From 0cfda8519c85eb279166fb55a8553ee66eac9b35 Mon Sep 17 00:00:00 2001 From: Thomas Pedersen Date: Thu, 24 Nov 2011 17:15:25 -0800 Subject: 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 Signed-off-by: John W. Linville --- net/mac80211/mesh.h | 2 + net/mac80211/mesh_hwmp.c | 111 +++++++++++++++++++++++++++----------------- net/mac80211/mesh_pathtbl.c | 27 ----------- net/mac80211/rx.c | 14 +++--- net/mac80211/tx.c | 2 +- 5 files changed, 79 insertions(+), 77 deletions(-) (limited to 'net') diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h index 622cc96eb4de..bd14bd26a2b6 100644 --- a/net/mac80211/mesh.h +++ b/net/mac80211/mesh.h @@ -233,6 +233,8 @@ void ieee80211_mesh_root_setup(struct ieee80211_if_mesh *ifmsh); /* 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 fe93386d6aa9..73abb7524b2c 100644 --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -982,72 +982,97 @@ enddiscovery: 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); + + 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; - if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN) - skb_to_free = skb_dequeue(&mpath->frame_queue); + 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); - 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; + 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 4c50d8ade04f..edf167e3b8f3 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -973,38 +973,11 @@ int mesh_path_send_to_gates(struct mesh_path *mpath) * @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 92fa95741761..f842f901d179 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1899,6 +1899,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) 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 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) 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 655e3a97f92e..c4cb4a536e27 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1464,7 +1464,7 @@ void ieee80211_xmit(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) 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; -- cgit v1.2.3-59-g8ed1b