feat: adding configurable gateway for DHCP server (#23)

Containerfile

@@ -1,13 +1,13 @@
-FROM docker.io/node:18.20.5 as base
+FROM docker.io/node:18.20.5 AS base
 RUN corepack enable \
     && yarn set version berry
 WORKDIR /app
 ENV NODE_OPTIONS=--openssl-legacy-provider
 
-FROM base as dev
+FROM base AS dev
 CMD exec /bin/bash -c "yarn install && yarn watch"
 
-FROM base as builder
+FROM base AS builder
 COPY ui/.yarnrc.yml .
 COPY ui/package.json .
 COPY ui/yarn.lock .
@@ -20,7 +20,7 @@ COPY ui/babel.config.js .
 COPY ui/vue.config.js .
 RUN yarn build
 
-FROM scratch as dist
+FROM scratch AS dist
 COPY imageroot imageroot
 COPY --from=builder /app/dist ui
 LABEL org.nethserver.rootfull=1

container/Containerfile

@@ -1,6 +1,6 @@
-FROM docker.io/debian:12.8-slim as base
+FROM docker.io/debian:12.8-slim AS base
 
-FROM base as build
+FROM base AS build
 # Setup image
 RUN apt-get update \
     && apt-get install -y build-essential
@@ -14,7 +14,7 @@ WORKDIR /tmp/dnsmasq
 # Build dnsmasq
 RUN make
 
-FROM base as dist
+FROM base AS dist
 # Copy built dnsmasq and configuration
 COPY --from=build /tmp/dnsmasq/src/dnsmasq /usr/local/sbin/dnsmasq
 COPY dnsmasq.conf /etc/dnsmasq.conf

imageroot/actions/configure-module/10validate

@@ -35,6 +35,7 @@ if request["dhcp-server"]["enabled"]:
     # check if start and end are in the same network being configured
     start = ipaddress.IPv4Address(request["dhcp-server"]["start"])
     end = ipaddress.IPv4Address(request["dhcp-server"]["end"])
+    gateway = ipaddress.IPv4Address(request["dhcp-server"]["gateway"])
     interface_network = next(interface for interface in interfaces if interface["name"] == request["interface"])
     start_found = False
     for address in interface_network["addresses"]:
@@ -48,6 +49,12 @@ if request["dhcp-server"]["enabled"]:
             end_found = True
             break
 
+    gateway_found = False
+    for address in interface_network["addresses"]:
+        if gateway in address["network"]:
+            gateway_found = True
+            break
+
     if not start_found:
         agent.set_status('validation-failed')
         json.dump([{'field':'dhcp-server.start', 'parameter':'dhcp-server.start','value': request['dhcp-server']['start'], 'error':'not_in_network'}], fp=sys.stdout)
@@ -64,6 +71,13 @@ if request["dhcp-server"]["enabled"]:
         json.dump([{'field':'dhcp-server.start', 'parameter':'dhcp-server.start','value': request['dhcp-server']['start'], 'error':'must_be_less_than_end'}], fp=sys.stdout)
         sys.exit(2)
 
+    if not gateway_found:
+        agent.set_status('validation-failed')
+        json.dump([{'field': 'dhcp-server.gateway', 'parameter': 'dhcp-server.gateway',
+                    'value': request["dhcp-server"]["gateway"],
+                    'error': 'not_in_network'}], fp=sys.stdout)
+        sys.exit(2)
+
 if request["dns-server"]["enabled"]:
     is_dns_bound = network.are_ports_53_bound() or bool(network.get_local_samba_dcs())
     # read config.json and determine if dns is used for this instance

imageroot/actions/configure-module/validate-input.json

@@ -27,6 +27,10 @@
                     "description": "Lease time in hours",
                     "type": "integer",
                     "minimum": 1
+                },
+                "gateway": {
+                    "description": "Gateway to be assigned to clients",
+                    "type": "string"
                 }
             },
             "if": {
@@ -43,14 +47,18 @@
                     },
                     "end": {
                         "format": "ipv4"
+                    },
+                    "gateway": {
+                        "format": "ipv4"
                     }
                 }
             },
             "required": [
                 "enabled",
                 "start",
                 "end",
-                "lease"
+                "lease",
+                "gateway"
             ]
         },
         "dns-server": {

