add support for moving devices into the namespace

Cargo.lock

@@ -507,7 +507,7 @@ dependencies = [
 
 [[package]]
 name = "netnsd"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "clap",
  "either",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "netnsd"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2024"
 rust-version = "1.88.0"
 

README.md

@@ -6,7 +6,8 @@ A declarative manager for Linux network namespaces.
 
 - Fully declarative configuration
 - Hot reloading of configuration
-- Port forwarding into the namespace
+- Port forwarding into or out of the namespace
+- Moving network devices to the namespace
 
 ## Usage
 
@@ -53,6 +54,8 @@ You can specify a different configuration path with the `--config` option.
 [[namespace]]
 # name of the namespace to create
 name = "test"
+# move existing devices into the namespace
+devices = ["somelink"]
 
 # You can define any number of port forwards to setup into the namespace
 [[namespace.forward]]

config.sample.toml

@@ -2,6 +2,8 @@
 [[namespace]]
 # name of the namespace to create
 name = "test"
+# move existing devices into the namespace
+devices = ["somelink"]
 
 # You can define any number of port forwards to setup into the namespace
 [[namespace.forward]]

src/config/mod.rs

@@ -2,7 +2,7 @@ mod name;
 mod source;
 mod target;
 
-pub use crate::config::name::NamespaceName;
+pub use crate::config::name::{DeviceName, NamespaceName};
 pub use crate::config::source::ForwardSource;
 pub use crate::config::target::ForwardTarget;
 use serde::Deserialize;
@@ -80,7 +80,10 @@ impl RawConfig {
 #[derive(Deserialize, Debug)]
 pub struct NamespaceConfig {
     pub name: NamespaceName,
+    #[serde(default)]
     pub forward: Vec<ForwardConfig>,
+    #[serde(default)]
+    pub devices: Vec<DeviceName>,
 }
 
 #[derive(Deserialize, Debug)]

src/config/name.rs

@@ -7,8 +7,18 @@ use std::str::FromStr;
 use thiserror::Error;
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
+struct ValidatedName(String);
+
+#[derive(Debug, Clone, Eq, PartialEq, Hash, Deserialize)]
+#[serde(from = "ValidatedName")]
 pub struct NamespaceName(String);
 
+impl From<ValidatedName> for NamespaceName {
+    fn from(value: ValidatedName) -> Self {
+        NamespaceName(value.0)
+    }
+}
+
 impl TryFrom<OsString> for NamespaceName {
     type Error = ();
 
@@ -52,7 +62,60 @@ impl From<NamespaceName> for String {
     }
 }
 
-impl<'de> Deserialize<'de> for NamespaceName {
+#[derive(Debug, Clone, Eq, PartialEq, Hash, Deserialize)]
+#[serde(from = "ValidatedName")]
+pub struct DeviceName(String);
+
+impl From<ValidatedName> for DeviceName {
+    fn from(value: ValidatedName) -> Self {
+        DeviceName(value.0)
+    }
+}
+
+impl TryFrom<OsString> for DeviceName {
+    type Error = ();
+
+    fn try_from(value: OsString) -> Result<Self, Self::Error> {
+        let str = value.into_string().map_err(|_| ())?;
+        if validate_name(&str) {
+            Ok(DeviceName(str))
+        } else {
+            Err(())
+        }
+    }
+}
+
+impl Display for DeviceName {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl AsRef<str> for DeviceName {
+    fn as_ref(&self) -> &str {
+        self.0.as_ref()
+    }
+}
+
+impl AsRef<Path> for DeviceName {
+    fn as_ref(&self) -> &Path {
+        self.0.as_ref()
+    }
+}
+
+impl PartialEq<&str> for DeviceName {
+    fn eq(&self, other: &&str) -> bool {
+        self.0 == *other
+    }
+}
+
+impl From<DeviceName> for String {
+    fn from(value: DeviceName) -> Self {
+        value.0
+    }
+}
+
+impl<'de> Deserialize<'de> for ValidatedName {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
         D: Deserializer<'de>,
@@ -60,7 +123,7 @@ impl<'de> Deserialize<'de> for NamespaceName {
         struct NamespaceNameVisitor;
 
