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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/cluster/tcp.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /* -*- mode: c; c-basic-offset: 8; -*-
  3  *
  4  * vim: noexpandtab sw=8 ts=8 sts=0:
  5  *
  6  * Copyright (C) 2004 Oracle.  All rights reserved.
  7  *
  8  * ----
  9  *
 10  * Callers for this were originally written against a very simple synchronus
 11  * API.  This implementation reflects those simple callers.  Some day I'm sure
 12  * we'll need to move to a more robust posting/callback mechanism.
 13  *
 14  * Transmit calls pass in kernel virtual addresses and block copying this into
 15  * the socket's tx buffers via a usual blocking sendmsg.  They'll block waiting
 16  * for a failed socket to timeout.  TX callers can also pass in a poniter to an
 17  * 'int' which gets filled with an errno off the wire in response to the
 18  * message they send.
 19  *
 20  * Handlers for unsolicited messages are registered.  Each socket has a page
 21  * that incoming data is copied into.  First the header, then the data.
 22  * Handlers are called from only one thread with a reference to this per-socket
 23  * page.  This page is destroyed after the handler call, so it can't be
 24  * referenced beyond the call.  Handlers may block but are discouraged from
 25  * doing so.
 26  *
 27  * Any framing errors (bad magic, large payload lengths) close a connection.
 28  *
 29  * Our sock_container holds the state we associate with a socket.  It's current
 30  * framing state is held there as well as the refcounting we do around when it
 31  * is safe to tear down the socket.  The socket is only finally torn down from
 32  * the container when the container loses all of its references -- so as long
 33  * as you hold a ref on the container you can trust that the socket is valid
 34  * for use with kernel socket APIs.
 35  *
 36  * Connections are initiated between a pair of nodes when the node with the
 37  * higher node number gets a heartbeat callback which indicates that the lower
 38  * numbered node has started heartbeating.  The lower numbered node is passive
 39  * and only accepts the connection if the higher numbered node is heartbeating.
 40  */
 41 
 42 #include <linux/kernel.h>
 43 #include <linux/sched/mm.h>
 44 #include <linux/jiffies.h>
 45 #include <linux/slab.h>
 46 #include <linux/idr.h>
 47 #include <linux/kref.h>
 48 #include <linux/net.h>
 49 #include <linux/export.h>
 50 #include <net/tcp.h>
 51 
 52 #include <linux/uaccess.h>
 53 
 54 #include "heartbeat.h"
 55 #include "tcp.h"
 56 #include "nodemanager.h"
 57 #define MLOG_MASK_PREFIX ML_TCP
 58 #include "masklog.h"
 59 #include "quorum.h"
 60 
 61 #include "tcp_internal.h"
 62 
 63 #define SC_NODEF_FMT "node %s (num %u) at %pI4:%u"
 64 #define SC_NODEF_ARGS(sc) sc->sc_node->nd_name, sc->sc_node->nd_num,    \
 65                           &sc->sc_node->nd_ipv4_address,                \
 66                           ntohs(sc->sc_node->nd_ipv4_port)
 67 
 68 /*
 69  * In the following two log macros, the whitespace after the ',' just
 70  * before ##args is intentional. Otherwise, gcc 2.95 will eat the
 71  * previous token if args expands to nothing.
 72  */
 73 #define msglog(hdr, fmt, args...) do {                                  \
 74         typeof(hdr) __hdr = (hdr);                                      \
 75         mlog(ML_MSG, "[mag %u len %u typ %u stat %d sys_stat %d "       \
 76              "key %08x num %u] " fmt,                                   \
 77              be16_to_cpu(__hdr->magic), be16_to_cpu(__hdr->data_len),   \
 78              be16_to_cpu(__hdr->msg_type), be32_to_cpu(__hdr->status),  \
 79              be32_to_cpu(__hdr->sys_status), be32_to_cpu(__hdr->key),   \
 80              be32_to_cpu(__hdr->msg_num) ,  ##args);                    \
 81 } while (0)
 82 
 83 #define sclog(sc, fmt, args...) do {                                    \
 84         typeof(sc) __sc = (sc);                                         \
 85         mlog(ML_SOCKET, "[sc %p refs %d sock %p node %u page %p "       \
 86              "pg_off %zu] " fmt, __sc,                                  \
 87              kref_read(&__sc->sc_kref), __sc->sc_sock,  \
 88             __sc->sc_node->nd_num, __sc->sc_page, __sc->sc_page_off ,   \
 89             ##args);                                                    \
 90 } while (0)
 91 
 92 static DEFINE_RWLOCK(o2net_handler_lock);
 93 static struct rb_root o2net_handler_tree = RB_ROOT;
 94 
 95 static struct o2net_node o2net_nodes[O2NM_MAX_NODES];
 96 
 97 /* XXX someday we'll need better accounting */
 98 static struct socket *o2net_listen_sock;
 99 
100 /*
101  * listen work is only queued by the listening socket callbacks on the
102  * o2net_wq.  teardown detaches the callbacks before destroying the workqueue.
103  * quorum work is queued as sock containers are shutdown.. stop_listening
104  * tears down all the node's sock containers, preventing future shutdowns
105  * and queued quroum work, before canceling delayed quorum work and
106  * destroying the work queue.
107  */
108 static struct workqueue_struct *o2net_wq;
109 static struct work_struct o2net_listen_work;
110 
111 static struct o2hb_callback_func o2net_hb_up, o2net_hb_down;
112 #define O2NET_HB_PRI 0x1
113 
114 static struct o2net_handshake *o2net_hand;
115 static struct o2net_msg *o2net_keep_req, *o2net_keep_resp;
116 
117 static int o2net_sys_err_translations[O2NET_ERR_MAX] =
118                 {[O2NET_ERR_NONE]       = 0,
119                  [O2NET_ERR_NO_HNDLR]   = -ENOPROTOOPT,
120                  [O2NET_ERR_OVERFLOW]   = -EOVERFLOW,
121                  [O2NET_ERR_DIED]       = -EHOSTDOWN,};
122 
123 /* can't quite avoid *all* internal declarations :/ */
124 static void o2net_sc_connect_completed(struct work_struct *work);
125 static void o2net_rx_until_empty(struct work_struct *work);
126 static void o2net_shutdown_sc(struct work_struct *work);
127 static void o2net_listen_data_ready(struct sock *sk);
128 static void o2net_sc_send_keep_req(struct work_struct *work);
129 static void o2net_idle_timer(struct timer_list *t);
130 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc);
131 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc);
132 
133 #ifdef CONFIG_DEBUG_FS
134 static void o2net_init_nst(struct o2net_send_tracking *nst, u32 msgtype,
135                            u32 msgkey, struct task_struct *task, u8 node)
136 {
137         INIT_LIST_HEAD(&nst->st_net_debug_item);
138         nst->st_task = task;
139         nst->st_msg_type = msgtype;
140         nst->st_msg_key = msgkey;
141         nst->st_node = node;
142 }
143 
144 static inline void o2net_set_nst_sock_time(struct o2net_send_tracking *nst)
145 {
146         nst->st_sock_time = ktime_get();
147 }
148 
149 static inline void o2net_set_nst_send_time(struct o2net_send_tracking *nst)
150 {
151         nst->st_send_time = ktime_get();
152 }
153 
154 static inline void o2net_set_nst_status_time(struct o2net_send_tracking *nst)
155 {
156         nst->st_status_time = ktime_get();
157 }
158 
159 static inline void o2net_set_nst_sock_container(struct o2net_send_tracking *nst,
160                                                 struct o2net_sock_container *sc)
161 {
162         nst->st_sc = sc;
163 }
164 
165 static inline void o2net_set_nst_msg_id(struct o2net_send_tracking *nst,
166                                         u32 msg_id)
167 {
168         nst->st_id = msg_id;
169 }
170 
171 static inline void o2net_set_sock_timer(struct o2net_sock_container *sc)
172 {
173         sc->sc_tv_timer = ktime_get();
174 }
175 
176 static inline void o2net_set_data_ready_time(struct o2net_sock_container *sc)
177 {
178         sc->sc_tv_data_ready = ktime_get();
179 }
180 
181 static inline void o2net_set_advance_start_time(struct o2net_sock_container *sc)
182 {
183         sc->sc_tv_advance_start = ktime_get();
184 }
185 
186 static inline void o2net_set_advance_stop_time(struct o2net_sock_container *sc)
187 {
188         sc->sc_tv_advance_stop = ktime_get();
189 }
190 
191 static inline void o2net_set_func_start_time(struct o2net_sock_container *sc)
192 {
193         sc->sc_tv_func_start = ktime_get();
194 }
195 
196 static inline void o2net_set_func_stop_time(struct o2net_sock_container *sc)
197 {
198         sc->sc_tv_func_stop = ktime_get();
199 }
200 
201 #else  /* CONFIG_DEBUG_FS */
202 # define o2net_init_nst(a, b, c, d, e)
203 # define o2net_set_nst_sock_time(a)
204 # define o2net_set_nst_send_time(a)
205 # define o2net_set_nst_status_time(a)
206 # define o2net_set_nst_sock_container(a, b)
207 # define o2net_set_nst_msg_id(a, b)
208 # define o2net_set_sock_timer(a)
209 # define o2net_set_data_ready_time(a)
210 # define o2net_set_advance_start_time(a)
211 # define o2net_set_advance_stop_time(a)
212 # define o2net_set_func_start_time(a)
213 # define o2net_set_func_stop_time(a)
214 #endif /* CONFIG_DEBUG_FS */
215 
216 #ifdef CONFIG_OCFS2_FS_STATS
217 static ktime_t o2net_get_func_run_time(struct o2net_sock_container *sc)
218 {
219         return ktime_sub(sc->sc_tv_func_stop, sc->sc_tv_func_start);
220 }
221 
222 static void o2net_update_send_stats(struct o2net_send_tracking *nst,
223                                     struct o2net_sock_container *sc)
224 {
225         sc->sc_tv_status_total = ktime_add(sc->sc_tv_status_total,
226                                            ktime_sub(ktime_get(),
227                                                      nst->st_status_time));
228         sc->sc_tv_send_total = ktime_add(sc->sc_tv_send_total,
229                                          ktime_sub(nst->st_status_time,
230                                                    nst->st_send_time));
231         sc->sc_tv_acquiry_total = ktime_add(sc->sc_tv_acquiry_total,
232                                             ktime_sub(nst->st_send_time,
233                                                       nst->st_sock_time));
234         sc->sc_send_count++;
235 }
236 
237 static void o2net_update_recv_stats(struct o2net_sock_container *sc)
238 {
239         sc->sc_tv_process_total = ktime_add(sc->sc_tv_process_total,
240                                             o2net_get_func_run_time(sc));
