Xray-core/app/dns/nameserver.go
2025-04-29 14:15:43 +03:30

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package dns
import (
"context"
"net/url"
"strings"
"time"
"github.com/xtls/xray-core/app/router"
"github.com/xtls/xray-core/common/errors"
"github.com/xtls/xray-core/common/net"
"github.com/xtls/xray-core/common/session"
"github.com/xtls/xray-core/common/strmatcher"
"github.com/xtls/xray-core/core"
"github.com/xtls/xray-core/features/dns"
"github.com/xtls/xray-core/features/routing"
)
// Server is the interface for Name Server.
type Server interface {
// Name of the Client.
Name() string
// QueryIP sends IP queries to its configured server.
QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, uint32, error)
}
// Client is the interface for DNS client.
type Client struct {
server Server
skipFallback bool
domains []string
expectedIPs []*router.GeoIPMatcher
unexpectedIPs []*router.GeoIPMatcher
priorIPs []*router.GeoIPMatcher
unpriorIPs []*router.GeoIPMatcher
tag string
timeoutMs time.Duration
finalQuery bool
ipOption *dns.IPOption
}
// NewServer creates a name server object according to the network destination url.
func NewServer(ctx context.Context, dest net.Destination, dispatcher routing.Dispatcher, disableCache bool, clientIP net.IP) (Server, error) {
if address := dest.Address; address.Family().IsDomain() {
u, err := url.Parse(address.Domain())
if err != nil {
return nil, err
}
switch {
case strings.EqualFold(u.String(), "localhost"):
return NewLocalNameServer(), nil
case strings.EqualFold(u.Scheme, "https"): // DNS-over-HTTPS Remote mode
return NewDoHNameServer(u, dispatcher, false, disableCache, clientIP), nil
case strings.EqualFold(u.Scheme, "h2c"): // DNS-over-HTTPS h2c Remote mode
return NewDoHNameServer(u, dispatcher, true, disableCache, clientIP), nil
case strings.EqualFold(u.Scheme, "https+local"): // DNS-over-HTTPS Local mode
return NewDoHNameServer(u, nil, false, disableCache, clientIP), nil
case strings.EqualFold(u.Scheme, "h2c+local"): // DNS-over-HTTPS h2c Local mode
return NewDoHNameServer(u, nil, true, disableCache, clientIP), nil
case strings.EqualFold(u.Scheme, "quic+local"): // DNS-over-QUIC Local mode
return NewQUICNameServer(u, disableCache, clientIP)
case strings.EqualFold(u.Scheme, "tcp"): // DNS-over-TCP Remote mode
return NewTCPNameServer(u, dispatcher, disableCache, clientIP)
case strings.EqualFold(u.Scheme, "tcp+local"): // DNS-over-TCP Local mode
return NewTCPLocalNameServer(u, disableCache, clientIP)
case strings.EqualFold(u.String(), "fakedns"):
var fd dns.FakeDNSEngine
err = core.RequireFeatures(ctx, func(fdns dns.FakeDNSEngine) {
fd = fdns
})
if err != nil {
return nil, err
}
return NewFakeDNSServer(fd), nil
}
}
if dest.Network == net.Network_Unknown {
dest.Network = net.Network_UDP
}
if dest.Network == net.Network_UDP { // UDP classic DNS mode
return NewClassicNameServer(dest, dispatcher, disableCache, clientIP), nil
}
return nil, errors.New("No available name server could be created from ", dest).AtWarning()
}
// NewClient creates a DNS client managing a name server with client IP, domain rules and expected IPs.
