freebsd-dev/sys/netgraph/ng_tty.c
Julian Elischer 589f6ed8ce Divorce the kernel binary ABI version number from the message
format version number. (userland programs should not need to be
recompiled when the netgraph kernel internal ABI is changed.

Also fix modules that don;t handle the fact that a caller may not supply
a return message pointer. (benign at the moment because the calling code
checks, but that will change)
2000-12-18 20:03:32 +00:00

698 lines
16 KiB
C

/*
* ng_tty.c
*
* Copyright (c) 1996-1999 Whistle Communications, Inc.
* All rights reserved.
*
* Subject to the following obligations and disclaimer of warranty, use and
* redistribution of this software, in source or object code forms, with or
* without modifications are expressly permitted by Whistle Communications;
* provided, however, that:
* 1. Any and all reproductions of the source or object code must include the
* copyright notice above and the following disclaimer of warranties; and
* 2. No rights are granted, in any manner or form, to use Whistle
* Communications, Inc. trademarks, including the mark "WHISTLE
* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
* such appears in the above copyright notice or in the software.
*
* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* Author: Archie Cobbs <archie@freebsd.org>
*
* $FreeBSD$
* $Whistle: ng_tty.c,v 1.21 1999/11/01 09:24:52 julian Exp $
*/
/*
* This file implements a terminal line discipline that is also a
* netgraph node. Installing this line discipline on a terminal device
* instantiates a new netgraph node of this type, which allows access
* to the device via the "hook" hook of the node.
*
* Once the line discipline is installed, you can find out the name
* of the corresponding netgraph node via a NGIOCGINFO ioctl().
*
* Incoming characters are delievered to the hook one at a time, each
* in its own mbuf. You may optionally define a ``hotchar,'' which causes
* incoming characters to be buffered up until either the hotchar is
* seen or the mbuf is full (MHLEN bytes). Then all buffered characters
* are immediately delivered.
*
* NOTE: This node operates at spltty().
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <sys/tty.h>
#include <sys/ttycom.h>
#include <sys/syslog.h>
#include <sys/errno.h>
#include <sys/ioccom.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_tty.h>
#ifdef __i386__ /* fiddle with the spl locking */
#include <sys/bus.h>
#include <machine/ipl.h>
#endif
/* Misc defs */
#define MAX_MBUFQ 3 /* Max number of queued mbufs */
#define NGT_HIWATER 400 /* High water mark on output */
/* Per-node private info */
struct ngt_sc {
struct tty *tp; /* Terminal device */
node_p node; /* Netgraph node */
hook_p hook; /* Netgraph hook */
struct mbuf *m; /* Incoming data buffer */
struct mbuf *qhead, **qtail; /* Queue of outgoing mbuf's */
short qlen; /* Length of queue */
short hotchar; /* Hotchar, or -1 if none */
u_int flags; /* Flags */
struct callout_handle chand; /* See man timeout(9) */
};
typedef struct ngt_sc *sc_p;
/* Flags */
#define FLG_TIMEOUT 0x0001 /* A timeout is pending */
#define FLG_DEBUG 0x0002
/* Debugging */
#ifdef INVARIANTS
#define QUEUECHECK(sc) \
do { \
struct mbuf **mp; \
int k; \
\
for (k = 0, mp = &sc->qhead; \
k <= MAX_MBUFQ && *mp; \
k++, mp = &(*mp)->m_nextpkt); \
if (k != sc->qlen || k > MAX_MBUFQ || *mp || mp != sc->qtail) \
panic(__FUNCTION__ ": queue"); \
} while (0)
#else
#define QUEUECHECK(sc) do {} while (0)
#endif
/* Line discipline methods */
static int ngt_open(dev_t dev, struct tty *tp);
static int ngt_close(struct tty *tp, int flag);
static int ngt_read(struct tty *tp, struct uio *uio, int flag);
static int ngt_write(struct tty *tp, struct uio *uio, int flag);
static int ngt_tioctl(struct tty *tp,
u_long cmd, caddr_t data, int flag, struct proc *);
static int ngt_input(int c, struct tty *tp);
static int ngt_start(struct tty *tp);
/* Netgraph methods */
static ng_constructor_t ngt_constructor;
static ng_rcvmsg_t ngt_rcvmsg;
static ng_shutdown_t ngt_shutdown;
static ng_newhook_t ngt_newhook;
static ng_connect_t ngt_connect;
static ng_rcvdata_t ngt_rcvdata;
static ng_disconnect_t ngt_disconnect;
static int ngt_mod_event(module_t mod, int event, void *data);
/* Other stuff */
static void ngt_timeout(void *arg);
#define ERROUT(x) do { error = (x); goto done; } while (0)
/* Line discipline descriptor */
static struct linesw ngt_disc = {
ngt_open,
ngt_close,
ngt_read,
ngt_write,
ngt_tioctl,
ngt_input,
ngt_start,
ttymodem,
NG_TTY_DFL_HOTCHAR /* XXX can't change this in serial driver */
};
/* Netgraph node type descriptor */
static struct ng_type typestruct = {
NG_ABI_VERSION,
NG_TTY_NODE_TYPE,
ngt_mod_event,
ngt_constructor,
ngt_rcvmsg,
ngt_shutdown,
ngt_newhook,
NULL,
ngt_connect,
ngt_rcvdata,
ngt_disconnect,
NULL
};
NETGRAPH_INIT(tty, &typestruct);
static int ngt_unit;
static int ngt_nodeop_ok; /* OK to create/remove node */
static int ngt_ldisc;
/******************************************************************
LINE DISCIPLINE METHODS
******************************************************************/
/*
* Set our line discipline on the tty.
