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feat(net/socket): implement net reuse port #2173

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20d7f90
feat(net): allow multiple TCP sockets to share a port in port manager
mistcoversmyeyes Aug 5, 2026
0ba7aa5
feat(net): add SO_REUSEPORT socket option to TCP sockets
mistcoversmyeyes Aug 5, 2026
636beff
feat(net): thread reuseport flags through TCP bind/listen
mistcoversmyeyes Aug 5, 2026
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107 changes: 66 additions & 41 deletions kernel/src/net/socket/inet/common/port.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ use system_error::SystemError;
use crate::{
arch::rand::rand,
libs::mutex::Mutex,
process::{ProcessManager, RawPid},
process::ProcessManager,
};

use super::Types::{self, *};
Expand All @@ -16,8 +16,8 @@ use super::Types::{self, *};
/// 如果 TCP/UDP 的 socket 绑定了某个端口，它会在对应的表中记录，以检测端口冲突。
#[derive(Debug)]
pub struct PortManager {
// TCP 端口记录表
tcp_port_table: Mutex<HashMap<u16, RawPid>>,
// TCP 端口记录表。一个端口可以有多条绑定记录（SO_REUSEPORT/SO_REUSEADDR 共享）。
tcp_port_table: Mutex<HashMap<u16, Vec<TcpPortBinding>>>,
// UDP 端口记录表
udp_port_table: Mutex<HashMap<u16, Vec<UdpPortBinding>>>,
}
Expand Down Expand Up @@ -95,16 +95,23 @@ impl PortManager {
}

#[inline]
pub fn bind_ephemeral_port(&self, socket_type: Types) -> Result<u16, SystemError> {
pub fn bind_tcp_ephemeral_port(
&self,
addr: IpAddress,
reuseaddr: bool,
reuseport: bool,
iface_nic_id: usize,
handle: smoltcp::iface::SocketHandle,
) -> Result<u16, SystemError> {
let (min, max) = Self::local_port_range();
let range = (max - min) as u32 + 1;
if range == 0 {
return Err(SystemError::EINVAL);
}
let mut remaining = range;
while remaining > 0 {
let port = self.get_ephemeral_port(socket_type)?;
match self.bind_port(socket_type, port) {
let port = self.get_ephemeral_port(Types::Tcp)?;
match self.bind_tcp_port(port, addr, reuseaddr, reuseport, iface_nic_id, handle) {
Ok(()) => return Ok(port),
Err(SystemError::EADDRINUSE) => {
// Race: another thread grabbed the port after we checked.
Expand Down Expand Up @@ -146,44 +153,52 @@ impl PortManager {
Err(SystemError::EADDRINUSE)
}

/// @brief 检测给定端口是否已被占用，如果未被占用则在 TCP 对应的表中记录
/// TCP: 绑定端口，支持 SO_REUSEADDR/SO_REUSEPORT。
///
/// UDP 复用逻辑请使用 `bind_udp_port`
pub fn bind_port(&self, socket_type: Types, port: u16) -> Result<(), SystemError> {
if port > 0 {
match socket_type {
Udp => {
let mut guard = self.udp_port_table.lock();
if guard.get(&port).is_some() {
return Err(SystemError::EADDRINUSE);
}
guard.insert(port, Vec::new());
}
Tcp => {
let mut guard = self.tcp_port_table.lock();
if guard.get(&port).is_some() {
return Err(SystemError::EADDRINUSE);
}
guard.insert(port, ProcessManager::current_pid());
}
_ => {}
};
/// 一条绑定记录以 `(iface_nic_id, handle)` 唯一标识（BoundInner 身份），
/// 因此多个进程/多个 socket 可以共享同一端口而不需要调用方保存额外 id。
pub fn bind_tcp_port(
&self,
port: u16,
addr: IpAddress,
reuseaddr: bool,
reuseport: bool,
iface_nic_id: usize,
handle: smoltcp::iface::SocketHandle,
) -> Result<(), SystemError> {
if port == 0 {
return Err(SystemError::EINVAL);
}
let mut guard = self.tcp_port_table.lock();
let bindings = guard.entry(port).or_default();
for binding in bindings.iter() {
if !addrs_conflict(addr, binding.addr) {
continue;
}
let share_ok = (reuseport && binding.reuseport) || (reuseaddr && binding.reuseaddr);
if !share_ok {
return Err(SystemError::EADDRINUSE);
}
}
return Ok(());
bindings.push(TcpPortBinding {
addr,
reuseaddr,
reuseport,
iface_nic_id,
handle,
});
Ok(())
}

/// @brief 在对应的端口记录表中将端口和 socket 解绑
/// should call this function when socket is closed or aborted
pub fn unbind_port(&self, socket_type: Types, port: u16) {
match socket_type {
Udp => {
self.udp_port_table.lock().remove(&port);
}
Tcp => {
self.tcp_port_table.lock().remove(&port);
/// TCP: 解绑端口（按 BoundInner 身份）
pub fn unbind_tcp_port(&self, port: u16, iface_nic_id: usize, handle: smoltcp::iface::SocketHandle) {
let mut guard = self.tcp_port_table.lock();
if let Some(list) = guard.get_mut(&port) {
list.retain(|b| b.iface_nic_id != iface_nic_id || b.handle != handle);
if list.is_empty() {
guard.remove(&port);
}
_ => {}
};
}
}

