Commit graph

234 commits

Author SHA1 Message Date
Eric Dumazet
de213e5eed tcp: tcp_synack_options() fix
Commit 33ad798c92 (tcp: options clean up) introduced a problem
if MD5+SACK+timestamps were used in initial SYN message.

Some stacks (old linux for example) try to negotiate MD5+SACK+TSTAMP
sessions, but since 40 bytes of tcp options space are not enough to
store all the bits needed, we chose to disable timestamps in this case.

We send a SYN-ACK _without_ timestamp option, but socket has timestamps
enabled and all further outgoing messages contain a TS block, all with
the initial timestamp of the remote peer.

Fix is to really disable timestamps option for the whole session.

Reported-by: Bijay Singh <Bijay.Singh@guavus.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 22:35:36 -07:00
Eric Dumazet
a465419b1f net: Introduce sk_route_nocaps
TCP-MD5 sessions have intermittent failures, when route cache is
invalidated. ip_queue_xmit() has to find a new route, calls
sk_setup_caps(sk, &rt->u.dst), destroying the 

sk->sk_route_caps &= ~NETIF_F_GSO_MASK

that MD5 desperately try to make all over its way (from
tcp_transmit_skb() for example)

So we send few bad packets, and everything is fine when
tcp_transmit_skb() is called again for this socket.

Since ip_queue_xmit() is at a lower level than TCP-MD5, I chose to use a
socket field, sk_route_nocaps, containing bits to mask on sk_route_caps.

Reported-by: Bhaskar Dutta <bhaskie@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-16 00:36:33 -07:00
Tom Herbert
aa2ea0586d tcp: fix outsegs stat for TSO segments
Account for TSO segments of an skb in TCP_MIB_OUTSEGS counter.  Without
doing this, the counter can be off by orders of magnitude from the
actual number of segments sent.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-22 16:00:00 -07:00
Eric Dumazet
0eae88f31c net: Fix various endianness glitches
Sparse can help us find endianness bugs, but we need to make some
cleanups to be able to more easily spot real bugs.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-20 19:06:52 -07:00
Shan Wei
4e15ed4d93 net: replace ipfragok with skb->local_df
As Herbert Xu said: we should be able to simply replace ipfragok
with skb->local_df. commit f88037(sctp: Drop ipfargok in sctp_xmit function)
has droped ipfragok and set local_df value properly.

The patch kills the ipfragok parameter of .queue_xmit().

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-15 23:36:37 -07:00
David S. Miller
2e8e18ef52 tcp: Set CHECKSUM_UNNECESSARY in tcp_init_nondata_skb
Back in commit 04a0551c87
("loopback: Drop obsolete ip_summed setting") we stopped
setting CHECKSUM_UNNECESSARY in the loopback xmit.

This is because such a setting was a lie since it implies that the
checksum field of the packet is properly filled in.

Instead what happens normally is that CHECKSUM_PARTIAL is set and
skb->csum is calculated as needed.

But this was only happening for TCP data packets (via the
skb->ip_summed assignment done in tcp_sendmsg()).  It doesn't
happen for non-data packets like ACKs etc.

Fix this by setting skb->ip_summed in the common non-data packet
constructor.  It already is setting skb->csum to zero.

But this reminds us that we still have things like ip_output.c's
ip_dev_loopback_xmit() which sets skb->ip_summed to the value
CHECKSUM_UNNECESSARY, which Herbert's patch teaches us is not
valid.  So we'll have to address that at some point too.

Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-11 15:29:13 -07:00
Herbert Xu
bb29624614 inet: Remove unused send_check length argument
inet: Remove unused send_check length argument

This patch removes the unused length argument from the send_check
function in struct inet_connection_sock_af_ops.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Yinghai <yinghai.lu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-11 15:29:09 -07:00
Tejun Heo
5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Eric Dumazet
28b2774a0d tcp: Fix tcp_make_synack()
Commit 4957faad (TCPCT part 1g: Responder Cookie => Initiator), part
of TCP_COOKIE_TRANSACTION implementation, forgot to correctly size
synack skb in case user data must be included.

Many thanks to Mika Pentillä for spotting this error.

