chore: remove UDP support and unused future roadmap

UDP was never implemented (listener returned ErrUnsupported, dialer was
commented out). Remove all dead UDP code paths and return an explicit
error for UDP networks in CreateListener. Also remove the Future
roadmap section from READMEs as there is no plan to support these.

Author: xiaost

README.md

@@ -53,12 +53,6 @@ For more information, please refer to [Document](#document).
     - TCP, Unix Domain Socket
     - Linux, macOS (operating system)
 
-* **Future**
-    - [io_uring][io_uring]
-    - Shared Memory IPC
-    - TLS
-    - UDP
-
 * **Unsupported**
     - Windows (operating system)
 
@@ -100,4 +94,3 @@ More benchmarks reference [kitex-benchmark][kitex-benchmark] and [hertz-benchmar
 [LinkBuffer]: nocopy_linkbuffer.go
 [gopool]: https://github.com/bytedance/gopkg/tree/develop/util/gopool
 [mcache]: https://github.com/bytedance/gopkg/tree/develop/lang/mcache
-[io_uring]: https://github.com/axboe/liburing

README_CN.md

@@ -48,12 +48,6 @@ goroutine，大幅增加调度开销。此外，[net.Conn][net.Conn] 没有提
     - 支持 TCP，Unix Domain Socket
     - 支持 Linux，macOS（操作系统）
 
-* **即将开源**
-    - [io_uring][io_uring]
-    - Shared Memory IPC
-    - 支持 TLS
-    - 支持 UDP
-
 * **不被支持**
     - Windows（操作系统）
 
@@ -93,4 +87,3 @@ goroutine，大幅增加调度开销。此外，[net.Conn][net.Conn] 没有提
 [LinkBuffer]: nocopy_linkbuffer.go
 [gopool]: https://github.com/bytedance/gopkg/tree/develop/util/gopool
 [mcache]: https://github.com/bytedance/gopkg/tree/develop/lang/mcache
-[io_uring]: https://github.com/axboe/liburing

net_dialer.go

@@ -70,7 +70,6 @@ func (d *dialer) DialConnection(network, address string, timeout time.Duration)
 	switch network {
 	case "tcp", "tcp4", "tcp6":
 		return d.dialTCP(ctx, network, address)
-	// case "udp", "udp4", "udp6":  // TODO: unsupported now
 	case "unix", "unixgram", "unixpacket":
 		raddr := &UnixAddr{
 			UnixAddr: net.UnixAddr{Name: address, Net: network},

net_listener.go

@@ -26,9 +26,8 @@ import (
 
 // CreateListener return a new Listener.
 func CreateListener(network, addr string) (l Listener, err error) {
-	if network == "udp" {
-		// TODO: udp listener.
-		return udpListener(network, addr)
+	if network == "udp" || network == "udp4" || network == "udp6" {
+		return nil, Exception(ErrUnsupported, "UDP")
 	}
 	// tcp, tcp4, tcp6, unix
 	ln, err := net.Listen(network, addr)
@@ -53,42 +52,17 @@ func ConvertListener(l net.Listener) (nl Listener, err error) {
 	return ln, syscall.SetNonblock(ln.fd, true)
 }
 
-// TODO: udpListener does not work now.
-func udpListener(network, addr string) (l Listener, err error) {
-	ln := &listener{}
-	ln.pconn, err = net.ListenPacket(network, addr)
-	if err != nil {
-		return nil, err
-	}
-	ln.addr = ln.pconn.LocalAddr()
-	switch pconn := ln.pconn.(type) {
-	case *net.UDPConn:
-		ln.file, err = pconn.File()
-	}
-	if err != nil {
-		return nil, err
-	}
-	ln.fd = int(ln.file.Fd())
-	return ln, syscall.SetNonblock(ln.fd, true)
-}
-
 var _ net.Listener = &listener{}
 
 type listener struct {
-	fd    int
-	addr  net.Addr       // listener's local addr
-	ln    net.Listener   // tcp|unix listener
-	pconn net.PacketConn // udp listener
-	file  *os.File
+	fd   int
+	addr net.Addr     // listener's local addr
+	ln   net.Listener // tcp|unix listener
+	file *os.File
 }
 