/// UDP: 绑定端口，支持 SO_REUSEADDR/SO_REUSEPORT
Expand All @@ -201,7 +216,7 @@ impl PortManager {
let mut guard = self.udp_port_table.lock();
let bindings = guard.entry(port).or_default();
for binding in bindings.iter() {
if !udp_addrs_conflict(addr, binding.addr) {
if !addrs_conflict(addr, binding.addr) {
continue;
}
let share_ok = (reuseport && binding.reuseport) || (reuseaddr && binding.reuseaddr);
Expand Down Expand Up @@ -238,8 +253,18 @@ struct UdpPortBinding {
bind_id: usize,
}

/// TCP 端口绑定记录。`(iface_nic_id, handle)` 是绑定的 BoundInner 身份。
#[derive(Debug, Clone)]
struct TcpPortBinding {
addr: IpAddress,
reuseaddr: bool,
reuseport: bool,
iface_nic_id: usize,
handle: smoltcp::iface::SocketHandle,
}

#[inline]
fn udp_addrs_conflict(a: IpAddress, b: IpAddress) -> bool {
fn addrs_conflict(a: IpAddress, b: IpAddress) -> bool {
if a.version() != b.version() {
return false;
}
Expand Down
2 changes: 1 addition & 1 deletion kernel/src/net/socket/inet/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ pub mod stream;
pub mod syscall;

pub use common::BoundInner;
pub use common::Types;

pub use datagram::UdpSocket;
pub use raw::RawSocket;

Expand Down
71 changes: 51 additions & 20 deletions kernel/src/net/socket/inet/stream/inner.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use crate::filesystem::epoll::EPollEventType;
use crate::libs::mutex::Mutex;
use crate::libs::rwsem::RwSem;
use crate::net::socket::{self, inet::Types};
use crate::net::socket::{self};
use crate::process::namespace::net_namespace::NetNamespace;
use crate::syscall::user_buffer::UserBuffer;
use alloc::boxed::Box;
Expand Down Expand Up @@ -51,11 +51,13 @@ fn new_smoltcp_socket() -> smoltcp::socket::tcp::Socket<'static> {

fn new_listen_smoltcp_socket<T>(
local_endpoint: T,
reuseport: bool,
) -> Result<smoltcp::socket::tcp::Socket<'static>, SystemError>
where
T: Into<smoltcp::wire::IpListenEndpoint>,
{
let mut socket = new_smoltcp_socket();
socket.set_reuseport(reuseport);
socket.listen(local_endpoint).map_err(|e| match e {
tcp::ListenError::InvalidState => SystemError::EINVAL, // TODO: Check is right impl
tcp::ListenError::Unaddressable => SystemError::EADDRINUSE,
Expand Down Expand Up @@ -112,6 +114,8 @@ impl Init {
self,
local_endpoint: smoltcp::wire::IpEndpoint,
netns: Arc<NetNamespace>,
reuseaddr: bool,
reuseport: bool,
) -> Result<Self, (Self, SystemError)> {
match self {
Init::Unbound((socket, ver)) => {
Expand All @@ -128,7 +132,13 @@ impl Init {

