I have done a similar fix few months ago. The commit tries to avoid an
inconsistent result caused by using different xcfg pointers.
https://github.com/openvswitch/ovs/pull/210/commits/ec75e8d9bb0e16690447b40b39d2fd0fb0f7aae2
I think a few more place fixes needed for this patch:
update_mcast_snooping_table()
xlate_normal_mcast_send_group()
xlate_normal_mcast_send_mrouters()
xlate_normal_mcast_send_fports()
> Thank you for the analysis and the fix! I applied this to master and
> backported as far as branch-2.8.
>
> On Fri, Jan 19, 2018 at 08:12:30AM +0000, Lilijun (Jerry) wrote:
>> Hi all,
>>
>> In my test, the new datapath flow which has the same in_port and actions
>> output port was found using ovs-appctl dpctl/dump-flows.
>> Then the mac address will move from one port to another and back it again in
>> the physical switch. This problem result in the VM's traffic become abnormal.
>>
>> My test key steps:
>> 1) There are three VM using ovs bridge and intel 82599 nics as uplink
>> port, deployed in different hosts connecting to the same physical switch.
>> They can be named using VM-A, VM-B and VM-C, Host-A, Host-B, Host-C.
>> 2) VM-A send many unicast packets to VM-B, and VM-B also send unicast
>> packets to VM-A.
>> 3) VM-C ping VM-A continuously, and do ovs port add/delete testing in
>> Host-C ovs bridge.
>> 4) In some abormal scence, the physical switch clear all the mac-entry
>> on each ports. Then Host-C ovs bridge's uplink port will receive two
>> direction packets(VM-A to VM-B, and VM-B to VM-A).
>>
>> The expected result is that this two direction packets should be droppd in
>> the uplink port. Because the dst port of this packets is the uplink port
>> which is also the src port by looking ovs bridge's mac-entry table learned
>> by ovs NORMAL rules.
>> But the truth is some packets being sent back to uplink port and physical
>> switch. And then VM-A's mac was moved to the physical switch port of Host-C
>> from the port of Host-A, as a reulst, VM-C ping VM-A failed at this time.
>> When this problem occurs, the abnormal ovs datapath's flow "in_port(2)
>> actions:2" was found by executing the command "ovs-appctl dpctl/dump-flows".
>>
>> Currently, xlate_normal() uses xbundle pointer compare to verify the
>> packet's dst port whether is same with its input port. This implemention may
>> be wrong while calling xlate_txn_start/xlate_txn_commit in type_run() at the
>> same time,
>> because xcfg/xbridge/xbundle object was reallocated and copied just before
>> we lookup the dst mac_port and mac_xbundle. Then mac_xbundle and in_xbundle
>> are same related with the uplink port but not same object pointer.
>>
>> And we can fix this bug by adding ofbundle check conditions shown in my
>> patch.
>>
>> Signed-off-by: Lilijun <jerry.lilijun at huawei.com>
>>
>>
>> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
>> index d94e9dc..b7a8b55 100644
>> --- a/ofproto/ofproto-dpif-xlate.c
>> +++ b/ofproto/ofproto-dpif-xlate.c
>> @@ -2604,7 +2604,9 @@ xlate_normal_mcast_send_rports(struct xlate_ctx *ctx,
>> xcfg = ovsrcu_get(struct xlate_cfg *, &xcfgp);
>> LIST_FOR_EACH(rport, node, &ms->rport_list) {
>> mcast_xbundle = xbundle_lookup(xcfg, rport->port);
>> - if (mcast_xbundle && mcast_xbundle != in_xbundle) {
>> + if (mcast_xbundle
>> + && mcast_xbundle != in_xbundle
>> + && mcast_xbundle->ofbundle != in_xbundle->ofbundle) {
>> xlate_report(ctx, OFT_DETAIL,
>> "forwarding report to mcast flagged port");
>> output_normal(ctx, mcast_xbundle, xvlan);
>> @@ -2626,6 +2628,7 @@ xlate_normal_flood(struct xlate_ctx *ctx, struct
>> xbundle *in_xbundle,
>> LIST_FOR_EACH (xbundle, list_node, &ctx->xbridge->xbundles) {
>> if (xbundle != in_xbundle
>> + && xbundle->ofbundle != in_xbundle->ofbundle
>> && xbundle_includes_vlan(xbundle, xvlan)
>> && xbundle->floodable
>> && !xbundle_mirror_out(ctx->xbridge, xbundle)) {
>> @@ -2833,7 +2836,9 @@ xlate_normal(struct xlate_ctx *ctx)
>> if (mac_port) {
>> struct xlate_cfg *xcfg = ovsrcu_get(struct xlate_cfg *, &xcfgp);
>> struct xbundle *mac_xbundle = xbundle_lookup(xcfg, mac_port);
>> - if (mac_xbundle && mac_xbundle != in_xbundle) {
>> + if (mac_xbundle
>> + && mac_xbundle != in_xbundle
>> + && mac_xbundle->ofbundle != in_xbundle->ofbundle) {
>> xlate_report(ctx, OFT_DETAIL, "forwarding to learned port");
>> output_normal(ctx, mac_xbundle, &xvlan);
>> } else if (!mac_xbundle) {
>>
>>
>> _______________________________________________
>> dev mailing list
>> dev at openvswitch.org
>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
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