Add the up/down Device and Interface methods

Add up/down methods to Device and Interface for placing the underlying
device in a up or down state. This interface will also be handy when
adding support for MLDv2.

Author: dlrobertson

fuzz/fuzz_targets/tcp_headers.rs

@@ -20,7 +20,7 @@ mod utils {
 mod mock {
     use std::sync::Arc;
     use std::sync::atomic::{Ordering, AtomicUsize};
-	use smoltcp::time::{Duration, Instant};
+    use smoltcp::time::{Duration, Instant};
 
     // should be AtomicU64 but that's unstable
     #[derive(Debug, Clone)]
@@ -119,8 +119,8 @@ fuzz_target!(|data: &[u8]| {
         utils::add_middleware_options(&mut opts, &mut free);
 
         let mut matches = utils::parse_options(&opts, free);
-        let device = utils::parse_middleware_options(&mut matches, Loopback::new(Medium::Ethernet),
-                                                     /*loopback=*/true);
+        let loopback = Loopback::new(Medium::Ethernet);
+        let device = utils::parse_middleware_options(&mut matches, loopback, /*loopback=*/ true);
 
         smoltcp::phy::FuzzInjector::new(device,
                                         EmptyFuzzer(),
@@ -165,6 +165,9 @@ fuzz_target!(|data: &[u8]| {
     let mut did_listen  = false;
     let mut did_connect = false;
     let mut done = false;
+
+    iface.up().expect("Failed to set device up");
+
     while !done && clock.elapsed() < Instant::from_millis(4_000) {
         let _ = iface.poll(&mut socket_set, clock.elapsed());
 

fuzz/utils.rs

@@ -11,7 +11,7 @@ use std::env;
 use std::process;
 use getopts::{Options, Matches};
 
-use smoltcp::phy::{Device, EthernetTracer, FaultInjector};
+use smoltcp::phy::{Device, Tracer, FaultInjector};
 use smoltcp::phy::{PcapWriter, PcapSink, PcapMode, PcapLinkType};
 use smoltcp::time::Duration;
 
@@ -52,7 +52,7 @@ pub fn add_middleware_options(opts: &mut Options, _free: &mut Vec<&str>) {
 }
 
 pub fn parse_middleware_options<D>(matches: &mut Matches, device: D, loopback: bool)
-        -> FaultInjector<EthernetTracer<PcapWriter<D, Rc<PcapSink>>>>
+        -> FaultInjector<Tracer<PcapWriter<D, Rc<PcapSink>>>>
     where D: for<'a> Device<'a>
 {
     let drop_chance      = matches.opt_str("drop-chance").map(|s| u8::from_str(&s).unwrap())
@@ -78,9 +78,8 @@ pub fn parse_middleware_options<D>(matches: &mut Matches, device: D, loopback: b
     let seed = SystemTime::now().duration_since(UNIX_EPOCH).unwrap().subsec_nanos();
 
     let device = PcapWriter::new(device, Rc::new(RefCell::new(pcap_writer)) as Rc<PcapSink>,
-                                 if loopback { PcapMode::TxOnly } else { PcapMode::Both },
-                                 PcapLinkType::Ethernet);
-    let device = EthernetTracer::new(device, |_timestamp, _printer| {
+                                 if loopback { PcapMode::TxOnly } else { PcapMode::Both });
+    let device = Tracer::new(device, |_timestamp, _printer| {
         #[cfg(feature = "log")]
         trace!("{}", _printer);
     });

src/iface/interface.rs

@@ -568,6 +568,24 @@ where
         &mut self.inner.routes
     }
 
+    /// Trigger the startup sequence for the interface.
+    ///
+    /// This method will call [Device::up] on the backing device.
+    ///
+    /// [Device::up]: ../phy/trait.Device.html#method.up
+    pub fn up(&mut self) -> Result<()> {
+        self.device.up()
+    }
+
+    /// Trigger the shutdown sequence for the interface.
+    ///
+    /// This method will call [Device::down] on the backing device.
+    ///
+    /// [Device::down]: ../phy/trait.Device.html#method.down
+    pub fn down(&mut self) -> Result<()> {
+        self.device.down()
+    }
+
     /// Transmit packets queued in the given sockets, and receive packets queued
     /// in the device.
     ///
@@ -2107,7 +2125,9 @@ mod test {
         let iface_builder = InterfaceBuilder::new(device).ip_addrs(ip_addrs);
         #[cfg(feature = "proto-igmp")]
         let iface_builder = iface_builder.ipv4_multicast_groups(BTreeMap::new());
-        let iface = iface_builder.finalize();
+        let mut iface = iface_builder.finalize();
+
+        iface.up().expect("Failed to bring device up!");
 
