mirror of https://github.com/caddyserver/caddy.git
103 lines
2.6 KiB
Go
103 lines
2.6 KiB
Go
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package caddyhttp
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import (
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"context"
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"crypto/tls"
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weakrand "math/rand"
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"net"
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"net/http"
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"sync/atomic"
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"time"
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"golang.org/x/net/http2"
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)
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// http2Listener wraps the listener to solve the following problems:
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// 1. server h2 natively without using h2c hack when listener handles tls connection but
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// don't return *tls.Conn
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// 2. graceful shutdown. the shutdown logic is copied from stdlib http.Server, it's an extra maintenance burden but
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// whatever, the shutdown logic maybe extracted to be used with h2c graceful shutdown. http2.Server supports graceful shutdown
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// sending GO_AWAY frame to connected clients, but doesn't track connection status. It requires explicit call of http2.ConfigureServer
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type http2Listener struct {
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cnt uint64
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net.Listener
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server *http.Server
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h2server *http2.Server
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}
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type connectionStateConn interface {
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net.Conn
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ConnectionState() tls.ConnectionState
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}
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func (h *http2Listener) Accept() (net.Conn, error) {
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for {
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conn, err := h.Listener.Accept()
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if err != nil {
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return nil, err
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}
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if csc, ok := conn.(connectionStateConn); ok {
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// *tls.Conn will return empty string because it's only populated after handshake is complete
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if csc.ConnectionState().NegotiatedProtocol == http2.NextProtoTLS {
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go h.serveHttp2(csc)
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continue
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}
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}
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return conn, nil
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}
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}
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func (h *http2Listener) serveHttp2(csc connectionStateConn) {
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atomic.AddUint64(&h.cnt, 1)
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h.runHook(csc, http.StateNew)
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defer func() {
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csc.Close()
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atomic.AddUint64(&h.cnt, ^uint64(0))
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h.runHook(csc, http.StateClosed)
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}()
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h.h2server.ServeConn(csc, &http2.ServeConnOpts{
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Context: h.server.ConnContext(context.Background(), csc),
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BaseConfig: h.server,
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Handler: h.server.Handler,
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})
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}
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const shutdownPollIntervalMax = 500 * time.Millisecond
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func (h *http2Listener) Shutdown(ctx context.Context) error {
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pollIntervalBase := time.Millisecond
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nextPollInterval := func() time.Duration {
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// Add 10% jitter.
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//nolint:gosec
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interval := pollIntervalBase + time.Duration(weakrand.Intn(int(pollIntervalBase/10)))
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// Double and clamp for next time.
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pollIntervalBase *= 2
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if pollIntervalBase > shutdownPollIntervalMax {
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pollIntervalBase = shutdownPollIntervalMax
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}
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return interval
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}
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timer := time.NewTimer(nextPollInterval())
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defer timer.Stop()
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for {
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if atomic.LoadUint64(&h.cnt) == 0 {
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return nil
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}
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select {
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case <-ctx.Done():
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return ctx.Err()
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case <-timer.C:
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timer.Reset(nextPollInterval())
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}
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}
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}
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func (h *http2Listener) runHook(conn net.Conn, state http.ConnState) {
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if h.server.ConnState != nil {
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h.server.ConnState(conn, state)
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}
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}
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