241         sc->sc_recv_count++;
242 }
243 
244 #else
245 
246 # define o2net_update_send_stats(a, b)
247 
248 # define o2net_update_recv_stats(sc)
249 
250 #endif /* CONFIG_OCFS2_FS_STATS */
251 
252 static inline unsigned int o2net_reconnect_delay(void)
253 {
254         return o2nm_single_cluster->cl_reconnect_delay_ms;
255 }
256 
257 static inline unsigned int o2net_keepalive_delay(void)
258 {
259         return o2nm_single_cluster->cl_keepalive_delay_ms;
260 }
261 
262 static inline unsigned int o2net_idle_timeout(void)
263 {
264         return o2nm_single_cluster->cl_idle_timeout_ms;
265 }
266 
267 static inline int o2net_sys_err_to_errno(enum o2net_system_error err)
268 {
269         int trans;
270         BUG_ON(err >= O2NET_ERR_MAX);
271         trans = o2net_sys_err_translations[err];
272 
273         /* Just in case we mess up the translation table above */
274         BUG_ON(err != O2NET_ERR_NONE && trans == 0);
275         return trans;
276 }
277 
278 static struct o2net_node * o2net_nn_from_num(u8 node_num)
279 {
280         BUG_ON(node_num >= ARRAY_SIZE(o2net_nodes));
281         return &o2net_nodes[node_num];
282 }
283 
284 static u8 o2net_num_from_nn(struct o2net_node *nn)
285 {
286         BUG_ON(nn == NULL);
287         return nn - o2net_nodes;
288 }
289 
290 /* ------------------------------------------------------------ */
291 
292 static int o2net_prep_nsw(struct o2net_node *nn, struct o2net_status_wait *nsw)
293 {
294         int ret;
295 
296         spin_lock(&nn->nn_lock);
297         ret = idr_alloc(&nn->nn_status_idr, nsw, 0, 0, GFP_ATOMIC);
298         if (ret >= 0) {
299                 nsw->ns_id = ret;
300                 list_add_tail(&nsw->ns_node_item, &nn->nn_status_list);
301         }
302         spin_unlock(&nn->nn_lock);
303         if (ret < 0)
304                 return ret;
305 
306         init_waitqueue_head(&nsw->ns_wq);
307         nsw->ns_sys_status = O2NET_ERR_NONE;
308         nsw->ns_status = 0;
309         return 0;
310 }
311 
312 static void o2net_complete_nsw_locked(struct o2net_node *nn,
313                                       struct o2net_status_wait *nsw,
314                                       enum o2net_system_error sys_status,
315                                       s32 status)
316 {
317         assert_spin_locked(&nn->nn_lock);
318 
319         if (!list_empty(&nsw->ns_node_item)) {
320                 list_del_init(&nsw->ns_node_item);
321                 nsw->ns_sys_status = sys_status;
322                 nsw->ns_status = status;
323                 idr_remove(&nn->nn_status_idr, nsw->ns_id);
324                 wake_up(&nsw->ns_wq);
325         }
326 }
327 
328 static void o2net_complete_nsw(struct o2net_node *nn,
329                                struct o2net_status_wait *nsw,
330                                u64 id, enum o2net_system_error sys_status,
331                                s32 status)
332 {
333         spin_lock(&nn->nn_lock);
334         if (nsw == NULL) {
335                 if (id > INT_MAX)
336                         goto out;
337 
338                 nsw = idr_find(&nn->nn_status_idr, id);
339                 if (nsw == NULL)
340                         goto out;
341         }
342 
343         o2net_complete_nsw_locked(nn, nsw, sys_status, status);
344 
345 out:
346         spin_unlock(&nn->nn_lock);
347         return;
348 }
349 
350 static void o2net_complete_nodes_nsw(struct o2net_node *nn)
351 {
352         struct o2net_status_wait *nsw, *tmp;
353         unsigned int num_kills = 0;
354 
355         assert_spin_locked(&nn->nn_lock);
356 
357         list_for_each_entry_safe(nsw, tmp, &nn->nn_status_list, ns_node_item) {
358                 o2net_complete_nsw_locked(nn, nsw, O2NET_ERR_DIED, 0);
359                 num_kills++;
360         }
361 
362         mlog(0, "completed %d messages for node %u\n", num_kills,
363              o2net_num_from_nn(nn));
364 }
365 
366 static int o2net_nsw_completed(struct o2net_node *nn,
367                                struct o2net_status_wait *nsw)
368 {
369         int completed;
370         spin_lock(&nn->nn_lock);
371         completed = list_empty(&nsw->ns_node_item);
372         spin_unlock(&nn->nn_lock);
373         return completed;
374 }
375 
376 /* ------------------------------------------------------------ */
377 
378 static void sc_kref_release(struct kref *kref)
379 {
380         struct o2net_sock_container *sc = container_of(kref,
381                                         struct o2net_sock_container, sc_kref);
382         BUG_ON(timer_pending(&sc->sc_idle_timeout));
383 
384         sclog(sc, "releasing\n");
385 
386         if (sc->sc_sock) {
387                 sock_release(sc->sc_sock);
388                 sc->sc_sock = NULL;
389         }
390 
391         o2nm_undepend_item(&sc->sc_node->nd_item);
392         o2nm_node_put(sc->sc_node);
393         sc->sc_node = NULL;
394 
395         o2net_debug_del_sc(sc);
396 
397         if (sc->sc_page)
398                 __free_page(sc->sc_page);
399         kfree(sc);
400 }
401 
402 static void sc_put(struct o2net_sock_container *sc)
403 {
404         sclog(sc, "put\n");
405         kref_put(&sc->sc_kref, sc_kref_release);
406 }
407 static void sc_get(struct o2net_sock_container *sc)
408 {
409         sclog(sc, "get\n");
410         kref_get(&sc->sc_kref);
411 }
412 static struct o2net_sock_container *sc_alloc(struct o2nm_node *node)
413 {
414         struct o2net_sock_container *sc, *ret = NULL;
415         struct page *page = NULL;
416         int status = 0;
417 
418         page = alloc_page(GFP_NOFS);
419         sc = kzalloc(sizeof(*sc), GFP_NOFS);
420         if (sc == NULL || page == NULL)
421                 goto out;
422 
423         kref_init(&sc->sc_kref);
424         o2nm_node_get(node);
425         sc->sc_node = node;
426 
427         /* pin the node item of the remote node */
428         status = o2nm_depend_item(&node->nd_item);
429         if (status) {
430                 mlog_errno(status);
431                 o2nm_node_put(node);
432                 goto out;
433         }
434         INIT_WORK(&sc->sc_connect_work, o2net_sc_connect_completed);
435         INIT_WORK(&sc->sc_rx_work, o2net_rx_until_empty);
436         INIT_WORK(&sc->sc_shutdown_work, o2net_shutdown_sc);
437         INIT_DELAYED_WORK(&sc->sc_keepalive_work, o2net_sc_send_keep_req);
438 
439         timer_setup(&sc->sc_idle_timeout, o2net_idle_timer, 0);
440 
441         sclog(sc, "alloced\n");
442 
443         ret = sc;
444         sc->sc_page = page;
445         o2net_debug_add_sc(sc);
446         sc = NULL;
447         page = NULL;
448 
449 out:
450         if (page)
451                 __free_page(page);
452         kfree(sc);
453 
454         return ret;
455 }
456 
457 /* ------------------------------------------------------------ */
458 
459 static void o2net_sc_queue_work(struct o2net_sock_container *sc,
460                                 struct work_struct *work)
461 {
462         sc_get(sc);
463         if (!queue_work(o2net_wq, work))
464                 sc_put(sc);
465 }
466 static void o2net_sc_queue_delayed_work(struct o2net_sock_container *sc,
467                                         struct delayed_work *work,
468                                         int delay)
469 {
470         sc_get(sc);
471         if (!queue_delayed_work(o2net_wq, work, delay))
472                 sc_put(sc);
473 }
474 static void o2net_sc_cancel_delayed_work(struct o2net_sock_container *sc,
475                                          struct delayed_work *work)
476 {
477         if (cancel_delayed_work(work))
478                 sc_put(sc);
479 }
480 
481 static atomic_t o2net_connected_peers = ATOMIC_INIT(0);
482 
483 int o2net_num_connected_peers(void)
484 {
485         return atomic_read(&o2net_connected_peers);
486 }
487 
488 static void o2net_set_nn_state(struct o2net_node *nn,
489                                struct o2net_sock_container *sc,
490                                unsigned valid, int err)
491 {
492         int was_valid = nn->nn_sc_valid;
493         int was_err = nn->nn_persistent_error;
494         struct o2net_sock_container *old_sc = nn->nn_sc;
495 
496         assert_spin_locked(&nn->nn_lock);
497 
498         if (old_sc && !sc)
499                 atomic_dec(&o2net_connected_peers);
500         else if (!old_sc && sc)
501                 atomic_inc(&o2net_connected_peers);
502 
503         /* the node num comparison and single connect/accept path should stop
504          * an non-null sc from being overwritten with another */
505         BUG_ON(sc && nn->nn_sc && nn->nn_sc != sc);
506         mlog_bug_on_msg(err && valid, "err %d valid %u\n", err, valid);
507         mlog_bug_on_msg(valid && !sc, "valid %u sc %p\n", valid, sc);
508 
509         if (was_valid && !valid && err == 0)
510                 err = -ENOTCONN;
511 
512         mlog(ML_CONN, "node %u sc: %p -> %p, valid %u -> %u, err %d -> %d\n",
513              o2net_num_from_nn(nn), nn->nn_sc, sc, nn->nn_sc_valid, valid,
514              nn->nn_persistent_error, err);
515 
516         nn->nn_sc = sc;
517         nn->nn_sc_valid = valid ? 1 : 0;
518         nn->nn_persistent_error = err;
519 
520         /* mirrors o2net_tx_can_proceed() */
521         if (nn->nn_persistent_error || nn->nn_sc_valid)
522                 wake_up(&nn->nn_sc_wq);
523 
524         if (was_valid && !was_err && nn->nn_persistent_error) {
525                 o2quo_conn_err(o2net_num_from_nn(nn));
526                 queue_delayed_work(o2net_wq, &nn->nn_still_up,
527                                    msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
528         }
529 
530         if (was_valid && !valid) {
531                 if (old_sc)
532                         printk(KERN_NOTICE "o2net: No longer connected to "
533                                 SC_NODEF_FMT "\n", SC_NODEF_ARGS(old_sc));
534                 o2net_complete_nodes_nsw(nn);
535         }
536 
537         if (!was_valid && valid) {
538                 o2quo_conn_up(o2net_num_from_nn(nn));
539                 cancel_delayed_work(&nn->nn_connect_expired);
540                 printk(KERN_NOTICE "o2net: %s " SC_NODEF_FMT "\n",
541                        o2nm_this_node() > sc->sc_node->nd_num ?
