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

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /* -*- mode: c; c-basic-offset: 8; -*-
  2  *
  3  * vim: noexpandtab sw=8 ts=8 sts=0:
  4  *
  5  * Copyright (C) 2004 Oracle.  All rights reserved.
  6  *
  7  * This program is free software; you can redistribute it and/or
  8  * modify it under the terms of the GNU General Public
  9  * License as published by the Free Software Foundation; either
 10  * version 2 of the License, or (at your option) any later version.
 11  *
 12  * This program is distributed in the hope that it will be useful,
 13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 15  * General Public License for more details.
 16  *
 17  * You should have received a copy of the GNU General Public
 18  * License along with this program; if not, write to the
 19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 20  * Boston, MA 021110-1307, USA.
 21  *
 22  * ----
 23  *
 24  * Callers for this were originally written against a very simple synchronus
 25  * API.  This implementation reflects those simple callers.  Some day I'm sure
 26  * we'll need to move to a more robust posting/callback mechanism.
 27  *
 28  * Transmit calls pass in kernel virtual addresses and block copying this into
 29  * the socket's tx buffers via a usual blocking sendmsg.  They'll block waiting
 30  * for a failed socket to timeout.  TX callers can also pass in a poniter to an
 31  * 'int' which gets filled with an errno off the wire in response to the
 32  * message they send.
 33  *
 34  * Handlers for unsolicited messages are registered.  Each socket has a page
 35  * that incoming data is copied into.  First the header, then the data.
 36  * Handlers are called from only one thread with a reference to this per-socket
 37  * page.  This page is destroyed after the handler call, so it can't be
 38  * referenced beyond the call.  Handlers may block but are discouraged from
 39  * doing so.
 40  *
 41  * Any framing errors (bad magic, large payload lengths) close a connection.
 42  *
 43  * Our sock_container holds the state we associate with a socket.  It's current
 44  * framing state is held there as well as the refcounting we do around when it
 45  * is safe to tear down the socket.  The socket is only finally torn down from
 46  * the container when the container loses all of its references -- so as long
 47  * as you hold a ref on the container you can trust that the socket is valid
 48  * for use with kernel socket APIs.
 49  *
 50  * Connections are initiated between a pair of nodes when the node with the
 51  * higher node number gets a heartbeat callback which indicates that the lower
 52  * numbered node has started heartbeating.  The lower numbered node is passive
 53  * and only accepts the connection if the higher numbered node is heartbeating.
 54  */
 55 
 56 #include <linux/kernel.h>
 57 #include <linux/jiffies.h>
 58 #include <linux/slab.h>
 59 #include <linux/idr.h>
 60 #include <linux/kref.h>
 61 #include <linux/net.h>
 62 #include <linux/export.h>
 63 #include <net/tcp.h>
 64 
 65 #include <asm/uaccess.h>
 66 
 67 #include "heartbeat.h"
 68 #include "tcp.h"
 69 #include "nodemanager.h"
 70 #define MLOG_MASK_PREFIX ML_TCP
 71 #include "masklog.h"
 72 #include "quorum.h"
 73 
 74 #include "tcp_internal.h"
 75 
 76 #define SC_NODEF_FMT "node %s (num %u) at %pI4:%u"
 77 #define SC_NODEF_ARGS(sc) sc->sc_node->nd_name, sc->sc_node->nd_num,    \
 78                           &sc->sc_node->nd_ipv4_address,                \
 79                           ntohs(sc->sc_node->nd_ipv4_port)
 80 
 81 /*
 82  * In the following two log macros, the whitespace after the ',' just
 83  * before ##args is intentional. Otherwise, gcc 2.95 will eat the
 84  * previous token if args expands to nothing.
 85  */
 86 #define msglog(hdr, fmt, args...) do {                                  \
 87         typeof(hdr) __hdr = (hdr);                                      \
 88         mlog(ML_MSG, "[mag %u len %u typ %u stat %d sys_stat %d "       \
 89              "key %08x num %u] " fmt,                                   \
 90              be16_to_cpu(__hdr->magic), be16_to_cpu(__hdr->data_len),   \
 91              be16_to_cpu(__hdr->msg_type), be32_to_cpu(__hdr->status),  \
 92              be32_to_cpu(__hdr->sys_status), be32_to_cpu(__hdr->key),   \
 93              be32_to_cpu(__hdr->msg_num) ,  ##args);                    \
 94 } while (0)
 95 
 96 #define sclog(sc, fmt, args...) do {                                    \
 97         typeof(sc) __sc = (sc);                                         \
 98         mlog(ML_SOCKET, "[sc %p refs %d sock %p node %u page %p "       \
 99              "pg_off %zu] " fmt, __sc,                                  \
100              atomic_read(&__sc->sc_kref.refcount), __sc->sc_sock,       \
101             __sc->sc_node->nd_num, __sc->sc_page, __sc->sc_page_off ,   \
102             ##args);                                                    \
103 } while (0)
104 
105 static DEFINE_RWLOCK(o2net_handler_lock);
106 static struct rb_root o2net_handler_tree = RB_ROOT;
107 
108 static struct o2net_node o2net_nodes[O2NM_MAX_NODES];
109 
110 /* XXX someday we'll need better accounting */
111 static struct socket *o2net_listen_sock;
112 
113 /*
114  * listen work is only queued by the listening socket callbacks on the
115  * o2net_wq.  teardown detaches the callbacks before destroying the workqueue.
116  * quorum work is queued as sock containers are shutdown.. stop_listening
117  * tears down all the node's sock containers, preventing future shutdowns
118  * and queued quroum work, before canceling delayed quorum work and
119  * destroying the work queue.
120  */
121 static struct workqueue_struct *o2net_wq;
122 static struct work_struct o2net_listen_work;
123 
124 static struct o2hb_callback_func o2net_hb_up, o2net_hb_down;
125 #define O2NET_HB_PRI 0x1
126 
127 static struct o2net_handshake *o2net_hand;
128 static struct o2net_msg *o2net_keep_req, *o2net_keep_resp;
129 
130 static int o2net_sys_err_translations[O2NET_ERR_MAX] =
131                 {[O2NET_ERR_NONE]       = 0,
132                  [O2NET_ERR_NO_HNDLR]   = -ENOPROTOOPT,
133                  [O2NET_ERR_OVERFLOW]   = -EOVERFLOW,
134                  [O2NET_ERR_DIED]       = -EHOSTDOWN,};
135 
136 /* can't quite avoid *all* internal declarations :/ */
137 static void o2net_sc_connect_completed(struct work_struct *work);
138 static void o2net_rx_until_empty(struct work_struct *work);
139 static void o2net_shutdown_sc(struct work_struct *work);
140 static void o2net_listen_data_ready(struct sock *sk);
141 static void o2net_sc_send_keep_req(struct work_struct *work);
142 static void o2net_idle_timer(unsigned long data);
143 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc);
144 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc);
145 
146 #ifdef CONFIG_DEBUG_FS
147 static void o2net_init_nst(struct o2net_send_tracking *nst, u32 msgtype,
148                            u32 msgkey, struct task_struct *task, u8 node)
149 {
150         INIT_LIST_HEAD(&nst->st_net_debug_item);
151         nst->st_task = task;
152         nst->st_msg_type = msgtype;
153         nst->st_msg_key = msgkey;
154         nst->st_node = node;
155 }
156 
157 static inline void o2net_set_nst_sock_time(struct o2net_send_tracking *nst)
158 {
159         nst->st_sock_time = ktime_get();
160 }
161 
162 static inline void o2net_set_nst_send_time(struct o2net_send_tracking *nst)
163 {
164         nst->st_send_time = ktime_get();
165 }
166 
167 static inline void o2net_set_nst_status_time(struct o2net_send_tracking *nst)
168 {
169         nst->st_status_time = ktime_get();
170 }
171 
172 static inline void o2net_set_nst_sock_container(struct o2net_send_tracking *nst,
173                                                 struct o2net_sock_container *sc)
174 {
175         nst->st_sc = sc;
176 }
177 
178 static inline void o2net_set_nst_msg_id(struct o2net_send_tracking *nst,
179                                         u32 msg_id)
180 {
181         nst->st_id = msg_id;
182 }
183 
184 static inline void o2net_set_sock_timer(struct o2net_sock_container *sc)
185 {
186         sc->sc_tv_timer = ktime_get();
187 }
188 
189 static inline void o2net_set_data_ready_time(struct o2net_sock_container *sc)
190 {
191         sc->sc_tv_data_ready = ktime_get();
192 }
193 
194 static inline void o2net_set_advance_start_time(struct o2net_sock_container *sc)
195 {
196         sc->sc_tv_advance_start = ktime_get();
197 }
198 
199 static inline void o2net_set_advance_stop_time(struct o2net_sock_container *sc)
200 {
201         sc->sc_tv_advance_stop = ktime_get();
202 }
203 
204 static inline void o2net_set_func_start_time(struct o2net_sock_container *sc)
205 {
206         sc->sc_tv_func_start = ktime_get();
207 }
208 
209 static inline void o2net_set_func_stop_time(struct o2net_sock_container *sc)
210 {
211         sc->sc_tv_func_stop = ktime_get();
212 }
213 
214 #else  /* CONFIG_DEBUG_FS */
215 # define o2net_init_nst(a, b, c, d, e)
216 # define o2net_set_nst_sock_time(a)
217 # define o2net_set_nst_send_time(a)
218 # define o2net_set_nst_status_time(a)
219 # define o2net_set_nst_sock_container(a, b)
220 # define o2net_set_nst_msg_id(a, b)
221 # define o2net_set_sock_timer(a)
222 # define o2net_set_data_ready_time(a)
223 # define o2net_set_advance_start_time(a)
224 # define o2net_set_advance_stop_time(a)
225 # define o2net_set_func_start_time(a)
226 # define o2net_set_func_stop_time(a)
227 #endif /* CONFIG_DEBUG_FS */
228 
229 #ifdef CONFIG_OCFS2_FS_STATS
230 static ktime_t o2net_get_func_run_time(struct o2net_sock_container *sc)
231 {
232         return ktime_sub(sc->sc_tv_func_stop, sc->sc_tv_func_start);
233 }
234 
235 static void o2net_update_send_stats(struct o2net_send_tracking *nst,
236                                     struct o2net_sock_container *sc)
237 {
238         sc->sc_tv_status_total = ktime_add(sc->sc_tv_status_total,
239                                            ktime_sub(ktime_get(),
240                                                      nst->st_status_time));
241         sc->sc_tv_send_total = ktime_add(sc->sc_tv_send_total,
242                                          ktime_sub(nst->st_status_time,
243                                                    nst->st_send_time));
244         sc->sc_tv_acquiry_total = ktime_add(sc->sc_tv_acquiry_total,
245                                             ktime_sub(nst->st_send_time,
246                                                       nst->st_sock_time));
