move proxies to sub-processes

Cargo.lock

@@ -433,15 +433,6 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
-[[package]]
-name = "humansize"
-version = "2.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6cb51c9a029ddc91b07a787f1d86b53ccfa49b0e86688c946ebe8d3555685dd7"
-dependencies = [
- "libm",
-]
-
 [[package]]
 name = "ident_case"
 version = "1.0.1"
@@ -476,12 +467,6 @@ version = "0.2.177"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
 
-[[package]]
-name = "libm"
-version = "0.2.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9fbbcab51052fe104eb5e5d351cf728d30a5be1fe14d9be8a3b097481fb97de"
-
 [[package]]
 name = "lock_api"
 version = "0.4.14"
@@ -579,14 +564,12 @@ dependencies = [
  "either",
  "futures",
  "futures-concurrency",
- "humansize",
  "main_error",
  "neli",
  "nix",
  "sd-notify",
  "serde",
  "serde_test",
- "syscalls",
  "thiserror",
  "tokio",
  "tokio-stream",
@@ -813,17 +796,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "serde_repr"
-version = "0.1.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "175ee3e80ae9982737ca543e96133087cbd9a485eecc3bc4de9c1a37b47ea59c"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "serde_spanned"
 version = "1.0.3"
@@ -911,16 +883,6 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "syscalls"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90db46b5b4962319605d435986c775ea45a0ad2561c09e1d5372b89afeb49cf4"
-dependencies = [
- "serde",
- "serde_repr",
-]
-
 [[package]]
 name = "thiserror"
 version = "2.0.17"

Cargo.toml

@@ -14,15 +14,13 @@ thiserror = "2.0.17"
 tracing = "0.1.41"
 tracing-subscriber = "0.3.20"
 main_error = "0.1.2"
-nix = { version = "0.30.1", features = ["mount", "sched"] }
+nix = { version = "0.30.1", features = ["mount", "sched", "user", "signal"] }
 sd-notify = "0.4.5"
 futures = "0.3.31"
 futures-concurrency = "7.6.3"
-humansize = { version = "2.1.3", features = ["no_alloc"] }
 neli = "0.7.1"
 either = "1.15.0"
 uzers = "0.12.1"
-syscalls = "0.7.0"
 
 [dev-dependencies]
 serde_test = "1.0.177"

src/config/name.rs

@@ -3,6 +3,8 @@ use serde::{Deserialize, Deserializer};
 use std::ffi::OsString;
 use std::fmt::{Display, Formatter};
 use std::path::Path;
+use std::str::FromStr;
+use thiserror::Error;
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct NamespaceName(String);
@@ -38,6 +40,12 @@ impl AsRef<Path> for NamespaceName {
     }
 }
 
+impl PartialEq<&str> for NamespaceName {
+    fn eq(&self, other: &&str) -> bool {
+        self.0 == *other
+    }
+}
+
 impl From<NamespaceName> for String {
     fn from(value: NamespaceName) -> Self {
         value.0
@@ -83,6 +91,23 @@ impl<'de> Deserialize<'de> for NamespaceName {
     }
 }
 
+impl FromStr for NamespaceName {
+    type Err = InvalidNamespaceNameError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if !validate_name(s) {
+            return Err(InvalidNamespaceNameError { name: s.into() });
+        }
+        Ok(NamespaceName(s.into()))
+    }
+}
+
+#[derive(Debug, Error)]
+#[error("invalid name for namespace: '{name}'")]
+pub struct InvalidNamespaceNameError {
+    name: String,
+}
+
 /// Check if a name follows the portable filename character set
 fn validate_name(name: &str) -> bool {
     if name.is_empty() {

src/config/source.rs

@@ -4,6 +4,7 @@ use std::fmt::{Display, Formatter};
 use std::net::{IpAddr, SocketAddr};
 use std::path::PathBuf;
 use std::str::FromStr;
+use thiserror::Error;
 
