Xray-core/app/dns/nameserver.go

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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/strmatcher"
core "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, clientIP net.IP, option dns.IPOption, cs CacheStrategy) ([]net.IP, error)
}
// Client is the interface for DNS client.
type Client struct {
server Server
clientIP net.IP
skipFallback bool
domains []string
expectIPs []*router.GeoIPMatcher
}
var errExpectedIPNonMatch = errors.New("expectIPs not match")
// NewServer creates a name server object according to the network destination url.
func NewServer(dest net.Destination, dispatcher routing.Dispatcher) (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"): // DOH Remote mode
return NewDoHNameServer(u, dispatcher)
case strings.EqualFold(u.Scheme, "https+local"): // DOH Local mode
return NewDoHLocalNameServer(u), nil
case strings.EqualFold(u.Scheme, "quic+local"): // DNS-over-QUIC Local mode
return NewQUICNameServer(u)
case strings.EqualFold(u.String(), "fakedns"):
return NewFakeDNSServer(), 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), nil
}
return nil, newError("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, container router.GeoIPMatcherContainer, 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(ns.Address.AsDestination(), dispatcher)
if err != nil {
return newError("failed to create nameserver").Base(err).AtWarning()
}
// Priotize local domains with specific TLDs or without any dot to 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 apend 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.
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 newError("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 newError("failed to create prioritized domain").Base(err).AtWarning()
}
}
// Establish expected IPs
var matchers []*router.GeoIPMatcher
for _, geoip := range ns.Geoip {
matcher, err := container.Add(geoip)
if err != nil {
return newError("failed to create ip matcher").Base(err).AtWarning()
}
matchers = append(matchers, matcher)
}
if len(clientIP) > 0 {
switch ns.Address.Address.GetAddress().(type) {
case *net.IPOrDomain_Domain:
newError("DNS: client ", ns.Address.Address.GetDomain(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
case *net.IPOrDomain_Ip:
newError("DNS: client ", ns.Address.Address.GetIp(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
}
}
client.server = server
client.clientIP = clientIP
client.domains = rules
client.expectIPs = matchers
return nil
})
return client, err
}
// NewSimpleClient creates a DNS client with a simple destination.
func NewSimpleClient(ctx context.Context, endpoint *net.Endpoint, clientIP net.IP) (*Client, error) {
client := &Client{}
err := core.RequireFeatures(ctx, func(dispatcher routing.Dispatcher) error {
server, err := NewServer(endpoint.AsDestination(), dispatcher)
if err != nil {
return newError("failed to create nameserver").Base(err).AtWarning()
}
client.server = server
client.clientIP = clientIP
return nil
})
if len(clientIP) > 0 {
switch endpoint.Address.GetAddress().(type) {
case *net.IPOrDomain_Domain:
newError("DNS: client ", endpoint.Address.GetDomain(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
case *net.IPOrDomain_Ip:
newError("DNS: client ", endpoint.Address.GetIp(), " uses clientIP ", clientIP.String()).AtInfo().WriteToLog()
}
}
return client, err
}
// Name returns the server name the client manages.
func (c *Client) Name() string {
return c.server.Name()
}
// QueryIP send DNS query to the name server with the client's IP.
func (c *Client) QueryIP(ctx context.Context, domain string, option dns.IPOption, cs CacheStrategy) ([]net.IP, error) {
ctx, cancel := context.WithTimeout(ctx, 4*time.Second)
ips, err := c.server.QueryIP(ctx, domain, c.clientIP, option, cs)
cancel()
if err != nil {
return ips, err
}
return c.MatchExpectedIPs(domain, ips)
}
// MatchExpectedIPs matches queried domain IPs with expected IPs and returns matched ones.
func (c *Client) MatchExpectedIPs(domain string, ips []net.IP) ([]net.IP, error) {
if len(c.expectIPs) == 0 {
return ips, nil
}
newIps := []net.IP{}
for _, ip := range ips {
for _, matcher := range c.expectIPs {
if matcher.Match(ip) {
newIps = append(newIps, ip)
break
}
}
}
if len(newIps) == 0 {
return nil, errExpectedIPNonMatch
}
newError("domain ", domain, " expectIPs ", newIps, " matched at server ", c.Name()).AtDebug().WriteToLog()
return newIps, nil
}