tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#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 int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
25 int nonblock, int flags, int *addr_len)
26{
27 struct sk_psock *psock;
28 int copied, ret;
29
30 if (unlikely(flags & MSG_ERRQUEUE))
31 return inet_recv_error(sk, msg, len, addr_len);
32
33 psock = sk_psock_get(sk);
34 if (unlikely(!psock))
35 return sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
36
37 lock_sock(sk);
38 if (sk_psock_queue_empty(psock)) {
39 ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
40 goto out;
41 }
42
43msg_bytes_ready:
44 copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
45 if (!copied) {
46 int data, err = 0;
47 long timeo;
48
49 timeo = sock_rcvtimeo(sk, nonblock);
50 data = sk_msg_wait_data(sk, psock, flags, timeo, &err);
51 if (data) {
52 if (!sk_psock_queue_empty(psock))
53 goto msg_bytes_ready;
54 ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
55 goto out;
56 }
57 if (err) {
58 ret = err;
59 goto out;
60 }
61 copied = -EAGAIN;
62 }
63 ret = copied;
64out:
65 release_sock(sk);
66 sk_psock_put(sk, psock);
67 return ret;
68}
69
70enum {
71 UDP_BPF_IPV4,
72 UDP_BPF_IPV6,
73 UDP_BPF_NUM_PROTS,
74};
75
76static DEFINE_SPINLOCK(udpv6_prot_lock);
77static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
78
79static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
80{
81 *prot = *base;
82 prot->unhash = sock_map_unhash;
83 prot->close = sock_map_close;
84 prot->recvmsg = udp_bpf_recvmsg;
85}
86
87static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
88{
89 if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
90 spin_lock_bh(&udpv6_prot_lock);
91 if (likely(ops != udpv6_prot_saved)) {
92 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
93 smp_store_release(&udpv6_prot_saved, ops);
94 }
95 spin_unlock_bh(&udpv6_prot_lock);
96 }
97}
98
99static int __init udp_bpf_v4_build_proto(void)
100{
101 udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
102 return 0;
103}
104core_initcall(udp_bpf_v4_build_proto);
105
106int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
107{
108 int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
109
110 if (restore) {
111 sk->sk_write_space = psock->saved_write_space;
112 WRITE_ONCE(sk->sk_prot, psock->sk_proto);
113 return 0;
114 }
115
116 if (sk->sk_family == AF_INET6)
117 udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
118
119 WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
120 return 0;
121}
122EXPORT_SYMBOL_GPL(udp_bpf_update_proto);