247         sc->sc_send_count++;
248 }
249 
250 static void o2net_update_recv_stats(struct o2net_sock_container *sc)
251 {
252         sc->sc_tv_process_total = ktime_add(sc->sc_tv_process_total,
253                                             o2net_get_func_run_time(sc));
254         sc->sc_recv_count++;
255 }
256 
257 #else
258 
259 # define o2net_update_send_stats(a, b)
260 
261 # define o2net_update_recv_stats(sc)
262 
263 #endif /* CONFIG_OCFS2_FS_STATS */
264 
265 static inline unsigned int o2net_reconnect_delay(void)
266 {
267         return o2nm_single_cluster->cl_reconnect_delay_ms;
268 }
269 
270 static inline unsigned int o2net_keepalive_delay(void)
271 {
272         return o2nm_single_cluster->cl_keepalive_delay_ms;
273 }
274 
275 static inline unsigned int o2net_idle_timeout(void)
276 {
277         return o2nm_single_cluster->cl_idle_timeout_ms;
278 }
279 
280 static inline int o2net_sys_err_to_errno(enum o2net_system_error err)
281 {
282         int trans;
283         BUG_ON(err >= O2NET_ERR_MAX);
284         trans = o2net_sys_err_translations[err];
285 
286         /* Just in case we mess up the translation table above */
287         BUG_ON(err != O2NET_ERR_NONE && trans == 0);
288         return trans;
289 }
290 
291 static struct o2net_node * o2net_nn_from_num(u8 node_num)
292 {
293         BUG_ON(node_num >= ARRAY_SIZE(o2net_nodes));
294         return &o2net_nodes[node_num];
295 }
296 
297 static u8 o2net_num_from_nn(struct o2net_node *nn)
298 {
299         BUG_ON(nn == NULL);
300         return nn - o2net_nodes;
301 }
302 
303 /* ------------------------------------------------------------ */
304 
305 static int o2net_prep_nsw(struct o2net_node *nn, struct o2net_status_wait *nsw)
306 {
307         int ret;
308 
309         spin_lock(&nn->nn_lock);
310         ret = idr_alloc(&nn->nn_status_idr, nsw, 0, 0, GFP_ATOMIC);
311         if (ret >= 0) {
312                 nsw->ns_id = ret;
313                 list_add_tail(&nsw->ns_node_item, &nn->nn_status_list);
314         }
315         spin_unlock(&nn->nn_lock);
316         if (ret < 0)
317                 return ret;
318 
319         init_waitqueue_head(&nsw->ns_wq);
320         nsw->ns_sys_status = O2NET_ERR_NONE;
321         nsw->ns_status = 0;
322         return 0;
323 }
324 
325 static void o2net_complete_nsw_locked(struct o2net_node *nn,
326                                       struct o2net_status_wait *nsw,
327                                       enum o2net_system_error sys_status,
328                                       s32 status)
329 {
330         assert_spin_locked(&nn->nn_lock);
331 
332         if (!list_empty(&nsw->ns_node_item)) {
333                 list_del_init(&nsw->ns_node_item);
334                 nsw->ns_sys_status = sys_status;
335                 nsw->ns_status = status;
336                 idr_remove(&nn->nn_status_idr, nsw->ns_id);
337                 wake_up(&nsw->ns_wq);
338         }
339 }
340 
341 static void o2net_complete_nsw(struct o2net_node *nn,
342                                struct o2net_status_wait *nsw,
343                                u64 id, enum o2net_system_error sys_status,
344                                s32 status)
345 {
346         spin_lock(&nn->nn_lock);
347         if (nsw == NULL) {
348                 if (id > INT_MAX)
349                         goto out;
350 
351                 nsw = idr_find(&nn->nn_status_idr, id);
352                 if (nsw == NULL)
353                         goto out;
354         }
355 
356         o2net_complete_nsw_locked(nn, nsw, sys_status, status);
357 
358 out:
359         spin_unlock(&nn->nn_lock);
360         return;
361 }
362 
363 static void o2net_complete_nodes_nsw(struct o2net_node *nn)
364 {
365         struct o2net_status_wait *nsw, *tmp;
366         unsigned int num_kills = 0;
367 
368         assert_spin_locked(&nn->nn_lock);
369 
370         list_for_each_entry_safe(nsw, tmp, &nn->nn_status_list, ns_node_item) {
371                 o2net_complete_nsw_locked(nn, nsw, O2NET_ERR_DIED, 0);
372                 num_kills++;
373         }
374 
375         mlog(0, "completed %d messages for node %u\n", num_kills,
376              o2net_num_from_nn(nn));
377 }
378 
379 static int o2net_nsw_completed(struct o2net_node *nn,
380                                struct o2net_status_wait *nsw)
381 {
382         int completed;
383         spin_lock(&nn->nn_lock);
384         completed = list_empty(&nsw->ns_node_item);
385         spin_unlock(&nn->nn_lock);
386         return completed;
387 }
388 
389 /* ------------------------------------------------------------ */
390 
391 static void sc_kref_release(struct kref *kref)
392 {
393         struct o2net_sock_container *sc = container_of(kref,
394                                         struct o2net_sock_container, sc_kref);
395         BUG_ON(timer_pending(&sc->sc_idle_timeout));
396 
397         sclog(sc, "releasing\n");
398 
399         if (sc->sc_sock) {
400                 sock_release(sc->sc_sock);
401                 sc->sc_sock = NULL;
402         }
403 
404         o2nm_undepend_item(&sc->sc_node->nd_item);
405         o2nm_node_put(sc->sc_node);
406         sc->sc_node = NULL;
407 
408         o2net_debug_del_sc(sc);
409 
410         if (sc->sc_page)
411                 __free_page(sc->sc_page);
412         kfree(sc);
413 }
414 
415 static void sc_put(struct o2net_sock_container *sc)
416 {
417         sclog(sc, "put\n");
418         kref_put(&sc->sc_kref, sc_kref_release);
419 }
420 static void sc_get(struct o2net_sock_container *sc)
421 {
422         sclog(sc, "get\n");
423         kref_get(&sc->sc_kref);
424 }
425 static struct o2net_sock_container *sc_alloc(struct o2nm_node *node)
426 {
427         struct o2net_sock_container *sc, *ret = NULL;
428         struct page *page = NULL;
429         int status = 0;
430 
431         page = alloc_page(GFP_NOFS);
432         sc = kzalloc(sizeof(*sc), GFP_NOFS);
433         if (sc == NULL || page == NULL)
434                 goto out;
435 
436         kref_init(&sc->sc_kref);
437         o2nm_node_get(node);
438         sc->sc_node = node;
439 
440         /* pin the node item of the remote node */
441         status = o2nm_depend_item(&node->nd_item);
442         if (status) {
443                 mlog_errno(status);
444                 o2nm_node_put(node);
445                 goto out;
446         }
447         INIT_WORK(&sc->sc_connect_work, o2net_sc_connect_completed);
448         INIT_WORK(&sc->sc_rx_work, o2net_rx_until_empty);
449         INIT_WORK(&sc->sc_shutdown_work, o2net_shutdown_sc);
450         INIT_DELAYED_WORK(&sc->sc_keepalive_work, o2net_sc_send_keep_req);
451 
452         init_timer(&sc->sc_idle_timeout);
453         sc->sc_idle_timeout.function = o2net_idle_timer;
454         sc->sc_idle_timeout.data = (unsigned long)sc;
455 
456         sclog(sc, "alloced\n");
457 
458         ret = sc;
459         sc->sc_page = page;
460         o2net_debug_add_sc(sc);
461         sc = NULL;
462         page = NULL;
463 
464 out:
465         if (page)
466                 __free_page(page);
467         kfree(sc);
468 
469         return ret;
470 }
471 
472 /* ------------------------------------------------------------ */
473 
474 static void o2net_sc_queue_work(struct o2net_sock_container *sc,
475                                 struct work_struct *work)
476 {
477         sc_get(sc);
478         if (!queue_work(o2net_wq, work))
479                 sc_put(sc);
480 }
481 static void o2net_sc_queue_delayed_work(struct o2net_sock_container *sc,
482                                         struct delayed_work *work,
483                                         int delay)
484 {
485         sc_get(sc);
486         if (!queue_delayed_work(o2net_wq, work, delay))
487                 sc_put(sc);
488 }
489 static void o2net_sc_cancel_delayed_work(struct o2net_sock_container *sc,
490                                          struct delayed_work *work)
491 {
492         if (cancel_delayed_work(work))
493                 sc_put(sc);
494 }
495 
496 static atomic_t o2net_connected_peers = ATOMIC_INIT(0);
497 
498 int o2net_num_connected_peers(void)
499 {
500         return atomic_read(&o2net_connected_peers);
501 }
502 
503 static void o2net_set_nn_state(struct o2net_node *nn,
504                                struct o2net_sock_container *sc,
505                                unsigned valid, int err)
506 {
507         int was_valid = nn->nn_sc_valid;
508         int was_err = nn->nn_persistent_error;
509         struct o2net_sock_container *old_sc = nn->nn_sc;
510 
511         assert_spin_locked(&nn->nn_lock);
512 
513         if (old_sc && !sc)
514                 atomic_dec(&o2net_connected_peers);
515         else if (!old_sc && sc)
516                 atomic_inc(&o2net_connected_peers);
517 
518         /* the node num comparison and single connect/accept path should stop
519          * an non-null sc from being overwritten with another */
520         BUG_ON(sc && nn->nn_sc && nn->nn_sc != sc);
521         mlog_bug_on_msg(err && valid, "err %d valid %u\n", err, valid);
522         mlog_bug_on_msg(valid && !sc, "valid %u sc %p\n", valid, sc);
523 
524         if (was_valid && !valid && err == 0)
525                 err = -ENOTCONN;
526 
527         mlog(ML_CONN, "node %u sc: %p -> %p, valid %u -> %u, err %d -> %d\n",
528              o2net_num_from_nn(nn), nn->nn_sc, sc, nn->nn_sc_valid, valid,
529              nn->nn_persistent_error, err);
530 
531         nn->nn_sc = sc;
532         nn->nn_sc_valid = valid ? 1 : 0;
533         nn->nn_persistent_error = err;
534 
535         /* mirrors o2net_tx_can_proceed() */
536         if (nn->nn_persistent_error || nn->nn_sc_valid)
537                 wake_up(&nn->nn_sc_wq);
538 
539         if (!was_err && nn->nn_persistent_error) {
540                 o2quo_conn_err(o2net_num_from_nn(nn));
541                 queue_delayed_work(o2net_wq, &nn->nn_still_up,
542                                    msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
543         }
544 
545         if (was_valid && !valid) {
546                 if (old_sc)
547                         printk(KERN_NOTICE "o2net: No longer connected to "
548                                 SC_NODEF_FMT "\n", SC_NODEF_ARGS(old_sc));
549                 o2net_complete_nodes_nsw(nn);
550         }
551 
552         if (!was_valid && valid) {
553                 o2quo_conn_up(o2net_num_from_nn(nn));
554                 cancel_delayed_work(&nn->nn_connect_expired);
555                 printk(KERN_NOTICE "o2net: %s " SC_NODEF_FMT "\n",
556                        o2nm_this_node() > sc->sc_node->nd_num ?
