1
2
3
4#include <linux/skmsg.h>
5#include <net/sock.h>
6#include <net/udp.h>
7#include <net/inet_common.h>
8
9#include "udp_impl.h"
10
11static struct proto *udpv6_prot_saved __read_mostly;
12
13static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
14 int noblock, int flags, int *addr_len)
15{
16#if IS_ENABLED(CONFIG_IPV6)
17 if (sk->sk_family == AF_INET6)
18 return udpv6_prot_saved->recvmsg(sk, msg, len, noblock, flags,
19 addr_len);
20#endif
21 return udp_prot.recvmsg(sk, msg, len, noblock, flags, addr_len);
22}
23
24static bool udp_sk_has_data(struct sock *sk)
25{
26 return !skb_queue_empty(&udp_sk(sk)->reader_queue) ||
27 !skb_queue_empty(&sk->sk_receive_queue);
28}
29
30static bool psock_has_data(struct sk_psock *psock)
31{
32 return !skb_queue_empty(&psock->ingress_skb) ||
33 !sk_psock_queue_empty(psock);
34}
35
36#define udp_msg_has_data(__sk, __psock) \
37 ({ udp_sk_has_data(__sk) || psock_has_data(__psock); })
38
39static int udp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
40 long timeo)
41{
42 DEFINE_WAIT_FUNC(wait, woken_wake_function);
43 int ret = 0;
44
45 if (sk->sk_shutdown & RCV_SHUTDOWN)
46 return 1;
47
48 if (!timeo)
49 return ret;
50
51 add_wait_queue(sk_sleep(sk), &wait);
52 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
53 ret = udp_msg_has_data(sk, psock);
54 if (!ret) {
55 wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
56 ret = udp_msg_has_data(sk, psock);
57 }
58 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
59 remove_wait_queue(sk_sleep(sk), &wait);
60 return ret;
61}
62
63static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
64 int nonblock, int flags, int *addr_len)
65{
66 struct sk_psock *psock;
67 int copied, ret;
68
69 if (unlikely(flags & MSG_ERRQUEUE))
70 return inet_recv_error(sk, msg, len, addr_len);
71
72 psock = sk_psock_get(sk);
73 if (unlikely(!psock))
74 return sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
75
76 if (!psock_has_data(psock)) {
77 ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
78 goto out;
79 }
80
81msg_bytes_ready:
82 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
83 if (!copied) {
84 long timeo;
85 int data;
86
87 timeo = sock_rcvtimeo(sk, nonblock);
88 data = udp_msg_wait_data(sk, psock, timeo);
89 if (data) {
90 if (psock_has_data(psock))
91 goto msg_bytes_ready;
92 ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
93 goto out;
94 }
95 copied = -EAGAIN;
96 }
97 ret = copied;
98out:
99 sk_psock_put(sk, psock);
100 return ret;
101}
102
103enum {
104 UDP_BPF_IPV4,
105 UDP_BPF_IPV6,
106 UDP_BPF_NUM_PROTS,
107};
108
109static DEFINE_SPINLOCK(udpv6_prot_lock);
110static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
111
112static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
113{
114 *prot = *base;
115 prot->close = sock_map_close;
116 prot->recvmsg = udp_bpf_recvmsg;
117 prot->sock_is_readable = sk_msg_is_readable;
118}
119
120static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
121{
122 if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
123 spin_lock_bh(&udpv6_prot_lock);
124 if (likely(ops != udpv6_prot_saved)) {
125 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
126 smp_store_release(&udpv6_prot_saved, ops);
127 }
128 spin_unlock_bh(&udpv6_prot_lock);
129 }
130}
131
132static int __init udp_bpf_v4_build_proto(void)
133{
134 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
135 return 0;
136}
137late_initcall(udp_bpf_v4_build_proto);
138
139int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
140{
141 int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
142
143 if (restore) {
144 sk->sk_write_space = psock->saved_write_space;
145 WRITE_ONCE(sk->sk_prot, psock->sk_proto);
146 return 0;
147 }
148
149 if (sk->sk_family == AF_INET6)
150 udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
151
152 WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
153 return 0;
154}
155EXPORT_SYMBOL_GPL(udp_bpf_update_proto);
156
