ISDNINFO(4)           Special files
          ISDNINFO(4)
NAME
isdninfo - ISDN status device
SYNOPSIS
#include <linux/isdn.h>
DESCRIPTION
/dev/isdninfo is a character device with major number 45 and minor
number 255. It delivers status information from the Linux ISDN subsystem to
user level.
DATA FORMAT
When reading from this device, the current status of the Linux ISDN subsystem
is delivered in 6 lines of text. Each line starts with a tag string followed
by a colon and whitespace. After that the status values are appended sepa-
rated by whitespace.
idmap
is the tag of the first line. In this line for every virtual channel,
the Id-string of the corresponding lowlevel driver is shown. If no
driver is loaded, a - (hyphen) is shown.
chmap
is the tag of line 2. In this line for every virtual channel, the
channel number of the corresponding lowlevel driver is shown. If no
driver is loaded, -1 is shown.
drmap
is the tag of line 3. In this line for every virtual channel, the
index number of the corresponding lowlevel driver is shown. If no
driver is loaded, -1 is shown.
usage
is the tag of line 4. In this line for every virtual channel, the cur-
rent usage is shown. The following usage constants are defined:
ISDN_USAGE_NONE (0)
Unused channel
ISDN_USAGE_RAW (1)
Channel used by raw device (currently unsupported)
ISDN_USAGE_MODEM (2)
Channel used by some ttyI
ISDN_USAGE_NET (3)
Channel used by an ISDN net-interface
ISDN_USAGE_VOICE (4)
Channel used by some ttyI in voice mode.
ISDN_USAGE_EXCLUSIVE (64)
Channel exclusively preserved for a net-interface. This value
is logically or'ed with one of the other codes.
ISDN_USAGE_OUTGOING (128)
Channel is used outgoing. This value is logically or'ed with
one of the other codes. It is set, when dialling is started and
reset, when either dialling failed or after hangup. Therefore,
it is not always an indicator for an established connection. To
get a reliable indicator for an established connection, the
driver flags (see below) have to be inspected also.
flags
is the tag of line 5. In this line for every driver slot, it's B-Chan-
nel status is shown. If no driver is registered in a slot, a ? is
shown. For every established B-Channel of the driver, a bit is set in
the shown value. The driver's first channel is mapped to bit 0, the
second channel to bit 1 and so on.
phone
is the tag of line 6. In this line for every virtual channel, the
remote phone number is shown if the channel is active. A ??? is shown,
if the channel is inactive.
BLOCKING BEHAVIOUR
After opening the device, at most 6 lines can be read by a user process.
After that, the user process is blocked. Whenever a status change happens,
the process is allowed to read 6 more lines, starting with line one.
IOCTL FUNCTIONS
Currently, there are two ioctl calls supported:
IIOCGETDVR
Get Revision information.
Returns an unsigned long value v, representing various user level
interface revisions, where
(v & 0xff)
is the revision of the modem-register info, available via ioctl
on /dev/isdnctrl.
((v >> 8) & 0xff)
is the revision of the net-interface config data, available via
ioctl on /dev/isdnctrl. and
((v >> 16) & 0xff)
is the revision of the data delivered via /dev/isdninfo
itself.
IIOCGETCPS
Get transfer statistics.
Returns the number of bytes transferred so far for all virtual chan-
nels. The third parameter should be a pointer to an array of unsigned
long of size ISDN_MAX_CHANNELS * 2. This array is filled with the byte
counter values upon return.
OTHER CONSTANTS
There are some more useful constants defined in /usr/include/linux/isdn.h:
ISDN_TTY_MAJOR
The major device number of /dev/ttyI.
ISDN_TTYAUX_MAJOR
The major device number of /dev/cui.
ISDN_MAJOR
The major device number of /dev/isdnctrl, /dev/isdninfo,
/dev/ippp and /dev/isdn
ISDN_MAX_DRIVERS
The number of driver slots.
ISDN_MAX_CHANNELS
The number of virtual channels.
ISDN_MINOR_CTRL
The minor device number of /dev/isdnctrl0.
ISDN_MINOR_CTRLMAX
The minor device number of /dev/isdnctrl63.
ISDN_MINOR_PPP
The minor device number of /dev/ippp0.
ISDN_MINOR_PPPMAX
The minor device number of /dev/ippp64.
ISDN_MINOR_STATUS
The minor device number of /dev/isdninfo.
Other constants, necessary for ioctl's on /dev/isdnctrl are listed in isdnc-
trl(4).