Revert 931731123a
We can't elide the skb_set_owner_w() here because things like certain
netfilter targets (such as owner MATCH) need a socket to be set on the
SKB for correct operation.
Thanks to Jan Engelhardt and other netfilter list members for
pointing this out.
Signed-off-by: David S. Miller <davem@davemloft.net>
The patch "Replace CHECKSUM_HW by CHECKSUM_PARTIAL/CHECKSUM_COMPLETE"
changed to unconditional copying of ip_summed field from collapsed
skb. This patch reverts this change.
The majority of substantial work including heavy testing
and diagnosing by: Michael Tokarev <mjt@tls.msk.ru>
Possible reasons pointed by: Herbert Xu and Patrick McHardy.
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Throughout the TCP/DCCP (and tunnelling) code, it often happens that the
return code of a transmit function needs to be tested against NET_XMIT_CN
which is a value that does not indicate a strict error condition.
This patch uses a macro for these recurring situations which is consistent
with the already existing macro net_xmit_errno, saving on duplicated code.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
The data itself is already charged to the SKB, doing
the skb_set_owner_w() just generates a lot of noise and
extra atomics we don't really need.
Lmbench improvements on lat_tcp are minimal:
before:
TCP latency using localhost: 23.2701 microseconds
TCP latency using localhost: 23.1994 microseconds
TCP latency using localhost: 23.2257 microseconds
after:
TCP latency using localhost: 22.8380 microseconds
TCP latency using localhost: 22.9465 microseconds
TCP latency using localhost: 22.8462 microseconds
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch limits the amount of time you will defer sending a TSO segment
to less than two clock ticks, or the time between two acks, whichever is
longer.
On slow links, deferring causes significant bursts. See attached plots,
which show RTT through a 1 Mbps link with a 100 ms RTT and ~100 ms queue
for (a) non-TSO, (b) currnet TSO, and (c) patched TSO. This burstiness
causes significant jitter, tends to overflow queues early (bad for short
queues), and makes delay-based congestion control more difficult.
Deferring by a couple clock ticks I believe will have a relatively small
impact on performance.
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change net/core, ipv4 and ipv6 sysctl variables to __read_mostly.
Couldn't actually measure any performance increase while testing (.3%
I consider noise), but seems like the right thing to do.
Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace CHECKSUM_HW by CHECKSUM_PARTIAL (for outgoing packets, whose
checksum still needs to be completed) and CHECKSUM_COMPLETE (for
incoming packets, device supplied full checksum).
Patch originally from Herbert Xu, updated by myself for 2.6.18-rc3.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This small change allows for easy per-route workarounds for broken hosts or
middleboxes that are not compliant with TCP standards for window scaling.
Rather than having to turn off window scaling globally. This patch allows
reducing or disabling window scaling if window clamp is present.
Example: Mark Lord reported a problem with 2.6.17 kernel being unable to
access http://www.everymac.com
# ip route add 216.145.246.23/32 via 10.8.0.1 window 65535
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch generalises the TSO-specific bits from sk_setup_caps by adding
the sk_gso_type member to struct sock. This makes sk_setup_caps generic
so that it can be used by TCPv6 or UFO.
The only catch is that whoever uses this must provide a GSO implementation
for their protocol which I think is a fair deal :) For now UFO continues to
live without a GSO implementation which is OK since it doesn't use the sock
caps field at the moment.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the current TSO implementation, NETIF_F_TSO and ECN cannot be
turned on together in a TCP connection. The problem is that most
hardware that supports TSO does not handle CWR correctly if it is set
in the TSO packet. Correct handling requires CWR to be set in the
first packet only if it is set in the TSO header.
This patch adds the ability to turn on NETIF_F_TSO and ECN using
GSO if necessary to handle TSO packets with CWR set. Hardware
that handles CWR correctly can turn on NETIF_F_TSO_ECN in the dev->
features flag.
All TSO packets with CWR set will have the SKB_GSO_TCPV4_ECN set. If
the output device does not have the NETIF_F_TSO_ECN feature set, GSO
will split the packet up correctly with CWR only set in the first
segment.
