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/priv.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 #include <sys/thread2.h>
  76
  77 #include <netgraph/ng_message.h>
  78 #include <netgraph/netgraph.h>
  79 #include "ng_tty.h"
  80
  81 /* Misc defs */
  82 #define MAX_MBUFQ               3       /* Max number of queued mbufs */
  83 #define NGT_HIWATER             400     /* High water mark on output */
  84
  85 /* Per-node private info */
  86 struct ngt_sc {
  87         struct  tty *tp;                /* Terminal device */
  88         node_p  node;                   /* Netgraph node */
  89         hook_p  hook;                   /* Netgraph hook */
  90         struct  mbuf *m;                /* Incoming data buffer */
  91         struct  mbuf *qhead, **qtail;   /* Queue of outgoing mbuf's */
  92         short   qlen;                   /* Length of queue */
  93         short   hotchar;                /* Hotchar, or -1 if none */
  94         u_int   flags;                  /* Flags */
  95         struct  callout ctimeout;       /* See man timeout(9) */
  96 };
  97 typedef struct ngt_sc *sc_p;
  98
  99 /* Flags */
 100 #define FLG_TIMEOUT             0x0001  /* A timeout is pending */
 101 #define FLG_DEBUG               0x0002
 102
 103 /* Debugging */
 104 #ifdef INVARIANTS
 105 #define QUEUECHECK(sc)                                                  \
 106     do {                                                                \
 107       struct mbuf       **mp;                                           \
 108       int               k;                                              \
 109                                                                         \
 110       for (k = 0, mp = &sc->qhead;                                      \
 111         k <= MAX_MBUFQ && *mp;                                          \
 112         k++, mp = &(*mp)->m_nextpkt);                                   \
 113       if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail)     \
 114         panic("%s: queue", __func__);                           \
 115     } while (0)
 116 #else
 117 #define QUEUECHECK(sc)  do {} while (0)
 118 #endif
 119
 120 /* Line discipline methods */
 121 static int      ngt_open(cdev_t dev, struct tty *tp);
 122 static int      ngt_close(struct tty *tp, int flag);
 123 static int      ngt_read(struct tty *tp, struct uio *uio, int flag);
 124 static int      ngt_write(struct tty *tp, struct uio *uio, int flag);
 125 static int      ngt_tioctl(struct tty *tp,
 126                     u_long cmd, caddr_t data, int flag, struct ucred *cred);
 127 static int      ngt_input(int c, struct tty *tp);
 128 static int      ngt_start(struct tty *tp);
 129
 130 /* Netgraph methods */
 131 static ng_constructor_t ngt_constructor;
 132 static ng_rcvmsg_t      ngt_rcvmsg;
 133 static ng_shutdown_t    ngt_shutdown;
 134 static ng_newhook_t     ngt_newhook;
 135 static ng_rcvdata_t     ngt_rcvdata;
 136 static ng_disconnect_t  ngt_disconnect;
 137 static int      ngt_mod_event(module_t mod, int event, void *data);
 138
 139 /* Other stuff */
 140 static void     ngt_timeout(void *arg);
 141
 142 #define ERROUT(x)               do { error = (x); goto done; } while (0)
 143
 144 /* Line discipline descriptor */
 145 static struct linesw ngt_disc = {
 146         ngt_open,
 147         ngt_close,
 148         ngt_read,
 149         ngt_write,
 150         ngt_tioctl,
 151         ngt_input,
 152         ngt_start,
 153         ttymodem,
 154         NG_TTY_DFL_HOTCHAR      /* XXX can't change this in serial driver */
 155 };
 156
 157 /* Netgraph node type descriptor */
 158 static struct ng_type typestruct = {
 159         NG_VERSION,
 160         NG_TTY_NODE_TYPE,
 161         ngt_mod_event,
 162         ngt_constructor,
 163         ngt_rcvmsg,
 164         ngt_shutdown,
 165         ngt_newhook,
 166         NULL,
 167         NULL,
 168         ngt_rcvdata,
 169         ngt_rcvdata,
 170         ngt_disconnect,
 171         NULL
 172 };
 173 NETGRAPH_INIT(tty, &typestruct);
 174
 175 static int ngt_unit;
 176 static int ngt_nodeop_ok;       /* OK to create/remove node */
 177 static int ngt_ldisc;
 178
 179 /******************************************************************
 180                     LINE DISCIPLINE METHODS
 181 ******************************************************************/
 182
 183 /*
 184  * Set our line discipline on the tty.
