mac80211: Use 3-address format for mesh broadcast frames.

The 11s task group recently changed the frame mesh multicast/broadcast frame
format to use 3-address.  This was done to avoid interactions with widely
deployed lazy-WDS access points.

This patch changes the format of group addressed frames, both mesh-originated
and proxied, to use the data format defined in draft D2.08 and forward.  The
address fields used for group addressed frames is:

In 802.11 header
 ToDS:0  FromDS:1
 addr1: DA  (broadcast/multicast address)
 addr2: TA
 addr3: Mesh SA

In address extension header:
 addr4: SA  (only present if frame was proxied)

Note that this change breaks backward compatibility with earlier mesh stack
versions.

Signed-off-by: Andrey Yurovsky <andrey@cozybit.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 34 insertions, 30 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 32442980cc24..ee8aa76f071a 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1414,9 +1414,7 @@ static void ieee80211_xmit(struct ieee80211_sub_if_data *sdata,
 
         if (ieee80211_vif_is_mesh(&sdata->vif) &&
             ieee80211_is_data(hdr->frame_control)) {
-                if (is_multicast_ether_addr(hdr->addr3))
-                        memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
-                else
+                if (!is_multicast_ether_addr(hdr->addr1))
                         if (mesh_nexthop_lookup(skb, sdata)) {
                                 dev_put(sdata->dev);
                                 return;
@@ -1619,52 +1617,58 @@ int ieee80211_subif_start_xmit(struct sk_buff *skb,
                 break;
 #ifdef CONFIG_MAC80211_MESH
         case NL80211_IFTYPE_MESH_POINT:
-                fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
                 if (!sdata->u.mesh.mshcfg.dot11MeshTTL) {
                         /* Do not send frames with mesh_ttl == 0 */
                         sdata->u.mesh.mshstats.dropped_frames_ttl++;
                         ret = NETDEV_TX_OK;
                         goto fail;
                 }
-                memset(&mesh_hdr, 0, sizeof(mesh_hdr));
 
                 if (compare_ether_addr(dev->dev_addr,
                                           skb->data + ETH_ALEN) == 0) {
-                        /* RA TA DA SA */
-                        memset(hdr.addr1, 0, ETH_ALEN);
-                        memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
-                        memcpy(hdr.addr3, skb->data, ETH_ALEN);
-                        memcpy(hdr.addr4, skb->data + ETH_ALEN, ETH_ALEN);
-                        meshhdrlen = ieee80211_new_mesh_header(&mesh_hdr, sdata);
+                        hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
+                                        skb->data, skb->data + ETH_ALEN);
+                        meshhdrlen = ieee80211_new_mesh_header(&mesh_hdr,
+                                        sdata, NULL, NULL, NULL);
                 } else {
                         /* packet from other interface */
                         struct mesh_path *mppath;
+                        int is_mesh_mcast = 1;
+                        char *mesh_da;
 
-                        memset(hdr.addr1, 0, ETH_ALEN);
-                        memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);
-                        memcpy(hdr.addr4, dev->dev_addr, ETH_ALEN);
-
+                        rcu_read_lock();
                         if (is_multicast_ether_addr(skb->data))
-                                memcpy(hdr.addr3, skb->data, ETH_ALEN);
+                                /* DA TA mSA AE:SA */
+                                mesh_da = skb->data;
                         else {
-                                rcu_read_lock();
                                 mppath = mpp_path_lookup(skb->data, sdata);
-                                if (mppath)
-                                        memcpy(hdr.addr3, mppath->mpp, ETH_ALEN);
-                                else
-                                        memset(hdr.addr3, 0xff, ETH_ALEN);
-                                rcu_read_unlock();
+                                if (mppath) {
+                                        /* RA TA mDA mSA AE:DA SA */
+                                        mesh_da = mppath->mpp;
+                                        is_mesh_mcast = 0;
+                                } else
+                                        /* DA TA mSA AE:SA */
+                                        mesh_da = dev->broadcast;
                         }
+                        hdrlen = ieee80211_fill_mesh_addresses(&hdr, &fc,
+                                        mesh_da, dev->dev_addr);
+                        rcu_read_unlock();
+                        if (is_mesh_mcast)
+                                meshhdrlen =
+                                        ieee80211_new_mesh_header(&mesh_hdr,
+                                                        sdata,
+                                                        skb->data + ETH_ALEN,
+                                                        NULL,
+                                                        NULL);
+                        else
+                                meshhdrlen =
+                                        ieee80211_new_mesh_header(&mesh_hdr,
+                                                        sdata,
+                                                        NULL,
+                                                        skb->data,
+                                                        skb->data + ETH_ALEN);
 
-                        mesh_hdr.flags |= MESH_FLAGS_AE_A5_A6;
-                        mesh_hdr.ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
-                        put_unaligned(cpu_to_le32(sdata->u.mesh.mesh_seqnum), &mesh_hdr.seqnum);
-                        memcpy(mesh_hdr.eaddr1, skb->data, ETH_ALEN);
-                        memcpy(mesh_hdr.eaddr2, skb->data + ETH_ALEN, ETH_ALEN);
-                        sdata->u.mesh.mesh_seqnum++;
-                        meshhdrlen = 18;
                 }
-                hdrlen = 30;
                 break;
 #endif
         case NL80211_IFTYPE_STATION: