Please discard my previous email, I misunderstood your question.
The packet above is
dnl outer IP: Source: 172.16.180.105 Destination: 172.16.180.106
dnl inner IP: Source: 192.168.10.104 Destination: 192.168.10.105
So the bfd_should_process_flow returns false.
Yes, you are correct and this patch returns false in this case.
For the above packet, outer IP is extracted as tunnel info, flow->nw_dst is
192.168.10.105.
So bfd_should_process_flow returns false.
Thanks,
Yifeng
On Wed, Jul 22, 2020 at 11:02 AM Yifeng Sun <pkusunyif...@gmail.com> wrote:
> Thanks for reviewing.
>
> For these two packets:
>
> dnl outer IP: Source: 172.16.180.105 Destination: 172.16.180.106
> This one is normal BFD packet, bfd_should_process_flow should return
> true, as used to.
>
> dnl inner IP: Source: 192.168.10.104 Destination: 192.168.10.105
> This one is overlay BFD packet, bfd_should_process_flow should return
> false so this packet won't be intercepted by OVS's BFD engine.
>
> Thanks,
> Yifeng
>
> On Wed, Jul 22, 2020 at 10:54 AM William Tu <u9012...@gmail.com> wrote:
>
>> On Wed, Jul 22, 2020 at 01:59:04AM -0700, Yifeng Sun wrote:
>> > Current OVS intercepts and processes all BFD packets, thus VM-2-VM
>> > BFD packets get lost and the recipient VM never sees them.
>> >
>> > This patch fixes it by only intercepting and processing BFD packets
>> > destined to a configured BFD instance, and other BFD packets are made
>> > available to the OVS flow table for forwarding.
>> >
>> > This patch adds new test to validate BFD overlay.
>> >
>> > This patch keeps BFD's backward compatibility.
>> >
>> > Signed-off-by: Yifeng Sun <pkusunyif...@gmail.com>
>> > ---
>> > v1->v2: Add test by William's suggestion.
>> >
>> > lib/bfd.c | 16 +++++++++++++---
>> > tests/system-traffic.at | 42
>> ++++++++++++++++++++++++++++++++++++++++++
>> > vswitchd/vswitch.xml | 7 +++++++
>> > 3 files changed, 62 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/lib/bfd.c b/lib/bfd.c
>> > index cc8c6857afa4..3c965699ace3 100644
>> > --- a/lib/bfd.c
>> > +++ b/lib/bfd.c
>> > @@ -149,6 +149,9 @@ BUILD_ASSERT_DECL(BFD_PACKET_LEN == sizeof(struct
>> msg));
>> > #define FLAGS_MASK 0x3f
>> > #define DEFAULT_MULT 3
>> >
>> > +#define BFD_DEFAULT_SRC_IP 0xA9FE0101 /* 169.254.1.1 */
>> > +#define BFD_DEFAULT_DST_IP 0xA9FE0100 /* 169.254.1.0 */
>> > +
>> > struct bfd {
>> > struct hmap_node node; /* In 'all_bfds'. */
>> > uint32_t disc; /* bfd.LocalDiscr. Key in 'all_bfds'
>> hmap. */
>> > @@ -457,9 +460,9 @@ bfd_configure(struct bfd *bfd, const char *name,
>> const struct smap *cfg,
>> > &bfd->rmt_eth_dst);
>> >
>> > bfd_lookup_ip(smap_get_def(cfg, "bfd_src_ip", ""),
>> > - htonl(0xA9FE0101) /* 169.254.1.1 */, &bfd->ip_src);
>> > + htonl(BFD_DEFAULT_SRC_IP), &bfd->ip_src);
>> > bfd_lookup_ip(smap_get_def(cfg, "bfd_dst_ip", ""),
>> > - htonl(0xA9FE0100) /* 169.254.1.0 */, &bfd->ip_dst);
>> > + htonl(BFD_DEFAULT_DST_IP), &bfd->ip_dst);
>> >
>> > forwarding_if_rx = smap_get_bool(cfg, "forwarding_if_rx", false);
>> > if (bfd->forwarding_if_rx != forwarding_if_rx) {
>> > @@ -674,7 +677,14 @@ bfd_should_process_flow(const struct bfd *bfd_,
>> const struct flow *flow,
>> > memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto);
>> > if (flow->nw_proto == IPPROTO_UDP
>> > && !(flow->nw_frag & FLOW_NW_FRAG_LATER)
>> > - && tp_dst_equals(flow, BFD_DEST_PORT, wc)) {
>> > + && tp_dst_equals(flow, BFD_DEST_PORT, wc)
>> > + && (bfd->ip_src == htonl(BFD_DEFAULT_SRC_IP)
>> > + || bfd->ip_src == flow->nw_dst)) {
>> > +
>> > + if (bfd->ip_src == flow->nw_dst) {
>> > + memset(&wc->masks.nw_dst, 0xffffffff, sizeof
>> wc->masks.nw_dst);
>> > + }
>> > +
>> > bool check_tnl_key;
>> >
>> > atomic_read_relaxed(&bfd->check_tnl_key, &check_tnl_key);
>> > diff --git a/tests/system-traffic.at b/tests/system-traffic.at
>> > index 2a0fbadff4a1..80b58996d530 100644
>> > --- a/tests/system-traffic.at
>> > +++ b/tests/system-traffic.at
>> > @@ -6289,3 +6289,45 @@ OVS_WAIT_UNTIL([cat p2.pcap | egrep "0x0050:
>> *0000 *0000 *5002 *2000 *b85e *0000
>> >
>> > OVS_TRAFFIC_VSWITCHD_STOP
>> > AT_CLEANUP
>> > +
>> > +AT_SETUP([bfd - BFD overlay])
>> > +OVS_CHECK_GENEVE()
>> > +
>> > +OVS_TRAFFIC_VSWITCHD_START()
>> > +
>> > +AT_CHECK([ovs-vsctl -- set bridge br0
>> other-config:hwaddr=\"f2:ff:00:00:00:01\"])
>> > +ADD_BR([br-underlay], [set bridge br-underlay
>> other-config:hwaddr=\"ee:09:e0:4d:bf:31\"])
>> > +
>> > +AT_CHECK([ovs-ofctl add-flow br0 "actions=normal"])
>> > +AT_CHECK([ovs-ofctl add-flow br-underlay "actions=normal"])
>> > +
>> > +ADD_NAMESPACES(at_ns0)
>> > +
>> > +dnl Set up underlay link from host into the namespace using veth pair.
