[RFC 1/2] wireless: add ieee80211_asmdu_to_8023s

Zhu Yi
2009-11-26T06:00:16Z

Move the A-MSDU handling code from mac80211 to cfg80211 so that more
drivers can use it. The new created function ieee80211_asmdu_to_8023s
converts an A-MSDU frame to a list of 802.3 frames.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
---
include/net/cfg80211.h | 12 +++++
net/mac80211/rx.c | 107 ++++++++++-------------------------------------
net/wireless/util.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 140 insertions(+), 84 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0884b9a..ad31b55 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1593,6 +1593,18 @@ int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
enum nl80211_iftype iftype, u8 *bssid, bool qos);

/**
+ * ieee80211_asmdu_to_8023s - decode an IEEE 802.11n A-MSDU frame
+ *
+ * @skb: The input IEEE 802.11n A-MSDU frame.
+ * @list: The output list of 802.3 frames. It must be allocated and
+ * initialized by by the caller.
+ * @addr: The device MAC address.
+ * @iftype: The device interface type.
+ */
+int ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
+ u8 *addr, enum nl80211_iftype iftype);
+
+/**
* cfg80211_classify8021d - determine the 802.1p/1d tag for a data frame
* @skb: the data frame
*/
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 57b8a0a..34ab25d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1556,16 +1556,11 @@ static ieee80211_rx_result debug_noinline
ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
{
struct net_device *dev = rx->sdata->dev;
- struct ieee80211_local *local = rx->local;
- u16 ethertype;
- u8 *payload;
- struct sk_buff *skb = rx->skb, *frame = NULL;
+ struct sk_buff *skb = rx->skb;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
__le16 fc = hdr->frame_control;
- const struct ethhdr *eth;
- int remaining, err;
- u8 dst[ETH_ALEN];
- u8 src[ETH_ALEN];
+ int err;
+ struct sk_buff_head frame_list;

if (unlikely(!ieee80211_is_data(fc)))
return RX_CONTINUE;
@@ -1576,92 +1571,36 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx)
if (!(rx->flags & IEEE80211_RX_AMSDU))
return RX_CONTINUE;

- err = __ieee80211_data_to_8023(rx);
- if (unlikely(err))
+ if (ieee80211_has_a4(hdr->frame_control) &&
+ rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
+ !rx->sdata->u.vlan.sta)
return RX_DROP_UNUSABLE;

- skb->dev = dev;
-
- dev->stats.rx_packets++;
- dev->stats.rx_bytes += skb->len;
-
- /* skip the wrapping header */
- eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
- if (!eth)
+ if (is_multicast_ether_addr(hdr->addr1) &&
+ ((rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
+ rx->sdata->u.vlan.sta) ||
+ (rx->sdata->vif.type == NL80211_IFTYPE_STATION &&
+ rx->sdata->u.mgd.use_4addr)))
return RX_DROP_UNUSABLE;

- while (skb != frame) {
- u8 padding;
- __be16 len = eth->h_proto;
- unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
-
- remaining = skb->len;
- memcpy(dst, eth->h_dest, ETH_ALEN);
- memcpy(src, eth->h_source, ETH_ALEN);
-
- padding = ((4 - subframe_len) & 0x3);
- /* the last MSDU has no padding */
- if (subframe_len > remaining)
- return RX_DROP_UNUSABLE;
-
- skb_pull(skb, sizeof(struct ethhdr));
- /* if last subframe reuse skb */
- if (remaining <= subframe_len + padding)
- frame = skb;
- else {
- /*
- * Allocate and reserve two bytes more for payload
- * alignment since sizeof(struct ethhdr) is 14.
- */
- frame = dev_alloc_skb(
- ALIGN(local->hw.extra_tx_headroom, 4) +
- subframe_len + 2);
-
- if (frame == NULL)
- return RX_DROP_UNUSABLE;
+ skb->dev = dev;
+ skb_queue_head_init(&frame_list);

- skb_reserve(frame,
- ALIGN(local->hw.extra_tx_headroom, 4) +
- sizeof(struct ethhdr) + 2);
- memcpy(skb_put(frame, ntohs(len)), skb->data,
- ntohs(len));
+ err = ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr,
+ rx->sdata->vif.type);
+ if (err)
+ return RX_DROP_UNUSABLE;

- eth = (struct ethhdr *) skb_pull(skb, ntohs(len) +
- padding);
- if (!eth) {
- dev_kfree_skb(frame);
- return RX_DROP_UNUSABLE;
- }
- }
+ dev->stats.rx_packets++;
+ dev->stats.rx_bytes += skb->len;