557                        "Connected to" : "Accepted connection from",
558                        SC_NODEF_ARGS(sc));
559         }
560 
561         /* trigger the connecting worker func as long as we're not valid,
562          * it will back off if it shouldn't connect.  This can be called
563          * from node config teardown and so needs to be careful about
564          * the work queue actually being up. */
565         if (!valid && o2net_wq) {
566                 unsigned long delay;
567                 /* delay if we're within a RECONNECT_DELAY of the
568                  * last attempt */
569                 delay = (nn->nn_last_connect_attempt +
570                          msecs_to_jiffies(o2net_reconnect_delay()))
571                         - jiffies;
572                 if (delay > msecs_to_jiffies(o2net_reconnect_delay()))
573                         delay = 0;
574                 mlog(ML_CONN, "queueing conn attempt in %lu jiffies\n", delay);
575                 queue_delayed_work(o2net_wq, &nn->nn_connect_work, delay);
576 
577                 /*
578                  * Delay the expired work after idle timeout.
579                  *
580                  * We might have lots of failed connection attempts that run
581                  * through here but we only cancel the connect_expired work when
582                  * a connection attempt succeeds.  So only the first enqueue of
583                  * the connect_expired work will do anything.  The rest will see
584                  * that it's already queued and do nothing.
585                  */
586                 delay += msecs_to_jiffies(o2net_idle_timeout());
587                 queue_delayed_work(o2net_wq, &nn->nn_connect_expired, delay);
588         }
589 
590         /* keep track of the nn's sc ref for the caller */
591         if ((old_sc == NULL) && sc)
592                 sc_get(sc);
593         if (old_sc && (old_sc != sc)) {
594                 o2net_sc_queue_work(old_sc, &old_sc->sc_shutdown_work);
595                 sc_put(old_sc);
596         }
597 }
598 
599 /* see o2net_register_callbacks() */
600 static void o2net_data_ready(struct sock *sk)
601 {
602         void (*ready)(struct sock *sk);
603 
604         read_lock(&sk->sk_callback_lock);
605         if (sk->sk_user_data) {
606                 struct o2net_sock_container *sc = sk->sk_user_data;
607                 sclog(sc, "data_ready hit\n");
608                 o2net_set_data_ready_time(sc);
609                 o2net_sc_queue_work(sc, &sc->sc_rx_work);
610                 ready = sc->sc_data_ready;
611         } else {
612                 ready = sk->sk_data_ready;
613         }
614         read_unlock(&sk->sk_callback_lock);
615 
616         ready(sk);
617 }
618 
619 /* see o2net_register_callbacks() */
620 static void o2net_state_change(struct sock *sk)
621 {
622         void (*state_change)(struct sock *sk);
623         struct o2net_sock_container *sc;
624 
625         read_lock(&sk->sk_callback_lock);
626         sc = sk->sk_user_data;
627         if (sc == NULL) {
628                 state_change = sk->sk_state_change;
629                 goto out;
630         }
631 
632         sclog(sc, "state_change to %d\n", sk->sk_state);
633 
634         state_change = sc->sc_state_change;
635 
636         switch(sk->sk_state) {
637         /* ignore connecting sockets as they make progress */
638         case TCP_SYN_SENT:
639         case TCP_SYN_RECV:
640                 break;
641         case TCP_ESTABLISHED:
642                 o2net_sc_queue_work(sc, &sc->sc_connect_work);
643                 break;
644         default:
645                 printk(KERN_INFO "o2net: Connection to " SC_NODEF_FMT
646                         " shutdown, state %d\n",
647                         SC_NODEF_ARGS(sc), sk->sk_state);
648                 o2net_sc_queue_work(sc, &sc->sc_shutdown_work);
649                 break;
650         }
651 out:
652         read_unlock(&sk->sk_callback_lock);
653         state_change(sk);
654 }
655 
656 /*
657  * we register callbacks so we can queue work on events before calling
658  * the original callbacks.  our callbacks our careful to test user_data
659  * to discover when they've reaced with o2net_unregister_callbacks().
660  */
661 static void o2net_register_callbacks(struct sock *sk,
662                                      struct o2net_sock_container *sc)
663 {
664         write_lock_bh(&sk->sk_callback_lock);
665 
666         /* accepted sockets inherit the old listen socket data ready */
667         if (sk->sk_data_ready == o2net_listen_data_ready) {
668                 sk->sk_data_ready = sk->sk_user_data;
669                 sk->sk_user_data = NULL;
670         }
671 
672         BUG_ON(sk->sk_user_data != NULL);
673         sk->sk_user_data = sc;
674         sc_get(sc);
675 
676         sc->sc_data_ready = sk->sk_data_ready;
677         sc->sc_state_change = sk->sk_state_change;
678         sk->sk_data_ready = o2net_data_ready;
679         sk->sk_state_change = o2net_state_change;
680 
681         mutex_init(&sc->sc_send_lock);
682 
683         write_unlock_bh(&sk->sk_callback_lock);
684 }
685 
686 static int o2net_unregister_callbacks(struct sock *sk,
687                                    struct o2net_sock_container *sc)
688 {
689         int ret = 0;
690 
691         write_lock_bh(&sk->sk_callback_lock);
692         if (sk->sk_user_data == sc) {
693                 ret = 1;
694                 sk->sk_user_data = NULL;
695                 sk->sk_data_ready = sc->sc_data_ready;
696                 sk->sk_state_change = sc->sc_state_change;
697         }
698         write_unlock_bh(&sk->sk_callback_lock);
699 
700         return ret;
701 }
702 
703 /*
704  * this is a little helper that is called by callers who have seen a problem
705  * with an sc and want to detach it from the nn if someone already hasn't beat
706  * them to it.  if an error is given then the shutdown will be persistent
707  * and pending transmits will be canceled.
708  */
709 static void o2net_ensure_shutdown(struct o2net_node *nn,
710                                    struct o2net_sock_container *sc,
711                                    int err)
712 {
713         spin_lock(&nn->nn_lock);
714         if (nn->nn_sc == sc)
715                 o2net_set_nn_state(nn, NULL, 0, err);
716         spin_unlock(&nn->nn_lock);
717 }
718 
719 /*
720  * This work queue function performs the blocking parts of socket shutdown.  A
721  * few paths lead here.  set_nn_state will trigger this callback if it sees an
722  * sc detached from the nn.  state_change will also trigger this callback
723  * directly when it sees errors.  In that case we need to call set_nn_state
724  * ourselves as state_change couldn't get the nn_lock and call set_nn_state
725  * itself.
