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

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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 = NULL;
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, int bytes);
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 int o2net_reconnect_delay(void)
266 {
267         return o2nm_single_cluster->cl_reconnect_delay_ms;
268 }
269 
270 static inline int o2net_keepalive_delay(void)
271 {
272         return o2nm_single_cluster->cl_keepalive_delay_ms;
273 }
274 
275 static inline 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, int bytes)
601 {
602         void (*ready)(struct sock *sk, int bytes);
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, bytes);
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         int ret;
920         mm_segment_t oldfs;
921         struct kvec vec = {
922                 .iov_len = len,
923                 .iov_base = data,
924         };
925         struct msghdr msg = {
926                 .msg_iovlen = 1,
927                 .msg_iov = (struct iovec *)&vec,
928                 .msg_flags = MSG_DONTWAIT,
929         };
930 
931         oldfs = get_fs();
932         set_fs(get_ds());
933         ret = sock_recvmsg(sock, &msg, len, msg.msg_flags);
934         set_fs(oldfs);
935 
936         return ret;
937 }
938 
939 static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
940                               size_t veclen, size_t total)
941 {
942         int ret;
943         mm_segment_t oldfs;
944         struct msghdr msg = {
945                 .msg_iov = (struct iovec *)vec,
946                 .msg_iovlen = veclen,
947         };
948 
949         if (sock == NULL) {
950                 ret = -EINVAL;
951                 goto out;
952         }
953 
954         oldfs = get_fs();
955         set_fs(get_ds());
956         ret = sock_sendmsg(sock, &msg, total);
957         set_fs(oldfs);
958         if (ret != total) {
959                 mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret,
960                      total);
961                 if (ret >= 0)
962                         ret = -EPIPE; /* should be smarter, I bet */
963                 goto out;
964         }
965 
966         ret = 0;
967 out:
968         if (ret < 0)
969                 mlog(0, "returning error: %d\n", ret);
970         return ret;
971 }
972 
973 static void o2net_sendpage(struct o2net_sock_container *sc,
974                            void *kmalloced_virt,
975                            size_t size)
976 {
977         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
978         ssize_t ret;
979 
980         while (1) {
981                 mutex_lock(&sc->sc_send_lock);
982                 ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
983                                                  virt_to_page(kmalloced_virt),
984                                                  (long)kmalloced_virt & ~PAGE_MASK,
985                                                  size, MSG_DONTWAIT);
986                 mutex_unlock(&sc->sc_send_lock);
987                 if (ret == size)
988                         break;
989                 if (ret == (ssize_t)-EAGAIN) {
990                         mlog(0, "sendpage of size %zu to " SC_NODEF_FMT
991                              " returned EAGAIN\n", size, SC_NODEF_ARGS(sc));
992                         cond_resched();
993                         continue;
994                 }
995                 mlog(ML_ERROR, "sendpage of size %zu to " SC_NODEF_FMT
996                      " failed with %zd\n", size, SC_NODEF_ARGS(sc), ret);
997                 o2net_ensure_shutdown(nn, sc, 0);
998                 break;
999         }
1000 }
1001 
1002 static void o2net_init_msg(struct o2net_msg *msg, u16 data_len, u16 msg_type, u32 key)
1003 {
1004         memset(msg, 0, sizeof(struct o2net_msg));
1005         msg->magic = cpu_to_be16(O2NET_MSG_MAGIC);
1006         msg->data_len = cpu_to_be16(data_len);
1007         msg->msg_type = cpu_to_be16(msg_type);
1008         msg->sys_status = cpu_to_be32(O2NET_ERR_NONE);
1009         msg->status = 0;
1010         msg->key = cpu_to_be32(key);
1011 }
1012 
1013 static int o2net_tx_can_proceed(struct o2net_node *nn,
1014                                 struct o2net_sock_container **sc_ret,
1015                                 int *error)
1016 {
1017         int ret = 0;
1018 
1019         spin_lock(&nn->nn_lock);
1020         if (nn->nn_persistent_error) {
1021                 ret = 1;
1022                 *sc_ret = NULL;
1023                 *error = nn->nn_persistent_error;
1024         } else if (nn->nn_sc_valid) {
1025                 kref_get(&nn->nn_sc->sc_kref);
1026 
1027                 ret = 1;
1028                 *sc_ret = nn->nn_sc;
1029                 *error = 0;
1030         }
1031         spin_unlock(&nn->nn_lock);
1032 
1033         return ret;
1034 }
1035 
1036 /* Get a map of all nodes to which this node is currently connected to */
1037 void o2net_fill_node_map(unsigned long *map, unsigned bytes)
1038 {
1039         struct o2net_sock_container *sc;
1040         int node, ret;
1041 
1042         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1043 
1044         memset(map, 0, bytes);
1045         for (node = 0; node < O2NM_MAX_NODES; ++node) {
1046                 o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret);
1047                 if (!ret) {
1048                         set_bit(node, map);
1049                         sc_put(sc);
1050                 }
1051         }
1052 }
1053 EXPORT_SYMBOL_GPL(o2net_fill_node_map);
1054 
1055 int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
