[PATCH 10/11 net-next v5] ipv6: remove ipv6_stub infrastructure completely

[Fernando Fernandez Mancera <fmancera@suse.de>]

As IPv6 is built-in only and there are no more users of ipv6_stub, the
ipv6_stub is now entirely obsolete.

Remove all the code related to the definition, initialization and usage.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Tested-by: Ricardo B. Marlière <rbm@suse.com>
---
 include/net/ip6_fib.h     |  1 -
 include/net/ipv6_stubs.h  | 80 ----------------------------------
 include/net/ndisc.h       | 25 +----------
 include/net/udp_tunnel.h  |  1 -
 net/ipv6/addrconf_core.c  | 91 ---------------------------------------
 net/ipv6/af_inet6.c       | 40 -----------------
 net/ipv6/ip6_fib.c        |  8 ----
 net/ipv6/ip6_udp_tunnel.c |  3 +-
 8 files changed, 3 insertions(+), 246 deletions(-)
 delete mode 100644 include/net/ipv6_stubs.h

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index f01ef8ffe296..3e72cce4fe0f 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -602,7 +602,6 @@ static inline void fib6_update_sernum_upto_root(struct net *net, struct fib6_inf
 {
 }
 #endif
-void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i);
 
 void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val);
 static inline bool fib6_metric_locked(struct fib6_info *f6i, int metric)
diff --git a/include/net/ipv6_stubs.h b/include/net/ipv6_stubs.h
deleted file mode 100644
index dc708d9eca7a..000000000000
--- a/include/net/ipv6_stubs.h
+++ /dev/null
@@ -1,80 +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;
-#endif
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 19e2a177bd29..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;
@@ -391,25 +381,13 @@ 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(&nd_tbl, addr, dev, false);
 
@@ -438,6 +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 40089fc4c1ba..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
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index c008d21925d7..fa27a90ab3cd 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -6,7 +6,6 @@
 
 #include <linux/export.h>
 #include <net/ipv6.h>
-#include <net/ipv6_stubs.h>
 #include <net/addrconf.h>
 #include <net/ip.h>
 
@@ -129,96 +128,6 @@ int inet6addr_validator_notifier_call_chain(unsigned long val, void *v)
 }
 EXPORT_SYMBOL(inet6addr_validator_notifier_call_chain);
 
-static struct dst_entry *eafnosupport_ipv6_dst_lookup_flow(struct net *net,
-							   const struct sock *sk,
-							   struct flowi6 *fl6,
-							   const struct in6_addr *final_dst)
-{
-	return ERR_PTR(-EAFNOSUPPORT);
-}
-
-static int eafnosupport_ipv6_route_input(struct sk_buff *skb)
-{
-	return -EAFNOSUPPORT;
-}
-
-static struct fib6_table *eafnosupport_fib6_get_table(struct net *net, u32 id)
-{
-	return NULL;
-}
-
-static int
-eafnosupport_fib6_table_lookup(struct net *net, struct fib6_table *table,
-			       int oif, struct flowi6 *fl6,
-			       struct fib6_result *res, int flags)
-{
-	return -EAFNOSUPPORT;
-}
-
-static int
-eafnosupport_fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
-			 struct fib6_result *res, int flags)
-{
-	return -EAFNOSUPPORT;
-}
-
-static void
-eafnosupport_fib6_select_path(const struct net *net, struct fib6_result *res,
-			      struct flowi6 *fl6, int oif, bool have_oif_match,
-			      const struct sk_buff *skb, int strict)
-{
-}
-
-static u32
-eafnosupport_ip6_mtu_from_fib6(const struct fib6_result *res,
-			       const struct in6_addr *daddr,
-			       const struct in6_addr *saddr)
-{
-	return 0;
-}
-
-static int eafnosupport_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 int eafnosupport_ip6_del_rt(struct net *net, struct fib6_info *rt,
-				   bool skip_notify)
-{
-	return -EAFNOSUPPORT;
-}
-
-static int eafnosupport_ipv6_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;
-}
-
-static struct net_device *eafnosupport_ipv6_dev_find(struct net *net, const struct in6_addr *addr,
-						     struct net_device *dev)
-{
-	return ERR_PTR(-EAFNOSUPPORT);
-}
-
-const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) {
-	.ipv6_dst_lookup_flow = eafnosupport_ipv6_dst_lookup_flow,
-	.ipv6_route_input  = eafnosupport_ipv6_route_input,
-	.fib6_get_table    = eafnosupport_fib6_get_table,
-	.fib6_table_lookup = eafnosupport_fib6_table_lookup,
-	.fib6_lookup       = eafnosupport_fib6_lookup,
-	.fib6_select_path  = eafnosupport_fib6_select_path,
-	.ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6,
-	.fib6_nh_init	   = eafnosupport_fib6_nh_init,
-	.ip6_del_rt	   = eafnosupport_ip6_del_rt,
-	.ipv6_fragment	   = eafnosupport_ipv6_fragment,
-	.ipv6_dev_find     = eafnosupport_ipv6_dev_find,
-};
-EXPORT_SYMBOL_GPL(ipv6_stub);
-
 /* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
 const struct in6_addr in6addr_loopback __aligned(BITS_PER_LONG/8)
 	= IN6ADDR_LOOPBACK_INIT;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 07ae6ea7743a..33abd8d8cd7d 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -51,7 +51,6 @@
 #include <net/transp_v6.h>
 #include <net/ip6_route.h>
 #include <net/addrconf.h>
-#include <net/ipv6_stubs.h>
 #include <net/ndisc.h>
 #ifdef CONFIG_IPV6_TUNNEL
 #include <net/ip6_tunnel.h>
@@ -996,42 +995,6 @@ static struct pernet_operations inet6_net_ops = {
 	.exit = inet6_net_exit,
 };
 
