~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

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 ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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_valid && !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                 if (!o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret))
1020                         continue;
1021                 if (!ret) {
1022                         set_bit(node, map);
1023                         sc_put(sc);
1024                 }
1025         }
1026 }
1027 EXPORT_SYMBOL_GPL(o2net_fill_node_map);
1028 
1029 int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
1030                            size_t caller_veclen, u8 target_node, int *status)
1031 {
1032         int ret = 0;
1033         struct o2net_msg *msg = NULL;
1034         size_t veclen, caller_bytes = 0;
1035         struct kvec *vec = NULL;
1036         struct o2net_sock_container *sc = NULL;
1037         struct o2net_node *nn = o2net_nn_from_num(target_node);
1038         struct o2net_status_wait nsw = {
1039                 .ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
1040         };
1041         struct o2net_send_tracking nst;
1042 
1043         o2net_init_nst(&nst, msg_type, key, current, target_node);
1044 
1045         if (o2net_wq == NULL) {
1046                 mlog(0, "attempt to tx without o2netd running\n");
1047                 ret = -ESRCH;
1048                 goto out;
1049         }
1050 
1051         if (caller_veclen == 0) {
1052                 mlog(0, "bad kvec array length\n");
1053                 ret = -EINVAL;
1054                 goto out;
1055         }
1056 
1057         caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
1058         if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
1059                 mlog(0, "total payload len %zu too large\n", caller_bytes);
1060                 ret = -EINVAL;
1061                 goto out;
1062         }
1063 
1064         if (target_node == o2nm_this_node()) {
1065                 ret = -ELOOP;
1066                 goto out;
1067         }
1068 
1069         o2net_debug_add_nst(&nst);
1070 
1071         o2net_set_nst_sock_time(&nst);
1072 
1073         wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
1074         if (ret)
1075                 goto out;
1076 
1077         o2net_set_nst_sock_container(&nst, sc);
1078 
1079         veclen = caller_veclen + 1;
1080         vec = kmalloc(sizeof(struct kvec) * veclen, GFP_ATOMIC);
1081         if (vec == NULL) {
1082                 mlog(0, "failed to %zu element kvec!\n", veclen);
1083                 ret = -ENOMEM;
1084                 goto out;
1085         }
1086 
1087         msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
1088         if (!msg) {
1089                 mlog(0, "failed to allocate a o2net_msg!\n");
1090                 ret = -ENOMEM;
1091                 goto out;
1092         }
1093 
1094         o2net_init_msg(msg, caller_bytes, msg_type, key);
1095 
1096         vec[0].iov_len = sizeof(struct o2net_msg);
1097         vec[0].iov_base = msg;
1098         memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
1099 
1100         ret = o2net_prep_nsw(nn, &nsw);
1101         if (ret)
1102                 goto out;
1103 
1104         msg->msg_num = cpu_to_be32(nsw.ns_id);
1105         o2net_set_nst_msg_id(&nst, nsw.ns_id);
1106 
1107         o2net_set_nst_send_time(&nst);
1108 
1109         /* finally, convert the message header to network byte-order
1110          * and send */
1111         mutex_lock(&sc->sc_send_lock);
1112         ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
1113                                  sizeof(struct o2net_msg) + caller_bytes);
1114         mutex_unlock(&sc->sc_send_lock);
1115         msglog(msg, "sending returned %d\n", ret);
1116         if (ret < 0) {
1117                 mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
1118                 goto out;
1119         }
1120 
1121         /* wait on other node's handler */
1122         o2net_set_nst_status_time(&nst);
1123         wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
1124 
1125         o2net_update_send_stats(&nst, sc);
1126 
1127         /* Note that we avoid overwriting the callers status return
1128          * variable if a system error was reported on the other
1129          * side. Callers beware. */
1130         ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
1131         if (status && !ret)
1132                 *status = nsw.ns_status;
1133 
1134         mlog(0, "woken, returning system status %d, user status %d\n",
1135              ret, nsw.ns_status);
1136 out:
1137         o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
1138         if (sc)
1139                 sc_put(sc);
1140         kfree(vec);
1141         kfree(msg);
1142         o2net_complete_nsw(nn, &nsw, 0, 0, 0);
1143         return ret;
1144 }
1145 EXPORT_SYMBOL_GPL(o2net_send_message_vec);
1146 
1147 int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
1148                        u8 target_node, int *status)
1149 {
1150         struct kvec vec = {
1151                 .iov_base = data,
1152                 .iov_len = len,
1153         };
1154         return o2net_send_message_vec(msg_type, key, &vec, 1,
1155                                       target_node, status);
1156 }
1157 EXPORT_SYMBOL_GPL(o2net_send_message);
1158 
1159 static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
1160                                    enum o2net_system_error syserr, int err)
1161 {
1162         struct kvec vec = {
1163                 .iov_base = hdr,
1164                 .iov_len = sizeof(struct o2net_msg),
1165         };
1166 
1167         BUG_ON(syserr >= O2NET_ERR_MAX);
1168 
1169         /* leave other fields intact from the incoming message, msg_num
1170          * in particular */
1171         hdr->sys_status = cpu_to_be32(syserr);
1172         hdr->status = cpu_to_be32(err);
1173         hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
1174         hdr->data_len = 0;
1175 
1176         msglog(hdr, "about to send status magic %d\n", err);
1177         /* hdr has been in host byteorder this whole time */
1178         return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
1179 }
1180 
1181 /* this returns -errno if the header was unknown or too large, etc.
