diff mbox

staging: batman-adv: Use linux/etherdevice.h address helper functions

Message ID 1288778342-10056-1-git-send-email-tklauser@distanz.ch (mailing list archive)
State Not Applicable, archived
Headers

Commit Message

Tobias Klauser Nov. 3, 2010, 9:59 a.m. UTC 
  Replace custom ethernet address check functions by calls to the helpers
in linux/etherdevice.h

In one case where the address was tested for broadcast and multicast
address, the broadcast address check can be omitted as broadcast is also
a multicast address.

The patch is only compile-tested.

Cc: Marek Lindner <lindner_marek@yahoo.de>
Cc: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
---
 drivers/staging/batman-adv/main.c           |   12 +-----------
 drivers/staging/batman-adv/main.h           |    3 +--
 drivers/staging/batman-adv/routing.c        |   16 ++++++++--------
 drivers/staging/batman-adv/soft-interface.c |    2 +-
 drivers/staging/batman-adv/vis.c            |    4 ++--
 5 files changed, 13 insertions(+), 24 deletions(-)

Comments

Sven Eckelmann Nov. 3, 2010, 10:12 a.m. UTC | #1 
On Wednesday 03 November 2010 10:59:02 you wrote:
> Replace custom ethernet address check functions by calls to the helpers
> in linux/etherdevice.h

Have you proven that the addresses are always two bytes aligned in memory? 
Afaik this function needs it.

> In one case where the address was tested for broadcast and multicast
> address, the broadcast address check can be omitted as broadcast is also
> a multicast address.

We need to distinguish between these two types for different optimizations 
(research is currently done for multicast over mesh - but currently not part 
of batman-adv).


Best regards,
	Sven
Tobias Klauser Nov. 3, 2010, 10:25 a.m. UTC | #2 
On 2010-11-03 at 11:12:12 +0100, Sven Eckelmann <sven.eckelmann@gmx.de> wrote:
> On Wednesday 03 November 2010 10:59:02 you wrote:
> > Replace custom ethernet address check functions by calls to the helpers
> > in linux/etherdevice.h
> 
> Have you proven that the addresses are always two bytes aligned in memory? 
> Afaik this function needs it.

I don't think they need to be two bytes aligned, but I might be wrong.

> > In one case where the address was tested for broadcast and multicast
> > address, the broadcast address check can be omitted as broadcast is also
> > a multicast address.
> 
> We need to distinguish between these two types for different optimizations 
> (research is currently done for multicast over mesh - but currently not part 
> of batman-adv).

I was refering to the following part of the patch:

-       if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {
+       if (is_multicast_ether_addr(ethhdr->h_dest)) {

I think this change should be legitimate as the same branch is done for
multicast and broadcast addresses.

Thanks
Tobias
Sven Eckelmann Nov. 3, 2010, 10:56 a.m. UTC | #3 
On Wednesday 03 November 2010 11:25:12 Tobias Klauser wrote:
> On 2010-11-03 at 11:12:12 +0100, Sven Eckelmann <sven.eckelmann@gmx.de> 
wrote:
> > On Wednesday 03 November 2010 10:59:02 you wrote:
> > > Replace custom ethernet address check functions by calls to the helpers
> > > in linux/etherdevice.h
> > 
> > Have you proven that the addresses are always two bytes aligned in
> > memory? Afaik this function needs it.
> 
> I don't think they need to be two bytes aligned, but I might be wrong.

compare_ether_addr uses a two byte pointer to access 3x two bytes. This makes 
it necessary to have all those 3 bytes aligned to 2 byte boundaries. Otherwise 
the compiler has to generate special instructions on architectures which don't 
support loads on non-aligned addresses. Usually he doesn't do it unless he has 
some indications that it is necessary (__attribute__ ((packed)) for example).

There is also documentation available on that topic in 
Documentation/unaligned-memory-access.txt

And maybe it is good to use is_broadcast_ether_addr, but leave 
compare_ether_addr part open (or prove that we always have those two operands 
correctly aligned).

> > > In one case where the address was tested for broadcast and multicast
> > > address, the broadcast address check can be omitted as broadcast is
> > > also a multicast address.
> > 
> > We need to distinguish between these two types for different
> > optimizations (research is currently done for multicast over mesh - but
> > currently not part of batman-adv).
> 
> I was refering to the following part of the patch:
> 
> -       if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {
> +       if (is_multicast_ether_addr(ethhdr->h_dest)) {
> 
> I think this change should be legitimate as the same branch is done for
> multicast and broadcast addresses.

