From: Pablo Neira Ayuso <pablo@netfilter.org>
To: fgao@ikuai8.com
Cc: kaber@trash.net, netfilter-devel@vger.kernel.org,
netdev@vger.kernel.org, gfree.wind@gmail.com,
Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH nf v3] netfilter: seqadj: Fix the wrong ack adjust for the RST packet without ack
Date: Thu, 22 Sep 2016 08:27:01 +0200 [thread overview]
Message-ID: <20160922062701.GA2240@salvia> (raw)
In-Reply-To: <1474510965-2049-1-git-send-email-fgao@ikuai8.com>
On top of Eric's comments.
On Thu, Sep 22, 2016 at 10:22:45AM +0800, fgao@ikuai8.com wrote:
> diff --git a/net/netfilter/nf_conntrack_seqadj.c b/net/netfilter/nf_conntrack_seqadj.c
> index dff0f0c..3bd9c7e 100644
> --- a/net/netfilter/nf_conntrack_seqadj.c
> +++ b/net/netfilter/nf_conntrack_seqadj.c
> @@ -179,30 +179,34 @@ int nf_ct_seq_adjust(struct sk_buff *skb,
>
> tcph = (void *)skb->data + protoff;
> spin_lock_bh(&ct->lock);
> +
> if (after(ntohl(tcph->seq), this_way->correction_pos))
> seqoff = this_way->offset_after;
> else
> seqoff = this_way->offset_before;
>
> - if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
> - other_way->correction_pos))
> - ackoff = other_way->offset_after;
> - else
> - ackoff = other_way->offset_before;
> -
> newseq = htonl(ntohl(tcph->seq) + seqoff);
> - newack = htonl(ntohl(tcph->ack_seq) - ackoff);
> -
> inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, false);
> - inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack,
> - false);
> -
> - pr_debug("Adjusting sequence number from %u->%u, ack from %u->%u\n",
> - ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),
> - ntohl(newack));
>
> + pr_debug("Adjusting sequence number from %u->%u\n",
> + ntohl(tcph->seq), ntohl(newseq));
> tcph->seq = newseq;
> - tcph->ack_seq = newack;
> +
> + if (likely(tcph->ack)) {
I'd suggest:
if (!tcph->ack)
goto out;
given gcc sets goto branch as unlikely already, then you place an "out"
label...
> + if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
> + other_way->correction_pos))
> + ackoff = other_way->offset_after;
> + else
> + ackoff = other_way->offset_before;
> +
> + newack = htonl(ntohl(tcph->ack_seq) - ackoff);
> + inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq,
> + newack, false);
> +
> + pr_debug("Adjusting ack number from %u->%u\n",
> + ntohl(tcph->ack_seq), ntohl(newack));
> + tcph->ack_seq = newack;
> + }
>
> res = nf_ct_sack_adjust(skb, protoff, tcph, ct, ctinfo);
out: <- here
> spin_unlock_bh(&ct->lock);
This will get you a smaller patch fix.
prev parent reply other threads:[~2016-09-22 6:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-22 2:22 [PATCH nf v3] netfilter: seqadj: Fix the wrong ack adjust for the RST packet without ack fgao
2016-09-22 5:20 ` Eric Dumazet
2016-09-22 6:27 ` Pablo Neira Ayuso [this message]
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