func NewClient(
ctx context.Context,
ns *NameServer,
clientIP net.IP,
disableCache bool,
tag string,
ipOption dns.IPOption,
matcherInfos *[]*DomainMatcherInfo,
updateDomainRule func(strmatcher.Matcher, int, []*DomainMatcherInfo) error,
) (*Client, error) {
client := &Client{}
err := core.RequireFeatures(ctx, func(dispatcher routing.Dispatcher) error {
// Create a new server for each client for now
server, err := NewServer(ctx, ns.Address.AsDestination(), dispatcher, disableCache, clientIP)
if err != nil {
return errors.New("failed to create nameserver").Base(err).AtWarning()
}
// Prioritize local domains with specific TLDs or those without any dot for the local DNS
if _, isLocalDNS := server.(*LocalNameServer); isLocalDNS {
ns.PrioritizedDomain = append(ns.PrioritizedDomain, localTLDsAndDotlessDomains...)
ns.OriginalRules = append(ns.OriginalRules, localTLDsAndDotlessDomainsRule)
// The following lines is a solution to avoid core panicsrule index out of range when setting `localhost` DNS client in config.
// Because the `localhost` DNS client will append len(localTLDsAndDotlessDomains) rules into matcherInfos to match `geosite:private` default rule.
// But `matcherInfos` has no enough length to add rules, which leads to core panics (rule index out of range).
// To avoid this, the length of `matcherInfos` must be equal to the expected, so manually append it with Golang default zero value first for later modification.
// Related issues:
// https://github.com/v2fly/v2ray-core/issues/529
// https://github.com/v2fly/v2ray-core/issues/719
for i := 0; i < len(localTLDsAndDotlessDomains); i++ {
*matcherInfos = append(*matcherInfos, &DomainMatcherInfo{
clientIdx: uint16(0),
domainRuleIdx: uint16(0),
})
}
}
// Establish domain rules
var rules []string
ruleCurr := 0
ruleIter := 0
for _, domain := range ns.PrioritizedDomain {
domainRule, err := toStrMatcher(domain.Type, domain.Domain)
if err != nil {
return errors.New("failed to create prioritized domain").Base(err).AtWarning()
}
originalRuleIdx := ruleCurr
if ruleCurr < len(ns.OriginalRules) {
rule := ns.OriginalRules[ruleCurr]
if ruleCurr >= len(rules) {
rules = append(rules, rule.Rule)
}
ruleIter++
if ruleIter >= int(rule.Size) {
ruleIter = 0
ruleCurr++
}
} else { // No original rule, generate one according to current domain matcher (majorly for compatibility with tests)
rules = append(rules, domainRule.String())
ruleCurr++
}
err = updateDomainRule(domainRule, originalRuleIdx, *matcherInfos)
if err != nil {
return errors.New("failed to create prioritized domain").Base(err).AtWarning()
}
}
// Establish expected IPs
var expectedMatchers []*router.GeoIPMatcher
for _, geoip := range ns.ExpectedGeoip {
matcher, err := router.GlobalGeoIPContainer.Add(geoip)
if err != nil {
return errors.New("failed to create expected ip matcher").Base(err).AtWarning()
}
expectedMatchers = append(expectedMatchers, matcher)
}
// Establish unexpected IPs
var unexpectedMatchers []*router.GeoIPMatcher
for _, geoip := range ns.UnexpectedGeoip {
matcher, err := router.GlobalGeoIPContainer.Add(geoip)
if err != nil {
return errors.New("failed to create unexpected ip matcher").Base(err).AtWarning()
}
unexpectedMatchers = append(unexpectedMatchers, matcher)
}
// Establish prior IPs
var priorMatchers []*router.GeoIPMatcher
for _, geoip := range ns.PriorGeoip {
matcher, err := router.GlobalGeoIPContainer.Add(geoip)
if err != nil {
return errors.New("failed to create prior ip matcher").Base(err).AtWarning()
}
priorMatchers = append(priorMatchers, matcher)
}
// Establish unprior IPs
var unpriorMatchers []*router.GeoIPMatcher
for _, geoip := range ns.UnpriorGeoip {
matcher, err := router.GlobalGeoIPContainer.Add(geoip)
if err != nil {
return errors.New("failed to create unprior ip matcher").Base(err).AtWarning()
}
unpriorMatchers = append(unpriorMatchers, matcher)
}
if len(clientIP) > 0 {
switch ns.Address.Address.GetAddress().(type) {
case *net.IPOrDomain_Domain:
errors.LogInfo(ctx, "DNS: client ", ns.Address.Address.GetDomain(), " uses clientIP ", clientIP.String())
case *net.IPOrDomain_Ip:
errors.LogInfo(ctx, "DNS: client ", net.IP(ns.Address.Address.GetIp()), " uses clientIP ", clientIP.String())
}
}
var timeoutMs = 4000 * time.Millisecond
if ns.TimeoutMs > 0 {
timeoutMs = time.Duration(ns.TimeoutMs) * time.Millisecond
}
client.server = server
client.skipFallback = ns.SkipFallback
client.domains = rules
client.expectedIPs = expectedMatchers
client.unexpectedIPs = unexpectedMatchers
client.priorIPs = priorMatchers
client.unpriorIPs = unpriorMatchers
client.tag = tag
client.timeoutMs = timeoutMs
client.finalQuery = ns.FinalQuery
client.ipOption = &ipOption
return nil
})
return client, err
}
// Name returns the server name the client manages.
