VPP: T1797: Improved VPP support

- added ability to add/remove interfaces without system reboot
- added `attempts` and `interval` to the VPP API connection. This is helpful in
case of high system load or when VPP was just started and API is not yet
available.
- added exceptions to API calls. This allows handling errors in communication
with API properly in conf-mode scripts.
- fixed PCI address search in VPP to match Linux kernel and ethtool style
- fixed systemd daemons control - first reload, then restart
- removed debug prints
- removed `vm.nr_hugepages` configuration. It is not required now but increases
RAM requirements a lot.

2 files changed, 108 insertions, 19 deletions

diff --git a/python/vyos/vpp.py b/python/vyos/vpp.py
index d60ecc1b3..cf0d27eb1 100644
--- a/python/vyos/vpp.py
+++ b/python/vyos/vpp.py
@@ -13,20 +13,57 @@
 # You should have received a copy of the GNU Lesser General Public
 # License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
+from functools import wraps
+from pathlib import Path
 from re import search as re_search, MULTILINE as re_M
+from time import sleep
 
 from vpp_papi import VPPApiClient
+from vpp_papi import VPPIOError
 
 
 class VPPControl:
     """Control VPP network stack
     """
 
-    def __init__(self) -> None:
+    class _Decorators:
+        """Decorators for VPPControl
+        """
+
+        @classmethod
+        def api_call(cls, decorated_func):
+
+            @wraps(decorated_func)
+            def api_safe_wrapper(cls, *args, **kwargs):
+                if not cls.vpp_api_client.transport.connected:
+                    raise VPPIOError(2, 'VPP API is not connected')
+                return decorated_func(cls, *args, **kwargs)
+
+            return api_safe_wrapper
+
+    def __init__(self, attempts: int = 5, interval: int = 1000) -> None:
         """Create VPP API connection
+
+        Args:
+            attempts (int, optional): attempts to connect. Defaults to 5.
+            interval (int, optional): interval between attempts in ms. Defaults to 1000.
+
+        Raises:
+            VPPIOError: Connection to API cannot be established
         """
         self.vpp_api_client = VPPApiClient()
-        self.vpp_api_client.connect('vpp-vyos')
+        # connect with interval
+        while attempts:
+            try:
+                attempts -= 1
+                self.vpp_api_client.connect('vpp-vyos')
+                break
+            except (ConnectionRefusedError, FileNotFoundError) as err:
+                print(f'VPP API connection timeout: {err}')
+                sleep(interval / 1000)
+        # raise exception if connection was not successful in the end
+        if not self.vpp_api_client.transport.connected:
+            raise VPPIOError(2, 'Cannot connect to VPP API')
 
     def __del__(self) -> None:
         """Disconnect from VPP API (destructor)
@@ -36,8 +73,10 @@ class VPPControl:
     def disconnect(self) -> None:
         """Disconnect from VPP API
         """
-        self.vpp_api_client.disconnect()
+        if self.vpp_api_client.transport.connected:
+            self.vpp_api_client.disconnect()
 
+    @_Decorators.api_call
     def cli_cmd(self, command: str, return_output: bool = False) -> str:
         """Send raw CLI command
 
@@ -53,6 +92,7 @@ class VPPControl:
             return cli_answer.reply
         return ''
 
+    @_Decorators.api_call
     def get_mac(self, ifname: str) -> str:
         """Find MAC address by interface name in VPP
 
@@ -67,6 +107,7 @@ class VPPControl:
                 return iface.l2_address.mac_string
         return ''
 
+    @_Decorators.api_call
     def get_sw_if_index(self, ifname: str) -> int | None:
         """Find interface index by interface name in VPP
 
@@ -81,6 +122,7 @@ class VPPControl:
                 return iface.sw_if_index
         return None
 
+    @_Decorators.api_call
     def lcp_pair_add(self, iface_name_vpp: str, iface_name_kernel: str) -> None:
         """Create LCP interface pair between VPP and kernel
 
@@ -95,6 +137,7 @@ class VPPControl:
                 sw_if_index=iface_index,
                 host_if_name=iface_name_kernel)
 
+    @_Decorators.api_call
     def lcp_pair_del(self, iface_name_vpp: str, iface_name_kernel: str) -> None:
         """Delete LCP interface pair between VPP and kernel
 
@@ -109,6 +152,7 @@ class VPPControl:
                 sw_if_index=iface_index,
                 host_if_name=iface_name_kernel)
 
+    @_Decorators.api_call
     def iface_rxmode(self, iface_name: str, rx_mode: str) -> None:
         """Set interface rx-mode in VPP
 
@@ -127,6 +171,7 @@ class VPPControl:
         self.vpp_api_client.api.sw_interface_set_rx_mode(
             sw_if_index=iface_index, mode=modes_dict[rx_mode])
 
+    @_Decorators.api_call
     def get_pci_addr(self, ifname: str) -> str:
         """Find PCI address of interface by interface name in VPP
 
