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 * $FreeBSD$
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_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, ifqmaxlen);
168
169 return (0);
170 }
171
172 /*
173 * Add a new hook. There can only be one.
174 */
175 static int
176 ngt_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 */
198 static int
199 ngt_connect(hook_p hook)
200 {
201 NG_HOOK_FORCE_QUEUE(hook);
202 return (0);
203 }
204
205 /*
206 * Disconnect the hook
207 */
208 static int
209 ngt_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 */
226 static int
227 ngt_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 */
249 static int
250 ngt_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 }
302 done:
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 */
312 static int
313 ngt_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
351 static size_t
352 ngt_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
395 static size_t
396 ngt_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 */
409 static size_t
410 ngt_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 */
458 static int
459 ngt_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
509 static size_t
510 ngt_rint_poll(struct tty *tp)
511 {
512 /* We can always accept input */
513 return (1);
514 }
515
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