         impl Visitor<'_> for NamespaceNameVisitor {
-            type Value = NamespaceName;
+            type Value = ValidatedName;
 
             fn expecting(&self, formatter: &mut Formatter) -> std::fmt::Result {
                 formatter.write_str("A valid namespace name")
@@ -73,7 +136,7 @@ impl<'de> Deserialize<'de> for NamespaceName {
                 if !validate_name(v) {
                     return Err(E::invalid_value(Unexpected::Str(v), &self));
                 }
-                Ok(NamespaceName(v.into()))
+                Ok(ValidatedName(v.into()))
             }
 
             fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
@@ -83,7 +146,7 @@ impl<'de> Deserialize<'de> for NamespaceName {
                 if !validate_name(&v) {
                     return Err(E::invalid_value(Unexpected::Str(&v), &self));
                 }
-                Ok(NamespaceName(v))
+                Ok(ValidatedName(v))
             }
         }
 
@@ -92,20 +155,24 @@ impl<'de> Deserialize<'de> for NamespaceName {
 }
 
 impl FromStr for NamespaceName {
-    type Err = InvalidNamespaceNameError;
+    type Err = InvalidNameError;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         if !validate_name(s) {
-            return Err(InvalidNamespaceNameError { name: s.into() });
+            return Err(InvalidNameError {
+                name: s.into(),
+                kind: "namespace",
+            });
         }
         Ok(NamespaceName(s.into()))
     }
 }
 
 #[derive(Debug, Error)]
-#[error("invalid name for namespace: '{name}'")]
-pub struct InvalidNamespaceNameError {
+#[error("invalid name for {kind}: '{name}'")]
+pub struct InvalidNameError {
     name: String,
+    kind: &'static str,
 }
 
 /// Check if a name follows the portable filename character set

src/daemon.rs

@@ -1,5 +1,8 @@
-use crate::config::{Config, ForwardConfig, NamespaceConfig, NamespaceName};
-use crate::namespace::{NamespaceError, NetNs};
+use crate::config::{Config, DeviceName, ForwardConfig, NamespaceConfig, NamespaceName};
+use crate::link::{LinkError, LinkManager};
+use crate::namespace::{
+    NamespaceEnterError, NamespaceError, NamespaceHandle, NamespaceHandleError, NetNs,
+};
 use crate::proxy::{ActiveProxy, ProxyError};
 use futures::FutureExt;
 use futures::StreamExt;
@@ -124,6 +127,7 @@ impl State {
         for namespace in &mut self.namespaces {
             let config = config.get_namespace(namespace.name()).unwrap();
             namespace.update_proxies(config)?;
+            namespace.update_devices(config)?;
         }
 
         Ok(())
@@ -139,6 +143,7 @@ impl State {
 struct ActiveNamespace {
     ns: NetNs,
     proxies: Vec<ActiveProxy>,
+    devices: Vec<DeviceName>,
 }
 
 impl ActiveNamespace {
@@ -148,6 +153,7 @@ impl ActiveNamespace {
         Ok(ActiveNamespace {
             ns,
             proxies: Vec::default(),
+            devices: Vec::default(),
         })
     }
 
