sys/netgraph/ng_device.c

   1 /*
   2  * Copyright (c) 2002 Mark Santcroos <marks@ripe.net>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote products
  13  *    derived from this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * Netgraph "device" node
  27  *
  28  * This node presents a /dev/ngd%d device that interfaces to an other
  29  * netgraph node.
  30  *
  31  * $FreeBSD: src/sys/netgraph/ng_device.c,v 1.1.2.1 2002/08/23 07:15:44 julian Exp $
  32  *
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/mbuf.h>
  39 #include <sys/uio.h>
  40 #include <sys/queue.h>
  41 #include <sys/malloc.h>
  42 #include <sys/conf.h>
  43 #include <sys/poll.h>
  44
  45 #include <netgraph/ng_message.h>
  46 #include <netgraph/netgraph.h>
  47
  48 #include "ng_device.h"
  49
  50 /* turn this on for verbose messages */
  51 #define NGD_DEBUG
  52
  53 /* Netgraph methods */
  54 static ng_constructor_t ng_device_cons;
  55 static ng_rcvmsg_t      ng_device_rcvmsg;
  56 static ng_newhook_t     ng_device_newhook;
  57 static ng_connect_t     ng_device_connect;
  58 static ng_rcvdata_t     ng_device_rcvdata;
  59 static ng_disconnect_t  ng_device_disconnect;
  60 static int              ng_device_mod_event(module_t mod, int event, void *data);
  61
  62 static int ng_device_init(void);
  63 static int get_free_unit(void);
  64
  65 /* Netgraph type */
  66 static struct ng_type typestruct = {
  67         NG_VERSION,                     /* version */
  68         NG_DEVICE_NODE_TYPE,            /* name */
  69         ng_device_mod_event,            /* modevent */
  70         ng_device_cons,                 /* constructor */
  71         ng_device_rcvmsg,               /* receive msg */
  72         NULL,                           /* shutdown */
  73         ng_device_newhook,              /* newhook */
  74         NULL,                           /* findhook */
  75         ng_device_connect,              /* connect */
  76         ng_device_rcvdata,              /* receive data */
  77         ng_device_rcvdata,              /* receive queued data */
  78         ng_device_disconnect,           /* disconnect */
  79         NULL
  80 };
  81 NETGRAPH_INIT(device, &typestruct);
  82
  83 /* per hook data */
  84 struct ngd_connection {
  85         SLIST_ENTRY(ngd_connection) links;
  86
  87         cdev_t  ngddev;
  88         struct  ng_hook *active_hook;
  89         char    *readq;
  90         int     loc;
  91         int     unit;
  92 };
  93
  94 /* global data */
  95 struct ngd_softc {
  96         SLIST_HEAD(, ngd_connection) head;
  97
  98         node_p node;
  99         char nodename[NG_NODESIZ];
 100 } ngd_softc;
 101
 102 /* helper definition */
 103 #define         MIN(a, b)       ((a) < (b) ? (a) : (b))
 104
 105 /* the per connection receiving queue maximum */
 106 #define NGD_QUEUE_SIZE (1024*10)
 107
 108 /* Maximum number of NGD devices */
 109 #define MAX_NGD 25              /* should be more than enough for now */
 110
 111 static d_close_t ngdclose;
 112 static d_open_t ngdopen;
 113 static d_read_t ngdread;
 114 static d_write_t ngdwrite;
 115 static d_ioctl_t ngdioctl;
 116 static d_poll_t ngdpoll;
 117
 118 #define NGD_CDEV_MAJOR 20
 119 static struct cdevsw ngd_cdevsw = {
 120         /* name */      "ngd",
 121         /* maj */       NGD_CDEV_MAJOR,
 122         /* flags */     0,
 123         /* port */      NULL,
 124         /* clone */     NULL,
 125
 126         /* open */      ngdopen,
