mac80211: What is get_sequence_counter?

mac80211: What is get_sequence_counter?

[Michael Buesch]

What is the get_sequence_counter callback for?

	/* For devices that have internal sequence counters, allow 802.11
	 * code to access the current value of a counter */
	int (*get_sequence_counter)(struct ieee80211_hw *hw,
				    u8* addr, u8 keyidx, u8 txrx,
				    u32* iv32, u16* iv16);

It doesn't seem to be used in current mac80211 code.
It seems that this is to fetch the current initial values.
Is that correct?
Who is supposed to use this callback? If it's unused, let's remove
it please. The documentation for it sucks anyway. :)

-- 
Greetings Michael.

Re: mac80211: What is get_sequence_counter?

[Johannes Berg]

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On Fri, 2007-10-05 at 15:56 +0200, Michael Buesch wrote:
> What is the get_sequence_counter callback for?
> 
> 	/* For devices that have internal sequence counters, allow 802.11
> 	 * code to access the current value of a counter */
> 	int (*get_sequence_counter)(struct ieee80211_hw *hw,
> 				    u8* addr, u8 keyidx, u8 txrx,
> 				    u32* iv32, u16* iv16);
> 
> It doesn't seem to be used in current mac80211 code.
> It seems that this is to fetch the current initial values.
> Is that correct?
> Who is supposed to use this callback? If it's unused, let's remove
> it please. The documentation for it sucks anyway. :)

No, it's actually used in a patch I'm about to post:
http://johannes.sipsolutions.net/patches/kernel/all/2007-09-28-22%3a38/017-mac80211-key-seq-nl80211.patch

Mind you, it could be renamed and described better; it's used for
getting the current sequence number of a hardware TKIP implementation.

johannes

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Re: mac80211: What is get_sequence_counter?

[Michael Buesch]

On Friday 05 October 2007 16:03:24 Johannes Berg wrote:
> On Fri, 2007-10-05 at 15:56 +0200, Michael Buesch wrote:
> > What is the get_sequence_counter callback for?
> > 
> > 	/* For devices that have internal sequence counters, allow 802.11
> > 	 * code to access the current value of a counter */
> > 	int (*get_sequence_counter)(struct ieee80211_hw *hw,
> > 				    u8* addr, u8 keyidx, u8 txrx,
> > 				    u32* iv32, u16* iv16);
> > 
> > It doesn't seem to be used in current mac80211 code.
> > It seems that this is to fetch the current initial values.
> > Is that correct?
> > Who is supposed to use this callback? If it's unused, let's remove
> > it please. The documentation for it sucks anyway. :)
> 
> No, it's actually used in a patch I'm about to post:
> http://johannes.sipsolutions.net/patches/kernel/all/2007-09-28-22%3a38/017-mac80211-key-seq-nl80211.patch
> 
> Mind you, it could be renamed and described better; it's used for
> getting the current sequence number of a hardware TKIP implementation.

Ah, ok. It sounded to me like it's supposed to fetch the
seq_ctrl counter (data header), if the device does frame sequence
counting in hw.
Can you please rename that to something like
get_tkip_ivs() or
get_tkip_counters()
or something like that?

-- 
Greetings Michael.

Re: mac80211: What is get_sequence_counter?

[Johannes Berg]

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On Fri, 2007-10-05 at 16:06 +0200, Michael Buesch wrote:

> Ah, ok. It sounded to me like it's supposed to fetch the
> seq_ctrl counter (data header), if the device does frame sequence
> counting in hw.

Ah ok, yeah, it's badly named.

> Can you please rename that to something like
> get_tkip_ivs() or
> get_tkip_counters()
> or something like that?

Sure, I'll add that to the patch that uses it.

johannes

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Re: mac80211: What is get_sequence_counter?

[Johannes Berg]

How's this? (scroll all the way down)

I changed the prototype too to pass the hw_key_idx instead of the key.

Subject: mac80211: implement the new cfg80211 get_key hook

This implements get_key() to replace all the prism2 ioctl
functionality.

