package dns import ( "context" "github.com/xtls/xray-core/common/errors" "github.com/xtls/xray-core/common/net" "github.com/xtls/xray-core/common/strmatcher" "github.com/xtls/xray-core/features/dns" ) // StaticHosts represents static domain-ip mapping in DNS server. type StaticHosts struct { ips [][]net.Address matchers *strmatcher.MatcherGroup } // NewStaticHosts creates a new StaticHosts instance. func NewStaticHosts(hosts []*Config_HostMapping) (*StaticHosts, error) { g := new(strmatcher.MatcherGroup) sh := &StaticHosts{ ips: make([][]net.Address, len(hosts)+16), matchers: g, } for _, mapping := range hosts { matcher, err := toStrMatcher(mapping.Type, mapping.Domain) if err != nil { return nil, errors.New("failed to create domain matcher").Base(err) } id := g.Add(matcher) ips := make([]net.Address, 0, len(mapping.Ip)+1) switch { case len(mapping.ProxiedDomain) > 0: ips = append(ips, net.DomainAddress(mapping.ProxiedDomain)) case len(mapping.Ip) > 0: for _, ip := range mapping.Ip { addr := net.IPAddress(ip) if addr == nil { return nil, errors.New("invalid IP address in static hosts: ", ip).AtWarning() } ips = append(ips, addr) } default: return nil, errors.New("neither IP address nor proxied domain specified for domain: ", mapping.Domain).AtWarning() } sh.ips[id] = ips } return sh, nil } func filterIP(ips []net.Address, option dns.IPOption) []net.Address { filtered := make([]net.Address, 0, len(ips)) for _, ip := range ips { if (ip.Family().IsIPv4() && option.IPv4Enable) || (ip.Family().IsIPv6() && option.IPv6Enable) { filtered = append(filtered, ip) } } return filtered } func (h *StaticHosts) lookupInternal(domain string) []net.Address { var ips []net.Address for _, id := range h.matchers.Match(domain) { ips = append(ips, h.ips[id]...) } return ips } func (h *StaticHosts) lookup(domain string, option dns.IPOption, maxDepth int) []net.Address { switch addrs := h.lookupInternal(domain); { case len(addrs) == 0: // Not recorded in static hosts, return nil return nil case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Try to unwrap domain errors.LogDebug(context.Background(), "found replaced domain: ", domain, " -> ", addrs[0].Domain(), ". Try to unwrap it") if maxDepth > 0 { unwrapped := h.lookup(addrs[0].Domain(), option, maxDepth-1) if unwrapped != nil { return unwrapped } } return addrs default: // IP record found, return a non-nil IP array return filterIP(addrs, option) } } // Lookup returns IP addresses or proxied domain for the given domain, if exists in this StaticHosts. func (h *StaticHosts) Lookup(domain string, option dns.IPOption) []net.Address { return h.lookup(domain, option, 5) }