From: Evgeniy Polyakov <zbr@ioremap•net>
To: Patrick McHardy <kaber@trash•net>
Cc: netdev@vger•kernel.org, David Miller <davem@davemloft•net>,
"Paul E. McKenney" <paulmck@linux•vnet.ibm.com>,
Netfilter Development Mailinglist
<netfilter-devel@vger•kernel.org>,
Jan Engelhardt <jengelh@medozas•de>
Subject: Re: Passive OS fingerprint xtables match.
Date: Sun, 7 Jun 2009 19:12:18 +0400 [thread overview]
Message-ID: <20090607151218.GA31757@ioremap.net> (raw)
In-Reply-To: <4A290767.6080202@trash.net>
Hi Patrick.
I've added mentioned cleanups except the one described below.
On Fri, Jun 05, 2009 at 01:54:15PM +0200, Patrick McHardy (kaber@trash•net) wrote:
> >+ tcp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr),
> >&_tcph);
> >+ if (!tcp)
> >+ return false;
> >+
> >+ if (!tcp->syn)
> >+ return false;
> >+
> >+ totlen = ntohs(ip->tot_len);
> >+ df = ntohs(ip->frag_off) & IP_DF;
> >+ window = ntohs(tcp->window);
> >+
> >+ if (tcp->doff * 4 > sizeof(struct tcphdr)) {
> >+ optsize = tcp->doff * 4 - sizeof(struct tcphdr);
>
> tcp_optlen()?
TCP header is potentially copied above and transport header may be not
set, so I work with that part of skb without assuming it was previously
set by lower layers.
> >+ if (info->flags & XT_OSF_LOG) {
> >+ if (info->loglevel != XT_OSF_LOGLEVEL_ALL_KNOWN)
> >+ nf_log_packet(p->hooknum, 0, skb, p->in,
> >p->out, NULL,
> >+ "window: %u, mss: %u, totlen: %u,
> >df: %d, ttl: %u : ",
> >+ window, mss, totlen, df, ip->ttl);
>
> nf_log_packet() can pass the entire packet to userspace. Header-field
> extraction should be done by whatever is logging in userspace. This
> looks very much like debugging anyways, where is the actual message?
Message itself is 'printed' couple of lines below, but apparently it is
not needed for nf_log_packet, only for the printk()-based debug, so I
dropped that part.
--
Evgeniy Polyakov
next prev parent reply other threads:[~2009-06-07 15:12 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-04 16:22 Passive OS fingerprint xtables match Evgeniy Polyakov
2009-06-05 11:54 ` Patrick McHardy
2009-06-05 13:10 ` Jan Engelhardt
2009-06-05 13:30 ` Patrick McHardy
2009-06-05 13:44 ` Jan Engelhardt
2009-06-07 15:12 ` Evgeniy Polyakov [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-06-07 15:17 Evgeniy Polyakov
2009-06-08 15:06 ` Patrick McHardy
2009-06-08 17:25 ` Evgeniy Polyakov
2009-03-26 14:14 Evgeniy Polyakov
2009-03-26 14:18 ` Patrick McHardy
2009-03-26 14:59 ` Evgeniy Polyakov
2009-03-26 15:08 ` Patrick McHardy
2009-03-26 15:41 ` Evgeniy Polyakov
2009-03-26 15:47 ` Patrick McHardy
2009-03-30 6:20 ` Evgeniy Polyakov
2009-05-01 20:15 ` Evgeniy Polyakov
2009-03-10 15:13 Evgeniy Polyakov
2009-03-10 16:01 ` Evgeniy Polyakov
2009-03-10 16:07 ` Jan Engelhardt
2009-03-11 21:43 ` Evgeniy Polyakov
2009-03-10 21:01 ` Jesper Dangaard Brouer
2009-03-10 21:54 ` Evgeniy Polyakov
2009-03-16 14:40 ` Patrick McHardy
2009-03-11 9:54 ` Pablo Neira Ayuso
2009-03-11 10:00 ` Evgeniy Polyakov
2009-03-16 14:42 ` Patrick McHardy
2009-02-12 17:12 Evgeniy Polyakov
2009-02-12 17:42 ` Paul E. McKenney
2009-02-12 17:51 ` Evgeniy Polyakov
2009-02-12 20:41 ` Paul E. McKenney
2009-02-18 14:55 ` Patrick McHardy
2009-02-12 18:22 ` Jan Engelhardt
2009-02-12 18:57 ` Evgeniy Polyakov
2009-02-12 20:12 ` Jan Engelhardt
2009-02-13 13:03 ` Evgeniy Polyakov
2009-02-13 13:51 ` Jan Engelhardt
2009-02-13 14:22 ` Evgeniy Polyakov
2009-02-13 14:41 ` Jan Engelhardt
2009-02-15 17:32 ` Evgeniy Polyakov
2009-02-18 15:02 ` Patrick McHardy
2009-02-18 15:07 ` Evgeniy Polyakov
2009-02-18 15:30 ` Jan Engelhardt
2009-02-19 11:56 ` Evgeniy Polyakov
2009-02-18 15:00 ` Patrick McHardy
2009-02-18 15:28 ` Jan Engelhardt
2009-02-18 15:14 ` Patrick McHardy
2009-01-29 17:20 Evgeniy Polyakov
2009-01-30 1:05 ` Paul E. McKenney
2009-02-09 16:09 ` Patrick McHardy
2009-02-13 12:49 ` Evgeniy Polyakov
2009-01-27 22:55 Evgeniy Polyakov
2009-01-29 3:36 ` Paul E. McKenney
2009-01-29 15:03 ` Evgeniy Polyakov
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