OVS allows overlapping megaflows, as long as the actions of these
megaflows are equal. However, the current implementation of action
modification relies on flow_lookup instead of ufid, this could result
in looking up a wrong megaflow and make the ukeys and megaflows inconsistent
Just like the test case in the patch, at first we have a rule with the
prefix:
10.1.2.0/24
and we will get a megaflow with prefixes 10.1.2.2/24 when a packet with IP
10.1.2.2 is received.
Then suppose we change the rule into 10.1.0.0/16. OVS prefers to keep the
10.1.2.2/24 megaflow and just changes its action instead of extending
the prefix into 10.1.2.2/16.
then suppose we have a 10.1.0.2 packet, since it misses the megaflow,
this time, we will have an overlapping megaflow with the right prefix:
10.1.0.2/16
now we have two megaflows:
10.1.2.2/24
10.1.0.2/16
last, suppose we have changed the ruleset again. The revalidator this
time still decides to change the actions of both megaflows instead of
deleting them.
The dpif_netdev_flow_put will search the megaflow to modify with unmasked
keys, however it might lookup the wrong megaflow as the key 10.1.2.2 matches
both 10.1.2.2/24 and 10.1.0.2/16!
This patch changes the megaflow lookup code in modification path into
relying the ufid to find the correct megaflow instead of key lookup.
Signed-off-by: Peng He <hepeng.0...@bytedance.com>
---
lib/dpif-netdev.c | 45 ++++++++++++++++++++++++++++++---------------
tests/pmd.at | 47 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+), 15 deletions(-)
diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
index 70b953ae6..8479630b8 100644
--- a/lib/dpif-netdev.c
+++ b/lib/dpif-netdev.c
@@ -4191,7 +4191,7 @@ flow_put_on_pmd(struct dp_netdev_pmd_thread *pmd,
const struct dpif_flow_put *put,
struct dpif_flow_stats *stats)
{
- struct dp_netdev_flow *netdev_flow;
+ struct dp_netdev_flow *netdev_flow = NULL;
int error = 0;
if (stats) {
@@ -4199,16 +4199,35 @@ flow_put_on_pmd(struct dp_netdev_pmd_thread *pmd,
}
ovs_mutex_lock(&pmd->flow_mutex);
- netdev_flow = dp_netdev_pmd_lookup_flow(pmd, key, NULL);
- if (!netdev_flow) {
- if (put->flags & DPIF_FP_CREATE) {
- dp_netdev_flow_add(pmd, match, ufid, put->actions,
- put->actions_len, ODPP_NONE);
+ if (put->ufid) {
+ netdev_flow = dp_netdev_pmd_find_flow(pmd, put->ufid,
+ put->key, put->key_len);
+ } else {
+ /* Use key instead of the locally generated ufid
+ * to search netdev_flow. */
+ netdev_flow = dp_netdev_pmd_lookup_flow(pmd, key, NULL);
+ }
+
+ if (put->flags & DPIF_FP_CREATE) {
+ if (!netdev_flow) {
+ dp_netdev_flow_add(pmd, match, ufid,
+ put->actions, put->actions_len, ODPP_NONE);
} else {
- error = ENOENT;
+ error = EEXIST;
}
- } else {
- if (put->flags & DPIF_FP_MODIFY) {
+ goto exit;
+ }
+
+ if (put->flags & DPIF_FP_MODIFY) {
+ if (!netdev_flow) {
+ error = ENOENT;
+ } else {
+ if (!put->ufid && !flow_equal(&match->flow, &netdev_flow->flow)) {
+ /* Overlapping flow. */
+ error = EINVAL;
+ goto exit;
+ }
+
struct dp_netdev_actions *new_actions;
struct dp_netdev_actions *old_actions;
@@ -4239,15 +4258,11 @@ flow_put_on_pmd(struct dp_netdev_pmd_thread *pmd,
* counter, and subtracting it before outputting the stats */
error = EOPNOTSUPP;
}
-
ovsrcu_postpone(dp_netdev_actions_free, old_actions);
- } else if (put->flags & DPIF_FP_CREATE) {
- error = EEXIST;
- } else {
- /* Overlapping flow. */
- error = EINVAL;
}
}
+
+exit:
ovs_mutex_unlock(&pmd->flow_mutex);
return error;
}
diff --git a/tests/pmd.at b/tests/pmd.at
index 48f3d432d..b03cd831e 100644
--- a/tests/pmd.at
+++ b/tests/pmd.at
@@ -1300,3 +1300,50 @@ OVS_WAIT_UNTIL([tail -n +$LINENUM ovs-vswitchd.log |
grep "PMD load based sleeps
OVS_VSWITCHD_STOP
AT_CLEANUP
+
+AT_SETUP([PMD - revalidator wrongly modify userspace megaflows])
+
+OVS_VSWITCHD_START(
+[add-port br0 p1 \
+ -- set bridge br0 datapath-type=dummy \
+ -- set interface p1 type=dummy-pmd \
+ -- add-port br0 p2 \
+ -- set interface p2 type=dummy-pmd
+])
+
+dnl Add one openflow rule and generate a megaflow.
