lib/libdmsg/msg_lnk.c

   1 /*
   2  * Copyright (c) 2012-2014 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 - Please see sys/dmsg.h for an
  36  * involved explanation of the protocol.
  37  */
  38
  39 #include "dmsg_local.h"
  40
  41 /*
  42  * Maximum spanning tree distance.  This has the practical effect of
  43  * stopping tail-chasing closed loops when a feeder span is lost.
  44  */
  45 #define DMSG_SPAN_MAXDIST       16
  46
  47 /*
  48  * RED-BLACK TREE DEFINITIONS
  49  *
  50  * We need to track:
  51  *
  52  * (1) shared fsid's (a cluster).
  53  * (2) unique fsid's (a node in a cluster) <--- LNK_SPAN transactions.
  54  *
  55  * We need to aggegate all active LNK_SPANs, aggregate, and create our own
  56  * outgoing LNK_SPAN transactions on each of our connections representing
  57  * the aggregated state.
  58  *
  59  * h2span_conn          - list of iocom connections who wish to receive SPAN
  60  *                        propagation from other connections.  Might contain
  61  *                        a filter string.  Only iocom's with an open
  62  *                        LNK_CONN transactions are applicable for SPAN
  63  *                        propagation.
  64  *
  65  * h2span_relay         - List of links relayed (via SPAN).  Essentially
  66  *                        each relay structure represents a LNK_SPAN
  67  *                        transaction that we initiated, verses h2span_link
  68  *                        which is a LNK_SPAN transaction that we received.
  69  *
  70  * --
  71  *
  72  * h2span_cluster       - Organizes the shared fsid's.  One structure for
  73  *                        each cluster.
  74  *
  75  * h2span_node          - Organizes the nodes in a cluster.  One structure
  76  *                        for each unique {cluster,node}, aka {fsid, pfs_fsid}.
  77  *
  78  * h2span_link          - Organizes all incoming and outgoing LNK_SPAN message
  79  *                        transactions related to a node.
  80  *
  81  *                        One h2span_link structure for each incoming LNK_SPAN
  82  *                        transaction.  Links selected for propagation back
  83  *                        out are also where the outgoing LNK_SPAN messages
  84  *                        are indexed into (so we can propagate changes).
  85  *
  86  *                        The h2span_link's use a red-black tree to sort the
  87  *                        distance hop metric for the incoming LNK_SPAN.  We
  88  *                        then select the top N for outgoing.  When the
  89  *                        topology changes the top N may also change and cause
  90  *                        new outgoing LNK_SPAN transactions to be opened
  91  *                        and less desireable ones to be closed, causing
  92  *                        transactional aborts within the message flow in
  93  *                        the process.
  94  *
  95  * Also note            - All outgoing LNK_SPAN message transactions are also
  96  *                        entered into a red-black tree for use by the routing
  97  *                        function.  This is handled by msg.c in the state
  98  *                        code, not here.
  99  */
 100
 101 struct h2span_link;
 102 struct h2span_relay;
 103 TAILQ_HEAD(h2span_conn_queue, h2span_conn);
 104 TAILQ_HEAD(h2span_relay_queue, h2span_relay);
 105
 106 RB_HEAD(h2span_cluster_tree, h2span_cluster);
 107 RB_HEAD(h2span_node_tree, h2span_node);
 108 RB_HEAD(h2span_link_tree, h2span_link);
 109 RB_HEAD(h2span_relay_tree, h2span_relay);
 110 uint32_t DMsgRNSS;
 111
 112 /*
 113  * Received LNK_CONN transaction enables SPAN protocol over connection.
 114  * (may contain filter).  Typically one for each mount and several may
 115  * share the same media.
 116  */
 117 struct h2span_conn {
 118         TAILQ_ENTRY(h2span_conn) entry;
 119         struct h2span_relay_tree tree;
 120         dmsg_state_t *state;
 121         dmsg_lnk_conn_t lnk_conn;
 122 };
 123
 124 /*
 125  * All received LNK_SPANs are organized by cluster (pfs_clid),
 126  * node (pfs_fsid), and link (received LNK_SPAN transaction).
 127  */
 128 struct h2span_cluster {
 129         RB_ENTRY(h2span_cluster) rbnode;
 130         struct h2span_node_tree tree;
 131         uuid_t  pfs_clid;               /* shared fsid */
 132         uint8_t peer_type;
 133         char    cl_label[128];          /* cluster label (typ PEER_BLOCK) */
 134         int     refs;                   /* prevents destruction */
 135 };
 136
 137 struct h2span_node {
 138         RB_ENTRY(h2span_node) rbnode;
 139         struct h2span_link_tree tree;
 140         struct h2span_cluster *cls;
 141         uint8_t pfs_type;
 142         uuid_t  pfs_fsid;               /* unique fsid */
 143         char    fs_label[128];          /* fs label (typ PEER_HAMMER2) */
 144         void    *opaque;
 145 };
 146
 147 struct h2span_link {
 148         RB_ENTRY(h2span_link) rbnode;
 149         dmsg_state_t    *state;         /* state<->link */
 150         struct h2span_node *node;       /* related node */
 151         struct h2span_relay_queue relayq; /* relay out */
 152         dmsg_lnk_span_t lnk_span;
 153 };
 154
 155 /*
 156  * Any LNK_SPAN transactions we receive which are relayed out other
 157  * connections utilize this structure to track the LNK_SPAN transactions
 158  * we initiate (relay out) on other connections.  We only relay out
 159  * LNK_SPANs on connections we have an open CONN transaction for.
 160  *
 161  * The relay structure points to the outgoing LNK_SPAN trans (out_state)
 162  * and to the incoming LNK_SPAN transaction (in_state).  The relay
 163  * structure holds refs on the related states.
 164  *
 165  * In many respects this is the core of the protocol... actually figuring
 166  * out what LNK_SPANs to relay.  The spanid used for relaying is the
 167  * address of the 'state' structure, which is why h2span_relay has to
 168  * be entered into a RB-TREE based at h2span_conn (so we can look
 169  * up the spanid to validate it).
