Merge branch 'for-5.7' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie...
[linux-2.6-microblaze.git] / net / ipv4 / udp_bpf.c
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */
3
4 #include <linux/skmsg.h>
5 #include <net/sock.h>
6 #include <net/udp.h>
7
8 enum {
9         UDP_BPF_IPV4,
10         UDP_BPF_IPV6,
11         UDP_BPF_NUM_PROTS,
12 };
13
14 static struct proto *udpv6_prot_saved __read_mostly;
15 static DEFINE_SPINLOCK(udpv6_prot_lock);
16 static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
17
18 static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
19 {
20         *prot        = *base;
21         prot->unhash = sock_map_unhash;
22         prot->close  = sock_map_close;
23 }
24
25 static void udp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
26 {
27         if (sk->sk_family == AF_INET6 &&
28             unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
29                 spin_lock_bh(&udpv6_prot_lock);
30                 if (likely(ops != udpv6_prot_saved)) {
31                         udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
32                         smp_store_release(&udpv6_prot_saved, ops);
33                 }
34                 spin_unlock_bh(&udpv6_prot_lock);
35         }
36 }
37
38 static int __init udp_bpf_v4_build_proto(void)
39 {
40         udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
41         return 0;
42 }
43 core_initcall(udp_bpf_v4_build_proto);
44
45 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock)
46 {
47         int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
48
49         if (!psock->sk_proto)
50                 udp_bpf_check_v6_needs_rebuild(sk, READ_ONCE(sk->sk_prot));
51
52         return &udp_bpf_prots[family];
53 }