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 {peer_id, pfs_id}.
  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 peer id (peer_id),
 126  * node (pfs_id), 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  peer_id;                /* shared fsid */
 132         uint8_t peer_type;
 133         uint8_t reserved01[7];
 134         char    peer_label[128];        /* string identification */
 135         int     refs;                   /* prevents destruction */
 136 };
 137
 138 struct h2span_node {
 139         RB_ENTRY(h2span_node) rbnode;
 140         struct h2span_link_tree tree;
 141         struct h2span_cluster *cls;
 142         uint8_t pfs_type;
 143         uint8_t reserved01[7];
 144         uuid_t  pfs_id;                 /* unique pfs id */
 145         char    pfs_label[128];         /* string identification */
 146         void    *opaque;
 147 };
 148
 149 struct h2span_link {
 150         RB_ENTRY(h2span_link) rbnode;
 151         dmsg_state_t    *state;         /* state<->link */
 152         struct h2span_node *node;       /* related node */
 153         struct h2span_relay_queue relayq; /* relay out */
 154         dmsg_lnk_span_t lnk_span;
 155 };
 156
 157 /*
 158  * Any LNK_SPAN transactions we receive which are relayed out other
 159  * connections utilize this structure to track the LNK_SPAN transactions
 160  * we initiate (relay out) on other connections.  We only relay out
 161  * LNK_SPANs on connections we have an open CONN transaction for.
 162  *
 163  * The relay structure points to the outgoing LNK_SPAN trans (out_state)
 164  * and to the incoming LNK_SPAN transaction (in_state).  The relay
 165  * structure holds refs on the related states.
 166  *
 167  * In many respects this is the core of the protocol... actually figuring
 168  * out what LNK_SPANs to relay.  The spanid used for relaying is the
 169  * address of the 'state' structure, which is why h2span_relay has to
 170  * be entered into a RB-TREE based at h2span_conn (so we can look
 171  * up the spanid to validate it).
 172  */
 173 struct h2span_relay {
 174         TAILQ_ENTRY(h2span_relay) entry;        /* from link */
 175         RB_ENTRY(h2span_relay) rbnode;          /* from h2span_conn */
 176         struct h2span_conn      *conn;          /* related CONN transaction */
 177         dmsg_state_t            *source_rt;     /* h2span_link state */
 178         dmsg_state_t            *target_rt;     /* h2span_relay state */
 179 };
 180
 181 typedef struct h2span_conn h2span_conn_t;
 182 typedef struct h2span_cluster h2span_cluster_t;
 183 typedef struct h2span_node h2span_node_t;
 184 typedef struct h2span_link h2span_link_t;
 185 typedef struct h2span_relay h2span_relay_t;
 186
 187 #define dmsg_termstr(array)     _dmsg_termstr((array), sizeof(array))
 188
 189 static h2span_relay_t *dmsg_generate_relay(h2span_conn_t *conn,
 190                                         h2span_link_t *slink);
 191 static uint32_t dmsg_rnss(void);
 192
 193 static __inline
 194 void
 195 _dmsg_termstr(char *base, size_t size)
 196 {
 197         base[size-1] = 0;
 198 }
 199
 200 /*
 201  * Cluster peer_type, uuid, AND label must match for a match
 202  */
 203 static
 204 int
 205 h2span_cluster_cmp(h2span_cluster_t *cls1, h2span_cluster_t *cls2)
 206 {
 207         int r;
 208
 209         if (cls1->peer_type < cls2->peer_type)
 210                 return(-1);
 211         if (cls1->peer_type > cls2->peer_type)
 212                 return(1);
 213         r = uuid_compare(&cls1->peer_id, &cls2->peer_id, NULL);
 214         if (r == 0)
 215                 r = strcmp(cls1->peer_label, cls2->peer_label);
 216
 217         return r;
 218 }
 219
 220 /*
 221  * Match against pfs_label/pfs_id.  Together these two items represent a
 222  * unique node.  In most cases the primary differentiator is pfs_id but
 223  * we also string-match fs_label.
 224  */
 225 static
 226 int
 227 h2span_node_cmp(h2span_node_t *node1, h2span_node_t *node2)
 228 {
 229         int r;
 230
 231         r = strcmp(node1->pfs_label, node2->pfs_label);
 232         if (r == 0)
 233                 r = uuid_compare(&node1->pfs_id, &node2->pfs_id, NULL);
 234         return (r);
 235 }
 236
 237 /*
 238  * Sort/subsort must match h2span_relay_cmp() under any given node
 239  * to make the aggregation algorithm easier, so the best links are
 240  * in the same sorted order as the best relays.
 241  *
 242  * NOTE: We cannot use link*->state->msgid because this msgid is created
 243  *       by each remote host and thus might wind up being the same.
 244  */
 245 static
 246 int
 247 h2span_link_cmp(h2span_link_t *link1, h2span_link_t *link2)
 248 {
 249         if (link1->lnk_span.dist < link2->lnk_span.dist)
 250                 return(-1);
 251         if (link1->lnk_span.dist > link2->lnk_span.dist)
 252                 return(1);
 253         if (link1->lnk_span.rnss < link2->lnk_span.rnss)
 254                 return(-1);
 255         if (link1->lnk_span.rnss > link2->lnk_span.rnss)
 256                 return(1);
 257 #if 1
 258         if ((uintptr_t)link1->state < (uintptr_t)link2->state)
 259                 return(-1);
 260         if ((uintptr_t)link1->state > (uintptr_t)link2->state)
 261                 return(1);
 262 #else
 263         if (link1->state->msgid < link2->state->msgid)
 264                 return(-1);
 265         if (link1->state->msgid > link2->state->msgid)
 266                 return(1);
 267 #endif
 268         return(0);
 269 }
 270
 271 /*
 272  * Relay entries are sorted by node, subsorted by distance and link
 273  * address (so we can match up the conn->tree relay topology with
 274  * a node's link topology).