726  */
727 static void o2net_shutdown_sc(struct work_struct *work)
728 {
729         struct o2net_sock_container *sc =
730                 container_of(work, struct o2net_sock_container,
731                              sc_shutdown_work);
732         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
733 
734         sclog(sc, "shutting down\n");
735 
736         /* drop the callbacks ref and call shutdown only once */
737         if (o2net_unregister_callbacks(sc->sc_sock->sk, sc)) {
738                 /* we shouldn't flush as we're in the thread, the
739                  * races with pending sc work structs are harmless */
740                 del_timer_sync(&sc->sc_idle_timeout);
741                 o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
742                 sc_put(sc);
743                 kernel_sock_shutdown(sc->sc_sock, SHUT_RDWR);
744         }
745 
746         /* not fatal so failed connects before the other guy has our
747          * heartbeat can be retried */
748         o2net_ensure_shutdown(nn, sc, 0);
749         sc_put(sc);
750 }
751 
752 /* ------------------------------------------------------------ */
753 
754 static int o2net_handler_cmp(struct o2net_msg_handler *nmh, u32 msg_type,
755                              u32 key)
756 {
757         int ret = memcmp(&nmh->nh_key, &key, sizeof(key));
758 
759         if (ret == 0)
760                 ret = memcmp(&nmh->nh_msg_type, &msg_type, sizeof(msg_type));
761 
762         return ret;
763 }
764 
765 static struct o2net_msg_handler *
766 o2net_handler_tree_lookup(u32 msg_type, u32 key, struct rb_node ***ret_p,
767                           struct rb_node **ret_parent)
768 {
769         struct rb_node **p = &o2net_handler_tree.rb_node;
770         struct rb_node *parent = NULL;
771         struct o2net_msg_handler *nmh, *ret = NULL;
772         int cmp;
773 
774         while (*p) {
775                 parent = *p;
776                 nmh = rb_entry(parent, struct o2net_msg_handler, nh_node);
777                 cmp = o2net_handler_cmp(nmh, msg_type, key);
778 
779                 if (cmp < 0)
780                         p = &(*p)->rb_left;
781                 else if (cmp > 0)
782                         p = &(*p)->rb_right;
783                 else {
784                         ret = nmh;
785                         break;
786                 }
787         }
788 
789         if (ret_p != NULL)
790                 *ret_p = p;
791         if (ret_parent != NULL)
792                 *ret_parent = parent;
793 
794         return ret;
795 }
796 
797 static void o2net_handler_kref_release(struct kref *kref)
798 {
799         struct o2net_msg_handler *nmh;
800         nmh = container_of(kref, struct o2net_msg_handler, nh_kref);
801 
802         kfree(nmh);
803 }
804 
805 static void o2net_handler_put(struct o2net_msg_handler *nmh)
806 {
807         kref_put(&nmh->nh_kref, o2net_handler_kref_release);
808 }
809 
810 /* max_len is protection for the handler func.  incoming messages won't
811  * be given to the handler if their payload is longer than the max. */
812 int o2net_register_handler(u32 msg_type, u32 key, u32 max_len,
813                            o2net_msg_handler_func *func, void *data,
814                            o2net_post_msg_handler_func *post_func,
815                            struct list_head *unreg_list)
816 {
817         struct o2net_msg_handler *nmh = NULL;
818         struct rb_node **p, *parent;
819         int ret = 0;
820 
821         if (max_len > O2NET_MAX_PAYLOAD_BYTES) {
822                 mlog(0, "max_len for message handler out of range: %u\n",
823                         max_len);
824                 ret = -EINVAL;
825                 goto out;
826         }
827 
828         if (!msg_type) {
829                 mlog(0, "no message type provided: %u, %p\n", msg_type, func);
830                 ret = -EINVAL;
831                 goto out;
832 
833         }
834         if (!func) {
835                 mlog(0, "no message handler provided: %u, %p\n",
836                        msg_type, func);
837                 ret = -EINVAL;
838                 goto out;
839         }
840 
841         nmh = kzalloc(sizeof(struct o2net_msg_handler), GFP_NOFS);
842         if (nmh == NULL) {
843                 ret = -ENOMEM;
844                 goto out;
845         }
846 
847         nmh->nh_func = func;
848         nmh->nh_func_data = data;
849         nmh->nh_post_func = post_func;
850         nmh->nh_msg_type = msg_type;
851         nmh->nh_max_len = max_len;
852         nmh->nh_key = key;
853         /* the tree and list get this ref.. they're both removed in
854          * unregister when this ref is dropped */
855         kref_init(&nmh->nh_kref);
856         INIT_LIST_HEAD(&nmh->nh_unregister_item);
857 
858         write_lock(&o2net_handler_lock);
859         if (o2net_handler_tree_lookup(msg_type, key, &p, &parent))
860                 ret = -EEXIST;
861         else {
862                 rb_link_node(&nmh->nh_node, parent, p);
863                 rb_insert_color(&nmh->nh_node, &o2net_handler_tree);
864                 list_add_tail(&nmh->nh_unregister_item, unreg_list);
865 
866                 mlog(ML_TCP, "registered handler func %p type %u key %08x\n",
867                      func, msg_type, key);
868                 /* we've had some trouble with handlers seemingly vanishing. */
869                 mlog_bug_on_msg(o2net_handler_tree_lookup(msg_type, key, &p,
870                                                           &parent) == NULL,
871                                 "couldn't find handler we *just* registered "
872                                 "for type %u key %08x\n", msg_type, key);
873         }
874         write_unlock(&o2net_handler_lock);
875         if (ret)
876                 goto out;
877 
878 out:
879         if (ret)
880                 kfree(nmh);
881 
882         return ret;
883 }
884 EXPORT_SYMBOL_GPL(o2net_register_handler);
885 
886 void o2net_unregister_handler_list(struct list_head *list)
887 {
888         struct o2net_msg_handler *nmh, *n;
889 
890         write_lock(&o2net_handler_lock);
891         list_for_each_entry_safe(nmh, n, list, nh_unregister_item) {
892                 mlog(ML_TCP, "unregistering handler func %p type %u key %08x\n",
893                      nmh->nh_func, nmh->nh_msg_type, nmh->nh_key);
894                 rb_erase(&nmh->nh_node, &o2net_handler_tree);
895                 list_del_init(&nmh->nh_unregister_item);
896                 kref_put(&nmh->nh_kref, o2net_handler_kref_release);
897         }
898         write_unlock(&o2net_handler_lock);
899 }
900 EXPORT_SYMBOL_GPL(o2net_unregister_handler_list);
901 
902 static struct o2net_msg_handler *o2net_handler_get(u32 msg_type, u32 key)
903 {
904         struct o2net_msg_handler *nmh;
905 
906         read_lock(&o2net_handler_lock);
907         nmh = o2net_handler_tree_lookup(msg_type, key, NULL, NULL);
908         if (nmh)
909                 kref_get(&nmh->nh_kref);
910         read_unlock(&o2net_handler_lock);
911 
912         return nmh;
913 }
914 
915 /* ------------------------------------------------------------ */
916 
917 static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
918 {
919         struct kvec vec = { .iov_len = len, .iov_base = data, };
920         struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
921         return kernel_recvmsg(sock, &msg, &vec, 1, len, msg.msg_flags);
922 }
923 
924 static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
925                               size_t veclen, size_t total)
926 {
927         int ret;
928         struct msghdr msg = {.msg_flags = 0,};
929 
930         if (sock == NULL) {
931                 ret = -EINVAL;
932                 goto out;
933         }
934 
935         ret = kernel_sendmsg(sock, &msg, vec, veclen, total);
936         if (likely(ret == total))
937                 return 0;
938         mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret, total);
939         if (ret >= 0)
940                 ret = -EPIPE; /* should be smarter, I bet */
941 out:
942         mlog(0, "returning error: %d\n", ret);
943         return ret;
944 }
945 
946 static void o2net_sendpage(struct o2net_sock_container *sc,
947                            void *kmalloced_virt,
948                            size_t size)
949 {
950         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
951         ssize_t ret;
952 
953         while (1) {
954                 mutex_lock(&sc->sc_send_lock);
955                 ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
956                                                  virt_to_page(kmalloced_virt),
957                                                  (long)kmalloced_virt & ~PAGE_MASK,
958                                                  size, MSG_DONTWAIT);
959                 mutex_unlock(&sc->sc_send_lock);
960                 if (ret == size)
961                         break;
962                 if (ret == (ssize_t)-EAGAIN) {
963                         mlog(0, "sendpage of size %zu to " SC_NODEF_FMT
964                              " returned EAGAIN\n", size, SC_NODEF_ARGS(sc));
965                         cond_resched();
966                         continue;
967                 }
968                 mlog(ML_ERROR, "sendpage of size %zu to " SC_NODEF_FMT
969                      " failed with %zd\n", size, SC_NODEF_ARGS(sc), ret);
970                 o2net_ensure_shutdown(nn, sc, 0);
971                 break;
972         }
973 }
974 
975 static void o2net_init_msg(struct o2net_msg *msg, u16 data_len, u16 msg_type, u32 key)
976 {
977         memset(msg, 0, sizeof(struct o2net_msg));
978         msg->magic = cpu_to_be16(O2NET_MSG_MAGIC);
979         msg->data_len = cpu_to_be16(data_len);
980         msg->msg_type = cpu_to_be16(msg_type);
981         msg->sys_status = cpu_to_be32(O2NET_ERR_NONE);
982         msg->status = 0;
983         msg->key = cpu_to_be32(key);
984 }
985 
986 static int o2net_tx_can_proceed(struct o2net_node *nn,
987                                 struct o2net_sock_container **sc_ret,
988                                 int *error)
989 {
990         int ret = 0;
991 
992         spin_lock(&nn->nn_lock);
993         if (nn->nn_persistent_error) {
994                 ret = 1;
995                 *sc_ret = NULL;
996                 *error = nn->nn_persistent_error;
997         } else if (nn->nn_sc_valid) {
998                 kref_get(&nn->nn_sc->sc_kref);
999 
1000                 ret = 1;
1001                 *sc_ret = nn->nn_sc;
1002                 *error = 0;
1003         }
1004         spin_unlock(&nn->nn_lock);
1005 
1006         return ret;
1007 }
1008 
1009 /* Get a map of all nodes to which this node is currently connected to */
1010 void o2net_fill_node_map(unsigned long *map, unsigned bytes)
1011 {
1012         struct o2net_sock_container *sc;
1013         int node, ret;
1014 
1015         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1016 
1017         memset(map, 0, bytes);
