--- /dev/null
+/*
+ * common code for virtio vsock
+ *
+ * Copyright (C) 2013-2015 Red Hat, Inc.
+ * Author: Asias He <asias@redhat.com>
+ *         Stefan Hajnoczi <stefanha@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ */
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_vsock.h>
+
+#include <net/sock.h>
+#include <net/af_vsock.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/vsock_virtio_transport_common.h>
+
+/* How long to wait for graceful shutdown of a connection */
+#define VSOCK_CLOSE_TIMEOUT (8 * HZ)
+
+static const struct virtio_transport *virtio_transport_get_ops(void)
+{
+       const struct vsock_transport *t = vsock_core_get_transport();
+
+       return container_of(t, struct virtio_transport, transport);
+}
+
+struct virtio_vsock_pkt *
+virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
+                          size_t len,
+                          u32 src_cid,
+                          u32 src_port,
+                          u32 dst_cid,
+                          u32 dst_port)
+{
+       struct virtio_vsock_pkt *pkt;
+       int err;
+
+       pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+       if (!pkt)
+               return NULL;
+
+       pkt->hdr.type           = cpu_to_le16(info->type);
+       pkt->hdr.op             = cpu_to_le16(info->op);
+       pkt->hdr.src_cid        = cpu_to_le64(src_cid);
+       pkt->hdr.dst_cid        = cpu_to_le64(dst_cid);
+       pkt->hdr.src_port       = cpu_to_le32(src_port);
+       pkt->hdr.dst_port       = cpu_to_le32(dst_port);
+       pkt->hdr.flags          = cpu_to_le32(info->flags);
+       pkt->len                = len;
+       pkt->hdr.len            = cpu_to_le32(len);
+       pkt->reply              = info->reply;
+
+       if (info->msg && len > 0) {
+               pkt->buf = kmalloc(len, GFP_KERNEL);
+               if (!pkt->buf)
+                       goto out_pkt;
+               err = memcpy_from_msg(pkt->buf, info->msg, len);
+               if (err)
+                       goto out;
+       }
+
+       trace_virtio_transport_alloc_pkt(src_cid, src_port,
+                                        dst_cid, dst_port,
+                                        len,
+                                        info->type,
+                                        info->op,
+                                        info->flags);
+
+       return pkt;
+
+out:
+       kfree(pkt->buf);
+out_pkt:
+       kfree(pkt);
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_alloc_pkt);
+
+static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
+                                         struct virtio_vsock_pkt_info *info)
+{
+       u32 src_cid, src_port, dst_cid, dst_port;
+       struct virtio_vsock_sock *vvs;
+       struct virtio_vsock_pkt *pkt;
+       u32 pkt_len = info->pkt_len;
+
+       src_cid = vm_sockets_get_local_cid();
+       src_port = vsk->local_addr.svm_port;
+       if (!info->remote_cid) {
+               dst_cid = vsk->remote_addr.svm_cid;
+               dst_port = vsk->remote_addr.svm_port;
+       } else {
+               dst_cid = info->remote_cid;
+               dst_port = info->remote_port;
+       }
+
+       vvs = vsk->trans;
+
+       /* we can send less than pkt_len bytes */
+       if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
+               pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+
+       /* 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;
+
+       pkt = virtio_transport_alloc_pkt(info, pkt_len,
+                                        src_cid, src_port,
+                                        dst_cid, dst_port);
+       if (!pkt) {
+               virtio_transport_put_credit(vvs, pkt_len);
+               return -ENOMEM;
+       }
+
+       virtio_transport_inc_tx_pkt(vvs, pkt);
+
+       return virtio_transport_get_ops()->send_pkt(pkt);
+}
+
+static void virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
+                                       struct virtio_vsock_pkt *pkt)
+{
+       vvs->rx_bytes += pkt->len;
+}
+
+static void virtio_transport_dec_rx_pkt(struct virtio_vsock_sock *vvs,
+                                       struct virtio_vsock_pkt *pkt)
+{
+       vvs->rx_bytes -= pkt->len;
+       vvs->fwd_cnt += pkt->len;
+}
+
+void virtio_transport_inc_tx_pkt(struct virtio_vsock_sock *vvs, struct virtio_vsock_pkt *pkt)
+{
+       spin_lock_bh(&vvs->tx_lock);
+       pkt->hdr.fwd_cnt = cpu_to_le32(vvs->fwd_cnt);
+       pkt->hdr.buf_alloc = cpu_to_le32(vvs->buf_alloc);
+       spin_unlock_bh(&vvs->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_inc_tx_pkt);
+
+u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
+{
+       u32 ret;
+
+       spin_lock_bh(&vvs->tx_lock);
+       ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
+       if (ret > credit)
+               ret = credit;
+       vvs->tx_cnt += ret;
+       spin_unlock_bh(&vvs->tx_lock);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
