[ovs-dev] [PATCHv2 2/6] ofproto-dpif: Validate ct_* field masks.

[Joe Stringer]

On 11 November 2015 at 14:20, Jarno Rajahalme <jarno at ovn.org> wrote:
> With one comment to consider below:
>
> Acked-by: Jarno Rajahalme <jarno at ovn.org>
>
>> On Nov 11, 2015, at 11:39 AM, Joe Stringer <joestringer at nicira.com> wrote:
>>
>> When inserting rules that match on connection tracking fields, datapath
>> support must be checked before allowing or denying the rule insertion.
>> Previously we only disallowed flows that had non-zero values for the
>> ct_* field, but allowed non-zero masks. This meant that, eg:
>>
>> ct_state=-trk,...
>>
>> Would be allowed, while
>>
>> ct_state=+trk,...
>>
>> Would be disallowed, due to lack of datapath support.
>>
>> Fix this by performing the check on masks instead of the flows.
>>
>> Reported-by: Ravindra Kenchappa <ravindra.kenchappa at hpe.com>
>> Signed-off-by: Joe Stringer <joestringer at nicira.com>
>> ---
>> ofproto/ofproto-dpif.c | 32 ++++++++++++++------------------
>> 1 file changed, 14 insertions(+), 18 deletions(-)
>>
>> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
>> index ab1b6a2f7d8e..ee2d267ab7b8 100644
>> --- a/ofproto/ofproto-dpif.c
>> +++ b/ofproto/ofproto-dpif.c
>> @@ -4014,30 +4014,26 @@ rule_dealloc(struct rule *rule_)
>> static enum ofperr
>> rule_check(struct rule *rule)
>> {
>> +    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->ofproto);
>> +    const struct odp_support *support;
>
>>     uint16_t ct_state, ct_zone;
>>     ovs_u128 ct_label;
>>     uint32_t ct_mark;
>>
>> -    ct_state = MINIFLOW_GET_U16(rule->cr.match.flow, ct_state);
>> -    ct_zone = MINIFLOW_GET_U16(rule->cr.match.flow, ct_zone);
>> -    ct_mark = MINIFLOW_GET_U32(rule->cr.match.flow, ct_mark);
>> -    ct_label = MINIFLOW_GET_U128(rule->cr.match.flow, ct_label);
>> +    support = &ofproto_dpif_get_support(ofproto)->odp;
>> +    ct_state = MINIFLOW_GET_U16(&rule->cr.match.mask->masks, ct_state);
>> +    ct_zone = MINIFLOW_GET_U16(&rule->cr.match.mask->masks, ct_zone);
>> +    ct_mark = MINIFLOW_GET_U32(&rule->cr.match.mask->masks, ct_mark);
>> +    ct_label = MINIFLOW_GET_U128(&rule->cr.match.mask->masks, ct_label);
>>
>> -    if (ct_state || ct_zone || ct_mark
>> -        || !ovs_u128_is_zero(&ct_label)) {
>> -        struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->ofproto);
>> -        const struct odp_support *support = &ofproto_dpif_get_support(ofproto)->odp;
>> -
>> -        if ((ct_state && !support->ct_state)
>> -            || (ct_zone && !support->ct_zone)
>> -            || (ct_mark && !support->ct_mark)
>> -            || (!ovs_u128_is_zero(&ct_label) && !support->ct_label)) {
>> -            return OFPERR_OFPBMC_BAD_FIELD;
>> -        }
>> -        if (ct_state & CS_UNSUPPORTED_MASK) {
>> -            return OFPERR_OFPBMC_BAD_MASK;
>> -        }
>> +    if ((ct_state && !support->ct_state)
>
> How about first checking the support, and then getting the miniflow data only if needed? I see that you still need to check the state for unsupported bits, but most other cases would get rid of the stack copies altogether. Also vs_u128_is_zero, if it would take it’s argument by value.

Thanks for the review. I figured the former could be in a separate
patch (3/6). The latter also could be submitted separately.