XHTTP transport: Add sessionIDTable and sessionIDLength; Rename session* to sessionID*

infra/conf/transport_internet.go

@@ -6,6 +6,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"math"
+	"math/big"
 	"net/netip"
 	"net/url"
 	"os"
@@ -219,8 +220,10 @@ type SplitHTTPConfig struct {
 	XPaddingPlacement    string            `json:"xPaddingPlacement"`
 	XPaddingMethod       string            `json:"xPaddingMethod"`
 	UplinkHTTPMethod     string            `json:"uplinkHTTPMethod"`
-	SessionPlacement     string            `json:"sessionPlacement"`
-	SessionKey           string            `json:"sessionKey"`
+	SessionIDPlacement   string            `json:"sessionIDPlacement"`
+	SessionIDKey         string            `json:"sessionIDKey"`
+	SessionIDTable       string            `json:"sessionIDTable"`
+	SessionIDLength      Int32Range        `json:"sessionIDLength"`
 	SeqPlacement         string            `json:"seqPlacement"`
 	SeqKey               string            `json:"seqKey"`
 	UplinkDataPlacement  string            `json:"uplinkDataPlacement"`
@@ -331,12 +334,12 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 		return nil, errors.New("uplinkHTTPMethod can be GET only in packet-up mode")
 	}
 
-	switch c.SessionPlacement {
+	switch c.SessionIDPlacement {
 	case "":
-		c.SessionPlacement = "path"
+		c.SessionIDPlacement = "path"
 	case "path", "cookie", "header", "query":
 	default:
-		return nil, errors.New("unsupported session placement: " + c.SessionPlacement)
+		return nil, errors.New("unsupported session placement: " + c.SessionIDPlacement)
 	}
 
 	switch c.SeqPlacement {
@@ -347,12 +350,31 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 		return nil, errors.New("unsupported seq placement: " + c.SeqPlacement)
 	}
 
-	if c.SessionPlacement != "path" && c.SessionKey == "" {
-		switch c.SessionPlacement {
+	if c.SessionIDPlacement != "path" && c.SessionIDKey == "" {
+		switch c.SessionIDPlacement {
 		case "cookie", "query":
-			c.SessionKey = "x_session"
+			c.SessionIDKey = "x_session"
 		case "header":
-			c.SessionKey = "X-Session"
+			c.SessionIDKey = "X-Session"
+		}
+	}
+
+	if c.SessionIDTable != "" {
+		if predefined, ok := splithttp.PredefinedTable[c.SessionIDTable]; ok {
+			c.SessionIDTable = predefined
+		}
+		room := roomSize(len(c.SessionIDTable), c.SessionIDLength.From, c.SessionIDLength.To)
+		// 2.1B possiblities should be enough
+		if room.Cmp(big.NewInt(2<<30)) < 0 {
+			return nil, errors.New("sessionIDTable or sessionIDLength is too small")
+		}
+		if c.SessionIDLength.From <= 0 {
+			return nil, errors.New("sessionIDLength.from must be greater than 0")
+		}
+		for i := 0; i < len(c.SessionIDTable); i++ {
+			if c.SessionIDTable[i] >= 0x80 {
+				return nil, errors.New("sessionIDTable must contain only ASCII characters")
+			}
 		}
 	}
 
@@ -402,9 +424,9 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 		XPaddingPlacement:    c.XPaddingPlacement,
 		XPaddingMethod:       c.XPaddingMethod,
 		UplinkHTTPMethod:     c.UplinkHTTPMethod,
-		SessionPlacement:     c.SessionPlacement,
+		SessionIDPlacement:   c.SessionIDPlacement,
 		SeqPlacement:         c.SeqPlacement,
-		SessionKey:           c.SessionKey,
+		SessionIDKey:         c.SessionIDKey,
 		SeqKey:               c.SeqKey,
 		UplinkDataPlacement:  c.UplinkDataPlacement,
 		UplinkDataKey:        c.UplinkDataKey,
@@ -416,6 +438,8 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 		ScMaxBufferedPosts:   c.ScMaxBufferedPosts,
 		ScStreamUpServerSecs: newRangeConfig(c.ScStreamUpServerSecs),
 		ServerMaxHeaderBytes: c.ServerMaxHeaderBytes,
+		SessionIDTable:       c.SessionIDTable,
+		SessionIDLength:      newRangeConfig(c.SessionIDLength),
 		Xmux: &splithttp.XmuxConfig{
 			MaxConcurrency:   newRangeConfig(c.Xmux.MaxConcurrency),
 			MaxConnections:   newRangeConfig(c.Xmux.MaxConnections),
@@ -439,6 +463,17 @@ func (c *SplitHTTPConfig) Build() (proto.Message, error) {
 	return config, nil
 }
 