         (iface, SocketSet::new(vec![]))
     }
@@ -2131,7 +2151,9 @@ mod test {
             .ip_addrs(ip_addrs);
         #[cfg(feature = "proto-igmp")]
         let iface_builder = iface_builder.ipv4_multicast_groups(BTreeMap::new());
-        let iface = iface_builder.finalize();
+        let mut iface = iface_builder.finalize();
+
+        iface.up().expect("Failed to bring device up!");
 
         (iface, SocketSet::new(vec![]))
     }
@@ -2169,6 +2191,34 @@ mod test {
         InterfaceBuilder::new(Loopback::new(Medium::Ethernet)).finalize();
     }
 
+    #[test]
+    #[cfg(feature = "medium-ethernet")]
+    fn test_iface_updown() {
+        let (mut iface, _) = create_loopback_ethernet();
+
+        iface.down().unwrap();
+
+        assert!(iface.device_mut().transmit().is_none());
+
+        iface.up().unwrap();
+
+        let tx_token = match iface.device_mut().transmit() {
+            Some(token) => token,
+            None => panic!("Failed to bring up device!"),
+        };
+
+        let buf = [0x00; 42];
+
+        tx_token.consume(Instant::from_millis(0), buf.len(), |tx_buf| {
+            tx_buf.copy_from_slice(&buf[..]);
+            Ok(())
+        }).unwrap();
+
+        iface.down().unwrap();
+
+        assert!(iface.device_mut().receive().is_none());
+    }
+
     #[test]
     #[cfg(feature = "proto-ipv4")]
     fn test_no_icmp_no_unicast_ipv4() {

src/phy/loopback.rs

@@ -11,7 +11,7 @@ use crate::Result;
 /// A loopback device.
 #[derive(Debug)]
 pub struct Loopback {
-    queue: VecDeque<Vec<u8>>,
+    queue: Option<VecDeque<Vec<u8>>>,
     medium: Medium,
 }
 
@@ -23,7 +23,7 @@ impl Loopback {
     /// in FIFO order.
     pub fn new(medium: Medium) -> Loopback {
         Loopback {
-            queue: VecDeque::new(),
+            queue: None,
             medium,
         }
     }
@@ -42,19 +42,35 @@ impl<'a> Device<'a> for Loopback {
     }
 
     fn receive(&'a mut self) -> Option<(Self::RxToken, Self::TxToken)> {
-        self.queue.pop_front().map(move |buffer| {
-            let rx = RxToken { buffer };
-            let tx = TxToken {
-                queue: &mut self.queue,
-            };
-            (rx, tx)
-        })
+        match self.queue {
+            Some(ref mut queue) => queue.pop_front().map(move |buffer| {
+                let rx = RxToken { buffer };
+                let tx = TxToken {
+                    queue: queue,
+                };
+                (rx, tx)
+            }),
+            None => None,
+        }
     }
 
     fn transmit(&'a mut self) -> Option<Self::TxToken> {
-        Some(TxToken {
-            queue: &mut self.queue,
-        })
+        match self.queue {
+            Some(ref mut queue) => Some(TxToken {
+                queue: queue,
+            }),
+            None => None,
+        }
+    }
+
+    fn up(&'a mut self) -> Result<()> {
+        self.queue = Some(VecDeque::new());
+        Ok(())
+    }
+
+    fn down(&'a mut self) -> Result<()> {
+        self.queue = None;
+        Ok(())
     }
 }
 

src/phy/mod.rs

@@ -310,6 +310,16 @@ pub trait Device<'a> {
 
     /// Get a description of device capabilities.
     fn capabilities(&self) -> DeviceCapabilities;
+
+    /// Place the device in a on or running state.
+    fn up(&'a mut self) -> Result<()> {
+        Ok(())
+    }
+
+    /// Place the device in a off or idle state.
+    fn down(&'a mut self) -> Result<()> {
+        Ok(())
+    }
 }
 
 /// A token to receive a single network packet.