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v2fly/app/dns/dns.go

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//go:build !confonly
// +build !confonly
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// Package dns is an implementation of core.DNS feature.
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package dns
//go:generate go run github.com/v2fly/v2ray-core/v5/common/errors/errorgen
import (
"context"
"fmt"
"strings"
"sync"
core "github.com/v2fly/v2ray-core/v5"
"github.com/v2fly/v2ray-core/v5/app/dns/fakedns"
"github.com/v2fly/v2ray-core/v5/app/router"
"github.com/v2fly/v2ray-core/v5/common"
"github.com/v2fly/v2ray-core/v5/common/errors"
"github.com/v2fly/v2ray-core/v5/common/net"
"github.com/v2fly/v2ray-core/v5/common/platform"
"github.com/v2fly/v2ray-core/v5/common/session"
"github.com/v2fly/v2ray-core/v5/common/strmatcher"
"github.com/v2fly/v2ray-core/v5/features"
"github.com/v2fly/v2ray-core/v5/features/dns"
"github.com/v2fly/v2ray-core/v5/infra/conf/cfgcommon"
"github.com/v2fly/v2ray-core/v5/infra/conf/geodata"
)
// DNS is a DNS rely server.
type DNS struct {
sync.Mutex
hosts *StaticHosts
clients []*Client
ctx context.Context
clientTags map[string]bool
fakeDNSEngine *FakeDNSEngine
domainMatcher strmatcher.IndexMatcher
matcherInfos []DomainMatcherInfo
}
// DomainMatcherInfo contains information attached to index returned by Server.domainMatcher
type DomainMatcherInfo struct {
clientIdx uint16
domainRuleIdx uint16
}
// New creates a new DNS server with given configuration.
func New(ctx context.Context, config *Config) (*DNS, error) {
// Create static hosts
hosts, err := NewStaticHosts(config.StaticHosts, config.Hosts)
if err != nil {
return nil, newError("failed to create hosts").Base(err)
}
// Create name servers from legacy configs
clients := []*Client{}
for _, endpoint := range config.NameServers {
features.PrintDeprecatedFeatureWarning("simple DNS server")
client, err := NewClient(ctx, &NameServer{Address: endpoint}, config)
if err != nil {
return nil, newError("failed to create client").Base(err)
}
clients = append(clients, client)
}
// Create name servers
nsClientMap := map[int]int{}
for nsIdx, ns := range config.NameServer {
client, err := NewClient(ctx, ns, config)
if err != nil {
return nil, newError("failed to create client").Base(err)
}
nsClientMap[nsIdx] = len(clients)
clients = append(clients, client)
}
// If there is no DNS client in config, add a `localhost` DNS client
if len(clients) == 0 {
clients = append(clients, NewLocalDNSClient())
}
s := &DNS{
hosts: hosts,
clients: clients,
ctx: ctx,
}
// Establish members related to global DNS state
s.clientTags = make(map[string]bool)
for _, client := range clients {
s.clientTags[client.tag] = true
}
if err := establishDomainRules(s, config, nsClientMap); err != nil {
return nil, err
}
if err := establishExpectedIPs(s, config, nsClientMap); err != nil {
return nil, err
}
if err := establishFakeDNS(s, config, nsClientMap); err != nil {
return nil, err
}
return s, nil
}
func establishDomainRules(s *DNS, config *Config, nsClientMap map[int]int) error {
domainRuleCount := 0
for _, ns := range config.NameServer {
domainRuleCount += len(ns.PrioritizedDomain)
}
// MatcherInfos is ensured to cover the maximum index domainMatcher could return, where matcher's index starts from 1
matcherInfos := make([]DomainMatcherInfo, domainRuleCount+1)
var domainMatcher strmatcher.IndexMatcher
