mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-12-22 18:17:52 -05:00
98 lines
1.6 KiB
Go
98 lines
1.6 KiB
Go
package dns
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import (
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"net"
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"sync"
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"time"
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"github.com/v2ray/v2ray-core/app"
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)
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type entry struct {
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domain string
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ip net.IP
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validUntil time.Time
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}
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func newEntry(domain string, ip net.IP) *entry {
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this := &entry{
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domain: domain,
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ip: ip,
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}
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this.Extend()
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return this
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}
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func (this *entry) IsValid() bool {
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return this.validUntil.After(time.Now())
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}
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func (this *entry) Extend() {
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this.validUntil = time.Now().Add(time.Hour)
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}
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type DnsCache struct {
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sync.RWMutex
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cache map[string]*entry
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config CacheConfig
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}
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func NewCache(config CacheConfig) *DnsCache {
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cache := &DnsCache{
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cache: make(map[string]*entry),
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config: config,
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}
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go cache.cleanup()
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return cache
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}
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func (this *DnsCache) cleanup() {
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for range time.Tick(60 * time.Second) {
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entry2Remove := make([]*entry, 0, 128)
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this.RLock()
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for _, entry := range this.cache {
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if !entry.IsValid() {
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entry2Remove = append(entry2Remove, entry)
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}
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}
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this.RUnlock()
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for _, entry := range entry2Remove {
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if !entry.IsValid() {
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this.Lock()
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delete(this.cache, entry.domain)
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this.Unlock()
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}
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}
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}
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}
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func (this *DnsCache) Add(context app.Context, domain string, ip net.IP) {
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callerTag := context.CallerTag()
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if !this.config.IsTrustedSource(callerTag) {
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return
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}
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this.RLock()
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entry, found := this.cache[domain]
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this.RUnlock()
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if found {
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entry.ip = ip
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entry.Extend()
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} else {
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this.Lock()
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this.cache[domain] = newEntry(domain, ip)
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this.Unlock()
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}
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}
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func (this *DnsCache) Get(context app.Context, domain string) net.IP {
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this.RLock()
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entry, found := this.cache[domain]
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this.RUnlock()
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if found {
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return entry.ip
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}
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return nil
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}
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