@@ -147,4 +192,30 @@ class VPPControl:
             return ''
 
         address = re_obj.groupdict().get('address', '')
-        return address
+
+        # we need to modify address to math kernel style
+        # for example: 0000:06:14.00 -> 0000:06:14.0
+        address_chunks: list[str] | Any = address.split('.')
+        address_normalized: str = f'{address_chunks[0]}.{int(address_chunks[1])}'
+
+        return address_normalized
+
+
+class HostControl:
+    """Control Linux host
+    """
+
+    def pci_rescan(self, address: str = '') -> None:
+        """Rescan PCI device by removing it and rescan PCI bus
+
+        If PCI address is not defined - just rescan PCI bus
+
+        Args:
+            address (str, optional): PCI address of device. Defaults to ''.
+        """
+        if address:
+            device_file = Path(f'/sys/bus/pci/devices/{address}/remove')
+            if device_file.exists():
+                device_file.write_text('1')
+        rescan_file = Path('/sys/bus/pci/rescan')
+        rescan_file.write_text('1')
diff --git a/src/conf_mode/vpp.py b/src/conf_mode/vpp.py
index 54ea54852..25fe159f8 100755
--- a/src/conf_mode/vpp.py
+++ b/src/conf_mode/vpp.py
@@ -20,6 +20,7 @@ from re import search as re_search, MULTILINE as re_M
 
 from vyos.config import Config
 from vyos.configdict import dict_merge
+from vyos.configdict import node_changed
 from vyos.ifconfig import Section
 from vyos.ifconfig import EthernetIf
 from vyos.ifconfig import interface
@@ -31,6 +32,7 @@ from vyos.xml import defaults
 from vyos import ConfigError
 from vyos import airbag
 from vyos.vpp import VPPControl
+from vyos.vpp import HostControl
 
 airbag.enable()
 
@@ -53,7 +55,6 @@ def _get_pci_address_by_interface(iface) -> str:
     # use VPP - maybe interface already attached to it
     vpp_control = VPPControl()
     pci_addr = vpp_control.get_pci_addr(iface)
-    vpp_control.disconnect()
     if pci_addr:
         return pci_addr
     # return empty string if address was not found
@@ -69,8 +70,20 @@ def get_config(config=None):
 
     base = ['vpp']
     base_ethernet = ['interfaces', 'ethernet']
+
+    # find interfaces removed from VPP
+    removed_ifaces = []
+    tmp = node_changed(conf, base + ['interface'])
+    if tmp:
+        for removed_iface in tmp:
+            pci_address: str = _get_pci_address_by_interface(removed_iface)
+            removed_ifaces.append({
+                'iface_name': removed_iface,
+                'iface_pci_addr': pci_address
+            })
+
     if not conf.exists(base):
-        return None
+        return {'removed_ifaces': removed_ifaces}
 
     config = conf.get_config_dict(base,
                                   get_first_key=True,
@@ -97,12 +110,15 @@ def get_config(config=None):
     config['other_interfaces'] = conf.get_config_dict(base_ethernet, key_mangling=('-', '_'),
                                      get_first_key=True, no_tag_node_value_mangle=True)
 
+    if removed_ifaces:
+        config['removed_ifaces'] = removed_ifaces
+
     return config
 
 
 def verify(config):
     # bail out early - looks like removal from running config
-    if not config:
+    if not config or (len(config) == 1 and 'removed_ifaces' in config):
         return None
 
     if 'interface' not in config:
@@ -114,7 +130,7 @@ def verify(config):
 
 
 def generate(config):
-    if not config:
+    if not config or (len(config) == 1 and 'removed_ifaces' in config):
         # Remove old config and return
         service_conf.unlink(missing_ok=True)
         return None
@@ -126,22 +142,24 @@ def generate(config):
 
 
 def apply(config):
-    if not config:
-        print(f'systemctl stop {service_name}.service')
+    if not config or (len(config) == 1 and 'removed_ifaces' in config):
         call(f'systemctl stop {service_name}.service')
-        return
     else:
-        print(f'systemctl restart {service_name}.service')
+        call('systemctl daemon-reload')
         call(f'systemctl restart {service_name}.service')
 
-    call('systemctl daemon-reload')
+    for iface in config.get('removed_ifaces', []):
+        HostControl().pci_rescan(iface['iface_pci_addr'])
 
-    call('sudo sysctl -w vm.nr_hugepages=4096')
-    vpp_control = VPPControl()
-    for iface, _ in config['interface'].items():
-        # Create lcp
-        if iface not in Section.interfaces():
-            vpp_control.lcp_pair_add(iface, iface)
+    if 'interface' in config:
+        # connect to VPP
+        # must be performed multiple attempts because API is not available
+        # immediately after the service restart
+        vpp_control = VPPControl(attempts=20, interval=500)
+        for iface, _ in config['interface'].items():
+            # Create lcp
+            if iface not in Section.interfaces():
+                vpp_control.lcp_pair_add(iface, iface)
 
         # update interface config
         #e = EthernetIf(iface)