In DHCPv6-PD environment, where WAN interface requests IPv6 via DHCPv6,
receives the address as well as delegated prefixes, with LAN interfaces
serving those delegated prefixes in their router advertisement messages.
The LAN interfaces on the router themselves do not have
the IPv6 addresses assigned by networkd from the prefix it
serves on that interface. Now this patch enables it.
This allows users to configure a subnet id that should be used instead
of automatically (sequentially) assigned subnets. The previous attempt
had the downside that the subnet id would not be the same between
networkd restarts. In some setups it is desirable to have predictable
subnet ids across restarts of services and systems.
The code for the assignment had to be broken up into two pieces. One of
them is the old (sequential) assignment of prefixes and the other is the
new assignment based on configured subnet ids. The new assignment code
has to be executed first and has to be taken into account when (later
on) allocating the "old" subnets from the same pool.
Instead of having one iteration through the links we are now trying to
allocate a prefix for every link on every delegated prefix, unless they
received an assignment in a previous iteration.
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.
