[net-next,v3,1/3] vsock: support sockmap

  This patch adds sockmap support for vsock sockets. It is intended to be
usable by all transports, but only the virtio transport is implemented.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 drivers/vhost/vsock.c                   |   1 +
 include/linux/virtio_vsock.h            |   1 +
 include/net/af_vsock.h                  |  17 ++++
 net/vmw_vsock/Makefile                  |   1 +
 net/vmw_vsock/af_vsock.c                |  55 ++++++++--
 net/vmw_vsock/virtio_transport.c        |   2 +
 net/vmw_vsock/virtio_transport_common.c |  25 +++++
 net/vmw_vsock/vsock_bpf.c               | 174 ++++++++++++++++++++++++++++++++
 net/vmw_vsock/vsock_loopback.c          |   2 +
 9 files changed, 272 insertions(+), 6 deletions(-)
  

On Tue, Feb 28, 2023 at 04:36:22PM -0500, Michael S. Tsirkin wrote:
> On Tue, Feb 28, 2023 at 07:04:34PM +0000, Bobby Eshleman wrote:
> > @@ -1241,19 +1252,34 @@ static int vsock_dgram_connect(struct socket *sock,
> >  
> >  	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
> >  	sock->state = SS_CONNECTED;
> > +	sk->sk_state = TCP_ESTABLISHED;
> >  
> >  out:
> >  	release_sock(sk);
> >  	return err;
> >  }
> 
> 
> How is this related? Maybe add a comment to explain? Does
> TCP_ESTABLISHED make sense for all types of sockets?
> 

Hey Michael, definitely, I can leave a comment.

The real reason is due to this piece of logic in sockmap:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/core/sock_map.c?h=v6.2#n531

And because of it, you see the same thing in (for example)
unix_dgram_connect():
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/unix/af_unix.c?h=v6.2#n1394

I believe it makes sense for these other socket types.
  

On Tue, Feb 28, 2023 at 07:04:34PM +0000, Bobby Eshleman wrote:
> @@ -1241,19 +1252,34 @@ static int vsock_dgram_connect(struct socket *sock,
>  
>  	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
>  	sock->state = SS_CONNECTED;
> +	sk->sk_state = TCP_ESTABLISHED;
>  
>  out:
>  	release_sock(sk);
>  	return err;
>  }


How is this related? Maybe add a comment to explain? Does
TCP_ESTABLISHED make sense for all types of sockets?
  

On Sat, Feb 18, 2023 at 07:25:41AM +0000, Bobby Eshleman wrote:
>On Tue, Feb 28, 2023 at 04:36:22PM -0500, Michael S. Tsirkin wrote:
>> On Tue, Feb 28, 2023 at 07:04:34PM +0000, Bobby Eshleman wrote:
>> > @@ -1241,19 +1252,34 @@ static int vsock_dgram_connect(struct socket *sock,
>> >
>> >  	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
>> >  	sock->state = SS_CONNECTED;
>> > +	sk->sk_state = TCP_ESTABLISHED;
>> >
>> >  out:
>> >  	release_sock(sk);
>> >  	return err;
>> >  }
>>
>>
>> How is this related? Maybe add a comment to explain? Does
>> TCP_ESTABLISHED make sense for all types of sockets?
>>
>
>Hey Michael, definitely, I can leave a comment.

I agree, since I had the same doubt in previous versions, I think it's 
worth putting a comment in the code to explain why.

Since there may be a v4, I'll leave some small comments in a separate 
email.

Thanks,
Stefano

>
>The real reason is due to this piece of logic in sockmap:
>https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/core/sock_map.c?h=v6.2#n531
>
>And because of it, you see the same thing in (for example)
>unix_dgram_connect():
>https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/unix/af_unix.c?h=v6.2#n1394
>
>I believe it makes sense for these other socket types.
>
  

