sys/netgraph/ng_tty.c

   1 /*
   2  * ng_tty.c
   3  */
   4
   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  * Updated by Andrew Thompson <thompsa@FreeBSD.org> for MPSAFE TTY.
  41  * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
  42  */
  43
  44 /*
  45  * This file implements TTY hooks to link in to the netgraph system.  The node
  46  * is created and then passed the callers opened TTY file descriptor number to
  47  * NGM_TTY_SET_TTY, this will hook the tty via ttyhook_register().
  48  *
  49  * Incoming data is delivered directly to ng_tty via the TTY bypass hook as a
  50  * buffer pointer and length, this is converted to a mbuf and passed to the
  51  * peer.
  52  *
  53  * If the TTY device does not support bypass then incoming characters are
  54  * delivered to the hook one at a time, each in its own mbuf. You may
  55  * optionally define a ``hotchar,'' which causes incoming characters to be
  56  * buffered up until either the hotchar is seen or the mbuf is full (MHLEN
  57  * bytes). Then all buffered characters are immediately delivered.
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/conf.h>
  63 #include <sys/errno.h>
  64 #include <sys/fcntl.h>
  65 #include <sys/ioccom.h>
  66 #include <sys/kernel.h>
  67 #include <sys/malloc.h>
  68 #include <sys/mbuf.h>
  69 #include <sys/priv.h>
  70 #include <sys/socket.h>
  71 #include <sys/syslog.h>
  72 #include <sys/tty.h>
  73 #include <sys/ttycom.h>
  74 #include <sys/proc.h>
  75
  76 #include <net/if.h>
  77 #include <net/if_var.h>
  78
  79 #include <netgraph/ng_message.h>
  80 #include <netgraph/netgraph.h>
  81 #include <netgraph/ng_tty.h>
  82
  83 /* Per-node private info */
  84 struct ngt_softc {
  85         struct tty      *tp;            /* Terminal device */
  86         node_p          node;           /* Netgraph node */
  87         hook_p          hook;           /* Netgraph hook */
  88         struct ifqueue  outq;           /* Queue of outgoing data */
  89         size_t          outqlen;        /* Number of bytes in outq */
  90         struct mbuf     *m;             /* Incoming non-bypass data buffer */
  91         short           hotchar;        /* Hotchar, or -1 if none */
  92         u_int           flags;          /* Flags */
  93 };
  94 typedef struct ngt_softc *sc_p;
  95
  96 /* Flags */
  97 #define FLG_DEBUG               0x0002
  98
  99 /* Netgraph methods */
 100 static ng_constructor_t         ngt_constructor;
 101 static ng_rcvmsg_t              ngt_rcvmsg;
 102 static ng_shutdown_t            ngt_shutdown;
 103 static ng_newhook_t             ngt_newhook;
 104 static ng_connect_t             ngt_connect;
 105 static ng_rcvdata_t             ngt_rcvdata;
 106 static ng_disconnect_t          ngt_disconnect;
 107
 108 #define ERROUT(x)               do { error = (x); goto done; } while (0)
 109
 110 static th_getc_inject_t         ngt_getc_inject;
 111 static th_getc_poll_t           ngt_getc_poll;
 112 static th_rint_t                ngt_rint;
 113 static th_rint_bypass_t         ngt_rint_bypass;
 114 static th_rint_poll_t           ngt_rint_poll;
 115
 116 static struct ttyhook ngt_hook = {
 117         .th_getc_inject = ngt_getc_inject,
 118         .th_getc_poll = ngt_getc_poll,
 119         .th_rint = ngt_rint,
 120         .th_rint_bypass = ngt_rint_bypass,
 121         .th_rint_poll = ngt_rint_poll,
 122 };
 123
 124 /* Netgraph node type descriptor */
 125 static struct ng_type typestruct = {
 126         .version =      NG_ABI_VERSION,
 127         .name =         NG_TTY_NODE_TYPE,
 128         .constructor =  ngt_constructor,
 129         .rcvmsg =       ngt_rcvmsg,
 130         .shutdown =     ngt_shutdown,
 131         .newhook =      ngt_newhook,
 132         .connect =      ngt_connect,
 133         .rcvdata =      ngt_rcvdata,
 134         .disconnect =   ngt_disconnect,
 135 };
 136 NETGRAPH_INIT(tty, &typestruct);
 137
 138 #define NGTLOCK(sc)     IF_LOCK(&sc->outq)
 139 #define NGTUNLOCK(sc)   IF_UNLOCK(&sc->outq)
 140
 141 /******************************************************************
 142                     NETGRAPH NODE METHODS
 143 ******************************************************************/
 144
 145 /*
 146  * Initialize a new node of this type.
