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37 * Author: Archie Cobbs <archie@freebsd.org>
40 * $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
44 * This file implements a terminal line discipline that is also a
45 * netgraph node. Installing this line discipline on a terminal device
46 * instantiates a new netgraph node of this type, which allows access
47 * to the device via the "hook" hook of the node.
49 * Once the line discipline is installed, you can find out the name
50 * of the corresponding netgraph node via a NGIOCGINFO ioctl().
52 * Incoming characters are delievered to the hook one at a time, each
53 * in its own mbuf. You may optionally define a ``hotchar,'' which causes
54 * incoming characters to be buffered up until either the hotchar is
55 * seen or the mbuf is full (MHLEN bytes). Then all buffered characters
56 * are immediately delivered.
58 * NOTE: This node operates at spltty().
61 #include <sys/param.h>
62 #include <sys/systm.h>
63 #include <sys/kernel.h>
66 #include <sys/malloc.h>
67 #include <sys/fcntl.h>
69 #include <sys/ttycom.h>
70 #include <sys/syslog.h>
71 #include <sys/errno.h>
72 #include <sys/ioccom.h>
74 #include <netgraph/ng_message.h>
75 #include <netgraph/netgraph.h>
76 #include <netgraph/ng_tty.h>
79 #define MAX_MBUFQ 3 /* Max number of queued mbufs */
80 #define NGT_HIWATER 400 /* High water mark on output */
82 /* Per-node private info */
84 struct tty *tp; /* Terminal device */
85 node_p node; /* Netgraph node */
86 hook_p hook; /* Netgraph hook */
87 struct mbuf *m; /* Incoming data buffer */
88 struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */
89 short qlen; /* Length of queue */
90 short hotchar; /* Hotchar, or -1 if none */
91 u_int flags; /* Flags */
92 struct callout_handle chand; /* See man timeout(9) */
94 typedef struct ngt_sc *sc_p;
97 #define FLG_TIMEOUT 0x0001 /* A timeout is pending */
98 #define FLG_DEBUG 0x0002
102 #define QUEUECHECK(sc) \
107 for (k = 0, mp = &sc->qhead; \
108 k <= MAX_MBUFQ && *mp; \
109 k++, mp = &(*mp)->m_nextpkt); \
110 if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \
111 panic("%s: queue", __func__); \
114 #define QUEUECHECK(sc) do {} while (0)
117 /* Line discipline methods */
118 static int ngt_open(dev_t dev, struct tty *tp);
119 static int ngt_close(struct tty *tp, int flag);
120 static int ngt_read(struct tty *tp, struct uio *uio, int flag);
121 static int ngt_write(struct tty *tp, struct uio *uio, int flag);
122 static int ngt_tioctl(struct tty *tp,
123 u_long cmd, caddr_t data, int flag, struct thread *);
124 static int ngt_input(int c, struct tty *tp);
125 static int ngt_start(struct tty *tp);
127 /* Netgraph methods */
128 static ng_constructor_t ngt_constructor;
129 static ng_rcvmsg_t ngt_rcvmsg;
130 static ng_shutdown_t ngt_shutdown;
131 static ng_newhook_t ngt_newhook;
132 static ng_connect_t ngt_connect;
133 static ng_rcvdata_t ngt_rcvdata;
134 static ng_disconnect_t ngt_disconnect;
135 static int ngt_mod_event(module_t mod, int event, void *data);
138 static void ngt_timeout(void *arg);
140 #define ERROUT(x) do { error = (x); goto done; } while (0)
142 /* Line discipline descriptor */
143 static struct linesw ngt_disc = {
152 NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */
155 /* Netgraph node type descriptor */
156 static struct ng_type typestruct = {
170 NETGRAPH_INIT(tty, &typestruct);
173 static int ngt_nodeop_ok; /* OK to create/remove node */
174 static int ngt_ldisc;
176 /******************************************************************
177 LINE DISCIPLINE METHODS
178 ******************************************************************/
181 * Set our line discipline on the tty.
