sys/netgraph/tty/ng_tty.c

   1 /*
   2  * (MPSAFE)
   3  *
   4  * ng_tty.c
   5  *
   6  * Copyright (c) 1996-1999 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Archie Cobbs <archie@freebsd.org>
  39  *
  40  * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 dillon Exp $
  41  * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
  42  */
  43
  44 /*
  45  * This file implements a terminal line discipline that is also a
  46  * netgraph node. Installing this line discipline on a terminal device
  47  * instantiates a new netgraph node of this type, which allows access
  48  * to the device via the "hook" hook of the node.
  49  *
  50  * Once the line discipline is installed, you can find out the name
  51  * of the corresponding netgraph node via a NGIOCGINFO ioctl().
  52  *
  53  * Incoming characters are delievered to the hook one at a time, each
  54  * in its own mbuf. You may optionally define a ``hotchar,'' which causes
  55  * incoming characters to be buffered up until either the hotchar is
  56  * seen or the mbuf is full (MHLEN bytes). Then all buffered characters
  57  * are immediately delivered.
  58  *
  59  * NOTE: This node operates at spltty().
  60  */
  61
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/kernel.h>
  65 #include <sys/conf.h>
  66 #include <sys/proc.h>
  67 #include <sys/caps.h>
  68 #include <sys/mbuf.h>
  69 #include <sys/malloc.h>
  70 #include <sys/fcntl.h>
  71 #include <sys/tty.h>
  72 #include <sys/ttycom.h>
  73 #include <sys/syslog.h>
  74 #include <sys/errno.h>
  75
  76 #include <netgraph/ng_message.h>
  77 #include <netgraph/netgraph.h>
  78 #include "ng_tty.h"
  79
  80 /* Misc defs */
  81 #define MAX_MBUFQ               3       /* Max number of queued mbufs */
  82 #define NGT_HIWATER             400     /* High water mark on output */
  83
  84 /* Per-node private info */
  85 struct ngt_sc {
  86         struct  tty *tp;                /* Terminal device */
  87         node_p  node;                   /* Netgraph node */
  88         hook_p  hook;                   /* Netgraph hook */
  89         struct  mbuf *m;                /* Incoming data buffer */
  90         struct  mbuf *qhead, **qtail;   /* Queue of outgoing mbuf's */
  91         short   qlen;                   /* Length of queue */
  92         short   hotchar;                /* Hotchar, or -1 if none */
  93         u_int   flags;                  /* Flags */
  94         struct  callout ctimeout;       /* See man timeout(9) */
  95 };
  96 typedef struct ngt_sc *sc_p;
  97
  98 /* Flags */
  99 #define FLG_TIMEOUT             0x0001  /* A timeout is pending */
 100 #define FLG_DEBUG               0x0002
 101
 102 /* Debugging */
 103 #ifdef INVARIANTS
 104 #define QUEUECHECK(sc)                                                  \
 105     do {                                                                \
 106       struct mbuf       **mp;                                           \
 107       int               k;                                              \
 108                                                                         \
 109       for (k = 0, mp = &sc->qhead;                                      \
 110         k <= MAX_MBUFQ && *mp;                                          \
 111         k++, mp = &(*mp)->m_nextpkt);                                   \
 112       if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail)     \
 113         panic("%s: queue", __func__);                           \
 114     } while (0)
 115 #else
 116 #define QUEUECHECK(sc)  do {} while (0)
 117 #endif
 118
 119 /* Line discipline methods */
 120 static int      ngt_open(cdev_t dev, struct tty *tp);
 121 static int      ngt_close(struct tty *tp, int flag);
 122 static int      ngt_read(struct tty *tp, struct uio *uio, int flag);
 123 static int      ngt_write(struct tty *tp, struct uio *uio, int flag);
 124 static int      ngt_tioctl(struct tty *tp,
 125                     u_long cmd, caddr_t data, int flag, struct ucred *cred);
 126 static int      ngt_input(int c, struct tty *tp);
 127 static int      ngt_start(struct tty *tp);
 128
 129 /* Netgraph methods */
