wireless: add ieee80211_amsdu_to_8023s

Move the A-MSDU handling code from mac80211 to cfg80211 so that more
drivers can use it. The new created function ieee80211_amsdu_to_8023s
converts an A-MSDU frame to a list of 802.3 frames.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 97 insertions, 2 deletions

diff --git a/net/wireless/util.c b/net/wireless/util.c
index a3c841a..23557c1 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -285,7 +285,7 @@ static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 	}
 }
 
-int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
+int ieee80211_data_to_8023(struct sk_buff *skb, const u8 *addr,
 			   enum nl80211_iftype iftype)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
@@ -383,7 +383,7 @@ int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
 }
 EXPORT_SYMBOL(ieee80211_data_to_8023);
 
-int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
+int ieee80211_data_from_8023(struct sk_buff *skb, const u8 *addr,
 			     enum nl80211_iftype iftype, u8 *bssid, bool qos)
 {
 	struct ieee80211_hdr hdr;
@@ -497,6 +497,101 @@ int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
 }
 EXPORT_SYMBOL(ieee80211_data_from_8023);
 
+
+void ieee80211_amsdu_to_8023s(struct sk_buff *skb, struct sk_buff_head *list,
+			      const u8 *addr, enum nl80211_iftype iftype,
+			      const unsigned int extra_headroom)
+{
+	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)
+		goto out;
+
+	/* skip the wrapping header */
+	eth = (struct ethhdr *) skb_pull(skb, sizeof(struct ethhdr));
+	if (!eth)
+		goto out;
+
+	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 {
+			unsigned int hlen = ALIGN(extra_headroom, 4);
+			/*
+			 * Allocate and reserve two bytes more for payload
+			 * alignment since sizeof(struct ethhdr) is 14.
+			 */
+			frame = dev_alloc_skb(hlen + subframe_len + 2);
+			if (!frame)
+				goto purge;
+
+			skb_reserve(frame, hlen + 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;
+
+ purge:
+	__skb_queue_purge(list);
+ out:
+	dev_kfree_skb(skb);
+}
+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)
 {