[PATCH v2 2/2] lib: Fix calling of virNetworkUpdate() driver callback
Michal Privoznik
mprivozn at redhat.com
Tue Mar 16 11:44:06 UTC 2021
The order in which virNetworkUpdate() accepts @section and
@command arguments is not the same as in which it passes them
onto networkUpdate() callback. Until recently, it did not really
matter, because calling the API on client side meant arguments
were encoded in reversed order (compared to the public API), but
then on the server it was fixed again - because the server
decoded RPC (still swapped), called public API (still swapped)
and in turn called the network driver callback (with reversing
the order - so magically fixing the order).
Long story short, if the public API is called even number of
times those swaps cancel each other out. The problem is when the
API is called an odd numbed of times - which happens with split
daemons and the right URI. There's one call in the client (e.g.
virsh net-update), the other in a hypervisor daemon (say
virtqemud) which ends up calling the API in the virnetworkd.
The fix is obvious - fix the order in which arguments are passed
to the callback.
But, to maintain compatibility with older, yet unfixed, daemons
new connection feature is introduced. The feature is detected
just before calling the callback and allows client to pass
arguments in correct order (talking to fixed daemon) or in
reversed order (talking to older daemon).
Unfortunately, older client talking to newer daemon can't be
fixed. Let's hope that it's less frequent scenario.
Fixes: 574b9bc66b6b10cc4cf50f299c3f0ff55f2cbefb
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1870552
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/esx/esx_driver.c | 3 +++
src/libvirt-network.c | 24 ++++++++++++++++++++++--
src/libvirt_internal.h | 5 +++++
src/libxl/libxl_driver.c | 1 +
src/lxc/lxc_driver.c | 1 +
src/network/bridge_driver.c | 2 ++
src/openvz/openvz_driver.c | 1 +
src/qemu/qemu_driver.c | 1 +
src/remote/remote_daemon_dispatch.c | 1 +
src/test/test_driver.c | 1 +
10 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c
index 96cc8bda0d..5c96ab4de0 100644
--- a/src/esx/esx_driver.c
+++ b/src/esx/esx_driver.c
@@ -1037,6 +1037,9 @@ esxConnectSupportsFeature(virConnectPtr conn, int feature)
return priv->vCenter &&
supportsVMotion == esxVI_Boolean_True ? 1 : 0;
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
+ return 1;
+
case VIR_DRV_FEATURE_FD_PASSING:
case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
case VIR_DRV_FEATURE_MIGRATION_DIRECT:
diff --git a/src/libvirt-network.c b/src/libvirt-network.c
index b84389f762..145487d599 100644
--- a/src/libvirt-network.c
+++ b/src/libvirt-network.c
@@ -543,8 +543,28 @@ virNetworkUpdate(virNetworkPtr network,
if (conn->networkDriver && conn->networkDriver->networkUpdate) {
int ret;
- ret = conn->networkDriver->networkUpdate(network, section, command,
- parentIndex, xml, flags);
+ int rc;
+
+ /* Since its introduction in v0.10.2-rc1~9 the @section and @command
+ * arguments were mistakenly swapped when passed to driver's callback.
