Merge branch 'convert-config_ipv6-to-built-in-and-remove-stubs'

Fernando Fernandez Mancera says:

====================
Convert CONFIG_IPV6 to built-in and remove stubs

Historically, the Linux kernel has supported compiling the IPv6 stack as
a loadable module. While this made sense in the early days of IPv6
adoption, modern deployments and distributions overwhelmingly either
build IPv6 directly into the kernel (CONFIG_IPV6=y) or disable it
entirely (CONFIG_IPV6=n). The modular IPv6 use-case offers image size
and memory savings for specific setups, this benefit is outweighed by
the architectural burden it imposes on the subsystems on implementation
and maintenance.

In addition, most of the distributions are already using CONFIG_IPV6=y
by default [1], including openWRT [2] and Android gki_defconfig [3]. So
this won't have an impact on them. The most impacted architecture would
probably be arm64 as their default config is still using CONFIG_IPV6=m.

To allow core networking, BPF, Netfilter, and various device drivers to
safely interact with a potentially unloaded IPv6 module, the kernel
relies on indirect call structures like ipv6_stub, ipv6_bpf_stub, and
nf_ipv6_ops, along with dynamic RCU registrations for things like ICMPv6
senders.

This patch series addresses this by changing CONFIG_IPV6 from a tristate
to a boolean, enforcing that IPv6 is either built-in or disabled. This
allows us to completely rip out the stub infrastructures and safely
replace them with direct function calls.

The bloat-o-meter report the following results for m68k, arm64, x86_64
defconfig.

m68k (keep on mind that CONFIG_IPV6 is disabled now):
add/remove: 65/938 grow/shrink: 36/254 up/down: 3022/-49692 (-46670)

arm64:
add/remove: 1251/265 grow/shrink: 81/46 up/down: 448740/-71519 (377221)

x86_64:
add/remove: 62/98 grow/shrink: 10/39 up/down: 2497/-4357 (-1860)

Considering that each new kernel release increases sizes by 30-40KiB on
average, this size increase isn't a huge jump for the distributions that
are still using CONFIG_IPV6=m. For the ones that are already using
CONFIG_IPV6=y, the size is reduced actually.

All the patches has been independently build tested. With allmodconfig
and allmodconfig + CONFIG_IPV6=n. In addition, net selftest has been run
against them on virtme-ng.

The series applied as a whole as been tested with allyesconfig and also
allyesconfig + CONFIG_IPV6=n but not all patches has been independently
tested this way.

[1] https://github.com/nyrahul/linux-kernel-configs

[2] https://github.com/openwrt/openwrt/commit/832e7b817221d288df76b763ca12c585365db5d8

[3] https://android.googlesource.com/kernel/common/+/refs/heads/android-mainline/arch/arm64/configs/gki_defconfig
====================

Link: https://patch.msgid.link/20260325120928.15848-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

10 files changed, 88 insertions, 261 deletions

diff --git a/include/linux/icmpv6.h b/include/linux/icmpv6.h
index e3b3b0fa2a8f..2bd9f2157e6c 100644
--- a/include/linux/icmpv6.h
+++ b/include/linux/icmpv6.h
@@ -15,38 +15,13 @@ static inline struct icmp6hdr *icmp6_hdr(const struct sk_buff *skb)
 
 #if IS_ENABLED(CONFIG_IPV6)
 
-typedef void ip6_icmp_send_t(struct sk_buff *skb, u8 type, u8 code, __u32 info,
-			     const struct in6_addr *force_saddr,
-			     const struct inet6_skb_parm *parm);
 void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
 		const struct in6_addr *force_saddr,
 		const struct inet6_skb_parm *parm);
-#if IS_BUILTIN(CONFIG_IPV6)
-static inline void __icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
-				 const struct inet6_skb_parm *parm)
-{
-	icmp6_send(skb, type, code, info, NULL, parm);
-}
-static inline int inet6_register_icmp_sender(ip6_icmp_send_t *fn)
-{
-	BUILD_BUG_ON(fn != icmp6_send);
-	return 0;
-}
-static inline int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn)
-{
-	BUILD_BUG_ON(fn != icmp6_send);
-	return 0;
-}
-#else
-extern void __icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
-			  const struct inet6_skb_parm *parm);
-extern int inet6_register_icmp_sender(ip6_icmp_send_t *fn);
-extern int inet6_unregister_icmp_sender(ip6_icmp_send_t *fn);
-#endif
 