1182  * after this is called the buffer us reused for the next message */
1183 static int o2net_process_message(struct o2net_sock_container *sc,
1184                                  struct o2net_msg *hdr)
1185 {
1186         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1187         int ret = 0, handler_status;
1188         enum  o2net_system_error syserr;
1189         struct o2net_msg_handler *nmh = NULL;
1190         void *ret_data = NULL;
1191 
1192         msglog(hdr, "processing message\n");
1193 
1194         o2net_sc_postpone_idle(sc);
1195 
1196         switch(be16_to_cpu(hdr->magic)) {
1197                 case O2NET_MSG_STATUS_MAGIC:
1198                         /* special type for returning message status */
1199                         o2net_complete_nsw(nn, NULL,
1200                                            be32_to_cpu(hdr->msg_num),
1201                                            be32_to_cpu(hdr->sys_status),
1202                                            be32_to_cpu(hdr->status));
1203                         goto out;
1204                 case O2NET_MSG_KEEP_REQ_MAGIC:
1205                         o2net_sendpage(sc, o2net_keep_resp,
1206                                        sizeof(*o2net_keep_resp));
1207                         goto out;
1208                 case O2NET_MSG_KEEP_RESP_MAGIC:
1209                         goto out;
1210                 case O2NET_MSG_MAGIC:
1211                         break;
1212                 default:
1213                         msglog(hdr, "bad magic\n");
1214                         ret = -EINVAL;
1215                         goto out;
1216                         break;
1217         }
1218 
1219         /* find a handler for it */
1220         handler_status = 0;
1221         nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
1222                                 be32_to_cpu(hdr->key));
1223         if (!nmh) {
1224                 mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
1225                      be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
1226                 syserr = O2NET_ERR_NO_HNDLR;
1227                 goto out_respond;
1228         }
1229 
1230         syserr = O2NET_ERR_NONE;
1231 
1232         if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
1233                 syserr = O2NET_ERR_OVERFLOW;
1234 
1235         if (syserr != O2NET_ERR_NONE)
1236                 goto out_respond;
1237 
1238         o2net_set_func_start_time(sc);
1239         sc->sc_msg_key = be32_to_cpu(hdr->key);
1240         sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
1241         handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
1242                                              be16_to_cpu(hdr->data_len),
1243                                         nmh->nh_func_data, &ret_data);
1244         o2net_set_func_stop_time(sc);
1245 
1246         o2net_update_recv_stats(sc);
1247 
1248 out_respond:
1249         /* this destroys the hdr, so don't use it after this */
1250         mutex_lock(&sc->sc_send_lock);
1251         ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
1252                                       handler_status);
1253         mutex_unlock(&sc->sc_send_lock);
1254         hdr = NULL;
1255         mlog(0, "sending handler status %d, syserr %d returned %d\n",
1256              handler_status, syserr, ret);
1257 
1258         if (nmh) {
1259                 BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
1260                 if (nmh->nh_post_func)
1261                         (nmh->nh_post_func)(handler_status, nmh->nh_func_data,
1262                                             ret_data);
1263         }
1264 
1265 out:
1266         if (nmh)
1267                 o2net_handler_put(nmh);
1268         return ret;
1269 }
1270 
1271 static int o2net_check_handshake(struct o2net_sock_container *sc)
1272 {
1273         struct o2net_handshake *hand = page_address(sc->sc_page);
1274         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1275 
1276         if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
1277                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
1278                        "protocol version %llu but %llu is required. "
1279                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1280                        (unsigned long long)be64_to_cpu(hand->protocol_version),
1281                        O2NET_PROTOCOL_VERSION);
1282 
1283                 /* don't bother reconnecting if its the wrong version. */
1284                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1285                 return -1;
1286         }
1287 
1288         /*
1289          * Ensure timeouts are consistent with other nodes, otherwise
1290          * we can end up with one node thinking that the other must be down,
1291          * but isn't. This can ultimately cause corruption.
