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.
self === packet
self =~ packet
Return true if packet matches this filter.