+
+void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
+{
+       spin_lock_bh(&vvs->tx_lock);
+       vvs->tx_cnt -= credit;
+       spin_unlock_bh(&vvs->tx_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_put_credit);
+
+static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
+                                              int type,
+                                              struct virtio_vsock_hdr *hdr)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
+               .type = type,
+       };
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+
+static ssize_t
+virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
+                                  struct msghdr *msg,
+                                  size_t len)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       struct virtio_vsock_pkt *pkt;
+       size_t bytes, total = 0;
+       int err = -EFAULT;
+
+       spin_lock_bh(&vvs->rx_lock);
+       while (total < len && !list_empty(&vvs->rx_queue)) {
+               pkt = list_first_entry(&vvs->rx_queue,
+                                      struct virtio_vsock_pkt, list);
+
+               bytes = len - total;
+               if (bytes > pkt->len - pkt->off)
+                       bytes = pkt->len - pkt->off;
+
+               /* 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, pkt->buf + pkt->off, bytes);
+               if (err)
+                       goto out;
+
+               spin_lock_bh(&vvs->rx_lock);
+
+               total += bytes;
+               pkt->off += bytes;
+               if (pkt->off == pkt->len) {
+                       virtio_transport_dec_rx_pkt(vvs, pkt);
+                       list_del(&pkt->list);
+                       virtio_transport_free_pkt(pkt);
+               }
+       }
+       spin_unlock_bh(&vvs->rx_lock);
+
+       /* Send a credit pkt to peer */
+       virtio_transport_send_credit_update(vsk, VIRTIO_VSOCK_TYPE_STREAM,
+                                           NULL);
+
+       return total;
+
+out:
+       if (total)
+               err = total;
+       return err;
+}
+
+ssize_t
+virtio_transport_stream_dequeue(struct vsock_sock *vsk,
+                               struct msghdr *msg,
+                               size_t len, int flags)
+{
+       if (flags & MSG_PEEK)
+               return -EOPNOTSUPP;
+
+       return virtio_transport_stream_do_dequeue(vsk, msg, len);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
+
+int
+virtio_transport_dgram_dequeue(struct vsock_sock *vsk,
+                              struct msghdr *msg,
+                              size_t len, int flags)
+{
+       return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_dequeue);
+
+s64 virtio_transport_stream_has_data(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       s64 bytes;
+
+       spin_lock_bh(&vvs->rx_lock);
+       bytes = vvs->rx_bytes;
+       spin_unlock_bh(&vvs->rx_lock);
+
+       return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_data);
+
+static s64 virtio_transport_has_space(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       s64 bytes;
+
+       bytes = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
+       if (bytes < 0)
+               bytes = 0;
+
+       return bytes;
+}
+
+s64 virtio_transport_stream_has_space(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       s64 bytes;
+
+       spin_lock_bh(&vvs->tx_lock);
+       bytes = virtio_transport_has_space(vsk);
+       spin_unlock_bh(&vvs->tx_lock);
+
+       return bytes;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_has_space);
+
+int virtio_transport_do_socket_init(struct vsock_sock *vsk,
+                                   struct vsock_sock *psk)
+{
+       struct virtio_vsock_sock *vvs;
+
+       vvs = kzalloc(sizeof(*vvs), GFP_KERNEL);
+       if (!vvs)
+               return -ENOMEM;
+
+       vsk->trans = vvs;
+       vvs->vsk = vsk;
+       if (psk) {
+               struct virtio_vsock_sock *ptrans = psk->trans;
+
+               vvs->buf_size   = ptrans->buf_size;
+               vvs->buf_size_min = ptrans->buf_size_min;
+               vvs->buf_size_max = ptrans->buf_size_max;
+               vvs->peer_buf_alloc = ptrans->peer_buf_alloc;
+       } else {
+               vvs->buf_size = VIRTIO_VSOCK_DEFAULT_BUF_SIZE;
+               vvs->buf_size_min = VIRTIO_VSOCK_DEFAULT_MIN_BUF_SIZE;
+               vvs->buf_size_max = VIRTIO_VSOCK_DEFAULT_MAX_BUF_SIZE;
+       }
+
+       vvs->buf_alloc = vvs->buf_size;
+
+       spin_lock_init(&vvs->rx_lock);
+       spin_lock_init(&vvs->tx_lock);
+       INIT_LIST_HEAD(&vvs->rx_queue);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_do_socket_init);
+
+u64 virtio_transport_get_buffer_size(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       return vvs->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_buffer_size);
+