 170  */
 171 struct h2span_relay {
 172         TAILQ_ENTRY(h2span_relay) entry;        /* from link */
 173         RB_ENTRY(h2span_relay) rbnode;          /* from h2span_conn */
 174         struct h2span_conn      *conn;          /* related CONN transaction */
 175         dmsg_state_t            *source_rt;     /* h2span_link state */
 176         dmsg_state_t            *target_rt;     /* h2span_relay state */
 177 };
 178
 179 typedef struct h2span_conn h2span_conn_t;
 180 typedef struct h2span_cluster h2span_cluster_t;
 181 typedef struct h2span_node h2span_node_t;
 182 typedef struct h2span_link h2span_link_t;
 183 typedef struct h2span_relay h2span_relay_t;
 184
 185 #define dmsg_termstr(array)     _dmsg_termstr((array), sizeof(array))
 186
 187 static h2span_relay_t *dmsg_generate_relay(h2span_conn_t *conn,
 188                                         h2span_link_t *slink);
 189 static uint32_t dmsg_rnss(void);
 190
 191 static __inline
 192 void
 193 _dmsg_termstr(char *base, size_t size)
 194 {
 195         base[size-1] = 0;
 196 }
 197
 198 /*
 199  * Cluster peer_type, uuid, AND label must match for a match
 200  */
 201 static
 202 int
 203 h2span_cluster_cmp(h2span_cluster_t *cls1, h2span_cluster_t *cls2)
 204 {
 205         int r;
 206
 207         if (cls1->peer_type < cls2->peer_type)
 208                 return(-1);
 209         if (cls1->peer_type > cls2->peer_type)
 210                 return(1);
 211         r = uuid_compare(&cls1->pfs_clid, &cls2->pfs_clid, NULL);
 212         if (r == 0)
 213                 r = strcmp(cls1->cl_label, cls2->cl_label);
 214
 215         return r;
 216 }
 217
 218 /*
 219  * Match against fs_label/pfs_fsid.  Together these two items represent a
 220  * unique node.  In most cases the primary differentiator is pfs_fsid but
 221  * we also string-match fs_label.
 222  */
 223 static
 224 int
 225 h2span_node_cmp(h2span_node_t *node1, h2span_node_t *node2)
 226 {
 227         int r;
 228
 229         r = strcmp(node1->fs_label, node2->fs_label);
 230         if (r == 0)
 231                 r = uuid_compare(&node1->pfs_fsid, &node2->pfs_fsid, NULL);
 232         return (r);
 233 }
 234
 235 /*
 236  * Sort/subsort must match h2span_relay_cmp() under any given node
 237  * to make the aggregation algorithm easier, so the best links are
 238  * in the same sorted order as the best relays.
 239  *
 240  * NOTE: We cannot use link*->state->msgid because this msgid is created
 241  *       by each remote host and thus might wind up being the same.
 242  */
 243 static
 244 int
 245 h2span_link_cmp(h2span_link_t *link1, h2span_link_t *link2)
 246 {
 247         if (link1->lnk_span.dist < link2->lnk_span.dist)
 248                 return(-1);
 249         if (link1->lnk_span.dist > link2->lnk_span.dist)
 250                 return(1);
 251         if (link1->lnk_span.rnss < link2->lnk_span.rnss)
 252                 return(-1);
 253         if (link1->lnk_span.rnss > link2->lnk_span.rnss)
 254                 return(1);
 255 #if 1
 256         if ((uintptr_t)link1->state < (uintptr_t)link2->state)
 257                 return(-1);
 258         if ((uintptr_t)link1->state > (uintptr_t)link2->state)
 259                 return(1);
 260 #else
 261         if (link1->state->msgid < link2->state->msgid)
 262                 return(-1);
 263         if (link1->state->msgid > link2->state->msgid)
 264                 return(1);
 265 #endif
 266         return(0);
 267 }
 268
 269 /*
 270  * Relay entries are sorted by node, subsorted by distance and link
 271  * address (so we can match up the conn->tree relay topology with
 272  * a node's link topology).
 273  */
 274 static
 275 int
 276 h2span_relay_cmp(h2span_relay_t *relay1, h2span_relay_t *relay2)
 277 {
 278         h2span_link_t *link1 = relay1->source_rt->any.link;
 279         h2span_link_t *link2 = relay2->source_rt->any.link;
 280
 281         if ((intptr_t)link1->node < (intptr_t)link2->node)
 282                 return(-1);
 283         if ((intptr_t)link1->node > (intptr_t)link2->node)
 284                 return(1);
 285         if (link1->lnk_span.dist < link2->lnk_span.dist)
 286                 return(-1);
 287         if (link1->lnk_span.dist > link2->lnk_span.dist)
 288                 return(1);
 289         if (link1->lnk_span.rnss < link2->lnk_span.rnss)
 290                 return(-1);
 291         if (link1->lnk_span.rnss > link2->lnk_span.rnss)
 292                 return(1);
 293 #if 1
 294         if ((uintptr_t)link1->state < (uintptr_t)link2->state)
 295                 return(-1);
 296         if ((uintptr_t)link1->state > (uintptr_t)link2->state)
 297                 return(1);
 298 #else
 299         if (link1->state->msgid < link2->state->msgid)
 300                 return(-1);
 301         if (link1->state->msgid > link2->state->msgid)
 302                 return(1);
 303 #endif
 304         return(0);
 305 }
 306
 307 RB_PROTOTYPE_STATIC(h2span_cluster_tree, h2span_cluster,
 308              rbnode, h2span_cluster_cmp);
 309 RB_PROTOTYPE_STATIC(h2span_node_tree, h2span_node,
 310              rbnode, h2span_node_cmp);
 311 RB_PROTOTYPE_STATIC(h2span_link_tree, h2span_link,
 312              rbnode, h2span_link_cmp);
 313 RB_PROTOTYPE_STATIC(h2span_relay_tree, h2span_relay,
 314              rbnode, h2span_relay_cmp);
 315
 316 RB_GENERATE_STATIC(h2span_cluster_tree, h2span_cluster,
 317              rbnode, h2span_cluster_cmp);
 318 RB_GENERATE_STATIC(h2span_node_tree, h2span_node,
 319              rbnode, h2span_node_cmp);
 320 RB_GENERATE_STATIC(h2span_link_tree, h2span_link,
 321              rbnode, h2span_link_cmp);
 322 RB_GENERATE_STATIC(h2span_relay_tree, h2span_relay,
 323              rbnode, h2span_relay_cmp);
 324
 325 /*
 326  * Global mutex protects cluster_tree lookups, connq, mediaq.
 327  */
 328 static pthread_mutex_t cluster_mtx;
 329 static struct h2span_cluster_tree cluster_tree = RB_INITIALIZER(cluster_tree);
 330 static struct h2span_conn_queue connq = TAILQ_HEAD_INITIALIZER(connq);
 331 static struct dmsg_media_queue mediaq = TAILQ_HEAD_INITIALIZER(mediaq);
 332
 333 static void dmsg_lnk_span(dmsg_msg_t *msg);
 334 static void dmsg_lnk_conn(dmsg_msg_t *msg);
 335 static void dmsg_lnk_relay(dmsg_msg_t *msg);
 336 static void dmsg_relay_scan(h2span_conn_t *conn, h2span_node_t *node);
 337 static void dmsg_relay_delete(h2span_relay_t *relay);
 338
 339 void
 340 dmsg_msg_lnk_signal(dmsg_iocom_t *iocom __unused)
 341 {
 342         pthread_mutex_lock(&cluster_mtx);
 343         dmsg_relay_scan(NULL, NULL);
 344         pthread_mutex_unlock(&cluster_mtx);
 345 }
 346
 347 /*
 348  * DMSG_PROTO_LNK - Generic DMSG_PROTO_LNK.
 349  *            (incoming iocom lock not held)
 350  *
 351  * This function is typically called for one-way and opening-transactions
 352  * since state->func is assigned after that, but it will also be called
 353  * if no state->func is assigned on transaction-open.
 354  */
 355 void
 356 dmsg_msg_lnk(dmsg_msg_t *msg)
 357 {
 358         dmsg_iocom_t *iocom = msg->state->iocom;
 359
 360         switch(msg->tcmd & DMSGF_BASECMDMASK) {
 361         case DMSG_LNK_CONN:
 362                 dmsg_lnk_conn(msg);
 363                 break;
 364         case DMSG_LNK_SPAN:
 365                 dmsg_lnk_span(msg);
 366                 break;
 367         default:
 368                 iocom->usrmsg_callback(msg, 1);
 369                 /* state invalid after reply */
 370                 break;
 371         }
 372 }
 373
 374 /*
 375  * LNK_CONN - iocom identify message reception.
 376  *            (incoming iocom lock not held)
 377  *
 378  * Remote node identifies itself to us, sets up a SPAN filter, and gives us
 379  * the ok to start transmitting SPANs.
 380  */
 381 void
 382 dmsg_lnk_conn(dmsg_msg_t *msg)
 383 {
 384         dmsg_state_t *state = msg->state;
 385         dmsg_iocom_t *iocom = state->iocom;
 386         dmsg_media_t *media;
 387         h2span_conn_t *conn;
 388         h2span_relay_t *relay;
 389         char *alloc = NULL;
 390
 391         pthread_mutex_lock(&cluster_mtx);
 392
 393         fprintf(stderr,
 394                 "dmsg_lnk_conn: msg %p cmd %08x state %p "
 395                 "txcmd %08x rxcmd %08x\n",
 396                 msg, msg->any.head.cmd, state,
 397                 state->txcmd, state->rxcmd);
 398
 399         switch(msg->any.head.cmd & DMSGF_TRANSMASK) {
 400         case DMSG_LNK_CONN | DMSGF_CREATE:
 401         case DMSG_LNK_CONN | DMSGF_CREATE | DMSGF_DELETE:
 402                 /*
 403                  * On transaction start we allocate a new h2span_conn and
 404                  * acknowledge the request, leaving the transaction open.
 405                  * We then relay priority-selected SPANs.
 406                  */
 407                 fprintf(stderr, "LNK_CONN(%08x): %s/%s/%s\n",
 408                         (uint32_t)msg->any.head.msgid,
 409                         dmsg_uuid_to_str(&msg->any.lnk_conn.pfs_clid,
 410                                             &alloc),
 411                         msg->any.lnk_conn.cl_label,
 412                         msg->any.lnk_conn.fs_label);
 413                 free(alloc);
 414
 415                 conn = dmsg_alloc(sizeof(*conn));
 416                 assert(state->iocom->conn == NULL);
 417
 418                 RB_INIT(&conn->tree);
 419                 state->iocom->conn = conn;      /* XXX only one */
 420                 state->iocom->conn_msgid = state->msgid;
 421                 conn->state = state;
 422                 state->func = dmsg_lnk_conn;
 423                 state->any.conn = conn;
 424                 TAILQ_INSERT_TAIL(&connq, conn, entry);
 425                 conn->lnk_conn = msg->any.lnk_conn;
 426
 427                 /*
 428                  * Set up media
 429                  */
 430                 TAILQ_FOREACH(media, &mediaq, entry) {
 431                         if (uuid_compare(&msg->any.lnk_conn.mediaid,
 432                                          &media->mediaid, NULL) == 0) {
 433                                 break;
 434                         }
 435                 }
 436                 if (media == NULL) {
 437                         media = dmsg_alloc(sizeof(*media));
 438                         media->mediaid = msg->any.lnk_conn.mediaid;
 439                         TAILQ_INSERT_TAIL(&mediaq, media, entry);
 440                 }
 441                 state->media = media;
 442                 ++media->refs;
 443
 444                 if ((msg->any.head.cmd & DMSGF_DELETE) == 0) {
 445                         iocom->usrmsg_callback(msg, 0);
 446                         dmsg_msg_result(msg, 0);
 447                         dmsg_iocom_signal(iocom);
 448                         break;
 449                 }
 450                 /* FALL THROUGH */
 451         case DMSG_LNK_CONN | DMSGF_DELETE:
 452         case DMSG_LNK_ERROR | DMSGF_DELETE:
 453                 /*
 454                  * On transaction terminate we clean out our h2span_conn
 455                  * and acknowledge the request, closing the transaction.
