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37 * Author: Archie Cobbs <archie@freebsd.org>
39 * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 dillon Exp $
40 * $DragonFly: src/sys/netgraph/tty/ng_tty.c,v 1.17 2006/12/20 18:14:43 dillon Exp $
41 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
45 * This file implements a terminal line discipline that is also a
46 * netgraph node. Installing this line discipline on a terminal device
47 * instantiates a new netgraph node of this type, which allows access
48 * to the device via the "hook" hook of the node.
50 * Once the line discipline is installed, you can find out the name
51 * of the corresponding netgraph node via a NGIOCGINFO ioctl().
53 * Incoming characters are delievered to the hook one at a time, each
54 * in its own mbuf. You may optionally define a ``hotchar,'' which causes
55 * incoming characters to be buffered up until either the hotchar is
56 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters
57 * are immediately delivered.
59 * NOTE: This node operates at spltty().
62 #include <sys/param.h>
63 #include <sys/systm.h>
64 #include <sys/kernel.h>
68 #include <sys/malloc.h>
69 #include <sys/fcntl.h>
71 #include <sys/ttycom.h>
72 #include <sys/syslog.h>
73 #include <sys/errno.h>
74 #include <sys/ioccom.h>
75 #include <sys/thread2.h>
77 #include <netgraph/ng_message.h>
78 #include <netgraph/netgraph.h>
82 #define MAX_MBUFQ 3 /* Max number of queued mbufs */
83 #define NGT_HIWATER 400 /* High water mark on output */
85 /* Per-node private info */
87 struct tty *tp; /* Terminal device */
88 node_p node; /* Netgraph node */
89 hook_p hook; /* Netgraph hook */
90 struct mbuf *m; /* Incoming data buffer */
91 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */
92 short qlen; /* Length of queue */
93 short hotchar; /* Hotchar, or -1 if none */
94 u_int flags; /* Flags */
95 struct callout ctimeout; /* See man timeout(9) */
97 typedef struct ngt_sc *sc_p;
100 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */
101 #define FLG_DEBUG 0x0002
105 #define QUEUECHECK(sc) \
110 for (k = 0, mp = &sc->qhead; \
111 k <= MAX_MBUFQ && *mp; \
112 k++, mp = &(*mp)->m_nextpkt); \
113 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \
114 panic("%s: queue", __func__); \
117 #define QUEUECHECK(sc) do {} while (0)
120 /* Line discipline methods */
121 static int ngt_open(cdev_t dev, struct tty *tp);
122 static int ngt_close(struct tty *tp, int flag);
123 static int ngt_read(struct tty *tp, struct uio *uio, int flag);
124 static int ngt_write(struct tty *tp, struct uio *uio, int flag);
125 static int ngt_tioctl(struct tty *tp,
126 u_long cmd, caddr_t data, int flag, struct ucred *cred);
127 static int ngt_input(int c, struct tty *tp);
128 static int ngt_start(struct tty *tp);
130 /* Netgraph methods */
131 static ng_constructor_t ngt_constructor;
132 static ng_rcvmsg_t ngt_rcvmsg;
133 static ng_shutdown_t ngt_shutdown;
134 static ng_newhook_t ngt_newhook;
135 static ng_rcvdata_t ngt_rcvdata;
136 static ng_disconnect_t ngt_disconnect;
137 static int ngt_mod_event(module_t mod, int event, void *data);
140 static void ngt_timeout(void *arg);
142 #define ERROUT(x) do { error = (x); goto done; } while (0)
144 /* Line discipline descriptor */
145 static struct linesw ngt_disc = {
154 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */
157 /* Netgraph node type descriptor */
158 static struct ng_type typestruct = {
173 NETGRAPH_INIT(tty, &typestruct);
176 static int ngt_nodeop_ok; /* OK to create/remove node */
177 static int ngt_ldisc;
179 /******************************************************************
180 LINE DISCIPLINE METHODS
181 ******************************************************************/
184 * Set our line discipline on the tty.
