdown(struct o2net_node *nn,
 694			           struct o2net_sock_container *sc,
 695				   int err)
 696{
 697	spin_lock(&nn->nn_lock);
 698	if (nn->nn_sc == sc)
 699		o2net_set_nn_state(nn, NULL, 0, err);
 700	spin_unlock(&nn->nn_lock);
 701}
 702
 703/*
 704 * This work queue function performs the blocking parts of socket shutdown.  A
 705 * few paths lead here.  set_nn_state will trigger this callback if it sees an
 706 * sc detached from the nn.  state_change will also trigger this callback
 707 * directly when it sees errors.  In that case we need to call set_nn_state
 708 * ourselves as state_change couldn't get the nn_lock and call set_nn_state
 709 * itself.
 710 */
 711static void o2net_shutdown_sc(struct work_struct *work)
 712{
 713	struct o2net_sock_container *sc =
 714		container_of(work, struct o2net_sock_container,
 715			     sc_shutdown_work);
 716	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 717
 718	sclog(sc, "shutting down\n");
 719
 720	/* drop the callbacks ref and call shutdown only once */
 721	if (o2net_unregister_callbacks(sc->sc_sock->sk, sc)) {
 722		/* we shouldn't flush as we're in the thread, the
 723		 * races with pending sc work structs are harmless */
 724		del_timer_sync(&sc->sc_idle_timeout);
 725		o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
 726		sc_put(sc);
 727		kernel_sock_shutdown(sc->sc_sock, SHUT_RDWR);
 728	}
 729
 730	/* not fatal so failed connects before the other guy has our
 731	 * heartbeat can be retried */
 732	o2net_ensure_shutdown(nn, sc, 0);
 733	sc_put(sc);
 734}
 735
 736/* ------------------------------------------------------------ */
 737
 738static int o2net_handler_cmp(struct o2net_msg_handler *nmh, u32 msg_type,
 739			     u32 key)
 740{
 741	int ret = memcmp(&nmh->nh_key, &key, sizeof(key));
 742
 743	if (ret == 0)
 744		ret = memcmp(&nmh->nh_msg_type, &msg_type, sizeof(msg_type));
 745
 746	return ret;
 747}
 748
 749static struct o2net_msg_handler *
 750o2net_handler_tree_lookup(u32 msg_type, u32 key, struct rb_node ***ret_p,
 751			  struct rb_node **ret_parent)
 752{
 753	struct rb_node **p = &o2net_handler_tree.rb_node;
 754	struct rb_node *parent = NULL;
 755	struct o2net_msg_handler *nmh, *ret = NULL;
 756	int cmp;
 757
 758	while (*p) {
 759		parent = *p;
 760		nmh = rb_entry(parent, struct o2net_msg_handler, nh_node);
 761		cmp = o2net_handler_cmp(nmh, msg_type, key);
 762
 763		if (cmp < 0)
 764			p = &(*p)->rb_left;
 765		else if (cmp > 0)
 766			p = &(*p)->rb_right;
 767		else {
 768			ret = nmh;
 769			break;
 770		}
 771	}
 772
 773	if (ret_p != NULL)
 774		*ret_p = p;
 775	if (ret_parent != NULL)
 776		*ret_parent = parent;
 777
 778	return ret;
 779}
 780
 781static void o2net_handler_kref_release(struct kref *kref)
 782{
 783	struct o2net_msg_handler *nmh;
 784	nmh = container_of(kref, struct o2net_msg_handler, nh_kref);
 785
 786	kfree(nmh);
 787}
 788
 789static void o2net_handler_put(struct o2net_msg_handler *nmh)
 790{
 791	kref_put(&nmh->nh_kref, o2net_handler_kref_release);
 792}
 793
 794/* max_len is protection for the handler func.  incoming messages won't
 795 * be given to the handler if their payload is longer than the max. */
 796int o2net_register_handler(u32 msg_type, u32 key, u32 max_len,
 797			   o2net_msg_handler_func *func, void *data,
 798			   o2net_post_msg_handler_func *post_func,
 799			   struct list_head *unreg_list)
 800{
 801	struct o2net_msg_handler *nmh = NULL;
 802	struct rb_node **p, *parent;
 803	int ret = 0;
 804
 805	if (max_len > O2NET_MAX_PAYLOAD_BYTES) {
 806		mlog(0, "max_len for message handler out of range: %u\n",
 807			max_len);
 808		ret = -EINVAL;
 809		goto out;
 810	}
 811
 812	if (!msg_type) {
 813		mlog(0, "no message type provided: %u, %p\n", msg_type, func);
 814		ret = -EINVAL;
 815		goto out;
 816
 817	}
 818	if (!func) {
 819		mlog(0, "no message handler provided: %u, %p\n",
 820		       msg_type, func);
 821		ret = -EINVAL;
 822		goto out;
 823	}
 824
 825       	nmh = kzalloc(sizeof(struct o2net_msg_handler), GFP_NOFS);
 826	if (nmh == NULL) {
 827		ret = -ENOMEM;
 828		goto out;
 829	}
 830
 831	nmh->nh_func = func;
 832	nmh->nh_func_data = data;
 833	nmh->nh_post_func = post_func;
 834	nmh->nh_msg_type = msg_type;
 835	nmh->nh_max_len = max_len;
 836	nmh->nh_key = key;
 837	/* the tree and list get this ref.. they're both removed in
 838	 * unregister when this ref is dropped */
 839	kref_init(&nmh->nh_kref);
 840	INIT_LIST_HEAD(&nmh->nh_unregister_item);
 841
 842	write_lock(&o2net_handler_lock);
 843	if (o2net_handler_tree_lookup(msg_type, key, &p, &parent))
 844		ret = -EEXIST;
 845	else {
 846	        rb_link_node(&nmh->nh_node, parent, p);
 847		rb_insert_color(&nmh->nh_node, &o2net_handler_tree);
 848		list_add_tail(&nmh->nh_unregister_item, unreg_list);
 849
 850		mlog(ML_TCP, "registered handler func %p type %u key %08x\n",
 851		     func, msg_type, key);
 852		/* we've had some trouble with handlers seemingly vanishing. */
 853		mlog_bug_on_msg(o2net_handler_tree_lookup(msg_type, key, &p,
 854							  &parent) == NULL,
 855			        "couldn't find handler we *just* registered "
 856				"for type %u key %08x\n", msg_type, key);
 857	}
 858	write_unlock(&o2net_handler_lock);
 859
 860out:
 861	if (ret)
 862		kfree(nmh);
 863
 864	return ret;
 865}
 866EXPORT_SYMBOL_GPL(o2net_register_handler);
 867
 868void o2net_unregister_handler_list(struct list_head *list)
 869{
 870	struct o2net_msg_handler *nmh, *n;
 871
 872	write_lock(&o2net_handler_lock);
 873	list_for_each_entry_safe(nmh, n, list, nh_unregister_item) {
 874		mlog(ML_TCP, "unregistering handler func %p type %u key %08x\n",
 875		     nmh->nh_func, nmh->nh_msg_type, nmh->nh_key);
 876		rb_erase(&nmh->nh_node, &o2net_handler_tree);
 877		list_del_init(&nmh->nh_unregister_item);
 878		kref_put(&nmh->nh_kref, o2net_handler_kref_release);
 879	}
 880	write_unlock(&o2net_handler_lock);
 881}
