This patch adds a missing docstrings for exported identifiers, and
adjust some of the existing ones to match the standard style.
In some cases, the identifiers were un-exported after noticing they had
no external users.
Besides improving documentation, it also reduces the linter noise
significantly.
The right-hand side addresses of an alias should be normalized, to
maintain the internal invariant that we always deal with normalized
addresses.
Otherwise, strange situations may arise, such as the same domain having
two different domaininfo structures depending on case.
This patch is the result of running go vet, go fmt -s and the linter,
and fixing some of the things they noted/suggested.
There shouldn't be any significant logic changes, it's mostly
readability improvements.
This patch implements local username normalization using PRECIS
(https://tools.ietf.org/html/rfc7564,
https://tools.ietf.org/html/rfc7613)
It makes chasquid accept local email and authentication regardless of
the case. It covers both userdb and aliases.
Note that non-local usernames remain untouched.
It's more convenient and in line with standard practice to fail RCPT TO if the
user does not exist.
This involves making the server and client aware of aliases, but it doesn't
end up being very convoluted, and simplifies other code.
Today, if the aliases file does not exist when chasquid starts up, the entire
domain will be skipped from aliases resolution.
That's a bug, as it means we don't perform character and suffix replacements
for known domains, and is also an inconvenience as it forces us to reload the
daemon when adding a file for a known domain.
This patch fixes this by adding them unconditionally, even if the file does
not exist.
This patch removes chasquid-userdb and adds a more generic and extensive
chasquid-util, that supports various operations on user databases as well as
aliases lookups.
The code is not very pretty but for now I took a more practical approach, the
tool is ancillary and can be tidied up later.
aliases databases can be very useful, so this patch adds a package to parse
and resolve aliases.
It uses an existing, well known and widely used format for aliases, although
it doesn't necessarily match 100% any existing implementation at the moment.
