GRE: Add tunnel-type erspan, l3 and teb

Add tunnel type
 - erspan
 - l3
 - teb (Transparent Ethernet Bridge)

By default L3 GRE interfaces cannot be bridged to a bridge interface.
Add the ability to change tunnel type.

set vpp interfaces gre gre2 tunnel-type 'teb'

4 files changed, 72 insertions, 7 deletions

diff --git a/interface-definitions/vpp.xml.in b/interface-definitions/vpp.xml.in
index 0718ba0fe..c946839db 100644
--- a/interface-definitions/vpp.xml.in
+++ b/interface-definitions/vpp.xml.in
@@ -180,6 +180,31 @@
               </valueHelp>
             </properties>
             <children>
+              <leafNode name="tunnel-type">
+                <properties>
+                  <help>GRE tunnel type</help>
+                  <completionHelp>
+                    <list>erspan l3 teb</list>
+                  </completionHelp>
+                  <valueHelp>
+                    <format>erspan</format>
+                    <description>Encapsulated Remote Switched Port Analyzer</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>l3</format>
+                    <description>Generic Routing Encapsulation (network layer)</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>teb</format>
+                    <description>L2 Transparent Ethernet Bridge</description>
+                  </valueHelp>
+                  <constraint>
+                    <regex>(erspan|l3|teb)</regex>
+                  </constraint>
+                  <constraintErrorMessage>Invalid encapsulation, must be one of: l3, teb or erspan</constraintErrorMessage>
+                </properties>
+                <defaultValue>l3</defaultValue>
+              </leafNode>
               #include <include/source-address-ipv4-ipv6.xml.i>
               #include <include/interface/tunnel-remote.xml.i>
               #include <include/kernel-interface-tun.xml.i>
diff --git a/python/vyos/vpp/interface/gre.py b/python/vyos/vpp/interface/gre.py
index 20a7ae9d4..65559f294 100644
--- a/python/vyos/vpp/interface/gre.py
+++ b/python/vyos/vpp/interface/gre.py
@@ -30,20 +30,58 @@ def show():
 
 
 class GREInterface:
-    def __init__(self, ifname, source_address, remote, kernel_interface: str = ''):
+    """
+    Class representing a GRE (Generic Routing Encapsulation) interface.
+
+    Attributes:
+        ifname (str): The interface name.
+        source_address (str): The source IP address for the GRE tunnel.
+        remote (str): The remote IP address for the GRE tunnel.
+        tunnel_type (str): The type of GRE tunnel. Defaults to 'l3'.
+        kernel_interface (str): The associated kernel interface. Defaults to an empty string.
+        instance (int): The instance number derived from the interface name.
+        vpp (VPPControl): An instance of the VPPControl class for interacting with the VPP API.
+    """
+
+    # Mapping of tunnel types https://github.com/FDio/vpp/blob/stable/2406/src/plugins/gre/gre.api#L25-L35
+    TUNNEL_TYPE_MAP = {
+        "l3": 0,
+        "teb": 1,
+        "erspan": 2,
+    }
+
+    def __init__(
+        self,
+        ifname,
+        source_address,
+        remote,
+        tunnel_type: str = 'l3',
+        kernel_interface: str = '',
+    ):
+        """
+        Initialize a GREInterface instance.
+
+        Args:
+            ifname (str): The interface name.
+            source_address (str): The source IP address for the GRE tunnel.
+            remote (str): The remote IP address for the GRE tunnel.
+            tunnel_type (str): The type of GRE tunnel. Defaults to 'l3'.
+            kernel_interface (str): The associated kernel interface. Defaults to an empty string.
+        """
         self.instance = int(ifname.removeprefix('gre'))
         self.ifname = ifname
         self.src_address = source_address
         self.dst_address = remote
+        self.tunnel_type = self.TUNNEL_TYPE_MAP[tunnel_type]
         self.kernel_interface = kernel_interface
         self.vpp = VPPControl()
 
     def add(self):
         """Create GRE interface
-        https://github.com/FDio/vpp/blob/stable/2306/src/plugins/gre/gre.api
+        https://github.com/FDio/vpp/blob/stable/2406/src/plugins/gre/gre.api
         Example:
             from vyos.vpp.interface import GREInterface
-            a = GREInterface(ifname='gre0', source_address='192.0.2.1', remote='203.0.113.25')
+            a = GREInterface(ifname='gre0', source_address='192.0.2.1', remote='203.0.113.25', tunnel_type='l3')
             a.add()
         """
         self.vpp.api.gre_tunnel_add_del(
@@ -52,6 +90,7 @@ class GREInterface:
                 'src': self.src_address,
                 'dst': self.dst_address,
                 'instance': self.instance,
+                'type': self.tunnel_type,
             },
         )
 
diff --git a/smoketest/scripts/cli/test_vpp.py b/smoketest/scripts/cli/test_vpp.py
index 582c41c68..ba0d0d728 100755
--- a/smoketest/scripts/cli/test_vpp.py
+++ b/smoketest/scripts/cli/test_vpp.py
@@ -552,7 +552,7 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         self.assertRegex(
             normalized_out,
             r'BondEthernet23\s+\d+\s+up',
-            "Interface BondEthernet23 is not in the expected state 'up'."
+            "Interface BondEthernet23 is not in the expected state 'up'.",
         )
 
         # set kernel interface
@@ -617,7 +617,7 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         self.assertRegex(
             normalized_out,
             r'BondEthernet23\s+\d+\s+up',
-            "Interface BondEthernet23 is not in the expected state 'up'."
+            "Interface BondEthernet23 is not in the expected state 'up'.",
         )
 
         # delete vpp kernel-interface vlan
diff --git a/src/conf_mode/vpp_interfaces_gre.py b/src/conf_mode/vpp_interfaces_gre.py
index feff0d6b5..4cb1a71ea 100644
--- a/src/conf_mode/vpp_interfaces_gre.py
+++ b/src/conf_mode/vpp_interfaces_gre.py
@@ -124,7 +124,7 @@ def verify(config):
         return None
 
     # source-address and remote are mandatory options
-    required_keys = {'source_address', 'remote'}
+    required_keys = {'source_address', 'remote', 'tunnel_type'}
     if not all(key in config for key in required_keys):
         missing_keys = required_keys - set(config.keys())
         raise ConfigError(
@@ -159,7 +159,8 @@ def apply(config):
     src_addr = config.get('source_address')
     dst_addr = config.get('remote')
     kernel_interface = config.get('kernel_interface', '')
-    i = GREInterface(ifname, src_addr, dst_addr, kernel_interface)
+    tunnel_type = config.get('tunnel_type')
+    i = GREInterface(ifname, src_addr, dst_addr, tunnel_type, kernel_interface)
     i.add()
 
     # Add kernel-interface (LCP) if interface is not exist