Otherwise, changing the default gateway doesn't purge old gateway routes
left on the system during daemon restart. This also fixes removing other
foreign gateway routes that don't match the expected configuration.
Tested:
Changed gateway addresses prior to the patch and they lingered on
the system during each reconfiguration. Applied this patch and
reconfigured gateways and other routes multiple times and it removed
the foreign routes that had gateways that didn't match.
Signed-off-by: William A. Kennington III <william@wkennington.com>
The flag IFA_F_NOPREFIXROUTE was introduced in kernel-3.14. But even if
the kernel does not support the flag, it should be just ignored. So, it
is not necessary to do the fallback logic. Moreover, the current logic
is not a fallback mechanism but just retrying. So, it should not work.
Let's drop that.
Some path of configuring address, route or etc., go to failed state, but
some do not. E.g., failure in address configuration which is provided by
DHCPv4 goes to failed state, but static address does not.
This is just for consistency. This should not change anything if
everything is fine.
This also voidify manager_rtnl_process_address().
The function sd_radv_add_prefix() in dhcp6_pd_prefix_assign() may
return -EEXIST, and in that case the sd_radv_prefix object allocated
in dhcp6_pd_prefix_assign() will be freed when the function returns.
Hence, the key value in Manager::dhcp6_prefixes hashmap is lost.
Found by inspecting results of running this small program:
int main(int argc, const char **argv) {
for (int i = 1; i < argc; i++) {
FILE *f;
char line[1024], prev[1024], *r;
int lineno;
prev[0] = '\0';
lineno = 1;
f = fopen(argv[i], "r");
if (!f)
exit(1);
do {
r = fgets(line, sizeof(line), f);
if (!r)
break;
if (strcmp(line, prev) == 0)
printf("%s:%d: error: dup %s", argv[i], lineno, line);
lineno++;
strcpy(prev, line);
} while (!feof(f));
fclose(f);
}
}
An earlier commit 0e408b82b (dhcp6-client: handle IAID with value zero)
introduced a flag to sd_dhcp6_client to distinguish between an unset
IAID and a value set to zero.
However, that was not sufficient and broke leaving the setting
uninitialized in networkd configuration. The configuration parsing
also must distinguish between the default, unset value and an
explict zero configuration.
Fixes: 0e408b82b8
Request prefix delegation for a new downstream link that is enabled
after any number of upstream DHCPv6 links. Submit the request after
the link has been configured with a link-local address.
If the upstream DHCPv6 client has already been configured to request
prefixes, attempt to re-assign any possible prefixes between the
already existing links and the new one. If no prefixes are yet
acquired, nothing will happen right away and any prefixes will be
distributed after a reply from the DHCPv6 server.
If none of the already existing downstream links have requested
DHCPv6 prefixes to be assigned, enable prefix delegation for each
client and restart them one by one if they are already running. This
causes the DHCPv6 clients to re-acquire addresses and prefixes and
to re-distribute them to all links when receiving an updated
response from their respective DHCPv6 servers. If the DHCPv6 client
in question was not already running, it is set to request prefixes
but not restarted.
When an error occurs while setting or restarting the DHCPv6 client,
log the incident and move over to the next link.
Fixes#9758.
Start with route set to NULL should there be no route created. Remove
the explicit route_free as the _cleanup_ will take care of that after
the continue;.
In order to shut down networkd properly, the delegated routes added
need to be removed properly, and as error reporting is wanted, the
network link is needed in the debug output.
Solve this by calling manager_dhcp6_prefix_remove_all(), which will
remove each prefix stored in the Manager structure, and while doing
that reference each link so that it isn't freed before the route
removal callback is called. This in turn causes the network link to
be referenced once more, and an explicit hashmap_remove() must be
called to remove the network link from the m->links hashmap.
Also, since the registered callback is not called when the DHCPv6
client is stopped with sd_dhcp6_client_stop(), an explicit call
to dhcp6_lease_pd_prefix_lost() needs to be made to clean up any
unreachable routes set up for the delegated prefixes.
Instead of setting many small unreachable routes for each of the /64
subnets that were not distributed between the links requesting delegated
prefixes, set one unreachable route for the size of the delegated
prefix. Each subnet asssigned to a downstream link will add a routable
subnet for that link, and as the subnet assigned to the downstream link
has a longer prefix than the whole delegated prefix, the downstream
link subnet routes are preferred over the unroutable delegated one.
The unreachable route is not added when the delegated prefix is exactly
a /64 as the prefix size cannot be used to sort out the order of routing
into a bigger blocking subnet with the smaller /64 punching routable
"holes" into it.
When stopping the DHCPv6 client, the unroutable delegated prefix is
removed before the downstream link prefixes are unassigned.
RFC 7084, WPD-4, requires Customer Edge end routers to behave
according to the following:
"WPD-4: By default, the IPv6 CE router MUST initiate DHCPv6 prefix
delegation when either the M or O flags are set to 1 in a
received Router Advertisement (RA) message. Behavior of the
CE router to use DHCPv6 prefix delegation when the CE router
has not received any RA or received an RA with the M and the
O bits set to zero is out of scope for this document."
Since it cannot be automatically detected whether DHCPv6 is to be
operated as an CE end router or whether to initiate an Informational
exchange to obtain other useful network information via DHCPv6 when the
Router Advertisement 'O' bit is set, a 'ForceDHCPv6PDOtherInformation'
boolean network configuration option in the '[DHCP]' section of a is
introduced. Setting this option causes DHCPv6 to be started in stateful
mode, although only the 'O' bit is seen in the Router Advertisement.
When 'ForceDHCPv6PDOtherInformation' is set and the Router Advertisement
has only the Other information 'O' bit set, disable requests for IA_NA
addresses.
Fixes#9745.
When computing the next network prefix to assign, compute the next
prefix to allocate based on the intended /64 assignment, not the
given prefix length for the whole prefix, e.g. /48, given to
systemd-networkd.
Fixes#9626.
