chore: Add vision splice support

go.mod

@@ -105,6 +105,6 @@ require (
 	golang.org/x/tools v0.6.0 // indirect
 )
 
-replace github.com/sagernet/sing => github.com/h1jk/sing v0.0.0-20230519121640-6db84f45244d
+replace github.com/sagernet/sing => github.com/metacubex/sing v0.0.0-20230526162852-6afe73474070
 
 replace github.com/sagernet/sing-vmess => github.com/metacubex/sing-vmess v0.1.5-0.20230520082358-78b126617899

go.sum

@@ -65,8 +65,6 @@ github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38/go.mod h1:kpwsk12EmLe
 github.com/google/tink/go v1.6.1 h1:t7JHqO8Ath2w2ig5vjwQYJzhGEZymedQc90lQXUBa4I=
 github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/h1jk/sing v0.0.0-20230519121640-6db84f45244d h1:ih6tNzl1uxuuX+Naz2qAPqSS20E6jfXFmcvyDRAy8rY=
-github.com/h1jk/sing v0.0.0-20230519121640-6db84f45244d/go.mod h1:Ta8nHnDLAwqySzKhGoKk4ZIB+vJ3GTKj7UPrWYvM+4w=
 github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hashicorp/yamux v0.1.1 h1:yrQxtgseBDrq9Y652vSRDvsKCJKOUD+GzTS4Y0Y8pvE=
@@ -98,6 +96,8 @@ github.com/metacubex/gvisor v0.0.0-20230417114019-3c3ee672d60c h1:D62872jiuzC6b+
 github.com/metacubex/gvisor v0.0.0-20230417114019-3c3ee672d60c/go.mod h1:wqEuzdImyqD2MCGE8CYRJXbB77oSEJeoSSXXdwKjnsE=
 github.com/metacubex/quic-go v0.33.3-0.20230510010206-687b537b6a58 h1:E/sNW9tugFjoBjAkth89MHlKHRaMdo43tGQ3MOPVayQ=
 github.com/metacubex/quic-go v0.33.3-0.20230510010206-687b537b6a58/go.mod h1:9nOiGX6kqV3+ZbkDKdTNzdFD726QQHPH6WDb36jUSpA=
+github.com/metacubex/sing v0.0.0-20230526162852-6afe73474070 h1:AT/Qfe9MvCxyrI9uybcXcVDLDEqR6+9ZK7a7pgis9xQ=
+github.com/metacubex/sing v0.0.0-20230526162852-6afe73474070/go.mod h1:Ta8nHnDLAwqySzKhGoKk4ZIB+vJ3GTKj7UPrWYvM+4w=
 github.com/metacubex/sing-shadowsocks v0.2.2-0.20230509230448-a5157cc00a1c h1:LpVNvlW/xE+mR8z76xJeYZlYznZXEmU4TeWeuygYdJg=
 github.com/metacubex/sing-shadowsocks v0.2.2-0.20230509230448-a5157cc00a1c/go.mod h1:4uQQReKMTU7KTfOykVBe/oGJ00pl38d+BYJ99+mx26s=
 github.com/metacubex/sing-shadowsocks2 v0.0.0-20230519030442-556ef530768f h1:aWgVMoAm5V2Ur9key6L//mUSBrVMl/zw/4GDG4ZjyZI=

transport/vless/vision/conn.go

@@ -262,13 +262,43 @@ func (vc *Conn) WriteBuffer(buffer *buf.Buffer) (err error) {
 }
 
 func (vc *Conn) FrontHeadroom() int {
+	if vc.readFilterUUID {
 		return PaddingHeaderLen
 	}
+	return PaddingHeaderLen - uuid.Size
+}
 
 func (vc *Conn) NeedHandshake() bool {
 	return vc.needHandshake
 }
 
 func (vc *Conn) Upstream() any {
+	if vc.writeDirect ||
+		vc.readLastCommand == commandPaddingDirect {
+		return vc.Conn
+	}
 	return vc.upstream
 }
+
+func (vc *Conn) ReaderPossiblyReplaceable() bool {
+	return vc.readProcess
+}
+
+func (vc *Conn) ReaderReplaceable() bool {
+	if !vc.readProcess &&
+		vc.readLastCommand == commandPaddingDirect {
+		return true
+	}
+	return false
+}
+
+func (vc *Conn) WriterPossiblyReplaceable() bool {
+	return vc.writeFilterApplicationData
+}
+
+func (vc *Conn) WriterReplaceable() bool {
+	if vc.writeDirect {
+		return true
+	}
+	return false
+}