src/config/options.rs

@@ -19,6 +19,9 @@ pub struct ConfigOptsBase {
     pub refresh_time: Option<u16>,
     /// STUN server [default: stun.nextcloud.com:443]
     pub stun_server: Option<String>,
+    /// IPv6-only mode (disables IGD, IPv4 firewall and IPv4 address autodiscovery) [default: false]
+    #[serde(default)]
+    pub ipv6_only: bool,
 }
 
 /// ACME configuration options

src/config/options_test.rs

@@ -63,15 +63,13 @@ fn ok_from_iter_minimal_valid_options() {
         rt_config.firewall.refresh_time,
         Duration::from_secs(REFRESH_TIME.into())
     );
-    assert!(rt_config.igd.private_ip.is_none());
+    let igd = rt_config.igd.unwrap();
+    assert!(igd.private_ip.is_none());
     assert_eq!(
-        rt_config.igd.expiration_time,
+        igd.expiration_time,
         Duration::from_secs(EXPIRATION_TIME.into())
     );
-    assert_eq!(
-        rt_config.igd.refresh_time,
-        Duration::from_secs(REFRESH_TIME.into())
-    );
+    assert_eq!(igd.refresh_time, Duration::from_secs(REFRESH_TIME.into()));
 }
 
 #[test]
@@ -117,10 +115,11 @@ fn ok_from_iter_all_valid_options() {
         opts.get(&"DIPLONAT_CONSUL_URL".to_string()).unwrap()
     );
     assert_eq!(rt_config.firewall.refresh_time, refresh_time);
+    let igd = rt_config.igd.unwrap();
     assert_eq!(
-        &rt_config.igd.private_ip.unwrap().to_string(),
+        &igd.private_ip.unwrap().to_string(),
         opts.get(&"DIPLONAT_PRIVATE_IP".to_string()).unwrap()
     );
-    assert_eq!(rt_config.igd.expiration_time, expiration_time);
-    assert_eq!(rt_config.igd.refresh_time, refresh_time);
+    assert_eq!(igd.expiration_time, expiration_time);
+    assert_eq!(igd.refresh_time, refresh_time);
 }

src/config/runtime.rs

@@ -26,6 +26,7 @@ pub struct RuntimeConfigConsul {
 
 #[derive(Debug)]
 pub struct RuntimeConfigFirewall {
+    pub ipv6_only: bool,
     pub refresh_time: Duration,
 }
 
@@ -38,7 +39,7 @@ pub struct RuntimeConfigIgd {
 
 #[derive(Debug)]
 pub struct RuntimeConfigStun {
-    pub stun_server_v4: SocketAddr,
+    pub stun_server_v4: Option<SocketAddr>,
     pub stun_server_v6: SocketAddr,
     pub refresh_time: Duration,
 }
@@ -48,7 +49,7 @@ pub struct RuntimeConfig {
     pub acme: Option<RuntimeConfigAcme>,
     pub consul: RuntimeConfigConsul,
     pub firewall: RuntimeConfigFirewall,
-    pub igd: RuntimeConfigIgd,
+    pub igd: Option<RuntimeConfigIgd>,
     pub stun: RuntimeConfigStun,
 }
 
@@ -57,7 +58,10 @@ impl RuntimeConfig {
         let acme = RuntimeConfigAcme::new(opts.acme)?;
         let consul = RuntimeConfigConsul::new(opts.consul)?;
         let firewall = RuntimeConfigFirewall::new(&opts.base)?;
-        let igd = RuntimeConfigIgd::new(&opts.base)?;
+        let igd = match opts.base.ipv6_only {
+            false => Some(RuntimeConfigIgd::new(&opts.base)?),
+            true => None,
+        };
         let stun = RuntimeConfigStun::new(&opts.base)?;
 
         Ok(Self {
@@ -131,7 +135,10 @@ impl RuntimeConfigFirewall {
         let refresh_time =
             Duration::from_secs(opts.refresh_time.unwrap_or(super::REFRESH_TIME).into());
 
-        Ok(Self { refresh_time })
+        Ok(Self {
+            refresh_time,
+            ipv6_only: opts.ipv6_only,
+        })
     }
 }
 
@@ -189,9 +196,15 @@ impl RuntimeConfigStun {
         let refresh_time =
             Duration::from_secs(opts.refresh_time.unwrap_or(super::REFRESH_TIME).into());
 
