CVS commit: src/sys/netinet6

["Ryota Ozaki" <ozaki-r%netbsd.org@localhost>]

Module Name:    src
Committed By:   ozaki-r
Date:           Thu Nov 10 04:13:53 UTC 2016

Modified Files:
        src/sys/netinet6: in6_src.c ip6_output.c ip6_var.h

Log Message:
Tidy up in6_select*

This change tidies up in6_select* functions, especially
selectroute.

selectroute is annoying because:
- It returns both/either of a rtentry and/or an ifp
  - Yes, it may return only an ifp!
    - It is valid but selectroute shouldn't handle the case
  - Such conditional behavior makes it difficult
    to apply locking/psref thingy
- It may return a rtentry even if error
- It may use opt->ip6po_nextroute rtcache implicitly
  - The caller can know if it is used
    by rtcache_validate(&opt->ip6po_nextroute)
    but it's racy in MP-safe world
  - Even if it uses opt->ip6po_nextroute, it may
    return a rtentry that isn't derived from the rtcache

The change includes:
- Rename selectroute to in6_selectroute
  - Let a remaining caller of selectroute, in6_selectif,
    use in6_selectroute instead
- Let in6_selectroute return only an rtentry
  - If error, it doesn't return an rtentry
  - A caller gets an ifp from a returned rtentry
- Allow in6_selectroute to modify a passed rtcache
  and a caller can know if opt->ip6po_nextroute is
  used via the rtcache
- Let callers (ip6_output and in6_selectif) handle
  the case that only an ifp is required

Inspired by OpenBSD
Proposed on tech-kern and tech-net
LGTM by roy@


To generate a diff of this commit:
cvs rdiff -u -r1.73 -r1.74 src/sys/netinet6/in6_src.c
cvs rdiff -u -r1.177 -r1.178 src/sys/netinet6/ip6_output.c
cvs rdiff -u -r1.69 -r1.70 src/sys/netinet6/ip6_var.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.