464 lines
11 KiB
Go
464 lines
11 KiB
Go
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package http2 implements the HTTP/2 protocol.
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//
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// This package is low-level and intended to be used directly by very
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// few people. Most users will use it indirectly through the automatic
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// use by the net/http package (from Go 1.6 and later).
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// For use in earlier Go versions see ConfigureServer. (Transport support
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// requires Go 1.6 or later)
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//
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// See https://http2.github.io/ for more information on HTTP/2.
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//
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// See https://http2.golang.org/ for a test server running this code.
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package http2
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import (
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"bufio"
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"crypto/tls"
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"errors"
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"fmt"
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"io"
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"net/http"
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"os"
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"sort"
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"strconv"
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"strings"
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"sync"
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)
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var (
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VerboseLogs bool
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logFrameWrites bool
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logFrameReads bool
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)
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func init() {
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e := os.Getenv("GODEBUG")
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if strings.Contains(e, "http2debug=1") {
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VerboseLogs = true
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}
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if strings.Contains(e, "http2debug=2") {
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VerboseLogs = true
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logFrameWrites = true
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logFrameReads = true
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}
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}
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const (
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// ClientPreface is the string that must be sent by new
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// connections from clients.
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ClientPreface = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
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// SETTINGS_MAX_FRAME_SIZE default
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// http://http2.github.io/http2-spec/#rfc.section.6.5.2
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initialMaxFrameSize = 16384
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// NextProtoTLS is the NPN/ALPN protocol negotiated during
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// HTTP/2's TLS setup.
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NextProtoTLS = "h2"
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// http://http2.github.io/http2-spec/#SettingValues
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initialHeaderTableSize = 4096
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initialWindowSize = 65535 // 6.9.2 Initial Flow Control Window Size
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defaultMaxReadFrameSize = 1 << 20
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)
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var (
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clientPreface = []byte(ClientPreface)
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)
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type streamState int
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const (
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stateIdle streamState = iota
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stateOpen
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stateHalfClosedLocal
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stateHalfClosedRemote
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stateResvLocal
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stateResvRemote
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stateClosed
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)
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var stateName = [...]string{
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stateIdle: "Idle",
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stateOpen: "Open",
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stateHalfClosedLocal: "HalfClosedLocal",
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stateHalfClosedRemote: "HalfClosedRemote",
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stateResvLocal: "ResvLocal",
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stateResvRemote: "ResvRemote",
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stateClosed: "Closed",
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}
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func (st streamState) String() string {
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return stateName[st]
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}
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// Setting is a setting parameter: which setting it is, and its value.
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type Setting struct {
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// ID is which setting is being set.
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// See http://http2.github.io/http2-spec/#SettingValues
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ID SettingID
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// Val is the value.
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Val uint32
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}
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func (s Setting) String() string {
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return fmt.Sprintf("[%v = %d]", s.ID, s.Val)
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}
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// Valid reports whether the setting is valid.
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func (s Setting) Valid() error {
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// Limits and error codes from 6.5.2 Defined SETTINGS Parameters
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switch s.ID {
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case SettingEnablePush:
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if s.Val != 1 && s.Val != 0 {
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return ConnectionError(ErrCodeProtocol)
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}
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case SettingInitialWindowSize:
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if s.Val > 1<<31-1 {
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return ConnectionError(ErrCodeFlowControl)
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}
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case SettingMaxFrameSize:
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if s.Val < 16384 || s.Val > 1<<24-1 {
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return ConnectionError(ErrCodeProtocol)
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}
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}
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return nil
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}
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// A SettingID is an HTTP/2 setting as defined in
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// http://http2.github.io/http2-spec/#iana-settings
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type SettingID uint16
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const (
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SettingHeaderTableSize SettingID = 0x1
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SettingEnablePush SettingID = 0x2
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SettingMaxConcurrentStreams SettingID = 0x3
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SettingInitialWindowSize SettingID = 0x4
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SettingMaxFrameSize SettingID = 0x5
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SettingMaxHeaderListSize SettingID = 0x6
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)
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var settingName = map[SettingID]string{
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SettingHeaderTableSize: "HEADER_TABLE_SIZE",
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SettingEnablePush: "ENABLE_PUSH",
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SettingMaxConcurrentStreams: "MAX_CONCURRENT_STREAMS",
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SettingInitialWindowSize: "INITIAL_WINDOW_SIZE",
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SettingMaxFrameSize: "MAX_FRAME_SIZE",
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SettingMaxHeaderListSize: "MAX_HEADER_LIST_SIZE",
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}
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func (s SettingID) String() string {
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if v, ok := settingName[s]; ok {
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return v
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}
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return fmt.Sprintf("UNKNOWN_SETTING_%d", uint16(s))
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}
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var (
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errInvalidHeaderFieldName = errors.New("http2: invalid header field name")
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errInvalidHeaderFieldValue = errors.New("http2: invalid header field value")
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)
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// validHeaderFieldName reports whether v is a valid header field name (key).
