[PATCH net-next 0/8] ipv6: fib6: socket dst_entry improvments and cleanups

[Hannes Frederic Sowa <hannes@stressinduktion.org>]

Eric Dumazet noticed that rt6_nodes wich are neither RTF_NONEXTHOP nor
RTF_GATEWAY but DST_HOST ones cause major routing lookup churn because
their rt6_genid is never renewed, thus ip6_dst_check always considers
them outdated. This is a major problem, because these kind of routes
are normally used to in input handling.

Thus it does not make sense to use rt6i_genid anymore. This series
removes it.

The address deletion path is already covered and does not depend on
rt6i_genid. When we add a new address, we update the fn_sernums while
traversing the tree.

Because inet6_connect_socket depend on dst_check returning NULL also
for source address invalidation, we currently have to walk the whole
tree and update the fn_sernums manually when an address gets deleted.
This is a fairly expensive operation we currenlty have to do for address
deletion and xfrm policy changes. We currently do that for interface
mtu changes already.

I dropped the patch for updating the fn_sernum on deletion as it
showed some side effects with /proc/net/ipv6_route and we currently
don't need it. I stashed it away.

Thanks to Eric Dumazet for noticing the problem with rt6i_genid!

Hannes Frederic Sowa (8):
  ipv6: support for fib6_clean_* to update fn_sernum
  ipv6: a bit more typesafety
  ipv6: only generate one new serial number during fib6_add()
  ipv6: if no function for cleaner is specified only visit fib6_nodes
  ipv6: new function fib6_flush_trees and use it instead of bumping
    removed rt6_genid
  ipv6: no need to bump rt_genid_ipv6 on address addition
  ipv6: keep rt_sernum per namespace to reduce number of flushes
  ipv6: switch rt_sernum to atomic_t and clean up types

 include/net/ip6_fib.h       | 16 ++++++--
 include/net/net_namespace.h | 14 ++-----
 include/net/netns/ipv6.h    |  2 +-
 net/ipv6/addrconf.c         |  3 +-
 net/ipv6/addrconf_core.c    |  6 +++
 net/ipv6/af_inet6.c         |  2 +-
 net/ipv6/ip6_fib.c          | 90 +++++++++++++++++++++++++++------------------
 net/ipv6/route.c            |  4 --
 8 files changed, 81 insertions(+), 56 deletions(-)

-- 
1.9.3