[PATCH 0/2] Disable forwarding of LRO skbs [2nd try]

[PATCH 0/2] Disable forwarding of LRO skbs [2nd try]

[Ben Hutchings]

Large Receive Offload (LRO) destroys packet headers that should be
preserved when forwarding.  Currently it also triggers a BUG() or WARN()
in skb_gso_segment().  We should disable it wherever forwarding is
enabled, and discard LRO skbs with a warning if it is turned back on.

Since the previous version of these patches, I have:
- Tightened the test for LRO'd skbs, so it should not catch skbs from
  VM guests that want GSO
- Made the test an inline function, with the warning a separate extern
  function
- Rebased against net-next-2.6

Ben.

Ben Hutchings (2):
  net: Disable LRO on devices that are forwarding
  net: Discard and warn about LRO'd skbs received for forwarding

 include/linux/netdevice.h |    1 +
 include/linux/skbuff.h    |   14 ++++++++++++++
 net/bridge/br_forward.c   |    2 +-
 net/bridge/br_if.c        |    1 +
 net/core/dev.c            |   24 ++++++++++++++++++++++++
 net/core/skbuff.c         |    8 ++++++++
 net/ipv4/devinet.c        |   21 ++++++++++++++++-----
 net/ipv4/ip_forward.c     |    3 +++
 net/ipv6/addrconf.c       |    6 ++++++
 net/ipv6/ip6_output.c     |    3 +++
 10 files changed, 77 insertions(+), 6 deletions(-)

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.

[PATCH 0/2] Disable forwarding of LRO skbs [2nd try]

[Ben Hutchings]

[Re-sent with the correct Message-ID, previously eaten by mutt.]

Large Receive Offload (LRO) destroys packet headers that should be
preserved when forwarding.  Currently it also triggers a BUG() or WARN()
in skb_gso_segment().  We should disable it wherever forwarding is
enabled, and discard LRO skbs with a warning if it is turned back on.

Since the previous version of these patches, I have:
- Tightened the test for LRO'd skbs, so it should not catch skbs from
  VM guests that want GSO
- Made the test an inline function, with the warning a separate extern
  function
- Rebased against net-next-2.6

Ben.

Ben Hutchings (2):
  net: Disable LRO on devices that are forwarding
  net: Discard and warn about LRO'd skbs received for forwarding

 include/linux/netdevice.h |    1 +
 include/linux/skbuff.h    |   14 ++++++++++++++
 net/bridge/br_forward.c   |    2 +-
 net/bridge/br_if.c        |    1 +
 net/core/dev.c            |   24 ++++++++++++++++++++++++
 net/core/skbuff.c         |    8 ++++++++
 net/ipv4/devinet.c        |   21 ++++++++++++++++-----
 net/ipv4/ip_forward.c     |    3 +++
 net/ipv6/addrconf.c       |    6 ++++++
 net/ipv6/ip6_output.c     |    3 +++
 10 files changed, 77 insertions(+), 6 deletions(-)

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.

Re: [PATCH 0/2] Disable forwarding of LRO skbs [2nd try]

[Stephen Hemminger]

On Thu, 19 Jun 2008 19:44:56 +0100
Ben Hutchings <bhutchings@solarflare.com> wrote:

> [Re-sent with the correct Message-ID, previously eaten by mutt.]
> 
> Large Receive Offload (LRO) destroys packet headers that should be
> preserved when forwarding.  Currently it also triggers a BUG() or WARN()
> in skb_gso_segment().  We should disable it wherever forwarding is
> enabled, and discard LRO skbs with a warning if it is turned back on.
> 
> Since the previous version of these patches, I have:
> - Tightened the test for LRO'd skbs, so it should not catch skbs from
>   VM guests that want GSO
> - Made the test an inline function, with the warning a separate extern
>   function
> - Rebased against net-next-2.6
> 

I like that it covers both cases and looks clean. If anyone ever gets
around to rewriting the network device driver chapter in the linux
kernel book(s) this should be covered in more detail.