[PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[Greg Rose]

I'm not sure why this hasn't been done before because it seems obvious,
so maybe there is some reason that memcpy is used instead of
ether_addr_copy in this code.  But let's try this anyway.

Change memcpy to ether_addr_copy.

Signed-off-by: Greg Rose <grose@lightfleet.com>
---
 net/ethernet/eth.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 66dff5e..cbcdb97 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -95,10 +95,10 @@ int eth_header(struct sk_buff *skb, struct net_device *dev,
 
 	if (!saddr)
 		saddr = dev->dev_addr;
-	memcpy(eth->h_source, saddr, ETH_ALEN);
+	ether_addr_copy(eth->h_source, saddr);
 
 	if (daddr) {
-		memcpy(eth->h_dest, daddr, ETH_ALEN);
+		ether_addr_copy(eth->h_dest, daddr);
 		return ETH_HLEN;
 	}
 
@@ -211,7 +211,7 @@ EXPORT_SYMBOL(eth_type_trans);
 int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
 {
 	const struct ethhdr *eth = eth_hdr(skb);
-	memcpy(haddr, eth->h_source, ETH_ALEN);
+	ether_addr_copy(haddr, eth->h_source);
 	return ETH_ALEN;
 }
 EXPORT_SYMBOL(eth_header_parse);
@@ -236,8 +236,8 @@ int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16
 		return -1;
 
 	eth->h_proto = type;
-	memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
-	memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
+	ether_addr_copy(eth->h_source, dev->dev_addr);
+	ether_addr_copy(eth->h_dest, neigh->ha);
 	hh->hh_len = ETH_HLEN;
 	return 0;
 }
@@ -255,8 +255,8 @@ void eth_header_cache_update(struct hh_cache *hh,
 			     const struct net_device *dev,
 			     const unsigned char *haddr)
 {
-	memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
-	       haddr, ETH_ALEN);
+	ether_addr_copy(((u8 *)hh->hh_data) +
+			HH_DATA_OFF(sizeof(struct ethhdr)), haddr);
 }
 EXPORT_SYMBOL(eth_header_cache_update);
 
@@ -286,7 +286,7 @@ void eth_commit_mac_addr_change(struct net_device *dev, void *p)
 {
 	struct sockaddr *addr = p;
 
-	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+	ether_addr_copy(dev->dev_addr, addr->sa_data);
 }
 EXPORT_SYMBOL(eth_commit_mac_addr_change);
 
-- 
1.8.3.1

Re: [PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[Joe Perches]

On Wed, 2016-08-31 at 09:32 -0700, Greg Rose wrote:
> I'm not sure why this hasn't been done before because it seems obvious,
> so maybe there is some reason that memcpy is used instead of
> ether_addr_copy in this code.  But let's try this anyway.
>
> Change memcpy to ether_addr_copy.

I looked at this once and gave up given the need to verify all
the possible callers that require an __aligned(2) source address.

Re: [PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[Greg]

On Wed, 2016-08-31 at 09:41 -0700, Joe Perches wrote:
> On Wed, 2016-08-31 at 09:32 -0700, Greg Rose wrote:
> > I'm not sure why this hasn't been done before because it seems obvious,
> > so maybe there is some reason that memcpy is used instead of
> > ether_addr_copy in this code.  But let's try this anyway.
> >
> > Change memcpy to ether_addr_copy.
> 
> I looked at this once and gave up given the need to verify all
> the possible callers that require an __aligned(2) source address.
> 

Ha, I figured there must be some reason for it.  OK, patch withdrawn.

Thanks!

Re: [PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[Eric Dumazet]

On Wed, 2016-08-31 at 09:32 -0700, Greg Rose wrote:
> I'm not sure why this hasn't been done before because it seems obvious,
> so maybe there is some reason that memcpy is used instead of
> ether_addr_copy in this code.  But let's try this anyway.
> 
> Change memcpy to ether_addr_copy.

...

>  
> @@ -211,7 +211,7 @@ EXPORT_SYMBOL(eth_type_trans);
>  int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
>  {
>  	const struct ethhdr *eth = eth_hdr(skb);
> -	memcpy(haddr, eth->h_source, ETH_ALEN);
> +	ether_addr_copy(haddr, eth->h_source);


Please carefully read ether_addr_copy() comments.

Not all arches are like x86

Re: [PATCH] net/ethernet: Use ether_addr_copy rather than memcpy

[Greg]

On Wed, 2016-08-31 at 11:32 -0700, Eric Dumazet wrote:
> On Wed, 2016-08-31 at 09:32 -0700, Greg Rose wrote:
> > I'm not sure why this hasn't been done before because it seems obvious,
> > so maybe there is some reason that memcpy is used instead of
> > ether_addr_copy in this code.  But let's try this anyway.
> > 
> > Change memcpy to ether_addr_copy.
> 
> ...
> 
> >  
> > @@ -211,7 +211,7 @@ EXPORT_SYMBOL(eth_type_trans);
> >  int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr)
> >  {
> >  	const struct ethhdr *eth = eth_hdr(skb);
> > -	memcpy(haddr, eth->h_source, ETH_ALEN);
> > +	ether_addr_copy(haddr, eth->h_source);
> 
> 
> Please carefully read ether_addr_copy() comments.
> 
> Not all arches are like x86

Thanks Eric, Joe set me straight already.

- Greg
> 
> 
>