clash/adapter/outboundgroup/loadbalance.go
2021-06-10 14:05:56 +08:00

179 lines
4 KiB
Go

package outboundgroup
import (
"context"
"encoding/json"
"errors"
"fmt"
"net"
"github.com/Dreamacro/clash/adapter/outbound"
"github.com/Dreamacro/clash/adapter/provider"
"github.com/Dreamacro/clash/common/murmur3"
"github.com/Dreamacro/clash/common/singledo"
C "github.com/Dreamacro/clash/constant"
"golang.org/x/net/publicsuffix"
)
type strategyFn = func(proxies []C.Proxy, metadata *C.Metadata) C.Proxy
type LoadBalance struct {
*outbound.Base
disableUDP bool
single *singledo.Single
providers []provider.ProxyProvider
strategyFn strategyFn
}
var errStrategy = errors.New("unsupported strategy")
func parseStrategy(config map[string]interface{}) string {
if elm, ok := config["strategy"]; ok {
if strategy, ok := elm.(string); ok {
return strategy
}
}
return "consistent-hashing"
}
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.DstIP == nil {
return ""
}
return metadata.DstIP.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)
}
// DialContext implements C.ProxyAdapter
func (lb *LoadBalance) DialContext(ctx context.Context, metadata *C.Metadata) (c C.Conn, err error) {
defer func() {
if err == nil {
c.AppendToChains(lb)
}
}()
proxy := lb.Unwrap(metadata)
c, err = proxy.DialContext(ctx, metadata)
return
}
// DialUDP implements C.ProxyAdapter
func (lb *LoadBalance) DialUDP(metadata *C.Metadata) (pc C.PacketConn, err error) {
defer func() {
if err == nil {
pc.AppendToChains(lb)
}
}()
proxy := lb.Unwrap(metadata)
return proxy.DialUDP(metadata)
}
// SupportUDP implements C.ProxyAdapter
func (lb *LoadBalance) SupportUDP() bool {
return !lb.disableUDP
}
func strategyRoundRobin() strategyFn {
idx := 0
return func(proxies []C.Proxy, metadata *C.Metadata) C.Proxy {
length := len(proxies)
for i := 0; i < length; i++ {
idx = (idx + 1) % length
proxy := proxies[idx]
if proxy.Alive() {
return proxy
}
}
return proxies[0]
}
}
func strategyConsistentHashing() strategyFn {
maxRetry := 5
return func(proxies []C.Proxy, metadata *C.Metadata) C.Proxy {
key := uint64(murmur3.Sum32([]byte(getKey(metadata))))
buckets := int32(len(proxies))
for i := 0; i < maxRetry; i, key = i+1, key+1 {
idx := jumpHash(key, buckets)
proxy := proxies[idx]
if proxy.Alive() {
return proxy
}
}
return proxies[0]
}
}
// Unwrap implements C.ProxyAdapter
func (lb *LoadBalance) Unwrap(metadata *C.Metadata) C.Proxy {
proxies := lb.proxies(true)
return lb.strategyFn(proxies, metadata)
}
func (lb *LoadBalance) proxies(touch bool) []C.Proxy {
elm, _, _ := lb.single.Do(func() (interface{}, error) {
return getProvidersProxies(lb.providers, touch), nil
})
return elm.([]C.Proxy)
}
// MarshalJSON implements C.ProxyAdapter
func (lb *LoadBalance) MarshalJSON() ([]byte, error) {
var all []string
for _, proxy := range lb.proxies(false) {
all = append(all, proxy.Name())
}
return json.Marshal(map[string]interface{}{
"type": lb.Type().String(),
"all": all,
})
}
func NewLoadBalance(options *GroupCommonOption, providers []provider.ProxyProvider, strategy string) (lb *LoadBalance, err error) {
var strategyFn strategyFn
switch strategy {
case "consistent-hashing":
strategyFn = strategyConsistentHashing()
case "round-robin":
strategyFn = strategyRoundRobin()
default:
return nil, fmt.Errorf("%w: %s", errStrategy, strategy)
}
return &LoadBalance{
Base: outbound.NewBase(options.Name, "", C.LoadBalance, false),
single: singledo.NewSingle(defaultGetProxiesDuration),
providers: providers,
strategyFn: strategyFn,
disableUDP: options.DisableUDP,
}, nil
}