1056                            size_t caller_veclen, u8 target_node, int *status)
1057 {
1058         int ret = 0;
1059         struct o2net_msg *msg = NULL;
1060         size_t veclen, caller_bytes = 0;
1061         struct kvec *vec = NULL;
1062         struct o2net_sock_container *sc = NULL;
1063         struct o2net_node *nn = o2net_nn_from_num(target_node);
1064         struct o2net_status_wait nsw = {
1065                 .ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
1066         };
1067         struct o2net_send_tracking nst;
1068 
1069         o2net_init_nst(&nst, msg_type, key, current, target_node);
1070 
1071         if (o2net_wq == NULL) {
1072                 mlog(0, "attempt to tx without o2netd running\n");
1073                 ret = -ESRCH;
1074                 goto out;
1075         }
1076 
1077         if (caller_veclen == 0) {
1078                 mlog(0, "bad kvec array length\n");
1079                 ret = -EINVAL;
1080                 goto out;
1081         }
1082 
1083         caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
1084         if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
1085                 mlog(0, "total payload len %zu too large\n", caller_bytes);
1086                 ret = -EINVAL;
1087                 goto out;
1088         }
1089 
1090         if (target_node == o2nm_this_node()) {
1091                 ret = -ELOOP;
1092                 goto out;
1093         }
1094 
1095         o2net_debug_add_nst(&nst);
1096 
1097         o2net_set_nst_sock_time(&nst);
1098 
1099         wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
1100         if (ret)
1101                 goto out;
1102 
1103         o2net_set_nst_sock_container(&nst, sc);
1104 
1105         veclen = caller_veclen + 1;
1106         vec = kmalloc(sizeof(struct kvec) * veclen, GFP_ATOMIC);
1107         if (vec == NULL) {
1108                 mlog(0, "failed to %zu element kvec!\n", veclen);
1109                 ret = -ENOMEM;
1110                 goto out;
1111         }
1112 
1113         msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
1114         if (!msg) {
1115                 mlog(0, "failed to allocate a o2net_msg!\n");
1116                 ret = -ENOMEM;
1117                 goto out;
1118         }
1119 
1120         o2net_init_msg(msg, caller_bytes, msg_type, key);
1121 
1122         vec[0].iov_len = sizeof(struct o2net_msg);
1123         vec[0].iov_base = msg;
1124         memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
1125 
1126         ret = o2net_prep_nsw(nn, &nsw);
1127         if (ret)
1128                 goto out;
1129 
1130         msg->msg_num = cpu_to_be32(nsw.ns_id);
1131         o2net_set_nst_msg_id(&nst, nsw.ns_id);
1132 
1133         o2net_set_nst_send_time(&nst);
1134 
1135         /* finally, convert the message header to network byte-order
1136          * and send */
1137         mutex_lock(&sc->sc_send_lock);
1138         ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
1139                                  sizeof(struct o2net_msg) + caller_bytes);
1140         mutex_unlock(&sc->sc_send_lock);
1141         msglog(msg, "sending returned %d\n", ret);
1142         if (ret < 0) {
1143                 mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
1144                 goto out;
1145         }
1146 
1147         /* wait on other node's handler */
1148         o2net_set_nst_status_time(&nst);
1149         wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
1150 
1151         o2net_update_send_stats(&nst, sc);
1152 
1153         /* Note that we avoid overwriting the callers status return
1154          * variable if a system error was reported on the other
1155          * side. Callers beware. */
1156         ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
1157         if (status && !ret)
1158                 *status = nsw.ns_status;
1159 
1160         mlog(0, "woken, returning system status %d, user status %d\n",
1161              ret, nsw.ns_status);
1162 out:
1163         o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
1164         if (sc)
1165                 sc_put(sc);
1166         kfree(vec);
1167         kfree(msg);
1168         o2net_complete_nsw(nn, &nsw, 0, 0, 0);
1169         return ret;
1170 }
1171 EXPORT_SYMBOL_GPL(o2net_send_message_vec);
1172 
1173 int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
1174                        u8 target_node, int *status)
1175 {
1176         struct kvec vec = {
1177                 .iov_base = data,
1178                 .iov_len = len,
1179         };
1180         return o2net_send_message_vec(msg_type, key, &vec, 1,
1181                                       target_node, status);
1182 }
1183 EXPORT_SYMBOL_GPL(o2net_send_message);
1184 
1185 static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
1186                                    enum o2net_system_error syserr, int err)
1187 {
1188         struct kvec vec = {
1189                 .iov_base = hdr,
1190                 .iov_len = sizeof(struct o2net_msg),
1191         };
1192 
1193         BUG_ON(syserr >= O2NET_ERR_MAX);
1194 
1195         /* leave other fields intact from the incoming message, msg_num
1196          * in particular */
1197         hdr->sys_status = cpu_to_be32(syserr);
1198         hdr->status = cpu_to_be32(err);
1199         hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
1200         hdr->data_len = 0;
1201 
1202         msglog(hdr, "about to send status magic %d\n", err);
1203         /* hdr has been in host byteorder this whole time */
1204         return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
1205 }
1206 
1207 /* this returns -errno if the header was unknown or too large, etc.