185 * Called from device open routine or ttioctl() at >= splsofttty()
188 ngt_open(cdev_t dev, struct tty *tp)
190 struct thread *td = curthread; /* XXX */
191 char name[sizeof(NG_TTY_NODE_TYPE) + 8];
195 /* Super-user only */
196 if ((error = suser(td)))
200 /* Already installed? */
201 if (tp->t_line == NETGRAPHDISC) {
202 sc = (sc_p) tp->t_sc;
203 if (sc != NULL && sc->tp == tp)
207 /* Initialize private struct */
208 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK);
213 bzero(sc, sizeof(*sc));
215 sc->hotchar = NG_TTY_DFL_HOTCHAR;
216 sc->qtail = &sc->qhead;
218 callout_init(&sc->ctimeout);
220 /* Setup netgraph node */
222 error = ng_make_node_common(&typestruct, &sc->node);
225 FREE(sc, M_NETGRAPH);
228 ksnprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
230 /* Set back pointers */
231 sc->node->private = sc;
232 tp->t_sc = (caddr_t) sc;
234 /* Assign node its name */
235 if ((error = ng_name_node(sc->node, name))) {
236 log(LOG_ERR, "%s: node name exists?\n", name);
244 * Pre-allocate cblocks to the an appropriate amount.
245 * I'm not sure what is appropriate.
247 ttyflush(tp, FREAD | FWRITE);
248 clist_alloc_cblocks(&tp->t_canq, 0, 0);
249 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
250 clist_alloc_cblocks(&tp->t_outq,
251 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
260 * Line specific close routine, called from device close routine
261 * and from ttioctl at >= splsofttty(). This causes the node to
262 * be destroyed as well.
265 ngt_close(struct tty *tp, int flag)
267 const sc_p sc = (sc_p) tp->t_sc;
270 ttyflush(tp, FREAD | FWRITE);
271 clist_free_cblocks(&tp->t_outq);
274 if (sc->flags & FLG_TIMEOUT) {
275 callout_stop(&sc->ctimeout);
276 sc->flags &= ~FLG_TIMEOUT;
288 * Once the device has been turned into a node, we don't allow reading.
291 ngt_read(struct tty *tp, struct uio *uio, int flag)
297 * Once the device has been turned into a node, we don't allow writing.
300 ngt_write(struct tty *tp, struct uio *uio, int flag)
306 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
309 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct ucred *cred)
311 const sc_p sc = (sc_p) tp->t_sc;
318 struct nodeinfo *const ni = (struct nodeinfo *) data;
319 const node_p node = sc->node;
321 bzero(ni, sizeof(*ni));
323 strncpy(ni->name, node->name, sizeof(ni->name) - 1);
324 strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
325 ni->id = (u_int32_t) node;
326 ni->hooks = node->numhooks;
338 * Receive data coming from the device. We get one character at
339 * a time, which is kindof silly.
340 * Only guaranteed to be at splsofttty() or spltty().
343 ngt_input(int c, struct tty *tp)
345 const sc_p sc = (sc_p) tp->t_sc;
346 const node_p node = sc->node;
350 if (!sc || tp != sc->tp)
356 /* Check for error conditions */
357 if ((tp->t_state & TS_CONNECTED) == 0) {
358 if (sc->flags & FLG_DEBUG)
359 log(LOG_DEBUG, "%s: no carrier\n", node->name);
362 if (c & TTY_ERRORMASK) {
363 /* framing error or overrun on this char */
364 if (sc->flags & FLG_DEBUG)
365 log(LOG_DEBUG, "%s: line error %x\n",
366 node->name, c & TTY_ERRORMASK);
371 /* Get a new header mbuf if we need one */
373 MGETHDR(m, MB_DONTWAIT, MT_DATA);
375 if (sc->flags & FLG_DEBUG)
377 "%s: can't get mbuf\n", node->name);
380 m->m_len = m->m_pkthdr.len = 0;
381 m->m_pkthdr.rcvif = NULL;
385 /* Add char to mbuf */
386 *mtod(m, u_char *) = c;
391 /* Ship off mbuf if it's time */
392 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
393 m->m_data = m->m_pktdat;
394 error = ng_queue_data(sc->hook, m, NULL);
403 * This is called when the device driver is ready for more output.