 185  * Called from device open routine or ttioctl() at >= splsofttty()
 186  */
 187 static int
 188 ngt_open(cdev_t dev, struct tty *tp)
 189 {
 190         struct thread *td = curthread;  /* XXX */
 191         char name[sizeof(NG_TTY_NODE_TYPE) + 8];
 192         sc_p sc;
 193         int error;
 194
 195         /* Super-user only */
 196         if ((error = priv_check(td, PRIV_ROOT)))
 197                 return (error);
 198         crit_enter();
 199         lwkt_gettoken(&tty_token);
 200
 201         /* Already installed? */
 202         if (tp->t_line == NETGRAPHDISC) {
 203                 sc = (sc_p) tp->t_sc;
 204                 if (sc != NULL && sc->tp == tp)
 205                         goto done;
 206         }
 207
 208         /* Initialize private struct */
 209         sc = kmalloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
 210         sc->tp = tp;
 211         sc->hotchar = NG_TTY_DFL_HOTCHAR;
 212         sc->qtail = &sc->qhead;
 213         QUEUECHECK(sc);
 214         callout_init_mp(&sc->ctimeout);
 215
 216         /* Setup netgraph node */
 217         ngt_nodeop_ok = 1;
 218         error = ng_make_node_common(&typestruct, &sc->node);
 219         ngt_nodeop_ok = 0;
 220         if (error) {
 221                 kfree(sc, M_NETGRAPH);
 222                 goto done;
 223         }
 224         ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
 225
 226         /* Set back pointers */
 227         sc->node->private = sc;
 228         tp->t_sc = (caddr_t) sc;
 229
 230         /* Assign node its name */
 231         if ((error = ng_name_node(sc->node, name))) {
 232                 log(LOG_ERR, "%s: node name exists?\n", name);
 233                 ngt_nodeop_ok = 1;
 234                 ng_rmnode(sc->node);
 235                 ngt_nodeop_ok = 0;
 236                 goto done;
 237         }
 238
 239         /*
 240          * Pre-allocate cblocks to the an appropriate amount.
 241          * I'm not sure what is appropriate.
 242          */
 243         ttyflush(tp, FREAD | FWRITE);
 244         clist_alloc_cblocks(&tp->t_canq, 0, 0);
 245         clist_alloc_cblocks(&tp->t_rawq, 0, 0);
 246         clist_alloc_cblocks(&tp->t_outq,
 247             MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
 248
 249 done:
 250         /* Done */
 251         lwkt_reltoken(&tty_token);
 252         crit_exit();
 253         return (error);
 254 }
 255
 256 /*
 257  * Line specific close routine, called from device close routine
 258  * and from ttioctl at >= splsofttty(). This causes the node to
 259  * be destroyed as well.
 260  */
 261 static int
 262 ngt_close(struct tty *tp, int flag)
 263 {
 264         const sc_p sc = (sc_p) tp->t_sc;
 265
 266         crit_enter();
 267         lwkt_gettoken(&tty_token);
 268         ttyflush(tp, FREAD | FWRITE);
 269         clist_free_cblocks(&tp->t_outq);
 270         tp->t_line = 0;
 271         if (sc != NULL) {
 272                 if (sc->flags & FLG_TIMEOUT) {
 273                         callout_stop(&sc->ctimeout);
 274                         sc->flags &= ~FLG_TIMEOUT;
 275                 }
 276                 ngt_nodeop_ok = 1;
 277                 ng_rmnode(sc->node);
 278                 ngt_nodeop_ok = 0;
 279                 tp->t_sc = NULL;
 280         }
 281         lwkt_reltoken(&tty_token);
 282         crit_exit();
 283         return (0);
 284 }
 285
 286 /*
 287  * Once the device has been turned into a node, we don't allow reading.
 288  */
 289 static int
 290 ngt_read(struct tty *tp, struct uio *uio, int flag)
 291 {
 292         return (EIO);
 293 }
 294
 295 /*
 296  * Once the device has been turned into a node, we don't allow writing.