 275  */
 276 static
 277 int
 278 h2span_relay_cmp(h2span_relay_t *relay1, h2span_relay_t *relay2)
 279 {
 280         h2span_link_t *link1 = relay1->source_rt->any.link;
 281         h2span_link_t *link2 = relay2->source_rt->any.link;
 282
 283         if ((intptr_t)link1->node < (intptr_t)link2->node)
 284                 return(-1);
 285         if ((intptr_t)link1->node > (intptr_t)link2->node)
 286                 return(1);
 287         if (link1->lnk_span.dist < link2->lnk_span.dist)
 288                 return(-1);
 289         if (link1->lnk_span.dist > link2->lnk_span.dist)
 290                 return(1);
 291         if (link1->lnk_span.rnss < link2->lnk_span.rnss)
 292                 return(-1);
 293         if (link1->lnk_span.rnss > link2->lnk_span.rnss)
 294                 return(1);
 295 #if 1
 296         if ((uintptr_t)link1->state < (uintptr_t)link2->state)
 297                 return(-1);
 298         if ((uintptr_t)link1->state > (uintptr_t)link2->state)
 299                 return(1);
 300 #else
 301         if (link1->state->msgid < link2->state->msgid)
 302                 return(-1);
 303         if (link1->state->msgid > link2->state->msgid)
 304                 return(1);
 305 #endif
 306         return(0);
 307 }
 308
 309 RB_PROTOTYPE_STATIC(h2span_cluster_tree, h2span_cluster,
 310              rbnode, h2span_cluster_cmp);
 311 RB_PROTOTYPE_STATIC(h2span_node_tree, h2span_node,
 312              rbnode, h2span_node_cmp);
 313 RB_PROTOTYPE_STATIC(h2span_link_tree, h2span_link,
 314              rbnode, h2span_link_cmp);
 315 RB_PROTOTYPE_STATIC(h2span_relay_tree, h2span_relay,
 316              rbnode, h2span_relay_cmp);
 317
 318 RB_GENERATE_STATIC(h2span_cluster_tree, h2span_cluster,
 319              rbnode, h2span_cluster_cmp);
 320 RB_GENERATE_STATIC(h2span_node_tree, h2span_node,
 321              rbnode, h2span_node_cmp);
 322 RB_GENERATE_STATIC(h2span_link_tree, h2span_link,
 323              rbnode, h2span_link_cmp);
 324 RB_GENERATE_STATIC(h2span_relay_tree, h2span_relay,
 325              rbnode, h2span_relay_cmp);
 326
 327 /*
 328  * Global mutex protects cluster_tree lookups, connq, mediaq.
 329  */
 330 static pthread_mutex_t cluster_mtx;
 331 static struct h2span_cluster_tree cluster_tree = RB_INITIALIZER(cluster_tree);
 332 static struct h2span_conn_queue connq = TAILQ_HEAD_INITIALIZER(connq);
 333 static struct dmsg_media_queue mediaq = TAILQ_HEAD_INITIALIZER(mediaq);
 334
 335 static void dmsg_lnk_span(dmsg_msg_t *msg);
 336 static void dmsg_lnk_conn(dmsg_msg_t *msg);
 337 static void dmsg_lnk_ping(dmsg_msg_t *msg);
 338 static void dmsg_lnk_relay(dmsg_msg_t *msg);
 339 static void dmsg_relay_scan(h2span_conn_t *conn, h2span_node_t *node);
 340 static void dmsg_relay_delete(h2span_relay_t *relay);
 341
 342 void
 343 dmsg_msg_lnk_signal(dmsg_iocom_t *iocom __unused)
 344 {
 345         pthread_mutex_lock(&cluster_mtx);
 346         dmsg_relay_scan(NULL, NULL);
 347         pthread_mutex_unlock(&cluster_mtx);
 348 }
 349
 350 /*
 351  * DMSG_PROTO_LNK - Generic DMSG_PROTO_LNK.
 352  *            (incoming iocom lock not held)
 353  *
 354  * This function is typically called for one-way and opening-transactions
 355  * since state->func is assigned after that, but it will also be called
 356  * if no state->func is assigned on transaction-open.
 357  */
 358 void
 359 dmsg_msg_lnk(dmsg_msg_t *msg)
 360 {
 361         dmsg_iocom_t *iocom = msg->state->iocom;
 362
 363         switch(msg->tcmd & DMSGF_BASECMDMASK) {
 364         case DMSG_LNK_CONN:
 365                 dmsg_lnk_conn(msg);
 366                 break;
 367         case DMSG_LNK_SPAN:
 368                 dmsg_lnk_span(msg);
 369                 break;
 370         case DMSG_LNK_PING:
 371                 dmsg_lnk_ping(msg);
 372                 break;
 373         default:
 374                 iocom->usrmsg_callback(msg, 1);
 375                 /* state invalid after reply */
 376                 break;
 377         }
 378 }
 379
 380 /*
 381  * LNK_CONN - iocom identify message reception.
 382  *            (incoming iocom lock not held)
 383  *
 384  * Remote node identifies itself to us, sets up a SPAN filter, and gives us
 385  * the ok to start transmitting SPANs.
 386  */
 387 void
 388 dmsg_lnk_conn(dmsg_msg_t *msg)
 389 {
 390         dmsg_state_t *state = msg->state;
 391         dmsg_iocom_t *iocom = state->iocom;
 392         dmsg_media_t *media;
 393         h2span_conn_t *conn;
 394         h2span_relay_t *relay;
 395         char *alloc = NULL;
 396
 397         pthread_mutex_lock(&cluster_mtx);
 398
 399         dmio_printf(iocom, 3,
 400                 "dmsg_lnk_conn: msg %p cmd %08x state %p "
 401                 "txcmd %08x rxcmd %08x\n",
 402                 msg, msg->any.head.cmd, state,
 403                 state->txcmd, state->rxcmd);
 404
 405         switch(msg->any.head.cmd & DMSGF_TRANSMASK) {
 406         case DMSG_LNK_CONN | DMSGF_CREATE:
 407         case DMSG_LNK_CONN | DMSGF_CREATE | DMSGF_DELETE:
 408                 /*
 409                  * On transaction start we allocate a new h2span_conn and
 410                  * acknowledge the request, leaving the transaction open.
