@@ -171,7 +171,7 @@
* The ability of the backend to use a control ring is advertised by
* setting:
*
- * /local/domain/X/backend/<domid>/<vif>/feature-ctrl-ring = "1"
+ * /local/domain/X/backend/vif/<domid>/<vif>/feature-ctrl-ring = "1"
*
* The frontend provides a control ring to the backend by setting:
*
@@ -190,6 +190,20 @@
* order as requests.
*/
+/*
+ * Link state
+ * ==========
+ *
+ * The backend can advertise its current link (carrier) state to the
+ * frontend using the /local/domain/X/backend/vif/<domid>/<vif>/carrier
+ * node. If this node is not present, then the frontend should assume that
+ * the link is up (for compatibility with backends that do no implement
+ * this feature). If this node is present, then a value of "0" should be
+ * interpreted by the frontend as the link being down (no carrier) and a
+ * value of "1" should be interpreted as the link being up (carrier
+ * present).
+ */
+
/*
* Hash types
* ==========
This patch adds a specification for a 'carrier' node in xenstore to allow a backend to notify a frontend of it's virtual carrier/link state. E.g. a backend that is unable to forward packets from the guest because it is not attached to a bridge may wish to advertise 'no carrier'. While in the area also fix an erroneous backend path description. NOTE: This is purely a documentation patch. No functional change. Signed-off-by: Paul Durrant <pdurrant@amazon.com> --- Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Juergen Gross <jgross@suse.com> v2: - Fix text - Fix path --- xen/include/public/io/netif.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)