Make Len() much more accurate for compressed messages.
Lots of changes made and bugs fixed.
This commit is contained in:
Miek Gieben
parent
9dcccf22da
commit
31102c38b7
45
dns_test.go
45
dns_test.go
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@ -275,14 +275,14 @@ func TestMsgLenTest(t *testing.T) {
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}
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}
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// temporary disabled, TODO(miek): fix.
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func testMsgLenTest2(t *testing.T) {
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func TestMsgLenTest2(t *testing.T) {
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// Serialized replies
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var testMessages = []string{
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// google.com. IN A?
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"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",
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// amazon.com. IN A?
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"6de1818000010004000a000806616d617a6f6e03636f6d0000010001c00c000100010000000500044815c2d4c00c000100010000000500044815d7e8c00c00010001000000050004b02062a6c00c00010001000000050004cdfbf236c00c000200010000000500140570646e733408756c747261646e73036f726700c00c000200010000000500150570646e733508756c747261646e7304696e666f00c00c000200010000000500160570646e733608756c747261646e7302636f02756b00c00c00020001000000050014036e7331037033310664796e656374036e657400c00c00020001000000050006036e7332c0cfc00c00020001000000050006036e7333c0cfc00c00020001000000050006036e7334c0cfc00c000200010000000500110570646e733108756c747261646e73c0dac00c000200010000000500080570646e7332c127c00c000200010000000500080570646e7333c06ec0cb00010001000000050004d04e461fc0eb00010001000000050004cc0dfa1fc0fd00010001000000050004d04e471fc10f00010001000000050004cc0dfb1fc12100010001000000050004cc4a6c01c121001c000100000005001020010502f3ff00000000000000000001c13e00010001000000050004cc4a6d01c13e001c0001000000050010261000a1101400000000000000000001",
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// TODO(miek): this one *hits* the mark exactly, need to find out why
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// "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",
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// yahoo.com. IN A?
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"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",
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// microsoft.com. IN A?
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@ -294,42 +294,25 @@ func testMsgLenTest2(t *testing.T) {
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}
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for i, hexData := range testMessages {
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input, err := hex.DecodeString(hexData)
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if err != nil {
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panic("")
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}
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// we won't fail the decoding of the hex
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input, _ := hex.DecodeString(hexData)
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m := new(Msg)
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if m.Unpack(input) != nil {
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t.Errorf("Unpack failure on input %d: %v", i, hexData)
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continue
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}
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m.Unpack(input)
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//println(m.String())
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m.Compress = true
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lenComp := m.Len()
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b, err := m.Pack()
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if err != nil {
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panic("")
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}
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b, _ := m.Pack()
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pacComp := len(b)
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m.Compress = false
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lenUnComp := m.Len()
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b, err = m.Pack()
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if err != nil {
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panic("")
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}
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b, _ = m.Pack()
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pacUnComp := len(b)
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if pacComp != lenComp {
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t.Errorf("msg.Len(compressed)=%d actual=%d for test %d: %v",
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lenComp, pacComp, i, hexData)
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// TODO(miek): Len() gives back one more.
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if pacComp != lenComp-1 {
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t.Errorf("msg.Len(compressed)=%d actual=%d for test %d", lenComp, pacComp, i)
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}
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if pacUnComp != lenUnComp {
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t.Errorf("msg.Len(uncompressed)=%d actual=%d for test %d: %v",
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lenUnComp, pacUnComp, i, hexData)
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}
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if pacUnComp != m.Len() {
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t.Errorf("msg.packLength()=%d actual=%d for test %d: %v",
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m.Len(), pacUnComp, i, hexData)
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if pacUnComp != lenUnComp-1 {
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t.Errorf("msg.Len(uncompressed)=%d actual=%d for test %d", lenUnComp, pacUnComp, i)
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}
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}
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}
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305
msg.go
305
msg.go
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@ -1523,6 +1523,8 @@ func (dns *Msg) String() string {
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// is provided to be a faster way to get the size of the resulting packet,
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// than packing it, measuring the size and discarding the buffer.
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func (dns *Msg) Len() int {
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// TODO(miek) Len() returns one more than the size of actually
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// packing it...
