ng_tty.c revision 184752
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 * 42 * $FreeBSD: head/sys/netgraph/ng_tty.c 184752 2008-11-07 19:51:07Z mav $ 43 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $ 44 */ 45 46/* 47 * This file implements TTY hooks to link in to the netgraph system. The node 48 * is created and then passed the callers opened TTY file descriptor number to 49 * NGM_TTY_SET_TTY, this will hook the tty via ttyhook_register(). 50 * 51 * Incoming data is delivered directly to ng_tty via the TTY bypass hook as a 52 * buffer pointer and length, this is converted to a mbuf and passed to the 53 * peer. 54 * 55 * If the TTY device does not support bypass then incoming characters are 56 * delivered to the hook one at a time, each in its own mbuf. You may 57 * optionally define a ``hotchar,'' which causes incoming characters to be 58 * buffered up until either the hotchar is seen or the mbuf is full (MHLEN 59 * bytes). Then all buffered characters are immediately delivered. 60 */ 61 62#include <sys/param.h> 63#include <sys/systm.h> 64#include <sys/conf.h> 65#include <sys/errno.h> 66#include <sys/fcntl.h> 67#include <sys/ioccom.h> 68#include <sys/kernel.h> 69#include <sys/malloc.h> 70#include <sys/mbuf.h> 71#include <sys/priv.h> 72#include <sys/socket.h> 73#include <sys/syslog.h> 74#include <sys/tty.h> 75#include <sys/ttycom.h> 76 77#include <net/if.h> 78#include <net/if_var.h> 79 80#include <netgraph/ng_message.h> 81#include <netgraph/netgraph.h> 82#include <netgraph/ng_tty.h> 83 84/* Per-node private info */ 85struct ngt_softc { 86 struct tty *tp; /* Terminal device */ 87 node_p node; /* Netgraph node */ 88 hook_p hook; /* Netgraph hook */ 89 struct ifqueue outq; /* Queue of outgoing data */ 90 size_t outqlen; /* Number of bytes in outq */ 91 struct mbuf *m; /* Incoming non-bypass data buffer */ 92 short hotchar; /* Hotchar, or -1 if none */ 93 u_int flags; /* Flags */ 94}; 95typedef struct ngt_softc *sc_p; 96 97/* Flags */ 98#define FLG_DEBUG 0x0002 99 100/* Netgraph methods */ 101static ng_constructor_t ngt_constructor; 102static ng_rcvmsg_t ngt_rcvmsg; 103static ng_shutdown_t ngt_shutdown; 104static ng_newhook_t ngt_newhook; 105static ng_connect_t ngt_connect; 106static ng_rcvdata_t ngt_rcvdata; 107static ng_disconnect_t ngt_disconnect; 108 109#define ERROUT(x) do { error = (x); goto done; } while (0) 110 111static th_getc_inject_t ngt_getc_inject; 112static th_getc_poll_t ngt_getc_poll; 113static th_rint_t ngt_rint; 114static th_rint_bypass_t ngt_rint_bypass; 115static th_rint_poll_t ngt_rint_poll; 116static th_close_t ngt_close; 117 118static struct ttyhook ngt_hook = { 119 .th_getc_inject = ngt_getc_inject, 120 .th_getc_poll = ngt_getc_poll, 121 .th_rint = ngt_rint, 122 .th_rint_bypass = ngt_rint_bypass, 123 .th_rint_poll = ngt_rint_poll, 124 .th_close = ngt_close, 125}; 126 127/* Netgraph node type descriptor */ 128static struct ng_type typestruct = { 129 .version = NG_ABI_VERSION, 130 .name = NG_TTY_NODE_TYPE, 131 .constructor = ngt_constructor, 132 .rcvmsg = ngt_rcvmsg, 133 .shutdown = ngt_shutdown, 134 .newhook = ngt_newhook, 135 .connect = ngt_connect, 136 .rcvdata = ngt_rcvdata, 137 .disconnect = ngt_disconnect, 138}; 139NETGRAPH_INIT(tty, &typestruct); 140 141#define NGTLOCK(sc) IF_LOCK(&sc->outq) 142#define NGTUNLOCK(sc) IF_UNLOCK(&sc->outq) 143 144/****************************************************************** 145 NETGRAPH NODE METHODS 146******************************************************************/ 147 148/* 149 * Initialize a new