 147  *
 148  * We only allow nodes to be created as a result of setting
 149  * the line discipline on a tty, so always return an error if not.
 150  */
 151 static int
 152 ngt_constructor(node_p node)
 153 {
 154         sc_p sc;
 155
 156         /* Allocate private structure */
 157         sc = malloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
 158
 159         NG_NODE_SET_PRIVATE(node, sc);
 160         sc->node = node;
 161
 162         mtx_init(&sc->outq.ifq_mtx, "ng_tty node+queue", NULL, MTX_DEF);
 163         IFQ_SET_MAXLEN(&sc->outq, ifqmaxlen);
 164
 165         return (0);
 166 }
 167
 168 /*
 169  * Add a new hook. There can only be one.
 170  */
 171 static int
 172 ngt_newhook(node_p node, hook_p hook, const char *name)
 173 {
 174         const sc_p sc = NG_NODE_PRIVATE(node);
 175
 176         if (strcmp(name, NG_TTY_HOOK))
 177                 return (EINVAL);
 178
 179         if (sc->hook)
 180                 return (EISCONN);
 181
 182         NGTLOCK(sc);
 183         sc->hook = hook;
 184         NGTUNLOCK(sc);
 185
 186         return (0);
 187 }
 188
 189 /*
 190  * Set the hook into queueing mode (for outgoing packets),
 191  * so that we wont deliver mbuf through the whole graph holding
 192  * tty locks.
 193  */
 194 static int
 195 ngt_connect(hook_p hook)
 196 {
 197         NG_HOOK_FORCE_QUEUE(hook);
 198         return (0);
 199 }
 200
 201 /*
 202  * Disconnect the hook
 203  */
 204 static int
 205 ngt_disconnect(hook_p hook)
 206 {
 207         const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 208
 209         if (hook != sc->hook)
 210                 panic("%s", __func__);
 211
 212         NGTLOCK(sc);
 213         sc->hook = NULL;
 214         NGTUNLOCK(sc);
 215
 216         return (0);
 217 }
 218
 219 /*
 220  * Remove this node. The does the netgraph portion of the shutdown.
 221  */
 222 static int
 223 ngt_shutdown(node_p node)
 224 {
 225         const sc_p sc = NG_NODE_PRIVATE(node);
 226         struct tty *tp;
 227
 228         tp = sc->tp;
 229         if (tp != NULL) {
 230                 tty_lock(tp);
 231                 ttyhook_unregister(tp);
 232         }
 233         /* Free resources */
 234         IF_DRAIN(&sc->outq);
 235         mtx_destroy(&(sc)->outq.ifq_mtx);
 236         NG_NODE_UNREF(sc->node);
 237         free(sc, M_NETGRAPH);
 238
 239         return (0);
 240 }
 241
 242 /*
 243  * Receive control message
 244  */
 245 static int
 246 ngt_rcvmsg(node_p node, item_p item, hook_p lasthook)
 247 {
 248         struct proc *p;
 249         const sc_p sc = NG_NODE_PRIVATE(node);
 250         struct ng_mesg *msg, *resp = NULL;
 251         int error = 0;
 252
 253         NGI_GET_MSG(item, msg);
 254         switch (msg->header.typecookie) {
 255         case NGM_TTY_COOKIE:
 256                 switch (msg->header.cmd) {
 257                 case NGM_TTY_SET_TTY:
 258                         if (sc->tp != NULL)
 259                                 return (EBUSY);
 260
 261                         p = pfind(((int *)msg->data)[0]);
 262                         if (p == NULL || (p->p_flag & P_WEXIT))
 263                                 return (ESRCH);
 264                         _PHOLD(p);
 265                         PROC_UNLOCK(p);
 266                         error = ttyhook_register(&sc->tp, p, ((int *)msg->data)[1],
 267                             &ngt_hook, sc);
 268                         PRELE(p);
 269                         if (error != 0)
 270                                 return (error);
 271                         break;
 272                 case NGM_TTY_SET_HOTCHAR:
 273                     {
 274                         int     hotchar;
 275
 276                         if (msg->header.arglen != sizeof(int))
 277                                 ERROUT(EINVAL);
 278                         hotchar = *((int *) msg->data);
