[PATCH 08/10 net-next v3] bpf: remove ipv6_bpf_stub completely and use direct function calls
From: Fernando Fernandez Mancera
Date: Tue Mar 17 2026 - 10:14:01 EST
As IPv6 is built-in only, the ipv6_bpf_stub can be removed completely.
Convert all ipv6_bpf_stub usage to direct function calls instead. The
fallback functions introduced previously will prevent linkage errors
when CONFIG_IPV6 is disabled.
Signed-off-by: Fernando Fernandez Mancera <fmancera@xxxxxxx>
Tested-by: Ricardo B. Marlière <rbm@xxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
---
include/net/ipv6.h | 2 ++
include/net/ipv6_stubs.h | 21 ----------------
net/core/filter.c | 54 ++++++++++++++++------------------------
net/core/lwt_bpf.c | 10 +++++---
net/ipv6/af_inet6.c | 13 ++--------
5 files changed, 33 insertions(+), 67 deletions(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index f99f273341f0..d042afe7a245 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1149,6 +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
index 907681cecde8..dc708d9eca7a 100644
--- a/include/net/ipv6_stubs.h
+++ b/include/net/ipv6_stubs.h
@@ -77,25 +77,4 @@ struct ipv6_stub {
__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/net/core/filter.c b/net/core/filter.c
index c56821afaa0f..4b0c98f0d994 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -73,7 +73,6 @@
#include <net/seg6.h>
#include <net/seg6_local.h>
#include <net/lwtunnel.h>
-#include <net/ipv6_stubs.h>
#include <net/bpf_sk_storage.h>
#include <net/transp_v6.h>
#include <linux/btf_ids.h>
@@ -2279,7 +2278,7 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
.saddr = ip6h->saddr,
};
- dst = ipv6_stub->ipv6_dst_lookup_flow(net, NULL, &fl6, NULL);
+ dst = ip6_dst_lookup_flow(net, NULL, &fl6, NULL);
if (IS_ERR(dst))
goto out_drop;
@@ -5577,12 +5576,12 @@ static int sol_ipv6_sockopt(struct sock *sk, int optname,
}
if (getopt)
- return ipv6_bpf_stub->ipv6_getsockopt(sk, SOL_IPV6, optname,
- KERNEL_SOCKPTR(optval),
- KERNEL_SOCKPTR(optlen));
+ return do_ipv6_getsockopt(sk, SOL_IPV6, optname,
+ KERNEL_SOCKPTR(optval),
+ KERNEL_SOCKPTR(optlen));
- return ipv6_bpf_stub->ipv6_setsockopt(sk, SOL_IPV6, optname,
- KERNEL_SOCKPTR(optval), *optlen);
+ return do_ipv6_setsockopt(sk, SOL_IPV6, optname,
+ KERNEL_SOCKPTR(optval), *optlen);
}
static int __bpf_setsockopt(struct sock *sk, int level, int optname,
@@ -5981,9 +5980,6 @@ static const struct bpf_func_proto bpf_sock_ops_cb_flags_set_proto = {
.arg2_type = ARG_ANYTHING,
};
-const struct ipv6_bpf_stub *ipv6_bpf_stub __read_mostly;
-EXPORT_SYMBOL_GPL(ipv6_bpf_stub);
-
BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr,
int, addr_len)
{
@@ -6007,11 +6003,9 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr,
return err;
if (((struct sockaddr_in6 *)addr)->sin6_port == htons(0))
flags |= BIND_FORCE_ADDRESS_NO_PORT;
- /* ipv6_bpf_stub cannot be NULL, since it's called from
- * bpf_cgroup_inet6_connect hook and ipv6 is already loaded
- */
- return ipv6_bpf_stub->inet6_bind(sk, (struct sockaddr_unsized *)addr,
- addr_len, flags);
+
+ return __inet6_bind(sk, (struct sockaddr_unsized *)addr,
+ addr_len, flags);
#endif /* CONFIG_IPV6 */
}
#endif /* CONFIG_INET */
@@ -6222,7 +6216,7 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
neigh = __ipv4_neigh_lookup_noref(dev,
(__force u32)params->ipv4_dst);
else
- neigh = __ipv6_neigh_lookup_noref_stub(dev, params->ipv6_dst);
+ neigh = __ipv6_neigh_lookup_noref(dev, params->ipv6_dst);
if (!neigh || !(READ_ONCE(neigh->nud_state) & NUD_VALID))
return BPF_FIB_LKUP_RET_NO_NEIGH;
@@ -6290,12 +6284,11 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
params->tbid = 0;
}
- tb = ipv6_stub->fib6_get_table(net, tbid);
+ tb = fib6_get_table(net, tbid);
if (unlikely(!tb))
return BPF_FIB_LKUP_RET_NOT_FWDED;
- err = ipv6_stub->fib6_table_lookup(net, tb, oif, &fl6, &res,
- strict);
+ err = fib6_table_lookup(net, tb, oif, &fl6, &res, strict);
} else {
if (flags & BPF_FIB_LOOKUP_MARK)
fl6.flowi6_mark = params->mark;
@@ -6305,7 +6298,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
