FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_tty.c
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: releng/10.3/sys/netgraph/ng_tty.c 243882 2012-12-05 08:04:20Z 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 */
86 struct 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 };
96 typedef struct ngt_softc *sc_p;
97
98 /* Flags */
99 #define FLG_DEBUG 0x0002
100
101 /* Netgraph methods */
102 static ng_constructor_t ngt_constructor;
103 static ng_rcvmsg_t ngt_rcvmsg;
104 static ng_shutdown_t ngt_shutdown;
105 static ng_newhook_t ngt_newhook;
106 static ng_connect_t ngt_connect;
107 static ng_rcvdata_t ngt_rcvdata;
108 static ng_disconnect_t ngt_disconnect;
109
110 #define ERROUT(x) do { error = (x); goto done; } while (0)
111
112 static th_getc_inject_t ngt_getc_inject;
113 static th_getc_poll_t ngt_getc_poll;
114 static th_rint_t ngt_rint;
115 static th_rint_bypass_t ngt_rint_bypass;
116 static th_rint_poll_t ngt_rint_poll;
117
118 static 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 */
127 static 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 };
138 NETGRAPH_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 */
153 static int
154 ngt_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 */
173 static int
174 ngt_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 */
196 static int
197 ngt_connect(hook_p hook)
198 {
199 NG_HOOK_FORCE_QUEUE(hook);
200 return (0);
201 }
202
203 /*
204 * Disconnect the hook
205 */
206 static int
207 ngt_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 */
224 static int
225 ngt_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 */
247 static int
248 ngt_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 }
300 done:
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 */
310 static int
311 ngt_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_DROP(&sc->outq);
331 IF_UNLOCK(&sc->outq);
332 NG_FREE_M(m);
333 return (ENOBUFS);
334 }
335
336 _IF_ENQUEUE(&sc->outq, m);
337 sc->outqlen += m->m_pkthdr.len;
338 IF_UNLOCK(&sc->outq);
339
340 /* notify the TTY that data is ready */
341 tty_lock(tp);
342 if (!tty_gone(tp))
343 ttydevsw_outwakeup(tp);
344 tty_unlock(tp);
345
346 return (0);
347 }
348
349 static size_t
350 ngt_getc_inject(struct tty *tp, void *buf, size_t len)
351 {
352 sc_p sc = ttyhook_softc(tp);
353 size_t total = 0;
354 int length;
355
356 while (len) {
357 struct mbuf *m;
358
359 /* Remove first mbuf from queue */
360 IF_DEQUEUE(&sc->outq, m);
361 if (m == NULL)
362 break;
363
364 /* Send as much of it as possible */
365 while (m != NULL) {
366 length = min(m->m_len, len);
367 memcpy((char *)buf + total, mtod(m, char *), length);
368
369 m->m_data += length;
370 m->m_len -= length;
371 total += length;
372 len -= length;
373
374 if (m->m_len > 0)
375 break; /* device can't take any more */
376 m = m_free(m);
377 }
378
379 /* Put remainder of mbuf chain (if any) back on queue */
380 if (m != NULL) {
381 IF_PREPEND(&sc->outq, m);
382 break;
383 }
384 }
385 IF_LOCK(&sc->outq);
386 sc->outqlen -= total;
387 IF_UNLOCK(&sc->outq);
388 MPASS(sc->outqlen >= 0);
389
390 return (total);
391 }
392
393 static size_t
394 ngt_getc_poll(struct tty *tp)
395 {
396 sc_p sc = ttyhook_softc(tp);
397
398 return (sc->outqlen);
399 }
400
401 /*
402 * Optimised TTY input.
403 *
404 * We get a buffer pointer to hopefully a complete data frame. Do not check for
405 * the hotchar, just pass it on.
406 */
407 static size_t
408 ngt_rint_bypass(struct tty *tp, const void *buf, size_t len)
409 {
410 sc_p sc = ttyhook_softc(tp);
411 node_p node = sc->node;
412 struct mbuf *m, *mb;
413 size_t total = 0;
414 int error = 0, length;
415
416 tty_lock_assert(tp, MA_OWNED);
417
418 if (sc->hook == NULL)
419 return (0);
420
421 m = m_getm2(NULL, len, M_NOWAIT, MT_DATA, M_PKTHDR);
422 if (m == NULL) {
423 if (sc->flags & FLG_DEBUG)
424 log(LOG_ERR,
425 "%s: can't get mbuf\n", NG_NODE_NAME(node));
426 return (0);
427 }
428 m->m_pkthdr.rcvif = NULL;
429
430 for (mb = m; mb != NULL; mb = mb->m_next) {
431 length = min(M_TRAILINGSPACE(mb), len - total);
432
433 memcpy(mtod(m, char *), (const char *)buf + total, length);
434 mb->m_len = length;
435 total += length;
436 m->m_pkthdr.len += length;
437 }
438 if (sc->m != NULL) {
439 /*
440 * Odd, we have changed from non-bypass to bypass. It is
441 * unlikely but not impossible, flush the data first.
442 */
443 sc->m->m_data = sc->m->m_pktdat;
444 NG_SEND_DATA_ONLY(error, sc->hook, sc->m);
445 sc->m = NULL;
446 }
447 NG_SEND_DATA_ONLY(error, sc->hook, m);
448
449 return (total);
450 }
451
452 /*
453 * Receive data coming from the device one char at a time, when it is not in
454 * bypass mode.
455 */
456 static int
457 ngt_rint(struct tty *tp, char c, int flags)
458 {
459 sc_p sc = ttyhook_softc(tp);
460 node_p node = sc->node;
461 struct mbuf *m;
462 int error = 0;
463
464 tty_lock_assert(tp, MA_OWNED);
465
466 if (sc->hook == NULL)
467 return (0);
468
469 if (flags != 0) {
470 /* framing error or overrun on this char */
471 if (sc->flags & FLG_DEBUG)
472 log(LOG_DEBUG, "%s: line error %x\n",
473 NG_NODE_NAME(node), flags);
474 return (0);
475 }
476
477 /* Get a new header mbuf if we need one */
478 if (!(m = sc->m)) {
479 MGETHDR(m, M_NOWAIT, MT_DATA);
480 if (!m) {
481 if (sc->flags & FLG_DEBUG)
482 log(LOG_ERR,
483 "%s: can't get mbuf\n", NG_NODE_NAME(node));
484 return (ENOBUFS);
485 }
486 m->m_len = m->m_pkthdr.len = 0;
487 m->m_pkthdr.rcvif = NULL;
488 sc->m = m;
489 }
490
491 /* Add char to mbuf */
492 *mtod(m, u_char *) = c;
493 m->m_data++;
494 m->m_len++;
495 m->m_pkthdr.len++;
496
497 /* Ship off mbuf if it's time */
498 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
499 m->m_data = m->m_pktdat;
500 sc->m = NULL;
501 NG_SEND_DATA_ONLY(error, sc->hook, m); /* Will queue */
502 }
503
504 return (error);
505 }
506
507 static size_t
508 ngt_rint_poll(struct tty *tp)
509 {
510 /* We can always accept input */
511 return (1);
512 }
513
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