Setting the MTU might fail when the underlying device's MTU
is not set.
Detect that case, and log a better warning message.
Unfortunately, it's tricky to detect whether this is a complete
failure, or whether we will later try again to change the MTU.
So, we log a failure, altough later we might fix it. It would
be better not to warn about non-errors.
and nm_utils_ip6_property_path(). The API with static buffers
looks a bit nicer. But I think they are dangerous, because
we tend to pass the buffer down several layers of the stack, and
it's not immediately clear, that we don't overwrite the static
buffer again (which we probably did not, but it's hard to verify
that there is no bug there).
Setting the MTU failes under regular conditions, for example when
setting the MTU of a master larger then the MTU of the slaves.
Logging a warning it too alarming.
Kernel does not allow setting the MTU of a VLAN larger
then the MTU of the underlying device. Hence, we might
initially fail to set a large MTU of the VLAN, but we
have to retry when the MTU of the parent changes.
https://bugzilla.redhat.com/show_bug.cgi?id=1414901
When comparing an unsigned and a signed integer, the signed integer
is promoted to unsigned, resulting in a very large number.
See the checks "nwrote < len - 1", where nwrote might be -1
to indicate failure. The condition would not be TRUE due to
promoting -1 to the max int value.
Hence, sysctl_set() was rather wrong.
In many scenarios, we have no use for the file descriptor
after nm_utils_fd_get_contents(). We just want to read it
and close it.
API wise, it would be nice that the get_contents() function never
closes the passed in fd and it's always responsibility of the caller.
However, that costs an additional dup() syscall that could
be avoided, if we allow the function to (optionally) close
the file descriptor.
The function should not close the input file descriptor; however
fdopen() associates the fd to the new stream so that when the stream
is closed, the fd is too. The result is a double close() and the
second call can in certain cases affect a wrong fd.
Use a duplicate fd for the stream.
Fixes: 1d9bdad1dfhttps://bugzilla.redhat.com/show_bug.cgi?id=1451236
libnm-core limits the rande for GATEWAY_PING_TIMEOUT to 0 to 600.
See commit e86f8354a7, "device: restart
ping process when it exits with an error".
The reader must not pass value out of range to g_object_set().
Clamp and warn.
"nm-dhcp-manager.h" forward declares _nm_dhcp_manager_factories.
We need to make the definition aware of the declaration, so
that the compiler can warn if they differ.
We don't need this extra distinguisher. It makes no sense to ever
compare two routes with a different compare-type.
Also, the number of fields that is hashed already differs between each
compare type. If we have a good hashing algorithm, this already suffices
that the hash value looks largely different.
We often want to cascade hashing, meaning, to combine the
outcome of various hash functions in a larger hash.
Instead of having each hash function return a guint hash value,
accept a hash state argument. This saves the overhead of initializing
and completing the intermediate hash states.
It also avoids loosing entropy when we reduce the larger hash state
into the intermediate guint hash value.
By using a macro, we don't cast all the types to guint. Instead,
we use their native types directly. Hence, we don't need
nm_hash_update_uint64() nor nm_hash_update_ptr().
Also, for types smaller then guint like char, we save hashing
the all zero bytes.
siphash24() is wildly used by projects nowadays.
It's certainly slower then our djb hashing that we used before.
But quite likely it's fast enough for us, given how wildly it is
used. I think it would be hard to profile NetworkManager to show
that the performance of hash tables is the issue, be it with
djb or siphash24.
Certainly with siphash24() it's much harder to exploit the hashing
algorithm to cause worst case hash operations (provided that the
seed is kept private). Does this better resistance against a denial
of service matter for us? Probably not, but let's better be safe then
sorry.
Note that systemd's implementation uses a different seed for each hash
table (at least, after the hash table grows to a certain size).
We don't do that and use only one global seed.
Replace the usage of g_str_hash() with our own nm_str_hash().
GLib's g_str_hash() uses djb2 hashing function, just like we
do at the moment. The only difference is, that we use a diffrent
seed value.
Note, that we initialize the hash seed with random data (by calling
getrandom() or reading /dev/urandom). That is a change compared to
before.
This change of the hashing function and accessing the random pool
might be undesired for libnm/libnm-core. Hence, the change is not
done there as it possibly changes behavior for public API. Maybe
we should do that later though.
At this point, there isn't much of a change. This patch becomes
interesting, if we decide to use a different hashing algorithm.
The privious NM_HASH_* macros directly operated on a guint value
and were thus close to the actual implementation.
Replace them by adding a NMHashState struct and accessors to
update the hash state. This hides the implementation better
and would allow us to carry more state. For example, we could
switch to siphash24() transparently.
For now, we still do a form basically djb2 hashing, albeit with
differing start seed.
Also add nm_hash_str() and nm_str_hash():
- nm_hash_str() is our own string hashing implementation
- nm_str_hash() is our own string implementation, but with a
GHashFunc signature, suitable to pass it to g_hash_table_new().
