Re: [PATCH v8 net-next 1/1] hv_sock: introduce Hyper-V Sockets

From: Cathy Avery
Date: Tue Apr 26 2016 - 12:19:22 EST

Hi,

I will be working with Dexuan to possibly port this functionality into RHEL.

Here are my initial comments. Mostly stylistic. They are prefaced by CAA.

Thanks,

Cathy Avery

On 04/07/2016 09:36 PM, Dexuan Cui wrote:
Hyper-V Sockets (hv_sock) supplies a byte-stream based communication
mechanism between the host and the guest. It's somewhat like TCP over
VMBus, but the transportation layer (VMBus) is much simpler than IP.

With Hyper-V Sockets, applications between the host and the guest can talk
to each other directly by the traditional BSD-style socket APIs.

Hyper-V Sockets is only available on new Windows hosts, like Windows Server
2016. More info is in this article "Make your own integration services":
https://msdn.microsoft.com/en-us/virtualization/hyperv_on_windows/develop/make_mgmt_service

The patch implements the necessary support in the guest side by introducing
a new socket address family AF_HYPERV.

Signed-off-by: Dexuan Cui<decui@xxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan"<kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang<haiyangz@xxxxxxxxxxxxx>
Cc: Vitaly Kuznetsov<vkuznets@xxxxxxxxxx>
---
MAINTAINERS | 2 +
include/linux/hyperv.h | 16 +
include/linux/socket.h | 5 +-
include/net/af_hvsock.h | 51 ++
include/uapi/linux/hyperv.h | 25 +
net/Kconfig | 1 +
net/Makefile | 1 +
net/hv_sock/Kconfig | 10 +
net/hv_sock/Makefile | 3 +
net/hv_sock/af_hvsock.c | 1483 +++++++++++++++++++++++++++++++++++++++++++
10 files changed, 1595 insertions(+), 2 deletions(-)
create mode 100644 include/net/af_hvsock.h
create mode 100644 net/hv_sock/Kconfig
create mode 100644 net/hv_sock/Makefile
create mode 100644 net/hv_sock/af_hvsock.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 67d99dd..7b6f203 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5267,7 +5267,9 @@ F: drivers/pci/host/pci-hyperv.c
F: drivers/net/hyperv/
F: drivers/scsi/storvsc_drv.c
F: drivers/video/fbdev/hyperv_fb.c
+F: net/hv_sock/
F: include/linux/hyperv.h
+F: include/net/af_hvsock.h
F: tools/hv/
F: Documentation/ABI/stable/sysfs-bus-vmbus
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index aa0fadc..b92439d 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1338,4 +1338,20 @@ extern __u32 vmbus_proto_version;
int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
const uuid_le *shv_host_servie_id);
+struct vmpipe_proto_header {
+ u32 pkt_type;
+ u32 data_size;
+} __packed;
+
+#define HVSOCK_HEADER_LEN (sizeof(struct vmpacket_descriptor) + \
+ sizeof(struct vmpipe_proto_header))
+
+/* See 'prev_indices' in hv_ringbuffer_read(), hv_ringbuffer_write() */
+#define PREV_INDICES_LEN (sizeof(u64))
+
+#define HVSOCK_PKT_LEN(payload_len) (HVSOCK_HEADER_LEN + \
+ ALIGN((payload_len), 8) + \
+ PREV_INDICES_LEN)
+#define HVSOCK_MIN_PKT_LEN HVSOCK_PKT_LEN(1)
+
#endif /* _HYPERV_H */
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 73bf6c6..88b1ccd 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -201,8 +201,8 @@ struct ucred {
#define AF_NFC 39 /* NFC sockets */
#define AF_VSOCK 40 /* vSockets */
#define AF_KCM 41 /* Kernel Connection Multiplexor*/
-
-#define AF_MAX 42 /* For now.. */
+#define AF_HYPERV 42 /* Hyper-V Sockets */
+#define AF_MAX 43 /* For now.. */
/* Protocol families, same as address families. */
#define PF_UNSPEC AF_UNSPEC
@@ -249,6 +249,7 @@ struct ucred {
#define PF_NFC AF_NFC
#define PF_VSOCK AF_VSOCK
#define PF_KCM AF_KCM
+#define PF_HYPERV AF_HYPERV
#define PF_MAX AF_MAX
/* Maximum queue length specifiable by listen. */
diff --git a/include/net/af_hvsock.h b/include/net/af_hvsock.h
new file mode 100644
index 0000000..a5aa28d
--- /dev/null
+++ b/include/net/af_hvsock.h
@@ -0,0 +1,51 @@
+#ifndef __AF_HVSOCK_H__
+#define __AF_HVSOCK_H__
+
+#include <linux/kernel.h>
+#include <linux/hyperv.h>
+#include <net/sock.h>
+
+#define VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV (5 * PAGE_SIZE)
+#define VMBUS_RINGBUFFER_SIZE_HVSOCK_SEND (5 * PAGE_SIZE)
+
+#define HVSOCK_RCV_BUF_SZ VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV
+#define HVSOCK_SND_BUF_SZ PAGE_SIZE
+
+#define sk_to_hvsock(__sk) ((struct hvsock_sock *)(__sk))
+#define hvsock_to_sk(__hvsk) ((struct sock *)(__hvsk))
+
+struct hvsock_sock {
+ /* sk must be the first member. */
+ struct sock sk;
+
+ struct sockaddr_hv local_addr;
+ struct sockaddr_hv remote_addr;
+
+ /* protected by the global hvsock_mutex */
+ struct list_head bound_list;
+ struct list_head connected_list;
+
+ struct list_head accept_queue;
+ /* used by enqueue and dequeue */
+ struct mutex accept_queue_mutex;
+
+ struct delayed_work dwork;
+
+ u32 peer_shutdown;
+
+ struct vmbus_channel *channel;
+
+ struct {
+ struct vmpipe_proto_header hdr;
+ char buf[HVSOCK_SND_BUF_SZ];
+ } __packed send;
+
+ struct {
+ struct vmpipe_proto_header hdr;
+ char buf[HVSOCK_RCV_BUF_SZ];
+ unsigned int data_len;
+ unsigned int data_offset;
+ } __packed recv;
+};
+
+#endif /* __AF_HVSOCK_H__ */
diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h
index e347b24..f1d0bca 100644
--- a/include/uapi/linux/hyperv.h
+++ b/include/uapi/linux/hyperv.h
@@ -26,6 +26,7 @@
#define _UAPI_HYPERV_H
#include <linux/uuid.h>
+#include <linux/socket.h>
/*
* Framework version for util services.
@@ -396,4 +397,28 @@ struct hv_kvp_ip_msg {
struct hv_kvp_ipaddr_value kvp_ip_val;
} __attribute__((packed));
+/*
+ * This is the address fromat of Hyper-V Sockets.
