feat: adds gateway detection

Author: robgonnella

Cargo.lock

@@ -22,7 +22,6 @@ ignored = ["prettytable-rs"]
 
 [dependencies]
 clap = { version = "^4.5", features = ["derive"] }
-pnet = "^0.35"
 prettytable-rs = "^0.10"
 color-eyre = "0.6.5"
 log = "^0.4"

cli/Cargo.toml

@@ -244,9 +244,9 @@ sudo r-lancli --debug
 +---------------+----------+-------------------+------------------------+
 | IP            | HOSTNAME | MAC               | VENDOR                 |
 +---------------+----------+-------------------+------------------------+
-| 192.168.1.1   | router   | aa:bb:cc:dd:ee:ff | Netgear                |
-| 192.168.1.100 | laptop   | 11:22:33:44:55:66 | Apple, Inc.            |
-| 192.168.1.150 |          | 99:88:77:66:55:44 | Samsung Electronics    |
+| 192.168.1.1 [GTWY] | router   | aa:bb:cc:dd:ee:ff | Netgear                |
+| 192.168.1.100      | laptop   | 11:22:33:44:55:66 | Apple, Inc.            |
+| 192.168.1.150      |          | 99:88:77:66:55:44 | Samsung Electronics    |
 +---------------+----------+-------------------+------------------------+
 ```
 
@@ -256,8 +256,8 @@ sudo r-lancli --debug
 +---------------+----------+-------------------+------------------------+-------------+
 | IP            | HOSTNAME | MAC               | VENDOR                 | OPEN_PORTS  |
 +---------------+----------+-------------------+------------------------+-------------+
-| 192.168.1.1   | router   | aa:bb:cc:dd:ee:ff | Netgear                | 22, 80, 443 |
-| 192.168.1.100 | laptop   | 11:22:33:44:55:66 | Apple, Inc.            | 22, 5900    |
+| 192.168.1.1 [GTWY] | router   | aa:bb:cc:dd:ee:ff | Netgear                | 22, 80, 443 |
+| 192.168.1.100      | laptop   | 11:22:33:44:55:66 | Apple, Inc.            | 22, 5900    |
 +---------------+----------+-------------------+------------------------+-------------+
 ```
 
@@ -271,6 +271,7 @@ sudo r-lancli --debug
     "mac": "aa:bb:cc:dd:ee:ff",
     "vendor": "Netgear",
     "is_current_host": false,
+    "is_gateway": true,
     "open_ports": [
       { "id": 22, "service": "ssh" },
       { "id": 80, "service": "http" },

cli/README.md

@@ -17,7 +17,7 @@ use core::time;
 use itertools::Itertools;
 use r_lanlib::{
     error::Result as LibResult,
-    network::{self, NetworkInterface},
+    network::{self, NetworkInterface, get_default_gateway},
     packet,
     scanners::{
         Device, IDLE_TIMEOUT, ScanMessage, Scanner, arp_scanner::ARPScanner,
@@ -179,6 +179,8 @@ fn print_arp(args: &Args, devices: &Vec<Device>) -> Result<()> {
         for d in devices.iter() {
             let ip_field = if d.is_current_host {
                 format!("{} [YOU]", d.ip)
+            } else if d.is_gateway {
+                format!("{} [GTWY]", d.ip)
             } else {
                 d.ip.to_string()
             };
@@ -265,6 +267,8 @@ fn print_syn(
         for d in devices {
             let ip_field = if d.is_current_host {
                 format!("{} [YOU]", d.ip)
+            } else if d.is_gateway {
+                format!("{} [GTWY]", d.ip)
             } else {
                 d.ip.to_string()
             };
@@ -321,12 +325,8 @@ fn main() -> Result<()> {
     }
 
     let interface = match &args.interface {
-        Some(name) => network::get_interface(name).ok_or_else(|| {
-            eyre!("Could not find network interface: {}", name)
-        })?,
-        None => network::get_default_interface().ok_or_else(|| {
-            eyre!("Could not detect default network interface")
-        })?,
+        Some(name) => network::get_interface(name)?,
+        None => network::get_default_interface()?,
     };
 
     args.interface = Some(interface.name.clone());
@@ -346,6 +346,7 @@ fn main() -> Result<()> {
     let arp = ARPScanner::builder()
         .interface(Arc::clone(&interface))
         .wire(wire.clone())
+        .gateway(get_default_gateway())
         .targets(
             IPTargets::new(args.targets.clone())
                 .map_err(|e| eyre!("Invalid IP targets: {}", e))?,

cli/src/main.rs

@@ -1,6 +1,5 @@
 use mockall::mock;
 use mpsc::channel;
-use pnet::util::MacAddr;
 use r_lanlib::{
     error::Result,
     scanners::{Port, PortSet, Scanner},
@@ -86,11 +85,8 @@ fn prints_arp_table_results() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
-        open_ports: PortSet::new(),
-        latency_ms: None,
+        ..Device::default()
     };
 
