* Use an interface method for unpacking records
* Eliminate err var declaration from unpack functions
* Remove pointless r.Data assignment in PrivateRR.unpack
* Avoid setting the Rdlength field when packing
The offset of the end of the header is now returned from the RR.pack
method, with the RDLENGTH record field being written in packRR.
To maintain compatability with callers of PackRR who might be relying
on this old behaviour, PackRR will now set rr.Header().Rdlength for
external callers. Care must be taken by callers to ensure this won't
cause a data-race.
* Prevent panic if TestClientLocalAddress fails
This came up during testing of the previous change.
* Change style of overflow check in packRR
* Reduce compression memory use with map[string]uint16
map[string]uint16 uses 25% less memory per-entry than a map[string]int
(16+2)/(16+8) = 0.75. All entries in the compression map are bound by
maxCompressionOffset which is 14-bits and fits within a uint16.
* Add PackMsg benchmark with more RRs
* Add a comment to the compressionMap struct
* Remove fullSize return from compressionLenSearch
This wasn't used anywhere but TestCompressionLenSearch, and was very
wrong.
* Add generated compressedLen functions and use them
This replaces the confusing and complicated compressionLenSlice
function.
* Use compressedLenWithCompressionMap even for uncompressed
This leaves the len() functions unused and they'll soon be removed.
This also fixes the off-by-one error of compressedLen when a (Q)NAME
is ".".
* Use Len helper instead of RR.len private method
* Merge len and compressedLen functions
* Merge compressedLen helper into Msg.Len
* Remove compress bool from compressedLenWithCompressionMap
* Merge map insertion into compressionLenSearch
This eliminates the need to loop over the domain name twice when we're
compressing the name.
* Use compressedNameLen for NSEC.NextDomain
This was a mistake.
* Remove compress from RR.len
* Add test case for multiple questions length
* Add test case for MINFO and SOA compression
These are the only RRs with multiple compressible names within the same
RR, and they were previously broken.
* Rename compressedNameLen to domainNameLen
It also handles the length of uncompressed domain names.
* Use off directly instead of len(s[:off])
* Move initial maxCompressionOffset check out of compressionLenMapInsert
This should allow us to avoid the call overhead of
compressionLenMapInsert in certain limited cases and may result in a
slight performance increase.
compressionLenMapInsert still has a maxCompressionOffset check inside
the for loop.
* Rename compressedLenWithCompressionMap to msgLenWithCompressionMap
This better reflects that it also calculates the uncompressed length.
* Merge TestMsgCompressMINFO with TestMsgCompressSOA
They're both testing the same thing.
* Remove compressionLenMapInsert
compressionLenSearch does everything compressionLenMapInsert did anyway.
* Only call compressionLenSearch in one place in domainNameLen
* Split if statement in domainNameLen
The last two commits worsened the performance of domainNameLen
noticably, this change restores it's original performance.
name old time/op new time/op delta
MsgLength-12 550ns ±13% 510ns ±21% ~ (p=0.050 n=10+10)
MsgLengthNoCompression-12 26.9ns ± 2% 27.0ns ± 1% ~ (p=0.198 n=9+10)
MsgLengthPack-12 2.30µs ±12% 2.26µs ±16% ~ (p=0.739 n=10+10)
MsgLengthMassive-12 32.9µs ± 7% 32.0µs ±10% ~ (p=0.243 n=9+10)
MsgLengthOnlyQuestion-12 9.60ns ± 1% 9.20ns ± 1% -4.16% (p=0.000 n=9+9)
* Remove stray newline from TestMsgCompressionMultipleQuestions
* Remove stray newline in length_test.go
This was introduced when resolving merge conflicts.
copyHeader() is redundant, we allocate a header and then copy the
non-pointer elements into it; we don't need to do this, because if we
just asssign rr.Hdr to something else we get the same result.
Remove copyHeader() and the generation and use of it in ztypes.go.
* Cleanup and removals
Gut rawmsg.go as most functions are not used. Reword some documentation.
Add more types to be checked for name compression.
* Yeah, we do use these
* Remove this function as well - only used one
Add dns:txt parsing helper to prevent compile errors. This allows
us to generate all unpack/pack function.
Add pack to the RR interface definition and add this method to
PrivateRR.
We still use typeToUnpack to select which types don't use reflection.
Formatters are not needs you can access the members just fine.
However the rdata Field access function are handy and non-trivial,
extend them and add a basic test.
The dns package implements String() for all RR types, but sometimes you will
need more flexibility. The functions Printf, Sprintf, etc. implemented formatted I/O
for the RR type.
Printing
The verbs:
Generic part of RRs:
%N the owner name of the RR
%C the class: IN, CH, CLASS15, etc.
%D the TTL in seconds
%Y the type: MX, A, etc.
The rdata of each RR differs, we allow each field to be printed as a string.
Rdata:
%0 the first rdata field
%1 the second rdata field
%2 the third rdata field
.. ...
%9 the nineth rdata field
%R all rdata fields
The rdata fields remain a TODO, but will be implemented using
reflection.
Changes to domain name packing and unpacking:
* Escape dot, backslash, brackets, double-quote, semi-colon and space
* Tab, line feed and carriage return become \t, \n and \r
Changes to TXT string packing and unpacking:
* Escape backslash and double-quote
* Tab, line feed and carriage return become \t, \n and \r
* Other unprintables to \DDD
Stringers do the equivalent of putting domain names and TXT strings
to the wire and back.
There is some duplication of logic. I found performance suffered when
I broke the logic out into smaller functions. I think this may have
been due to functions not being inlined for various reasons.
Tom Thorogood
Miek Gieben
Joe Farrell
Peter M. Goldstein
Andrew Tunnell-Jones
Brandon Philips