+ * Note: here we just borrow the kernel's built-in type uuid_le. When
+ * an application calls bind() or connect(), the 2 members of struct
+ * sockaddr_hv must be of GUID.
+ * The GUID format differs from the UUID format only in the byte order of
+ * the first 3 fields. Refer to:
+ *https://en.wikipedia.org/wiki/Globally_unique_identifier
+ */
+#define guid_t uuid_le
+struct sockaddr_hv {
+ __kernel_sa_family_t shv_family; /* Address family */
+ __le16 reserved; /* Must be Zero */
+ guid_t shv_vm_id; /* Not used. Must be Zero. */
+ guid_t shv_service_id; /* Service ID */
+};
+
+#define SHV_VMID_GUEST NULL_UUID_LE
+#define SHV_VMID_HOST NULL_UUID_LE
+
+#define SHV_SERVICE_ID_ANY NULL_UUID_LE
+
+#define SHV_PROTO_RAW 1
+
#endif /* _UAPI_HYPERV_H */
diff --git a/net/Kconfig b/net/Kconfig
index a8934d8..68d13d7 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -231,6 +231,7 @@ source "net/dns_resolver/Kconfig"
source "net/batman-adv/Kconfig"
source "net/openvswitch/Kconfig"
source "net/vmw_vsock/Kconfig"
+source "net/hv_sock/Kconfig"
source "net/netlink/Kconfig"
source "net/mpls/Kconfig"
source "net/hsr/Kconfig" diff --git a/net/Makefile b/net/Makefile index 81d1411..d115c31 100644 --- a/net/Makefile +++ b/net/Makefile @@ -70,6 +70,7 @@ obj-$(CONFIG_BATMAN_ADV) += batman-adv/ obj-$(CONFIG_NFC) += nfc/ obj-$(CONFIG_OPENVSWITCH) += openvswitch/ obj-$(CONFIG_VSOCKETS) += vmw_vsock/ +obj-$(CONFIG_HYPERV_SOCK) += hv_sock/ obj-$(CONFIG_MPLS) += mpls/ obj-$(CONFIG_HSR) += hsr/ ifneq ($(CONFIG_NET_SWITCHDEV),) diff --git a/net/hv_sock/Kconfig b/net/hv_sock/Kconfig new file mode 100644 index 0000000..1f41848 --- /dev/null +++ b/net/hv_sock/Kconfig @@ -0,0 +1,10 @@ +config HYPERV_SOCK + tristate "Hyper-V Sockets"
+ depends on HYPERV
+ default m if HYPERV
+ help
+ Hyper-V Sockets is somewhat like TCP over VMBus, allowing
+ communication between Linux guest and Hyper-V host without TCP/IP.
+
+ To compile this driver as a module, choose M here: the module
+ will be called hv_sock.
diff --git a/net/hv_sock/Makefile b/net/hv_sock/Makefile
new file mode 100644
index 0000000..716c012
--- /dev/null
+++ b/net/hv_sock/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_HYPERV_SOCK) += hv_sock.o
+
+hv_sock-y += af_hvsock.o
diff --git a/net/hv_sock/af_hvsock.c b/net/hv_sock/af_hvsock.c
new file mode 100644
index 0000000..185a382
--- /dev/null
+++ b/net/hv_sock/af_hvsock.c
@@ -0,0 +1,1483 @@
+/*
+ * Hyper-V Sockets -- a socket-based communication channel between the
+ * Hyper-V host and the virtual machines running on it.
+ *
+ * Copyright(c) 2016, Microsoft Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <net/af_hvsock.h>
+
+static struct proto hvsock_proto = {
+ .name = "HV_SOCK",
+ .owner = THIS_MODULE,
+ .obj_size = sizeof(struct hvsock_sock),
+};
+
+#define SS_LISTEN 255
+
+static LIST_HEAD(hvsock_bound_list);
+static LIST_HEAD(hvsock_connected_list);
+static DEFINE_MUTEX(hvsock_mutex);
+
+static bool uuid_equals(uuid_le u1, uuid_le u2)
+{
+ return !uuid_le_cmp(u1, u2);
+}
+
+/* NOTE: hvsock_mutex must be held when the below helper functions, whose
+ * names begin with __ hvsock, are invoked.
+ */
+static void __hvsock_insert_bound(struct list_head *list,
+ struct hvsock_sock *hvsk)
+{
+ sock_hold(&hvsk->sk);
+ list_add(&hvsk->bound_list, list);
+}
+
+static void __hvsock_insert_connected(struct list_head *list,
+ struct hvsock_sock *hvsk)
+{
+ sock_hold(&hvsk->sk);
+ list_add(&hvsk->connected_list, list);
+}
+
+static void __hvsock_remove_bound(struct hvsock_sock *hvsk)
+{
+ list_del_init(&hvsk->bound_list);
+ sock_put(&hvsk->sk);
+}
+
+static void __hvsock_remove_connected(struct hvsock_sock *hvsk)
+{
+ list_del_init(&hvsk->connected_list);
+ sock_put(&hvsk->sk);
+}
+
+static struct sock *__hvsock_find_bound_socket(const struct sockaddr_hv *addr)
+{
+ struct hvsock_sock *hvsk;
+
+ list_for_each_entry(hvsk, &hvsock_bound_list, bound_list) {
+ if (uuid_equals(addr->shv_service_id,
+ hvsk->local_addr.shv_service_id))
+ return hvsock_to_sk(hvsk);
+ }
+ return NULL;
+}
+
+static struct sock *__hvsock_find_connected_socket_by_channel(
+ const struct vmbus_channel *channel)
+{
+ struct hvsock_sock *hvsk;
+
+ list_for_each_entry(hvsk, &hvsock_connected_list, connected_list) {
+ if (hvsk->channel == channel)
+ return hvsock_to_sk(hvsk);
+ }
+ return NULL;
+}
+
+static bool __hvsock_in_bound_list(struct hvsock_sock *hvsk)
+{
+ return !list_empty(&hvsk->bound_list);
+}
+
+static bool __hvsock_in_connected_list(struct hvsock_sock *hvsk)
+{
+ return !list_empty(&hvsk->connected_list);
+}
+
+static void hvsock_insert_connected(struct hvsock_sock *hvsk)
+{
+ __hvsock_insert_connected(&hvsock_connected_list, hvsk);
+}
+
+static
+void hvsock_enqueue_accept(struct sock *listener, struct sock *connected)
+{
+ struct hvsock_sock *hvlistener;
+ struct hvsock_sock *hvconnected;
+
+ hvlistener = sk_to_hvsock(listener);
+ hvconnected = sk_to_hvsock(connected);
+
+ sock_hold(connected);
+ sock_hold(listener);
+
+ mutex_lock(&hvlistener->accept_queue_mutex);
+ list_add_tail(&hvconnected->accept_queue, &hvlistener->accept_queue);
+ listener->sk_ack_backlog++;
+ mutex_unlock(&hvlistener->accept_queue_mutex);
+}
+
+static struct sock *hvsock_dequeue_accept(struct sock *listener)
+{
+ struct hvsock_sock *hvlistener;
+ struct hvsock_sock *hvconnected;
+
+ hvlistener = sk_to_hvsock(listener);
+
+ mutex_lock(&hvlistener->accept_queue_mutex);
+
+ if (list_empty(&hvlistener->accept_queue)) {
+ mutex_unlock(&hvlistener->accept_queue_mutex);
+ return NULL;
+ }
+
+ hvconnected = list_entry(hvlistener->accept_queue.next,
+ struct hvsock_sock, accept_queue);
+
+ list_del_init(&hvconnected->accept_queue);
+ listener->sk_ack_backlog--;
+
+ mutex_unlock(&hvlistener->accept_queue_mutex);
+
+ sock_put(listener);
+ /* The caller will need a reference on the connected socket so we let
+ * it call sock_put().
