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  1. 23 9月, 2006 2 次提交
  3. 18 9月, 2006 1 次提交
  5. 30 8月, 2006 1 次提交
  7. 05 8月, 2006 1 次提交
  9. 01 7月, 2006 1 次提交
  11. 30 6月, 2006 1 次提交
    • M
      [NET]: Add ECN support for TSO · b0da8537
      由 Michael Chan 提交于 
      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: NMichael Chan <mchan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      b0da8537
  13. 23 6月, 2006 1 次提交
    • H
      [NET]: Merge TSO/UFO fields in sk_buff · 7967168c
      由 Herbert Xu 提交于 
      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: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7967168c
  15. 18 6月, 2006 3 次提交
  17. 12 6月, 2006 1 次提交
    • A
      [TCP]: continued: reno sacked_out count fix · 79320d7e
      由 Aki M Nyrhinen 提交于 
      From: Aki M Nyrhinen <anyrhine@cs.helsinki.fi>

IMHO the current fix to the problem (in_flight underflow in reno)
is incorrect.  it treats the symptons but ignores the problem. the
problem is timing out packets other than the head packet when we
don't have sack. i try to explain (sorry if explaining the obvious).

with sack, scanning the retransmit queue for timed out packets is
fine because we know which packets in our retransmit queue have been
acked by the receiver.

without sack, we know only how many packets in our retransmit queue the
receiver has acknowledged, but no idea which packets.

think of a "typical" slow-start overshoot case, where for example
every third packet in a window get lost because a router buffer gets
full.

with sack, we check for timeouts on those every third packet (as the
rest have been sacked). the packet counting works out and if there
is no reordering, we'll retransmit exactly the packets that were 
lost.

without sack, however, we check for timeout on every packet and end up
retransmitting consecutive packets in the retransmit queue. in our
slow-start example, 2/3 of those retransmissions are unnecessary. these
unnecessary retransmissions eat the congestion window and evetually
prevent fast recovery from continuing, if enough packets were lost.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      79320d7e
  19. 17 5月, 2006 1 次提交
    • A
      [TCP]: reno sacked_out count fix · 8872d8e1
      由 Angelo P. Castellani 提交于 
      From: "Angelo P. Castellani" <angelo.castellani+lkml@gmail.com>

Using NewReno, if a sk_buff is timed out and is accounted as lost_out,
it should also be removed from the sacked_out.

This is necessary because recovery using NewReno fast retransmit could
take up to a lot RTTs and the sk_buff RTO can expire without actually
being really lost.

left_out = sacked_out + lost_out
in_flight = packets_out - left_out + retrans_out

Using NewReno without this patch, on very large network losses,
left_out becames bigger than packets_out + retrans_out (!!).

For this reason unsigned integer in_flight overflows to 2^32 - something.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      8872d8e1
  21. 15 4月, 2006 1 次提交
    • A
      [IPV4]: Possible cleanups. · 6c97e72a
      由 Adrian Bunk 提交于 
      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: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      6c97e72a
  23. 21 3月, 2006 2 次提交
  25. 10 2月, 2006 1 次提交
  27. 10 1月, 2006 1 次提交
  29. 04 1月, 2006 3 次提交
  31. 16 11月, 2005 1 次提交
  33. 11 11月, 2005 5 次提交
  35. 28 10月, 2005 1 次提交
    • H
      [TCP]: Clear stale pred_flags when snd_wnd changes · 2ad41065
      由 Herbert Xu 提交于 
      This bug is responsible for causing the infamous "Treason uncloaked"
messages that's been popping up everywhere since the printk was added.
It has usually been blamed on foreign operating systems.  However,
some of those reports implicate Linux as both systems are running
Linux or the TCP connection is going across the loopback interface.

In fact, there really is a bug in the Linux TCP header prediction code
that's been there since at least 2.1.8.  This bug was tracked down with
help from Dale Blount.

The effect of this bug ranges from harmless "Treason uncloaked"
messages to hung/aborted TCP connections.  The details of the bug
and fix is as follows.

When snd_wnd is updated, we only update pred_flags if
tcp_fast_path_check succeeds.  When it fails (for example,
when our rcvbuf is used up), we will leave pred_flags with
an out-of-date snd_wnd value.

When the out-of-date pred_flags happens to match the next incoming
packet we will again hit the fast path and use the current snd_wnd
which will be wrong.

In the case of the treason messages, it just happens that the snd_wnd
cached in pred_flags is zero while tp->snd_wnd is non-zero.  Therefore
when a zero-window packet comes in we incorrectly conclude that the
window is non-zero.

In fact if the peer continues to send us zero-window pure ACKs we
will continue making the same mistake.  It's only when the peer
transmits a zero-window packet with data attached that we get a
chance to snap out of it.  This is what triggers the treason
message at the next retransmit timeout.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
      2ad41065
  37. 30 9月, 2005 1 次提交
    • A
      [TCP]: Don't over-clamp window in tcp_clamp_window() · 09e9ec87
      由 Alexey Kuznetsov 提交于 
      From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>

Handle better the case where the sender sends full sized
frames initially, then moves to a mode where it trickles
out small amounts of data at a time.

This known problem is even mentioned in the comments
above tcp_grow_window() in tcp_input.c, specifically:

...
 * The scheme does not work when sender sends good segments opening
 * window and then starts to feed us spagetti. But it should work
 * in common situations. Otherwise, we have to rely on queue collapsing.
...

When the sender gives full sized frames, the "struct sk_buff" overhead
from each packet is small.  So we'll advertize a larger window.
If the sender moves to a mode where small segments are sent, this
ratio becomes tilted to the other extreme and we start overrunning
the socket buffer space.

tcp_clamp_window() tries to address this, but it's clamping of
tp->window_clamp is a wee bit too aggressive for this particular case.

Fix confirmed by Ion Badulescu.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      09e9ec87
  39. 15 9月, 2005 1 次提交
  41. 02 9月, 2005 1 次提交
  43. 30 8月, 2005 7 次提交
  45. 09 7月, 2005 1 次提交
  47. 06 7月, 2005 1 次提交
    • D
      [TCP]: Move to new TSO segmenting scheme. · c1b4a7e6
      由 David S. Miller 提交于 
      Make TSO segment transmit size decisions at send time not earlier.

The basic scheme is that we try to build as large a TSO frame as
possible when pulling in the user data, but the size of the TSO frame
output to the card is determined at transmit time.

This is guided by tp->xmit_size_goal.  It is always set to a multiple
of MSS and tells sendmsg/sendpage how large an SKB to try and build.

Later, tcp_write_xmit() and tcp_push_one() chop up the packet if
necessary and conditions warrant.  These routines can also decide to
"defer" in order to wait for more ACKs to arrive and thus allow larger
TSO frames to be emitted.

A general observation is that TSO elongates the pipe, thus requiring a
larger congestion window and larger buffering especially at the sender
side.  Therefore, it is important that applications 1) get a large
enough socket send buffer (this is accomplished by our dynamic send
buffer expansion code) 2) do large enough writes.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      c1b4a7e6