Domain name labels

[richardschneider]

The standard requires that domain name labels consist of only USASCII letters, digits or '-'. This is somewhat mitigated by Internationalized Domain Names .

WireFormat.ReadDomainName should throw InvalidDataExecption for characters outside this range. For the time being, WireFormat.WriteDomainName show throw InvalidArgumentException.

PresentationFormat is not affected, because it can be UNICODE.

From https://tools.ietf.org/html/rfc1035#section-2.3.1

<label> ::= <letter> [ [ <ldh-str> ] <let-dig> ]

<ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>

<let-dig-hyp> ::= <let-dig> | "-"

<let-dig> ::= <letter> | <digit>

<letter> ::= any one of the 52 alphabetic characters A through Z in
upper case and a through z in lower case

<digit> ::= any one of the ten digits 0 through 9

Note that while upper and lower case letters are allowed in domain
names, no significance is attached to the case.  That is, two names with
the same spelling but different case are to be treated as if identical.

The labels must follow the rules for ARPANET host names.  They must
start with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen.  There are also some
restrictions on the length.  Labels must be 63 characters or less.

[richardschneider]

Domain labels now allow escaping.

[richardschneider]

It's been observed catalyst-network/Catalyst#630 that Apple uses UTF8 in domain names.

Change the domain name reader/writer to use UTF8 and not ASCII.