* Called from device open routine or ttioctl() at >= splsofttty()
*/
static int
ngt_open(dev_t dev, struct tty *tp)
{
struct proc *const p = curproc; /* XXX */
char name[sizeof(NG_TTY_NODE_TYPE) + 8];
sc_p sc;
int s, error;
/* Super-user only */
if ((error = suser(p)))
return (error);
s = splnet();
(void) spltty(); /* XXX is this necessary? */
/* Already installed? */
if (tp->t_line == NETGRAPHDISC) {
sc = (sc_p) tp->t_sc;
if (sc != NULL && sc->tp == tp)
goto done;
}
/* Initialize private struct */
MALLOC(sc, sc_p, sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
if (sc == NULL) {
error = ENOMEM;
goto done;
}
sc->tp = tp;
sc->hotchar = NG_TTY_DFL_HOTCHAR;
sc->qtail = &sc->qhead;
QUEUECHECK(sc);
callout_handle_init(&sc->chand);
/* Setup netgraph node */
ngt_nodeop_ok = 1;
error = ng_make_node_common(&typestruct, &sc->node);
ngt_nodeop_ok = 0;
if (error) {
FREE(sc, M_NETGRAPH);
goto done;
}
snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
/* Set back pointers */
sc->node->private = sc;
tp->t_sc = (caddr_t) sc;
/* Assign node its name */
if ((error = ng_name_node(sc->node, name))) {
log(LOG_ERR, "%s: node name exists?\n", name);
ngt_nodeop_ok = 1;
ng_rmnode(sc->node);
ngt_nodeop_ok = 0;
goto done;
}
/*
* Pre-allocate cblocks to the an appropriate amount.
* I'm not sure what is appropriate.
*/
ttyflush(tp, FREAD | FWRITE);
clist_alloc_cblocks(&tp->t_canq, 0, 0);
clist_alloc_cblocks(&tp->t_rawq, 0, 0);
clist_alloc_cblocks(&tp->t_outq,
MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
done:
/* Done */
splx(s);
return (error);
}
/*
* Line specific close routine, called from device close routine
* and from ttioctl at >= splsofttty(). This causes the node to
* be destroyed as well.
*/
static int
ngt_close(struct tty *tp, int flag)
{
const sc_p sc = (sc_p) tp->t_sc;
int s;
s = spltty();
ttyflush(tp, FREAD | FWRITE);
clist_free_cblocks(&tp->t_outq);
tp->t_line = 0;
if (sc != NULL) {
if (sc->flags & FLG_TIMEOUT) {
untimeout(ngt_timeout, sc, sc->chand);
sc->flags &= ~FLG_TIMEOUT;
}
ngt_nodeop_ok = 1;
ng_rmnode(sc->node);
ngt_nodeop_ok = 0;
tp->t_sc = NULL;
}
splx(s);
return (0);
}
/*
* Once the device has been turned into a node, we don't allow reading.
*/
static int
ngt_read(struct tty *tp, struct uio *uio, int flag)
{
return (EIO);
}
/*
* Once the device has been turned into a node, we don't allow writing.
*/
static int
ngt_write(struct tty *tp, struct uio *uio, int flag)
{
return (EIO);
}
/*
* We implement the NGIOCGINFO ioctl() defined in ng_message.h.
