linux-kernel - Re: [nf-next] netfilter: extend SRH match to support matching previous, next and last SID

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Date:   Mon, 23 Apr 2018 22:01:48 +0200
From:   Ahmed Abdelsalam <amsalam20@...il.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>
Cc:     fw@...len.de, davem@...emloft.net, dav.lebrun@...il.com,
        linux-kernel@...r.kernel.org, netfilter-devel@...r.kernel.org,
        coreteam@...filter.org, netdev@...r.kernel.org
Subject: Re: [nf-next] netfilter: extend SRH match to support matching
 previous, next and last SID

On Mon, 23 Apr 2018 19:30:47 +0200
Pablo Neira Ayuso <pablo@...filter.org> wrote:

> On Mon, Apr 23, 2018 at 05:48:22AM -0500, Ahmed Abdelsalam wrote:
> > Signed-off-by: Ahmed Abdelsalam <amsalam20@...il.com>
> > ---
> >  include/uapi/linux/netfilter_ipv6/ip6t_srh.h | 22 +++++++++++++--
> >  net/ipv6/netfilter/ip6t_srh.c                | 41 +++++++++++++++++++++++++++-
> >  2 files changed, 60 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h
> > index f3cc0ef..9808382 100644
> > --- a/include/uapi/linux/netfilter_ipv6/ip6t_srh.h
> > +++ b/include/uapi/linux/netfilter_ipv6/ip6t_srh.h
> > @@ -17,7 +17,10 @@
> >  #define IP6T_SRH_LAST_GT        0x0100
> >  #define IP6T_SRH_LAST_LT        0x0200
> >  #define IP6T_SRH_TAG            0x0400
> > -#define IP6T_SRH_MASK           0x07FF
> > +#define IP6T_SRH_PSID           0x0800
> > +#define IP6T_SRH_NSID           0x1000
> > +#define IP6T_SRH_LSID           0x2000
> > +#define IP6T_SRH_MASK           0x3FFF
> >  
> >  /* Values for "mt_invflags" field in struct ip6t_srh */
> >  #define IP6T_SRH_INV_NEXTHDR    0x0001
> > @@ -31,7 +34,10 @@
> >  #define IP6T_SRH_INV_LAST_GT    0x0100
> >  #define IP6T_SRH_INV_LAST_LT    0x0200
> >  #define IP6T_SRH_INV_TAG        0x0400
> > -#define IP6T_SRH_INV_MASK       0x07FF
> > +#define IP6T_SRH_INV_PSID       0x0800
> > +#define IP6T_SRH_INV_NSID       0x1000
> > +#define IP6T_SRH_INV_LSID       0x2000
> > +#define IP6T_SRH_INV_MASK       0x3FFF
> >  
> >  /**
> >   *      struct ip6t_srh - SRH match options
> > @@ -40,6 +46,12 @@
> >   *      @ segs_left: Segments left field of SRH
> >   *      @ last_entry: Last entry field of SRH
> >   *      @ tag: Tag field of SRH
> > + *      @ psid_addr: Address of previous SID in SRH SID list
> > + *      @ nsid_addr: Address of NEXT SID in SRH SID list
> > + *      @ lsid_addr: Address of LAST SID in SRH SID list
> > + *      @ psid_msk: Mask of previous SID in SRH SID list
> > + *      @ nsid_msk: Mask of next SID in SRH SID list
> > + *      @ lsid_msk: MAsk of last SID in SRH SID list
> >   *      @ mt_flags: match options
> >   *      @ mt_invflags: Invert the sense of match options
> >   */
> > @@ -50,6 +62,12 @@ struct ip6t_srh {
> >  	__u8                    segs_left;
> >  	__u8                    last_entry;
> >  	__u16                   tag;
> > +	struct in6_addr		psid_addr;
> > +	struct in6_addr		nsid_addr;
> > +	struct in6_addr		lsid_addr;
> > +	struct in6_addr		psid_msk;
> > +	struct in6_addr		nsid_msk;
> > +	struct in6_addr		lsid_msk;
> 
> This is changing something exposed through UAPI, so you will need a
> new revision for this.

Could you please advice what should be done in this case? 

> 
> >  	__u16                   mt_flags;
> >  	__u16                   mt_invflags;
> >  };
> > diff --git a/net/ipv6/netfilter/ip6t_srh.c b/net/ipv6/netfilter/ip6t_srh.c
> > index 33719d5..2b5cc73 100644
> > --- a/net/ipv6/netfilter/ip6t_srh.c
> > +++ b/net/ipv6/netfilter/ip6t_srh.c
> > @@ -30,7 +30,9 @@ static bool srh_mt6(const struct sk_buff *skb, struct xt_action_param *par)
> >  	const struct ip6t_srh *srhinfo = par->matchinfo;
> >  	struct ipv6_sr_hdr *srh;
> >  	struct ipv6_sr_hdr _srh;
> > -	int hdrlen, srhoff = 0;
> > +	int hdrlen, psidoff, nsidoff, lsidoff, srhoff = 0;
> > +	struct in6_addr *psid, *nsid, *lsid;
> > +	struct in6_addr _psid, _nsid, _lsid;
> 
> Could you rearrange variable definitions? ie. longest line first, eg.
> 
> 	int hdrlen, psidoff, nsidoff, lsidoff, srhoff = 0;
>   	const struct ip6t_srh *srhinfo = par->matchinfo;
> 	struct in6_addr *psid, *nsid, *lsid;
>   	struct ipv6_sr_hdr *srh;
>   	struct ipv6_sr_hdr _srh;
> 

Ok I will re-arrange them in reverse christmas tree form. 

Ahmed 

-- 
Ahmed Abdelsalam <amsalam20@...il.com>