1018         for (node = 0; node < O2NM_MAX_NODES; ++node) {
1019                 o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret);
1020                 if (!ret) {
1021                         set_bit(node, map);
1022                         sc_put(sc);
1023                 }
1024         }
1025 }
1026 EXPORT_SYMBOL_GPL(o2net_fill_node_map);
1027 
1028 int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
1029                            size_t caller_veclen, u8 target_node, int *status)
1030 {
1031         int ret = 0;
1032         struct o2net_msg *msg = NULL;
1033         size_t veclen, caller_bytes = 0;
1034         struct kvec *vec = NULL;
1035         struct o2net_sock_container *sc = NULL;
1036         struct o2net_node *nn = o2net_nn_from_num(target_node);
1037         struct o2net_status_wait nsw = {
1038                 .ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
1039         };
1040         struct o2net_send_tracking nst;
1041 
1042         o2net_init_nst(&nst, msg_type, key, current, target_node);
1043 
1044         if (o2net_wq == NULL) {
1045                 mlog(0, "attempt to tx without o2netd running\n");
1046                 ret = -ESRCH;
1047                 goto out;
1048         }
1049 
1050         if (caller_veclen == 0) {
1051                 mlog(0, "bad kvec array length\n");
1052                 ret = -EINVAL;
1053                 goto out;
1054         }
1055 
1056         caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
1057         if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
1058                 mlog(0, "total payload len %zu too large\n", caller_bytes);
1059                 ret = -EINVAL;
1060                 goto out;
1061         }
1062 
1063         if (target_node == o2nm_this_node()) {
1064                 ret = -ELOOP;
1065                 goto out;
1066         }
1067 
1068         o2net_debug_add_nst(&nst);
1069 
1070         o2net_set_nst_sock_time(&nst);
1071 
1072         wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
1073         if (ret)
1074                 goto out;
1075 
1076         o2net_set_nst_sock_container(&nst, sc);
1077 
1078         veclen = caller_veclen + 1;
1079         vec = kmalloc(sizeof(struct kvec) * veclen, GFP_ATOMIC);
1080         if (vec == NULL) {
1081                 mlog(0, "failed to %zu element kvec!\n", veclen);
1082                 ret = -ENOMEM;
1083                 goto out;
1084         }
1085 
1086         msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
1087         if (!msg) {
1088                 mlog(0, "failed to allocate a o2net_msg!\n");
1089                 ret = -ENOMEM;
1090                 goto out;
1091         }
1092 
1093         o2net_init_msg(msg, caller_bytes, msg_type, key);
1094 
1095         vec[0].iov_len = sizeof(struct o2net_msg);
1096         vec[0].iov_base = msg;
1097         memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
1098 
1099         ret = o2net_prep_nsw(nn, &nsw);
1100         if (ret)
1101                 goto out;
1102 
1103         msg->msg_num = cpu_to_be32(nsw.ns_id);
1104         o2net_set_nst_msg_id(&nst, nsw.ns_id);
1105 
1106         o2net_set_nst_send_time(&nst);
1107 
1108         /* finally, convert the message header to network byte-order
1109          * and send */
1110         mutex_lock(&sc->sc_send_lock);
1111         ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
1112                                  sizeof(struct o2net_msg) + caller_bytes);
1113         mutex_unlock(&sc->sc_send_lock);
1114         msglog(msg, "sending returned %d\n", ret);
1115         if (ret < 0) {
1116                 mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
1117                 goto out;
1118         }
1119 
1120         /* wait on other node's handler */
1121         o2net_set_nst_status_time(&nst);
1122         wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
1123 
1124         o2net_update_send_stats(&nst, sc);
1125 
1126         /* Note that we avoid overwriting the callers status return
1127          * variable if a system error was reported on the other
1128          * side. Callers beware. */
1129         ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
1130         if (status && !ret)
1131                 *status = nsw.ns_status;
1132 
1133         mlog(0, "woken, returning system status %d, user status %d\n",
1134              ret, nsw.ns_status);
1135 out:
1136         o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
1137         if (sc)
1138                 sc_put(sc);
1139         kfree(vec);
1140         kfree(msg);
1141         o2net_complete_nsw(nn, &nsw, 0, 0, 0);
1142         return ret;
1143 }
1144 EXPORT_SYMBOL_GPL(o2net_send_message_vec);
1145 
1146 int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
1147                        u8 target_node, int *status)
1148 {
1149         struct kvec vec = {
1150                 .iov_base = data,
1151                 .iov_len = len,
1152         };
1153         return o2net_send_message_vec(msg_type, key, &vec, 1,
1154                                       target_node, status);
1155 }
1156 EXPORT_SYMBOL_GPL(o2net_send_message);
1157 
1158 static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
1159                                    enum o2net_system_error syserr, int err)
1160 {
1161         struct kvec vec = {
1162                 .iov_base = hdr,
1163                 .iov_len = sizeof(struct o2net_msg),
1164         };
1165 
1166         BUG_ON(syserr >= O2NET_ERR_MAX);
1167 
1168         /* leave other fields intact from the incoming message, msg_num
1169          * in particular */
1170         hdr->sys_status = cpu_to_be32(syserr);
1171         hdr->status = cpu_to_be32(err);
1172         hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
1173         hdr->data_len = 0;
1174 
1175         msglog(hdr, "about to send status magic %d\n", err);
1176         /* hdr has been in host byteorder this whole time */
1177         return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
1178 }
1179 
1180 /* this returns -errno if the header was unknown or too large, etc.
1181  * after this is called the buffer us reused for the next message */
1182 static int o2net_process_message(struct o2net_sock_container *sc,
1183                                  struct o2net_msg *hdr)
1184 {
1185         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1186         int ret = 0, handler_status;
1187         enum  o2net_system_error syserr;
1188         struct o2net_msg_handler *nmh = NULL;
1189         void *ret_data = NULL;
1190 
1191         msglog(hdr, "processing message\n");
1192 
1193         o2net_sc_postpone_idle(sc);
1194 
1195         switch(be16_to_cpu(hdr->magic)) {
1196                 case O2NET_MSG_STATUS_MAGIC:
1197                         /* special type for returning message status */
1198                         o2net_complete_nsw(nn, NULL,
1199                                            be32_to_cpu(hdr->msg_num),
1200                                            be32_to_cpu(hdr->sys_status),
1201                                            be32_to_cpu(hdr->status));
1202                         goto out;
1203                 case O2NET_MSG_KEEP_REQ_MAGIC:
1204                         o2net_sendpage(sc, o2net_keep_resp,
1205                                        sizeof(*o2net_keep_resp));
1206                         goto out;
1207                 case O2NET_MSG_KEEP_RESP_MAGIC:
1208                         goto out;
1209                 case O2NET_MSG_MAGIC:
1210                         break;
1211                 default:
1212                         msglog(hdr, "bad magic\n");
1213                         ret = -EINVAL;
1214                         goto out;
1215                         break;
1216         }
1217 
1218         /* find a handler for it */
1219         handler_status = 0;
1220         nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
1221                                 be32_to_cpu(hdr->key));
1222         if (!nmh) {
1223                 mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
1224                      be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
1225                 syserr = O2NET_ERR_NO_HNDLR;
1226                 goto out_respond;
1227         }
1228 
1229         syserr = O2NET_ERR_NONE;
1230 
1231         if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
1232                 syserr = O2NET_ERR_OVERFLOW;
1233 
1234         if (syserr != O2NET_ERR_NONE)
1235                 goto out_respond;
1236 
1237         o2net_set_func_start_time(sc);
1238         sc->sc_msg_key = be32_to_cpu(hdr->key);
1239         sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
1240         handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
1241                                              be16_to_cpu(hdr->data_len),
1242                                         nmh->nh_func_data, &ret_data);
1243         o2net_set_func_stop_time(sc);
1244 
1245         o2net_update_recv_stats(sc);
1246 
1247 out_respond:
1248         /* this destroys the hdr, so don't use it after this */
1249         mutex_lock(&sc->sc_send_lock);
1250         ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
1251                                       handler_status);
1252         mutex_unlock(&sc->sc_send_lock);
1253         hdr = NULL;
1254         mlog(0, "sending handler status %d, syserr %d returned %d\n",
1255              handler_status, syserr, ret);
1256 
1257         if (nmh) {
1258                 BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
1259                 if (nmh->nh_post_func)
1260                         (nmh->nh_post_func)(handler_status, nmh->nh_func_data,
1261                                             ret_data);
1262         }
1263 
1264 out:
1265         if (nmh)
1266                 o2net_handler_put(nmh);
1267         return ret;
1268 }
1269 
1270 static int o2net_check_handshake(struct o2net_sock_container *sc)
1271 {
1272         struct o2net_handshake *hand = page_address(sc->sc_page);
1273         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1274 
1275         if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
1276                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
1277                        "protocol version %llu but %llu is required. "
1278                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1279                        (unsigned long long)be64_to_cpu(hand->protocol_version),
1280                        O2NET_PROTOCOL_VERSION);
1281 
1282                 /* don't bother reconnecting if its the wrong version. */
1283                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1284                 return -1;
1285         }
1286 
1287         /*
1288          * Ensure timeouts are consistent with other nodes, otherwise
1289          * we can end up with one node thinking that the other must be down,
1290          * but isn't. This can ultimately cause corruption.
