Adding support for DSCP configuration

Allow the user to do DSCP mapping for network objects
Interface and SriovPF. The feature needs the handling
of netlink messages. The pyroute2 module is used in
the encode/decode of the netlink messages.
The persistence of the DSCP configurations are taken care
by the os-net-config-dcb-config service. The user configurations
are preserved in /var/lib/os-net-config/dcb_config.yaml

The details of the DSCP configurations could be read anytime
with the cli.
``os-net-config-dcb --show``

The new DSCP configurations can be applied with cli using
``os-net-config-dcb --config <config.yaml>``

The sample config.yaml for updating DCB only is available at
etc/os-net-config/samples/dcb_config_sample.yaml

etc/os-net-config/samples/dcb_config_sample.yaml

@@ -0,0 +1,17 @@
+# For reconfiguring the DCB, the below template could be used.
+# use ``os-net-config-dcb -c <config.yaml> `` to perform the
+# reconfiguration.
+
+dcb_config:
+  -
+    type: dcb_config
+    name: ens1f0np0
+    dscp2prio:
+        # Add the dscp configs.
+        # It requires priority and protocol
+        - priority: 5
+          protocol: 45
+        - priority: 5
+          protocol: 46
+        - priority: 6
+          protocol: 47

etc/os-net-config/samples/dcb_sample.yaml

@@ -0,0 +1,24 @@
+network_config:
+  -
+    type: sriov_pf
+    name: ens1f0np0
+    numvfs: 4
+    use_dhcp: false
+    dcb:
+      dscp2prio:
+        # Add the dscp configs.
+        # It requires priority and protocol
+        - priority: 5
+          protocol: 45
+        - priority: 5
+          protocol: 46
+        - priority: 6
+          protocol: 47
+  -
+    type: sriov_pf
+    name: ens1f1np1
+    numvfs: 4
+    use_dhcp: false
+    dcb:
+      # Remove the dscp configurations
+      dscp2prio: []

os_net_config/cli.py

@@ -22,6 +22,7 @@
 import yaml
 
 from os_net_config import common
+from os_net_config import dcb_config
 from os_net_config import impl_eni
 from os_net_config import impl_ifcfg
 from os_net_config import impl_iproute
@@ -279,6 +280,11 @@ def main(argv=sys.argv, main_logger=None):
         else:
             main_logger.warning('\n'.join(validation_errors))
 
+    # Reset the DCB Config during rerun.
+    # This is required to apply the new values and clear the old ones
+    if utils.is_dcb_config_required():
+        common.reset_dcb_map()
+
     # Look for the presence of SriovPF types in the first parse of the json
     # if SriovPFs exists then PF devices needs to be configured so that the VF
     # devices are created.
@@ -347,6 +353,13 @@ def main(argv=sys.argv, main_logger=None):
 
     files_changed = provider.apply(cleanup=opts.cleanup,
                                    activate=not opts.no_activate)
+
+    if utils.is_dcb_config_required():
+        # Apply the DCB Config
+        utils.configure_dcb_config_service()
+        dcb_apply = dcb_config.DcbApplyConfig()
+        dcb_apply.apply()
+
     if opts.noop:
         if configure_sriov:
             files_changed.update(pf_files_changed)

os_net_config/common.py

@@ -56,6 +56,18 @@
 #   promisc: "on"/"off"
 SRIOV_CONFIG_FILE = '/var/lib/os-net-config/sriov_config.yaml'
 
+# File to contain the list of DCB configurations
+# Format of the file shall be
+# - name: <pf name>
+#   dscp2prio:
+#       - protocol: 44
+#         selector: 5
+#         priority: 6
+#       - protocol: 42
+#         selector: 5
+#         priority: 3
+
+DCB_CONFIG_FILE = '/var/lib/os-net-config/dcb_config.yaml'
 
 _SYS_BUS_PCI_DEV = '/sys/bus/pci/devices'
 SYS_CLASS_NET = '/sys/class/net'
@@ -146,6 +158,74 @@ def get_file_data(filename):
         return ''
 
 
+def write_yaml_config(filepath, data):
+    os.makedirs(os.path.dirname(filepath), exist_ok=True)
+    with open(filepath, 'w') as f:
+        yaml.safe_dump(data, f, default_flow_style=False)
+
+
+def update_dcb_map(ifname, pci_addr, driver, noop, dscp2prio=None):
+    if not noop:
+        dcb_map = get_dcb_config_map()
+        for item in dcb_map:
+            if item['pci_addr'] == pci_addr:
+                item['name'] = ifname
+                item['driver'] = driver
+                item['dscp2prio'] = dscp2prio
+                break
+        else:
+            new_item = {}
+            new_item['pci_addr'] = pci_addr
+            new_item['driver'] = driver
+            new_item['name'] = ifname
+            new_item['dscp2prio'] = dscp2prio
+            dcb_map.append(new_item)
+
+        write_yaml_config(DCB_CONFIG_FILE, dcb_map)
+
+
+def write_dcb_map(dcb_map):
+    write_yaml_config(DCB_CONFIG_FILE, dcb_map)
+
+
+def get_dcb_config_map():
+    contents = get_file_data(DCB_CONFIG_FILE)
+    dcb_config_map = yaml.safe_load(contents) if contents else []
+    return dcb_config_map
+
+
+def get_empty_dcb_map():
+    contents = get_file_data(DCB_CONFIG_FILE)
+    dcb_config_map = yaml.safe_load(contents) if contents else []
+    for entry in dcb_config_map:
+        entry['dscp2prio'] = []
+    return dcb_config_map
+
+
+def add_dcb_entry(dcb_config_map, data):
+    for entry in dcb_config_map:
+        if entry['pci_addr'] == data.pci_addr:
+            entry['dscp2prio'] = data.dscp2prio
+            entry['name'] = data.name
+            entry['driver'] = data.driver
+            break
+    else:
+        new_entry = {}
+        new_entry['name'] = data.name
+        new_entry['pci_addr'] = data.pci_addr
+        new_entry['driver'] = data.driver
+        new_entry['dscp2prio'] = data.dscp2prio
+
+        dcb_config_map.append(new_entry)
+    return dcb_config_map
+
+
+def reset_dcb_map():
+    dcb_map = get_empty_dcb_map()
+    if dcb_map != []:
+        write_dcb_map(dcb_map)
+
+
 def get_sriov_map(pf_name=None):
     contents = get_file_data(SRIOV_CONFIG_FILE)
     sriov_map = yaml.safe_load(contents) if contents else []