T7283: VPP add static NAT support (#24)

* T7283: VPP add static NAT support

Add static mapping NAT implementation

```
set vpp nat44 static rule 10 outbound-interface 'eth0'
set vpp nat44 static rule 10 inbound-interface 'eth1'
set vpp nat44 static rule 10 destination address 192.168.122.10    # optional, if not set outbound interface ip address is used
set vpp nat44 static rule 10 destination port 6545                 # optional
set vpp nat44 static rule 10 protocol tcp|udp|icmp|all             # optional, defaults to "all"
set vpp nat44 static rule 10 translation address 100.64.0.10
set vpp nat44 static rule 10 translation port 64010                # optional
```

* Improve help strings (Daniil Baturin)

---------

Co-authored-by: Daniil Baturin <daniil@baturin.org>

2 files changed, 88 insertions, 8 deletions

diff --git a/python/vyos/vpp/control_vpp.py b/python/vyos/vpp/control_vpp.py
index 2c81b2db2..9d45bbd91 100644
--- a/python/vyos/vpp/control_vpp.py
+++ b/python/vyos/vpp/control_vpp.py
@@ -160,6 +160,21 @@ class VPPControl:
                 return iface.sw_if_index
         return None
 
+    @_Decorators.api_call
+    def get_interface_name(self, index: int) -> str | None:
+        """Find interface name by interface index in VPP
+
+        Args:
+            index (int): interface index inside VPP
+
+        Returns:
+            str | None: Interface name or None (if was not found)
+        """
+        for iface in self.__vpp_api_client.api.sw_interface_dump():
+            if iface.sw_if_index == index:
+                return iface.interface_name
+        return None
+
     @_Decorators.check_retval
     @_Decorators.api_call
     def lcp_pair_add(
diff --git a/python/vyos/vpp/nat/nat44.py b/python/vyos/vpp/nat/nat44.py
index 47d0ced1d..985e5a583 100644
--- a/python/vyos/vpp/nat/nat44.py
+++ b/python/vyos/vpp/nat/nat44.py
@@ -86,38 +86,34 @@ class Nat44:
             is_add=False,
         )
 
-    # needs to check
     def add_nat44_interface_inside(self):
         """Add NAT44 interface"""
         self.vpp.api.nat44_interface_add_del_feature(
-            flags=1,
+            flags=0x20,
             sw_if_index=self.vpp.get_sw_if_index(self.interface_in),
             is_add=True,
         )
 
-    # needs to check
     def delete_nat44_interface_inside(self):
         """Delete NAT44 interface"""
         self.vpp.api.nat44_interface_add_del_feature(
-            flags=1,
+            flags=0x20,
             sw_if_index=self.vpp.get_sw_if_index(self.interface_in),
             is_add=False,
         )
 
-    # needs to check
     def add_nat44_interface_outside(self):
         """Add NAT44 interface"""
         self.vpp.api.nat44_interface_add_del_feature(
-            flags=0,
+            flags=0x10,
             sw_if_index=self.vpp.get_sw_if_index(self.interface_out),
             is_add=True,
         )
 
-    # needs to check
     def delete_nat44_interface_outside(self):
         """Delete NAT44 interface"""
         self.vpp.api.nat44_interface_add_del_feature(
-            flags=0,
+            flags=0x10,
             sw_if_index=self.vpp.get_sw_if_index(self.interface_out),
             is_add=False,
         )
@@ -149,3 +145,72 @@ class Nat44:
     def enable_ipfix(self):
         """Enable NAT44 IPFIX logging"""
         self.vpp.api.nat44_ei_ipfix_enable_disable(enable=True)
+
+
+class Nat44Static(Nat44):
+    def __init__(self):
+        self.vpp = VPPControl()
+
+    def add_inbound_interface(self, interface_in):
+        self.interface_in = interface_in
+        self.add_nat44_interface_inside()
+
+    def delete_inbound_interface(self, interface_in):
+        self.interface_in = interface_in
+        self.delete_nat44_interface_inside()
+
+    def add_outbound_interface(self, interface_out):
+        self.interface_out = interface_out
+        self.add_nat44_interface_outside()
+
+    def delete_outbound_interface(self, interface_out):
+        self.interface_out = interface_out
+        self.delete_nat44_interface_outside()
+
+    def add_nat44_static_mapping(
+        self,
+        iface_out,
+        local_ip,
+        external_ip,
+        local_port,
+        external_port,
+        protocol,
+        use_iface,
+    ):
+        """Add NAT44 static mapping"""
+        self.vpp.api.nat44_add_del_static_mapping_v2(
+            local_ip_address=local_ip,
+            external_ip_address=external_ip,
+            protocol=protocol,
+            local_port=local_port,
+            external_port=external_port,
+            flags=0x08 if not (protocol or local_port) else 0x00,
+            external_sw_if_index=(
+                self.vpp.get_sw_if_index(iface_out) if use_iface else 0xFFFFFFFF
+            ),
+            is_add=True,
+        )
+
+    def delete_nat44_static_mapping(
+        self,
+        iface_out,
+        local_ip,
+        external_ip,
+        local_port,
+        external_port,
+        protocol,
+        use_iface,
+    ):
+        """Delete NAT44 static mapping"""
+        self.vpp.api.nat44_add_del_static_mapping_v2(
+            local_ip_address=local_ip,
+            external_ip_address=external_ip,
+            protocol=protocol,
+            local_port=local_port,
+            external_port=external_port,
+            flags=0x08 if not (protocol or local_port) else 0x00,
+            external_sw_if_index=(
+                self.vpp.get_sw_if_index(iface_out) if use_iface else 0xFFFFFFFF
+            ),
+            is_add=False,
+        )