1291          */
1292         if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
1293                                 o2net_idle_timeout()) {
1294                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
1295                        "idle timeout of %u ms, but we use %u ms locally. "
1296                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1297                        be32_to_cpu(hand->o2net_idle_timeout_ms),
1298                        o2net_idle_timeout());
1299                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1300                 return -1;
1301         }
1302 
1303         if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
1304                         o2net_keepalive_delay()) {
1305                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
1306                        "delay of %u ms, but we use %u ms locally. "
1307                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1308                        be32_to_cpu(hand->o2net_keepalive_delay_ms),
1309                        o2net_keepalive_delay());
1310                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1311                 return -1;
1312         }
1313 
1314         if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
1315                         O2HB_MAX_WRITE_TIMEOUT_MS) {
1316                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
1317                        "timeout of %u ms, but we use %u ms locally. "
1318                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1319                        be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
1320                        O2HB_MAX_WRITE_TIMEOUT_MS);
1321                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1322                 return -1;
1323         }
1324 
1325         sc->sc_handshake_ok = 1;
1326 
1327         spin_lock(&nn->nn_lock);
1328         /* set valid and queue the idle timers only if it hasn't been
1329          * shut down already */
1330         if (nn->nn_sc == sc) {
1331                 o2net_sc_reset_idle_timer(sc);
1332                 atomic_set(&nn->nn_timeout, 0);
1333                 o2net_set_nn_state(nn, sc, 1, 0);
1334         }
1335         spin_unlock(&nn->nn_lock);
1336 
1337         /* shift everything up as though it wasn't there */
1338         sc->sc_page_off -= sizeof(struct o2net_handshake);
1339         if (sc->sc_page_off)
1340                 memmove(hand, hand + 1, sc->sc_page_off);
1341 
1342         return 0;
1343 }
1344 
1345 /* this demuxes the queued rx bytes into header or payload bits and calls
1346  * handlers as each full message is read off the socket.  it returns -error,
1347  * == 0 eof, or > 0 for progress made.*/
1348 static int o2net_advance_rx(struct o2net_sock_container *sc)
1349 {
1350         struct o2net_msg *hdr;
1351         int ret = 0;
1352         void *data;
1353         size_t datalen;
1354 
1355         sclog(sc, "receiving\n");
1356         o2net_set_advance_start_time(sc);
1357 
1358         if (unlikely(sc->sc_handshake_ok == 0)) {
1359                 if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
1360                         data = page_address(sc->sc_page) + sc->sc_page_off;
1361                         datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
1362                         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1363                         if (ret > 0)
1364                                 sc->sc_page_off += ret;
1365                 }
1366 
1367                 if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
1368                         o2net_check_handshake(sc);
1369                         if (unlikely(sc->sc_handshake_ok == 0))
1370                                 ret = -EPROTO;
1371                 }
1372                 goto out;
1373         }
1374 
1375         /* do we need more header? */
1376         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1377                 data = page_address(sc->sc_page) + sc->sc_page_off;
1378                 datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
1379                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1380                 if (ret > 0) {
1381                         sc->sc_page_off += ret;
1382                         /* only swab incoming here.. we can
1383                          * only get here once as we cross from
1384                          * being under to over */
1385                         if (sc->sc_page_off == sizeof(struct o2net_msg)) {
1386                                 hdr = page_address(sc->sc_page);
1387                                 if (be16_to_cpu(hdr->data_len) >
1388                                     O2NET_MAX_PAYLOAD_BYTES)
1389                                         ret = -EOVERFLOW;
1390                         }
1391                 }
1392                 if (ret <= 0)
1393                         goto out;
1394         }
1395 
1396         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1397                 /* oof, still don't have a header */
1398                 goto out;
1399         }
1400 
1401         /* this was swabbed above when we first read it */
1402         hdr = page_address(sc->sc_page);
1403 
1404         msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
1405 
1406         /* do we need more payload? */
1407         if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
1408                 /* need more payload */
1409                 data = page_address(sc->sc_page) + sc->sc_page_off;
1410                 datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
1411                           sc->sc_page_off;
1412                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1413                 if (ret > 0)
1414                         sc->sc_page_off += ret;
1415                 if (ret <= 0)
1416                         goto out;
1417         }
1418 
1419         if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
1420                 /* we can only get here once, the first time we read
1421                  * the payload.. so set ret to progress if the handler
1422                  * works out. after calling this the message is toast */
1423                 ret = o2net_process_message(sc, hdr);
1424                 if (ret == 0)
1425                         ret = 1;
1426                 sc->sc_page_off = 0;
1427         }
1428 
1429 out:
1430         sclog(sc, "ret = %d\n", ret);
1431         o2net_set_advance_stop_time(sc);
1432         return ret;
1433 }
1434 
1435 /* this work func is triggerd by data ready.  it reads until it can read no
1436  * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
1437  * our work the work struct will be marked and we'll be called again. */
1438 static void o2net_rx_until_empty(struct work_struct *work)
1439 {
1440         struct o2net_sock_container *sc =
1441                 container_of(work, struct o2net_sock_container, sc_rx_work);
1442         int ret;
1443 
1444         do {
1445                 ret = o2net_advance_rx(sc);
1446         } while (ret > 0);
1447 
1448         if (ret <= 0 && ret != -EAGAIN) {
1449                 struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1450                 sclog(sc, "saw error %d, closing\n", ret);
1451                 /* not permanent so read failed handshake can retry */
1452                 o2net_ensure_shutdown(nn, sc, 0);
1453         }
1454 
1455         sc_put(sc);
1456 }
1457 
1458 static int o2net_set_nodelay(struct socket *sock)
1459 {
1460         int ret, val = 1;
1461         mm_segment_t oldfs;
1462 
1463         oldfs = get_fs();
1464         set_fs(KERNEL_DS);
1465 
1466         /*
1467          * Dear unsuspecting programmer,
1468          *
1469          * Don't use sock_setsockopt() for SOL_TCP.  It doesn't check its level
1470          * argument and assumes SOL_SOCKET so, say, your TCP_NODELAY will
1471          * silently turn into SO_DEBUG.
1472          *
1473          * Yours,
1474          * Keeper of hilariously fragile interfaces.
1475          */
1476         ret = sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY,
1477                                     (char __user *)&val, sizeof(val));
1478 
1479         set_fs(oldfs);
1480         return ret;
1481 }
1482 
1483 static int o2net_set_usertimeout(struct socket *sock)
1484 {
1485         int user_timeout = O2NET_TCP_USER_TIMEOUT;
1486 
1487         return kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
1488                                 (char *)&user_timeout, sizeof(user_timeout));
1489 }
1490 
1491 static void o2net_initialize_handshake(void)
1492 {
1493         o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
1494                 O2HB_MAX_WRITE_TIMEOUT_MS);
1495         o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
1496         o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
1497                 o2net_keepalive_delay());
1498         o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
1499                 o2net_reconnect_delay());
1500 }
1501 
1502 /* ------------------------------------------------------------ */
1503 
1504 /* called when a connect completes and after a sock is accepted.  the
1505  * rx path will see the response and mark the sc valid */
1506 static void o2net_sc_connect_completed(struct work_struct *work)
1507 {
1508         struct o2net_sock_container *sc =
1509                 container_of(work, struct o2net_sock_container,
1510                              sc_connect_work);
1511 
1512         mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
1513               (unsigned long long)O2NET_PROTOCOL_VERSION,
1514               (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
1515 
1516         o2net_initialize_handshake();
1517         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1518         sc_put(sc);
1519 }
1520 
1521 /* this is called as a work_struct func. */
1522 static void o2net_sc_send_keep_req(struct work_struct *work)
1523 {
1524         struct o2net_sock_container *sc =
1525                 container_of(work, struct o2net_sock_container,
1526                              sc_keepalive_work.work);
1527 
1528         o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
1529         sc_put(sc);
1530 }
1531 
1532 /* socket shutdown does a del_timer_sync against this as it tears down.
1533  * we can't start this timer until we've got to the point in sc buildup
1534  * where shutdown is going to be involved */
1535 static void o2net_idle_timer(unsigned long data)
1536 {
1537         struct o2net_sock_container *sc = (struct o2net_sock_container *)data;
1538         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1539 #ifdef CONFIG_DEBUG_FS
1540         unsigned long msecs = ktime_to_ms(ktime_get()) -
1541                 ktime_to_ms(sc->sc_tv_timer);
1542 #else
1543         unsigned long msecs = o2net_idle_timeout();
1544 #endif
1545 
1546         printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
1547                "idle for %lu.%lu secs.\n",
1548                SC_NODEF_ARGS(sc), msecs / 1000, msecs % 1000);
1549 
1550         /* idle timerout happen, don't shutdown the connection, but
1551          * make fence decision. Maybe the connection can recover before
1552          * the decision is made.
1553          */
1554         atomic_set(&nn->nn_timeout, 1);
1555         o2quo_conn_err(o2net_num_from_nn(nn));
1556         queue_delayed_work(o2net_wq, &nn->nn_still_up,
1557                         msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
1558 
1559         o2net_sc_reset_idle_timer(sc);
1560 
1561 }
1562 
1563 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
1564 {
1565         o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
1566         o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
1567                       msecs_to_jiffies(o2net_keepalive_delay()));
1568         o2net_set_sock_timer(sc);
1569         mod_timer(&sc->sc_idle_timeout,
1570                jiffies + msecs_to_jiffies(o2net_idle_timeout()));
1571 }
1572 
1573 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
1574 {
1575         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1576 
1577         /* clear fence decision since the connection recover from timeout*/
1578         if (atomic_read(&nn->nn_timeout)) {
1579                 o2quo_conn_up(o2net_num_from_nn(nn));
1580                 cancel_delayed_work(&nn->nn_still_up);
1581                 atomic_set(&nn->nn_timeout, 0);
1582         }
1583 
1584         /* Only push out an existing timer */
1585         if (timer_pending(&sc->sc_idle_timeout))
1586                 o2net_sc_reset_idle_timer(sc);
1587 }
1588 
1589 /* this work func is kicked whenever a path sets the nn state which doesn't
1590  * have valid set.  This includes seeing hb come up, losing a connection,
1591  * having a connect attempt fail, etc. This centralizes the logic which decides
1592  * if a connect attempt should be made or if we should give up and all future
1593  * transmit attempts should fail */
1594 static void o2net_start_connect(struct work_struct *work)
1595 {
1596         struct o2net_node *nn =
1597                 container_of(work, struct o2net_node, nn_connect_work.work);
1598         struct o2net_sock_container *sc = NULL;
1599         struct o2nm_node *node = NULL, *mynode = NULL;
1600         struct socket *sock = NULL;
1601         struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
1602         int ret = 0, stop;
1603         unsigned int timeout;
1604 
1605         /* if we're greater we initiate tx, otherwise we accept */
1606         if (o2nm_this_node() <= o2net_num_from_nn(nn))
1607                 goto out;
1608 
1609         /* watch for racing with tearing a node down */
1610         node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
1611         if (node == NULL) {
1612                 ret = 0;
1613                 goto out;
1614         }
1615 
1616         mynode = o2nm_get_node_by_num(o2nm_this_node());
1617         if (mynode == NULL) {
1618                 ret = 0;
1619                 goto out;
1620         }
1621 
1622         spin_lock(&nn->nn_lock);
1623         /*
1624          * see if we already have one pending or have given up.