+func roomSize(tableSize int, min, max int32) *big.Int {
+	base := big.NewInt(int64(tableSize))
+	sum := new(big.Int)
+	term := new(big.Int)
+	for k := min; k <= max; k++ {
+		term.Exp(base, big.NewInt(int64(k)), nil)
+		sum.Add(sum, term)
+	}
+	return sum
+}
+
 const (
 	Byte     = 1
 	Kilobyte = 1024 * Byte

transport/internet/splithttp/config.go

@@ -4,13 +4,15 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
+	"math/rand/v2"
 	"net/http"
 	"strings"
 
 	"github.com/xtls/xray-core/common"
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/crypto"
 	"github.com/xtls/xray-core/common/utils"
+	"github.com/xtls/xray-core/common/uuid"
 	"github.com/xtls/xray-core/transport/internet"
 )
 
@@ -131,26 +133,26 @@ func (c *Config) GetNormalizedUplinkHTTPMethod() string {
 	return c.UplinkHTTPMethod
 }
 
-func (c *Config) GetNormalizedScMaxEachPostBytes() RangeConfig {
+func (c *Config) GetNormalizedScMaxEachPostBytes() *RangeConfig {
 	if c.ScMaxEachPostBytes == nil || c.ScMaxEachPostBytes.To == 0 {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 1000000,
 			To:   1000000,
 		}
 	}
 
-	return *c.ScMaxEachPostBytes
+	return c.ScMaxEachPostBytes
 }
 
-func (c *Config) GetNormalizedScMinPostsIntervalMs() RangeConfig {
+func (c *Config) GetNormalizedScMinPostsIntervalMs() *RangeConfig {
 	if c.ScMinPostsIntervalMs == nil || c.ScMinPostsIntervalMs.To == 0 {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 30,
 			To:   30,
 		}
 	}
 
-	return *c.ScMinPostsIntervalMs
+	return c.ScMinPostsIntervalMs
 }
 
 func (c *Config) GetNormalizedScMaxBufferedPosts() int {
@@ -161,41 +163,41 @@ func (c *Config) GetNormalizedScMaxBufferedPosts() int {
 	return int(c.ScMaxBufferedPosts)
 }
 
-func (c *Config) GetNormalizedScStreamUpServerSecs() RangeConfig {
+func (c *Config) GetNormalizedScStreamUpServerSecs() *RangeConfig {
 	if c.ScStreamUpServerSecs == nil || c.ScStreamUpServerSecs.To == 0 {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 20,
 			To:   80,
 		}
 	}
 
-	return *c.ScStreamUpServerSecs
+	return c.ScStreamUpServerSecs
 }
 
-func (c *Config) GetNormalizedUplinkChunkSize() RangeConfig {
+func (c *Config) GetNormalizedUplinkChunkSize() *RangeConfig {
 	if c.UplinkChunkSize == nil || c.UplinkChunkSize.To == 0 {
 		switch c.UplinkDataPlacement {
 		case PlacementCookie:
-			return RangeConfig{
+			return &RangeConfig{
 				From: 2 * 1024, // 2 KiB
 				To:   3 * 1024, // 3 KiB
 			}
 		case PlacementHeader:
-			return RangeConfig{
+			return &RangeConfig{
 				From: 3 * 1000, // 3 KB
 				To:   4 * 1000, // 4 KB
 			}
 		default:
 			return c.GetNormalizedScMaxEachPostBytes()
 		}
 	} else if c.UplinkChunkSize.From < 64 {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 64,
 			To:   max(64, c.UplinkChunkSize.To),
 		}
 	}
 
