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  1. 26 4月, 2007 9 次提交
  3. 09 2月, 2007 1 次提交
  5. 05 1月, 2007 1 次提交
  7. 23 12月, 2006 1 次提交
    • G
      [TCP]: Fix ambiguity in the `before' relation. · 9a036b9c
      由 Gerrit Renker 提交于 
      While looking at DCCP sequence numbers, I stumbled over a problem with
the following definition of before in tcp.h:

static inline int before(__u32 seq1, __u32 seq2)
{
        return (__s32)(seq1-seq2) < 0;
}

Problem: This definition suffers from an an ambiguity, i.e. always

           before(a, (a + 2^31) % 2^32)) = 1
           before((a + 2^31) % 2^32), a) = 1

         In text: when the difference between a and b amounts to 2^31,
         a is always considered `before' b, the function can not decide.
         The reason is that implicitly 0 is `before' 1 ... 2^31-1 ... 2^31

Solution: There is a simple fix, by defining before in such a way that
          0 is no longer `before' 2^31, i.e. 0 `before' 1 ... 2^31-1
          By not using the middle between 0 and 2^32, before can be made
          unambiguous.
          This is achieved by testing whether seq2-seq1 > 0 (using signed
          32-bit arithmetic).

I attach a patch to codify this. Also the `after' relation is basically
a redefinition of `before', it is now defined as a macro after before.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      9a036b9c
  9. 03 12月, 2006 7 次提交
  11. 03 8月, 2006 1 次提交
    • W
      [TCP]: SNMPv2 tcpAttemptFails counter error · 3687b1dc
      由 Wei Yongjun 提交于 
      Refer to RFC2012, tcpAttemptFails is defined as following:
  tcpAttemptFails OBJECT-TYPE
      SYNTAX      Counter32
      MAX-ACCESS  read-only
      STATUS      current
      DESCRIPTION
              "The number of times TCP connections have made a direct
              transition to the CLOSED state from either the SYN-SENT
              state or the SYN-RCVD state, plus the number of times TCP
              connections have made a direct transition to the LISTEN
              state from the SYN-RCVD state."
      ::= { tcp 7 }

When I lookup into RFC793, I found that the state change should occured
under following condition:
  1. SYN-SENT -> CLOSED
     a) Received ACK,RST segment when SYN-SENT state.

  2. SYN-RCVD -> CLOSED
     b) Received SYN segment when SYN-RCVD state(came from LISTEN).
     c) Received RST segment when SYN-RCVD state(came from SYN-SENT).
     d) Received SYN segment when SYN-RCVD state(came from SYN-SENT).

  3. SYN-RCVD -> LISTEN
     e) Received RST segment when SYN-RCVD state(came from LISTEN).

In my test, those direct state transition can not be counted to
tcpAttemptFails.
Signed-off-by: NWei Yongjun <yjwei@nanjing-fnst.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      3687b1dc
  13. 09 7月, 2006 1 次提交
  15. 01 7月, 2006 1 次提交
  17. 30 6月, 2006 1 次提交
    • H
      [NET]: Added GSO header verification · 576a30eb
      由 Herbert Xu 提交于 
      When GSO packets come from an untrusted source (e.g., a Xen guest domain),
we need to verify the header integrity before passing it to the hardware.

Since the first step in GSO is to verify the header, we can reuse that
code by adding a new bit to gso_type: SKB_GSO_DODGY.  Packets with this
bit set can only be fed directly to devices with the corresponding bit
NETIF_F_GSO_ROBUST.  If the device doesn't have that bit, then the skb
is fed to the GSO engine which will allow the packet to be sent to the
hardware if it passes the header check.

This patch changes the sg flag to a full features flag.  The same method
can be used to implement TSO ECN support.  We simply have to mark packets
with CWR set with SKB_GSO_ECN so that only hardware with a corresponding
NETIF_F_TSO_ECN can accept them.  The GSO engine can either fully segment
the packet, or segment the first MTU and pass the rest to the hardware for
further segmentation.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      576a30eb
  19. 23 6月, 2006 2 次提交
    • H
      [NET]: Add software TSOv4 · f4c50d99
      由 Herbert Xu 提交于 
      This patch adds the GSO implementation for IPv4 TCP.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      f4c50d99
    • 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
  21. 18 6月, 2006 5 次提交
  23. 26 4月, 2006 1 次提交
  25. 31 3月, 2006 1 次提交
  27. 21 3月, 2006 3 次提交
  29. 04 1月, 2006 4 次提交
  31. 16 11月, 2005 1 次提交