fix(dns): resolve hostnames via the OS resolver instead of pure DNS

hickory_resolver's TokioResolver only consults /etc/resolv.conf and
queries upstream DNS servers — which means it can't see /etc/hosts,
mDNS (Avahi/Bonjour), NetBIOS, or anything else in the system's full
name-resolution stack. On a typical home LAN there's no DNS server
that knows about peer machine names, so users had to fall back to
typing IP addresses, which broke the moment they moved their setup
to a different network.

Swap to tokio::net::lookup_host, which calls getaddrinfo (or
GetAddrInfoEx on Windows). That walks /etc/nsswitch.conf on Linux
(picking up Avahi-resolved .local names, /etc/hosts, and DNS), uses
Bonjour for .local on macOS, and the full Windows resolver on
Windows. A Bonjour hostname like "JKMBP-M4-Max.local" now resolves
on every modern network without explicit configuration; the user
can carry their two machines between LANs and the connection still
finds them.

Drop the hickory-resolver dependency entirely — it's no longer
needed. ServiceError::Dns also goes away; lookup failures surface as
io::Error which is already covered by ServiceError::Io.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Cargo.lock

@@ -549,30 +549,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "critical-section"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
-
-[[package]]
-name = "crossbeam-channel"
-version = "0.5.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "82b8f8f868b36967f9606790d1903570de9ceaf870a7bf9fbbd3016d636a2cb2"
-dependencies = [
- "crossbeam-utils",
-]
-
-[[package]]
-name = "crossbeam-epoch"
-version = "0.9.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
-dependencies = [
- "crossbeam-utils",
-]
-
 [[package]]
 name = "crossbeam-utils"
 version = "0.8.21"
@@ -586,7 +562,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0dc92fb57ca44df6db8059111ab3af99a63d5d0f8375d9972e319a379c6bab76"
 dependencies = [
  "generic-array",
- "rand_core 0.6.4",
+ "rand_core",
  "subtle",
  "zeroize",
 ]
@@ -598,7 +574,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78c8292055d1c1df0cce5d180393dc8cce0abec0a7102adb6c7b1eef6016d60a"
 dependencies = [
  "generic-array",
- "rand_core 0.6.4",
+ "rand_core",
  "typenum",
 ]
 
@@ -735,7 +711,7 @@ dependencies = [
  "hkdf",
  "pem-rfc7468",
  "pkcs8",
- "rand_core 0.6.4",
+ "rand_core",
  "sec1",
  "subtle",
  "zeroize",
@@ -747,18 +723,6 @@ version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "66b7e2430c6dff6a955451e2cfc438f09cea1965a9d6f87f7e3b90decc014099"
 
-[[package]]
-name = "enum-as-inner"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1e6a265c649f3f5979b601d26f1d05ada116434c87741c9493cb56218f76cbc"
-dependencies = [
- "heck",
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "enumflags2"
 version = "0.7.12"
@@ -852,7 +816,7 @@ version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c0b50bfb653653f9ca9095b427bed08ab8d75a137839d9ad64eb11810d5b6393"
 dependencies = [
- "rand_core 0.6.4",
+ "rand_core",
  "subtle",
 ]
 
@@ -1281,7 +1245,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f0f9ef7462f7c099f518d754361858f86d8a07af53ba9af0fe635bbccb151a63"
 dependencies = [
  "ff",
- "rand_core 0.6.4",
+ "rand_core",
  "subtle",
 ]
 
@@ -1395,52 +1359,6 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
-[[package]]
-name = "hickory-proto"
-version = "0.25.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8a6fe56c0038198998a6f217ca4e7ef3a5e51f46163bd6dd60b5c71ca6c6502"
-dependencies = [
- "async-trait",
- "cfg-if",
- "data-encoding",
- "enum-as-inner",
- "futures-channel",
- "futures-io",
- "futures-util",
- "idna",
- "ipnet",
- "once_cell",
- "rand 0.9.2",
- "ring",
- "thiserror 2.0.18",
- "tinyvec",
- "tokio",
- "tracing",
- "url",
-]
-
-[[package]]
-name = "hickory-resolver"
-version = "0.25.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc62a9a99b0bfb44d2ab95a7208ac952d31060efc16241c87eaf36406fecf87a"
-dependencies = [
- "cfg-if",
- "futures-util",
- "hickory-proto",
- "ipconfig",
- "moka",
- "once_cell",
- "parking_lot",
- "rand 0.9.2",
- "resolv-conf",
- "smallvec",
- "thiserror 2.0.18",
- "tokio",
- "tracing",
-]
-
 [[package]]
 name = "hkdf"
 version = "0.12.4"
@@ -1713,19 +1631,6 @@ dependencies = [
  "thiserror 2.0.18",
 ]
 