 882EXPORT_SYMBOL_GPL(o2net_unregister_handler_list);
 883
 884static struct o2net_msg_handler *o2net_handler_get(u32 msg_type, u32 key)
 885{
 886	struct o2net_msg_handler *nmh;
 887
 888	read_lock(&o2net_handler_lock);
 889	nmh = o2net_handler_tree_lookup(msg_type, key, NULL, NULL);
 890	if (nmh)
 891		kref_get(&nmh->nh_kref);
 892	read_unlock(&o2net_handler_lock);
 893
 894	return nmh;
 895}
 896
 897/* ------------------------------------------------------------ */
 898
 899static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
 900{
 901	struct kvec vec = { .iov_len = len, .iov_base = data, };
 902	struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
 903	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1, len);
 904	return sock_recvmsg(sock, &msg, MSG_DONTWAIT);
 905}
 906
 907static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
 908			      size_t veclen, size_t total)
 909{
 910	int ret;
 911	struct msghdr msg = {.msg_flags = 0,};
 912
 913	if (sock == NULL) {
 914		ret = -EINVAL;
 915		goto out;
 916	}
 917
 918	ret = kernel_sendmsg(sock, &msg, vec, veclen, total);
 919	if (likely(ret == total))
 920		return 0;
 921	mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret, total);
 922	if (ret >= 0)
 923		ret = -EPIPE; /* should be smarter, I bet */
 924out:
 925	mlog(0, "returning error: %d\n", ret);
 926	return ret;
 927}
 928
 929static void o2net_sendpage(struct o2net_sock_container *sc,
 930			   void *kmalloced_virt,
 931			   size_t size)
 932{
 933	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 
 
 934	ssize_t ret;
 935
 
 
 
 936	while (1) {
 
 937		mutex_lock(&sc->sc_send_lock);
 938		ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
 939						 virt_to_page(kmalloced_virt),
 940						 offset_in_page(kmalloced_virt),
 941						 size, MSG_DONTWAIT);
 942		mutex_unlock(&sc->sc_send_lock);
 
 943		if (ret == size)
 944			break;
 945		if (ret == (ssize_t)-EAGAIN) {
 946			mlog(0, "sendpage of size %zu to " SC_NODEF_FMT
 947			     " returned EAGAIN\n", size, SC_NODEF_ARGS(sc));
 948			cond_resched();
 949			continue;
 950		}
 951		mlog(ML_ERROR, "sendpage of size %zu to " SC_NODEF_FMT
 952		     " failed with %zd\n", size, SC_NODEF_ARGS(sc), ret);
 953		o2net_ensure_shutdown(nn, sc, 0);
 954		break;
 955	}
 956}
 957
 958static void o2net_init_msg(struct o2net_msg *msg, u16 data_len, u16 msg_type, u32 key)
 959{
 960	memset(msg, 0, sizeof(struct o2net_msg));
 961	msg->magic = cpu_to_be16(O2NET_MSG_MAGIC);
 962	msg->data_len = cpu_to_be16(data_len);
 963	msg->msg_type = cpu_to_be16(msg_type);
 964	msg->sys_status = cpu_to_be32(O2NET_ERR_NONE);
 965	msg->status = 0;
 966	msg->key = cpu_to_be32(key);
 967}
 968
 969static int o2net_tx_can_proceed(struct o2net_node *nn,
 970			        struct o2net_sock_container **sc_ret,
 971				int *error)
 972{
 973	int ret = 0;
 974
 975	spin_lock(&nn->nn_lock);
 976	if (nn->nn_persistent_error) {
 977		ret = 1;
 978		*sc_ret = NULL;
 979		*error = nn->nn_persistent_error;
 980	} else if (nn->nn_sc_valid) {
 981		kref_get(&nn->nn_sc->sc_kref);
 982
 983		ret = 1;
 984		*sc_ret = nn->nn_sc;
 985		*error = 0;
 986	}
 987	spin_unlock(&nn->nn_lock);
 988
 989	return ret;
 990}
 991
 992/* Get a map of all nodes to which this node is currently connected to */
 993void o2net_fill_node_map(unsigned long *map, unsigned int bits)
 994{
 995	struct o2net_sock_container *sc;
 996	int node, ret;
 997
 998	bitmap_zero(map, bits);
 999	for (node = 0; node < O2NM_MAX_NODES; ++node) {
1000		if (!o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret))
1001			continue;
1002		if (!ret) {
1003			set_bit(node, map);
1004			sc_put(sc);
1005		}
1006	}
1007}
1008EXPORT_SYMBOL_GPL(o2net_fill_node_map);
1009
1010int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
1011			   size_t caller_veclen, u8 target_node, int *status)
1012{
1013	int ret = 0;
1014	struct o2net_msg *msg = NULL;
1015	size_t veclen, caller_bytes = 0;
1016	struct kvec *vec = NULL;
1017	struct o2net_sock_container *sc = NULL;
1018	struct o2net_node *nn = o2net_nn_from_num(target_node);
1019	struct o2net_status_wait nsw = {
1020		.ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
1021	};
1022	struct o2net_send_tracking nst;
1023
1024	o2net_init_nst(&nst, msg_type, key, current, target_node);
1025
1026	if (o2net_wq == NULL) {
1027		mlog(0, "attempt to tx without o2netd running\n");
1028		ret = -ESRCH;
1029		goto out;
1030	}
1031
1032	if (caller_veclen == 0) {
1033		mlog(0, "bad kvec array length\n");
1034		ret = -EINVAL;
1035		goto out;
1036	}
1037
1038	caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
1039	if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
1040		mlog(0, "total payload len %zu too large\n", caller_bytes);
1041		ret = -EINVAL;
1042		goto out;
1043	}
1044
1045	if (target_node == o2nm_this_node()) {
1046		ret = -ELOOP;
1047		goto out;
1048	}
1049
1050	o2net_debug_add_nst(&nst);
1051
1052	o2net_set_nst_sock_time(&nst);
1053
1054	wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
1055	if (ret)
1056		goto out;
1057
1058	o2net_set_nst_sock_container(&nst, sc);
1059
1060	veclen = caller_veclen + 1;
1061	vec = kmalloc_array(veclen, sizeof(struct kvec), GFP_ATOMIC);
1062	if (vec == NULL) {
1063		mlog(0, "failed to %zu element kvec!\n", veclen);
1064		ret = -ENOMEM;
1065		goto out;
1066	}
1067
1068	msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
1069	if (!msg) {
1070		mlog(0, "failed to allocate a o2net_msg!\n");
1071		ret = -ENOMEM;
1072		goto out;
1073	}
1074
1075	o2net_init_msg(msg, caller_bytes, msg_type, key);
1076
1077	vec[0].iov_len = sizeof(struct o2net_msg);
1078	vec[0].iov_base = msg;
1079	memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
1080
1081	ret = o2net_prep_nsw(nn, &nsw);
1082	if (ret)
1083		goto out;
1084
1085	msg->msg_num = cpu_to_be32(nsw.ns_id);
1086	o2net_set_nst_msg_id(&nst, nsw.ns_id);
1087
1088	o2net_set_nst_send_time(&nst);
1089
1090	/* finally, convert the message header to network byte-order
