sys/kern/kern_dmsg.c

   1 /*-
   2  * Copyright (c) 2012 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   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  * TODO: txcmd CREATE state is deferred by tx msgq, need to calculate
  36  *       a streaming response.  See subr_diskiocom()'s diskiodone().
  37  */
  38 #include <sys/param.h>
  39 #include <sys/types.h>
  40 #include <sys/kernel.h>
  41 #include <sys/conf.h>
  42 #include <sys/systm.h>
  43 #include <sys/queue.h>
  44 #include <sys/tree.h>
  45 #include <sys/malloc.h>
  46 #include <sys/mount.h>
  47 #include <sys/socket.h>
  48 #include <sys/vnode.h>
  49 #include <sys/sysctl.h>
  50 #include <sys/file.h>
  51 #include <sys/proc.h>
  52 #include <sys/priv.h>
  53 #include <sys/thread.h>
  54 #include <sys/globaldata.h>
  55 #include <sys/limits.h>
  56
  57 #include <sys/dmsg.h>
  58
  59 RB_GENERATE(kdmsg_state_tree, kdmsg_state, rbnode, kdmsg_state_cmp);
  60
  61 SYSCTL_NODE(, OID_AUTO, kdmsg, CTLFLAG_RW, 0, "kdmsg");
  62 static int kdmsg_debug = 1;
  63 SYSCTL_INT(_kdmsg, OID_AUTO, debug, CTLFLAG_RW, &kdmsg_debug, 0,
  64            "Set debug level for kernel dmsg layer");
  65
  66 #define kd_printf(level, ctl, ...)              \
  67         if (kdmsg_debug >= (level)) kprintf("kdmsg: " ctl, __VA_ARGS__)
  68
  69 #define kdio_printf(iocom, level, ctl, ...)      \
  70         if (kdmsg_debug >= (level)) kprintf("kdmsg: " ctl, __VA_ARGS__)
  71
  72 static int kdmsg_msg_receive_handling(kdmsg_msg_t *msg);
  73 static int kdmsg_state_msgrx(kdmsg_msg_t *msg);
  74 static int kdmsg_state_msgtx(kdmsg_msg_t *msg);
  75 static void kdmsg_msg_write_locked(kdmsg_iocom_t *iocom, kdmsg_msg_t *msg);
  76 static void kdmsg_state_cleanuprx(kdmsg_msg_t *msg);
  77 static void kdmsg_state_cleanuptx(kdmsg_msg_t *msg);
  78 static void kdmsg_subq_delete(kdmsg_state_t *state);
  79 static void kdmsg_simulate_failure(kdmsg_state_t *state, int meto, int error);
  80 static void kdmsg_state_abort(kdmsg_state_t *state);
  81 static void kdmsg_state_dying(kdmsg_state_t *state);
  82 static void kdmsg_state_free(kdmsg_state_t *state);
  83
  84 #ifdef KDMSG_DEBUG
  85 #define KDMSG_DEBUG_ARGS        , const char *file, int line
  86 #define kdmsg_state_hold(state) _kdmsg_state_hold(state, __FILE__, __LINE__)
  87 #define kdmsg_state_drop(state) _kdmsg_state_drop(state, __FILE__, __LINE__)
  88 #else
  89 #define KDMSG_DEBUG_ARGS
  90 #define kdmsg_state_hold(state) _kdmsg_state_hold(state)
  91 #define kdmsg_state_drop(state) _kdmsg_state_drop(state)
  92 #endif
  93 static void _kdmsg_state_hold(kdmsg_state_t *state KDMSG_DEBUG_ARGS);
  94 static void _kdmsg_state_drop(kdmsg_state_t *state KDMSG_DEBUG_ARGS);
  95
  96 static void kdmsg_iocom_thread_rd(void *arg);
  97 static void kdmsg_iocom_thread_wr(void *arg);
  98 static int kdmsg_autorxmsg(kdmsg_msg_t *msg);
  99
 100 /*static struct lwkt_token kdmsg_token = LWKT_TOKEN_INITIALIZER(kdmsg_token);*/
 101
 102 /*
 103  * Initialize the roll-up communications structure for a network
 104  * messaging session.  This function does not install the socket.
 105  */
 106 void
 107 kdmsg_iocom_init(kdmsg_iocom_t *iocom, void *handle, uint32_t flags,
 108                  struct malloc_type *mmsg,
 109                  int (*rcvmsg)(kdmsg_msg_t *msg))
 110 {
 111         bzero(iocom, sizeof(*iocom));
 112         iocom->handle = handle;
 113         iocom->mmsg = mmsg;
 114         iocom->rcvmsg = rcvmsg;
 115         iocom->flags = flags;
 116         lockinit(&iocom->msglk, "h2msg", 0, 0);
 117         TAILQ_INIT(&iocom->msgq);
 118         RB_INIT(&iocom->staterd_tree);
 119         RB_INIT(&iocom->statewr_tree);
 120
 121         iocom->state0.iocom = iocom;
 122         iocom->state0.parent = &iocom->state0;
 123         TAILQ_INIT(&iocom->state0.subq);
 124 }
 125
 126 /*
 127  * [Re]connect using the passed file pointer.  The caller must ref the
 128  * fp for us.  We own that ref now.
 129  */
 130 void
 131 kdmsg_iocom_reconnect(kdmsg_iocom_t *iocom, struct file *fp,
 132                       const char *subsysname)
 133 {
 134         /*
 135          * Destroy the current connection
 136          */
 137         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 138         atomic_set_int(&iocom->msg_ctl, KDMSG_CLUSTERCTL_KILLRX);
 139         while (iocom->msgrd_td || iocom->msgwr_td) {
 140                 wakeup(&iocom->msg_ctl);
 141                 lksleep(iocom, &iocom->msglk, 0, "clstrkl", hz);
 142         }
 143
 144         /*
 145          * Drop communications descriptor
 146          */
 147         if (iocom->msg_fp) {
 148                 fdrop(iocom->msg_fp);
 149                 iocom->msg_fp = NULL;
 150         }
 151
 152         /*
 153          * Setup new communications descriptor
 154          */
 155         iocom->msg_ctl = 0;
 156         iocom->msg_fp = fp;
 157         iocom->msg_seq = 0;
 158         iocom->flags &= ~KDMSG_IOCOMF_EXITNOACC;
 159
 160         lwkt_create(kdmsg_iocom_thread_rd, iocom, &iocom->msgrd_td,
 161                     NULL, 0, -1, "%s-msgrd", subsysname);
 162         lwkt_create(kdmsg_iocom_thread_wr, iocom, &iocom->msgwr_td,
 163                     NULL, 0, -1, "%s-msgwr", subsysname);
 164         lockmgr(&iocom->msglk, LK_RELEASE);
 165 }
 166
 167 /*
 168  * Caller sets up iocom->auto_lnk_conn and iocom->auto_lnk_span, then calls
 169  * this function to handle the state machine for LNK_CONN and LNK_SPAN.
 170  */
 171 static int kdmsg_lnk_conn_reply(kdmsg_state_t *state, kdmsg_msg_t *msg);
 172 static int kdmsg_lnk_span_reply(kdmsg_state_t *state, kdmsg_msg_t *msg);
 173
 174 void
 175 kdmsg_iocom_autoinitiate(kdmsg_iocom_t *iocom,
 176                          void (*auto_callback)(kdmsg_msg_t *msg))
 177 {
 178         kdmsg_msg_t *msg;
 179
 180         iocom->auto_callback = auto_callback;
 181
 182         msg = kdmsg_msg_alloc(&iocom->state0,
 183                               DMSG_LNK_CONN | DMSGF_CREATE,
 184                               kdmsg_lnk_conn_reply, NULL);
 185         iocom->auto_lnk_conn.head = msg->any.head;
 186         msg->any.lnk_conn = iocom->auto_lnk_conn;
 187         iocom->conn_state = msg->state;
 188         kdmsg_state_hold(msg->state);   /* iocom->conn_state */
 189         kdmsg_msg_write(msg);
 190 }
 191
 192 static
 193 int
 194 kdmsg_lnk_conn_reply(kdmsg_state_t *state, kdmsg_msg_t *msg)
 195 {
 196         kdmsg_iocom_t *iocom = state->iocom;
 197         kdmsg_msg_t *rmsg;
 198
 199         /*
 200          * Upon receipt of the LNK_CONN acknowledgement initiate an
 201          * automatic SPAN if we were asked to.  Used by e.g. xdisk, but
 202          * not used by HAMMER2 which must manage more than one transmitted
 203          * SPAN.
 204          */
 205         if ((msg->any.head.cmd & DMSGF_CREATE) &&
 206             (iocom->flags & KDMSG_IOCOMF_AUTOTXSPAN)) {
 207                 rmsg = kdmsg_msg_alloc(&iocom->state0,
 208                                        DMSG_LNK_SPAN | DMSGF_CREATE,
 209                                        kdmsg_lnk_span_reply, NULL);
 210                 iocom->auto_lnk_span.head = rmsg->any.head;
 211                 rmsg->any.lnk_span = iocom->auto_lnk_span;
 212                 kdmsg_msg_write(rmsg);
 213         }
 214
 215         /*
 216          * Process shim after the CONN is acknowledged and before the CONN
 217          * transaction is deleted.  For deletions this gives device drivers
 218          * the ability to interlock new operations on the circuit before
 219          * it becomes illegal and panics.
 220          */
 221         if (iocom->auto_callback)
 222                 iocom->auto_callback(msg);
 223
 224         if ((state->txcmd & DMSGF_DELETE) == 0 &&
 225             (msg->any.head.cmd & DMSGF_DELETE)) {
 226                 /*
 227                  * iocom->conn_state has a state ref, drop it when clearing.
 228                  */
 229                 if (iocom->conn_state)
 230                         kdmsg_state_drop(iocom->conn_state);
 231                 iocom->conn_state = NULL;
 232                 kdmsg_msg_reply(msg, 0);
 233         }
 234
 235         return (0);
 236 }
 237
 238 static
 239 int
 240 kdmsg_lnk_span_reply(kdmsg_state_t *state, kdmsg_msg_t *msg)
 241 {
 242         /*
 243          * Be sure to process shim before terminating the SPAN
 244          * transaction.  Gives device drivers the ability to
 245          * interlock new operations on the circuit before it
 246          * becomes illegal and panics.
 247          */
 248         if (state->iocom->auto_callback)
 249                 state->iocom->auto_callback(msg);
 250
 251         if ((state->txcmd & DMSGF_DELETE) == 0 &&
 252             (msg->any.head.cmd & DMSGF_DELETE)) {
 253                 kdmsg_msg_reply(msg, 0);
 254         }
 255         return (0);
 256 }
 257
 258 /*
 259  * Disconnect and clean up
 260  */
 261 void
 262 kdmsg_iocom_uninit(kdmsg_iocom_t *iocom)
 263 {
 264         kdmsg_state_t *state;
 265         kdmsg_msg_t *msg;
 266         int retries;
 267
 268         /*
 269          * Ask the cluster controller to go away by setting
 270          * KILLRX.  Send a PING to get a response to unstick reading
 271          * from the pipe.
