package dns import ( "net" "time" "github.com/v2ray/v2ray-core/app" "github.com/v2ray/v2ray-core/common/collect" "github.com/v2ray/v2ray-core/common/serial" ) type entry struct { domain string ip net.IP validUntil time.Time } func newEntry(domain string, ip net.IP) *entry { this := &entry{ domain: domain, ip: ip, } this.Extend() return this } func (this *entry) IsValid() bool { return this.validUntil.After(time.Now()) } func (this *entry) Extend() { this.validUntil = time.Now().Add(time.Hour) } type DnsCache struct { cache *collect.ValidityMap config CacheConfig } func NewCache(config CacheConfig) *DnsCache { cache := &DnsCache{ cache: collect.NewValidityMap(3600), config: config, } return cache } func (this *DnsCache) Add(context app.Context, domain string, ip net.IP) { callerTag := context.CallerTag() if !this.config.IsTrustedSource(callerTag) { return } this.cache.Set(serial.StringLiteral(domain), newEntry(domain, ip)) } func (this *DnsCache) Get(context app.Context, domain string) net.IP { if value := this.cache.Get(serial.StringLiteral(domain)); value != nil { return value.(*entry).ip } return nil }