@@ -164,10 +170,56 @@ impl ActiveNamespace {
         Ok(())
     }
 
+    pub fn update_devices(&mut self, config: &NamespaceConfig) -> Result<(), DaemonError> {
+        let parent_namespace = NamespaceHandle::parent()?;
+
+        let removed: Vec<_> = self
+            .devices
+            .extract_if(.., |existing| {
+                !config.devices.iter().any(|new| existing == new)
+            })
+            .collect();
+
+        self.ns.handle().run_in(move || {
+            let link_manager = LinkManager::new()?;
+            for link in link_manager.get_links()?.flatten() {
+                if removed.iter().any(|name| *name == link.name.as_str()) {
+                    info!(namespace = %config.name, link = link.name , "moving link out of namespace");
+                    link_manager.move_link(&link, &parent_namespace)?
+                }
+            }
+            Ok::<_, LinkError>(())
+        })??;
+
+        let mut added = Vec::new();
+        for new in &config.devices {
+            if !self.has_device(new) {
+                added.push(new.clone());
+            }
+        }
+
+        let link_manager = LinkManager::new()?;
+        for link in link_manager.get_links()?.flatten() {
+            if added.iter().any(|name| *name == link.name.as_str()) {
+                info!(namespace = %config.name, link = link.name , "moving link into namespace");
+                link_manager.move_link(&link, self.ns.handle())?
+            }
+        }
+        for new in added {
+            self.devices.push(new);
+        }
+
+        Ok(())
+    }
+
     fn has_forward(&self, config: &ForwardConfig) -> bool {
         self.proxies.iter().any(|existing| existing == config)
     }
 
+    fn has_device(&self, name: &DeviceName) -> bool {
+        self.devices.iter().any(|existing| existing == name)
+    }
+
     pub fn name(&self) -> &NamespaceName {
         self.ns.name()
     }
@@ -183,4 +235,10 @@ pub enum DaemonError {
     Signal(IoError),
     #[error(transparent)]
     Proxy(#[from] ProxyError),
+    #[error(transparent)]
+    Handle(#[from] NamespaceHandleError),
+    #[error(transparent)]
+    Enter(#[from] NamespaceEnterError),
+    #[error(transparent)]
+    Link(#[from] LinkError),
 }

src/link.rs

@@ -1,3 +1,4 @@
+use crate::namespace::{NamespaceEnterError, NamespaceHandle};
 use neli::consts::nl::NlmF;
 use neli::consts::rtnl::Ifla;
 use neli::consts::rtnl::RtAddrFamily;
@@ -6,16 +7,14 @@ use neli::consts::socket::NlFamily;
 use neli::err::RouterError;
 use neli::nl::NlPayload;
 use neli::router::synchronous::NlRouter;
-use neli::rtnl::Ifinfomsg;
 use neli::rtnl::IfinfomsgBuilder;
+use neli::rtnl::{Ifinfomsg, RtattrBuilder};
+use neli::types::{Buffer, RtBuffer};
 use neli::utils::Groups;
-use nix::errno::Errno;
-use nix::sched::{setns, CloneFlags};
-use std::fs::File;
-use std::io::Error as IoError;
-use std::path::{Path, PathBuf};
-use std::thread::spawn;
+use nix::libc::c_int;
+use std::os::fd::AsRawFd;
 use thiserror::Error;
+use tracing::info;
 
 #[derive(Debug, Error)]
 pub enum LinkError {
@@ -23,12 +22,10 @@ pub enum LinkError {
     Netlink,
     #[error("failed to code netlink response")]
     Parse,
-    #[error("unexpected panic in link setup")]
-    Panic,
-    #[error("failed to enter namespace in link setup: {0}")]
-    Namespace(Errno),
-    #[error("Failed to open namespace file {}: {error:#}", path.display())]
-    OpenNamespace { path: PathBuf, error: IoError },
+    #[error("Link not found: {0}")]
+    NotFound(String),
+    #[error(transparent)]
+    Enter(#[from] NamespaceEnterError),
 }
 
 impl<T, P> From<RouterError<T, P>> for LinkError {
@@ -37,60 +34,133 @@ impl<T, P> From<RouterError<T, P>> for LinkError {
     }
 }
 
