Multicast snooping enabled bridges maintain a database for multicast
port memberships to decide which mulicast packet is supposed to
egress on which port.
This patch teaches networkd to add entries to this database manually
by adding `[BridgeMDB]` sections to `.network` configuration files.
When 4dfaa528d4 was first commited its callers relied on `errno` instead of the
return value for error reporting. Which worked fine, since internally
under all conditions base were set — even if ugly and not inline with
our coding style. Things then got broken in
f8606626ed where suddenly additional
syscalls might end up being done in the function, thus corrupting `errno`.
Two functional changes:
- "/" is now refused. The test is adjusted.
- The trailing NUL is *not* included in the returned size for abstract size. The
comments in sockaddr_un_set_path() indicate that this is the right thing to do,
and the code in socket_address_parse() wasn't doing that.
Closes#12624.
The formatting in systemd.socket.xml is updated a bit.
Currently in_addr_port_ifindex_name_to_string() always prints the ifindex
numerically. This is not super useful since the interface numbers are
semi-random. Should we use interface names in preference?
We would set .type to a fake value. All real callers (outside of tests)
immediately overwrite .type with a proper value after calling
socket_address_parse(). So let's not set it and adjust the few places
that relied on it being set to the fake value.
socket_address_parse() is modernized to only set the output argument on
success.
One special syntax is not supported anymore: "iface:port" would be parsed as an
interface name plus numerical port, equivalent to "[::]%iface:port". This was
added in 542563babd, but was undocumented, and we had no tests for it. It seems
that this actually wasn't doing anything useful, because the kernel only uses the
scope identifier for link-local addresses.
We don't try to resolve invalid ifnames as all. A different return
code is used. This difference will be verified later in test_socket_address_parse()
when socket_address_parse() is converted to use
in_addr_port_ifindex_name_from_string_auto().
lichangze