 272          *
 273          * After 10 seconds shitcan the pipe and do an unclean shutdown.
 274          */
 275         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 276
 277         atomic_set_int(&iocom->msg_ctl, KDMSG_CLUSTERCTL_KILLRX);
 278         msg = kdmsg_msg_alloc(&iocom->state0, DMSG_LNK_PING, NULL, NULL);
 279         kdmsg_msg_write_locked(iocom, msg);
 280
 281         retries = 10;
 282         while (iocom->msgrd_td || iocom->msgwr_td) {
 283                 wakeup(&iocom->msg_ctl);
 284                 lksleep(iocom, &iocom->msglk, 0, "clstrkl", hz);
 285                 if (--retries == 0 && iocom->msg_fp) {
 286                         kdio_printf(iocom, 0, "%s\n",
 287                                     "iocom_uninit: "
 288                                     "shitcanning unresponsive pipe");
 289                         fp_shutdown(iocom->msg_fp, SHUT_RDWR);
 290                         /* retries allowed to go negative, keep looping */
 291                 }
 292         }
 293
 294         /*
 295          * Cleanup caches
 296          */
 297         if ((state = iocom->freerd_state) != NULL) {
 298                 iocom->freerd_state = NULL;
 299                 kdmsg_state_drop(state);
 300         }
 301
 302         if ((state = iocom->freewr_state) != NULL) {
 303                 iocom->freewr_state = NULL;
 304                 kdmsg_state_drop(state);
 305         }
 306
 307         /*
 308          * Drop communications descriptor
 309          */
 310         if (iocom->msg_fp) {
 311                 fdrop(iocom->msg_fp);
 312                 iocom->msg_fp = NULL;
 313         }
 314         lockmgr(&iocom->msglk, LK_RELEASE);
 315 }
 316
 317 /*
 318  * Cluster controller thread.  Perform messaging functions.  We have one
 319  * thread for the reader and one for the writer.  The writer handles
 320  * shutdown requests (which should break the reader thread).
 321  */
 322 static
 323 void
 324 kdmsg_iocom_thread_rd(void *arg)
 325 {
 326         kdmsg_iocom_t *iocom = arg;
 327         dmsg_hdr_t hdr;
 328         kdmsg_msg_t *msg = NULL;
 329         size_t hbytes;
 330         size_t abytes;
 331         int error = 0;
 332
 333         while ((iocom->msg_ctl & KDMSG_CLUSTERCTL_KILLRX) == 0) {
 334                 /*
 335                  * Retrieve the message from the pipe or socket.
 336                  */
 337                 error = fp_read(iocom->msg_fp, &hdr, sizeof(hdr),
 338                                 NULL, 1, UIO_SYSSPACE);
 339                 if (error)
 340                         break;
 341                 if (hdr.magic != DMSG_HDR_MAGIC) {
 342                         kdio_printf(iocom, 1, "bad magic: %04x\n", hdr.magic);
 343                         error = EINVAL;
 344                         break;
 345                 }
 346                 hbytes = (hdr.cmd & DMSGF_SIZE) * DMSG_ALIGN;
 347                 if (hbytes < sizeof(hdr) || hbytes > DMSG_HDR_MAX) {
 348                         kdio_printf(iocom, 1, "bad header size %zd\n", hbytes);
 349                         error = EINVAL;
 350                         break;
 351                 }
 352
 353                 /* XXX messy: mask cmd to avoid allocating state */
 354                 msg = kdmsg_msg_alloc(&iocom->state0,
 355                                       hdr.cmd & DMSGF_BASECMDMASK,
 356                                       NULL, NULL);
 357                 msg->any.head = hdr;
 358                 msg->hdr_size = hbytes;
 359                 if (hbytes > sizeof(hdr)) {
 360                         error = fp_read(iocom->msg_fp, &msg->any.head + 1,
 361                                         hbytes - sizeof(hdr),
 362                                         NULL, 1, UIO_SYSSPACE);
 363                         if (error) {
 364                                 kdio_printf(iocom, 1, "%s\n",
 365                                             "short msg received");
 366                                 error = EINVAL;
 367                                 break;
 368                         }
 369                 }
 370                 msg->aux_size = hdr.aux_bytes;
 371                 if (msg->aux_size > DMSG_AUX_MAX) {
 372                         kdio_printf(iocom, 1,
 373                                     "illegal msg payload size %zd\n",
 374                                     msg->aux_size);
 375                         error = EINVAL;
 376                         break;
 377                 }
 378                 if (msg->aux_size) {
 379                         abytes = DMSG_DOALIGN(msg->aux_size);
 380                         msg->aux_data = kmalloc(abytes, iocom->mmsg, M_WAITOK);
 381                         msg->flags |= KDMSG_FLAG_AUXALLOC;
 382                         error = fp_read(iocom->msg_fp, msg->aux_data,
 383                                         abytes, NULL, 1, UIO_SYSSPACE);
 384                         if (error) {
 385                                 kdio_printf(iocom, 1, "%s\n",
 386                                             "short msg payload received");
 387                                 break;
 388                         }
 389                 }
 390
 391                 error = kdmsg_msg_receive_handling(msg);
 392                 msg = NULL;
 393         }
 394
 395         kdio_printf(iocom, 1, "read thread terminating error=%d\n", error);
 396
 397         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 398         if (msg)
 399                 kdmsg_msg_free(msg);
 400
 401         /*
 402          * Shutdown the socket and set KILLRX for consistency in case the
 403          * shutdown was not commanded.  Signal the transmit side to shutdown
 404          * by setting KILLTX and waking it up.
 405          */
 406         fp_shutdown(iocom->msg_fp, SHUT_RDWR);
 407         atomic_set_int(&iocom->msg_ctl, KDMSG_CLUSTERCTL_KILLRX |
 408                                         KDMSG_CLUSTERCTL_KILLTX);
 409         iocom->msgrd_td = NULL;
 410         lockmgr(&iocom->msglk, LK_RELEASE);
 411         wakeup(&iocom->msg_ctl);
 412
 413         /*
 414          * iocom can be ripped out at any time once the lock is
 415          * released with msgrd_td set to NULL.  The wakeup()s are safe but
 416          * that is all.
 417          */
 418         wakeup(iocom);
 419         lwkt_exit();
 420 }
 421
 422 static
 423 void
 424 kdmsg_iocom_thread_wr(void *arg)
 425 {
 426         kdmsg_iocom_t *iocom = arg;
 427         kdmsg_msg_t *msg;
 428         ssize_t res;
 429         size_t abytes;
 430         int error = 0;
 431         int save_ticks;
 432         int didwarn;
 433
 434         /*
 435          * Transmit loop
 436          */
 437         msg = NULL;
 438         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 439
 440         while ((iocom->msg_ctl & KDMSG_CLUSTERCTL_KILLTX) == 0 && error == 0) {
 441                 /*
 442                  * Sleep if no messages pending.  Interlock with flag while
 443                  * holding msglk.
 444                  */
 445                 if (TAILQ_EMPTY(&iocom->msgq)) {
 446                         atomic_set_int(&iocom->msg_ctl,
 447                                        KDMSG_CLUSTERCTL_SLEEPING);
 448                         lksleep(&iocom->msg_ctl, &iocom->msglk, 0, "msgwr", hz);
 449                         atomic_clear_int(&iocom->msg_ctl,
 450                                          KDMSG_CLUSTERCTL_SLEEPING);
 451                 }
 452
 453                 while ((msg = TAILQ_FIRST(&iocom->msgq)) != NULL) {
 454                         /*
 455                          * Remove msg from the transmit queue and do
 456                          * persist and half-closed state handling.
 457                          */
 458                         TAILQ_REMOVE(&iocom->msgq, msg, qentry);
 459
 460                         error = kdmsg_state_msgtx(msg);
 461                         if (error == EALREADY) {
 462                                 error = 0;
 463                                 kdmsg_msg_free(msg);
 464                                 continue;
 465                         }
 466                         if (error) {
 467                                 kdmsg_msg_free(msg);
 468                                 break;
 469                         }
 470
 471                         /*
 472                          * Dump the message to the pipe or socket.
 473                          *
 474                          * We have to clean up the message as if the transmit
 475                          * succeeded even if it failed.
 476                          */
 477                         lockmgr(&iocom->msglk, LK_RELEASE);
 478                         error = fp_write(iocom->msg_fp, &msg->any,
 479                                          msg->hdr_size, &res, UIO_SYSSPACE);
 480                         if (error || res != msg->hdr_size) {
 481                                 if (error == 0)
 482                                         error = EINVAL;
 483                                 lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 484                                 kdmsg_state_cleanuptx(msg);
 485                                 break;
 486                         }
 487                         if (msg->aux_size) {
 488                                 abytes = DMSG_DOALIGN(msg->aux_size);
 489                                 error = fp_write(iocom->msg_fp,
 490                                                  msg->aux_data, abytes,
 491                                                  &res, UIO_SYSSPACE);
 492                                 if (error || res != abytes) {
 493                                         if (error == 0)
 494                                                 error = EINVAL;
 495                                         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 496                                         kdmsg_state_cleanuptx(msg);
 497                                         break;
 498                                 }
 499                         }
 500                         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 501                         kdmsg_state_cleanuptx(msg);
 502                 }
 503         }
 504
 505         kdio_printf(iocom, 1, "write thread terminating error=%d\n", error);
 506
 507         /*
 508          * Shutdown the socket and set KILLTX for consistency in case the
 509          * shutdown was not commanded.  Signal the receive side to shutdown
 510          * by setting KILLRX and waking it up.
 511          */
 512         fp_shutdown(iocom->msg_fp, SHUT_RDWR);
 513         atomic_set_int(&iocom->msg_ctl, KDMSG_CLUSTERCTL_KILLRX |
 514                                         KDMSG_CLUSTERCTL_KILLTX);
 515         wakeup(&iocom->msg_ctl);
 516
 517         /*
 518          * The transmit thread is responsible for final cleanups, wait
 519          * for the receive side to terminate to prevent new received
 520          * states from interfering with our cleanup.
 521          *
 522          * Do not set msgwr_td to NULL until we actually exit.
 523          */
 524         while (iocom->msgrd_td) {
 525                 wakeup(&iocom->msg_ctl);
 526                 lksleep(iocom, &iocom->msglk, 0, "clstrkt", hz);
 527         }
 528
 529         /*
 530          * We can no longer receive new messages.  We must drain the transmit
 531          * message queue and simulate received messages to close anay remaining
 532          * states.
 533          *
 534          * Loop until all the states are gone and there are no messages
 535          * pending transmit.
 536          */
 537         save_ticks = ticks;
 538         didwarn = 0;
 539
 540         while (TAILQ_FIRST(&iocom->msgq) ||
 541                RB_ROOT(&iocom->staterd_tree) ||
 542                RB_ROOT(&iocom->statewr_tree)) {
 543                 /*
 544                  * Simulate failure for all sub-states of state0.