node of this type. 150 * 151 * We only allow nodes to be created as a result of setting 152 * the line discipline on a tty, so always return an error if not. 153 */ 154static int 155ngt_constructor(node_p node) 156{ 157 sc_p sc; 158 159 /* Allocate private structure */ 160 sc = malloc(sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO); 161 if (sc == NULL) 162 return (ENOMEM); 163 164 NG_NODE_SET_PRIVATE(node, sc); 165 sc->node = node; 166 167 mtx_init(&sc->outq.ifq_mtx, "ng_tty node+queue", NULL, MTX_DEF); 168 IFQ_SET_MAXLEN(&sc->outq, IFQ_MAXLEN); 169 170 return (0); 171} 172 173/* 174 * Add a new hook. There can only be one. 175 */ 176static int 177ngt_newhook(node_p node, hook_p hook, const char *name) 178{ 179 const sc_p sc = NG_NODE_PRIVATE(node); 180 181 if (strcmp(name, NG_TTY_HOOK)) 182 return (EINVAL); 183 184 if (sc->hook) 185 return (EISCONN); 186 187 NGTLOCK(sc); 188 sc->hook = hook; 189 NGTUNLOCK(sc); 190 191 return (0); 192} 193 194/* 195 * Set the hook into queueing mode (for outgoing packets), 196 * so that we wont deliver mbuf thru the whole graph holding 197 * tty locks. 198 */ 199static int 200ngt_connect(hook_p hook) 201{ 202 NG_HOOK_FORCE_QUEUE(hook); 203 return (0); 204} 205 206/* 207 * Disconnect the hook 208 */ 209static int 210ngt_disconnect(hook_p hook) 211{ 212 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 213 214 if (hook != sc->hook) 215 panic(__func__); 216 217 NGTLOCK(sc); 218 sc->hook = NULL; 219 NGTUNLOCK(sc); 220 221 return (0); 222} 223 224/* 225 * Remove this node. The does the netgraph portion of the shutdown. 226 */ 227static int 228ngt_shutdown(node_p node) 229{ 230 const sc_p sc = NG_NODE_PRIVATE(node); 231 struct tty *tp; 232 233 tp = sc->tp; 234 if (tp != NULL) { 235 tty_lock(tp); 236 ttyhook_unregister(tp); 237 } 238 /* Free resources */ 239 IF_DRAIN(&sc->outq); 240 mtx_destroy(&(sc)->outq.ifq_mtx); 241 NG_NODE_UNREF(sc->node); 242 free(sc, M_NETGRAPH); 243 244 return (0); 245} 246 247/* 248 * Receive control message 249 */ 250static int 251ngt_rcvmsg(node_p node, item_p item, hook_p lasthook) 252{ 253 struct thread *td = curthread; /* XXX */ 254 const sc_p sc = NG_NODE_PRIVATE(node); 255 struct ng_mesg *msg, *resp = NULL; 256 int error = 0; 257 258 NGI_GET_MSG(item, msg); 259 switch (msg->header.typecookie) { 260 case NGM_TTY_COOKIE: 261 switch (msg->header.cmd) { 262 case NGM_TTY_SET_TTY: 263 if (sc->tp != NULL) 264 return (EBUSY); 265 error = ttyhook_register(&sc->tp, td, *(int *)msg->data, 266 &ngt_hook, sc); 267 if (error != 0) 268 return (error); 269 break; 270 case NGM_TTY_SET_HOTCHAR: 271 { 272 int hotchar; 273 274 if (msg->header.arglen != sizeof(int)) 275 ERROUT(EINVAL); 276 hotchar = *((int *) msg->data); 277 if (hotchar != (u_char) hotchar && hotchar != -1) 278 ERROUT(EINVAL); 279 sc->hotchar = hotchar; /* race condition is OK */ 280 break; 281 } 282 case NGM_TTY_GET_HOTCHAR: 283 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 284 if (!resp) 285 ERROUT(ENOMEM); 286 /* Race condition here is OK */ 287 *((int *) resp->data) = sc->hotchar; 288 break; 289 default: 290 ERROUT(EINVAL); 291 } 292 break; 293 default: 294 ERROUT(EINVAL); 295 } 296done: 297 NG_RESPOND_MSG(error, node, item, resp); 298 NG_FREE_MSG(msg); 299 return (error); 300} 301 302/* 303 * Receive incoming data from netgraph system. Put it on our 304 * output queue and start output if necessary. 