From cbc25c0dad7058d30e7d4e11b21fb632f7131ffe Mon Sep 17 00:00:00 2001
From: Oleksandr Ivantsiv <oivantsiv@nvidia.com>
Date: Fri, 31 May 2024 19:54:52 +0000
Subject: [PATCH] [dhcp_server] Fix the issue with "kea-dhcp4.conf" file
 generation for Smart Switch.

---
 .../dhcp_utilities/dhcpservd/dhcp_cfggen.py                | 7 ++++---
 src/sonic-dhcp-utilities/tests/test_data/kea-dhcp4.conf.j2 | 1 +
 src/sonic-dhcp-utilities/tests/test_dhcp_cfggen.py         | 1 +
 src/sonic-dhcp-utilities/tests/test_smart_switch.py        | 1 +
 4 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/sonic-dhcp-utilities/dhcp_utilities/dhcpservd/dhcp_cfggen.py b/src/sonic-dhcp-utilities/dhcp_utilities/dhcpservd/dhcp_cfggen.py
index eb7ae34d852f..c79d6225d04f 100755
--- a/src/sonic-dhcp-utilities/dhcp_utilities/dhcpservd/dhcp_cfggen.py
+++ b/src/sonic-dhcp-utilities/dhcp_utilities/dhcpservd/dhcp_cfggen.py
@@ -90,7 +90,7 @@ def generate(self):
         port_ips, used_ranges = self._parse_port(port_ipv4, dhcp_interfaces, dhcp_members, ranges)
         customized_options = self._parse_customized_options(customized_options_ipv4)
         render_obj, enabled_dhcp_interfaces, used_options, subscribe_table = \
-            self._construct_obj_for_template(dhcp_server_ipv4, port_ips, hostname, customized_options)
+            self._construct_obj_for_template(dhcp_server_ipv4, port_ips, hostname, customized_options, smart_switch)
 
         if smart_switch:
             subscribe_table |= set(SMART_SWITCH_CHECKER)
@@ -175,7 +175,7 @@ def _parse_port_map_alias(self):
         for pc_name in pc_table.keys():
             self.port_alias_map[pc_name] = pc_name
 
-    def _construct_obj_for_template(self, dhcp_server_ipv4, port_ips, hostname, customized_options):
+    def _construct_obj_for_template(self, dhcp_server_ipv4, port_ips, hostname, customized_options, smart_switch=False):
         subnets = []
         client_classes = []
         enabled_dhcp_interfaces = set()
@@ -223,8 +223,9 @@ def _construct_obj_for_template(self, dhcp_server_ipv4, port_ips, hostname, cust
                                 "condition": "substring(relay4[1].hex, -{}, {}) == '{}'".format(class_len, class_len,
                                                                                                 client_class)
                             })
+
                     subnet_obj = {
-                        "id": dhcp_interface_name.replace("Vlan", ""),
+                        "id": 0 if smart_switch else dhcp_interface_name.replace("Vlan", ""),
                         "subnet": str(ipaddress.ip_network(dhcp_interface_ip, strict=False)),
                         "pools": pools,
                         "gateway": dhcp_config["gateway"],
diff --git a/src/sonic-dhcp-utilities/tests/test_data/kea-dhcp4.conf.j2 b/src/sonic-dhcp-utilities/tests/test_data/kea-dhcp4.conf.j2
index 082cbca14dd5..f5f7a9b054f0 100644
--- a/src/sonic-dhcp-utilities/tests/test_data/kea-dhcp4.conf.j2
+++ b/src/sonic-dhcp-utilities/tests/test_data/kea-dhcp4.conf.j2
@@ -42,6 +42,7 @@
     {%- if add_subnet_preceding_comma.flag -%},{%- endif -%}
     {%- set _dummy = add_subnet_preceding_comma.update({'flag': True}) %}
             {
+                "id": {{ subnet_info["id"] }},
                 "subnet": "{{ subnet_info["subnet"] }}",
                 "pools": [
     {%- set add_pool_preceding_comma = { 'flag': False } %}
diff --git a/src/sonic-dhcp-utilities/tests/test_dhcp_cfggen.py b/src/sonic-dhcp-utilities/tests/test_dhcp_cfggen.py
index 723731839649..3548e39c1435 100644
--- a/src/sonic-dhcp-utilities/tests/test_dhcp_cfggen.py
+++ b/src/sonic-dhcp-utilities/tests/test_dhcp_cfggen.py
@@ -42,6 +42,7 @@
         },
         "subnet4": [
             {
+                "id": 1000,
                 "subnet": "192.168.0.0/21",
                 "pools": [
                     {
diff --git a/src/sonic-dhcp-utilities/tests/test_smart_switch.py b/src/sonic-dhcp-utilities/tests/test_smart_switch.py
index 0347d5df2f6d..f8de9868b3d0 100644
--- a/src/sonic-dhcp-utilities/tests/test_smart_switch.py
+++ b/src/sonic-dhcp-utilities/tests/test_smart_switch.py
@@ -35,6 +35,7 @@
         },
         "subnet4": [
             {
+                "id": 0,
                 "subnet": "169.254.200.0/24",
                 "pools": [
                     {