mac80211: don't initiate path discovery when forwarding frame with unknown DA
We used to initiate a path discovery when receiving a frame for which
there is no forwarding information. To cut down on PREQ spam, just send
a (gated) PERR in response.
Also separate path discovery logic from nexthop querying. This patch
means we no longer queue frames when forwarding, so kill the PERR TX
stuff in discard_frame().
Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index 622cc96..bd14bd2 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -233,6 +233,8 @@
/* Mesh paths */
int mesh_nexthop_lookup(struct sk_buff *skb,
struct ieee80211_sub_if_data *sdata);
+int mesh_nexthop_resolve(struct sk_buff *skb,
+ struct ieee80211_sub_if_data *sdata);
void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata);
struct mesh_path *mesh_path_lookup(u8 *dst,
struct ieee80211_sub_if_data *sdata);
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index fe93386..73abb75 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -982,72 +982,97 @@
kfree(preq_node);
}
-/**
- * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
+/* mesh_nexthop_resolve - lookup next hop for given skb and start path
+ * discovery if no forwarding information is found.
*
* @skb: 802.11 frame to be sent
* @sdata: network subif the frame will be sent through
*
- * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
- * found, the function will start a path discovery and queue the frame so it is
- * sent when the path is resolved. This means the caller must not free the skb
- * in this case.
+ * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
+ * skb is freeed here if no mpath could be allocated.
*/
-int mesh_nexthop_lookup(struct sk_buff *skb,
- struct ieee80211_sub_if_data *sdata)
+int mesh_nexthop_resolve(struct sk_buff *skb,
+ struct ieee80211_sub_if_data *sdata)
{
- struct sk_buff *skb_to_free = NULL;
- struct mesh_path *mpath;
- struct sta_info *next_hop;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct mesh_path *mpath;
+ struct sk_buff *skb_to_free = NULL;
u8 *target_addr = hdr->addr3;
int err = 0;
rcu_read_lock();
- mpath = mesh_path_lookup(target_addr, sdata);
+ err = mesh_nexthop_lookup(skb, sdata);
+ if (!err)
+ goto endlookup;
+ /* no nexthop found, start resolving */
+ mpath = mesh_path_lookup(target_addr, sdata);
if (!mpath) {
mesh_path_add(target_addr, sdata);
mpath = mesh_path_lookup(target_addr, sdata);
if (!mpath) {
- sdata->u.mesh.mshstats.dropped_frames_no_route++;
+ mesh_path_discard_frame(skb, sdata);
err = -ENOSPC;
goto endlookup;
}
}
- if (mpath->flags & MESH_PATH_ACTIVE) {
- if (time_after(jiffies,
- mpath->exp_time -
- msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
- !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
- !(mpath->flags & MESH_PATH_RESOLVING) &&
- !(mpath->flags & MESH_PATH_FIXED)) {
- mesh_queue_preq(mpath,
- PREQ_Q_F_START | PREQ_Q_F_REFRESH);
- }
- next_hop = rcu_dereference(mpath->next_hop);
- if (next_hop) {
- memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
- memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
- } else
- err = -ENOENT;
- } else {
- struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
- if (!(mpath->flags & MESH_PATH_RESOLVING)) {
- /* Start discovery only if it is not running yet */
- mesh_queue_preq(mpath, PREQ_Q_F_START);
- }
+ if (!(mpath->flags & MESH_PATH_RESOLVING))
+ mesh_queue_preq(mpath, PREQ_Q_F_START);
- if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
- skb_to_free = skb_dequeue(&mpath->frame_queue);
+ if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
+ skb_to_free = skb_dequeue(&mpath->frame_queue);
- info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
- ieee80211_set_qos_hdr(sdata, skb);
- skb_queue_tail(&mpath->frame_queue, skb);
- if (skb_to_free)
- mesh_path_discard_frame(skb_to_free, sdata);
- err = -ENOENT;
+ info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
+ ieee80211_set_qos_hdr(sdata, skb);
+ skb_queue_tail(&mpath->frame_queue, skb);
+ err = -ENOENT;
+ if (skb_to_free)
+ mesh_path_discard_frame(skb_to_free, sdata);
+
+endlookup:
+ rcu_read_unlock();
+ return err;
+}
+/**
+ * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
+ * this function is considered "using" the associated mpath, so preempt a path
+ * refresh if this mpath expires soon.
