1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */
4 #include <linux/skmsg.h>
7 #include <net/inet_common.h>
11 static struct proto *udpv6_prot_saved __read_mostly;
13 static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
14 int flags, int *addr_len)
16 #if IS_ENABLED(CONFIG_IPV6)
17 if (sk->sk_family == AF_INET6)
18 return udpv6_prot_saved->recvmsg(sk, msg, len, flags, addr_len);
20 return udp_prot.recvmsg(sk, msg, len, flags, addr_len);
23 static bool udp_sk_has_data(struct sock *sk)
25 return !skb_queue_empty(&udp_sk(sk)->reader_queue) ||
26 !skb_queue_empty(&sk->sk_receive_queue);
29 static bool psock_has_data(struct sk_psock *psock)
31 return !skb_queue_empty(&psock->ingress_skb) ||
32 !sk_psock_queue_empty(psock);
35 #define udp_msg_has_data(__sk, __psock) \
36 ({ udp_sk_has_data(__sk) || psock_has_data(__psock); })
38 static int udp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
41 DEFINE_WAIT_FUNC(wait, woken_wake_function);
44 if (sk->sk_shutdown & RCV_SHUTDOWN)
50 add_wait_queue(sk_sleep(sk), &wait);
51 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
52 ret = udp_msg_has_data(sk, psock);
54 wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
55 ret = udp_msg_has_data(sk, psock);
57 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
58 remove_wait_queue(sk_sleep(sk), &wait);
62 static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
63 int flags, int *addr_len)
65 struct sk_psock *psock;
68 if (unlikely(flags & MSG_ERRQUEUE))
69 return inet_recv_error(sk, msg, len, addr_len);
71 psock = sk_psock_get(sk);
73 return sk_udp_recvmsg(sk, msg, len, flags, addr_len);
75 if (!psock_has_data(psock)) {
76 ret = sk_udp_recvmsg(sk, msg, len, flags, addr_len);
81 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
86 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
87 data = udp_msg_wait_data(sk, psock, timeo);
89 if (psock_has_data(psock))
91 ret = sk_udp_recvmsg(sk, msg, len, flags, addr_len);
98 sk_psock_put(sk, psock);
108 static DEFINE_SPINLOCK(udpv6_prot_lock);
109 static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
111 static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
114 prot->close = sock_map_close;
115 prot->recvmsg = udp_bpf_recvmsg;
116 prot->sock_is_readable = sk_msg_is_readable;
119 static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
121 if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
122 spin_lock_bh(&udpv6_prot_lock);
123 if (likely(ops != udpv6_prot_saved)) {
124 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
125 smp_store_release(&udpv6_prot_saved, ops);
127 spin_unlock_bh(&udpv6_prot_lock);
131 static int __init udp_bpf_v4_build_proto(void)
133 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
136 late_initcall(udp_bpf_v4_build_proto);
138 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
140 int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
143 sk->sk_write_space = psock->saved_write_space;
144 WRITE_ONCE(sk->sk_prot, psock->sk_proto);
148 if (sk->sk_family == AF_INET6)
149 udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
151 WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
154 EXPORT_SYMBOL_GPL(udp_bpf_update_proto);