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
udp_bpf_rebuild_protos(struct proto * prot,const struct proto * base)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
udp_bpf_check_v6_needs_rebuild(struct proto * ops)25 static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
26 {
27 if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
28 spin_lock_bh(&udpv6_prot_lock);
29 if (likely(ops != udpv6_prot_saved)) {
30 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
31 smp_store_release(&udpv6_prot_saved, ops);
32 }
33 spin_unlock_bh(&udpv6_prot_lock);
34 }
35 }
36
udp_bpf_v4_build_proto(void)37 static int __init udp_bpf_v4_build_proto(void)
38 {
39 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
40 return 0;
41 }
42 late_initcall(udp_bpf_v4_build_proto);
43
udp_bpf_get_proto(struct sock * sk,struct sk_psock * psock)44 struct proto *udp_bpf_get_proto(struct sock *sk, struct sk_psock *psock)
45 {
46 int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
47
48 if (sk->sk_family == AF_INET6)
49 udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
50
51 return &udp_bpf_prots[family];
52 }
53