[PATCH 2/2] [NETFILTER] remove bogus hand-coded htonll()

[PATCH 2/2] [NETFILTER] remove bogus hand-coded htonll()

[Harald Welte]

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Hi Dave, please apply the appended patch.

I somehow thought I had fixed this quite some time ago. Probably I lost
it with some merge :(

Thanks,
-- 
- Harald Welte <laforge@netfilter.org>                 http://netfilter.org/
============================================================================
  "Fragmentation is like classful addressing -- an interesting early
   architectural error that shows how much experimentation was going
   on while IP was being designed."                    -- Paul Vixie

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[NETFILTER] remove bogus hand-coded htonll() from nenetlink_queue

htonll() is nothing else than cpu_to_be64(), so we'd rather call the
latter.

Signed-off-by: Harald Welte <laforge@netfilter.org>

---
commit 0905251a08bf51d5e2d1996c21fcdc5acfbbde13
tree a8072738e54f24b0d4392cf33252594d4a6848e1
parent e8d296c78dff8485c5cd90217b91433185a58871
author Harald Welte <laforge@netfilter.org> Sa, 03 Sep 2005 10:31:19 +0200
committer Harald Welte <laforge@netfilter.org> Sa, 03 Sep 2005 10:31:19 +0200

 net/netfilter/nfnetlink_queue.c |   15 ++-------------
 1 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -76,17 +76,6 @@ typedef int (*nfqnl_cmpfn)(struct nfqnl_
 
 static DEFINE_RWLOCK(instances_lock);
 
-u_int64_t htonll(u_int64_t in)
-{
-	u_int64_t out;
-	int i;
-
-	for (i = 0; i < sizeof(u_int64_t); i++)
-		((u_int8_t *)&out)[sizeof(u_int64_t)-1] = ((u_int8_t *)&in)[i];
-
-	return out;
-}
-
 #define INSTANCE_BUCKETS	16
 static struct hlist_head instance_table[INSTANCE_BUCKETS];
 
@@ -497,8 +486,8 @@ nfqnl_build_packet_message(struct nfqnl_
 	if (entry->skb->tstamp.off_sec) {
 		struct nfqnl_msg_packet_timestamp ts;
 
-		ts.sec = htonll(skb_tv_base.tv_sec + entry->skb->tstamp.off_sec);
-		ts.usec = htonll(skb_tv_base.tv_usec + entry->skb->tstamp.off_usec);
+		ts.sec = cpu_to_be64(skb_tv_base.tv_sec + entry->skb->tstamp.off_sec);
+		ts.usec = cpu_to_be64(skb_tv_base.tv_usec + entry->skb->tstamp.off_usec);
 
 		NFA_PUT(skb, NFQA_TIMESTAMP, sizeof(ts), &ts);
 	}

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Re: [PATCH 2/2] [NETFILTER] remove bogus hand-coded htonll()

[Jouni Malinen]

On Sat, Sep 03, 2005 at 10:43:15AM +0200, Harald Welte wrote:

> htonll() is nothing else than cpu_to_be64(), so we'd rather call the
> latter.

Actually, the htonll() implementation does not seem to be doing what
cpu_to_be64() is doing.. However, I would assume this is a bug in
htonll() and this change to use cpu_to_be64() is fixing that. Can this
bug cause any major problems in the current implementation?

> -u_int64_t htonll(u_int64_t in)
> -{
> -	u_int64_t out;
> -	int i;
> -
> -	for (i = 0; i < sizeof(u_int64_t); i++)
> -		((u_int8_t *)&out)[sizeof(u_int64_t)-1] = ((u_int8_t *)&in)[i];

I would assume that the first index should have had '-i' added to it, if
the purpose is to swap byte order.. The code here is leaving some
arbitrary data in 7 bytes of the 64-bit variable and setting
(u8*)&out[7] = (u8*)&in[7] in somewhat inefficient way ;-). In addition,
this looks more like swap-8-bytes-unconditionally than doing this based
on host byte order..

-- 
Jouni Malinen                                            PGP id EFC895FA

Re: [PATCH 2/2] [NETFILTER] remove bogus hand-coded htonll()

[Harald Welte]

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On Sat, Sep 03, 2005 at 09:54:25AM -0700, Jouni Malinen wrote:
> On Sat, Sep 03, 2005 at 10:43:15AM +0200, Harald Welte wrote:
> 
> > htonll() is nothing else than cpu_to_be64(), so we'd rather call the
> > latter.
> 
> Actually, the htonll() implementation does not seem to be doing what
> cpu_to_be64() is doing.. However, I would assume this is a bug in
> htonll() and this change to use cpu_to_be64() is fixing that. 

ACK.

> Can this bug cause any major problems in the current implementation?

the "current implementation" was only merged after 2.6.13 is released,
so I doubt anyone but the netfilter developers is using it yet.

> I would assume that the first index should have had '-i' added to it, if
> the purpose is to swap byte order.. The code here is leaving some
> arbitrary data in 7 bytes of the 64-bit variable and setting
> (u8*)&out[7] = (u8*)&in[7] in somewhat inefficient way ;-). In addition,
> this looks more like swap-8-bytes-unconditionally than doing this based
> on host byte order..

yes, yes, yes.  Somehow this ancient buggy implementation slipped into
mainline.  I know I had fixed this before.

So please let's all forget about this embarrassing htonll() and move on. 

-- 
- Harald Welte <laforge@netfilter.org>                 http://netfilter.org/
============================================================================
  "Fragmentation is like classful addressing -- an interesting early
   architectural error that shows how much experimentation was going
   on while IP was being designed."                    -- Paul Vixie

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