net: add UDP listen, resolver, DNSError, and TCP listener APIs for wasm (#63)

* net: add UDP listen, resolver, DNSError, and TCP listener APIs for wasm

TinyGo's net package was missing several symbols that upstream Go's
js/wasm net declares, blocking builds that pull pion/transport, pion/dtls,
and similar (via netbird's WASM client). Add them, backed by the existing
netdev abstraction so they compile for all targets and no-op cleanly under
nopNetdev (matching Go's js runtime behavior):

- DNSError type (dnserror.go), copied from Go 1.26.2.
- Resolver + DefaultResolver with LookupHost/LookupIP/LookupIPAddr/
  LookupNetIP/LookupPort; LookupHost/LookupIP package funcs; Dialer.Resolver
  field for API compatibility.
- UDPConn: ListenUDP, ReadFromUDP(AddrPort), WriteToUDP(AddrPort),
  SetReadBuffer, SetWriteBuffer.
- TCPConn: CloseRead, SetNoDelay, SetReadBuffer, SetWriteBuffer,
  ReadFrom(io.Reader).
- TCPListener: ListenTCP, AcceptTCP, SetDeadline; ListenPacket package func.
- Interface: Addrs, MulticastAddrs stubs.

* more complete PR for adding more net support (#64)

* format unixsock

http/response.go

@@ -14,6 +14,7 @@ package http
 import (
 	"bufio"
 	"bytes"
+	"crypto/tls"
 	"errors"
 	"fmt"
 	"io"
@@ -117,6 +118,11 @@ type Response struct {
 	// Request's Body is nil (having already been consumed).
 	// This is only populated for Client requests.
 	Request *Request
+
+	// TLS contains information about the TLS connection on which the response
+	// was received. It is nil for unencrypted responses. TINYGO: populated only
+	// if a caller sets it; the wasm fetch path leaves it nil.
+	TLS *tls.ConnectionState
 }
 
 // Cookies parses and returns the cookies set in the Set-Cookie headers.