182 * Called from device open routine or ttioctl() at >= splsofttty()
185 ngt_open(dev_t dev, struct tty *tp)
187 struct thread *const td = curthread; /* XXX */
188 char name[sizeof(NG_TTY_NODE_TYPE) + 8];
192 /* Super-user only */
193 if ((error = suser(td)))
196 (void) spltty(); /* XXX is this necessary? */
198 /* Already installed? */
199 if (tp->t_line == NETGRAPHDISC) {
200 sc = (sc_p) tp->t_sc;
201 if (sc != NULL && sc->tp == tp)
205 /* Initialize private struct */
206 MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
212 sc->hotchar = NG_TTY_DFL_HOTCHAR;
213 sc->qtail = &sc->qhead;
215 callout_handle_init(&sc->chand);
217 /* Setup netgraph node */
219 error = ng_make_node_common(&typestruct, &sc->node);
222 FREE(sc, M_NETGRAPH);
225 snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
227 /* Assign node its name */
228 if ((error = ng_name_node(sc->node, name))) {
229 log(LOG_ERR, "%s: node name exists?\n", name);
231 NG_NODE_UNREF(sc->node);
236 /* Set back pointers */
237 NG_NODE_SET_PRIVATE(sc->node, sc);
238 tp->t_sc = (caddr_t) sc;
241 * Pre-allocate cblocks to the an appropriate amount.
242 * I'm not sure what is appropriate.
244 ttyflush(tp, FREAD | FWRITE);
245 clist_alloc_cblocks(&tp->t_canq, 0, 0);
246 clist_alloc_cblocks(&tp->t_rawq, 0, 0);
247 clist_alloc_cblocks(&tp->t_outq,
248 MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
257 * Line specific close routine, called from device close routine
258 * and from ttioctl at >= splsofttty(). This causes the node to
259 * be destroyed as well.
262 ngt_close(struct tty *tp, int flag)
264 const sc_p sc = (sc_p) tp->t_sc;
268 ttyflush(tp, FREAD | FWRITE);
269 clist_free_cblocks(&tp->t_outq);
272 if (sc->flags & FLG_TIMEOUT) {
273 untimeout(ngt_timeout, sc, sc->chand);
274 sc->flags &= ~FLG_TIMEOUT;
277 ng_rmnode_self(sc->node);
286 * Once the device has been turned into a node, we don't allow reading.
289 ngt_read(struct tty *tp, struct uio *uio, int flag)
295 * Once the device has been turned into a node, we don't allow writing.
298 ngt_write(struct tty *tp, struct uio *uio, int flag)
304 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
307 ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct thread *td)
309 const sc_p sc = (sc_p) tp->t_sc;
316 struct nodeinfo *const ni = (struct nodeinfo *) data;
317 const node_p node = sc->node;
319 bzero(ni, sizeof(*ni));
320 if (NG_NODE_HAS_NAME(node))
321 strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1);
322 strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1);
323 ni->id = (u_int32_t) ng_node2ID(node);
324 ni->hooks = NG_NODE_NUMHOOKS(node);
336 * Receive data coming from the device. We get one character at
337 * a time, which is kindof silly.
338 * Only guaranteed to be at splsofttty() or spltty().
341 ngt_input(int c, struct tty *tp)
343 const sc_p sc = (sc_p) tp->t_sc;
344 const node_p node = sc->node;
348 if (!sc || tp != sc->tp)
354 /* Check for error conditions */
355 if ((tp->t_state & TS_CONNECTED) == 0) {
356 if (sc->flags & FLG_DEBUG)
357 log(LOG_DEBUG, "%s: no carrier\n", NG_NODE_NAME(node));
360 if (c & TTY_ERRORMASK) {
361 /* framing error or overrun on this char */
362 if (sc->flags & FLG_DEBUG)
363 log(LOG_DEBUG, "%s: line error %x\n",
364 NG_NODE_NAME(node), c & TTY_ERRORMASK);
369 /* Get a new header mbuf if we need one */
371 MGETHDR(m, M_DONTWAIT, MT_DATA);
373 if (sc->flags & FLG_DEBUG)
375 "%s: can't get mbuf\n", NG_NODE_NAME(node));
378 m->m_len = m->m_pkthdr.len = 0;
379 m->m_pkthdr.rcvif = NULL;
383 /* Add char to mbuf */
384 *mtod(m, u_char *) = c;
389 /* Ship off mbuf if it's time */
390 if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
391 m->m_data = m->m_pktdat;
392 NG_SEND_DATA_ONLY(error, sc->hook, m);
401 * This is called when the device driver is ready for more output.