Reported-by: Penttillä Mika <mika.penttila@ixonos.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-03-08 11:32:01 -08:00
laurent chavey
31d12926e3 net: Add rtnetlink init_rcvwnd to set the TCP initial receive window
Add rtnetlink init_rcvwnd to set the TCP initial receive window size
advertised by passive and active TCP connections.
The current Linux TCP implementation limits the advertised TCP initial
receive window to the one prescribed by slow start. For short lived
TCP connections used for transaction type of traffic (i.e. http
requests), bounding the advertised TCP initial receive window results
in increased latency to complete the transaction.
Support for setting initial congestion window is already supported
using rtnetlink init_cwnd, but the feature is useless without the
ability to set a larger TCP initial receive window.
The rtnetlink init_rcvwnd allows increasing the TCP initial receive
window, allowing TCP connection to advertise larger TCP receive window
than the ones bounded by slow start.

Signed-off-by: Laurent Chavey <chavey@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-23 14:13:30 -08:00
Krishna Kumar
12d50c46dc tcp: Remove check in __tcp_push_pending_frames
tcp_push checks tcp_send_head and calls __tcp_push_pending_frames,
which again checks tcp_send_head, and this unnecessary check is
done for every other caller of __tcp_push_pending_frames.

Remove tcp_send_head check in __tcp_push_pending_frames and add
the check to tcp_push_pending_frames. Other functions call
__tcp_push_pending_frames only when tcp_send_head would evaluate
to true.

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-23 14:13:28 -08:00
David S. Miller
bb5b7c1126 tcp: Revert per-route SACK/DSACK/TIMESTAMP changes.
It creates a regression, triggering badness for SYN_RECV
sockets, for example:

[19148.022102] Badness at net/ipv4/inet_connection_sock.c:293
[19148.022570] NIP: c02a0914 LR: c02a0904 CTR: 00000000
[19148.023035] REGS: eeecbd30 TRAP: 0700   Not tainted  (2.6.32)
[19148.023496] MSR: 00029032 <EE,ME,CE,IR,DR>  CR: 24002442  XER: 00000000
[19148.024012] TASK = eee9a820[1756] 'privoxy' THREAD: eeeca000

This is likely caused by the change in the 'estab' parameter
passed to tcp_parse_options() when invoked by the functions
in net/ipv4/tcp_minisocks.c

But even if that is fixed, the ->conn_request() changes made in
this patch series is fundamentally wrong.  They try to use the
listening socket's 'dst' to probe the route settings.  The
listening socket doesn't even have a route, and you can't
get the right route (the child request one) until much later
after we setup all of the state, and it must be done by hand.

This stuff really isn't ready, so the best thing to do is a
full revert.  This reverts the following commits:

f55017a93f
022c3f7d82
1aba721eba
cda42ebd67
345cda2fd6
dc343475ed
05eaade278
6a2a2d6bf8

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-15 20:56:42 -08:00
David S. Miller
e6b09ccada tcp: sysctl_tcp_cookie_size needs to be exported to modules.
Otherwise:

ERROR: "sysctl_tcp_cookie_size" [net/ipv6/ipv6.ko] undefined!
make[1]: *** [__modpost] Error 1

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:18:58 -08:00
David S. Miller
f9a2e69e8b tcp: Fix warning on 64-bit.
net/ipv4/tcp_output.c: In function ‘tcp_make_synack’:
net/ipv4/tcp_output.c:2488: warning: cast from pointer to integer of different size

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:12:04 -08:00
William Allen Simpson
4957faade1 TCPCT part 1g: Responder Cookie => Initiator
Parse incoming TCP_COOKIE option(s).

Calculate <SYN,ACK> TCP_COOKIE option.

Send optional <SYN,ACK> data.

This is a significantly revised implementation of an earlier (year-old)
patch that no longer applies cleanly, with permission of the original
author (Adam Langley):

    http://thread.gmane.org/gmane.linux.network/102586

Requires:
   TCPCT part 1a: add request_values parameter for sending SYNACK
   TCPCT part 1b: generate Responder Cookie secret
   TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS
   TCPCT part 1d: define TCP cookie option, extend existing struct's
   TCPCT part 1e: implement socket option TCP_COOKIE_TRANSACTIONS
   TCPCT part 1f: Initiator Cookie => Responder

Signed-off-by: William.Allen.Simpson@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:07:26 -08:00
William Allen Simpson
bd0388ae77 TCPCT part 1f: Initiator Cookie => Responder
Calculate and format <SYN> TCP_COOKIE option.

