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mac80211: add fast-rx path

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The regular RX path has a lot of code, but with a few
assumptions on the hardware it's possible to reduce the
amount of code significantly. Currently the assumptions
on the driver are the following:
 * hardware/driver reordering buffer (if supporting aggregation)
 * hardware/driver decryption & PN checking (if using encryption)
 * hardware/driver did de-duplication
 * hardware/driver did A-MSDU deaggregation
 * AP_LINK_PS is used (in AP mode)
 * no client powersave handling in mac80211 (in client mode)

of which some are actually checked per packet:
 * de-duplication
 * PN checking
 * decryption
and additionally packets must
 * not be A-MSDU (have been deaggregated by driver/device)
 * be data packets
 * not be fragmented
 * be unicast
 * have RFC 1042 header

Additionally dynamically we assume:
 * no encryption or CCMP/GCMP, TKIP/WEP/other not allowed
 * station must be authorized
 * 4-addr format not enabled

Some data needed for the RX path is cached in a new per-station
"fast_rx" structure, so that we only need to look at this and
the packet, no other memory when processing packets on the fast
RX path.

After doing the above per-packet checks, the data path collapses
down to a pretty simple conversion function taking advantage of
the data cached in the small fast_rx struct.

This should speed up the RX processing, and will make it easier
to reason about parallelizing RX (for which statistics will need
to be per-CPU still.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg
2016-03-31 20:02:10 +03:00
parent 0f9c5a61d4
commit 49ddf8e6e2
8 changed files with 419 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
net/mac80211/cfg.c
View File

@@ -65,11 +65,13 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
return ret;
if (type == NL80211_IFTYPE_AP_VLAN &&
params && params->use_4addr == 0)
params && params->use_4addr == 0) {
RCU_INIT_POINTER(sdata->u.vlan.sta, NULL);
else if (type == NL80211_IFTYPE_STATION &&
params && params->use_4addr >= 0)
ieee80211_check_fast_rx_iface(sdata);
} else if (type == NL80211_IFTYPE_STATION &&
params && params->use_4addr >= 0) {
sdata->u.mgd.use_4addr = params->use_4addr;
}
if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags) {
struct ieee80211_local *local = sdata->local;
@@ -1367,6 +1369,7 @@ static int ieee80211_change_station(struct wiphy *wiphy,
rcu_assign_pointer(vlansdata->u.vlan.sta, sta);
new_4addr = true;
__ieee80211_check_fast_rx_iface(vlansdata);
}
if (sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
@@ -1889,6 +1892,7 @@ static int ieee80211_change_bss(struct wiphy *wiphy,
sdata->flags |= IEEE80211_SDATA_DONT_BRIDGE_PACKETS;
else
sdata->flags &= ~IEEE80211_SDATA_DONT_BRIDGE_PACKETS;
ieee80211_check_fast_rx_iface(sdata);
}
if (params->ht_opmode >= 0) {