+u64 virtio_transport_get_min_buffer_size(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       return vvs->buf_size_min;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_min_buffer_size);
+
+u64 virtio_transport_get_max_buffer_size(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       return vvs->buf_size_max;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_get_max_buffer_size);
+
+void virtio_transport_set_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+               val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+       if (val < vvs->buf_size_min)
+               vvs->buf_size_min = val;
+       if (val > vvs->buf_size_max)
+               vvs->buf_size_max = val;
+       vvs->buf_size = val;
+       vvs->buf_alloc = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_buffer_size);
+
+void virtio_transport_set_min_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+               val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+       if (val > vvs->buf_size)
+               vvs->buf_size = val;
+       vvs->buf_size_min = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_min_buffer_size);
+
+void virtio_transport_set_max_buffer_size(struct vsock_sock *vsk, u64 val)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       if (val > VIRTIO_VSOCK_MAX_BUF_SIZE)
+               val = VIRTIO_VSOCK_MAX_BUF_SIZE;
+       if (val < vvs->buf_size)
+               vvs->buf_size = val;
+       vvs->buf_size_max = val;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_set_max_buffer_size);
+
+int
+virtio_transport_notify_poll_in(struct vsock_sock *vsk,
+                               size_t target,
+                               bool *data_ready_now)
+{
+       if (vsock_stream_has_data(vsk))
+               *data_ready_now = true;
+       else
+               *data_ready_now = false;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_in);
+
+int
+virtio_transport_notify_poll_out(struct vsock_sock *vsk,
+                                size_t target,
+                                bool *space_avail_now)
+{
+       s64 free_space;
+
+       free_space = vsock_stream_has_space(vsk);
+       if (free_space > 0)
+               *space_avail_now = true;
+       else if (free_space == 0)
+               *space_avail_now = false;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_poll_out);
+
+int virtio_transport_notify_recv_init(struct vsock_sock *vsk,
+       size_t target, struct vsock_transport_recv_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_init);
+
+int virtio_transport_notify_recv_pre_block(struct vsock_sock *vsk,
+       size_t target, struct vsock_transport_recv_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_block);
+
+int virtio_transport_notify_recv_pre_dequeue(struct vsock_sock *vsk,
+       size_t target, struct vsock_transport_recv_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_pre_dequeue);
+
+int virtio_transport_notify_recv_post_dequeue(struct vsock_sock *vsk,
+       size_t target, ssize_t copied, bool data_read,
+       struct vsock_transport_recv_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_recv_post_dequeue);
+
+int virtio_transport_notify_send_init(struct vsock_sock *vsk,
+       struct vsock_transport_send_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_init);
+
+int virtio_transport_notify_send_pre_block(struct vsock_sock *vsk,
+       struct vsock_transport_send_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_block);
+
+int virtio_transport_notify_send_pre_enqueue(struct vsock_sock *vsk,
+       struct vsock_transport_send_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_pre_enqueue);
+
+int virtio_transport_notify_send_post_enqueue(struct vsock_sock *vsk,
+       ssize_t written, struct vsock_transport_send_notify_data *data)
+{
+       return 0;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_notify_send_post_enqueue);
+
+u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       return vvs->buf_size;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_rcvhiwat);
+
+bool virtio_transport_stream_is_active(struct vsock_sock *vsk)
+{
+       return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_is_active);
+
+bool virtio_transport_stream_allow(u32 cid, u32 port)
+{
+       return true;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
+
+int virtio_transport_dgram_bind(struct vsock_sock *vsk,
+                               struct sockaddr_vm *addr)
+{
+       return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_bind);
+
+bool virtio_transport_dgram_allow(u32 cid, u32 port)
+{
+       return false;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
+
+int virtio_transport_connect(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_REQUEST,
+               .type = VIRTIO_VSOCK_TYPE_STREAM,
+       };
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_connect);
+
+int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_SHUTDOWN,
+               .type = VIRTIO_VSOCK_TYPE_STREAM,
+               .flags = (mode & RCV_SHUTDOWN ?