542                        "Connected to" : "Accepted connection from",
543                        SC_NODEF_ARGS(sc));
544         }
545 
546         /* trigger the connecting worker func as long as we're not valid,
547          * it will back off if it shouldn't connect.  This can be called
548          * from node config teardown and so needs to be careful about
549          * the work queue actually being up. */
550         if (!valid && o2net_wq) {
551                 unsigned long delay;
552                 /* delay if we're within a RECONNECT_DELAY of the
553                  * last attempt */
554                 delay = (nn->nn_last_connect_attempt +
555                          msecs_to_jiffies(o2net_reconnect_delay()))
556                         - jiffies;
557                 if (delay > msecs_to_jiffies(o2net_reconnect_delay()))
558                         delay = 0;
559                 mlog(ML_CONN, "queueing conn attempt in %lu jiffies\n", delay);
560                 queue_delayed_work(o2net_wq, &nn->nn_connect_work, delay);
561 
562                 /*
563                  * Delay the expired work after idle timeout.
564                  *
565                  * We might have lots of failed connection attempts that run
566                  * through here but we only cancel the connect_expired work when
567                  * a connection attempt succeeds.  So only the first enqueue of
568                  * the connect_expired work will do anything.  The rest will see
569                  * that it's already queued and do nothing.
570                  */
571                 delay += msecs_to_jiffies(o2net_idle_timeout());
572                 queue_delayed_work(o2net_wq, &nn->nn_connect_expired, delay);
573         }
574 
575         /* keep track of the nn's sc ref for the caller */
576         if ((old_sc == NULL) && sc)
577                 sc_get(sc);
578         if (old_sc && (old_sc != sc)) {
579                 o2net_sc_queue_work(old_sc, &old_sc->sc_shutdown_work);
580                 sc_put(old_sc);
581         }
582 }
583 
584 /* see o2net_register_callbacks() */
585 static void o2net_data_ready(struct sock *sk)
586 {
587         void (*ready)(struct sock *sk);
588         struct o2net_sock_container *sc;
589 
590         read_lock_bh(&sk->sk_callback_lock);
591         sc = sk->sk_user_data;
592         if (sc) {
593                 sclog(sc, "data_ready hit\n");
594                 o2net_set_data_ready_time(sc);
595                 o2net_sc_queue_work(sc, &sc->sc_rx_work);
596                 ready = sc->sc_data_ready;
597         } else {
598                 ready = sk->sk_data_ready;
599         }
600         read_unlock_bh(&sk->sk_callback_lock);
601 
602         ready(sk);
603 }
604 
605 /* see o2net_register_callbacks() */
606 static void o2net_state_change(struct sock *sk)
607 {
608         void (*state_change)(struct sock *sk);
609         struct o2net_sock_container *sc;
610 
611         read_lock_bh(&sk->sk_callback_lock);
612         sc = sk->sk_user_data;
613         if (sc == NULL) {
614                 state_change = sk->sk_state_change;
615                 goto out;
616         }
617 
618         sclog(sc, "state_change to %d\n", sk->sk_state);
619 
620         state_change = sc->sc_state_change;
621 
622         switch(sk->sk_state) {
623         /* ignore connecting sockets as they make progress */
624         case TCP_SYN_SENT:
625         case TCP_SYN_RECV:
626                 break;
627         case TCP_ESTABLISHED:
628                 o2net_sc_queue_work(sc, &sc->sc_connect_work);
629                 break;
630         default:
631                 printk(KERN_INFO "o2net: Connection to " SC_NODEF_FMT
632                         " shutdown, state %d\n",
633                         SC_NODEF_ARGS(sc), sk->sk_state);
634                 o2net_sc_queue_work(sc, &sc->sc_shutdown_work);
635                 break;
636         }
637 out:
638         read_unlock_bh(&sk->sk_callback_lock);
639         state_change(sk);
640 }
641 
642 /*
643  * we register callbacks so we can queue work on events before calling
644  * the original callbacks.  our callbacks our careful to test user_data
645  * to discover when they've reaced with o2net_unregister_callbacks().
646  */
647 static void o2net_register_callbacks(struct sock *sk,
648                                      struct o2net_sock_container *sc)
649 {
650         write_lock_bh(&sk->sk_callback_lock);
651 
652         /* accepted sockets inherit the old listen socket data ready */
653         if (sk->sk_data_ready == o2net_listen_data_ready) {
654                 sk->sk_data_ready = sk->sk_user_data;
655                 sk->sk_user_data = NULL;
656         }
657 
658         BUG_ON(sk->sk_user_data != NULL);
659         sk->sk_user_data = sc;
660         sc_get(sc);
661 
662         sc->sc_data_ready = sk->sk_data_ready;
663         sc->sc_state_change = sk->sk_state_change;
664         sk->sk_data_ready = o2net_data_ready;
665         sk->sk_state_change = o2net_state_change;
666 
667         mutex_init(&sc->sc_send_lock);
668 
669         write_unlock_bh(&sk->sk_callback_lock);
670 }
671 
672 static int o2net_unregister_callbacks(struct sock *sk,
673                                    struct o2net_sock_container *sc)
674 {
675         int ret = 0;
676 
677         write_lock_bh(&sk->sk_callback_lock);
678         if (sk->sk_user_data == sc) {
679                 ret = 1;
680                 sk->sk_user_data = NULL;
681                 sk->sk_data_ready = sc->sc_data_ready;
682                 sk->sk_state_change = sc->sc_state_change;
683         }
684         write_unlock_bh(&sk->sk_callback_lock);
685 
686         return ret;
687 }
688 
689 /*
690  * this is a little helper that is called by callers who have seen a problem
691  * with an sc and want to detach it from the nn if someone already hasn't beat
692  * them to it.  if an error is given then the shutdown will be persistent
693  * and pending transmits will be canceled.
694  */
695 static void o2net_ensure_shutdown(struct o2net_node *nn,
696                                    struct o2net_sock_container *sc,
697                                    int err)
698 {
699         spin_lock(&nn->nn_lock);
700         if (nn->nn_sc == sc)
701                 o2net_set_nn_state(nn, NULL, 0, err);
702         spin_unlock(&nn->nn_lock);
703 }
704 
705 /*
706  * This work queue function performs the blocking parts of socket shutdown.  A
707  * few paths lead here.  set_nn_state will trigger this callback if it sees an
708  * sc detached from the nn.  state_change will also trigger this callback
709  * directly when it sees errors.  In that case we need to call set_nn_state
710  * ourselves as state_change couldn't get the nn_lock and call set_nn_state
711  * itself.
