122 lines
2.6 KiB
Go
122 lines
2.6 KiB
Go
package dns
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import (
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"fmt"
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"net"
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"strings"
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"github.com/Dreamacro/clash/common/cache"
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"github.com/Dreamacro/clash/component/fakeip"
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"github.com/Dreamacro/clash/log"
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D "github.com/miekg/dns"
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)
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type handler func(w D.ResponseWriter, r *D.Msg)
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func withFakeIP(cache *cache.Cache, pool *fakeip.Pool) handler {
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return func(w D.ResponseWriter, r *D.Msg) {
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q := r.Question[0]
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cacheItem := cache.Get("fakeip:" + q.String())
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if cacheItem != nil {
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msg := cacheItem.(*D.Msg).Copy()
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setMsgTTL(msg, 1)
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msg.SetReply(r)
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w.WriteMsg(msg)
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return
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}
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rr := &D.A{}
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rr.Hdr = D.RR_Header{Name: q.Name, Rrtype: D.TypeA, Class: D.ClassINET, Ttl: dnsDefaultTTL}
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ip := pool.Get()
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rr.A = ip
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msg := r.Copy()
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msg.Answer = []D.RR{rr}
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putMsgToCache(cache, "fakeip:"+q.String(), msg)
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putMsgToCache(cache, ip.String(), msg)
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setMsgTTL(msg, 1)
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w.WriteMsg(msg)
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return
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}
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}
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func withResolver(resolver *Resolver) handler {
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return func(w D.ResponseWriter, r *D.Msg) {
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msg, err := resolver.Exchange(r)
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if err != nil {
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q := r.Question[0]
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qString := fmt.Sprintf("%s %s %s", q.Name, D.Class(q.Qclass).String(), D.Type(q.Qtype).String())
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log.Debugln("[DNS Server] Exchange %s failed: %v", qString, err)
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D.HandleFailed(w, r)
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return
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}
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msg.SetReply(r)
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w.WriteMsg(msg)
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return
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}
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}
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func withHost(resolver *Resolver, next handler) handler {
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hosts := resolver.hosts
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if hosts == nil {
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panic("dns/withHost: hosts should not be nil")
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}
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return func(w D.ResponseWriter, r *D.Msg) {
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q := r.Question[0]
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if q.Qtype != D.TypeA && q.Qtype != D.TypeAAAA {
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next(w, r)
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return
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}
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domain := strings.TrimRight(q.Name, ".")
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host := hosts.Search(domain)
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if host == nil {
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next(w, r)
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return
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}
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ip := host.Data.(net.IP)
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if q.Qtype == D.TypeAAAA && ip.To16() == nil {
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next(w, r)
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return
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} else if q.Qtype == D.TypeA && ip.To4() == nil {
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next(w, r)
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return
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}
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var rr D.RR
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if q.Qtype == D.TypeAAAA {
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record := &D.AAAA{}
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record.Hdr = D.RR_Header{Name: q.Name, Rrtype: D.TypeAAAA, Class: D.ClassINET, Ttl: dnsDefaultTTL}
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record.AAAA = ip
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rr = record
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} else {
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record := &D.A{}
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record.Hdr = D.RR_Header{Name: q.Name, Rrtype: D.TypeA, Class: D.ClassINET, Ttl: dnsDefaultTTL}
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record.A = ip
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rr = record
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}
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msg := r.Copy()
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msg.Answer = []D.RR{rr}
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msg.SetReply(r)
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w.WriteMsg(msg)
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return
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}
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}
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func newHandler(resolver *Resolver) handler {
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if resolver.IsFakeIP() {
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return withFakeIP(resolver.cache, resolver.pool)
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}
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if resolver.hosts != nil {
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return withHost(resolver, withResolver(resolver))
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}
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return withResolver(resolver)
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}
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