imageroot/actions/get-configuration/10get

@@ -7,7 +7,6 @@
 
 import json
 import sys
-import agent
 import network
 
 config = json.load(open("config.json"))
@@ -17,6 +16,7 @@ if config["interface"] != "" and config["dhcp-server"]["start"] == "" and config
     interface = next(interface for interface in interfaces if interface["name"] == config["interface"])
     config["dhcp-server"]["start"] = str(interface["start"])
     config["dhcp-server"]["end"] = str(interface["end"])
+    config["dhcp-server"]["gateway"] = str(interface["gateway"])
 
 # we test if tcp/53 or udp/53 is bound to the interface, or local Samba DCs are present
 local_samba_dcs = network.get_local_samba_dcs()

imageroot/actions/get-configuration/validate-output.json

@@ -43,13 +43,26 @@
                     "description": "Lease time in hours",
                     "type": "integer",
                     "minimum": 1
+                },
+                "gateway": {
+                    "description": "Gateway to be assigned to clients",
+                    "type": "string",
+                    "oneOf": [
+                        {
+                            "format": "ipv4"
+                        },
+                        {
+                            "maxLength": 0
+                        }
+                    ]
                 }
             },
             "required": [
                 "enabled",
                 "start",
                 "end",
-                "lease"
+                "lease",
+                "gateway"
             ]
         },
         "dns-server": {

imageroot/bin/expand-config

@@ -21,7 +21,8 @@ except FileNotFoundError:
             "enabled": False,
             "start": "",
             "end": "",
-            "lease": 12
+            "lease": 12,
+            "gateway": "",
         },
         "dns-server": {
             "enabled": False,
@@ -45,6 +46,8 @@ with open("dnsmasq.d/00config.conf", "w") as file:
     # write dhcp-server configuration
     if config["dhcp-server"]["enabled"]:
         file.write("dhcp-range=set:default," + config["dhcp-server"]["start"] + "," + config["dhcp-server"]["end"] + "," + str(config["dhcp-server"]["lease"]) + "h\n")
+        if "gateway" in config["dhcp-server"] and config["dhcp-server"]["gateway"] != "":
+            file.write("dhcp-option=tag:default,option:router," + config["dhcp-server"]["gateway"] + "\n")
 
     # write dns-server configuration, if no local Samba DC is present
     if len(local_samba_dcs) > 0:

imageroot/pypkg/network.py

@@ -5,7 +5,6 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 #
 
-import sys
 import os
 import agent
 import ipaddress
@@ -41,8 +40,16 @@ def __format_interface(interface):
         "name": interface["ifname"],
         "addresses": [],
         "start": "",
-        "end": ""
+        "end": "",
+        "gateway": ""
     }
+    gateway = subprocess.run(["ip", "-4", "-j", "route", "show", "dev", interface["ifname"], "default"], check=True,
+                             capture_output=True, text=True).stdout
+    gateway = json.loads(gateway)
+    if len(gateway) > 0:
+        gateway = gateway[0]['gateway']
+    else:
+        gateway = None
     for address in interface["addr_info"]:
         if address["family"] == "inet":
             network = ipaddress.IPv4Network(address["local"] + "/" + str(address["prefixlen"]), strict=False)
@@ -53,6 +60,8 @@ def __format_interface(interface):
             # last address wins the start and end fields
             interface_data["start"] = network.network_address + 1
             interface_data["end"] = network.network_address + network.num_addresses - 2
+            if gateway is not None and ipaddress.IPv4Address(gateway) in network:
+                interface_data["gateway"] = gateway
 
     return interface_data
 

imageroot/update-module.d/20gateway_default

@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+
+#
+# Copyright (C) 2024 Nethesis S.r.l.
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+import json
+
+config = json.load(open('config.json'))
+
+if config['dhcp-server']['enabled']:
+    if 'gateway' not in config['dhcp-server']:
+        # the field is left empty, to avoid assigning a default value
+        # this is because if in any case the interface the dhcp-server is running
+        # has two or more ips, a default gateway might cause way too many issues
+        config['dhcp-server']['gateway'] = ''
+
+json.dump(config, fp=open('config.json', 'w'))

