cfg80211: support an active monitor interface flag

An active monitor interface is one that is used for communication (via
injection). It is expected to ACK incoming unicast packets. This is
useful for running various 802.11 testing utilities that associate to an
AP via injection and manage the state in user space.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index b3b076a46d5074ce9d4868968d2be1455b339c6f..13b247d265449e862c0fdb8de6eba2900c5a430b 100644 (file)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -961,6 +961,7 @@ struct station_info {
  * @MONITOR_FLAG_CONTROL: pass control frames
  * @MONITOR_FLAG_OTHER_BSS: disable BSSID filtering
  * @MONITOR_FLAG_COOK_FRAMES: report frames after processing
+ * @MONITOR_FLAG_ACTIVE: active monitor, ACKs frames on its MAC address
  */
 enum monitor_flags {
        MONITOR_FLAG_FCSFAIL            = 1<<NL80211_MNTR_FLAG_FCSFAIL,
@@ -968,6 +969,7 @@ enum monitor_flags {
        MONITOR_FLAG_CONTROL            = 1<<NL80211_MNTR_FLAG_CONTROL,
        MONITOR_FLAG_OTHER_BSS          = 1<<NL80211_MNTR_FLAG_OTHER_BSS,
        MONITOR_FLAG_COOK_FRAMES        = 1<<NL80211_MNTR_FLAG_COOK_FRAMES,
+       MONITOR_FLAG_ACTIVE             = 1<<NL80211_MNTR_FLAG_ACTIVE,
 };
 
 /**

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 32b060ea526649ec76d26dd875b7ff7f1a476de5..5920715278c268c10707109a57cc358fbd65575a 100644 (file)
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2428,6 +2428,8 @@ enum nl80211_survey_info {
  * @NL80211_MNTR_FLAG_OTHER_BSS: disable BSSID filtering
  * @NL80211_MNTR_FLAG_COOK_FRAMES: report frames after processing.
  *     overrides all other flags.
+ * @NL80211_MNTR_FLAG_ACTIVE: use the configured MAC address
+ *     and ACK incoming unicast packets.
  *
  * @__NL80211_MNTR_FLAG_AFTER_LAST: internal use
  * @NL80211_MNTR_FLAG_MAX: highest possible monitor flag
@@ -2439,6 +2441,7 @@ enum nl80211_mntr_flags {
        NL80211_MNTR_FLAG_CONTROL,
        NL80211_MNTR_FLAG_OTHER_BSS,
        NL80211_MNTR_FLAG_COOK_FRAMES,
+       NL80211_MNTR_FLAG_ACTIVE,
 
        /* keep last */
        __NL80211_MNTR_FLAG_AFTER_LAST,
@@ -3595,6 +3598,7 @@ enum nl80211_feature_flags {
        NL80211_FEATURE_ADVERTISE_CHAN_LIMITS           = 1 << 14,
        NL80211_FEATURE_FULL_AP_CLIENT_STATE            = 1 << 15,
        NL80211_FEATURE_USERSPACE_MPM                   = 1 << 16,
+       NL80211_FEATURE_ACTIVE_MONITOR                  = 1 << 17,
 };
 
 /**

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index fb6abcb359a148677f61a1165289814e805cdda1..31d265f36d2cc27125316b925c761d619ab9107f 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2227,6 +2227,7 @@ static const struct nla_policy mntr_flags_policy[NL80211_MNTR_FLAG_MAX + 1] = {
        [NL80211_MNTR_FLAG_CONTROL] = { .type = NLA_FLAG },
        [NL80211_MNTR_FLAG_OTHER_BSS] = { .type = NLA_FLAG },
        [NL80211_MNTR_FLAG_COOK_FRAMES] = { .type = NLA_FLAG },
+       [NL80211_MNTR_FLAG_ACTIVE] = { .type = NLA_FLAG },
 };
 
 static int parse_monitor_flags(struct nlattr *nla, u32 *mntrflags)
@@ -2338,6 +2339,10 @@ static int nl80211_set_interface(struct sk_buff *skb, struct genl_info *info)
                change = true;
        }
 
+       if (flags && (*flags & NL80211_MNTR_FLAG_ACTIVE) &&
+           !(rdev->wiphy.features & NL80211_FEATURE_ACTIVE_MONITOR))
+               return -EOPNOTSUPP;
+
        if (change)
                err = cfg80211_change_iface(rdev, dev, ntype, flags, &params);
        else
@@ -2395,6 +2400,11 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
        err = parse_monitor_flags(type == NL80211_IFTYPE_MONITOR ?
                                  info->attrs[NL80211_ATTR_MNTR_FLAGS] : NULL,
                                  &flags);
+
+       if (!err && (flags & NL80211_MNTR_FLAG_ACTIVE) &&
+           !(rdev->wiphy.features & NL80211_FEATURE_ACTIVE_MONITOR))
+               return -EOPNOTSUPP;
+
        wdev = rdev_add_virtual_intf(rdev,
                                nla_data(info->attrs[NL80211_ATTR_IFNAME]),
                                type, err ? NULL : &flags, &params);