 545                  */
 546                 kdmsg_drain_msgq(iocom);
 547                 kdio_printf(iocom, 2, "%s\n",
 548                             "simulate failure for all substates of state0");
 549                 kdmsg_simulate_failure(&iocom->state0, 0, DMSG_ERR_LOSTLINK);
 550
 551                 lksleep(iocom, &iocom->msglk, 0, "clstrtk", hz / 2);
 552
 553                 if ((int)(ticks - save_ticks) > hz*2 && didwarn == 0) {
 554                         didwarn = 1;
 555                         kdio_printf(iocom, 0,
 556                                     "Warning, write thread on %p "
 557                                     "still terminating\n",
 558                                     iocom);
 559                 }
 560                 if ((int)(ticks - save_ticks) > hz*15 && didwarn == 1) {
 561                         didwarn = 2;
 562                         kdio_printf(iocom, 0,
 563                                     "Warning, write thread on %p "
 564                                     "still terminating\n",
 565                                     iocom);
 566                 }
 567                 if ((int)(ticks - save_ticks) > hz*60) {
 568                         kdio_printf(iocom, 0,
 569                                     "Can't terminate: msgq %p "
 570                                     "rd_tree %p wr_tree %p\n",
 571                                     TAILQ_FIRST(&iocom->msgq),
 572                                     RB_ROOT(&iocom->staterd_tree),
 573                                     RB_ROOT(&iocom->statewr_tree));
 574                         lksleep(iocom, &iocom->msglk, 0, "clstrtk", hz * 10);
 575                 }
 576         }
 577
 578         /*
 579          * Exit handling is done by the write thread.
 580          */
 581         iocom->flags |= KDMSG_IOCOMF_EXITNOACC;
 582         lockmgr(&iocom->msglk, LK_RELEASE);
 583
 584         /*
 585          * The state trees had better be empty now
 586          */
 587         KKASSERT(RB_EMPTY(&iocom->staterd_tree));
 588         KKASSERT(RB_EMPTY(&iocom->statewr_tree));
 589         KKASSERT(iocom->conn_state == NULL);
 590
 591         if (iocom->exit_func) {
 592                 /*
 593                  * iocom is invalid after we call the exit function.
 594                  */
 595                 iocom->msgwr_td = NULL;
 596                 iocom->exit_func(iocom);
 597         } else {
 598                 /*
 599                  * iocom can be ripped out from under us once msgwr_td is
 600                  * set to NULL.  The wakeup is safe.
 601                  */
 602                 iocom->msgwr_td = NULL;
 603                 wakeup(iocom);
 604         }
 605         lwkt_exit();
 606 }
 607
 608 /*
 609  * This cleans out the pending transmit message queue, adjusting any
 610  * persistent states properly in the process.
 611  *
 612  * Called with iocom locked.
 613  */
 614 void
 615 kdmsg_drain_msgq(kdmsg_iocom_t *iocom)
 616 {
 617         kdmsg_msg_t *msg;
 618
 619         /*
 620          * Clean out our pending transmit queue, executing the
 621          * appropriate state adjustments.  If this tries to open
 622          * any new outgoing transactions we have to loop up and
 623          * clean them out.
 624          */
 625         while ((msg = TAILQ_FIRST(&iocom->msgq)) != NULL) {
 626                 TAILQ_REMOVE(&iocom->msgq, msg, qentry);
 627                 if (kdmsg_state_msgtx(msg))
 628                         kdmsg_msg_free(msg);
 629                 else
 630                         kdmsg_state_cleanuptx(msg);
 631         }
 632 }
 633
 634 /*
 635  * Do all processing required to handle a freshly received message
 636  * after its low level header has been validated.
 637  *
 638  * iocom is not locked.
 639  */
 640 static
 641 int
 642 kdmsg_msg_receive_handling(kdmsg_msg_t *msg)
 643 {
 644         kdmsg_iocom_t *iocom = msg->state->iocom;
 645         int error;
 646
 647         /*
 648          * State machine tracking, state assignment for msg,
 649          * returns error and discard status.  Errors are fatal
 650          * to the connection except for EALREADY which forces
 651          * a discard without execution.
 652          */
 653         error = kdmsg_state_msgrx(msg);
 654         if (msg->state->flags & KDMSG_STATE_ABORTING) {
 655                 kdio_printf(iocom, 5,
 656                             "kdmsg_state_abort(b): state %p rxcmd=%08x "
 657                             "txcmd=%08x msgrx error %d\n",
 658                             msg->state, msg->state->rxcmd,
 659                             msg->state->txcmd, error);
 660         }
 661         if (error) {
 662                 /*
 663                  * Raw protocol or connection error
 664                  */
 665                 if (msg->state->flags & KDMSG_STATE_ABORTING)
 666                         kdio_printf(iocom, 5,
 667                                     "X1 state %p error %d\n",
 668                                     msg->state, error);
 669                 kdmsg_msg_free(msg);
 670                 if (error == EALREADY)
 671                         error = 0;
 672         } else if (msg->state && msg->state->func) {
 673                 /*
 674                  * Message related to state which already has a
 675                  * handling function installed for it.
 676                  */
 677                 if (msg->state->flags & KDMSG_STATE_ABORTING)
 678                         kdio_printf(iocom, 5,
 679                                     "X2 state %p func %p\n",
 680                                     msg->state, msg->state->func);
 681                 error = msg->state->func(msg->state, msg);
 682                 kdmsg_state_cleanuprx(msg);
 683         } else if (iocom->flags & KDMSG_IOCOMF_AUTOANY) {
 684                 if (msg->state->flags & KDMSG_STATE_ABORTING)
 685                         kdio_printf(iocom, 5,
 686                                     "X3 state %p\n", msg->state);
 687                 error = kdmsg_autorxmsg(msg);
 688                 kdmsg_state_cleanuprx(msg);
 689         } else {
 690                 if (msg->state->flags & KDMSG_STATE_ABORTING)
 691                         kdio_printf(iocom, 5,
 692                                     "X4 state %p\n", msg->state);
 693                 error = iocom->rcvmsg(msg);
 694                 kdmsg_state_cleanuprx(msg);
 695         }
 696         return error;
 697 }
 698
 699 /*
 700  * Process state tracking for a message after reception and dequeueing,
 701  * prior to execution of the state callback.  The state is updated and
 702  * will be removed from the RBTREE if completely closed, but the state->parent
 703  * and subq linkage is not cleaned up until after the callback (see
 704  * cleanuprx()).
 705  *
 706  * msglk is not held.
 707  *
 708  * NOTE: A message transaction can consist of several messages in either
 709  *       direction.
 710  *
 711  * NOTE: The msgid is unique to the initiator, not necessarily unique for
 712  *       us or for any relay or for the return direction for that matter.
 713  *       That is, two sides sending a new message can use the same msgid
 714  *       without colliding.
 715  *
 716  * --
 717  *
 718  * ABORT sequences work by setting the ABORT flag along with normal message
 719  * state.  However, ABORTs can also be sent on half-closed messages, that is
 720  * even if the command or reply side has already sent a DELETE, as long as
 721  * the message has not been fully closed it can still send an ABORT+DELETE
 722  * to terminate the half-closed message state.
 723  *
 724  * Since ABORT+DELETEs can race we silently discard ABORT's for message
 725  * state which has already been fully closed.  REPLY+ABORT+DELETEs can
 726  * also race, and in this situation the other side might have already
 727  * initiated a new unrelated command with the same message id.  Since
 728  * the abort has not set the CREATE flag the situation can be detected
 729   * and the message will also be discarded.
 730  *
 731  * Non-blocking requests can be initiated with ABORT+CREATE[+DELETE].
 732  * The ABORT request is essentially integrated into the command instead
 733  * of being sent later on.  In this situation the command implementation
 734  * detects that CREATE and ABORT are both set (vs ABORT alone) and can
 735  * special-case non-blocking operation for the command.
 736  *
 737  * NOTE!  Messages with ABORT set without CREATE or DELETE are considered
 738  *        to be mid-stream aborts for command/reply sequences.  ABORTs on
 739  *        one-way messages are not supported.
 740  *
 741  * NOTE!  If a command sequence does not support aborts the ABORT flag is
 742  *        simply ignored.
 743  *
 744  * --
 745  *
 746  * One-off messages (no reply expected) are sent with neither CREATE or DELETE
 747  * set.  One-off messages cannot be aborted and typically aren't processed
 748  * by these routines.  The REPLY bit can be used to distinguish whether a
 749  * one-off message is a command or reply.  For example, one-off replies
 750  * will typically just contain status updates.
 751  */
 752 static
 753 int
 754 kdmsg_state_msgrx(kdmsg_msg_t *msg)
 755 {
 756         kdmsg_iocom_t *iocom = msg->state->iocom;
 757         kdmsg_state_t *state;
 758         kdmsg_state_t *pstate;
 759         kdmsg_state_t sdummy;
 760         int error;
 761
 762         /*
 763          * Make sure a state structure is ready to go in case we need a new
 764          * one.  This is the only routine which uses freerd_state so no
 765          * races are possible.
 766          */
 767         if ((state = iocom->freerd_state) == NULL) {
 768                 state = kmalloc(sizeof(*state), iocom->mmsg, M_WAITOK | M_ZERO);
 769                 state->flags = KDMSG_STATE_DYNAMIC;
 770                 state->iocom = iocom;
 771                 state->refs = 1;
 772                 TAILQ_INIT(&state->subq);
 773                 iocom->freerd_state = state;
 774         }
 775         state = NULL;   /* safety */
 776
 777         /*
 778          * Lock RB tree and locate existing persistent state, if any.
 779          *
 780          * If received msg is a command state is on staterd_tree.
 781          * If received msg is a reply state is on statewr_tree.
 782          */
 783         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
 784
 785 again:
 786         if (msg->state == &iocom->state0) {
 787                 sdummy.msgid = msg->any.head.msgid;
 788                 sdummy.iocom = iocom;
 789                 if (msg->any.head.cmd & DMSGF_REVTRANS) {
 790                         state = RB_FIND(kdmsg_state_tree, &iocom->statewr_tree,
 791                                         &sdummy);
 792                 } else {
 793                         state = RB_FIND(kdmsg_state_tree, &iocom->staterd_tree,
 794                                         &sdummy);
 795                 }
 796
 797                 /*
 798                  * Set message state unconditionally.  If this is a CREATE
 799                  * message this state will become the parent state and new
 800                  * state will be allocated for the message state.
 801                  */
 802                 if (state == NULL)
 803                         state = &iocom->state0;
 804                 if (state->flags & KDMSG_STATE_INTERLOCK) {
 805                         state->flags |= KDMSG_STATE_SIGNAL;
 806                         lksleep(state, &iocom->msglk, 0, "dmrace", hz);
 807                         goto again;
 808                 }
 809                 kdmsg_state_hold(state);
 810                 kdmsg_state_drop(msg->state);   /* iocom->state0 */
 811                 msg->state = state;
 812         } else {
 813                 state = msg->state;
 814         }
 815
 816         /*
 817          * Short-cut one-off or mid-stream messages.
