Use dedicated multi->dco_peer_id for DCO instead of multi->peer_id

Use dedicated multi->dco_peer_id for DCO instead of multi->peer_id

The lifetime and state machine of multi->peer_id does not exactly the
lifetime/state of DCO. This is especially for p2p NCP where a reconnection
can change the peer id. Also use this new field with value -1 to mean
not installed, replacing the dco_peer_added field.

Also ensure that we have a failure adding a new peer, we don't try to
set options for that peer or generating keys for it.

Patch v2: fix one comparison checking for 0 instead of -1
Patch v3: make recovery after failing dco_add_peer more robust
          and the comparison that lead to not deleting a peer.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20221127090742.3487997-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/search?l=mid&q=20221127090742.3487997-1-arne@rfc2549.org
Signed-off-by: Gert Doering <gert@greenie.muc.de>