mac80211: implement the proactive PREP generation

Generate the proactive PREP element in Proactive PREQ mode as
defined in Sec. 13.10.10.3 (Case D) of IEEE Std. 802.11-2012.

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 33 insertions, 5 deletions

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index a6b08f5c461..35e3acbe226 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -516,10 +516,11 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
         struct mesh_path *mpath = NULL;
         u8 *target_addr, *orig_addr;
         const u8 *da;
-        u8 target_flags, ttl;
-        u32 orig_sn, target_sn, lifetime;
+        u8 target_flags, ttl, flags;
+        u32 orig_sn, target_sn, lifetime, orig_metric;
         bool reply = false;
         bool forward = true;
+        bool root_is_gate;
 
         /* Update target SN, if present */
         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
@@ -527,6 +528,10 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
         target_sn = PREQ_IE_TARGET_SN(preq_elem);
         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
         target_flags = PREQ_IE_TARGET_F(preq_elem);
+        orig_metric = metric;
+        /* Proactive PREQ gate announcements */
+        flags = PREQ_IE_FLAGS(preq_elem);
+        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 
         mhwmp_dbg("received PREQ from %pM", orig_addr);
 
@@ -541,6 +546,22 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
                         target_sn = ++ifmsh->sn;
                         ifmsh->last_sn_update = jiffies;
                 }
+        } else if (is_broadcast_ether_addr(target_addr) &&
+                   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
+                rcu_read_lock();
+                mpath = mesh_path_lookup(orig_addr, sdata);
+                if (mpath) {
+                        if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
+                                reply = true;
+                                target_addr = sdata->vif.addr;
+                                target_sn = ++ifmsh->sn;
+                                metric = 0;
+                                ifmsh->last_sn_update = jiffies;
+                        }
+                        if (root_is_gate)
+                                mesh_path_add_gate(mpath);
+                }
+                rcu_read_unlock();
         } else {
                 rcu_read_lock();
                 mpath = mesh_path_lookup(target_addr, sdata);
@@ -573,13 +594,14 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
                                 0, sdata);
-                } else
+                } else {
                         ifmsh->mshstats.dropped_frames_ttl++;
+                }
         }
 
         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
                 u32 preq_id;
-                u8 hopcount, flags;
+                u8 hopcount;
 
                 ttl = PREQ_IE_TTL(preq_elem);
                 lifetime = PREQ_IE_LIFETIME(preq_elem);
@@ -589,11 +611,17 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
                 }
                 mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
                 --ttl;
-                flags = PREQ_IE_FLAGS(preq_elem);
                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
                 da = (mpath && mpath->is_root) ?
                         mpath->rann_snd_addr : broadcast_addr;
+
+                if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
+                        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
+                        target_sn = PREQ_IE_TARGET_SN(preq_elem);
+                        metric = orig_metric;
+                }
+
                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
                                 cpu_to_le32(orig_sn), target_flags, target_addr,
                                 cpu_to_le32(target_sn), da,