 130 static ng_constructor_t ngt_constructor;
 131 static ng_rcvmsg_t      ngt_rcvmsg;
 132 static ng_shutdown_t    ngt_shutdown;
 133 static ng_newhook_t     ngt_newhook;
 134 static ng_rcvdata_t     ngt_rcvdata;
 135 static ng_disconnect_t  ngt_disconnect;
 136 static int      ngt_mod_event(module_t mod, int event, void *data);
 137
 138 /* Other stuff */
 139 static void     ngt_timeout(void *arg);
 140
 141 #define ERROUT(x)               do { error = (x); goto done; } while (0)
 142
 143 /* Line discipline descriptor */
 144 static struct linesw ngt_disc = {
 145         ngt_open,
 146         ngt_close,
 147         ngt_read,
 148         ngt_write,
 149         ngt_tioctl,
 150         ngt_input,
 151         ngt_start,
 152         ttymodem,
 153         NG_TTY_DFL_HOTCHAR      /* XXX can't change this in serial driver */
 154 };
 155
 156 /* Netgraph node type descriptor */
 157 static struct ng_type typestruct = {
 158         NG_VERSION,
 159         NG_TTY_NODE_TYPE,
 160         ngt_mod_event,
 161         ngt_constructor,
 162         ngt_rcvmsg,
 163         ngt_shutdown,
 164         ngt_newhook,
 165         NULL,
 166         NULL,
 167         ngt_rcvdata,
 168         ngt_rcvdata,
 169         ngt_disconnect,
 170         NULL
 171 };
 172 NETGRAPH_INIT(tty, &typestruct);
 173
 174 static int ngt_unit;
 175 static int ngt_nodeop_ok;       /* OK to create/remove node */
 176 static int ngt_ldisc;
 177
 178 /******************************************************************
 179                     LINE DISCIPLINE METHODS
 180 ******************************************************************/
 181
 182 /*
 183  * Set our line discipline on the tty.
 184  * Called from device open routine or ttioctl() at >= splsofttty()
 185  */
 186 static int
 187 ngt_open(cdev_t dev, struct tty *tp)
 188 {
 189         char name[sizeof(NG_TTY_NODE_TYPE) + 8];
 190         sc_p sc;
 191         int error;
 192
 193         /* Super-user only */
 194         if ((error = caps_priv_check_self(SYSCAP_RESTRICTEDROOT)))
 195                 return (error);
 196         lwkt_gettoken(&tp->t_token);
 197
 198         /* Already installed? */
 199         if (tp->t_line == NETGRAPHDISC) {
 200                 sc = (sc_p) tp->t_sc;
 201                 if (sc != NULL && sc->tp == tp)
 202                         goto done;
 203         }
 204
 205         /* Initialize private struct */
 206         sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
 207         sc->tp = tp;
 208         sc->hotchar = NG_TTY_DFL_HOTCHAR;
 209         sc->qtail = &sc->qhead;
 210         QUEUECHECK(sc);
 211         callout_init_mp(&sc->ctimeout);
 212
 213         /* Setup netgraph node */
 214         ngt_nodeop_ok = 1;
 215         error = ng_make_node_common(&typestruct, &sc->node);
 216         ngt_nodeop_ok = 0;
 217         if (error) {
 218                 kfree(sc, M_NETGRAPH);
 219                 goto done;
 220         }
 221         ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
 222
 223         /* Set back pointers */
 224         sc->node->private = sc;
 225         tp->t_sc = (caddr_t) sc;
 226
 227         /* Assign node its name */
 228         if ((error = ng_name_node(sc->node, name))) {
 229                 log(LOG_ERR, "%s: node name exists?\n", name);
 230                 ngt_nodeop_ok = 1;
 231                 ng_rmnode(sc->node);
 232                 ngt_nodeop_ok = 0;
 233                 goto done;
 234         }
 235
 236         /*
 237          * Pre-allocate cblocks to the an appropriate amount.
 238          * I'm not sure what is appropriate.
 239          */
 240         ttyflush(tp, FREAD | FWRITE);
 241         clist_alloc_cblocks(&tp->t_canq, 0);
 242         clist_alloc_cblocks(&tp->t_rawq, 0);
 243         clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER);
 244
 245 done:
 246         /* Done */
 247         lwkt_reltoken(&tp->t_token);
 248         return (error);
 249 }
 250
 251 /*
 252  * Line specific close routine, called from device close routine
 253  * and from ttioctl at >= splsofttty(). This causes the node to
 254  * be destroyed as well.
