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38 * Author: Archie Cobbs <archie@freebsd.org>
40 * $FreeBSD: src/sys/netgraph/ng_tty.c,v 1.7.2.3 2002/02/13 00:43:12 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>
69 #include <sys/malloc.h>
70 #include <sys/fcntl.h>
72 #include <sys/ttycom.h>
73 #include <sys/syslog.h>
74 #include <sys/errno.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
= priv_check(td
, PRIV_ROOT
)))
199 lwkt_gettoken(&tty_token
);
201 /* Already installed? */
202 if (tp
->t_line
== NETGRAPHDISC
) {
203 sc
= (sc_p
) tp
->t_sc
;
204 if (sc
!= NULL
&& sc
->tp
== tp
)
208 /* Initialize private struct */
209 sc
= kmalloc(sizeof(*sc
), M_NETGRAPH
, M_WAITOK
| M_ZERO
);
211 sc
->hotchar
= NG_TTY_DFL_HOTCHAR
;
212 sc
->qtail
= &sc
->qhead
;
214 callout_init_mp(&sc
->ctimeout
);
216 /* Setup netgraph node */
218 error
= ng_make_node_common(&typestruct
, &sc
->node
);
221 kfree(sc
, M_NETGRAPH
);
224 ksnprintf(name
, sizeof(name
), "%s%d", typestruct
.name
, ngt_unit
++);
226 /* Set back pointers */
227 sc
->node
->private = sc
;
228 tp
->t_sc
= (caddr_t
) sc
;
230 /* Assign node its name */
231 if ((error
= ng_name_node(sc
->node
, name
))) {
232 log(LOG_ERR
, "%s: node name exists?\n", name
);
240 * Pre-allocate cblocks to the an appropriate amount.
241 * I'm not sure what is appropriate.
243 ttyflush(tp
, FREAD
| FWRITE
);
244 clist_alloc_cblocks(&tp
->t_canq
, 0, 0);
245 clist_alloc_cblocks(&tp
->t_rawq
, 0, 0);
246 clist_alloc_cblocks(&tp
->t_outq
,
247 MLEN
+ NGT_HIWATER
, MLEN
+ NGT_HIWATER
);
251 lwkt_reltoken(&tty_token
);
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
;
267 lwkt_gettoken(&tty_token
);
268 ttyflush(tp
, FREAD
| FWRITE
);
269 clist_free_cblocks(&tp
->t_outq
);
272 if (sc
->flags
& FLG_TIMEOUT
) {
273 callout_stop(&sc
->ctimeout
);
274 sc
->flags
&= ~FLG_TIMEOUT
;
281 lwkt_reltoken(&tty_token
);
287 * Once the device has been turned into a node, we don't allow reading.
290 ngt_read(struct tty
*tp
, struct uio
*uio
, int flag
)
296 * Once the device has been turned into a node, we don't allow writing.
299 ngt_write(struct tty
*tp
, struct uio
*uio
, int flag
)
305 * We implement the NGIOCGINFO ioctl() defined in ng_message.h.
308 ngt_tioctl(struct tty
*tp
, u_long cmd
, caddr_t data
, int flag
, struct ucred
*cred
)
310 const sc_p sc
= (sc_p
) tp
->t_sc
;
314 lwkt_gettoken(&tty_token
);
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
)(uintptr_t)node
;
326 ni
->hooks
= node
->numhooks
;
333 lwkt_reltoken(&tty_token
);
339 * Receive data coming from the device. We get one character at
340 * a time, which is kindof silly.
341 * Only guaranteed to be at splsofttty() or spltty().
344 ngt_input(int c
, struct tty
*tp
)
346 const sc_p sc
= (sc_p
) tp
->t_sc
;
347 const node_p node
= sc
? sc
->node
: NULL
;
351 lwkt_gettoken(&tty_token
);
352 if (!sc
|| tp
!= sc
->tp
) {
353 lwkt_reltoken(&tty_token
);
360 /* Check for error conditions */
361 if ((tp
->t_state
& TS_CONNECTED
) == 0) {
362 if (sc
->flags
& FLG_DEBUG
)
363 log(LOG_DEBUG
, "%s: no carrier\n", node
->name
);
366 if (c
& TTY_ERRORMASK
) {
367 /* framing error or overrun on this char */
368 if (sc
->flags
& FLG_DEBUG
)
369 log(LOG_DEBUG
, "%s: line error %x\n",
370 node
->name
, c
& TTY_ERRORMASK
);
375 /* Get a new header mbuf if we need one */
377 MGETHDR(m
, M_NOWAIT
, MT_DATA
);
379 if (sc
->flags
& FLG_DEBUG
)
381 "%s: can't get mbuf\n", node
->name
);
384 m
->m_len
= m
->m_pkthdr
.len
= 0;
385 m
->m_pkthdr
.rcvif
= NULL
;
389 /* Add char to mbuf */
390 *mtod(m
, u_char
*) = c
;
395 /* Ship off mbuf if it's time */
396 if (sc
->hotchar
== -1 || c
== sc
->hotchar
|| m
->m_len
>= MHLEN
) {
397 m
->m_data
= m
->m_pktdat
;
398 error
= ng_queue_data(sc
->hook
, m
, NULL
);
403 lwkt_reltoken(&tty_token
);
408 * This is called when the device driver is ready for more output.
409 * Called from tty system at splsofttty() or spltty().
410 * Also call from ngt_rcv_data() when a new mbuf is available for output.
