From: Fernando Fernandez Mancera Date: Wed, 25 Mar 2026 12:08:46 +0000 (+0100) Subject: ipv6: prepare headers for ipv6_stub removal X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4b70b20215049472f200ed563a7a0d44a7188fd3;p=thirdparty%2Fkernel%2Flinux.git ipv6: prepare headers for ipv6_stub removal In preparation for dropping ipv6_stub and converting its users to direct function calls, introduce static inline dummy functions and fallback macros in the IPv6 networking headers. In addition, introduce checks on fib6_nh_init(), ip6_dst_lookup_flow() and ip6_fragment() to avoid a crash due to ipv6.disable=1 set during booting. The other functions are safe as they cannot be called with ipv6.disable=1 set. These fallbacks ensure that when CONFIG_IPV6 is completely disabled, there are no compiling or linking errors due to code paths not guarded by preprocessor macro IS_ENABLED(CONFIG_IPV6). In addition, export ndisc_send_na(), ip6_route_input() and ip6_fragment(). Signed-off-by: Fernando Fernandez Mancera Tested-by: Ricardo B. Marlière Link: https://patch.msgid.link/20260325120928.15848-6-fmancera@suse.de Signed-off-by: Jakub Kicinski --- diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 10f30d158340..20e1231262d6 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); @@ -588,7 +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); +#else +static inline void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt) +{ +} +#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); 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..f99f273341f0 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); diff --git a/include/net/ndisc.h b/include/net/ndisc.h index d38783a2ce57..19e2a177bd29 100644 --- a/include/net/ndisc.h +++ b/include/net/ndisc.h @@ -406,13 +406,17 @@ static inline void __ipv6_confirm_neigh_stub(struct net_device *dev, 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); 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); diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 8e2a6b28cea7..63abc4fddaee 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -873,6 +873,11 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, __be32 frag_id; u8 *prevhdr, nexthdr = 0; + if (!ipv6_mod_enabled()) { + kfree_skb(skb); + return -EAFNOSUPPORT; + } + err = ip6_find_1stfragopt(skb, &prevhdr); if (err < 0) goto fail; @@ -1045,6 +1050,7 @@ fail: kfree_skb(skb); return err; } +EXPORT_SYMBOL_GPL(ip6_fragment); static inline int ip6_rt_check(const struct rt6key *rt_key, const struct in6_addr *fl_addr, @@ -1256,6 +1262,8 @@ struct dst_entry *ip6_dst_lookup_flow(struct net *net, const struct sock *sk, st struct dst_entry *dst = NULL; int err; + if (!ipv6_mod_enabled()) + return ERR_PTR(-EAFNOSUPPORT); err = ip6_dst_lookup_tail(net, sk, &dst, fl6); if (err) return ERR_PTR(err); diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index f6a5d8c73af9..f76fb8a85452 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -576,6 +576,7 @@ void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr, ndisc_send_skb(skb, daddr, src_addr); } +EXPORT_SYMBOL_GPL(ndisc_send_na); static void ndisc_send_unsol_na(struct net_device *dev) { diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 08deb18dcc85..19eb6b702227 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2655,6 +2655,7 @@ void ip6_route_input(struct sk_buff *skb) skb_dst_set_noref(skb, ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags)); } +EXPORT_SYMBOL_GPL(ip6_route_input); INDIRECT_CALLABLE_SCOPE struct rt6_info *ip6_pol_route_output(struct net *net, struct fib6_table *table, @@ -3585,6 +3586,11 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh, struct inet6_dev *idev = NULL; int err; + if (!ipv6_mod_enabled()) { + NL_SET_ERR_MSG(extack, "IPv6 support not enabled in kernel"); + return -EAFNOSUPPORT; + } + fib6_nh->fib_nh_family = AF_INET6; #ifdef CONFIG_IPV6_ROUTER_PREF fib6_nh->last_probe = jiffies;