 127         /* close */     ngdclose,
 128         /* read */      ngdread,
 129         /* write */     ngdwrite,
 130         /* ioctl */     ngdioctl,
 131         /* poll */      ngdpoll,
 132         /* mmap */      nommap,
 133         /* strategy */  nostrategy,
 134         /* dump */      nodump,
 135         /* psize */     nopsize
 136 };
 137
 138 /*
 139  * this holds all the stuff that should be done at load time
 140  */
 141 static int
 142 ng_device_mod_event(module_t mod, int event, void *data)
 143 {
 144         int error = 0;
 145
 146 #ifdef NGD_DEBUG
 147         kprintf("%s()\n", __func__);
 148 #endif /* NGD_DEBUG */
 149
 150         switch (event) {
 151                 case MOD_LOAD:
 152                         cdevsw_add(&ngd_cdevsw, 0, 0);
 153                         ng_device_init();
 154                         break;
 155
 156                 case MOD_UNLOAD:
 157                         /* XXX do we need to do something specific ? */
 158                         /* ng_device_breakdown */
 159                         cdevsw_remove(&ngd_cdevsw, 0, 0);
 160                         error = EBUSY; /* no unload! */
 161                         break;
 162
 163
 164                 default:
 165                         error = EOPNOTSUPP;
 166                         break;
 167         }
 168
 169         return(error);
 170 }
 171
 172
 173 static int
 174 ng_device_init(void)
 175 {
 176         struct ngd_softc *sc = &ngd_softc;
 177
 178 #ifdef NGD_DEBUG
 179         kprintf("%s()\n", __func__);
 180 #endif /* NGD_DEBUG */
 181
 182         SLIST_INIT(&sc->head);
 183
 184         if (ng_make_node_common(&typestruct, &sc->node) != 0) {
 185                 kprintf("%s(): ng_make_node_common failed\n", __func__);
 186                 return(ENXIO);
 187         }
 188         ksprintf(sc->nodename, "%s", NG_DEVICE_NODE_TYPE);
 189         if (ng_name_node(sc->node, sc->nodename)) {
 190                 NG_NODE_UNREF(sc->node); /* make it go away again */
 191                 kprintf("%s(): ng_name_node failed\n", __func__);
 192                 return(ENXIO);
 193         }
 194         NG_NODE_SET_PRIVATE(sc->node, sc);
 195
 196         return(0);
 197 }
 198
 199 /*
 200  * don't allow to be created, only the device can do that
 201  */
 202 static int
 203 ng_device_cons(node_p node)
 204 {
 205
 206 #ifdef NGD_DEBUG
 207         kprintf("%s()\n", __func__);
 208 #endif /* NGD_DEBUG */
 209
 210         return(EINVAL);
 211 }
 212
 213 /*
 214  * Receive control message. We just  free it.
 215  */
 216 static int
 217 ng_device_rcvmsg(node_p node,
 218         struct ng_mesg *msg, const char *retaddr, struct ng_mesg **rptr)
 219 {
 220         kfree(msg, M_NETGRAPH);
 221         return(ENOTTY);
 222 }
 223
 224 static int
 225 get_free_unit(void)
 226 {
 227         struct ngd_connection *tmp = NULL;
 228         struct ngd_softc *sc = &ngd_softc;
 229         int n = 0;
 230         int unit = -1;
 231
 232 #ifdef NGD_DEBUG
 233         kprintf("%s()\n", __func__);
 234 #endif /* NGD_DEBUG */
 235
 236         /* When there is no list yet, the first device unit is always 0. */
 237         if (SLIST_EMPTY(&sc->head)) {
 238                 unit = 0;
 239                 return(unit);
 240         }
 241
 242         /* Just do a brute force loop to find the first free unit that is
 243          * smaller than MAX_NGD.
 244          * Set MAX_NGD to a large value, doesn't impact performance.
