isdninfo - ISDN status device
/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.
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
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 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 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-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
channel is inactive.
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.
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.
Fritz Elfert <fritz@isdn4linux.de>