 255  */
 256 static int
 257 ngt_close(struct tty *tp, int flag)
 258 {
 259         const sc_p sc = (sc_p) tp->t_sc;
 260
 261         lwkt_gettoken(&tp->t_token);
 262         ttyflush(tp, FREAD | FWRITE);
 263         clist_free_cblocks(&tp->t_outq);
 264         tp->t_line = 0;
 265         if (sc != NULL) {
 266                 if (sc->flags & FLG_TIMEOUT) {
 267                         callout_stop(&sc->ctimeout);
 268                         sc->flags &= ~FLG_TIMEOUT;
 269                 }
 270                 ngt_nodeop_ok = 1;
 271                 ng_rmnode(sc->node);
 272                 ngt_nodeop_ok = 0;
 273                 tp->t_sc = NULL;
 274         }
 275         lwkt_reltoken(&tp->t_token);
 276
 277         return (0);
 278 }
 279
 280 /*
 281  * Once the device has been turned into a node, we don't allow reading.
 282  */
 283 static int
 284 ngt_read(struct tty *tp, struct uio *uio, int flag)
 285 {
 286         return (EIO);
 287 }
 288
 289 /*
 290  * Once the device has been turned into a node, we don't allow writing.
 291  */
 292 static int
 293 ngt_write(struct tty *tp, struct uio *uio, int flag)
 294 {
 295         return (EIO);
 296 }
 297
 298 /*
 299  * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
 300  */
 301 static int
 302 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred)
 303 {
 304         const sc_p sc = (sc_p) tp->t_sc;
 305         int error = 0;
 306
 307         lwkt_gettoken(&tp->t_token);
 308
 309         switch (cmd) {
 310         case NGIOCGINFO:
 311             {
 312                 struct nodeinfo *const ni = (struct nodeinfo *) data;
 313                 const node_p node = sc->node;
 314
 315                 bzero(ni, sizeof(*ni));
 316                 if (node->name)
 317                         strncpy(ni->name, node->name, sizeof(ni->name) - 1);
 318                 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
 319                 ni->id = (u_int32_t)(uintptr_t)node;
 320                 ni->hooks = node->numhooks;
 321                 break;
 322             }
 323         default:
 324                 ERROUT(ENOIOCTL);
 325         }
 326 done:
 327         lwkt_reltoken(&tp->t_token);
 328
 329         return (error);
 330 }
 331
 332 /*
 333  * Receive data coming from the device. We get one character at
 334  * a time, which is kindof silly.
 335  * Only guaranteed to be at splsofttty() or spltty().
 336  */
 337 static int
 338 ngt_input(int c, struct tty *tp)
 339 {
 340         const sc_p sc = (sc_p) tp->t_sc;
 341         const node_p node = sc ? sc->node : NULL;
 342         struct mbuf *m;
 343         int error = 0;
 344
 345         lwkt_gettoken(&tp->t_token);
 346         if (!sc || tp != sc->tp) {
 347                 lwkt_reltoken(&tp->t_token);
 348                 return (0);
 349         }
 350         if (!sc->hook)
 351                 ERROUT(0);
 352
 353         /* Check for error conditions */
 354         if ((tp->t_state & TS_CONNECTED) == 0) {
 355                 if (sc->flags & FLG_DEBUG)
 356                         log(LOG_DEBUG, "%s: no carrier\n", node->name);
 357                 ERROUT(0);
 358         }
 359         if (c & TTY_ERRORMASK) {
 360                 /* framing error or overrun on this char */
 361                 if (sc->flags & FLG_DEBUG)
 362                         log(LOG_DEBUG, "%s: line error %x\n",
 363                             node->name, c & TTY_ERRORMASK);
 364                 ERROUT(0);
 365         }
 366         c &= TTY_CHARMASK;
 367
 368         /* Get a new header mbuf if we need one */
 369         if (!(m = sc->m)) {
 370                 MGETHDR(m, M_NOWAIT, MT_DATA);
 371                 if (!m) {
 372                         if (sc->flags & FLG_DEBUG)
 373                                 log(LOG_ERR,
 374                                     "%s: can't get mbuf\n", node->name);
 375                         ERROUT(ENOBUFS);
 376                 }
 377                 m->m_len = m->m_pkthdr.len = 0;
 378                 m->m_pkthdr.rcvif = NULL;
 379                 sc->m = m;
 380         }
 381
 382         /* Add char to mbuf */
 383         *mtod(m, u_char *) = c;
 384         m->m_data++;
 385         m->m_len++;
 386         m->m_pkthdr.len++;
 387
 388         /* Ship off mbuf if it's time */
 389         if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
 390                 m->m_data = m->m_pktdat;
 391                 error = ng_queue_data(sc->hook, m, NULL);
 392                 sc->m = NULL;
 393         }
 394 done:
 395         lwkt_reltoken(&tp->t_token);
 396
 397         return (error);
 398 }
 399
 400 /*
 401  * This is called when the device driver is ready for more output.
