Adding support for DSCP configuration (#9)

Support dscp configuration using os-net-config templates. It uses
pyroute2 modules to send/receive, encode/decode the netlink messages.
The persistence of the configuration is done with dcb_config.service

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 []