>> > +ADD_VETH(p0, at_ns0, br-underlay, "172.16.180.105/24",
>> 4e:12:5d:6c:74:3d)
>> > +AT_CHECK([ip addr add dev br-underlay "172.16.180.106/24"])
>> > +AT_CHECK([ip link set dev br-underlay up])
>> > +
>> > +dnl Set up tunnel endpoints on OVS outside the namespace.
>> > +ADD_OVS_TUNNEL([geneve], [br0], [at_gnv0], [172.16.180.105], [
>> 192.168.10.100/24],
>> > + [options:packet_type=ptap])
>> > +
>> > +dnl Certain Linux distributions, like CentOS, have default iptable
>> rules
>> > +dnl to reject input traffic from br-underlay. Here we add a rule to
>> walk
>> > +dnl around it.
>> > +iptables -I INPUT 1 -i br-underlay -j ACCEPT
>> > +on_exit 'iptables -D INPUT 1'
>> > +
>> > +dnl Firstly, test normal BFD packet.
>> > +ovs-ofctl -O OpenFlow13 packet-out br-underlay "in_port=1
>> packet=ee09e04dbf314e125d6c743d080045c0006624d94000401153f9ac10b469ac10b46a739f17c1005247f900806558000000000023200000016a0f5a9ed376080045c0003400000000ff11fa03ac10b469ac10b46ac0070ec80020000021c003187b3c96ebbc96b962000186a0000f424000000000
>> actions=NORMAL"
>> The packet above is
>> dnl outer IP: Source: 172.16.180.105 Destination: 172.16.180.106
>> dnl inner IP: Source: 172.16.180.105 Destination: 172.16.180.106
>>
>> And why does this trigger ovs to process it ex: bfd_should_process_flow()
>> return true?
>> In your patch, you're adding extra check
>> bfd->ip_src == flow->nw_dst
>> and here
>> bfd->ip_src is default 169.254.1.1
>> flow->nw_dst is 172.16.180.106
>>
>>
>> > +dnl Next we test overlay BFD packet.
>> > +ovs-ofctl -O OpenFlow13 packet-out br-underlay "in_port=1
>> packet=ee09e04dbf314e125d6c743d08004500005b2558400040115445ac10b469ac10b46a6b1017c1004722c1024065580000000001048001001803005254009d0b6d5254000c89840800450000210e22400040119688c0a80a68c0a80a6995cd0ec8000dd342746573740a
>> actions=NORMAL"
>>
>> The packet above is
>> dnl outer IP: Source: 172.16.180.105 Destination: 172.16.180.106
>> dnl inner IP: Source: 192.168.10.104 Destination: 192.168.10.105
>> So the bfd_should_process_flow returns false.
>>
>> > +
>> > +ovs-dpctl dump-flows > datapath-flows.txt
>> > +dnl BFD packet was handled by BFD flow.
>> > +AT_FAIL_IF([cat datapath-flows.txt | egrep
>> "tunnel\(.*,src=172.16.180.105,dst=172.16.180.106,.*,eth\(\),eth_type\(0x0800\),ipv4\(proto=17,.*\),udp\(dst=3784\),
>> .*, actions:userspace\(pid=.*,slow_path\(bfd\)\)" 2>&1 1>/dev/null])
>> > +dnl Overlay BFD packet was handled by non-BFD flows.
>> > +AT_FAIL_IF([cat datapath-flows.txt | egrep
>> "tunnel\(.*,src=172.16.180.105,dst=172.16.180.106,.*,eth\(.*\),eth_type\(0x0800\),ipv4\(src=192.168.10.104,dst=192.168.10.105,proto=17,.*\),udp\(.*,dst=3784\),
>> .*, actions:drop" 2>&1 1>/dev/null])
>> > +
>> > +OVS_TRAFFIC_VSWITCHD_STOP
>> > +AT_CLEANUP
>>
>>
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