1208  * after this is called the buffer us reused for the next message */
1209 static int o2net_process_message(struct o2net_sock_container *sc,
1210                                  struct o2net_msg *hdr)
1211 {
1212         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1213         int ret = 0, handler_status;
1214         enum  o2net_system_error syserr;
1215         struct o2net_msg_handler *nmh = NULL;
1216         void *ret_data = NULL;
1217 
1218         msglog(hdr, "processing message\n");
1219 
1220         o2net_sc_postpone_idle(sc);
1221 
1222         switch(be16_to_cpu(hdr->magic)) {
1223                 case O2NET_MSG_STATUS_MAGIC:
1224                         /* special type for returning message status */
1225                         o2net_complete_nsw(nn, NULL,
1226                                            be32_to_cpu(hdr->msg_num),
1227                                            be32_to_cpu(hdr->sys_status),
1228                                            be32_to_cpu(hdr->status));
1229                         goto out;
1230                 case O2NET_MSG_KEEP_REQ_MAGIC:
1231                         o2net_sendpage(sc, o2net_keep_resp,
1232                                        sizeof(*o2net_keep_resp));
1233                         goto out;
1234                 case O2NET_MSG_KEEP_RESP_MAGIC:
1235                         goto out;
1236                 case O2NET_MSG_MAGIC:
1237                         break;
1238                 default:
1239                         msglog(hdr, "bad magic\n");
1240                         ret = -EINVAL;
1241                         goto out;
1242                         break;
1243         }
1244 
1245         /* find a handler for it */
1246         handler_status = 0;
1247         nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
1248                                 be32_to_cpu(hdr->key));
1249         if (!nmh) {
1250                 mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
1251                      be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
1252                 syserr = O2NET_ERR_NO_HNDLR;
1253                 goto out_respond;
1254         }
1255 
1256         syserr = O2NET_ERR_NONE;
1257 
1258         if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
1259                 syserr = O2NET_ERR_OVERFLOW;
1260 
1261         if (syserr != O2NET_ERR_NONE)
1262                 goto out_respond;
1263 
1264         o2net_set_func_start_time(sc);
1265         sc->sc_msg_key = be32_to_cpu(hdr->key);
1266         sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
1267         handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
1268                                              be16_to_cpu(hdr->data_len),
1269                                         nmh->nh_func_data, &ret_data);
1270         o2net_set_func_stop_time(sc);
1271 
1272         o2net_update_recv_stats(sc);
1273 
1274 out_respond:
1275         /* this destroys the hdr, so don't use it after this */
1276         mutex_lock(&sc->sc_send_lock);
1277         ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
1278                                       handler_status);
1279         mutex_unlock(&sc->sc_send_lock);
1280         hdr = NULL;
1281         mlog(0, "sending handler status %d, syserr %d returned %d\n",
1282              handler_status, syserr, ret);
1283 
1284         if (nmh) {
1285                 BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
1286                 if (nmh->nh_post_func)
1287                         (nmh->nh_post_func)(handler_status, nmh->nh_func_data,
1288                                             ret_data);
1289         }
1290 
1291 out:
1292         if (nmh)
1293                 o2net_handler_put(nmh);
1294         return ret;
1295 }
1296 
1297 static int o2net_check_handshake(struct o2net_sock_container *sc)
1298 {
1299         struct o2net_handshake *hand = page_address(sc->sc_page);
1300         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1301 
1302         if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
1303                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
1304                        "protocol version %llu but %llu is required. "
1305                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1306                        (unsigned long long)be64_to_cpu(hand->protocol_version),
1307                        O2NET_PROTOCOL_VERSION);
1308 
1309                 /* don't bother reconnecting if its the wrong version. */
1310                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1311                 return -1;
1312         }
1313 
1314         /*
1315          * Ensure timeouts are consistent with other nodes, otherwise
1316          * we can end up with one node thinking that the other must be down,
1317          * but isn't. This can ultimately cause corruption.
