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authorMatthew Smith <mgsmith@netgate.com>2020-07-24 13:38:03 -0500
committerMatthew Smith <mgsmith@netgate.com>2020-11-05 17:41:01 +0000
commitbd50ed18de83493b119e67897a5fa9ba9c7e763e (patch)
tree6cce31f5795f25c34bf7badfbfec5152a3d67ca0 /src/vnet/devices/tap/tap.c
parentd4a547144ffc0f68538d5a89ce7d41cd739a33d2 (diff)
tap: allow change of carrier state on host
Type: feature Add a function to adjust the link state of the host side of a tap interface. If an application (e.g. route protocol daemons) running on the host uses netlink to monitor interface state, a plugin could use this function to communicate a loss of connectivity to the application by making the interface appear to go down. Requires a somewhat recent kernel. E.g. it does not have any effect on CentOS 7 but it works on CentOS 8. Change-Id: I677ee7889d2eb142e2395bea98f0b4d7e7e7f810 Signed-off-by: Matthew Smith <mgsmith@netgate.com>
Diffstat (limited to 'src/vnet/devices/tap/tap.c')
-rw-r--r--src/vnet/devices/tap/tap.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/src/vnet/devices/tap/tap.c b/src/vnet/devices/tap/tap.c
index aa9182a58f7..94a91e5509a 100644
--- a/src/vnet/devices/tap/tap.c
+++ b/src/vnet/devices/tap/tap.c
@@ -751,6 +751,12 @@ tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
vif->flags |= VIRTIO_IF_FLAG_ADMIN_UP;
vnet_hw_interface_set_flags (vnm, vif->hw_if_index,
VNET_HW_INTERFACE_FLAG_LINK_UP);
+ /*
+ * Host tun/tap driver link carrier state is "up" at creation. The
+ * driver never changes this unless the backend (VPP) changes it using
+ * TUNSETCARRIER ioctl(). See tap_set_carrier().
+ */
+ vif->host_carrier_up = 1;
vif->cxq_vring = NULL;
goto done;
@@ -987,6 +993,41 @@ tap_dump_ifs (tap_interface_details_t ** out_tapids)
return 0;
}
+/*
+ * Set host tap/tun interface carrier state so it will appear to host
+ * applications that the interface's link state changed.
+ *
+ * If the kernel we're building against does not have support for the
+ * TUNSETCARRIER ioctl command, do nothing.
+ */
+int
+tap_set_carrier (u32 hw_if_index, u32 carrier_up)
+{
+ int ret = 0;
+#ifdef TUNSETCARRIER
+ vnet_main_t *vnm = vnet_get_main ();
+ vnet_hw_interface_t *hi = vnet_get_hw_interface (vnm, hw_if_index);
+ virtio_main_t *mm = &virtio_main;
+ virtio_if_t *vif;
+ int *fd;
+
+ vif = pool_elt_at_index (mm->interfaces, hi->dev_instance);
+ vec_foreach (fd, vif->tap_fds)
+ {
+ ret = ioctl (*fd, TUNSETCARRIER, &carrier_up);
+ if (ret < 0)
+ {
+ clib_warning ("ioctl (TUNSETCARRIER) returned %d", ret);
+ break;
+ }
+ }
+ if (!ret)
+ vif->host_carrier_up = (carrier_up != 0);
+#endif
+
+ return ret;
+}
+
static clib_error_t *
tap_mtu_config (vlib_main_t * vm, unformat_input_t * input)
{