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v2fly/app/dns/dns.go

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// +build !confonly
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// Package dns is an implementation of core.DNS feature.
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package dns
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//go:generate go run github.com/v2fly/v2ray-core/v4/common/errors/errorgen
import (
"context"
"fmt"
"strings"
"sync"
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"github.com/v2fly/v2ray-core/v4/app/router"
"github.com/v2fly/v2ray-core/v4/common"
"github.com/v2fly/v2ray-core/v4/common/errors"
"github.com/v2fly/v2ray-core/v4/common/net"
"github.com/v2fly/v2ray-core/v4/common/session"
"github.com/v2fly/v2ray-core/v4/common/strmatcher"
"github.com/v2fly/v2ray-core/v4/features"
"github.com/v2fly/v2ray-core/v4/features/dns"
)
// DNS is a DNS rely server.
type DNS struct {
sync.Mutex
tag string
disableCache bool
disableFallback bool
ipOption *dns.IPOption
hosts *StaticHosts
clients []*Client
ctx context.Context
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) {
var tag string
if len(config.Tag) > 0 {
tag = config.Tag
} else {
tag = generateRandomTag()
}
var clientIP net.IP
switch len(config.ClientIp) {
case 0, net.IPv4len, net.IPv6len:
clientIP = net.IP(config.ClientIp)
default:
return nil, newError("unexpected client IP length ", len(config.ClientIp))
}
var ipOption *dns.IPOption
switch config.QueryStrategy {
case QueryStrategy_USE_IP:
ipOption = &dns.IPOption{
IPv4Enable: true,
IPv6Enable: true,
FakeEnable: false,
}
case QueryStrategy_USE_IP4:
ipOption = &dns.IPOption{
IPv4Enable: true,
IPv6Enable: false,
FakeEnable: false,
}
case QueryStrategy_USE_IP6:
ipOption = &dns.IPOption{
IPv4Enable: false,
IPv6Enable: true,
FakeEnable: false,
}
}
hosts, err := NewStaticHosts(config.StaticHosts, config.Hosts)
if err != nil {
return nil, newError("failed to create hosts").Base(err)
}
clients := []*Client{}
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)
domainMatcher := &strmatcher.MatcherGroup{}
geoipContainer := router.GeoIPMatcherContainer{}
for _, endpoint := range config.NameServers {
features.PrintDeprecatedFeatureWarning("simple DNS server")
client, err := NewSimpleClient(ctx, endpoint, clientIP)
if err != nil {
return nil, newError("failed to create client").Base(err)
}
clients = append(clients, client)
}
for _, ns := range config.NameServer {
clientIdx := len(clients)
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updateDomain := func(domainRule strmatcher.Matcher, originalRuleIdx int, matcherInfos []DomainMatcherInfo) error {
midx := domainMatcher.Add(domainRule)
matcherInfos[midx] = DomainMatcherInfo{
clientIdx: uint16(clientIdx),
domainRuleIdx: uint16(originalRuleIdx),
}
return nil
}
myClientIP := clientIP
switch len(ns.ClientIp) {
case net.IPv4len, net.IPv6len:
myClientIP = net.IP(ns.ClientIp)
}
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client, err := NewClient(ctx, ns, myClientIP, geoipContainer, &matcherInfos, updateDomain)
if err != nil {
return nil, newError("failed to create client").Base(err)
}
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())
}
return &DNS{
tag: tag,
hosts: hosts,
ipOption: ipOption,
clients: clients,
ctx: ctx,
domainMatcher: domainMatcher,
matcherInfos: matcherInfos,
disableCache: config.DisableCache,
disableFallback: config.DisableFallback,
}, 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 && inbound.Tag == s.tag
}
// LookupIP implements dns.Client.
func (s *DNS) LookupIP(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{
IPv4Enable: true,
IPv6Enable: true,
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FakeEnable: s.ipOption.FakeEnable,
})
}
// LookupIPv4 implements dns.IPv4Lookup.
func (s *DNS) LookupIPv4(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{
IPv4Enable: true,
IPv6Enable: false,
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FakeEnable: s.ipOption.FakeEnable,
})
}
// LookupIPv6 implements dns.IPv6Lookup.
