freebsd-skq/usr.sbin/ppp/tty.c
brian 659744dd68 Rewrite the link descriptor transfer code in MP mode.
Previously, ppp attempted to bind() to a local domain tcp socket
based on the peer authname & enddisc.  If it succeeded, it listen()ed
and became MP server.  If it failed, it connect()ed and became MP
client.  The server then select()ed on the descriptor, accept()ed
it and wrote its pid to it then read the link data & link file descriptor,
and finally sent an ack (``!'').  The client would read() the server
pid, transfer the link lock to that pid, send the link data & descriptor
and read the ack.  It would then close the descriptor and clean up.

There was a race between the bind() and listen() where someone could
attempt to connect() and fail.

This change removes the race.  Now ppp makes the RCVBUF big enough on a
socket descriptor and attempts to bind() to a local domain *udp* socket
(same name as before).  If it succeeds, it becomes MP server.  If it
fails, it sets the SNDBUF and connect()s, becoming MP client.  The server
select()s on the descriptor and recvmsg()s the message, insisting on at
least two descriptors (plus the link data).  It uses the second descriptor
to write() its pid then read()s an ack (``!'').  The client creates a
socketpair() and sendmsg()s the link data, link descriptor and one of
the socketpair descriptors.  It then read()s the server pid from the
other socketpair descriptor, transfers any locks and write()s an ack.

Now, there can be no race, and a connect() failure indicates a stale
socket file.

This also fixes MP ppp over ethernet, where the struct msghdr was being
misconstructed when transferring the control socket descriptor.

Also, if we fail to send the link, don't hang around in a ``session
owner'' state, just do the setsid() and fork() if it's required to
disown a tty.

UDP idea suggested by: Chris Bennet from Mindspring at FreeBSDCon
1999-11-25 02:47:04 +00:00

