openwrt · pgaufillet · Apr 6, 2026
diff --git a/net/lease-sync/Makefile b/net/lease-sync/Makefile
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2025-2026 Pierre Gaufillet <pierre.gaufillet@bergamote.eu>
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=lease-sync
+PKG_VERSION:=1.1.0
+PKG_RELEASE:=1
+
+PKG_SOURCE_PROTO:=git
+PKG_SOURCE_URL:=https://github.com/pgaufillet/lease-sync.git
+PKG_SOURCE_VERSION:=v1.1.0
+PKG_MIRROR_HASH:=3fcf2cb2eeb20ba5171c35a8d431db752a645dc50f9474f6f803e0ada5a2d28e
+
+PKG_MAINTAINER:=Pierre Gaufillet <pierre.gaufillet@bergamote.eu>
+PKG_LICENSE:=GPL-2.0-or-later
+PKG_LICENSE_FILES:=LICENSE
+
+PKG_BUILD_PARALLEL:=1
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/lease-sync
+  SECTION:=net
+  CATEGORY:=Network
+  SUBMENU:=IP Addresses and Names
+  TITLE:=DHCP Lease Synchronization Daemon
+  URL:=https://github.com/pgaufillet/lease-sync
+  DEPENDS:=+libubus +libubox +libopenssl +dnsmasq
+endef
+
+define Package/lease-sync/description
+  High-availability DHCP lease synchronization daemon for dnsmasq.
+  Enables active/active HA clusters by synchronizing DHCP leases
+  between multiple dnsmasq instances via ubus and UDP.
+endef
+
+define Package/lease-sync/conffiles
+/etc/config/lease-sync
+/etc/lease-sync/
+endef
+
+define Build/Compile
+	$(MAKE) -C $(PKG_BUILD_DIR)/daemon \
+		CC="$(TARGET_CC)" \
+		CFLAGS="$(TARGET_CFLAGS) $(TARGET_CPPFLAGS)" \
+		LDFLAGS="$(TARGET_LDFLAGS)" \
+		LIBS="-lubus -lubox -lssl -lcrypto" \
+		STATEDIR="/etc/lease-sync"
+endef
+
+define Package/lease-sync/install
+	$(INSTALL_DIR) $(1)/usr/sbin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/daemon/lease-sync $(1)/usr/sbin/
+
+	$(INSTALL_DIR) $(1)/etc/init.d
+	$(INSTALL_BIN) ./files/lease-sync.init $(1)/etc/init.d/lease-sync
+
+	$(INSTALL_DIR) $(1)/etc/config
+	$(INSTALL_CONF) ./files/lease-sync.config $(1)/etc/config/lease-sync
+
+	$(INSTALL_DIR) $(1)/etc/lease-sync
+
+	$(INSTALL_DIR) $(1)/etc/hotplug.d/dhcp
+	$(INSTALL_BIN) ./files/lease-sync.hotplug $(1)/etc/hotplug.d/dhcp/50-lease-sync
+
+endef
+
+define Package/lease-sync/prerm
+#!/bin/sh
+if [ -z "$${IPKG_INSTROOT}" ]; then
+	/etc/init.d/lease-sync stop >/dev/null 2>&1
+	/etc/init.d/lease-sync disable >/dev/null 2>&1
+fi
+exit 0
+endef
+
+define Package/lease-sync/postinst
+#!/bin/sh
+[ -n "$${IPKG_INSTROOT}" ] || {
+	/etc/init.d/lease-sync enable
+	echo "NOTE: Restart dnsmasq to activate the DHCP hotplug handler:"
+	echo "  /etc/init.d/dnsmasq restart"
+}
+exit 0
+endef
+
+$(eval $(call BuildPackage,lease-sync))
diff --git a/net/lease-sync/files/lease-sync.config b/net/lease-sync/files/lease-sync.config
@@ -0,0 +1,12 @@
+config lease-sync 'config'
+	option enabled '0'
+	option node_id ''
+	option sync_port '5378'
+	option sync_interval '30'
+	option peer_timeout '120'
+	option persist_interval '60'
+	option log_level '2'
+
+# Example peer configuration
+# config peer
+#	option address '192.168.1.2'
diff --git a/net/lease-sync/files/lease-sync.hotplug b/net/lease-sync/files/lease-sync.hotplug
@@ -0,0 +1,112 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2025-2026 Pierre Gaufillet <pierre.gaufillet@bergamote.eu>
+#
+# DHCP Lease Event Handler for lease-sync
+# This hotplug script publishes DHCP events to ubus for the lease-sync daemon
+# Installed to: /etc/hotplug.d/dhcp/50-lease-sync
+
+# Only process DHCP lease events
+[ -n "$ACTION" ] || exit 0
+
+# Configuration
+UBUS_EVENT="dhcp.lease"
+LOG_TAG="lease-sync-hotplug"
+NODE_ID_FILE="/etc/lease-sync/node-id"
+
+# Logging function
+log() {
+    logger -t "$LOG_TAG" -p "daemon.$1" "$2"
+}
+
+# Get or generate node ID
+get_node_id() {
+    if [ -f "$NODE_ID_FILE" ]; then
+        cat "$NODE_ID_FILE"
+    else
+        cat /sys/class/net/br-lan/address 2>/dev/null || hostname
+    fi
+}
+
+# Sanitize a string for safe JSON embedding.