 456                  */
 457                 fprintf(stderr, "LNK_CONN: Terminated\n");
 458                 conn = state->any.conn;
 459                 assert(conn);
 460
 461                 /*
 462                  * Adjust media refs
 463                  *
 464                  * Callback will clean out media config / user-opaque state
 465                  */
 466                 media = state->media;
 467                 --media->refs;
 468                 if (media->refs == 0) {
 469                         fprintf(stderr, "Media shutdown\n");
 470                         TAILQ_REMOVE(&mediaq, media, entry);
 471                         pthread_mutex_unlock(&cluster_mtx);
 472                         iocom->usrmsg_callback(msg, 0);
 473                         pthread_mutex_lock(&cluster_mtx);
 474                         dmsg_free(media);
 475                 }
 476                 state->media = NULL;
 477
 478                 /*
 479                  * Clean out all relays.  This requires terminating each
 480                  * relay transaction.
 481                  */
 482                 while ((relay = RB_ROOT(&conn->tree)) != NULL) {
 483                         dmsg_relay_delete(relay);
 484                 }
 485
 486                 /*
 487                  * Clean out conn
 488                  */
 489                 conn->state = NULL;
 490                 msg->state->any.conn = NULL;
 491                 msg->state->iocom->conn = NULL;
 492                 TAILQ_REMOVE(&connq, conn, entry);
 493                 dmsg_free(conn);
 494
 495                 dmsg_msg_reply(msg, 0);
 496                 /* state invalid after reply */
 497                 break;
 498         default:
 499                 iocom->usrmsg_callback(msg, 1);
 500 #if 0
 501                 if (msg->any.head.cmd & DMSGF_DELETE)
 502                         goto deleteconn;
 503                 dmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
 504 #endif
 505                 break;
 506         }
 507         pthread_mutex_unlock(&cluster_mtx);
 508 }
 509
 510 /*
 511  * LNK_SPAN - Spanning tree protocol message reception
 512  *            (incoming iocom lock not held)
 513  *
 514  * Receive a spanning tree transactional message, creating or destroying
 515  * a SPAN and propagating it to other iocoms.
 516  */
 517 void
 518 dmsg_lnk_span(dmsg_msg_t *msg)
 519 {
 520         dmsg_state_t *state = msg->state;
 521         dmsg_iocom_t *iocom = state->iocom;
 522         h2span_cluster_t dummy_cls;
 523         h2span_node_t dummy_node;
 524         h2span_cluster_t *cls;
 525         h2span_node_t *node;
 526         h2span_link_t *slink;
 527         h2span_relay_t *relay;
 528         char *alloc = NULL;
 529
 530         /*
 531          * Ignore reply to LNK_SPAN.  The reply is expected and will commands
 532          * to flow in both directions on the open transaction.  This will also
 533          * ignore DMSGF_REPLY|DMSGF_DELETE messages.  Since we take no action
 534          * if the other end unexpectedly closes their side of the transaction,
 535          * we can ignore that too.
 536          */
 537         if (msg->any.head.cmd & DMSGF_REPLY) {
 538                 printf("Ignore reply to LNK_SPAN\n");
 539                 return;
 540         }
 541
 542         pthread_mutex_lock(&cluster_mtx);
 543
 544         /*
 545          * On transaction start we initialize the tracking infrastructure
 546          */
 547         if (msg->any.head.cmd & DMSGF_CREATE) {
 548                 assert(state->func == NULL);
 549                 state->func = dmsg_lnk_span;
 550
 551                 dmsg_termstr(msg->any.lnk_span.cl_label);
 552                 dmsg_termstr(msg->any.lnk_span.fs_label);
 553
 554                 /*
 555                  * Find the cluster
 556                  */
 557                 dummy_cls.pfs_clid = msg->any.lnk_span.pfs_clid;
 558                 dummy_cls.peer_type = msg->any.lnk_span.peer_type;
 559                 bcopy(msg->any.lnk_span.cl_label,
 560                       dummy_cls.cl_label,
 561                       sizeof(dummy_cls.cl_label));
 562                 cls = RB_FIND(h2span_cluster_tree, &cluster_tree, &dummy_cls);
 563                 if (cls == NULL) {
 564                         cls = dmsg_alloc(sizeof(*cls));
 565                         cls->pfs_clid = msg->any.lnk_span.pfs_clid;
 566                         cls->peer_type = msg->any.lnk_span.peer_type;
 567                         bcopy(msg->any.lnk_span.cl_label,
 568                               cls->cl_label,
 569                               sizeof(cls->cl_label));
 570                         RB_INIT(&cls->tree);
 571                         RB_INSERT(h2span_cluster_tree, &cluster_tree, cls);
 572                 }
 573
 574                 /*
 575                  * Find the node
 576                  */
 577                 dummy_node.pfs_fsid = msg->any.lnk_span.pfs_fsid;
 578                 bcopy(msg->any.lnk_span.fs_label, dummy_node.fs_label,
 579                       sizeof(dummy_node.fs_label));
 580                 node = RB_FIND(h2span_node_tree, &cls->tree, &dummy_node);
 581                 if (node == NULL) {
 582                         node = dmsg_alloc(sizeof(*node));
 583                         node->pfs_fsid = msg->any.lnk_span.pfs_fsid;
 584                         node->pfs_type = msg->any.lnk_span.pfs_type;
 585                         bcopy(msg->any.lnk_span.fs_label,
 586                               node->fs_label,
 587                               sizeof(node->fs_label));
 588                         node->cls = cls;
 589                         RB_INIT(&node->tree);
 590                         RB_INSERT(h2span_node_tree, &cls->tree, node);
 591                 }
 592
 593                 /*
 594                  * Create the link
 595                  *
 596                  * NOTE: Sub-transactions on the incoming SPAN can be used
 597                  *       to talk to the originator.  We should not set-up
 598                  *       state->relay for incoming SPANs since our sub-trans
 599                  *       is running on the same interface (i.e. no actual
 600                  *       relaying need be done).
 601                  *
 602                  * NOTE: Later on when we relay the SPAN out the outgoing
 603                  *       SPAN state will be set up to relay back to this
 604                  *       state.
 605                  *
 606                  * NOTE: It is possible for SPAN targets to send one-way
 607                  *       messages to the originator but it is not possible
 608                  *       for the originator to (currently) broadcast one-way
 609                  *       messages to all of its SPAN targets.  The protocol
 610                  *       allows such a feature to be added in the future.
