All those uses were correct, but I think it's better to be explicit.
Using implicit errno is too error prone, and with this change we can require
(in the sense of a style guideline) that the code is always specified.
Helpful query: git grep -n -P 'log_[^s][a-z]+\(.*%m'
This changes the return value a bit: 1 will be returned if the value is
changed. But the return value was not documented, and the change should
be for the good anyway. Current callers don't care.
assert_return() should only be used to validate user-facing parameters and
state, assert() should be used for checking our own internal state and
parameters.
A field "index" is not particularly precise and also might conflict with libc's
index() function definition. Also, pretty much everywhere else we call this
concept "ifindex", including in networkd, the primary user of these libraries.
Hence, let's fix this up and call this "ifindex" everywhere here too.
According to recv(2) these should be the same, but that is not true.
Passing a buffer of length 0 to read is defined to be a noop according
to read(2), but passing a buffer of length 0 to recv will discard the
pending pacet.
We can easily hit this as we allocate our buffer size depending on
the size of the incoming packet (using FIONREAD). As pointed out in
issue #3299 simply sending an empty UDP packet to the DHCP client
port will trigger a busy loop in networkd as we are polling on the
socket but never discarding the empty packet.
This reverts ad5ae47a0d but fixes the
same issue.
Both versions of the code are changed to allow the caller to override
DUID using simple rules: duid type and value may be specified, in
which case the caller is responsible to providing the contents,
or just duid type may be specified as DUID_TYPE_EN, in which case we
we fill in the values. In the future more support for other types may
be added, e.g. DUID_TYPE_LLT.
There still remains and ugly discrepancy between dhcp4 and dhcp6 code:
dhcp6 has sd_dhcp6_client_set_duid and sd_dhcp6_client_set_iaid and
requires client->state to be DHCP6_STATE_STOPPED, while dhcp4 has
sd_dhcp_client_set_iaid_duid and will reconfigure the client if it
is not stopped. This commit doesn't touch that part.
This addresses #3127 § 2.
Initialize auto variables with cleanup attribute, otherwise we
get a compiler warning with -fexceptions.
./configure CFLAGS='-Wmaybe-uninitialized -fexceptions -O2'
The server might answer to a DHCPREQUEST with a NAK and currently the
client restarts the configuration process immediately. It was
observed that this can easily generate loops in which the network is
flooded with DISCOVER,OFFER,REQUEST,NAK sequences.
RFC 2131 only states that "if the client receives a DHCPNAK message,
the client restarts the configuration process" without further
details.
Add a delay with exponential backoff between retries after NAKs to
limit the number of requests and cap the delay to 30 minutes.
libsystemd-network provides the public function
sd_dhcp_client_set_request_option() to enable the request of a given
DHCP option. However the enum defining such options is defined in the
internal header dhcp-protocol.h. Move the enum definition to the
public header sd-dhcp-client.h and properly namespace values.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
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().
If a client sends a DECLINE or a server sends a NAK, they can include
a string with a message to explain the error. Parse this and print it
at debug level.
This adds support for the Client Fully Qualified Domain Name (FQDN)
option [RFC 4702] to libsystemd-network. The option can be used to
exchange information about a DHCPv4 client's fully qualified domain
name and about responsibility for updating the DNS RR related to the
client's address assignment.
Other popular DHCP clients (dhclient, dhcpcd) support this option and
it would be useful to have it in networkd too.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
a) drop handling of obsolete or unused DHCP options time_offset,
mtu_aging_timeout, policy filter, mdr, ttl, ip forwarding settings.
Should this become useful one day we can readd support for this.
b) For subnet mask and broadcast it is not always clear whether 0 or
255.255.255.255 might be valid, hence maintain a boolean indicating
validity next to it.
c) serialize/deserialize broadcast address, lifetime, T1 and T2 together
with the rest of the fields in dhcp_lease_save() and
dhcp_lease_load().
d) consistently return ENODATA from getter functions for data that is
missing in the lease.
e) add missing getter calls for broadcast, lifetime, T1, T2.
f) when decoding DHCP options, generate debug messages on parse
failures, but try to proceed if possible.
g) Similar, when deserializing a lease in dhcp_lease_load(), make sure
we deal nicely with unparsable fields, to provide upgrade compat.
h) fix some memory allocations
In our API design, getter-functions don't ref objects. Calls like
foo_get_bar() will not ref 'bar'. We never do that and there is no real
reason to do it in single threaded APIs. If you need a ref-count, you
better take it yourself *BEFORE* doing anything else on the parent object
(as this might invalidate your pointer).
Right now, sd_dhcp?_get_lease() refs the lease it returns. A lot of
code-paths in systemd do not expect this and thus leak the lease
reference. Fix this by changing the API to not ref returned objects.
