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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