*/
static int
ngt_tioctl(struct tty *tp, u_long cmd, caddr_t data, int flag, struct proc *p)
{
const sc_p sc = (sc_p) tp->t_sc;
int s, error = 0;
s = spltty();
switch (cmd) {
case NGIOCGINFO:
{
struct nodeinfo *const ni = (struct nodeinfo *) data;
const node_p node = sc->node;
bzero(ni, sizeof(*ni));
if (node->name)
strncpy(ni->name, node->name, sizeof(ni->name) - 1);
strncpy(ni->type, node->type->name, sizeof(ni->type) - 1);
ni->id = (u_int32_t) node;
ni->hooks = node->numhooks;
break;
}
default:
ERROUT(ENOIOCTL);
}
done:
splx(s);
return (error);
}
/*
* Receive data coming from the device. We get one character at
* a time, which is kindof silly.
* Only guaranteed to be at splsofttty() or spltty().
*/
static int
ngt_input(int c, struct tty *tp)
{
const sc_p sc = (sc_p) tp->t_sc;
const node_p node = sc->node;
struct mbuf *m;
int s, error = 0;
if (!sc || tp != sc->tp)
return (0);
s = spltty();
if (!sc->hook)
ERROUT(0);
/* Check for error conditions */
if ((tp->t_state & TS_CONNECTED) == 0) {
if (sc->flags & FLG_DEBUG)
log(LOG_DEBUG, "%s: no carrier\n", node->name);
ERROUT(0);
}
if (c & TTY_ERRORMASK) {
/* framing error or overrun on this char */
if (sc->flags & FLG_DEBUG)
log(LOG_DEBUG, "%s: line error %x\n",
node->name, c & TTY_ERRORMASK);
ERROUT(0);
}
c &= TTY_CHARMASK;
/* Get a new header mbuf if we need one */
if (!(m = sc->m)) {
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (!m) {
if (sc->flags & FLG_DEBUG)
log(LOG_ERR,
"%s: can't get mbuf\n", node->name);
ERROUT(ENOBUFS);
}
m->m_len = m->m_pkthdr.len = 0;
m->m_pkthdr.rcvif = NULL;
sc->m = m;
}
/* Add char to mbuf */
*mtod(m, u_char *) = c;
m->m_data++;
m->m_len++;
m->m_pkthdr.len++;
/* Ship off mbuf if it's time */
if (sc->hotchar == -1 || c == sc->hotchar || m->m_len >= MHLEN) {
m->m_data = m->m_pktdat;
NG_SEND_DATA_ONLY(error, sc->hook, m);
sc->m = NULL;
}
done:
splx(s);
return (error);
}
/*
* This is called when the device driver is ready for more output.
* Called from tty system at splsofttty() or spltty().
* Also call from ngt_rcv_data() when a new mbuf is available for output.
*/
static int
ngt_start(struct tty *tp)
{
const sc_p sc = (sc_p) tp->t_sc;
int s;
s = spltty();
while (tp->t_outq.c_cc < NGT_HIWATER) { /* XXX 2.2 specific ? */
struct mbuf *m = sc->qhead;
/* Remove first mbuf from queue */
if (!m)
break;
if ((sc->qhead = m->m_nextpkt) == NULL)
sc->qtail = &sc->qhead;
sc->qlen--;
QUEUECHECK(sc);
/* Send as much of it as possible */
while (m) {
struct mbuf *m2;
int sent;
sent = m->m_len
- b_to_q(mtod(m, u_char *), m->m_len, &tp->t_outq);
m->m_data += sent;
m->m_len -= sent;
if (m->m_len > 0)
break; /* device can't take no more */
MFREE(m, m2);
m = m2;
}
/* Put remainder of mbuf chain (if any) back on queue */
if (m) {
m->m_nextpkt = sc->qhead;
sc->qhead = m;
if (sc->qtail == &sc->qhead)
sc->qtail = &m->m_nextpkt;
sc->qlen++;
QUEUECHECK(sc);
break;
}
}
/* Call output process whether or not there is any output. We are
* being called in lieu of ttstart and must do what it would. */
if (tp->t_oproc != NULL)
(*tp->t_oproc) (tp);
/* This timeout is needed for operation on a pseudo-tty, because the
* pty code doesn't call pppstart after it has drained the t_outq. */
if (sc->qhead && (sc->flags & FLG_TIMEOUT) == 0) {
sc->chand = timeout(ngt_timeout, sc, 1);
sc->flags |= FLG_TIMEOUT;
}
splx(s);
return (0);
}
/*
* We still have data to output to the device, so try sending more.
*/
static void
ngt_timeout(void *arg)
{
const sc_p sc = (sc_p) arg;
int s;
s = spltty();
sc->flags &= ~FLG_TIMEOUT;
ngt_start(sc->tp);
splx(s);
}
/******************************************************************
NETGRAPH NODE METHODS
******************************************************************/
/*
* Initialize a new node of this type.