413 ngt_start(struct tty
*tp
)
415 const sc_p sc
= (sc_p
) tp
->t_sc
;
418 lwkt_gettoken(&tty_token
);
419 while (tp
->t_outq
.c_cc
< NGT_HIWATER
) { /* XXX 2.2 specific ? */
420 struct mbuf
*m
= sc
->qhead
;
422 /* Remove first mbuf from queue */
425 if ((sc
->qhead
= m
->m_nextpkt
) == NULL
)
426 sc
->qtail
= &sc
->qhead
;
430 /* Send as much of it as possible */
435 - b_to_q(mtod(m
, u_char
*), m
->m_len
, &tp
->t_outq
);
439 break; /* device can't take no more */
443 /* Put remainder of mbuf chain (if any) back on queue */
445 m
->m_nextpkt
= sc
->qhead
;
447 if (sc
->qtail
== &sc
->qhead
)
448 sc
->qtail
= &m
->m_nextpkt
;
455 /* Call output process whether or not there is any output. We are
456 * being called in lieu of ttstart and must do what it would. */
457 if (tp
->t_oproc
!= NULL
)
460 /* This timeout is needed for operation on a pseudo-tty, because the
461 * pty code doesn't call pppstart after it has drained the t_outq. */
462 if (sc
->qhead
&& (sc
->flags
& FLG_TIMEOUT
) == 0) {
463 callout_reset(&sc
->ctimeout
, 1, ngt_timeout
, sc
);
464 sc
->flags
|= FLG_TIMEOUT
;
466 lwkt_reltoken(&tty_token
);
472 * We still have data to output to the device, so try sending more.
475 ngt_timeout(void *arg
)
477 const sc_p sc
= (sc_p
) arg
;
480 lwkt_gettoken(&tty_token
);
481 sc
->flags
&= ~FLG_TIMEOUT
;
483 lwkt_reltoken(&tty_token
);
487 /******************************************************************
488 NETGRAPH NODE METHODS
489 ******************************************************************/
492 * Initialize a new node of this type.
494 * We only allow nodes to be created as a result of setting
495 * the line discipline on a tty, so always return an error if not.
498 ngt_constructor(node_p
*nodep
)
502 return (ng_make_node_common(&typestruct
, nodep
));
506 * Add a new hook. There can only be one.
509 ngt_newhook(node_p node
, hook_p hook
, const char *name
)
511 const sc_p sc
= node
->private;
514 if (strcmp(name
, NG_TTY_HOOK
))
517 lwkt_gettoken(&tty_token
);
522 lwkt_reltoken(&tty_token
);
528 * Disconnect the hook
531 ngt_disconnect(hook_p hook
)
533 const sc_p sc
= hook
->node
->private;
536 lwkt_gettoken(&tty_token
);
537 if (hook
!= sc
->hook
)
542 lwkt_reltoken(&tty_token
);
548 * Remove this node. The does the netgraph portion of the shutdown.
549 * This should only be called indirectly from ngt_close().
552 ngt_shutdown(node_p node
)
554 const sc_p sc
= node
->private;
558 lwkt_gettoken(&tty_token
);
561 node
->private = NULL
;
565 bzero(sc
, sizeof(*sc
));
566 kfree(sc
, M_NETGRAPH
);
567 lwkt_reltoken(&tty_token
);
572 * Receive incoming data from netgraph system. Put it on our
573 * output queue and start output if necessary.
576 ngt_rcvdata(hook_p hook
, struct mbuf
*m
, meta_p meta
)
578 const sc_p sc
= hook
->node
->private;
581 if (hook
!= sc
->hook
)
585 lwkt_gettoken(&tty_token
);
586 if (sc
->qlen
>= MAX_MBUFQ
)
590 sc
->qtail
= &m
->m_nextpkt
;
597 lwkt_reltoken(&tty_token
);
605 * Receive control message
608 ngt_rcvmsg(node_p node
, struct ng_mesg
*msg
, const char *retaddr
,
609 struct ng_mesg
**rptr
)
611 const sc_p sc
= (sc_p
) node
->private;
612 struct ng_mesg
*resp
= NULL
;
615 lwkt_gettoken(&tty_token
);
616 switch (msg
->header
.typecookie
) {
618 switch (msg
->header
.cmd
) {
619 case NGM_TTY_SET_HOTCHAR
:
623 if (msg
->header
.arglen
!= sizeof(int))
625 hotchar
= *((int *) msg
->data
);
626 if (hotchar
!= (u_char
) hotchar
&& hotchar
!= -1)
628 sc
->hotchar
= hotchar
; /* race condition is OK */
631 case NGM_TTY_GET_HOTCHAR
:
632 NG_MKRESPONSE(resp
, msg
, sizeof(int), M_NOWAIT
);
635 /* Race condition here is OK */
636 *((int *) resp
->data
) = sc
->hotchar
;
648 kfree(resp
, M_NETGRAPH
);
651 kfree(msg
, M_NETGRAPH
);
652 lwkt_reltoken(&tty_token
);
656 /******************************************************************
658 ******************************************************************/
661 * Handle loading and unloading for this node type
664 ngt_mod_event(module_t mod
, int event
, void *data
)
666 /* struct ng_type *const type = data;*/
671 /* Register line discipline */
673 if ((ngt_ldisc
= ldisc_register(NETGRAPHDISC
, &ngt_disc
)) < 0) {
675 log(LOG_ERR
, "%s: can't register line discipline",
684 /* Unregister line discipline */
686 ldisc_deregister(ngt_ldisc
);