cache

Documentation

Index

• func Key(q dns.Question, dnssec, tcp bool) string
• func KeyRRset(rrs []dns.RR) string
• type Cache
  • func New(capacity, ttl int) *Cache
  • func (c *Cache) Capacity() int
  • func (c *Cache) EvictRandom()
  • func (c *Cache) Hit(question dns.Question, dnssec, tcp bool, msgid uint16) (m1 *dns.Msg, expired bool, key string)
  • func (c *Cache) InsertMessage(s string, msg *dns.Msg)
  • func (c *Cache) Remove(s string)
  • func (c *Cache) Search(s string) (*dns.Msg, time.Time, bool)

Functions

func Key

func Key(q dns.Question, dnssec, tcp bool) string

Key creates a hash key from a question section. It creates a different key for requests with DNSSEC.

func KeyRRset

func KeyRRset(rrs []dns.RR) string

Key uses the name, type and rdata, which is serialized and then hashed as the key for the lookup.

Types

type Cache

type Cache struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

Cache is a cache that holds on the a number of RRs or DNS messages. The cache eviction is randomized.

func New

func New(capacity, ttl int) *Cache

New returns a new cache with the capacity and the ttl specified.

func (*Cache) Capacity

func (c *Cache) Capacity() int

func (*Cache) EvictRandom

func (c *Cache) EvictRandom()

EvictRandom removes a random member a the cache. Must be called under a write lock.

func (*Cache) Hit

func (c *Cache) Hit(question dns.Question, dnssec, tcp bool, msgid uint16) (m1 *dns.Msg, expired bool, key string)

Hit returns a dns message, expired bool, and key from the cache. The caller must decide whether or not to remove the cache entry if expired.

func (*Cache) InsertMessage

func (c *Cache) InsertMessage(s string, msg *dns.Msg)

InsertMessage inserts a message in the Cache. We will cache it for ttl seconds, which should be a small (60...300) integer.

func (*Cache) Remove

func (c *Cache) Remove(s string)

func (*Cache) Search

func (c *Cache) Search(s string) (*dns.Msg, time.Time, bool)

Search returns a dns.Msg, the expiration time and a boolean indicating if we found something in the cache.