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http.go
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http.go
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package main
import (
"bytes"
"errors"
"fmt"
"github.com/cyfdecyf/bufio"
"io"
"net"
"strconv"
"strings"
"time"
)
type Header struct {
ContLen int64
KeepAlive time.Duration
ProxyAuthorization string
Chunking bool
ConnectionKeepAlive bool
}
type rqState byte
const (
rsCreated rqState = iota
rsSent // request has been sent to server
rsRecvBody // response header received, receiving response body
rsDone
)
type Request struct {
Method string
URL *URL
raw *bytes.Buffer // stores the raw content of request header
rawByte []byte // underlying buffer for raw
// request line from client starts at 0, cow generates request line that
// can be sent directly to web server
reqLnStart int // start of generated request line in raw
headStart int // start of header in raw
bodyStart int // start of body in raw
Header
isConnect bool
partial bool // whether contains only partial request data
state rqState
tryCnt byte
}
var zeroRequest = Request{}
func (r *Request) reset() {
b := r.rawByte
raw := r.raw
*r = zeroRequest // reset to zero value
if raw != nil {
raw.Reset()
r.rawByte = b
r.raw = raw
} else {
r.rawByte = httpBuf.Get()
r.raw = bytes.NewBuffer(r.rawByte[:0]) // must use 0 length slice
}
}
func (r *Request) String() (s string) {
return fmt.Sprintf("%s %s%s", r.Method, r.URL.HostPort, r.URL.Path)
}
func (r *Request) Verbose() []byte {
var rqbyte []byte
if r.isConnect {
rqbyte = r.rawBeforeBody()
} else {
// This includes client request line if has http parent proxy
rqbyte = r.raw.Bytes()
}
return rqbyte
}
func (r *Request) isRetry() bool {
return r.tryCnt > 1
}
func (r *Request) tryOnce() {
r.tryCnt++
}
func (r *Request) tooManyRetry() bool {
return r.tryCnt > 3
}
func (r *Request) responseNotSent() bool {
return r.state <= rsSent
}
func (r *Request) releaseBuf() {
if r.raw != nil {
httpBuf.Put(r.rawByte)
r.rawByte = nil
r.raw = nil
}
}
// rawRequest returns the raw request that can be sent directly to HTTP/1.1 server.
func (r *Request) rawRequest() []byte {
return r.raw.Bytes()[r.reqLnStart:]
}
func (r *Request) rawBeforeBody() []byte {
return r.raw.Bytes()[:r.bodyStart]
}
func (r *Request) rawHeaderBody() []byte {
return r.raw.Bytes()[r.headStart:]
}
func (r *Request) rawBody() []byte {
return r.raw.Bytes()[r.bodyStart:]
}
func (r *Request) proxyRequestLine() []byte {
return r.raw.Bytes()[0:r.reqLnStart]
}
type Response struct {
Status int
Reason []byte
Header
raw *bytes.Buffer
rawByte []byte
}
var zeroResponse = Response{}
func (rp *Response) reset() {
b := rp.rawByte
raw := rp.raw
*rp = zeroResponse
if raw != nil {
raw.Reset()
rp.rawByte = b
rp.raw = raw
} else {
rp.rawByte = httpBuf.Get()
rp.raw = bytes.NewBuffer(rp.rawByte[:0])
}
}
func (rp *Response) releaseBuf() {
if rp.raw != nil {
httpBuf.Put(rp.rawByte)
rp.rawByte = nil
rp.raw = nil
}
}
func (rp *Response) rawResponse() []byte {
return rp.raw.Bytes()
}
func (rp *Response) genStatusLine() (res string) {
if len(rp.Reason) == 0 {
res = strings.Join([]string{"HTTP/1.1", strconv.Itoa(rp.Status)}, " ")
} else {
res = strings.Join([]string{"HTTP/1.1", strconv.Itoa(rp.Status), string(rp.Reason)}, " ")
}
res += CRLF
return
}
func (rp *Response) String() string {
return fmt.Sprintf("%d %s", rp.Status, rp.Reason)
}
func (rp *Response) Verbose() []byte {
return rp.raw.Bytes()
}
type URL struct {
HostPort string // must contain port
Host string // no port
Port string
Domain string
Path string
}
func (url *URL) String() string {
return url.HostPort + url.Path
}
func (url *URL) HostIsIP() bool {
return hostIsIP(url.Host)
}
// For port, return empty string if no port specified.