1292          */
1293         if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
1294                                 o2net_idle_timeout()) {
1295                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
1296                        "idle timeout of %u ms, but we use %u ms locally. "
1297                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1298                        be32_to_cpu(hand->o2net_idle_timeout_ms),
1299                        o2net_idle_timeout());
1300                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1301                 return -1;
1302         }
1303 
1304         if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
1305                         o2net_keepalive_delay()) {
1306                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
1307                        "delay of %u ms, but we use %u ms locally. "
1308                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1309                        be32_to_cpu(hand->o2net_keepalive_delay_ms),
1310                        o2net_keepalive_delay());
1311                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1312                 return -1;
1313         }
1314 
1315         if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
1316                         O2HB_MAX_WRITE_TIMEOUT_MS) {
1317                 printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
1318                        "timeout of %u ms, but we use %u ms locally. "
1319                        "Disconnecting.\n", SC_NODEF_ARGS(sc),
1320                        be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
1321                        O2HB_MAX_WRITE_TIMEOUT_MS);
1322                 o2net_ensure_shutdown(nn, sc, -ENOTCONN);
1323                 return -1;
1324         }
1325 
1326         sc->sc_handshake_ok = 1;
1327 
1328         spin_lock(&nn->nn_lock);
1329         /* set valid and queue the idle timers only if it hasn't been
1330          * shut down already */
1331         if (nn->nn_sc == sc) {
1332                 o2net_sc_reset_idle_timer(sc);
1333                 atomic_set(&nn->nn_timeout, 0);
1334                 o2net_set_nn_state(nn, sc, 1, 0);
1335         }
1336         spin_unlock(&nn->nn_lock);
1337 
1338         /* shift everything up as though it wasn't there */
1339         sc->sc_page_off -= sizeof(struct o2net_handshake);
1340         if (sc->sc_page_off)
1341                 memmove(hand, hand + 1, sc->sc_page_off);
1342 
1343         return 0;
1344 }
1345 
1346 /* this demuxes the queued rx bytes into header or payload bits and calls
1347  * handlers as each full message is read off the socket.  it returns -error,
1348  * == 0 eof, or > 0 for progress made.*/
1349 static int o2net_advance_rx(struct o2net_sock_container *sc)
1350 {
1351         struct o2net_msg *hdr;
1352         int ret = 0;
1353         void *data;
1354         size_t datalen;
1355 
1356         sclog(sc, "receiving\n");
1357         o2net_set_advance_start_time(sc);
1358 
1359         if (unlikely(sc->sc_handshake_ok == 0)) {
1360                 if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
1361                         data = page_address(sc->sc_page) + sc->sc_page_off;
1362                         datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
1363                         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1364                         if (ret > 0)
1365                                 sc->sc_page_off += ret;
1366                 }
1367 
1368                 if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
1369                         o2net_check_handshake(sc);
1370                         if (unlikely(sc->sc_handshake_ok == 0))
1371                                 ret = -EPROTO;
1372                 }
1373                 goto out;
1374         }
1375 
1376         /* do we need more header? */
1377         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1378                 data = page_address(sc->sc_page) + sc->sc_page_off;
1379                 datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
1380                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1381                 if (ret > 0) {
1382                         sc->sc_page_off += ret;
1383                         /* only swab incoming here.. we can
1384                          * only get here once as we cross from
1385                          * being under to over */
1386                         if (sc->sc_page_off == sizeof(struct o2net_msg)) {
1387                                 hdr = page_address(sc->sc_page);
1388                                 if (be16_to_cpu(hdr->data_len) >
1389                                     O2NET_MAX_PAYLOAD_BYTES)
1390                                         ret = -EOVERFLOW;
1391                         }
1392                 }
1393                 if (ret <= 0)
1394                         goto out;
1395         }
1396 
1397         if (sc->sc_page_off < sizeof(struct o2net_msg)) {
1398                 /* oof, still don't have a header */
1399                 goto out;
1400         }
1401 
1402         /* this was swabbed above when we first read it */
1403         hdr = page_address(sc->sc_page);
1404 
1405         msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
1406 
1407         /* do we need more payload? */
1408         if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
1409                 /* need more payload */
1410                 data = page_address(sc->sc_page) + sc->sc_page_off;
1411                 datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
1412                           sc->sc_page_off;
1413                 ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
1414                 if (ret > 0)
1415                         sc->sc_page_off += ret;
1416                 if (ret <= 0)
1417                         goto out;
1418         }
1419 
1420         if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
1421                 /* we can only get here once, the first time we read
1422                  * the payload.. so set ret to progress if the handler
1423                  * works out. after calling this the message is toast */
1424                 ret = o2net_process_message(sc, hdr);
1425                 if (ret == 0)
1426                         ret = 1;
1427                 sc->sc_page_off = 0;
1428         }
1429 
1430 out:
1431         sclog(sc, "ret = %d\n", ret);
1432         o2net_set_advance_stop_time(sc);
1433         return ret;
1434 }
1435 
1436 /* this work func is triggerd by data ready.  it reads until it can read no
1437  * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
1438  * our work the work struct will be marked and we'll be called again. */
1439 static void o2net_rx_until_empty(struct work_struct *work)
1440 {
1441         struct o2net_sock_container *sc =
1442                 container_of(work, struct o2net_sock_container, sc_rx_work);
1443         int ret;
1444 
1445         do {
1446                 ret = o2net_advance_rx(sc);
1447         } while (ret > 0);
1448 
1449         if (ret <= 0 && ret != -EAGAIN) {
1450                 struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1451                 sclog(sc, "saw error %d, closing\n", ret);
1452                 /* not permanent so read failed handshake can retry */
1453                 o2net_ensure_shutdown(nn, sc, 0);
1454         }
1455 
1456         sc_put(sc);
1457 }
1458 
1459 static int o2net_set_nodelay(struct socket *sock)
1460 {
1461         int ret, val = 1;
1462         mm_segment_t oldfs;
1463 
1464         oldfs = get_fs();
1465         set_fs(KERNEL_DS);
1466 
1467         /*
1468          * Dear unsuspecting programmer,
1469          *
1470          * Don't use sock_setsockopt() for SOL_TCP.  It doesn't check its level
1471          * argument and assumes SOL_SOCKET so, say, your TCP_NODELAY will
1472          * silently turn into SO_DEBUG.
1473          *
1474          * Yours,
1475          * Keeper of hilariously fragile interfaces.
