nl80211: PMKSA caching support

This is an interface to set, delete and flush PMKIDs through nl80211.
Main users would be fullmac devices which firmwares are capable of
generating the RSN IEs for the re-association requests, e.g. iwmc3200wifi.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

include/linux/ieee80211.h

@@ -1266,6 +1266,8 @@ enum ieee80211_sa_query_action {
 
 #define WLAN_MAX_KEY_LEN		32
 
+#define WLAN_PMKID_LEN			16
+
 /**
  * ieee80211_get_qos_ctl - get pointer to qos control bytes
  * @hdr: the frame

include/linux/nl80211.h

@@ -349,6 +349,10 @@ enum nl80211_commands {
 	NL80211_CMD_GET_SURVEY,
 	NL80211_CMD_NEW_SURVEY_RESULTS,
 
+	NL80211_CMD_SET_PMKSA,
+	NL80211_CMD_DEL_PMKSA,
+	NL80211_CMD_FLUSH_PMKSA,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -598,6 +602,10 @@ enum nl80211_commands {
  *      the survey response for %NL80211_CMD_GET_SURVEY, nested attribute
  *      containing info as possible, see &enum survey_info.
  *
+ * @NL80211_ATTR_PMKID: PMK material for PMKSA caching.
+ * @NL80211_ATTR_MAX_NUM_PMKIDS: maximum number of PMKIDs a firmware can
+ *	cache, a wiphy attribute.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -732,6 +740,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_SURVEY_INFO,
 
+	NL80211_ATTR_PMKID,
+	NL80211_ATTR_MAX_NUM_PMKIDS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

include/net/cfg80211.h

@@ -871,6 +871,19 @@ struct cfg80211_bitrate_mask {
 	u32 fixed;   /* fixed bitrate, 0 == not fixed */
 	u32 maxrate; /* in kbps, 0 == no limit */
 };
+/**
+ * struct cfg80211_pmksa - PMK Security Association
+ *
+ * This structure is passed to the set/del_pmksa() method for PMKSA
+ * caching.
+ *
+ * @bssid: The AP's BSSID.
+ * @pmkid: The PMK material itself.
+ */
+struct cfg80211_pmksa {
+	u8 *bssid;
+	u8 *pmkid;
+};
 
 /**
  * struct cfg80211_ops - backend description for wireless configuration
@@ -976,6 +989,13 @@ struct cfg80211_bitrate_mask {
  * @dump_survey: get site survey information.
  *
  * @testmode_cmd: run a test mode command
+ *
+ * @set_pmksa: Cache a PMKID for a BSSID. This is mostly useful for fullmac
+ *	devices running firmwares capable of generating the (re) association
+ *	RSN IE. It allows for faster roaming between WPA2 BSSIDs.
+ * @del_pmksa: Delete a cached PMKID.
+ * @flush_pmksa: Flush all cached PMKIDs.
+ *
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy);
@@ -1097,6 +1117,12 @@ struct cfg80211_ops {
 	int	(*dump_survey)(struct wiphy *wiphy, struct net_device *netdev,
 			int idx, struct survey_info *info);
 
+	int	(*set_pmksa)(struct wiphy *wiphy, struct net_device *netdev,
+			     struct cfg80211_pmksa *pmksa);
+	int	(*del_pmksa)(struct wiphy *wiphy, struct net_device *netdev,
+			     struct cfg80211_pmksa *pmksa);
+	int	(*flush_pmksa)(struct wiphy *wiphy, struct net_device *netdev);
+
 	/* some temporary stuff to finish wext */
 	int	(*set_power_mgmt)(struct wiphy *wiphy, struct net_device *dev,
 				  bool enabled, int timeout);
@@ -1195,6 +1221,8 @@ struct wiphy {
 	char fw_version[ETHTOOL_BUSINFO_LEN];
 	u32 hw_version;
 
+	u8 max_num_pmkids;
+
 	/* If multiple wiphys are registered and you're handed e.g.
 	 * a regular netdev with assigned ieee80211_ptr, you won't
 	 * know whether it points to a wiphy your driver has registered

net/wireless/nl80211.c

@@ -139,6 +139,8 @@ static struct nla_policy nl80211_policy[NL80211_ATTR_MAX+1] __read_mostly = {
 	[NL80211_ATTR_WPA_VERSIONS] = { .type = NLA_U32 },
 	[NL80211_ATTR_PID] = { .type = NLA_U32 },
 	[NL80211_ATTR_4ADDR] = { .type = NLA_U8 },
+	[NL80211_ATTR_PMKID] = { .type = NLA_BINARY,
+				 .len = WLAN_PMKID_LEN },
 };
 