ui/.nvmrc

@@ -0,0 +1 @@
+v18.20.5

ui/public/i18n/en/translation.json

@@ -44,6 +44,8 @@
         "DHCP_end_label": "IP range end",
         "DHCP_lease_label": "Lease time",
         "DHCP_lease_hint": "Hours",
+        "DHCP_gateway_label": "Gateway",
+        "DHCP_gateway_hint": "Default gateway for the DHCP clients",
         "DNS_title": "DNS",
         "DNS_description": "Network names forward and cache service, listening on port 53.",
         "DNS_enable_label": "Enable DNS",
@@ -55,7 +57,8 @@
         "dns-server_format": "IPv4 format required",
         "dns-server_number_one_of": "IPv4 or IPv6 required",
         "dns_server_is_running": "A DNS server is currently running",
-        "dns_server_is_running_description": "You cannot enable the DNS feature because a DNS server is already active on this node. Another application, such as Samba DC, might be using the DNS port."
+        "dns_server_is_running_description": "You cannot enable the DNS feature because a DNS server is already active on this node. Another application, such as Samba DC, might be using the DNS port.",
+        "not_in_network": "Address provided is not in the network of the selected interface"
     },
     "dns_records": {
         "title": "DNS records",

ui/src/views/Settings.vue

@@ -139,6 +139,16 @@
                     ref="dhcpLeaseField"
                   >
                   </cv-text-input>
+                  <cv-text-input
+                    :label="$t('settings.DHCP_gateway_label')"
+                    :helper-text="$t('settings.DHCP_gateway_hint')"
+                    v-model="dhcpGatewayField"
+                    :disabled="
+                      loading.getConfiguration || loading.configureModule
+                    "
+                    :invalid-message="error.dhcpGatewayField"
+                    ref="dhcpGatewayField"
+                  />
                 </div>
                 <NsButton
                   kind="secondary"
@@ -269,6 +279,7 @@ export default {
       dhcpStartField: "",
       dhcpEndField: "",
       dhcpLeaseField: 12,
+      dhcpGatewayField: "",
       is_dns_bound: false,
       is_dns_enabled: false,
       dnsEnableField: false,
@@ -288,6 +299,7 @@ export default {
         dhcpStartField: "",
         dhcpEndField: "",
         dhcpLeaseField: "",
+        dhcpGatewayField: "",
         dnsEnableField: "",
         dnsPrimaryField: "",
         dnsSecondaryField: "",
@@ -424,6 +436,7 @@ export default {
       this.dhcpStartField = dhcp_server["start"];
       this.dhcpEndField = dhcp_server["end"];
       this.dhcpLeaseField = dhcp_server["lease"].toString();
+      this.dhcpGatewayField = dhcp_server["gateway"];
       this.dnsEnableField = dns_server["enabled"];
       this.dnsPrimaryField = dns_server["primary-server"];
       this.dnsSecondaryField = dns_server["secondary-server"];
@@ -467,6 +480,14 @@ export default {
             isValidationOk = false;
           }
         }
+        if (!this.dhcpGatewayField) {
+          this.error.dhcpGatewayField = this.$t("common.required");
+
+          if (isValidationOk) {
+            this.focusElement("dhcpGatewayField");
+            isValidationOk = false;
+          }
+        }
       }
       if (this.dnsEnableField && !this.dnsPrimaryField) {
         this.error.dnsPrimaryField = this.$t("common.required");
@@ -498,6 +519,11 @@ export default {
             "settings." + validationError.error
           );
         }
+        if (validationError.field === "dhcp-server.gateway") {
+          this.error.dhcpGatewayField = this.$t(
+            "settings." + validationError.error
+          );
+        }
         if (validationError.field === "dns-server.primary-server") {
           this.error.dnsPrimaryField = this.$t(
             "settings." + validationError.error
@@ -548,6 +574,7 @@ export default {
               start: this.dhcpStartField,
               end: this.dhcpEndField,
               lease: parseInt(this.dhcpLeaseField),
+              gateway: this.dhcpGatewayField,
             },
             "dns-server": {
               enabled: this.dnsEnableField,