mac80211: implement RANN processing and forwarding

Process the RANN (Root Annoucement) Frame and try to find the HWMP
root station by sending a PREQ.

Signed-off-by: Rui Paulo <rpaulo@gmail.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Reviewed-by: Andrey Yurovsky <andrey@cozybit.com>
Tested-by: Brian Cavagnolo <brian@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 50c684d..49b1abd 100644 (file)
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -554,6 +554,20 @@ struct ieee80211_tim_ie {
        u8 virtual_map[1];
 } __attribute__ ((packed));
 
+/**
+ * struct ieee80211_rann_ie
+ *
+ * This structure refers to "Root Announcement information element"
+ */
+struct ieee80211_rann_ie {
+       u8 rann_flags;
+       u8 rann_hopcount;
+       u8 rann_ttl;
+       u8 rann_addr[6];
+       u32 rann_seq;
+       u32 rann_metric;
+} __attribute__ ((packed));
+
 #define WLAN_SA_QUERY_TR_ID_LEN 2
 
 struct ieee80211_mgmt {
@@ -1070,6 +1084,7 @@ enum ieee80211_eid {
        WLAN_EID_PREQ = 68,
        WLAN_EID_PREP = 69,
        WLAN_EID_PERR = 70,
+       WLAN_EID_RANN = 49,     /* compatible with FreeBSD */
        /* 802.11h */
        WLAN_EID_PWR_CONSTRAINT = 32,
        WLAN_EID_PWR_CAPABILITY = 33,

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 19b0c12..2a7d3d4 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -804,6 +804,7 @@ struct ieee802_11_elems {
        u8 *preq;
        u8 *prep;
        u8 *perr;
+       struct ieee80211_rann_ie *rann;
        u8 *ch_switch_elem;
        u8 *country_elem;
        u8 *pwr_constr_elem;

diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index db1a330..7b9dd87 100644 (file)
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -28,6 +28,8 @@
 /* Reply and forward */
 #define MP_F_RF        0x2
 
+static void mesh_queue_preq(struct mesh_path *, u8);
+
 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
 {
        if (ae)
@@ -81,7 +83,8 @@ static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
 enum mpath_frame_type {
        MPATH_PREQ = 0,
        MPATH_PREP,
-       MPATH_PERR
+       MPATH_PERR,
+       MPATH_RANN
 };
 
 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
@@ -109,7 +112,8 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 
        memcpy(mgmt->da, da, ETH_ALEN);
        memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
-       /* BSSID is left zeroed, wildcard value */
+       /* BSSID == SA */
+       memcpy(mgmt->bssid, sdata->dev->dev_addr, ETH_ALEN);
        mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
        mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
 
@@ -126,6 +130,12 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
                pos = skb_put(skb, 2 + ie_len);
                *pos++ = WLAN_EID_PREP;
                break;
+       case MPATH_RANN:
+               mhwmp_dbg("sending RANN from %pM\n", orig_addr);
+               ie_len = sizeof(struct ieee80211_rann_ie);
+               pos = skb_put(skb, 2 + ie_len);
+               *pos++ = WLAN_EID_RANN;
+               break;
        default:
                kfree_skb(skb);
                return -ENOTSUPP;
@@ -143,8 +153,10 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
        pos += ETH_ALEN;
        memcpy(pos, &orig_dsn, 4);
        pos += 4;
-       memcpy(pos, &lifetime, 4);
-       pos += 4;
+       if (action != MPATH_RANN) {
+               memcpy(pos, &lifetime, 4);
+               pos += 4;
+       }
        memcpy(pos, &metric, 4);
        pos += 4;
        if (action == MPATH_PREQ) {
@@ -152,9 +164,11 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
                *pos++ = 1;
                *pos++ = dst_flags;
        }
-       memcpy(pos, dst, ETH_ALEN);
-       pos += ETH_ALEN;
-       memcpy(pos, &dst_dsn, 4);
+       if (action != MPATH_RANN) {
+               memcpy(pos, dst, ETH_ALEN);
+               pos += ETH_ALEN;
+               memcpy(pos, &dst_dsn, 4);
+       }
 
        ieee80211_tx_skb(sdata, skb, 1);
        return 0;
@@ -610,6 +624,54 @@ static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
        rcu_read_unlock();
 }
 
+static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
+                               struct ieee80211_mgmt *mgmt,
+                               struct ieee80211_rann_ie *rann)
+{
+       struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+       struct mesh_path *mpath;
+       u8 *ta;
+       u8 ttl, flags, hopcount;
+       u8 *orig_addr;
+       u32 orig_dsn, metric;
+
+       ta = mgmt->sa;
+       ttl = rann->rann_ttl;
+       if (ttl <= 1) {
+               ifmsh->mshstats.dropped_frames_ttl++;
+               return;
+       }
+       ttl--;
+       flags = rann->rann_flags;
+       orig_addr = rann->rann_addr;
+       orig_dsn = rann->rann_seq;
+       hopcount = rann->rann_hopcount;
+       metric = rann->rann_metric;
+       mhwmp_dbg("received RANN from %pM\n", orig_addr);
+
+       rcu_read_lock();
+       mpath = mesh_path_lookup(orig_addr, sdata);
+       if (!mpath) {
+               mesh_path_add(orig_addr, sdata);
+               mpath = mesh_path_lookup(orig_addr, sdata);
+               if (!mpath) {
+                       rcu_read_unlock();
+                       sdata->u.mesh.mshstats.dropped_frames_no_route++;
+                       return;
+               }
+               mesh_queue_preq(mpath,
+                               PREQ_Q_F_START | PREQ_Q_F_REFRESH);
+       }
+       if (mpath->dsn < orig_dsn) {
+               mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
+                                      cpu_to_le32(orig_dsn),
+                                      0, NULL, 0, sdata->dev->broadcast,
+                                      hopcount, ttl, 0, cpu_to_le32(metric),
+                                      0, sdata);
+               mpath->dsn = orig_dsn;
+       }
+       rcu_read_unlock();
+}
 
 
 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
@@ -654,7 +716,8 @@ void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
                        return;
                hwmp_perr_frame_process(sdata, mgmt, elems.perr);
        }
-
+       if (elems.rann)
+               hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 }
 
 /**

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index aedbaaa..da86e15 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -685,6 +685,10 @@ u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
                        elems->perr = pos;
                        elems->perr_len = elen;
                        break;
+               case WLAN_EID_RANN:
+                       if (elen >= sizeof(struct ieee80211_rann_ie))
+                               elems->rann = (void *)pos;
+                       break;
                case WLAN_EID_CHANNEL_SWITCH:
                        elems->ch_switch_elem = pos;
                        elems->ch_switch_elem_len = elen;