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|
mod network_manager;
mod resolvconf;
mod static_resolv_conf;
mod systemd_resolved;
use self::{
network_manager::NetworkManager, resolvconf::Resolvconf, static_resolv_conf::StaticResolvConf,
systemd_resolved::SystemdResolved,
};
use std::{
env,
fmt::{self, Display},
net::IpAddr,
};
use talpid_routing::RouteManagerHandle;
use super::ResolvedDnsConfig;
pub type Result<T> = std::result::Result<T, Error>;
/// Errors that can happen in the Linux DNS monitor
#[derive(thiserror::Error, Debug)]
pub enum Error {
/// Error in systemd-resolved DNS monitor
#[error("Error in systemd-resolved DNS monitor")]
SystemdResolved(#[from] systemd_resolved::Error),
/// Error in NetworkManager DNS monitor
#[error("Error in NetworkManager DNS monitor")]
NetworkManager(#[from] network_manager::Error),
/// Error in resolvconf DNS monitor
#[error("Error in resolvconf DNS monitor")]
Resolvconf(#[from] resolvconf::Error),
/// Error in static /etc/resolv.conf DNS monitor
#[error("Error in static /etc/resolv.conf DNS monitor")]
StaticResolvConf(#[from] static_resolv_conf::Error),
/// No suitable DNS monitor implementation detected
#[error("No suitable DNS monitor implementation detected")]
NoDnsMonitor,
}
pub struct DnsMonitor {
route_manager: RouteManagerHandle,
handle: tokio::runtime::Handle,
inner: Option<DnsMonitorHolder>,
}
impl super::DnsMonitorT for DnsMonitor {
type Error = Error;
fn new(handle: tokio::runtime::Handle, route_manager: RouteManagerHandle) -> Result<Self> {
Ok(DnsMonitor {
route_manager,
handle,
inner: None,
})
}
fn set(&mut self, interface: &str, config: ResolvedDnsConfig) -> Result<()> {
let servers = config.tunnel_config();
self.reset()?;
// Creating a new DNS monitor for each set, in case the system changed how it manages DNS.
let mut inner = DnsMonitorHolder::new()?;
if !servers.is_empty() {
inner.set(&self.handle, &self.route_manager, interface, servers)?;
self.inner = Some(inner);
}
Ok(())
}
fn reset(&mut self) -> Result<()> {
if let Some(mut inner) = self.inner.take() {
inner.reset(&self.handle)?;
}
Ok(())
}
}
pub enum DnsMonitorHolder {
SystemdResolved(SystemdResolved),
NetworkManager(NetworkManager),
Resolvconf(Resolvconf),
StaticResolvConf(StaticResolvConf),
}
impl fmt::Display for DnsMonitorHolder {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use self::DnsMonitorHolder::*;
let name = match self {
Resolvconf(..) => "resolvconf",
StaticResolvConf(..) => "/etc/resolv.conf",
SystemdResolved(..) => "systemd-resolved",
NetworkManager(..) => "NetworkManager",
};
f.write_str(name)
}
}
impl DnsMonitorHolder {
fn new() -> Result<Self> {
let dns_module = env::var_os("TALPID_DNS_MODULE");
let manager = match dns_module.as_ref().and_then(|value| value.to_str()) {
Some("static-file") => DnsMonitorHolder::StaticResolvConf(StaticResolvConf::new()?),
Some("resolvconf") => DnsMonitorHolder::Resolvconf(Resolvconf::new()?),
Some("systemd") => DnsMonitorHolder::SystemdResolved(SystemdResolved::new()?),
Some("network-manager") => DnsMonitorHolder::NetworkManager(NetworkManager::new()?),
Some(_) | None => Self::with_detected_dns_manager()?,
};
log::debug!("Managing DNS via {}", manager);
Ok(manager)
}
fn with_detected_dns_manager() -> Result<Self> {
fn log_err<E: Display>(method: &'static str) -> impl Fn(&E) {
move |err: &E| {
log::debug!("Can't manage DNS using {method}: {err}");
}
}
SystemdResolved::new()
.map(DnsMonitorHolder::SystemdResolved)
.inspect_err(log_err("systemd-resolved"))
.or_else(|_| {
NetworkManager::new()
.map(DnsMonitorHolder::NetworkManager)
.inspect_err(log_err("NetworkManager"))
})
.or_else(|_| {
Resolvconf::new()
.map(DnsMonitorHolder::Resolvconf)
.inspect_err(log_err("resolveconf"))
})
.or_else(|_| {
StaticResolvConf::new()
.map(DnsMonitorHolder::StaticResolvConf)
.inspect_err(log_err("/etc/resolv.conf"))
})
.map_err(|_| Error::NoDnsMonitor)
}
fn set(
&mut self,
handle: &tokio::runtime::Handle,
route_manager: &RouteManagerHandle,
interface: &str,
servers: &[IpAddr],
) -> Result<()> {
use self::DnsMonitorHolder::*;
match self {
Resolvconf(resolvconf) => resolvconf.set_dns(interface, servers)?,
StaticResolvConf(static_resolv_conf) => static_resolv_conf.set_dns(servers.to_vec())?,
SystemdResolved(systemd_resolved) => handle.block_on(systemd_resolved.set_dns(
route_manager.clone(),
interface,
servers,
))?,
NetworkManager(network_manager) => network_manager.set_dns(interface, servers)?,
}
Ok(())
}
fn reset(&mut self, handle: &tokio::runtime::Handle) -> Result<()> {
use self::DnsMonitorHolder::*;
match self {
Resolvconf(resolvconf) => resolvconf.reset()?,
StaticResolvConf(static_resolv_conf) => static_resolv_conf.reset()?,
SystemdResolved(systemd_resolved) => handle.block_on(systemd_resolved.reset())?,
NetworkManager(network_manager) => network_manager.reset()?,
}
Ok(())
}
}
/// Returns true if DnsMonitor will use NetworkManager to manage DNS.
pub fn will_use_nm() -> bool {
crate::dns::imp::SystemdResolved::new().is_err()
&& crate::dns::imp::NetworkManager::new().is_ok()
}
|
