Filter determines whether a packet satisfies
specified condition. Actually Filter is
wrapper for bpf_program. For details of filter
expression, see tcpdump(1).
Objectcompile(expr, capture[, optimize[, netmask]])
new(expr, capture[, optimize[, netmask]])
Create a new Filter object.
expr is a filter string. capture
is a Capture object. optimize
controls optimization of resulting code.
netmask specifies the netmask of the local net.
Created Filter can be applied to packets
captured via capture.
If libpcap-0.5 or later
used, one of following values can be specified
instead of capture:
[snaplen, datalink]- an array containing required parameters
- omitted (or
nil)- Ethernet default (
[68,)DLT_EN10MB]
self === packet
self =~ packet
Return true if packet matches this filter.
~ self
Return a Filter which represents
"not self".
self | other
Return a Filter which represents
"self or other".
self & other
Return a Filter which represents
"self and other".
source
Returns the orginal string from which the filter is constructed.