Yes, in that situation it is correct. I was talking more about the complete 
bcast vs. multicast in batman-adv and didn't look at your patch.

Best regards,
	Sven
Sven Eckelmann Nov. 3, 2010, 11:04 a.m. UTC | #4 
On Wednesday 03 November 2010 11:56:19 Sven Eckelmann wrote:
> On Wednesday 03 November 2010 11:25:12 Tobias Klauser wrote:
> > On 2010-11-03 at 11:12:12 +0100, Sven Eckelmann <sven.eckelmann@gmx.de>
> 
> wrote:
> > > On Wednesday 03 November 2010 10:59:02 you wrote:
> > > > Replace custom ethernet address check functions by calls to the
> > > > helpers in linux/etherdevice.h
> > > 
> > > Have you proven that the addresses are always two bytes aligned in
> > > memory? Afaik this function needs it.
> > 
> > I don't think they need to be two bytes aligned, but I might be wrong.
> 
> compare_ether_addr uses a two byte pointer to access 3x two bytes. This
> makes it necessary to have all those 3 bytes aligned to 2 byte boundaries.

3x two bytes for each ethernet address == 6x two bytes and not 3 bytes... I 
don't know why I wrote that.

Best regards,
	Sven
Marek Lindner Nov. 3, 2010, noon UTC | #5 
On Wednesday 03 November 2010 11:25:12 Tobias Klauser wrote:
> I was refering to the following part of the patch:
> 
> -       if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {
> +       if (is_multicast_ether_addr(ethhdr->h_dest)) {
> 
> I think this change should be legitimate as the same branch is done for
> multicast and broadcast addresses.

Soon we will have different code paths for broadcast and multicast right at 
this spot as multicast can be optimized further. But I think we can merge the 
change for the time being.

Regards,
Marek
diff mbox

Patch

diff --git a/drivers/staging/batman-adv/main.c b/drivers/staging/batman-adv/main.c
index 0587940..6ea6420 100644
--- a/drivers/staging/batman-adv/main.c
+++ b/drivers/staging/batman-adv/main.c
@@ -149,7 +149,7 @@  void dec_module_count(void)
 
 int compare_orig(void *data1, void *data2)
 {
-	return (memcmp(data1, data2, ETH_ALEN) == 0 ? 1 : 0);
+	return (compare_ether_addr(data1, data2) == 0 ? 1 : 0);
 }
 
 /* hashfunction to choose an entry in a hash table of given size */
@@ -192,16 +192,6 @@  int is_my_mac(uint8_t *addr)
 
 }
 
-int is_bcast(uint8_t *addr)
-{
-	return (addr[0] == (uint8_t)0xff) && (addr[1] == (uint8_t)0xff);
-}
-
-int is_mcast(uint8_t *addr)
-{
-	return *addr & 0x01;
-}
-
 module_init(batman_init);
 module_exit(batman_exit);
 
diff --git a/drivers/staging/batman-adv/main.h b/drivers/staging/batman-adv/main.h
index 5e3f516..14d567d 100644
--- a/drivers/staging/batman-adv/main.h
+++ b/drivers/staging/batman-adv/main.h
@@ -109,6 +109,7 @@ 
 #include <linux/mutex.h>	/* mutex */
 #include <linux/module.h>	/* needed by all modules */
 #include <linux/netdevice.h>	/* netdevice */
+#include <linux/etherdevice.h>
 #include <linux/if_ether.h>	/* ethernet header */
 #include <linux/poll.h>		/* poll_table */
 #include <linux/kthread.h>	/* kernel threads */
@@ -138,8 +139,6 @@  void dec_module_count(void);
 int compare_orig(void *data1, void *data2);
 int choose_orig(void *data, int32_t size);
 int is_my_mac(uint8_t *addr);
-int is_bcast(uint8_t *addr);
-int is_mcast(uint8_t *addr);
 