 245          */
 246         for(n = 0;n<MAX_NGD && unit == -1;n++) {
 247                 SLIST_FOREACH(tmp, &sc->head, links) {
 248
 249                         if(tmp->unit == n) {
 250                                 unit = -1;
 251                                 break;
 252                         }
 253                         unit = n;
 254                 }
 255         }
 256
 257         return(unit);
 258 }
 259
 260 /*
 261  * incoming hook
 262  */
 263 static int
 264 ng_device_newhook(node_p node, hook_p hook, const char *name)
 265 {
 266         struct ngd_softc *sc = &ngd_softc;
 267         struct ngd_connection * new_connection = NULL;
 268
 269 #ifdef NGD_DEBUG
 270         kprintf("%s()\n", __func__);
 271 #endif /* NGD_DEBUG */
 272
 273         new_connection = kmalloc(sizeof(struct ngd_connection), M_DEVBUF, M_NOWAIT);
 274         if(new_connection == NULL) {
 275                 kprintf("%s(): ERROR: new_connection == NULL\n", __func__);
 276                 return(-1);
 277         }
 278
 279         new_connection->unit = get_free_unit();
 280         if(new_connection->unit<0) {
 281                 kprintf("%s: No free unit found by get_free_unit(), "
 282                                 "increas MAX_NGD\n", __func__);
 283                 kfree(new_connection, M_DEVBUF);
 284                 return(-1);
 285         }
 286         new_connection->ngddev = make_dev(&ngd_cdevsw,
 287             new_connection->unit, 0, 0, 0600, "ngd%d", new_connection->unit);
 288         if(new_connection->ngddev == NULL) {
 289                 kprintf("%s(): make_dev failed\n", __func__);
 290                 SLIST_REMOVE(&sc->head, new_connection, ngd_connection, links);
 291                 kfree(new_connection, M_DEVBUF);
 292                 return(-1);
 293         }
 294
 295         new_connection->readq =
 296             kmalloc(sizeof(char)*NGD_QUEUE_SIZE, M_DEVBUF, M_NOWAIT | M_ZERO);
 297         if(new_connection->readq == NULL) {
 298                 kprintf("%s(): readq malloc failed\n", __func__);
 299                 destroy_dev(new_connection->ngddev);
 300                 SLIST_REMOVE(&sc->head, new_connection, ngd_connection, links);
 301                 kfree(new_connection, M_DEVBUF);
 302                 return(-1);
 303         }
 304
 305         /* point to begin of buffer */
 306         new_connection->loc = 0;
 307         new_connection->active_hook = hook;
 308
 309         SLIST_INSERT_HEAD(&sc->head, new_connection, links);
 310
 311         return(0);
 312 }
 313
 314 /*
 315  * we gave ok to a new hook
 316  * now connect
 317  */
 318 static int
 319 ng_device_connect(hook_p hook)
 320 {
 321
 322 #ifdef NGD_DEBUG
 323         kprintf("%s()\n", __func__);
 324 #endif /* NGD_DEBUG */
 325
 326         return(0);
 327 }
 328
 329
 330 /*
 331  * Receive data from hook
 332  */
 333 static int
 334 ng_device_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 335 {
 336         struct ngd_softc *sc = &ngd_softc;
 337         struct ngd_connection * connection = NULL;
 338         struct ngd_connection * tmp;
 339         char *buffer;
 340
 341 #ifdef NGD_DEBUG
 342         kprintf("%s()\n", __func__);
 343 #endif /* NGD_DEBUG */
 344
 345         SLIST_FOREACH(tmp, &sc->head, links) {
 346                 if(tmp->active_hook == hook) {
 347                         connection = tmp;
 348                 }
 349         }
 350         if(connection == NULL) {
 351                 kprintf("%s(): connection still NULL, no hook found\n", __func__);
 352                 return(-1);
 353         }
 354
 355         NG_FREE_META(meta);
 356
 357         m = m_pullup(m, m->m_len);
 358         if(m == NULL) {
 359                 kprintf("%s(): ERROR: m_pullup failed\n", __func__);
 360                 return(-1);
 361         }
 362
 363         buffer = kmalloc(sizeof(char)*m->m_len, M_DEVBUF, M_NOWAIT | M_ZERO);
 364         if(buffer == NULL) {
 365                 kprintf("%s(): ERROR: buffer malloc failed\n", __func__);