-/// Set a link to UP inside a namespace
-pub fn link_up_ns(namespace: impl AsRef<Path>, link_name: &'static str) -> Result<(), LinkError> {
-    let namespace = namespace.as_ref();
-    let ns_handle = File::open(namespace).map_err(|error| LinkError::OpenNamespace {
-        error,
-        path: namespace.into(),
-    })?;
+pub struct LinkManager {
+    router: NlRouter,
+}
 
-    spawn(move || {
-        setns(ns_handle, CloneFlags::CLONE_NEWNET).map_err(LinkError::Namespace)?;
-        link_up(link_name)
-    })
-    .join()
-    .map_err(|_| LinkError::Panic)?
+pub struct Link {
+    family: RtAddrFamily,
+    index: c_int,
+    pub name: String,
+}
+
+impl Link {
+    fn msg_builder(&self) -> IfinfomsgBuilder {
+        IfinfomsgBuilder::default()
+            .ifi_family(self.family)
+            .ifi_index(self.index)
+    }
+}
+
+impl LinkManager {
+    pub fn new() -> Result<Self, LinkError> {
+        let (router, _) = NlRouter::connect(NlFamily::Route, None, Groups::empty())?;
+        router.enable_ext_ack(true)?;
+        router.enable_strict_checking(true)?;
+        Ok(LinkManager { router })
+    }
+
+    pub fn get_link(&self, name: impl AsRef<str>) -> Result<Link, LinkError> {
+        let name = name.as_ref();
+        for link in self.get_links()? {
+            let link = link?;
+            if link.name == name {
+                return Ok(link);
+            }
+        }
+        Err(LinkError::NotFound(name.into()))
+    }
+
+    pub fn get_links(&self) -> Result<impl Iterator<Item = Result<Link, LinkError>>, LinkError> {
+        let ifinfomsg = IfinfomsgBuilder::default()
+            .ifi_family(RtAddrFamily::Inet)
+            .build()
+            .unwrap();
+
+        let recv = self.router.send::<_, _, Rtm, Ifinfomsg>(
+            Rtm::Getlink,
+            NlmF::DUMP | NlmF::ACK,
+            NlPayload::Payload(ifinfomsg),
+        )?;
+        Ok(recv
+            .map(|response| {
+                if let Some(payload) = response?.get_payload() {
+                    let name = payload
+                        .rtattrs()
+                        .get_attr_handle()
+                        .get_attr_payload_as_with_len::<String>(Ifla::Ifname)
+                        .map_err(|_| LinkError::Parse)?;
+                    Ok(Some(Link {
+                        family: *payload.ifi_family(),
+                        index: *payload.ifi_index(),
+                        name,
+                    }))
+                } else {
+                    Ok(None)
+                }
+            })
+            .filter_map(|item| item.transpose()))
+    }
+
+    /// Move a link to a namespace
+    pub fn move_link<Fd: AsRawFd>(&self, link: &Link, namespace: Fd) -> Result<(), LinkError> {
+        let ns_handle = namespace.as_raw_fd();
+
+        let mut info_attrs = RtBuffer::<Ifla, Buffer>::new();
+        info_attrs.push(
+            RtattrBuilder::default()
+                .rta_type(Ifla::NetNsFd)
+                .rta_payload(Buffer::from(ns_handle.to_ne_bytes().as_slice()))
+                .build()
+                .expect("invalid rtattr"),
+        );
+
+        let msg = link.msg_builder().rtattrs(info_attrs).build().unwrap();
+        self.router.send::<_, _, Rtm, Ifinfomsg>(
+            Rtm::Setlink,
+            NlmF::ACK,
+            NlPayload::Payload(msg),
+        )?;
+        Ok(())
+    }
 }
 