http/responsecontroller.go

@@ -0,0 +1,152 @@
+// TINYGO: Copied verbatim from the Go 1.26.2 official implementation to provide
+// the ResponseController API used by net/http/httputil (reverse proxy). The
+// underlying methods degrade to ErrNotSupported when the ResponseWriter does
+// not implement them, which is the standard behavior.
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"time"
+)
+
+// A ResponseController is used by an HTTP handler to control the response.
+//
+// A ResponseController may not be used after the [Handler.ServeHTTP] method has returned.
+type ResponseController struct {
+	rw ResponseWriter
+}
+
+// NewResponseController creates a [ResponseController] for a request.
+//
+// The ResponseWriter should be the original value passed to the [Handler.ServeHTTP] method,
+// or have an Unwrap method returning the original ResponseWriter.
+//
+// If the ResponseWriter implements any of the following methods, the ResponseController
+// will call them as appropriate:
+//
+//	Flush()
+//	FlushError() error // alternative Flush returning an error
+//	Hijack() (net.Conn, *bufio.ReadWriter, error)
+//	SetReadDeadline(deadline time.Time) error
+//	SetWriteDeadline(deadline time.Time) error
+//	EnableFullDuplex() error
+//
+// If the ResponseWriter does not support a method, ResponseController returns
+// an error matching [ErrNotSupported].
+func NewResponseController(rw ResponseWriter) *ResponseController {
+	return &ResponseController{rw}
+}
+
+type rwUnwrapper interface {
+	Unwrap() ResponseWriter
+}
+
+// Flush flushes buffered data to the client.
+func (c *ResponseController) Flush() error {
+	rw := c.rw
+	for {
+		switch t := rw.(type) {
+		case interface{ FlushError() error }:
+			return t.FlushError()
+		case Flusher:
+			t.Flush()
+			return nil
+		case rwUnwrapper:
+			rw = t.Unwrap()
+		default:
+			return errNotSupported()
+		}
+	}
+}
+
+// Hijack lets the caller take over the connection.
+// See the [Hijacker] interface for details.
+func (c *ResponseController) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	rw := c.rw
+	for {
+		switch t := rw.(type) {
+		case Hijacker:
+			return t.Hijack()
+		case rwUnwrapper:
+			rw = t.Unwrap()
+		default:
+			return nil, nil, errNotSupported()
+		}
+	}
+}
+
+// SetReadDeadline sets the deadline for reading the entire request, including the body.
+// Reads from the request body after the deadline has been exceeded will return an error.
+// A zero value means no deadline.
+//
+// Setting the read deadline after it has been exceeded will not extend it.
+func (c *ResponseController) SetReadDeadline(deadline time.Time) error {
+	rw := c.rw
+	for {
+		switch t := rw.(type) {
+		case interface{ SetReadDeadline(time.Time) error }:
+			return t.SetReadDeadline(deadline)
+		case rwUnwrapper:
+			rw = t.Unwrap()
+		default:
+			return errNotSupported()
+		}
+	}
+}
+
+// SetWriteDeadline sets the deadline for writing the response.
+// Writes to the response body after the deadline has been exceeded will not block,
+// but may succeed if the data has been buffered.
+// A zero value means no deadline.
+//
+// Setting the write deadline after it has been exceeded will not extend it.
+func (c *ResponseController) SetWriteDeadline(deadline time.Time) error {
+	rw := c.rw
+	for {
+		switch t := rw.(type) {
+		case interface{ SetWriteDeadline(time.Time) error }:
+			return t.SetWriteDeadline(deadline)
+		case rwUnwrapper:
+			rw = t.Unwrap()
+		default:
+			return errNotSupported()
+		}
+	}
+}
+
+// EnableFullDuplex indicates that the request handler will interleave reads from [Request.Body]
+// with writes to the [ResponseWriter].
+//
+// For HTTP/1 requests, the Go HTTP server by default consumes any unread portion of
+// the request body before beginning to write the response, preventing handlers from
+// concurrently reading from the request and writing the response.
+// Calling EnableFullDuplex disables this behavior and permits handlers to continue to read
+// from the request while concurrently writing the response.
+//
+// For HTTP/2 requests, the Go HTTP server always permits concurrent reads and responses.
+func (c *ResponseController) EnableFullDuplex() error {
+	rw := c.rw
+	for {
+		switch t := rw.(type) {
+		case interface{ EnableFullDuplex() error }:
+			return t.EnableFullDuplex()
+		case rwUnwrapper:
+			rw = t.Unwrap()
+		default:
+			return errNotSupported()
+		}
+	}
+}
+
+// errNotSupported returns an error that Is ErrNotSupported,
+// but is not == to it.
+func errNotSupported() error {
+	return fmt.Errorf("%w", ErrNotSupported)
+}

http/server.go

@@ -2779,6 +2779,23 @@ type Server struct {
 	// value.
 	ConnContext func(ctx context.Context, c net.Conn) context.Context
 
+	// TLSNextProto optionally specifies a function to take over
+	// ownership of the provided TLS connection when an ALPN
+	// protocol upgrade has occurred. The map key is the protocol
+	// name negotiated. The Handler argument should be used to
+	// handle HTTP requests and will initialize the Request's TLS
+	// and RemoteAddr if not already set. The connection is
+	// automatically closed when the function returns.
+	// If TLSNextProto is not nil, HTTP/2 support is not enabled
+	// automatically.
+	TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
+
+	// HTTP2 configures HTTP/2 connections.
+	//
+	// This field does not yet have any effect.
+	// See https://go.dev/issue/67813.
+	HTTP2 *HTTP2Config
+
 	inShutdown atomicBool // true when server is in shutdown
 
 	disableKeepAlives int32     // accessed atomically.

http/transport.go

@@ -12,8 +12,14 @@
 package http
 
 import (
+	"context"
+	"crypto/tls"
+	"errors"
 	"io"
+	"net"
+	"net/url"
 	"sync/atomic"
+	"time"
 )
 
 type readTrackingBody struct {
@@ -22,6 +28,106 @@ type readTrackingBody struct {
 	didClose atomic.Bool
 }
 