1476          */
1477         ret = sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY,
1478                                     (char __user *)&val, sizeof(val));
1479 
1480         set_fs(oldfs);
1481         return ret;
1482 }
1483 
1484 static int o2net_set_usertimeout(struct socket *sock)
1485 {
1486         int user_timeout = O2NET_TCP_USER_TIMEOUT;
1487 
1488         return kernel_setsockopt(sock, SOL_TCP, TCP_USER_TIMEOUT,
1489                                 (char *)&user_timeout, sizeof(user_timeout));
1490 }
1491 
1492 static void o2net_initialize_handshake(void)
1493 {
1494         o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
1495                 O2HB_MAX_WRITE_TIMEOUT_MS);
1496         o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
1497         o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
1498                 o2net_keepalive_delay());
1499         o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
1500                 o2net_reconnect_delay());
1501 }
1502 
1503 /* ------------------------------------------------------------ */
1504 
1505 /* called when a connect completes and after a sock is accepted.  the
1506  * rx path will see the response and mark the sc valid */
1507 static void o2net_sc_connect_completed(struct work_struct *work)
1508 {
1509         struct o2net_sock_container *sc =
1510                 container_of(work, struct o2net_sock_container,
1511                              sc_connect_work);
1512 
1513         mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
1514               (unsigned long long)O2NET_PROTOCOL_VERSION,
1515               (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
1516 
1517         o2net_initialize_handshake();
1518         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1519         sc_put(sc);
1520 }
1521 
1522 /* this is called as a work_struct func. */
1523 static void o2net_sc_send_keep_req(struct work_struct *work)
1524 {
1525         struct o2net_sock_container *sc =
1526                 container_of(work, struct o2net_sock_container,
1527                              sc_keepalive_work.work);
1528 
1529         o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
1530         sc_put(sc);
1531 }
1532 
1533 /* socket shutdown does a del_timer_sync against this as it tears down.
1534  * we can't start this timer until we've got to the point in sc buildup
1535  * where shutdown is going to be involved */
1536 static void o2net_idle_timer(unsigned long data)
1537 {
1538         struct o2net_sock_container *sc = (struct o2net_sock_container *)data;
1539         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1540 #ifdef CONFIG_DEBUG_FS
1541         unsigned long msecs = ktime_to_ms(ktime_get()) -
1542                 ktime_to_ms(sc->sc_tv_timer);
1543 #else
1544         unsigned long msecs = o2net_idle_timeout();
1545 #endif
1546 
1547         printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
1548                "idle for %lu.%lu secs.\n",
1549                SC_NODEF_ARGS(sc), msecs / 1000, msecs % 1000);
1550 
1551         /* idle timerout happen, don't shutdown the connection, but
1552          * make fence decision. Maybe the connection can recover before
1553          * the decision is made.
1554          */
1555         atomic_set(&nn->nn_timeout, 1);
1556         o2quo_conn_err(o2net_num_from_nn(nn));
1557         queue_delayed_work(o2net_wq, &nn->nn_still_up,
1558                         msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
1559 
1560         o2net_sc_reset_idle_timer(sc);
1561 
1562 }
1563 
1564 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
1565 {
1566         o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
1567         o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
1568                       msecs_to_jiffies(o2net_keepalive_delay()));
1569         o2net_set_sock_timer(sc);
1570         mod_timer(&sc->sc_idle_timeout,
1571                jiffies + msecs_to_jiffies(o2net_idle_timeout()));
1572 }
1573 
1574 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
1575 {
1576         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
1577 
1578         /* clear fence decision since the connection recover from timeout*/
1579         if (atomic_read(&nn->nn_timeout)) {
1580                 o2quo_conn_up(o2net_num_from_nn(nn));
1581                 cancel_delayed_work(&nn->nn_still_up);
1582                 atomic_set(&nn->nn_timeout, 0);
1583         }
1584 
1585         /* Only push out an existing timer */
1586         if (timer_pending(&sc->sc_idle_timeout))
1587                 o2net_sc_reset_idle_timer(sc);
1588 }
1589 
1590 /* this work func is kicked whenever a path sets the nn state which doesn't
1591  * have valid set.  This includes seeing hb come up, losing a connection,
1592  * having a connect attempt fail, etc. This centralizes the logic which decides
1593  * if a connect attempt should be made or if we should give up and all future
1594  * transmit attempts should fail */
1595 static void o2net_start_connect(struct work_struct *work)
1596 {
1597         struct o2net_node *nn =
1598                 container_of(work, struct o2net_node, nn_connect_work.work);
1599         struct o2net_sock_container *sc = NULL;
1600         struct o2nm_node *node = NULL, *mynode = NULL;
1601         struct socket *sock = NULL;
1602         struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
1603         int ret = 0, stop;
1604         unsigned int timeout;
1605         unsigned int noio_flag;
1606 
1607         /*
1608          * sock_create allocates the sock with GFP_KERNEL. We must set
1609          * per-process flag PF_MEMALLOC_NOIO so that all allocations done
1610          * by this process are done as if GFP_NOIO was specified. So we
1611          * are not reentering filesystem while doing memory reclaim.
1612          */
1613         noio_flag = memalloc_noio_save();
1614         /* if we're greater we initiate tx, otherwise we accept */
1615         if (o2nm_this_node() <= o2net_num_from_nn(nn))
1616                 goto out;
1617 
1618         /* watch for racing with tearing a node down */
1619         node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
1620         if (node == NULL) {
1621                 ret = 0;
1622                 goto out;
1623         }
1624 
1625         mynode = o2nm_get_node_by_num(o2nm_this_node());
1626         if (mynode == NULL) {
1627                 ret = 0;
1628                 goto out;
1629         }
1630 
1631         spin_lock(&nn->nn_lock);
1632         /*
1633          * see if we already have one pending or have given up.
