linux/net/unix/unix_bpf.c
Oliver Hartkopp ec095263a9 net: remove noblock parameter from recvmsg() entities
The internal recvmsg() functions have two parameters 'flags' and 'noblock'
that were merged inside skb_recv_datagram(). As a follow up patch to commit
f4b41f062c ("net: remove noblock parameter from skb_recv_datagram()")
this patch removes the separate 'noblock' parameter for recvmsg().

Analogue to the referenced patch for skb_recv_datagram() the 'flags' and
'noblock' parameters are unnecessarily split up with e.g.

err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT,
                           flags & ~MSG_DONTWAIT, &addr_len);

or in

err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
                      sk, msg, size, flags & MSG_DONTWAIT,
                      flags & ~MSG_DONTWAIT, &addr_len);

instead of simply using only flags all the time and check for MSG_DONTWAIT
where needed (to preserve for the formerly separated no(n)block condition).

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-04-12 15:00:25 +02:00

176 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Cong Wang <cong.wang@bytedance.com> */
#include <linux/skmsg.h>
#include <linux/bpf.h>
#include <net/sock.h>
#include <net/af_unix.h>
#define unix_sk_has_data(__sk, __psock) \
({ !skb_queue_empty(&__sk->sk_receive_queue) || \
!skb_queue_empty(&__psock->ingress_skb) || \
!list_empty(&__psock->ingress_msg); \
})
static int unix_msg_wait_data(struct sock *sk, struct sk_psock *psock,
long timeo)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct unix_sock *u = unix_sk(sk);
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);
if (!unix_sk_has_data(sk, psock)) {
mutex_unlock(&u->iolock);
wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
mutex_lock(&u->iolock);
ret = unix_sk_has_data(sk, psock);
}
sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
remove_wait_queue(sk_sleep(sk), &wait);
return ret;
}
static int __unix_recvmsg(struct sock *sk, struct msghdr *msg,
size_t len, int flags)
{
if (sk->sk_type == SOCK_DGRAM)
return __unix_dgram_recvmsg(sk, msg, len, flags);
else
return __unix_stream_recvmsg(sk, msg, len, flags);
}
static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
size_t len, int flags, int *addr_len)
{
struct unix_sock *u = unix_sk(sk);
struct sk_psock *psock;
int copied;
psock = sk_psock_get(sk);
if (unlikely(!psock))
return __unix_recvmsg(sk, msg, len, flags);
mutex_lock(&u->iolock);
if (!skb_queue_empty(&sk->sk_receive_queue) &&
sk_psock_queue_empty(psock)) {
mutex_unlock(&u->iolock);
sk_psock_put(sk, psock);
return __unix_recvmsg(sk, msg, len, flags);
}
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 = unix_msg_wait_data(sk, psock, timeo);
if (data) {
if (!sk_psock_queue_empty(psock))
goto msg_bytes_ready;
mutex_unlock(&u->iolock);
sk_psock_put(sk, psock);
return __unix_recvmsg(sk, msg, len, flags);
}
copied = -EAGAIN;
}
mutex_unlock(&u->iolock);
sk_psock_put(sk, psock);
return copied;
}
static struct proto *unix_dgram_prot_saved __read_mostly;
static DEFINE_SPINLOCK(unix_dgram_prot_lock);
static struct proto unix_dgram_bpf_prot;
static struct proto *unix_stream_prot_saved __read_mostly;
static DEFINE_SPINLOCK(unix_stream_prot_lock);
static struct proto unix_stream_bpf_prot;
static void unix_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
{
*prot = *base;
prot->close = sock_map_close;
prot->recvmsg = unix_bpf_recvmsg;
prot->sock_is_readable = sk_msg_is_readable;
}
static void unix_stream_bpf_rebuild_protos(struct proto *prot,
const struct proto *base)
{
*prot = *base;
prot->close = sock_map_close;
prot->recvmsg = unix_bpf_recvmsg;
prot->sock_is_readable = sk_msg_is_readable;
prot->unhash = sock_map_unhash;
}
static void unix_dgram_bpf_check_needs_rebuild(struct proto *ops)
{
if (unlikely(ops != smp_load_acquire(&unix_dgram_prot_saved))) {
spin_lock_bh(&unix_dgram_prot_lock);
if (likely(ops != unix_dgram_prot_saved)) {
unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, ops);
smp_store_release(&unix_dgram_prot_saved, ops);
}
spin_unlock_bh(&unix_dgram_prot_lock);
}
}
static void unix_stream_bpf_check_needs_rebuild(struct proto *ops)
{
if (unlikely(ops != smp_load_acquire(&unix_stream_prot_saved))) {
spin_lock_bh(&unix_stream_prot_lock);
if (likely(ops != unix_stream_prot_saved)) {
unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, ops);
smp_store_release(&unix_stream_prot_saved, ops);
}
spin_unlock_bh(&unix_stream_prot_lock);
}
}
int unix_dgram_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
{
if (sk->sk_type != SOCK_DGRAM)
return -EOPNOTSUPP;
if (restore) {
sk->sk_write_space = psock->saved_write_space;
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
return 0;
}
unix_dgram_bpf_check_needs_rebuild(psock->sk_proto);
WRITE_ONCE(sk->sk_prot, &unix_dgram_bpf_prot);
return 0;
}
int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
{
if (restore) {
sk->sk_write_space = psock->saved_write_space;
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
return 0;
}
unix_stream_bpf_check_needs_rebuild(psock->sk_proto);
WRITE_ONCE(sk->sk_prot, &unix_stream_bpf_prot);
return 0;
}
void __init unix_bpf_build_proto(void)
{
unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, &unix_dgram_proto);
unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, &unix_stream_proto);
}