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Message-ID: <20221123151335.ssrnv7jfrdugmcgg@t14s.localdomain>
Date: Wed, 23 Nov 2022 12:13:35 -0300
From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To: Xin Long <lucien.xin@...il.com>
Cc: dev@...nvswitch.org, ovs-dev@...nvswitch.org,
Davide Caratti <dcaratti@...hat.com>,
Jiri Pirko <jiri@...nulli.us>,
network dev <netdev@...r.kernel.org>,
Paul Blakey <paulb@...dia.com>,
Florian Westphal <fw@...len.de>,
Jamal Hadi Salim <jhs@...atatu.com>,
Ilya Maximets <i.maximets@....org>,
Eric Dumazet <edumazet@...gle.com>,
Cong Wang <xiyou.wangcong@...il.com>, kuba@...nel.org,
Paolo Abeni <pabeni@...hat.com>, davem@...emloft.net,
Pablo Neira Ayuso <pablo@...filter.org>
Subject: Re: [ovs-dev] [PATCHv2 net-next 5/5] net: move the nat function to
nf_nat_ovs for ovs and tc
On Wed, Nov 23, 2022 at 12:09:55PM -0300, Marcelo Ricardo Leitner wrote:
> On Tue, Nov 22, 2022 at 12:32:21PM -0500, Xin Long wrote:
> > +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);
> > diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
> > index cc643a556ea1..d03c75165663 100644
> > --- a/net/openvswitch/conntrack.c
> > +++ b/net/openvswitch/conntrack.c
> > @@ -726,144 +726,27 @@ static void ovs_nat_update_key(struct sw_flow_key *key,
> > }
> > }
> >
> > -/* 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 ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
> > - enum ip_conntrack_info ctinfo,
> > - const struct nf_nat_range2 *range,
> > - enum nf_nat_manip_type maniptype, struct sw_flow_key *key)
> > -{
> > - 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 (IS_ENABLED(CONFIG_NF_NAT) &&
> > - skb->protocol == 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) &&
> > - skb->protocol == 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);
> > -out:
> > - /* Update the flow key if NAT successful. */
> > - if (err == NF_ACCEPT)
> > - ovs_nat_update_key(key, skb, maniptype);
> > -
> > - return err;
> > -}
> > -
> > /* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */
> > static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
> > const struct ovs_conntrack_info *info,
> > struct sk_buff *skb, struct nf_conn *ct,
> > enum ip_conntrack_info ctinfo)
> > {
> > - enum nf_nat_manip_type maniptype;
> > - int err;
> > + int err, action = 0;
> >
> > if (!(info->nat & OVS_CT_NAT))
> > return NF_ACCEPT;
> > + if (info->nat & OVS_CT_SRC_NAT)
> > + action |= (1 << NF_NAT_MANIP_SRC);
> > + if (info->nat & OVS_CT_DST_NAT)
> > + action |= (1 << NF_NAT_MANIP_DST);
>
> I'm wondering why this dance at this level with supporting multiple
> MANIPs while actually only one can be used at a time.
>
> act_ct will reject an action using both:
> if ((p->ct_action & TCA_CT_ACT_NAT_SRC) &&
> (p->ct_action & TCA_CT_ACT_NAT_DST)) {
> NL_SET_ERR_MSG_MOD(extack, "dnat and snat can't be enabled at the same time");
> return -EOPNOTSUPP;
>
> I couldn't find this kind of check in ovs code right now (didn't look much, I
> confess :)), but even the code here was already doing:
>
> - } else if (info->nat & OVS_CT_SRC_NAT) {
> - maniptype = NF_NAT_MANIP_SRC;
> - } else if (info->nat & OVS_CT_DST_NAT) {
> - maniptype = NF_NAT_MANIP_DST;
>
> And in case of tuple conflict, maniptype will be forcibly updated in
> [*] below.
Ahh.. just found why.. in case of typle conflict, nf_ct_nat() now may
set both.
>
> Anyhow, if really needed, it would be nice to use BIT(NF_NAT_MANIP_..)
> instead.
But still this.
>
> >
> > - /* 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. */
> > + err = nf_ct_nat(skb, ct, ctinfo, &action, &info->range, info->commit);
> >
> > - /* Determine NAT type.
> > - * Check if the NAT type can be deduced from the tracked connection.