 611                  */
 612                 assert(state->any.link == NULL);
 613                 slink = dmsg_alloc(sizeof(*slink));
 614                 TAILQ_INIT(&slink->relayq);
 615                 slink->node = node;
 616                 slink->state = state;
 617                 state->any.link = slink;
 618                 slink->lnk_span = msg->any.lnk_span;
 619
 620                 RB_INSERT(h2span_link_tree, &node->tree, slink);
 621
 622                 fprintf(stderr,
 623                         "LNK_SPAN(thr %p): %p %s cl=%s fs=%s dist=%d\n",
 624                         iocom,
 625                         slink,
 626                         dmsg_uuid_to_str(&msg->any.lnk_span.pfs_clid, &alloc),
 627                         msg->any.lnk_span.cl_label,
 628                         msg->any.lnk_span.fs_label,
 629                         msg->any.lnk_span.dist);
 630                 free(alloc);
 631 #if 0
 632                 dmsg_relay_scan(NULL, node);
 633 #endif
 634                 /*
 635                  * Ack the open, which will issue a CREATE on our side, and
 636                  * leave the transaction open.  Necessary to allow the
 637                  * transaction to be used as a virtual circuit.
 638                  */
 639                 dmsg_state_result(state, 0);
 640                 dmsg_iocom_signal(iocom);
 641         }
 642
 643         /*
 644          * On transaction terminate we remove the tracking infrastructure.
 645          */
 646         if (msg->any.head.cmd & DMSGF_DELETE) {
 647                 slink = state->any.link;
 648                 assert(slink != NULL);
 649                 node = slink->node;
 650                 cls = node->cls;
 651
 652                 fprintf(stderr, "LNK_DELE(thr %p): %p %s cl=%s fs=%s\n",
 653                         iocom,
 654                         slink,
 655                         dmsg_uuid_to_str(&cls->pfs_clid, &alloc),
 656                         cls->cl_label,
 657                         node->fs_label);
 658                 free(alloc);
 659
 660                 /*
 661                  * Clean out all relays.  This requires terminating each
 662                  * relay transaction.
 663                  */
 664                 while ((relay = TAILQ_FIRST(&slink->relayq)) != NULL) {
 665                         dmsg_relay_delete(relay);
 666                 }
 667
 668                 /*
 669                  * Clean out the topology
 670                  */
 671                 RB_REMOVE(h2span_link_tree, &node->tree, slink);
 672                 if (RB_EMPTY(&node->tree)) {
 673                         RB_REMOVE(h2span_node_tree, &cls->tree, node);
 674                         if (RB_EMPTY(&cls->tree) && cls->refs == 0) {
 675                                 RB_REMOVE(h2span_cluster_tree,
 676                                           &cluster_tree, cls);
 677                                 dmsg_free(cls);
 678                         }
 679                         node->cls = NULL;
 680                         dmsg_free(node);
 681                         node = NULL;
 682                 }
 683                 state->any.link = NULL;
 684                 slink->state = NULL;
 685                 slink->node = NULL;
 686                 dmsg_free(slink);
 687
 688                 /*
 689                  * We have to terminate the transaction
 690                  */
 691                 dmsg_state_reply(state, 0);
 692                 /* state invalid after reply */
 693
 694                 /*
 695                  * If the node still exists issue any required updates.  If
 696                  * it doesn't then all related relays have already been
 697                  * removed and there's nothing left to do.
 698                  */
 699 #if 0
 700                 if (node)
 701                         dmsg_relay_scan(NULL, node);
 702 #endif
 703                 if (node)
 704                         dmsg_iocom_signal(iocom);
 705         }
 706
 707         pthread_mutex_unlock(&cluster_mtx);
 708 }
 709
 710 /*
 711  * Update relay transactions for SPANs.
 712  *
 713  * Called with cluster_mtx held.
 714  */
 715 static void dmsg_relay_scan_specific(h2span_node_t *node,
 716                                         h2span_conn_t *conn);
 717
 718 static void
 719 dmsg_relay_scan(h2span_conn_t *conn, h2span_node_t *node)
 720 {
 721         h2span_cluster_t *cls;
 722
 723         if (node) {
 724                 /*
 725                  * Iterate specific node
 726                  */
 727                 TAILQ_FOREACH(conn, &connq, entry)
 728                         dmsg_relay_scan_specific(node, conn);
 729         } else {
 730                 /*
 731                  * Full iteration.
 732                  *
 733                  * Iterate cluster ids, nodes, and either a specific connection
 734                  * or all connections.
 735                  */
 736                 RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
 737                         /*
 738                          * Iterate node ids
 739                          */
 740                         RB_FOREACH(node, h2span_node_tree, &cls->tree) {
 741                                 /*
 742                                  * Synchronize the node's link (received SPANs)
 743                                  * with each connection's relays.
 744                                  */
 745                                 if (conn) {
 746                                         dmsg_relay_scan_specific(node, conn);
 747                                 } else {
 748                                         TAILQ_FOREACH(conn, &connq, entry) {
 749                                             dmsg_relay_scan_specific(node,
 750                                                                         conn);
 751                                         }
 752                                         assert(conn == NULL);
 753                                 }
 754                         }
 755                 }
 756         }
 757 }
 758
 759 /*
 760  * Update the relay'd SPANs for this (node, conn).
 761  *
 762  * Iterate links and adjust relays to match.  We only propagate the top link
 763  * for now (XXX we want to propagate the top two).
 764  *
 765  * The dmsg_relay_scan_cmp() function locates the first relay element
 766  * for any given node.  The relay elements will be sub-sorted by dist.