1625          * For nn_timeout, it is set when we close the connection
1626          * because of the idle time out. So it means that we have
1627          * at least connected to that node successfully once,
1628          * now try to connect to it again.
1629          */
1630         timeout = atomic_read(&nn->nn_timeout);
1631         stop = (nn->nn_sc ||
1632                 (nn->nn_persistent_error &&
1633                 (nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
1634         spin_unlock(&nn->nn_lock);
1635         if (stop)
1636                 goto out;
1637 
1638         nn->nn_last_connect_attempt = jiffies;
1639 
1640         sc = sc_alloc(node);
1641         if (sc == NULL) {
1642                 mlog(0, "couldn't allocate sc\n");
1643                 ret = -ENOMEM;
1644                 goto out;
1645         }
1646 
1647         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1648         if (ret < 0) {
1649                 mlog(0, "can't create socket: %d\n", ret);
1650                 goto out;
1651         }
1652         sc->sc_sock = sock; /* freed by sc_kref_release */
1653 
1654         sock->sk->sk_allocation = GFP_ATOMIC;
1655 
1656         myaddr.sin_family = AF_INET;
1657         myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
1658         myaddr.sin_port = htons(0); /* any port */
1659 
1660         ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
1661                               sizeof(myaddr));
1662         if (ret) {
1663                 mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
1664                      ret, &mynode->nd_ipv4_address);
1665                 goto out;
1666         }
1667 
1668         ret = o2net_set_nodelay(sc->sc_sock);
1669         if (ret) {
1670                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1671                 goto out;
1672         }
1673 
1674         ret = o2net_set_usertimeout(sock);
1675         if (ret) {
1676                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1677                 goto out;
1678         }
1679 
1680         o2net_register_callbacks(sc->sc_sock->sk, sc);
1681 
1682         spin_lock(&nn->nn_lock);
1683         /* handshake completion will set nn->nn_sc_valid */
1684         o2net_set_nn_state(nn, sc, 0, 0);
1685         spin_unlock(&nn->nn_lock);
1686 
1687         remoteaddr.sin_family = AF_INET;
1688         remoteaddr.sin_addr.s_addr = node->nd_ipv4_address;
1689         remoteaddr.sin_port = node->nd_ipv4_port;
1690 
1691         ret = sc->sc_sock->ops->connect(sc->sc_sock,
1692                                         (struct sockaddr *)&remoteaddr,
1693                                         sizeof(remoteaddr),
1694                                         O_NONBLOCK);
1695         if (ret == -EINPROGRESS)
1696                 ret = 0;
1697 
1698 out:
1699         if (ret && sc) {
1700                 printk(KERN_NOTICE "o2net: Connect attempt to " SC_NODEF_FMT
1701                        " failed with errno %d\n", SC_NODEF_ARGS(sc), ret);
1702                 /* 0 err so that another will be queued and attempted
1703                  * from set_nn_state */
1704                 o2net_ensure_shutdown(nn, sc, 0);
1705         }
1706         if (sc)
1707                 sc_put(sc);
1708         if (node)
1709                 o2nm_node_put(node);
1710         if (mynode)
1711                 o2nm_node_put(mynode);
1712 
1713         return;
1714 }
1715 
1716 static void o2net_connect_expired(struct work_struct *work)
1717 {
1718         struct o2net_node *nn =
1719                 container_of(work, struct o2net_node, nn_connect_expired.work);
1720 
1721         spin_lock(&nn->nn_lock);
1722         if (!nn->nn_sc_valid) {
1723                 printk(KERN_NOTICE "o2net: No connection established with "
1724                        "node %u after %u.%u seconds, giving up.\n",
1725                      o2net_num_from_nn(nn),
1726                      o2net_idle_timeout() / 1000,
1727                      o2net_idle_timeout() % 1000);
1728 
1729                 o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
1730         }
1731         spin_unlock(&nn->nn_lock);
1732 }
1733 
1734 static void o2net_still_up(struct work_struct *work)
1735 {
1736         struct o2net_node *nn =
1737                 container_of(work, struct o2net_node, nn_still_up.work);
1738 
1739         o2quo_hb_still_up(o2net_num_from_nn(nn));
1740 }
1741 
1742 /* ------------------------------------------------------------ */
1743 
1744 void o2net_disconnect_node(struct o2nm_node *node)
1745 {
1746         struct o2net_node *nn = o2net_nn_from_num(node->nd_num);
1747 
1748         /* don't reconnect until it's heartbeating again */
1749         spin_lock(&nn->nn_lock);
1750         atomic_set(&nn->nn_timeout, 0);
1751         o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
1752         spin_unlock(&nn->nn_lock);
1753 
1754         if (o2net_wq) {
1755                 cancel_delayed_work(&nn->nn_connect_expired);
1756                 cancel_delayed_work(&nn->nn_connect_work);
1757                 cancel_delayed_work(&nn->nn_still_up);
1758                 flush_workqueue(o2net_wq);
1759         }
1760 }
1761 
1762 static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
1763                                   void *data)
1764 {
1765         o2quo_hb_down(node_num);
1766 
1767         if (!node)
1768                 return;
1769 
1770         if (node_num != o2nm_this_node())
1771                 o2net_disconnect_node(node);
1772 
1773         BUG_ON(atomic_read(&o2net_connected_peers) < 0);
1774 }
1775 
1776 static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
1777                                 void *data)
1778 {
1779         struct o2net_node *nn = o2net_nn_from_num(node_num);
1780 
1781         o2quo_hb_up(node_num);
1782 
1783         BUG_ON(!node);
1784 
1785         /* ensure an immediate connect attempt */
1786         nn->nn_last_connect_attempt = jiffies -
1787                 (msecs_to_jiffies(o2net_reconnect_delay()) + 1);
1788 
1789         if (node_num != o2nm_this_node()) {
1790                 /* believe it or not, accept and node hearbeating testing
1791                  * can succeed for this node before we got here.. so
1792                  * only use set_nn_state to clear the persistent error
1793                  * if that hasn't already happened */
1794                 spin_lock(&nn->nn_lock);
1795                 atomic_set(&nn->nn_timeout, 0);
1796                 if (nn->nn_persistent_error)
1797                         o2net_set_nn_state(nn, NULL, 0, 0);
1798                 spin_unlock(&nn->nn_lock);
1799         }
1800 }
1801 
1802 void o2net_unregister_hb_callbacks(void)
1803 {
1804         o2hb_unregister_callback(NULL, &o2net_hb_up);
1805         o2hb_unregister_callback(NULL, &o2net_hb_down);
1806 }
1807 
1808 int o2net_register_hb_callbacks(void)
1809 {
1810         int ret;
1811 
1812         o2hb_setup_callback(&o2net_hb_down, O2HB_NODE_DOWN_CB,
1813                             o2net_hb_node_down_cb, NULL, O2NET_HB_PRI);
1814         o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
1815                             o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
1816 
1817         ret = o2hb_register_callback(NULL, &o2net_hb_up);
1818         if (ret == 0)
1819                 ret = o2hb_register_callback(NULL, &o2net_hb_down);
1820 
1821         if (ret)
1822                 o2net_unregister_hb_callbacks();
1823 
1824         return ret;
1825 }
1826 
1827 /* ------------------------------------------------------------ */
1828 
1829 static int o2net_accept_one(struct socket *sock, int *more)
1830 {
1831         int ret, slen;
1832         struct sockaddr_in sin;
1833         struct socket *new_sock = NULL;
1834         struct o2nm_node *node = NULL;
1835         struct o2nm_node *local_node = NULL;
1836         struct o2net_sock_container *sc = NULL;
1837         struct o2net_node *nn;
1838 
1839         BUG_ON(sock == NULL);
1840         *more = 0;
1841         ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
1842                                sock->sk->sk_protocol, &new_sock);
1843         if (ret)
1844                 goto out;
1845 
1846         new_sock->type = sock->type;
1847         new_sock->ops = sock->ops;
1848         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
1849         if (ret < 0)
1850                 goto out;
1851 
1852         *more = 1;
1853         new_sock->sk->sk_allocation = GFP_ATOMIC;
1854 
1855         ret = o2net_set_nodelay(new_sock);
1856         if (ret) {
1857                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1858                 goto out;
1859         }
1860 
1861         ret = o2net_set_usertimeout(new_sock);
1862         if (ret) {
1863                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1864                 goto out;
1865         }
1866 
1867         slen = sizeof(sin);
1868         ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin,
1869                                        &slen, 1);
1870         if (ret < 0)
1871                 goto out;
1872 
1873         node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
1874         if (node == NULL) {
1875                 printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
1876                        "node at %pI4:%d\n", &sin.sin_addr.s_addr,
1877                        ntohs(sin.sin_port));
1878                 ret = -EINVAL;
1879                 goto out;
1880         }
1881 
1882         if (o2nm_this_node() >= node->nd_num) {
1883                 local_node = o2nm_get_node_by_num(o2nm_this_node());
1884                 if (local_node)
1885                         printk(KERN_NOTICE "o2net: Unexpected connect attempt "
1886                                         "seen at node '%s' (%u, %pI4:%d) from "
1887                                         "node '%s' (%u, %pI4:%d)\n",
1888                                         local_node->nd_name, local_node->nd_num,
1889                                         &(local_node->nd_ipv4_address),
1890                                         ntohs(local_node->nd_ipv4_port),
1891                                         node->nd_name,
1892                                         node->nd_num, &sin.sin_addr.s_addr,
1893                                         ntohs(sin.sin_port));
1894                 ret = -EINVAL;
1895                 goto out;
1896         }
1897 
1898         /* this happens all the time when the other node sees our heartbeat
1899          * and tries to connect before we see their heartbeat */
1900         if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
1901                 mlog(ML_CONN, "attempt to connect from node '%s' at "
1902                      "%pI4:%d but it isn't heartbeating\n",
1903                      node->nd_name, &sin.sin_addr.s_addr,
1904                      ntohs(sin.sin_port));
1905                 ret = -EINVAL;
1906                 goto out;
1907         }
1908 
1909         nn = o2net_nn_from_num(node->nd_num);
1910 
1911         spin_lock(&nn->nn_lock);
1912         if (nn->nn_sc)
1913                 ret = -EBUSY;
1914         else
1915                 ret = 0;
1916         spin_unlock(&nn->nn_lock);
1917         if (ret) {
1918                 printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
1919                        "at %pI4:%d but it already has an open connection\n",
1920                        node->nd_name, &sin.sin_addr.s_addr,
1921                        ntohs(sin.sin_port));
1922                 goto out;
1923         }
1924 
1925         sc = sc_alloc(node);
1926         if (sc == NULL) {
1927                 ret = -ENOMEM;
1928                 goto out;
1929         }
1930 
1931         sc->sc_sock = new_sock;
1932         new_sock = NULL;
1933 
1934         spin_lock(&nn->nn_lock);
1935         atomic_set(&nn->nn_timeout, 0);
1936         o2net_set_nn_state(nn, sc, 0, 0);
1937         spin_unlock(&nn->nn_lock);
1938 
1939         o2net_register_callbacks(sc->sc_sock->sk, sc);
1940         o2net_sc_queue_work(sc, &sc->sc_rx_work);
1941 
1942         o2net_initialize_handshake();
1943         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1944 
1945 out:
1946         if (new_sock)
1947                 sock_release(new_sock);
1948         if (node)
1949                 o2nm_node_put(node);
1950         if (local_node)
1951                 o2nm_node_put(local_node);
1952         if (sc)
1953                 sc_put(sc);
1954         return ret;
1955 }
1956 
1957 /*
1958  * This function is invoked in response to one or more
1959  * pending accepts at softIRQ level. We must drain the
1960  * entire que before returning.
