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

Bobby Eshleman
2025-10-23T18:28:12Z

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