Not-signed-off-by: Johannes Berg <johannes@sipsolutions.net>

---
 include/net/mac80211.h |   11 ++----
 net/mac80211/cfg.c     |   85 ++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 89 insertions(+), 7 deletions(-)

--- wireless-dev.orig/net/mac80211/cfg.c	2007-10-08 12:24:10.595111702 +0200
+++ wireless-dev/net/mac80211/cfg.c	2007-10-08 13:29:54.865107447 +0200
@@ -1,7 +1,7 @@
 /*
  * mac80211 configuration hooks for cfg80211
  *
- * Copyright 2006	Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2006, 2007	Johannes Berg <johannes@sipsolutions.net>
  *
  * This file is GPLv2 as found in COPYING.
  */
@@ -174,6 +174,88 @@ static int ieee80211_del_key(struct wiph
 	return 0;
 }
 
+static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev,
+			     u8 key_idx, u8 *mac_addr, void *cookie,
+			     void (*callback)(void *cookie,
+					      struct key_params *params))
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct sta_info *sta = NULL;
+	u8 seq[6] = {0};
+	struct key_params params;
+	struct ieee80211_key *key;
+	u32 iv32;
+	u16 iv16;
+	int err = -ENOENT;
+
+	if (mac_addr) {
+		sta = sta_info_get(sdata->local, mac_addr);
+		if (!sta)
+			goto out;
+
+		key = sta->key;
+	} else
+		key = sdata->keys[key_idx];
+
+	if (!key)
+		goto out;
+
+	memset(&params, 0, sizeof(params));
+
+	switch (key->conf.alg) {
+	case ALG_TKIP:
+		params.cipher = WLAN_CIPHER_SUITE_TKIP;
+
+		iv32 = key->u.tkip.iv32;
+		iv16 = key->u.tkip.iv16;
+
+		if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
+		    sdata->local->ops->get_tkip_seq)
+			sdata->local->ops->get_tkip_seq(
+				local_to_hw(sdata->local),
+				key->conf.hw_key_idx,
+				&iv32, &iv16);
+
+		seq[0] = iv16 & 0xff;
+		seq[1] = (iv16 >> 8) & 0xff;
+		seq[2] = iv32 & 0xff;
+		seq[3] = (iv32 >> 8) & 0xff;
+		seq[4] = (iv32 >> 16) & 0xff;
+		seq[5] = (iv32 >> 24) & 0xff;
+		params.seq = seq;
+		params.seq_len = 6;
+		break;
+	case ALG_CCMP:
+		params.cipher = WLAN_CIPHER_SUITE_CCMP;
+		seq[0] = key->u.ccmp.tx_pn[5];
+		seq[1] = key->u.ccmp.tx_pn[4];
+		seq[2] = key->u.ccmp.tx_pn[3];
+		seq[3] = key->u.ccmp.tx_pn[2];
+		seq[4] = key->u.ccmp.tx_pn[1];
+		seq[5] = key->u.ccmp.tx_pn[0];
+		params.seq = seq;
+		params.seq_len = 6;
+		break;
+	case ALG_WEP:
+		if (key->conf.keylen == 5)
+			params.cipher = WLAN_CIPHER_SUITE_WEP40;
+		else
+			params.cipher = WLAN_CIPHER_SUITE_WEP104;
+		break;
+	}
+
+	params.key = key->conf.key;
+	params.key_len = key->conf.keylen;
+
+	callback(cookie, &params);
+	err = 0;
+
+ out:
+	if (sta)
+		sta_info_put(sta);
+	return err;
+}
+
 static int ieee80211_config_default_key(struct wiphy *wiphy,
 					struct net_device *dev,
 					u8 key_idx)
@@ -192,5 +274,6 @@ struct cfg80211_ops mac80211_config_ops 
 	.change_virtual_intf = ieee80211_change_iface,
 	.add_key = ieee80211_add_key,
 	.del_key = ieee80211_del_key,
+	.get_key = ieee80211_get_key,
 	.set_default_key = ieee80211_config_default_key,
 };
--- wireless-dev.orig/include/net/mac80211.h	2007-10-08 13:19:18.845107447 +0200
+++ wireless-dev/include/net/mac80211.h	2007-10-08 13:25:55.595107447 +0200
@@ -957,9 +957,9 @@ enum ieee80211_erp_change_flags {
  *	response or association responses this updates the state of privacy_invoked
  *	returns 0 for success or an error number.
  *
- * @get_sequence_counter: For devices that have internal sequence counters this
- *	callback allows mac80211 to access the current value of a counter.
- *	This callback seems not well-defined, tell us if you need it.
+ * @get_tkip_seq: If your device implements TKIP encryption in hardware this
+ *	callback should be provided to read the TKIP transmit IVs (both IV32
+ *	and IV16) for the given key from hardware.
  *
  * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
  *
@@ -1037,9 +1037,8 @@ struct ieee80211_ops {
 			 struct ieee80211_low_level_stats *stats);
 	int (*set_privacy_invoked)(struct ieee80211_hw *hw,
 				   int privacy_invoked);
-	int (*get_sequence_counter)(struct ieee80211_hw *hw,
-				    u8* addr, u8 keyidx, u8 txrx,
-				    u32* iv32, u16* iv16);
+	void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
+			     u32 *iv32, u16 *iv16);
 	int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
 	int (*set_frag_threshold)(struct ieee80211_hw *hw, u32 value);
 	int (*set_retry_limit)(struct ieee80211_hw *hw,