+                         VIRTIO_VSOCK_SHUTDOWN_RCV : 0) |
+                        (mode & SEND_SHUTDOWN ?
+                         VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
+       };
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_shutdown);
+
+int
+virtio_transport_dgram_enqueue(struct vsock_sock *vsk,
+                              struct sockaddr_vm *remote_addr,
+                              struct msghdr *msg,
+                              size_t dgram_len)
+{
+       return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL_GPL(virtio_transport_dgram_enqueue);
+
+ssize_t
+virtio_transport_stream_enqueue(struct vsock_sock *vsk,
+                               struct msghdr *msg,
+                               size_t len)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_RW,
+               .type = VIRTIO_VSOCK_TYPE_STREAM,
+               .msg = msg,
+               .pkt_len = len,
+       };
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_stream_enqueue);
+
+void virtio_transport_destruct(struct vsock_sock *vsk)
+{
+       struct virtio_vsock_sock *vvs = vsk->trans;
+
+       kfree(vvs);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_destruct);
+
+static int virtio_transport_reset(struct vsock_sock *vsk,
+                                 struct virtio_vsock_pkt *pkt)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_RST,
+               .type = VIRTIO_VSOCK_TYPE_STREAM,
+               .reply = !!pkt,
+       };
+
+       /* Send RST only if the original pkt is not a RST pkt */
+       if (pkt && le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
+               return 0;
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+
+/* Normally packets are associated with a socket.  There may be no socket if an
+ * attempt was made to connect to a socket that does not exist.
+ */
+static int virtio_transport_reset_no_sock(struct virtio_vsock_pkt *pkt)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_RST,
+               .type = le16_to_cpu(pkt->hdr.type),
+               .reply = true,
+       };
+
+       /* Send RST only if the original pkt is not a RST pkt */
+       if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
+               return 0;
+
+       pkt = virtio_transport_alloc_pkt(&info, 0,
+                                        le32_to_cpu(pkt->hdr.dst_cid),
+                                        le32_to_cpu(pkt->hdr.dst_port),
+                                        le32_to_cpu(pkt->hdr.src_cid),
+                                        le32_to_cpu(pkt->hdr.src_port));
+       if (!pkt)
+               return -ENOMEM;
+
+       return virtio_transport_get_ops()->send_pkt(pkt);
+}
+
+static void virtio_transport_wait_close(struct sock *sk, long timeout)
+{
+       if (timeout) {
+               DEFINE_WAIT(wait);
+
+               do {
+                       prepare_to_wait(sk_sleep(sk), &wait,
+                                       TASK_INTERRUPTIBLE);
+                       if (sk_wait_event(sk, &timeout,
+                                         sock_flag(sk, SOCK_DONE)))
+                               break;
+               } while (!signal_pending(current) && timeout);
+
+               finish_wait(sk_sleep(sk), &wait);
+       }
+}
+
+static void virtio_transport_do_close(struct vsock_sock *vsk,
+                                     bool cancel_timeout)
+{
+       struct sock *sk = sk_vsock(vsk);
+
+       sock_set_flag(sk, SOCK_DONE);
+       vsk->peer_shutdown = SHUTDOWN_MASK;
+       if (vsock_stream_has_data(vsk) <= 0)
+               sk->sk_state = SS_DISCONNECTING;
+       sk->sk_state_change(sk);
+
+       if (vsk->close_work_scheduled &&
+           (!cancel_timeout || cancel_delayed_work(&vsk->close_work))) {
+               vsk->close_work_scheduled = false;
+
+               vsock_remove_sock(vsk);
+