1091	 * and send */
1092	mutex_lock(&sc->sc_send_lock);
1093	ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
1094				 sizeof(struct o2net_msg) + caller_bytes);
1095	mutex_unlock(&sc->sc_send_lock);
1096	msglog(msg, "sending returned %d\n", ret);
1097	if (ret < 0) {
1098		mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
1099		goto out;
1100	}
1101
1102	/* wait on other node's handler */
1103	o2net_set_nst_status_time(&nst);
1104	wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
1105
1106	o2net_update_send_stats(&nst, sc);
1107
1108	/* Note that we avoid overwriting the callers status return
1109	 * variable if a system error was reported on the other
1110	 * side. Callers beware. */
1111	ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
1112	if (status && !ret)
1113		*status = nsw.ns_status;
1114
1115	mlog(0, "woken, returning system status %d, user status %d\n",
1116	     ret, nsw.ns_status);
1117out:
1118	o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
1119	if (sc)
1120		sc_put(sc);
1121	kfree(vec);
1122	kfree(msg);
1123	o2net_complete_nsw(nn, &nsw, 0, 0, 0);
1124	return ret;
1125}
1126EXPORT_SYMBOL_GPL(o2net_send_message_vec);
1127
1128int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
1129		       u8 target_node, int *status)
1130{
1131	struct kvec vec = {
1132		.iov_base = data,
1133		.iov_len = len,
1134	};
1135	return o2net_send_message_vec(msg_type, key, &vec, 1,
1136				      target_node, status);
1137}
1138EXPORT_SYMBOL_GPL(o2net_send_message);
1139
1140static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
1141				   enum o2net_system_error syserr, int err)
1142{
1143	struct kvec vec = {
1144		.iov_base = hdr,
1145		.iov_len = sizeof(struct o2net_msg),
1146	};
1147
1148	BUG_ON(syserr >= O2NET_ERR_MAX);
1149
1150	/* leave other fields intact from the incoming message, msg_num
1151	 * in particular */
1152	hdr->sys_status = cpu_to_be32(syserr);
1153	hdr->status = cpu_to_be32(err);
1154	hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
1155	hdr->data_len = 0;
1156
1157	msglog(hdr, "about to send status magic %d\n", err);
1158	/* hdr has been in host byteorder this whole time */
1159	return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
1160}
1161
1162/* this returns -errno if the header was unknown or too large, etc.
1163 * after this is called the buffer us reused for the next message */
1164static int o2net_process_message(struct o2net_sock_container *sc,
1165				 struct o2net_msg *hdr)
1166{
1167	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1168	int ret = 0, handler_status;
1169	enum  o2net_system_error syserr;
1170	struct o2net_msg_handler *nmh = NULL;
1171	void *ret_data = NULL;
1172
1173	msglog(hdr, "processing message\n");
1174
1175	o2net_sc_postpone_idle(sc);
1176
1177	switch(be16_to_cpu(hdr->magic)) {
1178		case O2NET_MSG_STATUS_MAGIC:
1179			/* special type for returning message status */
1180			o2net_complete_nsw(nn, NULL,
1181					   be32_to_cpu(hdr->msg_num),
1182					   be32_to_cpu(hdr->sys_status),
1183					   be32_to_cpu(hdr->status));
1184			goto out;
1185		case O2NET_MSG_KEEP_REQ_MAGIC:
1186			o2net_sendpage(sc, o2net_keep_resp,
1187				       sizeof(*o2net_keep_resp));
1188			goto out;
1189		case O2NET_MSG_KEEP_RESP_MAGIC:
1190			goto out;
1191		case O2NET_MSG_MAGIC:
1192			break;
1193		default:
1194			msglog(hdr, "bad magic\n");
1195			ret = -EINVAL;
1196			goto out;
1197	}
1198
1199	/* find a handler for it */
1200	handler_status = 0;
1201	nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
1202				be32_to_cpu(hdr->key));
1203	if (!nmh) {
1204		mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
1205		     be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
1206		syserr = O2NET_ERR_NO_HNDLR;
1207		goto out_respond;
1208	}
1209
1210	syserr = O2NET_ERR_NONE;
1211
1212	if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
1213		syserr = O2NET_ERR_OVERFLOW;
1214
1215	if (syserr != O2NET_ERR_NONE)
1216		goto out_respond;
1217
1218	o2net_set_func_start_time(sc);
1219	sc->sc_msg_key = be32_to_cpu(hdr->key);
1220	sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
1221	handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
1222					     be16_to_cpu(hdr->data_len),
1223					nmh->nh_func_data, &ret_data);
1224	o2net_set_func_stop_time(sc);
1225
1226	o2net_update_recv_stats(sc);
1227
1228out_respond:
1229	/* this destroys the hdr, so don't use it after this */
1230	mutex_lock(&sc->sc_send_lock);
1231	ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
1232				      handler_status);
1233	mutex_unlock(&sc->sc_send_lock);
1234	hdr = NULL;
1235	mlog(0, "sending handler status %d, syserr %d returned %d\n",
1236	     handler_status, syserr, ret);
1237
1238	if (nmh) {
1239		BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
1240		if (nmh->nh_post_func)
1241			(nmh->nh_post_func)(handler_status, nmh->nh_func_data,
1242					    ret_data);
1243	}
1244
1245out:
1246	if (nmh)
1247		o2net_handler_put(nmh);
1248	return ret;
1249}
1250
1251static int o2net_check_handshake(struct o2net_sock_container *sc)
1252{
1253	struct o2net_handshake *hand = page_address(sc->sc_page);
1254	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1255
1256	if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
1257		printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
1258		       "protocol version %llu but %llu is required. "
1259		       "Disconnecting.\n", SC_NODEF_ARGS(sc),
1260		       (unsigned long long)be64_to_cpu(hand->protocol_version),
1261		       O2NET_PROTOCOL_VERSION);
1262
1263		/* don't bother reconnecting if its the wrong version. */
1264		o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1265		return -1;
1266	}
1267
1268	/*
1269	 * Ensure timeouts are consistent with other nodes, otherwise
1270	 * we can end up with one node thinking that the other must be down,
1271	 * but isn't. This can ultimately cause corruption.
