From: Jesse Jones <[email protected]> When more than one station hears a broadcast request, it is possible that multiple devices will reply at the same time, potentially causing collision. This patch helps reduce this issue.
Signed-off-by: Alexis Green <[email protected]> Signed-off-by: Benjamin Morgan <[email protected]> --- net/mac80211/ieee80211_i.h | 11 ++++ net/mac80211/iface.c | 58 +++++++++++++++++++++ net/mac80211/mesh.c | 2 + net/mac80211/mesh_hwmp.c | 124 +++++++++++++++++++++++++++++++++++---------- 4 files changed, 168 insertions(+), 27 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 159a1a7..f422897 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -330,6 +330,11 @@ struct mesh_preq_queue { u8 flags; }; +struct mesh_tx_queue { + struct list_head list; + struct sk_buff *skb; +}; + struct ieee80211_roc_work { struct list_head list; @@ -670,6 +675,11 @@ struct ieee80211_if_mesh { spinlock_t mesh_preq_queue_lock; struct mesh_preq_queue preq_queue; int preq_queue_len; + /* Spinlock for MPATH frame tx queue */ + spinlock_t mesh_tx_queue_lock; + struct mesh_tx_queue tx_queue; + int tx_queue_len; + struct mesh_stats mshstats; struct mesh_config mshcfg; atomic_t estab_plinks; @@ -919,6 +929,7 @@ struct ieee80211_sub_if_data { struct work_struct work; struct sk_buff_head skb_queue; + struct delayed_work tx_work; u8 needed_rx_chains; enum ieee80211_smps_mode smps_mode; diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 40813dd..51d5cfa 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -778,6 +778,59 @@ static int ieee80211_open(struct net_device *dev) return ieee80211_do_open(&sdata->wdev, true); } +static void flush_tx_skbs(struct ieee80211_sub_if_data *sdata) +{ + struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; + struct mesh_tx_queue *tx_node; + + spin_lock_bh(&ifmsh->mesh_tx_queue_lock); + + /* Note that this check is important because of the two-stage + * way that ieee80211_if_mesh is initialized. + */ + if (ifmsh->tx_queue_len > 0) { + mhwmp_dbg(sdata, "flushing %d skbs", ifmsh->tx_queue_len); + + while (!list_empty(&ifmsh->tx_queue.list)) { + tx_node = list_last_entry(&ifmsh->tx_queue.list, + struct mesh_tx_queue, list); + kfree_skb(tx_node->skb); + list_del(&tx_node->list); + kfree(tx_node); + } + ifmsh->tx_queue_len = 0; + } + + spin_unlock_bh(&ifmsh->mesh_tx_queue_lock); +} + +static void mesh_jittered_tx(struct work_struct *wk) +{ + struct ieee80211_sub_if_data *sdata = + container_of( + wk, struct ieee80211_sub_if_data, + tx_work.work); + + struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; + struct mesh_tx_queue *tx_node; + + spin_lock_bh(&ifmsh->mesh_tx_queue_lock); + + list_for_each_entry(tx_node, &ifmsh->tx_queue.list, list) { + ieee80211_tx_skb(sdata, tx_node->skb); + } + + while (!list_empty(&ifmsh->tx_queue.list)) { + tx_node = list_last_entry(&ifmsh->tx_queue.list, + struct mesh_tx_queue, list); + list_del(&tx_node->list); + kfree(tx_node); + } + ifmsh->tx_queue_len = 0; + + spin_unlock_bh(&ifmsh->mesh_tx_queue_lock); +} + static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, bool going_down) { @@ -881,6 +934,9 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, cancel_delayed_work_sync(&sdata->dfs_cac_timer_work); + flush_tx_skbs(sdata); + cancel_delayed_work_sync(&sdata->tx_work); + if (sdata->wdev.cac_started) { chandef = sdata->vif.bss_conf.chandef; WARN_ON(local->suspended); @@ -1846,6 +1902,8 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name, ieee80211_dfs_cac_timer_work); INIT_DELAYED_WORK(&sdata->dec_tailroom_needed_wk, ieee80211_delayed_tailroom_dec); + INIT_DELAYED_WORK(&sdata->tx_work, + mesh_jittered_tx); for (i = 0; i < NUM_NL80211_BANDS; i++) { struct ieee80211_supported_band *sband; diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index c28b0af..f0d3cd9 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -1381,6 +1381,8 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata) ieee80211_mesh_path_root_timer, (unsigned long) sdata); INIT_LIST_HEAD(&ifmsh->preq_queue.list); + INIT_LIST_HEAD(&ifmsh->tx_queue.list); + spin_lock_init(&ifmsh->mesh_tx_queue_lock); skb_queue_head_init(&ifmsh->ps.bc_buf); spin_lock_init(&ifmsh->mesh_preq_queue_lock); spin_lock_init(&ifmsh->sync_offset_lock); diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c index b747c96..2f8ca4a 100644 --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -18,6 +18,7 @@ #define ARITH_SHIFT 8 #define MAX_PREQ_QUEUE_LEN 64 +#define MAX_TX_QUEUE_LEN 8 static void mesh_queue_preq(struct mesh_path *, u8); @@ -98,13 +99,15 @@ enum mpath_frame_type { static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; -static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, - const u8 *orig_addr, u32 orig_sn, - u8 target_flags, const u8 *target, - u32 target_sn, const u8 *da, - u8 hop_count, u8 ttl, - u32 lifetime, u32 metric, u32 preq_id, - struct ieee80211_sub_if_data *sdata) +static struct sk_buff *alloc_mesh_path_sel_frame(enum mpath_frame_type action, + u8 flags, const u8 *orig_addr, + u32 orig_sn, u8 target_flags, + const u8 *target, + u32 target_sn, const u8 *da, + u8 hop_count, u8 ttl, + u32 lifetime, u32 metric, + u32 preq_id, + struct ieee80211_sub_if_data *sdata) { struct ieee80211_local *local = sdata->local; struct sk_buff *skb; @@ -117,7 +120,7 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, hdr_len + 2 + 37); /* max HWMP IE */ if (!skb) - return -1; + return NULL; skb_reserve(skb, local->tx_headroom); mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len); memset(mgmt, 0, hdr_len); @@ -153,7 +156,7 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, break; default: kfree_skb(skb); - return -ENOTSUPP; + return NULL; } *pos++ = ie_len; *pos++ = flags; @@ -192,10 +195,72 @@ static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, pos += 4; } - ieee80211_tx_skb(sdata, skb); - return 0; + return skb; +} + +static void mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags, + const u8 *orig_addr, u32 orig_sn, + u8 target_flags, const u8 *target, + u32 target_sn, const u8 *da, + u8 hop_count, u8 ttl, + u32 lifetime, u32 metric, u32 preq_id, + struct ieee80211_sub_if_data *sdata) +{ + struct sk_buff *skb = alloc_mesh_path_sel_frame(action, flags, + orig_addr, orig_sn, target_flags, target, target_sn, + da, hop_count, ttl, lifetime, metric, preq_id, sdata); + if (skb) + ieee80211_tx_skb(sdata, skb); } +static void mesh_path_sel_frame_tx_jittered(enum mpath_frame_type action, + u8 flags, const u8 *orig_addr, + u32 orig_sn, u8 target_flags, + const u8 *target, u32 target_sn, + const u8 *da, u8 hop_count, u8 ttl, + u32 lifetime, u32 metric, + u32 preq_id, + struct ieee80211_sub_if_data *sdata) +{ + u32 jitter; + struct sk_buff *skb = alloc_mesh_path_sel_frame(action, flags, + orig_addr, orig_sn, + target_flags, target, + target_sn, da, + hop_count, ttl, + lifetime, metric, + preq_id, sdata); + if (skb) { + struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; + struct mesh_tx_queue *tx_node = kmalloc( + sizeof(struct mesh_tx_queue), GFP_ATOMIC); + if (!tx_node) { + mhwmp_dbg(sdata, "could not allocate mesh_hwmp tx node"); + return; + } + + spin_lock_bh(&ifmsh->mesh_tx_queue_lock); + if (ifmsh->tx_queue_len == MAX_TX_QUEUE_LEN) { + spin_unlock_bh(&ifmsh->mesh_tx_queue_lock); + kfree(tx_node); + kfree_skb(skb); + if (printk_ratelimit()) + mhwmp_dbg(sdata, "mesh_hwmp tx node queue full"); + return; + } + + tx_node->skb = skb; + list_add_tail(&tx_node->list, &ifmsh->tx_queue.list); + ++ifmsh->tx_queue_len; + spin_unlock_bh(&ifmsh->mesh_tx_queue_lock); + + jitter = prandom_u32() % 25; + + ieee80211_queue_delayed_work( + &sdata->local->hw, + &sdata->tx_work, msecs_to_jiffies(jitter)); + } +} /* Headroom is not adjusted. Caller should ensure that skb has sufficient * headroom in case the frame is encrypted. */ @@ -611,11 +676,13 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata, ttl = ifmsh->mshcfg.element_ttl; if (ttl != 0) { mhwmp_dbg(sdata, "replying to the PREQ\n"); - mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr, - orig_sn, 0, target_addr, - target_sn, mgmt->sa, 0, ttl, - lifetime, target_metric, 0, - sdata); + mesh_path_sel_frame_tx_jittered(MPATH_PREP, 0, + orig_addr, orig_sn, + 0, target_addr, + target_sn, mgmt->sa, + 0, ttl, lifetime, + target_metric, 0, + sdata); } else { ifmsh->mshstats.dropped_frames_ttl++; } @@ -643,10 +710,11 @@ static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata, target_sn = PREQ_IE_TARGET_SN(preq_elem); } - mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr, - orig_sn, target_flags, target_addr, - target_sn, da, hopcount, ttl, lifetime, - orig_metric, preq_id, sdata); + mesh_path_sel_frame_tx_jittered(MPATH_PREQ, flags, orig_addr, + orig_sn, target_flags, + target_addr, target_sn, da, + hopcount, ttl, lifetime, + orig_metric, preq_id, sdata); if (!is_multicast_ether_addr(da)) ifmsh->mshstats.fwded_unicast++; else @@ -712,9 +780,10 @@ static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata, target_sn = PREP_IE_TARGET_SN(prep_elem); orig_sn = PREP_IE_ORIG_SN(prep_elem); - mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0, - target_addr, target_sn, next_hop, hopcount, - ttl, lifetime, metric, 0, sdata); + mesh_path_sel_frame_tx_jittered(MPATH_PREP, flags, orig_addr, orig_sn, + 0, target_addr, target_sn, next_hop, + hopcount, ttl, lifetime, metric, 0, + sdata); rcu_read_unlock(); sdata->u.mesh.mshstats.fwded_unicast++; @@ -864,10 +933,11 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata, ttl--; if (ifmsh->mshcfg.dot11MeshForwarding) { - mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr, - orig_sn, 0, NULL, 0, broadcast_addr, - hopcount, ttl, interval, - metric + metric_txsta, 0, sdata); + mesh_path_sel_frame_tx_jittered(MPATH_RANN, flags, orig_addr, + orig_sn, 0, NULL, 0, + broadcast_addr, hopcount, ttl, + interval, metric + metric_txsta, + 0, sdata); } rcu_read_unlock();