 static inline void icmpv6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info)
 {
-	__icmpv6_send(skb, type, code, info, IP6CB(skb));
+	icmp6_send(skb, type, code, info, NULL, IP6CB(skb));
 }
 
 int ip6_err_gen_icmpv6_unreach(struct sk_buff *skb, int nhs, int type,
@@ -58,7 +33,7 @@ void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info);
 static inline void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info)
 {
 	struct inet6_skb_parm parm = { 0 };
-	__icmpv6_send(skb_in, type, code, info, &parm);
+	icmp6_send(skb_in, type, code, info, NULL, &parm);
 }
 #endif
 
diff --git a/include/linux/indirect_call_wrapper.h b/include/linux/indirect_call_wrapper.h
index dc272b514a01..0e4340ecd857 100644
--- a/include/linux/indirect_call_wrapper.h
+++ b/include/linux/indirect_call_wrapper.h
@@ -57,7 +57,7 @@
  * builtin, this macro simplify dealing with indirect calls with only ipv4/ipv6
  * alternatives
  */
-#if IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6)
 #define INDIRECT_CALL_INET(f, f2, f1, ...) \
 	INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
 #elif IS_ENABLED(CONFIG_INET)
diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h
index 61aa48f46dd7..5ce45b6d890f 100644
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -34,59 +34,13 @@ struct ip6_rt_info {
 struct nf_queue_entry;
 struct nf_bridge_frag_data;
 
-/*
- * Hook functions for ipv6 to allow xt_* modules to be built-in even
- * if IPv6 is a module.
- */
-struct nf_ipv6_ops {
-#if IS_MODULE(CONFIG_IPV6)
-	int (*chk_addr)(struct net *net, const struct in6_addr *addr,
-			const struct net_device *dev, int strict);
-	int (*route_me_harder)(struct net *net, struct sock *sk, struct sk_buff *skb);
-	int (*dev_get_saddr)(struct net *net, const struct net_device *dev,
-		       const struct in6_addr *daddr, unsigned int srcprefs,
-		       struct in6_addr *saddr);
-	int (*route)(struct net *net, struct dst_entry **dst, struct flowi *fl,
-		     bool strict);
-	u32 (*cookie_init_sequence)(const struct ipv6hdr *iph,
-				    const struct tcphdr *th, u16 *mssp);
-	int (*cookie_v6_check)(const struct ipv6hdr *iph,
-			       const struct tcphdr *th);
-#endif
-	void (*route_input)(struct sk_buff *skb);
-	int (*fragment)(struct net *net, struct sock *sk, struct sk_buff *skb,
-			int (*output)(struct net *, struct sock *, struct sk_buff *));
-	int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
-#if IS_MODULE(CONFIG_IPV6)
-	int (*br_fragment)(struct net *net, struct sock *sk,
-			   struct sk_buff *skb,
-			   struct nf_bridge_frag_data *data,
-			   int (*output)(struct net *, struct sock *sk,
-					 const struct nf_bridge_frag_data *data,
-					 struct sk_buff *));
-#endif
-};
-
 #ifdef CONFIG_NETFILTER
 #include <net/addrconf.h>
 
-extern const struct nf_ipv6_ops __rcu *nf_ipv6_ops;
-static inline const struct nf_ipv6_ops *nf_get_ipv6_ops(void)
-{
-	return rcu_dereference(nf_ipv6_ops);
-}
-
 static inline int nf_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
 				   const struct net_device *dev, int strict)
 {
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
-	if (!v6_ops)
-		return 1;
-
-	return v6_ops->chk_addr(net, addr, dev, strict);
-#elif IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6)
 	return ipv6_chk_addr(net, addr, dev, strict);
 #else
 	return 1;
@@ -99,15 +53,7 @@ int __nf_ip6_route(struct net *net, struct dst_entry **dst,
 static inline int nf_ip6_route(struct net *net, struct dst_entry **dst,
 			       struct flowi *fl, bool strict)
 {
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6ops = nf_get_ipv6_ops();
-
-	if (v6ops)
-		return v6ops->route(net, dst, fl, strict);
-
-	return -EHOSTUNREACH;
-#endif
-#if IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6)
 	return __nf_ip6_route(net, dst, fl, strict);
 #else
 	return -EHOSTUNREACH;
@@ -129,14 +75,7 @@ static inline int nf_br_ip6_fragment(struct net *net, struct sock *sk,
 						   const struct nf_bridge_frag_data *data,
 						   struct sk_buff *))
 {
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
-	if (!v6_ops)
-		return 1;
-
-	return v6_ops->br_fragment(net, sk, skb, data, output);
-#elif IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6)
 	return br_ip6_fragment(net, sk, skb, data, output);
 #else
 	return 1;
@@ -147,14 +86,7 @@ int ip6_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb);
 