 411                  * We then relay priority-selected SPANs.
 412                  */
 413                 dmio_printf(iocom, 3, "LNK_CONN(%08x): %s/%s\n",
 414                         (uint32_t)msg->any.head.msgid,
 415                         dmsg_uuid_to_str(&msg->any.lnk_conn.peer_id, &alloc),
 416                         msg->any.lnk_conn.peer_label);
 417                 free(alloc);
 418
 419                 conn = dmsg_alloc(sizeof(*conn));
 420                 assert(state->iocom->conn == NULL);
 421
 422                 RB_INIT(&conn->tree);
 423                 state->iocom->conn = conn;      /* XXX only one */
 424                 state->iocom->conn_msgid = state->msgid;
 425                 dmsg_state_hold(state);
 426                 conn->state = state;
 427                 state->func = dmsg_lnk_conn;
 428                 state->any.conn = conn;
 429                 TAILQ_INSERT_TAIL(&connq, conn, entry);
 430                 conn->lnk_conn = msg->any.lnk_conn;
 431
 432                 /*
 433                  * Set up media
 434                  */
 435                 TAILQ_FOREACH(media, &mediaq, entry) {
 436                         if (uuid_compare(&msg->any.lnk_conn.media_id,
 437                                          &media->media_id, NULL) == 0) {
 438                                 break;
 439                         }
 440                 }
 441                 if (media == NULL) {
 442                         media = dmsg_alloc(sizeof(*media));
 443                         media->media_id = msg->any.lnk_conn.media_id;
 444                         TAILQ_INSERT_TAIL(&mediaq, media, entry);
 445                 }
 446                 state->media = media;
 447                 ++media->refs;
 448
 449                 if ((msg->any.head.cmd & DMSGF_DELETE) == 0) {
 450                         iocom->usrmsg_callback(msg, 0);
 451                         dmsg_msg_result(msg, 0);
 452                         dmsg_iocom_signal(iocom);
 453                         break;
 454                 }
 455                 /* FALL THROUGH */
 456         case DMSG_LNK_CONN | DMSGF_DELETE:
 457         case DMSG_LNK_ERROR | DMSGF_DELETE:
 458                 /*
 459                  * On transaction terminate we clean out our h2span_conn
 460                  * and acknowledge the request, closing the transaction.
 461                  */
 462                 dmio_printf(iocom, 3, "%s\n", "LNK_CONN: Terminated");
 463                 conn = state->any.conn;
 464                 assert(conn);
 465
 466                 /*
 467                  * Adjust media refs
 468                  *
 469                  * Callback will clean out media config / user-opaque state
 470                  */
 471                 media = state->media;
 472                 --media->refs;
 473                 if (media->refs == 0) {
 474                         dmio_printf(iocom, 3, "%s\n", "Media shutdown");
 475                         TAILQ_REMOVE(&mediaq, media, entry);
 476                         pthread_mutex_unlock(&cluster_mtx);
 477                         iocom->usrmsg_callback(msg, 0);
 478                         pthread_mutex_lock(&cluster_mtx);
 479                         dmsg_free(media);
 480                 }
 481                 state->media = NULL;
 482
 483                 /*
 484                  * Clean out all relays.  This requires terminating each
 485                  * relay transaction.
 486                  */
 487                 while ((relay = RB_ROOT(&conn->tree)) != NULL) {
 488                         dmsg_relay_delete(relay);
 489                 }
 490
 491                 /*
 492                  * Clean out conn
 493                  */
 494                 conn->state = NULL;
 495                 msg->state->any.conn = NULL;
 496                 msg->state->iocom->conn = NULL;
 497                 TAILQ_REMOVE(&connq, conn, entry);
 498                 dmsg_free(conn);
 499
 500                 dmsg_msg_reply(msg, 0);
 501                 dmsg_state_drop(state);
 502                 /* state invalid after reply */
 503                 break;
 504         default:
 505                 iocom->usrmsg_callback(msg, 1);
 506 #if 0
 507                 if (msg->any.head.cmd & DMSGF_DELETE)
 508                         goto deleteconn;
 509                 dmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
 510 #endif
 511                 break;
 512         }
 513         pthread_mutex_unlock(&cluster_mtx);
 514 }
 515
 516 /*
 517  * LNK_SPAN - Spanning tree protocol message reception
 518  *            (incoming iocom lock not held)
 519  *
 520  * Receive a spanning tree transactional message, creating or destroying
 521  * a SPAN and propagating it to other iocoms.
 522  */
 523 void
 524 dmsg_lnk_span(dmsg_msg_t *msg)
 525 {
 526         dmsg_state_t *state = msg->state;
 527         dmsg_iocom_t *iocom = state->iocom;
 528         h2span_cluster_t dummy_cls;
 529         h2span_node_t dummy_node;
 530         h2span_cluster_t *cls;
 531         h2span_node_t *node;
 532         h2span_link_t *slink;
 533         h2span_relay_t *relay;
 534         char *alloc = NULL;
 535
 536         /*
 537          * XXX
 538          *
 539          * Ignore reply to LNK_SPAN.  The reply is expected and will commands
 540          * to flow in both directions on the open transaction.  This will also
 541          * ignore DMSGF_REPLY|DMSGF_DELETE messages.  Since we take no action
 542          * if the other end unexpectedly closes their side of the transaction,
 543          * we can ignore that too.
