Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_device.c
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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 }
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