func (c *Client) Name() string {
return c.server.Name()
}
func (c *Client) IsFinalQuery() bool {
return c.finalQuery
}
// QueryIP sends DNS query to the name server with the client's IP.
func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption) ([]net.IP, uint32, error) {
option.IPv4Enable = option.IPv4Enable && c.ipOption.IPv4Enable
option.IPv6Enable = option.IPv6Enable && c.ipOption.IPv6Enable
if !option.IPv4Enable && !option.IPv6Enable {
return nil, 0, dns.ErrEmptyResponse
}
ctx, cancel := context.WithTimeout(ctx, c.timeoutMs)
ctx = session.ContextWithInbound(ctx, &session.Inbound{Tag: c.tag})
ips, ttl, err := c.server.QueryIP(ctx, domain, option)
cancel()
if err != nil {
return nil, 0, err
}
if len(ips) == 0 {
return nil, 0, dns.ErrEmptyResponse
}
if len(c.expectedIPs) > 0 {
ips = router.MatchIPs(c.expectedIPs, ips, false)
errors.LogDebug(context.Background(), "domain ", domain, " expectedIPs ", ips, " matched at server ", c.Name())
if len(ips) == 0 {
return nil, 0, dns.ErrEmptyResponse
}
}
if len(c.unexpectedIPs) > 0 {
ips = router.MatchIPs(c.unexpectedIPs, ips, true)
errors.LogDebug(context.Background(), "domain ", domain, " unexpectedIPs ", ips, " matched at server ", c.Name())
if len(ips) == 0 {
return nil, 0, dns.ErrEmptyResponse
}
}
if len(c.priorIPs) > 0 {
ipsNew := router.MatchIPs(c.priorIPs, ips, false)
if len(ipsNew) > 0 {
ips = ipsNew
errors.LogDebug(context.Background(), "domain ", domain, " priorIPs ", ips, " matched at server ", c.Name())
}
}
if len(c.unpriorIPs) > 0 {
ipsNew := router.MatchIPs(c.unpriorIPs, ips, true)
if len(ipsNew) > 0 {
ips = ipsNew
errors.LogDebug(context.Background(), "domain ", domain, " unpriorIPs ", ips, " matched at server ", c.Name())
}
}
return ips, ttl, nil
}
func ResolveIpOptionOverride(queryStrategy QueryStrategy, ipOption dns.IPOption) dns.IPOption {
switch queryStrategy {
case QueryStrategy_USE_IP:
return ipOption
case QueryStrategy_USE_IP4:
return dns.IPOption{
IPv4Enable: ipOption.IPv4Enable,
IPv6Enable: false,
FakeEnable: false,
}
case QueryStrategy_USE_IP6:
return dns.IPOption{
IPv4Enable: false,
IPv6Enable: ipOption.IPv6Enable,
FakeEnable: false,
}
default:
return ipOption
}
}