For WireGuard (like for all IP-tunnels and IP-based VPNs), the IP addresses of
the peers must be reached outside the tunnel/VPN itself.
For VPN connections, NetworkManager usually adds a direct /32 route to
the external VPN gateway to the underlying device. For WireGuard that is
not done, because injecting a route to another device is ugly and error
prone. Worse: WireGuard with automatic roaming and multiple peers makes this
more complicated.
This is commonly a problem when setting the default-route via the VPN,
but there are also other subtle setups where special care must be taken
to prevent such routing loops.
WireGuard's wg-quick provides a simple, automatic solution by adding two policy
routing rules and relying on the WireGuard packets having a fwmark set (see [1]).
Let's also do that. Add new properties "wireguard.ip4-auto-default-route"
and "wireguard.ip6-auto-default-route" to enable/disable this. Note that
the default value lets NetworkManager automatically choose whether to
enable it (depending on whether there are any peers that have a default
route). This means, common scenarios should now work well without additional
configuration.
Note that this is also a change in behavior and upon package upgrade
NetworkManager may start adding policy routes (if there are peers that
have a default-route). This is a change in behavior, as the user already
clearly had this setup working and configured some working solution
already.
The new automatism picks the rule priority automatically and adds the
default-route to the routing table that has the same number as the fwmark.
If any of this is unsuitable, then the user is free to disable this
automatism. Note that since 1.18.0 NetworkManager supports policy routing (*).
That means, what this automatism does can be also achieved via explicit
configuration of the profile, which gives the user more flexibility to
adjust all parameters explicitly).
(*) but only since 1.20.0 NetworkManager supports the "suppress_prefixlength"
rule attribute, which makes it impossible to configure exactly this rule-based
solution with 1.18.0 NetworkManager.
[1] https://www.wireguard.com/netns/#improved-rule-based-routing
Changing "ipv4.route-table" and "ipv6.route-table" was not allowed
during reapply.
The main difficulty for supporting that is changing the sync-mode.
With route-table 0, we don't sync all tables but only the main table.
So, when reapply changes from full-sync to no-full-sync, it's slightly
more complicated.
But it's probably not too complicated either. The change from
no-full-sync to full-sync is simple: we just start doing a full-sync.
The reverse change is slightly more complicated, because we need to
do one last full-sync, to get rid of routes that we configured on those
other tables.
From the files under "shared/nm-utils" we build an internal library
that provides glib-based helper utilities.
Move the files of that basic library to a new subdirectory
"shared/nm-glib-aux" and rename the helper library "libnm-core-base.la"
to "libnm-glib-aux.la".
Reasons:
- the name "utils" is overused in our code-base. Everything's an
"utils". Give this thing a more distinct name.
- there were additional files under "shared/nm-utils", which are not
part of this internal library "libnm-utils-base.la". All the files
that are part of this library should be together in the same
directory, but files that are not, should not be there.
- the new name should better convey what this library is and what is isn't:
it's a set of utilities and helper functions that extend glib with
funcitonality that we commonly need.
There are still some files left under "shared/nm-utils". They have less
a unifying propose to be in their own directory, so I leave them there
for now. But at least they are separate from "shared/nm-glib-aux",
which has a very clear purpose.
(cherry picked from commit 80db06f768)
A NetworkManager client requires an API to validate and decode
a base64 secret -- like it is used by WireGuard. If we don't have
this as part of the API, it's inconvenient. Expose it.
Rename it from _nm_utils_wireguard_decode_key(), to give it a more
general name.
Also, rename _nm_utils_wireguard_normalize_key() to
nm_utils_base64secret_normalize(). But this one we keep as internal
API. The user will care more about validating and decoding the base64
key. To convert the key back to base64, we don't need a public API in
libnm.
This is another ABI change since 1.16-rc1.
(cherry picked from commit e46ba01867)
That is slightly complex, because we need to (DNS) resolve the endpoints,
and we also have to retry periodically. For example, initially we may be
unable to resolve an endpoint, but later we may be.
What is also interesting is that during assume and reapply, we may not
have all information in the profile. Most notably, the private keys will
be missing. We need to cope with that and not reconfigure keys. However,
we still need to resolve names and update the endpoints.
For now only add the core settings, no peers' data.
To support peers and the allowed-ips of the peers is more complicated
and will be done later. It's more complicated because these are nested
lists (allowed-ips) inside a list (peers). That is quite unusual and to
conveniently support that in D-Bus API, in keyfile format, in libnm,
and nmcli, is a effort.
Also, it's further complicated by the fact that each peer has a secret (the
preshared-key). Thus we probably need secret flags for each peer, which
is a novelty as well (until now we require a fixed set of secrets per
profile that is well known).