Also, it has this name in order to remind you of g_str_hash(),
which it is replacing.
"nm-utils/nm-shared-utils.h" shall contain utility function without other
dependencies. It is intended to be used by other projects as-is.
nm_utils_random_bytes() requires getrandom() and a HAVE_GETRANDOM configure
check. That makes it more cumbersome to re-use "nm-shared-utils.h", in
cases where you don't care about nm_utils_random_bytes().
Split nm_utils_random_bytes() out to a separate file.
Same for hash utils, which depend on nm_utils_random_bytes(). Also, hash
utils will eventually be extended to use siphash24.
Introduce a NM_HASH_INIT() function. It makes the places
where we initialize a hash with a certain seed visually clear.
Also, move them from "shared/nm-utils/nm-shared-utils.h" to
"shared/nm-utils/nm-macros-internal.h". We might want to
have NM_HASH_INIT() non-inline (hence, define it in the
source file).
Add a new function nm_utils_random_bytes().
This function now preferably uses getrandom() syscall if it is
available.
As fallback, it always tries to fill the buffer from /dev/urandom.
If it cannot, as last fallback it uses GRand, which cannot fail.
Hence, the function always sets some (pseudo) random bytes.
It also returns FALSE if the obtained bytes are possibly not good
randomness.
For routes and the default-route from NDisc, set the router preference
RTA_PREF.
Also, previously, we would only configure one IPv6 default-route. That by itself
was not really a problem, as long as NetworkManager would always make sure that
it configured the route to the ~best~ router.
Actually, NM should have done that already. It keeps the list of gateways
sorted, and prefers them according to their preference. But maybe
it didn't, so we have bug rh#1445417 (??).
Change that by configuring a default-route for all gateways, with
appropriate router prefrence. In case, kernel doesn't support RTA_PREF
yet, only configure all routes that share the same maxiumum preference.
https://bugzilla.redhat.com/show_bug.cgi?id=1445417
- add assert code to check that our internal tracking of
the gateways is consistent.
- assert (gracefully) against libndp returning :: as gateway
address.
We encounter the same enum in 3 forms:
- NMNDiscPreference in NetworkManager
- "enum ndp_route_preference" in <ndp.h>
- ICMPV6_ROUTER_PREF_* in <linux/icmpv6.h>
Move our enum to nm-core-utils.h, so that it can be used
by platform code as well (platform code should not include
ndisc/nm-ndisc.h).
Also, NMNDiscPreference was not numerically identical to their
native values (meaning: it shuffled the names and numbers).
Make them all numerically equal, so that they can be used in
the same context.
This means, while previously we could compare NMNDiscPreference
directly according to their priority, we now need _preference_to_priority().
On the other hand, we could omit translate_preference() -- but actually,
we still have _route_preference_coerce() because pref comes from libndp
and is thus untrusted. We still have to range check it.
We have the timestamp nm_utils_get_monotonic_time_s(), which should be
gint32 type. Then we also have timestamps in the NMNDisc* objects, which
consist of guint32 timestamp and lifetime.
Cleanup handling the times and calculation of the timestamps by using
the correct integer type consistently and ensuring that no integer overflow
occurs.
The @i variable to loop over the arrays should have the same type as
GArray.len, to which it is compared. In this case "guint".
As we remove items from the arrays while iterating over it, it gets
a bit complicated either way. I disliked that
g_array_remove_index (rdata->gateways, i--);
would underflow for unsigned integers. While that would work fine,
I think that is confusing. So, the variable is no longer incremented
in the increment statement of the for loop.
The bus manager takes extra references to the GDBusConnection every
time g_dbus_object_manager_server_get_connection() its called,
preventing its disposal once the connection is closed. This causes a
leak for each DHCP event.
https://bugzilla.redhat.com/show_bug.cgi?id=1461643
Before commit 650a7022c1, we would
always forego using getrandom(). That changed, and now we detect
at compile time whether getrandom() is provided by libc. So, if you
build against recent libc, we use it too.
However, systemd's src/basic/missing_syscall.h also provides getrandom() by
calling the syscall directly. We don't do that, because it seems too cumbersome
to maintain.
Fixes: 650a7022c1
Instead of having 3 properties @gateway, @never_default and @has_gateway
on NMIP4Config/NMIP6Config that determine the default-route, track the
default-route as a regular route.
The gateway setting is the configuration knob for the default-route.
Since an NMIP4Config/NMIP6Config instance only has one gateway property,
it cannot track more then one default-routes (see related bug rh#1445417).
Especially with policy routing, it might be interesting to configure a
default-route in multiple tables.
Also, later it might be interesting to allow adding default-routes as
regular static routes in a connection, so that the user can configure additional
route parameters for the default-route or add default-routes in multiple tables.
With this patch, default-routes now have a rt_source property according to their
origin.
Also, the previous commits of this branch broke handling of the
default-route :) . That should be working now again.
