cfg80211: Indicate MLO connection info in connect and roam callbacks

The MLO links used for connection with an MLD AP are decided by the
driver in case of SME offloaded to driver.

Add support for the drivers to indicate the information of links used
for MLO connection in connect and roam callbacks, update the connected
links information in wdev from connect/roam result sent by driver.
Also, send the connected links information to userspace.

Add a netlink flag attribute to indicate that userspace supports
handling of MLO connection. Drivers must not do MLO connection when this
flag is not set. This is to maintain backwards compatibility with older
supplicant versions which doesn't have support for MLO connection.

Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 114 insertions, 6 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index aca799b9971e..6a45801c783c 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -797,6 +797,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_MLO_LINK_ID] =
 		NLA_POLICY_RANGE(NLA_U8, 0, IEEE80211_MLD_MAX_NUM_LINKS),
 	[NL80211_ATTR_MLD_ADDR] = NLA_POLICY_EXACT_LEN(ETH_ALEN),
+	[NL80211_ATTR_MLO_SUPPORT] = { .type = NLA_FLAG },
 };
 
 /* policy for the key attributes */
@@ -11529,6 +11530,9 @@ static int nl80211_connect(struct sk_buff *skb, struct genl_info *info)
 		connect.flags |= CONNECT_REQ_EXTERNAL_AUTH_SUPPORT;
 	}
 
+	if (nla_get_flag(info->attrs[NL80211_ATTR_MLO_SUPPORT]))
+		connect.flags |= CONNECT_REQ_MLO_SUPPORT;
+
 	wdev_lock(dev->ieee80211_ptr);
 
 	err = cfg80211_connect(rdev, dev, &connect, connkeys,
@@ -17304,10 +17308,29 @@ void nl80211_send_connect_result(struct cfg80211_registered_device *rdev,
 {
 	struct sk_buff *msg;
 	void *hdr;
+	unsigned int link;
+	size_t link_info_size = 0;
+	const u8 *connected_addr = cr->valid_links ?
+				   cr->ap_mld_addr : cr->links[0].bssid;
+
+	if (cr->valid_links) {
+		for_each_valid_link(cr, link) {
+			/* Nested attribute header */
+			link_info_size += NLA_HDRLEN;
+			/* Link ID */
+			link_info_size += nla_total_size(sizeof(u8));
+			link_info_size += cr->links[link].addr ?
+					  nla_total_size(ETH_ALEN) : 0;
+			link_info_size += (cr->links[link].bssid ||
+					   cr->links[link].bss) ?
+					  nla_total_size(ETH_ALEN) : 0;
+		}
+	}
 
 	msg = nlmsg_new(100 + cr->req_ie_len + cr->resp_ie_len +
 			cr->fils.kek_len + cr->fils.pmk_len +
-			(cr->fils.pmkid ? WLAN_PMKID_LEN : 0), gfp);
+			(cr->fils.pmkid ? WLAN_PMKID_LEN : 0) + link_info_size,
+			gfp);
 	if (!msg)
 		return;
 
@@ -17319,8 +17342,8 @@ void nl80211_send_connect_result(struct cfg80211_registered_device *rdev,
 
 	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
 	    nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex) ||
-	    (cr->bssid &&
-	     nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, cr->bssid)) ||
+	    (connected_addr &&
+	     nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, connected_addr)) ||
 	    nla_put_u16(msg, NL80211_ATTR_STATUS_CODE,
 			cr->status < 0 ? WLAN_STATUS_UNSPECIFIED_FAILURE :
 			cr->status) ||
@@ -17346,6 +17369,38 @@ void nl80211_send_connect_result(struct cfg80211_registered_device *rdev,
 	       nla_put(msg, NL80211_ATTR_PMKID, WLAN_PMKID_LEN, cr->fils.pmkid)))))
 		goto nla_put_failure;
 