-[[package]]
-name = "ipconfig"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4d40460c0ce33d6ce4b0630ad68ff63d6661961c48b6dba35e5a4d81cfb48222"
-dependencies = [
- "socket2",
- "widestring",
- "windows-registry",
- "windows-result 0.4.1",
- "windows-sys 0.61.2",
-]
-
 [[package]]
 name = "ipnet"
 version = "2.12.0"
@@ -1845,7 +1750,6 @@ dependencies = [
  "clap",
  "env_logger",
  "futures",
- "hickory-resolver",
  "input-capture",
  "input-emulation",
  "input-event",
@@ -2096,23 +2000,6 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
-[[package]]
-name = "moka"
-version = "0.12.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "957228ad12042ee839f93c8f257b62b4c0ab5eaae1d4fa60de53b27c9d7c5046"
-dependencies = [
- "crossbeam-channel",
- "crossbeam-epoch",
- "crossbeam-utils",
- "equivalent",
- "parking_lot",
- "portable-atomic",
- "smallvec",
- "tagptr",
- "uuid",
-]
-
 [[package]]
 name = "nix"
 version = "0.26.4"
@@ -2242,10 +2129,6 @@ name = "once_cell"
 version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
-dependencies = [
- "critical-section",
- "portable-atomic",
-]
 
 [[package]]
 name = "once_cell_polyfill"
@@ -2530,18 +2413,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
 dependencies = [
  "libc",
- "rand_chacha 0.3.1",
- "rand_core 0.6.4",
-]
-
-[[package]]
-name = "rand"
-version = "0.9.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
-dependencies = [
- "rand_chacha 0.9.0",
- "rand_core 0.9.5",
+ "rand_chacha",
+ "rand_core",
 ]
 
 [[package]]
@@ -2551,17 +2424,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
 dependencies = [
  "ppv-lite86",
- "rand_core 0.6.4",
-]
-
-[[package]]
-name = "rand_chacha"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
-dependencies = [
- "ppv-lite86",
- "rand_core 0.9.5",
+ "rand_core",
 ]
 
 [[package]]
@@ -2573,15 +2436,6 @@ dependencies = [
  "getrandom 0.2.17",
 ]
 
-[[package]]
-name = "rand_core"
-version = "0.9.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
-dependencies = [
- "getrandom 0.3.4",
-]
-
 [[package]]
 name = "rcgen"
 version = "0.13.2"
@@ -2644,12 +2498,6 @@ dependencies = [
  "tokio",
 ]
 
-[[package]]
-name = "resolv-conf"
-version = "0.7.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e061d1b48cb8d38042de4ae0a7a6401009d6143dc80d2e2d6f31f0bdd6470c7"
-
 [[package]]
 name = "rfc6979"
 version = "0.4.0"
@@ -2929,7 +2777,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77549399552de45a898a580c1b41d445bf730df867cc44e6c0233bbc4b8329de"
 dependencies = [
  "digest",
- "rand_core 0.6.4",
+ "rand_core",
 ]
 
 [[package]]
@@ -3017,12 +2865,6 @@ dependencies = [
  "version-compare",
 ]
 
-[[package]]
-name = "tagptr"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
-
 [[package]]
 name = "target-lexicon"
 version = "0.13.3"
@@ -3125,21 +2967,6 @@ dependencies = [
  "zerovec",
 ]
 
-[[package]]
-name = "tinyvec"
-version = "1.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3e61e67053d25a4e82c844e8424039d9745781b3fc4f32b8d55ed50f5f667ef3"
-dependencies = [
- "tinyvec_macros",
-]
-
-[[package]]
-name = "tinyvec_macros"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
-
 [[package]]
 name = "tokio"
 version = "1.51.1"
@@ -3417,7 +3244,6 @@ version = "1.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5ac8b6f42ead25368cf5b098aeb3dc8a1a2c05a3eee8a9a1a68c640edbfc79d9"
 dependencies = [
- "getrandom 0.4.2",
  "js-sys",
  "serde_core",
  "wasm-bindgen",
@@ -3658,8 +3484,8 @@ dependencies = [
  "p384",
  "pem",
  "portable-atomic",
- "rand 0.8.5",
- "rand_core 0.6.4",
+ "rand",
+ "rand_core",
  "rcgen",
  "ring",
  "rustls",
@@ -3690,18 +3516,12 @@ dependencies = [
  "log",
  "nix",
  "portable-atomic",
- "rand 0.8.5",
+ "rand",
  "thiserror 1.0.69",
  "tokio",
  "winapi",
 ]
 
-[[package]]
-name = "widestring"
-version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72069c3113ab32ab29e5584db3c6ec55d416895e60715417b5b883a357c3e471"
-
 [[package]]
 name = "winapi"
 version = "0.3.9"
@@ -3836,17 +3656,6 @@ dependencies = [
  "windows-link 0.1.3",
 ]
 
-[[package]]
-name = "windows-registry"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02752bf7fbdcce7f2a27a742f798510f3e5ad88dbe84871e5168e2120c3d5720"
-dependencies = [
- "windows-link 0.2.1",
- "windows-result 0.4.1",
- "windows-strings 0.5.1",
-]
-
 [[package]]
 name = "windows-result"
 version = "0.3.4"
@@ -4186,7 +3995,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c7e468321c81fb07fa7f4c636c3972b9100f0346e5b6a9f2bd0603a52f7ed277"
 dependencies = [
  "curve25519-dalek",
- "rand_core 0.6.4",
+ "rand_core",
  "serde",
  "zeroize",
 ]