404 * Called from tty system at splsofttty() or spltty().
405 * Also call from ngt_rcv_data() when a new mbuf is available for output.
408 ngt_start(struct tty *tp)
410 const sc_p sc = (sc_p) tp->t_sc;
413 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
414 struct mbuf *m = sc->qhead;
416 /* Remove first mbuf from queue */
419 if ((sc->qhead = m->m_nextpkt) == NULL)
420 sc->qtail = &sc->qhead;
424 /* Send as much of it as possible */
429 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
433 break; /* device can't take no more */
437 /* Put remainder of mbuf chain (if any) back on queue */
439 m->m_nextpkt = sc->qhead;
441 if (sc->qtail == &sc->qhead)
442 sc->qtail = &m->m_nextpkt;
449 /* Call output process whether or not there is any output. We are
450 * being called in lieu of ttstart and must do what it would. */
451 if (tp->t_oproc != NULL)
454 /* This timeout is needed for operation on a pseudo-tty, because the
455 * pty code doesn't call pppstart after it has drained the t_outq. */
456 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
457 callout_reset(&sc->ctimeout, 1, ngt_timeout, sc);
458 sc->flags |= FLG_TIMEOUT;
465 * We still have data to output to the device, so try sending more.
468 ngt_timeout(void *arg)
470 const sc_p sc = (sc_p) arg;
473 sc->flags &= ~FLG_TIMEOUT;
478 /******************************************************************
479 NETGRAPH NODE METHODS
480 ******************************************************************/
483 * Initialize a new node of this type.
485 * We only allow nodes to be created as a result of setting
486 * the line discipline on a tty, so always return an error if not.
489 ngt_constructor(node_p *nodep)
493 return (ng_make_node_common(&typestruct, nodep));
497 * Add a new hook. There can only be one.
500 ngt_newhook(node_p node, hook_p hook, const char *name)
502 const sc_p sc = node->private;
505 if (strcmp(name, NG_TTY_HOOK))
517 * Disconnect the hook
520 ngt_disconnect(hook_p hook)
522 const sc_p sc = hook->node->private;
525 if (hook != sc->hook)
535 * Remove this node. The does the netgraph portion of the shutdown.
536 * This should only be called indirectly from ngt_close().
539 ngt_shutdown(node_p node)
541 const sc_p sc = node->private;
547 node->private = NULL;
551 bzero(sc, sizeof(*sc));
552 FREE(sc, M_NETGRAPH);
557 * Receive incoming data from netgraph system. Put it on our
558 * output queue and start output if necessary.
561 ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
563 const sc_p sc = hook->node->private;
566 if (hook != sc->hook)
570 if (sc->qlen >= MAX_MBUFQ)
574 sc->qtail = &m->m_nextpkt;
588 * Receive control message
591 ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
592 struct ng_mesg **rptr)
594 const sc_p sc = (sc_p) node->private;
595 struct ng_mesg *resp = NULL;
598 switch (msg->header.typecookie) {
600 switch (msg->header.cmd) {
601 case NGM_TTY_SET_HOTCHAR:
605 if (msg->header.arglen != sizeof(int))
607 hotchar = *((int *) msg->data);
608 if (hotchar != (u_char) hotchar && hotchar != -1)
610 sc->hotchar = hotchar; /* race condition is OK */
613 case NGM_TTY_GET_HOTCHAR:
614 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
617 /* Race condition here is OK */
618 *((int *) resp->data) = sc->hotchar;
630 FREE(resp, M_NETGRAPH);
633 FREE(msg, M_NETGRAPH);
637 /******************************************************************
639 ******************************************************************/
642 * Handle loading and unloading for this node type
645 ngt_mod_event(module_t mod, int event, void *data)
647 /* struct ng_type *const type = data;*/
652 /* Register line discipline */
654 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
656 log(LOG_ERR, "%s: can't register line discipline",
665 /* Unregister line discipline */
667 ldisc_deregister(ngt_ldisc);