 #[derive(Debug, PartialEq, Clone, Hash, Eq)]
 pub enum ForwardSource {
@@ -77,17 +78,8 @@ impl<'de> Deserialize<'de> for ForwardSource {
             where
                 E: Error,
             {
-                if v.starts_with('/') {
+                v.parse()
-                    Ok(ForwardSource::Unix(v.into()))
+                    .map_err(|_| E::invalid_value(Unexpected::Str(v), &self))
-                } else {
-                    if let Ok(port) = u16::from_str(v) {
-                        return self.visit_u16(port);
-                    }
-                    let addr = v
-                        .parse()
-                        .map_err(|_| E::invalid_value(Unexpected::Str(v), &self))?;
-                    Ok(ForwardSource::Ip(addr))
-                }
             }
         }
 
@@ -95,6 +87,31 @@ impl<'de> Deserialize<'de> for ForwardSource {
     }
 }
 
+impl FromStr for ForwardSource {
+    type Err = InvalidForwardSource;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.starts_with('/') {
+            Ok(ForwardSource::Unix(s.into()))
+        } else {
+            if let Ok(port) = u16::from_str(s) {
+                let ip = IpAddr::from([0, 0, 0, 0]);
+                return Ok(ForwardSource::Ip(SocketAddr::from((ip, port))));
+            }
+            let addr = s
+                .parse()
+                .map_err(|_| InvalidForwardSource { forward: s.into() })?;
+            Ok(ForwardSource::Ip(addr))
+        }
+    }
+}
+
+#[derive(Debug, Error)]
+#[error("forward source '{forward}' is not a valid unix path or socket address")]
+pub struct InvalidForwardSource {
+    forward: String,
+}
+
 #[test]
 fn test_de() {
     use serde_test::{assert_de_tokens, assert_de_tokens_error, Token};

src/config/target.rs

@@ -3,6 +3,7 @@ use serde::{Deserialize, Deserializer};
 use std::fmt::{Display, Formatter};
 use std::net::{IpAddr, SocketAddr};
 use std::str::FromStr;
+use thiserror::Error;
 
 #[derive(Debug, PartialEq, Clone, Hash, Eq)]
 pub struct ForwardTarget {
@@ -70,13 +71,8 @@ impl<'de> Deserialize<'de> for ForwardTarget {
             where
                 E: Error,
             {
-                if let Ok(port) = u16::from_str(v) {
+                v.parse()
-                    return self.visit_u16(port);
+                    .map_err(|_| E::invalid_value(Unexpected::Str(v), &self))
-                }
-                let addr = v
-                    .parse()
-                    .map_err(|_| E::invalid_value(Unexpected::Str(v), &self))?;
-                Ok(ForwardTarget { addr })
             }
         }
 
@@ -84,6 +80,29 @@ impl<'de> Deserialize<'de> for ForwardTarget {
     }
 }
 
+impl FromStr for ForwardTarget {
+    type Err = InvalidForwardTarget;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if let Ok(port) = u16::from_str(s) {
+            let ip = IpAddr::from([127, 0, 0, 1]);
+            return Ok(ForwardTarget {
+                addr: SocketAddr::from((ip, port)),
+            });
+        }
+        let addr = s
+            .parse()
+            .map_err(|_| InvalidForwardTarget { forward: s.into() })?;
+        Ok(ForwardTarget { addr })
+    }
+}
+
+#[derive(Debug, Error)]
+#[error("forward source '{forward}' is not a valid socket address")]
+pub struct InvalidForwardTarget {
+    forward: String,
+}
+
 #[test]
 fn test_de() {
     use serde_test::{assert_de_tokens, assert_de_tokens_error, Token};

