refactor(core): separate portable core from native runtime (#2451)

Create easytier-core as the portable owner of configuration,
connectivity, tunnels, peer and routing state, gateways, management,
the data plane, and instance lifecycle. Keep operating-system
integration, native protocol engines, process startup, and presentation
in easytier behind explicit Host capability adapters.

Create easytier-proto to own schemas, generated RPC types, descriptors,
and feature-scoped protocol slices. Remove runtime protobuf reflection
from core while preserving unknown route-peer fields across forwarding.

Normalize instance construction through CoreInstance, CoreHostAdapters,
CoreProcessRuntime, and InstanceManager. Make the runtime config store
the only authoritative mutable configuration after startup.

Move the portable TCP/UDP data plane into core and extract a generic
OperationBroker for completion, cancellation, disposal, and capacity
accounting. Expose the session-based FFI v2 completion API and keep the
WASI guest ABI, wire schemas, and adapters with core.

Migrate CLI, GUI, web, FFI, Android JNI, OHOS, uptime, and mobile
consumers to the shared manager and core state. Add explicit user/web
config ownership and revision-aware web reconciliation.

Preserve configuration, wire, and management behavior while fixing
regressions discovered by the full platform and integration matrix:

- inherit advertised relay capabilities in foreign networks;
- refresh OSPF peer state immediately after runtime config changes;
- restore CLI GlobalCtx event output without forcing GUI logging;
- retain legacy encryption names and standalone RPC tunnel metadata;
- restore ICMP host composition and fragmented UDP handling;
- use portable 64-bit atomics on 32-bit MIPS targets; and
- retain discarded operations until late cancellation completes.

Validate the refactor across 45 GitHub checks, including Linux, macOS,
Windows, FreeBSD, web, GUI, Android, OHOS, feature profiles, and
three-node and subnet-proxy integration tests.

BREAKING CHANGE: internal Rust module paths are not preserved. Legacy
native data-plane APIs are replaced by the session-based FFI v2 API.
The dedicated Android data-plane wrapper is removed.