712  */
713 static void o2net_shutdown_sc(struct work_struct *work)
714 {
715         struct o2net_sock_container *sc =
716                 container_of(work, struct o2net_sock_container,
717                              sc_shutdown_work);
718         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
719 
720         sclog(sc, "shutting down\n");
721 
722         /* drop the callbacks ref and call shutdown only once */
723         if (o2net_unregister_callbacks(sc->sc_sock->sk, sc)) {
724                 /* we shouldn't flush as we're in the thread, the
725                  * races with pending sc work structs are harmless */
726                 del_timer_sync(&sc->sc_idle_timeout);
727                 o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
728                 sc_put(sc);
729                 kernel_sock_shutdown(sc->sc_sock, SHUT_RDWR);
730         }
731 
732         /* not fatal so failed connects before the other guy has our
733          * heartbeat can be retried */
734         o2net_ensure_shutdown(nn, sc, 0);
735         sc_put(sc);
736 }
737 
738 /* ------------------------------------------------------------ */
739 
740 static int o2net_handler_cmp(struct o2net_msg_handler *nmh, u32 msg_type,
741                              u32 key)
742 {
743         int ret = memcmp(&nmh->nh_key, &key, sizeof(key));
744 
745         if (ret == 0)
746                 ret = memcmp(&nmh->nh_msg_type, &msg_type, sizeof(msg_type));
747 
748         return ret;
749 }
750 
751 static struct o2net_msg_handler *
752 o2net_handler_tree_lookup(u32 msg_type, u32 key, struct rb_node ***ret_p,
753                           struct rb_node **ret_parent)
754 {
755         struct rb_node **p = &o2net_handler_tree.rb_node;
756         struct rb_node *parent = NULL;
757         struct o2net_msg_handler *nmh, *ret = NULL;
758         int cmp;
759 
760         while (*p) {
761                 parent = *p;
762                 nmh = rb_entry(parent, struct o2net_msg_handler, nh_node);
763                 cmp = o2net_handler_cmp(nmh, msg_type, key);
764 
765                 if (cmp < 0)
766                         p = &(*p)->rb_left;
767                 else if (cmp > 0)
768                         p = &(*p)->rb_right;
769                 else {
770                         ret = nmh;
771                         break;
772                 }
773         }
774 
775         if (ret_p != NULL)
776                 *ret_p = p;
777         if (ret_parent != NULL)
778                 *ret_parent = parent;
779 
780         return ret;
781 }
782 
783 static void o2net_handler_kref_release(struct kref *kref)
784 {
785         struct o2net_msg_handler *nmh;
786         nmh = container_of(kref, struct o2net_msg_handler, nh_kref);
787 
788         kfree(nmh);
789 }
790 
791 static void o2net_handler_put(struct o2net_msg_handler *nmh)
792 {
793         kref_put(&nmh->nh_kref, o2net_handler_kref_release);
794 }
795 
796 /* max_len is protection for the handler func.  incoming messages won't
797  * be given to the handler if their payload is longer than the max. */
798 int o2net_register_handler(u32 msg_type, u32 key, u32 max_len,
799                            o2net_msg_handler_func *func, void *data,
800                            o2net_post_msg_handler_func *post_func,
801                            struct list_head *unreg_list)
802 {
803         struct o2net_msg_handler *nmh = NULL;
804         struct rb_node **p, *parent;
805         int ret = 0;
806 
807         if (max_len > O2NET_MAX_PAYLOAD_BYTES) {
808                 mlog(0, "max_len for message handler out of range: %u\n",
809                         max_len);
810                 ret = -EINVAL;
811                 goto out;
812         }
813 
814         if (!msg_type) {
815                 mlog(0, "no message type provided: %u, %p\n", msg_type, func);
816                 ret = -EINVAL;
817                 goto out;
818 
819         }
820         if (!func) {
821                 mlog(0, "no message handler provided: %u, %p\n",
822                        msg_type, func);
823                 ret = -EINVAL;
824                 goto out;
825         }
826 
827         nmh = kzalloc(sizeof(struct o2net_msg_handler), GFP_NOFS);
828         if (nmh == NULL) {
829                 ret = -ENOMEM;
830                 goto out;
831         }
832 
833         nmh->nh_func = func;
834         nmh->nh_func_data = data;
835         nmh->nh_post_func = post_func;
836         nmh->nh_msg_type = msg_type;
837         nmh->nh_max_len = max_len;
838         nmh->nh_key = key;
839         /* the tree and list get this ref.. they're both removed in
840          * unregister when this ref is dropped */
841         kref_init(&nmh->nh_kref);
842         INIT_LIST_HEAD(&nmh->nh_unregister_item);
843 
844         write_lock(&o2net_handler_lock);
845         if (o2net_handler_tree_lookup(msg_type, key, &p, &parent))
846                 ret = -EEXIST;
847         else {
848                 rb_link_node(&nmh->nh_node, parent, p);
849                 rb_insert_color(&nmh->nh_node, &o2net_handler_tree);
850                 list_add_tail(&nmh->nh_unregister_item, unreg_list);
851 
852                 mlog(ML_TCP, "registered handler func %p type %u key %08x\n",
853                      func, msg_type, key);
854                 /* we've had some trouble with handlers seemingly vanishing. */
855                 mlog_bug_on_msg(o2net_handler_tree_lookup(msg_type, key, &p,
856                                                           &parent) == NULL,
857                                 "couldn't find handler we *just* registered "
858                                 "for type %u key %08x\n", msg_type, key);
859         }
860         write_unlock(&o2net_handler_lock);
861 
862 out:
863         if (ret)
864                 kfree(nmh);
865 
866         return ret;
867 }
868 EXPORT_SYMBOL_GPL(o2net_register_handler);
869 
870 void o2net_unregister_handler_list(struct list_head *list)
871 {
872         struct o2net_msg_handler *nmh, *n;
873 
874         write_lock(&o2net_handler_lock);
875         list_for_each_entry_safe(nmh, n, list, nh_unregister_item) {
876                 mlog(ML_TCP, "unregistering handler func %p type %u key %08x\n",
877                      nmh->nh_func, nmh->nh_msg_type, nmh->nh_key);
878                 rb_erase(&nmh->nh_node, &o2net_handler_tree);
879                 list_del_init(&nmh->nh_unregister_item);
880                 kref_put(&nmh->nh_kref, o2net_handler_kref_release);
881         }
882         write_unlock(&o2net_handler_lock);
883 }
884 EXPORT_SYMBOL_GPL(o2net_unregister_handler_list);
885 
886 static struct o2net_msg_handler *o2net_handler_get(u32 msg_type, u32 key)
887 {
888         struct o2net_msg_handler *nmh;
889 
890         read_lock(&o2net_handler_lock);
891         nmh = o2net_handler_tree_lookup(msg_type, key, NULL, NULL);
892         if (nmh)
893                 kref_get(&nmh->nh_kref);
894         read_unlock(&o2net_handler_lock);
895 
896         return nmh;
897 }
898 
899 /* ------------------------------------------------------------ */
900 
901 static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
902 {
903         struct kvec vec = { .iov_len = len, .iov_base = data, };
904         struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
905         iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, len);
906         return sock_recvmsg(sock, &msg, MSG_DONTWAIT);
907 }
908 
909 static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
910                               size_t veclen, size_t total)
911 {
912         int ret;
913         struct msghdr msg = {.msg_flags = 0,};
914 
915         if (sock == NULL) {
916                 ret = -EINVAL;
917                 goto out;
918         }
919 
920         ret = kernel_sendmsg(sock, &msg, vec, veclen, total);
921         if (likely(ret == total))
922                 return 0;
923         mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret, total);
924         if (ret >= 0)
925                 ret = -EPIPE; /* should be smarter, I bet */
926 out:
927         mlog(0, "returning error: %d\n", ret);
928         return ret;
929 }
930 
931 static void o2net_sendpage(struct o2net_sock_container *sc,
932                            void *kmalloced_virt,
933                            size_t size)
934 {
935         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
936         ssize_t ret;
937 
938         while (1) {
939                 mutex_lock(&sc->sc_send_lock);
940                 ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
941                                                  virt_to_page(kmalloced_virt),
942                                                  offset_in_page(kmalloced_virt),
943                                                  size, MSG_DONTWAIT);
944                 mutex_unlock(&sc->sc_send_lock);
945                 if (ret == size)
946                         break;
947                 if (ret == (ssize_t)-EAGAIN) {
948                         mlog(0, "sendpage of size %zu to " SC_NODEF_FMT
949                              " returned EAGAIN\n", size, SC_NODEF_ARGS(sc));
950                         cond_resched();
951                         continue;
952                 }
953                 mlog(ML_ERROR, "sendpage of size %zu to " SC_NODEF_FMT
954                      " failed with %zd\n", size, SC_NODEF_ARGS(sc), ret);
955                 o2net_ensure_shutdown(nn, sc, 0);
956                 break;
957         }
958 }
959 
960 static void o2net_init_msg(struct o2net_msg *msg, u16 data_len, u16 msg_type, u32 key)
961 {
962         memset(msg, 0, sizeof(struct o2net_msg));
963         msg->magic = cpu_to_be16(O2NET_MSG_MAGIC);
964         msg->data_len = cpu_to_be16(data_len);
965         msg->msg_type = cpu_to_be16(msg_type);
966         msg->sys_status = cpu_to_be32(O2NET_ERR_NONE);
967         msg->status = 0;
968         msg->key = cpu_to_be32(key);
969 }
970 
971 static int o2net_tx_can_proceed(struct o2net_node *nn,
972                                 struct o2net_sock_container **sc_ret,
973                                 int *error)
974 {
975         int ret = 0;
976 
977         spin_lock(&nn->nn_lock);
978         if (nn->nn_persistent_error) {
979                 ret = 1;
980                 *sc_ret = NULL;
981                 *error = nn->nn_persistent_error;
982         } else if (nn->nn_sc_valid) {
983                 kref_get(&nn->nn_sc->sc_kref);
984 
985                 ret = 1;
986                 *sc_ret = nn->nn_sc;
987                 *error = 0;
988         }
989         spin_unlock(&nn->nn_lock);
990 
991         return ret;
992 }
993 
994 /* Get a map of all nodes to which this node is currently connected to */
995 void o2net_fill_node_map(unsigned long *map, unsigned bytes)
996 {
997         struct o2net_sock_container *sc;
998         int node, ret;
999 
1000         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1001 
1002         memset(map, 0, bytes);
1003         for (node = 0; node < O2NM_MAX_NODES; ++node) {
