Feature: add load-balance group

adapters/outbound/loadbalance.go

@@ -0,0 +1,94 @@
+package adapters
+
+import (
+	"encoding/json"
+	"errors"
+	"net"
+
+	"github.com/Dreamacro/clash/common/murmur3"
+	C "github.com/Dreamacro/clash/constant"
+
+	"golang.org/x/net/publicsuffix"
+)
+
+type LoadBalance struct {
+	*Base
+	proxies  []C.Proxy
+	maxRetry int
+}
+
+func getKey(metadata *C.Metadata) string {
+	if metadata.Host != "" {
+		// ip host
+		if ip := net.ParseIP(metadata.Host); ip != nil {
+			return metadata.Host
+		}
+
+		if etld, err := publicsuffix.EffectiveTLDPlusOne(metadata.Host); err == nil {
+			return etld
+		}
+	}
+
+	if metadata.IP == nil {
+		return ""
+	}
+
+	return metadata.IP.String()
+}
+
+func jumpHash(key uint64, buckets int32) int32 {
+	var b, j int64
+
+	for j < int64(buckets) {
+		b = j
+		key = key*2862933555777941757 + 1
+		j = int64(float64(b+1) * (float64(int64(1)<<31) / float64((key>>33)+1)))
+	}
+
+	return int32(b)
+}
+
+func (lb *LoadBalance) Generator(metadata *C.Metadata) (net.Conn, error) {
+	key := uint64(murmur3.Sum32([]byte(getKey(metadata))))
+	buckets := int32(len(lb.proxies))
+	for i := 0; i < lb.maxRetry; i++ {
+		idx := jumpHash(key, buckets)
+		if proxy, err := lb.proxies[idx].Generator(metadata); err == nil {
+			return proxy, nil
+		}
+		key++
+	}
+
+	return lb.proxies[0].Generator(metadata)
+}
+
+func (lb *LoadBalance) MarshalJSON() ([]byte, error) {
+	var all []string
+	for _, proxy := range lb.proxies {
+		all = append(all, proxy.Name())
+	}
+	return json.Marshal(map[string]interface{}{
+		"type": lb.Type().String(),
+		"all":  all,
+	})
+}
+
+type LoadBalanceOption struct {
+	Name    string   `proxy:"name"`
+	Proxies []string `proxy:"proxies"`
+}
+
+func NewLoadBalance(name string, proxies []C.Proxy) (*LoadBalance, error) {
+	if len(proxies) == 0 {
+		return nil, errors.New("Provide at least one proxy")
+	}
+
+	return &LoadBalance{
+		Base: &Base{
+			name: name,
+			tp:   C.LoadBalance,
+		},
+		proxies:  proxies,
+		maxRetry: 3,
+	}, nil
+}

common/murmur3/murmur.go

@@ -0,0 +1,50 @@
+package murmur3
+
+type bmixer interface {
+	bmix(p []byte) (tail []byte)
+	Size() (n int)
+	reset()
+}
+
+type digest struct {
+	clen int      // Digested input cumulative length.
+	tail []byte   // 0 to Size()-1 bytes view of `buf'.
+	buf  [16]byte // Expected (but not required) to be Size() large.
+	seed uint32   // Seed for initializing the hash.
+	bmixer
+}
+
+func (d *digest) BlockSize() int { return 1 }
+
+func (d *digest) Write(p []byte) (n int, err error) {
+	n = len(p)
+	d.clen += n
+
+	if len(d.tail) > 0 {
+		// Stick back pending bytes.
+		nfree := d.Size() - len(d.tail) // nfree ∈ [1, d.Size()-1].
+		if nfree < len(p) {
+			// One full block can be formed.
+			block := append(d.tail, p[:nfree]...)
+			p = p[nfree:]
+			_ = d.bmix(block) // No tail.
+		} else {
+			// Tail's buf is large enough to prevent reallocs.
+			p = append(d.tail, p...)
+		}
+	}
+
+	d.tail = d.bmix(p)
+
+	// Keep own copy of the 0 to Size()-1 pending bytes.
+	nn := copy(d.buf[:], d.tail)
+	d.tail = d.buf[:nn]
+
+	return n, nil
+}
+
+func (d *digest) Reset() {
+	d.clen = 0
+	d.tail = nil
+	d.bmixer.reset()
+}