 static inline int nf_ip6_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
-	if (!v6_ops)
-		return -EHOSTUNREACH;
-
-	return v6_ops->route_me_harder(net, sk, skb);
-#elif IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6)
 	return ip6_route_me_harder(net, sk, skb);
 #else
 	return -EHOSTUNREACH;
@@ -165,32 +97,18 @@ static inline u32 nf_ipv6_cookie_init_sequence(const struct ipv6hdr *iph,
 					       const struct tcphdr *th,
 					       u16 *mssp)
 {
-#if IS_ENABLED(CONFIG_SYN_COOKIES)
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
-	if (v6_ops)
-		return v6_ops->cookie_init_sequence(iph, th, mssp);
-#elif IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6) && IS_ENABLED(CONFIG_SYN_COOKIES)
 	return __cookie_v6_init_sequence(iph, th, mssp);
 #endif
-#endif
 	return 0;
 }
 
 static inline int nf_cookie_v6_check(const struct ipv6hdr *iph,
 				     const struct tcphdr *th)
 {
-#if IS_ENABLED(CONFIG_SYN_COOKIES)
-#if IS_MODULE(CONFIG_IPV6)
-	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
-
-	if (v6_ops)
-		return v6_ops->cookie_v6_check(iph, th);
-#elif IS_BUILTIN(CONFIG_IPV6)
+#if IS_ENABLED(CONFIG_IPV6) && IS_ENABLED(CONFIG_SYN_COOKIES)
 	return __cookie_v6_check(iph, th);
 #endif
-#endif
 	return 0;
 }
 
@@ -198,14 +116,6 @@ __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
 			unsigned int dataoff, u_int8_t protocol);
 
 int nf_ip6_check_hbh_len(struct sk_buff *skb, u32 *plen);
-
-int ipv6_netfilter_init(void);
-void ipv6_netfilter_fini(void);
-
-#else /* CONFIG_NETFILTER */
-static inline int ipv6_netfilter_init(void) { return 0; }
-static inline void ipv6_netfilter_fini(void) { return; }
-static inline const struct nf_ipv6_ops *nf_get_ipv6_ops(void) { return NULL; }
 #endif /* CONFIG_NETFILTER */
 
 #endif /*__LINUX_IP6_NETFILTER_H*/
diff --git a/include/net/ip.h b/include/net/ip.h
index f39a3787fedd..7f2fe1a8401b 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -692,14 +692,6 @@ static __inline__ void inet_reset_saddr(struct sock *sk)
 
 #endif
 
-#if IS_MODULE(CONFIG_IPV6)
-#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X)
-#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X)
-#else
-#define EXPORT_IPV6_MOD(X)
-#define EXPORT_IPV6_MOD_GPL(X)
-#endif
-
 static inline unsigned int ipv4_addr_hash(__be32 ip)
 {
 	return (__force unsigned int) ip;
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 9f8b6814a96a..9cd27e1b9b69 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -486,11 +486,30 @@ void rt6_get_prefsrc(const struct rt6_info *rt, struct in6_addr *addr)
 	rcu_read_unlock();
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
 int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 		 struct fib6_config *cfg, gfp_t gfp_flags,
 		 struct netlink_ext_ack *extack);
 void fib6_nh_release(struct fib6_nh *fib6_nh);
 void fib6_nh_release_dsts(struct fib6_nh *fib6_nh);
+#else
+static inline int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
+			       struct fib6_config *cfg, gfp_t gfp_flags,
+			       struct netlink_ext_ack *extack)
+{
+	NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel");
+	return -EAFNOSUPPORT;
+}
+
+static inline void fib6_nh_release(struct fib6_nh *fib6_nh)
+{
+}
+
+static inline void fib6_nh_release_dsts(struct fib6_nh *fib6_nh)
+{
+}
+#endif
+
 
