[ovs-dev] [PATCH] ovs-router: Fix selection of source IP address when a gateway ip is introduced

[Waizel, Ariel]

When adding a VXLAN tunnel that connects to a VTEP residing in a

different IP network, the tunnel source ip needs to be selected by

best fit (longest matching netmask), based on the destination VTEP

ip, and the specific route's gateway ip.

A bug in ovs-router.c made the source ip to be decided only based on

the destination ip: Thus, if all source ips available to OVS and the

destination ip are in different ip networks - no source ip is

selected, and an error is returned.

This error accorded when  using OVS-DPDK and configuring a VXLAN

tunnel, where source ip and destination ip are in different

networks, and a gateway ip was in place for the specific route.



The fix tries to match a source ip based on the gateway ip, if no

matching source ip was found based on the destination ip - This way,

the gateway becomes the first hop only if the tunnel crosses between ip networks.

Signed-off-by: Ariel Waizel <ariel.waizel at hpe.com<mailto:ariel.waizel at hpe.com>>


diff --git a/lib/ovs-router.c b/lib/ovs-router.c
index e27514a..18d0f8e 100644
--- a/lib/ovs-router.c
+++ b/lib/ovs-router.c
@@ -198,6 +198,9 @@ ovs_router_insert__(uint8_t priority, const struct in6_addr *ip6_dst,
     p->plen = plen;
     p->priority = priority;
     err = get_src_addr(ip6_dst, output_bridge, &p->src_addr);
+    if (err && ipv6_addr_is_set(gw)) {
+        err = get_src_addr(gw, output_bridge, &p->src_addr);
+    }
     if (err) {
         free(p);
         return err;
diff --git a/tests/automake.mk b/tests/automake.mk
index c170ae7..0383933 100644
--- a/tests/automake.mk
+++ b/tests/automake.mk
@@ -93,7 +93,8 @@ TESTSUITE_AT = \
        tests/ovn-nbctl.at \
       tests/ovn-sbctl.at \
        tests/ovn-controller.at \
-       tests/ovn-controller-vtep.at
+       tests/ovn-controller-vtep.at \
+       tests/ovs-route.at
 SYSTEM_KMOD_TESTSUITE_AT = \
        tests/system-common-macros.at \
diff --git a/tests/ovs-route.at b/tests/ovs-route.at
new file mode 100644
index 0000000..ac11847
--- /dev/null
+++ b/tests/ovs-route.at
@@ -0,0 +1,10 @@
+AT_BANNER([appctl route/add with gateway])
+AT_SETUP([appctl - route/add with gateway])
+AT_XFAIL_IF([test "$IS_WIN32" = "yes"])
+OVS_VSWITCHD_START([add-port br0 p2 -- set Interface p2 type=gre \
+                    options:local_ip=2.2.2.2 options:remote_ip=1.1.1.1 \
+                    -- add-port br0 p1  -- set interface p1 type=dummy])
+ovs-appctl netdev-dummy/ip4addr br0 2.2.2.2/24
+AT_CHECK([ovs-appctl ovs/route/add 1.1.1.0/24 br0 2.2.2.10], [0], [OK
+])
+AT_CLEANUP
diff --git a/tests/testsuite.at b/tests/testsuite.at
index 2123bee..a2c707d 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -75,3 +75,4 @@ m4_include([tests/ovn-nbctl.at])
m4_include([tests/ovn-sbctl.at])
m4_include([tests/ovn-controller.at])
m4_include([tests/ovn-controller-vtep.at])
+m4_include([tests/ovs-route.at])