     print_arp(&args, &vec![device]).unwrap();
@@ -115,11 +111,8 @@ fn prints_arp_json_results() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
-        open_ports: PortSet::new(),
-        latency_ms: None,
+        ..Device::default()
     };
 
     print_arp(&args, &vec![device]).unwrap();
@@ -152,11 +145,9 @@ fn prints_syn_table_results() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
         open_ports,
-        latency_ms: None,
+        ..Device::default()
     };
 
     let devices = HashMap::from([(device.ip, device)]);
@@ -190,11 +181,9 @@ fn prints_syn_json_results() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
         open_ports,
-        latency_ms: None,
+        ..Device::default()
     };
 
     let devices = HashMap::from([(device.ip, device)]);
@@ -210,11 +199,8 @@ fn performs_arp_scan() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
-        open_ports: PortSet::new(),
-        latency_ms: None,
+        ..Device::default()
     };
 
     let device_clone = device.clone();
@@ -255,11 +241,9 @@ fn performs_syn_scan() {
     let device = Device {
         hostname: "hostname".to_string(),
         ip: Ipv4Addr::new(192, 168, 1, 1),
-        is_current_host: false,
-        mac: MacAddr::default(),
         vendor: "vendor".to_string(),
         open_ports: ports,
-        latency_ms: None,
+        ..Device::default()
     };
 
     let device_clone = device.clone();

cli/src/main_tests.rs

@@ -106,7 +106,9 @@ let devices = vec![
         mac: MacAddr::new(0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff),
         vendor: "".to_string(),
         is_current_host: false,
+        is_gateway: false,
         open_ports: PortSet::new(),
+        latency_ms: None,
     }
 ];
 
@@ -180,9 +182,18 @@ let handle = scanner.scan().expect("Failed to start scan");
 
 Provides helpers for selecting network interfaces:
 
-- `get_default_interface()` - Get the default network interface
-- `get_interface(name)` - Get a specific interface by name
-- `get_available_port()` - Find an available port for scanning
+- `get_default_interface()` - Get the default network interface, returns `Result<NetworkInterface>`
+- `get_interface(name)` - Get a specific interface by name, returns `Result<NetworkInterface>`
+- `get_available_port()` - Find an available port for scanning, returns `Result<u16>`
+
+#### `routing`
+
+Provides OS-level routing table inspection:
+
+- `get_default_gateway()` - Detect the default gateway IP address by parsing
+  the system routing table (`netstat -rn` on macOS, `ip route show` on Linux).
+  Returns `Option<Ipv4Addr>` — `None` if the gateway cannot be determined or
+  the platform is unsupported.
 
 #### `packet`
 
@@ -219,7 +230,9 @@ pub struct Device {
     pub mac: MacAddr,
     pub vendor: String,
     pub is_current_host: bool,
+    pub is_gateway: bool,
     pub open_ports: PortSet,
+    pub latency_ms: Option<u128>,
 }
 ```
 

lib/README.md

@@ -5,7 +5,8 @@ use std::{
 };
 
 use r_lanlib::{
-    network, packet,
+    network::{self, get_default_gateway},
+    packet,
     scanners::{Device, ScanMessage, Scanner, arp_scanner::ARPScanner},
     targets::ips::IPTargets,
 };
@@ -38,6 +39,7 @@ fn main() {
     let scanner = ARPScanner::builder()
         .interface(interface)
         .wire(wire)
+        .gateway(get_default_gateway())
         .targets(ip_targets)
         .source_port(source_port)
         .include_vendor(vendor)

lib/examples/arp-scanner.rs

@@ -36,6 +36,7 @@ fn main() {
             mac: MacAddr::new(0x00, 0x00, 0x00, 0x00, 0x00, 0x01),
             vendor: "".to_string(),
             is_current_host: false,
+            is_gateway: false,
             open_ports: PortSet::new(),
             latency_ms: None,
         },
@@ -45,6 +46,7 @@ fn main() {
             mac: MacAddr::new(0x00, 0x00, 0x00, 0x00, 0x00, 0x02),
             vendor: "".to_string(),
             is_current_host: false,
+            is_gateway: false,
             open_ports: PortSet::new(),
             latency_ms: None,
         },
@@ -54,6 +56,7 @@ fn main() {
             mac: MacAddr::new(0x00, 0x00, 0x00, 0x00, 0x00, 0x03),
             vendor: "".to_string(),
             is_current_host: false,
+            is_gateway: false,
             open_ports: PortSet::new(),
             latency_ms: None,
         },

lib/examples/syn-scanner.rs

@@ -77,6 +77,10 @@ pub enum RLanLibError {
     #[error("failed to build heartbeat packet: {_0}")]
     HeartbeatPacketBuild(#[from] HeartbeatPacketBuilderError),
 
+    /// Errors generated accessing device interfaces
+    #[error("network interface error: {_0}")]
+    NetworkInterface(String),
+
     /// Wrapping errors related to scanning
     #[error("scanning error: {error} - ip: {:#?}, port: {:#?}", ip, port)]
     Scan {