switch config.DomainMatcher {
case "mph", "hybrid":
newError("using mph domain matcher").AtDebug().WriteToLog()
domainMatcher = strmatcher.NewMphIndexMatcher()
case "linear":
fallthrough
default:
newError("using default domain matcher").AtDebug().WriteToLog()
domainMatcher = strmatcher.NewLinearIndexMatcher()
}
for nsIdx, ns := range config.NameServer {
clientIdx := nsClientMap[nsIdx]
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++
}
midx := domainMatcher.Add(domainRule)
matcherInfos[midx] = DomainMatcherInfo{
clientIdx: uint16(clientIdx),
domainRuleIdx: uint16(originalRuleIdx),
}
if err != nil {
return newError("failed to create prioritized domain").Base(err).AtWarning()
}
}
s.clients[clientIdx].domains = rules
}
if err := domainMatcher.Build(); err != nil {
return err
}
s.domainMatcher = domainMatcher
s.matcherInfos = matcherInfos
return nil
}
func establishExpectedIPs(s *DNS, config *Config, nsClientMap map[int]int) error {
geoipContainer := router.GeoIPMatcherContainer{}
for nsIdx, ns := range config.NameServer {
clientIdx := nsClientMap[nsIdx]
var matchers []*router.GeoIPMatcher
for _, geoip := range ns.Geoip {
matcher, err := geoipContainer.Add(geoip)
if err != nil {
return newError("failed to create ip matcher").Base(err).AtWarning()
}
matchers = append(matchers, matcher)
}
s.clients[clientIdx].expectIPs = matchers
}
return nil
}
func establishFakeDNS(s *DNS, config *Config, nsClientMap map[int]int) error {
fakeHolders := &fakedns.HolderMulti{}
fakeDefault := (*fakedns.HolderMulti)(nil)
if config.FakeDns != nil {
defaultEngine, err := fakeHolders.AddPoolMulti(config.FakeDns)
if err != nil {
return newError("fail to create fake dns").Base(err).AtWarning()
}
fakeDefault = defaultEngine
}
for nsIdx, ns := range config.NameServer {
clientIdx := nsClientMap[nsIdx]
if ns.FakeDns == nil {
continue
}
engine, err := fakeHolders.AddPoolMulti(ns.FakeDns)
if err != nil {
return newError("fail to create fake dns").Base(err).AtWarning()
}
s.clients[clientIdx].fakeDNS = NewFakeDNSServer(engine)
s.clients[clientIdx].queryStrategy.FakeEnable = true
}
// Do not create FakeDNSEngine feature if no FakeDNS server is configured
if fakeHolders.IsEmpty() {
return nil
}
// Add FakeDNSEngine feature when DNS feature is added for the first time
s.fakeDNSEngine = &FakeDNSEngine{dns: s, fakeHolders: fakeHolders, fakeDefault: fakeDefault}
return core.RequireFeatures(s.ctx, func(client dns.Client) error {
v := core.MustFromContext(s.ctx)
if v.GetFeature(dns.FakeDNSEngineType()) != nil {
return nil
}
if client, ok := client.(dns.ClientWithFakeDNS); ok {
return v.AddFeature(client.AsFakeDNSEngine())
}
return nil
})
}
// Type implements common.HasType.
func (*DNS) Type() interface{} {
return dns.ClientType()
}
// Start implements common.Runnable.
func (s *DNS) Start() error {
return nil
}
// Close implements common.Closable.
func (s *DNS) Close() error {
return nil
}
// IsOwnLink implements proxy.dns.ownLinkVerifier
func (s *DNS) IsOwnLink(ctx context.Context) bool {
inbound := session.InboundFromContext(ctx)
return inbound != nil && s.clientTags[inbound.Tag]
}
// AsFakeDNSClient implements dns.ClientWithFakeDNS.
func (s *DNS) AsFakeDNSClient() dns.Client {
return &FakeDNSClient{DNS: s}
}
// AsFakeDNSEngine implements dns.ClientWithFakeDNS.
func (s *DNS) AsFakeDNSEngine() dns.FakeDNSEngine {
return s.fakeDNSEngine
}
// LookupIP implements dns.Client.
