OpenBSD 11n APs currently enforce HT protection (RTS) for all frames.
This made the initial 11n hostap implementation easier for me.
Sending RTS frames implies unnecessary overhead for data frames.
HT protection is only required if any non-HT devices (11a/b/g) are around.
Our node cache contains information about all nodes in the environment and
checking whether non-HT nodes are present while cleaning this cache is cheap.
This cache used to be cleaned once per hour. This diff changes the interval
to 30 seconds for timely HT protection updates.
I have not done any performance testing with this diff.
The wireless stack defaults to RTS for frames over 512 bytes regardless
of HT protection settings. While this change should improve latency for
small frames in 11n-only environments I don't expect an increase in bulk
throughput when sending data to clients.
Index: ieee80211_node.c
===================================================================
RCS file: /cvs/src/sys/net80211/ieee80211_node.c,v
retrieving revision 1.114
diff -u -p -r1.114 ieee80211_node.c
--- ieee80211_node.c 3 Feb 2017 09:32:26 -0000 1.114
+++ ieee80211_node.c 2 Mar 2017 11:52:18 -0000
@@ -359,10 +359,8 @@ ieee80211_create_ibss(struct ieee80211co
int aci;
/*
- * Default to non-member HT protection until we have a way
- * of picking up information from the environment (such as
- * beacons from other networks) which proves that only HT
- * STAs are on the air.
+ * Default to non-member HT protection. This will be updated
+ * later based on the number of non-HT nodes in the node cache.
*/
ni->ni_htop1 = IEEE80211_HTPROT_NONMEMBER;
ic->ic_protmode = IEEE80211_PROT_RTSCTS;
@@ -1210,7 +1208,7 @@ ieee80211_clean_cached(struct ieee80211c
*
* If called because of a cache timeout, which happens only in hostap and ibss
* modes, clean all inactive cached or authenticated nodes but don't de-auth
- * any associated nodes.
+ * any associated nodes. Also update HT protection settings.
*
* Else, this function is called because a new node must be allocated but the
* node cache is full. In this case, return as soon as a free slot was made
@@ -1225,8 +1223,10 @@ ieee80211_clean_nodes(struct ieee80211co
u_int gen = ic->ic_scangen++; /* NB: ok 'cuz single-threaded*/
int s;
#ifndef IEEE80211_STA_ONLY
- int nnodes = 0;
+ int nnodes = 0, nonht = 0, nonhtassoc = 0;
struct ifnet *ifp = &ic->ic_if;
+ enum ieee80211_htprot htprot = IEEE80211_HTPROT_NONE;
+ enum ieee80211_protmode protmode = IEEE80211_PROT_NONE;
#endif
s = splnet();
@@ -1239,6 +1239,13 @@ ieee80211_clean_nodes(struct ieee80211co
continue;
#ifndef IEEE80211_STA_ONLY
nnodes++;
+ if ((ic->ic_flags & IEEE80211_F_HTON) && cache_timeout) {
+ if ((ni->ni_rxmcs[0] & 0xff) == 0) {
+ nonht++;
+ if (ni->ni_state == IEEE80211_STA_ASSOC)
+ nonhtassoc++;
+ }
+ }
#endif
ni->ni_scangen = gen;
if (ni->ni_refcnt > 0)
@@ -1278,14 +1285,19 @@ ieee80211_clean_nodes(struct ieee80211co
*/
#ifndef IEEE80211_STA_ONLY
nnodes--;
+ if ((ic->ic_flags & IEEE80211_F_HTON) && cache_timeout) {
+ if ((ni->ni_rxmcs[0] & 0xff) == 0) {
+ nonht--;
+ if (ni->ni_state == IEEE80211_STA_ASSOC)
+ nonhtassoc--;
+ }
+ }
if (ic->ic_opmode == IEEE80211_M_HOSTAP &&
ni->ni_state >= IEEE80211_STA_AUTH &&
ni->ni_state != IEEE80211_STA_COLLECT) {
- splx(s);
IEEE80211_SEND_MGMT(ic, ni,
IEEE80211_FC0_SUBTYPE_DEAUTH,
IEEE80211_REASON_AUTH_EXPIRE);
- s = splnet();
ieee80211_node_leave(ic, ni);
} else
#endif
@@ -1294,6 +1306,23 @@ ieee80211_clean_nodes(struct ieee80211co
}
#ifndef IEEE80211_STA_ONLY
+ if ((ic->ic_flags & IEEE80211_F_HTON) && cache_timeout) {
+ /* Update HT protection settings. */
+ if (nonht) {
+ protmode = IEEE80211_PROT_RTSCTS;
+ if (nonhtassoc)
+ htprot = IEEE80211_HTPROT_NONHT_MIXED;
+ else
+ htprot = IEEE80211_HTPROT_NONMEMBER;
+ }
+ if (ic->ic_bss->ni_htop1 != htprot) {
+ ic->ic_bss->ni_htop1 = htprot;
+ ic->ic_protmode = protmode;
+ if (ic->ic_update_htprot)
+ ic->ic_update_htprot(ic, ic->ic_bss);
+ }
+ }
+
/*
* During a cache timeout we iterate over all nodes.