This is a significantly revised implementation of an earlier (year-old)
patch that no longer applies cleanly, with permission of the original
author (Adam Langley):

    http://thread.gmane.org/gmane.linux.network/102586

Requires:
   TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS
   TCPCT part 1d: define TCP cookie option, extend existing struct's

Signed-off-by: William.Allen.Simpson@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:07:26 -08:00
William Allen Simpson
519855c508 TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS
Define sysctl (tcp_cookie_size) to turn on and off the cookie option
default globally, instead of a compiled configuration option.

Define per socket option (TCP_COOKIE_TRANSACTIONS) for setting constant
data values, retrieving variable cookie values, and other facilities.

Move inline tcp_clear_options() unchanged from net/tcp.h to linux/tcp.h,
near its corresponding struct tcp_options_received (prior to changes).

This is a straightforward re-implementation of an earlier (year-old)
patch that no longer applies cleanly, with permission of the original
author (Adam Langley):

    http://thread.gmane.org/gmane.linux.network/102586

These functions will also be used in subsequent patches that implement
additional features.

Requires:
   net: TCP_MSS_DEFAULT, TCP_MSS_DESIRED

Signed-off-by: William.Allen.Simpson@gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:07:24 -08:00
William Allen Simpson
e6b4d11367 TCPCT part 1a: add request_values parameter for sending SYNACK
Add optional function parameters associated with sending SYNACK.
These parameters are not needed after sending SYNACK, and are not
used for retransmission.  Avoids extending struct tcp_request_sock,
and avoids allocating kernel memory.

Also affects DCCP as it uses common struct request_sock_ops,
but this parameter is currently reserved for future use.

Signed-off-by: William.Allen.Simpson@gmail.com
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-02 22:07:23 -08:00
Joe Perches
9d4fb27db9 net/ipv4: Move && and || to end of previous line
On Sun, 2009-11-22 at 16:31 -0800, David Miller wrote:
> It should be of the form:
> 	if (x &&
> 	    y)
> 
> or:
> 	if (x && y)
> 
> Fix patches, rather than complaints, for existing cases where things
> do not follow this pattern are certainly welcome.

Also collapsed some multiple tabs to single space.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-23 10:41:23 -08:00
Gilad Ben-Yossef
345cda2fd6 Allow to turn off TCP window scale opt per route
Add and use no window scale bit in the features field.

Note that this is not the same as setting a window scale of 0
as would happen with window limit on route.

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
Sigend-off-by: Ori Finkelman <ori@comsleep.com>
Sigend-off-by: Yony Amit <yony@comsleep.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-29 01:28:47 -07:00
Gilad Ben-Yossef
cda42ebd67 Allow disabling TCP timestamp options per route
Implement querying and acting upon the no timestamp bit in the feature
field.

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
Sigend-off-by: Ori Finkelman <ori@comsleep.com>
Sigend-off-by: Yony Amit <yony@comsleep.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-29 01:28:45 -07:00
Gilad Ben-Yossef
1aba721eba Add the no SACK route option feature
Implement querying and acting upon the no sack bit in the features
field.

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
Sigend-off-by: Ori Finkelman <ori@comsleep.com>
Sigend-off-by: Yony Amit <yony@comsleep.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-29 01:28:44 -07:00
Eric Dumazet
c720c7e838 inet: rename some inet_sock fields
In order to have better cache layouts of struct sock (separate zones
for rx/tx paths), we need this preliminary patch.

Goal is to transfert fields used at lookup time in the first
read-mostly cache line (inside struct sock_common) and move sk_refcnt
to a separate cache line (only written by rx path)

This patch adds inet_ prefix to daddr, rcv_saddr, dport, num, saddr,
sport and id fields. This allows a future patch to define these
fields as macros, like sk_refcnt, without name clashes.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-18 18:52:53 -07:00
Ori Finkelman
89e95a613c IPv4 TCP fails to send window scale option when window scale is zero
Acknowledge TCP window scale support by inserting the proper option in SYN/ACK
and SYN headers even if our window scale is zero.

This fixes the following observed behavior:

1. Client sends a SYN with TCP window scaling option and non zero window scale
value to a Linux box.
2. Linux box notes large receive window from client.
3. Linux decides on a zero value of window scale for its part.
4. Due to compare against requested window scale size option, Linux does not to
 send windows scale TCP option header on SYN/ACK at all.

