2021-07-27 00:14:52

by Jiang Wang .

Subject: [PATCH bpf-next v1 1/5] af_unix: add read_sock for stream socket types

To support sockmap for af_unix stream type, implement
read_sock, which is similar to the read_sock for unix
dgram sockets.

Signed-off-by: Jiang Wang <[email protected]>
Reviewed-by: Cong Wang <[email protected]>.
---
net/unix/af_unix.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 89927678c..32eeb4a6a 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -672,6 +672,8 @@ static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
static int unix_read_sock(struct sock *sk, read_descriptor_t *desc,
sk_read_actor_t recv_actor);
+static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
+ sk_read_actor_t recv_actor);
static int unix_dgram_connect(struct socket *, struct sockaddr *,
int, int);
static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
@@ -725,6 +727,7 @@ static const struct proto_ops unix_stream_ops = {
.shutdown = unix_shutdown,
.sendmsg = unix_stream_sendmsg,
.recvmsg = unix_stream_recvmsg,
+ .read_sock = unix_stream_read_sock,
.mmap = sock_no_mmap,
.sendpage = unix_stream_sendpage,
.splice_read = unix_stream_splice_read,
@@ -2311,6 +2314,15 @@ struct unix_stream_read_state {
unsigned int splice_flags;
};

+static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
+ sk_read_actor_t recv_actor)
+{
+ if (unlikely(sk->sk_state != TCP_ESTABLISHED))
+ return -EINVAL;
+
+ return unix_read_sock(sk, desc, recv_actor);
+}
+
static int unix_stream_read_generic(struct unix_stream_read_state *state,
bool freezable)
{
--
2.20.1

2021-07-29 08:39:34

by Jakub Sitnicki

Subject: Re: [PATCH bpf-next v1 1/5] af_unix: add read_sock for stream socket types

On Tue, Jul 27, 2021 at 02:12 AM CEST, Jiang Wang wrote:
> To support sockmap for af_unix stream type, implement
> read_sock, which is similar to the read_sock for unix
> dgram sockets.
>
> Signed-off-by: Jiang Wang <[email protected]>
> Reviewed-by: Cong Wang <[email protected]>.
> ---
> net/unix/af_unix.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index 89927678c..32eeb4a6a 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -672,6 +672,8 @@ static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
> static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
> static int unix_read_sock(struct sock *sk, read_descriptor_t *desc,
> sk_read_actor_t recv_actor);
> +static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
> + sk_read_actor_t recv_actor);
> static int unix_dgram_connect(struct socket *, struct sockaddr *,
> int, int);
> static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
> @@ -725,6 +727,7 @@ static const struct proto_ops unix_stream_ops = {
> .shutdown = unix_shutdown,
> .sendmsg = unix_stream_sendmsg,
> .recvmsg = unix_stream_recvmsg,
> + .read_sock = unix_stream_read_sock,
> .mmap = sock_no_mmap,
> .sendpage = unix_stream_sendpage,
> .splice_read = unix_stream_splice_read,
> @@ -2311,6 +2314,15 @@ struct unix_stream_read_state {
> unsigned int splice_flags;
> };
>
> +static int unix_stream_read_sock(struct sock *sk, read_descriptor_t *desc,
> + sk_read_actor_t recv_actor)
> +{
> + if (unlikely(sk->sk_state != TCP_ESTABLISHED))
> + return -EINVAL;

tcp_read_sock returns -ENOTCONN if socket is not connected.

For the sake of being consistent, and in case we start propagating the
error up the call chain, I'd use the same error code.

> +
> + return unix_read_sock(sk, desc, recv_actor);
> +}
> +
> static int unix_stream_read_generic(struct unix_stream_read_state *state,
> bool freezable)
> {