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package proxy
import (
"context"
"crypto/tls"
"errors"
"math"
"testing"
"time"
"github.com/coredns/coredns/plugin/pkg/dnstest"
"github.com/coredns/coredns/plugin/pkg/transport"
"github.com/coredns/coredns/plugin/test"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
func TestProxy(t *testing.T) {
s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
ret := new(dns.Msg)
ret.SetReply(r)
ret.Answer = append(ret.Answer, test.A("example.org. IN A 127.0.0.1"))
w.WriteMsg(ret)
})
defer s.Close()
p := NewProxy("TestProxy", s.Addr, transport.DNS)
p.readTimeout = 10 * time.Millisecond
p.Start(5 * time.Second)
m := new(dns.Msg)
m.SetQuestion("example.org.", dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
req := request.Request{Req: m, W: rec}
resp, err := p.Connect(context.Background(), req, Options{PreferUDP: true})
if err != nil {
t.Errorf("Failed to connect to testdnsserver: %s", err)
}
if x := resp.Answer[0].Header().Name; x != "example.org." {
t.Errorf("Expected %s, got %s", "example.org.", x)
}
}
func TestProxyTLSFail(t *testing.T) {
// This is an udp/tcp test server, so we shouldn't reach it with TLS.
s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
ret := new(dns.Msg)
ret.SetReply(r)
ret.Answer = append(ret.Answer, test.A("example.org. IN A 127.0.0.1"))
w.WriteMsg(ret)
})
defer s.Close()
p := NewProxy("TestProxyTLSFail", s.Addr, transport.TLS)
p.readTimeout = 10 * time.Millisecond
p.SetTLSConfig(&tls.Config{})
p.Start(5 * time.Second)
m := new(dns.Msg)
m.SetQuestion("example.org.", dns.TypeA)
rec := dnstest.NewRecorder(&test.ResponseWriter{})
req := request.Request{Req: m, W: rec}
_, err := p.Connect(context.Background(), req, Options{})
if err == nil {
t.Fatal("Expected *not* to receive reply, but got one")
}
}
func TestProtocolSelection(t *testing.T) {
p := NewProxy("TestProtocolSelection", "bad_address", transport.DNS)
p.readTimeout = 10 * time.Millisecond
stateUDP := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
stateTCP := request.Request{W: &test.ResponseWriter{TCP: true}, Req: new(dns.Msg)}
ctx := context.TODO()
go func() {
p.Connect(ctx, stateUDP, Options{})
p.Connect(ctx, stateUDP, Options{ForceTCP: true})
p.Connect(ctx, stateUDP, Options{PreferUDP: true})
p.Connect(ctx, stateUDP, Options{PreferUDP: true, ForceTCP: true})
p.Connect(ctx, stateTCP, Options{})
p.Connect(ctx, stateTCP, Options{ForceTCP: true})
p.Connect(ctx, stateTCP, Options{PreferUDP: true})
p.Connect(ctx, stateTCP, Options{PreferUDP: true, ForceTCP: true})
}()
for i, exp := range []string{"udp", "tcp", "udp", "tcp", "tcp", "tcp", "udp", "tcp"} {
proto := <-p.transport.dial
p.transport.ret <- nil
if proto != exp {
t.Errorf("Unexpected protocol in case %d, expected %q, actual %q", i, exp, proto)
}
}
}
func TestProxyIncrementFails(t *testing.T) {
var testCases = []struct {
name string
fails uint32
expectFails uint32
}{
{
name: "increment fails counter overflows",
fails: math.MaxUint32,
expectFails: math.MaxUint32,
},
{
name: "increment fails counter",
fails: 0,
expectFails: 1,
},
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
p := NewProxy("TestProxyIncrementFails", "bad_address", transport.DNS)
p.fails = tc.fails
p.incrementFails()
if p.fails != tc.expectFails {
t.Errorf("Expected fails to be %d, got %d", tc.expectFails, p.fails)
}
})
}
}
func TestCoreDNSOverflow(t *testing.T) {
s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
ret := new(dns.Msg)
ret.SetReply(r)
answers := []dns.RR{
test.A("example.org. IN A 127.0.0.1"),
test.A("example.org. IN A 127.0.0.2"),
test.A("example.org. IN A 127.0.0.3"),
test.A("example.org. IN A 127.0.0.4"),
test.A("example.org. IN A 127.0.0.5"),
test.A("example.org. IN A 127.0.0.6"),
test.A("example.org. IN A 127.0.0.7"),
test.A("example.org. IN A 127.0.0.8"),
test.A("example.org. IN A 127.0.0.9"),
test.A("example.org. IN A 127.0.0.10"),
test.A("example.org. IN A 127.0.0.11"),
test.A("example.org. IN A 127.0.0.12"),
test.A("example.org. IN A 127.0.0.13"),
test.A("example.org. IN A 127.0.0.14"),
test.A("example.org. IN A 127.0.0.15"),
test.A("example.org. IN A 127.0.0.16"),
test.A("example.org. IN A 127.0.0.17"),
test.A("example.org. IN A 127.0.0.18"),
test.A("example.org. IN A 127.0.0.19"),
test.A("example.org. IN A 127.0.0.20"),
}
ret.Answer = answers
w.WriteMsg(ret)
})
defer s.Close()
p := NewProxy("TestCoreDNSOverflow", s.Addr, transport.DNS)
p.readTimeout = 10 * time.Millisecond
p.Start(5 * time.Second)
defer p.Stop()
// Test different connection modes
testConnection := func(proto string, options Options, expectTruncated bool) {
t.Helper()
queryMsg := new(dns.Msg)
queryMsg.SetQuestion("example.org.", dns.TypeA)
recorder := dnstest.NewRecorder(&test.ResponseWriter{})
request := request.Request{Req: queryMsg, W: recorder}
response, err := p.Connect(context.Background(), request, options)
if err != nil {
t.Errorf("Failed to connect to testdnsserver: %s", err)
}
if response.Truncated != expectTruncated {
t.Errorf("Expected truncated response for %s, but got TC flag %v", proto, response.Truncated)
}
}
// Test PreferUDP, expect truncated response
testConnection("PreferUDP", Options{PreferUDP: true}, true)
// Test ForceTCP, expect no truncated response
testConnection("ForceTCP", Options{ForceTCP: true}, false)
// Test No options specified, expect truncated response
testConnection("NoOptionsSpecified", Options{}, true)
// Test both TCP and UDP provided, expect no truncated response
testConnection("BothTCPAndUDP", Options{PreferUDP: true, ForceTCP: true}, false)
}
func TestShouldTruncateResponse(t *testing.T) {
testCases := []struct {
testname string
err error
expected bool
}{
{"BadAlgorithm", dns.ErrAlg, false},
{"BufferSizeTooSmall", dns.ErrBuf, true},
{"OverflowUnpackingA", errors.New("overflow unpacking a"), true},
{"OverflowingHeaderSize", errors.New("overflowing header size"), true},
{"OverflowpackingA", errors.New("overflow packing a"), true},
{"ErrSig", dns.ErrSig, false},
}
for _, tc := range testCases {
t.Run(tc.testname, func(t *testing.T) {
result := shouldTruncateResponse(tc.err)
if result != tc.expected {
t.Errorf("For testname '%v', expected %v but got %v", tc.testname, tc.expected, result)
}
})
}
}
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