[PATCH 5/6] virtio/vsock: add support for dgram

Bobby Eshleman
2022-08-15T17:56:54Z

This patch supports dgram in virtio and on the vhost side.

Signed-off-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
drivers/vhost/vsock.c | 2 +-
include/net/af_vsock.h | 2 +
include/uapi/linux/virtio_vsock.h | 1 +
net/vmw_vsock/af_vsock.c | 26 +++-
net/vmw_vsock/virtio_transport.c | 2 +-
net/vmw_vsock/virtio_transport_common.c | 173 ++++++++++++++++++++++--
6 files changed, 186 insertions(+), 20 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index a5d1bdb786fe..3dc72a5647ca 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -925,7 +925,7 @@ static int __init vhost_vsock_init(void)
int ret;

ret = vsock_core_register(&vhost_transport.transport,
- VSOCK_TRANSPORT_F_H2G);
+ VSOCK_TRANSPORT_F_H2G | VSOCK_TRANSPORT_F_DGRAM);
if (ret < 0)
return ret;

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 1c53c4c4d88f..37e55c81e4df 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -78,6 +78,8 @@ struct vsock_sock {
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);
+int vsock_bind_stream(struct vsock_sock *vsk,
+ struct sockaddr_vm *addr);

/**** TRANSPORT ****/

diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
index 857df3a3a70d..0975b9c88292 100644
--- a/include/uapi/linux/virtio_vsock.h
+++ b/include/uapi/linux/virtio_vsock.h
@@ -70,6 +70,7 @@ struct virtio_vsock_hdr {
enum virtio_vsock_type {
VIRTIO_VSOCK_TYPE_STREAM = 1,
VIRTIO_VSOCK_TYPE_SEQPACKET = 2,
+ VIRTIO_VSOCK_TYPE_DGRAM = 3,
};

enum virtio_vsock_op {
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 1893f8aafa48..87e4ae1866d3 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -675,6 +675,19 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
return 0;
}

+int vsock_bind_stream(struct vsock_sock *vsk,
+ struct sockaddr_vm *addr)
+{
+ int retval;
+
+ spin_lock_bh(&vsock_table_lock);
+ retval = __vsock_bind_connectible(vsk, addr);
+ spin_unlock_bh(&vsock_table_lock);
+
+ return retval;
+}
+EXPORT_SYMBOL(vsock_bind_stream);
+
static int __vsock_bind_dgram(struct vsock_sock *vsk,
struct sockaddr_vm *addr)
{
@@ -2363,11 +2376,16 @@ int vsock_core_register(const struct vsock_transport *t, int features)
}

if (features & VSOCK_TRANSPORT_F_DGRAM) {
- if (t_dgram) {
- err = -EBUSY;
- goto err_busy;
+ /* TODO: always chose the G2H variant over others, support nesting later */
+ if (features & VSOCK_TRANSPORT_F_G2H) {
+ if (t_dgram)
+ pr_warn("virtio_vsock: t_dgram already set\n");
+ t_dgram = t;
+ }
+
+ if (!t_dgram) {
+ t_dgram = t;
}
- t_dgram = t;
}

if (features & VSOCK_TRANSPORT_F_LOCAL) {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 073314312683..d4526ca462d2 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -850,7 +850,7 @@ static int __init virtio_vsock_init(void)
return -ENOMEM;

ret = vsock_core_register(&virtio_transport.transport,
- VSOCK_TRANSPORT_F_G2H);
+ VSOCK_TRANSPORT_F_G2H | VSOCK_TRANSPORT_F_DGRAM);
if (ret)
goto out_wq;

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index bdf16fff054f..aedb48728677 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -229,7 +229,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);

static u16 virtio_transport_get_type(struct sock *sk)
{
- if (sk->sk_type == SOCK_STREAM)
+ if (sk->sk_type == SOCK_DGRAM)
+ return VIRTIO_VSOCK_TYPE_DGRAM;
+ else if (sk->sk_type == SOCK_STREAM)
return VIRTIO_VSOCK_TYPE_STREAM;
else
return VIRTIO_VSOCK_TYPE_SEQPACKET;
@@ -287,22 +289,29 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
vvs = vsk->trans;