common/murmur3/murmur32.go

@@ -0,0 +1,149 @@
+package murmur3
+
+// https://github.com/spaolacci/murmur3/blob/master/murmur32.go
+
+import (
+	"hash"
+	"unsafe"
+)
+
+// Make sure interfaces are correctly implemented.
+var (
+	_ hash.Hash32 = new(digest32)
+	_ bmixer      = new(digest32)
+)
+
+const (
+	c1_32 uint32 = 0xcc9e2d51
+	c2_32 uint32 = 0x1b873593
+)
+
+// digest32 represents a partial evaluation of a 32 bites hash.
+type digest32 struct {
+	digest
+	h1 uint32 // Unfinalized running hash.
+}
+
+// New32 returns new 32-bit hasher
+func New32() hash.Hash32 { return New32WithSeed(0) }
+
+// New32WithSeed returns new 32-bit hasher set with explicit seed value
+func New32WithSeed(seed uint32) hash.Hash32 {
+	d := new(digest32)
+	d.seed = seed
+	d.bmixer = d
+	d.Reset()
+	return d
+}
+
+func (d *digest32) Size() int { return 4 }
+
+func (d *digest32) reset() { d.h1 = d.seed }
+
+func (d *digest32) Sum(b []byte) []byte {
+	h := d.Sum32()
+	return append(b, byte(h>>24), byte(h>>16), byte(h>>8), byte(h))
+}
+
+// Digest as many blocks as possible.
+func (d *digest32) bmix(p []byte) (tail []byte) {
+	h1 := d.h1
+
+	nblocks := len(p) / 4
+	for i := 0; i < nblocks; i++ {
+		k1 := *(*uint32)(unsafe.Pointer(&p[i*4]))
+
+		k1 *= c1_32
+		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 *= c2_32
+
+		h1 ^= k1
+		h1 = (h1 << 13) | (h1 >> 19) // rotl32(h1, 13)
+		h1 = h1*4 + h1 + 0xe6546b64
+	}
+	d.h1 = h1
+	return p[nblocks*d.Size():]
+}
+
+func (d *digest32) Sum32() (h1 uint32) {
+
+	h1 = d.h1
+
+	var k1 uint32
+	switch len(d.tail) & 3 {
+	case 3:
+		k1 ^= uint32(d.tail[2]) << 16
+		fallthrough
+	case 2:
+		k1 ^= uint32(d.tail[1]) << 8
+		fallthrough
+	case 1:
+		k1 ^= uint32(d.tail[0])
+		k1 *= c1_32
+		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 *= c2_32
+		h1 ^= k1
+	}
+
+	h1 ^= uint32(d.clen)
+
+	h1 ^= h1 >> 16
+	h1 *= 0x85ebca6b
+	h1 ^= h1 >> 13
+	h1 *= 0xc2b2ae35
+	h1 ^= h1 >> 16
+
+	return h1
+}
+
+func Sum32(data []byte) uint32 { return Sum32WithSeed(data, 0) }
+
+func Sum32WithSeed(data []byte, seed uint32) uint32 {
+	h1 := seed
+
+	nblocks := len(data) / 4
+	var p uintptr
+	if len(data) > 0 {
+		p = uintptr(unsafe.Pointer(&data[0]))
+	}
+	p1 := p + uintptr(4*nblocks)
+	for ; p < p1; p += 4 {
+		k1 := *(*uint32)(unsafe.Pointer(p))
+
+		k1 *= c1_32
+		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 *= c2_32
+
+		h1 ^= k1
+		h1 = (h1 << 13) | (h1 >> 19) // rotl32(h1, 13)
+		h1 = h1*4 + h1 + 0xe6546b64
+	}
+
+	tail := data[nblocks*4:]
+
+	var k1 uint32
+	switch len(tail) & 3 {
+	case 3:
+		k1 ^= uint32(tail[2]) << 16
+		fallthrough
+	case 2:
+		k1 ^= uint32(tail[1]) << 8
+		fallthrough
+	case 1:
+		k1 ^= uint32(tail[0])
+		k1 *= c1_32
+		k1 = (k1 << 15) | (k1 >> 17) // rotl32(k1, 15)
+		k1 *= c2_32
+		h1 ^= k1
+	}
+
+	h1 ^= uint32(len(data))
+
+	h1 ^= h1 >> 16
+	h1 *= 0x85ebca6b
+	h1 ^= h1 >> 13
+	h1 *= 0xc2b2ae35
+	h1 ^= h1 >> 16
+
+	return h1
+}