 818          */
 819         if ((msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE |
 820                                   DMSGF_ABORT)) == 0) {
 821                 error = 0;
 822                 goto done;
 823         }
 824
 825         /*
 826          * Switch on CREATE, DELETE, REPLY, and also handle ABORT from
 827          * inside the case statements.
 828          */
 829         switch(msg->any.head.cmd & (DMSGF_CREATE|DMSGF_DELETE|DMSGF_REPLY)) {
 830         case DMSGF_CREATE:
 831         case DMSGF_CREATE | DMSGF_DELETE:
 832                 /*
 833                  * New persistant command received.
 834                  */
 835                 if (state != &iocom->state0) {
 836                         kdio_printf(iocom, 1, "%s\n",
 837                                     "duplicate transaction");
 838                         error = EINVAL;
 839                         break;
 840                 }
 841
 842                 /*
 843                  * Lookup the circuit.  The circuit is an open transaction.
 844                  * the REVCIRC bit in the message tells us which side
 845                  * initiated the transaction representing the circuit.
 846                  */
 847                 if (msg->any.head.circuit) {
 848                         sdummy.msgid = msg->any.head.circuit;
 849
 850                         if (msg->any.head.cmd & DMSGF_REVCIRC) {
 851                                 pstate = RB_FIND(kdmsg_state_tree,
 852                                                  &iocom->statewr_tree,
 853                                                  &sdummy);
 854                         } else {
 855                                 pstate = RB_FIND(kdmsg_state_tree,
 856                                                  &iocom->staterd_tree,
 857                                                  &sdummy);
 858                         }
 859                         if (pstate == NULL) {
 860                                 kdio_printf(iocom, 1, "%s\n",
 861                                             "missing parent in "
 862                                             "stacked trans");
 863                                 error = EINVAL;
 864                                 break;
 865                         }
 866                 } else {
 867                         pstate = &iocom->state0;
 868                 }
 869
 870                 /*
 871                  * Allocate new state.
 872                  *
 873                  * msg->state becomes the owner of the ref we inherit from
 874                  * freerd_stae.
 875                  */
 876                 kdmsg_state_drop(state);
 877                 state = iocom->freerd_state;
 878                 iocom->freerd_state = NULL;
 879
 880                 msg->state = state;             /* inherits freerd ref */
 881                 state->parent = pstate;
 882                 KKASSERT(state->iocom == iocom);
 883                 state->flags |= KDMSG_STATE_RBINSERTED |
 884                                 KDMSG_STATE_SUBINSERTED |
 885                                 KDMSG_STATE_OPPOSITE;
 886                 if (TAILQ_EMPTY(&pstate->subq))
 887                         kdmsg_state_hold(pstate);/* states on pstate->subq */
 888                 kdmsg_state_hold(state);        /* state on pstate->subq */
 889                 kdmsg_state_hold(state);        /* state on rbtree */
 890                 state->icmd = msg->any.head.cmd & DMSGF_BASECMDMASK;
 891                 state->rxcmd = msg->any.head.cmd & ~DMSGF_DELETE;
 892                 state->txcmd = DMSGF_REPLY;
 893                 state->msgid = msg->any.head.msgid;
 894                 state->flags &= ~KDMSG_STATE_NEW;
 895                 RB_INSERT(kdmsg_state_tree, &iocom->staterd_tree, state);
 896                 TAILQ_INSERT_TAIL(&pstate->subq, state, entry);
 897                 error = 0;
 898                 break;
 899         case DMSGF_DELETE:
 900                 /*
 901                  * Persistent state is expected but might not exist if an
 902                  * ABORT+DELETE races the close.
 903                  */
 904                 if (state == &iocom->state0) {
 905                         if (msg->any.head.cmd & DMSGF_ABORT) {
 906                                 kdio_printf(iocom, 1, "%s\n",
 907                                             "msgrx: "
 908                                             "state already A");
 909                                 error = EALREADY;
 910                         } else {
 911                                 kdio_printf(iocom, 1, "%s\n",
 912                                             "msgrx: no state for DELETE");
 913                                 error = EINVAL;
 914                         }
 915                         break;
 916                 }
 917
 918                 /*
 919                  * Handle another ABORT+DELETE case if the msgid has already
 920                  * been reused.
 921                  */
 922                 if ((state->rxcmd & DMSGF_CREATE) == 0) {
 923                         if (msg->any.head.cmd & DMSGF_ABORT) {
 924                                 kdio_printf(iocom, 1, "%s\n",
 925                                             "msgrx: state already B");
 926                                 error = EALREADY;
 927                         } else {
 928                                 kdio_printf(iocom, 1, "%s\n",
 929                                             "msgrx: state reused for DELETE");
 930                                 error = EINVAL;
 931                         }
 932                         break;
 933                 }
 934                 error = 0;
 935                 break;
 936         default:
 937                 /*
 938                  * Check for mid-stream ABORT command received, otherwise
 939                  * allow.
 940                  */
 941                 if (msg->any.head.cmd & DMSGF_ABORT) {
 942                         if (state == &iocom->state0 ||
 943                             (state->rxcmd & DMSGF_CREATE) == 0) {
 944                                 error = EALREADY;
 945                                 break;
 946                         }
 947                 }
 948                 error = 0;
 949                 break;
 950         case DMSGF_REPLY | DMSGF_CREATE:
 951         case DMSGF_REPLY | DMSGF_CREATE | DMSGF_DELETE:
 952                 /*
 953                  * When receiving a reply with CREATE set the original
 954                  * persistent state message should already exist.
 955                  */
 956                 if (state == &iocom->state0) {
 957                         kdio_printf(iocom, 1,
 958                                     "msgrx: no state match for "
 959                                     "REPLY cmd=%08x msgid=%016jx\n",
 960                                     msg->any.head.cmd,
 961                                     (intmax_t)msg->any.head.msgid);
 962                         error = EINVAL;
 963                         break;
 964                 }
 965                 state->rxcmd = msg->any.head.cmd & ~DMSGF_DELETE;
 966                 error = 0;
 967                 break;
 968         case DMSGF_REPLY | DMSGF_DELETE:
 969                 /*
 970                  * Received REPLY+ABORT+DELETE in case where msgid has
 971                  * already been fully closed, ignore the message.
 972                  */
 973                 if (state == &iocom->state0) {
 974                         if (msg->any.head.cmd & DMSGF_ABORT) {
 975                                 error = EALREADY;
 976                         } else {
 977                                 kdio_printf(iocom, 1, "%s\n",
 978                                             "msgrx: no state match "
 979                                             "for REPLY|DELETE");
 980                                 error = EINVAL;
 981                         }
 982                         break;
 983                 }
 984
 985                 /*
 986                  * Received REPLY+ABORT+DELETE in case where msgid has
 987                  * already been reused for an unrelated message,
 988                  * ignore the message.
 989                  */
 990                 if ((state->rxcmd & DMSGF_CREATE) == 0) {
 991                         if (msg->any.head.cmd & DMSGF_ABORT) {
 992                                 error = EALREADY;
 993                         } else {
 994                                 kdio_printf(iocom, 1, "%s\n",
 995                                             "msgrx: state reused "
 996                                             "for REPLY|DELETE");
 997                                 error = EINVAL;
 998                         }
 999                         break;
1000                 }
1001                 error = 0;
1002                 break;
1003         case DMSGF_REPLY:
1004                 /*
1005                  * Check for mid-stream ABORT reply received to sent command.
1006                  */
1007                 if (msg->any.head.cmd & DMSGF_ABORT) {
1008                         if (state == &iocom->state0 ||
1009                             (state->rxcmd & DMSGF_CREATE) == 0) {
1010                                 error = EALREADY;
1011                                 break;
1012                         }
1013                 }
1014                 error = 0;
1015                 break;
1016         }
1017
1018         /*
1019          * Calculate the easy-switch() transactional command.  Represents
1020          * the outer-transaction command for any transaction-create or
1021          * transaction-delete, and the inner message command for any
1022          * non-transaction or inside-transaction command.  tcmd will be
1023          * set to 0 if the message state is illegal.
1024          *
1025          * The two can be told apart because outer-transaction commands
1026          * always have a DMSGF_CREATE and/or DMSGF_DELETE flag.
1027          */
1028 done:
1029         if (msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE)) {
1030                 if (state != &iocom->state0) {
1031                         msg->tcmd = (msg->state->icmd & DMSGF_BASECMDMASK) |
1032                                     (msg->any.head.cmd & (DMSGF_CREATE |
1033                                                           DMSGF_DELETE |
1034                                                           DMSGF_REPLY));
1035                 } else {
1036                         msg->tcmd = 0;
1037                 }
1038         } else {
1039                 msg->tcmd = msg->any.head.cmd & DMSGF_CMDSWMASK;
1040         }
1041
1042         /*
1043          * Adjust the state for DELETE handling now, before making the
1044          * callback so we are atomic with other state updates.
1045          *
1046          * Subq/parent linkages are cleaned up after the callback.
1047          * If an error occurred the message is ignored and state is not
1048          * updated.
1049          */
1050         if ((state = msg->state) == NULL || error != 0) {
1051                 kdio_printf(iocom, 1,
1052                             "msgrx: state=%p error %d\n",
1053                             state, error);
1054         } else if (msg->any.head.cmd & DMSGF_DELETE) {
1055                 KKASSERT((state->rxcmd & DMSGF_DELETE) == 0);
1056                 state->rxcmd |= DMSGF_DELETE;
1057                 if (state->txcmd & DMSGF_DELETE) {
1058                         KKASSERT(state->flags & KDMSG_STATE_RBINSERTED);
1059                         if (state->rxcmd & DMSGF_REPLY) {
1060                                 KKASSERT(msg->any.head.cmd &
1061                                          DMSGF_REPLY);
1062                                 RB_REMOVE(kdmsg_state_tree,
1063                                           &iocom->statewr_tree, state);
1064                         } else {
1065                                 KKASSERT((msg->any.head.cmd &
1066                                           DMSGF_REPLY) == 0);
1067                                 RB_REMOVE(kdmsg_state_tree,
1068                                           &iocom->staterd_tree, state);
1069                         }
1070                         state->flags &= ~KDMSG_STATE_RBINSERTED;
1071                         kdmsg_state_drop(state);        /* state on rbtree */
1072                 }
1073         }
1074         lockmgr(&iocom->msglk, LK_RELEASE);
1075
1076         return (error);
1077 }
1078
1079 /*
1080  * Called instead of iocom->rcvmsg() if any of the AUTO flags are set.
1081  * This routine must call iocom->rcvmsg() for anything not automatically
1082  * handled.
