229af8029874b38f780de8a5ca5a19109d7c8e08
[dragonfly.git] / sbin / hammer2 / msg_lnk.c
1 /*
2  * Copyright (c) 2012 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@dragonflybsd.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 /*
35  * LNK_SPAN PROTOCOL SUPPORT FUNCTIONS
36  *
37  * This code supports the LNK_SPAN protocol.  Essentially all PFS's
38  * clients and services rendezvous with the userland hammer2 service and
39  * open LNK_SPAN transactions using a message header linkid of 0,
40  * registering any PFS's they have connectivity to with us.
41  *
42  * --
43  *
44  * Each registration maintains its own open LNK_SPAN message transaction.
45  * The SPANs are collected, aggregated, and retransmitted over available
46  * connections through the maintainance of additional LNK_SPAN message
47  * transactions on each link.
48  *
49  * The msgid for each active LNK_SPAN transaction we receive allows us to
50  * send a message to the target PFS (which might be one of many belonging
51  * to the same cluster), by specifying that msgid as the linkid in any
52  * message we send to the target PFS.
53  *
54  * Similarly the msgid we allocate for any LNK_SPAN transaction we transmit
55  * (and remember we will maintain multiple open LNK_SPAN transactions on
56  * each connection representing the topology span, so every node sees every
57  * other node as a separate open transaction).  So, similarly the msgid for
58  * these active transactions which we initiated can be used by the other
59  * end to route messages through us to another node, ultimately winding up
60  * at the identified hammer2 PFS.  We have to adjust the spanid in the message
61  * header at each hop to be representative of the outgoing LNK_SPAN we
62  * are forwarding the message through.
63  *
64  * --
65  *
66  * If we were to retransmit every LNK_SPAN transaction we receive it would
67  * create a huge mess, so we have to aggregate all received LNK_SPAN
68  * transactions, sort them by the fsid (the cluster) and sub-sort them by
69  * the pfs_fsid (individual nodes in the cluster), and only retransmit
70  * (create outgoing transactions) for a subset of the nearest distance-hops
71  * for each individual node.
72  *
73  * The higher level protocols can then issue transactions to the nodes making
74  * up a cluster to perform all actions required.
75  *
76  * --
77  *
78  * Since this is a large topology and a spanning tree protocol, links can
79  * go up and down all the time.  Any time a link goes down its transaction
80  * is closed.  The transaction has to be closed on both ends before we can
81  * delete (and potentially reuse) the related spanid.  The LNK_SPAN being
82  * closed may have been propagated out to other connections and those related
83  * LNK_SPANs are also closed.  Ultimately all routes via the lost LNK_SPAN
84  * go away, ultimately reaching all sources and all targets.
85  *
86  * Any messages in-transit using a route that goes away will be thrown away.
87  * Open transactions are only tracked at the two end-points.  When a link
88  * failure propagates to an end-point the related open transactions lose
89  * their spanid and are automatically aborted.
90  *
91  * It is important to note that internal route nodes cannot just associate
92  * a lost LNK_SPAN transaction with another route to the same destination.
93  * Message transactions MUST be serialized and MUST be ordered.  All messages
94  * for a transaction must run over the same route.  So if the route used by
95  * an active transaction is lost, the related messages will be fully aborted
96  * and the higher protocol levels will retry as appropriate.
97  *
98  * FULLY ABORTING A ROUTED MESSAGE is handled via link-failure propagation
99  * back to the originator.  Only the originator keeps tracks of a message.
100  * Routers just pass it through.  If a route is lost during transit the
101  * message is simply thrown away.
102  *
103  * It is also important to note that several paths to the same PFS can be
104  * propagated along the same link, which allows concurrency and even
105  * redundancy over several network interfaces or via different routes through
106  * the topology.  Any given transaction will use only a single route but busy
107  * servers will often have hundreds of transactions active simultaniously,
108  * so having multiple active paths through the network topology for A<->B
109  * will improve performance.
110  *
111  * --
112  *
113  * Most protocols consolidate operations rather than simply relaying them.
114  * This is particularly true of LEAF protocols (such as strict HAMMER2
115  * clients), of which there can be millions connecting into the cluster at
116  * various points.  The SPAN protocol is not used for these LEAF elements.