 767  */
 768 struct relay_scan_info {
 769         h2span_node_t *node;
 770         h2span_relay_t *relay;
 771 };
 772
 773 static int
 774 dmsg_relay_scan_cmp(h2span_relay_t *relay, void *arg)
 775 {
 776         struct relay_scan_info *info = arg;
 777
 778         if ((intptr_t)relay->source_rt->any.link->node < (intptr_t)info->node)
 779                 return(-1);
 780         if ((intptr_t)relay->source_rt->any.link->node > (intptr_t)info->node)
 781                 return(1);
 782         return(0);
 783 }
 784
 785 static int
 786 dmsg_relay_scan_callback(h2span_relay_t *relay, void *arg)
 787 {
 788         struct relay_scan_info *info = arg;
 789
 790         info->relay = relay;
 791         return(-1);
 792 }
 793
 794 static void
 795 dmsg_relay_scan_specific(h2span_node_t *node, h2span_conn_t *conn)
 796 {
 797         struct relay_scan_info info;
 798         h2span_relay_t *relay;
 799         h2span_relay_t *next_relay;
 800         h2span_link_t *slink;
 801         dmsg_lnk_conn_t *lconn;
 802         dmsg_lnk_span_t *lspan;
 803         int count;
 804         int maxcount = 2;
 805 #ifdef REQUIRE_SYMMETRICAL
 806         uint32_t lastdist = DMSG_SPAN_MAXDIST;
 807         uint32_t lastrnss = 0;
 808 #endif
 809
 810         info.node = node;
 811         info.relay = NULL;
 812
 813         /*
 814          * Locate the first related relay for the node on this connection.
 815          * relay will be NULL if there were none.
 816          */
 817         RB_SCAN(h2span_relay_tree, &conn->tree,
 818                 dmsg_relay_scan_cmp, dmsg_relay_scan_callback, &info);
 819         relay = info.relay;
 820         info.relay = NULL;
 821         if (relay)
 822                 assert(relay->source_rt->any.link->node == node);
 823
 824         if (DMsgDebugOpt > 8)
 825                 fprintf(stderr, "relay scan for connection %p\n", conn);
 826
 827         /*
 828          * Iterate the node's links (received SPANs) in distance order,
 829          * lowest (best) dist first.
 830          *
 831          * PROPAGATE THE BEST LINKS OVER THE SPECIFIED CONNECTION.
 832          *
 833          * Track relays while iterating the best links and construct
 834          * missing relays when necessary.
 835          *
 836          * (If some prior better link was removed it would have also
 837          *  removed the relay, so the relay can only match exactly or
 838          *  be worse).
 839          */
 840         count = 0;
 841         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
 842                 /*
 843                  * Increment count of successful relays.  This isn't
 844                  * quite accurate if we break out but nothing after
 845                  * the loop uses (count).
 846                  *
 847                  * If count exceeds the maximum number of relays we desire
 848                  * we normally want to break out.  However, in order to
 849                  * guarantee a symmetric path we have to continue if both
 850                  * (dist) and (rnss) continue to match.  Otherwise the SPAN
 851                  * propagation in the reverse direction may choose different
 852                  * routes and we will not have a symmetric path.
 853                  *
 854                  * NOTE: Spanning tree does not have to be symmetrical so
 855                  *       this code is not currently enabled.
 856                  */
 857                 if (++count >= maxcount) {
 858 #ifdef REQUIRE_SYMMETRICAL
 859                         if (lastdist != slink->lnk_span.dist ||
 860                             lastrnss != slink->lnk_span.rnss) {
 861                                 break;
 862                         }
 863 #else
 864                         break;
 865 #endif
 866                         /* go beyond the nominal maximum desired relays */
 867                 }
 868
 869                 /*
 870                  * Match, relay already in-place, get the next
 871                  * relay to match against the next slink.
 872                  */
 873                 if (relay && relay->source_rt->any.link == slink) {
 874                         relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 875                         continue;
 876                 }
 877
 878                 /*
 879                  * We might want this SLINK, if it passes our filters.
 880                  *
 881                  * The spanning tree can cause closed loops so we have
 882                  * to limit slink->dist.
 883                  */
 884                 if (slink->lnk_span.dist > DMSG_SPAN_MAXDIST)
 885                         break;
 886
 887                 /*
 888                  * Don't bother transmitting a LNK_SPAN out the same
 889                  * connection it came in on.  Trivial optimization.
 890                  */
 891                 if (slink->state->iocom == conn->state->iocom)
 892                         break;
 893
 894                 /*
 895                  * NOTE ON FILTERS: The protocol spec allows non-requested
 896                  * SPANs to be transmitted, the other end is expected to
 897                  * leave their transactions open but otherwise ignore them.
 898                  *
 899                  * Don't bother transmitting if the remote connection
 900                  * is not accepting this SPAN's peer_type.
 901                  *
 902                  * pfs_mask is typically used so pure clients can filter
 903                  * out receiving SPANs for other pure clients.
 904                  */
 905                 lspan = &slink->lnk_span;
 906                 lconn = &conn->lnk_conn;
 907                 if (((1LLU << lspan->peer_type) & lconn->peer_mask) == 0)
 908                         break;
 909                 if (((1LLU << lspan->pfs_type) & lconn->pfs_mask) == 0)
 910                         break;
 911
 912                 /*
 913                  * Do not give pure clients visibility to other pure clients
 914                  */
 915                 if (lconn->pfs_type == DMSG_PFSTYPE_CLIENT &&
 916                     lspan->pfs_type == DMSG_PFSTYPE_CLIENT) {
 917                         break;
 918                 }
 919
 920                 /*
 921                  * Connection filter, if cluster uuid is not NULL it must
 922                  * match the span cluster uuid.  Only applies when the
 923                  * peer_type matches.
 924                  */
 925                 if (lspan->peer_type == lconn->peer_type &&
 926                     !uuid_is_nil(&lconn->pfs_clid, NULL) &&
 927                     uuid_compare(&slink->node->cls->pfs_clid,
 928                                  &lconn->pfs_clid, NULL)) {
 929                         break;
 930                 }
 931
 932                 /*
 933                  * Connection filter, if cluster label is not empty it must
 934                  * match the span cluster label.  Only applies when the
 935                  * peer_type matches.
 936                  */
 937                 if (lspan->peer_type == lconn->peer_type &&
 938                     lconn->cl_label[0] &&
 939                     strcmp(lconn->cl_label, slink->node->cls->cl_label)) {
 940                         break;
 941                 }
 942
 943                 /*
 944                  * NOTE! pfs_fsid differentiates nodes within the same cluster
 945                  *       so we obviously don't want to match those.  Similarly
 946                  *       for fs_label.
 947                  */
 948
 949                 /*
 950                  * Ok, we've accepted this SPAN for relaying.