 int call_fib6_entry_notifiers(struct net *net,
 			      enum fib_event_type event_type,
@@ -502,8 +521,15 @@ int call_fib6_multipath_entry_notifiers(struct net *net,
 					unsigned int nsiblings,
 					struct netlink_ext_ack *extack);
 int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt);
+#if IS_ENABLED(CONFIG_IPV6)
 void fib6_rt_update(struct net *net, struct fib6_info *rt,
 		    struct nl_info *info);
+#else
+static inline void fib6_rt_update(struct net *net, struct fib6_info *rt,
+				  struct nl_info *info)
+{
+}
+#endif
 void inet6_rt_notify(int event, struct fib6_info *rt, struct nl_info *info,
 		     unsigned int flags);
 
@@ -588,8 +614,13 @@ int fib6_tables_dump(struct net *net, struct notifier_block *nb,
 		     struct netlink_ext_ack *extack);
 
 void fib6_update_sernum(struct net *net, struct fib6_info *rt);
+#if IS_ENABLED(CONFIG_IPV6)
 void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt);
-void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
+#else
+static inline void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
+{
+}
+#endif
 
 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
@@ -599,7 +630,7 @@ static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
 void fib6_info_hw_flags_set(struct net *net, struct fib6_info *f6i,
 			    bool offload, bool trap, bool offload_failed);
 
-#if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
+#if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
 struct bpf_iter__ipv6_route {
 	__bpf_md_ptr(struct bpf_iter_meta *, meta);
 	__bpf_md_ptr(struct fib6_info *, rt);
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 0c8eeb6abe7a..09ffe0f13ce7 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -77,7 +77,14 @@ static inline bool rt6_qualify_for_ecmp(const struct fib6_info *f6i)
 		f6i->fib6_nh->fib_nh_gw_family;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
 void ip6_route_input(struct sk_buff *skb);
+#else
+static inline void ip6_route_input(struct sk_buff *skb)
+{
+}
+#endif
+
 struct dst_entry *ip6_route_input_lookup(struct net *net,
 					 struct net_device *dev,
 					 struct flowi6 *fl6,
@@ -119,7 +126,15 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd,
 int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
 		  struct netlink_ext_ack *extack);
 int ip6_ins_rt(struct net *net, struct fib6_info *f6i);
+#if IS_ENABLED(CONFIG_IPV6)
 int ip6_del_rt(struct net *net, struct fib6_info *f6i, bool skip_notify);
+#else
+static inline int ip6_del_rt(struct net *net, struct fib6_info *f6i,
+			     bool skip_notify)
+{
+	return -EAFNOSUPPORT;
+}
+#endif
 
 void rt6_flush_exceptions(struct fib6_info *f6i);
 void rt6_age_exceptions(struct fib6_info *f6i, struct fib6_gc_args *gc_args,
@@ -270,8 +285,19 @@ static inline bool ipv6_anycast_destination(const struct dst_entry *dst,
 	return __ipv6_anycast_destination(&rt->rt6i_dst, rt->rt6i_flags, daddr);
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
 int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
 		 int (*output)(struct net *, struct sock *, struct sk_buff *));
+#else
+static inline int ip6_fragment(struct net *net, struct sock *sk,
+			       struct sk_buff *skb,
+			       int (*output)(struct net *, struct sock *,
+					     struct sk_buff *))
+{
+	kfree_skb(skb);
+	return -EAFNOSUPPORT;
+}
+#endif
 
 /* Variant of dst_mtu() for IPv6 users */
 static inline u32 dst6_mtu(const struct dst_entry *dst)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 0958cc5c6ec3..d042afe7a245 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1044,8 +1044,18 @@ static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
 
