nl80211/cfg80211: add radar detection command/event

Add new NL80211_CMD_RADAR_DETECT, which starts the Channel
Availability Check (CAC). This command will also notify the
usermode about events (CAC finished, CAC aborted, radar
detected, NOP finished).
Once radar detection has started it should continuously
monitor for radars as long as the channel is active.

This patch enables DFS for AP mode in nl80211/cfg80211.

Based on original patch by Victor Goldenshtein <victorg@ti.com>

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
[remove WIPHY_FLAG_HAS_RADAR_DETECT again -- my mistake]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 130 insertions, 5 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d29a461b4981..c1e18ccf4049 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -552,9 +552,16 @@ static int nl80211_msg_put_channel(struct sk_buff *msg,
         if ((chan->flags & IEEE80211_CHAN_NO_IBSS) &&
             nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_IBSS))
                 goto nla_put_failure;
-        if ((chan->flags & IEEE80211_CHAN_RADAR) &&
-            nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
-                goto nla_put_failure;
+        if (chan->flags & IEEE80211_CHAN_RADAR) {
+                u32 time = elapsed_jiffies_msecs(chan->dfs_state_entered);
+                if (nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
+                        goto nla_put_failure;
+                if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_STATE,
+                                chan->dfs_state))
+                        goto nla_put_failure;
+                if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_TIME, time))
+                        goto nla_put_failure;
+        }
 
         if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
                         DBM_TO_MBM(chan->max_power)))
@@ -2775,6 +2782,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
         struct wireless_dev *wdev = dev->ieee80211_ptr;
         struct cfg80211_ap_settings params;
         int err;
+        u8 radar_detect_width = 0;
 
         if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
             dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
@@ -2893,9 +2901,19 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
         if (!cfg80211_reg_can_beacon(&rdev->wiphy, &params.chandef))
                 return -EINVAL;
 
+        err = cfg80211_chandef_dfs_required(wdev->wiphy, &params.chandef);
+        if (err < 0)
+                return err;
+        if (err) {
+                radar_detect_width = BIT(params.chandef.width);
+                params.radar_required = true;
+        }
+
         mutex_lock(&rdev->devlist_mtx);
-        err = cfg80211_can_use_chan(rdev, wdev, params.chandef.chan,
-                                    CHAN_MODE_SHARED);
+        err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+                                           params.chandef.chan,
+                                           CHAN_MODE_SHARED,
+                                           radar_detect_width);
         mutex_unlock(&rdev->devlist_mtx);
 
         if (err)
@@ -5055,6 +5073,54 @@ static int nl80211_stop_sched_scan(struct sk_buff *skb,
         return err;
 }
 
+static int nl80211_start_radar_detection(struct sk_buff *skb,
+                                         struct genl_info *info)
+{
+        struct cfg80211_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct wireless_dev *wdev = dev->ieee80211_ptr;
+        struct cfg80211_chan_def chandef;
+        int err;
+
+        err = nl80211_parse_chandef(rdev, info, &chandef);
+        if (err)
+                return err;
+
+        if (wdev->cac_started)
+                return -EBUSY;
+
+        err = cfg80211_chandef_dfs_required(wdev->wiphy, &chandef);
+        if (err < 0)
+                return err;
+
+        if (err == 0)
+                return -EINVAL;
+
+        if (chandef.chan->dfs_state != NL80211_DFS_USABLE)
+                return -EINVAL;
+
+        if (!rdev->ops->start_radar_detection)
+                return -EOPNOTSUPP;
+
+        mutex_lock(&rdev->devlist_mtx);
+        err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+                                           chandef.chan, CHAN_MODE_SHARED,
+                                           BIT(chandef.width));
+        if (err)
+                goto err_locked;
+
+        err = rdev->ops->start_radar_detection(&rdev->wiphy, dev, &chandef);
+        if (!err) {
+                wdev->channel = chandef.chan;
+                wdev->cac_started = true;
+                wdev->cac_start_time = jiffies;
+        }
+err_locked:
+        mutex_unlock(&rdev->devlist_mtx);
+
+        return err;
+}
+
 static int nl80211_send_bss(struct sk_buff *msg, struct netlink_callback *cb,
                             u32 seq, int flags,
                             struct cfg80211_registered_device *rdev,
@@ -8305,6 +8371,14 @@ static struct genl_ops nl80211_ops[] = {
                 .internal_flags = NL80211_FLAG_NEED_NETDEV |
                                   NL80211_FLAG_NEED_RTNL,
         },
+        {
+                .cmd = NL80211_CMD_RADAR_DETECT,
+                .doit = nl80211_start_radar_detection,
+                .policy = nl80211_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+                                  NL80211_FLAG_NEED_RTNL,
+        },
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
@@ -9502,6 +9576,57 @@ nl80211_send_cqm_txe_notify(struct cfg80211_registered_device *rdev,
 }
 
 void
+nl80211_radar_notify(struct cfg80211_registered_device *rdev,
+                     struct cfg80211_chan_def *chandef,
+                     enum nl80211_radar_event event,
+                     struct net_device *netdev, gfp_t gfp)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+        if (!msg)
+                return;
+
+        hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_RADAR_DETECT);
+        if (!hdr) {
+                nlmsg_free(msg);
+                return;
+        }
+
+        if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx))
+                goto nla_put_failure;
+
+        /* NOP and radar events don't need a netdev parameter */
+        if (netdev) {
+                struct wireless_dev *wdev = netdev->ieee80211_ptr;
+
+                if (nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex) ||
+                    nla_put_u64(msg, NL80211_ATTR_WDEV, wdev_id(wdev)))
+                        goto nla_put_failure;
+        }
+
+        if (nla_put_u32(msg, NL80211_ATTR_RADAR_EVENT, event))
+                goto nla_put_failure;
+
+        if (nl80211_send_chandef(msg, chandef))
+                goto nla_put_failure;
+
+        if (genlmsg_end(msg, hdr) < 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);
+}
+
+void
 nl80211_send_cqm_pktloss_notify(struct cfg80211_registered_device *rdev,
                                 struct net_device *netdev, const u8 *peer,
                                 u32 num_packets, gfp_t gfp)