117  *
118  * Instead the primary service they connect to implements a proxy for the
119  * client protocols so the core topology only has to propagate a couple of
120  * LNK_SPANs and not millions.  LNK_SPANs are meant to be used only for
121  * core master nodes and satellite slaves and cache nodes.
122  */
123
124 #include "hammer2.h"
125
126 /*
127  * Maximum spanning tree distance.  This has the practical effect of
128  * stopping tail-chasing closed loops when a feeder span is lost.
129  */
130 #define HAMMER2_SPAN_MAXDIST    16
131
132 /*
133  * RED-BLACK TREE DEFINITIONS
134  *
135  * We need to track:
136  *
137  * (1) shared fsid's (a cluster).
138  * (2) unique fsid's (a node in a cluster) <--- LNK_SPAN transactions.
139  *
140  * We need to aggegate all active LNK_SPANs, aggregate, and create our own
141  * outgoing LNK_SPAN transactions on each of our connections representing
142  * the aggregated state.
143  *
144  * h2span_connect       - list of iocom connections who wish to receive SPAN
145  *                        propagation from other connections.  Might contain
146  *                        a filter string.  Only iocom's with an open
147  *                        LNK_CONN transactions are applicable for SPAN
148  *                        propagation.
149  *
150  * h2span_relay         - List of links relayed (via SPAN).  Essentially
151  *                        each relay structure represents a LNK_SPAN
152  *                        transaction that we initiated, verses h2span_link
153  *                        which is a LNK_SPAN transaction that we received.
154  *
155  * --
156  *
157  * h2span_cluster       - Organizes the shared fsid's.  One structure for
158  *                        each cluster.
159  *
160  * h2span_node          - Organizes the nodes in a cluster.  One structure
161  *                        for each unique {cluster,node}, aka {fsid, pfs_fsid}.
162  *
163  * h2span_link          - Organizes all incoming and outgoing LNK_SPAN message
164  *                        transactions related to a node.
165  *
166  *                        One h2span_link structure for each incoming LNK_SPAN
167  *                        transaction.  Links selected for propagation back
168  *                        out are also where the outgoing LNK_SPAN messages
169  *                        are indexed into (so we can propagate changes).
170  *
171  *                        The h2span_link's use a red-black tree to sort the
172  *                        distance hop metric for the incoming LNK_SPAN.  We
173  *                        then select the top N for outgoing.  When the
174  *                        topology changes the top N may also change and cause
175  *                        new outgoing LNK_SPAN transactions to be opened
176  *                        and less desireable ones to be closed, causing
177  *                        transactional aborts within the message flow in
178  *                        the process.
179  *
180  * Also note            - All outgoing LNK_SPAN message transactions are also
181  *                        entered into a red-black tree for use by the routing
182  *                        function.  This is handled by msg.c in the state
183  *                        code, not here.
184  */
185
186 struct h2span_link;
187 struct h2span_relay;
188 TAILQ_HEAD(h2span_connect_queue, h2span_connect);
189 TAILQ_HEAD(h2span_relay_queue, h2span_relay);
190
191 RB_HEAD(h2span_cluster_tree, h2span_cluster);
192 RB_HEAD(h2span_node_tree, h2span_node);
193 RB_HEAD(h2span_link_tree, h2span_link);
194 RB_HEAD(h2span_relay_tree, h2span_relay);
195
196 /*
197  * Received LNK_CONN transaction enables SPAN protocol over connection.
198  * (may contain filter).
199  */
200 struct h2span_connect {
201         TAILQ_ENTRY(h2span_connect) entry;
202         struct h2span_relay_tree tree;
203         hammer2_state_t *state;
204 };
205
206 /*
207  * All received LNK_SPANs are organized by cluster (pfs_clid),
208  * node (pfs_fsid), and link (received LNK_SPAN transaction).