456 lines
12 KiB
C

/*-
* Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON 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 ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/un.h>
#if defined(__OpenBSD__) || defined(__NetBSD__)
#include <sys/ioctl.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <sys/uio.h>
#include <termios.h>
#include <unistd.h>
#include "layer.h"
#include "defs.h"
#include "mbuf.h"
#include "log.h"
#include "timer.h"
#include "lqr.h"
#include "hdlc.h"
#include "throughput.h"
#include "fsm.h"
#include "lcp.h"
#include "ccp.h"
#include "link.h"
#include "async.h"
#include "descriptor.h"
#include "physical.h"
#include "mp.h"
#include "chat.h"
#include "auth.h"
#include "chap.h"
#include "cbcp.h"
#include "datalink.h"
#include "main.h"
#include "tty.h"
#if defined(__mac68k__) || defined(__macppc__)
#undef CRTS_IFLOW
#undef CCTS_OFLOW
#define CRTS_IFLOW CDTRCTS
#define CCTS_OFLOW CDTRCTS
#endif
#define Online(dev) ((dev)->mbits & TIOCM_CD)
struct ttydevice {
struct device dev; /* What struct physical knows about */
struct pppTimer Timer; /* CD checks */
int mbits; /* Current DCD status */
int carrier_seconds; /* seconds before CD is *required* */
struct termios ios; /* To be able to reset from raw mode */
};
#define device2tty(d) ((d)->type == TTY_DEVICE ? (struct ttydevice *)d : NULL)
int
tty_DeviceSize(void)
{
return sizeof(struct ttydevice);
}
/*
* tty_Timeout() watches the DCD signal and mentions it if it's status
* changes.
*/
static void
tty_Timeout(void *data)
{
struct physical *p = data;
struct ttydevice *dev = device2tty(p->handler);
int ombits, change;
timer_Stop(&dev->Timer);
dev->Timer.load = SECTICKS; /* Once a second please */
timer_Start(&dev->Timer);
ombits = dev->mbits;
if (p->fd >= 0) {
if (ioctl(p->fd, TIOCMGET, &dev->mbits) < 0) {
/* we must be a pty ? */
log_Printf(LogDEBUG, "%s: ioctl error (%s)!\n", p->link.name,
strerror(errno));
timer_Stop(&dev->Timer);
return;
}
} else
dev->mbits = 0;
if (ombits == -1) {
/* First time looking for carrier */
if (Online(dev))
log_Printf(LogPHASE, "%s: %s: CD detected\n", p->link.name, p->name.full);
else if (++dev->carrier_seconds >= p->cfg.cd.delay) {
if (p->cfg.cd.necessity == CD_REQUIRED)
log_Printf(LogPHASE, "%s: %s: Required CD not detected\n",
p->link.name, p->name.full);
else {
log_Printf(LogPHASE, "%s: %s doesn't support CD\n",
p->link.name, p->name.full);
dev->mbits = TIOCM_CD; /* Dodgy null-modem cable ? */
}
timer_Stop(&dev->Timer);
/* tty_AwaitCarrier() will notice */
} else {
/* Keep waiting */
log_Printf(LogDEBUG, "%s: %s: Still no carrier (%d/%d)\n",
p->link.name, p->name.full, dev->carrier_seconds,
p->cfg.cd.delay);
dev->mbits = -1;
}
} else {
change = ombits ^ dev->mbits;
if (change & TIOCM_CD) {
if (dev->mbits & TIOCM_CD)
log_Printf(LogDEBUG, "%s: offline -> online\n", p->link.name);
else {
log_Printf(LogDEBUG, "%s: online -> offline\n", p->link.name);
log_Printf(LogPHASE, "%s: Carrier lost\n", p->link.name);
datalink_Down(p->dl, CLOSE_NORMAL);
timer_Stop(&dev->Timer);
}
} else
log_Printf(LogDEBUG, "%s: Still %sline\n", p->link.name,
Online(dev) ? "on" : "off");
}
}
static void
tty_StartTimer(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
timer_Stop(&dev->Timer);
dev->Timer.load = SECTICKS;
dev->Timer.func = tty_Timeout;
dev->Timer.name = "tty CD";
dev->Timer.arg = p;
log_Printf(LogDEBUG, "%s: Using tty_Timeout [%p]\n",
p->link.name, tty_Timeout);
timer_Start(&dev->Timer);
}
static int
tty_AwaitCarrier(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
if (p->cfg.cd.necessity == CD_NOTREQUIRED || physical_IsSync(p))
return CARRIER_OK;
if (dev->mbits == -1) {
if (dev->Timer.state == TIMER_STOPPED) {
dev->carrier_seconds = 0;
tty_StartTimer(p);
}
return CARRIER_PENDING; /* Not yet ! */
}
return Online(dev) || !p->cfg.cd.necessity == CD_REQUIRED ?
CARRIER_OK : CARRIER_LOST;
}
static int
tty_Raw(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
struct termios ios;
int oldflag;
log_Printf(LogDEBUG, "%s: Entering tty_Raw\n", p->link.name);
if (p->type != PHYS_DIRECT && p->fd >= 0 && !Online(dev))
log_Printf(LogDEBUG, "%s: Raw: descriptor = %d, mbits = %x\n",
p->link.name, p->fd, dev->mbits);
if (!physical_IsSync(p)) {
tcgetattr(p->fd, &ios);
cfmakeraw(&ios);
if (p->cfg.rts_cts)
ios.c_cflag |= CLOCAL | CCTS_OFLOW | CRTS_IFLOW;
else
ios.c_cflag |= CLOCAL;
if (p->type != PHYS_DEDICATED)
ios.c_cflag |= HUPCL;
tcsetattr(p->fd, TCSANOW, &ios);
}
oldflag = fcntl(p->fd, F_GETFL, 0);
if (oldflag < 0)
return 0;
fcntl(p->fd, F_SETFL, oldflag | O_NONBLOCK);
return 1;
}
static void
tty_Offline(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
if (p->fd >= 0) {
timer_Stop(&dev->Timer);
dev->mbits &= ~TIOCM_DTR; /* XXX: Hmm, what's this supposed to do ? */
