On Sun, Feb 07, 2021 at 06:15:22PM +0300, Arseny Krasnov wrote:
This adds receive loop for SEQPACKET. It looks like receive loop for
STREAM, but there is a little bit difference:
1) It doesn't call notify callbacks.
2) It doesn't care about 'SO_SNDLOWAT' and 'SO_RCVLOWAT' values, because
there is no sense for these values in SEQPACKET case.
3) It waits until whole record is received or error is found during
receiving.
4) It processes and sets 'MSG_TRUNC' flag.
So to avoid extra conditions for two types of socket inside one loop, two
independent functions were created.
Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>
---
include/net/af_vsock.h | 5 +++
net/vmw_vsock/af_vsock.c | 96 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 100 insertions(+), 1 deletion(-)
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index b1c717286993..bb6a0e52be86 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -135,6 +135,11 @@ struct vsock_transport {
bool (*stream_is_active)(struct vsock_sock *);
bool (*stream_allow)(u32 cid, u32 port);
+ /* SEQ_PACKET. */
+ size_t (*seqpacket_seq_get_len)(struct vsock_sock *);
+ int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
+ int flags, bool *msg_ready);
CHECK: Alignment should match open parenthesis
#35: FILE: include/net/af_vsock.h:141:
+ int (*seqpacket_dequeue)(struct vsock_sock *, struct msghdr *,
+ int flags, bool *msg_ready);
And to make checkpatch.pl happy please use the identifier name also for
the others parameter. I know we haven't done this before, but for new
code I think we can do it.
+
/* Notification. */
int (*notify_poll_in)(struct vsock_sock *, size_t, bool *);
int (*notify_poll_out)(struct vsock_sock *, size_t, bool *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 66c8a932f49b..3d8af987216a 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1977,6 +1977,97 @@ static int __vsock_stream_recvmsg(struct sock *sk, struct msghdr *msg,
return err;
}
+static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
+ size_t len, int flags)
+{
+ const struct vsock_transport *transport;
+ const struct iovec *orig_iov;
+ unsigned long orig_nr_segs;
+ bool msg_ready;
+ struct vsock_sock *vsk;
+ size_t record_len;
+ long timeout;
+ int err = 0;
+ DEFINE_WAIT(wait);
+
+ vsk = vsock_sk(sk);
+ transport = vsk->transport;
+
+ timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+ orig_nr_segs = msg->msg_iter.nr_segs;
+ orig_iov = msg->msg_iter.iov;
+ msg_ready = false;
+ record_len = 0;
+
+ while (1) {
+ err = vsock_wait_data(sk, &wait, timeout, NULL, 0);
+
+ if (err <= 0) {
+ /* In case of any loop break(timeout, signal
+ * interrupt or shutdown), we report user that
+ * nothing was copied.
+ */
+ err = 0;
+ break;
+ }
+
+ if (record_len == 0) {
+ record_len =
+ transport->seqpacket_seq_get_len(vsk);
+
+ if (record_len == 0)
+ continue;
+ }
+
+ err = transport->seqpacket_dequeue(vsk, msg,
+ flags, &msg_ready);
A single line here should be okay.
+ if (err < 0) {
+ if (err == -EAGAIN) {
+ iov_iter_init(&msg->msg_iter, READ,
+ orig_iov, orig_nr_segs,
+ len);
+ /* Clear 'MSG_EOR' here, because dequeue
+ * callback above set it again if it was
+ * set by sender. This 'MSG_EOR' is from
+ * dropped record.
+ */
+ msg->msg_flags &= ~MSG_EOR;
+ record_len = 0;
+ continue;
+ }
+
+ err = -ENOMEM;
+ break;
+ }
+
+ if (msg_ready)
+ break;
+ }
+
+ if (sk->sk_err)
+ err = -sk->sk_err;
+ else if (sk->sk_shutdown & RCV_SHUTDOWN)
+ err = 0;
+
+ if (msg_ready) {
+ /* User sets MSG_TRUNC, so return real length of
+ * packet.
+ */
+ if (flags & MSG_TRUNC)
+ err = record_len;
+ else
+ err = len - msg->msg_iter.count;
+
+ /* Always set MSG_TRUNC if real length of packet is
+ * bigger than user's buffer.
+ */
+ if (record_len > len)
+ msg->msg_flags |= MSG_TRUNC;
+ }
+
+ return err;
+}
+
static int
vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
int flags)
@@ -2032,7 +2123,10 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
goto out;
}
- err = __vsock_stream_recvmsg(sk, msg, len, flags);
+ if (sk->sk_type == SOCK_STREAM)
+ err = __vsock_stream_recvmsg(sk, msg, len, flags);
+ else
+ err = __vsock_seqpacket_recvmsg(sk, msg, len, flags);
out:
release_sock(sk);
The rest seems ok to me, but I need to get more familiar with SEQPACKET
before giving my R-b.
Thanks,
Stefano
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