refactor(iroh-net): make region ids always be u16

iroh-net/src/hp/cfg.rs

@@ -81,7 +81,7 @@ pub struct NetInfo {
     /// connected to multiple DERP servers (to send to other nodes)
     /// but PreferredDERP is the instance number that the node
     /// subscribes to traffic at. Zero means disconnected or unknown.
-    pub preferred_derp: usize,
+    pub preferred_derp: u16,
 
     /// LinkType is the current link type, if known.
     pub link_type: Option<LinkType>,
@@ -116,7 +116,7 @@ impl NetInfo {
 pub enum LinkType {
     Wired,
     Wifi,
-    //LTE, 4G, 3G, etc
+    /// LTE, 4G, 3G, etc
     Mobile,
 }
 
@@ -137,7 +137,7 @@ pub struct PingResult {
     /// The ip:port if direct UDP was used. It is not currently set for TSMP pings.
     pub endpoint: Option<SocketAddr>,
     /// Non-zero DERP region ID if DERP was used. It is not currently set for TSMP pings.
-    pub derp_region_id: Option<usize>,
+    pub derp_region_id: Option<u16>,
     /// The three-letter region code corresponding to derp_region_id. It is not currently set for TSMP pings.
     pub derp_region_code: Option<String>,
     /// Whether the ping request error is due to it being a ping to the local node.

iroh-net/src/hp/derp/map.rs

@@ -12,12 +12,12 @@ use url::Url;
 /// Configuration of all the Derp servers that can be used.
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
 pub struct DerpMap {
-    pub regions: HashMap<usize, DerpRegion>,
+    pub regions: HashMap<u16, DerpRegion>,
 }
 
 impl DerpMap {
     /// Returns the sorted region IDs.
-    pub fn region_ids(&self) -> Vec<usize> {
+    pub fn region_ids(&self) -> Vec<u16> {
         let mut ids: Vec<_> = self.regions.keys().copied().collect();
         ids.sort();
         ids
@@ -69,7 +69,7 @@ impl fmt::Display for DerpMap {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct DerpRegion {
     /// A unique integer for a geographic region.
-    pub region_id: usize,
+    pub region_id: u16,
     pub nodes: Vec<DerpNode>,
     pub avoid: bool,
     pub region_code: String,
@@ -78,7 +78,7 @@ pub struct DerpRegion {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct DerpNode {
     pub name: String,
-    pub region_id: usize,
+    pub region_id: u16,
     pub host_name: Url,
     pub stun_only: bool,
     pub stun_port: u16,

iroh-net/src/hp/magicsock/conn.rs

@@ -210,7 +210,7 @@ impl Inner {
     pub(super) async fn get_derp_region(&self, region: u16) -> Option<DerpRegion> {
         match &*self.derp_map.read().await {
             None => None,
-            Some(ref derp_map) => derp_map.regions.get(&usize::from(region)).cloned(),
+            Some(ref derp_map) => derp_map.regions.get(&region).cloned(),
         }
     }
 
@@ -1524,7 +1524,7 @@ impl Actor {
             ni.preferred_derp = self.pick_derp_fallback().await;
         }
 
-        if !self.set_nearest_derp(ni.preferred_derp.try_into()?).await {
+        if !self.set_nearest_derp(ni.preferred_derp).await {
             ni.preferred_derp = 0;
         }
 
@@ -1557,7 +1557,7 @@ impl Actor {
                 .as_ref()
                 .expect("already checked")
                 .regions
-                .get(&usize::from(derp_num))
+                .get(&derp_num)
             {
                 Some(dr) => {
                     info!("home is now derp-{} ({})", derp_num, dr.region_code);
@@ -1580,7 +1580,7 @@ impl Actor {
     /// Returns a non-zero but deterministic DERP node to
     /// connect to. This is only used if netcheck couldn't find the nearest one
     /// For instance, if UDP is blocked and thus STUN latency checks aren't working
-    async fn pick_derp_fallback(&self) -> usize {
+    async fn pick_derp_fallback(&self) -> u16 {
         let ids = {
             let derp_map = self.conn.derp_map.read().await;
             if derp_map.is_none() {
@@ -1609,7 +1609,7 @@ impl Actor {
 
         let my_derp = self.conn.my_derp();
         if my_derp > 0 {
-            return my_derp.into();
+            return my_derp;
         }
 
         let mut rng = rand::rngs::StdRng::seed_from_u64(0);