+ */
+
+ return hvsock_to_sk(hvconnected);
+}
+
+static bool hvsock_is_accept_queue_empty(struct sock *sk)
+{
+ struct hvsock_sock *hvsk = sk_to_hvsock(sk);
+ int ret;
+
+ mutex_lock(&hvsk->accept_queue_mutex);
+ ret = list_empty(&hvsk->accept_queue);
+ mutex_unlock(&hvsk->accept_queue_mutex);
+
+ return ret;
+}
+
+static void hvsock_addr_init(struct sockaddr_hv *addr, uuid_le service_id)
+{
+ memset(addr, 0, sizeof(*addr));
+ addr->shv_family = AF_HYPERV;
+ addr->shv_service_id = service_id;
+}
+
+static int hvsock_addr_validate(const struct sockaddr_hv *addr)
+{
+ if (!addr)
+ return -EFAULT;
+
+ if (addr->shv_family != AF_HYPERV)
+ return -EAFNOSUPPORT;
+
+ if (addr->reserved != 0)
+ return -EINVAL;
+
+ if (!uuid_equals(addr->shv_vm_id, NULL_UUID_LE))
+ return -EINVAL;
+
+ return 0;
+}
+
+static bool hvsock_addr_bound(const struct sockaddr_hv *addr)
+{
+ return !uuid_equals(addr->shv_service_id, SHV_SERVICE_ID_ANY);
+}
+
+static int hvsock_addr_cast(const struct sockaddr *addr, size_t len,
+ struct sockaddr_hv **out_addr)
+{
+ if (len < sizeof(**out_addr))
+ return -EFAULT;
+
+ *out_addr = (struct sockaddr_hv *)addr;
+ return hvsock_addr_validate(*out_addr);
+}
+
+static int __hvsock_do_bind(struct hvsock_sock *hvsk,
+ struct sockaddr_hv *addr)
+{
+ struct sockaddr_hv hv_addr;
+ int ret = 0;
+
+ hvsock_addr_init(&hv_addr, addr->shv_service_id);
+
+ mutex_lock(&hvsock_mutex);
+
+ if (uuid_equals(addr->shv_service_id, SHV_SERVICE_ID_ANY)) {
+ do {
+ uuid_le_gen(&hv_addr.shv_service_id);
+ } while (__hvsock_find_bound_socket(&hv_addr));
+ } else {
+ if (__hvsock_find_bound_socket(&hv_addr)) {
+ ret = -EADDRINUSE;
+ goto out;
+ }
+ }
+
+ hvsock_addr_init(&hvsk->local_addr, hv_addr.shv_service_id);
+ __hvsock_insert_bound(&hvsock_bound_list, hvsk);
+
+out:
+ mutex_unlock(&hvsock_mutex);
+
+ return ret;
+}
+
+static int __hvsock_bind(struct sock *sk, struct sockaddr_hv *addr)
+{
+ struct hvsock_sock *hvsk = sk_to_hvsock(sk);
+ int ret;
+
+ if (hvsock_addr_bound(&hvsk->local_addr))
+ return -EINVAL;
+
+ switch (sk->sk_socket->type) {
+ case SOCK_STREAM:
+ ret = __hvsock_do_bind(hvsk, addr);
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+/* Autobind this socket to the local address if necessary. */
+static int hvsock_auto_bind(struct hvsock_sock *hvsk)
+{
+ struct sock *sk = hvsock_to_sk(hvsk);
+ struct sockaddr_hv local_addr;
+
+ if (hvsock_addr_bound(&hvsk->local_addr))
+ return 0;
+ hvsock_addr_init(&local_addr, SHV_SERVICE_ID_ANY);
+ return __hvsock_bind(sk, &local_addr);
+}
+
+static void hvsock_sk_destruct(struct sock *sk)
+{
+ struct hvsock_sock *hvsk = sk_to_hvsock(sk);
+ struct vmbus_channel *channel = hvsk->channel;
+
+ if (!channel)
+ return;
+
+ vmbus_hvsock_device_unregister(channel);
+}
+
+static void __hvsock_release(struct sock *sk)
+{
+ struct hvsock_sock *hvsk;
+ struct sock *pending;
+
+ hvsk = sk_to_hvsock(sk);
+
+ mutex_lock(&hvsock_mutex);
+ if (__hvsock_in_bound_list(hvsk))
+ __hvsock_remove_bound(hvsk);
+
+ if (__hvsock_in_connected_list(hvsk))
+ __hvsock_remove_connected(hvsk);
+ mutex_unlock(&hvsock_mutex);
+
+ lock_sock(sk);
+ sock_orphan(sk);
+ sk->sk_shutdown = SHUTDOWN_MASK;
+
+ /* Clean up any sockets that never were accepted. */
+ while ((pending = hvsock_dequeue_accept(sk)) != NULL) {
+ __hvsock_release(pending);
+ sock_put(pending);
+ }
+
+ release_sock(sk);
+ sock_put(sk);
+}
+
+static int hvsock_release(struct socket *sock)
+{
+ /* If accept() is interrupted by a signal, the temporary socket
+ * struct's sock->sk is NULL.
+ */
+ if (sock->sk) {
+ __hvsock_release(sock->sk);
+ sock->sk = NULL;
+ }
+
+ sock->state = SS_FREE;
+ return 0;
+}
+
+static struct sock *__hvsock_create(struct net *net, struct socket *sock,
+ gfp_t priority, unsigned short type)
+{
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ sk = sk_alloc(net, AF_HYPERV, priority, &hvsock_proto, 0);
+ if (!sk)
+ return NULL;
+
+ sock_init_data(sock, sk);
+
+ /* sk->sk_type is normally set in sock_init_data, but only if sock is
+ * non-NULL. We make sure that our sockets always have a type by
+ * setting it here if needed.