On Tue, Feb 28, 2023 at 07:04:34PM +0000, Bobby Eshleman wrote:
>This patch adds sockmap support for vsock sockets. It is intended to be
>usable by all transports, but only the virtio transport is implemented.
>
>Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
>---
> drivers/vhost/vsock.c                   |   1 +
> include/linux/virtio_vsock.h            |   1 +
> include/net/af_vsock.h                  |  17 ++++
> net/vmw_vsock/Makefile                  |   1 +
> net/vmw_vsock/af_vsock.c                |  55 ++++++++--
> net/vmw_vsock/virtio_transport.c        |   2 +
> net/vmw_vsock/virtio_transport_common.c |  25 +++++
> net/vmw_vsock/vsock_bpf.c               | 174 ++++++++++++++++++++++++++++++++
> net/vmw_vsock/vsock_loopback.c          |   2 +
> 9 files changed, 272 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>index 1f3b89c885cc..3c6dc036b904 100644
>--- a/drivers/vhost/vsock.c
>+++ b/drivers/vhost/vsock.c
>@@ -439,6 +439,7 @@ static struct virtio_transport vhost_transport = {
> 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
> 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>
>+		.read_skb = virtio_transport_read_skb,
> 	},
>
> 	.send_pkt = vhost_transport_send_pkt,
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 3f9c16611306..c58453699ee9 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -245,4 +245,5 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 wanted);
> void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit);
> void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
> int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
>+int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t read_actor);
> #endif /* _LINUX_VIRTIO_VSOCK_H */
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index 568a87c5e0d0..a73f5fbd296a 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -75,6 +75,7 @@ struct vsock_sock {
> 	void *trans;
> };
>
>+s64 vsock_connectible_has_data(struct vsock_sock *vsk);
> s64 vsock_stream_has_data(struct vsock_sock *vsk);
> s64 vsock_stream_has_space(struct vsock_sock *vsk);
> struct sock *vsock_create_connected(struct sock *parent);
>@@ -173,6 +174,9 @@ struct vsock_transport {
>
> 	/* Addressing. */
> 	u32 (*get_local_cid)(void);
>+
>+	/* Read a single skb */
>+	int (*read_skb)(struct vsock_sock *, skb_read_actor_t);
> };
>
> /**** CORE ****/
>@@ -225,5 +229,18 @@ int vsock_init_tap(void);
> int vsock_add_tap(struct vsock_tap *vt);
> int vsock_remove_tap(struct vsock_tap *vt);
> void vsock_deliver_tap(struct sk_buff *build_skb(void *opaque), void *opaque);
>+int vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
>+			      int flags);
>+int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>+			       size_t len, int flags);

Just because you have to resend a v4, here we can align as `checkpatch
--strict` suggests:

CHECK: Alignment should match open parenthesis
#63: FILE: include/net/af_vsock.h:235:
+int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
+			      size_t len, int flags);

