[PATCH net-next v8 06/14] vsock/virtio: add netns to virtio transport common

[Bobby Eshleman <bobbyeshleman@gmail.com>]

From: Bobby Eshleman <bobbyeshleman@meta.com>

Enable network namespace support in the virtio-vsock common transport
layer by declaring namespace pointers in the transmit and receive
paths.

The changes include:
1. Add a 'net' field to virtio_vsock_pkt_info to carry the namespace
   pointer for outgoing packets.
2. Store the namespace and namespace mode in the skb control buffer when
   allocating packets (except for VIRTIO_VSOCK_OP_RST packets which do
   not have an associated socket).
3. Retrieve namespace information from skbs on the receive path for
   lookups using vsock_find_connected_socket_net() and
   vsock_find_bound_socket_net().

This allows users of virtio transport common code
(vhost-vsock/virtio-vsock) to later enable namespace support.

Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
---
Changes in v7:
- add comment explaining the !vsk case in virtio_transport_alloc_skb()
---
 include/linux/virtio_vsock.h            |  1 +
 net/vmw_vsock/virtio_transport_common.c | 21 +++++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 29290395054c..f90646f82993 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -217,6 +217,7 @@ 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_common.c b/net/vmw_vsock/virtio_transport_common.c
index dcc8a1d5851e..b8e52c71920a 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -316,6 +316,15 @@ static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *
 					 info->flags,
 					 zcopy);
 
+	/*
+	 * If there is no corresponding socket, then we don't have a
+	 * corresponding namespace. This only happens For VIRTIO_VSOCK_OP_RST.
+	 */
+	if (vsk) {
+		virtio_vsock_skb_set_net(skb, info->net);
+		virtio_vsock_skb_set_net_mode(skb, vsk->net_mode);
+	}
+
 	return skb;
 out:
 	kfree_skb(skb);
@@ -527,6 +536,7 @@ 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);
@@ -1067,6 +1077,7 @@ 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);
@@ -1082,6 +1093,7 @@ 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);
@@ -1108,6 +1120,7 @@ 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);
@@ -1145,6 +1158,7 @@ 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 */
@@ -1465,6 +1479,7 @@ 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);
@@ -1578,7 +1593,9 @@ static bool virtio_transport_valid_type(u16 type)
 void virtio_transport_recv_pkt(struct virtio_transport *t,
 			       struct sk_buff *skb)
 {
+	enum vsock_net_mode net_mode = virtio_vsock_skb_net_mode(skb);
 	struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
+	struct net *net = virtio_vsock_skb_net(skb);
 	struct sockaddr_vm src, dst;
 	struct vsock_sock *vsk;
 	struct sock *sk;
@@ -1606,9 +1623,9 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
 	/* The socket must be in connected or bound table
 	 * otherwise send reset back
 	 */
-	sk = vsock_find_connected_socket(&src, &dst);
+	sk = vsock_find_connected_socket_net(&src, &dst, net, net_mode);
 	if (!sk) {
-		sk = vsock_find_bound_socket(&dst);
+		sk = vsock_find_bound_socket_net(&dst, net, net_mode);
 		if (!sk) {
 			(void)virtio_transport_reset_no_sock(t, skb);
 			goto free_pkt;

-- 
2.47.3