+	if (cr->valid_links) {
+		int i = 1;
+		struct nlattr *nested;
+
+		nested = nla_nest_start(msg, NL80211_ATTR_MLO_LINKS);
+		if (!nested)
+			goto nla_put_failure;
+
+		for_each_valid_link(cr, link) {
+			struct nlattr *nested_mlo_links;
+			const u8 *bssid = cr->links[link].bss ?
+					  cr->links[link].bss->bssid :
+					  cr->links[link].bssid;
+
+			nested_mlo_links = nla_nest_start(msg, i);
+			if (!nested_mlo_links)
+				goto nla_put_failure;
+
+			if (nla_put_u8(msg, NL80211_ATTR_MLO_LINK_ID, link) ||
+			    (bssid &&
+			     nla_put(msg, NL80211_ATTR_BSSID, ETH_ALEN, bssid)) ||
+			    (cr->links[link].addr &&
+			     nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN,
+				     cr->links[link].addr)))
+				goto nla_put_failure;
+
+			nla_nest_end(msg, nested_mlo_links);
+			i++;
+		}
+		nla_nest_end(msg, nested);
+	}
+
 	genlmsg_end(msg, hdr);
 
 	genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,
@@ -17362,11 +17417,32 @@ void nl80211_send_roamed(struct cfg80211_registered_device *rdev,
 {
 	struct sk_buff *msg;
 	void *hdr;
-	const u8 *bssid = info->bss ? info->bss->bssid : info->bssid;
+	size_t link_info_size = 0;
+	unsigned int link;
+	const u8 *connected_addr = info->ap_mld_addr ?
+				   info->ap_mld_addr :
+				   (info->links[0].bss ?
+				    info->links[0].bss->bssid :
+				    info->links[0].bssid);
+
+	if (info->valid_links) {
+		for_each_valid_link(info, link) {
+			/* Nested attribute header */
+			link_info_size += NLA_HDRLEN;
+			/* Link ID */
+			link_info_size += nla_total_size(sizeof(u8));
+			link_info_size += info->links[link].addr ?
+					  nla_total_size(ETH_ALEN) : 0;
+			link_info_size += (info->links[link].bssid ||
+					   info->links[link].bss) ?
+					  nla_total_size(ETH_ALEN) : 0;
+		}
+	}
 
 	msg = nlmsg_new(100 + info->req_ie_len + info->resp_ie_len +
 			info->fils.kek_len + info->fils.pmk_len +
-			(info->fils.pmkid ? WLAN_PMKID_LEN : 0), gfp);
+			(info->fils.pmkid ? WLAN_PMKID_LEN : 0) +
+			link_info_size, gfp);
 	if (!msg)
 		return;
 
@@ -17378,7 +17454,7 @@ void nl80211_send_roamed(struct cfg80211_registered_device *rdev,
 
 	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx) ||
 	    nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex) ||
-	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, bssid) ||
+	    nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN, connected_addr) ||
 	    (info->req_ie &&
 	     nla_put(msg, NL80211_ATTR_REQ_IE, info->req_ie_len,
 		     info->req_ie)) ||
@@ -17397,6 +17473,38 @@ void nl80211_send_roamed(struct cfg80211_registered_device *rdev,
 	     nla_put(msg, NL80211_ATTR_PMKID, WLAN_PMKID_LEN, info->fils.pmkid)))
 		goto nla_put_failure;
 
+	if (info->valid_links) {
+		int i = 1;
+		struct nlattr *nested;
+
+		nested = nla_nest_start(msg, NL80211_ATTR_MLO_LINKS);
+		if (!nested)
+			goto nla_put_failure;
+
+		for_each_valid_link(info, link) {
+			struct nlattr *nested_mlo_links;
+			const u8 *bssid = info->links[link].bss ?
+					  info->links[link].bss->bssid :
+					  info->links[link].bssid;
+
+			nested_mlo_links = nla_nest_start(msg, i);
+			if (!nested_mlo_links)
+				goto nla_put_failure;
+
+			if (nla_put_u8(msg, NL80211_ATTR_MLO_LINK_ID, link) ||
+			    (bssid &&
+			     nla_put(msg, NL80211_ATTR_BSSID, ETH_ALEN, bssid)) ||
+			    (info->links[link].addr &&
+			     nla_put(msg, NL80211_ATTR_MAC, ETH_ALEN,
+				     info->links[link].addr)))
+				goto nla_put_failure;
+
+			nla_nest_end(msg, nested_mlo_links);
+			i++;
+		}
+		nla_nest_end(msg, nested);
+	}
+
 	genlmsg_end(msg, hdr);
 
 	genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,