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// RFC 7230 says:
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// header-field = field-name ":" OWS field-value OWS
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// field-name = token
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// tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
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// "^" / "_" / "
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// Further, http2 says:
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// "Just as in HTTP/1.x, header field names are strings of ASCII
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// characters that are compared in a case-insensitive
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// fashion. However, header field names MUST be converted to
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// lowercase prior to their encoding in HTTP/2. "
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func validHeaderFieldName(v string) bool {
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if len(v) == 0 {
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return false
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}
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for _, r := range v {
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if int(r) >= len(isTokenTable) || ('A' <= r && r <= 'Z') {
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return false
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}
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if !isTokenTable[byte(r)] {
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return false
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}
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}
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return true
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}
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// validHeaderFieldValue reports whether v is a valid header field value.
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//
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// RFC 7230 says:
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// field-value = *( field-content / obs-fold )
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// obj-fold = N/A to http2, and deprecated
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// field-content = field-vchar [ 1*( SP / HTAB ) field-vchar ]
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// field-vchar = VCHAR / obs-text
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// obs-text = %x80-FF
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// VCHAR = "any visible [USASCII] character"
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//
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// http2 further says: "Similarly, HTTP/2 allows header field values
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// that are not valid. While most of the values that can be encoded
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// will not alter header field parsing, carriage return (CR, ASCII
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// 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII
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// 0x0) might be exploited by an attacker if they are translated
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// verbatim. Any request or response that contains a character not
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// permitted in a header field value MUST be treated as malformed
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// (Section 8.1.2.6). Valid characters are defined by the
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// field-content ABNF rule in Section 3.2 of [RFC7230]."
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//
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// This function does not (yet?) properly handle the rejection of
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// strings that begin or end with SP or HTAB.
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func validHeaderFieldValue(v string) bool {
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for i := 0; i < len(v); i++ {
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if b := v[i]; b < ' ' && b != '\t' || b == 0x7f {
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return false
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}
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}
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return true
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}
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var httpCodeStringCommon = map[int]string{} // n -> strconv.Itoa(n)
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func init() {
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for i := 100; i <= 999; i++ {
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if v := http.StatusText(i); v != "" {
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httpCodeStringCommon[i] = strconv.Itoa(i)
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}
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}
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}
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func httpCodeString(code int) string {
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if s, ok := httpCodeStringCommon[code]; ok {
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return s
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}
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return strconv.Itoa(code)
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}
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// from pkg io
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type stringWriter interface {
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WriteString(s string) (n int, err error)
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}
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// A gate lets two goroutines coordinate their activities.
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type gate chan struct{}
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func (g gate) Done() { g <- struct{}{} }
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func (g gate) Wait() { <-g }
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// A closeWaiter is like a sync.WaitGroup but only goes 1 to 0 (open to closed).
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type closeWaiter chan struct{}
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// Init makes a closeWaiter usable.
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// It exists because so a closeWaiter value can be placed inside a
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// larger struct and have the Mutex and Cond's memory in the same
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// allocation.
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func (cw *closeWaiter) Init() {
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*cw = make(chan struct{})
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}
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// Close marks the closeWaiter as closed and unblocks any waiters.
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func (cw closeWaiter) Close() {
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close(cw)
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}
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// Wait waits for the closeWaiter to become closed.
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func (cw closeWaiter) Wait() {
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<-cw
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}
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// bufferedWriter is a buffered writer that writes to w.
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// Its buffered writer is lazily allocated as needed, to minimize
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// idle memory usage with many connections.
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type bufferedWriter struct {
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w io.Writer // immutable
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bw *bufio.Writer // non-nil when data is buffered
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}
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func newBufferedWriter(w io.Writer) *bufferedWriter {
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return &bufferedWriter{w: w}
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}
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var bufWriterPool = sync.Pool{
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New: func() interface{} {
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// TODO: pick something better? this is a bit under
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// (3 x typical 1500 byte MTU) at least.