1272	 */
1273	if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
1274				o2net_idle_timeout()) {
1275		printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
1276		       "idle timeout of %u ms, but we use %u ms locally. "
1277		       "Disconnecting.\n", SC_NODEF_ARGS(sc),
1278		       be32_to_cpu(hand->o2net_idle_timeout_ms),
1279		       o2net_idle_timeout());
1280		o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1281		return -1;
1282	}
1283
1284	if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
1285			o2net_keepalive_delay()) {
1286		printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
1287		       "delay of %u ms, but we use %u ms locally. "
1288		       "Disconnecting.\n", SC_NODEF_ARGS(sc),
1289		       be32_to_cpu(hand->o2net_keepalive_delay_ms),
1290		       o2net_keepalive_delay());
1291		o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1292		return -1;
1293	}
1294
1295	if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
1296			O2HB_MAX_WRITE_TIMEOUT_MS) {
1297		printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
1298		       "timeout of %u ms, but we use %u ms locally. "
1299		       "Disconnecting.\n", SC_NODEF_ARGS(sc),
1300		       be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
1301		       O2HB_MAX_WRITE_TIMEOUT_MS);
1302		o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1303		return -1;
1304	}
1305
1306	sc->sc_handshake_ok = 1;
1307
1308	spin_lock(&nn->nn_lock);
1309	/* set valid and queue the idle timers only if it hasn't been
1310	 * shut down already */
1311	if (nn->nn_sc == sc) {
1312		o2net_sc_reset_idle_timer(sc);
1313		atomic_set(&nn->nn_timeout, 0);
1314		o2net_set_nn_state(nn, sc, 1, 0);
1315	}
1316	spin_unlock(&nn->nn_lock);
1317
1318	/* shift everything up as though it wasn't there */
1319	sc->sc_page_off -= sizeof(struct o2net_handshake);
1320	if (sc->sc_page_off)
1321		memmove(hand, hand + 1, sc->sc_page_off);
1322
1323	return 0;
1324}
1325
1326/* this demuxes the queued rx bytes into header or payload bits and calls
1327 * handlers as each full message is read off the socket.  it returns -error,
1328 * == 0 eof, or > 0 for progress made.*/
1329static int o2net_advance_rx(struct o2net_sock_container *sc)
1330{
1331	struct o2net_msg *hdr;
1332	int ret = 0;
1333	void *data;
1334	size_t datalen;
1335
1336	sclog(sc, "receiving\n");
1337	o2net_set_advance_start_time(sc);
1338
1339	if (unlikely(sc->sc_handshake_ok == 0)) {
1340		if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
1341			data = page_address(sc->sc_page) + sc->sc_page_off;
1342			datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
1343			ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1344			if (ret > 0)
1345				sc->sc_page_off += ret;
1346		}
1347
1348		if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
1349			o2net_check_handshake(sc);
1350			if (unlikely(sc->sc_handshake_ok == 0))
1351				ret = -EPROTO;
1352		}
1353		goto out;
1354	}
1355
1356	/* do we need more header? */
1357	if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1358		data = page_address(sc->sc_page) + sc->sc_page_off;
1359		datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
1360		ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1361		if (ret > 0) {
1362			sc->sc_page_off += ret;
1363			/* only swab incoming here.. we can
1364			 * only get here once as we cross from
1365			 * being under to over */
1366			if (sc->sc_page_off == sizeof(struct o2net_msg)) {
1367				hdr = page_address(sc->sc_page);
1368				if (be16_to_cpu(hdr->data_len) >
1369				    O2NET_MAX_PAYLOAD_BYTES)
1370					ret = -EOVERFLOW;
1371			}
1372		}
1373		if (ret <= 0)
1374			goto out;
1375	}
1376
1377	if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1378		/* oof, still don't have a header */
1379		goto out;
1380	}
1381
1382	/* this was swabbed above when we first read it */
1383	hdr = page_address(sc->sc_page);
1384
1385	msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
1386
1387	/* do we need more payload? */
1388	if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
1389		/* need more payload */
1390		data = page_address(sc->sc_page) + sc->sc_page_off;
1391		datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
1392			  sc->sc_page_off;
1393		ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1394		if (ret > 0)
1395			sc->sc_page_off += ret;
1396		if (ret <= 0)
1397			goto out;
1398	}
1399
1400	if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
1401		/* we can only get here once, the first time we read
1402		 * the payload.. so set ret to progress if the handler
1403		 * works out. after calling this the message is toast */
1404		ret = o2net_process_message(sc, hdr);
1405		if (ret == 0)
1406			ret = 1;
1407		sc->sc_page_off = 0;
1408	}
1409
1410out:
1411	sclog(sc, "ret = %d\n", ret);
1412	o2net_set_advance_stop_time(sc);
1413	return ret;
1414}
1415
1416/* this work func is triggerd by data ready.  it reads until it can read no
1417 * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
1418 * our work the work struct will be marked and we'll be called again. */
1419static void o2net_rx_until_empty(struct work_struct *work)
1420{
1421	struct o2net_sock_container *sc =
1422		container_of(work, struct o2net_sock_container, sc_rx_work);
1423	int ret;
1424
1425	do {
1426		ret = o2net_advance_rx(sc);
1427	} while (ret > 0);
1428
1429	if (ret <= 0 && ret != -EAGAIN) {
1430		struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1431		sclog(sc, "saw error %d, closing\n", ret);
