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sniff.go
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/
sniff.go
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package http
import (
"bytes"
"errors"
"strings"
"v2ray.com/core/common"
"v2ray.com/core/common/net"
)
type version byte
const (
HTTP1 version = iota
HTTP2
)
type SniffHeader struct {
version version
host string
}
func (h *SniffHeader) Protocol() string {
switch h.version {
case HTTP1:
return "http1"
case HTTP2:
return "http2"
default:
return "unknown"
}
}
func (h *SniffHeader) Domain() string {
return h.host
}
var (
methods = [...]string{"get", "post", "head", "put", "delete", "options", "connect"}
errNotHTTPMethod = errors.New("not an HTTP method")
)
func beginWithHTTPMethod(b []byte) error {
for _, m := range &methods {
if len(b) >= len(m) && strings.ToLower(string(b[:len(m)])) == m {
return nil
}
if len(b) < len(m) {
return common.ErrNoClue
}
}
return errNotHTTPMethod
}
func SniffHTTP(b []byte) (*SniffHeader, error) {
if err := beginWithHTTPMethod(b); err != nil {
return nil, err
}
sh := &SniffHeader{
version: HTTP1,
}
headers := bytes.Split(b, []byte{'\n'})
for i := 1; i < len(headers); i++ {
header := headers[i]
if len(header) == 0 {
break
}
parts := bytes.SplitN(header, []byte{':'}, 2)
if len(parts) != 2 {
continue
}
key := strings.ToLower(string(parts[0]))
if key == "host" {
rawHost := strings.ToLower(string(bytes.TrimSpace(parts[1])))
dest, err := ParseHost(rawHost, net.Port(80))
if err != nil {
return nil, err
}
sh.host = dest.Address.String()
}
}
if len(sh.host) > 0 {
return sh, nil
}
return nil, common.ErrNoClue
}