Once the final component of the IP address has been parsed, the offset on the input must not be advanced, as this would remove an unparsed character from the input.
After looking at your abandoned review (D26420) where you add parsing of IPv6 addresses. I wondered if we could use the generic inet_aton(3) functions available from kernel space?
P/S. Please add full context to your patches.
svn diff --diff-cmd = diff -x -U999999> change.diff