src/daemon.rs

@@ -4,7 +4,6 @@ use crate::proxy::{ActiveProxy, ProxyError};
 use futures::FutureExt;
 use futures::StreamExt;
 use futures_concurrency::stream::Merge;
-use humansize::{BINARY, SizeFormatter};
 use main_error::MainResult;
 use sd_notify::{NotifyState, notify};
 use std::io::Error as IoError;
@@ -78,13 +77,9 @@ async fn daemon_async(mut config: Config) -> Result<(), DaemonError> {
                     println!("{}:", namespace.name());
                     for proxy in &namespace.proxies {
                         println!(
-                            "  {} => {} {} connections ({} active), {} sent to namespace, {} received from namespace",
+                            "  {} => {}",
                             proxy.source,
                             proxy.destination,
-                            proxy.stats.total_connections(),
-                            proxy.stats.open_connections(),
-                            SizeFormatter::new(proxy.stats.written(), BINARY),
-                            SizeFormatter::new(proxy.stats.read(), BINARY),
                         );
                     }
                 }

src/main.rs

@@ -1,9 +1,10 @@
 use std::path::{PathBuf};
 use clap::{Parser, Subcommand};
 use main_error::MainResult;
-use crate::config::Config;
+use crate::config::{Config, ForwardSource, ForwardTarget, NamespaceName};
 use crate::daemon::daemon;
 use crate::down::down;
+use crate::proxy::proxy;
 use crate::up::up;
 
 mod config;
@@ -38,6 +39,17 @@ enum Commands {
     Down,
     /// Signal a running daemon to reload it's configuration
     Reload,
+    /// Create the configured namespaces
+    Proxy {
+        /// Namespace to proxy connections from, use "parent" to listen in the namespace this command was spawned into
+        source_namespace: NamespaceName,
+        /// Source address to listen on
+        source: ForwardSource,
+        /// Namespace to proxy connections to
+        target_namespace: NamespaceName,
+        /// Target address to connect to
+        target: ForwardTarget,
+    },
 }
 
 fn main() -> MainResult {
@@ -56,7 +68,10 @@ fn main() -> MainResult {
         Commands::Down => {
             down()
         }
-        Commands::Reload => reload()
+        Commands::Reload => reload(),
+        Commands::Proxy {source, target, source_namespace, target_namespace} => {
+            proxy(source_namespace, target_namespace, source, target)
+        },
     }
 }
 

src/proxy/mod.rs

@@ -3,17 +3,19 @@ mod tcp;
 use crate::config::{ForwardConfig, ForwardSource, ForwardTarget, NamespaceName};
 use crate::proxy::tcp::Proxy;
 use futures::future::AbortHandle;
+use main_error::MainResult;
 use nix::sched::{CloneFlags, setns};
+use nix::sys::signal::{SIGINT, kill};
+use nix::unistd::{Gid, Pid, Uid, setgid, setuid};
 use std::fs::{File, remove_file};
 use std::io::Error as IoError;
 use std::net::SocketAddr;
 use std::path::{Path, PathBuf};
-use std::sync::Arc;
+use std::process::{Child, Command};
-use std::sync::atomic::{AtomicU64, Ordering};
 use std::thread::spawn;
-use syscalls::{Sysno, syscall};
 use thiserror::Error;
 use tokio::runtime::Builder;
+use tokio::signal::ctrl_c;
 use tracing::error;
 use uzers::{get_group_by_name, get_user_by_name};
 
@@ -33,13 +35,14 @@ pub enum ProxyError {
     },
     #[error("Failed to open namespace file {}: {error:#}", path.display())]
     OpenNamespace { path: PathBuf, error: IoError },
+    #[error("Failed to spawn proxy: {error:#}")]
+    Spawn { error: std::io::Error },
 }
 
 pub struct ActiveProxy {
     pub source: ForwardSource,
     pub destination: ForwardTarget,
-    abort: AbortHandle,
+    child: Option<Child>,
-    pub stats: ProxyStats,
 }
 
