Re: [PATCH v3] d80211: Add software sequence support

[Ivo van Doorn <ivdoorn@gmail.com>]

On Saturday 10 March 2007 20:32, Michael Buesch wrote:
> On Saturday 10 March 2007 20:21, Ivo van Doorn wrote:
> > Most hardware can keep track of sequence numbers themselves,
> > unfortunately *most* doesn't cover all devices. ;)
> > This patch will keep track of the (per-bss) sequence number
> > if the flag IEEE80211_HW_SOFTWARE_SEQUENCE has been set.
> 
> The question has been asked (by Jouni), but I didn't see
> a good answer (maybe I missed it).
> Why is this a flag at all? The sequence counter is such a
> trivial thing that having an extra conditional is just _more_
> overhead. Why not simply calculate the seq all the time and
> let hardware override it, if it has the capability to do so?
> Calculation of the seq is cheap. No need to bloat code.

It would also safe me a patch for rt2400pci and rt2500pci as well. ;)

Well if nobody objects against setting the sequence number
always, then below patch would be sufficient. :)

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
 
---

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 577dbe3..05a0929 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -54,6 +54,20 @@ static u8 * ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len);
 static int ieee80211_mgmt_start_xmit(struct sk_buff *skb,
 				     struct net_device *dev);
 
+static void ieee80211_include_sequence(struct ieee80211_sub_if_data *sdata,
+				       struct ieee80211_hdr *hdr)
+{
+	/*
+	 * Set the sequence number for this frame.
+	 */
+	hdr->seq_ctrl = cpu_to_le16(sdata->sequence & IEEE80211_SCTL_SEQ);
+
+	/*
+	 * Increase the sequence number.
+	 */
+	sdata->sequence = (sdata->sequence + 0x10) & IEEE80211_SCTL_SEQ;
+}
+
 struct ieee80211_key_conf *
 ieee80211_key_data2conf(struct ieee80211_local *local,
 			const struct ieee80211_key *data)
@@ -445,6 +459,7 @@ ieee80211_tx_h_fragment(struct ieee80211_txrx_data *tx)
 	size_t hdrlen, per_fragm, num_fragm, payload_len, left;
 	struct sk_buff **frags, *first, *frag;
 	int i;
+	u16 seq;
 	u8 *pos;
 	int frag_threshold = tx->local->fragmentation_threshold;
 
@@ -463,6 +478,7 @@ ieee80211_tx_h_fragment(struct ieee80211_txrx_data *tx)
 		goto fail;
 
 	hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_MOREFRAGS);
+	seq = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_SEQ;
 	pos = first->data + hdrlen + per_fragm;
 	left = payload_len - per_fragm;
 	for (i = 0; i < num_fragm - 1; i++) {
@@ -490,7 +506,7 @@ ieee80211_tx_h_fragment(struct ieee80211_txrx_data *tx)
 		memcpy(fhdr, first->data, hdrlen);
 		if (i == num_fragm - 2)
 			fhdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_MOREFRAGS);
-		fhdr->seq_ctrl = cpu_to_le16(i + 1);
+		fhdr->seq_ctrl = cpu_to_le16(seq + ((i + 1) & IEEE80211_SCTL_FRAG));
 		copylen = left > per_fragm ? per_fragm : left;
 		memcpy(skb_put(frag, copylen), pos, copylen);
 
@@ -900,6 +916,16 @@ ieee80211_tx_h_check_assoc(struct ieee80211_txrx_data *tx)
 	return TXRX_CONTINUE;
 }
 
+static ieee80211_txrx_result
+ieee80211_tx_h_sequence(struct ieee80211_txrx_data *tx)
+{
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)tx->skb->data;
+
+	if (ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control)) >= 24)
+		ieee80211_include_sequence(tx->sdata, hdr);
+
+	return TXRX_CONTINUE;
+}
 
 /* This function is called whenever the AP is about to exceed the maximum limit
  * of buffered frames for power saving STAs. This situation should not really
@@ -1770,6 +1796,8 @@ struct sk_buff * ieee80211_beacon_get(struct ieee80211_hw *hw, int if_id,
 	skb_reserve(skb, local->hw.extra_tx_headroom);
 	memcpy(skb_put(skb, bh_len), b_head, bh_len);
 
+	ieee80211_include_sequence(sdata, (struct ieee80211_hdr *)skb->data);
+
 	ieee80211_beacon_add_tim(local, ap, skb);
 
 	if (b_tail) {
@@ -4381,6 +4409,7 @@ static ieee80211_rx_handler ieee80211_rx_handlers[] =
 static ieee80211_tx_handler ieee80211_tx_handlers[] =
 {
 	ieee80211_tx_h_check_assoc,
+	ieee80211_tx_h_sequence,
 	ieee80211_tx_h_ps_buf,
 	ieee80211_tx_h_select_key,
 	ieee80211_tx_h_michael_mic_add,
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9df8ef0..4b7c427 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -317,6 +317,8 @@ struct ieee80211_sub_if_data {
 	int ieee802_1x; /* IEEE 802.1X PAE - drop packet to/from unauthorized
 			 * port */
 
+	u16 sequence;
+
 	/* Fragment table for host-based reassembly */
 	struct ieee80211_fragment_entry	fragments[IEEE80211_FRAGMENT_MAX];
 	unsigned int fragment_next;