 544          */
 545         if (msg->any.head.cmd & DMSGF_REPLY) {
 546                 dmio_printf(iocom, 2, "%s\n",
 547                             "Ignore reply to LNK_SPAN");
 548                 return;
 549         }
 550
 551         pthread_mutex_lock(&cluster_mtx);
 552
 553         /*
 554          * On transaction start we initialize the tracking infrastructure
 555          */
 556         if (msg->any.head.cmd & DMSGF_CREATE) {
 557                 assert(state->func == NULL);
 558                 state->func = dmsg_lnk_span;
 559
 560                 dmsg_termstr(msg->any.lnk_span.peer_label);
 561                 dmsg_termstr(msg->any.lnk_span.pfs_label);
 562
 563                 /*
 564                  * Find the cluster
 565                  */
 566                 dummy_cls.peer_id = msg->any.lnk_span.peer_id;
 567                 dummy_cls.peer_type = msg->any.lnk_span.peer_type;
 568                 bcopy(msg->any.lnk_span.peer_label, dummy_cls.peer_label,
 569                       sizeof(dummy_cls.peer_label));
 570                 cls = RB_FIND(h2span_cluster_tree, &cluster_tree, &dummy_cls);
 571                 if (cls == NULL) {
 572                         cls = dmsg_alloc(sizeof(*cls));
 573                         cls->peer_id = msg->any.lnk_span.peer_id;
 574                         cls->peer_type = msg->any.lnk_span.peer_type;
 575                         bcopy(msg->any.lnk_span.peer_label,
 576                               cls->peer_label, sizeof(cls->peer_label));
 577                         RB_INIT(&cls->tree);
 578                         RB_INSERT(h2span_cluster_tree, &cluster_tree, cls);
 579                 }
 580
 581                 /*
 582                  * Find the node
 583                  */
 584                 dummy_node.pfs_id = msg->any.lnk_span.pfs_id;
 585                 bcopy(msg->any.lnk_span.pfs_label, dummy_node.pfs_label,
 586                       sizeof(dummy_node.pfs_label));
 587                 node = RB_FIND(h2span_node_tree, &cls->tree, &dummy_node);
 588                 if (node == NULL) {
 589                         node = dmsg_alloc(sizeof(*node));
 590                         node->pfs_id = msg->any.lnk_span.pfs_id;
 591                         node->pfs_type = msg->any.lnk_span.pfs_type;
 592                         bcopy(msg->any.lnk_span.pfs_label, node->pfs_label,
 593                               sizeof(node->pfs_label));
 594                         node->cls = cls;
 595                         RB_INIT(&node->tree);
 596                         RB_INSERT(h2span_node_tree, &cls->tree, node);
 597                 }
 598
 599                 /*
 600                  * Create the link
 601                  *
 602                  * NOTE: Sub-transactions on the incoming SPAN can be used
 603                  *       to talk to the originator.  We should not set-up
 604                  *       state->relay for incoming SPANs since our sub-trans
 605                  *       is running on the same interface (i.e. no actual
 606                  *       relaying need be done).
 607                  *
 608                  * NOTE: Later on when we relay the SPAN out the outgoing
 609                  *       SPAN state will be set up to relay back to this
 610                  *       state.
 611                  *
 612                  * NOTE: It is possible for SPAN targets to send one-way
 613                  *       messages to the originator but it is not possible
 614                  *       for the originator to (currently) broadcast one-way
 615                  *       messages to all of its SPAN targets.  The protocol
 616                  *       allows such a feature to be added in the future.
 617                  */
 618                 assert(state->any.link == NULL);
 619                 dmsg_state_hold(state);
 620                 slink = dmsg_alloc(sizeof(*slink));
 621                 TAILQ_INIT(&slink->relayq);
 622                 slink->node = node;
 623                 slink->state = state;
 624                 state->any.link = slink;
 625                 slink->lnk_span = msg->any.lnk_span;
 626
 627                 RB_INSERT(h2span_link_tree, &node->tree, slink);
 628
 629                 dmio_printf(iocom, 3,
 630                             "LNK_SPAN(thr %p): %p %s cl=%s fs=%s dist=%d\n",
 631                             iocom, slink,
 632                             dmsg_uuid_to_str(&msg->any.lnk_span.peer_id,
 633                                              &alloc),
 634                             msg->any.lnk_span.peer_label,
 635                             msg->any.lnk_span.pfs_label,
 636                             msg->any.lnk_span.dist);
 637                 free(alloc);
 638 #if 0
 639                 dmsg_relay_scan(NULL, node);
 640 #endif
 641                 /*
 642                  * Ack the open, which will issue a CREATE on our side, and
 643                  * leave the transaction open.  Necessary to allow the
 644                  * transaction to be used as a virtual circuit.
 645                  */
 646                 dmsg_state_result(state, 0);
 647                 dmsg_iocom_signal(iocom);
 648         }
 649
 650         /*
 651          * On transaction terminate we remove the tracking infrastructure.
 652          */
 653         if (msg->any.head.cmd & DMSGF_DELETE) {
 654                 slink = state->any.link;
 655                 assert(slink->state == state);
 656                 assert(slink != NULL);
 657                 node = slink->node;
 658                 cls = node->cls;
 659
 660                 dmio_printf(iocom, 3,
 661                             "LNK_DELE(thr %p): %p %s cl=%s fs=%s\n",
 662                             iocom, slink,
 663                             dmsg_uuid_to_str(&cls->peer_id, &alloc),
 664                             cls->peer_label,
 665                             node->pfs_label);
 666                 free(alloc);
 667
 668                 /*
 669                  * Clean out all relays.  This requires terminating each
 670                  * relay transaction.