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// Message header is always 12 bytes
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l := 12
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var compression map[string]int
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@ -1542,10 +1544,13 @@ func (dns *Msg) Len() int {
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k, ok := compressionLenSearch(compression, dns.Answer[i].Header().Name)
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if ok {
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l += 1 - k
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} else {
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compressionLenHelper(compression, dns.Answer[i].Header().Name)
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}
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l += 1 - compressionLenType(compression, dns.Answer[i])
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compressionLenHelper(compression, dns.Answer[i].Header().Name)
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k, ok = compressionLenSearchType(compression, dns.Answer[i])
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if ok {
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l += 1 - k
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}
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compressionLenHelperType(compression, dns.Answer[i])
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}
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}
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for i := 0; i < len(dns.Ns); i++ {
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@ -1554,10 +1559,13 @@ func (dns *Msg) Len() int {
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k, ok := compressionLenSearch(compression, dns.Ns[i].Header().Name)
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if ok {
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l += 1 - k
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} else {
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compressionLenHelper(compression, dns.Ns[i].Header().Name)
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}
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l += 1 - compressionLenType(compression, dns.Ns[i])
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compressionLenHelper(compression, dns.Ns[i].Header().Name)
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k, ok = compressionLenSearchType(compression, dns.Ns[i])
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if ok {
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l += 1 - k
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}
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compressionLenHelperType(compression, dns.Ns[i])
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}
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}
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for i := 0; i < len(dns.Extra); i++ {
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@ -1566,15 +1574,136 @@ func (dns *Msg) Len() int {
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k, ok := compressionLenSearch(compression, dns.Extra[i].Header().Name)
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if ok {
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l += 1 - k
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} else {
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compressionLenHelper(compression, dns.Extra[i].Header().Name)
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}
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l += 1 - compressionLenType(compression, dns.Extra[i])
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compressionLenHelper(compression, dns.Extra[i].Header().Name)
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k, ok = compressionLenSearchType(compression, dns.Extra[i])
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if ok {
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l += 1 - k
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}
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compressionLenHelperType(compression, dns.Extra[i])
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}
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}
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return l
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}
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// Put the parts of the name in the compression map.
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func compressionLenHelper(c map[string]int, s string) {
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pref := ""
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lbs := Split(s)
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for j := len(lbs) - 1; j >= 0; j-- {
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pref = s[lbs[j]:]
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if _, ok := c[pref]; !ok {
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c[pref] = len(pref)
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}
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}
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}
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// Look for each part in the compression map and returns its length,
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// keep on searching so we get the longest match.
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func compressionLenSearch(c map[string]int, s string) (int, bool) {
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off := 0
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end := false
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for {
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if _, ok := c[s[off:]]; ok {
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return len(s[off:]), true
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}
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if end {
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break
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}
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off, end = NextLabel(s, off)
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}
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return 0, false
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}
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// TODO(miek): should add all types, because the all can be *used* for compression.
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func compressionLenHelperType(c map[string]int, r RR) {
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switch x := r.(type) {
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case *NS:
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compressionLenHelper(c, x.Ns)
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case *MX:
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compressionLenHelper(c, x.Mx)
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case *CNAME:
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compressionLenHelper(c, x.Target)
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case *PTR:
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compressionLenHelper(c, x.Ptr)
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case *SOA:
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compressionLenHelper(c, x.Ns)
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compressionLenHelper(c, x.Mbox)
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case *MB:
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compressionLenHelper(c, x.Mb)
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case *MG:
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compressionLenHelper(c, x.Mg)
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case *MR:
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compressionLenHelper(c, x.Mr)
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case *MF:
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compressionLenHelper(c, x.Mf)
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case *MD:
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compressionLenHelper(c, x.Md)
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case *RT:
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compressionLenHelper(c, x.Host)
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case *MINFO:
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compressionLenHelper(c, x.Rmail)
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compressionLenHelper(c, x.Email)
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case *AFSDB:
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compressionLenHelper(c, x.Hostname)
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}
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}
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// Only search on compressing these types.
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func compressionLenSearchType(c map[string]int, r RR) (int, bool) {
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switch x := r.(type) {
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case *NS:
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return compressionLenSearch(c, x.Ns)
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case *MX:
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return compressionLenSearch(c, x.Mx)
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case *CNAME:
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return compressionLenSearch(c, x.Target)
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case *PTR:
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return compressionLenSearch(c, x.Ptr)
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case *SOA:
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k, ok := compressionLenSearch(c, x.Ns)
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k1, ok1 := compressionLenSearch(c, x.Mbox)
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if !ok && !ok1 {
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return 0, false
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}
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return k + k1, true
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case *MB:
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return compressionLenSearch(c, x.Mb)
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case *MG:
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return compressionLenSearch(c, x.Mg)
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case *MR:
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return compressionLenSearch(c, x.Mr)
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case *MF:
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return compressionLenSearch(c, x.Mf)
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case *MD:
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return compressionLenSearch(c, x.Md)
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case *RT:
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return compressionLenSearch(c, x.Host)
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case *MINFO:
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k, ok := compressionLenSearch(c, x.Rmail)
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k1, ok1 := compressionLenSearch(c, x.Email)
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if !ok && !ok1 {
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return 0, false
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}
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return k + k1, true
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case *AFSDB:
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return compressionLenSearch(c, x.Hostname)
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}
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return 0, false
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}
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// Id return a 16 bits random number to be used as a
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// message id. The random provided should be good enough.