1318          */
1319         if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
1320                                 o2net_idle_timeout()) {
1321                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
1322                        "idle timeout of %u ms, but we use %u ms locally. "
1323                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1324                        be32_to_cpu(hand->o2net_idle_timeout_ms),
1325                        o2net_idle_timeout());
1326                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1327                 return -1;
1328         }
1329 
1330         if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
1331                         o2net_keepalive_delay()) {
1332                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
1333                        "delay of %u ms, but we use %u ms locally. "
1334                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1335                        be32_to_cpu(hand->o2net_keepalive_delay_ms),
1336                        o2net_keepalive_delay());
1337                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1338                 return -1;
1339         }
1340 
1341         if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
1342                         O2HB_MAX_WRITE_TIMEOUT_MS) {
1343                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
1344                        "timeout of %u ms, but we use %u ms locally. "
1345                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1346                        be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
1347                        O2HB_MAX_WRITE_TIMEOUT_MS);
1348                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1349                 return -1;
1350         }
1351 
1352         sc->sc_handshake_ok = 1;
1353 
1354         spin_lock(&nn->nn_lock);
1355         /* set valid and queue the idle timers only if it hasn't been
1356          * shut down already */
1357         if (nn->nn_sc == sc) {
1358                 o2net_sc_reset_idle_timer(sc);
1359                 atomic_set(&nn->nn_timeout, 0);
1360                 o2net_set_nn_state(nn, sc, 1, 0);
1361         }
1362         spin_unlock(&nn->nn_lock);
1363 
1364         /* shift everything up as though it wasn't there */
1365         sc->sc_page_off -= sizeof(struct o2net_handshake);
1366         if (sc->sc_page_off)
1367                 memmove(hand, hand + 1, sc->sc_page_off);
1368 
1369         return 0;
1370 }
1371 
1372 /* this demuxes the queued rx bytes into header or payload bits and calls
1373  * handlers as each full message is read off the socket.  it returns -error,
1374  * == 0 eof, or > 0 for progress made.*/
1375 static int o2net_advance_rx(struct o2net_sock_container *sc)
1376 {
1377         struct o2net_msg *hdr;
1378         int ret = 0;
1379         void *data;
1380         size_t datalen;
1381 
1382         sclog(sc, "receiving\n");
1383         o2net_set_advance_start_time(sc);
1384 
1385         if (unlikely(sc->sc_handshake_ok == 0)) {
1386                 if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
1387                         data = page_address(sc->sc_page) + sc->sc_page_off;
1388                         datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
1389                         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1390                         if (ret > 0)
1391                                 sc->sc_page_off += ret;
1392                 }
1393 
1394                 if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
1395                         o2net_check_handshake(sc);
1396                         if (unlikely(sc->sc_handshake_ok == 0))
1397                                 ret = -EPROTO;
1398                 }
1399                 goto out;
1400         }
1401 
1402         /* do we need more header? */
1403         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1404                 data = page_address(sc->sc_page) + sc->sc_page_off;
1405                 datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
1406                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1407                 if (ret > 0) {
1408                         sc->sc_page_off += ret;
1409                         /* only swab incoming here.. we can
1410                          * only get here once as we cross from
1411                          * being under to over */
1412                         if (sc->sc_page_off == sizeof(struct o2net_msg)) {
1413                                 hdr = page_address(sc->sc_page);
1414                                 if (be16_to_cpu(hdr->data_len) >
1415                                     O2NET_MAX_PAYLOAD_BYTES)
1416                                         ret = -EOVERFLOW;
1417                         }
1418                 }
1419                 if (ret <= 0)
1420                         goto out;
1421         }
1422 
1423         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1424                 /* oof, still don't have a header */
1425                 goto out;
1426         }
1427 
1428         /* this was swabbed above when we first read it */
1429         hdr = page_address(sc->sc_page);
1430 
1431         msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
1432 
1433         /* do we need more payload? */
1434         if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
1435                 /* need more payload */
