155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */
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#include <linux/skmsg.h>
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#include <net/sock.h>
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#include <net/udp.h>
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#include <net/inet_common.h>
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#include "udp_impl.h"
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static struct proto *udpv6_prot_saved __read_mostly;
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static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
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int noblock, int flags, int *addr_len)
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{
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#if IS_ENABLED(CONFIG_IPV6)
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if (sk->sk_family == AF_INET6)
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return udpv6_prot_saved->recvmsg(sk, msg, len, noblock, flags,
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addr_len);
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#endif
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return udp_prot.recvmsg(sk, msg, len, noblock, flags, addr_len);
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}
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static bool udp_sk_has_data(struct sock *sk)
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{
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return !skb_queue_empty(&udp_sk(sk)->reader_queue) ||
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!skb_queue_empty(&sk->sk_receive_queue);
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}
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static bool psock_has_data(struct sk_psock *psock)
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{
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return !skb_queue_empty(&psock->ingress_skb) ||
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!sk_psock_queue_empty(psock);
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}
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#define udp_msg_has_data(__sk, __psock) \
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({ udp_sk_has_data(__sk) || psock_has_data(__psock); })
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static int udp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
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long timeo)
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{
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DEFINE_WAIT_FUNC(wait, woken_wake_function);
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int ret = 0;
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if (sk->sk_shutdown & RCV_SHUTDOWN)
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return 1;
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if (!timeo)
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return ret;
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add_wait_queue(sk_sleep(sk), &wait);
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sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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ret = udp_msg_has_data(sk, psock);
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if (!ret) {
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wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
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ret = udp_msg_has_data(sk, psock);
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}
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sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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remove_wait_queue(sk_sleep(sk), &wait);
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return ret;
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}
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static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
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int nonblock, int flags, int *addr_len)
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{
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struct sk_psock *psock;
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int copied, ret;
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if (unlikely(flags & MSG_ERRQUEUE))
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return inet_recv_error(sk, msg, len, addr_len);
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psock = sk_psock_get(sk);
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if (unlikely(!psock))
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return sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
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if (!psock_has_data(psock)) {
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ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
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goto out;
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}
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msg_bytes_ready:
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copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
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if (!copied) {
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long timeo;
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int data;
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timeo = sock_rcvtimeo(sk, nonblock);
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data = udp_msg_wait_data(sk, psock, timeo);
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if (data) {
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if (psock_has_data(psock))
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goto msg_bytes_ready;
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ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
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goto out;
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}
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copied = -EAGAIN;
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}
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ret = copied;
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out:
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sk_psock_put(sk, psock);
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return ret;
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}
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enum {
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UDP_BPF_IPV4,
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UDP_BPF_IPV6,
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UDP_BPF_NUM_PROTS,
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};
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static DEFINE_SPINLOCK(udpv6_prot_lock);
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static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
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static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
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{
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*prot = *base;
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prot->close = sock_map_close;
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prot->recvmsg = udp_bpf_recvmsg;
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}
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static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)
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{
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if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) {
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spin_lock_bh(&udpv6_prot_lock);
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if (likely(ops != udpv6_prot_saved)) {
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udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops);
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smp_store_release(&udpv6_prot_saved, ops);
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}
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spin_unlock_bh(&udpv6_prot_lock);
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}
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}
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static int __init udp_bpf_v4_build_proto(void)
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{
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udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot);
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return 0;
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}
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late_initcall(udp_bpf_v4_build_proto);
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int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
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{
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int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6;
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if (restore) {
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sk->sk_write_space = psock->saved_write_space;
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WRITE_ONCE(sk->sk_prot, psock->sk_proto);
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return 0;
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}
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if (sk->sk_family == AF_INET6)
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udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
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WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
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return 0;
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}
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EXPORT_SYMBOL_GPL(udp_bpf_update_proto);
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