1634          * For nn_timeout, it is set when we close the connection
1635          * because of the idle time out. So it means that we have
1636          * at least connected to that node successfully once,
1637          * now try to connect to it again.
1638          */
1639         timeout = atomic_read(&nn->nn_timeout);
1640         stop = (nn->nn_sc ||
1641                 (nn->nn_persistent_error &&
1642                 (nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
1643         spin_unlock(&nn->nn_lock);
1644         if (stop)
1645                 goto out;
1646 
1647         nn->nn_last_connect_attempt = jiffies;
1648 
1649         sc = sc_alloc(node);
1650         if (sc == NULL) {
1651                 mlog(0, "couldn't allocate sc\n");
1652                 ret = -ENOMEM;
1653                 goto out;
1654         }
1655 
1656         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1657         if (ret < 0) {
1658                 mlog(0, "can't create socket: %d\n", ret);
1659                 goto out;
1660         }
1661         sc->sc_sock = sock; /* freed by sc_kref_release */
1662 
1663         sock->sk->sk_allocation = GFP_ATOMIC;
1664 
1665         myaddr.sin_family = AF_INET;
1666         myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
1667         myaddr.sin_port = htons(0); /* any port */
1668 
1669         ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
1670                               sizeof(myaddr));
1671         if (ret) {
1672                 mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
1673                      ret, &mynode->nd_ipv4_address);
1674                 goto out;
1675         }
1676 
1677         ret = o2net_set_nodelay(sc->sc_sock);
1678         if (ret) {
1679                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1680                 goto out;
1681         }
1682 
1683         ret = o2net_set_usertimeout(sock);
1684         if (ret) {
1685                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1686                 goto out;
1687         }
1688 
1689         o2net_register_callbacks(sc->sc_sock->sk, sc);
1690 
1691         spin_lock(&nn->nn_lock);
1692         /* handshake completion will set nn->nn_sc_valid */
1693         o2net_set_nn_state(nn, sc, 0, 0);
1694         spin_unlock(&nn->nn_lock);
1695 
1696         remoteaddr.sin_family = AF_INET;
1697         remoteaddr.sin_addr.s_addr = node->nd_ipv4_address;
1698         remoteaddr.sin_port = node->nd_ipv4_port;
1699 
1700         ret = sc->sc_sock->ops->connect(sc->sc_sock,
1701                                         (struct sockaddr *)&remoteaddr,
1702                                         sizeof(remoteaddr),
1703                                         O_NONBLOCK);
1704         if (ret == -EINPROGRESS)
1705                 ret = 0;
1706 
1707 out:
1708         if (ret && sc) {
1709                 printk(KERN_NOTICE "o2net: Connect attempt to " SC_NODEF_FMT
1710                        " failed with errno %d\n", SC_NODEF_ARGS(sc), ret);
1711                 /* 0 err so that another will be queued and attempted
1712                  * from set_nn_state */
1713                 o2net_ensure_shutdown(nn, sc, 0);
1714         }
1715         if (sc)
1716                 sc_put(sc);
1717         if (node)
1718                 o2nm_node_put(node);
1719         if (mynode)
1720                 o2nm_node_put(mynode);
1721 
1722         memalloc_noio_restore(noio_flag);
1723         return;
1724 }
1725 
1726 static void o2net_connect_expired(struct work_struct *work)
1727 {
1728         struct o2net_node *nn =
1729                 container_of(work, struct o2net_node, nn_connect_expired.work);
1730 
1731         spin_lock(&nn->nn_lock);
1732         if (!nn->nn_sc_valid) {
1733                 printk(KERN_NOTICE "o2net: No connection established with "
1734                        "node %u after %u.%u seconds, check network and"
1735                        " cluster configuration.\n",
1736                      o2net_num_from_nn(nn),
1737                      o2net_idle_timeout() / 1000,
1738                      o2net_idle_timeout() % 1000);
1739 
1740                 o2net_set_nn_state(nn, NULL, 0, 0);
1741         }
1742         spin_unlock(&nn->nn_lock);
1743 }
1744 
1745 static void o2net_still_up(struct work_struct *work)
1746 {
1747         struct o2net_node *nn =
1748                 container_of(work, struct o2net_node, nn_still_up.work);
1749 
1750         o2quo_hb_still_up(o2net_num_from_nn(nn));
1751 }
1752 
1753 /* ------------------------------------------------------------ */
1754 
1755 void o2net_disconnect_node(struct o2nm_node *node)
1756 {
1757         struct o2net_node *nn = o2net_nn_from_num(node->nd_num);
1758 
1759         /* don't reconnect until it's heartbeating again */
1760         spin_lock(&nn->nn_lock);
1761         atomic_set(&nn->nn_timeout, 0);
1762         o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
1763         spin_unlock(&nn->nn_lock);
1764 
1765         if (o2net_wq) {
1766                 cancel_delayed_work(&nn->nn_connect_expired);
1767                 cancel_delayed_work(&nn->nn_connect_work);