 297  */
 298 static int
 299 ngt_write(struct tty *tp, struct uio *uio, int flag)
 300 {
 301         return (EIO);
 302 }
 303
 304 /*
 305  * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
 306  */
 307 static int
 308 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred)
 309 {
 310         const sc_p sc = (sc_p) tp->t_sc;
 311         int error = 0;
 312
 313         crit_enter();
 314         lwkt_gettoken(&tty_token);
 315         switch (cmd) {
 316         case NGIOCGINFO:
 317             {
 318                 struct nodeinfo *const ni = (struct nodeinfo *) data;
 319                 const node_p node = sc->node;
 320
 321                 bzero(ni, sizeof(*ni));
 322                 if (node->name)
 323                         strncpy(ni->name, node->name, sizeof(ni->name) - 1);
 324                 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
 325                 ni->id = (u_int32_t)(uintptr_t)node;
 326                 ni->hooks = node->numhooks;
 327                 break;
 328             }
 329         default:
 330                 ERROUT(ENOIOCTL);
 331         }
 332 done:
 333         lwkt_reltoken(&tty_token);
 334         crit_exit();
 335         return (error);
 336 }
 337
 338 /*
 339  * Receive data coming from the device. We get one character at
 340  * a time, which is kindof silly.
 341  * Only guaranteed to be at splsofttty() or spltty().
 342  */
 343 static int
 344 ngt_input(int c, struct tty *tp)
 345 {
 346         const sc_p sc = (sc_p) tp->t_sc;
 347         const node_p node = sc ? sc->node : NULL;
 348         struct mbuf *m;
 349         int error = 0;
 350
 351         lwkt_gettoken(&tty_token);
 352         if (!sc || tp != sc->tp) {
 353                 lwkt_reltoken(&tty_token);
 354                 return (0);
 355         }
 356         crit_enter();
 357         if (!sc->hook)
 358                 ERROUT(0);
 359
 360         /* Check for error conditions */
 361         if ((tp->t_state & TS_CONNECTED) == 0) {
 362                 if (sc->flags & FLG_DEBUG)
 363                         log(LOG_DEBUG, "%s: no carrier\n", node->name);
 364                 ERROUT(0);
 365         }
 366         if (c & TTY_ERRORMASK) {
 367                 /* framing error or overrun on this char */
 368                 if (sc->flags & FLG_DEBUG)
 369                         log(LOG_DEBUG, "%s: line error %x\n",
 370                             node->name, c & TTY_ERRORMASK);
 371                 ERROUT(0);
 372         }
 373         c &= TTY_CHARMASK;
 374
 375         /* Get a new header mbuf if we need one */
 376         if (!(m = sc->m)) {
 377                 MGETHDR(m, MB_DONTWAIT, MT_DATA);
 378                 if (!m) {
 379                         if (sc->flags & FLG_DEBUG)
 380                                 log(LOG_ERR,
 381                                     "%s: can't get mbuf\n", node->name);
 382                         ERROUT(ENOBUFS);
 383                 }
 384                 m->m_len = m->m_pkthdr.len = 0;
 385                 m->m_pkthdr.rcvif = NULL;
 386                 sc->m = m;
 387         }
 388
 389         /* Add char to mbuf */
 390         *mtod(m, u_char *) = c;
 391         m->m_data++;
 392         m->m_len++;
 393         m->m_pkthdr.len++;
 394
 395         /* Ship off mbuf if it's time */
 396         if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
 397                 m->m_data = m->m_pktdat;
 398                 error = ng_queue_data(sc->hook, m, NULL);
 399                 sc->m = NULL;
 400         }
 401 done:
 402         crit_exit();
 403         lwkt_reltoken(&tty_token);
 404         return (error);
 405 }
 406
 407 /*
 408  * This is called when the device driver is ready for more output.
 409  * Called from tty system at splsofttty() or spltty().
 410  * Also call from ngt_rcv_data() when a new mbuf is available for output.
