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