// This also works for IPv6 address.
func splitHostPort(s string) (host, port string) {
if len(s) == 0 {
return "", ""
}
// Common case should has no port, check the last char first
if !IsDigit(s[len(s)-1]) {
return s, ""
}
// Scan back, make sure we find ':'
for i := len(s) - 2; i >= 0; i-- {
c := s[i]
switch {
case c == ':':
return s[:i], s[i+1:]
case !IsDigit(c):
return s, ""
}
}
return s, ""
}
// net.ParseRequestURI will unescape encoded path, but the proxy doesn't need
// that. Assumes the input rawurl is valid. Even if rawurl is not valid, net.Dial
// will check the correctness of the host.
func ParseRequestURI(rawurl string) (*URL, error) {
return ParseRequestURIBytes([]byte(rawurl))
}
func ParseRequestURIBytes(rawurl []byte) (*URL, error) {
if rawurl[0] == '/' {
return &URL{Path: string(rawurl)}, nil
}
var f [][]byte
var rest, scheme []byte
f = bytes.SplitN(rawurl, []byte("://"), 2)
if len(f) == 1 {
rest = f[0]
scheme = []byte("http") // default to http
} else {
ASCIIToLowerInplace(f[0]) // it's ok to lower case scheme
scheme = f[0]
if !bytes.Equal(scheme, []byte("http")) && !bytes.Equal(scheme, []byte("https")) {
errl.Printf("%s protocol not supported\n", scheme)
return nil, errors.New("protocol not supported")
}
rest = f[1]
}
var hostport, host, port, path string
id := bytes.IndexByte(rest, '/')
if id == -1 {
hostport = string(rest)
} else {
hostport = string(rest[:id])
path = string(rest[id:])
}
// Must add port in host so it can be used as key to find the correct
// server connection.
// e.g. google.com:80 and google.com:443 should use different connections.
host, port = splitHostPort(hostport)
if port == "" {
if len(scheme) == 4 {
hostport = net.JoinHostPort(host, "80")
port = "80"
} else {
hostport = net.JoinHostPort(host, "443")
port = "443"
}
}
return &URL{hostport, host, port, host2Domain(host), path}, nil
}
// headers of interest to a proxy
// Define them as constant and use editor's completion to avoid typos.
// Note RFC2616 only says about "Connection", no "Proxy-Connection", but firefox
// send this header.
// See more at http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/web-proxy-connection-header.html
const (
headerConnection = "connection"
headerContentLength = "content-length"
headerKeepAlive = "keep-alive"
headerProxyAuthenticate = "proxy-authenticate"
headerProxyAuthorization = "proxy-authorization"
headerProxyConnection = "proxy-connection"
headerReferer = "referer"
headerTE = "te"
headerTrailer = "trailer"
headerTransferEncoding = "transfer-encoding"
headerUpgrade = "upgrade"
fullHeaderConnection = "Connection: keep-alive\r\n"
fullHeaderTransferEncoding = "Transfer-Encoding: chunked\r\n"
)
// Using Go's method expression
var headerParser = map[string]HeaderParserFunc{
headerConnection: (*Header).parseConnection,
headerContentLength: (*Header).parseContentLength,
headerKeepAlive: (*Header).parseKeepAlive,
headerProxyAuthorization: (*Header).parseProxyAuthorization,
headerProxyConnection: (*Header).parseConnection,
headerTransferEncoding: (*Header).parseTransferEncoding,
}
var hopByHopHeader = map[string]bool{
headerConnection: true,
headerKeepAlive: true,
headerProxyAuthorization: true,
headerProxyConnection: true,
headerTE: true,
headerTrailer: true,
headerTransferEncoding: true,
headerUpgrade: true,
}
type HeaderParserFunc func(*Header, []byte, *bytes.Buffer) error
func (h *Header) parseConnection(s []byte, raw *bytes.Buffer) error {
h.ConnectionKeepAlive = bytes.Contains(s, []byte("keep-alive"))
raw.WriteString(fullHeaderConnection)
return nil
}
func (h *Header) parseContentLength(s []byte, raw *bytes.Buffer) (err error) {
h.ContLen, err = ParseIntFromBytes(s, 10)
return err
}
func (h *Header) parseKeepAlive(s []byte, raw *bytes.Buffer) (err error) {
id := bytes.Index(s, []byte("timeout="))
if id != -1 {
id += len("timeout=")
end := id
for ; end < len(s) && IsDigit(s[end]); end++ {
}
delta, _ := ParseIntFromBytes(s[id:end], 10)
h.KeepAlive = time.Second * time.Duration(delta)
}
return nil
}
func (h *Header) parseProxyAuthorization(s []byte, raw *bytes.Buffer) error {
h.ProxyAuthorization = string(s)
return nil
}
func (h *Header) parseTransferEncoding(s []byte, raw *bytes.Buffer) error {
// For transfer-encoding: identify, it's the same as specifying neither
// content-length nor transfer-encoding.