 402  * Called from tty system at splsofttty() or spltty().
 403  * Also call from ngt_rcv_data() when a new mbuf is available for output.
 404  */
 405 static int
 406 ngt_start(struct tty *tp)
 407 {
 408         const sc_p sc = (sc_p) tp->t_sc;
 409
 410         lwkt_gettoken(&tp->t_token);
 411         while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
 412                 struct mbuf *m = sc->qhead;
 413
 414                 /* Remove first mbuf from queue */
 415                 if (!m)
 416                         break;
 417                 if ((sc->qhead = m->m_nextpkt) == NULL)
 418                         sc->qtail = &sc->qhead;
 419                 sc->qlen--;
 420                 QUEUECHECK(sc);
 421
 422                 /* Send as much of it as possible */
 423                 while (m) {
 424                         int     sent;
 425
 426                         sent = m->m_len - clist_btoq(mtod(m, u_char *),
 427                                                      m->m_len, &tp->t_outq);
 428                         m->m_data += sent;
 429                         m->m_len -= sent;
 430                         if (m->m_len > 0)
 431                                 break;  /* device can't take no more */
 432                         m = m_free(m);
 433                 }
 434
 435                 /* Put remainder of mbuf chain (if any) back on queue */
 436                 if (m) {
 437                         m->m_nextpkt = sc->qhead;
 438                         sc->qhead = m;
 439                         if (sc->qtail == &sc->qhead)
 440                                 sc->qtail = &m->m_nextpkt;
 441                         sc->qlen++;
 442                         QUEUECHECK(sc);
 443                         break;
 444                 }
 445         }
 446
 447         /* Call output process whether or not there is any output. We are
 448          * being called in lieu of ttstart and must do what it would. */
 449         if (tp->t_oproc != NULL)
 450                 (*tp->t_oproc) (tp);
 451
 452         /* This timeout is needed for operation on a pseudo-tty, because the
 453          * pty code doesn't call pppstart after it has drained the t_outq. */
 454         if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
 455                 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc);
 456                 sc->flags |= FLG_TIMEOUT;
 457         }
 458         lwkt_reltoken(&tp->t_token);
 459
 460         return (0);
 461 }
 462
 463 /*
 464  * We still have data to output to the device, so try sending more.
 465  */
 466 static void
 467 ngt_timeout(void *arg)
 468 {
 469         const sc_p sc = (sc_p) arg;
 470         struct tty *tp = sc->tp;
 471
 472         lwkt_gettoken(&tp->t_token);
 473         sc->flags &= ~FLG_TIMEOUT;
 474         ngt_start(tp);
 475         lwkt_reltoken(&tp->t_token);
 476 }
 477
 478 /******************************************************************
 479                     NETGRAPH NODE METHODS
 480 ******************************************************************/
 481
 482 /*
 483  * Initialize a new node of this type.
 484  *
 485  * We only allow nodes to be created as a result of setting
 486  * the line discipline on a tty, so always return an error if not.
 487  */
 488 static int
 489 ngt_constructor(node_p *nodep)
 490 {
 491         if (!ngt_nodeop_ok)
 492                 return (EOPNOTSUPP);
 493         return (ng_make_node_common(&typestruct, nodep));
 494 }
 495
 496 /*
 497  * Add a new hook. There can only be one.
 498  */
 499 static int
 500 ngt_newhook(node_p node, hook_p hook, const char *name)
 501 {
 502         const sc_p sc = node->private;
 503         struct tty *tp = sc->tp;
 504         int error = 0;
 505
 506         if (strcmp(name, NG_TTY_HOOK))
 507                 return (EINVAL);
 508         lwkt_gettoken(&tp->t_token);
 509         if (sc->hook)
 510                 ERROUT(EISCONN);
 511         sc->hook = hook;
 512 done:
 513         lwkt_reltoken(&tp->t_token);
 514
 515         return (error);
 516 }
 517
 518 /*
 519  * Disconnect the hook
 520  */
 521 static int
 522 ngt_disconnect(hook_p hook)
 523 {
 524         const sc_p sc = hook->node->private;
 525         struct tty *tp = sc->tp;
 526
 527         lwkt_gettoken(&tp->t_token);
 528         if (hook != sc->hook)
 529                 panic(__func__);
 530         sc->hook = NULL;
 531         m_freem(sc->m);
 532         sc->m = NULL;
 533         lwkt_reltoken(&tp->t_token);
 534
 535         return (0);
 536 }
 537
 538 /*
 539  * Remove this node. The does the netgraph portion of the shutdown.