 int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
 		   struct flowi6 *fl6);
+#if IS_ENABLED(CONFIG_IPV6)
 struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, struct flowi6 *fl6,
 				      const struct in6_addr *final_dst);
+#else
+static inline struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk,
+						    struct flowi6 *fl6,
+						    const struct in6_addr *final_dst)
+{
+	return ERR_PTR(-EAFNOSUPPORT);
+}
+#endif
+
 struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
 					 const struct in6_addr *final_dst,
 					 bool connected);
@@ -1139,6 +1149,8 @@ void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu);
 void inet6_cleanup_sock(struct sock *sk);
 void inet6_sock_destruct(struct sock *sk);
 int inet6_release(struct socket *sock);
+int __inet6_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len,
+		 u32 flags);
 int inet6_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len);
 int inet6_bind_sk(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
 int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
deleted file mode 100644
index 907681cecde8..000000000000
--- a/include/net/ipv6_stubs.h
+++ /dev/null
@@ -1,101 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _IPV6_STUBS_H
-#define _IPV6_STUBS_H
-
-#include <linux/in6.h>
-#include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <net/dst.h>
-#include <net/flow.h>
-#include <net/neighbour.h>
-#include <net/sock.h>
-#include <net/ipv6.h>
-
-/* structs from net/ip6_fib.h */
-struct fib6_info;
-struct fib6_nh;
-struct fib6_config;
-struct fib6_result;
-
-/* This is ugly, ideally these symbols should be built
- * into the core kernel.
- */
-struct ipv6_stub {
-	int (*ipv6_sock_mc_join)(struct sock *sk, int ifindex,
-				 const struct in6_addr *addr);
-	int (*ipv6_sock_mc_drop)(struct sock *sk, int ifindex,
-				 const struct in6_addr *addr);
-	struct dst_entry *(*ipv6_dst_lookup_flow)(struct net *net,
-						  const struct sock *sk,
-						  struct flowi6 *fl6,
-						  const struct in6_addr *final_dst);
-	int (*ipv6_route_input)(struct sk_buff *skb);
-
-	struct fib6_table *(*fib6_get_table)(struct net *net, u32 id);
-	int (*fib6_lookup)(struct net *net, int oif, struct flowi6 *fl6,
-			   struct fib6_result *res, int flags);
-	int (*fib6_table_lookup)(struct net *net, struct fib6_table *table,
-				 int oif, struct flowi6 *fl6,
-				 struct fib6_result *res, int flags);
-	void (*fib6_select_path)(const struct net *net, struct fib6_result *res,
-				 struct flowi6 *fl6, int oif, bool oif_match,
-				 const struct sk_buff *skb, int strict);
-	u32 (*ip6_mtu_from_fib6)(const struct fib6_result *res,
-				 const struct in6_addr *daddr,
-				 const struct in6_addr *saddr);
-
-	int (*fib6_nh_init)(struct net *net, struct fib6_nh *fib6_nh,
-			    struct fib6_config *cfg, gfp_t gfp_flags,
-			    struct netlink_ext_ack *extack);
-	void (*fib6_nh_release)(struct fib6_nh *fib6_nh);
-	void (*fib6_nh_release_dsts)(struct fib6_nh *fib6_nh);
-	void (*fib6_update_sernum)(struct net *net, struct fib6_info *rt);
-	int (*ip6_del_rt)(struct net *net, struct fib6_info *rt, bool skip_notify);
-	void (*fib6_rt_update)(struct net *net, struct fib6_info *rt,
-			       struct nl_info *info);
-
-	void (*udpv6_encap_enable)(void);
-	void (*ndisc_send_na)(struct net_device *dev, const struct in6_addr *daddr,
-			      const struct in6_addr *solicited_addr,
-			      bool router, bool solicited, bool override, bool inc_opt);
-#if IS_ENABLED(CONFIG_XFRM)
-	void (*xfrm6_local_rxpmtu)(struct sk_buff *skb, u32 mtu);
-	int (*xfrm6_udp_encap_rcv)(struct sock *sk, struct sk_buff *skb);
-	struct sk_buff *(*xfrm6_gro_udp_encap_rcv)(struct sock *sk,
-						   struct list_head *head,
-						   struct sk_buff *skb);
-	int (*xfrm6_rcv_encap)(struct sk_buff *skb, int nexthdr, __be32 spi,
-			       int encap_type);
-#endif
-	struct neigh_table *nd_tbl;
-
-	int (*ipv6_fragment)(struct net *net, struct sock *sk, struct sk_buff *skb,
-			     int (*output)(struct net *, struct sock *, struct sk_buff *));
-	struct net_device *(*ipv6_dev_find)(struct net *net, const struct in6_addr *addr,
-					    struct net_device *dev);
-	int (*ip6_xmit)(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
-			__u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority);
-};
-extern const struct ipv6_stub *ipv6_stub __read_mostly;
-
-/* A stub used by bpf helpers. Similarly ugly as ipv6_stub */
-struct ipv6_bpf_stub {
-	int (*inet6_bind)(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len,
-			  u32 flags);
-	struct sock *(*udp6_lib_lookup)(const struct net *net,
-					const struct in6_addr *saddr, __be16 sport,
-					const struct in6_addr *daddr, __be16 dport,
-					int dif, int sdif, struct sk_buff *skb);
-	int (*ipv6_setsockopt)(struct sock *sk, int level, int optname,
-			       sockptr_t optval, unsigned int optlen);
-	int (*ipv6_getsockopt)(struct sock *sk, int level, int optname,
-			       sockptr_t optval, sockptr_t optlen);
-	int (*ipv6_dev_get_saddr)(struct net *net,
-				  const struct net_device *dst_dev,
-				  const struct in6_addr *daddr,
-				  unsigned int prefs,
-				  struct in6_addr *saddr);
-};
-extern const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly;
-
-#endif
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index d38783a2ce57..3da1a6f8d3f9 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -2,8 +2,6 @@
 #ifndef _NDISC_H
 #define _NDISC_H
 