>+
>+#ifdef CONFIG_BPF_SYSCALL
>+extern struct proto vsock_proto;
>+int vsock_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
>+void __init vsock_bpf_build_proto(void);
>+#else
>+static inline void __init vsock_bpf_build_proto(void)
>+{}
>+#endif
>
> #endif /* __AF_VSOCK_H__ */
>diff --git a/net/vmw_vsock/Makefile b/net/vmw_vsock/Makefile
>index 6a943ec95c4a..5da74c4a9f1d 100644
>--- a/net/vmw_vsock/Makefile
>+++ b/net/vmw_vsock/Makefile
>@@ -8,6 +8,7 @@ obj-$(CONFIG_HYPERV_VSOCKETS) += hv_sock.o
> obj-$(CONFIG_VSOCKETS_LOOPBACK) += vsock_loopback.o
>
> vsock-y += af_vsock.o af_vsock_tap.o vsock_addr.o
>+vsock-$(CONFIG_BPF_SYSCALL) += vsock_bpf.o
>
> vsock_diag-y += diag.o
>
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 19aea7cba26e..f2cc04fb8b13 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -116,10 +116,13 @@ static void vsock_sk_destruct(struct sock *sk);
> static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
>
> /* Protocol family. */
>-static struct proto vsock_proto = {
>+struct proto vsock_proto = {
> 	.name = "AF_VSOCK",
> 	.owner = THIS_MODULE,
> 	.obj_size = sizeof(struct vsock_sock),
>+#ifdef CONFIG_BPF_SYSCALL
>+	.psock_update_sk_prot = vsock_bpf_update_proto,
>+#endif
> };
>
> /* The default peer timeout indicates how long we will wait for a peer response
>@@ -865,7 +868,7 @@ s64 vsock_stream_has_data(struct vsock_sock *vsk)
> }
> EXPORT_SYMBOL_GPL(vsock_stream_has_data);
>
>-static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
>+s64 vsock_connectible_has_data(struct vsock_sock *vsk)
> {
> 	struct sock *sk = sk_vsock(vsk);
>
>@@ -874,6 +877,7 @@ static s64 vsock_connectible_has_data(struct vsock_sock *vsk)
> 	else
> 		return vsock_stream_has_data(vsk);
> }
>+EXPORT_SYMBOL_GPL(vsock_connectible_has_data);
>
> s64 vsock_stream_has_space(struct vsock_sock *vsk)
> {
>@@ -1131,6 +1135,13 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
> 	return mask;
> }
>
>+static int vsock_read_skb(struct sock *sk, skb_read_actor_t read_actor)
>+{
>+	struct vsock_sock *vsk = vsock_sk(sk);
>+
>+	return vsk->transport->read_skb(vsk, read_actor);
>+}
>+
> static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
> 			       size_t len)
> {
>@@ -1241,19 +1252,34 @@ static int vsock_dgram_connect(struct socket *sock,
>
> 	memcpy(&vsk->remote_addr, remote_addr, sizeof(vsk->remote_addr));
> 	sock->state = SS_CONNECTED;
>+	sk->sk_state = TCP_ESTABLISHED;
>
> out:
> 	release_sock(sk);
> 	return err;
> }
>
>-static int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>-			       size_t len, int flags)
>+int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
>+			size_t len, int flags)
> {
>-	struct vsock_sock *vsk = vsock_sk(sock->sk);
>+#ifdef CONFIG_BPF_SYSCALL
>+	const struct proto *prot;
>+#endif
>+	struct vsock_sock *vsk;
>+	struct sock *sk;
>+
>+	sk = sock->sk;
>+	vsk = vsock_sk(sk);
>+
>+#ifdef CONFIG_BPF_SYSCALL
>+	prot = READ_ONCE(sk->sk_prot);
>+	if (prot != &vsock_proto)
>+		return prot->recvmsg(sk, msg, len, flags, NULL);
>+#endif
>
> 	return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
> }
>+EXPORT_SYMBOL_GPL(vsock_dgram_recvmsg);
>
> static const struct proto_ops vsock_dgram_ops = {
> 	.family = PF_VSOCK,
>@@ -1272,6 +1298,7 @@ static const struct proto_ops vsock_dgram_ops = {
> 	.recvmsg = vsock_dgram_recvmsg,
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
>+	.read_skb = vsock_read_skb,
> };
>
> static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
>@@ -2086,13 +2113,16 @@ static int __vsock_seqpacket_recvmsg(struct sock *sk, struct msghdr *msg,
> 	return err;
> }
>
>-static int
>+int
> vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 			  int flags)
> {
> 	struct sock *sk;
> 	struct vsock_sock *vsk;
> 	const struct vsock_transport *transport;
>+#ifdef CONFIG_BPF_SYSCALL
>+	const struct proto *prot;
>+#endif
> 	int err;
>
> 	sk = sock->sk;
>@@ -2139,6 +2169,14 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 		goto out;
> 	}
>
>+#ifdef CONFIG_BPF_SYSCALL
>+	prot = READ_ONCE(sk->sk_prot);
