Mac80211 drivers can now pass paged SKBs to mac80211 via
ieee80211_rx{_irqsafe}. The implementation currently use
skb_linearize() in a few places i.e. management frame
handling, software decryption, defragmentation and A-MSDU
process. We will optimize them one by one later.
Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx>
Cc: Kalle Valo <kalle.valo@xxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
V2: add comments for paged skb support
fix pskb_may_pull size for ieee80211 and mesh header
use RX_DROP_UNUSABLE instead of RX_DROP_MONITOR
include/net/mac80211.h | 5 ++++-
net/mac80211/rx.c | 36 ++++++++++++++++++++++++++++++++----
net/wireless/util.c | 8 +++++++-
3 files changed, 43 insertions(+), 6 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 1a8f50a..ecaae10 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1822,7 +1822,10 @@ void ieee80211_restart_hw(struct ieee80211_hw *hw);
* ieee80211_rx - receive frame
*
* Use this function to hand received frames to mac80211. The receive
- * buffer in @skb must start with an IEEE 802.11 header.
+ * buffer in @skb must start with an IEEE 802.11 header. In case of a
+ * paged @skb is used, the driver is recommended to put the ieee80211
+ * header of the frame on the linear part of the @skb to avoid memory
+ * allocation and/or memcpy by the stack.
*
* This function may not be called in IRQ context. Calls to this function
* for a single hardware must be synchronized against each other. Calls to
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 1da57c8..11ed5aa 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -38,7 +38,7 @@ static struct sk_buff *remove_monitor_info(struct ieee80211_local *local,
{
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS) {
if (likely(skb->len > FCS_LEN))
- skb_trim(skb, skb->len - FCS_LEN);
+ __pskb_trim(skb, skb->len - FCS_LEN);
else {
/* driver bug */
WARN_ON(1);
@@ -227,6 +227,12 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
present_fcs_len = FCS_LEN;
+ /* make sure hdr->frame_control is on the linear part */
+ if (!pskb_may_pull(origskb, 2)) {
+ dev_kfree_skb(origskb);
+ return NULL;
+ }
+
if (!local->monitors) {
if (should_drop_frame(origskb, present_fcs_len)) {
dev_kfree_skb(origskb);
@@ -931,6 +937,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
return RX_DROP_MONITOR;
}
+ if (skb_linearize(rx->skb))
+ return RX_DROP_UNUSABLE;
+
/* Check for weak IVs if possible */
if (rx->sta && rx->key->conf.alg == ALG_WEP &&
ieee80211_is_data(hdr->frame_control) &&
@@ -1231,6 +1240,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
}
I802_DEBUG_INC(rx->local->rx_handlers_fragments);
+ if (skb_linearize(rx->skb))
+ return RX_DROP_UNUSABLE;
+
seq = (sc & IEEE80211_SCTL_SEQ) >> 4;
if (frag == 0) {
@@ -1588,6 +1600,9 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
skb->dev = dev;
__skb_queue_head_init(&frame_list);
+ if (skb_linearize(skb))
+ return RX_DROP_UNUSABLE;
+
ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
rx->sdata->vif.type,
rx->local->hw.extra_tx_headroom);
@@ -2357,29 +2372,42 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
struct ieee80211_hdr *hdr;
+ __le16 fc;
struct ieee80211_rx_data rx;
int prepares;
struct ieee80211_sub_if_data *prev = NULL;
struct sk_buff *skb_new;
struct sta_info *sta, *tmp;
bool found_sta = false;
+ int err = 0;
- hdr = (struct ieee80211_hdr *)skb->data;
+ fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
memset(&rx, 0, sizeof(rx));
rx.skb = skb;
rx.local = local;
- if (ieee80211_is_data(hdr->frame_control) || ieee80211_is_mgmt(hdr->frame_control))
+ if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))
local->dot11ReceivedFragmentCount++;
if (unlikely(test_bit(SCAN_HW_SCANNING, &local->scanning) ||
test_bit(SCAN_OFF_CHANNEL, &local->scanning)))
rx.flags |= IEEE80211_RX_IN_SCAN;
+ if (ieee80211_is_mgmt(fc))
+ err = skb_linearize(skb);
+ else
+ err = !pskb_may_pull(skb, ieee80211_hdrlen(fc));
+
+ if (err) {
+ dev_kfree_skb(skb);
+ return;
+ }
+
+ hdr = (struct ieee80211_hdr *)skb->data;
ieee80211_parse_qos(&rx);
ieee80211_verify_alignment(&rx);
- if (ieee80211_is_data(hdr->frame_control)) {
+ if (ieee80211_is_data(fc)) {
for_each_sta_info(local, hdr->addr2, sta, tmp) {
rx.sta = sta;
found_sta = true;
diff --git a/net/wireless/util.c b/net/wireless/util.c
index be2ab8c..63c60b9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -330,6 +330,9 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
if (iftype == NL80211_IFTYPE_MESH_POINT) {
struct ieee80211s_hdr *meshdr =
(struct ieee80211s_hdr *) (skb->data + hdrlen);
+ /* make sure meshdr->flags is on the linear part */
+ if (!pskb_may_pull(skb, hdrlen + 1))
+ return -1;
hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
memcpy(dst, meshdr->eaddr1, ETH_ALEN);
@@ -346,6 +349,9 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
if (iftype == NL80211_IFTYPE_MESH_POINT) {
struct ieee80211s_hdr *meshdr =
(struct ieee80211s_hdr *) (skb->data + hdrlen);
+ /* make sure meshdr->flags is on the linear part */
+ if (!pskb_may_pull(skb, hdrlen + 1))
+ return -1;
hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
if (meshdr->flags & MESH_FLAGS_AE_A4)
memcpy(src, meshdr->eaddr1, ETH_ALEN);
@@ -357,7 +363,7 @@ int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
break;
}
- if (unlikely(skb->len - hdrlen < 8))
+ if (!pskb_may_pull(skb, hdrlen + 8))
return -1;
payload = skb->data + hdrlen;
--
1.6.3.3
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