With the following result:

Client box thinks TCP window scaling is not supported, since SYN/ACK had no
TCP window scale option, while Linux thinks that TCP window scaling is
supported (and scale might be non zero), since SYN had  TCP window scale
option and we have a mismatched idea between the client and server
regarding window sizes.

Probably it also fixes up the following bug (not observed in practice):

1. Linux box opens TCP connection to some server.
2. Linux decides on zero value of window scale.
3. Due to compare against computed window scale size option, Linux does
not to set windows scale TCP  option header on SYN.

With the expected result that the server OS does not use window scale option
due to not receiving such an option in the SYN headers, leading to suboptimal
performance.

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
Signed-off-by: Ori Finkelman <ori@comsleep.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-01 15:14:51 -07:00
Wu Fengguang
aa1330766c tcp: replace hard coded GFP_KERNEL with sk_allocation
This fixed a lockdep warning which appeared when doing stress
memory tests over NFS:

	inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.

	page reclaim => nfs_writepage => tcp_sendmsg => lock sk_lock

	mount_root => nfs_root_data => tcp_close => lock sk_lock =>
			tcp_send_fin => alloc_skb_fclone => page reclaim

David raised a concern that if the allocation fails in tcp_send_fin(), and it's
GFP_ATOMIC, we are going to yield() (which sleeps) and loop endlessly waiting
for the allocation to succeed.

But fact is, the original GFP_KERNEL also sleeps. GFP_ATOMIC+yield() looks
weird, but it is no worse the implicit sleep inside GFP_KERNEL. Both could
loop endlessly under memory pressure.

CC: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
CC: David S. Miller <davem@davemloft.net>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-09-02 23:45:45 -07:00
David S. Miller
74d154189d Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/wireless/iwmc3200wifi/netdev.c
	net/wireless/scan.c
2009-07-23 19:03:51 -07:00
Andi Kleen
67edfef786 TCP: Add comments to (near) all functions in tcp_output.c v3
While looking for something else I spent some time adding
one liner comments to the tcp_output.c functions that
didn't have any. That makes the comments more consistent.

I hope I documented everything right.

No code changes.

v2: Incorporated feedback from Ilpo.
v3: Change style of one liner comments, add a few more comments.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-23 18:01:12 -07:00
John Dykstra
e3afe7b75e tcp: Fix MD5 signature checking on IPv4 mapped sockets
Fix MD5 signature checking so that an IPv4 active open
to an IPv6 socket can succeed.  In particular, use the
correct address family's signature generation function
for the SYN/ACK.

Reported-by:   Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: John Dykstra <john.dykstra1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-07-20 07:49:07 -07:00
Herbert Xu
8e5b9dda99 tcp: Stop non-TSO packets morphing into TSO
If a socket starts out on a non-TSO route, and then switches to
a TSO route, then the tail on the tx queue can morph into a TSO
packet, causing mischief because the rest of the stack does not
expect a partially linear TSO packet.

This patch fixes this by ensuring that skb->ip_summed is set to
CHECKSUM_PARTIAL before declaring a packet as TSO.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-29 19:41:39 -07:00
Eric Dumazet
adf30907d6 net: skb->dst accessors
Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-03 02:51:04 -07:00
Ilpo Järvinen
255cac91c3 tcp: extend ECN sysctl to allow server-side only ECN
This should be very safe compared with full enabled, so I see
no reason why it shouldn't be done right away. As ECN can only
be negotiated if the SYN sending party is also supporting it,
somebody in the loop probably knows what he/she is doing. If
SYN does not ask for ECN, the server side SYN-ACK is identical
to what it is without ECN. Thus it's quite safe.

The chosen value is safe w.r.t to existing configs which
choose to currently set manually either 0 or 1 but
silently upgrades those who have not explicitly requested
ECN off.