-#include <net/ipv6_stubs.h>
-
 /*
  *	ICMP codes for neighbour discovery messages
  */
@@ -359,14 +357,6 @@ static inline struct neighbour *__ipv6_neigh_lookup_noref(struct net_device *dev
 	return ___neigh_lookup_noref(&nd_tbl, neigh_key_eq128, ndisc_hashfn, pkey, dev);
 }
 
-static inline
-struct neighbour *__ipv6_neigh_lookup_noref_stub(struct net_device *dev,
-						 const void *pkey)
-{
-	return ___neigh_lookup_noref(ipv6_stub->nd_tbl, neigh_key_eq128,
-				     ndisc_hashfn, pkey, dev);
-}
-
 static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, const void *pkey)
 {
 	struct neighbour *n;
@@ -391,28 +381,20 @@ static inline void __ipv6_confirm_neigh(struct net_device *dev,
 	rcu_read_unlock();
 }
 
-static inline void __ipv6_confirm_neigh_stub(struct net_device *dev,
-					     const void *pkey)
-{
-	struct neighbour *n;
-
-	rcu_read_lock();
-	n = __ipv6_neigh_lookup_noref_stub(dev, pkey);
-	neigh_confirm(n);
-	rcu_read_unlock();
-}
-
-/* uses ipv6_stub and is meant for use outside of IPv6 core */
 static inline struct neighbour *ip_neigh_gw6(struct net_device *dev,
 					     const void *addr)
 {
+#if IS_ENABLED(CONFIG_IPV6)
 	struct neighbour *neigh;
 
-	neigh = __ipv6_neigh_lookup_noref_stub(dev, addr);
+	neigh = __ipv6_neigh_lookup_noref(dev, addr);
 	if (unlikely(!neigh))
-		neigh = __neigh_create(ipv6_stub->nd_tbl, addr, dev, false);
+		neigh = __neigh_create(&nd_tbl, addr, dev, false);
 
 	return neigh;
+#else
+	return ERR_PTR(-EAFNOSUPPORT);
+#endif
 }
 
 int ndisc_init(void);
@@ -434,6 +416,7 @@ void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr,
 
 void ndisc_send_rs(struct net_device *dev,
 		   const struct in6_addr *saddr, const struct in6_addr *daddr);
+
 void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
 		   const struct in6_addr *solicited_addr,
 		   bool router, bool solicited, bool override, bool inc_opt);
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index fc1fc43345b5..47c23d4a1740 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -7,7 +7,6 @@
 
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6.h>
-#include <net/ipv6_stubs.h>
 #endif
 
 #define UDP_TUNNEL_PARTIAL_FEATURES	NETIF_F_GSO_ENCAP_ALL
@@ -230,7 +229,7 @@ static inline void udp_tunnel_encap_enable(struct sock *sk)
 
 #if IS_ENABLED(CONFIG_IPV6)
 	if (READ_ONCE(sk->sk_family) == PF_INET6)
-		ipv6_stub->udpv6_encap_enable();
+		udpv6_encap_enable();
 #endif
 	udp_encap_enable();
 }