xff_extract: Take vectors of IPs and X-Forwarded-For headers and produce single, normalised
IP addresses.
Description
xff_extract takes IP addresses and x_forwarded_for
values and, in the event that x_forwarded_for is non-null, attempts to
extract the "real" IP closest to the client.
Usage
xff_extract(ip_addresses, x_forwarded_for)
Arguments
ip_addresses
a vector of IP addresses
x_forwarded_for
an equally-sized vector of X-Forwarded-For header
contents.
Value
a vector of IP addresses, incorporating the XFF header value
where appropriate.