mac80211: fix use of skb->cb for mesh forwarding

Now we deal with mesh forwarding before the 802.11->802.3 conversion, thus
eliminating a few unnecessary steps. The next hop lookup is called from
ieee80211_master_start_xmit() instead of subif_start_xmit(). Until the next hop
is found, RA in the frame will be all zeroes for frames originating from the
device. For forwarded frames, RA will contain the TA of the received frame,
which will be necessary to send a path error if a next hop is not found.

Signed-off-by: Luis Carlos Cobo <luisca@cozybit.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 67 insertions, 49 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 6d9ae67c27ca..6db854505193 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1109,20 +1109,9 @@ ieee80211_data_to_8023(struct ieee80211_rx_data *rx)
 
         hdrlen = ieee80211_get_hdrlen(fc);
 
-        if (ieee80211_vif_is_mesh(&sdata->vif)) {
-                int meshhdrlen = ieee80211_get_mesh_hdrlen(
+        if (ieee80211_vif_is_mesh(&sdata->vif))
+                hdrlen += ieee80211_get_mesh_hdrlen(
                                 (struct ieee80211s_hdr *) (skb->data + hdrlen));
-                /* Copy on cb:
-                 *  - mesh header: to be used for mesh forwarding
-                 * decision. It will also be used as mesh header template at
-                 * tx.c:ieee80211_subif_start_xmit() if interface
-                 * type is mesh and skb->pkt_type == PACKET_OTHERHOST
-                 *  - ta: to be used if a RERR needs to be sent.
-                 */
-                memcpy(skb->cb, skb->data + hdrlen, meshhdrlen);
-                memcpy(MESH_PREQ(skb), hdr->addr2, ETH_ALEN);
-                hdrlen += meshhdrlen;
-        }
 
         /* convert IEEE 802.11 header + possible LLC headers into Ethernet
          * header
@@ -1269,38 +1258,6 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
                 }
         }
 
-        /* Mesh forwarding */
-        if (ieee80211_vif_is_mesh(&sdata->vif)) {
-                u8 *mesh_ttl = &((struct ieee80211s_hdr *)skb->cb)->ttl;
-                (*mesh_ttl)--;
-
-                if (is_multicast_ether_addr(skb->data)) {
-                        if (*mesh_ttl > 0) {
-                                xmit_skb = skb_copy(skb, GFP_ATOMIC);
-                                if (xmit_skb)
-                                        xmit_skb->pkt_type = PACKET_OTHERHOST;
-                                else if (net_ratelimit())
-                                        printk(KERN_DEBUG "%s: failed to clone "
-                                               "multicast frame\n", dev->name);
-                        } else
-                                IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.sta,
-                                                             dropped_frames_ttl);
-                } else if (skb->pkt_type != PACKET_OTHERHOST &&
-                        compare_ether_addr(dev->dev_addr, skb->data) != 0) {
-                        if (*mesh_ttl == 0) {
-                                IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.sta,
-                                                             dropped_frames_ttl);
-                                dev_kfree_skb(skb);
-                                skb = NULL;
-                        } else {
-                                xmit_skb = skb;
-                                xmit_skb->pkt_type = PACKET_OTHERHOST;
-                                if (!(dev->flags & IFF_PROMISC))
-                                        skb  = NULL;
-                        }
-                }
-        }
-
         if (skb) {
                 /* deliver to local stack */
                 skb->protocol = eth_type_trans(skb, dev);
@@ -1431,6 +1388,63 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
 }
 
 static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
+{
+        struct ieee80211_hdr *hdr;
+        struct ieee80211s_hdr *mesh_hdr;
+        unsigned int hdrlen;
+        struct sk_buff *skb = rx->skb, *fwd_skb;
+
+        hdr = (struct ieee80211_hdr *) skb->data;
+        hdrlen = ieee80211_hdrlen(hdr->frame_control);
+        mesh_hdr = (struct ieee80211s_hdr *) (skb->data + hdrlen);
+
+        if (!ieee80211_is_data(hdr->frame_control))
+                return RX_CONTINUE;
+
+        if (!mesh_hdr->ttl)
+                /* illegal frame */
+                return RX_DROP_MONITOR;
+
+        if (compare_ether_addr(rx->dev->dev_addr, hdr->addr3) == 0)
+                return RX_CONTINUE;
+
+        mesh_hdr->ttl--;
+
+        if (rx->flags & IEEE80211_RX_RA_MATCH) {
+                if (!mesh_hdr->ttl)
+                        IEEE80211_IFSTA_MESH_CTR_INC(&rx->sdata->u.sta,
+                                                     dropped_frames_ttl);
+                else {
+                        struct ieee80211_hdr *fwd_hdr;
+                        fwd_skb = skb_copy(skb, GFP_ATOMIC);
+
+                        if (!fwd_skb && net_ratelimit())
+                                printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
+                                                   rx->dev->name);
+
+                        fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
+                        /*
+                         * Save TA to addr1 to send TA a path error if a
+                         * suitable next hop is not found
+                         */
+                        memcpy(fwd_hdr->addr1, fwd_hdr->addr2, ETH_ALEN);
+                        memcpy(fwd_hdr->addr2, rx->dev->dev_addr, ETH_ALEN);
+                        fwd_skb->dev = rx->local->mdev;
+                        fwd_skb->iif = rx->dev->ifindex;
+                        dev_queue_xmit(fwd_skb);
+                }
+        }
+
+        if (is_multicast_ether_addr(hdr->addr3) ||
+            rx->dev->flags & IFF_PROMISC)
+                return RX_CONTINUE;
+        else
+                return RX_DROP_MONITOR;
+}
+
+
+static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
 {
         struct net_device *dev = rx->dev;
@@ -1663,10 +1677,12 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata,
         rx->sdata = sdata;
         rx->dev = sdata->dev;
 
-#define CALL_RXH(rxh)           \
-        res = rxh(rx);          \
-        if (res != RX_CONTINUE) \
-                goto rxh_done;
+#define CALL_RXH(rxh)                   \
+        do {                            \
+                res = rxh(rx);          \
+                if (res != RX_CONTINUE) \
+                        goto rxh_done;  \
+        } while (0);
 
         CALL_RXH(ieee80211_rx_h_passive_scan)
         CALL_RXH(ieee80211_rx_h_check)
@@ -1678,6 +1694,8 @@ static void ieee80211_invoke_rx_handlers(struct ieee80211_sub_if_data *sdata,
         /* must be after MMIC verify so header is counted in MPDU mic */
         CALL_RXH(ieee80211_rx_h_remove_qos_control)
         CALL_RXH(ieee80211_rx_h_amsdu)
+        if (ieee80211_vif_is_mesh(&sdata->vif))
+                CALL_RXH(ieee80211_rx_h_mesh_fwding);
         CALL_RXH(ieee80211_rx_h_data)
         CALL_RXH(ieee80211_rx_h_ctrl)
         CALL_RXH(ieee80211_rx_h_mgmt)