wifi: cfg80211: do some rework towards MLO link APIs

In order to support multi-link operation with multiple links,
start adding some APIs. The notable addition here is to have
the link ID in a new nl80211 attribute, that will be used to
differentiate the links in many nl80211 operations.

So far, this patch adds the netlink NL80211_ATTR_MLO_LINK_ID
attribute (as well as the NL80211_ATTR_MLO_LINKS attribute)
and plugs it through the system in some places, checking the
validity etc. along with other infrastructure needed for it.

For now, I've decided to include only the over-the-air link
ID in the API. I know we discussed that we eventually need to
have to have other ways of identifying a link, but for local
AP mode and auth/assoc commands as well as set_key etc. we'll
use the OTA ID.

Also included in this patch is some refactoring of the data
structures in struct wireless_dev, splitting for the first
time the data into type dependent pieces, to make reasoning
about these things easier.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 98f905f16411..a9a2c9fef295 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -324,6 +324,17 @@
  */
 
 /**
+ * DOC: Multi-Link Operation
+ *
+ * In Multi-Link Operation, a connection between to MLDs utilizes multiple
+ * links. To use this in nl80211, various commands and responses now need
+ * to or will include the new %NL80211_ATTR_MLO_LINKS attribute.
+ * Additionally, various commands that need to operate on a specific link
+ * now need to be given the %NL80211_ATTR_MLO_LINK_ID attribute, e.g. to
+ * use %NL80211_CMD_START_AP or similar functions.
+ */
+
+/**
  * enum nl80211_commands - supported nl80211 commands
  *
  * @NL80211_CMD_UNSPEC: unspecified command to catch errors
@@ -1237,6 +1248,12 @@
  *      to describe the BSSID address of the AP and %NL80211_ATTR_TIMEOUT to
  *      specify the timeout value.
  *
+ * @NL80211_CMD_ADD_LINK: Add a new link to an interface. The
+ *	%NL80211_ATTR_MLO_LINK_ID attribute is used for the new link.
+ * @NL80211_CMD_REMOVE_LINK: Remove a link from an interface. This may come
+ *	without %NL80211_ATTR_MLO_LINK_ID as an easy way to remove all links
+ *	in preparation for e.g. roaming to a regular (non-MLO) AP.
+ *
  * @NL80211_CMD_MAX: highest used command number
  * @__NL80211_CMD_AFTER_LAST: internal use
  */
@@ -1481,6 +1498,9 @@ enum nl80211_commands {
 
 	NL80211_CMD_ASSOC_COMEBACK,
 
+	NL80211_CMD_ADD_LINK,
+	NL80211_CMD_REMOVE_LINK,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -2663,6 +2683,11 @@ enum nl80211_commands {
  *	association request when used with NL80211_CMD_NEW_STATION). Can be set
  *	only if %NL80211_STA_FLAG_WME is set.
  *
+ * @NL80211_ATTR_MLO_LINK_ID: A (u8) link ID for use with MLO, to be used with
+ *	various commands that need a link ID to operate.
+ * @NL80211_ATTR_MLO_LINKS: A nested array of links, each containing some
+ *	per-link information and a link ID.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3177,6 +3202,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_DISABLE_EHT,
 
+	NL80211_ATTR_MLO_LINKS,
+	NL80211_ATTR_MLO_LINK_ID,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,