> > - * Make sure new expected connections (IP_CT_RELATED) are NATted only
> > - * when committing.
> > - */
> > - if (ctinfo != IP_CT_NEW && ct->status & IPS_NAT_MASK &&
> > - (ctinfo != IP_CT_RELATED || info->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 (info->nat & OVS_CT_SRC_NAT) {
> > - maniptype = NF_NAT_MANIP_SRC;
> > - } else if (info->nat & OVS_CT_DST_NAT) {
> > - maniptype = NF_NAT_MANIP_DST;
> > - } else {
> > - return NF_ACCEPT; /* Connection is not NATed. */
> > - }
> > - err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype, key);
> > -
> > - 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 = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range,
> > - maniptype, key);
> > - } else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
> > - err = ovs_ct_nat_execute(skb, ct, ctinfo, NULL,
> > - NF_NAT_MANIP_SRC, key);
> > - }
> > - }
> > + if (action & (1 << NF_NAT_MANIP_SRC))
> > + ovs_nat_update_key(key, skb, NF_NAT_MANIP_SRC);
> > + if (action & (1 << NF_NAT_MANIP_DST))
> > + ovs_nat_update_key(key, skb, NF_NAT_MANIP_DST);
> >
> > return err;
> > }
> > diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
> > index c7782c9a6ab6..0c410220239f 100644
> > --- a/net/sched/act_ct.c
> > +++ b/net/sched/act_ct.c
> > @@ -863,90 +863,6 @@ static void tcf_ct_params_free_rcu(struct rcu_head *head)
> > tcf_ct_params_free(params);
> > }
> >
> > -#if IS_ENABLED(CONFIG_NF_NAT)
> > -/* 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 ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
> > - enum ip_conntrack_info ctinfo,
> > - 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);
> > -out:
> > - if (err == NF_ACCEPT) {
> > - if (maniptype == NF_NAT_MANIP_SRC)
> > - tc_skb_cb(skb)->post_ct_snat = 1;
> > - if (maniptype == NF_NAT_MANIP_DST)
> > - tc_skb_cb(skb)->post_ct_dnat = 1;
> > - }
> > - return err;
> > -}
> > -#endif /* CONFIG_NF_NAT */
> > -
> > static void tcf_ct_act_set_mark(struct nf_conn *ct, u32 mark, u32 mask)
> > {
> > #if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
> > @@ -986,52 +902,22 @@ static int tcf_ct_act_nat(struct sk_buff *skb,
> > bool commit)
> > {
> > #if IS_ENABLED(CONFIG_NF_NAT)
> > - int err;
> > - enum nf_nat_manip_type maniptype;
> > + int err, action = 0;
> >
> > if (!(ct_action & TCA_CT_ACT_NAT))
> > return NF_ACCEPT;
> > + if (ct_action & TCA_CT_ACT_NAT_SRC)
> > + action |= (1 << NF_NAT_MANIP_SRC);
> > + if (ct_action & TCA_CT_ACT_NAT_DST)
> > + action |= (1 << NF_NAT_MANIP_DST);
> >
> > - /* 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 & TCA_CT_ACT_NAT_SRC) {
> > - maniptype = NF_NAT_MANIP_SRC;
> > - } else if (ct_action & TCA_CT_ACT_NAT_DST) {
> > - maniptype = NF_NAT_MANIP_DST;
> > - } else {
> > - return NF_ACCEPT;
> > - }
> > + err = nf_ct_nat(skb, ct, ctinfo, &action, range, commit);
> > +
> > + if (action & (1 << NF_NAT_MANIP_SRC))
> > + tc_skb_cb(skb)->post_ct_snat = 1;
> > + if (action & (1 << NF_NAT_MANIP_DST))
> > + tc_skb_cb(skb)->post_ct_dnat = 1;
> >
> > - err = ct_nat_execute(skb, ct, ctinfo, 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 = ct_nat_execute(skb, ct, ctinfo, range,
> > - maniptype);
> > - } else if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) {
> > - err = ct_nat_execute(skb, ct, ctinfo, NULL,
> > - NF_NAT_MANIP_SRC);
> > - }
> > - }
> > return err;
> > #else
> > return NF_ACCEPT;
> > --
> > 2.31.1
> >
> _______________________________________________
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