1436                 data = page_address(sc->sc_page) + sc->sc_page_off;
1437                 datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
1438                           sc->sc_page_off;
1439                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1440                 if (ret > 0)
1441                         sc->sc_page_off += ret;
1442                 if (ret <= 0)
1443                         goto out;
1444         }
1445 
1446         if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
1447                 /* we can only get here once, the first time we read
1448                  * the payload.. so set ret to progress if the handler
1449                  * works out. after calling this the message is toast */
1450                 ret = o2net_process_message(sc, hdr);
1451                 if (ret == 0)
1452                         ret = 1;
1453                 sc->sc_page_off = 0;
1454         }
1455 
1456 out:
1457         sclog(sc, "ret = %d\n", ret);
1458         o2net_set_advance_stop_time(sc);
1459         return ret;
1460 }
1461 
1462 /* this work func is triggerd by data ready.  it reads until it can read no
1463  * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
1464  * our work the work struct will be marked and we'll be called again. */
1465 static void o2net_rx_until_empty(struct work_struct *work)
1466 {
1467         struct o2net_sock_container *sc =
1468                 container_of(work, struct o2net_sock_container, sc_rx_work);
1469         int ret;
1470 
1471         do {
1472                 ret = o2net_advance_rx(sc);
1473         } while (ret > 0);
1474 
1475         if (ret <= 0 && ret != -EAGAIN) {
1476                 struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1477                 sclog(sc, "saw error %d, closing\n", ret);
1478                 /* not permanent so read failed handshake can retry */
1479                 o2net_ensure_shutdown(nn, sc, 0);
1480         }
1481 
1482         sc_put(sc);
1483 }
1484 
1485 static int o2net_set_nodelay(struct socket *sock)
1486 {
1487         int ret, val = 1;
1488         mm_segment_t oldfs;
1489 
1490         oldfs = get_fs();
1491         set_fs(KERNEL_DS);
1492 
1493         /*
1494          * Dear unsuspecting programmer,
1495          *
1496          * Don't use sock_setsockopt() for SOL_TCP.  It doesn't check its level
1497          * argument and assumes SOL_SOCKET so, say, your TCP_NODELAY will
1498          * silently turn into SO_DEBUG.
1499          *
1500          * Yours,
1501          * Keeper of hilariously fragile interfaces.
1502          */
1503         ret = sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY,
1504                                     (char __user *)&val, sizeof(val));
1505 
1506         set_fs(oldfs);
1507         return ret;
1508 }
1509 
1510 static void o2net_initialize_handshake(void)
1511 {
1512         o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
1513                 O2HB_MAX_WRITE_TIMEOUT_MS);
1514         o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
1515         o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
1516                 o2net_keepalive_delay());
1517         o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
1518                 o2net_reconnect_delay());
1519 }
1520 
1521 /* ------------------------------------------------------------ */
1522 
1523 /* called when a connect completes and after a sock is accepted.  the
1524  * rx path will see the response and mark the sc valid */
1525 static void o2net_sc_connect_completed(struct work_struct *work)
1526 {
1527         struct o2net_sock_container *sc =
1528                 container_of(work, struct o2net_sock_container,
1529                              sc_connect_work);
1530 
1531         mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
1532               (unsigned long long)O2NET_PROTOCOL_VERSION,
1533               (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
1534 
1535         o2net_initialize_handshake();
1536         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1537         sc_put(sc);
1538 }
1539 
1540 /* this is called as a work_struct func. */
1541 static void o2net_sc_send_keep_req(struct work_struct *work)
1542 {
1543         struct o2net_sock_container *sc =
1544                 container_of(work, struct o2net_sock_container,
1545                              sc_keepalive_work.work);
1546 
1547         o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
1548         sc_put(sc);
1549 }
1550 
1551 /* socket shutdown does a del_timer_sync against this as it tears down.
1552  * we can't start this timer until we've got to the point in sc buildup
1553  * where shutdown is going to be involved */
1554 static void o2net_idle_timer(unsigned long data)
1555 {
1556         struct o2net_sock_container *sc = (struct o2net_sock_container *)data;
1557         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1558 #ifdef CONFIG_DEBUG_FS
1559         unsigned long msecs = ktime_to_ms(ktime_get()) -
1560                 ktime_to_ms(sc->sc_tv_timer);
1561 #else
1562         unsigned long msecs = o2net_idle_timeout();
1563 #endif
1564 
1565         printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
1566                "idle for %lu.%lu secs, shutting it down.\n", SC_NODEF_ARGS(sc),
1567                msecs / 1000, msecs % 1000);
1568 
1569         /*
1570          * Initialize the nn_timeout so that the next connection attempt
1571          * will continue in o2net_start_connect.