/* we can send less than pkt_len bytes */
- if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
- pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
+ if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
+ if (info->type != VIRTIO_VSOCK_TYPE_DGRAM)
+ pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
+ else
+ return 0;
+ }

- /* virtio_transport_get_credit might return less than pkt_len credit */
- pkt_len = virtio_transport_get_credit(vvs, pkt_len);
+ if (info->type != VIRTIO_VSOCK_TYPE_DGRAM) {
+ /* virtio_transport_get_credit might return less than pkt_len credit */
+ pkt_len = virtio_transport_get_credit(vvs, pkt_len);

- /* Do not send zero length OP_RW pkt */
- if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
- return pkt_len;
+ /* Do not send zero length OP_RW pkt */
+ if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
+ return pkt_len;
+ }

skb = virtio_transport_alloc_skb(info, pkt_len,
src_cid, src_port,
dst_cid, dst_port,
&err);
if (!skb) {
- virtio_transport_put_credit(vvs, pkt_len);
+ if (info->type != VIRTIO_VSOCK_TYPE_DGRAM)
+ virtio_transport_put_credit(vvs, pkt_len);
return err;
}

@@ -586,6 +595,61 @@ virtio_transport_seqpacket_dequeue(struct vsock_sock *vsk,
}
EXPORT_SYMBOL_GPL(virtio_transport_seqpacket_dequeue);

+static ssize_t
+virtio_transport_dgram_do_dequeue(struct vsock_sock *vsk,
+ struct msghdr *msg, size_t len)
+{
+ struct virtio_vsock_sock *vvs = vsk->trans;
+ struct sk_buff *skb;
+ size_t total = 0;
+ u32 free_space;
+ int err = -EFAULT;
+
+ spin_lock_bh(&vvs->rx_lock);
+ if (total < len && !skb_queue_empty_lockless(&vvs->rx_queue)) {
+ skb = __skb_dequeue(&vvs->rx_queue);
+
+ total = len;
+ if (total > skb->len - vsock_metadata(skb)->off)
+ total = skb->len - vsock_metadata(skb)->off;
+ else if (total < skb->len - vsock_metadata(skb)->off)
+ msg->msg_flags |= MSG_TRUNC;
+
+ /* sk_lock is held by caller so no one else can dequeue.
+ * Unlock rx_lock since memcpy_to_msg() may sleep.
+ */
+ spin_unlock_bh(&vvs->rx_lock);
+
+ err = memcpy_to_msg(msg, skb->data + vsock_metadata(skb)->off, total);
+ if (err)
+ return err;
+
+ spin_lock_bh(&vvs->rx_lock);
+
+ virtio_transport_dec_rx_pkt(vvs, skb);
+ consume_skb(skb);
+ }
+
+ free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt);
+
+ spin_unlock_bh(&vvs->rx_lock);
+
+ if (total > 0 && msg->msg_name) {
+ /* Provide the address of the sender. */
+ DECLARE_SOCKADDR(struct sockaddr_vm *, vm_addr, msg->msg_name);
+
+ vsock_addr_init(vm_addr, le64_to_cpu(vsock_hdr(skb)->src_cid),
+ le32_to_cpu(vsock_hdr(skb)->src_port));
+ msg->msg_namelen = sizeof(*vm_addr);
+ }
+ return total;
+}
+
+static s64 virtio_transport_dgram_has_data(struct vsock_sock *vsk)
+{
+ return virtio_transport_stream_has_data(vsk);
+}
+
int
virtio_transport_seqpacket_enqueue(struct vsock_sock *vsk,
struct msghdr *msg,
@@ -611,7 +675,66 @@ virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t len, int flags)
{
- return -EOPNOTSUPP;
+ struct sock *sk;
+ size_t err = 0;
+ long timeout;
+
+ DEFINE_WAIT(wait);
+
+ sk = &vsk->sk;
+ err = 0;
+
+ if (flags & MSG_OOB || flags & MSG_ERRQUEUE || flags & MSG_PEEK)
+ return -EOPNOTSUPP;
+
+ lock_sock(sk);
+
+ if (!len)
+ goto out;
+
+ timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+ while (1) {
+ s64 ready;
+
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ ready = virtio_transport_dgram_has_data(vsk);
+
+ if (ready == 0) {
+ if (timeout == 0) {
+ err = -EAGAIN;
+ finish_wait(sk_sleep(sk), &wait);
+ break;
+ }
+
+ release_sock(sk);
+ timeout = schedule_timeout(timeout);
+ lock_sock(sk);
+
+ if (signal_pending(current)) {
+ err = sock_intr_errno(timeout);
+ finish_wait(sk_sleep(sk), &wait);
+ break;
+ } else if (timeout == 0) {
+ err = -EAGAIN;
+ finish_wait(sk_sleep(sk), &wait);
+ break;
+ }
+ } else {
+ finish_wait(sk_sleep(sk), &wait);
+
+ if (ready < 0) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = virtio_transport_dgram_do_dequeue(vsk, msg, len);
+ break;
+ }
+ }
+out:
+ release_sock(sk);
+ return err;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);