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return bufio.NewWriterSize(nil, 4<<10)
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},
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}
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func (w *bufferedWriter) Write(p []byte) (n int, err error) {
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if w.bw == nil {
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bw := bufWriterPool.Get().(*bufio.Writer)
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bw.Reset(w.w)
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w.bw = bw
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}
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return w.bw.Write(p)
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}
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func (w *bufferedWriter) Flush() error {
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bw := w.bw
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if bw == nil {
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return nil
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}
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err := bw.Flush()
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bw.Reset(nil)
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bufWriterPool.Put(bw)
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w.bw = nil
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return err
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}
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func mustUint31(v int32) uint32 {
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if v < 0 || v > 2147483647 {
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panic("out of range")
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}
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return uint32(v)
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}
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// bodyAllowedForStatus reports whether a given response status code
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// permits a body. See RFC2616, section 4.4.
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func bodyAllowedForStatus(status int) bool {
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switch {
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case status >= 100 && status <= 199:
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return false
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case status == 204:
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return false
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case status == 304:
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return false
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}
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return true
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}
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type httpError struct {
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msg string
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timeout bool
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}
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func (e *httpError) Error() string { return e.msg }
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func (e *httpError) Timeout() bool { return e.timeout }
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func (e *httpError) Temporary() bool { return true }
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var errTimeout error = &httpError{msg: "http2: timeout awaiting response headers", timeout: true}
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var isTokenTable = [127]bool{
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'!': true,
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'#': true,
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'$': true,
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'%': true,
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'&': true,
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'\'': true,
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'*': true,
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'+': true,
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'-': true,
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'.': true,
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'0': true,
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'1': true,
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'2': true,
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'3': true,
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'4': true,
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'5': true,
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'6': true,
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'7': true,
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'8': true,
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'9': true,
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'A': true,
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'B': true,
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'C': true,
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'D': true,
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'E': true,
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'F': true,
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'G': true,
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'H': true,
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'I': true,
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'J': true,
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'K': true,
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'L': true,
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'M': true,
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'N': true,
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'O': true,
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'P': true,
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'Q': true,
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'R': true,
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'S': true,
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'T': true,
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'U': true,
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'W': true,
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'V': true,
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'X': true,
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'Y': true,
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'Z': true,
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'^': true,
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'_': true,
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'`': true,
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|
|
'a': true,
|
||
|
|
'b': true,
|
||
|
|
'c': true,
|
||
|
|
'd': true,
|
||
|
|
'e': true,
|
||
|
|
'f': true,
|
||
|
|
'g': true,
|
||
|
|
'h': true,
|
||
|
|
'i': true,
|
||
|
|
'j': true,
|
||
|
|
'k': true,
|
||
|
|
'l': true,
|
||
|
|
'm': true,
|
||
|
|
'n': true,
|
||
|
|
'o': true,
|
||
|
|
'p': true,
|
||
|
|
'q': true,
|
||
|
|
'r': true,
|
||
|
|
's': true,
|
||
|
|
't': true,
|
||
|
|
'u': true,
|
||
|
|
'v': true,
|
||
|
|
'w': true,
|
||
|
|
'x': true,
|
||
|
|
'y': true,
|
||
|
|
'z': true,
|
||
|
|
'|': true,
|
||
|
|
'~': true,
|
||
|
|
}
|
||
|
|
|
||
|
|
type connectionStater interface {
|
||
|
|
ConnectionState() tls.ConnectionState
|
||
|
|
}
|
||
|
|
|
||
|
|
var sorterPool = sync.Pool{New: func() interface{} { return new(sorter) }}
|
||
|
|
|
||
|
|
type sorter struct {
|
||
|
|
v []string // owned by sorter
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *sorter) Len() int { return len(s.v) }
|
||
|
|
func (s *sorter) Swap(i, j int) { s.v[i], s.v[j] = s.v[j], s.v[i] }
|
||
|
|
func (s *sorter) Less(i, j int) bool { return s.v[i] < s.v[j] }
|
||
|
|
|
||
|
|
// Keys returns the sorted keys of h.
|
||
|
|
//
|
||
|
|
// The returned slice is only valid until s used again or returned to
|
||
|
|
// its pool.
|
||
|
|
func (s *sorter) Keys(h http.Header) []string {
|
||
|
|
keys := s.v[:0]
|
||
|
|
for k := range h {
|
||
|
|
keys = append(keys, k)
|
||
|
|
}
|
||
|
|
s.v = keys
|
||
|
|
sort.Sort(s)
|
||
|
|
return keys
|
||
|
|
}
|
||
|
|
|
||
|
|
func (s *sorter) SortStrings(ss []string) {
|
||
|
|
// Our sorter works on s.v, which sorter owners, so
|
||
|
|
// stash it away while we sort the user's buffer.
|
||
|
|
save := s.v
|
||
|
|
s.v = ss
|
||
|
|
sort.Sort(s)
|
||
|
|
s.v = save
|
||
|
|
}
|