1004                 if (!o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret))
1005                         continue;
1006                 if (!ret) {
1007                         set_bit(node, map);
1008                         sc_put(sc);
1009                 }
1010         }
1011 }
1012 EXPORT_SYMBOL_GPL(o2net_fill_node_map);
1013 
1014 int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
1015                            size_t caller_veclen, u8 target_node, int *status)
1016 {
1017         int ret = 0;
1018         struct o2net_msg *msg = NULL;
1019         size_t veclen, caller_bytes = 0;
1020         struct kvec *vec = NULL;
1021         struct o2net_sock_container *sc = NULL;
1022         struct o2net_node *nn = o2net_nn_from_num(target_node);
1023         struct o2net_status_wait nsw = {
1024                 .ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
1025         };
1026         struct o2net_send_tracking nst;
1027 
1028         o2net_init_nst(&nst, msg_type, key, current, target_node);
1029 
1030         if (o2net_wq == NULL) {
1031                 mlog(0, "attempt to tx without o2netd running\n");
1032                 ret = -ESRCH;
1033                 goto out;
1034         }
1035 
1036         if (caller_veclen == 0) {
1037                 mlog(0, "bad kvec array length\n");
1038                 ret = -EINVAL;
1039                 goto out;
1040         }
1041 
1042         caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
1043         if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
1044                 mlog(0, "total payload len %zu too large\n", caller_bytes);
1045                 ret = -EINVAL;
1046                 goto out;
1047         }
1048 
1049         if (target_node == o2nm_this_node()) {
1050                 ret = -ELOOP;
1051                 goto out;
1052         }
1053 
1054         o2net_debug_add_nst(&nst);
1055 
1056         o2net_set_nst_sock_time(&nst);
1057 
1058         wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
1059         if (ret)
1060                 goto out;
1061 
1062         o2net_set_nst_sock_container(&nst, sc);
1063 
1064         veclen = caller_veclen + 1;
1065         vec = kmalloc_array(veclen, sizeof(struct kvec), GFP_ATOMIC);
1066         if (vec == NULL) {
1067                 mlog(0, "failed to %zu element kvec!\n", veclen);
1068                 ret = -ENOMEM;
1069                 goto out;
1070         }
1071 
1072         msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
1073         if (!msg) {
1074                 mlog(0, "failed to allocate a o2net_msg!\n");
1075                 ret = -ENOMEM;
1076                 goto out;
1077         }
1078 
1079         o2net_init_msg(msg, caller_bytes, msg_type, key);
1080 
1081         vec[0].iov_len = sizeof(struct o2net_msg);
1082         vec[0].iov_base = msg;
1083         memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
1084 
1085         ret = o2net_prep_nsw(nn, &nsw);
1086         if (ret)
1087                 goto out;
1088 
1089         msg->msg_num = cpu_to_be32(nsw.ns_id);
1090         o2net_set_nst_msg_id(&nst, nsw.ns_id);
1091 
1092         o2net_set_nst_send_time(&nst);
1093 
1094         /* finally, convert the message header to network byte-order
1095          * and send */
1096         mutex_lock(&sc->sc_send_lock);
1097         ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
1098                                  sizeof(struct o2net_msg) + caller_bytes);
1099         mutex_unlock(&sc->sc_send_lock);
1100         msglog(msg, "sending returned %d\n", ret);
1101         if (ret < 0) {
1102                 mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
1103                 goto out;
1104         }
1105 
1106         /* wait on other node's handler */
1107         o2net_set_nst_status_time(&nst);
1108         wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
1109 
1110         o2net_update_send_stats(&nst, sc);
1111 
1112         /* Note that we avoid overwriting the callers status return
1113          * variable if a system error was reported on the other
1114          * side. Callers beware. */
1115         ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
1116         if (status && !ret)
1117                 *status = nsw.ns_status;
1118 
1119         mlog(0, "woken, returning system status %d, user status %d\n",
1120              ret, nsw.ns_status);
1121 out:
1122         o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
1123         if (sc)
1124                 sc_put(sc);
1125         kfree(vec);
1126         kfree(msg);
1127         o2net_complete_nsw(nn, &nsw, 0, 0, 0);
1128         return ret;
1129 }
1130 EXPORT_SYMBOL_GPL(o2net_send_message_vec);
1131 
1132 int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
1133                        u8 target_node, int *status)
1134 {
1135         struct kvec vec = {
1136                 .iov_base = data,
1137                 .iov_len = len,
1138         };
1139         return o2net_send_message_vec(msg_type, key, &vec, 1,
1140                                       target_node, status);
1141 }
1142 EXPORT_SYMBOL_GPL(o2net_send_message);
1143 
1144 static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
1145                                    enum o2net_system_error syserr, int err)
1146 {
1147         struct kvec vec = {
1148                 .iov_base = hdr,
1149                 .iov_len = sizeof(struct o2net_msg),
1150         };
1151 
1152         BUG_ON(syserr >= O2NET_ERR_MAX);
1153 
1154         /* leave other fields intact from the incoming message, msg_num
1155          * in particular */
1156         hdr->sys_status = cpu_to_be32(syserr);
1157         hdr->status = cpu_to_be32(err);
1158         hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
1159         hdr->data_len = 0;
1160 
1161         msglog(hdr, "about to send status magic %d\n", err);
1162         /* hdr has been in host byteorder this whole time */
1163         return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
1164 }
1165 
1166 /* this returns -errno if the header was unknown or too large, etc.
1167  * after this is called the buffer us reused for the next message */
1168 static int o2net_process_message(struct o2net_sock_container *sc,
1169                                  struct o2net_msg *hdr)
1170 {
1171         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1172         int ret = 0, handler_status;
1173         enum  o2net_system_error syserr;
1174         struct o2net_msg_handler *nmh = NULL;
1175         void *ret_data = NULL;
1176 
1177         msglog(hdr, "processing message\n");
1178 
1179         o2net_sc_postpone_idle(sc);
1180 
1181         switch(be16_to_cpu(hdr->magic)) {
1182                 case O2NET_MSG_STATUS_MAGIC:
1183                         /* special type for returning message status */
1184                         o2net_complete_nsw(nn, NULL,
1185                                            be32_to_cpu(hdr->msg_num),
1186                                            be32_to_cpu(hdr->sys_status),
1187                                            be32_to_cpu(hdr->status));
1188                         goto out;
1189                 case O2NET_MSG_KEEP_REQ_MAGIC:
1190                         o2net_sendpage(sc, o2net_keep_resp,
1191                                        sizeof(*o2net_keep_resp));
1192                         goto out;
1193                 case O2NET_MSG_KEEP_RESP_MAGIC:
1194                         goto out;
1195                 case O2NET_MSG_MAGIC:
1196                         break;
1197                 default:
1198                         msglog(hdr, "bad magic\n");
1199                         ret = -EINVAL;
1200                         goto out;
1201                         break;
1202         }
1203 
1204         /* find a handler for it */
1205         handler_status = 0;
1206         nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
1207                                 be32_to_cpu(hdr->key));
1208         if (!nmh) {
1209                 mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
1210                      be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
1211                 syserr = O2NET_ERR_NO_HNDLR;
1212                 goto out_respond;
1213         }
1214 
1215         syserr = O2NET_ERR_NONE;
1216 
1217         if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
1218                 syserr = O2NET_ERR_OVERFLOW;
1219 
1220         if (syserr != O2NET_ERR_NONE)
1221                 goto out_respond;
1222 
1223         o2net_set_func_start_time(sc);
1224         sc->sc_msg_key = be32_to_cpu(hdr->key);
1225         sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
1226         handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
1227                                              be16_to_cpu(hdr->data_len),
1228                                         nmh->nh_func_data, &ret_data);
1229         o2net_set_func_stop_time(sc);
1230 
1231         o2net_update_recv_stats(sc);
1232 
1233 out_respond:
1234         /* this destroys the hdr, so don't use it after this */
1235         mutex_lock(&sc->sc_send_lock);
1236         ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
1237                                       handler_status);
1238         mutex_unlock(&sc->sc_send_lock);
1239         hdr = NULL;
1240         mlog(0, "sending handler status %d, syserr %d returned %d\n",
1241              handler_status, syserr, ret);
1242 
1243         if (nmh) {
1244                 BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
1245                 if (nmh->nh_post_func)
1246                         (nmh->nh_post_func)(handler_status, nmh->nh_func_data,
1247                                             ret_data);
1248         }
1249 
1250 out:
1251         if (nmh)
1252                 o2net_handler_put(nmh);
1253         return ret;
1254 }
1255 
1256 static int o2net_check_handshake(struct o2net_sock_container *sc)
1257 {
1258         struct o2net_handshake *hand = page_address(sc->sc_page);
1259         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1260 
1261         if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
1262                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
1263                        "protocol version %llu but %llu is required. "
1264                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1265                        (unsigned long long)be64_to_cpu(hand->protocol_version),
1266                        O2NET_PROTOCOL_VERSION);
1267 
1268                 /* don't bother reconnecting if its the wrong version. */
1269                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1270                 return -1;
1271         }
1272 
1273         /*
1274          * Ensure timeouts are consistent with other nodes, otherwise
1275          * we can end up with one node thinking that the other must be down,
1276          * but isn't. This can ultimately cause corruption.