+               /* Release refcnt obtained when we scheduled the timeout */
+               sock_put(sk);
+       }
+}
+
+static void virtio_transport_close_timeout(struct work_struct *work)
+{
+       struct vsock_sock *vsk =
+               container_of(work, struct vsock_sock, close_work.work);
+       struct sock *sk = sk_vsock(vsk);
+
+       sock_hold(sk);
+       lock_sock(sk);
+
+       if (!sock_flag(sk, SOCK_DONE)) {
+               (void)virtio_transport_reset(vsk, NULL);
+
+               virtio_transport_do_close(vsk, false);
+       }
+
+       vsk->close_work_scheduled = false;
+
+       release_sock(sk);
+       sock_put(sk);
+}
+
+/* User context, vsk->sk is locked */
+static bool virtio_transport_close(struct vsock_sock *vsk)
+{
+       struct sock *sk = &vsk->sk;
+
+       if (!(sk->sk_state == SS_CONNECTED ||
+             sk->sk_state == SS_DISCONNECTING))
+               return true;
+
+       /* Already received SHUTDOWN from peer, reply with RST */
+       if ((vsk->peer_shutdown & SHUTDOWN_MASK) == SHUTDOWN_MASK) {
+               (void)virtio_transport_reset(vsk, NULL);
+               return true;
+       }
+
+       if ((sk->sk_shutdown & SHUTDOWN_MASK) != SHUTDOWN_MASK)
+               (void)virtio_transport_shutdown(vsk, SHUTDOWN_MASK);
+
+       if (sock_flag(sk, SOCK_LINGER) && !(current->flags & PF_EXITING))
+               virtio_transport_wait_close(sk, sk->sk_lingertime);
+
+       if (sock_flag(sk, SOCK_DONE)) {
+               return true;
+       }
+
+       sock_hold(sk);
+       INIT_DELAYED_WORK(&vsk->close_work,
+                         virtio_transport_close_timeout);
+       vsk->close_work_scheduled = true;
+       schedule_delayed_work(&vsk->close_work, VSOCK_CLOSE_TIMEOUT);
+       return false;
+}
+
+void virtio_transport_release(struct vsock_sock *vsk)
+{
+       struct sock *sk = &vsk->sk;
+       bool remove_sock = true;
+
+       lock_sock(sk);
+       if (sk->sk_type == SOCK_STREAM)
+               remove_sock = virtio_transport_close(vsk);
+       release_sock(sk);
+
+       if (remove_sock)
+               vsock_remove_sock(vsk);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_release);
+
+static int
+virtio_transport_recv_connecting(struct sock *sk,
+                                struct virtio_vsock_pkt *pkt)
+{
+       struct vsock_sock *vsk = vsock_sk(sk);
+       int err;
+       int skerr;
+
+       switch (le16_to_cpu(pkt->hdr.op)) {
+       case VIRTIO_VSOCK_OP_RESPONSE:
+               sk->sk_state = SS_CONNECTED;
+               sk->sk_socket->state = SS_CONNECTED;
+               vsock_insert_connected(vsk);
+               sk->sk_state_change(sk);
+               break;
+       case VIRTIO_VSOCK_OP_INVALID:
+               break;
+       case VIRTIO_VSOCK_OP_RST:
+               skerr = ECONNRESET;
+               err = 0;
+               goto destroy;
+       default:
+               skerr = EPROTO;
+               err = -EINVAL;
+               goto destroy;
+       }
+       return 0;
+
+destroy:
+       virtio_transport_reset(vsk, pkt);
+       sk->sk_state = SS_UNCONNECTED;
+       sk->sk_err = skerr;
+       sk->sk_error_report(sk);
+       return err;
+}
+
+static int
+virtio_transport_recv_connected(struct sock *sk,
+                               struct virtio_vsock_pkt *pkt)
+{
+       struct vsock_sock *vsk = vsock_sk(sk);
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       int err = 0;
+
+       switch (le16_to_cpu(pkt->hdr.op)) {
+       case VIRTIO_VSOCK_OP_RW:
+               pkt->len = le32_to_cpu(pkt->hdr.len);
+               pkt->off = 0;
+
+               spin_lock_bh(&vvs->rx_lock);
+               virtio_transport_inc_rx_pkt(vvs, pkt);
+               list_add_tail(&pkt->list, &vvs->rx_queue);
+               spin_unlock_bh(&vvs->rx_lock);
+
+               sk->sk_data_ready(sk);
+               return err;
+       case VIRTIO_VSOCK_OP_CREDIT_UPDATE:
+               sk->sk_write_space(sk);
+               break;
+       case VIRTIO_VSOCK_OP_SHUTDOWN:
+               if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_RCV)
+                       vsk->peer_shutdown |= RCV_SHUTDOWN;
+               if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SHUTDOWN_SEND)
+                       vsk->peer_shutdown |= SEND_SHUTDOWN;
+               if (vsk->peer_shutdown == SHUTDOWN_MASK &&
+                   vsock_stream_has_data(vsk) <= 0)
+                       sk->sk_state = SS_DISCONNECTING;
+               if (le32_to_cpu(pkt->hdr.flags))
+                       sk->sk_state_change(sk);
+               break;
+       case VIRTIO_VSOCK_OP_RST:
+               virtio_transport_do_close(vsk, true);
+               break;
+       default:
+               err = -EINVAL;
+               break;
+       }
+
+       virtio_transport_free_pkt(pkt);
+       return err;
+}
+
+static void
+virtio_transport_recv_disconnecting(struct sock *sk,
+                                   struct virtio_vsock_pkt *pkt)
+{
+       struct vsock_sock *vsk = vsock_sk(sk);
+
+       if (le16_to_cpu(pkt->hdr.op) == VIRTIO_VSOCK_OP_RST)
+               virtio_transport_do_close(vsk, true);
+}
+
+static int
+virtio_transport_send_response(struct vsock_sock *vsk,
+                              struct virtio_vsock_pkt *pkt)
+{
+       struct virtio_vsock_pkt_info info = {
+               .op = VIRTIO_VSOCK_OP_RESPONSE,
+               .type = VIRTIO_VSOCK_TYPE_STREAM,
+               .remote_cid = le32_to_cpu(pkt->hdr.src_cid),
+               .remote_port = le32_to_cpu(pkt->hdr.src_port),
+               .reply = true,
+       };
+
+       return virtio_transport_send_pkt_info(vsk, &info);
+}
+
+/* Handle server socket */
+static int
+virtio_transport_recv_listen(struct sock *sk, struct virtio_vsock_pkt *pkt)
+{
+       struct vsock_sock *vsk = vsock_sk(sk);
+       struct vsock_sock *vchild;
+       struct sock *child;
+
+       if (le16_to_cpu(pkt->hdr.op) != VIRTIO_VSOCK_OP_REQUEST) {
+               virtio_transport_reset(vsk, pkt);
+               return -EINVAL;
+       }
+
+       if (sk_acceptq_is_full(sk)) {
+               virtio_transport_reset(vsk, pkt);
+               return -ENOMEM;
+       }
+
+       child = __vsock_create(sock_net(sk), NULL, sk, GFP_KERNEL,
+                              sk->sk_type, 0);
+       if (!child) {
+               virtio_transport_reset(vsk, pkt);
+               return -ENOMEM;
+       }
+
+       sk->sk_ack_backlog++;
+
+       lock_sock_nested(child, SINGLE_DEPTH_NESTING);
+
+       child->sk_state = SS_CONNECTED;
+
+       vchild = vsock_sk(child);
+       vsock_addr_init(&vchild->local_addr, le32_to_cpu(pkt->hdr.dst_cid),
+                       le32_to_cpu(pkt->hdr.dst_port));
+       vsock_addr_init(&vchild->remote_addr, le32_to_cpu(pkt->hdr.src_cid),
+                       le32_to_cpu(pkt->hdr.src_port));
+
+       vsock_insert_connected(vchild);
+       vsock_enqueue_accept(sk, child);
+       virtio_transport_send_response(vchild, pkt);
+
+       release_sock(child);
+
+       sk->sk_data_ready(sk);
+       return 0;
+}
+
+static bool virtio_transport_space_update(struct sock *sk,
+                                         struct virtio_vsock_pkt *pkt)
+{
+       struct vsock_sock *vsk = vsock_sk(sk);
+       struct virtio_vsock_sock *vvs = vsk->trans;
+       bool space_available;
+
+       /* buf_alloc and fwd_cnt is always included in the hdr */
+       spin_lock_bh(&vvs->tx_lock);
+       vvs->peer_buf_alloc = le32_to_cpu(pkt->hdr.buf_alloc);
+       vvs->peer_fwd_cnt = le32_to_cpu(pkt->hdr.fwd_cnt);
+       space_available = virtio_transport_has_space(vsk);
+       spin_unlock_bh(&vvs->tx_lock);
+       return space_available;
+}
+
+/* We are under the virtio-vsock's vsock->rx_lock or vhost-vsock's vq->mutex
+ * lock.