209  */
210 struct h2span_cluster {
211         RB_ENTRY(h2span_cluster) rbnode;
212         struct h2span_node_tree tree;
213         uuid_t  pfs_clid;               /* shared fsid */
214 };
215
216 struct h2span_node {
217         RB_ENTRY(h2span_node) rbnode;
218         struct h2span_link_tree tree;
219         struct h2span_cluster *cls;
220         uuid_t  pfs_fsid;               /* unique fsid */
221         char label[64];
222 };
223
224 struct h2span_link {
225         RB_ENTRY(h2span_link) rbnode;
226         hammer2_state_t *state;         /* state<->link */
227         struct h2span_node *node;       /* related node */
228         int32_t dist;
229         struct h2span_relay_queue relayq; /* relay out */
230         struct hammer2_router   router;
231 };
232
233 /*
234  * Any LNK_SPAN transactions we receive which are relayed out other
235  * connections utilize this structure to track the LNK_SPAN transaction
236  * we initiate on the other connections, if selected for relay.
237  *
238  * In many respects this is the core of the protocol... actually figuring
239  * out what LNK_SPANs to relay.  The spanid used for relaying is the
240  * address of the 'state' structure, which is why h2span_relay has to
241  * be entered into a RB-TREE based at h2span_connect (so we can look
242  * up the spanid to validate it).
243  */
244 struct h2span_relay {
245         RB_ENTRY(h2span_relay) rbnode;  /* from h2span_connect */
246         TAILQ_ENTRY(h2span_relay) entry; /* from link */
247         struct h2span_connect *conn;
248         hammer2_state_t *state;         /* transmitted LNK_SPAN */
249         struct h2span_link *link;       /* received LNK_SPAN */
250 };
251
252
253 typedef struct h2span_connect h2span_connect_t;
254 typedef struct h2span_cluster h2span_cluster_t;
255 typedef struct h2span_node h2span_node_t;
256 typedef struct h2span_link h2span_link_t;
257 typedef struct h2span_relay h2span_relay_t;
258
259 static
260 int
261 h2span_cluster_cmp(h2span_cluster_t *cls1, h2span_cluster_t *cls2)
262 {
263         return(uuid_compare(&cls1->pfs_clid, &cls2->pfs_clid, NULL));
264 }
265
266 static
267 int
268 h2span_node_cmp(h2span_node_t *node1, h2span_node_t *node2)
269 {
270         return(uuid_compare(&node1->pfs_fsid, &node2->pfs_fsid, NULL));
271 }
272
273 /*
274  * NOTE: Sort/subsort must match h2span_relay_cmp() under any given
275  *       node.
276  */
277 static
278 int
279 h2span_link_cmp(h2span_link_t *link1, h2span_link_t *link2)
280 {
281         if (link1->dist < link2->dist)
282                 return(-1);
283         if (link1->dist > link2->dist)
284                 return(1);
285         if (link1->state->msgid < link2->state->msgid)
286                 return(-1);
287         if (link1->state->msgid > link2->state->msgid)
288                 return(1);
289         return(0);
290 }
291
292 /*
293  * Relay entries are sorted by node, subsorted by distance and link
294  * address (so we can match up the conn->tree relay topology with
295  * a node's link topology).
296  */
297 static
298 int
299 h2span_relay_cmp(h2span_relay_t *relay1, h2span_relay_t *relay2)
300 {
301         h2span_link_t *link1 = relay1->link;
302         h2span_link_t *link2 = relay2->link;
303
304         if ((intptr_t)link1->node < (intptr_t)link2->node)
305                 return(-1);
306         if ((intptr_t)link1->node > (intptr_t)link2->node)
307                 return(1);
308         if (link1->dist < link2->dist)
309                 return(-1);
310         if (link1->dist > link2->dist)
311                 return(1);
312         if (link1->state->msgid < link2->state->msgid)
313                 return(-1);
314         if (link1->state->msgid > link2->state->msgid)
315                 return(1);
316         return(0);
317 }
318
319 RB_PROTOTYPE_STATIC(h2span_cluster_tree, h2span_cluster,
320              rbnode, h2span_cluster_cmp);
321 RB_PROTOTYPE_STATIC(h2span_node_tree, h2span_node,
322              rbnode, h2span_node_cmp);
323 RB_PROTOTYPE_STATIC(h2span_link_tree, h2span_link,
324              rbnode, h2span_link_cmp);
325 RB_PROTOTYPE_STATIC(h2span_relay_tree, h2span_relay,
326              rbnode, h2span_relay_cmp);
327
328 RB_GENERATE_STATIC(h2span_cluster_tree, h2span_cluster,
329              rbnode, h2span_cluster_cmp);
330 RB_GENERATE_STATIC(h2span_node_tree, h2span_node,
331              rbnode, h2span_node_cmp);
332 RB_GENERATE_STATIC(h2span_link_tree, h2span_link,
333              rbnode, h2span_link_cmp);
334 RB_GENERATE_STATIC(h2span_relay_tree, h2span_relay,
335              rbnode, h2span_relay_cmp);
336
337 /*
338  * Global mutex protects cluster_tree lookups.