* Check for node leaks by comparing the actual number of cached
@@ -1550,18 +1579,6 @@ ieee80211_count_nonerpsta(void *arg, str
}
void
-ieee80211_count_nonhtsta(void *arg, struct ieee80211_node *ni)
-{
- int *nonhtsta = arg;
-
- if (ni->ni_associd == 0 || ni->ni_state == IEEE80211_STA_COLLECT)
- return;
-
- if (!(ni->ni_flags & IEEE80211_NODE_HT))
- (*nonhtsta)++;
-}
-
-void
ieee80211_count_pssta(void *arg, struct ieee80211_node *ni)
{
int *pssta = arg;
@@ -1833,17 +1850,6 @@ ieee80211_node_leave(struct ieee80211com
if (ni->ni_flags & IEEE80211_NODE_HT)
ieee80211_node_leave_ht(ic, ni);
- else if (ic->ic_flags & IEEE80211_F_HTON) {
- int nonhtsta = 0;
- ieee80211_iterate_nodes(ic,
- ieee80211_count_nonhtsta, &nonhtsta);
- if (nonhtsta == 1) {
- /* All associated stations now support HT. */
- ic->ic_bss->ni_htop1 = IEEE80211_HTPROT_NONMEMBER;
- if (ic->ic_update_htprot)
- ic->ic_update_htprot(ic, ic->ic_bss);
- }
- }
if (ic->ic_node_leave != NULL)
(*ic->ic_node_leave)(ic, ni);
Index: ieee80211_node.h
===================================================================
RCS file: /cvs/src/sys/net80211/ieee80211_node.h,v
retrieving revision 1.66
diff -u -p -r1.66 ieee80211_node.h
--- ieee80211_node.h 1 Mar 2017 19:28:48 -0000 1.66
+++ ieee80211_node.h 2 Mar 2017 11:28:17 -0000
@@ -40,7 +40,7 @@
#define IEEE80211_INACT_WAIT 5 /* inactivity timer
interval */
#define IEEE80211_INACT_MAX (300/IEEE80211_INACT_WAIT)
#define IEEE80211_CACHE_SIZE 100
-#define IEEE80211_CACHE_WAIT 3600
+#define IEEE80211_CACHE_WAIT 30
struct ieee80211_rateset {
u_int8_t rs_nrates;
@@ -380,7 +380,6 @@ extern int ieee80211_setup_rates(struct
extern int ieee80211_iserp_sta(const struct ieee80211_node *);
extern void ieee80211_count_longslotsta(void *, struct ieee80211_node *);
extern void ieee80211_count_nonerpsta(void *, struct ieee80211_node *);
-extern void ieee80211_count_nonhtsta(void *, struct ieee80211_node *);
extern void ieee80211_count_pssta(void *, struct ieee80211_node *);
extern void ieee80211_count_rekeysta(void *, struct ieee80211_node *);
extern void ieee80211_node_join(struct ieee80211com *,
