scan_ip6if parses an IPv6 number in RFC1884 ASCII representation
from src and writes the result into ip. If the IPv6 number
is followed by the percent sign, scan_ip6if takes the word following
that, tries to parse it as network interface and writes the result to
It returns the number of bytes read from src or 0 if the parsing
scan_ip6if accepts upper and lower case hex letters, it understands "::"
compression and partial IPv4 addresses as in "::FFFF:126.96.36.199".
To allow transparent usage of IPv4 in IPv6 applications, scan_ip6if also
understands IPv4 addresses in dotted-decimal notation and will return
an IPv4-mapped IPv6 address (i.e. "127.0.0.1" will be parsed as
Unlike many other IP parsing routines, scan_ip6if does not recognize octal
(like 0188.8.131.52) or hexadecimal numbers (like 0x7f000001)
in the IPv4 part.