Added tcp fragmentation for freedom outbound (#2021)

* Added tcp fragmentation for freedom outbound * Added TCP_NODELAY to outbound sockopt * Changed fragment parameters to accept ranges and changed strategy to use length * Changed packetNumber to packets, supporting range. * Refactored the freedom fragment logic * Refine Write() --------- Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>
XTLS · May 22, 2023 · 5f5ae37 · 5f5ae37
1 parent c80646a
commit 5f5ae37
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Showing 10 changed files with 392 additions and 71 deletions.
diff --git a/infra/conf/freedom.go b/infra/conf/freedom.go
@@ -2,6 +2,7 @@ package conf
 
 import (
 	"net"
+	"strconv"
 	"strings"
 
 	"github.com/golang/protobuf/proto"
@@ -11,10 +12,17 @@ import (
 )
 
 type FreedomConfig struct {
-	DomainStrategy string  `json:"domainStrategy"`
-	Timeout        *uint32 `json:"timeout"`
-	Redirect       string  `json:"redirect"`
-	UserLevel      uint32  `json:"userLevel"`
+	DomainStrategy string    `json:"domainStrategy"`
+	Timeout        *uint32   `json:"timeout"`
+	Redirect       string    `json:"redirect"`
+	UserLevel      uint32    `json:"userLevel"`
+	Fragment       *Fragment `json:"fragment"`
+}
+
+type Fragment struct {
+	Packets  string `json:"packets"`
+	Length   string `json:"length"`
+	Interval string `json:"interval"`
 }
 
 // Build implements Buildable
@@ -30,6 +38,88 @@ func (c *FreedomConfig) Build() (proto.Message, error) {
 		config.DomainStrategy = freedom.Config_USE_IP6
 	}
 
+	if c.Fragment != nil {
+		if len(c.Fragment.Interval) == 0 || len(c.Fragment.Length) == 0 {
+			return nil, newError("Invalid interval or length")
+		}
+		intervalMinMax := strings.Split(c.Fragment.Interval, "-")
+		var minInterval, maxInterval int64
+		var err, err2 error
+		if len(intervalMinMax) == 2 {
+			minInterval, err = strconv.ParseInt(intervalMinMax[0], 10, 64)
+			maxInterval, err2 = strconv.ParseInt(intervalMinMax[1], 10, 64)
+		} else {
+			minInterval, err = strconv.ParseInt(intervalMinMax[0], 10, 64)
+			maxInterval = minInterval
+		}
+		if err != nil {
+			return nil, newError("Invalid minimum interval: ", err).Base(err)
+		}
+		if err2 != nil {
+			return nil, newError("Invalid maximum interval: ", err2).Base(err2)
+		}
+
+		lengthMinMax := strings.Split(c.Fragment.Length, "-")
+		var minLength, maxLength int64
+		if len(lengthMinMax) == 2 {
+			minLength, err = strconv.ParseInt(lengthMinMax[0], 10, 64)
+			maxLength, err2 = strconv.ParseInt(lengthMinMax[1], 10, 64)
+
+		} else {
+			minLength, err = strconv.ParseInt(lengthMinMax[0], 10, 64)
+			maxLength = minLength
+		}
+		if err != nil {
+			return nil, newError("Invalid minimum length: ", err).Base(err)
+		}
+		if err2 != nil {
+			return nil, newError("Invalid maximum length: ", err2).Base(err2)
+		}
+
+		if minInterval > maxInterval {
+			minInterval, maxInterval = maxInterval, minInterval
+		}
+		if minLength > maxLength {
+			minLength, maxLength = maxLength, minLength
+		}
+
+		config.Fragment = &freedom.Fragment{
+			MinInterval: int32(minInterval),
+			MaxInterval: int32(maxInterval),
+			MinLength:   int32(minLength),
+			MaxLength:   int32(maxLength),
+		}
+
+		if len(c.Fragment.Packets) > 0 {
+			packetRange := strings.Split(c.Fragment.Packets, "-")
+			var startPacket, endPacket int64
+			if len(packetRange) == 2 {
+				startPacket, err = strconv.ParseInt(packetRange[0], 10, 64)
+				endPacket, err2 = strconv.ParseInt(packetRange[1], 10, 64)
+			} else {
+				startPacket, err = strconv.ParseInt(packetRange[0], 10, 64)
+				endPacket = startPacket
+			}
+			if err != nil {
+				return nil, newError("Invalid start packet: ", err).Base(err)
+			}
+			if err2 != nil {
+				return nil, newError("Invalid end packet: ", err2).Base(err2)
+			}
+			if startPacket > endPacket {
+				return nil, newError("Invalid packet range: ", c.Fragment.Packets)
+			}
+			if startPacket < 1 {
+				return nil, newError("Cannot start from packet 0")
+			}
+			config.Fragment.StartPacket = int32(startPacket)
+			config.Fragment.EndPacket = int32(endPacket)
+		} else {
+			config.Fragment.StartPacket = 0
+			config.Fragment.EndPacket = 0
+		}
+	}
+
 	if c.Timeout != nil {
 		config.Timeout = *c.Timeout
 	}

diff --git a/infra/conf/transport_internet.go b/infra/conf/transport_internet.go
@@ -617,7 +617,8 @@ type SocketConfig struct {
 	TCPKeepAliveIdle     int32       `json:"tcpKeepAliveIdle"`
 	TCPCongestion        string      `json:"tcpCongestion"`
 	TCPWindowClamp       int32       `json:"tcpWindowClamp"`
-	TCPMaxSeg	     int32	 `json:"tcpMaxSeg"`
+	TCPMaxSeg            int32       `json:"tcpMaxSeg"`
+	TcpNoDelay           bool        `json:"tcpNoDelay"`
 	TCPUserTimeout       int32       `json:"tcpUserTimeout"`
 	V6only               bool        `json:"v6only"`
 	Interface            string      `json:"interface"`
@@ -671,7 +672,8 @@ func (c *SocketConfig) Build() (*internet.SocketConfig, error) {
 		TcpKeepAliveIdle:     c.TCPKeepAliveIdle,
 		TcpCongestion:        c.TCPCongestion,
 		TcpWindowClamp:       c.TCPWindowClamp,
-		TcpMaxSeg:	      c.TCPMaxSeg,
+		TcpMaxSeg:            c.TCPMaxSeg,
+		TcpNoDelay:           c.TcpNoDelay,
 		TcpUserTimeout:       c.TCPUserTimeout,
 		V6Only:               c.V6only,
 		Interface:            c.Interface,