 #ifdef CONFIG_BATMAN_ADV_DEBUG
 int debug_log(struct bat_priv *bat_priv, char *fmt, ...);
diff --git a/drivers/staging/batman-adv/routing.c b/drivers/staging/batman-adv/routing.c
index 9010263..d42c165 100644
--- a/drivers/staging/batman-adv/routing.c
+++ b/drivers/staging/batman-adv/routing.c
@@ -756,11 +756,11 @@  int recv_bat_packet(struct sk_buff *skb, struct batman_if *batman_if)
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* packet with broadcast indication but unicast recipient */
-	if (!is_bcast(ethhdr->h_dest))
+	if (!is_broadcast_ether_addr(ethhdr->h_dest))
 		return NET_RX_DROP;
 
 	/* packet with broadcast sender address */
-	if (is_bcast(ethhdr->h_source))
+	if (is_broadcast_ether_addr(ethhdr->h_source))
 		return NET_RX_DROP;
 
 	/* create a copy of the skb, if needed, to modify it. */
@@ -933,11 +933,11 @@  int recv_icmp_packet(struct sk_buff *skb, struct batman_if *recv_if)
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* packet with unicast indication but broadcast recipient */
-	if (is_bcast(ethhdr->h_dest))
+	if (is_broadcast_ether_addr(ethhdr->h_dest))
 		return NET_RX_DROP;
 
 	/* packet with broadcast sender address */
-	if (is_bcast(ethhdr->h_source))
+	if (is_broadcast_ether_addr(ethhdr->h_source))
 		return NET_RX_DROP;
 
 	/* not for me */
@@ -1107,11 +1107,11 @@  static int check_unicast_packet(struct sk_buff *skb, int hdr_size)
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* packet with unicast indication but broadcast recipient */
-	if (is_bcast(ethhdr->h_dest))
+	if (is_broadcast_ether_addr(ethhdr->h_dest))
 		return -1;
 
 	/* packet with broadcast sender address */
-	if (is_bcast(ethhdr->h_source))
+	if (is_broadcast_ether_addr(ethhdr->h_source))
 		return -1;
 
 	/* not for me */
@@ -1283,11 +1283,11 @@  int recv_bcast_packet(struct sk_buff *skb, struct batman_if *recv_if)
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	/* packet with broadcast indication but unicast recipient */
-	if (!is_bcast(ethhdr->h_dest))
+	if (!is_broadcast_ether_addr(ethhdr->h_dest))
 		return NET_RX_DROP;
 
 	/* packet with broadcast sender address */
-	if (is_bcast(ethhdr->h_source))
+	if (is_broadcast_ether_addr(ethhdr->h_source))
 		return NET_RX_DROP;
 
 	/* ignore broadcasts sent by myself */
diff --git a/drivers/staging/batman-adv/soft-interface.c b/drivers/staging/batman-adv/soft-interface.c
index 3904db9..820e141 100644
--- a/drivers/staging/batman-adv/soft-interface.c
+++ b/drivers/staging/batman-adv/soft-interface.c
@@ -140,7 +140,7 @@  int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
 	hna_local_add(soft_iface, ethhdr->h_source);
 
 	/* ethernet packet should be broadcasted */
-	if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {
+	if (is_multicast_ether_addr(ethhdr->h_dest)) {
 		if (!bat_priv->primary_if)
 			goto dropped;
 
diff --git a/drivers/staging/batman-adv/vis.c b/drivers/staging/batman-adv/vis.c
index 3d2c1bc..c98a065 100644
--- a/drivers/staging/batman-adv/vis.c
+++ b/drivers/staging/batman-adv/vis.c
@@ -470,7 +470,7 @@  void receive_client_update_packet(struct bat_priv *bat_priv,
 	int are_target = 0;
 
 	/* clients shall not broadcast. */
-	if (is_bcast(vis_packet->target_orig))
+	if (is_broadcast_ether_addr(vis_packet->target_orig))
 		return;
 
 	/* Are we the target for this VIS packet? */
@@ -747,7 +747,7 @@  static void send_vis_packet(struct bat_priv *bat_priv, struct vis_info *info)
 	       ETH_ALEN);
 	packet->ttl--;
 
-	if (is_bcast(packet->target_orig))
+	if (is_broadcast_ether_addr(packet->target_orig))
 		broadcast_vis_packet(bat_priv, info);
 	else
 		unicast_vis_packet(bat_priv, info);