diff options
Diffstat (limited to 'net/ipv4/udp_bpf.c')
| -rw-r--r-- | net/ipv4/udp_bpf.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c new file mode 100644 index 000000000..0735d820e --- /dev/null +++ b/net/ipv4/udp_bpf.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Cloudflare Ltd https://cloudflare.com */ + +#include <linux/skmsg.h> +#include <net/sock.h> +#include <net/udp.h> +#include <net/inet_common.h> + +#include "udp_impl.h" + +static struct proto *udpv6_prot_saved __read_mostly; + +static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + int flags, int *addr_len) +{ +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6) + return udpv6_prot_saved->recvmsg(sk, msg, len, flags, addr_len); +#endif + return udp_prot.recvmsg(sk, msg, len, flags, addr_len); +} + +static bool udp_sk_has_data(struct sock *sk) +{ + return !skb_queue_empty(&udp_sk(sk)->reader_queue) || + !skb_queue_empty(&sk->sk_receive_queue); +} + +static bool psock_has_data(struct sk_psock *psock) +{ + return !skb_queue_empty(&psock->ingress_skb) || + !sk_psock_queue_empty(psock); +} + +#define udp_msg_has_data(__sk, __psock) \ + ({ udp_sk_has_data(__sk) || psock_has_data(__psock); }) + +static int udp_msg_wait_data(struct sock *sk, struct sk_psock *psock, + long timeo) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + int ret = 0; + + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + + if (!timeo) + return ret; + + add_wait_queue(sk_sleep(sk), &wait); + sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); + ret = udp_msg_has_data(sk, psock); + if (!ret) { + wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); + ret = udp_msg_has_data(sk, psock); + } + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + remove_wait_queue(sk_sleep(sk), &wait); + return ret; +} + +static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + int flags, int *addr_len) +{ + struct sk_psock *psock; + int copied, ret; + + if (unlikely(flags & MSG_ERRQUEUE)) + return inet_recv_error(sk, msg, len, addr_len); + + if (!len) + return 0; + + psock = sk_psock_get(sk); + if (unlikely(!psock)) + return sk_udp_recvmsg(sk, msg, len, flags, addr_len); + + if (!psock_has_data(psock)) { + ret = sk_udp_recvmsg(sk, msg, len, flags, addr_len); + goto out; + } + +msg_bytes_ready: + copied = sk_msg_recvmsg(sk, psock, msg, len, flags); + if (!copied) { + long timeo; + int data; + + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + data = udp_msg_wait_data(sk, psock, timeo); + if (data) { + if (psock_has_data(psock)) + goto msg_bytes_ready; + ret = sk_udp_recvmsg(sk, msg, len, flags, addr_len); + goto out; + } + copied = -EAGAIN; + } + ret = copied; +out: + sk_psock_put(sk, psock); + return ret; +} + +enum { + UDP_BPF_IPV4, + UDP_BPF_IPV6, + UDP_BPF_NUM_PROTS, +}; + +static DEFINE_SPINLOCK(udpv6_prot_lock); +static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS]; + +static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base) +{ + *prot = *base; + prot->close = sock_map_close; + prot->recvmsg = udp_bpf_recvmsg; + prot->sock_is_readable = sk_msg_is_readable; +} + +static void udp_bpf_check_v6_needs_rebuild(struct proto *ops) +{ + if (unlikely(ops != smp_load_acquire(&udpv6_prot_saved))) { + spin_lock_bh(&udpv6_prot_lock); + if (likely(ops != udpv6_prot_saved)) { + udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV6], ops); + smp_store_release(&udpv6_prot_saved, ops); + } + spin_unlock_bh(&udpv6_prot_lock); + } +} + +static int __init udp_bpf_v4_build_proto(void) +{ + udp_bpf_rebuild_protos(&udp_bpf_prots[UDP_BPF_IPV4], &udp_prot); + return 0; +} +late_initcall(udp_bpf_v4_build_proto); + +int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) +{ + int family = sk->sk_family == AF_INET ? UDP_BPF_IPV4 : UDP_BPF_IPV6; + + if (restore) { + sk->sk_write_space = psock->saved_write_space; + sock_replace_proto(sk, psock->sk_proto); + return 0; + } + + if (sk->sk_family == AF_INET6) + udp_bpf_check_v6_needs_rebuild(psock->sk_proto); + + sock_replace_proto(sk, &udp_bpf_prots[family]); + return 0; +} +EXPORT_SYMBOL_GPL(udp_bpf_update_proto); |