1432		/* not permanent so read failed handshake can retry */
1433		o2net_ensure_shutdown(nn, sc, 0);
1434	}
1435
1436	sc_put(sc);
1437}
1438
1439static void o2net_initialize_handshake(void)
1440{
1441	o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
1442		O2HB_MAX_WRITE_TIMEOUT_MS);
1443	o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
1444	o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
1445		o2net_keepalive_delay());
1446	o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
1447		o2net_reconnect_delay());
1448}
1449
1450/* ------------------------------------------------------------ */
1451
1452/* called when a connect completes and after a sock is accepted.  the
1453 * rx path will see the response and mark the sc valid */
1454static void o2net_sc_connect_completed(struct work_struct *work)
1455{
1456	struct o2net_sock_container *sc =
1457		container_of(work, struct o2net_sock_container,
1458			     sc_connect_work);
1459
1460	mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
1461              (unsigned long long)O2NET_PROTOCOL_VERSION,
1462	      (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
1463
1464	o2net_initialize_handshake();
1465	o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1466	sc_put(sc);
1467}
1468
1469/* this is called as a work_struct func. */
1470static void o2net_sc_send_keep_req(struct work_struct *work)
1471{
1472	struct o2net_sock_container *sc =
1473		container_of(work, struct o2net_sock_container,
1474			     sc_keepalive_work.work);
1475
1476	o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
1477	sc_put(sc);
1478}
1479
1480/* socket shutdown does a del_timer_sync against this as it tears down.
1481 * we can't start this timer until we've got to the point in sc buildup
1482 * where shutdown is going to be involved */
1483static void o2net_idle_timer(struct timer_list *t)
1484{
1485	struct o2net_sock_container *sc = from_timer(sc, t, sc_idle_timeout);
1486	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1487#ifdef CONFIG_DEBUG_FS
1488	unsigned long msecs = ktime_to_ms(ktime_get()) -
1489		ktime_to_ms(sc->sc_tv_timer);
1490#else
1491	unsigned long msecs = o2net_idle_timeout();
1492#endif
1493
1494	printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
1495	       "idle for %lu.%lu secs.\n",
1496	       SC_NODEF_ARGS(sc), msecs / 1000, msecs % 1000);
1497
1498	/* idle timerout happen, don't shutdown the connection, but
1499	 * make fence decision. Maybe the connection can recover before
1500	 * the decision is made.
1501	 */
1502	atomic_set(&nn->nn_timeout, 1);
1503	o2quo_conn_err(o2net_num_from_nn(nn));
1504	queue_delayed_work(o2net_wq, &nn->nn_still_up,
1505			msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
1506
1507	o2net_sc_reset_idle_timer(sc);
1508
1509}
1510
1511static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
1512{
1513	o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
1514	o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
1515		      msecs_to_jiffies(o2net_keepalive_delay()));
1516	o2net_set_sock_timer(sc);
1517	mod_timer(&sc->sc_idle_timeout,
1518	       jiffies + msecs_to_jiffies(o2net_idle_timeout()));
1519}
1520
1521static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
1522{
1523	struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1524
1525	/* clear fence decision since the connection recover from timeout*/
1526	if (atomic_read(&nn->nn_timeout)) {
1527		o2quo_conn_up(o2net_num_from_nn(nn));
1528		cancel_delayed_work(&nn->nn_still_up);
1529		atomic_set(&nn->nn_timeout, 0);
1530	}
1531
1532	/* Only push out an existing timer */
1533	if (timer_pending(&sc->sc_idle_timeout))
1534		o2net_sc_reset_idle_timer(sc);
1535}
1536
1537/* this work func is kicked whenever a path sets the nn state which doesn't
1538 * have valid set.  This includes seeing hb come up, losing a connection,
1539 * having a connect attempt fail, etc. This centralizes the logic which decides
1540 * if a connect attempt should be made or if we should give up and all future
1541 * transmit attempts should fail */
1542static void o2net_start_connect(struct work_struct *work)
1543{
1544	struct o2net_node *nn =
1545		container_of(work, struct o2net_node, nn_connect_work.work);
1546	struct o2net_sock_container *sc = NULL;
1547	struct o2nm_node *node = NULL, *mynode = NULL;
1548	struct socket *sock = NULL;
1549	struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
1550	int ret = 0, stop;
1551	unsigned int timeout;
1552	unsigned int nofs_flag;
1553
1554	/*
1555	 * sock_create allocates the sock with GFP_KERNEL. We must
1556	 * prevent the filesystem from being reentered by memory reclaim.
1557	 */
1558	nofs_flag = memalloc_nofs_save();
1559	/* if we're greater we initiate tx, otherwise we accept */
1560	if (o2nm_this_node() <= o2net_num_from_nn(nn))
1561		goto out;
1562
1563	/* watch for racing with tearing a node down */
1564	node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
1565	if (node == NULL)
1566		goto out;
1567
1568	mynode = o2nm_get_node_by_num(o2nm_this_node());
1569	if (mynode == NULL)
1570		goto out;
1571
1572	spin_lock(&nn->nn_lock);
1573	/*
1574	 * see if we already have one pending or have given up.
1575	 * For nn_timeout, it is set when we close the connection
1576	 * because of the idle time out. So it means that we have
1577	 * at least connected to that node successfully once,
1578	 * now try to connect to it again.