1768                 cancel_delayed_work(&nn->nn_still_up);
1769                 flush_workqueue(o2net_wq);
1770         }
1771 }
1772 
1773 static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
1774                                   void *data)
1775 {
1776         o2quo_hb_down(node_num);
1777 
1778         if (!node)
1779                 return;
1780 
1781         if (node_num != o2nm_this_node())
1782                 o2net_disconnect_node(node);
1783 
1784         BUG_ON(atomic_read(&o2net_connected_peers) < 0);
1785 }
1786 
1787 static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
1788                                 void *data)
1789 {
1790         struct o2net_node *nn = o2net_nn_from_num(node_num);
1791 
1792         o2quo_hb_up(node_num);
1793 
1794         BUG_ON(!node);
1795 
1796         /* ensure an immediate connect attempt */
1797         nn->nn_last_connect_attempt = jiffies -
1798                 (msecs_to_jiffies(o2net_reconnect_delay()) + 1);
1799 
1800         if (node_num != o2nm_this_node()) {
1801                 /* believe it or not, accept and node hearbeating testing
1802                  * can succeed for this node before we got here.. so
1803                  * only use set_nn_state to clear the persistent error
1804                  * if that hasn't already happened */
1805                 spin_lock(&nn->nn_lock);
1806                 atomic_set(&nn->nn_timeout, 0);
1807                 if (nn->nn_persistent_error)
1808                         o2net_set_nn_state(nn, NULL, 0, 0);
1809                 spin_unlock(&nn->nn_lock);
1810         }
1811 }
1812 
1813 void o2net_unregister_hb_callbacks(void)
1814 {
1815         o2hb_unregister_callback(NULL, &o2net_hb_up);
1816         o2hb_unregister_callback(NULL, &o2net_hb_down);
1817 }
1818 
1819 int o2net_register_hb_callbacks(void)
1820 {
1821         int ret;
1822 
1823         o2hb_setup_callback(&o2net_hb_down, O2HB_NODE_DOWN_CB,
1824                             o2net_hb_node_down_cb, NULL, O2NET_HB_PRI);
1825         o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
1826                             o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
1827 
1828         ret = o2hb_register_callback(NULL, &o2net_hb_up);
1829         if (ret == 0)
1830                 ret = o2hb_register_callback(NULL, &o2net_hb_down);
1831 
1832         if (ret)
1833                 o2net_unregister_hb_callbacks();
1834 
1835         return ret;
1836 }
1837 
1838 /* ------------------------------------------------------------ */
1839 
1840 static int o2net_accept_one(struct socket *sock, int *more)
1841 {
1842         int ret, slen;
1843         struct sockaddr_in sin;
1844         struct socket *new_sock = NULL;
1845         struct o2nm_node *node = NULL;
1846         struct o2nm_node *local_node = NULL;
1847         struct o2net_sock_container *sc = NULL;
1848         struct o2net_node *nn;
1849         unsigned int noio_flag;
1850 
1851         /*
1852          * sock_create_lite allocates the sock with GFP_KERNEL. We must set
1853          * per-process flag PF_MEMALLOC_NOIO so that all allocations done
1854          * by this process are done as if GFP_NOIO was specified. So we
1855          * are not reentering filesystem while doing memory reclaim.
1856          */
1857         noio_flag = memalloc_noio_save();
1858 
1859         BUG_ON(sock == NULL);
1860         *more = 0;
1861         ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
1862                                sock->sk->sk_protocol, &new_sock);
1863         if (ret)
1864                 goto out;
1865 
1866         new_sock->type = sock->type;
1867         new_sock->ops = sock->ops;
1868         ret = sock->ops->accept(sock, new_sock, O_NONBLOCK);
1869         if (ret < 0)
1870                 goto out;
1871 
1872         *more = 1;
1873         new_sock->sk->sk_allocation = GFP_ATOMIC;
1874 
1875         ret = o2net_set_nodelay(new_sock);
1876         if (ret) {
1877                 mlog(ML_ERROR, "setting TCP_NODELAY failed with %d\n", ret);
1878                 goto out;
1879         }
1880 
1881         ret = o2net_set_usertimeout(new_sock);
1882         if (ret) {
1883                 mlog(ML_ERROR, "set TCP_USER_TIMEOUT failed with %d\n", ret);
1884                 goto out;
1885         }
1886 
1887         slen = sizeof(sin);
1888         ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin,
1889                                        &slen, 1);
1890         if (ret < 0)
1891                 goto out;
1892 
1893         node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
1894         if (node == NULL) {
1895                 printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
1896                        "node at %pI4:%d\n", &sin.sin_addr.s_addr,
1897                        ntohs(sin.sin_port));
1898                 ret = -EINVAL;
1899                 goto out;
1900         }
1901 
1902         if (o2nm_this_node() >= node->nd_num) {
1903                 local_node = o2nm_get_node_by_num(o2nm_this_node());
1904                 if (local_node)
1905                         printk(KERN_NOTICE "o2net: Unexpected connect attempt "