1277          */
1278         if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
1279                                 o2net_idle_timeout()) {
1280                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
1281                        "idle timeout of %u ms, but we use %u ms locally. "
1282                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1283                        be32_to_cpu(hand->o2net_idle_timeout_ms),
1284                        o2net_idle_timeout());
1285                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1286                 return -1;
1287         }
1288 
1289         if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
1290                         o2net_keepalive_delay()) {
1291                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
1292                        "delay of %u ms, but we use %u ms locally. "
1293                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1294                        be32_to_cpu(hand->o2net_keepalive_delay_ms),
1295                        o2net_keepalive_delay());
1296                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1297                 return -1;
1298         }
1299 
1300         if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
1301                         O2HB_MAX_WRITE_TIMEOUT_MS) {
1302                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
1303                        "timeout of %u ms, but we use %u ms locally. "
1304                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1305                        be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
1306                        O2HB_MAX_WRITE_TIMEOUT_MS);
1307                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1308                 return -1;
1309         }
1310 
1311         sc->sc_handshake_ok = 1;
1312 
1313         spin_lock(&nn->nn_lock);
1314         /* set valid and queue the idle timers only if it hasn't been
1315          * shut down already */
1316         if (nn->nn_sc == sc) {
1317                 o2net_sc_reset_idle_timer(sc);
1318                 atomic_set(&nn->nn_timeout, 0);
1319                 o2net_set_nn_state(nn, sc, 1, 0);
1320         }
1321         spin_unlock(&nn->nn_lock);
1322 
1323         /* shift everything up as though it wasn't there */
1324         sc->sc_page_off -= sizeof(struct o2net_handshake);
1325         if (sc->sc_page_off)
1326                 memmove(hand, hand + 1, sc->sc_page_off);
1327 
1328         return 0;
1329 }
1330 
1331 /* this demuxes the queued rx bytes into header or payload bits and calls
1332  * handlers as each full message is read off the socket.  it returns -error,
1333  * == 0 eof, or > 0 for progress made.*/
1334 static int o2net_advance_rx(struct o2net_sock_container *sc)
1335 {
1336         struct o2net_msg *hdr;
1337         int ret = 0;
1338         void *data;
1339         size_t datalen;
1340 
1341         sclog(sc, "receiving\n");
1342         o2net_set_advance_start_time(sc);
1343 
1344         if (unlikely(sc->sc_handshake_ok == 0)) {
1345                 if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
1346                         data = page_address(sc->sc_page) + sc->sc_page_off;
1347                         datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
1348                         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1349                         if (ret > 0)
1350                                 sc->sc_page_off += ret;
1351                 }
1352 
1353                 if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
1354                         o2net_check_handshake(sc);
1355                         if (unlikely(sc->sc_handshake_ok == 0))
1356                                 ret = -EPROTO;
1357                 }
1358                 goto out;
1359         }
1360 
1361         /* do we need more header? */
1362         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1363                 data = page_address(sc->sc_page) + sc->sc_page_off;
1364                 datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
1365                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1366                 if (ret > 0) {
1367                         sc->sc_page_off += ret;
1368                         /* only swab incoming here.. we can
1369                          * only get here once as we cross from
1370                          * being under to over */
1371                         if (sc->sc_page_off == sizeof(struct o2net_msg)) {
1372                                 hdr = page_address(sc->sc_page);
1373                                 if (be16_to_cpu(hdr->data_len) >
1374                                     O2NET_MAX_PAYLOAD_BYTES)
1375                                         ret = -EOVERFLOW;
1376                         }
1377                 }
1378                 if (ret <= 0)
1379                         goto out;
1380         }
1381 
1382         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1383                 /* oof, still don't have a header */
1384                 goto out;
1385         }
1386 
1387         /* this was swabbed above when we first read it */
1388         hdr = page_address(sc->sc_page);
1389 
1390         msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
1391 
1392         /* do we need more payload? */
1393         if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
1394                 /* need more payload */
1395                 data = page_address(sc->sc_page) + sc->sc_page_off;
1396                 datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
1397                           sc->sc_page_off;
1398                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1399                 if (ret > 0)
1400                         sc->sc_page_off += ret;
1401                 if (ret <= 0)
1402                         goto out;
1403         }
1404 
1405         if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
1406                 /* we can only get here once, the first time we read
1407                  * the payload.. so set ret to progress if the handler
1408                  * works out. after calling this the message is toast */
1409                 ret = o2net_process_message(sc, hdr);
1410                 if (ret == 0)
1411                         ret = 1;
1412                 sc->sc_page_off = 0;
1413         }
1414 
1415 out:
1416         sclog(sc, "ret = %d\n", ret);
1417         o2net_set_advance_stop_time(sc);
1418         return ret;
1419 }
1420 
1421 /* this work func is triggerd by data ready.  it reads until it can read no
1422  * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
1423  * our work the work struct will be marked and we'll be called again. */
1424 static void o2net_rx_until_empty(struct work_struct *work)
1425 {
1426         struct o2net_sock_container *sc =
1427                 container_of(work, struct o2net_sock_container, sc_rx_work);
1428         int ret;
1429 
1430         do {
1431                 ret = o2net_advance_rx(sc);
1432         } while (ret > 0);
1433 
1434         if (ret <= 0 && ret != -EAGAIN) {
1435                 struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1436                 sclog(sc, "saw error %d, closing\n", ret);
1437                 /* not permanent so read failed handshake can retry */
1438                 o2net_ensure_shutdown(nn, sc, 0);
1439         }
1440 
1441         sc_put(sc);
1442 }
1443 
1444 static int o2net_set_nodelay(struct socket *sock)
1445 {
1446         int val = 1;
1447 
1448         return kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
1449                                     (void *)&val, sizeof(val));
1450 }
1451 
1452 static int o2net_set_usertimeout(struct socket *sock)
1453 {
1454         int user_timeout = O2NET_TCP_USER_TIMEOUT;
1455 
1456         return kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
1457                                 (void *)&user_timeout, sizeof(user_timeout));
1458 }
1459 
1460 static void o2net_initialize_handshake(void)
1461 {
1462         o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
1463                 O2HB_MAX_WRITE_TIMEOUT_MS);
1464         o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
1465         o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
1466                 o2net_keepalive_delay());
1467         o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
1468                 o2net_reconnect_delay());
1469 }
1470 
1471 /* ------------------------------------------------------------ */
1472 
1473 /* called when a connect completes and after a sock is accepted.  the
1474  * rx path will see the response and mark the sc valid */
1475 static void o2net_sc_connect_completed(struct work_struct *work)
1476 {
1477         struct o2net_sock_container *sc =
1478                 container_of(work, struct o2net_sock_container,
1479                              sc_connect_work);
1480 
1481         mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
1482               (unsigned long long)O2NET_PROTOCOL_VERSION,
1483               (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
1484 
1485         o2net_initialize_handshake();
1486         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1487         sc_put(sc);
1488 }
1489 
1490 /* this is called as a work_struct func. */
1491 static void o2net_sc_send_keep_req(struct work_struct *work)
1492 {
1493         struct o2net_sock_container *sc =
1494                 container_of(work, struct o2net_sock_container,
1495                              sc_keepalive_work.work);
1496 
1497         o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
1498         sc_put(sc);
1499 }
1500 
1501 /* socket shutdown does a del_timer_sync against this as it tears down.
1502  * we can't start this timer until we've got to the point in sc buildup
1503  * where shutdown is going to be involved */
1504 static void o2net_idle_timer(struct timer_list *t)
1505 {
1506         struct o2net_sock_container *sc = from_timer(sc, t, sc_idle_timeout);
1507         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1508 #ifdef CONFIG_DEBUG_FS
1509         unsigned long msecs = ktime_to_ms(ktime_get()) -
1510                 ktime_to_ms(sc->sc_tv_timer);
1511 #else
1512         unsigned long msecs = o2net_idle_timeout();
1513 #endif
1514 
1515         printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
1516                "idle for %lu.%lu secs.\n",
1517                SC_NODEF_ARGS(sc), msecs / 1000, msecs % 1000);
1518 
1519         /* idle timerout happen, don't shutdown the connection, but
1520          * make fence decision. Maybe the connection can recover before
1521          * the decision is made.
1522          */
1523         atomic_set(&nn->nn_timeout, 1);
1524         o2quo_conn_err(o2net_num_from_nn(nn));
1525         queue_delayed_work(o2net_wq, &nn->nn_still_up,
1526                         msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
1527 
1528         o2net_sc_reset_idle_timer(sc);
1529 
1530 }
1531 
1532 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
1533 {
1534         o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
1535         o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
1536                       msecs_to_jiffies(o2net_keepalive_delay()));
1537         o2net_set_sock_timer(sc);
1538         mod_timer(&sc->sc_idle_timeout,
1539                jiffies + msecs_to_jiffies(o2net_idle_timeout()));
1540 }
1541 
1542 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
1543 {
1544         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1545 
1546         /* clear fence decision since the connection recover from timeout*/
1547         if (atomic_read(&nn->nn_timeout)) {
1548                 o2quo_conn_up(o2net_num_from_nn(nn));
1549                 cancel_delayed_work(&nn->nn_still_up);
1550                 atomic_set(&nn->nn_timeout, 0);
1551         }
1552 
1553         /* Only push out an existing timer */
1554         if (timer_pending(&sc->sc_idle_timeout))
1555                 o2net_sc_reset_idle_timer(sc);
1556 }
1557 
1558 /* this work func is kicked whenever a path sets the nn state which doesn't
1559  * have valid set.  This includes seeing hb come up, losing a connection,
1560  * having a connect attempt fail, etc. This centralizes the logic which decides
1561  * if a connect attempt should be made or if we should give up and all future
1562  * transmit attempts should fail */
1563 static void o2net_start_connect(struct work_struct *work)
1564 {
1565         struct o2net_node *nn =
1566                 container_of(work, struct o2net_node, nn_connect_work.work);
1567         struct o2net_sock_container *sc = NULL;
1568         struct o2nm_node *node = NULL, *mynode = NULL;
1569         struct socket *sock = NULL;
1570         struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
1571         int ret = 0, stop;
1572         unsigned int timeout;
1573         unsigned int noio_flag;
1574 
1575         /*
1576          * sock_create allocates the sock with GFP_KERNEL. We must set
1577          * per-process flag PF_MEMALLOC_NOIO so that all allocations done
1578          * by this process are done as if GFP_NOIO was specified. So we
1579          * are not reentering filesystem while doing memory reclaim.
1580          */
1581         noio_flag = memalloc_noio_save();
1582         /* if we're greater we initiate tx, otherwise we accept */
1583         if (o2nm_this_node() <= o2net_num_from_nn(nn))
1584                 goto out;
1585 
1586         /* watch for racing with tearing a node down */
1587         node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
1588         if (node == NULL)
1589                 goto out;
1590 
1591         mynode = o2nm_get_node_by_num(o2nm_this_node());
1592         if (mynode == NULL)
1593                 goto out;
1594 
1595         spin_lock(&nn->nn_lock);
1596         /*
1597          * see if we already have one pending or have given up.
1598          * For nn_timeout, it is set when we close the connection
1599          * because of the idle time out. So it means that we have
1600          * at least connected to that node successfully once,
1601          * now try to connect to it again.