+        let stun_server_v4 = match opts.ipv6_only {
+            false => Some(
+                stun_server_v4.ok_or(anyhow!("Unable to resolve STUN server's IPv4 address"))?,
+            ),
+            true => None,
+        };
+
         Ok(Self {
-            stun_server_v4: stun_server_v4
-                .ok_or(anyhow!("Unable to resolve STUN server's IPv4 address"))?,
+            stun_server_v4,
             stun_server_v6: stun_server_v6
                 .ok_or(anyhow!("Unable to resolve STUN server's IPv6 address"))?,
             refresh_time,

src/diplonat.rs

@@ -9,7 +9,7 @@ use crate::{
 pub struct Diplonat {
     consul: ConsulActor,
     firewall: FirewallActor,
-    igd: IgdActor,
+    igd: Option<IgdActor>,
     stun: StunActor,
 }
 
@@ -20,16 +20,26 @@ impl Diplonat {
 
         let ca = ConsulActor::new(&rt_cfg.consul, &rt_cfg.consul.node_name);
 
-        let fw = FirewallActor::new(rt_cfg.firewall.refresh_time, &ca.rx_open_ports).await?;
-
-        let ia = IgdActor::new(
-            rt_cfg.igd.private_ip,
-            rt_cfg.igd.refresh_time,
-            rt_cfg.igd.expiration_time,
+        let fw = FirewallActor::new(
+            rt_cfg.firewall.ipv6_only,
+            rt_cfg.firewall.refresh_time,
             &ca.rx_open_ports,
         )
         .await?;
 
+        let ia = match rt_cfg.igd {
+            Some(igdc) => Some(
+                IgdActor::new(
+                    igdc.private_ip,
+                    igdc.refresh_time,
+                    igdc.expiration_time,
+                    &ca.rx_open_ports,
+                )
+                .await?,
+            ),
+            None => None,
+        };
+
         let sa = StunActor::new(&rt_cfg.consul, &rt_cfg.stun, &rt_cfg.consul.node_name);
 
         let ctx = Self {
@@ -43,9 +53,17 @@ impl Diplonat {
     }
 
     pub async fn listen(&mut self) -> Result<()> {
+        let igd_opt = &mut self.igd;
+
         try_join!(
             self.consul.listen(),
-            self.igd.listen(),
+            async {
+                if let Some(igd) = igd_opt {
+                    igd.listen().await
+                } else {
+                    Ok(())
+                }
+            },
             self.firewall.listen(),
             self.stun.listen(),
         )?;

src/fw_actor.rs

@@ -12,7 +12,7 @@ use tokio::{
 use crate::{fw, messages};
 
 pub struct FirewallActor {
-    pub ipt_v4: iptables::IPTables,
+    pub ipt_v4: Option<iptables::IPTables>,
     pub ipt_v6: iptables::IPTables,
     rx_ports: watch::Receiver<messages::PublicExposedPorts>,
     last_ports: messages::PublicExposedPorts,
@@ -21,18 +21,24 @@ pub struct FirewallActor {
 
 impl FirewallActor {
     pub async fn new(
+        ipv6_only: bool,
         refresh: Duration,
         rxp: &watch::Receiver<messages::PublicExposedPorts>,
     ) -> Result<Self> {
         let ctx = Self {
-            ipt_v4: iptables::new(false)?,
+            ipt_v4: match ipv6_only {
+                false => Some(iptables::new(false)?),
+                true => None,
+            },
             ipt_v6: iptables::new(true)?,
             rx_ports: rxp.clone(),
             last_ports: messages::PublicExposedPorts::new(),
             refresh,
         };
 
-        fw::setup(&ctx.ipt_v4)?;
+        if let Some(ipt_v4) = &ctx.ipt_v4 {
+            fw::setup(ipt_v4)?;
+        }
         fw::setup(&ctx.ipt_v6)?;
 
