Hi misc,
(this is on 4.6-stable, -current has the same issue)
I played around with our shiny new /32 and noticed that this is not
working:
$ sudo /sbin/route add -inet6 -prefixlen 48 2a00:15a8:6:: 2a00:15a8::3
$ route -n show -inet6 | fgrep 2a00:15a8::3
[...]
2a00:15a8:6::/64 2a00:15a8::3 UGS 0 0 - 8 em0
After some re-reading of route(8) and reading
/usr/src/sbin/route/route.c I figured out that I should be doing
something like this:
$ sudo /sbin/route add -inet6 2a00:15a8:6:: 2a00:15a8::3 -prefixlen 48
$ route -n show -inet6 | fgrep 2a00:15a8::3
[...]
2a00:15a8:6::/48 2a00:15a8::3 UGS 0 0 - 8 em0
$ sudo /sbin/route add -inet6 2a00:15a8:6:: -prefixlen 48 2a00:15a8::3
is working, too.
The obvious bug here is me not being able to call route the correct
way.
However, route's behavior in the first call is a bit strange, it
silently inserts a /64 route - ignoring the prefixlen.
The man page says:
The implicit network mask generated in the AF_INET case can be
overridden by making sure this option follows the destination
parameter.
-prefixlen is also available for a similar purpose, for IPv6/v4.
Earlier it states:
The other commands have the syntax:
route [-dnqtv] command [modifiers] destination gateway
I don't think it's clear (from this synopsis) that -prefixlen is part
of the destination or gateway, I thought it's part of [modifiers].
This behavior is caused by the way the command line is parsed.
The parsers sees -prefixlen, calls int prefixlen(char *s) and sets a
global variable (so_mask).
Later it parses the network address (2a00:15a8:6:: in my case) and
calls int inet6_makenetandmask(struct sockaddr_in6 *sin6).
This function tries to figure out a prefixlen (0 if it thinks it's a
default route and 64 if the lower 8 bytes of the address are zero) and
overwrites the previously set prefixlen by calling int prefixlen(char
*s) again.
It would be nice if route refuses to do anything in the first call,
it's syntacticly and semanticly wrong or at least warn that it's
ignoring -prefixlen and inserting a /64 instead.
Best regards,
Florian