 /// Set a link to UP
 pub fn link_up(link_name: &str) -> Result<(), LinkError> {
-    // I honestly don't really know how this code works
-    // It's mostly a copy from one of neli's examples and seems to do what it needs to
-    let (rtnl, _) = NlRouter::connect(NlFamily::Route, None, Groups::empty())?;
-    rtnl.enable_ext_ack(true)?;
-    rtnl.enable_strict_checking(true)?;
-    let ifinfomsg = IfinfomsgBuilder::default()
-        .ifi_family(RtAddrFamily::Inet)
-        .build()
-        .unwrap();
+    let manager = LinkManager::new()?;
+    let link = manager.get_link(link_name)?;
 
-    let recv = rtnl.send::<_, _, Rtm, Ifinfomsg>(
-        Rtm::Getlink,
-        NlmF::DUMP | NlmF::ACK,
-        NlPayload::Payload(ifinfomsg),
+    let up_msg = link.msg_builder().up().build().unwrap();
+    manager.router.send::<_, _, Rtm, Ifinfomsg>(
+        Rtm::Setlink,
+        NlmF::ACK,
+        NlPayload::Payload(up_msg),
     )?;
-    for response in recv {
-        if let Some(payload) = response?.get_payload() {
-            let name = payload
-                .rtattrs()
-                .get_attr_handle()
-                .get_attr_payload_as_with_len::<String>(Ifla::Ifname)
-                .map_err(|_| LinkError::Parse)?;
-            if name == link_name {
-                let up_msg = IfinfomsgBuilder::default()
-                    .ifi_family(RtAddrFamily::Inet)
-                    .ifi_index(*payload.ifi_index())
-                    .up()
-                    .build()
-                    .unwrap();
-                rtnl.send::<_, _, Rtm, Ifinfomsg>(
-                    Rtm::Setlink,
-                    NlmF::ACK,
-                    NlPayload::Payload(up_msg),
-                )?;
+    Ok(())
+}
+
+/// Move a link into a namespace
+pub fn move_link_into(link_name: &str, namespace: &NamespaceHandle) -> Result<(), LinkError> {
+    let manager = LinkManager::new()?;
+    let link = manager.get_link(link_name)?;
+    info!(name = &link.name, "moving link into namespace");
+    manager.move_link(&link, namespace)
+}
+
+/// Move all  links out of a namespace, except for lo
+pub fn move_all_links_out(
+    namespace: &NamespaceHandle,
+    parent: &NamespaceHandle,
+) -> Result<(), LinkError> {
+    namespace.run_in(|| {
+        let manager = LinkManager::new()?;
+        for link in manager.get_links()?.flatten() {
+            if link.name != "lo" {
+                info!(name = &link.name, "moving link out of namespace");
+                manager.move_link(&link, parent)?
             }
         }
-    }
+        Ok::<_, LinkError>(())
+    })??;
     Ok(())
 }

src/namespace/handle.rs

@@ -0,0 +1,76 @@
+use crate::namespace::NamespaceEnterError;
+use nix::errno::Errno;
+use nix::sched::{setns, CloneFlags};
+use std::fs::File;
+use std::io::Error as IoError;
+use std::os::fd::{AsFd, AsRawFd, BorrowedFd, OwnedFd, RawFd};
+use std::path::{Path, PathBuf};
+use std::thread::scope;
+use thiserror::Error;
+
+pub struct NamespaceHandle {
+    path: PathBuf,
+    fd: OwnedFd,
+}
+
+impl NamespaceHandle {
+    /// Open the namespace handle for a path
+    pub fn open<P: AsRef<Path>>(path: P) -> Result<Self, NamespaceHandleError> {
+        let path = path.as_ref();
+        let file = File::open(path).map_err(|error| NamespaceHandleError::Open {
+            error,
+            path: path.into(),
+        })?;
+        Ok(NamespaceHandle {
+            path: path.into(),
+            fd: file.into(),
+        })
+    }
+
+    /// Open the namespace handle for the namespace the current process is in
+    pub fn parent() -> Result<Self, NamespaceHandleError> {
+        Self::open("/proc/self/ns/net")
+    }
+
+    pub fn run_in<T: Send, F: FnOnce() -> T + Send>(&self, f: F) -> Result<T, NamespaceEnterError> {
+        scope(|scope| {
+            scope
+                .spawn(|| {
+                    setns(&self.fd, CloneFlags::CLONE_NEWNET)?;
+                    Ok(f())
+                })
+                .join()
+                .expect("namespace thread panicked")
+        })
+        .map_err(|error| NamespaceEnterError {
+            namespace: self.path.clone(),
+            error,
+        })
+    }
+}
+
+impl AsFd for NamespaceHandle {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.fd.as_fd()
+    }
+}
+
+impl AsRawFd for NamespaceHandle {
+    fn as_raw_fd(&self) -> RawFd {
+        self.fd.as_raw_fd()
+    }
+}
+
+impl AsRawFd for &NamespaceHandle {
+    fn as_raw_fd(&self) -> RawFd {
+        self.fd.as_raw_fd()
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum NamespaceHandleError {
+    #[error("Failed to open namespace handle {}: {error:#}", path.display())]
+    Open { path: PathBuf, error: IoError },
+    #[error("Failed to enter namespace: {0:#}")]
+    Enter(Errno),
+}

