package fakeip import ( "errors" "net" "sync" "github.com/Dreamacro/clash/common/cache" "github.com/Dreamacro/clash/component/trie" ) // Pool is a implementation about fake ip generator without storage type Pool struct { max uint32 min uint32 gateway uint32 offset uint32 mux sync.Mutex host *trie.DomainTrie cache *cache.LruCache } // Lookup return a fake ip with host func (p *Pool) Lookup(host string) net.IP { p.mux.Lock() defer p.mux.Unlock() if elm, exist := p.cache.Get(host); exist { ip := elm.(net.IP) // ensure ip --> host on head of linked list n := ipToUint(ip.To4()) offset := n - p.min + 1 p.cache.Get(offset) return ip } ip := p.get(host) p.cache.Set(host, ip) return ip } // LookBack return host with the fake ip func (p *Pool) LookBack(ip net.IP) (string, bool) { p.mux.Lock() defer p.mux.Unlock() if ip = ip.To4(); ip == nil { return "", false } n := ipToUint(ip.To4()) offset := n - p.min + 1 if elm, exist := p.cache.Get(offset); exist { host := elm.(string) // ensure host --> ip on head of linked list p.cache.Get(host) return host, true } return "", false } // LookupHost return if domain in host func (p *Pool) LookupHost(domain string) bool { if p.host == nil { return false } return p.host.Search(domain) != nil } // Exist returns if given ip exists in fake-ip pool func (p *Pool) Exist(ip net.IP) bool { p.mux.Lock() defer p.mux.Unlock() if ip = ip.To4(); ip == nil { return false } n := ipToUint(ip.To4()) offset := n - p.min + 1 return p.cache.Exist(offset) } // Gateway return gateway ip func (p *Pool) Gateway() net.IP { return uintToIP(p.gateway) } // PatchFrom clone cache from old pool func (p *Pool) PatchFrom(o *Pool) { o.cache.CloneTo(p.cache) } func (p *Pool) get(host string) net.IP { current := p.offset for { p.offset = (p.offset + 1) % (p.max - p.min) // Avoid infinite loops if p.offset == current { break } if !p.cache.Exist(p.offset) { break } } ip := uintToIP(p.min + p.offset - 1) p.cache.Set(p.offset, host) return ip } func ipToUint(ip net.IP) uint32 { v := uint32(ip[0]) << 24 v += uint32(ip[1]) << 16 v += uint32(ip[2]) << 8 v += uint32(ip[3]) return v } func uintToIP(v uint32) net.IP { return net.IP{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)} } // New return Pool instance func New(ipnet *net.IPNet, size int, host *trie.DomainTrie) (*Pool, error) { min := ipToUint(ipnet.IP) + 2 ones, bits := ipnet.Mask.Size() total := 1<