diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/rawmsg.go')
-rw-r--r-- | vendor/github.com/miekg/dns/rawmsg.go | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/vendor/github.com/miekg/dns/rawmsg.go b/vendor/github.com/miekg/dns/rawmsg.go new file mode 100644 index 000000000..6e21fba7e --- /dev/null +++ b/vendor/github.com/miekg/dns/rawmsg.go @@ -0,0 +1,49 @@ +package dns + +import "encoding/binary" + +// rawSetRdlength sets the rdlength in the header of +// the RR. The offset 'off' must be positioned at the +// start of the header of the RR, 'end' must be the +// end of the RR. +func rawSetRdlength(msg []byte, off, end int) bool { + l := len(msg) +Loop: + for { + if off+1 > l { + return false + } + c := int(msg[off]) + off++ + switch c & 0xC0 { + case 0x00: + if c == 0x00 { + // End of the domainname + break Loop + } + if off+c > l { + return false + } + off += c + + case 0xC0: + // pointer, next byte included, ends domainname + off++ + break Loop + } + } + // The domainname has been seen, we at the start of the fixed part in the header. + // Type is 2 bytes, class is 2 bytes, ttl 4 and then 2 bytes for the length. + off += 2 + 2 + 4 + if off+2 > l { + return false + } + //off+1 is the end of the header, 'end' is the end of the rr + //so 'end' - 'off+2' is the length of the rdata + rdatalen := end - (off + 2) + if rdatalen > 0xFFFF { + return false + } + binary.BigEndian.PutUint16(msg[off:], uint16(rdatalen)) + return true +} |