1579	 */
1580	timeout = atomic_read(&nn->nn_timeout);
1581	stop = (nn->nn_sc ||
1582		(nn->nn_persistent_error &&
1583		(nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
1584	spin_unlock(&nn->nn_lock);
1585	if (stop)
1586		goto out;
1587
1588	nn->nn_last_connect_attempt = jiffies;
1589
1590	sc = sc_alloc(node);
1591	if (sc == NULL) {
1592		mlog(0, "couldn't allocate sc\n");
1593		ret = -ENOMEM;
1594		goto out;
1595	}
1596
1597	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1598	if (ret < 0) {
1599		mlog(0, "can't create socket: %d\n", ret);
1600		goto out;
1601	}
1602	sc->sc_sock = sock; /* freed by sc_kref_release */
1603
1604	sock->sk->sk_allocation = GFP_ATOMIC;
1605	sock->sk->sk_use_task_frag = false;
1606
1607	myaddr.sin_family = AF_INET;
1608	myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
1609	myaddr.sin_port = htons(0); /* any port */
1610
1611	ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
1612			      sizeof(myaddr));
1613	if (ret) {
1614		mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
1615		     ret, &mynode->nd_ipv4_address);
1616		goto out;
1617	}
1618
1619	tcp_sock_set_nodelay(sc->sc_sock->sk);
1620	tcp_sock_set_user_timeout(sock->sk, O2NET_TCP_USER_TIMEOUT);
1621
1622	o2net_register_callbacks(sc->sc_sock->sk, sc);
1623
1624	spin_lock(&nn->nn_lock);
1625	/* handshake completion will set nn->nn_sc_valid */
1626	o2net_set_nn_state(nn, sc, 0, 0);
1627	spin_unlock(&nn->nn_lock);
1628
1629	remoteaddr.sin_family = AF_INET;
1630	remoteaddr.sin_addr.s_addr = node->nd_ipv4_address;
1631	remoteaddr.sin_port = node->nd_ipv4_port;
1632
1633	ret = sc->sc_sock->ops->connect(sc->sc_sock,
1634					(struct sockaddr *)&remoteaddr,
1635					sizeof(remoteaddr),
1636					O_NONBLOCK);
1637	if (ret == -EINPROGRESS)
1638		ret = 0;
1639
1640out:
1641	if (ret && sc) {
1642		printk(KERN_NOTICE "o2net: Connect attempt to " SC_NODEF_FMT
1643		       " failed with errno %d\n", SC_NODEF_ARGS(sc), ret);
1644		/* 0 err so that another will be queued and attempted
1645		 * from set_nn_state */
1646		o2net_ensure_shutdown(nn, sc, 0);
1647	}
1648	if (sc)
1649		sc_put(sc);
1650	if (node)
1651		o2nm_node_put(node);
1652	if (mynode)
1653		o2nm_node_put(mynode);
1654
1655	memalloc_nofs_restore(nofs_flag);
1656	return;
1657}
1658
1659static void o2net_connect_expired(struct work_struct *work)
1660{
1661	struct o2net_node *nn =
1662		container_of(work, struct o2net_node, nn_connect_expired.work);
1663
1664	spin_lock(&nn->nn_lock);
1665	if (!nn->nn_sc_valid) {
1666		printk(KERN_NOTICE "o2net: No connection established with "
1667		       "node %u after %u.%u seconds, check network and"
1668		       " cluster configuration.\n",
1669		     o2net_num_from_nn(nn),
1670		     o2net_idle_timeout() / 1000,
1671		     o2net_idle_timeout() % 1000);
1672
1673		o2net_set_nn_state(nn, NULL, 0, 0);
1674	}
1675	spin_unlock(&nn->nn_lock);
1676}
1677
1678static void o2net_still_up(struct work_struct *work)
1679{
1680	struct o2net_node *nn =
1681		container_of(work, struct o2net_node, nn_still_up.work);
1682
1683	o2quo_hb_still_up(o2net_num_from_nn(nn));
1684}
1685
1686/* ------------------------------------------------------------ */
1687
1688void o2net_disconnect_node(struct o2nm_node *node)
1689{
1690	struct o2net_node *nn = o2net_nn_from_num(node->nd_num);
1691
1692	/* don't reconnect until it's heartbeating again */
1693	spin_lock(&nn->nn_lock);
1694	atomic_set(&nn->nn_timeout, 0);
1695	o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
1696	spin_unlock(&nn->nn_lock);
1697
1698	if (o2net_wq) {
1699		cancel_delayed_work(&nn->nn_connect_expired);
1700		cancel_delayed_work(&nn->nn_connect_work);
1701		cancel_delayed_work(&nn->nn_still_up);
1702		flush_workqueue(o2net_wq);
1703	}
1704}
1705
1706static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
1707				  void *data)
1708{
1709	o2quo_hb_down(node_num);
1710
1711	if (!node)
1712		return;
1713
1714	if (node_num != o2nm_this_node())
1715		o2net_disconnect_node(node);
1716
1717	BUG_ON(atomic_read(&o2net_connected_peers) < 0);
1718}
1719
1720static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
1721				void *data)
1722{
1723	struct o2net_node *nn = o2net_nn_from_num(node_num);
1724
1725	o2quo_hb_up(node_num);
1726
1727	BUG_ON(!node);
1728
1729	/* ensure an immediate connect attempt */
1730	nn->nn_last_connect_attempt = jiffies -
1731		(msecs_to_jiffies(o2net_reconnect_delay()) + 1);
1732
1733	if (node_num != o2nm_this_node()) {
1734		/* believe it or not, accept and node heartbeating testing
1735		 * can succeed for this node before we got here.. so
1736		 * only use set_nn_state to clear the persistent error
1737		 * if that hasn't already happened */
1738		spin_lock(&nn->nn_lock);
1739		atomic_set(&nn->nn_timeout, 0);
1740		if (nn->nn_persistent_error)
1741			o2net_set_nn_state(nn, NULL, 0, 0);
1742		spin_unlock(&nn->nn_lock);
1743	}
1744}
1745
1746void o2net_unregister_hb_callbacks(void)
1747{
1748	o2hb_unregister_callback(NULL, &o2net_hb_up);
1749	o2hb_unregister_callback(NULL, &o2net_hb_down);
1750}
1751
1752int o2net_register_hb_callbacks(void)
1753{
1754	int ret;
1755
1756	o2hb_setup_callback(&o2net_hb_down, O2HB_NODE_DOWN_CB,
1757			    o2net_hb_node_down_cb, NULL, O2NET_HB_PRI);
1758	o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
1759			    o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
1760
1761	ret = o2hb_register_callback(NULL, &o2net_hb_up);
1762	if (ret == 0)
1763		ret = o2hb_register_callback(NULL, &o2net_hb_down);
1764
1765	if (ret)
1766		o2net_unregister_hb_callbacks();
1767
1768	return ret;
1769}
1770
1771/* ------------------------------------------------------------ */
1772
1773static int o2net_accept_one(struct socket *sock, int *more)
1774{
1775	int ret;
1776	struct sockaddr_in sin;
1777	struct socket *new_sock = NULL;
1778	struct o2nm_node *node = NULL;
1779	struct o2nm_node *local_node = NULL;
1780	struct o2net_sock_container *sc = NULL;
1781	struct o2net_node *nn;
1782	unsigned int nofs_flag;
1783
1784	/*
1785	 * sock_create_lite allocates the sock with GFP_KERNEL. We must
1786	 * prevent the filesystem from being reentered by memory reclaim.
