Add create-netns-only argument for debugging + firejail usage

USERGUIDE.md

@@ -21,6 +21,22 @@ entire shell sessions inside vopono.
 Note that the order of command-line arguments matters, as the `--dns`
 argument can take a list of DNS servers for example.
 
+### Creating only Network Namespace
+
+You can run vopono to create only the network namespace using the
+`--create-netns-only` argument, the application related arguments are
+then ignored (pass anything as the application name). This can be useful
+for debugging connection issues.
+
+This can also be used to launch an application without sudo via firejail
+- e.g. (where `none` is passed as the dummy application):
+
+```bash
+$ vopono -v exec --provider protonvpn --server japan --protocol openvpn --create-netns-only none
+2023-11-26T11:17:52.623Z INFO  vopono::exec > Created netns vo_pr_japan - will leave network namespace alive until ctrl+C received
+$ firejail --netns=vo_pr_japan firefox-developer-edition
+```
+
 ### Configuration file
 
 You can save default configuration options in the config file

src/args.rs

@@ -216,6 +216,10 @@ pub struct ExecCommand {
     /// Enable port forwarding for ProtonVPN connections
     #[clap(long = "protonvpn-port-forwarding")]
     pub protonvpn_port_forwarding: bool,
+
+    /// Only create network namespace (does not run application)
+    #[clap(long = "create-netns-only")]
+    pub create_netns_only: bool,
 }
 
 #[derive(Parser)]

src/exec.rs

@@ -150,6 +150,17 @@ pub fn exec(command: ExecCommand, uiclient: &dyn UiClient) -> anyhow::Result<()>
         command.protonvpn_port_forwarding
     };
 
+    // Create netns only
+    let create_netns_only = if !command.create_netns_only {
+        vopono_config_settings
+            .get("create-netns-only")
+            .map_err(|_e| anyhow!("Failed to read config file"))
+            .ok()
+            .unwrap_or(false)
+    } else {
+        command.create_netns_only
+    };
+
     // Assign DNS server from args or vopono config file
     let base_dns = command.dns.clone().or_else(|| {
         vopono_config_settings
@@ -551,15 +562,6 @@ pub fn exec(command: ExecCommand, uiclient: &dyn UiClient) -> anyhow::Result<()>
         vopono_core::util::open_ports(&ns, &[pmpc.local_port], firewall)?;
     }
 
-    let application = ApplicationWrapper::new(
-        &ns,
-        &command.application,
-        user,
-        group,
-        working_directory.map(PathBuf::from),
-        natpmpc,
-    )?;
-
     // Launch TCP proxy server on other threads if forwarding ports
     // TODO: Fix when running as root
     let mut proxy = Vec::new();
@@ -580,27 +582,46 @@ pub fn exec(command: ExecCommand, uiclient: &dyn UiClient) -> anyhow::Result<()>
         }
     }
 
-    let pid = application.handle.id();
-    info!(
-        "Application {} launched in network namespace {} with pid {}",
-        &command.application, &ns.name, pid
-    );
+    if !create_netns_only {
+        let application = ApplicationWrapper::new(
+            &ns,
+            &command.application,
+            user,
+            group,
+            working_directory.map(PathBuf::from),
+            natpmpc,
+        )?;
 
-    if let Some(pmpc) = application.protonvpn_port_forwarding.as_ref() {
-        info!("ProtonVPN Port Forwarding on port {}", pmpc.local_port)
-    }
-    let output = application.wait_with_output()?;
-    io::stdout().write_all(output.stdout.as_slice())?;
+        let pid = application.handle.id();
+        info!(
+            "Application {} launched in network namespace {} with pid {}",
+            &command.application, &ns.name, pid
+        );
 
-    // Allow daemons to leave namespace open
-    if vopono_core::util::check_process_running(pid) {
+        if let Some(pmpc) = application.protonvpn_port_forwarding.as_ref() {
+            info!("ProtonVPN Port Forwarding on port {}", pmpc.local_port)
+        }
+        let output = application.wait_with_output()?;
+        io::stdout().write_all(output.stdout.as_slice())?;
+
+        // Allow daemons to leave namespace open
+        if vopono_core::util::check_process_running(pid) {
+            info!(
+            "Process {} still running, assumed to be daemon - will leave network namespace {} alive until ctrl+C received",
+            pid, &ns.name
+        );
+            stay_alive(Some(pid), signals);
+        } else if command.keep_alive {
+            info!(
+                "Keep-alive flag active - will leave network namespace {} alive until ctrl+C received", &ns.name
+            );
+            stay_alive(None, signals);
+        }
+    } else {
         info!(
-            "Process {} still running, assumed to be daemon - will leave network namespace alive until ctrl+C received",
-            pid
+            "Created netns {} - will leave network namespace alive until ctrl+C received",
+            &ns.name
         );
-        stay_alive(Some(pid), signals);
-    } else if command.keep_alive {
-        info!("Keep-alive flag active - will leave network namespace alive until ctrl+C received");
         stay_alive(None, signals);
     }
 

vopono_core/src/network/shadowsocks.rs

@@ -16,7 +16,6 @@ use log::{debug, error};
 use rand::seq::SliceRandom;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
-use std::convert::TryFrom;
 use std::fs::read_to_string;
 use std::net::{IpAddr, Ipv4Addr};
 use std::path::Path;
@@ -95,9 +94,9 @@ pub fn uses_shadowsocks(openvpn_config: &Path) -> anyhow::Result<Option<(IpAddr,
     }
     debug!("socks-proxy detected, will launch Shadowsocks server");
     Ok(Some((
-        IpAddr::try_from(Ipv4Addr::from_str(
+        IpAddr::from(Ipv4Addr::from_str(
             cap.as_ref().unwrap().get(1).unwrap().as_str(),
-        )?)?,
+        )?),
         cap.unwrap().get(2).unwrap().as_str().parse::<u16>()?,
     )))
 }
@@ -113,9 +112,9 @@ pub fn get_routes_from_config(path: &Path) -> anyhow::Result<Vec<IpAddr>> {
     let caps = re.captures_iter(&file_string);
 
     for cap in caps {
-        output_vec.push(IpAddr::try_from(Ipv4Addr::from_str(
+        output_vec.push(IpAddr::from(Ipv4Addr::from_str(
             cap.get(1).unwrap().as_str(),
-        )?)?);
+        )?));
     }
 
     if output_vec.is_empty() {

vopono_core/src/util/mod.rs

@@ -353,8 +353,7 @@ pub fn elevate_privileges(askpass: bool) -> anyhow::Result<()> {
             .status()
             .context(format!("Executing sudo {} {:?}", sudo_flags, &args))?;
 
-        // Deprecated - do we need to handle flag here?
-        // cleanup::cleanup_signal(SIGINT)?;
+        // TODO: Could handle executing with non-sudo firejail here
 
         if terminated.load(Ordering::SeqCst) {
             // we received a sigint,