-static int ipv6_route_input(struct sk_buff *skb)
-{
-	ip6_route_input(skb);
-	return skb_dst(skb)->error;
-}
-
-static const struct ipv6_stub ipv6_stub_impl = {
-	.ipv6_sock_mc_join = ipv6_sock_mc_join,
-	.ipv6_sock_mc_drop = ipv6_sock_mc_drop,
-	.ipv6_dst_lookup_flow = ip6_dst_lookup_flow,
-	.ipv6_route_input  = ipv6_route_input,
-	.fib6_get_table	   = fib6_get_table,
-	.fib6_table_lookup = fib6_table_lookup,
-	.fib6_lookup       = fib6_lookup,
-	.fib6_select_path  = fib6_select_path,
-	.ip6_mtu_from_fib6 = ip6_mtu_from_fib6,
-	.fib6_nh_init	   = fib6_nh_init,
-	.fib6_nh_release   = fib6_nh_release,
-	.fib6_nh_release_dsts = fib6_nh_release_dsts,
-	.fib6_update_sernum = fib6_update_sernum_stub,
-	.fib6_rt_update	   = fib6_rt_update,
-	.ip6_del_rt	   = ip6_del_rt,
-	.udpv6_encap_enable = udpv6_encap_enable,
-	.ndisc_send_na = ndisc_send_na,
-#if IS_ENABLED(CONFIG_XFRM)
-	.xfrm6_local_rxpmtu = xfrm6_local_rxpmtu,
-	.xfrm6_udp_encap_rcv = xfrm6_udp_encap_rcv,
-	.xfrm6_gro_udp_encap_rcv = xfrm6_gro_udp_encap_rcv,
-	.xfrm6_rcv_encap = xfrm6_rcv_encap,
-#endif
-	.nd_tbl	= &nd_tbl,
-	.ipv6_fragment = ip6_fragment,
-	.ipv6_dev_find = ipv6_dev_find,
-	.ip6_xmit = ip6_xmit,
-};
-
 static int __init inet6_init(void)
 {
 	struct list_head *r;
@@ -1188,9 +1151,6 @@ static int __init inet6_init(void)
 		goto sysctl_fail;
 #endif
 
-	/* ensure that ipv6 stubs are visible only after ipv6 is ready */
-	wmb();
-	ipv6_stub = &ipv6_stub_impl;
 out:
 	return err;
 
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index a935004ec9df..3d52044e0bdb 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1408,14 +1408,6 @@ void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
 	__fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
 }
 
-/* allow ipv4 to update sernum via ipv6_stub */
-void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
-{
-	spin_lock_bh(&f6i->fib6_table->tb6_lock);
-	fib6_update_sernum_upto_root(net, f6i);
-	spin_unlock_bh(&f6i->fib6_table->tb6_lock);
-}
-
 /*
  *	Add routing information to the routing tree.
  *	<destination addr>/<source addr>
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index cef3e0210744..405ef1cb8864 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -162,8 +162,7 @@ struct dst_entry *udp_tunnel6_dst_lookup(struct sk_buff *skb,
 	fl6.fl6_dport = dport;
 	fl6.flowlabel = ip6_make_flowinfo(dsfield, key->label);
 
-	dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6,
-					      NULL);
+	dst = ip6_dst_lookup_flow(net, sock->sk, &fl6, NULL);
 	if (IS_ERR(dst)) {
 		netdev_dbg(dev, "no route to %pI6\n", &fl6.daddr);
 		return ERR_PTR(-ENETUNREACH);
-- 
2.53.0