 671                  */
 672                 while ((relay = TAILQ_FIRST(&slink->relayq)) != NULL) {
 673                         dmsg_relay_delete(relay);
 674                 }
 675
 676                 /*
 677                  * Clean out the topology
 678                  */
 679                 RB_REMOVE(h2span_link_tree, &node->tree, slink);
 680                 if (RB_EMPTY(&node->tree)) {
 681                         RB_REMOVE(h2span_node_tree, &cls->tree, node);
 682                         if (RB_EMPTY(&cls->tree) && cls->refs == 0) {
 683                                 RB_REMOVE(h2span_cluster_tree,
 684                                           &cluster_tree, cls);
 685                                 dmsg_free(cls);
 686                         }
 687                         node->cls = NULL;
 688                         dmsg_free(node);
 689                         node = NULL;
 690                 }
 691                 state->any.link = NULL;
 692                 slink->state = NULL;
 693                 slink->node = NULL;
 694                 dmsg_state_drop(state);
 695                 dmsg_free(slink);
 696
 697                 /*
 698                  * We have to terminate the transaction
 699                  */
 700                 dmsg_state_reply(state, 0);
 701                 /* state invalid after reply */
 702
 703                 /*
 704                  * If the node still exists issue any required updates.  If
 705                  * it doesn't then all related relays have already been
 706                  * removed and there's nothing left to do.
 707                  */
 708 #if 0
 709                 if (node)
 710                         dmsg_relay_scan(NULL, node);
 711 #endif
 712                 if (node)
 713                         dmsg_iocom_signal(iocom);
 714         }
 715
 716         pthread_mutex_unlock(&cluster_mtx);
 717 }
 718
 719 /*
 720  * Respond to a PING with a PING|REPLY, forward replies to the usermsg
 721  * callback.
 722  */
 723 static
 724 void
 725 dmsg_lnk_ping(dmsg_msg_t *msg)
 726 {
 727         dmsg_msg_t *rep;
 728
 729         if (msg->any.head.cmd & DMSGF_REPLY) {
 730                 msg->state->iocom->usrmsg_callback(msg, 1);
 731         } else {
 732                 rep = dmsg_msg_alloc(msg->state, 0,
 733                                      DMSG_LNK_PING | DMSGF_REPLY,
 734                                      NULL, NULL);
 735                 dmsg_msg_write(rep);
 736         }
 737 }
 738
 739 /*
 740  * Update relay transactions for SPANs.
 741  *
 742  * Called with cluster_mtx held.
 743  */
 744 static void dmsg_relay_scan_specific(h2span_node_t *node,
 745                                         h2span_conn_t *conn);
 746
 747 static void
 748 dmsg_relay_scan(h2span_conn_t *conn, h2span_node_t *node)
 749 {
 750         h2span_cluster_t *cls;
 751
 752         if (node) {
 753                 /*
 754                  * Iterate specific node
 755                  */
 756                 TAILQ_FOREACH(conn, &connq, entry)
 757                         dmsg_relay_scan_specific(node, conn);
 758         } else {
 759                 /*
 760                  * Full iteration.
 761                  *
 762                  * Iterate cluster ids, nodes, and either a specific connection
 763                  * or all connections.
 764                  */
 765                 RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
 766                         /*
 767                          * Iterate node ids
 768                          */
 769                         RB_FOREACH(node, h2span_node_tree, &cls->tree) {
 770                                 /*
 771                                  * Synchronize the node's link (received SPANs)
 772                                  * with each connection's relays.
 773                                  */
 774                                 if (conn) {
 775                                         dmsg_relay_scan_specific(node, conn);
 776                                 } else {
 777                                         TAILQ_FOREACH(conn, &connq, entry) {
 778                                             dmsg_relay_scan_specific(node,
 779                                                                         conn);
 780                                         }
 781                                         assert(conn == NULL);
 782                                 }
 783                         }
 784                 }
 785         }
 786 }
 787
 788 /*
 789  * Update the relay'd SPANs for this (node, conn).
 790  *
 791  * Iterate links and adjust relays to match.  We only propagate the top link
 792  * for now (XXX we want to propagate the top two).
 793  *
 794  * The dmsg_relay_scan_cmp() function locates the first relay element
 795  * for any given node.  The relay elements will be sub-sorted by dist.
 796  */
 797 struct relay_scan_info {
 798         h2span_node_t *node;
 799         h2span_relay_t *relay;
 800 };
 801
 802 static int
 803 dmsg_relay_scan_cmp(h2span_relay_t *relay, void *arg)
 804 {
 805         struct relay_scan_info *info = arg;
 806
 807         if ((intptr_t)relay->source_rt->any.link->node < (intptr_t)info->node)
 808                 return(-1);
 809         if ((intptr_t)relay->source_rt->any.link->node > (intptr_t)info->node)
 810                 return(1);
 811         return(0);
 812 }
 813
 814 static int
 815 dmsg_relay_scan_callback(h2span_relay_t *relay, void *arg)
 816 {
 817         struct relay_scan_info *info = arg;
 818
 819         info->relay = relay;
 820         return(-1);
 821 }
 822
 823 static void
 824 dmsg_relay_scan_specific(h2span_node_t *node, h2span_conn_t *conn)
 825 {
 826         struct relay_scan_info info;
 827         h2span_relay_t *relay;
 828         h2span_relay_t *next_relay;
 829         h2span_link_t *slink;
 830         dmsg_lnk_conn_t *lconn;
 831         dmsg_lnk_span_t *lspan;
 832         int count;
 833         int maxcount = 2;
 834 #ifdef REQUIRE_SYMMETRICAL
 835         uint32_t lastdist = DMSG_SPAN_MAXDIST;
 836         uint32_t lastrnss = 0;
 837 #endif
 838
 839         info.node = node;
 840         info.relay = NULL;
 841
 842         /*
 843          * Locate the first related relay for the node on this connection.
 844          * relay will be NULL if there were none.