With help from Herbert Xu <herbert@gondor.apana.org.au>.
Since ECN can always be enabled with TSO, the SOCK_NO_LARGESEND sock
flag is completely removed.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not
going to scale if we add any more segmentation methods (e.g., DCCP). So
let's merge them.
They were used to tell the protocol of a packet. This function has been
subsumed by the new gso_type field. This is essentially a set of netdev
feature bits (shifted by 16 bits) that are required to process a specific
skb. As such it's easy to tell whether a given device can process a GSO
skb: you just have to and the gso_type field and the netdev's features
field.
I've made gso_type a conjunction. The idea is that you have a base type
(e.g., SKB_GSO_TCPV4) that can be modified further to support new features.
For example, if we add a hardware TSO type that supports ECN, they would
declare NETIF_F_TSO | NETIF_F_TSO_ECN. All TSO packets with CWR set would
have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO
packets would be SKB_GSO_TCPV4. This means that only the CWR packets need
to be emulated in software.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
A lot of people have asked for a way to disable tcp_cwnd_restart(),
and it seems reasonable to add a sysctl to do that.
Signed-off-by: David S. Miller <davem@davemloft.net>
Trimming the head of an skb by calling skb_pull can cause the packet
to become unaligned if the length pulled is odd. Since the length is
entirely arbitrary for a FIN packet carrying data, this is actually
quite common.
Unaligned data is not the end of the world, but we should avoid it if
it's easily done. In this case it is trivial. Since we're discarding
all of the head data it doesn't matter whether we move skb->data forward
or back.
However, it is still possible to have unaligned skb->data in general.
So network drivers should be prepared to handle it instead of crashing.
This patch also adds an unlikely marking on len < headlen since partial
ACKs on head data are extremely rare in the wild. As the return value
of __pskb_trim_head is no longer ever NULL that has been removed.
Signed-off-by: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The following unlikely should be replaced by likely because the
condition happens every time unless there is a hard error to transmit
a packet.
Signed-off-by: Hua Zhong <hzhong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make sure that we get the full sizeof(struct sk_buff)
plus the data size accounted for in skb->truesize.
This will create invariants that will allow adding
assertion checks on skb->truesize.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a problem with the TSO packet trimming code. The cause of
this lies in the tcp_fragment() function.
When we allocate a fragment for a completely non-linear packet the
truesize is calculated for a payload length of zero. This means that
truesize could in fact be less than the real payload length.
When that happens the TSO packet trimming can cause truesize to become
negative. This in turn can cause sk_forward_alloc to be -n * PAGE_SIZE
which would trigger the warning.
I've copied the code DaveM used in tso_fragment which should work here.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch contains the following possible cleanups:
- make the following needlessly global function static:
- arp.c: arp_rcv()
- remove the following unused EXPORT_SYMBOL's:
- devinet.c: devinet_ioctl
- fib_frontend.c: ip_rt_ioctl
- inet_hashtables.c: inet_bind_bucket_create
- inet_hashtables.c: inet_bind_hash
- tcp_input.c: sysctl_tcp_abc
- tcp_ipv4.c: sysctl_tcp_tw_reuse
- tcp_output.c: sysctl_tcp_mtu_probing
- tcp_output.c: sysctl_tcp_base_mss
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Back in the dark ages, we had to be conservative and only allow 15-bit
window fields if the window scale option was not negotiated. Some
ancient stacks used a signed 16-bit quantity for the window field of
the TCP header and would get confused.
Those days are long gone, so we can use the full 16-bits by default
now.
There is a sysctl added so that we can still interact with such old
stacks
Signed-off-by: Rick Jones <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This moves some TCP-specific MTU probing state out of
inet_connection_sock back to tcp_sock.
Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
YOSHIFUJI Hideaki
John Heffner
David S. Miller
Jarek Poplawski
Gerrit Renker
Al Viro
Brian Haley
Patrick McHardy
Stephen Hemminger
Wei Yongjun
Herbert Xu
Michael Chan
Hua Zhong
Adrian Bunk
Rick Jones