*
* We only allow nodes to be created as a result of setting
* the line discipline on a tty, so always return an error if not.
*/
static int
ngt_constructor(node_p *nodep)
{
if (!ngt_nodeop_ok)
return (EOPNOTSUPP);
return (ng_make_node_common(&typestruct, nodep));
}
/*
* Add a new hook. There can only be one.
*/
static int
ngt_newhook(node_p node, hook_p hook, const char *name)
{
const sc_p sc = node->private;
int s, error = 0;
if (strcmp(name, NG_TTY_HOOK))
return (EINVAL);
s = spltty();
if (sc->hook)
ERROUT(EISCONN);
sc->hook = hook;
done:
splx(s);
return (error);
}
/*
* set the hooks into queueing mode (for outgoing packets)
*/
static int
ngt_connect(hook_p hook)
{
hook->peer->flags |= HK_QUEUE;
return (0);
}
/*
* Disconnect the hook
*/
static int
ngt_disconnect(hook_p hook)
{
const sc_p sc = hook->node->private;
int s;
s = spltty();
if (hook != sc->hook)
panic(__FUNCTION__);
sc->hook = NULL;
m_freem(sc->m);
sc->m = NULL;
splx(s);
return (0);
}
/*
* Remove this node. The does the netgraph portion of the shutdown.
* This should only be called indirectly from ngt_close().
*/
static int
ngt_shutdown(node_p node)
{
const sc_p sc = node->private;
if (!ngt_nodeop_ok)
return (EOPNOTSUPP);
ng_unname(node);
ng_cutlinks(node);
node->private = NULL;
ng_unref(sc->node);
m_freem(sc->qhead);
m_freem(sc->m);
bzero(sc, sizeof(*sc));
FREE(sc, M_NETGRAPH);
return (0);
}
/*
* Receive incoming data from netgraph system. Put it on our
* output queue and start output if necessary.
*/
static int
ngt_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp)
{
const sc_p sc = hook->node->private;
int s, error = 0;
if (hook != sc->hook)
panic(__FUNCTION__);
NG_FREE_META(meta);
s = spltty();
if (sc->qlen >= MAX_MBUFQ)
ERROUT(ENOBUFS);
m->m_nextpkt = NULL;
*sc->qtail = m;
sc->qtail = &m->m_nextpkt;
sc->qlen++;
QUEUECHECK(sc);
m = NULL;
if (sc->qlen == 1)
ngt_start(sc->tp);
done:
splx(s);
if (m)
m_freem(m);
return (error);
}
/*
* Receive control message
*/
static int
ngt_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr,
struct ng_mesg **rptr, hook_p lasthook)
{
const sc_p sc = (sc_p) node->private;
struct ng_mesg *resp = NULL;
int error = 0;
switch (msg->header.typecookie) {
case NGM_TTY_COOKIE:
switch (msg->header.cmd) {
case NGM_TTY_SET_HOTCHAR:
{
int hotchar;
if (msg->header.arglen != sizeof(int))
ERROUT(EINVAL);
hotchar = *((int *) msg->data);
if (hotchar != (u_char) hotchar && hotchar != -1)
ERROUT(EINVAL);
sc->hotchar = hotchar; /* race condition is OK */
break;
}
case NGM_TTY_GET_HOTCHAR:
NG_MKRESPONSE(resp, msg, sizeof(int), M_NOWAIT);
if (!resp)
ERROUT(ENOMEM);
/* Race condition here is OK */
*((int *) resp->data) = sc->hotchar;
break;
default:
ERROUT(EINVAL);
}
break;
default:
ERROUT(EINVAL);
}
if (rptr)
*rptr = resp;
else if (resp)
FREE(resp, M_NETGRAPH);
done:
FREE(msg, M_NETGRAPH);
return (error);
}
/******************************************************************
INITIALIZATION
******************************************************************/
/*
* Handle loading and unloading for this node type
*/
static int
ngt_mod_event(module_t mod, int event, void *data)
{
/* struct ng_type *const type = data;*/
int s, error = 0;
switch (event) {
case MOD_LOAD:
/* Register line discipline */
s = spltty();
if ((ngt_ldisc = ldisc_register(NETGRAPHDISC, &ngt_disc)) < 0) {
splx(s);
log(LOG_ERR, "%s: can't register line discipline",
__FUNCTION__);
return (EIO);
}
splx(s);
break;
case MOD_UNLOAD:
/* Unregister line discipline */
s = spltty();
ldisc_deregister(ngt_ldisc);
splx(s);
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}