mirror of
https://github.com/coredns/coredns.git
synced 2025-11-03 18:53:13 -05:00
61 lines
1.5 KiB
Go
61 lines
1.5 KiB
Go
package test
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import (
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"net"
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"testing"
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"github.com/miekg/dns"
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)
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func TestCompressScrub(t *testing.T) {
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corefile := `example.org:0 {
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erratic {
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drop 0
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delay 0
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large
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}
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}`
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i, udp, _, err := CoreDNSServerAndPorts(corefile)
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if err != nil {
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t.Fatalf("Could not get CoreDNS serving instance: %s", err)
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}
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defer i.Stop()
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c, err := net.Dial("udp", udp)
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if err != nil {
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t.Fatalf("Could not dial %s", err)
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}
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m := new(dns.Msg)
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m.SetQuestion("example.org.", dns.TypeA)
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q, _ := m.Pack()
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c.Write(q)
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buf := make([]byte, 1024)
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n, err := c.Read(buf)
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if err != nil || n == 0 {
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t.Errorf("Expected reply, got: %s", err)
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return
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}
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if n >= 512 {
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t.Fatalf("Expected returned packet to be < 512, got %d", n)
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}
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buf = buf[:n]
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// If there is compression in the returned packet we should look for compression pointers, if found
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// the pointers should return to the domain name in the query (the first domain name that's available for
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// compression. This means we're looking for a combo where the pointers is detected and the offset is 12
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// the position of the first name after the header. The erratic plugin adds 30 RRs that should all be compressed.
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found := 0
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for i := 0; i < len(buf)-1; i++ {
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if buf[i]&0xC0 == 0xC0 {
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off := (int(buf[i])^0xC0)<<8 | int(buf[i+1])
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if off == 12 {
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found++
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}
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}
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}
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if found != 30 {
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t.Errorf("Failed to find all compression pointers in the packet, wanted 30, got %d", found)
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}
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}
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