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  1. 01 8月, 2011 7 次提交
    • S
      dccp ccid-2: check Ack Ratio when reducing cwnd · d96a9e8d
      由 Samuel Jero 提交于 
      This patch causes CCID-2 to check the Ack Ratio after reducing the congestion
window. If the Ack Ratio is greater than the congestion window, it is
reduced. This prevents timeouts caused by an Ack Ratio larger than the
congestion window.

In this situation, we choose to set the Ack Ratio to half the congestion window
(or one if that's zero) so that if we loose one ack we don't trigger a timeout.

Signed-off-by: Samuel Jero <sj323707@ohio.edu> 
Acked-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      d96a9e8d
    • S
      dccp ccid-2: increment cwnd correctly · 0ce95dc7
      由 Samuel Jero 提交于 
      This patch fixes an issue where CCID-2 will not increase the congestion
window for numerous RTTs after an idle period, application-limited period,
or a loss once the algorithm is in Congestion Avoidance.

What happens is that, when CCID-2 is in Congestion Avoidance mode, it will
increase hc->tx_packets_acked by one for every packet and will increment cwnd
every cwnd packets. However, if there is now an idle period in the connection,
cwnd will be reduced, possibly below the slow start threshold. This will
cause the connection to go into Slow Start. However, in Slow Start CCID-2
performs this test to increment cwnd every second ack:

	++hc->tx_packets_acked == 2

Unfortunately, this will be incorrect, if cwnd previous to the idle period
was larger than 2 and if tx_packets_acked was close to cwnd. For example:
	cwnd=50  and  tx_packets_acked=45.

In this case, the current code, will increment tx_packets_acked until it
equals two, which will only be once tx_packets_acked (an unsigned 32-bit
integer) overflows.

My fix is simply to change that test for tx_packets_acked greater than or
equal to two in slow start.
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      0ce95dc7
    • S
      dccp ccid-2: prevent cwnd > Sequence Window · d346d886
      由 Samuel Jero 提交于 
      Add a check to prevent CCID-2 from increasing the cwnd greater than the
Sequence Window.

When the congestion window becomes bigger than the Sequence Window, CCID-2
will attempt to keep more data in the network than the DCCP Sequence Window
code considers possible. This results in the Sequence Window code issuing
a Sync, thereby inducing needless overhead. Further, if this occurs at the
sender, CCID-2 will never detect the problem because the Acks it receives
will indicate no losses. I have seen this cause a drop of 1/3rd in throughput
for a connection.

Also add code to adjust the Sequence Window to be about 5 times the number of
packets in the network (RFC 4340, 7.5.2) and to adjust the Ack Ratio so that
the remote Sequence Window will hold about 5 times the number of packets in
the network. This allows the congestion window to increase correctly without
being limited by the Sequence Window.
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      d346d886
    • G
      dccp ccid-2: use feature-negotiation to report Ack Ratio changes · 31daf039
      由 Gerrit Renker 提交于 
      This uses the new feature-negotiation framework to signal Ack Ratio changes,
as required by RFC 4341, sec. 6.1.2.

That raises some problems with CCID-2, which at the moment can not cope
gracefully with Ack Ratios > 1. Since these issues are not directly related
to feature negotiation, they are marked by a FIXME.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.uk>
      31daf039
    • S
      dccp: send Confirm options only once · a6444f42
      由 Samuel Jero 提交于 
      If a connection is in the OPEN state, remove feature negotiation Confirm
options from the list of options after sending them once; as such options
are NOT supposed to be retransmitted and are ONLY supposed to be sent in
response to a Change option (RFC 4340 6.2).
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
      a6444f42
    • G
      dccp: support for exchanging of NN options in established state 2/2 · 44e6fd9e
      由 Gerrit Renker 提交于 
      This patch adds the receiver side and the (fast-path) activation part for
dynamic changes of non-negotiable (NN) parameters in (PART)OPEN state.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.uk>
      44e6fd9e
    • G
      dccp: support for the exchange of NN options in established state 1/2 · d6916f87
      由 Gerrit Renker 提交于 
      In contrast to static feature negotiation at the begin of a connection, this
patch introduces support for exchange of dynamically changing options.

Such an update/exchange is necessary in at least two cases:
 * CCID-2's Ack Ratio (RFC 4341, 6.1.2) which changes during the connection;
 * Sequence Window values that, as per RFC 4340, 7.5.2, should be sent "as
   the connection progresses".

Both are non-negotiable (NN) features, which means that no new capabilities
are negotiated, but rather that changes in known parameters are brought
up-to-date at either end.

Thse characteristics are reflected by the implementation:
 * only NN options can be exchanged after connection setup;
 * an ack is scheduled directly after activation to speed up the update;
 * CCIDs may request changes to an NN feature even if a negotiation for that
   feature is already underway: this is required by CCID-2, where changes in
   cwnd necessitate Ack Ratio changes, such that the previous Ack Ratio (which
   is still being negotiated) would cause irrecoverable RTO timeouts (thanks
   to work by Samuel Jero).	   
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NSamuel Jero <sj323707@ohio.edu>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.uk>
      d6916f87
  3. 28 7月, 2011 3 次提交
    • N
      net: Audit drivers to identify those needing IFF_TX_SKB_SHARING cleared · 550fd08c
      由 Neil Horman 提交于 
      After the last patch, We are left in a state in which only drivers calling
ether_setup have IFF_TX_SKB_SHARING set (we assume that drivers touching real
hardware call ether_setup for their net_devices and don't hold any state in
their skbs.  There are a handful of drivers that violate this assumption of
course, and need to be fixed up.  This patch identifies those drivers, and marks
them as not being able to support the safe transmission of skbs by clearning the
IFF_TX_SKB_SHARING flag in priv_flags
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
CC: Karsten Keil <isdn@linux-pingi.de>
CC: "David S. Miller" <davem@davemloft.net>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: Patrick McHardy <kaber@trash.net>
CC: Krzysztof Halasa <khc@pm.waw.pl>
CC: "John W. Linville" <linville@tuxdriver.com>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Marcel Holtmann <marcel@holtmann.org>
CC: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      550fd08c
    • N
      net: add IFF_SKB_TX_SHARED flag to priv_flags · d8873315
      由 Neil Horman 提交于 
      Pktgen attempts to transmit shared skbs to net devices, which can't be used by
some drivers as they keep state information in skbs.  This patch adds a flag
marking drivers as being able to handle shared skbs in their tx path.  Drivers
are defaulted to being unable to do so, but calling ether_setup enables this
flag, as 90% of the drivers calling ether_setup touch real hardware and can
handle shared skbs.  A subsequent patch will audit drivers to ensure that the
flag is set properly
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Reported-by: NJiri Pirko <jpirko@redhat.com>
CC: Robert Olsson <robert.olsson@its.uu.se>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Alexey Dobriyan <adobriyan@gmail.com>
CC: David S. Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d8873315
    • E
      net: sock_sendmsg_nosec() is static · 894dc24c
      由 Eric Dumazet 提交于 
      Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Anton Blanchard <anton@samba.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      894dc24c
  5. 27 7月, 2011 5 次提交
  7. 26 7月, 2011 6 次提交
  9. 24 7月, 2011 3 次提交
  11. 23 7月, 2011 15 次提交
  13. 22 7月, 2011 1 次提交