cfg80211: Add TDLS event to allow drivers to request operations

The NL80211_CMD_TDLS_OPER command was previously used only for userspace
request for the kernel code to perform TDLS operations. However, there
are also cases where the driver may need to request operations from
userspace, e.g., when using security on the AP path. Add a new cfg80211
function for generating a TDLS operation event for drivers to request a
new link to be set up (NL80211_TDLS_SETUP) or an existing link to be
torn down (NL80211_TDLS_TEARDOWN). Drivers can optionally use these
events, e.g., based on noticing data traffic being sent to a peer
station that is seen with good signal strength.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -9027,6 +9027,53 @@ void cfg80211_report_obss_beacon(struct wiphy *wiphy,
 }
 EXPORT_SYMBOL(cfg80211_report_obss_beacon);
 
+void cfg80211_tdls_oper_request(struct net_device *dev, const u8 *peer,
+				enum nl80211_tdls_operation oper,
+				u16 reason_code, gfp_t gfp)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
+	struct sk_buff *msg;
+	void *hdr;
+	int err;
+
+	trace_cfg80211_tdls_oper_request(wdev->wiphy, dev, peer, oper,
+					 reason_code);
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_TDLS_OPER);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
+	    nla_put_u32(msg, NL80211_ATTR_IFINDEX, dev->ifindex) ||
+	    nla_put_u8(msg, NL80211_ATTR_TDLS_OPERATION, oper) ||
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, peer) ||
+	    (reason_code > 0 &&
+	     nla_put_u16(msg, NL80211_ATTR_REASON_CODE, reason_code)))
+		goto nla_put_failure;
+
+	err = genlmsg_end(msg, hdr);
+	if (err < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+				nl80211_mlme_mcgrp.id, gfp);
+	return;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	nlmsg_free(msg);
+}
+EXPORT_SYMBOL(cfg80211_tdls_oper_request);
+
 static int nl80211_netlink_notify(struct notifier_block * nb,
 				  unsigned long state,
 				  void *_notify)