 845          */
 846         RB_SCAN(h2span_relay_tree, &conn->tree,
 847                 dmsg_relay_scan_cmp, dmsg_relay_scan_callback, &info);
 848         relay = info.relay;
 849         info.relay = NULL;
 850         if (relay)
 851                 assert(relay->source_rt->any.link->node == node);
 852
 853         dm_printf(9, "relay scan for connection %p\n", conn);
 854
 855         /*
 856          * Iterate the node's links (received SPANs) in distance order,
 857          * lowest (best) dist first.
 858          *
 859          * PROPAGATE THE BEST LINKS OVER THE SPECIFIED CONNECTION.
 860          *
 861          * Track relays while iterating the best links and construct
 862          * missing relays when necessary.
 863          *
 864          * (If some prior better link was removed it would have also
 865          *  removed the relay, so the relay can only match exactly or
 866          *  be worse).
 867          */
 868         count = 0;
 869         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
 870                 /*
 871                  * Increment count of successful relays.  This isn't
 872                  * quite accurate if we break out but nothing after
 873                  * the loop uses (count).
 874                  *
 875                  * If count exceeds the maximum number of relays we desire
 876                  * we normally want to break out.  However, in order to
 877                  * guarantee a symmetric path we have to continue if both
 878                  * (dist) and (rnss) continue to match.  Otherwise the SPAN
 879                  * propagation in the reverse direction may choose different
 880                  * routes and we will not have a symmetric path.
 881                  *
 882                  * NOTE: Spanning tree does not have to be symmetrical so
 883                  *       this code is not currently enabled.
 884                  */
 885                 if (++count >= maxcount) {
 886 #ifdef REQUIRE_SYMMETRICAL
 887                         if (lastdist != slink->lnk_span.dist ||
 888                             lastrnss != slink->lnk_span.rnss) {
 889                                 break;
 890                         }
 891 #else
 892                         break;
 893 #endif
 894                         /* go beyond the nominal maximum desired relays */
 895                 }
 896
 897                 /*
 898                  * Match, relay already in-place, get the next
 899                  * relay to match against the next slink.
 900                  */
 901                 if (relay && relay->source_rt->any.link == slink) {
 902                         relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 903                         continue;
 904                 }
 905
 906                 /*
 907                  * We might want this SLINK, if it passes our filters.
 908                  *
 909                  * The spanning tree can cause closed loops so we have
 910                  * to limit slink->dist.
 911                  */
 912                 if (slink->lnk_span.dist > DMSG_SPAN_MAXDIST)
 913                         break;
 914
 915                 /*
 916                  * Don't bother transmitting a LNK_SPAN out the same
 917                  * connection it came in on.  Trivial optimization.
 918                  */
 919                 if (slink->state->iocom == conn->state->iocom)
 920                         break;
 921
 922                 /*
 923                  * NOTE ON FILTERS: The protocol spec allows non-requested
 924                  * SPANs to be transmitted, the other end is expected to
 925                  * leave their transactions open but otherwise ignore them.
 926                  *
 927                  * Don't bother transmitting if the remote connection
 928                  * is not accepting this SPAN's peer_type.
 929                  */
 930                 lspan = &slink->lnk_span;
 931                 lconn = &conn->lnk_conn;
 932                 if (((1LLU << lspan->peer_type) & lconn->peer_mask) == 0)
 933                         break;
 934
 935                 /*
 936                  * Do not give pure clients visibility to other pure clients
 937                  */
 938                 if (lconn->peer_type == DMSG_PEER_CLIENT &&
 939                     lspan->peer_type == DMSG_PEER_CLIENT) {
 940                         break;
 941                 }
 942
 943                 /*
 944                  * Clients can set peer_id to filter the peer_id of incoming
 945                  * spans.  Other peer types set peer_id to advertising their
 946                  * peer_id. XXX
 947                  *
 948                  * NOTE: peer_label is not a filter on clients, it identifies
 949                  *       the client just as it identifies other peer types.
 950                  */
 951                 if (lconn->peer_type == DMSG_PEER_CLIENT &&
 952                     !uuid_is_nil(&lconn->peer_id, NULL) &&
 953                     uuid_compare(&slink->node->cls->peer_id,
 954                                  &lconn->peer_id, NULL)) {
 955                         break;
 956                 }
 957
 958                 /*
 959                  * NOTE! pfs_id differentiates nodes within the same cluster
 960                  *       so we obviously don't want to match those.  Similarly
 961                  *       for pfs_label.
 962                  */
 963
 964                 /*
 965                  * Ok, we've accepted this SPAN for relaying.
 966                  */
 967                 assert(relay == NULL ||
 968                        relay->source_rt->any.link->node != slink->node ||
 969                        relay->source_rt->any.link->lnk_span.dist >=
 970                         slink->lnk_span.dist);
 971                 relay = dmsg_generate_relay(conn, slink);
 972 #ifdef REQUIRE_SYMMETRICAL
 973                 lastdist = slink->lnk_span.dist;
 974                 lastrnss = slink->lnk_span.rnss;
 975 #endif
 976
 977                 /*
 978                  * Match (created new relay), get the next relay to
 979                  * match against the next slink.
 980                  */
 981                 relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 982         }
 983
 984         /*
 985          * Any remaining relay's belonging to this connection which match
 986          * the node are in excess of the current aggregate spanning state
 987          * and should be removed.
 988          */
 989         while (relay && relay->source_rt->any.link->node == node) {
 990                 next_relay = RB_NEXT(h2span_relay_tree, &conn->tree, relay);
 991                 dm_printf(9, "%s\n", "RELAY DELETE FROM EXTRAS");
 992                 dmsg_relay_delete(relay);
 993                 relay = next_relay;
 994         }
 995 }
 996
 997 /*
 998  * Find the slink associated with the msgid and return its state,
 999  * so the caller can issue a transaction.