+ *
+ * @skb: 802.11 frame to be sent
+ * @sdata: network subif the frame will be sent through
+ *
+ * Returns: 0 if the next hop was found. Nonzero otherwise.
+ */
+int mesh_nexthop_lookup(struct sk_buff *skb,
+ struct ieee80211_sub_if_data *sdata)
+{
+ struct mesh_path *mpath;
+ struct sta_info *next_hop;
+ struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+ u8 *target_addr = hdr->addr3;
+ int err = -ENOENT;
+
+ rcu_read_lock();
+ mpath = mesh_path_lookup(target_addr, sdata);
+
+ if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
+ goto endlookup;
+
+ if (time_after(jiffies,
+ mpath->exp_time -
+ msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
+ !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
+ !(mpath->flags & MESH_PATH_RESOLVING) &&
+ !(mpath->flags & MESH_PATH_FIXED))
+ mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
+
+ next_hop = rcu_dereference(mpath->next_hop);
+ if (next_hop) {
+ memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
+ memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
+ err = 0;
}
endlookup:
diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 4c50d8a..edf167e 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -973,38 +973,11 @@
* @skb: frame to discard
* @sdata: network subif the frame was to be sent through
*
- * If the frame was being forwarded from another MP, a PERR frame will be sent
- * to the precursor. The precursor's address (i.e. the previous hop) was saved
- * in addr1 of the frame-to-be-forwarded, and would only be overwritten once
- * the destination is successfully resolved.
- *
* Locking: the function must me called within a rcu_read_lock region
*/
void mesh_path_discard_frame(struct sk_buff *skb,
struct ieee80211_sub_if_data *sdata)
{
- struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
- struct mesh_path *mpath;
- u32 sn = 0;
- __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_NOFORWARD);
-
- if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
- u8 *ra, *da;
-
- da = hdr->addr3;
- ra = hdr->addr2;
- rcu_read_lock();
- mpath = mesh_path_lookup(da, sdata);
- if (mpath) {
- spin_lock_bh(&mpath->state_lock);
- sn = ++mpath->sn;
- spin_unlock_bh(&mpath->state_lock);
- }
- rcu_read_unlock();
- mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, da,
- cpu_to_le32(sn), reason, ra, sdata);
- }
-
kfree_skb(skb);
sdata->u.mesh.mshstats.dropped_frames_no_route++;
}
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 92fa9574..f842f90 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1899,6 +1899,7 @@
struct ieee80211_local *local = rx->local;
struct ieee80211_sub_if_data *sdata = rx->sdata;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+ __le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_NOFORWARD);
u16 q;
hdr = (struct ieee80211_hdr *) skb->data;
@@ -1985,13 +1986,14 @@
fwded_mcast);
memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
} else {
- int err;
- err = mesh_nexthop_lookup(fwd_skb, sdata);
- /* Failed to immediately resolve next hop:
- * fwded frame was dropped or will be added
- * later to the pending skb queue. */
- if (err)
+ if (mesh_nexthop_lookup(fwd_skb, sdata)) {
+ /* can't resolve next hop, send a PERR */
+ mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
+ fwd_hdr->addr3, 0, reason,
+ fwd_hdr->addr2, sdata);
+ sdata->u.mesh.mshstats.dropped_frames_no_route++;
return RX_DROP_MONITOR;
+ }
IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
fwded_unicast);
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 655e3a9..c4cb4a5 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1464,7 +1464,7 @@
if (ieee80211_vif_is_mesh(&sdata->vif) &&
ieee80211_is_data(hdr->frame_control) &&
!is_multicast_ether_addr(hdr->addr1))
- if (mesh_nexthop_lookup(skb, sdata)) {
+ if (mesh_nexthop_resolve(skb, sdata)) {
/* skb queued: don't free */
rcu_read_unlock();
return;