 impl ActiveProxy {
@@ -47,89 +50,52 @@ impl ActiveProxy {
         config: &ForwardConfig,
         namespace: &NamespaceName,
     ) -> Result<ActiveProxy, ProxyError> {
-        let stats = ProxyStats::default();
-        let (abort, abort_reg) = AbortHandle::new_pair();
-
-        let destination = config.target.clone();
-        let run_stats = stats.clone();
-
-        let ns_handle = open_namespace(format!("/var/run/netns/{namespace}"))?;
-        let self_ns_handle = open_namespace("/proc/self/ns/net")?;
-
         let (listen_namespace, target_namespace) = if config.reverse {
-            (Some(ns_handle), self_ns_handle)
+            (namespace.as_ref(), "parent")
         } else {
-            (None, ns_handle)
+            ("parent", namespace.as_ref())
         };
 
-        let nobody_uid = get_user_by_name("nobody")
+        let mut command = Command::new("/proc/self/exe");
-            .map(|user| user.uid())
+        command
-            .unwrap_or(65534);
+            .arg("proxy")
-        let nobody_gid = get_group_by_name("nobody")
+            .arg(listen_namespace)
-            .map(|group| group.gid())
+            .arg(config.source.to_string())
-            .unwrap_or(65534);
+            .arg(target_namespace)
+            .arg(config.target.to_string());
 
-        let source = config.source.clone();
+        let child = command
-        spawn(move || {
+            .spawn()
-            let rt = match Builder::new_current_thread().enable_io().build() {
+            .map_err(|error| ProxyError::Spawn { error })?;
-                Ok(rt) => rt,
-                Err(error) => {
-                    error!(%error, "Error setting up tokio runtime");
-                    return;
-                }
-            };
-
-            rt.block_on(async {
-                if let Some(listen_namespace) = listen_namespace {
-                    if let Err(error) = setns(listen_namespace, CloneFlags::CLONE_NEWNET) {
-                        error!(%error, "Failed to join listen network namespace for proxy");
-                        return;
-                    }
-                }
-
-                let proxy = match Proxy::listen(&source) {
-                    Ok(proxy) => proxy,
-                    Err(error) => {
-                        error!(%error, "Failed to listen to {source}");
-                        return;
-                    }
-                };
-
-                if let Err(error) = setns(target_namespace, CloneFlags::CLONE_NEWNET) {
-                    error!(%error, "Failed to join target network namespace for proxy");
-                    return;
-                }
-
-                // raw syscall since the libc `setuid`/`setgui` set it for the entire process
-                unsafe {
-                    if let Err(error) = syscall!(Sysno::setgid, nobody_gid)
-                        .and_then(|_| syscall!(Sysno::setuid, nobody_uid))
-                    {
-                        error!(%error, "Failed drop privileges for proxy thread");
-                    }
-                }
-
-                proxy.run(destination, abort_reg, run_stats).await;
-            });
-        });
 
         Ok(ActiveProxy {
             source: config.source.clone(),
             destination: config.target.clone(),
-            abort,
+            child: Some(child),
-            stats,
         })
     }
 }
 
 impl Drop for ActiveProxy {
     fn drop(&mut self) {
-        if let ForwardSource::Unix(path) = &self.source {
+        let mut child = self.child.take().unwrap();
+        if let Err(error) = kill(Pid::from_raw(child.id() as i32), Some(SIGINT)) {
+            error!(%error, "failed to signal proxy process to stop");
+        }
+
+        let source = self.source.clone();
+        spawn(move || {
+            if let Err(error) = child.wait() {
+                error!(%error, "failed to wait for proxy process");
+            }
+
+            // we do this here, since the proxy process won't have permissions for it anymore
+            if let ForwardSource::Unix(path) = &source {
                 if let Err(error) = remove_file(path) {
                     error!(%error, "failed to remove unix socket");
                 }
             }
-        self.abort.abort();
+        });
     }
 }
 