1000  */
1001 dmsg_state_t *
1002 dmsg_findspan(const char *label)
1003 {
1004         dmsg_state_t *state;
1005         h2span_cluster_t *cls;
1006         h2span_node_t *node;
1007         h2span_link_t *slink;
1008         uint64_t msgid = strtoull(label, NULL, 16);
1009
1010         pthread_mutex_lock(&cluster_mtx);
1011
1012         state = NULL;
1013         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
1014                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1015                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1016                                 if (slink->state->msgid == msgid) {
1017                                         state = slink->state;
1018                                         goto done;
1019                                 }
1020                         }
1021                 }
1022         }
1023 done:
1024         pthread_mutex_unlock(&cluster_mtx);
1025
1026         dm_printf(8, "findspan: %p\n", state);
1027
1028         return state;
1029 }
1030
1031
1032 /*
1033  * Helper function to generate missing relay on target connection.
1034  *
1035  * cluster_mtx must be held
1036  */
1037 static
1038 h2span_relay_t *
1039 dmsg_generate_relay(h2span_conn_t *conn, h2span_link_t *slink)
1040 {
1041         h2span_relay_t *relay;
1042         dmsg_msg_t *msg;
1043
1044         dmsg_state_hold(slink->state);
1045         relay = dmsg_alloc(sizeof(*relay));
1046         relay->conn = conn;
1047         relay->source_rt = slink->state;
1048         /* relay->source_rt->any.link = slink; */
1049
1050         /*
1051          * NOTE: relay->target_rt->any.relay set to relay by alloc.
1052          *
1053          * NOTE: LNK_SPAN is transmitted as a top-level transaction.
1054          */
1055         msg = dmsg_msg_alloc(&conn->state->iocom->state0,
1056                              0, DMSG_LNK_SPAN | DMSGF_CREATE,
1057                              dmsg_lnk_relay, relay);
1058         dmsg_state_hold(msg->state);
1059         relay->target_rt = msg->state;
1060
1061         msg->any.lnk_span = slink->lnk_span;
1062         msg->any.lnk_span.dist = slink->lnk_span.dist + 1;
1063         msg->any.lnk_span.rnss = slink->lnk_span.rnss + dmsg_rnss();
1064
1065         RB_INSERT(h2span_relay_tree, &conn->tree, relay);
1066         TAILQ_INSERT_TAIL(&slink->relayq, relay, entry);
1067
1068         /*
1069          * Seed the relay so new sub-transactions received on the outgoing
1070          * SPAN circuit are relayed back to the originator.
1071          */
1072         msg->state->relay = relay->source_rt;
1073         dmsg_state_hold(msg->state->relay);
1074
1075         dmsg_msg_write(msg);
1076
1077         return (relay);
1078 }
1079
1080 /*
1081  * Messages received on relay SPANs.  These are open transactions so it is
1082  * in fact possible for the other end to close the transaction.
1083  *
1084  * XXX MPRACE on state structure
1085  */
1086 static void
1087 dmsg_lnk_relay(dmsg_msg_t *msg)
1088 {
1089         dmsg_state_t *state = msg->state;
1090         h2span_relay_t *relay;
1091
1092         assert(msg->any.head.cmd & DMSGF_REPLY);
1093
1094         if (msg->any.head.cmd & DMSGF_DELETE) {
1095                 pthread_mutex_lock(&cluster_mtx);
1096                 dm_printf(8, "%s\n", "RELAY DELETE FROM LNK_RELAY MSG");
1097                 if ((relay = state->any.relay) != NULL) {
1098                         dmsg_relay_delete(relay);
1099                 } else {
1100                         dmsg_state_reply(state, 0);
1101                 }
1102                 pthread_mutex_unlock(&cluster_mtx);
1103         }
1104 }
1105
1106 /*
1107  * cluster_mtx held by caller
1108  */
1109 static
1110 void
1111 dmsg_relay_delete(h2span_relay_t *relay)
1112 {
1113         dm_printf(8,
1114                   "RELAY DELETE %p RELAY %p ON CLS=%p NODE=%p "
1115                   "DIST=%d FD %d STATE %p\n",
1116                   relay->source_rt->any.link,
1117                   relay,
1118                   relay->source_rt->any.link->node->cls,
1119                   relay->source_rt->any.link->node,
1120                   relay->source_rt->any.link->lnk_span.dist,
1121                   relay->conn->state->iocom->sock_fd,
1122                   relay->target_rt);
1123
1124         RB_REMOVE(h2span_relay_tree, &relay->conn->tree, relay);
1125         TAILQ_REMOVE(&relay->source_rt->any.link->relayq, relay, entry);
1126
1127         if (relay->target_rt) {
1128                 relay->target_rt->any.relay = NULL;
1129                 dmsg_state_reply(relay->target_rt, 0);
1130                 dmsg_state_drop(relay->target_rt);
1131                 /* state invalid after reply */
1132                 relay->target_rt = NULL;
1133         }
1134
1135         /*
1136          * NOTE: relay->source_rt->refs is held by the relay SPAN
1137          *       state, not by this relay structure.
1138          */
1139         relay->conn = NULL;
1140         if (relay->source_rt) {
1141                 dmsg_state_drop(relay->source_rt);
1142                 relay->source_rt = NULL;
1143         }
1144         dmsg_free(relay);
1145 }
1146
1147 /************************************************************************
1148  *                      ROUTER AND MESSAGING HANDLES                    *
1149  ************************************************************************
1150  *
1151  * Basically the idea here is to provide a stable data structure which
1152  * can be localized to the caller for higher level protocols to work with.
1153  * Depends on the context, these dmsg_handle's can be pooled by use-case
1154  * and remain persistent through a client (or mount point's) life.