-type Transport struct{}
+// Transport is an HTTP/1.x RoundTripper. TINYGO: in the wasm/browser build the
+// actual round trips are performed by the host fetch API (see roundtrip_js.go);
+// these fields exist only to satisfy configuration by callers such as
+// golang.org/x/net/http2 and google.golang.org/grpc. They are stored but, aside
+// from fetch, have no effect at runtime.
+type Transport struct {
+	// TLSClientConfig specifies the TLS configuration to use with tls.Client.
+	TLSClientConfig *tls.Config
+
+	// TLSNextProto specifies how the Transport switches to an alternate
+	// protocol (such as HTTP/2) after a TLS ALPN protocol negotiation.
+	TLSNextProto map[string]func(authority string, c *tls.Conn) RoundTripper
+
+	// DisableKeepAlives, if true, disables HTTP keep-alives.
+	DisableKeepAlives bool
+
+	// DisableCompression, if true, prevents the Transport from requesting
+	// compression with an "Accept-Encoding: gzip" request header.
+	DisableCompression bool
+
+	// IdleConnTimeout is the maximum amount of time an idle connection will
+	// remain idle before closing itself. Zero means no limit.
+	IdleConnTimeout time.Duration
+
+	// ResponseHeaderTimeout, if non-zero, specifies the amount of time to wait
+	// for a server's response headers after fully writing the request.
+	ResponseHeaderTimeout time.Duration
+
+	// ExpectContinueTimeout, if non-zero, specifies the amount of time to wait
+	// for a server's first response headers after fully writing the request
+	// headers if the request has an "Expect: 100-continue" header.
+	ExpectContinueTimeout time.Duration
+
+	// MaxResponseHeaderBytes specifies a limit on how many response bytes are
+	// allowed in the server's response header. Zero means to use a default limit.
+	MaxResponseHeaderBytes int64
+
+	// MaxIdleConns controls the maximum number of idle (keep-alive) connections
+	// across all hosts. Zero means no limit.
+	MaxIdleConns int
+
+	// MaxIdleConnsPerHost, if non-zero, controls the maximum idle (keep-alive)
+	// connections to keep per-host.
+	MaxIdleConnsPerHost int
+
+	// MaxConnsPerHost optionally limits the total number of connections per host.
+	MaxConnsPerHost int
+
+	// HTTP2 configures HTTP/2 connections. This field does not yet have any effect.
+	HTTP2 *HTTP2Config
+
+	// Dial specifies the dial function for creating unencrypted TCP connections.
+	//
+	// Deprecated: Use DialContext instead. TINYGO: stored only; unused by the
+	// fetch-based round tripper.
+	Dial func(network, addr string) (net.Conn, error)
+
+	// DialContext specifies the dial function for creating unencrypted TCP
+	// connections. TINYGO: honored by callers that dial through the Transport
+	// directly (e.g. the relay WebSocket transport), which is how netbird routes
+	// connections through the netstack in the browser.
+	DialContext func(ctx context.Context, network, addr string) (net.Conn, error)
+}
 
 var DefaultTransport RoundTripper = &Transport{}
+
+// CloseIdleConnections closes any connections which were previously connected
+// from previous requests but are now sitting idle. TINYGO: no-op.
+func (t *Transport) CloseIdleConnections() {}
+
+// Clone returns a copy of t with its exported fields shared. TINYGO: the
+// tinygo Transport carries only configuration (round trips go through the host
+// fetch API), so a shallow struct copy with duplicated maps is sufficient.
+func (t *Transport) Clone() *Transport {
+	t2 := *t
+	if t.TLSClientConfig != nil {
+		t2.TLSClientConfig = t.TLSClientConfig.Clone()
+	}
+	if t.TLSNextProto != nil {
+		npm := make(map[string]func(authority string, c *tls.Conn) RoundTripper, len(t.TLSNextProto))
+		for k, v := range t.TLSNextProto {
+			npm[k] = v
+		}
+		t2.TLSNextProto = npm
+	}
+	return &t2
+}
+
+// ProxyFromEnvironment returns the URL of the proxy to use for a given request.
+// TINYGO: the wasm build has no environment proxy configuration, so this always
+// reports "no proxy" (nil URL, nil error), which callers treat as a direct
+// connection.
+func ProxyFromEnvironment(req *Request) (*url.URL, error) {
+	return nil, nil
+}
+
+// ErrSkipAltProtocol is a sentinel error value defined by Transport.RegisterProtocol.
+var ErrSkipAltProtocol = errors.New("net/http: skip alternate protocol")
+
+// RegisterProtocol registers a new protocol with scheme. TINYGO: no-op; the
+// wasm build performs round trips via the host fetch API and does not dispatch
+// on registered alternate protocols.
+func (t *Transport) RegisterProtocol(scheme string, rt RoundTripper) {}