Re: [PATCH v2 2/3] vsock/virtio_transport_common: handle netns of received packets

[Bobby Eshleman]

On Wed, Mar 19, 2025 at 02:26:04PM +0100, Stefano Garzarella wrote:
> On Wed, Mar 12, 2025 at 01:59:36PM -0700, Bobby Eshleman wrote:
> > From: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> > 
> > This patch allows transports that use virtio_transport_common
> > to specify the network namespace where a received packet is to
> > be delivered.
> > 
> > virtio_transport and vhost_transport, for now, still do not use this
> > capability and preserve old behavior.
> 
> What about vsock_loopback?
> 

Also unaffected, I'll add that comment here too.

> > 
> > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> > Signed-off-by: Bobby Eshleman <bobbyeshleman@xxxxxxxxx>
> > ---
> > V1 -> V2
> > * use vsock_global_net()
> > * add net to skb->cb
> > * forward port for skb
> > ---
> > drivers/vhost/vsock.c                   |  1 +
> > include/linux/virtio_vsock.h            |  2 ++
> > net/vmw_vsock/virtio_transport.c        |  1 +
> > net/vmw_vsock/virtio_transport_common.c | 11 ++++++++++-
> > 4 files changed, 14 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > index 802153e230730bdbfbbb6f4ae263ae99502ef532..02e2a3551205a4398a74a167a82802d950c962f6 100644
> > --- a/drivers/vhost/vsock.c
> > +++ b/drivers/vhost/vsock.c
> > @@ -525,6 +525,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
> > 			continue;
> > 		}
> > 
> > +		VIRTIO_VSOCK_SKB_CB(skb)->net = vsock_global_net();
> 
> I'd add an helper for that.
> 
> Or, can we avoid that and pass the net parameter to
> virtio_transport_recv_pkt()?
> 

Makes sense. I like that passing it in reduces the places that cb->net is
assigned.

> > 		total_len += sizeof(*hdr) + skb->len;
> > 
> > 		/* Deliver to monitoring devices all received packets */
> > diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> > index 0387d64e2c66c69dd7ab0cad58db5cf0682ad424..e51f89559a1d92685027bf83a62c7b05dd9e566d 100644
> > --- a/include/linux/virtio_vsock.h
> > +++ b/include/linux/virtio_vsock.h
> > @@ -12,6 +12,7 @@
> > struct virtio_vsock_skb_cb {
> > 	bool reply;
> > 	bool tap_delivered;
> > +	struct net *net;
> > 	u32 offset;
> > };
> > 
> > @@ -148,6 +149,7 @@ struct virtio_vsock_pkt_info {
> > 	u32 remote_cid, remote_port;
> > 	struct vsock_sock *vsk;
> > 	struct msghdr *msg;
> > +	struct net *net;
> > 	u32 pkt_len;
> > 	u16 type;
> > 	u16 op;
> > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> > index f0e48e6911fc46cba87f7dafeb8dbc21421df254..163ddfc0808529ad6dda7992f9ec48837dd7337c 100644
> > --- a/net/vmw_vsock/virtio_transport.c
> > +++ b/net/vmw_vsock/virtio_transport.c
> > @@ -650,6 +650,7 @@ static void virtio_transport_rx_work(struct work_struct *work)
> > 
> > 			virtio_vsock_skb_rx_put(skb);
> > 			virtio_transport_deliver_tap_pkt(skb);
> > +			VIRTIO_VSOCK_SKB_CB(skb)->net = vsock_global_net();
> > 			virtio_transport_recv_pkt(&virtio_transport, skb);
> > 		}
> > 	} while (!virtqueue_enable_cb(vq));
> > diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> > index 256d2a4fe482b3cb938a681b6924be69b2065616..028591a5863b84059b8e8bbafd499cb997a0c863 100644
> > --- a/net/vmw_vsock/virtio_transport_common.c
> > +++ b/net/vmw_vsock/virtio_transport_common.c
> > @@ -314,6 +314,8 @@ static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *
> > 					 info->flags,
> > 					 zcopy);
> > 
> > +	VIRTIO_VSOCK_SKB_CB(skb)->net = info->net;
> > +
> > 	return skb;
> > out:
> > 	kfree_skb(skb);
> > @@ -523,6 +525,7 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk)
> > 	struct virtio_vsock_pkt_info info = {
> > 		.op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	return virtio_transport_send_pkt_info(vsk, &info);
> > @@ -1061,6 +1064,7 @@ int virtio_transport_connect(struct vsock_sock *vsk)
> > 	struct virtio_vsock_pkt_info info = {
> > 		.op = VIRTIO_VSOCK_OP_REQUEST,
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	return virtio_transport_send_pkt_info(vsk, &info);
> > @@ -1076,6 +1080,7 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> > 			 (mode & SEND_SHUTDOWN ?
> > 			  VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	return virtio_transport_send_pkt_info(vsk, &info);
> > @@ -1102,6 +1107,7 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> > 		.msg = msg,
> > 		.pkt_len = len,
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	return virtio_transport_send_pkt_info(vsk, &info);
> > @@ -1139,6 +1145,7 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> > 		.op = VIRTIO_VSOCK_OP_RST,
> > 		.reply = !!skb,
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	/* Send RST only if the original pkt is not a RST pkt */
> > @@ -1159,6 +1166,7 @@ static int virtio_transport_reset_no_sock(const struct virtio_transport *t,
> > 		.op = VIRTIO_VSOCK_OP_RST,
> > 		.type = le16_to_cpu(hdr->type),
> > 		.reply = true,
> > +		.net = VIRTIO_VSOCK_SKB_CB(skb)->net,
> > 	};
> > 	struct sk_buff *reply;
> > 
> > @@ -1476,6 +1484,7 @@ virtio_transport_send_response(struct vsock_sock *vsk,
> > 		.remote_port = le32_to_cpu(hdr->src_port),
> > 		.reply = true,
> > 		.vsk = vsk,
> > +		.net = sock_net(sk_vsock(vsk)),
> > 	};
> > 
> > 	return virtio_transport_send_pkt_info(vsk, &info);
> > @@ -1590,7 +1599,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> > 			       struct sk_buff *skb)
> > {
> > 	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
> > -	struct net *net = vsock_global_net();
> > +	struct net *net = VIRTIO_VSOCK_SKB_CB(skb)->net;
> > 	struct sockaddr_vm src, dst;
> > 	struct vsock_sock *vsk;
> > 	struct sock *sk;
> > 
> > -- 
> > 2.47.1
> > 
> 

Thanks!

Best,
Bobby