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>
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dca7e9430c
Коммит
0cfda8519c
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@ -233,6 +233,8 @@ void ieee80211_mesh_root_setup(struct ieee80211_if_mesh *ifmsh);
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/* Mesh paths */
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int mesh_nexthop_lookup(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata);
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int mesh_nexthop_resolve(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata);
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void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata);
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struct mesh_path *mesh_path_lookup(u8 *dst,
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struct ieee80211_sub_if_data *sdata);
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@ -982,72 +982,97 @@ enddiscovery:
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kfree(preq_node);
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}
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/**
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* mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
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/* mesh_nexthop_resolve - lookup next hop for given skb and start path
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* discovery if no forwarding information is found.
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*
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* @skb: 802.11 frame to be sent
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* @sdata: network subif the frame will be sent through
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*
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* Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
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* found, the function will start a path discovery and queue the frame so it is
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* sent when the path is resolved. This means the caller must not free the skb
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* in this case.
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* Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
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* skb is freeed here if no mpath could be allocated.
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*/
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int mesh_nexthop_lookup(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata)
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int mesh_nexthop_resolve(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata)
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{
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struct sk_buff *skb_to_free = NULL;
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struct mesh_path *mpath;
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struct sta_info *next_hop;
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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struct mesh_path *mpath;
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struct sk_buff *skb_to_free = NULL;
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u8 *target_addr = hdr->addr3;
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int err = 0;
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rcu_read_lock();
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mpath = mesh_path_lookup(target_addr, sdata);
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err = mesh_nexthop_lookup(skb, sdata);
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if (!err)
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goto endlookup;
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/* no nexthop found, start resolving */
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mpath = mesh_path_lookup(target_addr, sdata);
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if (!mpath) {
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mesh_path_add(target_addr, sdata);
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mpath = mesh_path_lookup(target_addr, sdata);
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if (!mpath) {
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sdata->u.mesh.mshstats.dropped_frames_no_route++;
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mesh_path_discard_frame(skb, sdata);
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err = -ENOSPC;
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goto endlookup;
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}
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}
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if (mpath->flags & MESH_PATH_ACTIVE) {
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if (time_after(jiffies,
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mpath->exp_time -
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msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
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!memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
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!(mpath->flags & MESH_PATH_RESOLVING) &&
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!(mpath->flags & MESH_PATH_FIXED)) {
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mesh_queue_preq(mpath,
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PREQ_Q_F_START | PREQ_Q_F_REFRESH);
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}
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next_hop = rcu_dereference(mpath->next_hop);
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if (next_hop) {
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memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
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memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
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} else
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err = -ENOENT;
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} else {
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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if (!(mpath->flags & MESH_PATH_RESOLVING)) {
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/* Start discovery only if it is not running yet */
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mesh_queue_preq(mpath, PREQ_Q_F_START);
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}
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if (!(mpath->flags & MESH_PATH_RESOLVING))
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mesh_queue_preq(mpath, PREQ_Q_F_START);
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if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
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skb_to_free = skb_dequeue(&mpath->frame_queue);
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if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
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skb_to_free = skb_dequeue(&mpath->frame_queue);
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info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
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ieee80211_set_qos_hdr(sdata, skb);
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skb_queue_tail(&mpath->frame_queue, skb);
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if (skb_to_free)
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mesh_path_discard_frame(skb_to_free, sdata);
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err = -ENOENT;
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info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
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ieee80211_set_qos_hdr(sdata, skb);
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skb_queue_tail(&mpath->frame_queue, skb);
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err = -ENOENT;
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if (skb_to_free)
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mesh_path_discard_frame(skb_to_free, sdata);
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endlookup:
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rcu_read_unlock();
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return err;
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}
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/**
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* mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
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* this function is considered "using" the associated mpath, so preempt a path
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* refresh if this mpath expires soon.
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*
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* @skb: 802.11 frame to be sent
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* @sdata: network subif the frame will be sent through
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*
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* Returns: 0 if the next hop was found. Nonzero otherwise.
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*/
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int mesh_nexthop_lookup(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata)
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{
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struct mesh_path *mpath;
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struct sta_info *next_hop;
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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u8 *target_addr = hdr->addr3;
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int err = -ENOENT;
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rcu_read_lock();
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mpath = mesh_path_lookup(target_addr, sdata);
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if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
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goto endlookup;
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if (time_after(jiffies,
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mpath->exp_time -
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msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
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!memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
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!(mpath->flags & MESH_PATH_RESOLVING) &&
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!(mpath->flags & MESH_PATH_FIXED))
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mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
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next_hop = rcu_dereference(mpath->next_hop);
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if (next_hop) {
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memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
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memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
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err = 0;
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}
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endlookup:
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@ -973,38 +973,11 @@ int mesh_path_send_to_gates(struct mesh_path *mpath)
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* @skb: frame to discard
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* @sdata: network subif the frame was to be sent through
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*
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* If the frame was being forwarded from another MP, a PERR frame will be sent
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* to the precursor. The precursor's address (i.e. the previous hop) was saved
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* in addr1 of the frame-to-be-forwarded, and would only be overwritten once
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* the destination is successfully resolved.
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*
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* Locking: the function must me called within a rcu_read_lock region
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*/
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void mesh_path_discard_frame(struct sk_buff *skb,
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struct ieee80211_sub_if_data *sdata)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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struct mesh_path *mpath;
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u32 sn = 0;
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__le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_NOFORWARD);
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if (memcmp(hdr->addr4, sdata->vif.addr, ETH_ALEN) != 0) {
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u8 *ra, *da;
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da = hdr->addr3;
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ra = hdr->addr2;
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rcu_read_lock();
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mpath = mesh_path_lookup(da, sdata);
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if (mpath) {
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spin_lock_bh(&mpath->state_lock);
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sn = ++mpath->sn;
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spin_unlock_bh(&mpath->state_lock);
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}
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rcu_read_unlock();
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mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl, da,
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cpu_to_le32(sn), reason, ra, sdata);
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}
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kfree_skb(skb);
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sdata->u.mesh.mshstats.dropped_frames_no_route++;
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}
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@ -1899,6 +1899,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
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struct ieee80211_local *local = rx->local;
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struct ieee80211_sub_if_data *sdata = rx->sdata;
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struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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__le16 reason = cpu_to_le16(WLAN_REASON_MESH_PATH_NOFORWARD);
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u16 q;
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hdr = (struct ieee80211_hdr *) skb->data;
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@ -1985,13 +1986,14 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
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fwded_mcast);
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memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
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} else {
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int err;
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err = mesh_nexthop_lookup(fwd_skb, sdata);
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/* Failed to immediately resolve next hop:
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* fwded frame was dropped or will be added
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* later to the pending skb queue. */
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if (err)
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if (mesh_nexthop_lookup(fwd_skb, sdata)) {
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/* can't resolve next hop, send a PERR */
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mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
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fwd_hdr->addr3, 0, reason,
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fwd_hdr->addr2, sdata);
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sdata->u.mesh.mshstats.dropped_frames_no_route++;
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return RX_DROP_MONITOR;
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}
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IEEE80211_IFSTA_MESH_CTR_INC(&sdata->u.mesh,
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fwded_unicast);
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@ -1464,7 +1464,7 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
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if (ieee80211_vif_is_mesh(&sdata->vif) &&
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ieee80211_is_data(hdr->frame_control) &&
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!is_multicast_ether_addr(hdr->addr1))
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if (mesh_nexthop_lookup(skb, sdata)) {
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if (mesh_nexthop_resolve(skb, sdata)) {
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/* skb queued: don't free */
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rcu_read_unlock();
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return;
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