+# Escapes backslash and double-quote characters to prevent injection.
+sanitize_json() {
+    printf '%s' "$1" | sed 's/\\/\\\\/g; s/"/\\"/g'
+}
+
+# Build JSON payload for ubus event
+build_lease_json() {
+    local json='{'
+
+    # Map hotplug ACTION to lease-sync action
+    case "$ACTION" in
+        add) json="${json}\"action\":\"add\"" ;;
+        remove) json="${json}\"action\":\"del\"" ;;
+        update) json="${json}\"action\":\"old\"" ;;
+        *) return 1 ;;
+    esac
+
+    # Required fields from hotplug environment
+    # (HOSTNAME is untrusted DHCP client input — must sanitize)
+    [ -n "$IPADDR" ] && json="${json},\"ip\":\"$IPADDR\""
+    [ -n "$MACADDR" ] && json="${json},\"mac\":\"$MACADDR\""
+    [ -n "$HOSTNAME" ] && json="${json},\"hostname\":\"$(sanitize_json "$HOSTNAME")\""
+
+    # Node identification
+    json="${json},\"node_id\":\"$(sanitize_json "$(get_node_id)")\""
+    json="${json},\"timestamp\":$(date +%s)"
+
+    # Lease timing (from dnsmasq environment, validated as numeric)
+    case "$DNSMASQ_LEASE_EXPIRES" in
+        ''|*[!0-9]*) ;;
+        *) json="${json},\"expires\":$DNSMASQ_LEASE_EXPIRES" ;;
+    esac
+    case "$DNSMASQ_TIME_REMAINING" in
+        ''|*[!0-9]*) ;;
+        *) json="${json},\"time_remaining\":$DNSMASQ_TIME_REMAINING" ;;
+    esac
+    case "$DNSMASQ_LEASE_LENGTH" in
+        ''|*[!0-9]*) ;;
+        *) json="${json},\"lease_length\":$DNSMASQ_LEASE_LENGTH" ;;
+    esac
+
+    # Client identification
+    [ -n "$DNSMASQ_CLIENT_ID" ] && json="${json},\"client_id\":\"$DNSMASQ_CLIENT_ID\""
+    [ -n "$DNSMASQ_INTERFACE" ] && json="${json},\"interface\":\"$DNSMASQ_INTERFACE\""
+
+    # IPv6 specific fields (IAID may have "T" prefix for temporary addresses)
+    if [ -n "$DNSMASQ_IAID" ]; then
+        local iaid_num
+        iaid_num=$(echo "$DNSMASQ_IAID" | sed 's/^T//')
+        case "$iaid_num" in
+            ''|*[!0-9]*) log err "Invalid DNSMASQ_IAID='$DNSMASQ_IAID', skipping" ;;
+            *)
+                json="${json},\"iaid\":$iaid_num"
+                if echo "$DNSMASQ_IAID" | grep -q "^T"; then
+                    json="${json},\"is_temporary\":1"
+                else
+                    json="${json},\"is_temporary\":0"
+                fi
+                ;;
+        esac
+    fi
+
+    json="${json}}"
+    echo "$json"
+}
+
+# Publish event to ubus
+case "$ACTION" in
+    add|remove|update)
+        [ -z "$IPADDR" ] && exit 0
+
+        payload=$(build_lease_json)
+        if ubus send "$UBUS_EVENT" "$payload" 2>/dev/null; then
+            log info "$ACTION event for $IPADDR published"
+        else
+            log err "Failed to publish $ACTION event for $IPADDR"
+        fi
+        ;;
+esac
+
+exit 0
diff --git a/net/lease-sync/files/lease-sync.init b/net/lease-sync/files/lease-sync.init
@@ -0,0 +1,104 @@
+#!/bin/sh /etc/rc.common
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) 2025-2026 Pierre Gaufillet <pierre.gaufillet@bergamote.eu>
