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Date: Wed, 6 Jun 2012 01:41:21 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: Hans Schillstrom <hans@...illstrom.com>
Cc: kaber@...sh.net, jengelh@...ozas.de,
netfilter-devel@...r.kernel.org, netdev@...r.kernel.org,
dan.carpenter@...cle.com, hans.schillstrom@...csson.com
Subject: Re: [v2 PATCH] netfilter: xt_HMARK: fix endian bugs and warnings
On Fri, May 18, 2012 at 10:35:46AM +0200, Hans Schillstrom wrote:
> A mix of u32 and __be32 causes endian warning.
> The hash value produced is now the same for big and little endian machines.
> i.e. a mix of Big and Little endian in a cluster is now possible.
Applied with minor glitches, Thanks Hans.
I have rewritten the description.
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> Signed-off-by: Hans Schillstrom <hans@...illstrom.com>
> ---
> include/linux/netfilter/xt_HMARK.h | 5 +++
> net/netfilter/xt_HMARK.c | 69 ++++++++++++++++++++----------------
> 2 files changed, 43 insertions(+), 31 deletions(-)
>
> diff --git a/include/linux/netfilter/xt_HMARK.h b/include/linux/netfilter/xt_HMARK.h
> index abb1650..826fc58 100644
> --- a/include/linux/netfilter/xt_HMARK.h
> +++ b/include/linux/netfilter/xt_HMARK.h
> @@ -27,7 +27,12 @@ union hmark_ports {
> __u16 src;
> __u16 dst;
> } p16;
> + struct {
> + __be16 src;
> + __be16 dst;
> + } b16;
> __u32 v32;
> + __be32 b32;
> };
>
> struct xt_hmark_info {
> diff --git a/net/netfilter/xt_HMARK.c b/net/netfilter/xt_HMARK.c
> index 0a96a43..5119666 100644
> --- a/net/netfilter/xt_HMARK.c
> +++ b/net/netfilter/xt_HMARK.c
> @@ -32,13 +32,13 @@ MODULE_ALIAS("ipt_HMARK");
> MODULE_ALIAS("ip6t_HMARK");
>
> struct hmark_tuple {
> - u32 src;
> - u32 dst;
> + __be32 src;
> + __be32 dst;
> union hmark_ports uports;
> uint8_t proto;
I have converted this uint8_t to u8. I think I'm responsible for that
slipped through.
> };
>
> -static inline u32 hmark_addr6_mask(const __u32 *addr32, const __u32 *mask)
> +static inline __be32 hmark_addr6_mask(const __be32 *addr32, const __be32 *mask)
> {
> return (addr32[0] & mask[0]) ^
> (addr32[1] & mask[1]) ^
> @@ -46,8 +46,8 @@ static inline u32 hmark_addr6_mask(const __u32 *addr32, const __u32 *mask)
> (addr32[3] & mask[3]);
> }
>
> -static inline u32
> -hmark_addr_mask(int l3num, const __u32 *addr32, const __u32 *mask)
> +static inline __be32
> +hmark_addr_mask(int l3num, const __be32 *addr32, const __be32 *mask)
> {
> switch (l3num) {
> case AF_INET:
> @@ -58,6 +58,22 @@ hmark_addr_mask(int l3num, const __u32 *addr32, const __u32 *mask)
> return 0;
> }
>
> +static inline void hmark_swap_ports(union hmark_ports *uports,
> + const struct xt_hmark_info *info)
> +{
> + union hmark_ports hp;
> + u16 src,dst;
> +
> + hp.b32 = (uports->b32 & info->port_mask.b32) | info->port_set.b32;
> + src = ntohs(hp.b16.src);
> + dst = ntohs(hp.b16.dst);
> +
> + if (dst > src)
> + uports->v32 = (dst << 16) | src;
> + else
> + uports->v32 = (src << 16) | dst;
> +}
> +
> static int
> hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t,
> const struct xt_hmark_info *info)
> @@ -74,22 +90,19 @@ hmark_ct_set_htuple(const struct sk_buff *skb, struct hmark_tuple *t,
> otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
> rtuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
>
> - t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.all,
> - info->src_mask.all);
> - t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.all,
> - info->dst_mask.all);
> + t->src = hmark_addr_mask(otuple->src.l3num, otuple->src.u3.ip6,
> + info->src_mask.ip6);
> + t->dst = hmark_addr_mask(otuple->src.l3num, rtuple->src.u3.ip6,
> + info->dst_mask.ip6);
>
> if (info->flags & XT_HMARK_FLAG(XT_HMARK_METHOD_L3))
> return 0;
>
> t->proto = nf_ct_protonum(ct);
> if (t->proto != IPPROTO_ICMP) {
> - t->uports.p16.src = otuple->src.u.all;
> - t->uports.p16.dst = rtuple->src.u.all;
> - t->uports.v32 = (t->uports.v32 & info->port_mask.v32) |
> - info->port_set.v32;
> - if (t->uports.p16.dst < t->uports.p16.src)
> - swap(t->uports.p16.dst, t->uports.p16.src);
> + t->uports.b16.src = otuple->src.u.all;
> + t->uports.b16.dst = rtuple->src.u.all;
> + hmark_swap_ports(&t->uports, info);
> }
>
> return 0;
> @@ -102,11 +115,13 @@ static inline u32
I've added this comment on top of hmark_hash:
/* This hash function is endian independent, to ensure consistent hashing if
* the cluster is composed of big and little endian systems. */
In case that someone is curious about all those conversions.
> hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info)
[...]
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