Improve: refactor ssr and fix #995 (#1189)

Co-authored-by: goomada <madao@DESKTOP-IOEBS0C.localdomain>

component/ssr/protocol/auth_chain_b.go

@@ -1,71 +1,96 @@
 package protocol
 
 import (
+	"net"
 	"sort"
 
 	"github.com/Dreamacro/clash/component/ssr/tools"
 )
 
 func init() {
-	register("auth_chain_b", newAuthChainB)
+	register("auth_chain_b", newAuthChainB, 4)
+}
+
+type authChainB struct {
+	*authChainA
+	dataSizeList  []int
+	dataSizeList2 []int
 }
 
 func newAuthChainB(b *Base) Protocol {
-	return &authChain{
-		Base:       b,
-		authData:   &authData{},
-		salt:       "auth_chain_b",
-		hmac:       tools.HmacMD5,
-		hashDigest: tools.SHA1Sum,
-		rnd:        authChainBGetRandLen,
+	a := &authChainB{
+		authChainA: &authChainA{
+			Base:     b,
+			authData: &authData{},
+			userData: &userData{},
+			salt:     "auth_chain_b",
+		},
 	}
+	a.initUserData()
+	return a
 }
 
-func initDataSize(r *authChain) {
-	random := &r.randomServer
-	random.InitFromBin(r.Key)
-	len := random.Next()%8 + 4
-	r.dataSizeList = make([]int, len)
-	for i := 0; i < int(len); i++ {
-		r.dataSizeList[i] = int(random.Next() % 2340 % 2040 % 1440)
+func (a *authChainB) StreamConn(c net.Conn, iv []byte) net.Conn {
+	p := &authChainB{
+		authChainA: &authChainA{
+			Base:     a.Base,
+			authData: a.next(),
+			userData: a.userData,
+			salt:     a.salt,
+			packID:   1,
+			recvID:   1,
+		},
 	}
-	sort.Ints(r.dataSizeList)
-
-	len = random.Next()%16 + 8
-	r.dataSizeList2 = make([]int, len)
-	for i := 0; i < int(len); i++ {
-		r.dataSizeList2[i] = int(random.Next() % 2340 % 2040 % 1440)
-	}
-	sort.Ints(r.dataSizeList2)
+	p.iv = iv
+	p.randDataLength = p.getRandLength
+	p.initDataSize()
+	return &Conn{Conn: c, Protocol: p}
 }
 
-func authChainBGetRandLen(dataLength int, random *shift128PlusContext, lastHash []byte, dataSizeList, dataSizeList2 []int, overhead int) int {
-	if dataLength > 1440 {
+func (a *authChainB) initDataSize() {
+	a.dataSizeList = a.dataSizeList[:0]
+	a.dataSizeList2 = a.dataSizeList2[:0]
+
+	a.randomServer.InitFromBin(a.Key)
+	length := a.randomServer.Next()%8 + 4
+	for ; length > 0; length-- {
+		a.dataSizeList = append(a.dataSizeList, int(a.randomServer.Next()%2340%2040%1440))
+	}
+	sort.Ints(a.dataSizeList)
+
+	length = a.randomServer.Next()%16 + 8
+	for ; length > 0; length-- {
+		a.dataSizeList2 = append(a.dataSizeList2, int(a.randomServer.Next()%2340%2040%1440))
+	}
+	sort.Ints(a.dataSizeList2)
+}
+
+func (a *authChainB) getRandLength(length int, lashHash []byte, random *tools.XorShift128Plus) int {
+	if length >= 1440 {
 		return 0
 	}
-	random.InitFromBinDatalen(lastHash[:16], dataLength)
-	pos := sort.Search(len(dataSizeList), func(i int) bool { return dataSizeList[i] > dataLength+overhead })
-	finalPos := uint64(pos) + random.Next()%uint64(len(dataSizeList))
-	if finalPos < uint64(len(dataSizeList)) {
-		return dataSizeList[finalPos] - dataLength - overhead
+	random.InitFromBinAndLength(lashHash, length)
+	pos := sort.Search(len(a.dataSizeList), func(i int) bool { return a.dataSizeList[i] >= length+a.Overhead })
+	finalPos := pos + int(random.Next()%uint64(len(a.dataSizeList)))
+	if finalPos < len(a.dataSizeList) {
+		return a.dataSizeList[finalPos] - length - a.Overhead
 	}
 
-	pos = sort.Search(len(dataSizeList2), func(i int) bool { return dataSizeList2[i] > dataLength+overhead })
-	finalPos = uint64(pos) + random.Next()%uint64(len(dataSizeList2))
-	if finalPos < uint64(len(dataSizeList2)) {
-		return dataSizeList2[finalPos] - dataLength - overhead
+	pos = sort.Search(len(a.dataSizeList2), func(i int) bool { return a.dataSizeList2[i] >= length+a.Overhead })
+	finalPos = pos + int(random.Next()%uint64(len(a.dataSizeList2)))
+	if finalPos < len(a.dataSizeList2) {
+		return a.dataSizeList2[finalPos] - length - a.Overhead
 	}
-	if finalPos < uint64(pos+len(dataSizeList2)-1) {
+	if finalPos < pos+len(a.dataSizeList2)-1 {
 		return 0
 	}
-
-	if dataLength > 1300 {
+	if length > 1300 {
 		return int(random.Next() % 31)
 	}
-	if dataLength > 900 {
+	if length > 900 {
 		return int(random.Next() % 127)
 	}
-	if dataLength > 400 {
+	if length > 400 {
 		return int(random.Next() % 521)
 	}
 	return int(random.Next() % 1021)