ng_tty.c revision 186059
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 186059 2008-12-13 22:05:46Z 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#include <sys/proc.h> 77 78#include <net/if.h> 79#include <net/if_var.h> 80 81#include <netgraph/ng_message.h> 82#include <netgraph/netgraph.h> 83#include <netgraph/ng_tty.h> 84 85/* Per-node private info */ 86struct ngt_softc { 87 struct tty *tp; /* Terminal device */ 88 node_p node; /* Netgraph node */ 89 hook_p hook; /* Netgraph hook */ 90 struct ifqueue outq; /* Queue of outgoing data */ 91 size_t outqlen; /* Number of bytes in outq */ 92 struct mbuf *m; /* Incoming non-bypass data buffer */ 93 short hotchar; /* Hotchar, or -1 if none */ 94 u_int flags; /* Flags */ 95}; 96typedef struct ngt_softc *sc_p; 97 98/* Flags */ 99#define FLG_DEBUG 0x0002 100 101/* Netgraph methods */ 102static ng_constructor_t ngt_constructor; 103static ng_rcvmsg_t ngt_rcvmsg; 104static ng_shutdown_t ngt_shutdown; 105static ng_newhook_t ngt_newhook; 106static ng_connect_t ngt_connect; 107static ng_rcvdata_t ngt_rcvdata; 108static ng_disconnect_t ngt_disconnect; 109 110#define ERROUT(x) do { error = (x); goto done; } while (0) 111 112static th_getc_inject_t ngt_getc_inject; 113static th_getc_poll_t ngt_getc_poll; 114static th_rint_t ngt_rint; 115static th_rint_bypass_t ngt_rint_bypass; 116static th_rint_poll_t ngt_rint_poll; 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}; 125 126/* Netgraph node type descriptor */ 127static struct ng_type typestruct = { 128 .version = NG_ABI_VERSION, 129 .name = NG_TTY_NODE_TYPE, 130 .constructor = ngt_constructor, 131 .rcvmsg = ngt_rcvmsg, 132 .shutdown = ngt_shutdown, 133 .newhook = ngt_newhook, 134 .connect = ngt_connect, 135 .rcvdata = ngt_rcvdata, 136 .disconnect = ngt_disconnect, 137}; 138NETGRAPH_INIT(tty, &typestruct); 139 140#define NGTLOCK(sc) IF_LOCK(&sc->outq) 141#define NGTUNLOCK(sc) IF_UNLOCK(&sc->outq) 142 143/****************************************************************** 144 NETGRAPH NODE METHODS 145******************************************************************/ 146 147/* 148 * Initialize a new node of this type. 149 * 150 * We only allow nodes to be created as a result of setting 151 * the line discipline on a tty, so always return an error if not. 152 */ 153static int 154ngt_constructor(node_p node) 155{ 156 sc_p sc; 157 158 /* Allocate private structure */ 159 sc = malloc(sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO); 160 if (sc == NULL) 161 return (ENOMEM); 162 163 NG_NODE_SET_PRIVATE(node, sc); 164 sc->node = node; 165 166 mtx_init(&sc->outq.ifq_mtx, "ng_tty node+queue", NULL, MTX_DEF); 167 IFQ_SET_MAXLEN(&sc->outq, IFQ_MAXLEN); 168 169 return (0); 170} 171 172/* 173 * Add a new hook. There can only be one. 174 */ 175static int 176ngt_newhook(node_p node, hook_p hook, const char *name) 177{ 178 const sc_p sc = NG_NODE_PRIVATE(node); 179 180 if (strcmp(name, NG_TTY_HOOK)) 181 return (EINVAL); 182 183 if (sc->hook) 184 return (EISCONN); 185 186 NGTLOCK(sc); 187 sc->hook = hook; 188 NGTUNLOCK(sc); 189 190 return (0); 191} 192 193/* 194 * Set the hook into queueing mode (for outgoing packets), 195 * so that we wont deliver mbuf thru the whole graph holding 196 * tty locks. 