Whether to just enable both sides comes up time to time but
unless that gets done now we can at least make the servers
aware of ECN already. As there are some known problems to occur
if ECN is enabled, it's currently questionable whether there's
any real gain from enabling clients as servers mostly won't
support it anyway (so we'd hit just the negative sides). After
enabling the servers and getting that deployed, the client end
enable really has some potential gain too.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-05-04 11:07:36 -07:00
Ilpo Järvinen
52cf3cc8ac tcp: fix mid-wq adjustment helper
Just noticed while doing some new work that the recent
mid-wq adjustment logic will misbehave when FACK is not
in use (happens either due sysctl'ed off or auto-detected
reordering) because I forgot the relevant TCPCB tagbit.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-04-20 02:15:00 -07:00
Ilpo Järvinen
9eb9362e56 tcp: miscounts due to tcp_fragment pcount reset
It seems that trivial reset of pcount to one was not sufficient
in tcp_retransmit_skb. Multiple counters experience a positive
miscount when skb's pcount gets lowered without the necessary
adjustments (depending on skb's sacked bits which exactly), at
worst a packets_out miscount can crash at RTO if the write queue
is empty!

Triggering this requires mss change, so bidir tcp or mtu probe or
like.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Tested-by: Uwe Bugla <uwe.bugla@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-04-02 16:31:45 -07:00
Ilpo Järvinen
797108d134 tcp: add helper for counter tweaking due mid-wq change
We need full-scale adjustment to fix a TCP miscount in the next
patch, so just move it into a helper and call for that from the
other places.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-04-02 16:31:44 -07:00
Ilpo Järvinen
0c54b85f28 tcp: simplify tcp_current_mss
There's very little need for most of the callsites to get
tp->xmit_goal_size updated. That will cost us divide as is,
so slice the function in two. Also, the only users of the
tp->xmit_goal_size are directly behind tcp_current_mss(),
so there's no need to store that variable into tcp_sock
at all! The drop of xmit_goal_size currently leaves 16-bit
hole and some reorganization would again be necessary to
change that (but I'm aiming to fill that hole with u16
xmit_goal_size_segs to cache the results of the remaining
divide to get that tso on regression).

Bring xmit_goal_size parts into tcp.c

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-15 20:09:54 -07:00
Ilpo Järvinen
5861f8e58d tcp: remove pointless .dsack/.num_sacks code
In the pure assignment case, the earlier zeroing is
still in effect.

David S. Miller raised concerns if the ifs are there to avoid
dirtying cachelines. I came to these conclusions:

> We'll be dirty it anyway (now that I check), the first "real" statement
> in tcp_rcv_established is:
>
>       tp->rx_opt.saw_tstamp = 0;
>
> ...that'll land on the same dword. :-/
>
> I suppose the blocks are there just because they had more complexity
> inside when they had to calculate the eff_sacks too (maybe it would
> have been better to just remove them in that drop-patch so you would
> have had less head-ache :-)).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-15 20:09:51 -07:00
Hantzis Fotis
ee7537b63a tcp: tcp_init_wl / tcp_update_wl argument cleanup
The above functions from include/net/tcp.h have been defined with an
argument that they never use. The argument is 'u32 ack' which is never
used inside the function body, and thus it can be removed. The rest of
the patch involves the necessary changes to the function callers of the
above two functions.

Signed-off-by: Hantzis Fotis <xantzis@ceid.upatras.gr>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 22:42:02 -08:00
Ilpo Järvinen
9ce0146102 tcp: get rid of two unnecessary u16s in TCP skb flags copying
I guess these fields were one day 16-bit in the struct but
nowadays they're just using 8 bits anyway.

This is just a precaution, didn't result any change in my
case but who knows what all those varying gcc versions &
options do. I've been told that 16-bit is not so nice with
some cpus.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:17 -08:00
Ilpo Järvinen
cabeccbd17 tcp: kill eff_sacks "cache", the sole user can calculate itself
Also fixes insignificant bug that would cause sending of stale
SACK block (would occur in some corner cases).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:16 -08:00
Ilpo Järvinen
e6c7d08579 tcp: drop unnecessary local var in collapse
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:13 -08:00
Ilpo Järvinen
02276f3c96 tcp: fix corner case issue in segmentation during rexmitting
If cur_mss grew very recently so that the previously G/TSOed skb
now fits well into a single segment it would get send up in
parts unless we calculate # of segments again. This corner-case
could happen eg. after mtu probe completes or less than
previously sack blocks are required for the opposite direction.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:11 -08:00
Ilpo Järvinen
d3d2ae4545 tcp: Don't clear hints when tcp_fragmenting
1) We didn't remove any skbs, so no need to handle stale refs.

