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mac80211: factor out station lookup from ieee80211_build_hdr()
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In order to look up the RA station earlier to implement a TX
fastpath, factor out the lookup from ieee80211_build_hdr().
To always have a valid station pointer, also move some of the
checks into the new function.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Johannes Berg committed Mar 30, 2015
1 parent 527871d commit 97ffe75
Showing 1 changed file with 118 additions and 70 deletions.
188 changes: 118 additions & 70 deletions net/mac80211/tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1789,6 +1789,91 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
return NETDEV_TX_OK; /* meaning, we dealt with the skb */
}

static inline bool ieee80211_is_tdls_setup(struct sk_buff *skb)
{
u16 ethertype = (skb->data[12] << 8) | skb->data[13];

return ethertype == ETH_P_TDLS &&
skb->len > 14 &&
skb->data[14] == WLAN_TDLS_SNAP_RFTYPE;
}

static int ieee80211_lookup_ra_sta(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb,
struct sta_info **sta_out)
{
struct sta_info *sta;

switch (sdata->vif.type) {
case NL80211_IFTYPE_AP_VLAN:
sta = rcu_dereference(sdata->u.vlan.sta);
if (sta) {
*sta_out = sta;
return 0;
} else if (sdata->wdev.use_4addr) {
return -ENOLINK;
}
/* fall through */
case NL80211_IFTYPE_AP:
case NL80211_IFTYPE_OCB:
case NL80211_IFTYPE_ADHOC:
if (is_multicast_ether_addr(skb->data)) {
*sta_out = ERR_PTR(-ENOENT);
return 0;
}
sta = sta_info_get_bss(sdata, skb->data);
break;
case NL80211_IFTYPE_WDS:
sta = sta_info_get(sdata, sdata->u.wds.remote_addr);
break;
#ifdef CONFIG_MAC80211_MESH
case NL80211_IFTYPE_MESH_POINT:
/* determined much later */
*sta_out = NULL;
return 0;
#endif
case NL80211_IFTYPE_STATION:
if (sdata->wdev.wiphy->flags & WIPHY_FLAG_SUPPORTS_TDLS) {
sta = sta_info_get(sdata, skb->data);
if (sta) {
bool tdls_peer, tdls_auth;

tdls_peer = test_sta_flag(sta,
WLAN_STA_TDLS_PEER);
tdls_auth = test_sta_flag(sta,
WLAN_STA_TDLS_PEER_AUTH);

if (tdls_peer && tdls_auth) {
*sta_out = sta;
return 0;
}

/*
* TDLS link during setup - throw out frames to
* peer. Allow TDLS-setup frames to unauthorized
* peers for the special case of a link teardown
* after a TDLS sta is removed due to being
* unreachable.
*/
if (tdls_peer && !tdls_auth &&
!ieee80211_is_tdls_setup(skb))
return -EINVAL;
}

}

sta = sta_info_get(sdata, sdata->u.mgd.bssid);
if (!sta)
return -ENOLINK;
break;
default:
return -EINVAL;
}

*sta_out = sta ?: ERR_PTR(-ENOENT);
return 0;
}

/**
* ieee80211_build_hdr - build 802.11 header in the given frame
* @sdata: virtual interface to build the header for
Expand All @@ -1809,7 +1894,7 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
*/
static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
struct sk_buff *skb, u32 info_flags,
struct sta_info **sta_out)
struct sta_info *sta)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_tx_info *info;
Expand All @@ -1822,26 +1907,26 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
const u8 *encaps_data;
int encaps_len, skip_header_bytes;
int nh_pos, h_pos;
struct sta_info *sta = NULL;
bool wme_sta = false, authorized = false, tdls_auth = false;
bool tdls_peer = false, tdls_setup_frame = false;
bool wme_sta = false, authorized = false;
bool tdls_peer;
bool multicast;
bool have_station = false;
u16 info_id = 0;
struct ieee80211_chanctx_conf *chanctx_conf;
struct ieee80211_sub_if_data *ap_sdata;
enum ieee80211_band band;
int ret;

if (IS_ERR(sta))
sta = NULL;

/* convert Ethernet header to proper 802.11 header (based on
* operation mode) */
ethertype = (skb->data[12] << 8) | skb->data[13];
fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);