1083  */
1084 static int
1085 kdmsg_autorxmsg(kdmsg_msg_t *msg)
1086 {
1087         kdmsg_iocom_t *iocom = msg->state->iocom;
1088         kdmsg_msg_t *rep;
1089         int error = 0;
1090         uint32_t cmd;
1091
1092         /*
1093          * Main switch processes transaction create/delete sequences only.
1094          * Use icmd (DELETEs use DMSG_LNK_ERROR
1095          *
1096          * NOTE: If processing in-transaction messages you generally want
1097          *       an inner switch on msg->any.head.cmd.
1098          */
1099         if (msg->state) {
1100                 cmd = (msg->state->icmd & DMSGF_BASECMDMASK) |
1101                       (msg->any.head.cmd & (DMSGF_CREATE |
1102                                             DMSGF_DELETE |
1103                                             DMSGF_REPLY));
1104         } else {
1105                 cmd = 0;
1106         }
1107
1108         switch(cmd) {
1109         case DMSG_LNK_PING:
1110                 /*
1111                  * Received ping, send reply
1112                  */
1113                 rep = kdmsg_msg_alloc(msg->state, DMSG_LNK_PING | DMSGF_REPLY,
1114                                       NULL, NULL);
1115                 kdmsg_msg_write(rep);
1116                 break;
1117         case DMSG_LNK_PING | DMSGF_REPLY:
1118                 /* ignore replies */
1119                 break;
1120         case DMSG_LNK_CONN | DMSGF_CREATE:
1121         case DMSG_LNK_CONN | DMSGF_CREATE | DMSGF_DELETE:
1122                 /*
1123                  * Received LNK_CONN transaction.  Transmit response and
1124                  * leave transaction open, which allows the other end to
1125                  * start to the SPAN protocol.
1126                  *
1127                  * Handle shim after acknowledging the CONN.
1128                  */
1129                 if ((msg->any.head.cmd & DMSGF_DELETE) == 0) {
1130                         if (iocom->flags & KDMSG_IOCOMF_AUTOCONN) {
1131                                 kdmsg_msg_result(msg, 0);
1132                                 if (iocom->auto_callback)
1133                                         iocom->auto_callback(msg);
1134                         } else {
1135                                 error = iocom->rcvmsg(msg);
1136                         }
1137                         break;
1138                 }
1139                 /* fall through */
1140         case DMSG_LNK_CONN | DMSGF_DELETE:
1141                 /*
1142                  * This message is usually simulated after a link is lost
1143                  * to clean up the transaction.
1144                  */
1145                 if (iocom->flags & KDMSG_IOCOMF_AUTOCONN) {
1146                         if (iocom->auto_callback)
1147                                 iocom->auto_callback(msg);
1148                         kdmsg_msg_reply(msg, 0);
1149                 } else {
1150                         error = iocom->rcvmsg(msg);
1151                 }
1152                 break;
1153         case DMSG_LNK_SPAN | DMSGF_CREATE:
1154         case DMSG_LNK_SPAN | DMSGF_CREATE | DMSGF_DELETE:
1155                 /*
1156                  * Received LNK_SPAN transaction.  We do not have to respond
1157                  * (except on termination), but we must leave the transaction
1158                  * open.
1159                  *
1160                  * Handle shim after acknowledging the SPAN.
1161                  */
1162                 if (iocom->flags & KDMSG_IOCOMF_AUTORXSPAN) {
1163                         if ((msg->any.head.cmd & DMSGF_DELETE) == 0) {
1164                                 if (iocom->auto_callback)
1165                                         iocom->auto_callback(msg);
1166                                 break;
1167                         }
1168                         /* fall through */
1169                 } else {
1170                         error = iocom->rcvmsg(msg);
1171                         break;
1172                 }
1173                 /* fall through */
1174         case DMSG_LNK_SPAN | DMSGF_DELETE:
1175                 /*
1176                  * Process shims (auto_callback) before cleaning up the
1177                  * circuit structure and closing the transactions.  Device
1178                  * driver should ensure that the circuit is not used after
1179                  * the auto_callback() returns.
1180                  *
1181                  * Handle shim before closing the SPAN transaction.
1182                  */
1183                 if (iocom->flags & KDMSG_IOCOMF_AUTORXSPAN) {
1184                         if (iocom->auto_callback)
1185                                 iocom->auto_callback(msg);
1186                         kdmsg_msg_reply(msg, 0);
1187                 } else {
1188                         error = iocom->rcvmsg(msg);
1189                 }
1190                 break;
1191         default:
1192                 /*
1193                  * Anything unhandled goes into rcvmsg.
1194                  *
1195                  * NOTE: Replies to link-level messages initiated by our side
1196                  *       are handled by the state callback, they are NOT
1197                  *       handled here.
1198                  */
1199                 error = iocom->rcvmsg(msg);
1200                 break;
1201         }
1202         return (error);
1203 }
1204
1205 /*
1206  * Post-receive-handling message and state cleanup.  This routine is called
1207  * after the state function handling/callback to properly dispose of the
1208  * message and unlink the state's parent/subq linkage if the state is
1209  * completely closed.
1210  *
1211  * msglk is not held.
1212  */
1213 static
1214 void
1215 kdmsg_state_cleanuprx(kdmsg_msg_t *msg)
1216 {
1217         kdmsg_state_t *state = msg->state;
1218         kdmsg_iocom_t *iocom = state->iocom;
1219
1220         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
1221         if (state != &iocom->state0) {
1222                 /*
1223                  * When terminating a transaction (in either direction), all
1224                  * sub-states are aborted.
1225                  */
1226                 if ((msg->any.head.cmd & DMSGF_DELETE) &&
1227                     TAILQ_FIRST(&msg->state->subq)) {
1228                         kdio_printf(iocom, 2,
1229                                     "simulate failure for substates of "
1230                                     "state %p cmd %08x/%08x\n",
1231                                     msg->state,
1232                                     msg->state->rxcmd,
1233                                     msg->state->txcmd);
1234                         kdmsg_simulate_failure(msg->state,
1235                                                0, DMSG_ERR_LOSTLINK);
1236                 }
1237
1238                 /*
1239                  * Once the state is fully closed we can (try to) remove it
1240                  * from the subq topology.
1241                  */
1242                 if ((state->flags & KDMSG_STATE_SUBINSERTED) &&
1243                     (state->rxcmd & DMSGF_DELETE) &&
1244                     (state->txcmd & DMSGF_DELETE)) {
1245                         /*
1246                          * Remove parent linkage if state is completely closed.
1247                          */
1248                         kdmsg_subq_delete(state);
1249                 }
1250         }
1251         kdmsg_msg_free(msg);
1252
1253         lockmgr(&iocom->msglk, LK_RELEASE);
1254 }
1255
1256 /*
1257  * Remove state from its parent's subq.  This can wind up recursively
1258  * dropping the parent upward.
1259  *
1260  * NOTE: Once we drop the parent, our pstate pointer may become invalid.
1261  */
1262 static
1263 void
1264 kdmsg_subq_delete(kdmsg_state_t *state)
1265 {
1266         kdmsg_state_t *pstate;
1267
1268         if (state->flags & KDMSG_STATE_SUBINSERTED) {
1269                 pstate = state->parent;
1270                 KKASSERT(pstate);
1271                 if (pstate->scan == state)
1272                         pstate->scan = NULL;
1273                 TAILQ_REMOVE(&pstate->subq, state, entry);
1274                 state->flags &= ~KDMSG_STATE_SUBINSERTED;
1275                 state->parent = NULL;
1276                 if (TAILQ_EMPTY(&pstate->subq)) {
1277                         kdmsg_state_drop(pstate);/* pstate->subq */
1278                 }
1279                 pstate = NULL;                   /* safety */
1280                 kdmsg_state_drop(state);         /* pstate->subq */
1281         } else {
1282                 KKASSERT(state->parent == NULL);
1283         }
1284 }
1285
1286 /*
1287  * Simulate receiving a message which terminates an active transaction
1288  * state.  Our simulated received message must set DELETE and may also
1289  * have to set CREATE.  It must also ensure that all fields are set such
1290  * that the receive handling code can find the state (kdmsg_state_msgrx())
1291  * or an endless loop will ensue.
1292  *
1293  * This is used when the other end of the link is dead so the device driver
1294  * gets a completed transaction for all pending states.
1295  *
1296  * Called with iocom locked.
1297  */
1298 static
1299 void
1300 kdmsg_simulate_failure(kdmsg_state_t *state, int meto, int error)
1301 {
1302         kdmsg_state_t *substate;
1303
1304         kdmsg_state_hold(state);                /* aborting */
1305
1306         /*
1307          * Abort parent state first. Parent will not actually disappear
1308          * until children are gone.  Device drivers must handle the situation.
1309          * The advantage of this is that device drivers can flag the situation
1310          * as an interlock against new operations on dying states.  And since
1311          * device operations are often asynchronous anyway, this sequence of
1312          * events works out better.
1313          */
1314         if (meto)
1315                 kdmsg_state_abort(state);
1316
1317         /*
1318          * Recurse through any children.
1319          */
1320 again:
1321         TAILQ_FOREACH(substate, &state->subq, entry) {
1322                 if (substate->flags & KDMSG_STATE_ABORTING)
1323                         continue;
1324                 state->scan = substate;
1325                 kdmsg_simulate_failure(substate, 1, error);
1326                 if (state->scan != substate)
1327                         goto again;
1328         }
1329         kdmsg_state_drop(state);                /* aborting */
1330 }
1331
1332 static
1333 void
1334 kdmsg_state_abort(kdmsg_state_t *state)
1335 {
1336         kdmsg_msg_t *msg;
1337
1338         /*
1339          * Set ABORTING and DYING, return if already set.  If the state was
1340          * just allocated we defer the abort operation until the related
1341          * message is processed.
1342          */
1343         KKASSERT((state->flags & KDMSG_STATE_ABORTING) == 0);
1344         if (state->flags & KDMSG_STATE_ABORTING)
1345                 return;
1346         state->flags |= KDMSG_STATE_ABORTING;
1347         kdmsg_state_dying(state);
1348         if (state->flags & KDMSG_STATE_NEW) {
1349                 kdio_printf(iocom, 5,
1350                             "kdmsg_state_abort(0): state %p rxcmd %08x "
1351                             "txcmd %08x flags %08x - in NEW state\n",
1352                             state, state->rxcmd,
1353                             state->txcmd, state->flags);
1354                 return;
1355         }
1356
1357         /*
1358          * NOTE: The DELETE flag might already be set due to an early
1359          *       termination.
1360          *
1361          * NOTE: Args to kdmsg_msg_alloc() to avoid dynamic state allocation.
1362          *
1363          * NOTE: We are simulating a received message using our state
1364          *       (vs a message generated by the other side using its state),
1365          *       so we must invert DMSGF_REVTRANS and DMSGF_REVCIRC.
