VLESS Encryption: Add customizable 1-RTT padding parameters; Decrease memory using; Chores

Completes https://github.com/XTLS/Xray-core/pull/5067

---------

Co-authored-by: wwqgtxx <wwqgtxx@gmail.com>

proxy/vless/encryption/common.go

@@ -7,10 +7,12 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/xtls/xray-core/common/crypto"
 	"github.com/xtls/xray-core/common/errors"
 	"golang.org/x/crypto/chacha20poly1305"
 	"lukechampine.com/blake3"
@@ -31,15 +33,14 @@ type CommonConn struct {
 	AEAD        *AEAD
 	PeerAEAD    *AEAD
 	PeerPadding []byte
-	PeerInBytes []byte
-	PeerCache   []byte
+	rawInput    bytes.Buffer
+	input       bytes.Reader
 }
 
 func NewCommonConn(conn net.Conn, useAES bool) *CommonConn {
 	return &CommonConn{
-		Conn:        conn,
-		UseAES:      useAES,
-		PeerInBytes: make([]byte, 5+17000), // no need to use sync.Pool, because we are always reading
+		Conn:   conn,
+		UseAES: useAES,
 	}
 }
 
@@ -99,16 +100,14 @@ func (c *CommonConn) Read(b []byte) (int, error) {
 		}
 		c.PeerPadding = nil
 	}
-	if len(c.PeerCache) > 0 {
-		n := copy(b, c.PeerCache)
-		c.PeerCache = c.PeerCache[n:]
-		return n, nil
+	if c.input.Len() > 0 {
+		return c.input.Read(b)
 	}
-	peerHeader := c.PeerInBytes[:5]
-	if _, err := io.ReadFull(c.Conn, peerHeader); err != nil {
+	peerHeader := [5]byte{}
+	if _, err := io.ReadFull(c.Conn, peerHeader[:]); err != nil {
 		return 0, err
 	}
-	l, err := DecodeHeader(c.PeerInBytes[:5]) // l: 17~17000
+	l, err := DecodeHeader(peerHeader[:]) // l: 17~17000
 	if err != nil {
 		if c.Client != nil && strings.Contains(err.Error(), "invalid header: ") { // client's 0-RTT
 			c.Client.RWLock.Lock()
@@ -121,7 +120,10 @@ func (c *CommonConn) Read(b []byte) (int, error) {
 		return 0, err
 	}
 	c.Client = nil
-	peerData := c.PeerInBytes[5 : 5+l]
+	if c.rawInput.Cap() < l {
+		c.rawInput.Grow(l) // no need to use sync.Pool, because we are always reading
+	}
+	peerData := c.rawInput.Bytes()[:l]
 	if _, err := io.ReadFull(c.Conn, peerData); err != nil {
 		return 0, err
 	}
@@ -131,9 +133,9 @@ func (c *CommonConn) Read(b []byte) (int, error) {
 	}
 	var newAEAD *AEAD
 	if bytes.Equal(c.PeerAEAD.Nonce[:], MaxNonce) {
-		newAEAD = NewAEAD(c.PeerInBytes[:5+l], c.UnitedKey, c.UseAES)
+		newAEAD = NewAEAD(append(peerHeader[:], peerData...), c.UnitedKey, c.UseAES)
 	}
-	_, err = c.PeerAEAD.Open(dst[:0], nil, peerData, peerHeader)
+	_, err = c.PeerAEAD.Open(dst[:0], nil, peerData, peerHeader[:])
 	if newAEAD != nil {
 		c.PeerAEAD = newAEAD
 	}
@@ -141,7 +143,7 @@ func (c *CommonConn) Read(b []byte) (int, error) {
 		return 0, err
 	}
 	if len(dst) > len(b) {
-		c.PeerCache = dst[copy(b, dst):]
+		c.input.Reset(dst[copy(b, dst):])
 		dst = b // for len(dst)
 	}
 	return len(dst), nil
@@ -213,7 +215,55 @@ func DecodeHeader(h []byte) (l int, err error) {
 		l = 0
 	}
 	if l < 17 || l > 17000 { // TODO: TLSv1.3 max length
-		err = errors.New("invalid header: ", fmt.Sprintf("%v", h[:5])) // DO NOT CHANGE: relied by client's Read()
+		err = errors.New("invalid header: " + fmt.Sprintf("%v", h[:5])) // DO NOT CHANGE: relied by client's Read()
+	}
+	return
+}
+
+func ParsePadding(padding string, paddingLens, paddingGaps *[][2]int) (err error) {
+	if padding == "" {
+		return
+	}
+	maxLen := 0
+	for i, s := range strings.Split(padding, ".") {
+		x := strings.SplitN(s, "-", 2)
+		if len(x) != 2 || x[0] == "" || x[1] == "" {
+			return errors.New("invalid padding lenth/gap parameter: " + s)
+		}
+		y := [2]int{}
+		if y[0], err = strconv.Atoi(x[0]); err != nil {
+			return
+		}
+		if y[1], err = strconv.Atoi(x[1]); err != nil {
+			return
+		}
+		if i == 0 && (y[0] < 17 || y[1] < 17) {
+			return errors.New("first padding length must be larger than 16")
+		}
+		if i%2 == 0 {
+			*paddingLens = append(*paddingLens, y)
+			maxLen += max(y[0], y[1])
+		} else {
+			*paddingGaps = append(*paddingGaps, y)
+		}
+	}
+	if maxLen > 65535 {
+		return errors.New("total padding length must be smaller than 65536")
+	}
+	return
+}
+
+func CreatPadding(paddingLens, paddingGaps [][2]int) (length int, lens []int, gaps []time.Duration) {
+	if len(paddingLens) == 0 {
+		paddingLens = [][2]int{{111, 1111}, {3333, -1234}}
+		paddingGaps = [][2]int{{111, -66}}
+	}
+	for _, l := range paddingLens {
+		lens = append(lens, int(max(0, crypto.RandBetween(int64(l[0]), int64(l[1])))))
+		length += lens[len(lens)-1]
+	}
+	for _, g := range paddingGaps {
+		gaps = append(gaps, time.Duration(max(0, crypto.RandBetween(int64(g[0]), int64(g[1]))))*time.Millisecond)
 	}
 	return
 }