1906                                         "seen at node '%s' (%u, %pI4:%d) from "
1907                                         "node '%s' (%u, %pI4:%d)\n",
1908                                         local_node->nd_name, local_node->nd_num,
1909                                         &(local_node->nd_ipv4_address),
1910                                         ntohs(local_node->nd_ipv4_port),
1911                                         node->nd_name,
1912                                         node->nd_num, &sin.sin_addr.s_addr,
1913                                         ntohs(sin.sin_port));
1914                 ret = -EINVAL;
1915                 goto out;
1916         }
1917 
1918         /* this happens all the time when the other node sees our heartbeat
1919          * and tries to connect before we see their heartbeat */
1920         if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
1921                 mlog(ML_CONN, "attempt to connect from node '%s' at "
1922                      "%pI4:%d but it isn't heartbeating\n",
1923                      node->nd_name, &sin.sin_addr.s_addr,
1924                      ntohs(sin.sin_port));
1925                 ret = -EINVAL;
1926                 goto out;
1927         }
1928 
1929         nn = o2net_nn_from_num(node->nd_num);
1930 
1931         spin_lock(&nn->nn_lock);
1932         if (nn->nn_sc)
1933                 ret = -EBUSY;
1934         else
1935                 ret = 0;
1936         spin_unlock(&nn->nn_lock);
1937         if (ret) {
1938                 printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
1939                        "at %pI4:%d but it already has an open connection\n",
1940                        node->nd_name, &sin.sin_addr.s_addr,
1941                        ntohs(sin.sin_port));
1942                 goto out;
1943         }
1944 
1945         sc = sc_alloc(node);
1946         if (sc == NULL) {
1947                 ret = -ENOMEM;
1948                 goto out;
1949         }
1950 
1951         sc->sc_sock = new_sock;
1952         new_sock = NULL;
1953 
1954         spin_lock(&nn->nn_lock);
1955         atomic_set(&nn->nn_timeout, 0);
1956         o2net_set_nn_state(nn, sc, 0, 0);
1957         spin_unlock(&nn->nn_lock);
1958 
1959         o2net_register_callbacks(sc->sc_sock->sk, sc);
1960         o2net_sc_queue_work(sc, &sc->sc_rx_work);
1961 
1962         o2net_initialize_handshake();
1963         o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
1964 
1965 out:
1966         if (new_sock)
1967                 sock_release(new_sock);
1968         if (node)
1969                 o2nm_node_put(node);
1970         if (local_node)
1971                 o2nm_node_put(local_node);
1972         if (sc)
1973                 sc_put(sc);
1974 
1975         memalloc_noio_restore(noio_flag);
1976         return ret;
1977 }
1978 
1979 /*
1980  * This function is invoked in response to one or more
1981  * pending accepts at softIRQ level. We must drain the
1982  * entire que before returning.
1983  */
1984 
1985 static void o2net_accept_many(struct work_struct *work)
1986 {
1987         struct socket *sock = o2net_listen_sock;
1988         int     more;
1989         int     err;
1990 
1991         /*
1992          * It is critical to note that due to interrupt moderation
1993          * at the network driver level, we can't assume to get a
1994          * softIRQ for every single conn since tcp SYN packets
1995          * can arrive back-to-back, and therefore many pending
1996          * accepts may result in just 1 softIRQ. If we terminate
1997          * the o2net_accept_one() loop upon seeing an err, what happens
1998          * to the rest of the conns in the queue? If no new SYN
1999          * arrives for hours, no softIRQ  will be delivered,
2000          * and the connections will just sit in the queue.
2001          */
2002 
2003         for (;;) {
2004                 err = o2net_accept_one(sock, &more);
2005                 if (!more)
2006                         break;
2007                 cond_resched();
2008         }
2009 }
2010 
2011 static void o2net_listen_data_ready(struct sock *sk)
2012 {
2013         void (*ready)(struct sock *sk);
2014 
2015         read_lock(&sk->sk_callback_lock);
2016         ready = sk->sk_user_data;
2017         if (ready == NULL) { /* check for teardown race */
2018                 ready = sk->sk_data_ready;
2019                 goto out;
2020         }
2021 
2022         /* This callback may called twice when a new connection
2023          * is  being established as a child socket inherits everything
2024          * from a parent LISTEN socket, including the data_ready cb of
2025          * the parent. This leads to a hazard. In o2net_accept_one()
2026          * we are still initializing the child socket but have not
2027          * changed the inherited data_ready callback yet when
2028          * data starts arriving.
2029          * We avoid this hazard by checking the state.
2030          * For the listening socket,  the state will be TCP_LISTEN; for the new
2031          * socket, will be  TCP_ESTABLISHED. Also, in this case,
2032          * sk->sk_user_data is not a valid function pointer.