2) scoreboard_skb_hint is trivial, no timestamps were changed
   so no need to clear that one

3) lost_skb_hint needs tweaking similar to that of
   tcp_sacktag_one().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:10 -08:00
Ilpo Järvinen
62ad27619c tcp: deferring in middle of queue makes very little sense
If skb can be sent right away, we certainly should do that
if it's in the middle of the queue because it won't get
more data into it.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:10 -08:00
Ilpo Järvinen
ac11ba753f tcp: don't backtrack to sacked skbs
Backtracking to sacked skbs is a horrible performance killer
since the hint cannot be advanced successfully past them...
...And it's totally unnecessary too.

In theory this is 2.6.27..28 regression but I doubt anybody
can make .28 to have worse performance because of other TCP
improvements.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-03-02 03:00:08 -08:00
David S. Miller
e70049b9e7 Merge branch 'master' of /home/davem/src/GIT/linux-2.6/ 2009-02-24 03:50:29 -08:00
Herbert Xu
7691367d71 tcp: Always set urgent pointer if it's beyond snd_nxt
Our TCP stack does not set the urgent flag if the urgent pointer
does not fit in 16 bits, i.e., if it is more than 64K from the
sequence number of a packet.

This behaviour is different from the BSDs, and clearly contradicts
the purpose of urgent mode, which is to send the notification
(though not necessarily the associated data) as soon as possible.
Our current behaviour may in fact delay the urgent notification
indefinitely if the receiver window does not open up.

Simply matching BSD however may break legacy applications which
incorrectly rely on the out-of-band delivery of urgent data, and
conversely the in-band delivery of non-urgent data.

Alexey Kuznetsov suggested a safe solution of following BSD only
if the urgent pointer itself has not yet been transmitted.  This
way we guarantee that when the remote end sees the packet with
non-urgent data marked as urgent due to wrap-around we would have
advanced the urgent pointer beyond, either to the actual urgent
data or to an as-yet untransmitted packet.

The only potential downside is that applications on the remote
end may see multiple SIGURG notifications.  However, this would
occur anyway with other TCP stacks.  More importantly, the outcome
of such a duplicate notification is likely to be harmless since
the signal itself does not carry any information other than the
fact that we're in urgent mode.

Thanks to Ilpo Järvinen for fixing a critical bug in this and
Jeff Chua for reporting that bug.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-21 23:52:29 -08:00
Ilpo Järvinen
5209921cf1 tcp: remove obsoleted comment about different passes
This is obsolete since the passes got combined.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-18 17:45:44 -08:00
David S. Miller
a23f4bbd8d Revert "tcp: Always set urgent pointer if it's beyond snd_nxt"
This reverts commit 64ff3b938e.

Jeff Chua reports that it breaks rlogin for him.

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-05 15:38:31 -08:00
Herbert Xu
64ff3b938e tcp: Always set urgent pointer if it's beyond snd_nxt
Our TCP stack does not set the urgent flag if the urgent pointer
does not fit in 16 bits, i.e., if it is more than 64K from the
sequence number of a packet.

This behaviour is different from the BSDs, and clearly contradicts
the purpose of urgent mode, which is to send the notification
(though not necessarily the associated data) as soon as possible.
Our current behaviour may in fact delay the urgent notification
indefinitely if the receiver window does not open up.

Simply matching BSD however may break legacy applications which
incorrectly rely on the out-of-band delivery of urgent data, and
conversely the in-band delivery of non-urgent data.

Alexey Kuznetsov suggested a safe solution of following BSD only
if the urgent pointer itself has not yet been transmitted.  This
way we guarantee that when the remote end sees the packet with
non-urgent data marked as urgent due to wrap-around we would have
advanced the urgent pointer beyond, either to the actual urgent
data or to an as-yet untransmitted packet.

The only potential downside is that applications on the remote
end may see multiple SIGURG notifications.  However, this would
occur anyway with other TCP stacks.  More importantly, the outcome
of such a duplicate notification is likely to be harmless since
the signal itself does not carry any information other than the
fact that we're in urgent mode.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-25 17:12:58 -08:00
Ilpo Järvinen
a2acde0771 tcp: fix tso_should_defer in 64bit
Since jiffies is unsigned long, the types get expanded into
that and after long enough time the difference will therefore
always be > 1 (and that probably happens near boot as well as
iirc the first jiffies wrap is scheduler close after boot to
find out problems related to that early).

This was originally noted by Bill Fink in Dec'07 but nobody
never ended fixing it.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-05 22:56:07 -08:00