402 * Called from tty system at splsofttty() or spltty().
403 * Also call from ngt_rcv_data() when a new mbuf is available for output.
406 ngt_start(struct tty *tp)
408 const sc_p sc = (sc_p) tp->t_sc;
412 while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
413 struct mbuf *m = sc->qhead;
415 /* Remove first mbuf from queue */
418 if ((sc->qhead = m->m_nextpkt) == NULL)
419 sc->qtail = &sc->qhead;
423 /* Send as much of it as possible */
428 - b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
432 break; /* device can't take no more */
436 /* Put remainder of mbuf chain (if any) back on queue */
438 m->m_nextpkt = sc->qhead;
440 if (sc->qtail == &sc->qhead)
441 sc->qtail = &m->m_nextpkt;
448 /* Call output process whether or not there is any output. We are
449 * being called in lieu of ttstart and must do what it would. */
450 if (tp->t_oproc != NULL)
453 /* This timeout is needed for operation on a pseudo-tty, because the
454 * pty code doesn't call pppstart after it has drained the t_outq. */
455 if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
456 sc->chand = timeout(ngt_timeout, sc, 1);
457 sc->flags |= FLG_TIMEOUT;
464 * We still have data to output to the device, so try sending more.
467 ngt_timeout(void *arg)
469 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 node)
495 * Add a new hook. There can only be one.
498 ngt_newhook(node_p node, hook_p hook, const char *name)
500 const sc_p sc = NG_NODE_PRIVATE(node);
503 if (strcmp(name, NG_TTY_HOOK))
515 * Set the hooks into queueing mode (for outgoing packets)
516 * Force single client at a time.
519 ngt_connect(hook_p hook)
521 /*NG_HOOK_FORCE_WRITER(hook);
522 NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));*/
527 * Disconnect the hook
530 ngt_disconnect(hook_p hook)
532 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
536 if (hook != sc->hook)
546 * Remove this node. The does the netgraph portion of the shutdown.
547 * This should only be called indirectly from ngt_close().
550 ngt_shutdown(node_p node)
552 const sc_p sc = NG_NODE_PRIVATE(node);
556 NG_NODE_SET_PRIVATE(node, NULL);
557 NG_NODE_UNREF(sc->node);
560 bzero(sc, sizeof(*sc));
561 FREE(sc, M_NETGRAPH);
566 * Receive incoming data from netgraph system. Put it on our
567 * output queue and start output if necessary.
570 ngt_rcvdata(hook_p hook, item_p item)
572 const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
576 if (hook != sc->hook)
582 if (sc->qlen >= MAX_MBUFQ)
586 sc->qtail = &m->m_nextpkt;
600 * Receive control message
603 ngt_rcvmsg(node_p node, item_p item, hook_p lasthook)
605 const sc_p sc = NG_NODE_PRIVATE(node);
606 struct ng_mesg *resp = NULL;
610 NGI_GET_MSG(item, msg);
611 switch (msg->header.typecookie) {
613 switch (msg->header.cmd) {
614 case NGM_TTY_SET_HOTCHAR:
618 if (msg->header.arglen != sizeof(int))
620 hotchar = *((int *) msg->data);
621 if (hotchar != (u_char) hotchar && hotchar != -1)
623 sc->hotchar = hotchar; /* race condition is OK */
626 case NGM_TTY_GET_HOTCHAR:
627 NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
630 /* Race condition here is OK */
631 *((int *) resp->data) = sc->hotchar;
641 NG_RESPOND_MSG(error, node, item, resp);
646 /******************************************************************
648 ******************************************************************/
651 * Handle loading and unloading for this node type
654 ngt_mod_event(module_t mod, int event, void *data)
656 /* struct ng_type *const type = data;*/
662 /* Register line discipline */
664 if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
666 log(LOG_ERR, "%s: can't register line discipline",
675 /* Unregister line discipline */
677 ldisc_deregister(ngt_ldisc);