isdninfo - phpMan

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 separated 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 num-
ber 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 current
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 log-
ically 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 indica-
tor 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-Channel
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 chan-
nel 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 channels. 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 isdnctrl(4).

AUTHOR
Fritz Elfert <fritz AT isdn4linux.de>