1602          */
1603         timeout = atomic_read(&nn->nn_timeout);
1604         stop = (nn->nn_sc ||
1605                 (nn->nn_persistent_error &&
1606                 (nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
1607         spin_unlock(&nn->nn_lock);
1608         if (stop)
1609                 goto out;
1610 
1611         nn->nn_last_connect_attempt = jiffies;
1612 
1613         sc = sc_alloc(node);
1614         if (sc == NULL) {
1615                 mlog(0, "couldn't allocate sc\n");
1616                 ret = -ENOMEM;
1617                 goto out;
1618         }
1619 
1620         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1621         if (ret < 0) {
1622                 mlog(0, "can't create socket: %d\n", ret);
1623                 goto out;
1624         }
1625         sc->sc_sock = sock; /* freed by sc_kref_release */
1626 
1627         sock->sk->sk_allocation = GFP_ATOMIC;
1628 
1629         myaddr.sin_family = AF_INET;
1630         myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
1631         myaddr.sin_port = htons(0); /* any port */
1632 
1633         ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
1634                               sizeof(myaddr));
1635         if (ret) {
1636                 mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
1637                      ret, &mynode->nd_ipv4_address);
1638                 goto out;
1639         }
1640 
1641         ret = o2net_set_nodelay(sc->sc_sock);
1642         if (ret) {
1643                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1644                 goto out;
1645         }
1646 
1647         ret = o2net_set_usertimeout(sock);
1648         if (ret) {
1649                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1650                 goto out;
1651         }
1652 
1653         o2net_register_callbacks(sc->sc_sock->sk, sc);
1654 
1655         spin_lock(&nn->nn_lock);
1656         /* handshake completion will set nn->nn_sc_valid */
1657         o2net_set_nn_state(nn, sc, 0, 0);
1658         spin_unlock(&nn->nn_lock);
1659 
1660         remoteaddr.sin_family = AF_INET;
1661         remoteaddr.sin_addr.s_addr = node->nd_ipv4_address;
1662         remoteaddr.sin_port = node->nd_ipv4_port;
1663 
1664         ret = sc->sc_sock->ops->connect(sc->sc_sock,
1665                                         (struct sockaddr *)&remoteaddr,
1666                                         sizeof(remoteaddr),
1667                                         O_NONBLOCK);
1668         if (ret == -EINPROGRESS)
1669                 ret = 0;
1670 
1671 out:
1672         if (ret && sc) {
1673                 printk(KERN_NOTICE "o2net: Connect attempt to " SC_NODEF_FMT
1674                        " failed with errno %d\n", SC_NODEF_ARGS(sc), ret);
1675                 /* 0 err so that another will be queued and attempted
1676                  * from set_nn_state */
1677                 o2net_ensure_shutdown(nn, sc, 0);
1678         }
1679         if (sc)
1680                 sc_put(sc);
1681         if (node)
1682                 o2nm_node_put(node);
1683         if (mynode)
1684                 o2nm_node_put(mynode);
1685 
1686         memalloc_noio_restore(noio_flag);
1687         return;
1688 }
1689 
1690 static void o2net_connect_expired(struct work_struct *work)
1691 {
1692         struct o2net_node *nn =
1693                 container_of(work, struct o2net_node, nn_connect_expired.work);
1694 
1695         spin_lock(&nn->nn_lock);
1696         if (!nn->nn_sc_valid) {
1697                 printk(KERN_NOTICE "o2net: No connection established with "
1698                        "node %u after %u.%u seconds, check network and"
1699                        " cluster configuration.\n",
1700                      o2net_num_from_nn(nn),
1701                      o2net_idle_timeout() / 1000,
1702                      o2net_idle_timeout() % 1000);
1703 
1704                 o2net_set_nn_state(nn, NULL, 0, 0);
1705         }
1706         spin_unlock(&nn->nn_lock);
1707 }
1708 
1709 static void o2net_still_up(struct work_struct *work)
1710 {
1711         struct o2net_node *nn =
1712                 container_of(work, struct o2net_node, nn_still_up.work);
1713 
1714         o2quo_hb_still_up(o2net_num_from_nn(nn));
1715 }
1716 
1717 /* ------------------------------------------------------------ */
1718 
1719 void o2net_disconnect_node(struct o2nm_node *node)
1720 {
1721         struct o2net_node *nn = o2net_nn_from_num(node->nd_num);
1722 
1723         /* don't reconnect until it's heartbeating again */
1724         spin_lock(&nn->nn_lock);
1725         atomic_set(&nn->nn_timeout, 0);
1726         o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
1727         spin_unlock(&nn->nn_lock);
1728 
1729         if (o2net_wq) {
1730                 cancel_delayed_work(&nn->nn_connect_expired);
1731                 cancel_delayed_work(&nn->nn_connect_work);
1732                 cancel_delayed_work(&nn->nn_still_up);
1733                 flush_workqueue(o2net_wq);
1734         }
1735 }
1736 
1737 static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
1738                                   void *data)
1739 {
1740         o2quo_hb_down(node_num);
1741 
1742         if (!node)
1743                 return;
1744 
1745         if (node_num != o2nm_this_node())
1746                 o2net_disconnect_node(node);
1747 
1748         BUG_ON(atomic_read(&o2net_connected_peers) < 0);
1749 }
1750 
1751 static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
1752                                 void *data)
1753 {
1754         struct o2net_node *nn = o2net_nn_from_num(node_num);
1755 
1756         o2quo_hb_up(node_num);
1757 
1758         BUG_ON(!node);
1759 
1760         /* ensure an immediate connect attempt */
1761         nn->nn_last_connect_attempt = jiffies -
1762                 (msecs_to_jiffies(o2net_reconnect_delay()) + 1);
1763 
1764         if (node_num != o2nm_this_node()) {
1765                 /* believe it or not, accept and node heartbeating testing
1766                  * can succeed for this node before we got here.. so
1767                  * only use set_nn_state to clear the persistent error
1768                  * if that hasn't already happened */
1769                 spin_lock(&nn->nn_lock);
1770                 atomic_set(&nn->nn_timeout, 0);
1771                 if (nn->nn_persistent_error)
1772                         o2net_set_nn_state(nn, NULL, 0, 0);
1773                 spin_unlock(&nn->nn_lock);
1774         }
1775 }
1776 
1777 void o2net_unregister_hb_callbacks(void)
1778 {
1779         o2hb_unregister_callback(NULL, &o2net_hb_up);
1780         o2hb_unregister_callback(NULL, &o2net_hb_down);
1781 }
1782 
1783 int o2net_register_hb_callbacks(void)
1784 {
1785         int ret;
1786 
1787         o2hb_setup_callback(&o2net_hb_down, O2HB_NODE_DOWN_CB,
1788                             o2net_hb_node_down_cb, NULL, O2NET_HB_PRI);
1789         o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
1790                             o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
1791 
1792         ret = o2hb_register_callback(NULL, &o2net_hb_up);
1793         if (ret == 0)
1794                 ret = o2hb_register_callback(NULL, &o2net_hb_down);
1795 
1796         if (ret)
1797                 o2net_unregister_hb_callbacks();
1798 
1799         return ret;
1800 }
1801 
1802 /* ------------------------------------------------------------ */
1803 
1804 static int o2net_accept_one(struct socket *sock, int *more)
1805 {
1806         int ret;
1807         struct sockaddr_in sin;
1808         struct socket *new_sock = NULL;
1809         struct o2nm_node *node = NULL;
1810         struct o2nm_node *local_node = NULL;
1811         struct o2net_sock_container *sc = NULL;
1812         struct o2net_node *nn;
1813         unsigned int noio_flag;
1814 
1815         /*
1816          * sock_create_lite allocates the sock with GFP_KERNEL. We must set
1817          * per-process flag PF_MEMALLOC_NOIO so that all allocations done
1818          * by this process are done as if GFP_NOIO was specified. So we
1819          * are not reentering filesystem while doing memory reclaim.
1820          */
1821         noio_flag = memalloc_noio_save();
1822 
1823         BUG_ON(sock == NULL);
1824         *more = 0;
1825         ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
1826                                sock->sk->sk_protocol, &new_sock);
1827         if (ret)
1828                 goto out;
1829 
1830         new_sock->type = sock->type;
1831         new_sock->ops = sock->ops;
1832         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK, false);
1833         if (ret < 0)
1834                 goto out;
1835 
1836         *more = 1;
1837         new_sock->sk->sk_allocation = GFP_ATOMIC;
1838 
1839         ret = o2net_set_nodelay(new_sock);
1840         if (ret) {
1841                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1842                 goto out;
1843         }
1844 
1845         ret = o2net_set_usertimeout(new_sock);
1846         if (ret) {
1847                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1848                 goto out;
1849         }
1850 
1851         ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin, 1);
1852         if (ret < 0)
1853                 goto out;
1854 
1855         node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
1856         if (node == NULL) {
1857                 printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
1858                        "node at %pI4:%d\n", &sin.sin_addr.s_addr,
1859                        ntohs(sin.sin_port));
1860                 ret = -EINVAL;
1861                 goto out;
1862         }
1863 
1864         if (o2nm_this_node() >= node->nd_num) {
1865                 local_node = o2nm_get_node_by_num(o2nm_this_node());
1866                 if (local_node)
1867                         printk(KERN_NOTICE "o2net: Unexpected connect attempt "
1868                                         "seen at node '%s' (%u, %pI4:%d) from "
1869                                         "node '%s' (%u, %pI4:%d)\n",
1870                                         local_node->nd_name, local_node->nd_num,
1871                                         &(local_node->nd_ipv4_address),
1872                                         ntohs(local_node->nd_ipv4_port),
1873                                         node->nd_name,
1874                                         node->nd_num, &sin.sin_addr.s_addr,
1875                                         ntohs(sin.sin_port));
1876                 ret = -EINVAL;
1877                 goto out;
1878         }
1879 
1880         /* this happens all the time when the other node sees our heartbeat
1881          * and tries to connect before we see their heartbeat */
1882         if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
1883                 mlog(ML_CONN, "attempt to connect from node '%s' at "
1884                      "%pI4:%d but it isn't heartbeating\n",
1885                      node->nd_name, &sin.sin_addr.s_addr,
1886                      ntohs(sin.sin_port));
1887                 ret = -EINVAL;
1888                 goto out;
1889         }
1890 
1891         nn = o2net_nn_from_num(node->nd_num);
1892 
1893         spin_lock(&nn->nn_lock);
1894         if (nn->nn_sc)
1895                 ret = -EBUSY;
1896         else
1897                 ret = 0;
1898         spin_unlock(&nn->nn_lock);
1899         if (ret) {
1900                 printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
1901                        "at %pI4:%d but it already has an open connection\n",
1902                        node->nd_name, &sin.sin_addr.s_addr,
1903                        ntohs(sin.sin_port));
1904                 goto out;
1905         }
1906 
1907         sc = sc_alloc(node);
1908         if (sc == NULL) {
1909                 ret = -ENOMEM;
1910                 goto out;
1911         }
1912 
1913         sc->sc_sock = new_sock;
1914         new_sock = NULL;
1915 
1916         spin_lock(&nn->nn_lock);
1917         atomic_set(&nn->nn_timeout, 0);
1918         o2net_set_nn_state(nn, sc, 0, 0);
1919         spin_unlock(&nn->nn_lock);
1920 
1921         o2net_register_callbacks(sc->sc_sock->sk, sc);
1922         o2net_sc_queue_work(sc, &sc->sc_rx_work);
1923 
1924         o2net_initialize_handshake();
1925         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1926 
1927 out:
1928         if (new_sock)
1929                 sock_release(new_sock);
1930         if (node)
1931                 o2nm_node_put(node);
1932         if (local_node)
1933                 o2nm_node_put(local_node);
1934         if (sc)
1935                 sc_put(sc);
1936 
1937         memalloc_noio_restore(noio_flag);
1938         return ret;
1939 }
1940 
1941 /*
1942  * This function is invoked in response to one or more
1943  * pending accepts at softIRQ level. We must drain the
1944  * entire que before returning.