switch (sdata->vif.type) {
case NL80211_IFTYPE_AP_VLAN:
sta = rcu_dereference(sdata->u.vlan.sta);
if (sta) {
if (sdata->wdev.use_4addr) {
fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
/* RA TA DA SA */
memcpy(hdr.addr1, sta->sta.addr, ETH_ALEN);
Expand All @@ -1851,11 +1936,6 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
hdrlen = 30;
authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
wme_sta = sta->sta.wme;
have_station = true;
*sta_out = sta;
} else if (sdata->wdev.use_4addr) {
ret = -ENOLINK;
goto free;
}
ap_sdata = container_of(sdata->bss, struct ieee80211_sub_if_data,
u.ap);
Expand All @@ -1865,7 +1945,7 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
goto free;
}
band = chanctx_conf->def.chan->band;
if (sta)
if (sdata->wdev.use_4addr)
break;
/* fall through */
case NL80211_IFTYPE_AP:
Expand Down Expand Up @@ -1969,44 +2049,15 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
break;
#endif
case NL80211_IFTYPE_STATION:
if (sdata->wdev.wiphy->flags & WIPHY_FLAG_SUPPORTS_TDLS) {
sta = sta_info_get(sdata, skb->data);
if (sta) {
tdls_peer = test_sta_flag(sta,
WLAN_STA_TDLS_PEER);
tdls_auth = test_sta_flag(sta,
WLAN_STA_TDLS_PEER_AUTH);
}

if (tdls_peer)
tdls_setup_frame =
ethertype == ETH_P_TDLS &&
skb->len > 14 &&
skb->data[14] == WLAN_TDLS_SNAP_RFTYPE;
}

/*
* TDLS link during setup - throw out frames to peer. We allow
* TDLS-setup frames to unauthorized peers for the special case
* of a link teardown after a TDLS sta is removed due to being
* unreachable.
*/
if (tdls_peer && !tdls_auth && !tdls_setup_frame) {
ret = -EINVAL;
goto free;
}
/* we already did checks when looking up the RA STA */
tdls_peer = test_sta_flag(sta, WLAN_STA_TDLS_PEER);

/* send direct packets to authorized TDLS peers */
if (tdls_peer && tdls_auth) {
if (tdls_peer) {
/* DA SA BSSID */
memcpy(hdr.addr1, skb->data, ETH_ALEN);
memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
memcpy(hdr.addr3, sdata->u.mgd.bssid, ETH_ALEN);
hdrlen = 24;
have_station = true;
authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
wme_sta = sta->sta.wme;
*sta_out = sta;
} else if (sdata->u.mgd.use_4addr &&
cpu_to_be16(ethertype) != sdata->control_port_protocol) {
fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS |
Expand Down Expand Up @@ -2063,30 +2114,16 @@ static struct sk_buff *ieee80211_build_hdr(struct ieee80211_sub_if_data *sdata,
goto free;
}

/*
* There's no need to try to look up the destination station
* if it is a multicast address. In mesh, there's no need to
* look up the station at all as it always must be QoS capable
* and mesh mode checks authorization later.
*/
multicast = is_multicast_ether_addr(hdr.addr1);
if (multicast) {
*sta_out = ERR_PTR(-ENOENT);
} else if (!have_station && !ieee80211_vif_is_mesh(&sdata->vif)) {
if (sdata->control_port_protocol == skb->protocol)
sta = sta_info_get_bss(sdata, hdr.addr1);
else
sta = sta_info_get(sdata, hdr.addr1);
if (sta) {
authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
wme_sta = sta->sta.wme;
}
*sta_out = sta ?: ERR_PTR(-ENOENT);
}

/* For mesh, the use of the QoS header is mandatory */
if (ieee80211_vif_is_mesh(&sdata->vif))
/* sta is always NULL for mesh */
if (sta) {
authorized = test_sta_flag(sta, WLAN_STA_AUTHORIZED);
wme_sta = sta->sta.wme;
} else if (ieee80211_vif_is_mesh(&sdata->vif)) {
/* For mesh, the use of the QoS header is mandatory */
wme_sta = true;
}

/* receiver does QoS (which also means we do) use it */
if (wme_sta) {
Expand Down Expand Up @@ -2259,7 +2296,7 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
u32 info_flags)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
struct sta_info *sta = NULL;
struct sta_info *sta;

if (unlikely(skb->len < ETH_HLEN)) {
kfree_skb(skb);
Expand All @@ -2268,7 +2305,12 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,

rcu_read_lock();

skb = ieee80211_build_hdr(sdata, skb, info_flags, &sta);
if (ieee80211_lookup_ra_sta(sdata, skb, &sta)) {
kfree_skb(skb);
goto out;
}

skb = ieee80211_build_hdr(sdata, skb, info_flags, sta);
if (IS_ERR(skb))
goto out;

Expand Down Expand Up @@ -2304,11 +2346,17 @@ ieee80211_build_data_template(struct ieee80211_sub_if_data *sdata,
.local = sdata->local,
.sdata = sdata,
};
struct sta_info *sta_ignore;
struct sta_info *sta;

rcu_read_lock();

skb = ieee80211_build_hdr(sdata, skb, info_flags, &sta_ignore);
if (ieee80211_lookup_ra_sta(sdata, skb, &sta)) {
kfree_skb(skb);
skb = ERR_PTR(-EINVAL);
goto out;
}

skb = ieee80211_build_hdr(sdata, skb, info_flags, sta);
if (IS_ERR(skb))
goto out;

Expand Down

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