ng_tty.c revision 271856
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 271856 2014-09-19 09:01:19Z glebius $ 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_WAITOK | M_ZERO); 160 161 NG_NODE_SET_PRIVATE(node, sc); 162 sc->node = node; 163 164 mtx_init(&sc->outq.ifq_mtx, "ng_tty node+queue", NULL, MTX_DEF); 165 IFQ_SET_MAXLEN(&sc->outq, ifqmaxlen); 166 167 return (0); 168} 169 170/* 171 * Add a new hook. There can only be one. 172 */ 173static int 174ngt_newhook(node_p node, hook_p hook, const char *name) 175{ 176 const sc_p sc = NG_NODE_PRIVATE(node); 177 178 if (strcmp(name, NG_TTY_HOOK)) 179 return (EINVAL); 180 181 if (sc->hook) 182 return (EISCONN); 183 184 NGTLOCK(sc); 185 sc->hook = hook; 186 NGTUNLOCK(sc); 187 188 return (0); 189} 190 191/* 192 * Set the hook into queueing mode (for outgoing packets), 193 * so that we wont deliver mbuf thru the whole graph holding 194 * tty locks. 195 */ 196static int 197ngt_connect(hook_p hook) 198{ 199 NG_HOOK_FORCE_QUEUE(hook); 200 return (0); 201} 202 203/* 204 * Disconnect the hook 205 */ 206static int 207ngt_disconnect(hook_p hook) 208{ 209 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 210 211 if (hook != sc->hook) 212 panic("%s", __func__); 213 214 NGTLOCK(sc); 215 sc->hook = NULL; 216 NGTUNLOCK(sc); 217 218 return (0); 219} 220 221/* 222 * Remove this node. The does the netgraph portion of the shutdown. 223 */ 224static int 225ngt_shutdown(node_p node) 226{ 227 const sc_p sc = NG_NODE_PRIVATE(node); 228 struct tty *tp; 229 230 tp = sc->tp; 231 if (tp != NULL) { 232 tty_lock(tp); 233 ttyhook_unregister(tp); 234 } 235 /* Free resources */ 236 IF_DRAIN(&sc->outq); 237 mtx_destroy(&(sc)->outq.ifq_mtx); 238 NG_NODE_UNREF(sc->node); 239 free(sc, M_NETGRAPH); 240 241 return (0); 242} 243 244/* 245 * Receive control message 246 */ 247static int 248ngt_rcvmsg(node_p node, item_p item, hook_p lasthook) 249{ 250 struct proc *p; 251 const sc_p sc = NG_NODE_PRIVATE(node); 252 struct ng_mesg *msg, *resp = NULL; 253 int error = 0; 254 255 NGI_GET_MSG(item, msg); 256 switch (msg->header.typecookie) { 257 case NGM_TTY_COOKIE: 258 switch (msg->header.cmd) { 259 case NGM_TTY_SET_TTY: 260 if (sc->tp != NULL) 261 return (EBUSY); 262 263 p = pfind(((int *)msg->data)[0]); 264 if (p == NULL || (p->p_flag & P_WEXIT)) 265 return (ESRCH); 266 _PHOLD(p); 267 PROC_UNLOCK(p); 268 error = ttyhook_register(&sc->tp, p, ((int *)msg->data)[1], 269 &ngt_hook, sc); 270 PRELE(p); 271 if (error != 0) 272 return (error); 273 break; 274 case NGM_TTY_SET_HOTCHAR: 275 { 276 int hotchar; 277 278 if (msg->header.arglen != sizeof(int)) 279 ERROUT(EINVAL); 280 hotchar = *((int *) msg->data); 281 if (hotchar != (u_char) hotchar && hotchar != -1) 282 ERROUT(EINVAL); 283 sc->hotchar = hotchar; /* race condition is OK */ 284 break; 285 } 286 case NGM_TTY_GET_HOTCHAR: 287 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT); 288 if (!resp) 289 ERROUT(ENOMEM); 290 /* Race condition here is OK */ 291 *((int *) resp->data) = sc->hotchar; 292 break; 293 default: 294 ERROUT(EINVAL); 295 } 296 break; 297 default: 298 ERROUT(EINVAL); 299 } 300done: 301 NG_RESPOND_MSG(error, node, item, resp); 302 NG_FREE_MSG(msg); 303 return (error); 304} 305 306/* 307 * Receive incoming data from netgraph system. Put it on our 308 * output queue and start output if necessary. 