Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next

Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for net-next. This
includes one patch to update ovs and act_ct to use nf_ct_put() instead
of nf_conntrack_put().

1) Add netns_tracker to nfnetlink_log and masquerade, from Eric Dumazet.

2) Remove redundant rcu read-size lock in nf_tables packet path.

3) Replace BUG() by WARN_ON_ONCE() in nft_payload.

4) Consolidate rule verdict tracing.

5) Replace WARN_ON() by WARN_ON_ONCE() in nf_tables core.

6) Make counter support built-in in nf_tables.

7) Add new field to conntrack object to identify locally generated
   traffic, from Florian Westphal.

8) Prevent NAT from shadowing well-known ports, from Florian Westphal.

9) Merge nf_flow_table_{ipv4,ipv6} into nf_flow_table_inet, also from
   Florian.

10) Remove redundant pointer in nft_pipapo AVX2 support, from Colin Ian King.

11) Replace opencoded max() in conntrack, from Jiapeng Chong.

12) Update conntrack to use refcount_t API, from Florian Westphal.

13) Move ip_ct_attach indirection into the nf_ct_hook structure.

14) Constify several pointer object in the netfilter codebase,
    from Florian Westphal.

15) Tree-wide replacement of nf_conntrack_put() by nf_ct_put(), also
    from Florian.

16) Fix egress splat due to incorrect rcu notation, from Florian.

17) Move stateful fields of connlimit, last, quota, numgen and limit
    out of the expression data area.

18) Build a blob to represent the ruleset in nf_tables, this is a
    requirement of the new register tracking infrastructure.

19) Add NFT_REG32_NUM to define the maximum number of 32-bit registers.

20) Add register tracking infrastructure to skip redundant
    store-to-register operations, this includes support for payload,
    meta and bitwise expresssions.

* git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next: (32 commits)
  netfilter: nft_meta: cancel register tracking after meta update
  netfilter: nft_payload: cancel register tracking after payload update
  netfilter: nft_bitwise: track register operations
  netfilter: nft_meta: track register operations
  netfilter: nft_payload: track register operations
  netfilter: nf_tables: add register tracking infrastructure
  netfilter: nf_tables: add NFT_REG32_NUM
  netfilter: nf_tables: add rule blob layout
  netfilter: nft_limit: move stateful fields out of expression data
  netfilter: nft_limit: rename stateful structure
  netfilter: nft_numgen: move stateful fields out of expression data
  netfilter: nft_quota: move stateful fields out of expression data
  netfilter: nft_last: move stateful fields out of expression data
  netfilter: nft_connlimit: move stateful fields out of expression data
  netfilter: egress: avoid a lockdep splat
  net: prefer nf_ct_put instead of nf_conntrack_put
  netfilter: conntrack: avoid useless indirection during conntrack destruction
  netfilter: make function op structures const
  netfilter: core: move ip_ct_attach indirection to struct nf_ct_hook
  netfilter: conntrack: convert to refcount_t api
  ...
====================

Link: https://lore.kernel.org/r/20220109231640.104123-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/netfilter.h

@@ -381,13 +381,13 @@ struct nf_nat_hook {
 				  enum ip_conntrack_dir dir);
 };
 
-extern struct nf_nat_hook __rcu *nf_nat_hook;
+extern const struct nf_nat_hook __rcu *nf_nat_hook;
 
 static inline void
 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 {
 #if IS_ENABLED(CONFIG_NF_NAT)
-	struct nf_nat_hook *nat_hook;
+	const struct nf_nat_hook *nat_hook;
 
 	rcu_read_lock();
 	nat_hook = rcu_dereference(nf_nat_hook);
@@ -440,7 +440,6 @@ nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
 #include <linux/netfilter/nf_conntrack_zones_common.h>
 
-extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
 struct nf_conntrack_tuple;
 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
@@ -463,8 +462,9 @@ struct nf_ct_hook {
 	void (*destroy)(struct nf_conntrack *);
 	bool (*get_tuple_skb)(struct nf_conntrack_tuple *,
 			      const struct sk_buff *);
+	void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb);
 };
-extern struct nf_ct_hook __rcu *nf_ct_hook;
+extern const struct nf_ct_hook __rcu *nf_ct_hook;
 
 struct nlattr;
 
@@ -479,7 +479,7 @@ struct nfnl_ct_hook {
 	void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
 			   enum ip_conntrack_info ctinfo, s32 off);
 };
-extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
+extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook;
 
 /**
  * nf_skb_duplicated - TEE target has sent a packet

include/linux/netfilter/nf_conntrack_common.h

@@ -2,7 +2,7 @@
 #ifndef _NF_CONNTRACK_COMMON_H
 #define _NF_CONNTRACK_COMMON_H
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <uapi/linux/netfilter/nf_conntrack_common.h>
 
 struct ip_conntrack_stat {
@@ -25,19 +25,21 @@ struct ip_conntrack_stat {
 #define NFCT_PTRMASK	~(NFCT_INFOMASK)
 
 struct nf_conntrack {
-	atomic_t use;
+	refcount_t use;
 };
 
 void nf_conntrack_destroy(struct nf_conntrack *nfct);
+
+/* like nf_ct_put, but without module dependency on nf_conntrack */
 static inline void nf_conntrack_put(struct nf_conntrack *nfct)
 {
-	if (nfct && atomic_dec_and_test(&nfct->use))
+	if (nfct && refcount_dec_and_test(&nfct->use))
 		nf_conntrack_destroy(nfct);
 }
 static inline void nf_conntrack_get(struct nf_conntrack *nfct)
 {
 	if (nfct)
-		atomic_inc(&nfct->use);
+		refcount_inc(&nfct->use);
 }
 
 #endif /* _NF_CONNTRACK_COMMON_H */

include/linux/netfilter_netdev.h

@@ -94,7 +94,7 @@ static inline struct sk_buff *nf_hook_egress(struct sk_buff *skb, int *rc,
 		return skb;
 #endif
 
-	e = rcu_dereference(dev->nf_hooks_egress);
+	e = rcu_dereference_check(dev->nf_hooks_egress, rcu_read_lock_bh_held());
 	if (!e)
 		return skb;