h.Chunking = bytes.Contains(s, []byte("chunked"))
if h.Chunking {
raw.WriteString(fullHeaderTransferEncoding)
} else if !bytes.Contains(s, []byte("identity")) {
errl.Printf("invalid transfer encoding: %s\n", s)
return errNotSupported
}
return nil
}
func splitHeader(s []byte) (name, val []byte, err error) {
var f [][]byte
if f = bytes.SplitN(s, []byte{':'}, 2); len(f) != 2 {
errl.Printf("malformed header: %s\n", s)
return nil, nil, errMalformHeader
}
// Do not lower case field value, as it maybe case sensitive
return ASCIIToLower(f[0]), f[1], nil
}
// Only add headers that are of interest for a proxy into request/response's header map.
func (h *Header) parseHeader(reader *bufio.Reader, raw *bytes.Buffer, url *URL) (err error) {
h.ContLen = -1
dummyLastLine := []byte{}
// Read request header and body
var s, name, val, lastLine []byte
for {
if s, err = reader.ReadSlice('\n'); err != nil {
return
}
// There are servers that use \n for line ending, so trim first before check ending.
// For example, the 404 page for http://plan9.bell-labs.com/magic/man2html/1/2l
trimmed := TrimSpace(s)
if len(trimmed) == 0 { // end of headers
return
}
if (s[0] == ' ' || s[0] == '\t') && lastLine != nil { // multi-line header
// I've never seen multi-line header used in headers that's of interest.
// Disable multi-line support to avoid copy for now.
errl.Printf("Multi-line support disabled: %v %s", url, s)
return errNotSupported
// combine previous line with current line
// trimmed = bytes.Join([][]byte{lastLine, []byte{' '}, trimmed}, nil)
}
if name, val, err = splitHeader(trimmed); err != nil {
return
}
// Wait Go to solve/provide the string<->[]byte optimization
kn := string(name)
if parseFunc, ok := headerParser[kn]; ok {
// lastLine = append([]byte(nil), trimmed...) // copy to avoid next read invalidating the trimmed line
lastLine = dummyLastLine
val = TrimSpace(val)
if len(val) == 0 {
continue
}
parseFunc(h, ASCIIToLower(val), raw)
} else {
// mark this header as not of interest to proxy
lastLine = nil
}
if hopByHopHeader[kn] {
continue
}
raw.Write(s)
// debug.Printf("len %d %s", len(s), s)
}
return
}
// Parse the request line and header, does not touch body
func parseRequest(c *clientConn, r *Request) (err error) {
var s []byte
reader := c.bufRd
setConnReadTimeout(c, clientConnTimeout, "parseRequest")
// parse request line
if s, err = reader.ReadSlice('\n'); err != nil {
return err
}
unsetConnReadTimeout(c, "parseRequest")
// debug.Printf("Request line %s", s)
r.reset()
// for http parent proxy, store the original request line
if config.hasHttpParent {
r.raw.Write(s)
r.reqLnStart = len(s)
}
var f [][]byte
// Tolerate with multiple spaces and '\t' is achieved by FieldsN.