func (s *DNS) LookupIP(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{IPv4Enable: true, IPv6Enable: true, FakeEnable: false})
}
// LookupIPv4 implements dns.IPv4Lookup.
func (s *DNS) LookupIPv4(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{IPv4Enable: true, FakeEnable: false})
}
// LookupIPv6 implements dns.IPv6Lookup.
func (s *DNS) LookupIPv6(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{IPv6Enable: true, FakeEnable: false})
}
func (s *DNS) lookupIPInternal(domain string, option dns.IPOption) ([]net.IP, error) {
if domain == "" {
return nil, newError("empty domain name")
}
// Normalize the FQDN form query
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domain = strings.TrimSuffix(domain, ".")
// Static host lookup
switch addrs := s.hosts.Lookup(domain, option); {
case addrs == nil: // Domain not recorded in static host
break
case len(addrs) == 0: // Domain recorded, but no valid IP returned (e.g. IPv4 address with only IPv6 enabled)
return nil, dns.ErrEmptyResponse
case len(addrs) == 1 && addrs[0].Family().IsDomain(): // Domain replacement
newError("domain replaced: ", domain, " -> ", addrs[0].Domain()).WriteToLog()
domain = addrs[0].Domain()
default: // Successfully found ip records in static host
newError("returning ", len(addrs), " IP(s) for domain ", domain, " -> ", addrs).WriteToLog()
return toNetIP(addrs)
}
// Name servers lookup
errs := []error{}
for _, client := range s.sortClients(domain, option) {
ips, err := client.QueryIP(s.ctx, domain, option)
if len(ips) > 0 {
return ips, nil
}
if err != nil {
errs = append(errs, err)
}
if err != dns.ErrEmptyResponse { // ErrEmptyResponse is not seen as failure, so no failed log
newError("failed to lookup ip for domain ", domain, " at server ", client.Name()).Base(err).WriteToLog()
}
if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch {
return nil, err // Only continue lookup for certain errors
}
}
if len(errs) == 0 {
return nil, dns.ErrEmptyResponse
}
return nil, newError("returning nil for domain ", domain).Base(errors.Combine(errs...))
}
func (s *DNS) sortClients(domain string, option dns.IPOption) []*Client {
clients := make([]*Client, 0, len(s.clients))
clientUsed := make([]bool, len(s.clients))
clientIdxs := make([]int, 0, len(s.clients))
domainRules := []string{}
// Priority domain matching
for _, match := range s.domainMatcher.Match(domain) {
info := s.matcherInfos[match]
client := s.clients[info.clientIdx]
domainRule := client.domains[info.domainRuleIdx]
domainRules = append(domainRules, fmt.Sprintf("%s(DNS idx:%d)", domainRule, info.clientIdx))
switch {
case clientUsed[info.clientIdx]:
continue
case !option.FakeEnable && isFakeDNS(client.server):
continue
}
clientUsed[info.clientIdx] = true
clients = append(clients, client)
clientIdxs = append(clientIdxs, int(info.clientIdx))
}
// Default round-robin query
hasDomainMatch := len(clients) > 0
for idx, client := range s.clients {
switch {
case clientUsed[idx]:
continue
case !option.FakeEnable && isFakeDNS(client.server):
continue
case client.fallbackStrategy == FallbackStrategy_Disabled:
continue
case client.fallbackStrategy == FallbackStrategy_DisabledIfAnyMatch && hasDomainMatch:
continue
}
clientUsed[idx] = true
clients = append(clients, client)
clientIdxs = append(clientIdxs, idx)
}
if len(domainRules) > 0 {
newError("domain ", domain, " matches following rules: ", domainRules).AtDebug().WriteToLog()
}
if len(clientIdxs) > 0 {
newError("domain ", domain, " will use DNS in order: ", s.formatClientNames(clientIdxs, option), " ", toReqTypes(option)).AtDebug().WriteToLog()
}
return clients
}
