To be able to configure a FreeBSD interface to "subnet" mode
(as opposed to point-to-point mode), it needs to have its
if_iflags set to IFF_BROADCAST. For tun(4) interface this is
done with the TUNSIFMODE ioctl(), but this does not work for
more modern interfaces like ovpn(4) which communicate over
a common SIOCSDRVSPEC ioctl() that contains a "cmd" and a
"parameter list".
Introduce OVPN_SET_IFMODE cmd, add dco_set_ifmode() function
to put kernel interface into IFF_BROADCAST or IFF_POINTOPOINT
as needed.
(This needs a kernel patch to add the OVPN_SET_IFMODE on the
other side - with an older kernel, OpenVPN will just fail now)
Signed-off-by: Gert Doering <g...@greenie.muc.de>
---
src/openvpn/dco_freebsd.c | 36 ++++++++++++++++++++++++++++++++++
src/openvpn/ovpn_dco_freebsd.h | 1 +
2 files changed, 37 insertions(+)
diff --git a/src/openvpn/dco_freebsd.c b/src/openvpn/dco_freebsd.c
index c6da6ce3..8adbf7f1 100644
--- a/src/openvpn/dco_freebsd.c
+++ b/src/openvpn/dco_freebsd.c
@@ -165,6 +165,34 @@ ovpn_dco_init(int mode, dco_context_t *dco)
return true;
}
+static int
+dco_set_ifmode(dco_context_t *dco, int ifmode)
+{
+ struct ifdrv drv;
+ nvlist_t *nvl;
+ int ret;
+
+ msg(M_INFO, "ifmode=%08x", ifmode);
+ nvl = nvlist_create(0);
+ nvlist_add_number(nvl, "ifmode", ifmode);
+
+ CLEAR(drv);
+ snprintf(drv.ifd_name, IFNAMSIZ, "%s", dco->ifname);
+ drv.ifd_cmd = OVPN_SET_IFMODE;
+ drv.ifd_data = nvlist_pack(nvl, &drv.ifd_len);
+
+ ret = ioctl(dco->fd, SIOCSDRVSPEC, &drv);
+ if (ret)
+ {
+ msg(M_WARN | M_ERRNO, "Failed to set ifmode");
+ }
+
+ free(drv.ifd_data);
+ nvlist_destroy(nvl);
+
+ return ret;
+}
+
static int
create_interface(struct tuntap *tt, const char *dev)
{
@@ -205,6 +233,14 @@ create_interface(struct tuntap *tt, const char *dev)
snprintf(tt->dco.ifname, IFNAMSIZ, "%s", ifr.ifr_data);
tt->actual_name = string_alloc(tt->dco.ifname, NULL);
+ /* see "Interface Flags" in ifnet(9) */
+ int i = IFF_POINTOPOINT | IFF_MULTICAST;
+ if (tt->topology == TOP_SUBNET)
+ {
+ i = IFF_BROADCAST | IFF_MULTICAST;
+ }
+ dco_set_ifmode(&tt->dco, i);
+
return 0;
}
diff --git a/src/openvpn/ovpn_dco_freebsd.h b/src/openvpn/ovpn_dco_freebsd.h
index 7ceec06e..cf92d597 100644
--- a/src/openvpn/ovpn_dco_freebsd.h
+++ b/src/openvpn/ovpn_dco_freebsd.h
@@ -60,5 +60,6 @@ enum ovpn_key_cipher {
#define OVPN_SEND_PKT _IO('D', 9)
#define OVPN_POLL_PKT _IO('D', 10)
#define OVPN_GET_PKT _IO('D', 11)
+#define OVPN_SET_IFMODE _IO('D', 12)
#endif /* ifndef _NET_IF_OVPN_H_ */
--
2.37.3
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