@@ -819,13 +942,13 @@ EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
int virtio_transport_dgram_bind(struct vsock_sock *vsk,
struct sockaddr_vm *addr)
{
- return -EOPNOTSUPP;
+ return vsock_bind_stream(vsk, addr);
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);

bool virtio_transport_dgram_allow(u32 cid, u32 port)
{
- return false;
+ return true;
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);

@@ -861,7 +984,16 @@ virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
struct msghdr *msg,
size_t dgram_len)
{
- return -EOPNOTSUPP;
+ struct virtio_vsock_pkt_info info = {
+ .op = VIRTIO_VSOCK_OP_RW,
+ .msg = msg,
+ .pkt_len = dgram_len,
+ .vsk = vsk,
+ .remote_cid = remote_addr->svm_cid,
+ .remote_port = remote_addr->svm_port,
+ };
+
+ return virtio_transport_send_pkt_info(vsk, &info);
}
EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);

@@ -1165,6 +1297,12 @@ virtio_transport_recv_connected(struct sock *sk,
struct virtio_vsock_hdr *hdr = vsock_hdr(skb);
int err = 0;

+ if (le16_to_cpu(vsock_hdr(skb)->type) == VIRTIO_VSOCK_TYPE_DGRAM) {
+ virtio_transport_recv_enqueue(vsk, skb);
+ sk->sk_data_ready(sk);
+ return err;
+ }
+
switch (le16_to_cpu(hdr->op)) {
case VIRTIO_VSOCK_OP_RW:
virtio_transport_recv_enqueue(vsk, skb);
@@ -1320,7 +1458,8 @@ virtio_transport_recv_listen(struct sock *sk, struct sk_buff *skb,
static bool virtio_transport_valid_type(u16 type)
{
return (type == VIRTIO_VSOCK_TYPE_STREAM) ||
- (type == VIRTIO_VSOCK_TYPE_SEQPACKET);
+ (type == VIRTIO_VSOCK_TYPE_SEQPACKET) ||
+ (type == VIRTIO_VSOCK_TYPE_DGRAM);
}

/* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
@@ -1384,6 +1523,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
goto free_pkt;
}

+ if (sk->sk_type == SOCK_DGRAM) {
+ virtio_transport_recv_connected(sk, skb);
+ goto out;
+ }
+
space_available = virtio_transport_space_update(sk, skb);

/* Update CID in case it has changed after a transport reset event */
@@ -1415,6 +1559,7 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
break;
}

+out:
release_sock(sk);

/* Release refcnt obtained when we fetched this socket out of the
--
2.35.1