stats: add statistics() to bridge, bond, and tun devices

Bridge: statistics() aggregates rx/tx bytes+packets from all member ports.
arp_stats() delegates to each port, showing per-port breakdown.

Bond: statistics() aggregates from all slaves (active+standby).
arp_stats() delegates to each slave.

TUN: statistics() now returns live counters tracked during send()/recv().
rx_bytes, rx_packets, tx_bytes, tx_packets increment per-packet.

Previously these devices returned Stats::default() (all zeros).
Now netcfg /ifaces/*/stats shows real data for bridge, bond, tun.

netstack/src/link/bond.rs

@@ -18,6 +18,7 @@ use smoltcp::time::Instant;
 use smoltcp::wire::{EthernetAddress, IpAddress, IpCidr};
 
 use super::LinkDevice;
+use super::Stats;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum BondMode {
@@ -166,4 +167,28 @@ impl LinkDevice for BondDevice {
         }
         out
     }
+
+    fn statistics(&self) -> Stats {
+        let mut total = Stats::default();
+        for s in self.slaves.borrow().iter() {
+            let stats = s.dev.statistics();
+            total.rx_bytes += stats.rx_bytes;
+            total.rx_packets += stats.rx_packets;
+            total.tx_bytes += stats.tx_bytes;
+            total.tx_packets += stats.tx_packets;
+        }
+        total
+    }
+
+    fn arp_stats(&self) -> String {
+        let mut out = String::new();
+        let slaves = self.slaves.borrow();
+        for (i, s) in slaves.iter().enumerate() {
+            let stats = s.dev.arp_stats();
+            if !stats.is_empty() {
+                out.push_str(&format!("slave{}: {}", i, stats));
+            }
+        }
+        out
+    }
 }

netstack/src/link/bridge.rs

@@ -23,6 +23,7 @@ use smoltcp::wire::{
 
 use super::stp::{self, BPDU_MAC, PortState, StpState};
 use super::LinkDevice;
+use super::Stats;
 
 const MAC_AGE_TIMEOUT: Duration = Duration::from_secs(300);
 
@@ -235,4 +236,27 @@ impl LinkDevice for BridgeDevice {
     fn link_state(&self) -> &'static str {
         if self.ports.borrow().is_empty() { "down" } else { "up" }
     }
+
+    fn statistics(&self) -> Stats {
+        let mut total = Stats::default();
+        for port in self.ports.borrow().iter() {
+            let s = port.statistics();
+            total.rx_bytes += s.rx_bytes;
+            total.rx_packets += s.rx_packets;
+            total.tx_bytes += s.tx_bytes;
+            total.tx_packets += s.tx_packets;
+        }
+        total
+    }
+
+    fn arp_stats(&self) -> String {
+        let mut out = String::new();
+        for (i, port) in self.ports.borrow().iter().enumerate() {
+            let s = port.arp_stats();
+            if !s.is_empty() {
+                out.push_str(&format!("port{}: {}", i, s));
+            }
+        }
+        out
+    }
 }

netstack/src/link/tun.rs

@@ -16,6 +16,7 @@ use smoltcp::time::Instant;
 use smoltcp::wire::{EthernetAddress, IpAddress, IpCidr};
 
 use super::LinkDevice;
+use super::Stats;
 
 pub type PacketQueue = Rc<RefCell<VecDeque<Vec<u8>>>>;
 
@@ -25,6 +26,7 @@ pub struct TunDevice {
     tx_queue: PacketQueue,
     recv_buffer: Vec<u8>,
     ip_address: Option<IpCidr>,
+    stats: Stats,
 }
 
 impl TunDevice {
@@ -35,17 +37,22 @@ impl TunDevice {
             tx_queue: tx,
             recv_buffer: Vec::new(),
             ip_address: None,
+            stats: Stats::default(),
         }
     }
 }
 
 impl LinkDevice for TunDevice {
     fn send(&mut self, _next_hop: IpAddress, packet: &[u8], _now: Instant) {
+        self.stats.tx_bytes += packet.len() as u64;
+        self.stats.tx_packets += 1;
         self.tx_queue.borrow_mut().push_back(packet.to_vec());
     }
 
     fn recv(&mut self, _now: Instant) -> Option<&[u8]> {
         self.recv_buffer = self.rx_queue.borrow_mut().pop_front()?;
+        self.stats.rx_bytes += self.recv_buffer.len() as u64;
+        self.stats.rx_packets += 1;
         Some(&self.recv_buffer)
     }
 
@@ -70,4 +77,8 @@ impl LinkDevice for TunDevice {
     fn set_ip_address(&mut self, addr: IpCidr) {
         self.ip_address = Some(addr);
     }
+
+    fn statistics(&self) -> Stats {
+        self.stats
+    }
 }