 951                  */
 952                 assert(relay == NULL ||
 953                        relay->source_rt->any.link->node != slink->node ||
 954                        relay->source_rt->any.link->lnk_span.dist >=
 955                         slink->lnk_span.dist);
 956                 relay = dmsg_generate_relay(conn, slink);
 957 #ifdef REQUIRE_SYMMETRICAL
 958                 lastdist = slink->lnk_span.dist;
 959                 lastrnss = slink->lnk_span.rnss;
 960 #endif
 961
 962                 /*
 963                  * Match (created new relay), get the next relay to
 964                  * match against the next slink.
 965                  */
 966                 relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 967         }
 968
 969         /*
 970          * Any remaining relay's belonging to this connection which match
 971          * the node are in excess of the current aggregate spanning state
 972          * and should be removed.
 973          */
 974         while (relay && relay->source_rt->any.link->node == node) {
 975                 next_relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 976                 fprintf(stderr, "RELAY DELETE FROM EXTRAS\n");
 977                 dmsg_relay_delete(relay);
 978                 relay = next_relay;
 979         }
 980 }
 981
 982 /*
 983  * Find the slink associated with the msgid and return its state,
 984  * so the caller can issue a transaction.
 985  */
 986 dmsg_state_t *
 987 dmsg_findspan(const char *label)
 988 {
 989         dmsg_state_t *state;
 990         h2span_cluster_t *cls;
 991         h2span_node_t *node;
 992         h2span_link_t *slink;
 993         uint64_t msgid = strtoull(label, NULL, 16);
 994
 995         pthread_mutex_lock(&cluster_mtx);
 996
 997         state = NULL;
 998         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
 999                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1000                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1001                                 if (slink->state->msgid == msgid) {
1002                                         state = slink->state;
1003                                         goto done;
1004                                 }
1005                         }
1006                 }
1007         }
1008 done:
1009         pthread_mutex_unlock(&cluster_mtx);
1010
1011         fprintf(stderr, "findspan: %p\n", state);
1012
1013         return state;
1014 }
1015
1016
1017 /*
1018  * Helper function to generate missing relay on target connection.
1019  *
1020  * cluster_mtx must be held
1021  */
1022 static
1023 h2span_relay_t *
1024 dmsg_generate_relay(h2span_conn_t *conn, h2span_link_t *slink)
1025 {
1026         h2span_relay_t *relay;
1027         dmsg_msg_t *msg;
1028
1029         relay = dmsg_alloc(sizeof(*relay));
1030         relay->conn = conn;
1031         relay->source_rt = slink->state;
1032         /* relay->source_rt->any.link = slink; */
1033
1034         /*
1035          * NOTE: relay->target_rt->any.relay set to relay by alloc.
1036          *
1037          * NOTE: LNK_SPAN is transmitted as a top-level transaction.
1038          */
1039         msg = dmsg_msg_alloc(&conn->state->iocom->state0,
1040                              0, DMSG_LNK_SPAN | DMSGF_CREATE,
1041                              dmsg_lnk_relay, relay);
1042         relay->target_rt = msg->state;
1043
1044         msg->any.lnk_span = slink->lnk_span;
1045         msg->any.lnk_span.dist = slink->lnk_span.dist + 1;
1046         msg->any.lnk_span.rnss = slink->lnk_span.rnss + dmsg_rnss();
1047
1048         RB_INSERT(h2span_relay_tree, &conn->tree, relay);
1049         TAILQ_INSERT_TAIL(&slink->relayq, relay, entry);
1050
1051         /*
1052          * Seed the relay so new sub-transactions received on the outgoing
1053          * SPAN circuit are relayed back to the originator.
1054          */
1055         msg->state->relay = relay->source_rt;
1056         dmsg_state_hold(msg->state->relay);
1057
1058         dmsg_msg_write(msg);
1059
1060         return (relay);
1061 }
1062
1063 /*
1064  * Messages received on relay SPANs.  These are open transactions so it is
1065  * in fact possible for the other end to close the transaction.
1066  *
1067  * XXX MPRACE on state structure
1068  */
1069 static void
1070 dmsg_lnk_relay(dmsg_msg_t *msg)
1071 {
1072         dmsg_state_t *state = msg->state;
1073         h2span_relay_t *relay;
1074
1075         assert(msg->any.head.cmd & DMSGF_REPLY);
1076
1077         if (msg->any.head.cmd & DMSGF_DELETE) {
1078                 pthread_mutex_lock(&cluster_mtx);
1079                 fprintf(stderr, "RELAY DELETE FROM LNK_RELAY MSG\n");
1080                 if ((relay = state->any.relay) != NULL) {
1081                         dmsg_relay_delete(relay);
1082                 } else {
1083                         dmsg_state_reply(state, 0);
1084                 }
1085                 pthread_mutex_unlock(&cluster_mtx);
1086         }
1087 }
1088
1089 /*
1090  * cluster_mtx held by caller
1091  */
1092 static
1093 void
1094 dmsg_relay_delete(h2span_relay_t *relay)
1095 {
1096         fprintf(stderr,
1097                 "RELAY DELETE %p RELAY %p ON CLS=%p NODE=%p "
1098                 "DIST=%d FD %d STATE %p\n",
1099                 relay->source_rt->any.link,
1100                 relay,
1101                 relay->source_rt->any.link->node->cls,
1102                 relay->source_rt->any.link->node,
1103                 relay->source_rt->any.link->lnk_span.dist,
1104                 relay->conn->state->iocom->sock_fd,
1105                 relay->target_rt);
1106
1107         RB_REMOVE(h2span_relay_tree, &relay->conn->tree, relay);
1108         TAILQ_REMOVE(&relay->source_rt->any.link->relayq, relay, entry);
1109
1110         if (relay->target_rt) {
1111                 relay->target_rt->any.relay = NULL;
1112                 dmsg_state_reply(relay->target_rt, 0);
1113                 /* state invalid after reply */
1114                 relay->target_rt = NULL;
1115         }
1116
1117         /*
1118          * NOTE: relay->source_rt->refs is held by the relay SPAN
1119          *       state, not by this relay structure.
