feat: smart interface detection — lists all interfaces, validates choice, auto-detects subnet mask

install.sh

@@ -21,6 +21,7 @@ CONFIG_SAVE="/root/.dnsmasq-setup.conf"
 # User-provided values (populated by prompts or saved config)
 IFACE=""; RANGE_START=""; RANGE_END=""; NETMASK=""
 LEASE_TIME=""; GATEWAY_IP=""; DNS_SERVERS=""
+SUBNET_MASK="255.255.255.0"  # auto-detected from interface
 
 # Detected values
 ZORAXY_MODE=""          # baremetal | docker | fresh
@@ -118,51 +119,97 @@ install_deps() {
 #  INTERACTIVE CONFIGURATION
 #==============================================================================
 
+# list_interfaces prints available physical/virtual interfaces with IPs.
+list_interfaces() {
+    echo ""
+    echo "  Available network interfaces:"
+    ip -o addr show 2>/dev/null | awk '/inet / && $2 != "lo" {
+        split($2, iface, "@"); name=iface[1]; ip=$4;
+        state=$(NF); gsub(/state /, "", state);
+        printf "    %-12s  %-18s  %s\n", name, ip, state
+    }' || true
+}
+
+# detect_defaults uses routing info to guess the primary interface.
 detect_defaults() {
-    # Auto-detect primary network interface (graceful fallback if ip route fails)
+    IFACE_DEFAULT=$(ip route get 1.1.1.1 2>/dev/null | awk '{print $5; exit}' | sed 's/@.*//' || true)
-    IFACE_DEFAULT=$(ip route get 1.1.1.1 2>/dev/null | awk '{print $5; exit}' || true)
     [ -z "$IFACE_DEFAULT" ] && IFACE_DEFAULT="eth0"
 
-    # Auto-detect gateway
     GATEWAY_DEFAULT=$(ip route get 1.1.1.1 2>/dev/null | awk '{print $3; exit}' || true)
-    [ -z "$GATEWAY_DEFAULT" ] && GATEWAY_DEFAULT="10.2.0.10"
 
-    # Auto-detect DNS from resolv.conf
     DNS_DEFAULT=$( (grep '^nameserver' /etc/resolv.conf 2>/dev/null || true) | awk '{print $2}' | tr '\n' ',' | sed 's/,$//')
     [ -z "$DNS_DEFAULT" ] && DNS_DEFAULT="1.1.1.1,8.8.8.8"
+
+    # Try to derive subnet from the selected interface's IP
+    local iface_ip iface_cidr
+    iface_ip=$(ip -o addr show "$IFACE_DEFAULT" 2>/dev/null | awk '/inet / {print $4; exit}' || true)
+    iface_cidr="${iface_ip#*/}"
+    case "$iface_cidr" in
+        24) SUBNET_MASK="255.255.255.0" ;;
+        16) SUBNET_MASK="255.255.0.0"   ;;
+        8)  SUBNET_MASK="255.0.0.0"     ;;
+        *)  SUBNET_MASK="255.255.255.0" ;;
+    esac
+}
+
+# validate_interface checks the chosen interface exists and is UP.
+validate_interface() {
+    local iface="$1"
+    if ! ip link show "$iface" >/dev/null 2>&1; then
+        err "Interface '$iface' does not exist."
+        return 1
+    fi
+    if ! ip link show "$iface" 2>/dev/null | grep -q "state UP"; then
+        warn "Interface '$iface' is DOWN. DHCP won't work until it's brought up."
+    fi
+    return 0
 }
 
 prompt_config() {
     echo ""
     echo -e "${BOLD}─────────────────────────────────────────${NC}"
-    echo -e "${BOLD}  Network Configuration${NC}"
+    echo -e "${BOLD}  Network Interface${NC}"
     echo -e "${BOLD}─────────────────────────────────────────${NC}"
-    echo ""
 
-    # Disable strict error handling during detection + prompts
-    # (ip route may fail, read may hit EOF without TTY)
     set +eo pipefail
     detect_defaults
     set -eo pipefail
 
-    # Network interface
+    # Show interfaces + let user choose
-    read -rp "  Network interface [$IFACE_DEFAULT]: " IFACE || true
+    list_interfaces
+
+    while true; do
+        echo ""
+        read -rp "  DHCP interface [$IFACE_DEFAULT]: " IFACE || true
         IFACE="${IFACE:-$IFACE_DEFAULT}"
+        if validate_interface "$IFACE"; then break; fi
+    done
+
+    # Detect gateway from the chosen interface if not already set
+    if [ -z "$GATEWAY_DEFAULT" ]; then
+        GATEWAY_DEFAULT="10.2.0.10"
+    fi
 
     # DHCP range
     echo ""
-    echo "  DHCP IP Range"
+    echo -e "${BOLD}─────────────────────────────────────────${NC}"
+    echo -e "${BOLD}  DHCP Range${NC}"
+    echo -e "${BOLD}─────────────────────────────────────────${NC}"
+
     read -rp "  Start IP   [10.2.0.100]: " RANGE_START || true
     RANGE_START="${RANGE_START:-10.2.0.100}"
     read -rp "  End IP     [10.2.0.150]: " RANGE_END || true
     RANGE_END="${RANGE_END:-10.2.0.150}"
-    read -rp "    Subnet mask [255.255.255.0]: " NETMASK || true
+    read -rp "  Subnet mask [$SUBNET_MASK]: " NETMASK || true
-    NETMASK="${NETMASK:-255.255.255.0}"
+    NETMASK="${NETMASK:-$SUBNET_MASK}"
     read -rp "  Lease time  [12h]: " LEASE_TIME || true
     LEASE_TIME="${LEASE_TIME:-12h}"
 
     # Gateway & DNS
     echo ""
+    echo -e "${BOLD}─────────────────────────────────────────${NC}"
+    echo -e "${BOLD}  Gateway & DNS${NC}"
+    echo -e "${BOLD}─────────────────────────────────────────${NC}"
     read -rp "  Gateway IP  [$GATEWAY_DEFAULT]: " GATEWAY_IP || true
     GATEWAY_IP="${GATEWAY_IP:-$GATEWAY_DEFAULT}"
     read -rp "  DNS servers (comma-separated) [$DNS_DEFAULT]: " DNS_SERVERS || true