 411  */
 412 static int
 413 ngt_start(struct tty *tp)
 414 {
 415         const sc_p sc = (sc_p) tp->t_sc;
 416
 417         crit_enter();
 418         lwkt_gettoken(&tty_token);
 419         while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
 420                 struct mbuf *m = sc->qhead;
 421
 422                 /* Remove first mbuf from queue */
 423                 if (!m)
 424                         break;
 425                 if ((sc->qhead = m->m_nextpkt) == NULL)
 426                         sc->qtail = &sc->qhead;
 427                 sc->qlen--;
 428                 QUEUECHECK(sc);
 429
 430                 /* Send as much of it as possible */
 431                 while (m) {
 432                         int     sent;
 433
 434                         sent = m->m_len
 435                             - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
 436                         m->m_data += sent;
 437                         m->m_len -= sent;
 438                         if (m->m_len > 0)
 439                                 break;  /* device can't take no more */
 440                         m = m_free(m);
 441                 }
 442
 443                 /* Put remainder of mbuf chain (if any) back on queue */
 444                 if (m) {
 445                         m->m_nextpkt = sc->qhead;
 446                         sc->qhead = m;
 447                         if (sc->qtail == &sc->qhead)
 448                                 sc->qtail = &m->m_nextpkt;
 449                         sc->qlen++;
 450                         QUEUECHECK(sc);
 451                         break;
 452                 }
 453         }
 454
 455         /* Call output process whether or not there is any output. We are
 456          * being called in lieu of ttstart and must do what it would. */
 457         if (tp->t_oproc != NULL)
 458                 (*tp->t_oproc) (tp);
 459
 460         /* This timeout is needed for operation on a pseudo-tty, because the
 461          * pty code doesn't call pppstart after it has drained the t_outq. */
 462         if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
 463                 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc);
 464                 sc->flags |= FLG_TIMEOUT;
 465         }
 466         lwkt_reltoken(&tty_token);
 467         crit_exit();
 468         return (0);
 469 }
 470
 471 /*
 472  * We still have data to output to the device, so try sending more.
 473  */
 474 static void
 475 ngt_timeout(void *arg)
 476 {
 477         const sc_p sc = (sc_p) arg;
 478
 479         crit_enter();
 480         lwkt_gettoken(&tty_token);
 481         sc->flags &= ~FLG_TIMEOUT;
 482         ngt_start(sc->tp);
 483         lwkt_reltoken(&tty_token);
 484         crit_exit();
 485 }
 486
 487 /******************************************************************
 488                     NETGRAPH NODE METHODS
 489 ******************************************************************/
 490
 491 /*
 492  * Initialize a new node of this type.
 493  *
 494  * We only allow nodes to be created as a result of setting
 495  * the line discipline on a tty, so always return an error if not.
 496  */
 497 static int
 498 ngt_constructor(node_p *nodep)
 499 {
 500         if (!ngt_nodeop_ok)
 501                 return (EOPNOTSUPP);
 502         return (ng_make_node_common(&typestruct, nodep));
 503 }
 504
 505 /*
 506  * Add a new hook. There can only be one.
 507  */
 508 static int
 509 ngt_newhook(node_p node, hook_p hook, const char *name)
 510 {
 511         const sc_p sc = node->private;
 512         int error = 0;
 513
 514         if (strcmp(name, NG_TTY_HOOK))
 515                 return (EINVAL);
 516         crit_enter();
 517         lwkt_gettoken(&tty_token);
 518         if (sc->hook)
 519                 ERROUT(EISCONN);
 520         sc->hook = hook;
 521 done:
 522         lwkt_reltoken(&tty_token);
 523         crit_exit();
 524         return (error);
 525 }
 526
 527 /*
 528  * Disconnect the hook
 529  */
 530 static int
 531 ngt_disconnect(hook_p hook)
 532 {
 533         const sc_p sc = hook->node->private;
 534
 535         crit_enter();
 536         lwkt_gettoken(&tty_token);
 537         if (hook != sc->hook)
 538                 panic(__func__);
 539         sc->hook = NULL;
 540         m_freem(sc->m);
 541         sc->m = NULL;
 542         lwkt_reltoken(&tty_token);
 543         crit_exit();
 544         return (0);
 545 }
 546
 547 /*
 548  * Remove this node. The does the netgraph portion of the shutdown.
 549  * This should only be called indirectly from ngt_close().
