=head1 NAME

extcap - Extcap grammar elements

=head1 SYNOPSIS

Suggested config grammar elements:
arg (options)       argument for CLI calling
number  Reference # of argument for other values, display order
call        Literal argument to call (--call=...)
display     Displayed name
default     Default value, in proper form for type
range       Range of valid values for UI checking (min,max) in proper form
type        Argument type for UI filtering for raw, or UI type for selector:
        integer
        unsigned
        long (may include scientific / special notation)
float
menu (display popup menu in UI)
selector (display selector table, all values as strings)
boolean (display checkbox)
radio (display group of radio buttons with provided values, all values as strings)

value (options) Values for argument selection
    arg     Argument # this value applies to
value       Passed value
display     Displayed value
default     Boolean (true if default, all others ignored, ie default=true)

flag (options)      external-capture level flags
    dedicated   Bypass dumpcap & mux for high speed
    failure     Failure message


Possible grammar example:

arg {number=0}{call=channel}{display=Wi-Fi Channel}{type=integer}
arg {number=1}{call=chanflags}{display=Channel Flags}{type=radio}
arg {number=2}{call=interface}{display=Interface}{type=selector}
value {arg=0}{range=1,11}
value {arg=1}{value=ht40p}{display=HT40+}
value {arg=1}{value=ht40m}{display=HT40-}
value {arg=1}{value=ht20}{display=HT20}
value {arg=2}{value=wlan0}{display=wlan0}

Example 2
arg {number=0}{call=usbdevice}{USB Device}{type=selector}
value {arg=0}{call=/dev/sysfs/usb/foo/123}{display=Ubertooth One sn 1234}
value {arg=0}{call=”/dev/sysfs/usb/foo/456}{display=Ubertooth One sn 8901}

Example 3
arg {number=0}{call=usbdevice}{USB Device}{type=selector}
flag {failure=Permission denied opening Ubertooth device}


Security awareness:

- Users running wireshark as root, we can’t save you
- Dumpcap retains suid/setgid and group+x permissions to allow users in wireshark group only
- Third-party capture programs run w/ whatever privs they’re installed with
- If an attacker can write to a system binary directory, we’re game over anyhow
- Don’t let wireshark be told to look for capture binaries somewhere else?

Notes:
- daemonized dumpcap?
- multiuser?
- sync_pipe.h commands
- expand pipe commands to have status notifications, etc?
- Wireshark->dumpcap options for channel control, etc?

TODO
define grammar
write grammar to HTML mockup
sketch interface with dumpcap
launch external-pcap from wireshark, bypass dumpcap
launch external-pcap from wireshark, hand fd to dumpcap
extract netif capture as first cap source