339  */
340 static pthread_mutex_t cluster_mtx;
341 static struct h2span_cluster_tree cluster_tree = RB_INITIALIZER(cluster_tree);
342 static struct h2span_connect_queue connq = TAILQ_HEAD_INITIALIZER(connq);
343
344 static void hammer2_lnk_span(hammer2_msg_t *msg);
345 static void hammer2_lnk_conn(hammer2_msg_t *msg);
346 static void hammer2_lnk_relay(hammer2_msg_t *msg);
347 static void hammer2_relay_scan(h2span_connect_t *conn, h2span_node_t *node);
348 static void hammer2_relay_delete(h2span_relay_t *relay);
349
350 void
351 hammer2_msg_lnk_signal(hammer2_router_t *router __unused)
352 {
353         pthread_mutex_lock(&cluster_mtx);
354         hammer2_relay_scan(NULL, NULL);
355         pthread_mutex_unlock(&cluster_mtx);
356 }
357
358 /*
359  * Receive a HAMMER2_MSG_PROTO_LNK message.  This only called for
360  * one-way and opening-transactions since state->func will be assigned
361  * in all other cases.
362  */
363 void
364 hammer2_msg_lnk(hammer2_msg_t *msg)
365 {
366         switch(msg->any.head.cmd & HAMMER2_MSGF_BASECMDMASK) {
367         case HAMMER2_LNK_CONN:
368                 hammer2_lnk_conn(msg);
369                 break;
370         case HAMMER2_LNK_SPAN:
371                 hammer2_lnk_span(msg);
372                 break;
373         default:
374                 fprintf(stderr,
375                         "MSG_PROTO_LNK: Unknown msg %08x\n", msg->any.head.cmd);
376                 hammer2_msg_reply(msg, HAMMER2_MSG_ERR_NOSUPP);
377                 /* state invalid after reply */
378                 break;
379         }
380 }
381
382 void
383 hammer2_lnk_conn(hammer2_msg_t *msg)
384 {
385         hammer2_state_t *state = msg->state;
386         h2span_connect_t *conn;
387         h2span_relay_t *relay;
388         char *alloc = NULL;
389
390         pthread_mutex_lock(&cluster_mtx);
391
392         /*
393          * On transaction start we allocate a new h2span_connect and
394          * acknowledge the request, leaving the transaction open.
395          * We then relay priority-selected SPANs.
396          */
397         if (msg->any.head.cmd & HAMMER2_MSGF_CREATE) {
398                 state->func = hammer2_lnk_conn;
399
400                 fprintf(stderr, "LNK_CONN(%08x): %s/%s\n",
401                         (uint32_t)msg->any.head.msgid,
402                         hammer2_uuid_to_str(&msg->any.lnk_conn.pfs_clid,
403                                             &alloc),
404                         msg->any.lnk_conn.label);
405                 free(alloc);
406
407                 conn = hammer2_alloc(sizeof(*conn));
408
409                 RB_INIT(&conn->tree);
410                 conn->state = state;
411                 state->any.conn = conn;
412                 TAILQ_INSERT_TAIL(&connq, conn, entry);
413
414                 hammer2_msg_result(msg, 0);
415
416 #if 0
417                 /*
418                  * Span-synchronize all nodes with the new connection
419                  */
420                 hammer2_relay_scan(conn, NULL);
421 #endif
422                 hammer2_router_signal(msg->router);
423         }
424
425         /*
426          * On transaction terminate we clean out our h2span_connect
427          * and acknowledge the request, closing the transaction.