Cargo.toml

@@ -36,7 +36,6 @@ lan-mouse-ipc = { path = "lan-mouse-ipc", version = "0.3.0" }
 lan-mouse-proto = { path = "lan-mouse-proto", version = "0.3.0" }
 shadow-rs = { version = "1.2.0", features = ["metadata"] }
 
-hickory-resolver = "0.25.2"
 toml = "0.8"
 toml_edit = { version = "0.22", features = ["serde"] }
 serde = { version = "1.0", features = ["derive"] }

src/dns.rs

@@ -1,9 +1,9 @@
-use std::{collections::HashMap, net::IpAddr};
+use std::{collections::HashMap, io, net::IpAddr};
 
 use local_channel::mpsc::{Receiver, Sender, channel};
+use tokio::net::lookup_host;
 use tokio::task::{JoinHandle, spawn_local};
 
-use hickory_resolver::{ResolveError, TokioResolver};
 use tokio_util::sync::CancellationToken;
 
 use lan_mouse_ipc::ClientHandle;
@@ -22,11 +22,10 @@ struct DnsRequest {
 
 pub(crate) enum DnsEvent {
     Resolving(ClientHandle),
-    Resolved(ClientHandle, String, Result<Vec<IpAddr>, ResolveError>),
+    Resolved(ClientHandle, String, io::Result<Vec<IpAddr>>),
 }
 
 struct DnsTask {
-    resolver: TokioResolver,
     request_rx: Receiver<DnsRequest>,
     event_tx: Sender<DnsEvent>,
     cancellation_token: CancellationToken,
@@ -34,14 +33,12 @@ struct DnsTask {
 }
 
 impl DnsResolver {
-    pub(crate) fn new() -> Result<Self, ResolveError> {
-        let resolver = TokioResolver::builder_tokio()?.build();
+    pub(crate) fn new() -> io::Result<Self> {
         let (request_tx, request_rx) = channel();
         let (event_tx, event_rx) = channel();
         let cancellation_token = CancellationToken::new();
         let dns_task = DnsTask {
             active_tasks: Default::default(),
-            resolver,
             request_rx,
             event_tx,
             cancellation_token: cancellation_token.clone(),
@@ -97,15 +94,13 @@ impl DnsTask {
 
             /* spawn task for dns request */
             let event_tx = self.event_tx.clone();
-            let resolver = self.resolver.clone();
             let cancellation_token = self.cancellation_token.clone();
 
             let task = tokio::task::spawn_local(async move {
                 tokio::select! {
-                    ips = resolver.lookup_ip(&hostname) => {
-                       let ips = ips.map(|ips| ips.iter().collect::<Vec<_>>());
+                    result = resolve_hostname(&hostname) => {
                        event_tx
-                           .send(DnsEvent::Resolved(handle, hostname, ips))
+                           .send(DnsEvent::Resolved(handle, hostname, result))
                            .expect("channel closed");
                     }
                     _ = cancellation_token.cancelled() => {},
@@ -115,3 +110,18 @@ impl DnsTask {
         }
     }
 }
+
+/// Resolve `hostname` via the operating system's full name-resolution
+/// stack (`getaddrinfo` on Unix, GetAddrInfoEx on Windows). This walks
+/// `/etc/nsswitch.conf` on Linux — picking up mDNS via Avahi, /etc/hosts,
+/// and DNS — and uses Bonjour for `.local` names on macOS. Pure-DNS
+/// resolvers like hickory miss all of those, which is why a Bonjour
+/// hostname (e.g. `JKMBP-M4-Max.local`) wouldn't resolve before.
+///
+/// Port `0` is a placeholder — `lookup_host` requires `host:port` but we
+/// only care about the IPs at this stage; the actual port is appended at
+/// connection time.
+async fn resolve_hostname(hostname: &str) -> io::Result<Vec<IpAddr>> {
+    let addrs = lookup_host((hostname, 0)).await?;
+    Ok(addrs.map(|sa| sa.ip()).collect())
+}

src/service.rs

@@ -9,7 +9,6 @@ use crate::{
     listen::{LanMouseListener, ListenerCreationError},
 };
 use futures::StreamExt;
-use hickory_resolver::ResolveError;
 use lan_mouse_ipc::{
     AsyncFrontendListener, ClientHandle, FrontendEvent, FrontendRequest, IpcError,
     IpcListenerCreationError, Position, Status,
@@ -26,8 +25,6 @@ use tokio::{process::Command, signal, sync::Notify};
 
 #[derive(Debug, Error)]
 pub enum ServiceError {
-    #[error(transparent)]
-    Dns(#[from] ResolveError),
     #[error(transparent)]
     IpcListen(#[from] IpcListenerCreationError),
     #[error(transparent)]