kern/57100: disable hardware checksums when using bridge(4).

[Roman Kurakin]

Hi,
    Just one more idea. We may add some sysctl option like 
bridge.froce_hw_checksum.

rik

Roman Kurakin wrote:

> Also:
>    http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/67823
> It was send by my friend, and his server runs with this patch.
> I guess that it should be idential to what you send here. If not
> you may contact him and ask to try your one.
>
>    By the way, I thought that should be better solution. For
> example, why not to tag packets if they already checksumed
> or not?
>
> rik
>
> Bruce M Simpson:
>
>> Here is a somewhat improved patch for tweaking the behaviour of the 
>> bridge
>> code with respect to disabling the hardware-assist-checksum features of
>> driver instances which are members of the bridge.
>>
>> I don't make use of the bridge code so I'd appreciate it if others 
>> who do
>> could test this patch.
>>
>> To disable *all* capabilities, setting 
>> net.link.ether.bridge.hwassmask to
>> 0 should suffice.
>>
>> Regards,
>> BMS
>>  
>>
>> ------------------------------------------------------------------------
>>
>> This patch implements a sysctl MIB variable, 
>> net.link.ether.bridge.hwassmask,
>> which may be used to specify a bitmask which is applied to each member
>> interface of a bridge to selectively disable interface hardware assist
>> capabilities, and provides finer run-time control over such behaviour.
>>
>> Index: bridge.c
>> ===================================================================
>> RCS file: /home/ncvs/src/sys/net/bridge.c,v
>> retrieving revision 1.79
>> diff -u -p -r1.79 bridge.c
>> --- bridge.c    15 Jun 2004 23:57:41 -0000    1.79
>> +++ bridge.c    3 Jul 2004 17:33:47 -0000
>> @@ -204,6 +204,10 @@ SYSCTL_NODE(_net_link_ether, OID_AUTO, b
>> static char bridge_version[] = "031224";
>> SYSCTL_STRING(_net_link_ether_bridge, OID_AUTO, version, CTLFLAG_RD,
>>     bridge_version, 0, "software version");
>> +static u_long bridge_hwassmask = 0xFFFFFFFFUL;
>> +SYSCTL_ULONG(_net_link_ether_bridge, OID_AUTO, hwassmask, CTLFLAG_RW,
>> +    &bridge_hwassmask, 0,
>> +    "Mask to apply to if_hwassist field for bridge interfaces");
>>
>> #define BRIDGE_DEBUG
>> #ifdef BRIDGE_DEBUG
>> @@ -391,6 +395,7 @@ bridge_off(void)
>>
>>     if ( b->flags & IFF_BDG_PROMISC ) {
>>         ifpromisc(ifp, 0);
>> +        ifp->if_hwassist = b->hwassist;
>>         b->flags &= ~(IFF_BDG_PROMISC|IFF_MUTE) ;
>>         DPRINTF(("%s: %s promisc OFF if_flags 0x%x "
>>         "bdg_flags 0x%x\n", __func__, ifp->if_xname,
>> @@ -433,6 +438,8 @@ bridge_on(void)
>>         if_up(ifp);
>>     }
>>     if ( !(b->flags & IFF_BDG_PROMISC) ) {
>> +        b->hwassist = ifp->if_hwassist;
>> +        ifp->if_hwassist &= bridge_hwassmask;
>>         (void) ifpromisc(ifp, 1);
>>         b->flags |= IFF_BDG_PROMISC ;
>>         DPRINTF(("%s: %s promisc ON if_flags 0x%x bdg_flags 0x%x\n",
>> Index: bridge.h
>> ===================================================================
>> RCS file: /home/ncvs/src/sys/net/bridge.h,v
>> retrieving revision 1.12
>> diff -u -p -r1.12 bridge.h
>> --- bridge.h    15 Nov 2002 00:00:14 -0000    1.12
>> +++ bridge.h    3 Jul 2004 17:26:44 -0000
>> @@ -48,6 +48,7 @@ struct bdg_softc {
>> #define IFF_MUTE        0x0002  /* mute this if for bridging.   */
>> #define IFF_USED        0x0004  /* use this if for bridging.    */
>>     struct cluster_softc *cluster;
>> +    u_long hwassist;        /* saved ifp->if_hwassist field */
>> } ;
>>
>> extern struct bdg_softc *ifp2sc;
>>  
>>
>> ------------------------------------------------------------------------
>>
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>>
>
>
>
>
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