1366          */
1367         kdio_printf(iocom, 5,
1368                     "kdmsg_state_abort(1): state %p rxcmd %08x txcmd %08x\n",
1369                     state, state->rxcmd, state->txcmd);
1370         if ((state->rxcmd & DMSGF_DELETE) == 0) {
1371                 msg = kdmsg_msg_alloc(state, DMSG_LNK_ERROR, NULL, NULL);
1372                 if ((state->rxcmd & DMSGF_CREATE) == 0)
1373                         msg->any.head.cmd |= DMSGF_CREATE;
1374                 msg->any.head.cmd |= DMSGF_DELETE |
1375                                      (state->rxcmd & DMSGF_REPLY);
1376                 msg->any.head.cmd ^= (DMSGF_REVTRANS | DMSGF_REVCIRC);
1377                 msg->any.head.error = DMSG_ERR_LOSTLINK;
1378                 kdio_printf(iocom, 5,
1379                             "kdmsg_state_abort(a): state %p msgcmd %08x\n",
1380                             state, msg->any.head.cmd);
1381                 /* circuit not initialized */
1382                 lockmgr(&state->iocom->msglk, LK_RELEASE);
1383                 kdmsg_msg_receive_handling(msg);
1384                 lockmgr(&state->iocom->msglk, LK_EXCLUSIVE);
1385                 msg = NULL;
1386         }
1387         kdio_printf(iocom, 5,
1388                     "kdmsg_state_abort(2): state %p rxcmd %08x txcmd %08x\n",
1389                     state, state->rxcmd, state->txcmd);
1390 }
1391
1392 /*
1393  * Recursively sets KDMSG_STATE_DYING on state and all sub-states, preventing
1394  * the transmission of any new messages on these states.  This is done
1395  * atomically when parent state is terminating, whereas setting ABORTING is
1396  * not atomic and can leak races.
1397  */
1398 static
1399 void
1400 kdmsg_state_dying(kdmsg_state_t *state)
1401 {
1402         kdmsg_state_t *scan;
1403
1404         if ((state->flags & KDMSG_STATE_DYING) == 0) {
1405                 state->flags |= KDMSG_STATE_DYING;
1406                 TAILQ_FOREACH(scan, &state->subq, entry)
1407                         kdmsg_state_dying(scan);
1408         }
1409 }
1410
1411 /*
1412  * Process state tracking for a message prior to transmission.
1413  *
1414  * Called with msglk held and the msg dequeued.  Returns non-zero if
1415  * the message is bad and should be deleted by the caller.
1416  *
1417  * One-off messages are usually with dummy state and msg->state may be NULL
1418  * in this situation.
1419  *
1420  * New transactions (when CREATE is set) will insert the state.
1421  *
1422  * May request that caller discard the message by setting *discardp to 1.
1423  * A NULL state may be returned in this case.
1424  */
1425 static
1426 int
1427 kdmsg_state_msgtx(kdmsg_msg_t *msg)
1428 {
1429         kdmsg_iocom_t *iocom = msg->state->iocom;
1430         kdmsg_state_t *state;
1431         int error;
1432
1433         /*
1434          * Make sure a state structure is ready to go in case we need a new
1435          * one.  This is the only routine which uses freewr_state so no
1436          * races are possible.
1437          */
1438         if ((state = iocom->freewr_state) == NULL) {
1439                 state = kmalloc(sizeof(*state), iocom->mmsg, M_WAITOK | M_ZERO);
1440                 state->flags = KDMSG_STATE_DYNAMIC;
1441                 state->iocom = iocom;
1442                 state->refs = 1;
1443                 TAILQ_INIT(&state->subq);
1444                 iocom->freewr_state = state;
1445         }
1446
1447         /*
1448          * Lock RB tree.  If persistent state is present it will have already
1449          * been assigned to msg.
1450          */
1451         state = msg->state;
1452
1453         /*
1454          * Short-cut one-off or mid-stream messages (state may be NULL).
1455          */
1456         if ((msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE |
1457                                   DMSGF_ABORT)) == 0) {
1458                 return(0);
1459         }
1460
1461
1462         /*
1463          * Switch on CREATE, DELETE, REPLY, and also handle ABORT from
1464          * inside the case statements.
1465          */
1466         switch(msg->any.head.cmd & (DMSGF_CREATE | DMSGF_DELETE |
1467                                     DMSGF_REPLY)) {
1468         case DMSGF_CREATE:
1469         case DMSGF_CREATE | DMSGF_DELETE:
1470                 /*
1471                  * Insert the new persistent message state and mark
1472                  * half-closed if DELETE is set.  Since this is a new
1473                  * message it isn't possible to transition into the fully
1474                  * closed state here.
1475                  *
1476                  * XXX state must be assigned and inserted by
1477                  *     kdmsg_msg_write().  txcmd is assigned by us
1478                  *     on-transmit.
1479                  */
1480                 KKASSERT(state != NULL);
1481                 state->icmd = msg->any.head.cmd & DMSGF_BASECMDMASK;
1482                 state->txcmd = msg->any.head.cmd & ~DMSGF_DELETE;
1483                 state->rxcmd = DMSGF_REPLY;
1484                 state->flags &= ~KDMSG_STATE_NEW;
1485                 error = 0;
1486                 break;
1487         case DMSGF_DELETE:
1488                 /*
1489                  * Sent ABORT+DELETE in case where msgid has already
1490                  * been fully closed, ignore the message.
1491                  */
1492                 if (state == &iocom->state0) {
1493                         if (msg->any.head.cmd & DMSGF_ABORT) {
1494                                 error = EALREADY;
1495                         } else {
1496                                 kdio_printf(iocom, 1,
1497                                         "msgtx: no state match "
1498                                         "for DELETE cmd=%08x msgid=%016jx\n",
1499                                         msg->any.head.cmd,
1500                                         (intmax_t)msg->any.head.msgid);
1501                                 error = EINVAL;
1502                         }
1503                         break;
1504                 }
1505
1506                 /*
1507                  * Sent ABORT+DELETE in case where msgid has
1508                  * already been reused for an unrelated message,
1509                  * ignore the message.
1510                  */
1511                 if ((state->txcmd & DMSGF_CREATE) == 0) {
1512                         if (msg->any.head.cmd & DMSGF_ABORT) {
1513                                 error = EALREADY;
1514                         } else {
1515                                 kdio_printf(iocom, 1, "%s\n",
1516                                             "msgtx: state reused "
1517                                             "for DELETE");
1518                                 error = EINVAL;
1519                         }
1520                         break;
1521                 }
1522                 error = 0;
1523                 break;
1524         default:
1525                 /*
1526                  * Check for mid-stream ABORT command sent
1527                  */
1528                 if (msg->any.head.cmd & DMSGF_ABORT) {
1529                         if (state == &state->iocom->state0 ||
1530                             (state->txcmd & DMSGF_CREATE) == 0) {
1531                                 error = EALREADY;
1532                                 break;
1533                         }
1534                 }
1535                 error = 0;
1536                 break;
1537         case DMSGF_REPLY | DMSGF_CREATE:
1538         case DMSGF_REPLY | DMSGF_CREATE | DMSGF_DELETE:
1539                 /*
1540                  * When transmitting a reply with CREATE set the original
1541                  * persistent state message should already exist.
1542                  */
1543                 if (state == &state->iocom->state0) {
1544                         kdio_printf(iocom, 1, "%s\n",
1545                                     "msgtx: no state match "
1546                                     "for REPLY | CREATE");
1547                         error = EINVAL;
1548                         break;
1549                 }
1550                 state->txcmd = msg->any.head.cmd & ~DMSGF_DELETE;
1551                 error = 0;
1552                 break;
1553         case DMSGF_REPLY | DMSGF_DELETE:
1554                 /*
1555                  * When transmitting a reply with DELETE set the original
1556                  * persistent state message should already exist.
1557                  *
1558                  * This is very similar to the REPLY|CREATE|* case except
1559                  * txcmd is already stored, so we just add the DELETE flag.
1560                  *
1561                  * Sent REPLY+ABORT+DELETE in case where msgid has
1562                  * already been fully closed, ignore the message.
1563                  */
1564                 if (state == &state->iocom->state0) {
1565                         if (msg->any.head.cmd & DMSGF_ABORT) {
1566                                 error = EALREADY;
1567                         } else {
1568                                 kdio_printf(iocom, 1, "%s\n",
1569                                             "msgtx: no state match "
1570                                             "for REPLY | DELETE");
1571                                 error = EINVAL;
1572                         }
1573                         break;
1574                 }
1575
1576                 /*
1577                  * Sent REPLY+ABORT+DELETE in case where msgid has already
1578                  * been reused for an unrelated message, ignore the message.
1579                  */
1580                 if ((state->txcmd & DMSGF_CREATE) == 0) {
1581                         if (msg->any.head.cmd & DMSGF_ABORT) {
1582                                 error = EALREADY;
1583                         } else {
1584                                 kdio_printf(iocom, 1, "%s\n",
1585                                             "msgtx: state reused "
1586                                             "for REPLY | DELETE");
1587                                 error = EINVAL;
1588                         }
1589                         break;
1590                 }
1591                 error = 0;
1592                 break;
1593         case DMSGF_REPLY:
1594                 /*
1595                  * Check for mid-stream ABORT reply sent.
1596                  *
1597                  * One-off REPLY messages are allowed for e.g. status updates.
1598                  */
1599                 if (msg->any.head.cmd & DMSGF_ABORT) {
1600                         if (state == &state->iocom->state0 ||
1601                             (state->txcmd & DMSGF_CREATE) == 0) {
1602                                 error = EALREADY;
1603                                 break;
1604                         }
1605                 }
1606                 error = 0;
1607                 break;
1608         }
1609
1610         /*
1611          * Set interlock (XXX hack) in case the send side blocks and a
1612          * response is returned before kdmsg_state_cleanuptx() can be
1613          * run.
1614          */
1615         if (state && error == 0)
1616                 state->flags |= KDMSG_STATE_INTERLOCK;
1617
1618         return (error);
1619 }
1620
1621 /*
1622  * Called with iocom locked.
1623  */
1624 static
1625 void
1626 kdmsg_state_cleanuptx(kdmsg_msg_t *msg)
1627 {
1628         kdmsg_iocom_t *iocom = msg->state->iocom;
1629         kdmsg_state_t *state;
1630
1631         if ((state = msg->state) == NULL) {
1632                 kdmsg_msg_free(msg);
1633                 return;
1634         }
1635
1636         /*
1637          * Clear interlock (XXX hack) in case the send side blocks and a
1638          * response is returned in the other thread before
1639          * kdmsg_state_cleanuptx() can be run.  We maintain our hold on
1640          * iocom->msglk so we can do this before completing our task.