if (Online(dev)) {
struct termios tio;
tcgetattr(p->fd, &tio);
if (cfsetspeed(&tio, B0) == -1)
log_Printf(LogWARN, "%s: Unable to set physical to speed 0\n",
p->link.name);
else
tcsetattr(p->fd, TCSANOW, &tio);
}
}
}
static void
tty_Cooked(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
int oldflag;
tty_Offline(p); /* In case of emergency close()s */
tcflush(p->fd, TCIOFLUSH);
if (!physical_IsSync(p))
tcsetattr(p->fd, TCSAFLUSH, &dev->ios);
if ((oldflag = fcntl(p->fd, F_GETFL, 0)) != -1)
fcntl(p->fd, F_SETFL, oldflag & ~O_NONBLOCK);
}
static void
tty_StopTimer(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
timer_Stop(&dev->Timer);
}
static void
tty_Free(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
tty_Offline(p); /* In case of emergency close()s */
free(dev);
}
static int
tty_Speed(struct physical *p)
{
struct termios ios;
if (tcgetattr(p->fd, &ios) == -1)
return 0;
return SpeedToInt(cfgetispeed(&ios));
}
static const char *
tty_OpenInfo(struct physical *p)
{
struct ttydevice *dev = device2tty(p->handler);
static char buf[13];
if (Online(dev))
strcpy(buf, "with");
else
strcpy(buf, "no");
strcat(buf, " carrier");
return buf;
}
static void
tty_device2iov(struct device *d, struct iovec *iov, int *niov,
int maxiov, int *auxfd, int *nauxfd)
{
struct ttydevice *dev = device2tty(d);
int sz = physical_MaxDeviceSize();
iov[*niov].iov_base = realloc(d, sz);
if (iov[*niov].iov_base == NULL) {
log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz);
AbortProgram(EX_OSERR);
}
iov[*niov].iov_len = sz;
(*niov)++;
if (dev->Timer.state != TIMER_STOPPED) {
timer_Stop(&dev->Timer);
dev->Timer.state = TIMER_RUNNING;
}
}
static struct device basettydevice = {
TTY_DEVICE,
"tty",
tty_AwaitCarrier,
NULL,
tty_Raw,
tty_Offline,
tty_Cooked,
tty_StopTimer,
tty_Free,
NULL,
NULL,
tty_device2iov,
tty_Speed,
tty_OpenInfo
};
struct device *
tty_iov2device(int type, struct physical *p, struct iovec *iov, int *niov,
int maxiov, int *auxfd, int *nauxfd)
{
if (type == TTY_DEVICE) {
struct ttydevice *dev = (struct ttydevice *)iov[(*niov)++].iov_base;
dev = realloc(dev, sizeof *dev); /* Reduce to the correct size */
if (dev == NULL) {
log_Printf(LogALERT, "Failed to allocate memory: %d\n",
(int)(sizeof *dev));
AbortProgram(EX_OSERR);
}
/* Refresh function pointers etc */
memcpy(&dev->dev, &basettydevice, sizeof dev->dev);
physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
if (dev->Timer.state != TIMER_STOPPED) {
dev->Timer.state = TIMER_STOPPED;
p->handler = &dev->dev; /* For the benefit of StartTimer */
tty_StartTimer(p);
}
return &dev->dev;
}
return NULL;
}
struct device *
tty_Create(struct physical *p)
{
struct ttydevice *dev;
struct termios ios;
int oldflag;
if (p->fd < 0 || !isatty(p->fd))
/* Don't want this */
return NULL;
if (*p->name.full == '\0') {
physical_SetDevice(p, ttyname(p->fd));
log_Printf(LogDEBUG, "%s: Input is a tty (%s)\n",
p->link.name, p->name.full);
} else
log_Printf(LogDEBUG, "%s: Opened %s\n", p->link.name, p->name.full);
/* We're gonna return a ttydevice (unless something goes horribly wrong) */
if ((dev = malloc(sizeof *dev)) == NULL) {
/* Complete failure - parent doesn't continue trying to ``create'' */
close(p->fd);
p->fd = -1;
return NULL;
}
memcpy(&dev->dev, &basettydevice, sizeof dev->dev);
memset(&dev->Timer, '\0', sizeof dev->Timer);
dev->mbits = -1;
tcgetattr(p->fd, &ios);
dev->ios = ios;
log_Printf(LogDEBUG, "%s: tty_Create: physical (get): fd = %d,"
" iflag = %lx, oflag = %lx, cflag = %lx\n", p->link.name, p->fd,
(u_long)ios.c_iflag, (u_long)ios.c_oflag, (u_long)ios.c_cflag);
cfmakeraw(&ios);
if (p->cfg.rts_cts)
ios.c_cflag |= CLOCAL | CCTS_OFLOW | CRTS_IFLOW;
else {
ios.c_cflag |= CLOCAL;
ios.c_iflag |= IXOFF;
}
ios.c_iflag |= IXON;
if (p->type != PHYS_DEDICATED)
ios.c_cflag |= HUPCL;
if (p->type != PHYS_DIRECT) {
/* Change tty speed when we're not in -direct mode */
ios.c_cflag &= ~(CSIZE | PARODD | PARENB);
ios.c_cflag |= p->cfg.parity;
if (cfsetspeed(&ios, IntToSpeed(p->cfg.speed)) == -1)
log_Printf(LogWARN, "%s: %s: Unable to set speed to %d\n",
p->link.name, p->name.full, p->cfg.speed);
}
tcsetattr(p->fd, TCSADRAIN, &ios);
log_Printf(LogDEBUG, "%s: physical (put): iflag = %lx, oflag = %lx, "
"cflag = %lx\n", p->link.name, (u_long)ios.c_iflag,
(u_long)ios.c_oflag, (u_long)ios.c_cflag);
oldflag = fcntl(p->fd, F_GETFL, 0);
if (oldflag < 0) {
/* Complete failure - parent doesn't continue trying to ``create'' */
log_Printf(LogWARN, "%s: Open: Cannot get physical flags: %s\n",
p->link.name, strerror(errno));
tty_Cooked(p);
close(p->fd);
p->fd = -1;
free(dev);
return NULL;
} else
fcntl(p->fd, F_SETFL, oldflag & ~O_NONBLOCK);
physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
return &dev->dev;
}