func (s *DNS) formatClientNames(clientIdxs []int, option dns.IPOption) []string {
clientNames := make([]string, 0, len(clientIdxs))
counter := make(map[string]uint, len(clientIdxs))
for _, clientIdx := range clientIdxs {
client := s.clients[clientIdx]
var name string
if option.With(client.queryStrategy).FakeEnable {
name = fmt.Sprintf("%s(DNS idx:%d)", client.fakeDNS.Name(), clientIdx)
} else {
name = client.Name()
}
counter[name]++
clientNames = append(clientNames, name)
}
for idx, clientIdx := range clientIdxs {
name := clientNames[idx]
if counter[name] > 1 {
clientNames[idx] = fmt.Sprintf("%s(DNS idx:%d)", name, clientIdx)
}
}
return clientNames
}
func init() {
common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
return New(ctx, config.(*Config))
}))
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common.Must(common.RegisterConfig((*SimplifiedConfig)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
ctx = cfgcommon.NewConfigureLoadingContext(ctx)
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geoloadername := platform.NewEnvFlag("v2ray.conf.geoloader").GetValue(func() string {
return "standard"
})
if loader, err := geodata.GetGeoDataLoader(geoloadername); err == nil {
cfgcommon.SetGeoDataLoader(ctx, loader)
} else {
return nil, newError("unable to create geo data loader ").Base(err)
}
cfgEnv := cfgcommon.GetConfigureLoadingEnvironment(ctx)
geoLoader := cfgEnv.GetGeoLoader()
simplifiedConfig := config.(*SimplifiedConfig)
for _, v := range simplifiedConfig.NameServer {
for _, geo := range v.Geoip {
if geo.Code != "" {
filepath := "geoip.dat"
if geo.FilePath != "" {
filepath = geo.FilePath
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} else {
geo.CountryCode = geo.Code
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}
var err error
geo.Cidr, err = geoLoader.LoadIP(filepath, geo.Code)
if err != nil {
return nil, newError("unable to load geoip").Base(err)
}
}
}
}
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var nameservers []*NameServer
for _, v := range simplifiedConfig.NameServer {
nameserver := &NameServer{
Address: v.Address,
ClientIp: net.ParseIP(v.ClientIp),
Tag: v.Tag,
QueryStrategy: v.QueryStrategy,
CacheStrategy: v.CacheStrategy,
FallbackStrategy: v.FallbackStrategy,
SkipFallback: v.SkipFallback,
Geoip: v.Geoip,
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}
for _, prioritizedDomain := range v.PrioritizedDomain {
nameserver.PrioritizedDomain = append(nameserver.PrioritizedDomain, &NameServer_PriorityDomain{
Type: prioritizedDomain.Type,
Domain: prioritizedDomain.Domain,
})
}
nameservers = append(nameservers, nameserver)
}
var statichosts []*HostMapping
for _, v := range simplifiedConfig.StaticHosts {
statichost := &HostMapping{
Type: v.Type,
Domain: v.Domain,
ProxiedDomain: v.ProxiedDomain,
}
for _, ip := range v.Ip {
statichost.Ip = append(statichost.Ip, net.ParseIP(ip))
}
statichosts = append(statichosts, statichost)
}
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fullConfig := &Config{
StaticHosts: statichosts,
NameServer: nameservers,
ClientIp: net.ParseIP(simplifiedConfig.ClientIp),
Tag: simplifiedConfig.Tag,
DomainMatcher: simplifiedConfig.DomainMatcher,
QueryStrategy: simplifiedConfig.QueryStrategy,
CacheStrategy: simplifiedConfig.CacheStrategy,
FallbackStrategy: simplifiedConfig.FallbackStrategy,
// Deprecated flags
DisableCache: simplifiedConfig.DisableCache,
DisableFallback: simplifiedConfig.DisableFallback,
DisableFallbackIfMatch: simplifiedConfig.DisableFallbackIfMatch,
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}
return common.CreateObject(ctx, fullConfig)
}))
}