config/config.go

@@ -195,7 +195,7 @@ func parseProxies(cfg *rawConfig) (map[string]C.Proxy, error) {
 		}
 
 		var proxy C.Proxy
-		var err error
+		err := fmt.Errorf("can't parse")
 		switch proxyType {
 		case "ss":
 			ssOption := &adapters.ShadowSocksOption{}
@@ -251,8 +251,9 @@ func parseProxies(cfg *rawConfig) (map[string]C.Proxy, error) {
 			return nil, fmt.Errorf("ProxyGroup %s: the duplicate name", groupName)
 		}
 		var group C.Proxy
-		var ps []C.Proxy
+		ps := []C.Proxy{}
-		var err error
+
+		err := fmt.Errorf("can't parse")
 		switch groupType {
 		case "url-test":
 			urlTestOption := &adapters.URLTestOption{}
@@ -290,6 +291,18 @@ func parseProxies(cfg *rawConfig) (map[string]C.Proxy, error) {
 				return nil, fmt.Errorf("ProxyGroup %s: %s", groupName, err.Error())
 			}
 			group, err = adapters.NewFallback(*fallbackOption, ps)
+		case "load-balance":
+			loadBalanceOption := &adapters.LoadBalanceOption{}
+			err = decoder.Decode(mapping, loadBalanceOption)
+			if err != nil {
+				break
+			}
+
+			ps, err = getProxies(proxies, loadBalanceOption.Proxies)
+			if err != nil {
+				return nil, fmt.Errorf("ProxyGroup %s: %s", groupName, err.Error())
+			}
+			group, err = adapters.NewLoadBalance(loadBalanceOption.Name, ps)
 		}
 		if err != nil {
 			return nil, fmt.Errorf("Proxy %s: %s", groupName, err.Error())
@@ -297,7 +310,7 @@ func parseProxies(cfg *rawConfig) (map[string]C.Proxy, error) {
 		proxies[groupName] = group
 	}
 
-	var ps []C.Proxy
+	ps := []C.Proxy{}
 	for _, v := range proxies {
 		ps = append(ps, v)
 	}

constant/adapters.go

@@ -15,6 +15,7 @@ const (
 	Http
 	URLTest
 	Vmess
+	LoadBalance
 )
 
 type ServerAdapter interface {
@@ -52,6 +53,8 @@ func (at AdapterType) String() string {
 		return "URLTest"
 	case Vmess:
 		return "Vmess"
+	case LoadBalance:
+		return "LoadBalance"
 	default:
 		return "Unknow"
 	}

go.mod

@@ -13,7 +13,7 @@ require (
 	github.com/oschwald/maxminddb-golang v1.3.0 // indirect
 	github.com/sirupsen/logrus v1.3.0
 	golang.org/x/crypto v0.0.0-20190131182504-b8fe1690c613
-	golang.org/x/net v0.0.0-20181108082009-03003ca0c849 // indirect
+	golang.org/x/net v0.0.0-20181108082009-03003ca0c849
 	golang.org/x/sync v0.0.0-20181108010431-42b317875d0f // indirect
 	gopkg.in/eapache/channels.v1 v1.1.0
 	gopkg.in/yaml.v2 v2.2.2