1572          */
1573         atomic_set(&nn->nn_timeout, 1);
1574 
1575         o2net_sc_queue_work(sc, &sc->sc_shutdown_work);
1576 }
1577 
1578 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
1579 {
1580         o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
1581         o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
1582                       msecs_to_jiffies(o2net_keepalive_delay()));
1583         o2net_set_sock_timer(sc);
1584         mod_timer(&sc->sc_idle_timeout,
1585                jiffies + msecs_to_jiffies(o2net_idle_timeout()));
1586 }
1587 
1588 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
1589 {
1590         /* Only push out an existing timer */
1591         if (timer_pending(&sc->sc_idle_timeout))
1592                 o2net_sc_reset_idle_timer(sc);
1593 }
1594 
1595 /* this work func is kicked whenever a path sets the nn state which doesn't
1596  * have valid set.  This includes seeing hb come up, losing a connection,
1597  * having a connect attempt fail, etc. This centralizes the logic which decides
1598  * if a connect attempt should be made or if we should give up and all future
1599  * transmit attempts should fail */
1600 static void o2net_start_connect(struct work_struct *work)
1601 {
1602         struct o2net_node *nn =
1603                 container_of(work, struct o2net_node, nn_connect_work.work);
1604         struct o2net_sock_container *sc = NULL;
1605         struct o2nm_node *node = NULL, *mynode = NULL;
1606         struct socket *sock = NULL;
1607         struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
1608         int ret = 0, stop;
1609         unsigned int timeout;
1610 
1611         /* if we're greater we initiate tx, otherwise we accept */
1612         if (o2nm_this_node() <= o2net_num_from_nn(nn))
1613                 goto out;
1614 
1615         /* watch for racing with tearing a node down */
1616         node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
1617         if (node == NULL) {
1618                 ret = 0;
1619                 goto out;
1620         }
1621 
1622         mynode = o2nm_get_node_by_num(o2nm_this_node());
1623         if (mynode == NULL) {
1624                 ret = 0;
1625                 goto out;
1626         }
1627 
1628         spin_lock(&nn->nn_lock);
1629         /*
1630          * see if we already have one pending or have given up.
1631          * For nn_timeout, it is set when we close the connection
1632          * because of the idle time out. So it means that we have
1633          * at least connected to that node successfully once,
1634          * now try to connect to it again.
1635          */
1636         timeout = atomic_read(&nn->nn_timeout);
1637         stop = (nn->nn_sc ||
1638                 (nn->nn_persistent_error &&
1639                 (nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
1640         spin_unlock(&nn->nn_lock);
1641         if (stop)
1642                 goto out;
1643 
1644         nn->nn_last_connect_attempt = jiffies;
1645 
1646         sc = sc_alloc(node);
1647         if (sc == NULL) {
1648                 mlog(0, "couldn't allocate sc\n");
1649                 ret = -ENOMEM;
1650                 goto out;
1651         }
1652 
1653         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1654         if (ret < 0) {
1655                 mlog(0, "can't create socket: %d\n", ret);
1656                 goto out;
1657         }
1658         sc->sc_sock = sock; /* freed by sc_kref_release */
1659 
1660         sock->sk->sk_allocation = GFP_ATOMIC;
1661 
1662         myaddr.sin_family = AF_INET;
1663         myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
1664         myaddr.sin_port = htons(0); /* any port */
1665 
1666         ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
1667                               sizeof(myaddr));
1668         if (ret) {
1669                 mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
1670                      ret, &mynode->nd_ipv4_address);
1671                 goto out;
1672         }
1673 
1674         ret = o2net_set_nodelay(sc->sc_sock);
1675         if (ret) {
1676                 mlog(ML_ERROR, "setting TCP_NODELAY 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)
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         ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
1841                                sock->sk->sk_protocol, &new_sock);
1842         if (ret)
1843                 goto out;
1844 
1845         new_sock->type = sock->type;
1846         new_sock->ops = sock->ops;
1847         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
1848         if (ret < 0)
1849                 goto out;
1850 
1851         new_sock->sk->sk_allocation = GFP_ATOMIC;
1852 
1853         ret = o2net_set_nodelay(new_sock);
1854         if (ret) {
1855                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1856                 goto out;
1857         }
1858 
1859         slen = sizeof(sin);
1860         ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin,
1861                                        &slen, 1);
1862         if (ret < 0)
1863                 goto out;
1864 
1865         node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
1866         if (node == NULL) {
1867                 printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
1868                        "node at %pI4:%d\n", &sin.sin_addr.s_addr,
1869                        ntohs(sin.sin_port));
1870                 ret = -EINVAL;
1871                 goto out;
1872         }
1873 
1874         if (o2nm_this_node() >= node->nd_num) {
1875                 local_node = o2nm_get_node_by_num(o2nm_this_node());
1876                 if (local_node)
1877                         printk(KERN_NOTICE "o2net: Unexpected connect attempt "
1878                                         "seen at node '%s' (%u, %pI4:%d) from "
