ethernet: T9228: only warn about unsupported NIC features when node changed

EthernetIf.update() re-applies every ethernet knob on every commit touching
the interface. The capability messages (offload, flow-control, ring-buffer,
coalesce, switchdev) are emitted whenever the CLI-desired state differs from
what the driver reports - and on drivers where a feature is fixed
(virtio_net, vmxnet3, vif, veth, ...) that is permanently true. The message
is correct the first time, but it then re-appears on unrelated commits like
an interface description or IP address change.

Record in interfaces_ethernet.py which of the affected CLI nodes were
altered - the mechanism already used for speed_duplex_changed - and pass it
to the setters via a "warn" argument. Settings are still applied
unconditionally, only the message is gated.

While at it, consolidate the seven offload setters onto a common helper and
use Warning() instead of print().

1 files changed, 27 insertions, 0 deletions

diff --git a/src/conf_mode/interfaces_ethernet.py b/src/conf_mode/interfaces_ethernet.py
index 16ff90300..45bd47e86 100755
--- a/src/conf_mode/interfaces_ethernet.py
+++ b/src/conf_mode/interfaces_ethernet.py
@@ -25,7 +25,9 @@ from vyos.configdep import call_dependents
 from vyos.configdict import get_interface_dict
 from vyos.configdict import is_node_changed
 from vyos.configdict import is_vrf_changed
+from vyos.configdict import node_changed
 from vyos.configdict import get_flowtable_interfaces
+from vyos.configdiff import Diff
 from vyos.configverify import verify_address
 from vyos.configverify import verify_dhcpv6
 from vyos.configverify import verify_interface_exists
@@ -178,6 +180,31 @@ def get_config(config=None):
     tmp = is_node_changed(conf, base + [ifname, 'evpn'])
     if tmp: ethernet.update({'frr_dict' : get_frrender_dict(conf)})
 
+    # T9228: Some NIC drivers do not support changing all settings we offer on
+    # the CLI. The warning telling the user about the missing driver support is
+    # emitted while applying the configuration - which happens on every commit
+    # touching this interface. Record which nodes have been changed so the
+    # warning is only displayed if the node in question was altered, and not on
+    # any unrelated change like an interface description or IP address.
+    tmp = node_changed(
+        conf,
+        base + [ifname, 'offload'],
+        key_mangling=('-', '_'),
+        expand_nodes=Diff.ADD | Diff.DELETE,
+    )
+    if tmp:
+        ethernet.update({'offload_changed': tmp})
+
+    for node, key in {
+        'disable-flow-control': 'flow_control_changed',
+        'ring-buffer': 'ring_buffer_changed',
+        'interrupt-coalescing': 'coalesce_changed',
+        'switchdev': 'switchdev_changed',
+    }.items():
+        tmp = is_node_changed(conf, base + [ifname, node])
+        if tmp:
+            ethernet.update({key: {}})
+
     ethernet['flowtable_interfaces'] = get_flowtable_interfaces(conf)
 
     vpp_config = conf.get_config_dict(