- skb_reset_network_header(frame);
- frame->dev = dev;
- frame->priority = skb->priority;
- rx->skb = frame;
-
- payload = frame->data;
- ethertype = (payload[6] << 8) | payload[7];
-
- if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
- ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
- compare_ether_addr(payload,
- bridge_tunnel_header) == 0)) {
- /* remove RFC1042 or Bridge-Tunnel
- * encapsulation and replace EtherType */
- skb_pull(frame, 6);
- memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
- memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
- } else {
- memcpy(skb_push(frame, sizeof(__be16)),
- &len, sizeof(__be16));
- memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
- memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
- }
+ while (!skb_queue_empty(&frame_list)) {
+ rx->skb = skb_dequeue(&frame_list);

if (!ieee80211_frame_allowed(rx, fc)) {
- if (skb == frame) /* last frame */
+ if (skb == rx->skb) /* last frame */
return RX_DROP_UNUSABLE;
- dev_kfree_skb(frame);
+ dev_kfree_skb(rx->skb);
continue;
}

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 59361fd..8ed98d7 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -497,6 +497,111 @@ int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
}
EXPORT_SYMBOL(ieee80211_data_from_8023);

+/**
+ * ieee80211_asmdu_to_8023s - decode an IEEE 802.11n A-MSDU frame
+ *
+ * Decode an IEEE 802.11n A-MSDU frame and convert it to a list of
+ * 802.3 frames. This function returns 0 on succeess. In this case,
+ * we optimize the code to reuse the @skb to hold the last 802.3
+ * frame in the @list.
+ *
+ * @skb: The input IEEE 802.11n A-MSDU frame.
+ * @list: The output list of 802.3 frames. It must be allocated and
+ * initialized by by the caller.
+ * @addr: The device MAC address.
+ * @iftype: The device interface type.
+ */
+int ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
+ u8 *addr, enum nl80211_iftype iftype)
+{
+ struct sk_buff *frame = NULL;
+ u16 ethertype;
+ u8 *payload;
+ const struct ethhdr *eth;
+ int remaining, err;
+ u8 dst[ETH_ALEN], src[ETH_ALEN];
+
+ err = ieee80211_data_to_8023(skb, addr, iftype);
+ if (err)
+ return err;
+
+ /* skip the wrapping header */
+ eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
+ if (!eth)
+ return -1;
+
+ while (skb != frame) {
+ u8 padding;
+ __be16 len = eth->h_proto;
+ unsigned int subframe_len = sizeof(struct ethhdr) + ntohs(len);
+
+ remaining = skb->len;
+ memcpy(dst, eth->h_dest, ETH_ALEN);
+ memcpy(src, eth->h_source, ETH_ALEN);
+
+ padding = (4 - subframe_len) & 0x3;
+ /* the last MSDU has no padding */
+ if (subframe_len > remaining)
+ goto purge;
+
+ skb_pull(skb, sizeof(struct ethhdr));
+ /* reuse skb for the last subframe */
+ if (remaining <= subframe_len + padding)
+ frame = skb;
+ else {
+ /*
+ * Allocate and reserve two bytes more for payload
+ * alignment since sizeof(struct ethhdr) is 14.
+ */
+ frame = dev_alloc_skb(subframe_len + 2);
+ if (!frame)
+ goto purge;
+
+ skb_reserve(frame, sizeof(struct ethhdr) + 2);
+ memcpy(skb_put(frame, ntohs(len)), skb->data,
+ ntohs(len));
+
+ eth = (struct ethhdr *)skb_pull(skb, ntohs(len) +
+ padding);
+ if (!eth) {
+ dev_kfree_skb(frame);
+ goto purge;
+ }
+ }
+
+ skb_reset_network_header(frame);
+ frame->dev = skb->dev;
+ frame->priority = skb->priority;
+
+ payload = frame->data;
+ ethertype = (payload[6] << 8) | payload[7];
+
+ if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
+ ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
+ compare_ether_addr(payload,
+ bridge_tunnel_header) == 0)) {
+ /* remove RFC1042 or Bridge-Tunnel
+ * encapsulation and replace EtherType */
+ skb_pull(frame, 6);
+ memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
+ memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
+ } else {
+ memcpy(skb_push(frame, sizeof(__be16)), &len,
+ sizeof(__be16));
+ memcpy(skb_push(frame, ETH_ALEN), src, ETH_ALEN);
+ memcpy(skb_push(frame, ETH_ALEN), dst, ETH_ALEN);
+ }
+ skb_queue_tail(list, frame);
+ }
+
+ return 0;
+
+ purge:
+ skb_queue_purge(list);
+ return -1;
+}
+EXPORT_SYMBOL(ieee80211_amsdu_to_8023s);
+
/* Given a data frame determine the 802.1p/1d tag to use. */
unsigned int cfg80211_classify8021d(struct sk_buff *skb)
{
--
1.6.0.4