linux-toradex.git/include/linux/skbuff.h, branch v3.2.66

Revert "net: ip, ipv6: handle gso skbs in forwarding path"

2014-08-06T17:07:31+00:00

This reverts commit caa5344994778a2b4725b2d75c74430f76925e4a, which
was commit fe6cc55f3a9a053482a76f5a6b2257cee51b4663 upstream.  In 3.2,
the transport header length is not calculated in the forwarding path,
so skb_gso_network_seglen() returns an incorrect result.  We also have
problems due to the local_df flag not being set correctly.

Signed-off-by: Ben Hutchings

skbuff: add an api to orphan frags

2014-07-11T12:33:59+00:00

commit a353e0ce0fd42d8859260666d1e9b10f2abd4698 upstream.

Many places do
       if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY))
		skb_copy_ubufs(skb, gfp_mask);
to copy and invoke frag destructors if necessary.
Add an inline helper for this.

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

skb: Add inline helper for getting the skb end offset from head

2014-06-09T12:29:00+00:00

[ Upstream commit ec47ea82477404631d49b8e568c71826c9b663ac ]

With the recent changes for how we compute the skb truesize it occurs to me
we are probably going to have a lot of calls to skb_end_pointer -
skb->head.  Instead of running all over the place doing that it would make
more sense to just make it a separate inline skb_end_offset(skb) that way
we can return the correct value without having gcc having to do all the
optimization to cancel out skb->head - skb->head.

Signed-off-by: Alexander Duyck 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: ip, ipv6: handle gso skbs in forwarding path

2014-04-09T01:20:45+00:00

commit fe6cc55f3a9a053482a76f5a6b2257cee51b4663 upstream.

[ use zero netdev_feature mask to avoid backport of
  netif_skb_dev_features function ]

Marcelo Ricardo Leitner reported problems when the forwarding link path
has a lower mtu than the incoming one if the inbound interface supports GRO.

Given:
Host  R1  R2

Host sends tcp stream which is routed via R1 and R2.  R1 performs GRO.

In this case, the kernel will fail to send ICMP fragmentation needed
messages (or pkt too big for ipv6), as GSO packets currently bypass dstmtu
checks in forward path. Instead, Linux tries to send out packets exceeding
the mtu.

When locking route MTU on Host (i.e., no ipv4 DF bit set), R1 does
not fragment the packets when forwarding, and again tries to send out
packets exceeding R1-R2 link mtu.

This alters the forwarding dstmtu checks to take the individual gso
segment lengths into account.

For ipv6, we send out pkt too big error for gso if the individual
segments are too big.

For ipv4, we either send icmp fragmentation needed, or, if the DF bit
is not set, perform software segmentation and let the output path
create fragments when the packet is leaving the machine.
It is not 100% correct as the error message will contain the headers of
the GRO skb instead of the original/segmented one, but it seems to
work fine in my (limited) tests.

Eric Dumazet suggested to simply shrink mss via ->gso_size to avoid
sofware segmentation.

However it turns out that skb_segment() assumes skb nr_frags is related
to mss size so we would BUG there.  I don't want to mess with it considering
Herbert and Eric disagree on what the correct behavior should be.

Hannes Frederic Sowa notes that when we would shrink gso_size
skb_segment would then also need to deal with the case where
SKB_MAX_FRAGS would be exceeded.

This uses sofware segmentation in the forward path when we hit ipv4
non-DF packets and the outgoing link mtu is too small.  Its not perfect,
but given the lack of bug reports wrt. GRO fwd being broken this is a
rare case anyway.  Also its not like this could not be improved later
once the dust settles.

Acked-by: Herbert Xu 
Reported-by: Marcelo Ricardo Leitner 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: add and use skb_gso_transport_seglen()

2014-04-09T01:20:45+00:00

commit de960aa9ab4decc3304959f69533eef64d05d8e8 upstream.

[ no skb_gso_seglen helper in 3.4, leave tbf alone ]

This moves part of Eric Dumazets skb_gso_seglen helper from tbf sched to
skbuff core so it may be reused by upcoming ip forwarding path patch.

Signed-off-by: Florian Westphal 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

inet: fix possible memory corruption with UDP_CORK and UFO

2013-11-28T14:01:59+00:00

[ This is a simplified -stable version of a set of upstream commits. ]

This is a replacement patch only for stable which does fix the problems
handled by the following two commits in -net:

"ip_output: do skb ufo init for peeked non ufo skb as well" (e93b7d748be887cd7639b113ba7d7ef792a7efb9)
"ip6_output: do skb ufo init for peeked non ufo skb as well" (c547dbf55d5f8cf615ccc0e7265e98db27d3fb8b)

Three frames are written on a corked udp socket for which the output
netdevice has UFO enabled.  If the first and third frame are smaller than
the mtu and the second one is bigger, we enqueue the second frame with
skb_append_datato_frags without initializing the gso fields. This leads
to the third frame appended regulary and thus constructing an invalid skb.