if f = FieldsN(s, 3); len(f) != 3 {
return errors.New(fmt.Sprintf("malformed HTTP request: %s", s))
}
ASCIIToUpperInplace(f[0])
r.Method = string(f[0])
// Parse URI into host and path
r.URL, err = ParseRequestURIBytes(f[1])
if err != nil {
return
}
if r.Method == "CONNECT" {
r.isConnect = true
if bool(dbgRq) && verbose && !config.hasHttpParent {
r.raw.Write(s)
}
} else {
// Generate normal HTTP request line
r.raw.WriteString(r.Method + " ")
if len(r.URL.Path) == 0 {
r.raw.WriteString("/")
} else {
r.raw.WriteString(r.URL.Path)
}
r.raw.WriteString(" HTTP/1.1\r\n")
}
r.headStart = r.raw.Len()
// Read request header
if err = r.parseHeader(reader, r.raw, r.URL); err != nil {
errl.Printf("Parsing request header: %v\n", err)
return err
}
if !r.ConnectionKeepAlive {
// Always add one connection header for request
r.raw.WriteString(fullHeaderConnection)
}
// The spec says proxy must add Via header. polipo disables this by
// default, and I don't want to let others know the user is using COW, so
// don't add it.
r.raw.WriteString(CRLF)
r.bodyStart = r.raw.Len()
return
}
func skipCRLF(r *bufio.Reader) error {
// There maybe servers using single '\n' for line ending
if _, err := r.ReadSlice('\n'); err != nil {
errl.Println("Error reading CRLF:", err)
return err
}
return nil
}
// If an http response may have message body
func (rp *Response) hasBody(method string) bool {
if method == "HEAD" || rp.Status == 304 || rp.Status == 204 ||
(100 <= rp.Status && rp.Status < 200) {
return false
}
return true
}
// Parse response status and headers.
func parseResponse(sv *serverConn, r *Request, rp *Response) (err error) {
var s []byte
reader := sv.bufRd
if sv.maybeFake() {
sv.setReadTimeout("parseResponse")
}
if s, err = reader.ReadSlice('\n'); err != nil {
if err != io.EOF {
// err maybe timeout caused by explicity setting deadline
debug.Printf("Reading Response status line: %v %v\n", err, r)
}
// For timeout, the connection will not be used, so no need to unset timeout
return err
}
if sv.maybeFake() {
sv.unsetReadTimeout("parseResponse")
}
// debug.Printf("Response line %s", s)
// response status line parsing
var f [][]byte
if f = FieldsN(s, 3); len(f) < 2 { // status line are separated by SP
errl.Printf("Malformed HTTP response status line: %s %v\n", s, r)
return errMalformResponse
}
status, err := ParseIntFromBytes(f[1], 10)
rp.reset()
rp.Status = int(status)
if err != nil {
errl.Printf("response status not valid: %s len=%d %v\n", f[1], len(f[1]), err)
return
}
if len(f) == 3 {
rp.Reason = f[2]
}
proto := f[0]
if !bytes.Equal(proto[0:7], []byte("HTTP/1.")) {
errl.Printf("Invalid response status line: %s\n", string(f[0]))
return errMalformResponse
}
if proto[7] == '1' {
rp.raw.Write(s)
} else if proto[7] == '0' {
// Should return HTTP version as 1.1 to client since closed connection
// will be converted to chunked encoding
rp.raw.WriteString(rp.genStatusLine())
} else {
errl.Printf("Response protocol not supported: %s\n", f[0])
return errNotSupported
}
if err = rp.parseHeader(reader, rp.raw, r.URL); err != nil {
errl.Printf("Reading response header: %v %v\n", err, r)
return err
}
// Connection close, no content length specification
// Use chunked encoding to pass content back to client
if !rp.ConnectionKeepAlive && !rp.Chunking && rp.ContLen == -1 {
rp.raw.WriteString("Transfer-Encoding: chunked\r\n")
}
if !rp.ConnectionKeepAlive {
rp.raw.WriteString("Connection: keep-alive\r\n")
}
rp.raw.WriteString(keepAliveHeader)
rp.raw.WriteString(CRLF)
return nil
}
func unquote(s string) string {
return strings.Trim(s, "\"")
}
func parseKeyValueList(str string) map[string]string {
list := strings.Split(str, ",")
if len(list) == 1 && list[0] == "" {
return nil
}
res := make(map[string]string)
for _, ele := range list {
kv := strings.SplitN(strings.TrimSpace(ele), "=", 2)
if len(kv) != 2 {
errl.Println("no equal sign in key value list element:", ele)
return nil
}
key, val := kv[0], unquote(kv[1])
res[key] = val
}
return res
}