1787	 */
1788	nofs_flag = memalloc_nofs_save();
1789
1790	BUG_ON(sock == NULL);
1791	*more = 0;
1792	ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
1793			       sock->sk->sk_protocol, &new_sock);
1794	if (ret)
1795		goto out;
1796
1797	new_sock->type = sock->type;
1798	new_sock->ops = sock->ops;
1799	ret = sock->ops->accept(sock, new_sock, O_NONBLOCK, false);
1800	if (ret < 0)
1801		goto out;
1802
1803	*more = 1;
1804	new_sock->sk->sk_allocation = GFP_ATOMIC;
1805
1806	tcp_sock_set_nodelay(new_sock->sk);
1807	tcp_sock_set_user_timeout(new_sock->sk, O2NET_TCP_USER_TIMEOUT);
1808
1809	ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin, 1);
1810	if (ret < 0)
1811		goto out;
1812
1813	node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
1814	if (node == NULL) {
1815		printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
1816		       "node at %pI4:%d\n", &sin.sin_addr.s_addr,
1817		       ntohs(sin.sin_port));
1818		ret = -EINVAL;
1819		goto out;
1820	}
1821
1822	if (o2nm_this_node() >= node->nd_num) {
1823		local_node = o2nm_get_node_by_num(o2nm_this_node());
1824		if (local_node)
1825			printk(KERN_NOTICE "o2net: Unexpected connect attempt "
1826					"seen at node '%s' (%u, %pI4:%d) from "
1827					"node '%s' (%u, %pI4:%d)\n",
1828					local_node->nd_name, local_node->nd_num,
1829					&(local_node->nd_ipv4_address),
1830					ntohs(local_node->nd_ipv4_port),
1831					node->nd_name,
1832					node->nd_num, &sin.sin_addr.s_addr,
1833					ntohs(sin.sin_port));
1834		ret = -EINVAL;
1835		goto out;
1836	}
1837
1838	/* this happens all the time when the other node sees our heartbeat
1839	 * and tries to connect before we see their heartbeat */
1840	if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
1841		mlog(ML_CONN, "attempt to connect from node '%s' at "
1842		     "%pI4:%d but it isn't heartbeating\n",
1843		     node->nd_name, &sin.sin_addr.s_addr,
1844		     ntohs(sin.sin_port));
1845		ret = -EINVAL;
1846		goto out;
1847	}
1848
1849	nn = o2net_nn_from_num(node->nd_num);
1850
1851	spin_lock(&nn->nn_lock);
1852	if (nn->nn_sc)
1853		ret = -EBUSY;
1854	else
1855		ret = 0;
1856	spin_unlock(&nn->nn_lock);
1857	if (ret) {
1858		printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
1859		       "at %pI4:%d but it already has an open connection\n",
1860		       node->nd_name, &sin.sin_addr.s_addr,
1861		       ntohs(sin.sin_port));
1862		goto out;
1863	}
1864
1865	sc = sc_alloc(node);
1866	if (sc == NULL) {
1867		ret = -ENOMEM;
1868		goto out;
1869	}
1870
1871	sc->sc_sock = new_sock;
1872	new_sock = NULL;
1873
1874	spin_lock(&nn->nn_lock);
1875	atomic_set(&nn->nn_timeout, 0);
1876	o2net_set_nn_state(nn, sc, 0, 0);
1877	spin_unlock(&nn->nn_lock);
1878
1879	o2net_register_callbacks(sc->sc_sock->sk, sc);
1880	o2net_sc_queue_work(sc, &sc->sc_rx_work);
1881
1882	o2net_initialize_handshake();
1883	o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1884
1885out:
1886	if (new_sock)
1887		sock_release(new_sock);
1888	if (node)
1889		o2nm_node_put(node);
1890	if (local_node)
1891		o2nm_node_put(local_node);
1892	if (sc)
1893		sc_put(sc);
1894
1895	memalloc_nofs_restore(nofs_flag);
1896	return ret;
1897}
1898
1899/*
1900 * This function is invoked in response to one or more
1901 * pending accepts at softIRQ level. We must drain the
1902 * entire que before returning.
1903 */
1904
1905static void o2net_accept_many(struct work_struct *work)
1906{
1907	struct socket *sock = o2net_listen_sock;
1908	int	more;
1909
1910	/*
1911	 * It is critical to note that due to interrupt moderation
1912	 * at the network driver level, we can't assume to get a
1913	 * softIRQ for every single conn since tcp SYN packets
1914	 * can arrive back-to-back, and therefore many pending
1915	 * accepts may result in just 1 softIRQ. If we terminate
1916	 * the o2net_accept_one() loop upon seeing an err, what happens
1917	 * to the rest of the conns in the queue? If no new SYN
1918	 * arrives for hours, no softIRQ  will be delivered,
1919	 * and the connections will just sit in the queue.
1920	 */
1921
1922	for (;;) {
1923		o2net_accept_one(sock, &more);
1924		if (!more)
1925			break;
1926		cond_resched();
1927	}
1928}
1929
1930static void o2net_listen_data_ready(struct sock *sk)
1931{
1932	void (*ready)(struct sock *sk);
1933
 
 
1934	read_lock_bh(&sk->sk_callback_lock);
1935	ready = sk->sk_user_data;
1936	if (ready == NULL) { /* check for teardown race */
1937		ready = sk->sk_data_ready;
1938		goto out;
1939	}
1940
1941	/* This callback may called twice when a new connection
1942	 * is  being established as a child socket inherits everything
1943	 * from a parent LISTEN socket, including the data_ready cb of
1944	 * the parent. This leads to a hazard. In o2net_accept_one()
1945	 * we are still initializing the child socket but have not
1946	 * changed the inherited data_ready callback yet when
1947	 * data starts arriving.