-	return *c.UplinkChunkSize
+	return c.UplinkChunkSize
 }
 
 func (c *Config) GetNormalizedServerMaxHeaderBytes() int {
@@ -207,10 +209,10 @@ func (c *Config) GetNormalizedServerMaxHeaderBytes() int {
 }
 
 func (c *Config) GetNormalizedSessionPlacement() string {
-	if c.SessionPlacement == "" {
+	if c.SessionIDPlacement == "" {
 		return PlacementPath
 	}
-	return c.SessionPlacement
+	return c.SessionIDPlacement
 }
 
 func (c *Config) GetNormalizedSeqPlacement() string {
@@ -228,8 +230,8 @@ func (c *Config) GetNormalizedUplinkDataPlacement() string {
 }
 
 func (c *Config) GetNormalizedSessionKey() string {
-	if c.SessionKey != "" {
-		return c.SessionKey
+	if c.SessionIDKey != "" {
+		return c.SessionIDKey
 	}
 	switch c.GetNormalizedSessionPlacement() {
 	case PlacementHeader:
@@ -417,59 +419,59 @@ func (c *Config) ExtractMetaFromRequest(req *http.Request, path string) (session
 	return sessionId, seqStr
 }
 
-func (m *XmuxConfig) GetNormalizedMaxConcurrency() RangeConfig {
+func (m *XmuxConfig) GetNormalizedMaxConcurrency() *RangeConfig {
 	if m.MaxConcurrency == nil {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 0,
 			To:   0,
 		}
 	}
 
-	return *m.MaxConcurrency
+	return m.MaxConcurrency
 }
 
-func (m *XmuxConfig) GetNormalizedMaxConnections() RangeConfig {
+func (m *XmuxConfig) GetNormalizedMaxConnections() *RangeConfig {
 	if m.MaxConnections == nil {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 0,
 			To:   0,
 		}
 	}
 
-	return *m.MaxConnections
+	return m.MaxConnections
 }
 
-func (m *XmuxConfig) GetNormalizedCMaxReuseTimes() RangeConfig {
+func (m *XmuxConfig) GetNormalizedCMaxReuseTimes() *RangeConfig {
 	if m.CMaxReuseTimes == nil {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 0,
 			To:   0,
 		}
 	}
 
-	return *m.CMaxReuseTimes
+	return m.CMaxReuseTimes
 }
 
-func (m *XmuxConfig) GetNormalizedHMaxRequestTimes() RangeConfig {
+func (m *XmuxConfig) GetNormalizedHMaxRequestTimes() *RangeConfig {
 	if m.HMaxRequestTimes == nil {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 0,
 			To:   0,
 		}
 	}
 
-	return *m.HMaxRequestTimes
+	return m.HMaxRequestTimes
 }
 
-func (m *XmuxConfig) GetNormalizedHMaxReusableSecs() RangeConfig {
+func (m *XmuxConfig) GetNormalizedHMaxReusableSecs() *RangeConfig {
 	if m.HMaxReusableSecs == nil {
-		return RangeConfig{
+		return &RangeConfig{
 			From: 0,
 			To:   0,
 		}
 	}
 
-	return *m.HMaxReusableSecs
+	return m.HMaxReusableSecs
 }
 
 func init() {
@@ -478,10 +480,44 @@ func init() {
 	}))
 }
 
-func (c RangeConfig) rand() int32 {
+func (c *RangeConfig) rand() int32 {
+	if c == nil {
+		return 0
+	}
 	return int32(crypto.RandBetween(int64(c.From), int64(c.To)))
 }
 
+// predefined
+var PredefinedTable = map[string]string{
+	"ALPHABET": "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+	"Alphabet": "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+	"BASE36":   "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+	"Base62":   "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+	"HEX":      "0123456789ABCDEF",
+	"alphabet": "abcdefghijklmnopqrstuvwxyz",
+	"base36":   "0123456789abcdefghijklmnopqrstuvwxyz",
+	"hex":      "0123456789abcdef",
+	"number":   "0123456789",
+}
+
+func (c *Config) GenerateSessionID() string {
+	length := c.SessionIDLength.rand()
+	table := c.SessionIDTable
+	if predefined, ok := PredefinedTable[table]; ok {
+		table = predefined
+	}
+	if table != "" && length > 0 {
+		id := make([]byte, length)
+		for i := range id {
+			id[i] = table[rand.N(len(table))]
+		}
+		return string(id)
+	} else {
+		uuid := uuid.New()
+		return uuid.String()
+	}
+}
+
 func appendToPath(path, value string) string {
 	if strings.HasSuffix(path, "/") {
 		return path + value