1945  */
1946 
1947 static void o2net_accept_many(struct work_struct *work)
1948 {
1949         struct socket *sock = o2net_listen_sock;
1950         int     more;
1951         int     err;
1952 
1953         /*
1954          * It is critical to note that due to interrupt moderation
1955          * at the network driver level, we can't assume to get a
1956          * softIRQ for every single conn since tcp SYN packets
1957          * can arrive back-to-back, and therefore many pending
1958          * accepts may result in just 1 softIRQ. If we terminate
1959          * the o2net_accept_one() loop upon seeing an err, what happens
1960          * to the rest of the conns in the queue? If no new SYN
1961          * arrives for hours, no softIRQ  will be delivered,
1962          * and the connections will just sit in the queue.
1963          */
1964 
1965         for (;;) {
1966                 err = o2net_accept_one(sock, &more);
1967                 if (!more)
1968                         break;
1969                 cond_resched();
1970         }
1971 }
1972 
1973 static void o2net_listen_data_ready(struct sock *sk)
1974 {
1975         void (*ready)(struct sock *sk);
1976 
1977         read_lock_bh(&sk->sk_callback_lock);
1978         ready = sk->sk_user_data;
1979         if (ready == NULL) { /* check for teardown race */
1980                 ready = sk->sk_data_ready;
1981                 goto out;
1982         }
1983 
1984         /* This callback may called twice when a new connection
1985          * is  being established as a child socket inherits everything
1986          * from a parent LISTEN socket, including the data_ready cb of
1987          * the parent. This leads to a hazard. In o2net_accept_one()
1988          * we are still initializing the child socket but have not
1989          * changed the inherited data_ready callback yet when
1990          * data starts arriving.
1991          * We avoid this hazard by checking the state.
1992          * For the listening socket,  the state will be TCP_LISTEN; for the new
1993          * socket, will be  TCP_ESTABLISHED. Also, in this case,
1994          * sk->sk_user_data is not a valid function pointer.
1995          */
1996 
1997         if (sk->sk_state == TCP_LISTEN) {
1998                 queue_work(o2net_wq, &o2net_listen_work);
1999         } else {
2000                 ready = NULL;
2001         }
2002 
2003 out:
2004         read_unlock_bh(&sk->sk_callback_lock);
2005         if (ready != NULL)
2006                 ready(sk);
2007 }
2008 
2009 static int o2net_open_listening_sock(__be32 addr, __be16 port)
2010 {
2011         struct socket *sock = NULL;
2012         int ret;
2013         struct sockaddr_in sin = {
2014                 .sin_family = PF_INET,
2015                 .sin_addr = { .s_addr = addr },
2016                 .sin_port = port,
2017         };
2018 
2019         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
2020         if (ret < 0) {
2021                 printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
2022                 goto out;
2023         }
2024 
2025         sock->sk->sk_allocation = GFP_ATOMIC;
2026 
2027         write_lock_bh(&sock->sk->sk_callback_lock);
2028         sock->sk->sk_user_data = sock->sk->sk_data_ready;
2029         sock->sk->sk_data_ready = o2net_listen_data_ready;
2030         write_unlock_bh(&sock->sk->sk_callback_lock);
2031 
2032         o2net_listen_sock = sock;
2033         INIT_WORK(&o2net_listen_work, o2net_accept_many);
2034 
2035         sock->sk->sk_reuse = SK_CAN_REUSE;
2036         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
2037         if (ret < 0) {
2038                 printk(KERN_ERR "o2net: Error %d while binding socket at "
2039                        "%pI4:%u\n", ret, &addr, ntohs(port)); 
2040                 goto out;
2041         }
2042 
2043         ret = sock->ops->listen(sock, 64);
2044         if (ret < 0)
2045                 printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
2046                        ret, &addr, ntohs(port));
2047 
2048 out:
2049         if (ret) {
2050                 o2net_listen_sock = NULL;
2051                 if (sock)
2052                         sock_release(sock);
2053         }
2054         return ret;
2055 }
2056 
2057 /*
2058  * called from node manager when we should bring up our network listening
2059  * socket.  node manager handles all the serialization to only call this
2060  * once and to match it with o2net_stop_listening().  note,
2061  * o2nm_this_node() doesn't work yet as we're being called while it
2062  * is being set up.
2063  */
2064 int o2net_start_listening(struct o2nm_node *node)
2065 {
2066         int ret = 0;
2067 
2068         BUG_ON(o2net_wq != NULL);
2069         BUG_ON(o2net_listen_sock != NULL);
2070 
2071         mlog(ML_KTHREAD, "starting o2net thread...\n");
2072         o2net_wq = alloc_ordered_workqueue("o2net", WQ_MEM_RECLAIM);
2073         if (o2net_wq == NULL) {
2074                 mlog(ML_ERROR, "unable to launch o2net thread\n");
2075                 return -ENOMEM; /* ? */
2076         }
2077 
2078         ret = o2net_open_listening_sock(node->nd_ipv4_address,
2079                                         node->nd_ipv4_port);
2080         if (ret) {
2081                 destroy_workqueue(o2net_wq);
2082                 o2net_wq = NULL;
2083         } else
2084                 o2quo_conn_up(node->nd_num);
2085 
2086         return ret;
2087 }
2088 
2089 /* again, o2nm_this_node() doesn't work here as we're involved in
2090  * tearing it down */
2091 void o2net_stop_listening(struct o2nm_node *node)
2092 {
2093         struct socket *sock = o2net_listen_sock;
2094         size_t i;
2095 
2096         BUG_ON(o2net_wq == NULL);
2097         BUG_ON(o2net_listen_sock == NULL);
2098 
2099         /* stop the listening socket from generating work */
2100         write_lock_bh(&sock->sk->sk_callback_lock);
2101         sock->sk->sk_data_ready = sock->sk->sk_user_data;
2102         sock->sk->sk_user_data = NULL;
2103         write_unlock_bh(&sock->sk->sk_callback_lock);
2104 
2105         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2106                 struct o2nm_node *node = o2nm_get_node_by_num(i);
2107                 if (node) {
2108                         o2net_disconnect_node(node);
2109                         o2nm_node_put(node);
2110                 }
2111         }
2112 
2113         /* finish all work and tear down the work queue */
2114         mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
2115         destroy_workqueue(o2net_wq);
2116         o2net_wq = NULL;
2117 
2118         sock_release(o2net_listen_sock);
2119         o2net_listen_sock = NULL;
2120 
2121         o2quo_conn_err(node->nd_num);
2122 }
2123 
2124 /* ------------------------------------------------------------ */
2125 
2126 int o2net_init(void)
2127 {
2128         unsigned long i;
2129 
2130         o2quo_init();
2131 
2132         o2net_debugfs_init();
2133 
2134         o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
2135         o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2136         o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2137         if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp)
2138                 goto out;
2139 
2140         o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
2141         o2net_hand->connector_id = cpu_to_be64(1);
2142 
2143         o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
2144         o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
2145 
2146         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2147                 struct o2net_node *nn = o2net_nn_from_num(i);
2148 
2149                 atomic_set(&nn->nn_timeout, 0);
2150                 spin_lock_init(&nn->nn_lock);
2151                 INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
2152                 INIT_DELAYED_WORK(&nn->nn_connect_expired,
2153                                   o2net_connect_expired);
2154                 INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
2155                 /* until we see hb from a node we'll return einval */
2156                 nn->nn_persistent_error = -ENOTCONN;
2157                 init_waitqueue_head(&nn->nn_sc_wq);
2158                 idr_init(&nn->nn_status_idr);
2159                 INIT_LIST_HEAD(&nn->nn_status_list);
2160         }
2161 
2162         return 0;
2163 
2164 out:
2165         kfree(o2net_hand);
2166         kfree(o2net_keep_req);
2167         kfree(o2net_keep_resp);
2168         o2net_debugfs_exit();
2169         o2quo_exit();
2170         return -ENOMEM;
2171 }
2172 
2173 void o2net_exit(void)
2174 {
2175         o2quo_exit();
2176         kfree(o2net_hand);
2177         kfree(o2net_keep_req);
2178         kfree(o2net_keep_resp);
2179         o2net_debugfs_exit();
2180 }
2181 

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