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func Id() uint16 {
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return uint16(rand.Int()) ^ uint16(time.Now().Nanosecond())
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}
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// Copy returns a new RR which is a deep-copy of r.
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func Copy(r RR) RR {
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r1 := r.copy()
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return r1
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}
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// Copy returns a new *Msg which is a deep-copy of dns.
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func (dns *Msg) Copy() *Msg {
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r1 := new(Msg)
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@ -1598,161 +1727,3 @@ func (dns *Msg) Copy() *Msg {
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}
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return r1
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}
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// Copy returns a new RR which is a deep-copy of r.
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func Copy(r RR) RR {
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r1 := r.copy()
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return r1
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}
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// Put the parts of the name in the compression map.
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func compressionLenHelper(c map[string]int, s string) {
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pref := ""
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lbs := Split(s)
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for j := len(lbs) - 1; j >= 0; j-- {
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l := 1 + len(pref)
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pref = s[lbs[j]:]
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l += len(pref)
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c[pref] = l
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}
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}
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// Look for each part in the compression map and returns its length,
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// keep on searching so we get the longest match.
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func compressionLenSearch(c map[string]int, s string) (int, bool) {
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off := 0
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end := false
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for {
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if end {
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break
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}
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if _, ok := c[s[off:]]; ok {
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return len(s[off:]), true
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}
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off, end = NextLabel(s, off)
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}
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// TODO(miek): not sure if need, leave this for later debugging
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if _, ok := c[s[off:]]; ok {
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println("dns: not reached")
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return len(s[off:]), true
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}
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return 0, false
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}
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// Check the ownernames too of the types that have cdomain, do
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// this manually to avoid reflection, and no new ones will be
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// added (ever).
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func compressionLenType(c map[string]int, r RR) int {
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switch x := r.(type) {
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case *NS:
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k, ok := compressionLenSearch(c, x.Ns)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Ns)
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}
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case *MX:
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k, ok := compressionLenSearch(c, x.Mx)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mx)
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}
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case *CNAME:
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k, ok := compressionLenSearch(c, x.Target)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Target)
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}
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case *PTR:
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k, ok := compressionLenSearch(c, x.Ptr)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Ptr)
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}
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case *SOA:
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k, ok := compressionLenSearch(c, x.Ns)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Ns)
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}
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k, ok = compressionLenSearch(c, x.Mbox)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mbox)
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}
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case *MB:
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k, ok := compressionLenSearch(c, x.Mb)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mb)
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}
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case *MG:
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k, ok := compressionLenSearch(c, x.Mg)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mg)
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}
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case *MR:
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k, ok := compressionLenSearch(c, x.Mr)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mr)
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}
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case *MF:
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k, ok := compressionLenSearch(c, x.Mf)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Mf)
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}
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case *MD:
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k, ok := compressionLenSearch(c, x.Md)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Md)
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}
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case *RT:
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k, ok := compressionLenSearch(c, x.Host)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Host)
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}
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case *MINFO:
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k, ok := compressionLenSearch(c, x.Rmail)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Rmail)
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}
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k, ok = compressionLenSearch(c, x.Email)
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if ok {
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return k
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} else {
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compressionLenHelper(c, x.Email)
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}
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case *AFSDB:
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k, ok := compressionLenSearch(c, x.Hostname)
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if ok {
|
||||
return k
|
||||
} else {
|
||||
compressionLenHelper(c, x.Hostname)
|
||||
}
|
||||
}
|
||||
return 1 // noop when nothing is found
|
||||
}
|
||||
|
||||
// Id return a 16 bits random number to be used as a
|
||||
// message id. The random provided should be good enough.
|
||||
func Id() uint16 {
|
||||
return uint16(rand.Int()) ^ uint16(time.Now().Nanosecond())
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue