mac80211: update PERR frame format

Update the PERR IE frame format according to latest draft (3.03).

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>

3 files changed, 60 insertions, 13 deletions

diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index 2fd3e200a063..1d534c702406 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -210,6 +210,11 @@ struct mesh_rmc {
 #define MESH_PATH_SEL_CATEGORY  32
 #define MESH_PATH_SEL_ACTION    0
 
+/* PERR reason codes */
+#define PEER_RCODE_UNSPECIFIED  11
+#define PERR_RCODE_NO_ROUTE     12
+#define PERR_RCODE_DEST_UNREACH 13
+
 /* Public interfaces */
 /* Various */
 int ieee80211_fill_mesh_addresses(struct ieee80211_hdr *hdr, __le16 *fc,
@@ -275,8 +280,8 @@ void mesh_mpp_table_grow(void);
 u32 mesh_table_hash(u8 *addr, struct ieee80211_sub_if_data *sdata,
                 struct mesh_table *tbl);
 /* Mesh paths */
-int mesh_path_error_tx(u8 *dest, __le32 dest_dsn, u8 *ra,
-                struct ieee80211_sub_if_data *sdata);
+int mesh_path_error_tx(u8 ttl, u8 *dest, __le32 dest_dsn, __le16 dest_rcode,
+                u8 *ra, struct ieee80211_sub_if_data *sdata);
 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
 void mesh_path_flush_pending(struct mesh_path *mpath);
 void mesh_path_tx_pending(struct mesh_path *mpath);
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index 7b9dd87cf9f2..eb4180bff575 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -27,6 +27,10 @@
 #define MP_F_DO 0x1
 /* Reply and forward */
 #define MP_F_RF 0x2
+/* Unknown Sequence Number */
+#define MP_F_USN    0x01
+/* Reason code Present */
+#define MP_F_RCODE  0x02
 
 static void mesh_queue_preq(struct mesh_path *, u8);
 
@@ -37,6 +41,13 @@ static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
         return get_unaligned_le32(preq_elem + offset);
 }
 
+static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
+{
+        if (ae)
+                offset += 6;
+        return get_unaligned_le16(preq_elem + offset);
+}
+
 /* HWMP IE processing macros */
 #define AE_F                    (1<<6)
 #define AE_F_SET(x)             (*x & AE_F)
@@ -63,8 +74,11 @@ static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
 #define PREP_IE_DST_ADDR(x)     (AE_F_SET(x) ? x + 27 : x + 21)
 #define PREP_IE_DST_DSN(x)      u32_field_get(x, 27, AE_F_SET(x));
 
-#define PERR_IE_DST_ADDR(x)     (x + 2)
-#define PERR_IE_DST_DSN(x)      u32_field_get(x, 8, 0);
+#define PERR_IE_TTL(x)          (*(x))
+#define PERR_IE_DST_FLAGS(x)    (*(x + 2))
+#define PERR_IE_DST_ADDR(x)     (x + 3)
+#define PERR_IE_DST_DSN(x)      u32_field_get(x, 9, 0);
+#define PERR_IE_DST_RCODE(x)    u16_field_get(x, 13, 0);
 
 #define MSEC_TO_TU(x) (x*1000/1024)
 #define DSN_GT(x, y) ((long) (y) - (long) (x) < 0)
@@ -181,8 +195,8 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
  * @dst_dsn: dsn of the broken destination
  * @ra: node this frame is addressed to
  */
-int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
-                struct ieee80211_sub_if_data *sdata)
+int mesh_path_error_tx(u8 ttl, u8 *dst, __le32 dst_dsn, __le16 dst_rcode,
+                u8 *ra, struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_local *local = sdata->local;
         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
@@ -207,17 +221,29 @@ int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
         /* BSSID is left zeroed, wildcard value */
         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
-        ie_len = 12;
+        ie_len = 15;
         pos = skb_put(skb, 2 + ie_len);
         *pos++ = WLAN_EID_PERR;
         *pos++ = ie_len;
-        /* mode flags, reserved */
-        *pos++ = 0;
+        /* ttl */
+        *pos++ = MESH_TTL;
         /* number of destinations */
         *pos++ = 1;
+        /*
+         * flags bit, bit 1 is unset if we know the sequence number and
+         * bit 2 is set if we have a reason code
+         */
+        *pos = 0;
+        if (!dst_dsn)
+                *pos |= MP_F_USN;
+        if (dst_rcode)
+                *pos |= MP_F_RCODE;
+        pos++;
         memcpy(pos, dst, ETH_ALEN);
         pos += ETH_ALEN;
         memcpy(pos, &dst_dsn, 4);
+        pos += 4;
+        memcpy(pos, &dst_rcode, 2);
 
         ieee80211_tx_skb(sdata, skb, 1);
         return 0;
@@ -598,13 +624,26 @@ fail:
 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 {
+        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
         struct mesh_path *mpath;
+        u8 ttl;
         u8 *ta, *dst_addr;
+        u8 dst_flags;
         u32 dst_dsn;
+        u16 dst_rcode;
 
         ta = mgmt->sa;
+        ttl = PERR_IE_TTL(perr_elem);
+        if (ttl <= 1) {
+                ifmsh->mshstats.dropped_frames_ttl++;
+                return;
+        }
+        ttl--;
+        dst_flags = PERR_IE_DST_FLAGS(perr_elem);
         dst_addr = PERR_IE_DST_ADDR(perr_elem);
         dst_dsn = PERR_IE_DST_DSN(perr_elem);
+        dst_rcode = PERR_IE_DST_RCODE(perr_elem);
+
         rcu_read_lock();
         mpath = mesh_path_lookup(dst_addr, sdata);
         if (mpath) {
@@ -616,7 +655,8 @@ static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
                         mpath->flags &= ~MESH_PATH_ACTIVE;
                         mpath->dsn = dst_dsn;
                         spin_unlock_bh(&mpath->state_lock);
-                        mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
+                        mesh_path_error_tx(ttl, dst_addr, cpu_to_le32(dst_dsn),
+                                           cpu_to_le16(dst_rcode),
                                            sdata->dev->broadcast, sdata);
                 } else
                         spin_unlock_bh(&mpath->state_lock);
@@ -711,7 +751,7 @@ void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
                                                 last_hop_metric);
         }
         if (elems.perr) {
-                if (elems.perr_len != 12)
+                if (elems.perr_len != 15)
                         /* Right now we support only one destination per PERR */
                         return;
                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 751c4d0e2b36..5d541235ca2f 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -465,8 +465,9 @@ void mesh_plink_broken(struct sta_info *sta)
                         mpath->flags &= ~MESH_PATH_ACTIVE;
                         ++mpath->dsn;
                         spin_unlock_bh(&mpath->state_lock);
-                        mesh_path_error_tx(mpath->dst,
+                        mesh_path_error_tx(MESH_TTL, mpath->dst,
                                         cpu_to_le32(mpath->dsn),
+                                        PERR_RCODE_DEST_UNREACH,
                                         sdata->dev->broadcast, sdata);
                 } else
                 spin_unlock_bh(&mpath->state_lock);
@@ -611,7 +612,8 @@ void mesh_path_discard_frame(struct sk_buff *skb,
                 mpath = mesh_path_lookup(da, sdata);
                 if (mpath)
                         dsn = ++mpath->dsn;
-                mesh_path_error_tx(skb->data, cpu_to_le32(dsn), ra, sdata);
+                mesh_path_error_tx(MESH_TTL, skb->data, cpu_to_le32(dsn),
+                                   PERR_RCODE_NO_ROUTE, ra, sdata);
         }
 
         kfree_skb(skb);