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Date: Wed, 16 Nov 2022 19:51:40 -0500
From: Xin Long <lucien.xin@...il.com>
To: Pablo Neira Ayuso <pablo@...filter.org>
Cc: network dev <netdev@...r.kernel.org>, dev@...nvswitch.org,
davem@...emloft.net, kuba@...nel.org,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Pravin B Shelar <pshelar@....org>,
Jamal Hadi Salim <jhs@...atatu.com>,
Cong Wang <xiyou.wangcong@...il.com>,
Jiri Pirko <jiri@...nulli.us>, Florian Westphal <fw@...len.de>,
Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
Davide Caratti <dcaratti@...hat.com>,
Eelco Chaudron <echaudro@...hat.com>,
Aaron Conole <aconole@...hat.com>
Subject: Re: [PATCH net-next 5/5] net: move the nat function to nf_nat_core
for ovs and tc
On Wed, Nov 16, 2022 at 4:54 PM Pablo Neira Ayuso <pablo@...filter.org> wrote:
>
> On Tue, Nov 15, 2022 at 10:50:57AM -0500, Xin Long wrote:
> > diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
> > index e29e4ccb5c5a..1c72b8caa24e 100644
> > --- a/net/netfilter/nf_nat_core.c
> > +++ b/net/netfilter/nf_nat_core.c
> > @@ -784,6 +784,137 @@ nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> > }
> > EXPORT_SYMBOL_GPL(nf_nat_inet_fn);
> >
> > +/* Modelled after nf_nat_ipv[46]_fn().
> > + * range is only used for new, uninitialized NAT state.
> > + * Returns either NF_ACCEPT or NF_DROP.
> > + */
> > +static int nf_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
> > + enum ip_conntrack_info ctinfo, int *action,
> > + const struct nf_nat_range2 *range,
> > + enum nf_nat_manip_type maniptype)
> > +{
> > + __be16 proto = skb_protocol(skb, true);
> > + int hooknum, err = NF_ACCEPT;
> > +
> > + /* See HOOK2MANIP(). */
> > + if (maniptype == NF_NAT_MANIP_SRC)
> > + hooknum = NF_INET_LOCAL_IN; /* Source NAT */
> > + else
> > + hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
> > +
> > + switch (ctinfo) {
> > + case IP_CT_RELATED:
> > + case IP_CT_RELATED_REPLY:
> > + if (proto == htons(ETH_P_IP) &&
> > + ip_hdr(skb)->protocol == IPPROTO_ICMP) {
> > + if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
> > + hooknum))
> > + err = NF_DROP;
> > + goto out;
> > + } else if (IS_ENABLED(CONFIG_IPV6) && proto == htons(ETH_P_IPV6)) {
> > + __be16 frag_off;
> > + u8 nexthdr = ipv6_hdr(skb)->nexthdr;
> > + int hdrlen = ipv6_skip_exthdr(skb,
> > + sizeof(struct ipv6hdr),
> > + &nexthdr, &frag_off);
> > +
> > + if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
> > + if (!nf_nat_icmpv6_reply_translation(skb, ct,
> > + ctinfo,
> > + hooknum,
> > + hdrlen))
> > + err = NF_DROP;
> > + goto out;
> > + }
> > + }
> > + /* Non-ICMP, fall thru to initialize if needed. */
> > + fallthrough;
> > + case IP_CT_NEW:
> > + /* Seen it before? This can happen for loopback, retrans,
> > + * or local packets.
> > + */
> > + if (!nf_nat_initialized(ct, maniptype)) {
> > + /* Initialize according to the NAT action. */
> > + err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
> > + /* Action is set up to establish a new
> > + * mapping.
> > + */
> > + ? nf_nat_setup_info(ct, range, maniptype)
> > + : nf_nat_alloc_null_binding(ct, hooknum);
> > + if (err != NF_ACCEPT)
> > + goto out;
> > + }
> > + break;
> > +
> > + case IP_CT_ESTABLISHED:
> > + case IP_CT_ESTABLISHED_REPLY:
> > + break;
> > +
> > + default:
> > + err = NF_DROP;
> > + goto out;
> > + }
> > +
> > + err = nf_nat_packet(ct, ctinfo, hooknum, skb);
> > + if (err == NF_ACCEPT)
> > + *action |= (1 << maniptype);
> > +out:
> > + return err;
> > +}
> > +
> > +int nf_ct_nat(struct sk_buff *skb, struct nf_conn *ct,
> > + enum ip_conntrack_info ctinfo, int *action,
> > + const struct nf_nat_range2 *range, bool commit)
> > +{
> > + enum nf_nat_manip_type maniptype;
> > + int err, ct_action = *action;
> > +
> > + *action = 0;
> > +
> > + /* Add NAT extension if not confirmed yet. */
> > + if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
> > + return NF_ACCEPT; /* Can't NAT. */
> > +
> > + if (ctinfo != IP_CT_NEW && (ct->status & IPS_NAT_MASK) &&
> > + (ctinfo != IP_CT_RELATED || commit)) {
> > + /* NAT an established or related connection like before. */
> > + if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
> > + /* This is the REPLY direction for a connection
> > + * for which NAT was applied in the forward
> > + * direction. Do the reverse NAT.
> > + */
> > + maniptype = ct->status & IPS_SRC_NAT
> > + ? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
> > + else
> > + maniptype = ct->status & IPS_SRC_NAT
> > + ? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
> > + } else if (ct_action & (1 << NF_NAT_MANIP_SRC)) {
> > + maniptype = NF_NAT_MANIP_SRC;
> > + } else if (ct_action & (1 << NF_NAT_MANIP_DST)) {
> > + maniptype = NF_NAT_MANIP_DST;
> > + } else {
> > + return NF_ACCEPT;
> > + }
> > +
> > + err = nf_ct_nat_execute(skb, ct, ctinfo, action, range, maniptype);
> > + if (err == NF_ACCEPT && ct->status & IPS_DST_NAT) {
> > + if (ct->status & IPS_SRC_NAT) {
> > + if (maniptype == NF_NAT_MANIP_SRC)
> > + maniptype = NF_NAT_MANIP_DST;
> > + else
> > + maniptype = NF_NAT_MANIP_SRC;
> > +
> > + err = nf_ct_nat_execute(skb, ct, ctinfo, action, range,
> > + maniptype);
> > + } else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
> > + err = nf_ct_nat_execute(skb, ct, ctinfo, action, NULL,
> > + NF_NAT_MANIP_SRC);
> > + }
> > + }
> > + return err;
> > +}
> > +EXPORT_SYMBOL_GPL(nf_ct_nat);
>
> I'd suggest you move this code to nf_nat_ovs.c or such so we remember
> these symbols are used by act_ct.c and ovs.
Good idea, do you think we should also create nf_conntrack_ovs.c
to have nf_ct_helper() and nf_ct_add_helper()?
which were added by:
https://lore.kernel.org/netdev/20221101150031.a6rtrgzwfd7kzknn@t14s.localdomain/T/
thanks.
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