 // Accept implements Listener.
 func (ln *listener) Accept() (net.Conn, error) {
-	// udp
-	if ln.pconn != nil {
-		return ln.UDPAccept()
-	}
-	// tcp
 	fd, sa, err := syscall.Accept(ln.fd)
 	if err != nil {
 		/* https://man7.org/linux/man-pages/man2/accept.2.html
@@ -112,11 +86,6 @@ func (ln *listener) Accept() (net.Conn, error) {
 	return nfd, nil
 }
 
-// TODO: UDPAccept Not implemented.
-func (ln *listener) UDPAccept() (net.Conn, error) {
-	return nil, Exception(ErrUnsupported, "UDP")
-}
-
 // Close implements Listener.
 func (ln *listener) Close() error {
 	if ln.fd != 0 {
@@ -128,9 +97,6 @@ func (ln *listener) Close() error {
 	if ln.ln != nil {
 		ln.ln.Close()
 	}
-	if ln.pconn != nil {
-		ln.pconn.Close()
-	}
 	return nil
 }
 

net_netfd.go

@@ -33,16 +33,15 @@ type netFD struct {
 	pd *pollDesc
 	// closed marks whether fd has expired
 	closed uint32
-	// Whether this is a streaming descriptor, as opposed to a
-	// packet-based descriptor like a UDP socket. Immutable.
+	// Whether this is a streaming descriptor. Immutable.
 	isStream bool
 	// Whether a zero byte read indicates EOF. This is false for a
 	// message based socket connection.
 	zeroReadIsEOF bool
 	family        int    // AF_INET, AF_INET6, syscall.AF_UNIX
 	sotype        int    // syscall.SOCK_STREAM, syscall.SOCK_DGRAM, syscall.SOCK_RAW
 	isConnected   bool   // handshake completed or use of association with peer
-	network       string // tcp tcp4 tcp6, udp, udp4, udp6, ip, ip4, ip6, unix, unixgram, unixpacket
+	network       string // tcp, tcp4, tcp6, unix, unixgram, unixpacket
 	localAddr     net.Addr
 	remoteAddr    net.Addr
 	// for detaching conn from poller

net_sock.go

@@ -17,7 +17,7 @@ import (
 	"syscall"
 )
 
-// A sockaddr represents a TCP, UDP, IP or Unix network endpoint
+// A sockaddr represents a TCP, IP or Unix network endpoint
 // address that can be converted into a syscall.Sockaddr.
 type sockaddr interface {
 	net.Addr
@@ -55,8 +55,8 @@ func internetSocket(ctx context.Context, net string, laddr, raddr sockaddr, soty
 // address family, both AF_INET and AF_INET6, and a wildcard address
 // like the following:
 //
-//   - A listen for a wildcard communication domain, "tcp" or
-//     "udp", with a wildcard address: If the platform supports
+//   - A listen for a wildcard communication domain, "tcp",
+//     with a wildcard address: If the platform supports
 //     both IPv6 and IPv4-mapped IPv6 communication capabilities,
 //     or does not support IPv4, we use a dual stack, AF_INET6 and
 //     IPV6_V6ONLY=0, wildcard address listen. The dual stack
@@ -65,17 +65,17 @@ func internetSocket(ctx context.Context, net string, laddr, raddr sockaddr, soty
 //     Otherwise we prefer an IPv4-only, AF_INET, wildcard address
 //     listen.
 //
-//   - A listen for a wildcard communication domain, "tcp" or
-//     "udp", with an IPv4 wildcard address: same as above.
+//   - A listen for a wildcard communication domain, "tcp",
+//     with an IPv4 wildcard address: same as above.
 //
-//   - A listen for a wildcard communication domain, "tcp" or
-//     "udp", with an IPv6 wildcard address: same as above.
+//   - A listen for a wildcard communication domain, "tcp",
+//     with an IPv6 wildcard address: same as above.
 //
-//   - A listen for an IPv4 communication domain, "tcp4" or "udp4",
+//   - A listen for an IPv4 communication domain, "tcp4",
 //     with an IPv4 wildcard address: We use an IPv4-only, AF_INET,
 //     wildcard address listen.
 //
-//   - A listen for an IPv6 communication domain, "tcp6" or "udp6",
+//   - A listen for an IPv6 communication domain, "tcp6",
 //     with an IPv6 wildcard address: We use an IPv6-only, AF_INET6
 //     and IPV6_V6ONLY=1, wildcard address listen.
 //