@@ -139,53 +105,6 @@ impl PartialEq<ForwardConfig> for ActiveProxy {
     }
 }
 
-#[derive(Default, Clone)]
-pub struct ProxyStats {
-    open_connections: Arc<AtomicU64>,
-    total_connections: Arc<AtomicU64>,
-    /// Bytes proxied source -> destination
-    bytes_written: Arc<AtomicU64>,
-    /// Bytes proxied destination -> source
-    bytes_read: Arc<AtomicU64>,
-}
-
-impl ProxyStats {
-    pub fn open_connection(&self) {
-        self.open_connections.fetch_add(1, Ordering::Relaxed);
-        self.total_connections.fetch_add(1, Ordering::Relaxed);
-    }
-
-    pub fn close_connection(&self) {
-        self.open_connections.fetch_sub(1, Ordering::Relaxed);
-    }
-
-    pub fn open_connections(&self) -> u64 {
-        self.open_connections.load(Ordering::Relaxed)
-    }
-
-    pub fn total_connections(&self) -> u64 {
-        self.total_connections.load(Ordering::Relaxed)
-    }
-
-    pub fn add_read(&self, bytes: u64) {
-        self.bytes_read.fetch_add(bytes, Ordering::Relaxed);
-    }
-
-    pub fn add_written(&self, bytes: u64) {
-        self.bytes_written.fetch_add(bytes, Ordering::Relaxed);
-    }
-
-    /// Bytes proxied destination -> source
-    pub fn read(&self) -> u64 {
-        self.bytes_read.load(Ordering::Relaxed)
-    }
-
-    /// Bytes proxied source -> destination
-    pub fn written(&self) -> u64 {
-        self.bytes_written.load(Ordering::Relaxed)
-    }
-}
-
 fn open_namespace(path: impl AsRef<Path>) -> Result<File, ProxyError> {
     let path = path.as_ref();
     File::open(path).map_err(|error| ProxyError::OpenNamespace {
@@ -193,3 +112,80 @@ fn open_namespace(path: impl AsRef<Path>) -> Result<File, ProxyError> {
         path: path.into(),
     })
 }
+
+pub fn proxy(
+    source_namespace: NamespaceName,
+    target_namespace: NamespaceName,
+    source: ForwardSource,
+    target: ForwardTarget,
+) -> MainResult {
+    let (abort, abort_reg) = AbortHandle::new_pair();
+
+    let target_namespace = if target_namespace == "parent" {
+        open_namespace("/proc/self/ns/net")?
+    } else {
+        open_namespace(format!("/var/run/netns/{target_namespace}"))?
+    };
+
+    let listen_namespace = if source_namespace == "parent" {
+        None
+    } else {
+        Some(open_namespace(format!(
+            "/var/run/netns/{source_namespace}"
+        ))?)
+    };
+
+    let nobody_uid = Uid::from(
+        get_user_by_name("nobody")
+            .map(|user| user.uid())
+            .unwrap_or(65534),
+    );
+    let nobody_gid = Gid::from(
+        get_group_by_name("nobody")
+            .map(|group| group.gid())
+            .unwrap_or(65534),
+    );
+
+    let rt = match Builder::new_current_thread().enable_io().build() {
+        Ok(rt) => rt,
+        Err(error) => {
+            error!(%error, "Error setting up tokio runtime");
+            return Err(error.into());
+        }
+    };
+
+    rt.block_on(async {
+        if let Some(listen_namespace) = listen_namespace {
+            if let Err(error) = setns(listen_namespace, CloneFlags::CLONE_NEWNET) {
+                error!(%error, "Failed to join listen network namespace for proxy");
+                return Err(error.into());
+            }
+        }
+
+        let proxy = match Proxy::listen(&source) {
+            Ok(proxy) => proxy,
+            Err(error) => {
+                error!(%error, "Failed to listen to {source}");
+                return Err(error.into());
+            }
+        };
+
+        if let Err(error) = setns(target_namespace, CloneFlags::CLONE_NEWNET) {
+            error!(%error, "Failed to join target network namespace for proxy");
+            return Err(error.into());
+        }
+
+        if let Err(error) = setgid(nobody_gid).and_then(|_| setuid(nobody_uid)) {
+            error!(%error, "Failed to drop privileges");
+        }
+
+        tokio::spawn(async move {
+            let _ = ctrl_c().await;
+            abort.abort();
+        });
+
+        proxy.run(target, abort_reg).await;
+
+        Ok(())
+    })
+}

