Although BIND9 documentations does not specify the possible size of offset
in $GENERATE clause, it clearly says that range must be a positive integer
between 0 and (2^31)-1. Moreover, BIND perfectly supports large offsets
which might be really handy when you're dealing with large intranets. I.e.
consider following case
```
$GENERATE 0-255 dhcp-${0,4,d} A 10.0.0.$
$GENERATE 0-255 dhcp-${256,4,d} A 10.0.1.$
$GENERATE 0-255 dhcp-${512,4,d} A 10.0.2.$
...
```
This change removes offset size check and introduces check that
0 >= (start + offset) and (end + offset) < (2^31)-1.
* Add a ParseZone test for $GENERATE.
* Add a test for modToPrintf used by $GENERATE.
* Correctly handle $GENERATE modifiers.
As per http://www.zytrax.com/books/dns/ch8/generate.html, the width and type (aka base)
components of a modifier are optional. This means that ${2,0,d}, ${2,0} and ${2} are
valid modifiers, however only the first format was previously permitted. Use default
values for the width and/or type if they are unspecified in the modifier.
* Make the error variable always named err.
Sometimes the error variable was named 'err' sometimes 'e'. Sometimes
'e' refered to an EDNS or string and not an error type.
* Use t.Errorf instead of t.Logf & t.Fail.
Remove the use of reflection when packing and unpacking, instead
generate all the pack and unpack functions using msg_generate.
This will generate zmsg.go which in turn calls the helper functions from
msg_helper.go.
This increases the speed by about ~30% while cutting back on memory
usage. Not all RRs are using it, but that will be rectified in upcoming
PR.
Most of the speed increase is in the header/question section parsing.
These functions *are* not generated, but straight forward enough. The
implementation can be found in msg.go.
The new code has been fuzzed by go-fuzz, which turned up some issues.
All files that started with 'z', and not autogenerated were renamed,
i.e. zscan.go is now scan.go.
Reflection is still used, in subsequent PRs it will be removed entirely.
Alexey Naidyonov
Joel Sing
Michael Haro
Miek Gieben