197 */ 198static int 199ngt_connect(hook_p hook) 200{ 201 NG_HOOK_FORCE_QUEUE(hook); 202 return (0); 203} 204 205/* 206 * Disconnect the hook 207 */ 208static int 209ngt_disconnect(hook_p hook) 210{ 211 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 212 213 if (hook != sc->hook) 214 panic(__func__); 215 216 NGTLOCK(sc); 217 sc->hook = NULL; 218 NGTUNLOCK(sc); 219 220 return (0); 221} 222 223/* 224 * Remove this node. The does the netgraph portion of the shutdown. 225 */ 226static int 227ngt_shutdown(node_p node) 228{ 229 const sc_p sc = NG_NODE_PRIVATE(node); 230 struct tty *tp; 231 232 tp = sc->tp; 233 if (tp != NULL) { 234 tty_lock(tp); 235 ttyhook_unregister(tp); 236 } 237 /* Free resources */ 238 IF_DRAIN(&sc->outq); 239 mtx_destroy(&(sc)->outq.ifq_mtx); 240 NG_NODE_UNREF(sc->node); 241 free(sc, M_NETGRAPH); 242 243 return (0); 244} 245 246/* 247 * Receive control message 248 */ 249static int 250ngt_rcvmsg(node_p node, item_p item, hook_p lasthook) 251{ 252 struct proc *p; 253 const sc_p sc = NG_NODE_PRIVATE(node); 254 struct ng_mesg *msg, *resp = NULL; 255 int error = 0; 256 257 NGI_GET_MSG(item, msg); 258 switch (msg->header.typecookie) { 259 case NGM_TTY_COOKIE: 260 switch (msg->header.cmd) { 261 case NGM_TTY_SET_TTY: 262 if (sc->tp != NULL) 263 return (EBUSY); 264 265 p = pfind(((int *)msg->data)[0]); 266 if (p == NULL || (p->p_flag & P_WEXIT)) 267 return (ESRCH); 268 _PHOLD(p); 269 PROC_UNLOCK(p); 270 error = ttyhook_register(&sc->tp, p, ((int *)msg->data)[1], 271 &ngt_hook, sc); 272 PRELE(p); 273 if (error != 0) 274 return (error); 275 break; 276 case NGM_TTY_SET_HOTCHAR: 277 { 278 int hotchar; 279 280 if (msg->header.arglen != sizeof(int)) 281 ERROUT(EINVAL); 282 hotchar = *((int *) msg->data); 283 if (hotchar != (u_char) hotchar && hotchar != -1) 284 ERROUT(EINVAL); 285 sc->hotchar = hotchar; /* race condition is OK */ 286 break; 287 } 288 case NGM_TTY_GET_HOTCHAR: 289 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 290 if (!resp) 291 ERROUT(ENOMEM); 292 /* Race condition here is OK */ 293 *((int *) resp->data) = sc->hotchar; 294 break; 295 default: 296 ERROUT(EINVAL); 297 } 298 break; 299 default: 300 ERROUT(EINVAL); 301 } 302done: 303 NG_RESPOND_MSG(error, node, item, resp); 304 NG_FREE_MSG(msg); 305 return (error); 306} 307 308/* 309 * Receive incoming data from netgraph system. Put it on our 310 * output queue and start output if necessary. 311 */ 312static int 313ngt_rcvdata(hook_p hook, item_p item) 314{ 315 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 316 struct tty *tp = sc->tp; 317 struct mbuf *m; 318 319 if (hook != sc->hook) 320 panic(__func__); 321 322 NGI_GET_M(item, m); 323 NG_FREE_ITEM(item); 324 325 if (tp == NULL) { 326 NG_FREE_M(m); 327 return (ENXIO); 328 } 329 330 IF_LOCK(&sc->outq); 331 if (_IF_QFULL(&sc->outq)) { 332 _IF_DROP(&sc->outq); 333 IF_UNLOCK(&sc->outq); 334 NG_FREE_M(m); 335 return (ENOBUFS); 336 } 337 338 _IF_ENQUEUE(&sc->outq, m); 339 sc->outqlen += m->m_pkthdr.len; 340 IF_UNLOCK(&sc->outq); 341 342 /* notify the TTY that data is ready */ 343 tty_lock(tp); 344 if (!tty_gone(tp)) 345 ttydevsw_outwakeup(tp); 346 tty_unlock(tp); 347 348 return (0); 349} 350 351static size_t 352ngt_getc_inject(struct tty *tp, void *buf, size_t len) 353{ 354 sc_p sc = ttyhook_softc(tp); 355 size_t total = 0; 356 int length; 357 358 while (len) { 359 struct mbuf *m; 360 361 /* Remove first mbuf from queue */ 362 IF_DEQUEUE(&sc->outq, m); 363 if (m == NULL) 364 break; 365 366 /* Send as much of it as possible */ 367 while (m != NULL) { 368 length = min(m->m_len, len); 369 memcpy((char *)buf + total, mtod(m, char *), length); 370 371 m->m_data += length; 372 m->m_len -= length; 373 total += length; 374 len -= length; 375 376 if (m->m_len > 0) 377 break; /* device can't take any more */ 378 m = m_free(m); 379 } 380 381 /* Put remainder of mbuf chain (if any) back on queue */ 382 if (m != NULL) { 383 IF_PREPEND(&sc->outq, m); 384 break; 385 } 386 } 387 IF_LOCK(&sc->outq); 388 sc->outqlen -= total; 389 IF_UNLOCK(&sc->outq); 390 MPASS(sc->outqlen >= 0); 391 392 return (total); 393} 394 395static size_t 396ngt_getc_poll(struct tty *tp) 397{ 398 sc_p sc = ttyhook_softc(tp); 399 400 return (sc->outqlen); 401} 402 403/* 404 * Optimised TTY input. 405 * 406 * We get a buffer pointer to hopefully a complete data frame. Do not check for 407 * the hotchar, just pass it on. 408 */ 409static size_t 410ngt_rint_bypass(struct tty *tp, const void *buf, size_t len) 411{ 412 sc_p sc = ttyhook_softc(tp); 413 node_p node = sc->node; 414 struct mbuf *m, *mb; 415 size_t total = 0; 416 int error = 0, length; 417 418 tty_lock_assert(tp, MA_OWNED); 419 420 if (sc->hook == NULL) 421 return (0); 422 423 m = m_getm2(NULL, len, M_DONTWAIT, MT_DATA, M_PKTHDR); 424 if (m == NULL) { 425 if (sc->flags & FLG_DEBUG) 426 log(LOG_ERR, 427 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 428 return (0); 429 } 430 m->m_pkthdr.rcvif = NULL; 431 432 for (mb = m; mb != NULL; mb = mb->m_next) { 433 length = min(M_TRAILINGSPACE(mb), len - total); 434 435 memcpy(mtod(m, char *), (const char *)buf + total, length); 436 mb->m_len = length; 437 total += length; 438 m->m_pkthdr.len += length; 439 } 440 if (sc->m != NULL) { 441 /* 442 * Odd, we have changed from non-bypass to bypass. It is 443 * unlikely but not impossible, flush the data first. 444 */ 445 sc->m->m_data = sc->m->m_pktdat; 446 NG_SEND_DATA_ONLY(error, sc->hook, sc->m); 447 sc->m = NULL; 448 } 449 NG_SEND_DATA_ONLY(error, sc->hook, m); 450 451 return (total); 452} 453 454/* 455 * Receive data coming from the device one char at a time, when it is not in 456 * bypass mode. 457 */ 458static int 459ngt_rint(struct tty *tp, char c, int flags) 460{ 461 sc_p sc = ttyhook_softc(tp); 462 node_p node = sc->node; 463 struct mbuf *m; 464 int error = 0; 465 466 tty_lock_assert(tp, MA_OWNED); 467 468 if (sc->hook == NULL) 469 return (0); 470 471 if (flags != 0) { 472 /* framing error or overrun on this char */ 473 if (sc->flags & FLG_DEBUG) 474 log(LOG_DEBUG, "%s: line error %x\n", 475 NG_NODE_NAME(node), flags); 476 return (0); 477 } 478 479 /* Get a new header mbuf if we need one */ 480 if (!(m = sc->m)) { 481 MGETHDR(m, M_DONTWAIT, MT_DATA); 482 if (!m) { 483 if (sc->flags & FLG_DEBUG) 484 log(LOG_ERR, 485 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 486 return (ENOBUFS); 487 } 488 m->m_len = m->m_pkthdr.len = 0; 489 m->m_pkthdr.rcvif = NULL; 490 sc->m = m; 491 } 492 493 /* Add char to mbuf */ 494 *mtod(m, u_char *) = c; 495 m->m_data++; 496 m->m_len++; 497 m->m_pkthdr.len++; 498 499 /* Ship off mbuf if it's time */ 500 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 501 m->m_data = m->m_pktdat; 502 sc->m = NULL; 503 NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */ 504 } 505 506 return (error); 507} 508 509static size_t 510ngt_rint_poll(struct tty *tp) 511{ 512 /* We can always accept input */ 513 return (1); 514} 515 516