 279                         if (hotchar != (u_char) hotchar && hotchar != -1)
 280                                 ERROUT(EINVAL);
 281                         sc->hotchar = hotchar;  /* race condition is OK */
 282                         break;
 283                     }
 284                 case NGM_TTY_GET_HOTCHAR:
 285                         NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
 286                         if (!resp)
 287                                 ERROUT(ENOMEM);
 288                         /* Race condition here is OK */
 289                         *((int *) resp->data) = sc->hotchar;
 290                         break;
 291                 default:
 292                         ERROUT(EINVAL);
 293                 }
 294                 break;
 295         default:
 296                 ERROUT(EINVAL);
 297         }
 298 done:
 299         NG_RESPOND_MSG(error, node, item, resp);
 300         NG_FREE_MSG(msg);
 301         return (error);
 302 }
 303
 304 /*
 305  * Receive incoming data from netgraph system. Put it on our
 306  * output queue and start output if necessary.
 307  */
 308 static int
 309 ngt_rcvdata(hook_p hook, item_p item)
 310 {
 311         const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 312         struct tty *tp = sc->tp;
 313         struct mbuf *m;
 314
 315         if (hook != sc->hook)
 316                 panic("%s", __func__);
 317
 318         NGI_GET_M(item, m);
 319         NG_FREE_ITEM(item);
 320
 321         if (tp == NULL) {
 322                 NG_FREE_M(m);
 323                 return (ENXIO);
 324         }
 325
 326         IF_LOCK(&sc->outq);
 327         if (_IF_QFULL(&sc->outq)) {
 328                 IF_UNLOCK(&sc->outq);
 329                 NG_FREE_M(m);
 330                 return (ENOBUFS);
 331         }
 332
 333         _IF_ENQUEUE(&sc->outq, m);
 334         sc->outqlen += m->m_pkthdr.len;
 335         IF_UNLOCK(&sc->outq);
 336
 337         /* notify the TTY that data is ready */
 338         tty_lock(tp);
 339         if (!tty_gone(tp))
 340                 ttydevsw_outwakeup(tp);
 341         tty_unlock(tp);
 342
 343         return (0);
 344 }
 345
 346 static size_t
 347 ngt_getc_inject(struct tty *tp, void *buf, size_t len)
 348 {
 349         sc_p sc = ttyhook_softc(tp);
 350         size_t total = 0;
 351         int length;
 352
 353         while (len) {
 354                 struct mbuf *m;
 355
 356                 /* Remove first mbuf from queue */
 357                 IF_DEQUEUE(&sc->outq, m);
 358                 if (m == NULL)
 359                         break;
 360
 361                 /* Send as much of it as possible */
 362                 while (m != NULL) {
 363                         length = min(m->m_len, len);
 364                         memcpy((char *)buf + total, mtod(m, char *), length);
 365
 366                         m->m_data += length;
 367                         m->m_len -= length;
 368                         total += length;
 369                         len -= length;
 370
 371                         if (m->m_len > 0)
 372                                 break;  /* device can't take any more */
 373                         m = m_free(m);
 374                 }
 375
 376                 /* Put remainder of mbuf chain (if any) back on queue */
 377                 if (m != NULL) {
 378                         IF_PREPEND(&sc->outq, m);
 379                         break;
 380                 }
 381         }
 382         IF_LOCK(&sc->outq);
 383         sc->outqlen -= total;
 384         IF_UNLOCK(&sc->outq);
 385         MPASS(sc->outqlen >= 0);
 386
 387         return (total);
 388 }
 389
 390 static size_t
 391 ngt_getc_poll(struct tty *tp)
 392 {
 393         sc_p sc = ttyhook_softc(tp);
 394
 395         return (sc->outqlen);
 396 }
 397
 398 /*
 399  * Optimised TTY input.