easytier/src/host_runtime.rs

@@ -0,0 +1,235 @@
+use std::{
+    net::{IpAddr, SocketAddr, SocketAddrV4, SocketAddrV6},
+    sync::{Arc, OnceLock},
+};
+
+use async_trait::async_trait;
+use easytier_core::{
+    connectivity::{composite::ConnectorRuntime, transport::ConnectedByteStream},
+    host::dns::{DnsQuery, DnsRecordResolver, DnsResolver, DnsSrvRecord},
+    socket::{
+        SocketContext,
+        tcp::{
+            TcpConnectOptions, TcpListenOptions, TcpSocketPurpose, VirtualTcpListenerFactory,
+            VirtualTcpSocketFactory,
+        },
+        udp::{PreferredIpv6Source, UdpBindOptions, VirtualUdpSocketFactory},
+    },
+};
+
+use crate::{
+    common::{
+        dns::RuntimeDnsResolver,
+        netns::NetNS,
+        network::{collect_interfaces, collect_local_ip_addrs},
+    },
+    proto::peer_rpc::GetIpListResponse,
+    socket::{
+        tcp::{RuntimeTcpListener, RuntimeTcpSocket},
+        udp::{RuntimeUdpSocket, RuntimeUdpSocketFactory},
+    },
+};
+
+/// Process-wide native implementation of the host capabilities consumed by core.
+///
+/// Instance-specific policy is carried by each request's socket context. Keeping
+/// this object stateless prevents a socket operation from capturing one
+/// instance's namespace or mark.
+#[derive(Debug)]
+pub struct NativeHostRuntime {
+    udp_sockets: RuntimeUdpSocketFactory,
+    dns: RuntimeDnsResolver,
+}
+
+static NATIVE_HOST_RUNTIME: OnceLock<Arc<NativeHostRuntime>> = OnceLock::new();
+
+pub(crate) fn native_host_runtime() -> Arc<NativeHostRuntime> {
+    NATIVE_HOST_RUNTIME
+        .get_or_init(|| {
+            Arc::new(NativeHostRuntime {
+                udp_sockets: RuntimeUdpSocketFactory::new(),
+                dns: RuntimeDnsResolver::new(),
+            })
+        })
+        .clone()
+}
+
+#[async_trait]
+impl VirtualTcpSocketFactory for NativeHostRuntime {
+    type Socket = RuntimeTcpSocket;
+
+    async fn connect_tcp(&self, options: TcpConnectOptions) -> anyhow::Result<Self::Socket> {
+        #[cfg(feature = "faketcp")]
+        if options.purpose == TcpSocketPurpose::FakeTcp {
+            let remote_addr = options.remote_addr;
+            let socket_mark = options.bind.context.socket_mark;
+            let net_ns = NetNS::from_socket_context(&options.bind.context);
+            let socket =
+                crate::socket::fake_tcp::connect_socket(remote_addr, socket_mark, net_ns).await?;
+            return Ok(RuntimeTcpSocket::from_fake_tcp(socket));
+        }
+
+        #[cfg(not(feature = "faketcp"))]
+        if options.purpose == TcpSocketPurpose::FakeTcp {
+            anyhow::bail!("FakeTCP socket support is disabled")
+        }
+
+        crate::socket::tcp::connect_tcp(options)
+            .await
+            .map_err(anyhow::Error::from)
+    }
+}
+
+#[async_trait]
+impl ConnectorRuntime for NativeHostRuntime {
+    async fn connect_byte_stream(
+        &self,
+        url: &url::Url,
+    ) -> anyhow::Result<ConnectedByteStream<RuntimeTcpSocket>> {
+        #[cfg(unix)]
+        if url.scheme() == "unix" {
+            let stream = tokio::net::UnixStream::connect(url.path()).await?;
+            let local_url = stream
+                .local_addr()
+                .ok()
+                .and_then(crate::socket::tcp::url_from_unix_socket_addr);
+            return Ok(ConnectedByteStream::new(
+                RuntimeTcpSocket::from_unix(stream),
+                local_url,
+                url.clone(),
+                Some(url.clone()),
+            ));
+        }
+
+        anyhow::bail!("unsupported runtime byte stream: {url}")
+    }
+
+    async fn local_addr_for_remote(
+        &self,
+        remote_addr: SocketAddr,
+        context: SocketContext,
+    ) -> anyhow::Result<SocketAddr> {
+        let socket = NetNS::from_socket_context(&context).run(|| -> anyhow::Result<_> {
+            let (domain, bind_addr) = match remote_addr {
+                SocketAddr::V4(_) => (
+                    socket2::Domain::IPV4,
+                    SocketAddr::V4(SocketAddrV4::new(std::net::Ipv4Addr::UNSPECIFIED, 0)),
+                ),
+                SocketAddr::V6(_) => (
+                    socket2::Domain::IPV6,
+                    SocketAddr::V6(SocketAddrV6::new(std::net::Ipv6Addr::UNSPECIFIED, 0, 0, 0)),
+                ),
+            };
+            let socket =
+                socket2::Socket::new(domain, socket2::Type::DGRAM, Some(socket2::Protocol::UDP))?;
+            crate::tunnel::common::apply_socket_mark(&socket, context.socket_mark)?;
+            socket.set_nonblocking(true)?;
+            socket.bind(&socket2::SockAddr::from(bind_addr))?;
+            Ok(std::net::UdpSocket::from(socket))
+        })?;
+        let socket = tokio::net::UdpSocket::from_std(socket)?;
+        socket.connect(remote_addr).await?;
+        Ok(socket.local_addr()?)
+    }
+
+    async fn preferred_ipv6_source(
+        &self,
+        ip: std::net::Ipv6Addr,
+        context: SocketContext,
+    ) -> Option<PreferredIpv6Source> {
+        collect_interfaces(NetNS::from_socket_context(&context), false)
+            .await
+            .into_iter()
+            .find(|interface| {
+                interface
+                    .ips
+                    .iter()
+                    .any(|local| matches!(local.ip(), IpAddr::V6(local_ip) if local_ip == ip))
+            })
+            .map(|interface| PreferredIpv6Source {
+                ip,
+                ifindex: interface.index,
+            })
+    }
+
+    async fn collect_ip_addrs(&self, context: &SocketContext) -> GetIpListResponse {
+        collect_local_ip_addrs(NetNS::from_socket_context(context)).await
+    }
+}
+
+impl NativeHostRuntime {
+    pub(crate) fn is_local_ip(&self, ip: &IpAddr, context: &SocketContext) -> bool {
+        NetNS::from_socket_context(context)
+            .run(|| std::net::UdpSocket::bind(format!("{ip}:0")).is_ok())
+    }
+}
+
+#[async_trait]
+impl VirtualTcpListenerFactory for NativeHostRuntime {
+    type Listener = RuntimeTcpListener;
+
+    async fn bind_tcp(&self, options: TcpListenOptions) -> anyhow::Result<Arc<Self::Listener>> {
+        Ok(Arc::new(crate::socket::tcp::bind_tcp_listener(options)?))
+    }
+}
+
+#[async_trait]
+impl VirtualUdpSocketFactory for NativeHostRuntime {
+    type Socket = RuntimeUdpSocket;
+
+    async fn bind_udp(&self, options: UdpBindOptions) -> anyhow::Result<Arc<Self::Socket>> {
+        let socket = self.udp_sockets.bind_udp(options).await?;
+        #[cfg(target_os = "windows")]
+        crate::arch::windows::disable_connection_reset(socket.socket().as_ref())?;
+        Ok(socket)
+    }
+}
+
+#[async_trait]
+impl DnsResolver for NativeHostRuntime {
+    async fn resolve(&self, query: DnsQuery) -> anyhow::Result<Vec<IpAddr>> {
+        self.dns.resolve(query).await
+    }
+}
+
+#[async_trait]
+impl DnsRecordResolver for NativeHostRuntime {
+    async fn resolve_txt(&self, query: DnsQuery) -> anyhow::Result<String> {
+        self.dns.resolve_txt(query).await
+    }
+
+    async fn resolve_srv(&self, query: DnsQuery) -> anyhow::Result<Vec<DnsSrvRecord>> {
+        self.dns.resolve_srv(query).await
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn native_host_runtime_is_process_wide() {
+        assert!(Arc::ptr_eq(&native_host_runtime(), &native_host_runtime()));
+    }
+
+    #[test]
+    fn native_local_ip_probe_uses_process_runtime() {
+        assert!(native_host_runtime().is_local_ip(
+            &IpAddr::V4(std::net::Ipv4Addr::LOCALHOST),
+            &SocketContext::default(),
+        ));
+    }
+
+    #[tokio::test]
+    async fn native_route_probe_uses_remote_address_family() {
+        let local_addr = native_host_runtime()
+            .local_addr_for_remote(
+                SocketAddr::from(([127, 0, 0, 1], 9)),
+                SocketContext::default(),
+            )
+            .await
+            .unwrap();
+
+        assert!(local_addr.is_ipv4());
+    }
+}