+ */
+ if (!sock)
+ sk->sk_type = type;
+
+ hvsk = sk_to_hvsock(sk);
+ hvsock_addr_init(&hvsk->local_addr, SHV_SERVICE_ID_ANY);
+ hvsock_addr_init(&hvsk->remote_addr, SHV_SERVICE_ID_ANY);
+
+ sk->sk_destruct = hvsock_sk_destruct;
+
+ /* Looks stream-based socket doesn't need this. */
+ sk->sk_backlog_rcv = NULL;
+
+ sk->sk_state = 0;
+ sock_reset_flag(sk, SOCK_DONE);
+
+ INIT_LIST_HEAD(&hvsk->bound_list);
+ INIT_LIST_HEAD(&hvsk->connected_list);
+
+ INIT_LIST_HEAD(&hvsk->accept_queue);
+ mutex_init(&hvsk->accept_queue_mutex);
+
+ hvsk->peer_shutdown = 0;
+
+ hvsk->recv.data_len = 0;
+ hvsk->recv.data_offset = 0;
+
+ return sk;
+}
+
+static int hvsock_bind(struct socket *sock, struct sockaddr *addr,
+ int addr_len)
+{
+ struct sockaddr_hv *hv_addr;
+ struct sock *sk;
+ int ret;
+
+ sk = sock->sk;
+
+ if (hvsock_addr_cast(addr, addr_len, &hv_addr) != 0)
+ return -EINVAL;
+
+ lock_sock(sk);
+ ret = __hvsock_bind(sk, hv_addr);
+ release_sock(sk);
+
+ return ret;
+}
+
+static int hvsock_getname(struct socket *sock,
+ struct sockaddr *addr, int *addr_len, int peer)
+{
+ struct sockaddr_hv *hv_addr;
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+ int ret;
+
+ sk = sock->sk;
+ hvsk = sk_to_hvsock(sk);
+ ret = 0;
+
+ lock_sock(sk);
+
+ if (peer) {
+ if (sock->state != SS_CONNECTED) {
+ ret = -ENOTCONN;
+ goto out;
+ }
+ hv_addr = &hvsk->remote_addr;
+ } else {
+ hv_addr = &hvsk->local_addr;
+ }
+
+ __sockaddr_check_size(sizeof(*hv_addr));
+
+ memcpy(addr, hv_addr, sizeof(*hv_addr));
+ *addr_len = sizeof(*hv_addr);
+
+out:
+ release_sock(sk);
+ return ret;
+}
+
+static int hvsock_shutdown(struct socket *sock, int mode)
+{
+ struct sock *sk;
+
+ if (mode < SHUT_RD || mode > SHUT_RDWR)
+ return -EINVAL;
+ /* This maps:
+ * SHUT_RD (0) -> RCV_SHUTDOWN (1)
+ * SHUT_WR (1) -> SEND_SHUTDOWN (2)
+ * SHUT_RDWR (2) -> SHUTDOWN_MASK (3)
+ */
+ ++mode;
+
+ if (sock->state == SS_UNCONNECTED)
+ return -ENOTCONN;
+
+ sock->state = SS_DISCONNECTING;
+
+ sk = sock->sk;
+
+ lock_sock(sk);
+
+ sk->sk_shutdown |= mode;
+ sk->sk_state_change(sk);
+
+ /* TODO: how to send a FIN if we haven't done that? */
+ if (mode & SEND_SHUTDOWN)
+ ;
+
+ release_sock(sk);
+
+ return 0;
+}
+
+static void get_ringbuffer_rw_status(struct vmbus_channel *channel,
+ bool *can_read, bool *can_write)
+{
+ u32 avl_read_bytes, avl_write_bytes, dummy;
+
+ if (can_read) {
+ hv_get_ringbuffer_availbytes(&channel->inbound,
+ &avl_read_bytes,
+ &dummy);
+ *can_read = avl_read_bytes >= HVSOCK_MIN_PKT_LEN;
+ }
+
+ /* We write into the ringbuffer only when we're able to write a
+ * a payload of 4096 bytes (the actual written payload's length may be
+ * less than 4096).
+ */
+ if (can_write) {
+ hv_get_ringbuffer_availbytes(&channel->outbound,
+ &dummy,
+ &avl_write_bytes);
+ *can_write = avl_write_bytes > HVSOCK_PKT_LEN(PAGE_SIZE);
+ }
+}
+
+static unsigned int hvsock_poll(struct file *file, struct socket *sock,
+ poll_table *wait)
+{
+ struct vmbus_channel *channel;
+ bool can_read, can_write;
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+ unsigned int mask;
+
+ sk = sock->sk;
+ hvsk = sk_to_hvsock(sk);
+
+ poll_wait(file, sk_sleep(sk), wait);
+ mask = 0;
+
+ if (sk->sk_err)
+ /* Signify that there has been an error on this socket. */
+ mask |= POLLERR;
+
+ /* INET sockets treat local write shutdown and peer write shutdown as a
+ * case of POLLHUP set.
+ */
+ if ((sk->sk_shutdown == SHUTDOWN_MASK) ||
+ ((sk->sk_shutdown & SEND_SHUTDOWN) &&
+ (hvsk->peer_shutdown & SEND_SHUTDOWN))) {
+ mask |= POLLHUP;
+ }
+
+ if (sk->sk_shutdown & RCV_SHUTDOWN ||
+ hvsk->peer_shutdown & SEND_SHUTDOWN) {
+ mask |= POLLRDHUP;
+ }
+
+ lock_sock(sk);
+
+ /* Listening sockets that have connections in their accept
+ * queue can be read.
+ */
+ if (sk->sk_state == SS_LISTEN && !hvsock_is_accept_queue_empty(sk))
+ mask |= POLLIN | POLLRDNORM;
+
+ /* The mutex is to against hvsock_open_connection() */
+ mutex_lock(&hvsock_mutex);
+
+ channel = hvsk->channel;
+ if (channel) {
+ /* If there is something in the queue then we can read */
+ get_ringbuffer_rw_status(channel, &can_read, &can_write);
+
+ if (!can_read && hvsk->recv.data_len > 0)
+ can_read = true;
+
+ if (!(sk->sk_shutdown & RCV_SHUTDOWN) && can_read)
+ mask |= POLLIN | POLLRDNORM;
+ } else {
+ can_read = false;
+ can_write = false;
+ }
+
+ mutex_unlock(&hvsock_mutex);
+
+ /* Sockets whose connections have been closed terminated should
+ * also be considered read, and we check the shutdown flag for that.
+ */
+ if (sk->sk_shutdown & RCV_SHUTDOWN ||
+ hvsk->peer_shutdown & SEND_SHUTDOWN) {
+ mask |= POLLIN | POLLRDNORM;
+ }
+
+ /* Connected sockets that can produce data can be written. */
+ if (sk->sk_state == SS_CONNECTED && can_write &&
+ !(sk->sk_shutdown & SEND_SHUTDOWN)) {
+ /* Remove POLLWRBAND since INET sockets are not setting it.