+ * Detect if the other side is fixed already or not. */
+ rc = VIR_DRV_SUPPORTS_FEATURE(conn->driver, conn,
+ VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER);
+
+ VIR_DEBUG("Argument order feature detection returned: %d", rc);
+ if (rc < 0)
+ goto error;
+
+ if (rc == 0) {
+ /* Feature not supported, preserve swapped order */
+ ret = conn->networkDriver->networkUpdate(network, section, command,
+ parentIndex, xml, flags);
+ } else {
+ /* Feature supported, correct order can be used */
+ ret = conn->networkDriver->networkUpdate(network, command, section,
+ parentIndex, xml, flags);
+ }
+
if (ret < 0)
goto error;
return ret;
diff --git a/src/libvirt_internal.h b/src/libvirt_internal.h
index 2bf7744bd6..f4e592922d 100644
--- a/src/libvirt_internal.h
+++ b/src/libvirt_internal.h
@@ -126,6 +126,11 @@ typedef enum {
* Support for driver close callback rpc
*/
VIR_DRV_FEATURE_REMOTE_CLOSE_CALLBACK = 15,
+
+ /*
+ * Whether the virNetworkUpdate() API implementation passes arguments to
+ * the driver's callback in correct order. */
+ VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER = 16,
} virDrvFeature;
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index e3d769b5d9..f82095ffc7 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -5752,6 +5752,7 @@ libxlConnectSupportsFeature(virConnectPtr conn, int feature)
case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
case VIR_DRV_FEATURE_MIGRATION_PARAMS:
case VIR_DRV_FEATURE_MIGRATION_P2P:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
return 1;
case VIR_DRV_FEATURE_FD_PASSING:
case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index 8e0ec82e0b..2db544c945 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -1651,6 +1651,7 @@ lxcConnectSupportsFeature(virConnectPtr conn, int feature)
switch ((virDrvFeature) feature) {
case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
return 1;
case VIR_DRV_FEATURE_FD_PASSING:
case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 7c9e36c625..14db9ffc82 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -951,6 +951,8 @@ networkConnectSupportsFeature(virConnectPtr conn, int feature)
return -1;
switch ((virDrvFeature) feature) {
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
+ return 1;
case VIR_DRV_FEATURE_MIGRATION_V2:
case VIR_DRV_FEATURE_MIGRATION_V3:
case VIR_DRV_FEATURE_MIGRATION_P2P:
diff --git a/src/openvz/openvz_driver.c b/src/openvz/openvz_driver.c
index e898af85ab..9f65dff5d1 100644
--- a/src/openvz/openvz_driver.c
+++ b/src/openvz/openvz_driver.c
@@ -1992,6 +1992,7 @@ openvzConnectSupportsFeature(virConnectPtr conn G_GNUC_UNUSED, int feature)
switch ((virDrvFeature) feature) {
case VIR_DRV_FEATURE_MIGRATION_PARAMS:
case VIR_DRV_FEATURE_MIGRATION_V3:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
return 1;
case VIR_DRV_FEATURE_FD_PASSING:
case VIR_DRV_FEATURE_MIGRATE_CHANGE_PROTECTION:
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 16c5ccae45..0ca08b3292 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -1238,6 +1238,7 @@ qemuConnectSupportsFeature(virConnectPtr conn, int feature)
case VIR_DRV_FEATURE_XML_MIGRATABLE:
case VIR_DRV_FEATURE_MIGRATION_OFFLINE:
case VIR_DRV_FEATURE_MIGRATION_PARAMS:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
return 1;
case VIR_DRV_FEATURE_MIGRATION_DIRECT:
case VIR_DRV_FEATURE_MIGRATION_V1:
diff --git a/src/remote/remote_daemon_dispatch.c b/src/remote/remote_daemon_dispatch.c
index 9700dba450..f57ad0e0c9 100644
--- a/src/remote/remote_daemon_dispatch.c
+++ b/src/remote/remote_daemon_dispatch.c
@@ -4995,6 +4995,7 @@ static int remoteDispatchConnectSupportsFeature(virNetServerPtr server G_GNUC_UN
case VIR_DRV_FEATURE_XML_MIGRATABLE:
case VIR_DRV_FEATURE_MIGRATION_OFFLINE:
case VIR_DRV_FEATURE_MIGRATION_PARAMS:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
default:
if ((supported = virConnectSupportsFeature(conn, args->feature)) < 0)
goto cleanup;
diff --git a/src/test/test_driver.c b/src/test/test_driver.c
index 01b3e7bc82..019d61fce1 100644
--- a/src/test/test_driver.c
+++ b/src/test/test_driver.c
@@ -1590,6 +1590,7 @@ testConnectSupportsFeature(virConnectPtr conn G_GNUC_UNUSED,
{
switch ((virDrvFeature) feature) {
case VIR_DRV_FEATURE_TYPED_PARAM_STRING:
+ case VIR_DRV_FEATURE_NETWORK_UPDATE_HAS_CORRECT_ORDER:
return 1;
case VIR_DRV_FEATURE_MIGRATION_V2:
case VIR_DRV_FEATURE_MIGRATION_V3:
--
2.26.2
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