+ */
+void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
+{
+       struct sockaddr_vm src, dst;
+       struct vsock_sock *vsk;
+       struct sock *sk;
+       bool space_available;
+
+       vsock_addr_init(&src, le32_to_cpu(pkt->hdr.src_cid),
+                       le32_to_cpu(pkt->hdr.src_port));
+       vsock_addr_init(&dst, le32_to_cpu(pkt->hdr.dst_cid),
+                       le32_to_cpu(pkt->hdr.dst_port));
+
+       trace_virtio_transport_recv_pkt(src.svm_cid, src.svm_port,
+                                       dst.svm_cid, dst.svm_port,
+                                       le32_to_cpu(pkt->hdr.len),
+                                       le16_to_cpu(pkt->hdr.type),
+                                       le16_to_cpu(pkt->hdr.op),
+                                       le32_to_cpu(pkt->hdr.flags),
+                                       le32_to_cpu(pkt->hdr.buf_alloc),
+                                       le32_to_cpu(pkt->hdr.fwd_cnt));
+
+       if (le16_to_cpu(pkt->hdr.type) != VIRTIO_VSOCK_TYPE_STREAM) {
+               (void)virtio_transport_reset_no_sock(pkt);
+               goto free_pkt;
+       }
+
+       /* The socket must be in connected or bound table
+        * otherwise send reset back
+        */
+       sk = vsock_find_connected_socket(&src, &dst);
+       if (!sk) {
+               sk = vsock_find_bound_socket(&dst);
+               if (!sk) {
+                       (void)virtio_transport_reset_no_sock(pkt);
+                       goto free_pkt;
+               }
+       }
+
+       vsk = vsock_sk(sk);
+
+       space_available = virtio_transport_space_update(sk, pkt);
+
+       lock_sock(sk);
+
+       /* Update CID in case it has changed after a transport reset event */
+       vsk->local_addr.svm_cid = dst.svm_cid;
+
+       if (space_available)
+               sk->sk_write_space(sk);
+
+       switch (sk->sk_state) {
+       case VSOCK_SS_LISTEN:
+               virtio_transport_recv_listen(sk, pkt);
+               virtio_transport_free_pkt(pkt);
+               break;
+       case SS_CONNECTING:
+               virtio_transport_recv_connecting(sk, pkt);
+               virtio_transport_free_pkt(pkt);
+               break;
+       case SS_CONNECTED:
+               virtio_transport_recv_connected(sk, pkt);
+               break;
+       case SS_DISCONNECTING:
+               virtio_transport_recv_disconnecting(sk, pkt);
+               virtio_transport_free_pkt(pkt);
+               break;
+       default:
+               virtio_transport_free_pkt(pkt);
+               break;
+       }
+       release_sock(sk);
+
+       /* Release refcnt obtained when we fetched this socket out of the
+        * bound or connected list.
+        */
+       sock_put(sk);
+       return;
+
+free_pkt:
+       virtio_transport_free_pkt(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
+
+void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
+{
+       kfree(pkt->buf);
+       kfree(pkt);
+}
+EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Asias He");
+MODULE_DESCRIPTION("common code for virtio vsock");