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fix(rewrite): truncated upstream response (#7277)

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Forward information that a upstream response is truncated when rewriting
a CNAME. Otherwise, the cache plugin stores the truncated resonse,
making it impossible to receive the full response as a client via TCP.

Signed-off-by: Yannick Epstein <yannicke@spotify.com>
This commit is contained in:
Yannick Epstein
2025-05-01 16:59:15 +02:00
committed by GitHub
parent abb0a52c5f
commit 13da7f749c
2 changed files with 35 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
plugin/rewrite/cname_target.go
View File

@@ -100,6 +100,9 @@ func (r *cnameTargetRuleWithReqState) RewriteResponse(res *dns.Msg, rr dns.RR) {
}
}
res.Answer = newAnswer
// if not propagated, the truncated response might get cached,
// and it will be impossible to resolve the full response
res.Truncated = upRes.Truncated
}
}
}

36
plugin/rewrite/cname_target_test.go
View File

@@ -53,6 +53,12 @@ func (u *MockedUpstream) Lookup(ctx context.Context, state request.Request, name
test.A("orders.webapp.eu.org. 120 IN A 20.0.0.9"),
}
return m, nil
case "music.truncated.spotify.com.":
m.Answer = []dns.RR{
test.A("music.truncated.spotify.com. 120 IN A 10.1.0.9"),
}
m.Truncated = true
return m, nil
}
return &dns.Msg{}, nil
}
@@ -68,6 +74,7 @@ func TestCNameTargetRewrite(t *testing.T) {
{[]string{"continue", "cname", "suffix", "uvw.", "xyz."}, reflect.TypeOf(&cnameTargetRule{})},
{[]string{"continue", "cname", "substring", "efgh", "zzzz.www"}, reflect.TypeOf(&cnameTargetRule{})},
{[]string{"continue", "cname", "regex", `(.*)\.web\.(.*)\.site\.`, `{1}.webapp.{2}.org.`}, reflect.TypeOf(&cnameTargetRule{})},
{[]string{"continue", "cname", "exact", "music.truncated.spotify.com.", "music.truncated.spotify.com."}, reflect.TypeOf(&cnameTargetRule{})},
}
for i, r := range ruleset {
rule, err := newRule(r.args...)
@@ -86,10 +93,11 @@ func TestCNameTargetRewrite(t *testing.T) {
func doTestCNameTargetTests(rules []Rule, t *testing.T) {
tests := []struct {
from string
fromType uint16
answer []dns.RR
expectedAnswer []dns.RR
from string
fromType uint16
answer []dns.RR
expectedAnswer []dns.RR
expectedTruncated bool
}{
{"abc.example.com", dns.TypeA,
[]dns.RR{
@@ -100,6 +108,7 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.CNAME("abc.example.com. 5 IN CNAME xyz.example.com."),
test.A("xyz.example.com. 3600 IN A 3.4.5.6"),
},
false,
},
{"abc.example.com", dns.TypeAAAA,
[]dns.RR{
@@ -110,6 +119,7 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.CNAME("abc.example.com. 5 IN CNAME xyz.example.com."),
test.AAAA("xyz.example.com. 3600 IN AAAA 3a01:7e00::f03c:91ff:fe79:234c"),
},
false,
},
{"chat.openai.com", dns.TypeA,
[]dns.RR{
@@ -121,6 +131,7 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.CNAME("chat.openai.com. 20 IN CNAME bard.google.com.cdn.cloudflare.net."),
test.A("bard.google.com.cdn.cloudflare.net. 1800 IN A 9.7.2.1"),
},
false,
},
{"coredns.io", dns.TypeA,
[]dns.RR{
@@ -131,6 +142,7 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.CNAME("coredns.io. 100 IN CNAME www.hosting.xyz."),
test.A("www.hosting.xyz. 500 IN A 20.30.40.50"),
},
false,
},
{"core.dns.rocks", dns.TypeA,
[]dns.RR{
@@ -142,6 +154,7 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.A("abcd.zzzz.www.pqrst. 120 IN A 101.20.5.1"),
test.A("abcd.zzzz.www.pqrst. 120 IN A 101.20.5.2"),
},
false,
},
{"order.service.eu", dns.TypeA,
[]dns.RR{
@@ -152,6 +165,17 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
test.CNAME("order.service.eu. 200 IN CNAME orders.webapp.eu.org."),
test.A("orders.webapp.eu.org. 120 IN A 20.0.0.9"),
},
false,
},
{"music.spotify.com", dns.TypeA,
[]dns.RR{
test.CNAME("music.spotify.com. 200 IN CNAME music.truncated.spotify.com."),
},
[]dns.RR{
test.CNAME("music.spotify.com. 200 IN CNAME music.truncated.spotify.com."),
test.A("music.truncated.spotify.com. 120 IN A 10.1.0.9"),
},
true,
},
}
ctx := context.TODO()
@@ -176,5 +200,9 @@ func doTestCNameTargetTests(rules []Rule, t *testing.T) {
i, tc.from, tc.fromType, resp.Answer, tc.expectedAnswer)
continue
}
if resp.Truncated != tc.expectedTruncated {
t.Errorf("Test %d: FAIL %s (%d) Actual and expected truncated flag do not match, actual: %v, expected: %v",
i, tc.from, tc.fromType, resp.Truncated, tc.expectedTruncated)
}
}
}