Hi,
On Wed, 9 Mar 2022 15:28:44 +0900
Yuichiro NAITO <naito.yuich...@gmail.com> wrote:
> I see 'Address already in use' message,
> when I change wgrtable for a running wg interface.
> It doesn't make sense to me.
>
> It can be reproduced by the following command sequence.
>
> ```
> # route -T1 add default `cat /etc/mygate`
> # ifconfig wg0 create wgport 7111 wgkey `cat /etc/mykey.wg0`
> # ifconfig wg0 up
> # ifconfig wg0 wgrtable 1
> ifconfig: SIOCSWG: Address already in use
> ```
>
> When I down wg0 interface before changing wgrtable,
> It succeeds and no messages are shown.
>
> I investigated the reason why 'Address already in use' is shown.
>
> If wgrtable is specified by ifconfig argument,
> `wg_ioctl_set` function in `sys/net/if_wg.c` is called.
>
> And if the wg interface is running, `wg_bind` function is called.
> `wg_bind` creates new sockets (IPv4 and 6) and replace them from old
> ones.
>
> If only wgrtable is changed, `wg_bind` binds as same port as existing
> sockets.
> So 'Address already in use' is shown.
>
> Here is a simple patch to close existing sockets before `wg_bind`.
> It works for me but I'm not 100% sure this is right fix.
>
> Any other ideas?
>
> ```
> diff --git a/sys/net/if_wg.c b/sys/net/if_wg.c
> index 4dae3e3c976..0159664fb34 100644
> --- a/sys/net/if_wg.c
> +++ b/sys/net/if_wg.c
> @@ -2253,11 +2253,14 @@ wg_ioctl_set(struct wg_softc *sc, struct
> wg_data_io *data)
> if (port != sc->sc_udp_port || rtable != sc->sc_udp_rtable) {
> TAILQ_FOREACH(peer, &sc->sc_peer_seq, p_seq_entry)
> wg_peer_clear_src(peer);
>
> - if (sc->sc_if.if_flags & IFF_RUNNING)
> + if (sc->sc_if.if_flags & IFF_RUNNING) {
> + if (port == sc->sc_udp_port)
> + wg_unbind(sc);
> if ((ret = wg_bind(sc, &port, &rtable)) != 0)
> goto error;
> + }
>
> sc->sc_udp_port = port;
> sc->sc_udp_rtable = rtable;
> }
> ```
If rdomain 1 exists, the error will not shown.
# ifconfig vether0 rdomain 1 up
# ifconfig wg0 create wgport 7111 wgkey `openssl rand -base64 32` up
# ifconfig wg0 wgrtable 1
#
In the case which you reported to, it is supposed that rtable 1 exists
but rdomain 1 doesn't exist.
Even when "wgtable 1" is configured, becase there is no dedicated
rdomain, rdomain 0 will be used to bind the UDP port.
So what wg(4) should do for this case is "nothing".
So the diff is updated.
ok?
Index: sys/net/if_wg.c
===================================================================
RCS file: /disk/cvs/openbsd/src/sys/net/if_wg.c,v
retrieving revision 1.22
diff -u -p -r1.22 if_wg.c
--- sys/net/if_wg.c 22 Feb 2022 01:15:02 -0000 1.22
+++ sys/net/if_wg.c 27 Mar 2022 09:17:08 -0000
@@ -2250,7 +2250,8 @@ wg_ioctl_set(struct wg_softc *sc, struct
else
rtable = sc->sc_udp_rtable;
- if (port != sc->sc_udp_port || rtable != sc->sc_udp_rtable) {
+ if (port != sc->sc_udp_port ||
+ rtable_l2(rtable) != sc->sc_udp_rtable) {
TAILQ_FOREACH(peer, &sc->sc_peer_seq, p_seq_entry)
wg_peer_clear_src(peer);