fl6.flowi6_tun_key.tun_id = 0;
fl6.flowi6_uid = sock_net_uid(net, NULL);
- err = ipv6_stub->fib6_lookup(net, oif, &fl6, &res, strict);
+ err = fib6_lookup(net, oif, &fl6, &res, strict);
}
if (unlikely(err || IS_ERR_OR_NULL(res.f6i) ||
@@ -6326,11 +6319,11 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
return BPF_FIB_LKUP_RET_NOT_FWDED;
}
- ipv6_stub->fib6_select_path(net, &res, &fl6, fl6.flowi6_oif,
- fl6.flowi6_oif != 0, NULL, strict);
+ fib6_select_path(net, &res, &fl6, fl6.flowi6_oif,
+ fl6.flowi6_oif != 0, NULL, strict);
if (check_mtu) {
- mtu = ipv6_stub->ip6_mtu_from_fib6(&res, dst, src);
+ mtu = ip6_mtu_from_fib6(&res, dst, src);
if (params->tot_len > mtu) {
params->mtu_result = mtu; /* union with tot_len */
return BPF_FIB_LKUP_RET_FRAG_NEEDED;
@@ -6351,9 +6344,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
if (res.f6i->fib6_prefsrc.plen) {
*src = res.f6i->fib6_prefsrc.addr;
} else {
- err = ipv6_bpf_stub->ipv6_dev_get_saddr(net, dev,
- &fl6.daddr, 0,
- src);
+ err = ipv6_dev_get_saddr(net, dev, &fl6.daddr, 0, src);
if (err)
return BPF_FIB_LKUP_RET_NO_SRC_ADDR;
}
@@ -6365,7 +6356,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
/* xdp and cls_bpf programs are run in RCU-bh so rcu_read_lock_bh is
* not needed here.
*/
- neigh = __ipv6_neigh_lookup_noref_stub(dev, dst);
+ neigh = __ipv6_neigh_lookup_noref(dev, dst);
if (!neigh || !(READ_ONCE(neigh->nud_state) & NUD_VALID))
return BPF_FIB_LKUP_RET_NO_NEIGH;
memcpy(params->dmac, neigh->ha, ETH_ALEN);
@@ -6900,11 +6891,10 @@ static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple,
src6, tuple->ipv6.sport,
dst6, ntohs(tuple->ipv6.dport),
dif, sdif, &refcounted);
- else if (likely(ipv6_bpf_stub))
- sk = ipv6_bpf_stub->udp6_lib_lookup(net,
- src6, tuple->ipv6.sport,
- dst6, tuple->ipv6.dport,
- dif, sdif, NULL);
+ else if (likely(ipv6_mod_enabled()))
+ sk = __udp6_lib_lookup(net, src6, tuple->ipv6.sport,
+ dst6, tuple->ipv6.dport,
+ dif, sdif, NULL);
#endif
}
diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 9f40be0c3e71..f71ef82a5f3d 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -13,7 +13,6 @@
#include <net/gre.h>
#include <net/ip.h>
#include <net/ip6_route.h>
-#include <net/ipv6_stubs.h>
struct bpf_lwt_prog {
struct bpf_prog *prog;
@@ -103,7 +102,12 @@ static int bpf_lwt_input_reroute(struct sk_buff *skb)
dev_put(dev);
} else if (skb->protocol == htons(ETH_P_IPV6)) {
skb_dst_drop(skb);
- err = ipv6_stub->ipv6_route_input(skb);
+ if (IS_ENABLED(CONFIG_IPV6)) {
+ ip6_route_input(skb);
+ err = skb_dst(skb)->error;
+ } else {
+ err = -EAFNOSUPPORT;
+ }
} else {
err = -EAFNOSUPPORT;
}
@@ -233,7 +237,7 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
fl6.daddr = iph6->daddr;
fl6.saddr = iph6->saddr;
- dst = ipv6_stub->ipv6_dst_lookup_flow(net, skb->sk, &fl6, NULL);
+ dst = ip6_dst_lookup_flow(net, skb->sk, &fl6, NULL);
if (IS_ERR(dst)) {
err = PTR_ERR(dst);
goto err;
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index bb29b29fdcfb..07ae6ea7743a 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -264,8 +264,8 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol,
goto out;
}
-static int __inet6_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len,
- u32 flags)
+int __inet6_bind(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len,
+ u32 flags)
{
struct sockaddr_in6 *addr = (struct sockaddr_in6 *)uaddr;
struct inet_sock *inet = inet_sk(sk);
@@ -1032,14 +1032,6 @@ static const struct ipv6_stub ipv6_stub_impl = {
.ip6_xmit = ip6_xmit,
};
-static const struct ipv6_bpf_stub ipv6_bpf_stub_impl = {
- .inet6_bind = __inet6_bind,
- .udp6_lib_lookup = __udp6_lib_lookup,
- .ipv6_setsockopt = do_ipv6_setsockopt,
- .ipv6_getsockopt = do_ipv6_getsockopt,
- .ipv6_dev_get_saddr = ipv6_dev_get_saddr,
-};
-
static int __init inet6_init(void)
{
struct list_head *r;
@@ -1199,7 +1191,6 @@ static int __init inet6_init(void)
/* ensure that ipv6 stubs are visible only after ipv6 is ready */
wmb();
ipv6_stub = &ipv6_stub_impl;
- ipv6_bpf_stub = &ipv6_bpf_stub_impl;
out:
return err;
--
2.53.0