1879                                         "node '%s' (%u, %pI4:%d)\n",
1880                                         local_node->nd_name, local_node->nd_num,
1881                                         &(local_node->nd_ipv4_address),
1882                                         ntohs(local_node->nd_ipv4_port),
1883                                         node->nd_name,
1884                                         node->nd_num, &sin.sin_addr.s_addr,
1885                                         ntohs(sin.sin_port));
1886                 ret = -EINVAL;
1887                 goto out;
1888         }
1889 
1890         /* this happens all the time when the other node sees our heartbeat
1891          * and tries to connect before we see their heartbeat */
1892         if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
1893                 mlog(ML_CONN, "attempt to connect from node '%s' at "
1894                      "%pI4:%d but it isn't heartbeating\n",
1895                      node->nd_name, &sin.sin_addr.s_addr,
1896                      ntohs(sin.sin_port));
1897                 ret = -EINVAL;
1898                 goto out;
1899         }
1900 
1901         nn = o2net_nn_from_num(node->nd_num);
1902 
1903         spin_lock(&nn->nn_lock);
1904         if (nn->nn_sc)
1905                 ret = -EBUSY;
1906         else
1907                 ret = 0;
1908         spin_unlock(&nn->nn_lock);
1909         if (ret) {
1910                 printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
1911                        "at %pI4:%d but it already has an open connection\n",
1912                        node->nd_name, &sin.sin_addr.s_addr,
1913                        ntohs(sin.sin_port));
1914                 goto out;
1915         }
1916 
1917         sc = sc_alloc(node);
1918         if (sc == NULL) {
1919                 ret = -ENOMEM;
1920                 goto out;
1921         }
1922 
1923         sc->sc_sock = new_sock;
1924         new_sock = NULL;
1925 
1926         spin_lock(&nn->nn_lock);
1927         atomic_set(&nn->nn_timeout, 0);
1928         o2net_set_nn_state(nn, sc, 0, 0);
1929         spin_unlock(&nn->nn_lock);
1930 
1931         o2net_register_callbacks(sc->sc_sock->sk, sc);
1932         o2net_sc_queue_work(sc, &sc->sc_rx_work);
1933 
1934         o2net_initialize_handshake();
1935         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1936 
1937 out:
1938         if (new_sock)
1939                 sock_release(new_sock);
1940         if (node)
1941                 o2nm_node_put(node);
1942         if (local_node)
1943                 o2nm_node_put(local_node);
1944         if (sc)
1945                 sc_put(sc);
1946         return ret;
1947 }
1948 
1949 static void o2net_accept_many(struct work_struct *work)
1950 {
1951         struct socket *sock = o2net_listen_sock;
1952         while (o2net_accept_one(sock) == 0)
1953                 cond_resched();
1954 }
1955 
1956 static void o2net_listen_data_ready(struct sock *sk, int bytes)
1957 {
1958         void (*ready)(struct sock *sk, int bytes);
1959 
1960         read_lock(&sk->sk_callback_lock);
1961         ready = sk->sk_user_data;
1962         if (ready == NULL) { /* check for teardown race */
1963                 ready = sk->sk_data_ready;
1964                 goto out;
1965         }
1966 
1967         /* ->sk_data_ready is also called for a newly established child socket
1968          * before it has been accepted and the acceptor has set up their
1969          * data_ready.. we only want to queue listen work for our listening
1970          * socket */
1971         if (sk->sk_state == TCP_LISTEN) {
1972                 mlog(ML_TCP, "bytes: %d\n", bytes);
1973                 queue_work(o2net_wq, &o2net_listen_work);
1974         }
1975 
1976 out:
1977         read_unlock(&sk->sk_callback_lock);
1978         ready(sk, bytes);
1979 }
1980 
1981 static int o2net_open_listening_sock(__be32 addr, __be16 port)
1982 {
1983         struct socket *sock = NULL;
1984         int ret;
1985         struct sockaddr_in sin = {
1986                 .sin_family = PF_INET,
1987                 .sin_addr = { .s_addr = addr },
1988                 .sin_port = port,
1989         };
1990 
1991         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1992         if (ret < 0) {
1993                 printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
1994                 goto out;
1995         }
1996 
1997         sock->sk->sk_allocation = GFP_ATOMIC;
1998 
1999         write_lock_bh(&sock->sk->sk_callback_lock);
2000         sock->sk->sk_user_data = sock->sk->sk_data_ready;
2001         sock->sk->sk_data_ready = o2net_listen_data_ready;
2002         write_unlock_bh(&sock->sk->sk_callback_lock);
2003 
2004         o2net_listen_sock = sock;
2005         INIT_WORK(&o2net_listen_work, o2net_accept_many);
2006 
2007         sock->sk->sk_reuse = SK_CAN_REUSE;
2008         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
2009         if (ret < 0) {
2010                 printk(KERN_ERR "o2net: Error %d while binding socket at "
2011                        "%pI4:%u\n", ret, &addr, ntohs(port)); 
2012                 goto out;
2013         }
2014 
2015         ret = sock->ops->listen(sock, 64);
2016         if (ret < 0)
2017                 printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
2018                        ret, &addr, ntohs(port));
2019 
2020 out:
2021         if (ret) {
2022                 o2net_listen_sock = NULL;
2023                 if (sock)
2024                         sock_release(sock);
2025         }
2026         return ret;
2027 }
2028 
2029 /*
2030  * called from node manager when we should bring up our network listening
2031  * socket.  node manager handles all the serialization to only call this
2032  * once and to match it with o2net_stop_listening().  note,
2033  * o2nm_this_node() doesn't work yet as we're being called while it
2034  * is being set up.