This fixes the problem by always using skb_append_datato_frags as soon
as the first frag got enqueued to the skb without marking the packet
as SKB_GSO_UDP.

The problem with only two frames for ipv6 was fixed by "ipv6: udp
packets following an UFO enqueued packet need also be handled by UFO"
(2811ebac2521ceac84f2bdae402455baa6a7fb47).

Cc: Jiri Pirko 
Cc: Eric Dumazet 
Cc: David Miller 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings

tcp: must unclone packets before mangling them

2013-11-28T14:01:56+00:00

[ Upstream commit c52e2421f7368fd36cbe330d2cf41b10452e39a9 ]

TCP stack should make sure it owns skbs before mangling them.

We had various crashes using bnx2x, and it turned out gso_size
was cleared right before bnx2x driver was populating TC descriptor
of the _previous_ packet send. TCP stack can sometime retransmit
packets that are still in Qdisc.

Of course we could make bnx2x driver more robust (using
ACCESS_ONCE(shinfo->gso_size) for example), but the bug is TCP stack.

We have identified two points where skb_unclone() was needed.

This patch adds a WARN_ON_ONCE() to warn us if we missed another
fix of this kind.

Kudos to Neal for finding the root cause of this bug. Its visible
using small MSS.

Signed-off-by: Eric Dumazet 
Signed-off-by: Neal Cardwell 
Cc: Yuchung Cheng 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

netfilter: don't reset nf_trace in nf_reset()

2013-05-13T14:02:36+00:00

[ Upstream commit 124dff01afbdbff251f0385beca84ba1b9adda68 ]

Commit 130549fe ("netfilter: reset nf_trace in nf_reset") added code
to reset nf_trace in nf_reset(). This is wrong and unnecessary.

nf_reset() is used in the following cases:

- when passing packets up the the socket layer, at which point we want to
  release all netfilter references that might keep modules pinned while
  the packet is queued. nf_trace doesn't matter anymore at this point.

- when encapsulating or decapsulating IPsec packets. We want to continue
  tracing these packets after IPsec processing.

- when passing packets through virtual network devices. Only devices on
  that encapsulate in IPv4/v6 matter since otherwise nf_trace is not
  used anymore. Its not entirely clear whether those packets should
  be traced after that, however we've always done that.

- when passing packets through virtual network devices that make the
  packet cross network namespace boundaries. This is the only cases
  where we clearly want to reset nf_trace and is also what the
  original patch intended to fix.

Add a new function nf_reset_trace() and use it in dev_forward_skb() to
fix this properly.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

tcp: fix skb_availroom()

2013-03-27T02:41:06+00:00

[ Upstream commit 16fad69cfe4adbbfa813de516757b87bcae36d93 ]

Chrome OS team reported a crash on a Pixel ChromeBook in TCP stack :

https://code.google.com/p/chromium/issues/detail?id=182056

commit a21d45726acac (tcp: avoid order-1 allocations on wifi and tx
path) did a poor choice adding an 'avail_size' field to skb, while
what we really needed was a 'reserved_tailroom' one.

It would have avoided commit 22b4a4f22da (tcp: fix retransmit of
partially acked frames) and this commit.

Crash occurs because skb_split() is not aware of the 'avail_size'
management (and should not be aware)

Signed-off-by: Eric Dumazet 
Reported-by: Mukesh Agrawal 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

net: remove skb_orphan_try()

2012-07-25T03:11:40+00:00

commit 62b1a8ab9b3660bb820d8dfe23148ed6cda38574 upstream.

Orphaning skb in dev_hard_start_xmit() makes bonding behavior
unfriendly for applications sending big UDP bursts : Once packets
pass the bonding device and come to real device, they might hit a full
qdisc and be dropped. Without orphaning, the sender is automatically
throttled because sk->sk_wmemalloc reaches sk->sk_sndbuf (assuming
sk_sndbuf is not too big)

We could try to defer the orphaning adding another test in
dev_hard_start_xmit(), but all this seems of little gain,
now that BQL tends to make packets more likely to be parked
in Qdisc queues instead of NIC TX ring, in cases where performance
matters.

Reverts commits :
fc6055a5ba31 net: Introduce skb_orphan_try()
87fd308cfc6b net: skb_tx_hash() fix relative to skb_orphan_try()
and removes SKBTX_DRV_NEEDS_SK_REF flag

Reported-and-bisected-by: Jean-Michel Hautbois 
Signed-off-by: Eric Dumazet 
Tested-by: Oliver Hartkopp 
Acked-by: Oliver Hartkopp 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Adjust context
 - SKBTX_WIFI_STATUS is not defined]
Signed-off-by: Ben Hutchings