// Handle ephemeral port assignment (port 0)
let bind_port = if local_endpoint.port == 0 {
match bound.port_manager().bind_ephemeral_port(Types::Tcp) {
match bound.port_manager().bind_tcp_ephemeral_port(
local_endpoint.addr,
reuseaddr,
reuseport,
bound.iface().nic_id(),
bound.handle(),
) {
Ok(port) => port,
Err(err) => {
let smoltcp::socket::Socket::Tcp(socket) = bound.into_socket() else {
Expand All @@ -138,10 +148,14 @@ impl Init {
}
}
} else {
if let Err(err) = bound
.port_manager()
.bind_port(Types::Tcp, local_endpoint.port)
{
if let Err(err) = bound.port_manager().bind_tcp_port(
local_endpoint.port,
local_endpoint.addr,
reuseaddr,
reuseport,
bound.iface().nic_id(),
bound.handle(),
) {
let smoltcp::socket::Socket::Tcp(socket) = bound.into_socket() else {
unreachable!("TCP BoundInner should contain a TCP socket");
};
Expand Down Expand Up @@ -178,7 +192,13 @@ impl Init {
return Err((Self::Unbound((Box::new(socket), ver)), err))
}
};
let bound_port = match bound.port_manager().bind_ephemeral_port(Types::Tcp) {
let bound_port = match bound.port_manager().bind_tcp_ephemeral_port(
address,
false,
false,
bound.iface().nic_id(),
bound.handle(),
) {
Ok(port) => port,
Err(err) => {
let smoltcp::socket::Socket::Tcp(socket) = bound.into_socket() else {
Expand Down Expand Up @@ -230,6 +250,8 @@ impl Init {
self,
backlog: usize,
netns: Arc<NetNamespace>,
reuseaddr: bool,
reuseport: bool,
) -> Result<Listening, (Self, SystemError)> {
// If unbound, auto-bind to INADDR_ANY:ephemeral (Linux compat).
let bound_self = if matches!(self, Init::Unbound(_)) {
Expand All @@ -246,7 +268,7 @@ impl Init {
}
};
let auto_bind_ep = smoltcp::wire::IpEndpoint::new(unspec_addr, 0);
match self.bind(auto_bind_ep, netns.clone()) {
match self.bind(auto_bind_ep, netns.clone(), reuseaddr, reuseport) {
Ok(bound) => bound,
Err((init, err)) => return Err((init, err)),
}
Expand Down Expand Up @@ -298,7 +320,7 @@ impl Init {
continue; // primary inner already covers this iface
}
let new_listen = socket::inet::BoundInner::bind_on_iface(
new_listen_smoltcp_socket(listen_addr)?,
new_listen_smoltcp_socket(listen_addr, reuseport)?,
iface.clone(),
inner.netns(),
)?;
Expand All @@ -308,7 +330,7 @@ impl Init {
let remaining = backlog.saturating_sub(1 + inners.len());
for _ in 0..remaining {
let new_listen = socket::inet::BoundInner::bind_on_iface(
new_listen_smoltcp_socket(listen_addr)?,
new_listen_smoltcp_socket(listen_addr, reuseport)?,
inner.iface().clone(),
inner.netns(),
)?;
Expand All @@ -319,7 +341,7 @@ impl Init {
let additional_sockets = backlog.saturating_sub(1);
for _ in 0..additional_sockets {
let new_listen = socket::inet::BoundInner::bind(
new_listen_smoltcp_socket(listen_addr)?,
new_listen_smoltcp_socket(listen_addr, reuseport)?,
listen_addr
.addr
.as_ref()
Expand All @@ -337,6 +359,7 @@ impl Init {
}

if let Err(err) = inner.with_mut::<smoltcp::socket::tcp::Socket, _, _>(|socket| {
socket.set_reuseport(reuseport);
socket.listen(listen_addr).map_err(|err| match err {
tcp::ListenError::InvalidState => SystemError::EINVAL,
tcp::ListenError::Unaddressable => SystemError::EINVAL,
Expand All @@ -350,14 +373,17 @@ impl Init {
inners,
connect: AtomicUsize::new(0),
listen_addr,
reuseport,
});
}

pub(super) fn close(&self) {
match self {
Init::Unbound(_) => {}
Init::Bound((inner, endpoint)) => {
inner.port_manager().unbind_port(Types::Tcp, endpoint.port);
inner
.port_manager()
.unbind_tcp_port(endpoint.port, inner.iface().nic_id(), inner.handle());
inner.with_mut::<smoltcp::socket::tcp::Socket, _, _>(|socket| socket.close());
}
}
Expand Down Expand Up @@ -434,9 +460,11 @@ impl Connecting {
| ConnectResult::ShutdownReset
| ConnectResult::ShutdownResetConsumed => {
// unbind port
self.inner
.port_manager()
.unbind_port(Types::Tcp, self.local.port);
self.inner.port_manager().unbind_tcp_port(
self.local.port,
self.inner.iface().nic_id(),
self.inner.handle(),
);
let socket = self.inner.into_socket();
let socket = match socket {
smoltcp::socket::Socket::Tcp(s) => s,
Expand Down Expand Up @@ -690,6 +718,7 @@ pub struct Listening {
pub inners: Vec<socket::inet::BoundInner>,
connect: AtomicUsize,
listen_addr: smoltcp::wire::IpListenEndpoint,
reuseport: bool,
}

impl Listening {
Expand All @@ -716,13 +745,13 @@ impl Listening {
// where each interface has its own listen socket in the smoltcp SocketSet.
let mut new_listen = if self.listen_addr.addr.is_none() {
socket::inet::BoundInner::bind_on_iface(
new_listen_smoltcp_socket(self.listen_addr)?,
new_listen_smoltcp_socket(self.listen_addr, self.reuseport)?,
connected.iface().clone(),
connected.netns(),
)?
} else {
socket::inet::BoundInner::bind(
new_listen_smoltcp_socket(self.listen_addr)?,
new_listen_smoltcp_socket(self.listen_addr, self.reuseport)?,
self.listen_addr
.addr
.as_ref()
Expand Down Expand Up @@ -782,12 +811,14 @@ impl Listening {
// (pushed last during listen() construction). We must unbind from its
// port_manager, not inners[0] which may belong to a different iface for
// INADDR_ANY listeners.
self.inners
let owner = self
.inners
.last()
.expect("Listening socket must have at least one inner")
.expect("Listening socket must have at least one inner");
owner
.iface()
.port_manager()
.unbind_port(Types::Tcp, port);
.unbind_tcp_port(port, owner.iface().nic_id(), owner.handle());
}

pub fn release(&mut self) {
Expand Down
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