1961  */
1962 
1963 static void o2net_accept_many(struct work_struct *work)
1964 {
1965         struct socket *sock = o2net_listen_sock;
1966         int     more;
1967         int     err;
1968 
1969         /*
1970          * It is critical to note that due to interrupt moderation
1971          * at the network driver level, we can't assume to get a
1972          * softIRQ for every single conn since tcp SYN packets
1973          * can arrive back-to-back, and therefore many pending
1974          * accepts may result in just 1 softIRQ. If we terminate
1975          * the o2net_accept_one() loop upon seeing an err, what happens
1976          * to the rest of the conns in the queue? If no new SYN
1977          * arrives for hours, no softIRQ  will be delivered,
1978          * and the connections will just sit in the queue.
1979          */
1980 
1981         for (;;) {
1982                 err = o2net_accept_one(sock, &more);
1983                 if (!more)
1984                         break;
1985                 cond_resched();
1986         }
1987 }
1988 
1989 static void o2net_listen_data_ready(struct sock *sk)
1990 {
1991         void (*ready)(struct sock *sk);
1992 
1993         read_lock(&sk->sk_callback_lock);
1994         ready = sk->sk_user_data;
1995         if (ready == NULL) { /* check for teardown race */
1996                 ready = sk->sk_data_ready;
1997                 goto out;
1998         }
1999 
2000         /* This callback may called twice when a new connection
2001          * is  being established as a child socket inherits everything
2002          * from a parent LISTEN socket, including the data_ready cb of
2003          * the parent. This leads to a hazard. In o2net_accept_one()
2004          * we are still initializing the child socket but have not
2005          * changed the inherited data_ready callback yet when
2006          * data starts arriving.
2007          * We avoid this hazard by checking the state.
2008          * For the listening socket,  the state will be TCP_LISTEN; for the new
2009          * socket, will be  TCP_ESTABLISHED. Also, in this case,
2010          * sk->sk_user_data is not a valid function pointer.
2011          */
2012 
2013         if (sk->sk_state == TCP_LISTEN) {
2014                 queue_work(o2net_wq, &o2net_listen_work);
2015         } else {
2016                 ready = NULL;
2017         }
2018 
2019 out:
2020         read_unlock(&sk->sk_callback_lock);
2021         if (ready != NULL)
2022                 ready(sk);
2023 }
2024 
2025 static int o2net_open_listening_sock(__be32 addr, __be16 port)
2026 {
2027         struct socket *sock = NULL;
2028         int ret;
2029         struct sockaddr_in sin = {
2030                 .sin_family = PF_INET,
2031                 .sin_addr = { .s_addr = addr },
2032                 .sin_port = port,
2033         };
2034 
2035         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
2036         if (ret < 0) {
2037                 printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
2038                 goto out;
2039         }
2040 
2041         sock->sk->sk_allocation = GFP_ATOMIC;
2042 
2043         write_lock_bh(&sock->sk->sk_callback_lock);
2044         sock->sk->sk_user_data = sock->sk->sk_data_ready;
2045         sock->sk->sk_data_ready = o2net_listen_data_ready;
2046         write_unlock_bh(&sock->sk->sk_callback_lock);
2047 
2048         o2net_listen_sock = sock;
2049         INIT_WORK(&o2net_listen_work, o2net_accept_many);
2050 
2051         sock->sk->sk_reuse = SK_CAN_REUSE;
2052         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
2053         if (ret < 0) {
2054                 printk(KERN_ERR "o2net: Error %d while binding socket at "
2055                        "%pI4:%u\n", ret, &addr, ntohs(port)); 
2056                 goto out;
2057         }
2058 
2059         ret = sock->ops->listen(sock, 64);
2060         if (ret < 0)
2061                 printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
2062                        ret, &addr, ntohs(port));
2063 
2064 out:
2065         if (ret) {
2066                 o2net_listen_sock = NULL;
2067                 if (sock)
2068                         sock_release(sock);
2069         }
2070         return ret;
2071 }
2072 
2073 /*
2074  * called from node manager when we should bring up our network listening
2075  * socket.  node manager handles all the serialization to only call this
2076  * once and to match it with o2net_stop_listening().  note,
2077  * o2nm_this_node() doesn't work yet as we're being called while it
2078  * is being set up.
2079  */
2080 int o2net_start_listening(struct o2nm_node *node)
2081 {
2082         int ret = 0;
2083 
2084         BUG_ON(o2net_wq != NULL);
2085         BUG_ON(o2net_listen_sock != NULL);
2086 
2087         mlog(ML_KTHREAD, "starting o2net thread...\n");
2088         o2net_wq = create_singlethread_workqueue("o2net");
2089         if (o2net_wq == NULL) {
2090                 mlog(ML_ERROR, "unable to launch o2net thread\n");
2091                 return -ENOMEM; /* ? */
2092         }
2093 
2094         ret = o2net_open_listening_sock(node->nd_ipv4_address,
2095                                         node->nd_ipv4_port);
2096         if (ret) {
2097                 destroy_workqueue(o2net_wq);
2098                 o2net_wq = NULL;
2099         } else
2100                 o2quo_conn_up(node->nd_num);
2101 
2102         return ret;
2103 }
2104 
2105 /* again, o2nm_this_node() doesn't work here as we're involved in
2106  * tearing it down */
2107 void o2net_stop_listening(struct o2nm_node *node)
2108 {
2109         struct socket *sock = o2net_listen_sock;
2110         size_t i;
2111 
2112         BUG_ON(o2net_wq == NULL);
2113         BUG_ON(o2net_listen_sock == NULL);
2114 
2115         /* stop the listening socket from generating work */
2116         write_lock_bh(&sock->sk->sk_callback_lock);
2117         sock->sk->sk_data_ready = sock->sk->sk_user_data;
2118         sock->sk->sk_user_data = NULL;
2119         write_unlock_bh(&sock->sk->sk_callback_lock);
2120 
2121         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2122                 struct o2nm_node *node = o2nm_get_node_by_num(i);
2123                 if (node) {
2124                         o2net_disconnect_node(node);
2125                         o2nm_node_put(node);
2126                 }
2127         }
2128 
2129         /* finish all work and tear down the work queue */
2130         mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
2131         destroy_workqueue(o2net_wq);
2132         o2net_wq = NULL;
2133 
2134         sock_release(o2net_listen_sock);
2135         o2net_listen_sock = NULL;
2136 
2137         o2quo_conn_err(node->nd_num);
2138 }
2139 
2140 /* ------------------------------------------------------------ */
2141 
2142 int o2net_init(void)
2143 {
2144         unsigned long i;
2145 
2146         o2quo_init();
2147 
2148         if (o2net_debugfs_init())
2149                 return -ENOMEM;
2150 
2151         o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
2152         o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2153         o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2154         if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp) {
2155                 kfree(o2net_hand);
2156                 kfree(o2net_keep_req);
2157                 kfree(o2net_keep_resp);
2158                 return -ENOMEM;
2159         }
2160 
2161         o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
2162         o2net_hand->connector_id = cpu_to_be64(1);
2163 
2164         o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
2165         o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
2166 
2167         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2168                 struct o2net_node *nn = o2net_nn_from_num(i);
2169 
2170                 atomic_set(&nn->nn_timeout, 0);
2171                 spin_lock_init(&nn->nn_lock);
2172                 INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
2173                 INIT_DELAYED_WORK(&nn->nn_connect_expired,
2174                                   o2net_connect_expired);
2175                 INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
2176                 /* until we see hb from a node we'll return einval */
2177                 nn->nn_persistent_error = -ENOTCONN;
2178                 init_waitqueue_head(&nn->nn_sc_wq);
2179                 idr_init(&nn->nn_status_idr);
2180                 INIT_LIST_HEAD(&nn->nn_status_list);
2181         }
2182 
2183         return 0;
2184 }
2185 
2186 void o2net_exit(void)
2187 {
2188         o2quo_exit();
2189         kfree(o2net_hand);
2190         kfree(o2net_keep_req);
2191         kfree(o2net_keep_resp);
2192         o2net_debugfs_exit();
2193 }
2194 

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