1120          */
1121         relay->conn = NULL;
1122         relay->source_rt = NULL;
1123         dmsg_free(relay);
1124 }
1125
1126 /************************************************************************
1127  *                      ROUTER AND MESSAGING HANDLES                    *
1128  ************************************************************************
1129  *
1130  * Basically the idea here is to provide a stable data structure which
1131  * can be localized to the caller for higher level protocols to work with.
1132  * Depends on the context, these dmsg_handle's can be pooled by use-case
1133  * and remain persistent through a client (or mount point's) life.
1134  */
1135
1136 #if 0
1137 /*
1138  * Obtain a stable handle on a cluster given its uuid.  This ties directly
1139  * into the global cluster topology, creating the structure if necessary
1140  * (even if the uuid does not exist or does not exist yet), and preventing
1141  * the structure from getting ripped out from under us while we hold a
1142  * pointer to it.
1143  */
1144 h2span_cluster_t *
1145 dmsg_cluster_get(uuid_t *pfs_clid)
1146 {
1147         h2span_cluster_t dummy_cls;
1148         h2span_cluster_t *cls;
1149
1150         dummy_cls.pfs_clid = *pfs_clid;
1151         pthread_mutex_lock(&cluster_mtx);
1152         cls = RB_FIND(h2span_cluster_tree, &cluster_tree, &dummy_cls);
1153         if (cls)
1154                 ++cls->refs;
1155         pthread_mutex_unlock(&cluster_mtx);
1156         return (cls);
1157 }
1158
1159 void
1160 dmsg_cluster_put(h2span_cluster_t *cls)
1161 {
1162         pthread_mutex_lock(&cluster_mtx);
1163         assert(cls->refs > 0);
1164         --cls->refs;
1165         if (RB_EMPTY(&cls->tree) && cls->refs == 0) {
1166                 RB_REMOVE(h2span_cluster_tree,
1167                           &cluster_tree, cls);
1168                 dmsg_free(cls);
1169         }
1170         pthread_mutex_unlock(&cluster_mtx);
1171 }
1172
1173 /*
1174  * Obtain a stable handle to a specific cluster node given its uuid.
1175  * This handle does NOT lock in the route to the node and is typically
1176  * used as part of the dmsg_handle_*() API to obtain a set of
1177  * stable nodes.
1178  */
1179 h2span_node_t *
1180 dmsg_node_get(h2span_cluster_t *cls, uuid_t *pfs_fsid)
1181 {
1182 }
1183
1184 #endif
1185
1186 /*
1187  * Dumps the spanning tree
1188  *
1189  * DEBUG ONLY
1190  */
1191 void
1192 dmsg_shell_tree(dmsg_iocom_t *iocom, char *cmdbuf __unused)
1193 {
1194         h2span_cluster_t *cls;
1195         h2span_node_t *node;
1196         h2span_link_t *slink;
1197         h2span_relay_t *relay;
1198         char *uustr = NULL;
1199
1200         pthread_mutex_lock(&cluster_mtx);
1201         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
1202                 dmsg_printf(iocom, "Cluster %s %s (%s)\n",
1203                                   dmsg_peer_type_to_str(cls->peer_type),
1204                                   dmsg_uuid_to_str(&cls->pfs_clid, &uustr),
1205                                   cls->cl_label);
1206                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1207                         dmsg_printf(iocom, "    Node %02x %s (%s)\n",
1208                                 node->pfs_type,
1209                                 dmsg_uuid_to_str(&node->pfs_fsid, &uustr),
1210                                 node->fs_label);
1211                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1212                                 dmsg_printf(iocom,
1213                                             "\tSLink msgid %016jx "
1214                                             "dist=%d via %d\n",
1215                                             (intmax_t)slink->state->msgid,
1216                                             slink->lnk_span.dist,
1217                                             slink->state->iocom->sock_fd);
1218                                 TAILQ_FOREACH(relay, &slink->relayq, entry) {
1219                                         dmsg_printf(iocom,
1220                                             "\t    Relay-out msgid %016jx "
1221                                             "via %d\n",
1222                                             (intmax_t)relay->target_rt->msgid,
1223                                             relay->target_rt->iocom->sock_fd);
1224                                 }
1225                         }
1226                 }
1227         }
1228         pthread_mutex_unlock(&cluster_mtx);
1229         if (uustr)
1230                 free(uustr);
1231 #if 0
1232         TAILQ_FOREACH(conn, &connq, entry) {
1233         }
1234 #endif
1235 }
1236
1237 /*
1238  * DEBUG ONLY
1239  *
1240  * Locate the state representing an incoming LNK_SPAN given its msgid.
1241  */
1242 int
1243 dmsg_debug_findspan(uint64_t msgid, dmsg_state_t **statep)
1244 {
1245         h2span_cluster_t *cls;
1246         h2span_node_t *node;
1247         h2span_link_t *slink;
1248
1249         pthread_mutex_lock(&cluster_mtx);
1250         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
1251                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1252                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1253                                 if (slink->state->msgid == msgid) {
1254                                         *statep = slink->state;
1255                                         goto found;
1256                                 }
1257                         }
1258                 }
1259         }
1260         pthread_mutex_unlock(&cluster_mtx);
1261         *statep = NULL;
1262         return(ENOENT);
1263 found:
1264         pthread_mutex_unlock(&cluster_mtx);
1265         return(0);
1266 }
1267
1268 /*
1269  * Random number sub-sort value to add to SPAN rnss fields on relay.
1270  * This allows us to differentiate spans with the same <dist> field
1271  * for relaying purposes.  We must normally limit the number of relays
1272  * for any given SPAN origination but we must also guarantee that a
1273  * symmetric reverse path exists, so we use the rnss field as a sub-sort
1274  * (since there can be thousands or millions if we only match on <dist>),
1275  * and if there STILL too many spans we go past the limit.
1276  */
1277 static
1278 uint32_t
1279 dmsg_rnss(void)
1280 {
1281         if (DMsgRNSS == 0) {
1282                 pthread_mutex_lock(&cluster_mtx);
1283                 while (DMsgRNSS == 0) {
1284                         srandomdev();
1285                         DMsgRNSS = random();
1286                 }
1287                 pthread_mutex_unlock(&cluster_mtx);
1288         }
1289         return(DMsgRNSS);
1290 }