Re: mac80211: What is get_sequence_counter?

[Michael Buesch]

On Tuesday 09 October 2007 11:12:37 Johannes Berg wrote:
> How's this? (scroll all the way down)
> 
> I changed the prototype too to pass the hw_key_idx instead of the key.
> 
> Subject: mac80211: implement the new cfg80211 get_key hook
> 
> This implements get_key() to replace all the prism2 ioctl
> functionality.

Great, I like it.

> Not-signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> 
> ---
>  include/net/mac80211.h |   11 ++----
>  net/mac80211/cfg.c     |   85 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 89 insertions(+), 7 deletions(-)
> 
> --- wireless-dev.orig/net/mac80211/cfg.c	2007-10-08 12:24:10.595111702 +0200
> +++ wireless-dev/net/mac80211/cfg.c	2007-10-08 13:29:54.865107447 +0200
> @@ -1,7 +1,7 @@
>  /*
>   * mac80211 configuration hooks for cfg80211
>   *
> - * Copyright 2006	Johannes Berg <johannes@sipsolutions.net>
> + * Copyright 2006, 2007	Johannes Berg <johannes@sipsolutions.net>
>   *
>   * This file is GPLv2 as found in COPYING.
>   */
> @@ -174,6 +174,88 @@ static int ieee80211_del_key(struct wiph
>  	return 0;
>  }
>  
> +static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev,
> +			     u8 key_idx, u8 *mac_addr, void *cookie,
> +			     void (*callback)(void *cookie,
> +					      struct key_params *params))
> +{
> +	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
> +	struct sta_info *sta = NULL;
> +	u8 seq[6] = {0};
> +	struct key_params params;
> +	struct ieee80211_key *key;
> +	u32 iv32;
> +	u16 iv16;
> +	int err = -ENOENT;
> +
> +	if (mac_addr) {
> +		sta = sta_info_get(sdata->local, mac_addr);
> +		if (!sta)
> +			goto out;
> +
> +		key = sta->key;
> +	} else
> +		key = sdata->keys[key_idx];
> +
> +	if (!key)
> +		goto out;
> +
> +	memset(&params, 0, sizeof(params));
> +
> +	switch (key->conf.alg) {
> +	case ALG_TKIP:
> +		params.cipher = WLAN_CIPHER_SUITE_TKIP;
> +
> +		iv32 = key->u.tkip.iv32;
> +		iv16 = key->u.tkip.iv16;
> +
> +		if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE &&
> +		    sdata->local->ops->get_tkip_seq)
> +			sdata->local->ops->get_tkip_seq(
> +				local_to_hw(sdata->local),
> +				key->conf.hw_key_idx,
> +				&iv32, &iv16);
> +
> +		seq[0] = iv16 & 0xff;
> +		seq[1] = (iv16 >> 8) & 0xff;
> +		seq[2] = iv32 & 0xff;
> +		seq[3] = (iv32 >> 8) & 0xff;
> +		seq[4] = (iv32 >> 16) & 0xff;
> +		seq[5] = (iv32 >> 24) & 0xff;
> +		params.seq = seq;
> +		params.seq_len = 6;
> +		break;
> +	case ALG_CCMP:
> +		params.cipher = WLAN_CIPHER_SUITE_CCMP;