 550  */
 551 static int
 552 ngt_shutdown(node_p node)
 553 {
 554         const sc_p sc = node->private;
 555
 556         if (!ngt_nodeop_ok)
 557                 return (EOPNOTSUPP);
 558         lwkt_gettoken(&tty_token);
 559         ng_unname(node);
 560         ng_cutlinks(node);
 561         node->private = NULL;
 562         ng_unref(sc->node);
 563         m_freem(sc->qhead);
 564         m_freem(sc->m);
 565         bzero(sc, sizeof(*sc));
 566         kfree(sc, M_NETGRAPH);
 567         lwkt_reltoken(&tty_token);
 568         return (0);
 569 }
 570
 571 /*
 572  * Receive incoming data from netgraph system. Put it on our
 573  * output queue and start output if necessary.
 574  */
 575 static int
 576 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 577 {
 578         const sc_p sc = hook->node->private;
 579         int error = 0;
 580
 581         if (hook != sc->hook)
 582                 panic(__func__);
 583         NG_FREE_META(meta);
 584         crit_enter();
 585         lwkt_gettoken(&tty_token);
 586         if (sc->qlen >= MAX_MBUFQ)
 587                 ERROUT(ENOBUFS);
 588         m->m_nextpkt = NULL;
 589         *sc->qtail = m;
 590         sc->qtail = &m->m_nextpkt;
 591         sc->qlen++;
 592         QUEUECHECK(sc);
 593         m = NULL;
 594         if (sc->qlen == 1)
 595                 ngt_start(sc->tp);
 596 done:
 597         lwkt_reltoken(&tty_token);
 598         crit_exit();
 599         if (m)
 600                 m_freem(m);
 601         return (error);
 602 }
 603
 604 /*
 605  * Receive control message
 606  */
 607 static int
 608 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
 609            struct ng_mesg **rptr)
 610 {
 611         const sc_p sc = (sc_p) node->private;
 612         struct ng_mesg *resp = NULL;
 613         int error = 0;
 614
 615         lwkt_gettoken(&tty_token);
 616         switch (msg->header.typecookie) {
 617         case NGM_TTY_COOKIE:
 618                 switch (msg->header.cmd) {
 619                 case NGM_TTY_SET_HOTCHAR:
 620                     {
 621                         int     hotchar;
 622
 623                         if (msg->header.arglen != sizeof(int))
 624                                 ERROUT(EINVAL);
 625                         hotchar = *((int *) msg->data);
 626                         if (hotchar != (u_char) hotchar && hotchar != -1)
 627                                 ERROUT(EINVAL);
 628                         sc->hotchar = hotchar;  /* race condition is OK */
 629                         break;
 630                     }
 631                 case NGM_TTY_GET_HOTCHAR:
 632                         NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
 633                         if (!resp)
 634                                 ERROUT(ENOMEM);
 635                         /* Race condition here is OK */
 636                         *((int *) resp->data) = sc->hotchar;
 637                         break;
 638                 default:
 639                         ERROUT(EINVAL);
 640                 }
 641                 break;
 642         default:
 643                 ERROUT(EINVAL);
 644         }
 645         if (rptr)
 646                 *rptr = resp;
 647         else if (resp)
 648                 kfree(resp, M_NETGRAPH);
 649
 650 done:
 651         kfree(msg, M_NETGRAPH);
 652         lwkt_reltoken(&tty_token);
 653         return (error);
 654 }
 655
 656 /******************************************************************
 657                         INITIALIZATION
 658 ******************************************************************/
 659
 660 /*
 661  * Handle loading and unloading for this node type
 662  */
 663 static int
 664 ngt_mod_event(module_t mod, int event, void *data)
 665 {
 666         /* struct ng_type *const type = data;*/
 667         int error = 0;
 668
 669         lwkt_gettoken(&tty_token);
 670         switch (event) {
 671         case MOD_LOAD:
 672                 /* Register line discipline */
 673                 crit_enter();
 674                 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
 675                         crit_exit();
 676                         log(LOG_ERR, "%s: can't register line discipline",
 677                             __func__);
 678                         return (EIO);
 679                 }
 680                 crit_exit();
 681                 break;
 682
 683         case MOD_UNLOAD:
 684
 685                 /* Unregister line discipline */
 686                 crit_enter();
 687                 ldisc_deregister(ngt_ldisc);
 688                 crit_exit();
 689                 break;
 690
 691         default:
 692                 error = EOPNOTSUPP;
 693                 break;
 694         }
 695         lwkt_reltoken(&tty_token);
 696         return (error);
 697 }