 /* policy for the attributes */
@@ -450,6 +452,9 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 		sizeof(u32) * dev->wiphy.n_cipher_suites,
 		dev->wiphy.cipher_suites);
 
+	NLA_PUT_U8(msg, NL80211_ATTR_MAX_NUM_PMKIDS,
+		   dev->wiphy.max_num_pmkids);
+
 	nl_modes = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_IFTYPES);
 	if (!nl_modes)
 		goto nla_put_failure;
@@ -561,6 +566,9 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 	CMD(deauth, DEAUTHENTICATE);
 	CMD(disassoc, DISASSOCIATE);
 	CMD(join_ibss, JOIN_IBSS);
+	CMD(set_pmksa, SET_PMKSA);
+	CMD(del_pmksa, DEL_PMKSA);
+	CMD(flush_pmksa, FLUSH_PMKSA);
 	if (dev->wiphy.flags & WIPHY_FLAG_NETNS_OK) {
 		i++;
 		NLA_PUT_U32(msg, i, NL80211_CMD_SET_WIPHY_NETNS);
@@ -4221,6 +4229,99 @@ static int nl80211_wiphy_netns(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+static int nl80211_setdel_pmksa(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev;
+	int (*rdev_ops)(struct wiphy *wiphy, struct net_device *dev,
+			struct cfg80211_pmksa *pmksa) = NULL;
+	int err;
+	struct net_device *dev;
+	struct cfg80211_pmksa pmksa;
+
+	memset(&pmksa, 0, sizeof(struct cfg80211_pmksa));
+
+	if (!info->attrs[NL80211_ATTR_MAC])
+		return -EINVAL;
+
+	if (!info->attrs[NL80211_ATTR_PMKID])
+		return -EINVAL;
+
+	rtnl_lock();
+
+	err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
+	if (err)
+		goto out_rtnl;
+
+	pmksa.pmkid = nla_data(info->attrs[NL80211_ATTR_PMKID]);
+	pmksa.bssid = nla_data(info->attrs[NL80211_ATTR_MAC]);
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	switch (info->genlhdr->cmd) {
+	case NL80211_CMD_SET_PMKSA:
+		rdev_ops = rdev->ops->set_pmksa;
+		break;
+	case NL80211_CMD_DEL_PMKSA:
+		rdev_ops = rdev->ops->del_pmksa;
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+
+	if (!rdev_ops) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	err = rdev_ops(&rdev->wiphy, dev, &pmksa);
+
+ out:
+	cfg80211_unlock_rdev(rdev);
+	dev_put(dev);
+ out_rtnl:
+	rtnl_unlock();
+
+	return err;
+}
+
+static int nl80211_flush_pmksa(struct sk_buff *skb, struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev;
+	int err;
+	struct net_device *dev;
+
+	rtnl_lock();
+
+	err = get_rdev_dev_by_info_ifindex(info, &rdev, &dev);
+	if (err)
+		goto out_rtnl;
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (!rdev->ops->flush_pmksa) {
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	err = rdev->ops->flush_pmksa(&rdev->wiphy, dev);
+
+ out:
+	cfg80211_unlock_rdev(rdev);
+	dev_put(dev);
+ out_rtnl:
+	rtnl_unlock();
+
+	return err;
+
+}
+
 static struct genl_ops nl80211_ops[] = {
 	{
 		.cmd = NL80211_CMD_GET_WIPHY,
@@ -4465,6 +4566,25 @@ static struct genl_ops nl80211_ops[] = {
 		.policy = nl80211_policy,
 		.dumpit = nl80211_dump_survey,
 	},
+	{
+		.cmd = NL80211_CMD_SET_PMKSA,
+		.doit = nl80211_setdel_pmksa,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = NL80211_CMD_DEL_PMKSA,
+		.doit = nl80211_setdel_pmksa,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = NL80211_CMD_FLUSH_PMKSA,
+		.doit = nl80211_flush_pmksa,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+
 };
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
 	.name = "mlme",