428          */
429         if (msg->any.head.cmd & HAMMER2_MSGF_DELETE) {
430                 fprintf(stderr, "LNK_CONN: Terminated\n");
431                 conn = state->any.conn;
432                 assert(conn);
433
434                 /*
435                  * Clean out all relays.  This requires terminating each
436                  * relay transaction.
437                  */
438                 while ((relay = RB_ROOT(&conn->tree)) != NULL) {
439                         hammer2_relay_delete(relay);
440                 }
441
442                 /*
443                  * Clean out conn
444                  */
445                 conn->state = NULL;
446                 msg->state->any.conn = NULL;
447                 TAILQ_REMOVE(&connq, conn, entry);
448                 hammer2_free(conn);
449
450                 hammer2_msg_reply(msg, 0);
451                 /* state invalid after reply */
452         }
453         pthread_mutex_unlock(&cluster_mtx);
454 }
455
456 void
457 hammer2_lnk_span(hammer2_msg_t *msg)
458 {
459         hammer2_state_t *state = msg->state;
460         h2span_cluster_t dummy_cls;
461         h2span_node_t dummy_node;
462         h2span_cluster_t *cls;
463         h2span_node_t *node;
464         h2span_link_t *slink;
465         h2span_relay_t *relay;
466         char *alloc = NULL;
467
468         assert((msg->any.head.cmd & HAMMER2_MSGF_REPLY) == 0);
469
470         pthread_mutex_lock(&cluster_mtx);
471
472         /*
473          * On transaction start we initialize the tracking infrastructure
474          */
475         if (msg->any.head.cmd & HAMMER2_MSGF_CREATE) {
476                 assert(state->func == NULL);
477                 state->func = hammer2_lnk_span;
478
479                 msg->any.lnk_span.label[sizeof(msg->any.lnk_span.label)-1] = 0;
480
481                 /*
482                  * Find the cluster
483                  */
484                 dummy_cls.pfs_clid = msg->any.lnk_span.pfs_clid;
485                 cls = RB_FIND(h2span_cluster_tree, &cluster_tree, &dummy_cls);
486                 if (cls == NULL) {
487                         cls = hammer2_alloc(sizeof(*cls));
488                         cls->pfs_clid = msg->any.lnk_span.pfs_clid;
489                         RB_INIT(&cls->tree);
490                         RB_INSERT(h2span_cluster_tree, &cluster_tree, cls);
491                 }
492
493                 /*
494                  * Find the node
495                  */
496                 dummy_node.pfs_fsid = msg->any.lnk_span.pfs_fsid;
497                 node = RB_FIND(h2span_node_tree, &cls->tree, &dummy_node);
498                 if (node == NULL) {
499                         node = hammer2_alloc(sizeof(*node));
500                         node->pfs_fsid = msg->any.lnk_span.pfs_fsid;
501                         node->cls = cls;
502                         RB_INIT(&node->tree);
503                         RB_INSERT(h2span_node_tree, &cls->tree, node);
504                         snprintf(node->label, sizeof(node->label),
505                                  "%s", msg->any.lnk_span.label);
506                 }
507
508                 /*
509                  * Create the link
510                  */
511                 assert(state->any.link == NULL);
512                 slink = hammer2_alloc(sizeof(*slink));
513                 TAILQ_INIT(&slink->relayq);
514                 slink->node = node;
515                 slink->dist = msg->any.lnk_span.dist;
516                 slink->state = state;
517                 state->any.link = slink;
518
519                 /*
520                  * Embedded router structure in link for message forwarding.
521                  */
522                 TAILQ_INIT(&slink->router.txmsgq);
523                 slink->router.iocom = state->iocom;
524                 slink->router.link = slink;
525
526                 RB_INSERT(h2span_link_tree, &node->tree, slink);
527
528                 fprintf(stderr, "LNK_SPAN(thr %p): %p %s/%s dist=%d\n",
529                         msg->router->iocom,
530                         slink,
531                         hammer2_uuid_to_str(&msg->any.lnk_span.pfs_clid,
532                                             &alloc),
533                         msg->any.lnk_span.label,
534                         msg->any.lnk_span.dist);
535                 free(alloc);
536
537 #if 0
538                 hammer2_relay_scan(NULL, node);
539 #endif
540                 hammer2_router_signal(msg->router);
541         }
542
543         /*
544          * On transaction terminate we remove the tracking infrastructure.