309 */ 310static int 311ngt_rcvdata(hook_p hook, item_p item) 312{ 313 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 314 struct tty *tp = sc->tp; 315 struct mbuf *m; 316 317 if (hook != sc->hook) 318 panic("%s", __func__); 319 320 NGI_GET_M(item, m); 321 NG_FREE_ITEM(item); 322 323 if (tp == NULL) { 324 NG_FREE_M(m); 325 return (ENXIO); 326 } 327 328 IF_LOCK(&sc->outq); 329 if (_IF_QFULL(&sc->outq)) { 330 IF_UNLOCK(&sc->outq); 331 NG_FREE_M(m); 332 return (ENOBUFS); 333 } 334 335 _IF_ENQUEUE(&sc->outq, m); 336 sc->outqlen += m->m_pkthdr.len; 337 IF_UNLOCK(&sc->outq); 338 339 /* notify the TTY that data is ready */ 340 tty_lock(tp); 341 if (!tty_gone(tp)) 342 ttydevsw_outwakeup(tp); 343 tty_unlock(tp); 344 345 return (0); 346} 347 348static size_t 349ngt_getc_inject(struct tty *tp, void *buf, size_t len) 350{ 351 sc_p sc = ttyhook_softc(tp); 352 size_t total = 0; 353 int length; 354 355 while (len) { 356 struct mbuf *m; 357 358 /* Remove first mbuf from queue */ 359 IF_DEQUEUE(&sc->outq, m); 360 if (m == NULL) 361 break; 362 363 /* Send as much of it as possible */ 364 while (m != NULL) { 365 length = min(m->m_len, len); 366 memcpy((char *)buf + total, mtod(m, char *), length); 367 368 m->m_data += length; 369 m->m_len -= length; 370 total += length; 371 len -= length; 372 373 if (m->m_len > 0) 374 break; /* device can't take any more */ 375 m = m_free(m); 376 } 377 378 /* Put remainder of mbuf chain (if any) back on queue */ 379 if (m != NULL) { 380 IF_PREPEND(&sc->outq, m); 381 break; 382 } 383 } 384 IF_LOCK(&sc->outq); 385 sc->outqlen -= total; 386 IF_UNLOCK(&sc->outq); 387 MPASS(sc->outqlen >= 0); 388 389 return (total); 390} 391 392static size_t 393ngt_getc_poll(struct tty *tp) 394{ 395 sc_p sc = ttyhook_softc(tp); 396 397 return (sc->outqlen); 398} 399 400/* 401 * Optimised TTY input. 402 * 403 * We get a buffer pointer to hopefully a complete data frame. Do not check for 404 * the hotchar, just pass it on. 405 */ 406static size_t 407ngt_rint_bypass(struct tty *tp, const void *buf, size_t len) 408{ 409 sc_p sc = ttyhook_softc(tp); 410 node_p node = sc->node; 411 struct mbuf *m, *mb; 412 size_t total = 0; 413 int error = 0, length; 414 415 tty_lock_assert(tp, MA_OWNED); 416 417 if (sc->hook == NULL) 418 return (0); 419 420 m = m_getm2(NULL, len, M_NOWAIT, MT_DATA, M_PKTHDR); 421 if (m == NULL) { 422 if (sc->flags & FLG_DEBUG) 423 log(LOG_ERR, 424 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 425 return (0); 426 } 427 m->m_pkthdr.rcvif = NULL; 428 429 for (mb = m; mb != NULL; mb = mb->m_next) { 430 length = min(M_TRAILINGSPACE(mb), len - total); 431 432 memcpy(mtod(m, char *), (const char *)buf + total, length); 433 mb->m_len = length; 434 total += length; 435 m->m_pkthdr.len += length; 436 } 437 if (sc->m != NULL) { 438 /* 439 * Odd, we have changed from non-bypass to bypass. It is 440 * unlikely but not impossible, flush the data first. 441 */ 442 sc->m->m_data = sc->m->m_pktdat; 443 NG_SEND_DATA_ONLY(error, sc->hook, sc->m); 444 sc->m = NULL; 445 } 446 NG_SEND_DATA_ONLY(error, sc->hook, m); 447 448 return (total); 449} 450 451/* 452 * Receive data coming from the device one char at a time, when it is not in 453 * bypass mode. 454 */ 455static int 456ngt_rint(struct tty *tp, char c, int flags) 457{ 458 sc_p sc = ttyhook_softc(tp); 459 node_p node = sc->node; 460 struct mbuf *m; 461 int error = 0; 462 463 tty_lock_assert(tp, MA_OWNED); 464 465 if (sc->hook == NULL) 466 return (0); 467 468 if (flags != 0) { 469 /* framing error or overrun on this char */ 470 if (sc->flags & FLG_DEBUG) 471 log(LOG_DEBUG, "%s: line error %x\n", 472 NG_NODE_NAME(node), flags); 473 return (0); 474 } 475 476 /* Get a new header mbuf if we need one */ 477 if (!(m = sc->m)) { 478 MGETHDR(m, M_NOWAIT, MT_DATA); 479 if (!m) { 480 if (sc->flags & FLG_DEBUG) 481 log(LOG_ERR, 482 "%s: can't get mbuf\n", NG_NODE_NAME(node)); 483 return (ENOBUFS); 484 } 485 m->m_len = m->m_pkthdr.len = 0; 486 m->m_pkthdr.rcvif = NULL; 487 sc->m = m; 488 } 489 490 /* Add char to mbuf */ 491 *mtod(m, u_char *) = c; 492 m->m_data++; 493 m->m_len++; 494 m->m_pkthdr.len++; 495 496 /* Ship off mbuf if it's time */ 497 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) { 498 m->m_data = m->m_pktdat; 499 sc->m = NULL; 500 NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */ 501 } 502 503 return (error); 504} 505 506static size_t 507ngt_rint_poll(struct tty *tp) 508{ 509 /* We can always accept input */ 510 return (1); 511} 512 513