1155  */
1156
1157 #if 0
1158 /*
1159  * Obtain a stable handle on a cluster given its uuid.  This ties directly
1160  * into the global cluster topology, creating the structure if necessary
1161  * (even if the uuid does not exist or does not exist yet), and preventing
1162  * the structure from getting ripped out from under us while we hold a
1163  * pointer to it.
1164  */
1165 h2span_cluster_t *
1166 dmsg_cluster_get(uuid_t *peer_id)
1167 {
1168         h2span_cluster_t dummy_cls;
1169         h2span_cluster_t *cls;
1170
1171         dummy_cls.peer_id = *peer_id;
1172         pthread_mutex_lock(&cluster_mtx);
1173         cls = RB_FIND(h2span_cluster_tree, &cluster_tree, &dummy_cls);
1174         if (cls)
1175                 ++cls->refs;
1176         pthread_mutex_unlock(&cluster_mtx);
1177         return (cls);
1178 }
1179
1180 void
1181 dmsg_cluster_put(h2span_cluster_t *cls)
1182 {
1183         pthread_mutex_lock(&cluster_mtx);
1184         assert(cls->refs > 0);
1185         --cls->refs;
1186         if (RB_EMPTY(&cls->tree) && cls->refs == 0) {
1187                 RB_REMOVE(h2span_cluster_tree,
1188                           &cluster_tree, cls);
1189                 dmsg_free(cls);
1190         }
1191         pthread_mutex_unlock(&cluster_mtx);
1192 }
1193
1194 /*
1195  * Obtain a stable handle to a specific cluster node given its uuid.
1196  * This handle does NOT lock in the route to the node and is typically
1197  * used as part of the dmsg_handle_*() API to obtain a set of
1198  * stable nodes.
1199  */
1200 h2span_node_t *
1201 dmsg_node_get(h2span_cluster_t *cls, uuid_t *pfs_id)
1202 {
1203 }
1204
1205 #endif
1206
1207 /*
1208  * Dumps the spanning tree
1209  *
1210  * DEBUG ONLY
1211  */
1212 void
1213 dmsg_shell_tree(dmsg_iocom_t *iocom, char *cmdbuf __unused)
1214 {
1215         h2span_cluster_t *cls;
1216         h2span_node_t *node;
1217         h2span_link_t *slink;
1218         h2span_relay_t *relay;
1219         char *uustr = NULL;
1220
1221         pthread_mutex_lock(&cluster_mtx);
1222         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
1223                 dmsg_printf(iocom, "Cluster %s %s (%s)\n",
1224                                   dmsg_peer_type_to_str(cls->peer_type),
1225                                   dmsg_uuid_to_str(&cls->peer_id, &uustr),
1226                                   cls->peer_label);
1227                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1228                         dmsg_printf(iocom, "    Node %02x %s (%s)\n",
1229                                 node->pfs_type,
1230                                 dmsg_uuid_to_str(&node->pfs_id, &uustr),
1231                                 node->pfs_label);
1232                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1233                                 dmsg_printf(iocom,
1234                                             "\tSLink msgid %016jx "
1235                                             "dist=%d via %d\n",
1236                                             (intmax_t)slink->state->msgid,
1237                                             slink->lnk_span.dist,
1238                                             slink->state->iocom->sock_fd);
1239                                 TAILQ_FOREACH(relay, &slink->relayq, entry) {
1240                                         dmsg_printf(iocom,
1241                                             "\t    Relay-out msgid %016jx "
1242                                             "via %d\n",
1243                                             (intmax_t)relay->target_rt->msgid,
1244                                             relay->target_rt->iocom->sock_fd);
1245                                 }
1246                         }
1247                 }
1248         }
1249         pthread_mutex_unlock(&cluster_mtx);
1250         if (uustr)
1251                 free(uustr);
1252 #if 0
1253         TAILQ_FOREACH(conn, &connq, entry) {
1254         }
1255 #endif
1256 }
1257
1258 /*
1259  * DEBUG ONLY
1260  *
1261  * Locate the state representing an incoming LNK_SPAN given its msgid.
1262  */
1263 int
1264 dmsg_debug_findspan(uint64_t msgid, dmsg_state_t **statep)
1265 {
1266         h2span_cluster_t *cls;
1267         h2span_node_t *node;
1268         h2span_link_t *slink;
1269
1270         pthread_mutex_lock(&cluster_mtx);
1271         RB_FOREACH(cls, h2span_cluster_tree, &cluster_tree) {
1272                 RB_FOREACH(node, h2span_node_tree, &cls->tree) {
1273                         RB_FOREACH(slink, h2span_link_tree, &node->tree) {
1274                                 if (slink->state->msgid == msgid) {
1275                                         *statep = slink->state;
1276                                         goto found;
1277                                 }
1278                         }
1279                 }
1280         }
1281         pthread_mutex_unlock(&cluster_mtx);
1282         *statep = NULL;
1283         return(ENOENT);
1284 found:
1285         pthread_mutex_unlock(&cluster_mtx);
1286         return(0);
1287 }
1288
1289 /*
1290  * Random number sub-sort value to add to SPAN rnss fields on relay.
1291  * This allows us to differentiate spans with the same <dist> field
1292  * for relaying purposes.  We must normally limit the number of relays
1293  * for any given SPAN origination but we must also guarantee that a
1294  * symmetric reverse path exists, so we use the rnss field as a sub-sort
1295  * (since there can be thousands or millions if we only match on <dist>),
1296  * and if there STILL too many spans we go past the limit.
1297  */
1298 static
1299 uint32_t
1300 dmsg_rnss(void)
1301 {
1302         if (DMsgRNSS == 0) {
1303                 pthread_mutex_lock(&cluster_mtx);
1304                 while (DMsgRNSS == 0) {
1305                         srandomdev();
1306                         DMsgRNSS = random();
1307                 }
1308                 pthread_mutex_unlock(&cluster_mtx);
1309         }
1310         return(DMsgRNSS);
1311 }