         return Ok(ctx);
@@ -62,29 +68,35 @@ impl FirewallActor {
     }
 
     pub async fn do_fw_update(&self) -> Result<()> {
-        for ipt in [&self.ipt_v4, &self.ipt_v6] {
-            let curr_opened_ports = fw::get_opened_ports(ipt)?;
-
-            let diff_tcp = self
-                .last_ports
-                .tcp_ports
-                .difference(&curr_opened_ports.tcp_ports)
-                .copied()
-                .collect::<HashSet<u16>>();
-            let diff_udp = self
-                .last_ports
-                .udp_ports
-                .difference(&curr_opened_ports.udp_ports)
-                .copied()
-                .collect::<HashSet<u16>>();
-
-            let ports_to_open = messages::PublicExposedPorts {
-                tcp_ports: diff_tcp,
-                udp_ports: diff_udp,
-            };
-
-            fw::open_ports(ipt, ports_to_open)?;
+        if let Some(ipt_v4) = &self.ipt_v4 {
+            self.do_fw_update_on(ipt_v4).await?;
         }
+        self.do_fw_update_on(&self.ipt_v6).await?;
+        Ok(())
+    }
+
+    pub async fn do_fw_update_on(&self, ipt: &iptables::IPTables) -> Result<()> {
+        let curr_opened_ports = fw::get_opened_ports(ipt)?;
+
+        let diff_tcp = self
+            .last_ports
+            .tcp_ports
+            .difference(&curr_opened_ports.tcp_ports)
+            .copied()
+            .collect::<HashSet<u16>>();
+        let diff_udp = self
+            .last_ports
+            .udp_ports
+            .difference(&curr_opened_ports.udp_ports)
+            .copied()
+            .collect::<HashSet<u16>>();
+
+        let ports_to_open = messages::PublicExposedPorts {
+            tcp_ports: diff_tcp,
+            udp_ports: diff_udp,
+        };
+
+        fw::open_ports(ipt, ports_to_open)?;
 
         return Ok(());
     }

src/stun_actor.rs

@@ -11,7 +11,7 @@ use crate::consul;
 pub struct StunActor {
     node: String,
     consul: consul::Consul,
-    stun_server_v4: SocketAddr,
+    stun_server_v4: Option<SocketAddr>,
     stun_server_v6: SocketAddr,
     refresh_time: Duration,
 }
@@ -19,7 +19,7 @@ pub struct StunActor {
 #[derive(Serialize, Deserialize, Debug)]
 pub struct AutodiscoverResult {
     pub timestamp: u64,
-    pub address: IpAddr,
+    pub address: Option<IpAddr>,
 }
 
 impl StunActor {
@@ -28,7 +28,10 @@ impl StunActor {
         stun_config: &RuntimeConfigStun,
         node: &str,
     ) -> Self {
-        assert!(stun_config.stun_server_v4.is_ipv4());
+        assert!(stun_config
+            .stun_server_v4
+            .map(|x| x.is_ipv4())
+            .unwrap_or(true));
         assert!(stun_config.stun_server_v6.is_ipv6());
 
         Self {
@@ -42,7 +45,11 @@ impl StunActor {
 
     pub async fn listen(&mut self) -> Result<()> {
         loop {
-            if let Err(e) = self.autodiscover_ip(self.stun_server_v4).await {
+            let ipv4_result = match self.stun_server_v4 {
+                Some(stun_server_v4) => self.autodiscover_ip(stun_server_v4).await,
+                None => self.autodiscover_none_ipv4().await,
+            };
+            if let Err(e) = ipv4_result {
                 error!("Unable to autodiscover IPv4 address: {}", e);
             }
             if let Err(e) = self.autodiscover_ip(self.stun_server_v6).await {
@@ -75,10 +82,24 @@ impl StunActor {
             .kv_put(
                 &consul_key,
                 serde_json::to_vec(&AutodiscoverResult {
-                    timestamp: SystemTime::now()
-                        .duration_since(SystemTime::UNIX_EPOCH)?
-                        .as_secs(),
-                    address: discovered_addr,
+                    timestamp: timestamp(),
+                    address: Some(discovered_addr),
+                })?,
+            )
+            .await?;
+
+        Ok(())
+    }
+
+    async fn autodiscover_none_ipv4(&self) -> Result<()> {
+        let consul_key = format!("diplonat/autodiscovery/ipv4/{}", self.node);
+
+        self.consul
+            .kv_put(
+                &consul_key,
+                serde_json::to_vec(&AutodiscoverResult {
+                    timestamp: timestamp(),
+                    address: None,
                 })?,
             )
             .await?;
@@ -101,3 +122,10 @@ async fn get_mapped_addr(stun_server: SocketAddr, binding_addr: SocketAddr) -> R
         .ok_or(anyhow!("no XorMappedAddress found in STUN response"))?;
     Ok(xor_mapped_addr)
 }
+
+fn timestamp() -> u64 {
+    SystemTime::now()
+        .duration_since(SystemTime::UNIX_EPOCH)
+        .expect("clock error")
+        .as_secs()
+}