The ip6 GRE tap device should not be forced to down state to change
the mac address and should allow live address change for tap device
similar to ipv4 gre.

Signed-off-by: Shweta Choudaha <schoudah@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

At present we perform an xfrm_lookup() for each UDPv6 message we
send. The lookup involves querying the flow cache (flow_cache_lookup)
and, in case of a cache miss, creating an XFRM bundle.

If we miss the flow cache, we can end up creating a new bundle and
deriving the path MTU (xfrm_init_pmtu) from on an already transformed
dst_entry, which we pass from the socket cache (sk->sk_dst_cache) down
to xfrm_lookup(). This can happen only if we're caching the dst_entry
in the socket, that is when we're using a connected UDP socket.

To put it another way, the path MTU shrinks each time we miss the flow
cache, which later on leads to incorrectly fragmented payload. It can
be observed with ESPv6 in transport mode:

  1) Set up a transformation and lower the MTU to trigger fragmentation
    # ip xfrm policy add dir out src ::1 dst ::1 \
      tmpl src ::1 dst ::1 proto esp spi 1
    # ip xfrm state add src ::1 dst ::1 \
      proto esp spi 1 enc 'aes' 0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
    # ip link set dev lo mtu 1500

  2) Monitor the packet flow and set up an UDP sink
    # tcpdump -ni lo -ttt &
    # socat udp6-listen:12345,fork /dev/null &

  3) Send a datagram that needs fragmentation with a connected socket
    # perl -e 'print "@" x 1470 | socat - udp6:[::1]:12345
    2016/06/07 18:52:52 socat[724] E read(3, 0x555bb3d5ba00, 8192): Protocol error
    00:00:00.000000 IP6 ::1 > ::1: frag (0|1448) ESP(spi=0x00000001,seq=0x2), length 1448
    00:00:00.000014 IP6 ::1 > ::1: frag (1448|32)
    00:00:00.000050 IP6 ::1 > ::1: ESP(spi=0x00000001,seq=0x3), length 1272
    (^ ICMPv6 Parameter Problem)
    00:00:00.000022 IP6 ::1 > ::1: ESP(spi=0x00000001,seq=0x5), length 136

  4) Compare it to a non-connected socket
    # perl -e 'print "@" x 1500' | socat - udp6-sendto:[::1]:12345
    00:00:40.535488 IP6 ::1 > ::1: frag (0|1448) ESP(spi=0x00000001,seq=0x6), length 1448
    00:00:00.000010 IP6 ::1 > ::1: frag (1448|64)

What happens in step (3) is:

  1) when connecting the socket in __ip6_datagram_connect(), we
     perform an XFRM lookup, miss the flow cache, create an XFRM
     bundle, and cache the destination,

  2) afterwards, when sending the datagram, we perform an XFRM lookup,
     again, miss the flow cache (due to mismatch of flowi6_iif and
     flowi6_oif, which is an issue of its own), and recreate an XFRM
     bundle based on the cached (and already transformed) destination.

To prevent the recreation of an XFRM bundle, avoid an XFRM lookup
altogether whenever we already have a destination entry cached in the
socket. This prevents the path MTU shrinkage and brings us on par with
UDPv4.

The fix also benefits connected PINGv6 sockets, another user of
ip6_sk_dst_lookup_flow(), who also suffer messages being transformed
twice.

Joint work with Hannes Frederic Sowa.

Reported-by: Jan Tluka <jtluka@redhat.com>
Signed-off-by: Jakub Sitnicki <jkbs@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

The v6 tcp stats scan do not provide TLP and ER timer information
correctly like the v4 version . This patch fixes that.

Fixes: 6ba8a3b19e76 ("tcp: Tail loss probe (TLP)")
Fixes: eed530b6c676 ("tcp: early retransmit")
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Paul Moore tracked a regression caused by a recent commit, which
mistakenly assumed that sk_filter() could be avoided if socket
had no current BPF filter.

The intent was to avoid udp_lib_checksum_complete() overhead.

But sk_filter() also checks skb_pfmemalloc() and
security_sock_rcv_skb(), so better call it.

Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Paul Moore <paul@paul-moore.com>
Tested-by: Paul Moore <paul@paul-moore.com>
Tested-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: samanthakumar <samanthakumar@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for your net tree,
they are:

1) Fix incorrect timestamp in nfnetlink_queue introduced when addressing
   y2038 safe timestamp, from Florian Westphal.

2) Get rid of leftover conntrack definition from the previous merge
   window, oneliner from Florian.

3) Make nf_queue handler pernet to resolve race on dereferencing the
   hook state structure with netns removal, from Eric Biederman.