>+	if (prot != &vsock_proto) {
>+		release_sock(sk);
>+		return prot->recvmsg(sk, msg, len, flags, NULL);
>+	}
>+#endif
>+
> 	if (sk->sk_type == SOCK_STREAM)
> 		err = __vsock_stream_recvmsg(sk, msg, len, flags);
> 	else
>@@ -2148,6 +2186,7 @@ vsock_connectible_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
> 	release_sock(sk);
> 	return err;
> }
>+EXPORT_SYMBOL_GPL(vsock_connectible_recvmsg);
>
> static int vsock_set_rcvlowat(struct sock *sk, int val)
> {
>@@ -2188,6 +2227,7 @@ static const struct proto_ops vsock_stream_ops = {
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
> 	.set_rcvlowat = vsock_set_rcvlowat,
>+	.read_skb = vsock_read_skb,
> };
>
> static const struct proto_ops vsock_seqpacket_ops = {
>@@ -2209,6 +2249,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
> 	.recvmsg = vsock_connectible_recvmsg,
> 	.mmap = sock_no_mmap,
> 	.sendpage = sock_no_sendpage,
>+	.read_skb = vsock_read_skb,
> };
>
> static int vsock_create(struct net *net, struct socket *sock,
>@@ -2348,6 +2389,8 @@ static int __init vsock_init(void)
> 		goto err_unregister_proto;
> 	}
>
>+	vsock_bpf_build_proto();
>+
> 	return 0;
>
> err_unregister_proto:
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index 28b5a8e8e094..e95df847176b 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -457,6 +457,8 @@ static struct virtio_transport virtio_transport = {
> 		.notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
> 		.notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
> 		.notify_buffer_size       = virtio_transport_notify_buffer_size,
>+
>+		.read_skb = virtio_transport_read_skb,
> 	},
>
> 	.send_pkt = virtio_transport_send_pkt,
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index a1581c77cf84..f64527f32385 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -1388,6 +1388,31 @@ int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *queue)
> }
> EXPORT_SYMBOL_GPL(virtio_transport_purge_skbs);
>
>+int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t recv_actor)
>+{
>+	struct virtio_vsock_sock *vvs = vsk->trans;
>+	struct sock *sk = sk_vsock(vsk);
>+	struct sk_buff *skb;
>+	int off = 0;
>+	int copied;
>+	int err;
>+
>+	spin_lock_bh(&vvs->rx_lock);
>+	/* Use __skb_recv_datagram() for race-free handling of the receive. It
>+	 * works for types other than dgrams.
>+	 */
>+	skb = __skb_recv_datagram(sk, &vvs->rx_queue, MSG_DONTWAIT, &off, &err);
>+	spin_unlock_bh(&vvs->rx_lock);
>+
>+	if (!skb)
>+		return err;
>+
>+	copied = recv_actor(sk, skb);
>+	kfree_skb(skb);
>+	return copied;
>+}
>+EXPORT_SYMBOL_GPL(virtio_transport_read_skb);
>+
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Asias He");
> MODULE_DESCRIPTION("common code for virtio vsock");
>diff --git a/net/vmw_vsock/vsock_bpf.c b/net/vmw_vsock/vsock_bpf.c
>new file mode 100644
>index 000000000000..9c71c163c684
>--- /dev/null
>+++ b/net/vmw_vsock/vsock_bpf.c
>@@ -0,0 +1,174 @@
>+// SPDX-License-Identifier: GPL-2.0
>+/* Copyright (c) 2022 Bobby Eshleman <bobby.eshleman@bytedance.com>
>+ *
>+ * Based off of net/unix/unix_bpf.c
>+ */
>+
>+#include <linux/bpf.h>
>+#include <linux/module.h>
>+#include <linux/skmsg.h>
>+#include <linux/socket.h>
>+#include <linux/wait.h>
>+#include <net/af_vsock.h>
>+#include <net/sock.h>
>+
>+#define vsock_sk_has_data(__sk, __psock)				\
>+		({	!skb_queue_empty(&(__sk)->sk_receive_queue) ||	\
>+			!skb_queue_empty(&(__psock)->ingress_skb) ||	\
>+			!list_empty(&(__psock)->ingress_msg);		\
>+		})
>+
>+static struct proto *vsock_prot_saved __read_mostly;
>+static DEFINE_SPINLOCK(vsock_prot_lock);
>+static struct proto vsock_bpf_prot;
>+
>+static bool vsock_has_data(struct sock *sk, struct sk_psock *psock)
>+{
>+	struct vsock_sock *vsk = vsock_sk(sk);
>+	s64 ret;
>+
>+	ret = vsock_connectible_has_data(vsk);
>+	if (ret > 0)
>+		return true;
>+
>+	return vsock_sk_has_data(sk, psock);
>+}
>+
>+static bool vsock_msg_wait_data(struct sock *sk, struct sk_psock *psock, long timeo)
>+{
>+	int ret;

`ret` can be bool now.

The rest LGTM.

Thanks,
Stefano