1641          */
1642         if (state->flags & KDMSG_STATE_SIGNAL) {
1643                 kdio_printf(iocom, 1, "state %p interlock!\n", state);
1644                 wakeup(state);
1645         }
1646         state->flags &= ~(KDMSG_STATE_INTERLOCK | KDMSG_STATE_SIGNAL);
1647         kdmsg_state_hold(state);
1648
1649         if (msg->any.head.cmd & DMSGF_DELETE) {
1650                 KKASSERT((state->txcmd & DMSGF_DELETE) == 0);
1651                 state->txcmd |= DMSGF_DELETE;
1652                 if (state->rxcmd & DMSGF_DELETE) {
1653                         KKASSERT(state->flags & KDMSG_STATE_RBINSERTED);
1654                         if (state->txcmd & DMSGF_REPLY) {
1655                                 KKASSERT(msg->any.head.cmd &
1656                                          DMSGF_REPLY);
1657                                 RB_REMOVE(kdmsg_state_tree,
1658                                           &iocom->staterd_tree, state);
1659                         } else {
1660                                 KKASSERT((msg->any.head.cmd &
1661                                           DMSGF_REPLY) == 0);
1662                                 RB_REMOVE(kdmsg_state_tree,
1663                                           &iocom->statewr_tree, state);
1664                         }
1665                         state->flags &= ~KDMSG_STATE_RBINSERTED;
1666
1667                         /*
1668                          * The subq recursion is used for parent linking and
1669                          * scanning the topology for aborts, we can only
1670                          * remove leafs.  The circuit is effectively dead now,
1671                          * but topology won't be torn down until all of its
1672                          * children have finished/aborted.
1673                          *
1674                          * This is particularly important for end-point
1675                          * devices which might need to access private data
1676                          * in parent states.  Out of order disconnects can
1677                          * occur if an end-point device is processing a
1678                          * message transaction asynchronously because abort
1679                          * requests are basically synchronous and it probably
1680                          * isn't convenient (or possible) for the end-point
1681                          * to abort an asynchronous operation.
1682                          */
1683                         if (TAILQ_EMPTY(&state->subq))
1684                                 kdmsg_subq_delete(state);
1685                         kdmsg_msg_free(msg);
1686                         kdmsg_state_drop(state);   /* state on rbtree */
1687                 } else {
1688                         kdmsg_msg_free(msg);
1689                 }
1690         } else {
1691                 kdmsg_msg_free(msg);
1692         }
1693
1694         /*
1695          * Deferred abort after transmission.
1696          */
1697         if ((state->flags & (KDMSG_STATE_ABORTING | KDMSG_STATE_DYING)) &&
1698             (state->rxcmd & DMSGF_DELETE) == 0) {
1699                 kdio_printf(iocom, 5,
1700                             "kdmsg_state_cleanuptx: state=%p "
1701                             "executing deferred abort\n",
1702                             state);
1703                 state->flags &= ~KDMSG_STATE_ABORTING;
1704                 kdmsg_state_abort(state);
1705         }
1706         kdmsg_state_drop(state);
1707 }
1708
1709 static
1710 void
1711 _kdmsg_state_hold(kdmsg_state_t *state KDMSG_DEBUG_ARGS)
1712 {
1713         atomic_add_int(&state->refs, 1);
1714 #if KDMSG_DEBUG
1715         kd_printf(4, "state %p +%d\t%s:%d\n", state, state->refs, file, line);
1716 #endif
1717 }
1718
1719 static
1720 void
1721 _kdmsg_state_drop(kdmsg_state_t *state KDMSG_DEBUG_ARGS)
1722 {
1723         KKASSERT(state->refs > 0);
1724 #if KDMSG_DEBUG
1725         kd_printf(4, "state %p -%d\t%s:%d\n", state, state->refs, file, line);
1726 #endif
1727         if (atomic_fetchadd_int(&state->refs, -1) == 1)
1728                 kdmsg_state_free(state);
1729 }
1730
1731 static
1732 void
1733 kdmsg_state_free(kdmsg_state_t *state)
1734 {
1735         kdmsg_iocom_t *iocom = state->iocom;
1736
1737         KKASSERT((state->flags & KDMSG_STATE_RBINSERTED) == 0);
1738         KKASSERT((state->flags & KDMSG_STATE_SUBINSERTED) == 0);
1739         KKASSERT(TAILQ_EMPTY(&state->subq));
1740
1741         if (state != &state->iocom->state0)
1742                 kfree(state, iocom->mmsg);
1743 }
1744
1745 kdmsg_msg_t *
1746 kdmsg_msg_alloc(kdmsg_state_t *state, uint32_t cmd,
1747                 int (*func)(kdmsg_state_t *, kdmsg_msg_t *), void *data)
1748 {
1749         kdmsg_iocom_t *iocom = state->iocom;
1750         kdmsg_state_t *pstate;
1751         kdmsg_msg_t *msg;
1752         size_t hbytes;
1753
1754         KKASSERT(iocom != NULL);
1755         hbytes = (cmd & DMSGF_SIZE) * DMSG_ALIGN;
1756         msg = kmalloc(offsetof(struct kdmsg_msg, any) + hbytes,
1757                       iocom->mmsg, M_WAITOK | M_ZERO);
1758         msg->hdr_size = hbytes;
1759
1760         if ((cmd & (DMSGF_CREATE | DMSGF_REPLY)) == DMSGF_CREATE) {
1761                 /*
1762                  * New transaction, requires tracking state and a unique
1763                  * msgid to be allocated.
1764                  *
1765                  * It is possible to race a circuit failure, inherit the
1766                  * parent's STATE_DYING flag to trigger an abort sequence
1767                  * in the transmit path.  By not inheriting ABORTING the
1768                  * abort sequence can recurse.
1769                  *
1770                  * NOTE: The transactions has not yet been initiated so we
1771                  *       cannot set DMSGF_CREATE/DELETE bits in txcmd or rxcmd.
1772                  *       We have to properly setup DMSGF_REPLY, however.
1773                  */
1774                 pstate = state;
1775                 state = kmalloc(sizeof(*state), iocom->mmsg, M_WAITOK | M_ZERO);
1776                 TAILQ_INIT(&state->subq);
1777                 state->iocom = iocom;
1778                 state->parent = pstate;
1779                 state->flags = KDMSG_STATE_DYNAMIC |
1780                                KDMSG_STATE_NEW;
1781                 state->func = func;
1782                 state->any.any = data;
1783                 state->msgid = (uint64_t)(uintptr_t)state;
1784                 /*msg->any.head.msgid = state->msgid;XXX*/
1785
1786                 lockmgr(&iocom->msglk, LK_EXCLUSIVE);
1787                 if (RB_INSERT(kdmsg_state_tree, &iocom->statewr_tree, state))
1788                         panic("duplicate msgid allocated");
1789                 if (TAILQ_EMPTY(&pstate->subq))
1790                         kdmsg_state_hold(pstate);/* pstate->subq */
1791                 TAILQ_INSERT_TAIL(&pstate->subq, state, entry);
1792                 state->flags |= KDMSG_STATE_RBINSERTED |
1793                                 KDMSG_STATE_SUBINSERTED;
1794                 state->flags |= pstate->flags & KDMSG_STATE_DYING;
1795                 kdmsg_state_hold(state);        /* pstate->subq */
1796                 kdmsg_state_hold(state);        /* state on rbtree */
1797                 kdmsg_state_hold(state);        /* msg->state */
1798                 lockmgr(&iocom->msglk, LK_RELEASE);
1799         } else {
1800                 pstate = state->parent;
1801                 KKASSERT(pstate != NULL);
1802                 kdmsg_state_hold(state);        /* msg->state */
1803         }
1804
1805         if (state->flags & KDMSG_STATE_OPPOSITE)
1806                 cmd |= DMSGF_REVTRANS;
1807         if (pstate->flags & KDMSG_STATE_OPPOSITE)
1808                 cmd |= DMSGF_REVCIRC;
1809
1810         msg->any.head.magic = DMSG_HDR_MAGIC;
1811         msg->any.head.cmd = cmd;
1812         msg->any.head.msgid = state->msgid;
1813         msg->any.head.circuit = pstate->msgid;
1814         msg->state = state;
1815
1816         return (msg);
1817 }
1818
1819 void
1820 kdmsg_msg_free(kdmsg_msg_t *msg)
1821 {
1822         kdmsg_iocom_t *iocom = msg->state->iocom;
1823         kdmsg_state_t *state;
1824
1825         if ((msg->flags & KDMSG_FLAG_AUXALLOC) &&
1826             msg->aux_data && msg->aux_size) {
1827                 kfree(msg->aux_data, iocom->mmsg);
1828                 msg->flags &= ~KDMSG_FLAG_AUXALLOC;
1829         }
1830         if ((state = msg->state) != NULL) {
1831                 msg->state = NULL;
1832                 kdmsg_state_drop(state);        /* msg->state */
1833         }
1834         msg->aux_data = NULL;
1835         msg->aux_size = 0;
1836
1837         kfree(msg, iocom->mmsg);
1838 }
1839
1840 void
1841 kdmsg_detach_aux_data(kdmsg_msg_t *msg, kdmsg_data_t *data)
1842 {
1843         if (msg->flags & KDMSG_FLAG_AUXALLOC) {
1844                 data->aux_data = msg->aux_data;
1845                 data->aux_size = msg->aux_size;
1846                 data->iocom = msg->state->iocom;
1847                 msg->flags &= ~KDMSG_FLAG_AUXALLOC;
1848         } else {
1849                 data->aux_data = NULL;
1850                 data->aux_size = 0;
1851                 data->iocom = msg->state->iocom;
1852         }
1853 }
1854
1855 void
1856 kdmsg_free_aux_data(kdmsg_data_t *data)
1857 {
1858         if (data->aux_data)
1859                 kfree(data->aux_data, data->iocom->mmsg);
1860 }
1861
1862 /*
1863  * Indexed messages are stored in a red-black tree indexed by their
1864  * msgid.  Only persistent messages are indexed.
1865  */
1866 int
1867 kdmsg_state_cmp(kdmsg_state_t *state1, kdmsg_state_t *state2)
1868 {
1869         if (state1->iocom < state2->iocom)
1870                 return(-1);
1871         if (state1->iocom > state2->iocom)
1872                 return(1);
1873         if (state1->msgid < state2->msgid)
1874                 return(-1);
1875         if (state1->msgid > state2->msgid)
1876                 return(1);
1877         return(0);
1878 }
1879
1880 /*
1881  * Write a message.  All requisit command flags have been set.
1882  *
1883  * If msg->state is non-NULL the message is written to the existing
1884  * transaction.  msgid will be set accordingly.
1885  *
1886  * If msg->state is NULL and CREATE is set new state is allocated and
1887  * (func, data) is installed.  A msgid is assigned.
1888  *
1889  * If msg->state is NULL and CREATE is not set the message is assumed
1890  * to be a one-way message.  The originator must assign the msgid
1891  * (or leave it 0, which is typical.
1892  *
1893  * This function merely queues the message to the management thread, it
1894  * does not write to the message socket/pipe.
1895  */
1896 void
1897 kdmsg_msg_write(kdmsg_msg_t *msg)
1898 {
1899         kdmsg_iocom_t *iocom = msg->state->iocom;
1900
1901         lockmgr(&iocom->msglk, LK_EXCLUSIVE);
1902         kdmsg_msg_write_locked(iocom, msg);
1903         lockmgr(&iocom->msglk, LK_RELEASE);
1904 }
1905
1906 static void
1907 kdmsg_msg_write_locked(kdmsg_iocom_t *iocom, kdmsg_msg_t *msg)
1908 {
1909         kdmsg_state_t *state;
1910
1911         if (msg->state) {
1912                 /*
1913                  * Continuance or termination of existing transaction.
