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 <de...@microsoft.com> Cc: "K. Y. Srinivasan" <k...@microsoft.com> Cc: Haiyang Zhang <haiya...@microsoft.com> Cc: Vitaly Kuznetsov <vkuzn...@redhat.com> Cc: Cathy Avery <cav...@redhat.com> Cc: Olaf Hering <o...@aepfle.de> --- You can also get the patch by (commit 84146dfb): https://github.com/dcui/linux/commits/decui/hv_sock/net-next/20160721_v18 For the change log before v12, please see https://lkml.org/lkml/2016/5/15/31 In v12, the changes are mainly the following: 1) remove the module params as David suggested. 2) use 5 exact pages for VMBus send/recv rings, respectively. The host side's design of the feature requires 5 exact pages for recv/send rings respectively -- this is suboptimal considering memory consumption, however unluckily we have to live with it, before the host comes up with a new design in the future. :-( 3) remove the per-connection static send/recv buffers Instead, we allocate and free the buffers dynamically only when we recv/send data. This means: when a connection is idle, no memory is consumed as recv/send buffers at all. In v13: I return ENOMEM on buffer alllocation failure Actually "man read/write" says "Other errors may occur, depending on the object connected to fd". "man send/recv" indeed lists ENOMEM. Considering AF_HYPERV is a new socket type, ENOMEM seems OK here. In the long run, I think we should add a new API in the VMBus driver, allowing data copy from VMBus ringbuffer into user mode buffer directly. This way, we can even eliminate this temporary buffer. In v14: fix some coding style issues pointed out by David. In v15: Just some stylistic changes addressing comments from Joe Perches and Olaf Hering -- thank you! - add a GPL blurb. - define a new macro PAGE_SIZE_4K and use it to replace PAGE_SIZE - change sk_to_hvsock/hvsock_to_sk() from macros to inline functions - remove a not-very-useful pr_err() - fix some typos in comment and coding style issues. In v16: Made stylistic changes addressing comments from Vitaly Kuznetsov. Thank you very much for the detailed comments, Vitaly! In v17: - PAGE_SIZE -> PAGE_SIZE_4K - allow regular users to use the socket Thank you Michal Kubecek for the suggestions! In v18: Just some tiny updates to address some spurious compiler warnings: "xxx may be used uninitialized in this function". Looking forward to your comments! MAINTAINERS | 2 + include/linux/hyperv.h | 13 + include/linux/socket.h | 4 +- include/net/af_hvsock.h | 78 +++ include/uapi/linux/hyperv.h | 23 + net/Kconfig | 1 + net/Makefile | 1 + net/hv_sock/Kconfig | 10 + net/hv_sock/Makefile | 3 + net/hv_sock/af_hvsock.c | 1507 +++++++++++++++++++++++++++++++++++++++++++ 10 files changed, 1641 insertions(+), 1 deletion(-) diff --git a/MAINTAINERS b/MAINTAINERS index 50f69ba..6eaa26f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5514,7 +5514,9 @@ 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 50f493e..1cda6ea5 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1508,5 +1508,18 @@ static inline void commit_rd_index(struct vmbus_channel *channel) vmbus_set_event(channel); } +struct vmpipe_proto_header { + u32 pkt_type; + u32 data_size; +}; + +#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) #endif /* _HYPERV_H */ diff --git a/include/linux/socket.h b/include/linux/socket.h index b5cc5a6..0b68b58 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -202,8 +202,9 @@ struct ucred { #define AF_VSOCK 40 /* vSockets */ #define AF_KCM 41 /* Kernel Connection Multiplexor*/ #define AF_QIPCRTR 42 /* Qualcomm IPC Router */ +#define AF_HYPERV 43 /* Hyper-V Sockets */ -#define AF_MAX 43 /* For now.. */ +#define AF_MAX 44 /* For now.. */ /* Protocol families, same as address families. */ #define PF_UNSPEC AF_UNSPEC @@ -251,6 +252,7 @@ struct ucred { #define PF_VSOCK AF_VSOCK #define PF_KCM AF_KCM #define PF_QIPCRTR AF_QIPCRTR +#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..e7a8a3a --- /dev/null +++ b/include/net/af_hvsock.h @@ -0,0 +1,78 @@ +#ifndef __AF_HVSOCK_H__ +#define __AF_HVSOCK_H__ + +#include <linux/kernel.h> +#include <linux/hyperv.h> +#include <net/sock.h> + +/* The host side's design of the feature requires 5 exact 4KB pages for + * recv/send rings respectively -- this is suboptimal considering memory + * consumption, however unluckily we have to live with it, before the + * host comes up with a better design in the future. + */ +#define PAGE_SIZE_4K 4096 +#define RINGBUFFER_HVSOCK_RCV_SIZE (PAGE_SIZE_4K * 5) +#define RINGBUFFER_HVSOCK_SND_SIZE (PAGE_SIZE_4K * 5) + +/* The MTU is 16KB per the host side's design. + * In future, the buffer can be elimiated when we switch to use the coming + * new VMBus ringbuffer "in-place consumption" APIs, by which we can + * directly copy data from VMBus ringbuffer into the userspace buffer. + */ +#define HVSOCK_MTU_SIZE (1024 * 16) +struct hvsock_recv_buf { + unsigned int data_len; + unsigned int data_offset; + + struct vmpipe_proto_header hdr; + u8 buf[HVSOCK_MTU_SIZE]; +}; + +/* In the VM, actually we can send up to HVSOCK_MTU_SIZE bytes of payload, + * but for now let's use a smaller size to minimize the dynamically-allocated + * buffer. Note: the buffer can be elimiated in future when we add new VMBus + * ringbuffer APIs that allow us to directly copy data from userspace buf to + * VMBus ringbuffer. + */ +#define HVSOCK_MAX_SND_SIZE_BY_VM (1024 * 4) +struct hvsock_send_buf { + struct vmpipe_proto_header hdr; + u8 buf[HVSOCK_MAX_SND_SIZE_BY_VM]; +}; + +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 hvsock_send_buf *send; + struct hvsock_recv_buf *recv; +}; + +static inline struct hvsock_sock *sk_to_hvsock(struct sock *sk) +{ + return (struct hvsock_sock *)sk; +} + +static inline struct sock *hvsock_to_sk(struct hvsock_sock *hvsk) +{ + return (struct sock *)hvsk; +} + +#endif /* __AF_HVSOCK_H__ */ diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h index e347b24..eb3e44b 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 +397,26 @@ struct hv_kvp_ip_msg { struct hv_kvp_ipaddr_value kvp_ip_val; } __attribute__((packed)); +/* This is the address format 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 + */ +struct sockaddr_hv { + __kernel_sa_family_t shv_family; /* Address family */ + u16 reserved; /* Must be Zero */ + uuid_le shv_vm_guid; /* VM ID */ + uuid_le shv_service_guid; /* 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 ff40562..0dacc11 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 bdd1455..ec175dd 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..ff84875 --- /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 a socket interface for high speed + communication between Linux guest and Hyper-V host over VMBus. + + 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..331d375 --- /dev/null +++ b/net/hv_sock/af_hvsock.c @@ -0,0 +1,1507 @@ +/* + * 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. + * + * Alternatively, this software may be distributed under the terms of the + * GNU General Public License ("GPL") version 2 as published by the Free + * Software Foundation. + * + * 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 <linux/vmalloc.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 + +#define HVSOCK_CONNECT_TIMEOUT (30 * HZ) + +/* This is an artificial limit */ +#define HVSOCK_MAX_BACKLOG 128 + +static LIST_HEAD(hvsock_bound_list); +static LIST_HEAD(hvsock_connected_list); +static DEFINE_MUTEX(hvsock_mutex); + +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_le_cmp(addr->shv_service_guid, + hvsk->local_addr.shv_service_guid)) + 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 void hvsock_enqueue_accept(struct sock *listener, + struct sock *connected) +{ + struct hvsock_sock *hvconnected; + struct hvsock_sock *hvlistener; + + 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 *hvconnected; + struct hvsock_sock *hvlistener; + + 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_guid = 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; + + return 0; +} + +static bool hvsock_addr_bound(const struct sockaddr_hv *addr) +{ + return !!uuid_le_cmp(addr->shv_service_guid, 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_guid); + + mutex_lock(&hvsock_mutex); + + if (!uuid_le_cmp(addr->shv_service_guid, SHV_SERVICE_ID_ANY)) { + do { + uuid_le_gen(&hv_addr.shv_service_guid); + } 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_guid); + + sock_hold(&hvsk->sk); + list_add(&hvsk->bound_list, &hvsock_bound_list); +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 vmbus_channel *channel; + struct hvsock_sock *hvsk; + + hvsk = sk_to_hvsock(sk); + vfree(hvsk->send); + vfree(hvsk->recv); + + 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 (!list_empty(&hvsk->bound_list)) { + list_del_init(&hvsk->bound_list); + sock_put(&hvsk->sk); + } + + if (!list_empty(&hvsk->connected_list)) { + list_del_init(&hvsk->connected_list); + sock_put(&hvsk->sk); + } + + 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; + + 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); + + hvsk = sk_to_hvsock(sk); + + hvsk->send = NULL; + hvsk->recv = NULL; + + hvsock_addr_init(&hvsk->local_addr, SHV_SERVICE_ID_ANY); + hvsock_addr_init(&hvsk->remote_addr, SHV_SERVICE_ID_ANY); + + 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; + + 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; + + if (uuid_le_cmp(hv_addr->shv_vm_guid, NULL_UUID_LE)) + 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 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); + /* 0-size payload means FIN */ + *can_read = avl_read_bytes >= HVSOCK_PKT_LEN(0); + } + + if (can_write) { + hv_get_ringbuffer_availbytes(&channel->outbound, + &dummy, + &avl_write_bytes); + + /* We only write if there is enough space */ + *can_write = avl_write_bytes > HVSOCK_PKT_LEN(PAGE_SIZE_4K); + } +} + +static size_t get_ringbuffer_writable_bytes(struct vmbus_channel *channel) +{ + u32 avl_write_bytes, dummy; + size_t ret; + + hv_get_ringbuffer_availbytes(&channel->outbound, + &dummy, + &avl_write_bytes); + + /* The ringbuffer mustn't be 100% full, and we should reserve a + * zero-length-payload packet for the FIN: see hv_ringbuffer_write() + * and hvsock_shutdown(). + */ + if (avl_write_bytes < HVSOCK_PKT_LEN(1) + HVSOCK_PKT_LEN(0)) + return 0; + ret = avl_write_bytes - HVSOCK_PKT_LEN(1) - HVSOCK_PKT_LEN(0); + + return round_down(ret, 8); +} + +static int hvsock_get_send_buf(struct hvsock_sock *hvsk) +{ + hvsk->send = vmalloc(sizeof(*hvsk->send)); + return hvsk->send ? 0 : -ENOMEM; +} + +static void hvsock_put_send_buf(struct hvsock_sock *hvsk) +{ + vfree(hvsk->send); + hvsk->send = NULL; +} + +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_get_recv_buf(struct hvsock_sock *hvsk) +{ + hvsk->recv = vmalloc(sizeof(*hvsk->recv)); + return hvsk->recv ? 0 : -ENOMEM; +} + +static void hvsock_put_recv_buf(struct hvsock_sock *hvsk) +{ + vfree(hvsk->recv); + hvsk->recv = NULL; +} + +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_shutdown(struct socket *sock, int mode) +{ + struct hvsock_sock *hvsk; + struct sock *sk; + int ret = 0; + + 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_CONNECTED) + return -ENOTCONN; + + sock->state = SS_DISCONNECTING; + + sk = sock->sk; + + lock_sock(sk); + + sk->sk_shutdown |= mode; + sk->sk_state_change(sk); + + if (mode & SEND_SHUTDOWN) { + hvsk = sk_to_hvsock(sk); + + ret = hvsock_get_send_buf(hvsk); + if (ret < 0) + goto out; + + /* It can't fail: see get_ringbuffer_writable_bytes(). */ + (void)hvsock_send_data(hvsk->channel, hvsk, 0); + + hvsock_put_send_buf(hvsk); + } + +out: + release_sock(sk); + + return ret; +} + +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; + unsigned int mask; + struct sock *sk; + + 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) + can_read = true; + + if (!(sk->sk_shutdown & RCV_SHUTDOWN) && can_read) + mask |= POLLIN | POLLRDNORM; + } else { + 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 vmbus_channel *channel; + struct hvsock_sock *hvsk; + bool can_read, can_write; + + hvsk = sk_to_hvsock(sk); + channel = hvsk->channel; + BUG_ON(!channel); + + 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_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 = NULL, *new_hvsk = NULL; + uuid_le *instance, *service_id; + unsigned char conn_from_host; + struct sockaddr_hv hv_addr; + struct sock *sk, *new_sk = NULL; + int ret; + + instance = &channel->offermsg.offer.if_instance; + service_id = &channel->offermsg.offer.if_type; + + /* The first byte != 0 means the host initiated the connection. */ + conn_from_host = channel->offermsg.offer.u.pipe.user_def[0]; + + mutex_lock(&hvsock_mutex); + + hvsock_addr_init(&hv_addr, conn_from_host ? *service_id : *instance); + sk = hvsock_find_bound_socket(&hv_addr); + + if (!sk || (conn_from_host && sk->sk_state != SS_LISTEN) || + (!conn_from_host && sk->sk_state != SS_CONNECTING)) { + ret = -ENXIO; + goto out; + } + + if (conn_from_host) { + if (sk->sk_ack_backlog >= sk->sk_max_ack_backlog) { + ret = -ECONNREFUSED; + goto out; + } + + new_sk = hvsock_create(sock_net(sk), NULL, GFP_KERNEL, + sk->sk_type); + if (!new_sk) { + ret = -ENOMEM; + goto out; + } + + new_sk->sk_state = SS_CONNECTING; + new_hvsk = sk_to_hvsock(new_sk); + new_hvsk->channel = channel; + hvsock_addr_init(&new_hvsk->local_addr, *service_id); + hvsock_addr_init(&new_hvsk->remote_addr, *instance); + } else { + hvsk = sk_to_hvsock(sk); + hvsk->channel = channel; + } + + set_channel_read_state(channel, false); + ret = vmbus_open(channel, RINGBUFFER_HVSOCK_SND_SIZE, + RINGBUFFER_HVSOCK_RCV_SIZE, NULL, 0, + hvsock_on_channel_cb, conn_from_host ? new_sk : sk); + if (ret != 0) { + if (conn_from_host) { + new_hvsk->channel = NULL; + sock_put(new_sk); + } else { + hvsk->channel = NULL; + } + goto out; + } + + vmbus_set_chn_rescind_callback(channel, hvsock_close_connection); + + /* see get_ringbuffer_rw_status() */ + set_channel_pending_send_size(channel, + HVSOCK_PKT_LEN(PAGE_SIZE_4K) + 1); + + if (conn_from_host) { + new_sk->sk_state = SS_CONNECTED; + + sock_hold(&new_hvsk->sk); + list_add(&new_hvsk->connected_list, &hvsock_connected_list); + + hvsock_enqueue_accept(sk, new_sk); + } else { + sk->sk_state = SS_CONNECTED; + sk->sk_socket->state = SS_CONNECTED; + + sock_hold(&hvsk->sk); + list_add(&hvsk->connected_list, &hvsock_connected_list); + } + + 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_wait(struct socket *sock, + int flags, int current_ret) +{ + struct sock *sk = sock->sk; + struct hvsock_sock *hvsk; + int ret = current_ret; + DEFINE_WAIT(wait); + long timeout; + + hvsk = sk_to_hvsock(sk); + timeout = HVSOCK_CONNECT_TIMEOUT; + 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); + return ret; +} + +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; + 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_guid, + &hvsk->remote_addr.shv_service_guid); + 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; + } + + ret = hvsock_connect_wait(sock, flags, ret); +out: + release_sock(sk); + return ret; +} + +static int hvsock_accept_wait(struct sock *listener, + struct socket *newsock, int flags) +{ + struct hvsock_sock *hvconnected; + struct sock *connected; + + DEFINE_WAIT(wait); + long timeout; + + int ret = 0; + + /* Wait for children sockets to appear; these are the new sockets + * created upon connection establishment. + */ + timeout = sock_sndtimeo(listener, flags & O_NONBLOCK); + 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 (!ret) { + newsock->state = SS_CONNECTED; + sock_graft(connected, newsock); + } + release_sock(connected); + sock_put(connected); + } + +out_wait: + finish_wait(sk_sleep(listener), &wait); + return ret; +} + +static int hvsock_accept(struct socket *sock, struct socket *newsock, + int flags) +{ + struct sock *listener; + int ret; + + 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; + } + + ret = hvsock_accept_wait(listener, newsock, flags); +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; + } + if (backlog > HVSOCK_MAX_BACKLOG) + backlog = HVSOCK_MAX_BACKLOG; + + 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; +} + +static int hvsock_sendmsg_wait(struct sock *sk, struct msghdr *msg, + size_t len) +{ + struct hvsock_sock *hvsk = sk_to_hvsock(sk); + struct vmbus_channel *channel; + size_t total_to_write = len; + size_t total_written = 0; + DEFINE_WAIT(wait); + bool can_write; + long timeout; + int ret = -EIO; + + timeout = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + channel = hvsk->channel; + + while (total_to_write > 0) { + size_t to_write, max_writable; + + 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 { + max_writable = get_ringbuffer_writable_bytes(channel); + if (max_writable == 0) + goto out_wait; + + to_write = min_t(size_t, sizeof(hvsk->send->buf), + total_to_write); + if (to_write > max_writable) + to_write = max_writable; + + ret = hvsock_get_send_buf(hvsk); + if (ret < 0) + goto out_wait; + + ret = memcpy_from_msg(hvsk->send->buf, msg, to_write); + if (ret != 0) { + hvsock_put_send_buf(hvsk); + goto out_wait; + } + + ret = hvsock_send_data(channel, hvsk, to_write); + hvsock_put_send_buf(hvsk); + 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); + return ret; +} + +static int hvsock_sendmsg(struct socket *sock, struct msghdr *msg, + size_t len) +{ + struct hvsock_sock *hvsk; + struct sock *sk; + int ret; + + if (len == 0) + return -EINVAL; + + if (msg->msg_flags & ~MSG_DONTWAIT) + return -EOPNOTSUPP; + + sk = sock->sk; + hvsk = sk_to_hvsock(sk); + + 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; + } + + ret = hvsock_sendmsg_wait(sk, msg, len); +out: + release_sock(sk); + + /* ret should be a bigger-than-0 total_written or a negative err + * code. + */ + BUG_ON(ret == 0); + + return ret; +} + +static int hvsock_recvmsg_wait(struct sock *sk, struct msghdr *msg, + size_t len, int flags) +{ + struct hvsock_sock *hvsk = sk_to_hvsock(sk); + size_t to_read, total_to_read = len; + struct vmbus_channel *channel; + DEFINE_WAIT(wait); + size_t copied = 0; + bool can_read; + long timeout; + int ret = 0; + + timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + channel = hvsk->channel; + + while (1) { + bool need_refill = !hvsk->recv; + + if (need_refill) { + if (hvsk->peer_shutdown & SEND_SHUTDOWN) + can_read = false; + else + get_ringbuffer_rw_status(channel, &can_read, + NULL); + } else { + can_read = true; + } + + if (can_read) { + size_t payload_len; + + if (need_refill) { + ret = hvsock_get_recv_buf(hvsk); + if (ret < 0) { + if (copied > 0) + ret = copied; + goto out_wait; + } + + ret = hvsock_recv_data(channel, hvsk, + &payload_len); + if (ret != 0 || + payload_len > sizeof(hvsk->recv->buf)) { + ret = -EIO; + hvsock_put_recv_buf(hvsk); + goto out_wait; + } + + if (payload_len == 0) { + ret = copied; + hvsock_put_recv_buf(hvsk); + hvsk->peer_shutdown |= SEND_SHUTDOWN; + break; + } + + hvsk->recv->data_len = payload_len; + hvsk->recv->data_offset = 0; + } + + to_read = min_t(size_t, total_to_read, + hvsk->recv->data_len); + + ret = memcpy_to_msg(msg, hvsk->recv->buf + + hvsk->recv->data_offset, + to_read); + if (ret != 0) + break; + + copied += to_read; + total_to_read -= to_read; + + hvsk->recv->data_len -= to_read; + + if (hvsk->recv->data_len == 0) + hvsock_put_recv_buf(hvsk); + else + hvsk->recv->data_offset += to_read; + + if (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; +out_wait: + finish_wait(sk_sleep(sk), &wait); + return ret; +} + +static int hvsock_recvmsg(struct socket *sock, struct msghdr *msg, + size_t len, int flags) +{ + struct sock *sk = sock->sk; + int ret; + + 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) { + 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; + } + + ret = hvsock_recvmsg_wait(sk, msg, len, flags); +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 = sock_no_setsockopt, + .getsockopt = sock_no_getsockopt, + .sendmsg = hvsock_sendmsg, + .recvmsg = hvsock_recvmsg, + .mmap = sock_no_mmap, + .sendpage = sock_no_sendpage, +}; + +static int hvsock_create_sock(struct net *net, struct socket *sock, + int protocol, int kern) +{ + struct sock *sk; + + 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; + + sk = hvsock_create(net, sock, GFP_KERNEL, 0); + return sk ? 0 : -ENOMEM; +} + +static const struct net_proto_family hvsock_family_ops = { + .family = AF_HYPERV, + .create = hvsock_create_sock, + .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; + + if (vmbus_proto_version < VERSION_WIN10) + 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"); -- 2.1.0
