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cmd/cli: use OS resolver as default upstream for SRV lan hostname

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Since application may need SRV record for public domains, which could be
blocked by OS resolver, but not with remote upstreams.

This was reported by a Minecraft user, who seeing thing is broken after
upgrading to v1.4.0 release.
This commit is contained in:
Cuong Manh Le
2025-02-19 22:50:15 +07:00
committed by Cuong Manh Le
parent 5b1faf1ce3
commit c7168739c7
3 changed files with 32 additions and 22 deletions
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45
cmd/cli/dns_proxy.go
View File

@@ -435,14 +435,17 @@ func (p *prog) proxy(ctx context.Context, req *proxyRequest) *proxyResponse {
if len(upstreamConfigs) == 0 {
upstreamConfigs = []*ctrld.UpstreamConfig{osUpstreamConfig}
upstreams = []string{upstreamOS}
}
if p.isAdDomainQuery(req.msg) {
ctrld.Log(ctx, mainLog.Load().Debug(),
"AD domain query detected for %s in domain %s",
req.msg.Question[0].Name, p.adDomain)
upstreamConfigs = []*ctrld.UpstreamConfig{localUpstreamConfig}
upstreams = []string{upstreamOS}
// For OS resolver, local addresses are ignored to prevent possible looping.
// However, on Active Directory Domain Controller, where it has local DNS server
// running and listening on local addresses, these local addresses must be used
// as nameservers, so queries for ADDC could be resolved as expected.
if p.isAdDomainQuery(req.msg) {
ctrld.Log(ctx, mainLog.Load().Debug(),
"AD domain query detected for %s in domain %s",
req.msg.Question[0].Name, p.adDomain)
upstreamConfigs = []*ctrld.UpstreamConfig{localUpstreamConfig}
upstreams = []string{upstreamOSLocal}
}
}
res := &proxyResponse{}
@@ -458,7 +461,7 @@ func (p *prog) proxy(ctx context.Context, req *proxyRequest) *proxyResponse {
ctrld.Log(ctx, mainLog.Load().Debug(), "%s, %s, %s -> %v", req.ufr.matchedPolicy, req.ufr.matchedNetwork, req.ufr.matchedRule, upstreams)
} else {
switch {
case isSrvLookup(req.msg):
case isSrvLanLookup(req.msg):
upstreams = []string{upstreamOS}
upstreamConfigs = []*ctrld.UpstreamConfig{osUpstreamConfig}
ctx = ctrld.LanQueryCtx(ctx)
@@ -1109,21 +1112,27 @@ func isLanHostnameQuery(m *dns.Msg) bool {
default:
return false
}
name := strings.TrimSuffix(q.Name, ".")
return isLanHostname(q.Name)
}
// isSrvLanLookup reports whether DNS message is an SRV query of a LAN hostname.
func isSrvLanLookup(m *dns.Msg) bool {
if m == nil || len(m.Question) == 0 {
return false
}
q := m.Question[0]
return q.Qtype == dns.TypeSRV && isLanHostname(q.Name)
}
// isLanHostname reports whether name is a LAN hostname.
func isLanHostname(name string) bool {
name = strings.TrimSuffix(name, ".")
return !strings.Contains(name, ".") ||
strings.HasSuffix(name, ".domain") ||
strings.HasSuffix(name, ".lan") ||
strings.HasSuffix(name, ".local")
}
// isSrvLookup reports whether DNS message is a SRV query.
func isSrvLookup(m *dns.Msg) bool {
if m == nil || len(m.Question) == 0 {
return false
}
return m.Question[0].Qtype == dns.TypeSRV
}
// isWanClient reports whether the input is a WAN address.
func isWanClient(na net.Addr) bool {
var ip netip.Addr

7
cmd/cli/dns_proxy_test.go
View File

@@ -418,20 +418,21 @@ func Test_isPrivatePtrLookup(t *testing.T) {
}
}
func Test_isSrvLookup(t *testing.T) {
func Test_isSrvLanLookup(t *testing.T) {
tests := []struct {
name string
msg *dns.Msg
isSrvLookup bool
}{
{"SRV", newDnsMsgWithHostname("foo", dns.TypeSRV), true},
{"SRV LAN", newDnsMsgWithHostname("foo", dns.TypeSRV), true},
{"Not SRV", newDnsMsgWithHostname("foo", dns.TypeNone), false},
{"Not SRV LAN", newDnsMsgWithHostname("controld.com", dns.TypeSRV), false},
}
for _, tc := range tests {
tc := tc
t.Run(tc.name, func(t *testing.T) {
t.Parallel()
if got := isSrvLookup(tc.msg); tc.isSrvLookup != got {
if got := isSrvLanLookup(tc.msg); tc.isSrvLookup != got {
t.Errorf("unexpected result, want: %v, got: %v", tc.isSrvLookup, got)
}
})

2
cmd/cli/prog.go
View File

@@ -43,7 +43,7 @@ const (
ctrldControlUnixSockMobile = "cd.sock"
upstreamPrefix = "upstream."
upstreamOS = upstreamPrefix + "os"
upstreamPrivate = upstreamPrefix + "private"
upstreamOSLocal = upstreamOS + ".local"
dnsWatchdogDefaultInterval = 20 * time.Second
ctrldServiceName = "ctrld"
)