 366                 return(-1);
 367         }
 368
 369         buffer = mtod(m, char *);
 370
 371         if( (connection->loc+m->m_len) < NGD_QUEUE_SIZE) {
 372                 memcpy(connection->readq+connection->loc, buffer, m->m_len);
 373                 connection->loc += m->m_len;
 374         } else
 375                 kprintf("%s(): queue full, first read out a bit\n", __func__);
 376
 377         kfree(buffer, M_DEVBUF);
 378
 379         return(0);
 380 }
 381
 382 /*
 383  * Removal of the last link destroys the node
 384  */
 385 static int
 386 ng_device_disconnect(hook_p hook)
 387 {
 388         struct ngd_softc *sc = &ngd_softc;
 389         struct ngd_connection * connection = NULL;
 390         struct ngd_connection * tmp;
 391
 392 #ifdef NGD_DEBUG
 393         kprintf("%s()\n", __func__);
 394 #endif /* NGD_DEBUG */
 395
 396         SLIST_FOREACH(tmp, &sc->head, links) {
 397                 if(tmp->active_hook == hook) {
 398                         connection = tmp;
 399                 }
 400         }
 401         if(connection == NULL) {
 402                 kprintf("%s(): connection still NULL, no hook found\n",
 403                     __func__);
 404                 return(-1);
 405         }
 406
 407         kfree(connection->readq, M_DEVBUF);
 408
 409         destroy_dev(connection->ngddev);
 410
 411         SLIST_REMOVE(&sc->head, connection, ngd_connection, links);
 412
 413         return(0);
 414 }
 415 /*
 416  * the device is opened
 417  */
 418 static int
 419 ngdopen(cdev_t dev, int flag, int mode, struct thread *td)
 420 {
 421
 422 #ifdef NGD_DEBUG
 423         kprintf("%s()\n", __func__);
 424 #endif /* NGD_DEBUG */
 425
 426         return(0);
 427 }
 428
 429 /*
 430  * the device is closed
 431  */
 432 static int
 433 ngdclose(cdev_t dev, int flag, int mode, struct thread *td)
 434 {
 435
 436 #ifdef NGD_DEBUG
 437         kprintf("%s()\n", __func__);
 438 #endif
 439
 440         return(0);
 441 }
 442
 443
 444 /*
 445  * process ioctl
 446  *
 447  * they are translated into netgraph messages and passed on
 448  *
 449  */
 450 static int
 451 ngdioctl(cdev_t dev, u_long cmd, caddr_t addr, int flag, struct thread *td)
 452 {
 453         struct ngd_softc *sc = &ngd_softc;
 454         struct ngd_connection * connection = NULL;
 455         struct ngd_connection * tmp;
 456         int error = 0;
 457         struct ng_mesg *msg;
 458         struct ngd_param_s * datap;
 459
 460 #ifdef NGD_DEBUG
 461         kprintf("%s()\n", __func__);
 462 #endif /* NGD_DEBUG */
 463
 464         SLIST_FOREACH(tmp, &sc->head, links) {
 465                 if(tmp->ngddev == dev) {
 466                         connection = tmp;
 467                 }
 468         }
 469         if(connection == NULL) {
 470                 kprintf("%s(): connection still NULL, no dev found\n",
 471                     __func__);
 472                 return(-1);
 473         }
 474
 475         /* NG_MKMESSAGE(msg, cookie, cmdid, len, how) */
 476         NG_MKMESSAGE(msg, NGM_DEVICE_COOKIE, cmd, sizeof(struct ngd_param_s),
 477                         M_NOWAIT);
 478         if (msg == NULL) {
 479                 kprintf("%s(): msg == NULL\n", __func__);
 480                 goto nomsg;
 481         }
 482
 483         /* pass the ioctl data into the ->data area */
 484         datap = (struct ngd_param_s *)msg->data;
 485         datap->p = addr;
 486
 487         /*ng_send_msg(node_p here, struct ng_mesg *msg,
 488                     const char *address, struct ng_mesg **resp); */
 489         error = ng_send_msg(sc->node, msg,
 490             NG_HOOK_NAME(connection->active_hook), NULL);
 491         if(error)
 492                 kprintf("%s(): ng_send_msg() error: %d\n", __func__, error);
 493
 494 nomsg:
 495
 496         return(0);
 497 }
 498
 499
 500 /*
 501  * This function is called when a read(2) is done to our device.
 502  * We pass the data available in kernelspace on into userland using
 503  * uiomove.