4) Ensure clean exit on unregistered helper ports, from Taehee Yoo.

5) Restore FLOWI_FLAG_KNOWN_NH in nf_dup_ipv6. This got lost while
   generalizing xt_TEE to add packet duplication support in nf_tables,
   from Paolo Abeni.

6) Insufficient netlink NFTA_SET_TABLE attribute check in
   nf_tables_getset(), from Phil Turnbull.

7) Reject helper registration on duplicated ports via modparams.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

The Kconfig options I added to work around broken compilation ended
up screwing up things more, as I used the wrong symbol to control
compilation of the file, resulting in IPv6 fou support to never be built
into the kernel.

Changing CONFIG_NET_FOU_IPV6_TUNNELS to CONFIG_IPV6_FOU fixes that
problem, I had renamed the symbol in one location but not the other,
and as the file is never being used by other kernel code, this did not
lead to a build failure that I would have caught.

After that fix, another issue with the same patch becomes obvious, as we
'select INET6_TUNNEL', which is related to IPV6_TUNNEL, but not the same,
and this can still cause the original build failure when IPV6_TUNNEL is
not built-in but IPV6_FOU is. The fix is equally trivial, we just need
to select the right symbol.

I have successfully build 350 randconfig kernels with this patch
and verified that the driver is now being built.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Valentin Rothberg <valentinrothberg@gmail.com>
Fixes: fabb13db448e ("fou: add Kconfig options for IPv6 support")
Signed-off-by: David S. Miller <davem@davemloft.net>

With the commit 48e8aa6e3137 ("ipv6: Set FLOWI_FLAG_KNOWN_NH at
flowi6_flags") ip6_pol_route() callers were asked to to set the
FLOWI_FLAG_KNOWN_NH properly and xt_TEE was updated accordingly,
but with the later refactor in commit bbde9fc1824a ("netfilter:
factor out packet duplication for IPv4/IPv6") the flowi6_flags
update was lost.
This commit re-add it just before the routing decision.

Fixes: bbde9fc1824a ("netfilter: factor out packet duplication for IPv4/IPv6")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

A previous patch added the fou6.ko module, but that failed to link
in a couple of configurations:

net/built-in.o: In function `ip6_tnl_encap_add_fou_ops':
net/ipv6/fou6.c:88: undefined reference to `ip6_tnl_encap_add_ops'
net/ipv6/fou6.c:94: undefined reference to `ip6_tnl_encap_add_ops'
net/ipv6/fou6.c:97: undefined reference to `ip6_tnl_encap_del_ops'
net/built-in.o: In function `ip6_tnl_encap_del_fou_ops':
net/ipv6/fou6.c:106: undefined reference to `ip6_tnl_encap_del_ops'
net/ipv6/fou6.c:107: undefined reference to `ip6_tnl_encap_del_ops'

If CONFIG_IPV6=m, ip6_tnl_encap_add_ops/ip6_tnl_encap_del_ops
are in a module, but fou6.c can still be built-in, and that
obviously fails to link.

Also, if CONFIG_IPV6=y, but CONFIG_IPV6_TUNNEL=m or
CONFIG_IPV6_TUNNEL=n, the same problem happens for a different
reason.

This adds two new silent Kconfig symbols to work around both
problems:

- CONFIG_IPV6_FOU is now always set to 'm' if either CONFIG_NET_FOU=m
  or CONFIG_IPV6=m
- CONFIG_IPV6_FOU_TUNNEL is set implicitly when IPV6_FOU is enabled
  and NET_FOU_IP_TUNNELS is also turned out, and it will ensure
  that CONFIG_IPV6_TUNNEL is also available.

The options could be made user-visible as well, to give additional
room for configuration, but it seems easier not to bother users
with more choice here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: aa3463d65e7b ("fou: Add encap ops for IPv6 tunnels")
Signed-off-by: David S. Miller <davem@davemloft.net>

In gre6 xmit path, we are sending a GRE packet, so set fl6 proto
to IPPROTO_GRE properly.

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When creat an ip6gretap interface with an unreachable route,
the MTU is about 14 bytes larger than what was needed.

If the remote address is reachable:
ping6 2001:0:130::1 -c 2
PING 2001:0:130::1(2001:0:130::1) 56 data bytes
64 bytes from 2001:0:130::1: icmp_seq=1 ttl=64 time=1.46 ms
64 bytes from 2001:0:130::1: icmp_seq=2 ttl=64 time=81.1 ms

Signed-off-by: David S. Miller <davem@davemloft.net>