> +		seq[0] = key->u.ccmp.tx_pn[5];
> +		seq[1] = key->u.ccmp.tx_pn[4];
> +		seq[2] = key->u.ccmp.tx_pn[3];
> +		seq[3] = key->u.ccmp.tx_pn[2];
> +		seq[4] = key->u.ccmp.tx_pn[1];
> +		seq[5] = key->u.ccmp.tx_pn[0];
> +		params.seq = seq;
> +		params.seq_len = 6;
> +		break;
> +	case ALG_WEP:
> +		if (key->conf.keylen == 5)
> +			params.cipher = WLAN_CIPHER_SUITE_WEP40;
> +		else
> +			params.cipher = WLAN_CIPHER_SUITE_WEP104;
> +		break;
> +	}
> +
> +	params.key = key->conf.key;
> +	params.key_len = key->conf.keylen;
> +
> +	callback(cookie, &params);
> +	err = 0;
> +
> + out:
> +	if (sta)
> +		sta_info_put(sta);
> +	return err;
> +}
> +
>  static int ieee80211_config_default_key(struct wiphy *wiphy,
>  					struct net_device *dev,
>  					u8 key_idx)
> @@ -192,5 +274,6 @@ struct cfg80211_ops mac80211_config_ops 
>  	.change_virtual_intf = ieee80211_change_iface,
>  	.add_key = ieee80211_add_key,
>  	.del_key = ieee80211_del_key,
> +	.get_key = ieee80211_get_key,
>  	.set_default_key = ieee80211_config_default_key,
>  };
> --- wireless-dev.orig/include/net/mac80211.h	2007-10-08 13:19:18.845107447 +0200
> +++ wireless-dev/include/net/mac80211.h	2007-10-08 13:25:55.595107447 +0200
> @@ -957,9 +957,9 @@ enum ieee80211_erp_change_flags {
>   *	response or association responses this updates the state of privacy_invoked
>   *	returns 0 for success or an error number.
>   *
> - * @get_sequence_counter: For devices that have internal sequence counters this
> - *	callback allows mac80211 to access the current value of a counter.
> - *	This callback seems not well-defined, tell us if you need it.
> + * @get_tkip_seq: If your device implements TKIP encryption in hardware this
> + *	callback should be provided to read the TKIP transmit IVs (both IV32
> + *	and IV16) for the given key from hardware.
>   *
>   * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
>   *
> @@ -1037,9 +1037,8 @@ struct ieee80211_ops {
>  			 struct ieee80211_low_level_stats *stats);
>  	int (*set_privacy_invoked)(struct ieee80211_hw *hw,
>  				   int privacy_invoked);
> -	int (*get_sequence_counter)(struct ieee80211_hw *hw,
> -				    u8* addr, u8 keyidx, u8 txrx,
> -				    u32* iv32, u16* iv16);
> +	void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
> +			     u32 *iv32, u16 *iv16);
>  	int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
>  	int (*set_frag_threshold)(struct ieee80211_hw *hw, u32 value);
>  	int (*set_retry_limit)(struct ieee80211_hw *hw,
> 
> 
> 
> 



-- 
Greetings Michael.