1914                  * The transaction could have been initiated by either end.
1915                  *
1916                  * (Function callback and aux data for the receive side can
1917                  * be replaced or left alone).
1918                  */
1919                 state = msg->state;
1920                 msg->any.head.msgid = state->msgid;
1921         } else {
1922                 /*
1923                  * One-off message (always uses msgid 0 to distinguish
1924                  * between a possibly lost in-transaction message due to
1925                  * competing aborts and a real one-off message?)
1926                  */
1927                 state = NULL;
1928                 msg->any.head.msgid = 0;
1929         }
1930
1931 #if 0
1932         /*
1933          * XXX removed - don't make this a panic, allow the state checks
1934          *     below to catch the situation.
1935          *
1936          * This flag is not set until after the tx thread has drained
1937          * the tx msgq and simulated responses.  After that point the
1938          * txthread is dead and can no longer simulate responses.
1939          *
1940          * Device drivers should never try to send a message once this
1941          * flag is set.  They should have detected (through the state
1942          * closures) that the link is in trouble.
1943          */
1944         if (iocom->flags & KDMSG_IOCOMF_EXITNOACC) {
1945                 lockmgr(&iocom->msglk, LK_RELEASE);
1946                 panic("kdmsg_msg_write: Attempt to write message to "
1947                       "terminated iocom\n");
1948         }
1949 #endif
1950
1951         /*
1952          * For stateful messages, if the circuit is dead or dying we have
1953          * to abort the potentially newly-created state and discard the
1954          * message.
1955          *
1956          * - We must discard the message because the other end will not
1957          *   be expecting any more messages over the dead or dying circuit
1958          *   and might not be able to receive them.
1959          *
1960          * - We abort the state by simulating a failure to generate a fake
1961          *   incoming DELETE.  This will trigger the state callback and allow
1962          *   the device to clean things up and reply, closing the outgoing
1963          *   direction and allowing the state to be freed.
1964          *
1965          * This situation occurs quite often, particularly as SPANs stabilize.
1966          * End-points must do the right thing.
1967          */
1968         if (state) {
1969                 KKASSERT((state->txcmd & DMSGF_DELETE) == 0);
1970                 if (state->flags & KDMSG_STATE_DYING) {
1971 #if 0
1972                 if ((state->flags & KDMSG_STATE_DYING) ||
1973                     (state->parent->txcmd & DMSGF_DELETE) ||
1974                     (state->parent->flags & KDMSG_STATE_DYING)) {
1975 #endif
1976                         kdio_printf(iocom, 4,
1977                                     "kdmsg_msg_write: Write to dying circuit "
1978                                     "state=%p "
1979                                     "ptxcmd=%08x prxcmd=%08x flags=%08x\n",
1980                                     state,
1981                                     state->parent->rxcmd,
1982                                     state->parent->txcmd,
1983                                     state->parent->flags);
1984                         kdmsg_state_hold(state);
1985                         kdmsg_state_msgtx(msg);
1986                         kdmsg_state_cleanuptx(msg);
1987                         kdmsg_state_drop(state);
1988                         return;
1989                 }
1990         }
1991
1992         /*
1993          * Finish up the msg fields.  Note that msg->aux_size and the
1994          * aux_bytes stored in the message header represent the unaligned
1995          * (actual) bytes of data, but the buffer is sized to an aligned
1996          * size and the CRC is generated over the aligned length.
1997          */
1998         msg->any.head.salt = /* (random << 8) | */ (iocom->msg_seq & 255);
1999         ++iocom->msg_seq;
2000
2001         if (msg->aux_data && msg->aux_size) {
2002                 uint32_t abytes = DMSG_DOALIGN(msg->aux_size);
2003
2004                 msg->any.head.aux_bytes = msg->aux_size;
2005                 msg->any.head.aux_crc = iscsi_crc32(msg->aux_data, abytes);
2006         }
2007         msg->any.head.hdr_crc = 0;
2008         msg->any.head.hdr_crc = iscsi_crc32(msg->any.buf, msg->hdr_size);
2009
2010         TAILQ_INSERT_TAIL(&iocom->msgq, msg, qentry);
2011
2012         if (iocom->msg_ctl & KDMSG_CLUSTERCTL_SLEEPING) {
2013                 atomic_clear_int(&iocom->msg_ctl,
2014                                  KDMSG_CLUSTERCTL_SLEEPING);
2015                 wakeup(&iocom->msg_ctl);
2016         }
2017 }
2018
2019 /*
2020  * Reply to a message and terminate our side of the transaction.
2021  *
2022  * If msg->state is non-NULL we are replying to a one-way message.
2023  */
2024 void
2025 kdmsg_msg_reply(kdmsg_msg_t *msg, uint32_t error)
2026 {
2027         kdmsg_state_t *state = msg->state;
2028         kdmsg_msg_t *nmsg;
2029         uint32_t cmd;
2030
2031         /*
2032          * Reply with a simple error code and terminate the transaction.
2033          */
2034         cmd = DMSG_LNK_ERROR;
2035
2036         /*
2037          * Check if our direction has even been initiated yet, set CREATE.
2038          *
2039          * Check what direction this is (command or reply direction).  Note
2040          * that txcmd might not have been initiated yet.
2041          *
2042          * If our direction has already been closed we just return without
2043          * doing anything.
2044          */
2045         if (state != &state->iocom->state0) {
2046                 if (state->txcmd & DMSGF_DELETE)
2047                         return;
2048                 if ((state->txcmd & DMSGF_CREATE) == 0)
2049                         cmd |= DMSGF_CREATE;
2050                 if (state->txcmd & DMSGF_REPLY)
2051                         cmd |= DMSGF_REPLY;
2052                 cmd |= DMSGF_DELETE;
2053         } else {
2054                 if ((msg->any.head.cmd & DMSGF_REPLY) == 0)
2055                         cmd |= DMSGF_REPLY;
2056         }
2057
2058         nmsg = kdmsg_msg_alloc(state, cmd, NULL, NULL);
2059         nmsg->any.head.error = error;
2060         kdmsg_msg_write(nmsg);
2061 }
2062
2063 /*
2064  * Reply to a message and continue our side of the transaction.
2065  *
2066  * If msg->state is non-NULL we are replying to a one-way message and this
2067  * function degenerates into the same as kdmsg_msg_reply().
2068  */
2069 void
2070 kdmsg_msg_result(kdmsg_msg_t *msg, uint32_t error)
2071 {
2072         kdmsg_state_t *state = msg->state;
2073         kdmsg_msg_t *nmsg;
2074         uint32_t cmd;
2075
2076         /*
2077          * Return a simple result code, do NOT terminate the transaction.
2078          */
2079         cmd = DMSG_LNK_ERROR;
2080
2081         /*
2082          * Check if our direction has even been initiated yet, set CREATE.
2083          *
2084          * Check what direction this is (command or reply direction).  Note
2085          * that txcmd might not have been initiated yet.
2086          *
2087          * If our direction has already been closed we just return without
2088          * doing anything.
2089          */
2090         if (state != &state->iocom->state0) {
2091                 if (state->txcmd & DMSGF_DELETE)
2092                         return;
2093                 if ((state->txcmd & DMSGF_CREATE) == 0)
2094                         cmd |= DMSGF_CREATE;
2095                 if (state->txcmd & DMSGF_REPLY)
2096                         cmd |= DMSGF_REPLY;
2097                 /* continuing transaction, do not set MSGF_DELETE */
2098         } else {
2099                 if ((msg->any.head.cmd & DMSGF_REPLY) == 0)
2100                         cmd |= DMSGF_REPLY;
2101         }
2102
2103         nmsg = kdmsg_msg_alloc(state, cmd, NULL, NULL);
2104         nmsg->any.head.error = error;
2105         kdmsg_msg_write(nmsg);
2106 }
2107
2108 /*
2109  * Reply to a message and terminate our side of the transaction.
2110  *
2111  * If msg->state is non-NULL we are replying to a one-way message.
2112  */
2113 void
2114 kdmsg_state_reply(kdmsg_state_t *state, uint32_t error)
2115 {
2116         kdmsg_msg_t *nmsg;
2117         uint32_t cmd;
2118
2119         /*
2120          * Reply with a simple error code and terminate the transaction.
2121          */
2122         cmd = DMSG_LNK_ERROR;
2123
2124         /*
2125          * Check if our direction has even been initiated yet, set CREATE.
2126          *
2127          * Check what direction this is (command or reply direction).  Note
2128          * that txcmd might not have been initiated yet.
2129          *
2130          * If our direction has already been closed we just return without
2131          * doing anything.
2132          */
2133         KKASSERT(state);
2134         if (state->txcmd & DMSGF_DELETE)
2135                 return;
2136         if ((state->txcmd & DMSGF_CREATE) == 0)
2137                 cmd |= DMSGF_CREATE;
2138         if (state->txcmd & DMSGF_REPLY)
2139                 cmd |= DMSGF_REPLY;
2140         cmd |= DMSGF_DELETE;
2141
2142         nmsg = kdmsg_msg_alloc(state, cmd, NULL, NULL);
2143         nmsg->any.head.error = error;
2144         kdmsg_msg_write(nmsg);
2145 }
2146
2147 /*
2148  * Reply to a message and continue our side of the transaction.
2149  *
2150  * If msg->state is non-NULL we are replying to a one-way message and this
2151  * function degenerates into the same as kdmsg_msg_reply().
2152  */
2153 void
2154 kdmsg_state_result(kdmsg_state_t *state, uint32_t error)
2155 {
2156         kdmsg_msg_t *nmsg;
2157         uint32_t cmd;
2158
2159         /*
2160          * Return a simple result code, do NOT terminate the transaction.
2161          */
2162         cmd = DMSG_LNK_ERROR;
2163
2164         /*
2165          * Check if our direction has even been initiated yet, set CREATE.
2166          *
2167          * Check what direction this is (command or reply direction).  Note
2168          * that txcmd might not have been initiated yet.
2169          *
2170          * If our direction has already been closed we just return without
2171          * doing anything.
2172          */
2173         KKASSERT(state);
2174         if (state->txcmd & DMSGF_DELETE)
2175                 return;
2176         if ((state->txcmd & DMSGF_CREATE) == 0)
2177                 cmd |= DMSGF_CREATE;
2178         if (state->txcmd & DMSGF_REPLY)
2179                 cmd |= DMSGF_REPLY;
2180         /* continuing transaction, do not set MSGF_DELETE */
2181
2182         nmsg = kdmsg_msg_alloc(state, cmd, NULL, NULL);
2183         nmsg->any.head.error = error;
2184         kdmsg_msg_write(nmsg);
2185 }