+AT_CHECK([ovs-ofctl add-flow br0
'table=0,in_port=p1,ip,nw_dst=10.1.2.0/24,actions=p2'])
+AT_CHECK([ovs-appctl netdev-dummy/receive p1
'ipv4(src=10.0.0.1,dst=10.1.2.2),tcp(src=1,dst=2)'])
+
+OVS_WAIT_UNTIL_EQUAL([ovs-appctl dpctl/dump-flows | sed 's/.*core:
[[0-9]]*//'], [
+recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=10.1.2.2/255.255.255.0,frag=no),
packets:0, bytes:0, used:never, actions:2])
+
+AT_CHECK([ovs-appctl netdev-dummy/receive p1
'ipv4(src=10.0.0.1,dst=10.1.2.2),tcp(src=1,dst=2)'])
+dnl Replace openflow rules, trigger the revalidation.
+AT_CHECK([echo 'table=0,in_port=p1,ip,nw_dst=10.1.0.0/16 actions=ct(commit)' |
dnl
+ ovs-ofctl --bundle replace-flows br0 -])
+AT_CHECK([ovs-appctl revalidator/wait])
+
+AT_CHECK([ovs-appctl netdev-dummy/receive p1
'ipv4(src=10.0.0.1,dst=10.1.0.2),tcp(src=1,dst=2)'])
+OVS_WAIT_UNTIL_EQUAL([ovs-appctl dpctl/dump-flows | sed 's/.*core: [[0-9]]*//'
| strip_xout_keep_actions], [
+recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=10.1.0.2/255.255.0.0,frag=no),
packets:0, bytes:0, used:never, actions:ct(commit)
+recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=10.1.2.2/255.255.255.0,frag=no),
packets:0, bytes:0, used:0.0s, actions:ct(commit)])
+
+dnl Hold the prefix 10.1.2.2/24 by another 10s.
+AT_CHECK([ovs-appctl netdev-dummy/receive p1
'ipv4(src=10.0.0.1,dst=10.1.2.2),tcp(src=1,dst=2)'])
+dnl Send more 10.1.0.2 to make 10.1.0.0/16 tuple preprend 10.1.2.0/24 tuple in
the pvector of subtables.
+for i in $(seq 0 256); do
+ AT_CHECK([ovs-appctl netdev-dummy/receive p1
'ipv4(src=10.0.0.1,dst=10.1.0.2),tcp(src=1,dst=2)'])
+done
+
+AT_CHECK([echo 'table=0,in_port=p1,ip,nw_dst=10.1.0.0/16 actions=p2' | dnl
+ ovs-ofctl --bundle replace-flows br0 -])
+
+AT_CHECK([ovs-appctl revalidator/wait])
+AT_CHECK([ovs-appctl dpctl/dump-flows | sed 's/.*core: [[0-9]]*//' |
strip_xout_keep_actions], [0], [
+recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=10.1.0.2/255.255.0.0,frag=no),
packets:0, bytes:0, used:0.0s, actions:2
+recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=10.1.2.2/255.255.255.0,frag=no),
packets:0, bytes:0, used:0.0s, actions:2
+])
+
+OVS_VSWITCHD_STOP
+AT_CLEANUP
--
2.25.1
_______________________________________________
dev mailing list
d...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