+ */
+ mask |= POLLOUT | POLLWRNORM;
+ }
+
+ /* Simulate INET socket poll behaviors, which sets
+ * POLLOUT|POLLWRNORM when peer is closed and nothing to read,
+ * but local send is not shutdown.
+ */
+ if (sk->sk_state == SS_UNCONNECTED &&
+ !(sk->sk_shutdown & SEND_SHUTDOWN))
+ mask |= POLLOUT | POLLWRNORM;
+
+ release_sock(sk);
+
+ return mask;
+}
+
+/* This function runs in the tasklet context of process_chn_event() */
+static void hvsock_on_channel_cb(void *ctx)
+{
+ struct sock *sk = (struct sock *)ctx;
+ struct hvsock_sock *hvsk = sk_to_hvsock(sk);
+ struct vmbus_channel *channel = hvsk->channel;
+ bool can_read, can_write;
+
+ if (!channel) {
+ WARN_ONCE(1, "NULL channel! There is a programming bug.\n");
+ return;
+ }
+
+ get_ringbuffer_rw_status(channel, &can_read, &can_write);
+
+ if (can_read)
+ sk->sk_data_ready(sk);
+
+ if (can_write)
+ sk->sk_write_space(sk);
+}
+
+static void hvsock_close_connection(struct vmbus_channel *channel)
+{
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ mutex_lock(&hvsock_mutex);
+
+ sk = __hvsock_find_connected_socket_by_channel(channel);
+
+ /* The guest has already closed the connection? */
+ if (!sk)
+ goto out;
+
+ sk->sk_socket->state = SS_UNCONNECTED;
+ sk->sk_state = SS_UNCONNECTED;
+ sock_set_flag(sk, SOCK_DONE);
+
+ hvsk = sk_to_hvsock(sk);
+ hvsk->peer_shutdown |= SEND_SHUTDOWN | RCV_SHUTDOWN;
+
+ sk->sk_state_change(sk);
+out:
+ mutex_unlock(&hvsock_mutex);
+}
+
+static int hvsock_open_connection(struct vmbus_channel *channel)
+{
+ struct hvsock_sock *hvsk, *new_hvsk;
+ struct sockaddr_hv hv_addr;
+ struct sock *sk, *new_sk;
+
+ uuid_le *instance, *service_id;
+ int ret;
+
+ instance = &channel->offermsg.offer.if_instance;
+ service_id = &channel->offermsg.offer.if_type;
+
+ hvsock_addr_init(&hv_addr, *instance);
+
+ mutex_lock(&hvsock_mutex);
+
+ sk = __hvsock_find_bound_socket(&hv_addr);
+
+ if (sk) {
+ /* It is from the guest client's connect() */
+ if (sk->sk_state != SS_CONNECTING) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ hvsk = sk_to_hvsock(sk);
+ hvsk->channel = channel;
+ set_channel_read_state(channel, false);
+ vmbus_set_chn_rescind_callback(channel,
+ hvsock_close_connection);
+ ret = vmbus_open(channel, VMBUS_RINGBUFFER_SIZE_HVSOCK_SEND,
+ VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV, NULL, 0,
+ hvsock_on_channel_cb, sk);
+ if (ret != 0) {
+ hvsk->channel = NULL;
+ goto out;
+ }
+
+ set_channel_pending_send_size(channel,
+ HVSOCK_PKT_LEN(PAGE_SIZE));
+ sk->sk_state = SS_CONNECTED;
+ sk->sk_socket->state = SS_CONNECTED;
+ hvsock_insert_connected(hvsk);
+ sk->sk_state_change(sk);
+ goto out;
+ }
+
+ /* Now we suppose it is from a host client's connect() */
+ hvsock_addr_init(&hv_addr, *service_id);
+ sk = __hvsock_find_bound_socket(&hv_addr);
+
+ /* No guest server listening? Well, let's ignore the offer */
+ if (!sk || sk->sk_state != SS_LISTEN) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog) {
+ ret = -EMFILE;
+ goto out;
+ }
+
+ new_sk = __hvsock_create(sock_net(sk), NULL, GFP_KERNEL, sk->sk_type);
+ if (!new_sk) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ new_hvsk = sk_to_hvsock(new_sk);
+ new_sk->sk_state = SS_CONNECTING;
+ hvsock_addr_init(&new_hvsk->local_addr, *service_id);
+ hvsock_addr_init(&new_hvsk->remote_addr, *instance);
+
+ set_channel_read_state(channel, false);
+ new_hvsk->channel = channel;
+ vmbus_set_chn_rescind_callback(channel, hvsock_close_connection);
+ ret = vmbus_open(channel, VMBUS_RINGBUFFER_SIZE_HVSOCK_SEND,
+ VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV, NULL, 0,
+ hvsock_on_channel_cb, new_sk);
+ if (ret != 0) {
+ new_hvsk->channel = NULL;
+ sock_put(new_sk);
+ goto out;
+ }
+ set_channel_pending_send_size(channel, HVSOCK_PKT_LEN(PAGE_SIZE));
+
+ new_sk->sk_state = SS_CONNECTED;
+ hvsock_insert_connected(new_hvsk);
+ hvsock_enqueue_accept(sk, new_sk);
+ sk->sk_state_change(sk);
+out:
+ mutex_unlock(&hvsock_mutex);
+ return ret;
+}
+
+static void hvsock_connect_timeout(struct work_struct *work)
+{
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ hvsk = container_of(work, struct hvsock_sock, dwork.work);
+ sk = hvsock_to_sk(hvsk);
+
+ lock_sock(sk);
+ if ((sk->sk_state == SS_CONNECTING) &&
+ (sk->sk_shutdown != SHUTDOWN_MASK)) {
+ sk->sk_state = SS_UNCONNECTED;
+ sk->sk_err = ETIMEDOUT;
+ sk->sk_error_report(sk);
+ }
+ release_sock(sk);
+
+ sock_put(sk);
+}
+
+static int hvsock_connect(struct socket *sock, struct sockaddr *addr,
+ int addr_len, int flags)
+{
+ struct sockaddr_hv *remote_addr;
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ DEFINE_WAIT(wait);
+ long timeout;
+
+ int ret = 0;
+
+ sk = sock->sk;
+ hvsk = sk_to_hvsock(sk);
+
+ lock_sock(sk);
+
+ switch (sock->state) {
+ case SS_CONNECTED:
+ ret = -EISCONN;
+ goto out;
+ case SS_DISCONNECTING:
+ ret = -EINVAL;
+ goto out;
+ case SS_CONNECTING:
+ /* This continues on so we can move sock into the SS_CONNECTED
+ * state once the connection has completed (at which point err
+ * will be set to zero also). Otherwise, we will either wait
+ * for the connection or return -EALREADY should this be a
+ * non-blocking call.
+ */
+ ret = -EALREADY;
+ break;
+ default:
+ if ((sk->sk_state == SS_LISTEN) ||
+ hvsock_addr_cast(addr, addr_len, &remote_addr) != 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Set the remote address that we are connecting to. */
+ memcpy(&hvsk->remote_addr, remote_addr,
+ sizeof(hvsk->remote_addr));
+
+ ret = hvsock_auto_bind(hvsk);
+ if (ret)
+ goto out;
+
+ sk->sk_state = SS_CONNECTING;
+
+ ret = vmbus_send_tl_connect_request(
+ &hvsk->local_addr.shv_service_id,
+ &hvsk->remote_addr.shv_service_id);
+ if (ret < 0)
+ goto out;
+
+ /* Mark sock as connecting and set the error code to in
+ * progress in case this is a non-blocking connect.
+ */
+ sock->state = SS_CONNECTING;
+ ret = -EINPROGRESS;
+ }
+

CAA Putting the connection wait into a separate function if possible would look cleaner.
Checkout llc/af_llc.c
+ /* The receive path will handle all communication until we are able to
+ * enter the connected state. Here we wait for the connection to be
+ * completed or a notification of an error.
+ */
+ timeout = 30 * HZ;
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+
+ while (sk->sk_state != SS_CONNECTED && sk->sk_err == 0) {
+ if (flags & O_NONBLOCK) {
+ /* If we're not going to block, we schedule a timeout
+ * function to generate a timeout on the connection
+ * attempt, in case the peer doesn't respond in a
+ * timely manner. We hold on to the socket until the
+ * timeout fires.
+ */
+ sock_hold(sk);
+ INIT_DELAYED_WORK(&hvsk->dwork,
+ hvsock_connect_timeout);
+ schedule_delayed_work(&hvsk->dwork, timeout);
+
+ /* Skip ahead to preserve error code set above. */
+ goto out_wait;
+ }
+
+ release_sock(sk);
+ timeout = schedule_timeout(timeout);
+ lock_sock(sk);
+
+ if (signal_pending(current)) {
+ ret = sock_intr_errno(timeout);
+ goto out_wait_error;
+ } else if (timeout == 0) {
+ ret = -ETIMEDOUT;
+ goto out_wait_error;
+ }
+
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+ }
+
+ ret = sk->sk_err ? -sk->sk_err : 0;
+
+out_wait_error:
+ if (ret < 0) {
+ sk->sk_state = SS_UNCONNECTED;
+ sock->state = SS_UNCONNECTED;
+ }
+out_wait:
+ finish_wait(sk_sleep(sk), &wait);
+out:
+ release_sock(sk);
+ return ret;
+}
+
+static
+int hvsock_accept(struct socket *sock, struct socket *newsock, int flags)
+{
+ struct hvsock_sock *hvconnected;
+ struct sock *connected;
+ struct sock *listener;
+
+ DEFINE_WAIT(wait);
+ long timeout;
+
+ int ret = 0;
+
+ listener = sock->sk;
+
+ lock_sock(listener);
+
+ if (sock->type != SOCK_STREAM) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ if (listener->sk_state != SS_LISTEN) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Wait for children sockets to appear; these are the new sockets
+ * created upon connection establishment.
+ */
+ timeout = sock_sndtimeo(listener, flags & O_NONBLOCK);
CAA cleaner if wait in a separate function
+ prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
+
+ while ((connected = hvsock_dequeue_accept(listener)) == NULL &&
+ listener->sk_err == 0) {
+ release_sock(listener);
+ timeout = schedule_timeout(timeout);
+ lock_sock(listener);
+
+ if (signal_pending(current)) {
+ ret = sock_intr_errno(timeout);
+ goto out_wait;
+ } else if (timeout == 0) {
+ ret = -EAGAIN;
+ goto out_wait;
+ }
+
+ prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE);
+ }
+
+ if (listener->sk_err)
+ ret = -listener->sk_err;
+
+ if (connected) {
+ lock_sock(connected);
+ hvconnected = sk_to_hvsock(connected);
+
+ /* If the listener socket has received an error, then we should
+ * reject this socket and return. Note that we simply mark the
+ * socket rejected, drop our reference, and let the cleanup
+ * function handle the cleanup; the fact that we found it in
+ * the listener's accept queue guarantees that the cleanup
+ * function hasn't run yet.
+ */
+ if (ret) {
+ release_sock(connected);
+ sock_put(connected);
+ goto out_wait;
+ }
+
+ newsock->state = SS_CONNECTED;
+ sock_graft(connected, newsock);
+ release_sock(connected);
+ sock_put(connected);
+ }
+
+out_wait:
+ finish_wait(sk_sleep(listener), &wait);
+out:
+ release_sock(listener);
+ return ret;
+}
+
+static int hvsock_listen(struct socket *sock, int backlog)
+{
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+ int ret = 0;
+
+ sk = sock->sk;
+ lock_sock(sk);
+
+ if (sock->type != SOCK_STREAM) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ if (sock->state != SS_UNCONNECTED) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (backlog <= 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+ /* This is an artificial limit */
+ if (backlog > 128)
+ backlog = 128;
+
+ hvsk = sk_to_hvsock(sk);
+ if (!hvsock_addr_bound(&hvsk->local_addr)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ sk->sk_ack_backlog = 0;
+ sk->sk_max_ack_backlog = backlog;
+ sk->sk_state = SS_LISTEN;
+out:
+ release_sock(sk);
+ return ret;
+}
+
CAA why don't you set .setsockopt and getsockopt to sock_no_setsockopt and sock_no_getsockopt
+static int hvsock_setsockopt(struct socket *sock,
+ int level,
+ int optname,
+ char __user *optval, unsigned int optlen)
+{
+ return -ENOPROTOOPT;
+}
+
+static int hvsock_getsockopt(struct socket *sock,
+ int level,
+ int optname,
+ char __user *optval, int __user *optlen)
+{
+ return -ENOPROTOOPT;
+}
+
+static int hvsock_send_data(struct vmbus_channel *channel,
+ struct hvsock_sock *hvsk,
+ size_t to_write)
+{
+ hvsk->send.hdr.pkt_type = 1;
+ hvsk->send.hdr.data_size = to_write;
+ return vmbus_sendpacket(channel, &hvsk->send.hdr,
+ sizeof(hvsk->send.hdr) + to_write,
+ 0, VM_PKT_DATA_INBAND, 0);
+}
+
+static int hvsock_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
+{
CAA Again compartmentalize this a bit if possible. example llc/af_llc.c
+ struct vmbus_channel *channel;
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ size_t total_to_write = len;
+ size_t total_written = 0;
+
+ bool can_write;
+ long timeout;
+ int ret = 0;
+
+ DEFINE_WAIT(wait);
+
+ if (len == 0)
+ return -EINVAL;
+
+ if (msg->msg_flags & ~MSG_DONTWAIT) {
+ pr_err("%s: unsupported flags=0x%x\n", __func__,
+ msg->msg_flags);
+ return -EOPNOTSUPP;
+ }
+
+ sk = sock->sk;
+ hvsk = sk_to_hvsock(sk);
+ channel = hvsk->channel;
+
+ lock_sock(sk);
+
+ /* Callers should not provide a destination with stream sockets. */
+ if (msg->msg_namelen) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ /* Send data only if both sides are not shutdown in the direction. */
+ if (sk->sk_shutdown & SEND_SHUTDOWN ||
+ hvsk->peer_shutdown & RCV_SHUTDOWN) {
+ ret = -EPIPE;
+ goto out;
+ }
+
+ if (sk->sk_state != SS_CONNECTED ||
+ !hvsock_addr_bound(&hvsk->local_addr)) {
+ ret = -ENOTCONN;
+ goto out;
+ }
+
+ if (!hvsock_addr_bound(&hvsk->remote_addr)) {
+ ret = -EDESTADDRREQ;
+ goto out;
+ }
+
+ timeout = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+
+ while (total_to_write > 0) {
+ size_t to_write;
+
+ while (1) {
+ get_ringbuffer_rw_status(channel, NULL, &can_write);
+
+ if (can_write || sk->sk_err != 0 ||
+ (sk->sk_shutdown & SEND_SHUTDOWN) ||
+ (hvsk->peer_shutdown & RCV_SHUTDOWN))
+ break;
+
+ /* Don't wait for non-blocking sockets. */
+ if (timeout == 0) {
+ ret = -EAGAIN;
+ goto out_wait;
+ }
+
+ release_sock(sk);
+
+ timeout = schedule_timeout(timeout);
+
+ lock_sock(sk);
+ if (signal_pending(current)) {
+ ret = sock_intr_errno(timeout);
+ goto out_wait;
+ } else if (timeout == 0) {
+ ret = -EAGAIN;
+ goto out_wait;
+ }
+
+ prepare_to_wait(sk_sleep(sk), &wait,
+ TASK_INTERRUPTIBLE);
+ }
+
+ /* These checks occur both as part of and after the loop
+ * conditional since we need to check before and after
+ * sleeping.
+ */
+ if (sk->sk_err) {
+ ret = -sk->sk_err;
+ goto out_wait;
+ } else if ((sk->sk_shutdown & SEND_SHUTDOWN) ||
+ (hvsk->peer_shutdown & RCV_SHUTDOWN)) {
+ ret = -EPIPE;
+ goto out_wait;
+ }
+
+ /* Note: that write will only write as many bytes as possible
+ * in the ringbuffer. It is the caller's responsibility to
+ * check how many bytes we actually wrote.
+ */
+ do {
+ to_write = min_t(size_t, HVSOCK_SND_BUF_SZ,
+ total_to_write);
+ ret = memcpy_from_msg(hvsk->send.buf, msg, to_write);
+ if (ret != 0)
+ goto out_wait;
+
+ ret = hvsock_send_data(channel, hvsk, to_write);
+ if (ret != 0)
+ goto out_wait;
+
+ total_written += to_write;
+ total_to_write -= to_write;
+ } while (total_to_write > 0);
+ }
+out_wait:
+ if (total_written > 0)
+ ret = total_written;
+
+ finish_wait(sk_sleep(sk), &wait);
+out:
+ release_sock(sk);
+
+ /* ret is a bigger-than-0 total_written or a negative err code. */
+ if (ret == 0) {
+ WARN(1, "unexpected return value of 0\n");
+ ret = -EIO;
+ }
+
+ return ret;
+}
+
+static int hvsock_recv_data(struct vmbus_channel *channel,
+ struct hvsock_sock *hvsk,
+ size_t *payload_len)
+{
+ u32 buffer_actual_len;
+ u64 dummy_req_id;
+ int ret;
+
+ ret = vmbus_recvpacket(channel, &hvsk->recv.hdr,
+ sizeof(hvsk->recv.hdr) + sizeof(hvsk->recv.buf),
+ &buffer_actual_len, &dummy_req_id);
+ if (ret != 0 || buffer_actual_len <= sizeof(hvsk->recv.hdr))
+ *payload_len = 0;
+ else
+ *payload_len = hvsk->recv.hdr.data_size;
+
+ return ret;
+}
+
+static int hvsock_recvmsg(struct socket *sock, struct msghdr *msg,
+ size_t len, int flags)
+{
+ struct vmbus_channel *channel;
+ struct hvsock_sock *hvsk;
+ struct sock *sk;
+
+ size_t total_to_read = len;
+ size_t copied;
+
+ bool can_read;
+ long timeout;
+
+ int ret = 0;
+
+ DEFINE_WAIT(wait);
+
+ sk = sock->sk;
+ hvsk = sk_to_hvsock(sk);
+ channel = hvsk->channel;
+
+ lock_sock(sk);
+
+ if (sk->sk_state != SS_CONNECTED) {
+ /* Recvmsg is supposed to return 0 if a peer performs an
+ * orderly shutdown. Differentiate between that case and when a
+ * peer has not connected or a local shutdown occurred with the
+ * SOCK_DONE flag.
+ */
+ if (sock_flag(sk, SOCK_DONE))
+ ret = 0;
+ else
+ ret = -ENOTCONN;
+
+ goto out;
+ }
+
+ /* We ignore msg->addr_name/len. */
+ if (flags & ~MSG_DONTWAIT) {
+ pr_err("%s: unsupported flags=0x%x\n", __func__, flags);
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ /* We don't check peer_shutdown flag here since peer may actually shut
+ * down, but there can be data in the queue that a local socket can
+ * receive.
+ */
+ if (sk->sk_shutdown & RCV_SHUTDOWN) {
+ ret = 0;
+ goto out;
+ }
+
+ /* It is valid on Linux to pass in a zero-length receive buffer. This
+ * is not an error. We may as well bail out now.
+ */
+ if (!len) {
+ ret = 0;
+ goto out;
+ }
+
+ timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+ copied = 0;
+
+ prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
+
+ while (1) {
+ bool need_refill = hvsk->recv.data_len == 0;
+
+ if (need_refill)
+ get_ringbuffer_rw_status(channel, &can_read, NULL);
+ else
+ can_read = true;
+
+ if (can_read) {
+ size_t payload_len;
+
+ if (need_refill) {
+ ret = hvsock_recv_data(channel, hvsk,
+ &payload_len);
+ if (ret != 0 || payload_len == 0 ||
+ payload_len > HVSOCK_RCV_BUF_SZ) {
+ ret = -EIO;
+ goto out_wait;
+ }
+
+ hvsk->recv.data_len = payload_len;
+ hvsk->recv.data_offset = 0;
+ }
+
+ if (hvsk->recv.data_len <= total_to_read) {
+ ret = memcpy_to_msg(msg, hvsk->recv.buf +
+ hvsk->recv.data_offset,
+ hvsk->recv.data_len);
+ if (ret != 0)
+ break;
+
+ copied += hvsk->recv.data_len;
+ total_to_read -= hvsk->recv.data_len;
+ hvsk->recv.data_len = 0;
+ hvsk->recv.data_offset = 0;
+
+ if (total_to_read == 0)
+ break;
+ } else {
+ ret = memcpy_to_msg(msg, hvsk->recv.buf +
+ hvsk->recv.data_offset,
+ total_to_read);
+ if (ret != 0)
+ break;
+
+ copied += total_to_read;
+ hvsk->recv.data_len -= total_to_read;
+ hvsk->recv.data_offset += total_to_read;
+ total_to_read = 0;
+ break;
+ }
+ } else {
+ if (sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN) ||
+ (hvsk->peer_shutdown & SEND_SHUTDOWN))
+ break;
+
+ /* Don't wait for non-blocking sockets. */
+ if (timeout == 0) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ if (copied > 0)
+ break;
+
+ release_sock(sk);
+ timeout = schedule_timeout(timeout);
+ lock_sock(sk);
+
+ if (signal_pending(current)) {
+ ret = sock_intr_errno(timeout);
+ break;
+ } else if (timeout == 0) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ prepare_to_wait(sk_sleep(sk), &wait,
+ TASK_INTERRUPTIBLE);
+ }
+ }
+
+ if (sk->sk_err)
+ ret = -sk->sk_err;
+ else if (sk->sk_shutdown & RCV_SHUTDOWN)
+ ret = 0;
+
+ if (copied > 0) {
+ ret = copied;
+
+ /* If the other side has shutdown for sending and there
+ * is nothing more to read, then we modify the socket
+ * state.
+ */
+ if ((hvsk->peer_shutdown & SEND_SHUTDOWN) &&
+ hvsk->recv.data_len == 0) {
+ get_ringbuffer_rw_status(channel, &can_read, NULL);
+ if (!can_read) {
+ sk->sk_state = SS_UNCONNECTED;
+ sock_set_flag(sk, SOCK_DONE);
+ sk->sk_state_change(sk);
+ }
+ }
+ }
+out_wait:
+ finish_wait(sk_sleep(sk), &wait);
+out:
+ release_sock(sk);
+ return ret;
+}
+
+static const struct proto_ops hvsock_ops = {
+ .family = PF_HYPERV,
+ .owner = THIS_MODULE,
+ .release = hvsock_release,
+ .bind = hvsock_bind,
+ .connect = hvsock_connect,
+ .socketpair = sock_no_socketpair,
+ .accept = hvsock_accept,
+ .getname = hvsock_getname,
+ .poll = hvsock_poll,
+ .ioctl = sock_no_ioctl,
+ .listen = hvsock_listen,
+ .shutdown = hvsock_shutdown,
+ .setsockopt = hvsock_setsockopt,
+ .getsockopt = hvsock_getsockopt,
+ .sendmsg = hvsock_sendmsg,
+ .recvmsg = hvsock_recvmsg,
+ .mmap = sock_no_mmap,
+ .sendpage = sock_no_sendpage,
+};
+
+static int hvsock_create(struct net *net, struct socket *sock,
+ int protocol, int kern)
+{
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN))
+ return -EPERM;
+
+ if (protocol != 0 && protocol != SHV_PROTO_RAW)
+ return -EPROTONOSUPPORT;
+
+ switch (sock->type) {
+ case SOCK_STREAM:
+ sock->ops = &hvsock_ops;
+ break;
+ default:
+ return -ESOCKTNOSUPPORT;
+ }
+
+ sock->state = SS_UNCONNECTED;
+
+ return __hvsock_create(net, sock, GFP_KERNEL, 0) ? 0 : -ENOMEM;
+}
+
+static const struct net_proto_family hvsock_family_ops = {
+ .family = AF_HYPERV,
+ .create = hvsock_create,
+ .owner = THIS_MODULE,
+};
+
+static int hvsock_probe(struct hv_device *hdev,
+ const struct hv_vmbus_device_id *dev_id)
+{
+ struct vmbus_channel *channel = hdev->channel;
+
+ /* We ignore the error return code to suppress the unnecessary
+ * error message in vmbus_probe(): on error the host will rescind
+ * the offer in 30 seconds and we can do cleanup at that time.
+ */
+ (void)hvsock_open_connection(channel);
+
+ return 0;
+}
+
+static int hvsock_remove(struct hv_device *hdev)
+{
+ struct vmbus_channel *channel = hdev->channel;
+
+ vmbus_close(channel);
+
+ return 0;
+}
+
+/* It's not really used. See vmbus_match() and vmbus_probe(). */
+static const struct hv_vmbus_device_id id_table[] = {
+ {},
+};
+
+static struct hv_driver hvsock_drv = {
+ .name = "hv_sock",
+ .hvsock = true,
+ .id_table = id_table,
+ .probe = hvsock_probe,
+ .remove = hvsock_remove,
+};
+
+static int __init hvsock_init(void)+{
+ int ret;
+
+ /* Hyper-V Sockets requires at least VMBus 4.0 */
+ if ((vmbus_proto_version >> 16) < 4) {
+ pr_err("failed to load: VMBus 4 or later is required\n");
+ return -ENODEV;
+ }
+
+ ret = vmbus_driver_register(&hvsock_drv);
+ if (ret) {
+ pr_err("failed to register hv_sock driver\n");
+ return ret;
+ }
+
+ ret = proto_register(&hvsock_proto, 0);
+ if (ret) {
+ pr_err("failed to register protocol\n");
+ goto unreg_hvsock_drv;
+ }
+
+ ret = sock_register(&hvsock_family_ops);
+ if (ret) {
+ pr_err("failed to register address family\n");
+ goto unreg_proto;
+ }
+
+ return 0;
+
+unreg_proto:
+ proto_unregister(&hvsock_proto);
+unreg_hvsock_drv:
+ vmbus_driver_unregister(&hvsock_drv);
+ return ret;
+}
+
+static void __exit hvsock_exit(void)+{
+ sock_unregister(AF_HYPERV);
+ proto_unregister(&hvsock_proto);
+ vmbus_driver_unregister(&hvsock_drv);
+}
+
+module_init(hvsock_init);
+module_exit(hvsock_exit);
+
+MODULE_DESCRIPTION("Hyper-V Sockets");
+MODULE_LICENSE("Dual BSD/GPL");