[PATCH v9 net-next 0/2] introduce Hyper-V VM Sockets(hv_sock)

From: Dexuan Cui
Date: Wed May 04 2016 - 11:21:48 EST

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":

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

You can also get the patch by:

Note: the VMBus driver side's supporting patches have been in the mainline

I know the kernel has already had a VM Sockets driver (AF_VSOCK) based
on VMware VMCI (net/vmw_vsock/, drivers/misc/vmw_vmci), and KVM is
proposing AF_VSOCK of virtio version:

However, though Hyper-V Sockets may seem conceptually similar to
AF_VOSCK, there are differences in the transportation layer, and IMO these
make the direct code reusing impractical:

1. In AF_VSOCK, the endpoint type is: <u32 ContextID, u32 Port>, but in
AF_HYPERV, the endpoint type is: <GUID VM_ID, GUID ServiceID>. Here GUID
is 128-bit.

2. AF_VSOCK supports SOCK_DGRAM, while AF_HYPERV doesn't.

3. AF_VSOCK supports some special sock opts, like SO_VM_SOCKETS_BUFFER_SIZE,
These are meaningless to AF_HYPERV.

4. Some AF_VSOCK's VMCI transportation ops are meanless to AF_HYPERV/VMBus,
like .notify_recv_init

So I think we'd better introduce a new address family: AF_HYPERV.

Please review the patch.

Looking forward to your comments, especially comments from David. :-)

Changes since v1:
- updated "[PATCH 6/7] hvsock: introduce Hyper-V VM Sockets feature"
- added __init and __exit for the module init/exit functions
- net/hv_sock/Kconfig: "default m" -> "default m if HYPERV"

Changes since v2:
- fixed various coding issue pointed out by David Miller
- fixed indentation issues
- removed pr_debug in net/hv_sock/af_hvsock.c
- used reverse-Chrismas-tree style for local variables.

Changes since v3:
- fixed a few coding issue pointed by Vitaly Kuznetsov and Dan Carpenter
- fixed the ret value in vmbus_recvpacket_hvsock on error
- fixed the style of multi-line comment: vmbus_get_hvsock_rw_status()

Changes since v4 (https://lkml.org/lkml/2015/7/28/404):
- addressed all the comments about V4.
- treat the hvsock offers/channels as special VMBus devices
- add a mechanism to pass hvsock events to the hvsock driver
- fixed some corner cases with proper locking when a connection is closed
- rebased to the latest Greg's tree

Changes since v5 (https://lkml.org/lkml/2015/12/24/103):
- addressed the coding style issues (Vitaly Kuznetsov & David Miller, thanks!)
- used a better coding for the per-channel rescind callback (Thank Vitaly!)
- avoided the introduction of new VMBUS driver APIs vmbus_sendpacket_hvsock()
and vmbus_recvpacket_hvsock() and used vmbus_sendpacket()/vmbus_recvpacket()
in the higher level (i.e., the vmsock driver). Thank Vitaly!

Changes since v6 (http://lkml.iu.edu/hypermail/linux/kernel/1601.3/01813.html)
- only a few minor changes of coding style and comments

Changes since v7
- a few minor changes of coding style: thanks, Joe Perches!
- added some lines of comments about GUID/UUID before the struct sockaddr_hv.

Changes since v8
- removed the unnecessary __packed for some definitions: thanks, David!
- hvsock_open_connection: use offer.u.pipe.user_def[0] to know the connection
and reorganized the function
- reorganized the code according to suggestions from Cathy Avery: split big
functions into small ones, set .setsockopt and getsockopt to
- inline'd some small list helper functions

Dexuan Cui (2):
hv_sock: introduce Hyper-V Sockets
net: add the AF_HYPERV entries to family name tables

include/linux/hyperv.h | 16 +
include/linux/socket.h | 5 +-
include/net/af_hvsock.h | 55 ++
include/uapi/linux/hyperv.h | 25 +
net/Kconfig | 1 +
net/Makefile | 1 +
net/core/sock.c | 6 +-
net/hv_sock/Kconfig | 10 +
net/hv_sock/Makefile | 3 +
net/hv_sock/af_hvsock.c | 1434 +++++++++++++++++++++++++++++++++++++++++++
11 files changed, 1553 insertions(+), 5 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