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Date: Wed, 16 Nov 2022 16:05:44 -0500
From: Aaron Conole <aconole@...hat.com>
To: Xin Long <lucien.xin@...il.com>
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>,
Pablo Neira Ayuso <pablo@...filter.org>,
Florian Westphal <fw@...len.de>,
Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
Davide Caratti <dcaratti@...hat.com>,
Eelco Chaudron <echaudro@...hat.com>
Subject: Re: [PATCH net-next 5/5] net: move the nat function to nf_nat_core
for ovs and tc
Hi Xin,
Xin Long <lucien.xin@...il.com> writes:
> There are two nat functions are nearly the same in both OVS and
> TC code, (ovs_)ct_nat_execute() and ovs_ct_nat/tcf_ct_act_nat().
>
> This patch is to move them to netfilter nf_nat_core and export
> nf_ct_nat() so that it can be shared by both OVS and TC, and
> keep the nat (type) check and nat flag update in OVS and TC's
> own place, as these parts are different between OVS and TC.
>
> Note that in OVS nat function it was using skb->protocol to get
> the proto as it already skips vlans in key_extract(), while it
> doesn't in TC, and TC has to call skb_protocol() to get proto.
> So in nf_ct_nat_execute(), we keep using skb_protocol() which
> works for both OVS and TC.
>
> Signed-off-by: Xin Long <lucien.xin@...il.com>
> ---
> include/net/netfilter/nf_nat.h | 4 +
> net/netfilter/nf_nat_core.c | 131 +++++++++++++++++++++++++++++++
> net/openvswitch/conntrack.c | 137 +++------------------------------
> net/sched/act_ct.c | 136 +++-----------------------------
> 4 files changed, 156 insertions(+), 252 deletions(-)
>
> diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
> index e9eb01e99d2f..9877f064548a 100644
> --- a/include/net/netfilter/nf_nat.h
> +++ b/include/net/netfilter/nf_nat.h
> @@ -104,6 +104,10 @@ unsigned int
> nf_nat_inet_fn(void *priv, struct sk_buff *skb,
> const struct nf_hook_state *state);
>
> +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);
> +
> static inline int nf_nat_initialized(const struct nf_conn *ct,
> enum nf_nat_manip_type manip)
> {
> 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);
> +
> struct nf_nat_proto_clean {
> u8 l3proto;
> u8 l4proto;
> 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);
>
> - /* 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);
I haven't tested this yet with tuple collision, but if I'm reading the
code right, info->nat will only be from the parsed actions (which will
have a single src/dst manipulation). But, this code was previously
always updated based on ct->status information, which isn't quite the
same. Maybe I'm missing something. I plan to run this testing
tomorrow, but maybe you have already tested for it?
> 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;
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