 504  */
 505 static int
 506 ngdread(cdev_t dev, struct uio *uio, int flag)
 507 {
 508         int ret = 0, amnt;
 509         char buffer[uio->uio_resid+1];
 510         struct ngd_softc *sc = &ngd_softc;
 511         struct ngd_connection * connection = NULL;
 512         struct ngd_connection * tmp;
 513
 514 #ifdef NGD_DEBUG
 515         kprintf("%s()\n", __func__);
 516 #endif /* NGD_DEBUG */
 517
 518         SLIST_FOREACH(tmp, &sc->head, links) {
 519                 if(tmp->ngddev == dev) {
 520                         connection = tmp;
 521                 }
 522         }
 523         if(connection == NULL) {
 524                 kprintf("%s(): connection still NULL, no dev found\n", __func__);
 525                 return(-1);
 526         }
 527
 528         while ( ( uio->uio_resid > 0 ) && ( connection->loc > 0 ) ) {
 529                 amnt = MIN(uio->uio_resid, connection->loc);
 530
 531                 memcpy(buffer, connection->readq, amnt);
 532                 memcpy(connection->readq, connection->readq+amnt,
 533                                 connection->loc-amnt);
 534                 connection->loc -= amnt;
 535
 536                 ret = uiomove((caddr_t)buffer, amnt, uio);
 537                 if(ret != 0)
 538                         goto error;
 539
 540         }
 541         return(0);
 542
 543 error:
 544         kprintf("%s(): uiomove returns error %d\n", __func__, ret);
 545         /* do error cleanup here */
 546         return(ret);
 547 }
 548
 549
 550 /*
 551  * This function is called when our device is written to.
 552  * We read the data from userland into our local buffer and pass it on
 553  * into the remote hook.
 554  *
 555  */
 556 static int
 557 ngdwrite(cdev_t dev, struct uio *uio, int flag)
 558 {
 559         int ret;
 560         int error = 0;
 561         struct mbuf *m;
 562         char buffer[uio->uio_resid];
 563         int len = uio->uio_resid;
 564         struct ngd_softc *sc =& ngd_softc;
 565         struct ngd_connection * connection = NULL;
 566         struct ngd_connection * tmp;
 567
 568 #ifdef NGD_DEBUG
 569         kprintf("%s()\n", __func__);
 570 #endif /* NGD_DEBUG */
 571
 572         SLIST_FOREACH(tmp, &sc->head, links) {
 573                 if(tmp->ngddev == dev) {
 574                         connection = tmp;
 575                 }
 576         }
 577
 578         if(connection == NULL) {
 579                 kprintf("%s(): connection still NULL, no dev found\n", __func__);
 580                 return(-1);
 581         }
 582
 583         if (len > 0) {
 584                 if ((ret = uiomove((caddr_t)buffer, len, uio)) != 0)
 585                         goto error;
 586         } else
 587                 kprintf("%s(): len <= 0 : supposed to happen?!\n", __func__);
 588
 589         m = m_devget(buffer, len, 0, NULL, NULL);
 590
 591         NG_SEND_DATA_ONLY(error, connection->active_hook, m);
 592
 593         return(0);
 594
 595 error:
 596         /* do error cleanup here */
 597         kprintf("%s(): uiomove returned err: %d\n", __func__, ret);
 598
 599         return(ret);
 600 }
 601
 602 /*
 603  * we are being polled/selected
 604  * check if there is data available for read
 605  */
 606 static int
 607 ngdpoll(cdev_t dev, int events, struct thread *td)
 608 {
 609         int revents = 0;
 610         struct ngd_softc *sc = &ngd_softc;
 611         struct ngd_connection * connection = NULL;
 612         struct ngd_connection * tmp;
 613
 614
 615         if (events & (POLLIN | POLLRDNORM)) {
 616                 /* get the connection we have to know the loc from */
 617                 SLIST_FOREACH(tmp, &sc->head, links) {
 618                         if(tmp->ngddev == dev) {
 619                                 connection = tmp;
 620                         }
 621                 }
 622                 if(connection == NULL) {
 623                         kprintf("%s(): ERROR: connection still NULL, "
 624                                 "no dev found\n", __func__);
 625                         return(-1);
 626                 }
 627
 628                 if (connection->loc > 0)
 629                         revents |= events & (POLLIN | POLLRDNORM);
 630         }
 631
 632         return(revents);
 633 }