diff mbox

[3/3] mac80211: select an AID when creating new mesh STAs

Message ID 1435843690-2856-4-git-send-email-me@bobcopeland.com (mailing list archive)
State Superseded
Delegated to: Johannes Berg
Headers show

Commit Message

Bob Copeland July 2, 2015, 1:28 p.m. UTC
Instead of using peer link id for AID, generate a new
AID when creating mesh STAs in the kernel peering manager.
This enables smaller TIM elements and more closely follows
the standard, and it also enables mesh to work on drivers
that require a valid AID when the STA is inserted (ath10k
firmware has this requirement, for example).

In the case of userspace-managed stations, we use the AID
from NL80211_CMD_NEW_STATION.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
---
 net/mac80211/cfg.c         |  3 +++
 net/mac80211/ieee80211_i.h |  1 +
 net/mac80211/mesh.c        |  7 +++++++
 net/mac80211/mesh_plink.c  | 30 ++++++++++++++++++++++++------
 4 files changed, 35 insertions(+), 6 deletions(-)

Comments

Johannes Berg July 2, 2015, 1:31 p.m. UTC | #1
On Thu, 2015-07-02 at 09:28 -0400, Bob Copeland wrote:
> 
> +	DECLARE_BITMAP(aid_map, IEEE80211_MAX_AID + 1);
> 
Is there really much point in keeping a long-lived bitmap rather than
iterating the existing stations when adding a new one? It's not such a
frequent operation after all.

johannes
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Bob Copeland July 2, 2015, 2:45 p.m. UTC | #2
On Thu, Jul 02, 2015 at 03:31:38PM +0200, Johannes Berg wrote:
> On Thu, 2015-07-02 at 09:28 -0400, Bob Copeland wrote:
> > 
> > +	DECLARE_BITMAP(aid_map, IEEE80211_MAX_AID + 1);
> > 
> Is there really much point in keeping a long-lived bitmap rather than
> iterating the existing stations when adding a new one? It's not such a
> frequent operation after all.

Not really -- I tried it both ways initially, and the bitmap ended up
with less code and u.mesh was still (slightly) smaller than u.mgd, but I
agree it does feel kind of bloaty so I'll prep a version the other way.
Johannes Berg July 2, 2015, 2:49 p.m. UTC | #3
On Thu, 2015-07-02 at 10:45 -0400, Bob Copeland wrote:
> On Thu, Jul 02, 2015 at 03:31:38PM +0200, Johannes Berg wrote:
> > On Thu, 2015-07-02 at 09:28 -0400, Bob Copeland wrote:
> > > 
> > > +	DECLARE_BITMAP(aid_map, IEEE80211_MAX_AID + 1);
> > > 
> > Is there really much point in keeping a long-lived bitmap rather 
> > than
> > iterating the existing stations when adding a new one? It's not 
> > such a
> > frequent operation after all.
> 
> Not really -- I tried it both ways initially, and the bitmap ended up
> with less code and u.mesh was still (slightly) smaller than u.mgd, 
> but I agree it does feel kind of bloaty so I'll prep a version the 
> other way.

I was less worried about the bloat part than the "we're maintaining
this data twice" and corruptions/missing some remove paths etc. That
doesn't seem very likely though since it goes through the common
alloc/destroy path, so I guess it's not a problem.

Whichever you prefer really, I don't really mind.

johannes
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diff mbox

Patch

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 5789d8353505..25f0ff84900e 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1027,6 +1027,9 @@  static void sta_apply_mesh_params(struct ieee80211_local *local,
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	u32 changed = 0;
 
+	if (params->aid)
+		set_bit(params->aid, sdata->u.mesh.aid_map);
+
 	if (params->sta_modify_mask & STATION_PARAM_APPLY_PLINK_STATE) {
 		switch (params->plink_state) {
 		case NL80211_PLINK_ESTAB:
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 52930e91c0fd..d691515259a7 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -689,6 +689,7 @@  struct ieee80211_if_mesh {
 	int ps_peers_light_sleep;
 	int ps_peers_deep_sleep;
 	struct ps_data ps;
+	DECLARE_BITMAP(aid_map, IEEE80211_MAX_AID + 1);
 	/* Channel Switching Support */
 	struct mesh_csa_settings __rcu *csa;
 	enum {
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index e06a5ca7c9a9..f26df5fc29c9 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -150,6 +150,9 @@  void mesh_sta_cleanup(struct sta_info *sta)
 	struct ieee80211_sub_if_data *sdata = sta->sdata;
 	u32 changed;
 
+	if (sta->sta.aid)
+		clear_bit(sta->sta.aid, sdata->u.mesh.aid_map);
+
 	/*
 	 * maybe userspace handles peer allocation and peering, but in either
 	 * case the beacon is still generated by the kernel and we might need
@@ -1323,6 +1326,10 @@  void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
 	ifmsh->accepting_plinks = true;
 	atomic_set(&ifmsh->mpaths, 0);
 	mesh_rmc_init(sdata);
+
+	/* reserve aid 0 used for mcast indication */
+	set_bit(0, ifmsh->aid_map);
+
 	ifmsh->last_preq = jiffies;
 	ifmsh->next_perr = jiffies;
 	ifmsh->csa_role = IEEE80211_MESH_CSA_ROLE_NONE;
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 9dca16bd3eb9..deab8be39627 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -421,20 +421,43 @@  out:
 	spin_unlock_bh(&sta->mesh->plink_lock);
 }
 
+static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
+{
+	int aid;
+
+	/* mark first empty bit as used in aid_map and return it */
+	do {
+		aid = find_first_zero_bit(sdata->u.mesh.aid_map,
+					  IEEE80211_MAX_AID + 1);
+	} while (aid <= IEEE80211_MAX_AID &&
+		 test_and_set_bit(aid, sdata->u.mesh.aid_map));
+
+	if (aid > IEEE80211_MAX_AID)
+		return -ENOBUFS;
+
+	return aid;
+}
+
 static struct sta_info *
 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 {
 	struct sta_info *sta;
+	int aid;
 
 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 		return NULL;
 
+	aid = mesh_allocate_aid(sdata);
+	if (aid < 0)
+		return NULL;
+
 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 	if (!sta)
 		return NULL;
 
 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 	sta->sta.wme = true;
+	sta->sta.aid = aid;
 
 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
@@ -658,8 +681,6 @@  static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 
 	do {
 		get_random_bytes(&llid, sizeof(llid));
-		/* for mesh PS we still only have the AID range for TIM bits */
-		llid = (llid % IEEE80211_MAX_AID) + 1;
 	} while (llid_in_use(sdata, llid));
 
 	return llid;
@@ -1068,7 +1089,6 @@  mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
 			goto unlock_rcu;
 		}
 		sta->mesh->plid = plid;
-		sta->sta.aid = plid;
 	} else if (!sta && event == OPN_RJCT) {
 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
 				    mgmt->sa, 0, plid,
@@ -1080,10 +1100,8 @@  mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
 	}
 
 	/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
-	if (!sta->mesh->plid && event == CNF_ACPT) {
+	if (!sta->mesh->plid && event == CNF_ACPT)
 		sta->mesh->plid = plid;
-		sta->sta.aid = sta->mesh->plid;
-	}
 
 	changed |= mesh_plink_fsm(sdata, sta, event);