add support for setting up routing inside the netns

src/config/mod.rs

@@ -5,10 +5,15 @@ mod target;
 pub use crate::config::name::{DeviceName, NamespaceName};
 pub use crate::config::source::ForwardSource;
 pub use crate::config::target::ForwardTarget;
-use serde::Deserialize;
+use cidr::AnyIpCidr;
+use serde::de::Error;
+use serde::{Deserialize, Deserializer};
+use std::borrow::Cow;
 use std::collections::HashSet;
+use std::fmt::{Display, Formatter};
 use std::fs::read_to_string;
 use std::path::{Path, PathBuf};
+use std::str::FromStr;
 use thiserror::Error;
 use toml::from_str;
 
@@ -84,6 +89,8 @@ pub struct NamespaceConfig {
     pub forward: Vec<ForwardConfig>,
     #[serde(default)]
     pub devices: Vec<DeviceName>,
+    #[serde(default, rename = "route")]
+    pub routes: Vec<RouteConfig>,
 }
 
 #[derive(Deserialize, Debug)]
@@ -94,6 +101,27 @@ pub struct ForwardConfig {
     pub reverse: bool,
 }
 
+#[derive(Deserialize, Debug, PartialEq, Clone)]
+pub struct RouteConfig {
+    #[serde(deserialize_with = "parse_cidr")]
+    pub destination: AnyIpCidr,
+    pub device: DeviceName,
+}
+
+impl Display for RouteConfig {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{} dev {}", self.destination, self.device)
+    }
+}
+
+fn parse_cidr<'de, D: Deserializer<'de>>(deserializer: D) -> Result<AnyIpCidr, D::Error> {
+    let str = Cow::<'de, str>::deserialize(deserializer)?;
+    match str.as_ref() {
+        "default" => Ok(AnyIpCidr::Any),
+        str => AnyIpCidr::from_str(str).map_err(D::Error::custom),
+    }
+}
+
 #[derive(Debug, Error)]
 pub enum ConfigError {
     #[error("Error while reading config from {}: {error:#}", path.display())]