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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
);