2035  */
2036 int o2net_start_listening(struct o2nm_node *node)
2037 {
2038         int ret = 0;
2039 
2040         BUG_ON(o2net_wq != NULL);
2041         BUG_ON(o2net_listen_sock != NULL);
2042 
2043         mlog(ML_KTHREAD, "starting o2net thread...\n");
2044         o2net_wq = create_singlethread_workqueue("o2net");
2045         if (o2net_wq == NULL) {
2046                 mlog(ML_ERROR, "unable to launch o2net thread\n");
2047                 return -ENOMEM; /* ? */
2048         }
2049 
2050         ret = o2net_open_listening_sock(node->nd_ipv4_address,
2051                                         node->nd_ipv4_port);
2052         if (ret) {
2053                 destroy_workqueue(o2net_wq);
2054                 o2net_wq = NULL;
2055         } else
2056                 o2quo_conn_up(node->nd_num);
2057 
2058         return ret;
2059 }
2060 
2061 /* again, o2nm_this_node() doesn't work here as we're involved in
2062  * tearing it down */
2063 void o2net_stop_listening(struct o2nm_node *node)
2064 {
2065         struct socket *sock = o2net_listen_sock;
2066         size_t i;
2067 
2068         BUG_ON(o2net_wq == NULL);
2069         BUG_ON(o2net_listen_sock == NULL);
2070 
2071         /* stop the listening socket from generating work */
2072         write_lock_bh(&sock->sk->sk_callback_lock);
2073         sock->sk->sk_data_ready = sock->sk->sk_user_data;
2074         sock->sk->sk_user_data = NULL;
2075         write_unlock_bh(&sock->sk->sk_callback_lock);
2076 
2077         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2078                 struct o2nm_node *node = o2nm_get_node_by_num(i);
2079                 if (node) {
2080                         o2net_disconnect_node(node);
2081                         o2nm_node_put(node);
2082                 }
2083         }
2084 
2085         /* finish all work and tear down the work queue */
2086         mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
2087         destroy_workqueue(o2net_wq);
2088         o2net_wq = NULL;
2089 
2090         sock_release(o2net_listen_sock);
2091         o2net_listen_sock = NULL;
2092 
2093         o2quo_conn_err(node->nd_num);
2094 }
2095 
2096 /* ------------------------------------------------------------ */
2097 
2098 int o2net_init(void)
2099 {
2100         unsigned long i;
2101 
2102         o2quo_init();
2103 
2104         if (o2net_debugfs_init())
2105                 return -ENOMEM;
2106 
2107         o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
2108         o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2109         o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2110         if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp) {
2111                 kfree(o2net_hand);
2112                 kfree(o2net_keep_req);
2113                 kfree(o2net_keep_resp);
2114                 return -ENOMEM;
2115         }
2116 
2117         o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
2118         o2net_hand->connector_id = cpu_to_be64(1);
2119 
2120         o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
2121         o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
2122 
2123         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2124                 struct o2net_node *nn = o2net_nn_from_num(i);
2125 
2126                 atomic_set(&nn->nn_timeout, 0);
2127                 spin_lock_init(&nn->nn_lock);
2128                 INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
2129                 INIT_DELAYED_WORK(&nn->nn_connect_expired,
2130                                   o2net_connect_expired);
2131                 INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
2132                 /* until we see hb from a node we'll return einval */
2133                 nn->nn_persistent_error = -ENOTCONN;
2134                 init_waitqueue_head(&nn->nn_sc_wq);
2135                 idr_init(&nn->nn_status_idr);
2136                 INIT_LIST_HEAD(&nn->nn_status_list);
2137         }
2138 
2139         return 0;
2140 }
2141 
2142 void o2net_exit(void)
2143 {
2144         o2quo_exit();
2145         kfree(o2net_hand);
2146         kfree(o2net_keep_req);
2147         kfree(o2net_keep_resp);
2148         o2net_debugfs_exit();
2149 }
2150 

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