On Wed, Sep 2, 2009 at 16:56, Patrick McHardy<kaber@xxxxxxxxx> wrote:
> Hannes Eder wrote:
>> Update the nf_conntrack tuple in reply direction, as we will see
>> traffic from the real server (RIP) to the client (CIP). Once this is
>> done we can use netfilters SNAT in POSTROUTING, especially with
>> xt_ipvs, to do source NAT, e.g.:
>>
>> % iptables -t nat -A POSTROUTING -m ipvs --vaddr 192.168.100.30/32 --vport 8080 \
>>> -j SNAT --to-source 192.168.10.10
>>
>
>> +static void
>> +ip_vs_update_conntrack(struct sk_buff *skb, struct ip_vs_conn *cp)
>> +{
>> + struct nf_conn *ct = (struct nf_conn *)skb->nfct;
>> +
>> + if (ct == NULL || ct == &nf_conntrack_untracked ||
>> + nf_ct_is_confirmed(ct))
>> + return;
>> +
>> + /*
>> + * The connection is not yet in the hashtable, so we update it.
>> + * CIP->VIP will remain the same, so leave the tuple in
>> + * IP_CT_DIR_ORIGINAL untouched. When the reply comes back from the
>> + * real-server we will see RIP->DIP.
>> + */
>> + ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3 = cp->daddr;
>> + /*
>> + * This will also take care of UDP and other protocols.
>> + */
>> + ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.tcp.port = cp->dport;
>> +}
>
> How does IPVS interact with conntrack helpers? If it does actually
> intend to use them (which will happen automatically), it might make
> sense to use nf_conntrack_alter_reply(), which will perform a new
> helper lookup based on the changed tuple.
Good point, I'll use nf_conntrack_alter_reply(). IHMO IPVS only deals
with ftp in a special way, I think something need to be done there as
well, I'll investigate that.
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