src/namespace/mod.rs

@@ -1,27 +1,32 @@
+mod handle;
 mod raw;
 
-use crate::config::NamespaceName;
-use crate::link::{LinkError, link_up_ns};
-use crate::namespace::raw::{NamespaceSetupError, create_network_namespace};
+use crate::config::{DeviceName, NamespaceName};
+use crate::link::{link_up, move_all_links_out, move_link_into, LinkError};
+pub use crate::namespace::handle::{NamespaceHandle, NamespaceHandleError};
+use crate::namespace::raw::{create_network_namespace, NamespaceSetupError};
 use either::Either;
 use nix::errno::Errno;
-use nix::mount::{MntFlags, MsFlags, mount, umount2};
-use std::fs::{File, create_dir, read_dir, remove_file};
+use nix::mount::{mount, umount2, MntFlags, MsFlags};
+use std::fs::{create_dir, read_dir, remove_file, File};
 use std::io::{Error as IoError, ErrorKind};
 use std::iter::empty;
 use std::os::unix::fs::symlink;
 use std::path::{Path, PathBuf};
 use thiserror::Error;
-use tracing::{debug, error, info};
+use tracing::{debug, info};
 
 pub struct NetNs {
     name: NamespaceName,
     path: PathBuf,
     nsd_path: PathBuf,
+    handle: NamespaceHandle,
 }
 
 impl NetNs {
-    pub fn existing(include_broken: bool) -> Result<impl Iterator<Item = NamespaceName>, NamespaceError> {
+    pub fn existing(
+        include_broken: bool,
+    ) -> Result<impl Iterator<Item = NamespaceName>, NamespaceError> {
         let dir = match read_dir("/var/run/netnsd") {
             Ok(dir) => Ok(dir),
             Err(error) if error.kind() == ErrorKind::NotFound => {
@@ -71,10 +76,12 @@ impl NetNs {
                     })?;
                 }
 
+                let handle = NamespaceHandle::open(&path)?;
                 return Ok(NetNs {
                     name,
                     nsd_path,
                     path,
+                    handle,
                 });
             }
             Err(e) => return Err(NamespaceError::from_create(path.clone(), e)),
@@ -89,10 +96,12 @@ impl NetNs {
                     path: nsd_path.clone(),
                 })?;
             }
+            let handle = NamespaceHandle::open(&path)?;
             Result::<_, NamespaceError>::Ok(NetNs {
                 name,
                 path,
                 nsd_path,
+                handle,
             })
         })?;
 
