SUN Neptune byte order bug in TCAM filter/ethtool

SUN Neptune byte order bug in TCAM filter/ethtool

[Robert Olsson]

David Miller writes:

 > >  FYI byte order seems reversed on Intel meaning you have to reverse
 > >  byte order for address and ports when adding TCAM entries via
 > >  ethtool.
 > 
 > Please report this formally with a reproduction script/commands/etc.
 > with netdev CC:'d as this is a very serious bug and exactly what I
 > tried to avoid have happen when I was so anal about the endian
 > oriented typing of the ethtool structures. :-//////////


First a disclaimer this our production system 2.6.29-rc2 but I haven't 
seen any patches since.


# This rule makes the TCAM drop pkts with IP-src 10.10.10.1 
# Note the reversed byte-order. Machine is Opteron little Endian.

ethtool -N  eth0  rx-class-rule-add ip4 udp sip 1.10.10.10 drop  

# The rule listed

ethtool  -n eth0  rx-class-rule-all 
Total 1 rules

      IPv4 Rule:   ID[84] Target[Discard]
      IP src addr[1.10.10.10] mask[255.255.255.255]
      IP dst addr[0.0.0.0] mask[0.0.0.0]
      L4 proto[UDP]
      L4 src port[0] mask[0x0]
      L4 dst port[0] mask[0x0]
      IP TOS[0x0] mask[0x0]

# The rule deleted

ethtool  -N eth0  rx-class-rule-del 84 


Cheers
					--ro

Re: SUN Neptune byte order bug in TCAM filter/ethtool

[David Miller]

From: Robert Olsson <robert@robur.slu.se>
Date: Wed, 6 May 2009 18:16:07 +0200

> # This rule makes the TCAM drop pkts with IP-src 10.10.10.1 
> # Note the reversed byte-order. Machine is Opteron little Endian.
> 
> ethtool -N  eth0  rx-class-rule-add ip4 udp sip 1.10.10.10 drop  
> 
> # The rule listed
> 
> ethtool  -n eth0  rx-class-rule-all 
> Total 1 rules
> 
>       IPv4 Rule:   ID[84] Target[Discard]
>       IP src addr[1.10.10.10] mask[255.255.255.255]
>       IP dst addr[0.0.0.0] mask[0.0.0.0]
>       L4 proto[UDP]
>       L4 src port[0] mask[0x0]
>       L4 dst port[0] mask[0x0]
>       IP TOS[0x0] mask[0x0]

I suspect that ethtool is probably to blame, the kernel seems
sane and treats the IP addresses, ports, etc. as big-endian.