Previously we'd only store the DnsPacket in the DnsTransaction, and the
DnsQuery would then take the DnsPacket's DnsAnswer and return it. With
this change we already pull the DnsAnswer out inside the transaction.
We still store the DnsPacket in the transaction, if we have it, since we
still need to determine from which peer a response originates, to
implement caching properly. However, the DnsQuery logic doesn't care
anymore for the packet, it now only looks at answers and rcodes from the
successfuly candidate.
This also has the benefit of unifying how we propagate incoming packets,
data from the local zone or the local cache.
Let's use a more useful way to write the flags. Also, leave some space
in the middle for the mDNS flags. After all, these flags are exposed on
the bus, and we should really make sure to expose flags that are going
to be stable, hence allow some room here...
(Not that the room really mattered, except to be nice to one's OCD)
It may be unexpected to find a CNAME record when doing a reverse lookup, as we
expect to find a PTR record directly. However, it is explicitly supported
according to <https://tools.ietf.org/html/rfc2181#section-10.2>, and there
seems to be no benefit to not supporting it.
The assumption that no NSEC bitmap could be empty due to the presence of the bit representing
the record itself turns out to be flawed. See (the admittedly experimental) RFC4956 for a
counter example.
The new dns_label_escape() call now operates on a buffer passed in,
similar to dns_label_unescape(). This should make decoding a bit faster,
and nicer.
Let's change the return value to bool. If we encounter an error while
parsing, return "false" instead of the actual parsing error, after all
the specified hostname does not qualify for what the function is
supposed to test.
Dealing with the additional error codes was always cumbersome, and
easily misused, like for example in the DHCP code.
Let's also rename the functions from dns_name_root() to
dns_name_is_root(), to indicate that this function checks something and
returns a bool. Similar for dns_name_is_signal_label().
This adds support for searching single-label hostnames in a set of
configured search domains.
A new object DnsQueryCandidate is added that links queries to scopes.
It keeps track of the search domain last used for a query on a specific
link. Whenever a host name was unsuccessfuly resolved on a scope all its
transactions are flushed out and replaced by a new set, with the next
search domain appended.
This also adds a new flag SD_RESOLVED_NO_SEARCH to disable search domain
behaviour. The "systemd-resolve-host" tool is updated to make this
configurable via --search=.
Fixes#1697
For now, let's just expose the LLMNR hostname currently in use; a
combined list of all dns servers with their interface indexes; a
combined list of all search domains with their interface indexes.
This copies concepts we introduced for the DnsSearchDomain stuff, and
reworks the operations on lists of dns servers to be reusable and
generic for use both with the Link and the Manager object.
With this change, we add a new object to resolved, "DnsSearchDomain="
which wraps a search domain. This is then used to introduce a global
search domain list, in addition to the existing per-link search domain
list which is reword to make use of this new object too.
This is preparation for implement proper unicast DNS search domain
support.
Previously, we'd keep adding new dns servers we discover to the end of
our linked list of servers. When we encountered a pre-existing server,
we'd just leave it where it was. In essence that meant that old servers
ended up at the front, and new servers at the end, but not in an order
that would reflect the configuration.
With this change we ensure that every pre-existing server we want to add
again we move to the back of the linked list, so that the order is
stable and in sync with the requested configuration.
Previously, there was a chance of memory corruption, because when
switching to the next DNS server we didn't care whether they linked list
of DNS servers was still valid.
Clean up lifecycle of the dns server logic:
- When a DnsServer object is still in the linked list of DnsServers for
a link or the manager, indicate so with a "linked" boolean field, and
never follow the linked list if that boolean is not set.
- When picking a DnsServer to use for a link ot manager, always
explicitly take a reference.
This also rearranges some logic, to make the tracking of dns servers by
link and globally more alike.
Let's use the same parser when parsing dns server information from
/etc/resolv.conf and our native configuration file.
Also, move all code that manages lists of dns servers to a single place.
resolved-dns-server.c
Wen DnsQuestion objects are used for DnsQuery objects all contained keys
have to share the same name, but otherwise they generally don't have to,
and this can actually happen in real-life because DnsPacket objects for
mDNS use DnsQuestion for the question section.
Hence, rename:
dns_question_is_valid() to dns_question_is_valid_for_query(), since the
name uniqueness check it does is only relevant when used for a query.
Similar, rename dns_question_name() to dns_question_first_name(),
to be more accurate, as this difference matters if we keys don#t have to
share the same name.
Commit 5e5b137a (networkd: link - drop foreign config when configuring
link) introduced a regression where addresses (including 127.0.0.1) are
removed from loopback device.
Do not handle loopback device when removing foreign configs.
Signed-off-by: Christian Hesse <mail@eworm.de>
The new parser supports:
<value> - specify both limits to the same value
<soft:hard> - specify both limits
the size or time specific suffixes are supported, for example
LimitRTTIME=1sec
LimitAS=4G:16G
The patch introduces parse_rlimit_range() and rlim type (size, sec,
usec, etc.) specific parsers. No code is duplicated now.
The patch also sync docs for DefaultLimitXXX= and LimitXXX=.
References: https://github.com/systemd/systemd/issues/1769
This also adds client-side support for this to systemd-resolve-host.
Note that the ResolveService() API can deal both with DNS-SD service
(consisting of service name, type and domain), as well as classic SRV
services (consisting just of a type and a domain), all exposed in the
same call.
This patch also reworks CNAME handling in order to reuse it between
hostname, RR and service lookups.
In contrast to Avahi and Bonjour, this new API will actually reolve the
A/AAAA RRs the SRV RRs point to in one go (unless this is explicitly
disabled). This normally comes for free, as these RRs are sent along
the SRV responses anyway, hence let's make use of that. This makes the
API considerably easier to use, as a single ResolveService() invocation
will return all necessary data to pick a server and connect() to it.
Note that this only implements the DNS-SD resolving step, it does not
implement DNS-SD browsing, as that makes sense primarily on mDNS, due to
its continuous nature.
This adds dns_service_join() and dns_service_split() which may be used
to concatenate a DNS-SD service name, am SRV service type string, and a
domain name into a full resolvable DNS domain name string. If the
service name is specified as NULL, only the type and domain are
appended, to implement classic, non-DNS-SD SRV lookups.
The reverse is dns_service_split() which takes the full name, and split
it into the three components again.
RFC 6763 is very clear that TXT RRs should allow arbitrary binary
content, hence let's actually accept that. This also means accepting NUL
bytes in the middle of strings.
Virtualbox should be detected as 'oracle'. This used to work but broke
with commit:
commit 75f86906c5
Author: Lennart Poettering <lennart@poettering.net>
Date: Mon Sep 7 13:42:47 2015 +0200
basic: rework virtualization detection API
We swap detection for dmi and cpuid, this fixes Virtualbox with KVM.
Hopefully it does not break anything else.