@@ -145,11 +154,15 @@ impl NetNs {
     }
 
     fn setup_interfaces(&self) -> Result<(), NamespaceError> {
-        link_up_ns(&self.path, "lo")?;
+        self.handle
+            .run_in(move || link_up("lo").map_err(NamespaceError::from))??;
         Ok(())
     }
 
     pub fn delete(self) -> Result<(), NamespaceError> {
+        let parent_namespace = NamespaceHandle::parent()?;
+
+        move_all_links_out(self.handle(), &parent_namespace)?;
         let name = self.path.file_name().unwrap().to_str().unwrap();
         info!(name, "deleting network namespace");
         match umount2(&self.path, MntFlags::MNT_DETACH) {
@@ -167,6 +180,16 @@ impl NetNs {
         })?;
         Ok(())
     }
+
+    /// Move a device into this namespace
+    pub fn move_device(&self, device: &DeviceName) -> Result<(), LinkError> {
+        move_link_into(device.as_ref(), self.handle())
+    }
+
+    /// Get the namespace handle
+    pub fn handle(&self) -> &NamespaceHandle {
+        &self.handle
+    }
 }
 
 #[derive(Debug, Error)]
@@ -187,10 +210,14 @@ pub enum NamespaceError {
     Mount(Errno),
     #[error("Failed to unmount netns handle: {0:?}")]
     UnMount(Errno),
-    #[error("Failed to setup loopback inside namespace: {0:#}")]
-    Link(#[from] LinkError),
     #[error("Failed to scan {} for namespaces: {error:#}", path.display())]
     Scan { path: PathBuf, error: IoError },
+    #[error(transparent)]
+    Handle(#[from] NamespaceHandleError),
+    #[error(transparent)]
+    Enter(#[from] NamespaceEnterError),
+    #[error(transparent)]
+    Link(#[from] LinkError),
 }
 
 impl NamespaceError {
@@ -199,6 +226,13 @@ impl NamespaceError {
     }
 }
 
+#[derive(Debug, Error)]
+#[error("Error while entering namespace {}: {0:#}", namespace.display())]
+pub struct NamespaceEnterError {
+    namespace: PathBuf,
+    error: Errno,
+}
+
 /// `remove_file`, but ignore "file not found" errors
 fn remove_file_if_exists<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
     match remove_file(path) {
@@ -207,7 +241,6 @@ fn remove_file_if_exists<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
     }
 }
 
-
 /// `remove_file`, but ignore errors if the file doesn't exist or is a mount point
 fn remove_non_mount<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
     match remove_file(path) {
@@ -215,4 +248,4 @@ fn remove_non_mount<P: AsRef<Path>>(path: P) -> std::io::Result<()> {
         Err(err) if err.kind() == ErrorKind::ResourceBusy => Ok(()),
         rest => rest,
     }
-}
+}

src/up.rs

@@ -1,6 +1,7 @@
 use crate::config::{Config, NamespaceName};
 use crate::namespace::NetNs;
 use main_error::MainResult;
+use tracing::error;
 
 pub fn up(config: Config) -> MainResult {
     let mut namespaces = NetNs::existing(false)?
@@ -15,7 +16,13 @@ pub fn up(config: Config) -> MainResult {
 
     for new in config.namespaces {
         if !has_namespace(&namespaces, &new.name) {
-            namespaces.push(NetNs::new(new.name)?);
+            namespaces.push(NetNs::new(new.name.clone())?);
+        }
+        let namespace = get_namespace(&namespaces, &new.name).expect("namespace is just created");
+        for device in new.devices {
+            if let Err(error) = namespace.move_device(&device) {
+                error!(%error, "failed to move device into namespace");
+            }
         }
     }
 
@@ -25,3 +32,7 @@ pub fn up(config: Config) -> MainResult {
 fn has_namespace(namespaces: &[NetNs], name: &NamespaceName) -> bool {
     namespaces.iter().any(|existing| existing.name() == name)
 }
+
+fn get_namespace<'a>(namespaces: &'a [NetNs], name: &NamespaceName) -> Option<&'a NetNs> {
+    namespaces.iter().find(|existing| existing.name() == name)
+}