src/proxy/tcp.rs

@@ -1,6 +1,6 @@
 /// Loosely based on https://github.com/fooker/netns-proxy/blob/main/src/tcp.rs
 use crate::config::{ForwardTarget, ForwardSource};
-use crate::proxy::{ProxyError, ProxyStats};
+use crate::proxy::{ProxyError};
 use futures::TryStreamExt;
 use futures::stream::{AbortRegistration, Abortable};
 use std::fs::{remove_file, set_permissions};
@@ -61,14 +61,13 @@ impl Proxy {
         })
     }
 
-    pub async fn run(self, target: ForwardTarget, abort: AbortRegistration, stats: ProxyStats) {
+    pub async fn run(self, target: ForwardTarget, abort: AbortRegistration,) {
-        let proxy_stats = stats.clone();
         match self.socket {
             ProxyListener::Tcp(socket) => {
-                run_tcp(socket, target.addr, abort, proxy_stats).await
+                run_tcp(socket, target.addr, abort).await
             }
             ProxyListener::Unix(socket) => {
-                run_unix(socket, target.addr, abort, proxy_stats).await
+                run_unix(socket, target.addr, abort).await
             }
         }
     }
@@ -78,16 +77,14 @@ async fn run_tcp(
     socket: TcpListener,
     target: SocketAddr,
     abort: AbortRegistration,
-    stats: ProxyStats,
 ) {
     let accepts = TcpListenerStream::new(socket).map_err(|error| ProxyError::Accept { error });
     let mut accepts = pin!(Abortable::new(accepts, abort));
     while let Some(client) = accepts.next().await {
-        stats.open_connection();
         let result: Result<(), ProxyError> = async {
             let client = client?;
             let remote = client.peer_addr().ok();
-            proxy_stream(client, target, remote, stats.clone()).await
+            proxy_stream(client, target, remote).await
         }
         .await;
 
@@ -101,15 +98,13 @@ async fn run_unix(
     socket: UnixListener,
     target: SocketAddr,
     abort: AbortRegistration,
-    stats: ProxyStats,
 ) {
     let accepts = UnixListenerStream::new(socket).map_err(|error| ProxyError::Accept { error });
     let mut accepts = pin!(Abortable::new(accepts, abort));
     while let Some(client) = accepts.next().await {
-        stats.open_connection();
         let result: Result<(), ProxyError> = async {
             let client = client?;
-            proxy_stream(client, target, None, stats.clone()).await
+            proxy_stream(client, target, None).await
         }
         .await;
 
@@ -119,12 +114,11 @@ async fn run_unix(
     }
 }
 
-#[instrument(skip(stream, proxy))]
+#[instrument(skip(stream))]
 async fn proxy_stream<Stream>(
     mut stream: Stream,
     target: SocketAddr,
     remote: Option<SocketAddr>,
-    proxy: ProxyStats,
 ) -> Result<(), ProxyError>
 where
     Stream: AsyncRead + AsyncWrite + Unpin + Send + Sync + 'static,
@@ -143,10 +137,7 @@ where
 
     spawn(async move {
         match copy_bidirectional(&mut stream, &mut upstream).await {
-            Ok((written, read)) => {
+            Ok(_) => {
-                proxy.add_written(written);
-                proxy.add_read(read);
-                proxy.close_connection();
                 trace!("Upstream connection closed");
             }
             Err(err) => {