1948	 * We avoid this hazard by checking the state.
1949	 * For the listening socket,  the state will be TCP_LISTEN; for the new
1950	 * socket, will be  TCP_ESTABLISHED. Also, in this case,
1951	 * sk->sk_user_data is not a valid function pointer.
1952	 */
1953
1954	if (sk->sk_state == TCP_LISTEN) {
1955		queue_work(o2net_wq, &o2net_listen_work);
1956	} else {
1957		ready = NULL;
1958	}
1959
1960out:
1961	read_unlock_bh(&sk->sk_callback_lock);
1962	if (ready != NULL)
1963		ready(sk);
1964}
1965
1966static int o2net_open_listening_sock(__be32 addr, __be16 port)
1967{
1968	struct socket *sock = NULL;
1969	int ret;
1970	struct sockaddr_in sin = {
1971		.sin_family = PF_INET,
1972		.sin_addr = { .s_addr = addr },
1973		.sin_port = port,
1974	};
1975
1976	ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1977	if (ret < 0) {
1978		printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
1979		goto out;
1980	}
1981
1982	sock->sk->sk_allocation = GFP_ATOMIC;
1983
1984	write_lock_bh(&sock->sk->sk_callback_lock);
1985	sock->sk->sk_user_data = sock->sk->sk_data_ready;
1986	sock->sk->sk_data_ready = o2net_listen_data_ready;
1987	write_unlock_bh(&sock->sk->sk_callback_lock);
1988
1989	o2net_listen_sock = sock;
1990	INIT_WORK(&o2net_listen_work, o2net_accept_many);
1991
1992	sock->sk->sk_reuse = SK_CAN_REUSE;
1993	ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
1994	if (ret < 0) {
1995		printk(KERN_ERR "o2net: Error %d while binding socket at "
1996		       "%pI4:%u\n", ret, &addr, ntohs(port)); 
1997		goto out;
1998	}
1999
2000	ret = sock->ops->listen(sock, 64);
2001	if (ret < 0)
2002		printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
2003		       ret, &addr, ntohs(port));
2004
2005out:
2006	if (ret) {
2007		o2net_listen_sock = NULL;
2008		if (sock)
2009			sock_release(sock);
2010	}
2011	return ret;
2012}
2013
2014/*
2015 * called from node manager when we should bring up our network listening
2016 * socket.  node manager handles all the serialization to only call this
2017 * once and to match it with o2net_stop_listening().  note,
2018 * o2nm_this_node() doesn't work yet as we're being called while it
2019 * is being set up.
2020 */
2021int o2net_start_listening(struct o2nm_node *node)
2022{
2023	int ret = 0;
2024
2025	BUG_ON(o2net_wq != NULL);
2026	BUG_ON(o2net_listen_sock != NULL);
2027
2028	mlog(ML_KTHREAD, "starting o2net thread...\n");
2029	o2net_wq = alloc_ordered_workqueue("o2net", WQ_MEM_RECLAIM);
2030	if (o2net_wq == NULL) {
2031		mlog(ML_ERROR, "unable to launch o2net thread\n");
2032		return -ENOMEM; /* ? */
2033	}
2034
2035	ret = o2net_open_listening_sock(node->nd_ipv4_address,
2036					node->nd_ipv4_port);
2037	if (ret) {
2038		destroy_workqueue(o2net_wq);
2039		o2net_wq = NULL;
2040	} else
2041		o2quo_conn_up(node->nd_num);
2042
2043	return ret;
2044}
2045
2046/* again, o2nm_this_node() doesn't work here as we're involved in
2047 * tearing it down */
2048void o2net_stop_listening(struct o2nm_node *node)
2049{
2050	struct socket *sock = o2net_listen_sock;
2051	size_t i;
2052
2053	BUG_ON(o2net_wq == NULL);
2054	BUG_ON(o2net_listen_sock == NULL);
2055
2056	/* stop the listening socket from generating work */
2057	write_lock_bh(&sock->sk->sk_callback_lock);
2058	sock->sk->sk_data_ready = sock->sk->sk_user_data;
2059	sock->sk->sk_user_data = NULL;
2060	write_unlock_bh(&sock->sk->sk_callback_lock);
2061
2062	for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2063		struct o2nm_node *node = o2nm_get_node_by_num(i);
2064		if (node) {
2065			o2net_disconnect_node(node);
2066			o2nm_node_put(node);
2067		}
2068	}
2069
2070	/* finish all work and tear down the work queue */
2071	mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
2072	destroy_workqueue(o2net_wq);
2073	o2net_wq = NULL;
2074
2075	sock_release(o2net_listen_sock);
2076	o2net_listen_sock = NULL;
2077
2078	o2quo_conn_err(node->nd_num);
2079}
2080
2081/* ------------------------------------------------------------ */
2082
2083int o2net_init(void)
2084{
 
 
2085	unsigned long i;
2086
2087	o2quo_init();
2088
2089	o2net_debugfs_init();
2090
2091	o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
2092	o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2093	o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2094	if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp)
2095		goto out;
2096
 
 
 
 
 
 
 
2097	o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
2098	o2net_hand->connector_id = cpu_to_be64(1);
2099
2100	o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
2101	o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
2102
2103	for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2104		struct o2net_node *nn = o2net_nn_from_num(i);
2105
2106		atomic_set(&nn->nn_timeout, 0);
2107		spin_lock_init(&nn->nn_lock);
2108		INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
2109		INIT_DELAYED_WORK(&nn->nn_connect_expired,
2110				  o2net_connect_expired);
2111		INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
2112		/* until we see hb from a node we'll return einval */
2113		nn->nn_persistent_error = -ENOTCONN;
2114		init_waitqueue_head(&nn->nn_sc_wq);
2115		idr_init(&nn->nn_status_idr);
2116		INIT_LIST_HEAD(&nn->nn_status_list);
2117	}
2118
2119	return 0;
2120
2121out:
2122	kfree(o2net_hand);
2123	kfree(o2net_keep_req);
2124	kfree(o2net_keep_resp);
2125	o2net_debugfs_exit();
2126	o2quo_exit();
2127	return -ENOMEM;
2128}
2129
2130void o2net_exit(void)
2131{
2132	o2quo_exit();
2133	kfree(o2net_hand);
2134	kfree(o2net_keep_req);
2135	kfree(o2net_keep_resp);
2136	o2net_debugfs_exit();
 
2137}