545          */
546         if (msg->any.head.cmd & HAMMER2_MSGF_DELETE) {
547                 slink = state->any.link;
548                 assert(slink != NULL);
549                 node = slink->node;
550                 cls = node->cls;
551
552                 fprintf(stderr, "LNK_DELE(thr %p): %p %s/%s dist=%d\n",
553                         msg->router->iocom,
554                         slink,
555                         hammer2_uuid_to_str(&cls->pfs_clid, &alloc),
556                         state->msg->any.lnk_span.label,
557                         state->msg->any.lnk_span.dist);
558                 free(alloc);
559
560                 /*
561                  * Clean out all relays.  This requires terminating each
562                  * relay transaction.
563                  */
564                 while ((relay = TAILQ_FIRST(&slink->relayq)) != NULL) {
565                         hammer2_relay_delete(relay);
566                 }
567
568                 /*
569                  * Clean out the topology
570                  */
571                 RB_REMOVE(h2span_link_tree, &node->tree, slink);
572                 if (RB_EMPTY(&node->tree)) {
573                         RB_REMOVE(h2span_node_tree, &cls->tree, node);
574                         if (RB_EMPTY(&cls->tree)) {
575                                 RB_REMOVE(h2span_cluster_tree,
576                                           &cluster_tree, cls);
577                                 hammer2_free(cls);
578                         }
579                         node->cls = NULL;
580                         hammer2_free(node);
581                         node = NULL;
582                 }
583                 state->any.link = NULL;
584                 slink->state = NULL;
585                 slink->node = NULL;
586                 hammer2_free(slink);
587
588                 /*
589                  * We have to terminate the transaction
590                  */
591                 hammer2_state_reply(state, 0);
592                 /* state invalid after reply */
593
594                 /*
595                  * If the node still exists issue any required updates.  If
596                  * it doesn't then all related relays have already been
597                  * removed and there's nothing left to do.
598                  */
599 #if 0
600                 if (node)
601                         hammer2_relay_scan(NULL, node);
602 #endif
603                 if (node)
604                         hammer2_router_signal(msg->router);
605         }
606
607         pthread_mutex_unlock(&cluster_mtx);
608 }
609
610 /*
611  * Messages received on relay SPANs.  These are open transactions so it is
612  * in fact possible for the other end to close the transaction.
613  *
614  * XXX MPRACE on state structure
615  */
616 static void
617 hammer2_lnk_relay(hammer2_msg_t *msg)
618 {
619         hammer2_state_t *state = msg->state;
620         h2span_relay_t *relay;
621
622         assert(msg->any.head.cmd & HAMMER2_MSGF_REPLY);
623
624         if (msg->any.head.cmd & HAMMER2_MSGF_DELETE) {
625                 pthread_mutex_lock(&cluster_mtx);
626                 if ((relay = state->any.relay) != NULL) {
627                         hammer2_relay_delete(relay);
628                 } else {
629                         hammer2_state_reply(state, 0);
630                 }
631                 pthread_mutex_unlock(&cluster_mtx);
632         }
633 }
634
635 /*
636  * Update relay transactions for SPANs.
637  *
638  * Called with cluster_mtx held.
639  */
640 static void hammer2_relay_scan_specific(h2span_node_t *node,
641                                         h2span_connect_t *conn);
642
643 static void
644 hammer2_relay_scan(h2span_connect_t *conn, h2span_node_t *node)
645 {
646         h2span_cluster_t *cls;
647
648         if (node) {
649                 /*
650                  * Iterate specific node
651                  */
652                 TAILQ_FOREACH(conn, &connq, entry)
653                         hammer2_relay_scan_specific(node, conn);
654         } else {
655                 /*
656                  * Full iteration.
657                  *
658                  * Iterate cluster ids, nodes, and either a specific connection
659                  * or all connections.
660                  */
661                 RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
662                         /*
663                          * Iterate node ids
664                          */
665                         RB_FOREACH(node, h2span_node_tree, &cls->tree) {
666                                 /*
667                                  * Synchronize the node's link (received SPANs)
668                                  * with each connection's relays.