 540  * This should only be called indirectly from ngt_close().
 541  */
 542 static int
 543 ngt_shutdown(node_p node)
 544 {
 545         const sc_p sc = node->private;
 546         struct tty *tp = sc->tp;
 547
 548         if (!ngt_nodeop_ok)
 549                 return (EOPNOTSUPP);
 550         lwkt_gettoken(&tp->t_token);
 551         ng_unname(node);
 552         ng_cutlinks(node);
 553         node->private = NULL;
 554         ng_unref(sc->node);
 555         m_freem(sc->qhead);
 556         m_freem(sc->m);
 557         bzero(sc, sizeof(*sc));
 558         kfree(sc, M_NETGRAPH);
 559         lwkt_reltoken(&tp->t_token);
 560
 561         return (0);
 562 }
 563
 564 /*
 565  * Receive incoming data from netgraph system. Put it on our
 566  * output queue and start output if necessary.
 567  */
 568 static int
 569 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 570 {
 571         const sc_p sc = hook->node->private;
 572         struct tty *tp = sc->tp;
 573         int error = 0;
 574
 575         if (hook != sc->hook)
 576                 panic(__func__);
 577         NG_FREE_META(meta);
 578         lwkt_gettoken(&tp->t_token);
 579         if (sc->qlen >= MAX_MBUFQ)
 580                 ERROUT(ENOBUFS);
 581         m->m_nextpkt = NULL;
 582         *sc->qtail = m;
 583         sc->qtail = &m->m_nextpkt;
 584         sc->qlen++;
 585         QUEUECHECK(sc);
 586         m = NULL;
 587         if (sc->qlen == 1)
 588                 ngt_start(sc->tp);
 589 done:
 590         lwkt_reltoken(&tp->t_token);
 591         if (m)
 592                 m_freem(m);
 593         return (error);
 594 }
 595
 596 /*
 597  * Receive control message
 598  */
 599 static int
 600 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
 601            struct ng_mesg **rptr)
 602 {
 603         const sc_p sc = (sc_p) node->private;
 604         struct tty *tp = sc->tp;
 605         struct ng_mesg *resp = NULL;
 606         int error = 0;
 607
 608         lwkt_gettoken(&tp->t_token);
 609         switch (msg->header.typecookie) {
 610         case NGM_TTY_COOKIE:
 611                 switch (msg->header.cmd) {
 612                 case NGM_TTY_SET_HOTCHAR:
 613                     {
 614                         int     hotchar;
 615
 616                         if (msg->header.arglen != sizeof(int))
 617                                 ERROUT(EINVAL);
 618                         hotchar = *((int *) msg->data);
 619                         if (hotchar != (u_char) hotchar && hotchar != -1)
 620                                 ERROUT(EINVAL);
 621                         sc->hotchar = hotchar;  /* race condition is OK */
 622                         break;
 623                     }
 624                 case NGM_TTY_GET_HOTCHAR:
 625                         NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
 626                         if (!resp)
 627                                 ERROUT(ENOMEM);
 628                         /* Race condition here is OK */
 629                         *((int *) resp->data) = sc->hotchar;
 630                         break;
 631                 default:
 632                         ERROUT(EINVAL);
 633                 }
 634                 break;
 635         default:
 636                 ERROUT(EINVAL);
 637         }
 638         if (rptr)
 639                 *rptr = resp;
 640         else if (resp)
 641                 kfree(resp, M_NETGRAPH);
 642
 643 done:
 644         kfree(msg, M_NETGRAPH);
 645         lwkt_reltoken(&tp->t_token);
 646
 647         return (error);
 648 }
 649
 650 /******************************************************************
 651                         INITIALIZATION
 652 ******************************************************************/
 653
 654 /*
 655  * Handle loading and unloading for this node type
 656  */
 657 static int
 658 ngt_mod_event(module_t mod, int event, void *data)
 659 {
 660         /* struct ng_type *const type = data;*/
 661         int error = 0;
 662
 663         switch (event) {
 664         case MOD_LOAD:
 665                 /* Register line discipline */
 666                 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
 667                         log(LOG_ERR, "%s: can't register line discipline",
 668                             __func__);
 669                         return (EIO);
 670                 }
 671                 break;
 672
 673         case MOD_UNLOAD:
 674
 675                 /* Unregister line discipline */
 676                 ldisc_deregister(ngt_ldisc);
 677                 break;
 678
 679         default:
 680                 error = EOPNOTSUPP;
 681                 break;
 682         }
 683         return (error);
 684 }