When a pointer points to a empty name, the "return '.'" special case used to
kick in which is not pointer-aware so it would reset the parsing offset to
the pointer target
This was independently found and fixed in c13d4ee, I'm submitting this patch
anyway as it seems a bit more robust and DRY [citation needed].
If the root label is compressed (which is 2 bytes, the root label
itself is only 1 byte, so why do it?), go dns incorrectly set the
offset when encountering such a name.
Fixes#234
A handful of EDNS options have been standardized, and they each have a type defined in GoDNS. However there is currently no way a development team can use GoDNS with internally defined options, or with new options that may be proposed in the future.
This change solves the problem by giving users an EDNS0_CUSTOM type to allow clients to send, and servers to receive, custom EDNS options.
If you have a system with large amounts of copies, these slice
allocations start stacking up. Use a shared slice and then subslice
them with a cap limit so that append works properly.
Also, add a benchmark and test for Msg.Copy
Benchcmp:
benchmark old ns/op new ns/op delta
BenchmarkCopy 1880 1672 -11.06%
benchmark old allocs new allocs delta
BenchmarkCopy 13 11 -15.38%
benchmark old bytes new bytes delta
BenchmarkCopy 528 528 +0.00%
IPSECKEY is kinda strange because it has a type selector which tells
what type a later rdata field has. The type can be a domainname, address
or v6 address. You sort of wish Go would have a union type for this, but
alas.
Currently this is implemented as:
GatewayA net.IP `dns:"a"`
GatewayAAAA net.IP `dns:"aaaa"`
GatewayName string `dns:"domain-name"`
In the IPSECKEY. Only one of these is active at any one time. When
parsing/packing and unpacking the value of GatewayType is checked
to see what to do.
Parsing from strings is also implemented properly and tested. The Unpack
function still needs work.
ECDSA public keys consist of a single value, called "Q" in FIPS
186-3. In DNSSEC keys, Q is a simple bit string that represents the
uncompressed form of a curve point, "x | y".
The ECDSA signature is the combination of two non-negative integers,
called "r" and "s" in FIPS 186-3. The two integers, each of which is
formatted as a simple octet string, are combined into a single longer
octet string for DNSSEC as the concatenation "r | s". (Conversion of
the integers to bit strings is described in Section C.2 of FIPS
186-3.) For P-256, each integer MUST be encoded as 32 octets; for
P-384, each integer MUST be encoded as 48 octets.
Instead of going through the fmt package, we can use append int,
which saves an allocation.
benchmark old ns/op new ns/op delta
BenchmarkUnpackDomainNameUnprintable 2147 506 -76.43%
This is based on @miekg's sig0 branch. That branch diverged from master
and I didn't want to wander off on a rebase.
As implemented there's no allowance for multi-envelope (TCP) support.
TODO:
* unpackUint32() could be moved out and used elsewhere
* tests
* multi-envelope support (if useful)
This way the Id function can be overruled by clients to have
another implementation for the Id function:
To make it static: dns.Id = func() uint16 { return 1234 }
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.
packLen() was a featureless mirror of Len(). Remove it, and just use
Len() internally too.
Fix bug in Len() too, where the length of the additional section was
not counted.
If the TC bit is set in a message, we will probably try to parse
half a message, which will fail. To fix this just return a message
header and the question section and don't parse the rest.
msg.Pack() always allocates a byte slice. This is good for simplicity,
but in a serious application it's preferable to reuse byte slices to
reduce the GC overhead. This patch introduces a new public method:
PackBuffer(). It's exaclty like Pack() but is able to reuse a
given byte slice. It will still allocate a new slice if the given one
is too small.
This new functions just compiles the domain to wire format, if that
works, the name is deemed OK. It is also much less strict than the
older code. Almost everything is allowed in the name, except two
dots back to back (there is an explicit test for that).
Empty or no rdata is allowed for dynamic updates, so test if this
works for packing/unpacking. It only fails for TSIG (which is
never seen in zone files), SOA (which is not seen like this in dyn.
updates) and WKS (just an old record).
packLen() returns the length of an uncompressed packet buffer, this
is used when packing a packet. This is needed for compression. When
compression is used, we first create the full packet and *then*
compress it. If we use Len() which accounts for compression, we can
get buffer overruns, when packing the (then still uncompressed) packet.
The "other" edns0 option will then become LONG_LIVED_QUERIES which
is way to long to be practical, so I want to make it LLQ, UPDATE_LEASE
then needs to be come UL.
This will probably impact no-one, because noone uses this (I hope)
Miek Gieben
Filippo Valsorda
Roland Shoemaker
Harvo Jones
Michael Haro
Daniel Morsing
Andrew Tunnell-Jones
Alex Sergeyev
Marek Majkowski
Alex Ciuba
soh335
Skinner, Alex
Ask Bjørn Hansen