669                                  */
670                                 if (conn) {
671                                         hammer2_relay_scan_specific(node, conn);
672                                 } else {
673                                         TAILQ_FOREACH(conn, &connq, entry) {
674                                             hammer2_relay_scan_specific(node,
675                                                                         conn);
676                                         }
677                                         assert(conn == NULL);
678                                 }
679                         }
680                 }
681         }
682 }
683
684 /*
685  * Update the relay'd SPANs for this (node, conn).
686  *
687  * Iterate links and adjust relays to match.  We only propagate the top link
688  * for now (XXX we want to propagate the top two).
689  *
690  * The hammer2_relay_scan_cmp() function locates the first relay element
691  * for any given node.  The relay elements will be sub-sorted by dist.
692  */
693 struct relay_scan_info {
694         h2span_node_t *node;
695         h2span_relay_t *relay;
696 };
697
698 static int
699 hammer2_relay_scan_cmp(h2span_relay_t *relay, void *arg)
700 {
701         struct relay_scan_info *info = arg;
702
703         if ((intptr_t)relay->link->node < (intptr_t)info->node)
704                 return(-1);
705         if ((intptr_t)relay->link->node > (intptr_t)info->node)
706                 return(1);
707         return(0);
708 }
709
710 static int
711 hammer2_relay_scan_callback(h2span_relay_t *relay, void *arg)
712 {
713         struct relay_scan_info *info = arg;
714
715         info->relay = relay;
716         return(-1);
717 }
718
719 static void
720 hammer2_relay_scan_specific(h2span_node_t *node, h2span_connect_t *conn)
721 {
722         struct relay_scan_info info;
723         h2span_relay_t *relay;
724         h2span_relay_t *next_relay;
725         h2span_link_t *slink;
726         int count = 2;
727
728         info.node = node;
729         info.relay = NULL;
730
731         /*
732          * Locate the first related relay for the node on this connection.
733          * relay will be NULL if there were none.
734          */
735         RB_SCAN(h2span_relay_tree, &conn->tree,
736                 hammer2_relay_scan_cmp, hammer2_relay_scan_callback, &info);
737         relay = info.relay;
738         info.relay = NULL;
739         if (relay)
740                 assert(relay->link->node == node);
741
742         if (DebugOpt > 8)
743                 fprintf(stderr, "relay scan for connection %p\n", conn);
744
745         /*
746          * Iterate the node's links (received SPANs) in distance order,
747          * lowest (best) dist first.
748          */
749         /* fprintf(stderr, "LOOP\n"); */
750         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
751                 /*
752                 fprintf(stderr, "SLINK %p RELAY %p(%p)\n",
753                         slink, relay, relay ? relay->link : NULL);
754                 */
755                 /*
756                  * PROPAGATE THE BEST LINKS OVER THE SPECIFIED CONNECTION.
757                  *
758                  * Track relays while iterating the best links and construct
759                  * missing relays when necessary.
760                  *
761                  * (If some prior better link was removed it would have also
762                  *  removed the relay, so the relay can only match exactly or
763                  *  be worse).
764                  */
765                 if (relay && relay->link == slink) {
766                         /*
767                          * Match, relay already in-place, get the next
768                          * relay to match against the next slink.
769                          */
770                         relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
771                         if (--count == 0)
772                                 break;
773                 } else if (slink->dist > HAMMER2_SPAN_MAXDIST) {
774                         /*
775                          * No match but span distance is too great,
776                          * do not relay.  This prevents endless closed
777                          * loops with ever-incrementing distances when
778                          * the seed span is lost in the graph.
779                          *
780                          * All later spans will also be too far away so
781                          * we can break out of the loop.
782                          */
783                         break;
784                 } else {
785                         /*
786                          * No match, distance is ok, construct a new relay.
787                          * (slink is better than relay).
788                          */
789                         hammer2_msg_t *msg;
790
791                         assert(relay == NULL ||
792                                relay->link->node != slink->node ||
793                                relay->link->dist >= slink->dist);
794                         relay = hammer2_alloc(sizeof(*relay));
795                         relay->conn = conn;
796                         relay->link = slink;
797
798                         msg = hammer2_msg_alloc(&conn->state->iocom->router, 0,
799                                                 HAMMER2_LNK_SPAN |
800                                                 HAMMER2_MSGF_CREATE,
801                                                 hammer2_lnk_relay, relay);
802                         relay->state = msg->state;
803                         msg->any.lnk_span = slink->state->msg->any.lnk_span;
804                         msg->any.lnk_span.dist = slink->dist + 1;
805
806                         RB_INSERT(h2span_relay_tree, &conn->tree, relay);
807                         TAILQ_INSERT_TAIL(&slink->relayq, relay, entry);
808
809                         hammer2_msg_write(msg);
810
811                         fprintf(stderr,
812                                 "RELAY SPAN %p RELAY %p ON CLS=%p NODE=%p DIST=%d "
813                                 "FD %d state %p\n",
814                                 slink,
815                                 relay,
816                                 node->cls, node, slink->dist,
817                                 conn->state->iocom->sock_fd, relay->state);
818
819                         /*
820                          * Match (created new relay), get the next relay to
821                          * match against the next slink.
822                          */
823                         relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
824                         if (--count == 0)
825                                 break;
826                 }
827         }
828
829         /*
830          * Any remaining relay's belonging to this connection which match
831          * the node are in excess of the current aggregate spanning state
832          * and should be removed.
833          */
834         while (relay && relay->link->node == node) {
835                 next_relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
836                 hammer2_relay_delete(relay);
837                 relay = next_relay;
838         }
839 }
840
841 static
842 void
843 hammer2_relay_delete(h2span_relay_t *relay)
844 {
845         fprintf(stderr,
846                 "RELAY DELETE %p RELAY %p ON CLS=%p NODE=%p DIST=%d FD %d STATE %p\n",
847                 relay->link,
848                 relay,
849                 relay->link->node->cls, relay->link->node,
850                 relay->link->dist,
851                 relay->conn->state->iocom->sock_fd, relay->state);
852
853         RB_REMOVE(h2span_relay_tree, &relay->conn->tree, relay);
854         TAILQ_REMOVE(&relay->link->relayq, relay, entry);
855
856         if (relay->state) {
857                 relay->state->any.relay = NULL;
858                 hammer2_state_reply(relay->state, 0);
859                 /* state invalid after reply */
860                 relay->state = NULL;
861         }
862         relay->conn = NULL;
863         relay->link = NULL;
864         hammer2_free(relay);
865 }
866
867 /************************************************************************
868  *                              ROUTER                                  *
869  ************************************************************************
870  *
871  * Provides route functions to msg.c
872  */
873
874 #if 0
875 /*
876  * Acquire a persistent router structure given the cluster and node ids.
877  * Messages can be transacted via this structure while held.  If the route
878  * is lost messages will return failure.
879  */
880 hammer2_router_t *
881 hammer2_router_get(uuid_t *pfs_clid, uuid_t *pfs_fsid)
882 {
883 }
884
885 /*
886  * Release previously acquired router.
887  */
888 void
889 hammer2_router_put(hammer2_router_t *router)
890 {
891 }
892 #endif
893
894 /*
895  * Dumps the spanning tree
896  */
897 void
898 shell_tree(hammer2_router_t *router, char *cmdbuf __unused)
899 {
900         h2span_cluster_t *cls;
901         h2span_node_t *node;
902         h2span_link_t *slink;
903         char *uustr = NULL;
904
905         pthread_mutex_lock(&cluster_mtx);
906         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
907                 router_printf(router, "Cluster %s\n",
908                              hammer2_uuid_to_str(&cls->pfs_clid, &uustr));
909                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
910                         router_printf(router, "    Node %s (%s)\n",
911                                  hammer2_uuid_to_str(&node->pfs_fsid, &uustr),
912                                  node->label);
913                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
914                                 router_printf(router, "\tLink dist=%d via %d\n",
915                                              slink->dist,
916                                              slink->state->iocom->sock_fd);
917                         }
918                 }
919         }
920         pthread_mutex_unlock(&cluster_mtx);
921         if (uustr)
922                 free(uustr);
923 #if 0
924         TAILQ_FOREACH(conn, &connq, entry) {
925         }
926 #endif
927 }