On Fri, May 29, 2020 at 3:41 PM Miroslav Kubiczek < [email protected]> wrote:
> > On 29. 05. 20 11:29, Numan Siddique wrote: > > On Fri, May 29, 2020 at 2:25 PM Miroslav Kubiczek < > [email protected]> wrote: > >> Hi, >> >> I have finally implemented flows with check_pkt_larger action. Partial flow >> dump is here: >> >> table=0, priority=100 >> actions=check_pkt_larger(60)->NXM_NX_REG0[0],resubmit(,1) >> table=1, priority=1000,reg0=0x1 actions=resubmit(,2) >> table=1, priority=100,reg0=0 actions=resubmit(,3) >> >> I run a test which sends UDP packets (with VLAN) with size: 58, 59, 62, 63 >> and 69 in a loop. Only the packet with 69 match the action (1st line in >> table=1). >> >> In 2nd test I set check_pkt_larger just by one byte less to 59 and then all >> the above packets match. So the precision seems to be rounded to 8 bytes or >> something like that. >> Can this be fixed to be more precise ideally to exact 1 byte? >> >> > Can you try without VLAN and see the accuracy ? > > I tried without VLAN, it's not accurate. > This is how the pkt length comparison is done in vswitchd - https://github.com/openvswitch/ovs/blob/master/ofproto/ofproto-dpif-xlate.c#L6265 in kernel datapath - https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux/+/refs/heads/master/net/openvswitch/actions.c#1183 Thanks Numan > > > man ovs-actions for check_pkt_larger says > > **** > Syntax: > check_pkt_larger(pkt_len)->dst > > Checks if the packet is larger than the specified length in > pkt_len. If so, stores 1 in dst, which should be a 1-bit field; if not, > stores 0. > > The packet length to check againt the argument pkt_len includes the > L2 header and L2 payload of the packet, but not the VLAN tag (if present). > > Examples: > · check_pkt_larger(1500)->reg0[0] > · check_pkt_larger(8000)->reg9[10] > > ****** > > Thanks > Numan > > Thanks, >> Miro >> >> >> >> >> _______________________________________________ > discuss mailing list > [email protected] > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss >
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