 400  *
 401  * We get a buffer pointer to hopefully a complete data frame. Do not check for
 402  * the hotchar, just pass it on.
 403  */
 404 static size_t
 405 ngt_rint_bypass(struct tty *tp, const void *buf, size_t len)
 406 {
 407         sc_p sc = ttyhook_softc(tp);
 408         node_p node = sc->node;
 409         struct mbuf *m, *mb;
 410         size_t total = 0;
 411         int error = 0, length;
 412
 413         tty_assert_locked(tp);
 414
 415         if (sc->hook == NULL)
 416                 return (0);
 417
 418         m = m_getm2(NULL, len, M_NOWAIT, MT_DATA, M_PKTHDR);
 419         if (m == NULL) {
 420                 if (sc->flags & FLG_DEBUG)
 421                         log(LOG_ERR,
 422                             "%s: can't get mbuf\n", NG_NODE_NAME(node));
 423                 return (0);
 424         }
 425         m->m_pkthdr.rcvif = NULL;
 426
 427         for (mb = m; mb != NULL; mb = mb->m_next) {
 428                 length = min(M_TRAILINGSPACE(mb), len - total);
 429
 430                 memcpy(mtod(m, char *), (const char *)buf + total, length);
 431                 mb->m_len = length;
 432                 total += length;
 433                 m->m_pkthdr.len += length;
 434         }
 435         if (sc->m != NULL) {
 436                 /*
 437                  * Odd, we have changed from non-bypass to bypass. It is
 438                  * unlikely but not impossible, flush the data first.
 439                  */
 440                 NG_SEND_DATA_ONLY(error, sc->hook, sc->m);
 441                 sc->m = NULL;
 442         }
 443         NG_SEND_DATA_ONLY(error, sc->hook, m);
 444
 445         return (total);
 446 }
 447
 448 /*
 449  * Receive data coming from the device one char at a time, when it is not in
 450  * bypass mode.
 451  */
 452 static int
 453 ngt_rint(struct tty *tp, char c, int flags)
 454 {
 455         sc_p sc = ttyhook_softc(tp);
 456         node_p node = sc->node;
 457         struct mbuf *m;
 458         int error = 0;
 459
 460         tty_assert_locked(tp);
 461
 462         if (sc->hook == NULL)
 463                 return (0);
 464
 465         if (flags != 0) {
 466                 /* framing error or overrun on this char */
 467                 if (sc->flags & FLG_DEBUG)
 468                         log(LOG_DEBUG, "%s: line error %x\n",
 469                             NG_NODE_NAME(node), flags);
 470                 return (0);
 471         }
 472
 473         /* Get a new header mbuf if we need one */
 474         if (!(m = sc->m)) {
 475                 MGETHDR(m, M_NOWAIT, MT_DATA);
 476                 if (!m) {
 477                         if (sc->flags & FLG_DEBUG)
 478                                 log(LOG_ERR,
 479                                     "%s: can't get mbuf\n", NG_NODE_NAME(node));
 480                         return (ENOBUFS);
 481                 }
 482                 m->m_len = m->m_pkthdr.len = 0;
 483                 m->m_pkthdr.rcvif = NULL;
 484                 sc->m = m;
 485         }
 486
 487         /* Add char to mbuf */
 488         *mtod(m, u_char *) = c;
 489         m->m_data++;
 490         m->m_len++;
 491         m->m_pkthdr.len++;
 492
 493         /* Ship off mbuf if it's time */
 494         if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
 495                 sc->m = NULL;
 496                 NG_SEND_DATA_ONLY(error, sc->hook, m);  /* Will queue */
 497         }
 498
 499         return (error);
 500 }
 501
 502 static size_t
 503 ngt_rint_poll(struct tty *tp)
 504 {
 505         /* We can always accept input */
 506         return (1);
 507 }