305 */ 306static int 307ngt_rcvdata(hook_p hook, item_p item) 308{ 309 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 310 struct tty *tp = sc->tp; 311 struct mbuf *m; 312 313 if (hook != sc->hook) 314 panic(__func__); 315 316 NGI_GET_M(item, m); 317 NG_FREE_ITEM(item); 318 319 if (tp == NULL) { 320 NG_FREE_M(m); 321 return (ENXIO); 322 } 323 324 IF_LOCK(&sc->outq); 325 if (_IF_QFULL(&sc->outq)) { 326 _IF_DROP(&sc->outq); 327 IF_UNLOCK(&sc->outq); 328 NG_FREE_M(m); 329 return (ENOBUFS); 330 } 331 332 _IF_ENQUEUE(&sc->outq, m); 333 sc->outqlen += m->m_pkthdr.len; 334 IF_UNLOCK(&sc->outq); 335 336 /* notify the TTY that data is ready */ 337 tty_lock(tp); 338 if (!tty_gone(tp)) 339 ttydevsw_outwakeup(tp); 340 tty_unlock(tp); 341 342 return (0); 343} 344 345static size_t 346ngt_getc_inject(struct tty *tp, void *buf, size_t len) 347{ 348 sc_p sc = ttyhook_softc(tp); 349 size_t total = 0; 350 int length; 351 352 while (len) { 353 struct mbuf *m; 354 355 /* Remove first mbuf from queue */ 356 IF_DEQUEUE(&sc->outq, m); 357 if (m == NULL) 358 break; 359 360 /* Send as much of it as possible */ 361 while (m != NULL) { 362 length = min(m->m_len, len); 363 memcpy((char *)buf + total, mtod(m, char *), length); 364 365 m->m_data += length; 366 m->m_len -= length; 367 total += length; 368 len -= length; 369 370 if (m->m_len > 0) 371 break; /* device can't take any more */ 372 m = m_free(m); 373 } 374 375 /* Put remainder of mbuf chain (if any) back on queue */ 376 if (m != NULL) { 377 IF_PREPEND(&sc->outq, m); 378 break; 379 } 380 } 381 IF_LOCK(&sc->outq); 382 sc->outqlen -= total; 383 IF_UNLOCK(&sc->outq); 384 MPASS(sc->outqlen >= 0); 385 386 return (total); 387} 388 389static size_t 390ngt_getc_poll(struct tty *tp) 391{ 392 sc_p sc = ttyhook_softc(tp); 393 394 return (sc->outqlen); 395} 396 397/* 398 * Optimised TTY input. 399 * 400 * We get a buffer pointer to hopefully a complete data frame. Do not check for 401 * the hotchar, just pass it on. 402 */ 403static size_t 404ngt_rint_bypass(struct tty *tp, const void *buf, size_t len) 405{ 406 sc_p sc = ttyhook_softc(tp); 407 node_p node = sc->node; 408 struct mbuf *m, *mb; 409 size_t total = 0; 410 int error = 0, length; 411 412 tty_lock_assert(tp, MA_OWNED); 413 414 if (sc->hook == NULL) 415 return (0); 416 417 m = m_getm2(NULL, len, M_DONTWAIT, MT_DATA, M_PKTHDR); 418 if (m == NULL) { 419 if (sc->flags & FLG_DEBUG) 420 log(LOG_ERR, 421 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 422 return (0); 423 } 424 m->m_pkthdr.rcvif = NULL; 425 426 for (mb = m; mb != NULL; mb = mb->m_next) { 427 length = min(M_TRAILINGSPACE(mb), len - total); 428 429 memcpy(mtod(m, char *), (const char *)buf + total, length); 430 mb->m_len = length; 431 total += length; 432 m->m_pkthdr.len += length; 433 } 434 if (sc->m != NULL) { 435 /* 436 * Odd, we have changed from non-bypass to bypass. It is 437 * unlikely but not impossible, flush the data first. 438 */ 439 sc->m->m_data = sc->m->m_pktdat; 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 */ 452static int 453ngt_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_lock_assert(tp, MA_OWNED); 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_DONTWAIT, 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 m->m_data = m->m_pktdat; 496 sc->m = NULL; 497 NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */ 498 } 499 500 return (error); 501} 502 503static size_t 504ngt_rint_poll(struct tty *tp) 505{ 506 /* We can always accept input */ 507 return (1); 508} 509 510static void 511ngt_close(struct tty *tp) 512{ 513 sc_p sc = ttyhook_softc(tp); 514 515 /* Must be queued to drop the tty lock */ 516 ng_rmnode_flags(sc->node, NG_QUEUE); 517} 518 519