iroh-net/src/hp/magicsock/derp_actor.rs

@@ -206,10 +206,10 @@ impl DerpActor {
                             continue;
                         }
                     }
-                    if u16::try_from(rid).expect("region too large") == self.conn.my_derp() {
+                    if rid == self.conn.my_derp() {
                         self.conn.set_my_derp(0);
                     }
-                    to_close.push(u16::try_from(rid).expect("too large"));
+                    to_close.push(rid);
                 }
             }
         }
@@ -249,12 +249,7 @@ impl DerpActor {
                 warn!("DERP is disabled");
                 return;
             }
-            if !derp_map
-                .as_ref()
-                .unwrap()
-                .regions
-                .contains_key(&usize::from(region_id))
-            {
+            if !derp_map.as_ref().unwrap().regions.contains_key(&region_id) {
                 warn!("unknown region id {}", region_id);
                 return;
             }

iroh-net/src/hp/magicsock/endpoint.rs

@@ -625,7 +625,7 @@ impl Endpoint {
 
                 if !self.pending_cli_pings.is_empty() {
                     let ep = sp.to;
-                    let region_id = usize::from(ep.port());
+                    let region_id = ep.port();
                     // FIXME: this creates a deadlock as it needs to interact with the run loop in the conn::Actor
                     // let region_code = self.get_derp_region(region_id).await.map(|r| r.region_code);
 

iroh-net/src/hp/netcheck.rs

@@ -99,13 +99,13 @@ pub struct Report {
     /// None means not checked.
     pub pcp: Option<bool>,
     /// or 0 for unknown
-    pub preferred_derp: usize,
+    pub preferred_derp: u16,
     /// keyed by DERP Region ID
-    pub region_latency: HashMap<usize, Duration>,
+    pub region_latency: HashMap<u16, Duration>,
     /// keyed by DERP Region ID
-    pub region_v4_latency: HashMap<usize, Duration>,
+    pub region_v4_latency: HashMap<u16, Duration>,
     /// keyed by DERP Region ID
-    pub region_v6_latency: HashMap<usize, Duration>,
+    pub region_v6_latency: HashMap<u16, Duration>,
     /// ip:port of global IPv4
     pub global_v4: Option<SocketAddr>,
     /// `[ip]:port` of global IPv6
@@ -298,7 +298,7 @@ async fn measure_https_latency(_reg: &DerpRegion) -> Result<(Duration, IpAddr)>
 /// return a "204 No Content" response and checking if that's what we get.
 ///
 /// The boolean return is whether we think we have a captive portal.
-async fn check_captive_portal(dm: &DerpMap, preferred_derp: Option<usize>) -> Result<bool> {
+async fn check_captive_portal(dm: &DerpMap, preferred_derp: Option<u16>) -> Result<bool> {
     // If we have a preferred DERP region with more than one node, try
     // that; otherwise, pick a random one not marked as "Avoid".
     let preferred_derp = if preferred_derp.is_none()
@@ -1031,7 +1031,7 @@ fn probe_would_help(report: &Report, probe: &Probe, node: &DerpNode) -> bool {
     false
 }
 
-fn update_latency(m: &mut HashMap<usize, Duration>, region_id: usize, d: Duration) {
+fn update_latency(m: &mut HashMap<u16, Duration>, region_id: u16, d: Duration) {
     let prev = m.entry(region_id).or_insert(d);
     if d < *prev {
         *prev = d;
@@ -1049,7 +1049,7 @@ fn named_node<'a>(dm: &'a DerpMap, node_name: &str) -> Option<&'a DerpNode> {
     None
 }
 
-fn max_duration_value(m: &HashMap<usize, Duration>) -> Duration {
+fn max_duration_value(m: &HashMap<u16, Duration>) -> Duration {
     m.values().max().cloned().unwrap_or_default()
 }
 
@@ -1918,7 +1918,7 @@ mod tests {
             let mut report = Report::default();
             for (s, d) in a {
                 assert!(s.starts_with('d'), "invalid derp server key");
-                let region_id: usize = s[1..].parse().unwrap();
+                let region_id: u16 = s[1..].parse().unwrap();
                 report
                     .region_latency
                     .insert(region_id, Duration::from_secs(d));
@@ -1935,7 +1935,7 @@ mod tests {
             name: &'static str,
             steps: Vec<Step>,
             /// want PreferredDERP on final step
-            want_derp: usize,
+            want_derp: u16,
             // wanted len(c.prev)
             want_prev_len: usize,
         }

iroh-net/src/hp/stun.rs

@@ -166,7 +166,7 @@ pub mod test {
         let mut m = DerpMap::default();
 
         for (i, addr) in stun.enumerate() {
-            let region_id = i + 1;
+            let region_id = (i + 1) as u16;
             let host = addr.ip();
             let port = addr.port();