FreeBSD-5.3/sys/netgraph/ng_tty.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: src/sys/netgraph/ng_tty.c,v 1.29.2.1 2004/09/03 03:12:57 rwatson Exp $
* $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>
NET_NEEDS_GIANT("ng_tty");
/* 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("%s: queue", __func__); \
} while (0)
#else
#define QUEUECHECK(sc) do {} while (0)
#endif
/* Line discipline methods */
static int ngt_open(struct cdev *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 thread *);
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
};
/* Netgraph node type descriptor */
static struct ng_type typestruct = {
.version = NG_ABI_VERSION,
.name = NG_TTY_NODE_TYPE,
.mod_event = ngt_mod_event,
.constructor = ngt_constructor,
.rcvmsg = ngt_rcvmsg,
.shutdown = ngt_shutdown,
.newhook = ngt_newhook,
.connect = ngt_connect,
.rcvdata = ngt_rcvdata,
.disconnect = ngt_disconnect,
};
NETGRAPH_INIT(tty, &typestruct);
/*
* XXXRW: ngt_unit is protected by ng_tty_mtx. ngt_ldisc is constant once
* ng_tty is initialized. ngt_nodeop_ok is untouched, and might want to be a
* sleep lock in the future?
*/
static int ngt_unit;
static int ngt_nodeop_ok; /* OK to create/remove node */
static int ngt_ldisc;
static struct mtx ng_tty_mtx;
MTX_SYSINIT(ng_tty, &ng_tty_mtx, "ng_tty", MTX_DEF);
/******************************************************************
LINE DISCIPLINE METHODS
******************************************************************/
/*
* Set our line discipline on the tty.
* Called from device open routine or ttioctl() at >= splsofttty()
*/
static int
ngt_open(struct cdev *dev, struct tty *tp)
{
struct thread *const td = curthread; /* XXX */
char name[sizeof(NG_TTY_NODE_TYPE) + 8];
sc_p sc;
int s, error;
/* Super-user only */
if ((error = suser(td)))
return (error);
s = splnet();
(void) spltty(); /* XXX is this necessary? */
tp->t_hotchar = NG_TTY_DFL_HOTCHAR;
/* 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;
}
mtx_lock(&ng_tty_mtx);
snprintf(name, sizeof(name), "%s%d", typestruct.name, ngt_unit++);
mtx_unlock(&ng_tty_mtx);
/* 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_NODE_UNREF(sc->node);
ngt_nodeop_ok = 0;
goto done;
}
/* Set back pointers */
NG_NODE_SET_PRIVATE(sc->node, sc);
tp->t_sc = (caddr_t) sc;
/*
* 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);
if (sc != NULL) {
if (sc->flags & FLG_TIMEOUT) {
untimeout(ngt_timeout, sc, sc->chand);
sc->flags &= ~FLG_TIMEOUT;
}
ngt_nodeop_ok = 1;
ng_rmnode_self(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 thread *td)
{
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 (NG_NODE_HAS_NAME(node))
strncpy(ni->name, NG_NODE_NAME(node), sizeof(ni->name) - 1);
strncpy(ni->type, node->nd_type->name, sizeof(ni->type) - 1);
ni->id = (u_int32_t) ng_node2ID(node);
ni->hooks = NG_NODE_NUMHOOKS(node);
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", NG_NODE_NAME(node));
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",
NG_NODE_NAME(node), 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", NG_NODE_NAME(node));
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) {
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 */
m = m_free(m);
}
/* 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 node)
{
return (EOPNOTSUPP);
}
/*
* 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 = NG_NODE_PRIVATE(node);
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)
* Force single client at a time.
*/
static int
ngt_connect(hook_p hook)
{
/*NG_HOOK_FORCE_WRITER(hook);
NG_HOOK_FORCE_QUEUE(NG_HOOK_PEER(hook));*/
return (0);
}
/*
* Disconnect the hook
*/
static int
ngt_disconnect(hook_p hook)
{
const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
int s;
s = spltty();
if (hook != sc->hook)
panic(__func__);
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 = NG_NODE_PRIVATE(node);
if (!ngt_nodeop_ok)
return (EOPNOTSUPP);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_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, item_p item)
{
const sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
int s, error = 0;
struct mbuf *m;
if (hook != sc->hook)
panic(__func__);
NGI_GET_M(item, m);
NG_FREE_ITEM(item);
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, item_p item, hook_p lasthook)
{
const sc_p sc = NG_NODE_PRIVATE(node);
struct ng_mesg *resp = NULL;
int error = 0;
struct ng_mesg *msg;
NGI_GET_MSG(item, msg);
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);
}
done:
NG_RESPOND_MSG(error, node, item, resp);
NG_FREE_MSG(msg);
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",
__func__);
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);
}