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 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 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 core_initcall(udp_bpf_v4_build_proto); 43 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