+# lease-sync daemon init script for OpenWrt (procd)
+
+START=99
+STOP=10
+
+USE_PROCD=1
+
+PROG=/usr/sbin/lease-sync
+CONF=/etc/lease-sync/config
+
+start_service() {
+    # Ensure configuration directory exists
+    [ -d /etc/lease-sync ] || mkdir -p /etc/lease-sync
+    [ -d /var/lib/lease-sync ] || mkdir -p /var/lib/lease-sync
+
+    # Generate configuration from UCI
+    . /lib/functions.sh
+    config_load lease-sync
+
+    local enabled sync_port sync_interval persist_interval peer_timeout log_level node_id
+    config_get_bool enabled config enabled 0
+
+    # If disabled in UCI, don't start
+    [ "$enabled" -eq 0 ] && {
+        logger -t lease-sync -p daemon.info "lease-sync disabled in UCI configuration"
+        return 0
+    }
+
+    config_get sync_port config sync_port "5378"
+    config_get sync_interval config sync_interval "30"
+    config_get persist_interval config persist_interval "60"
+    config_get peer_timeout config peer_timeout "120"
+    config_get log_level config log_level "2"
+    config_get node_id config node_id ""
+
+    # Generate flat configuration file
+    logger -t lease-sync -p daemon.info "Generating configuration from UCI"
+
+    cat > "$CONF" <<EOF
+# Auto-generated from /etc/config/lease-sync
+# Do not edit - changes will be overwritten
+# Edit /etc/config/lease-sync instead
+
+sync_port=$sync_port
+sync_interval=$sync_interval
+persist_interval=$persist_interval
+peer_timeout=$peer_timeout
+log_level=$log_level
+EOF
+
+    # Add node_id if configured
+    [ -n "$node_id" ] && echo "node_id=$node_id" >> "$CONF"
+
+    # Add peers from UCI (list option)
+    add_peer() {
+        echo "peer=$1" >> "$CONF"
+    }
+    config_list_foreach config peer add_peer
+
+    logger -t lease-sync -p daemon.info "Configuration generated with $(grep -c '^peer=' "$CONF" 2>/dev/null || echo 0) peers"
+
+    procd_open_instance lease-sync
+    procd_set_param command "$PROG" -c "$CONF"
+
+    # Respawn settings
+    procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
+
+    # File descriptor limits
+    procd_set_param limits nofile="1024 1024"
+
+    # Standard streams
+    procd_set_param stdout 1
+    procd_set_param stderr 1
+
+    # Use syslog for logging
+    procd_set_param syslog 1
+
+    procd_close_instance
+
+    logger -t lease-sync -p daemon.info "Starting lease-sync daemon"
+}
+
+stop_service() {
+    logger -t lease-sync -p daemon.info "Stopping lease-sync daemon"
+}
+
+service_triggers() {
+    # Reload on network changes
+    procd_add_reload_trigger "network"
+
+    # Watch configuration file for changes
+    procd_add_reload_trigger "lease-sync"
+}
+
+# lease-sync does not support SIGHUP config reload, so reload_service()
+# performs a full restart (stop + start). Brief sync gap during restart.
+reload_service() {
+    logger -t lease-sync -p daemon.info "Restarting lease-sync daemon (full restart, no SIGHUP support)"
+    stop
+    start
+}