2033          */
2034 
2035         if (sk->sk_state == TCP_LISTEN) {
2036                 queue_work(o2net_wq, &o2net_listen_work);
2037         } else {
2038                 ready = NULL;
2039         }
2040 
2041 out:
2042         read_unlock(&sk->sk_callback_lock);
2043         if (ready != NULL)
2044                 ready(sk);
2045 }
2046 
2047 static int o2net_open_listening_sock(__be32 addr, __be16 port)
2048 {
2049         struct socket *sock = NULL;
2050         int ret;
2051         struct sockaddr_in sin = {
2052                 .sin_family = PF_INET,
2053                 .sin_addr = { .s_addr = addr },
2054                 .sin_port = port,
2055         };
2056 
2057         ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
2058         if (ret < 0) {
2059                 printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
2060                 goto out;
2061         }
2062 
2063         sock->sk->sk_allocation = GFP_ATOMIC;
2064 
2065         write_lock_bh(&sock->sk->sk_callback_lock);
2066         sock->sk->sk_user_data = sock->sk->sk_data_ready;
2067         sock->sk->sk_data_ready = o2net_listen_data_ready;
2068         write_unlock_bh(&sock->sk->sk_callback_lock);
2069 
2070         o2net_listen_sock = sock;
2071         INIT_WORK(&o2net_listen_work, o2net_accept_many);
2072 
2073         sock->sk->sk_reuse = SK_CAN_REUSE;
2074         ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
2075         if (ret < 0) {
2076                 printk(KERN_ERR "o2net: Error %d while binding socket at "
2077                        "%pI4:%u\n", ret, &addr, ntohs(port)); 
2078                 goto out;
2079         }
2080 
2081         ret = sock->ops->listen(sock, 64);
2082         if (ret < 0)
2083                 printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
2084                        ret, &addr, ntohs(port));
2085 
2086 out:
2087         if (ret) {
2088                 o2net_listen_sock = NULL;
2089                 if (sock)
2090                         sock_release(sock);
2091         }
2092         return ret;
2093 }
2094 
2095 /*
2096  * called from node manager when we should bring up our network listening
2097  * socket.  node manager handles all the serialization to only call this
2098  * once and to match it with o2net_stop_listening().  note,
2099  * o2nm_this_node() doesn't work yet as we're being called while it
2100  * is being set up.
2101  */
2102 int o2net_start_listening(struct o2nm_node *node)
2103 {
2104         int ret = 0;
2105 
2106         BUG_ON(o2net_wq != NULL);
2107         BUG_ON(o2net_listen_sock != NULL);
2108 
2109         mlog(ML_KTHREAD, "starting o2net thread...\n");
2110         o2net_wq = create_singlethread_workqueue("o2net");
2111         if (o2net_wq == NULL) {
2112                 mlog(ML_ERROR, "unable to launch o2net thread\n");
2113                 return -ENOMEM; /* ? */
2114         }
2115 
2116         ret = o2net_open_listening_sock(node->nd_ipv4_address,
2117                                         node->nd_ipv4_port);
2118         if (ret) {
2119                 destroy_workqueue(o2net_wq);
2120                 o2net_wq = NULL;
2121         } else
2122                 o2quo_conn_up(node->nd_num);
2123 
2124         return ret;
2125 }
2126 
2127 /* again, o2nm_this_node() doesn't work here as we're involved in
2128  * tearing it down */
2129 void o2net_stop_listening(struct o2nm_node *node)
2130 {
2131         struct socket *sock = o2net_listen_sock;
2132         size_t i;
2133 
2134         BUG_ON(o2net_wq == NULL);
2135         BUG_ON(o2net_listen_sock == NULL);
2136 
2137         /* stop the listening socket from generating work */
2138         write_lock_bh(&sock->sk->sk_callback_lock);
2139         sock->sk->sk_data_ready = sock->sk->sk_user_data;
2140         sock->sk->sk_user_data = NULL;
2141         write_unlock_bh(&sock->sk->sk_callback_lock);
2142 
2143         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2144                 struct o2nm_node *node = o2nm_get_node_by_num(i);
2145                 if (node) {
2146                         o2net_disconnect_node(node);
2147                         o2nm_node_put(node);
2148                 }
2149         }
2150 
2151         /* finish all work and tear down the work queue */
2152         mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
2153         destroy_workqueue(o2net_wq);
2154         o2net_wq = NULL;
2155 
2156         sock_release(o2net_listen_sock);
2157         o2net_listen_sock = NULL;
2158 
2159         o2quo_conn_err(node->nd_num);
2160 }
2161 
2162 /* ------------------------------------------------------------ */
2163 
2164 int o2net_init(void)
2165 {
2166         unsigned long i;
2167 
2168         o2quo_init();
2169 
2170         if (o2net_debugfs_init())
2171                 goto out;
2172 
2173         o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
2174         o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2175         o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
2176         if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp)
2177                 goto out;
2178 
2179         o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
2180         o2net_hand->connector_id = cpu_to_be64(1);
2181 
2182         o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
2183         o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
2184 
2185         for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
2186                 struct o2net_node *nn = o2net_nn_from_num(i);
2187 
2188                 atomic_set(&nn->nn_timeout, 0);
2189                 spin_lock_init(&nn->nn_lock);
2190                 INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
2191                 INIT_DELAYED_WORK(&nn->nn_connect_expired,
2192                                   o2net_connect_expired);
2193                 INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
2194                 /* until we see hb from a node we'll return einval */
2195                 nn->nn_persistent_error = -ENOTCONN;
2196                 init_waitqueue_head(&nn->nn_sc_wq);
2197                 idr_init(&nn->nn_status_idr);
2198                 INIT_LIST_HEAD(&nn->nn_status_list);
2199         }
2200 
2201         return 0;
2202 
2203 out:
2204         kfree(o2net_hand);
2205         kfree(o2net_keep_req);
2206         kfree(o2net_keep_resp);
2207         o2net_debugfs_exit();
2208         o2quo_exit();
2209         return -ENOMEM;
2210 }
2211 
2212 void o2net_exit(void)
2213 {
2214         o2quo_exit();
2215         kfree(o2net_hand);
2216         kfree(o2net_keep_req);
2217         kfree(o2net_keep_resp);
2218         o2net_debugfs_exit();
2219 }
2220 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp