Dexuan Cui <de...@microsoft.com> writes: > 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>
Some comments below. The vast majority of them are really minor, the only thing which bothers me a little bit is WARN() in hvsock_sendmsg() which I think shouldn't be there. But I may have missed something. I didn't do any tests for the code. > Cc: Cathy Avery <cav...@redhat.com> > --- > > You can also get the patch here (2764221d): > https://github.com/dcui/linux/commits/decui/hv_sock/net-next/20160708_v15 > > 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. > > 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 | 24 + > net/Kconfig | 1 + > net/Makefile | 1 + > net/hv_sock/Kconfig | 10 + > net/hv_sock/Makefile | 3 + > net/hv_sock/af_hvsock.c | 1523 > +++++++++++++++++++++++++++++++++++++++++++ > 10 files changed, 1658 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..d942996 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 +397,27 @@ 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 > + */ > +#define guid_t uuid_le > +struct sockaddr_hv { > + __kernel_sa_family_t shv_family; /* Address family */ > + u16 reserved; /* Must be Zero */ > + guid_t shv_vm_id; /* VM ID */ > + guid_t shv_service_id; /* Service ID */ > +}; (sorry if it was already discussed before and I missed it) I'm not sure it is worth it to introduce a new 'guid_t' type here, we may want to rename shv_vm_id -> shv_vm_guid shv_service_id -> shv_service_guid and use uuid_le type. > + > +#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..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. > + I know it's hard to come up with a simple description but I'd rather describe is as "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..f339f38 > --- /dev/null > +++ b/net/hv_sock/af_hvsock.c > @@ -0,0 +1,1523 @@ > +/* > + * 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 > + > +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); > +} why not use uuid_le_cmp directly? > + > +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 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_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; > + > + 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); > + > + 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_equals(hv_addr->shv_vm_id, 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); > + } > +} > + > +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_read = false; we don't use can_read below > + 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; > + if (!channel) { > + WARN_ONCE(1, "NULL channel! There is a programming bug.\n"); BUG() then > + 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_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; > + uuid_le *instance, *service_id; > + unsigned char conn_from_host; > + struct sockaddr_hv hv_addr; > + struct sock *sk, *new_sk; > + 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 = -EMFILE; I'm not sure -EMFILE is appropriate, we don't really have "too many open files". > + 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) + 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 = 30 * HZ; We may want to introduce a define for this timeout. Does it actually match host's 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_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; > + } > + > + 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) { > + release_sock(connected); > + sock_put(connected); > + } else { > + newsock->state = SS_CONNECTED; > + sock_graft(connected, newsock); > + release_sock(connected); > + sock_put(connected); so we do release_sock()/sock_put() unconditionally and this piece could be rewritten as 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; > + } > + /* This is an artificial limit */ > + if (backlog > 128) > + backlog = 128; Let's do a define for it. > + > + 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 = 0; > + > + 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) { > + pr_err("%s: unsupported flags=0x%x\n", __func__, > + msg->msg_flags); I don't think we need pr_err() here. > + 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 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; > + } It seems hvsock_sendmsg_wait() can return 0. I see the following code there: max_writable = get_ringbuffer_writable_bytes(channel); if (max_writable == 0) goto out_wait; so if there is no space on the ringbuffer we won't write anything. WARN() is inapropriate then. > + > + 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) { > + pr_err("%s: unsupported flags=0x%x\n", __func__, flags); Here he may also want to drop pr_err() > + 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 (!capable(CAP_SYS_ADMIN) && !capable(CAP_NET_ADMIN)) > + return -EPERM; I'd say we're OK with CAP_SYS_ADMIN only for now and we'll be able to drop the check when host starts supporting single pair of ringbuffers for all Hyper-V sockets on the system. > + > + 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; > + > + /* Hyper-V Sockets requires at least VMBus 4.0 */ > + if ((vmbus_proto_version >> 16) < 4) > + return -ENODEV; So it's actually if (vmbus_proto_version < VERSION_WIN10) I suggest we use such comparisson to be in line with other places where vmbus_proto_version is checked. > + > + 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"); -- Vitaly _______________________________________________ devel mailing list de...@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