func (s *DNS) LookupIPv6(domain string) ([]net.IP, error) {
return s.lookupIPInternal(domain, dns.IPOption{
IPv4Enable: false,
IPv6Enable: true,
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FakeEnable: s.ipOption.FakeEnable,
})
}
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
if strings.HasSuffix(domain, ".") {
domain = domain[:len(domain)-1]
}
// 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), " IPs for domain ", domain).WriteToLog()
return toNetIP(addrs)
}
// Name servers lookup
errs := []error{}
Feature: Fake DNS support (#406) * Add fake dns A new config object "fake" in DnsObject for toggling fake dns function Compare with sniffing, fake dns is not limited to http and tls traffic. It works across all inbounds. For example, when dns request come from one inbound, the local DNS server of v2ray will response with a unique fake IP for every unique domain name. Then later on v2ray received a request to one of the fake IP from any inbounds, it will override the request destination with the previously saved domain. By default, v2ray cache up to 65535 addresses. The old records will be discarded bases on LRU. The fake IP will be 240.x.x.x * fix an edge case when encounter a fake IP in use * Move lru to common.cache package * Added the necessary change to obtain request IP from sniffer * Refactor the code so that it may stop depending on global variables in the future. * Replace string manipulation code with more generic codes, hopefully this will work for both IPv4 and IPv6 networks. * Try to use IPv4 version of address if possible * Added Test Case for Fake Dns * Added More Test Case for Fake Dns * Stop user from creating a instance with LRU size more than subnet size, it will create a infinite loop * Move Fake DNS to a separate package * Generated Code for fakedns * Encapsulate Fake DNS as a Instance wide service * Added Support for metadata sniffer, which will be used for Fake DNS * Dependency injection for fake dns * Fake DNS As a Sniffer * Remove stub object * Remove global variable * Update generated protobuf file for metadata only sniffing * Apply Fake DNS config to session * Loading for fake dns settings * Bug fix * Include fake dns in all * Fix FakeDns Lint Condition * Fix sniffer config * Fix lint message * Fix dependency resolution * Fix fake dns not loaded as sniffer * reduce ttl for fake dns * Apply Coding Style * Apply Coding Style * Apply Coding Style * Apply Coding Style * Apply Coding Style * Fix crashed when no fake dns * Apply Coding Style * Fix Fake DNS do not apply to UDP socket * Fixed a bug prevent FakeDNS App Setting from become effective * Fixed a caveat prevent FakeDNS App Setting from become effective * Use log comparison to reduce in issue when it comes to really high value typical for ipv6 subnet * Add build tag for fakedns * Removal of FakeDNS specific logic at DNS client: making it a standard dns client * Regenerate auto generated file * Amended version of configure file * Bug fixes for fakeDNS * Bug fixes for fakeDNS * Fix test: remove reference to removed attribute * Test: fix codacy issue * Conf: Remove old field support * Test: fix codacy issue * Change test scale for TestFakeDnsHolderCreateMappingAndRollOver * Test: fix codacy issue Co-authored-by: yuhan6665 <1588741+yuhan6665@users.noreply.github.com> Co-authored-by: loyalsoldier <10487845+Loyalsoldier@users.noreply.github.com> Co-authored-by: kslr <kslrwang@gmail.com>
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ctx := session.ContextWithInbound(s.ctx, &session.Inbound{Tag: s.tag})
for _, client := range s.sortClients(domain) {
if !option.FakeEnable && strings.EqualFold(client.Name(), "FakeDNS") {
newError("skip DNS resolution for domain ", domain, " at server ", client.Name()).AtDebug().WriteToLog()
continue
}
ips, err := client.QueryIP(ctx, domain, option, s.disableCache)
if len(ips) > 0 {
return ips, nil
}
if err != nil {
newError("failed to lookup ip for domain ", domain, " at server ", client.Name()).Base(err).WriteToLog()
errs = append(errs, err)
}
if err != context.Canceled && err != context.DeadlineExceeded && err != errExpectedIPNonMatch {
return nil, err
}
}
return nil, newError("returning nil for domain ", domain).Base(errors.Combine(errs...))
}
// GetIPOption implements ClientWithIPOption.
func (s *DNS) GetIPOption() *dns.IPOption {
return s.ipOption
}
// SetQueryOption implements ClientWithIPOption.
func (s *DNS) SetQueryOption(isIPv4Enable, isIPv6Enable bool) {
s.ipOption.IPv4Enable = isIPv4Enable
s.ipOption.IPv6Enable = isIPv6Enable
}
// SetFakeDNSOption implements ClientWithIPOption.
func (s *DNS) SetFakeDNSOption(isFakeEnable bool) {
s.ipOption.FakeEnable = isFakeEnable
}
func (s *DNS) sortClients(domain string) []*Client {
clients := make([]*Client, 0, len(s.clients))
clientUsed := make([]bool, len(s.clients))
clientNames := make([]string, 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))
if clientUsed[info.clientIdx] {
continue
}
clientUsed[info.clientIdx] = true
clients = append(clients, client)
clientNames = append(clientNames, client.Name())
}
if !s.disableFallback {
// Default round-robin query
for idx, client := range s.clients {
if clientUsed[idx] || client.skipFallback {
continue
}
clientUsed[idx] = true
clients = append(clients, client)
clientNames = append(clientNames, client.Name())
}
}
if len(domainRules) > 0 {
newError("domain ", domain, " matches following rules: ", domainRules).AtDebug().WriteToLog()
}
if len(clientNames) > 0 {
newError("domain ", domain, " will use DNS in order: ", clientNames).AtDebug().WriteToLog()
}
if len(clients) == 0 {
clients = append(clients, s.clients[0])
clientNames = append(clientNames, s.clients[0].Name())
newError("domain ", domain, " will use the first DNS: ", clientNames).AtDebug().WriteToLog()
}
return clients
}
func init() {
common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
return New(ctx, config.(*Config))
}))
}