1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
|
/*
* Kernel/userspace transport abstraction for Hyper-V util driver.
*
* Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
*/
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include "hyperv_vmbus.h"
#include "hv_utils_transport.h"
static DEFINE_SPINLOCK(hvt_list_lock);
static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
static void hvt_reset(struct hvutil_transport *hvt)
{
mutex_lock(&hvt->outmsg_lock);
kfree(hvt->outmsg);
hvt->outmsg = NULL;
hvt->outmsg_len = 0;
mutex_unlock(&hvt->outmsg_lock);
if (hvt->on_reset)
hvt->on_reset();
}
static ssize_t hvt_op_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct hvutil_transport *hvt;
int ret;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0))
return -EINTR;
mutex_lock(&hvt->outmsg_lock);
if (!hvt->outmsg) {
ret = -EAGAIN;
goto out_unlock;
}
if (count < hvt->outmsg_len) {
ret = -EINVAL;
goto out_unlock;
}
if (!copy_to_user(buf, hvt->outmsg, hvt->outmsg_len))
ret = hvt->outmsg_len;
else
ret = -EFAULT;
kfree(hvt->outmsg);
hvt->outmsg = NULL;
hvt->outmsg_len = 0;
out_unlock:
mutex_unlock(&hvt->outmsg_lock);
return ret;
}
static ssize_t hvt_op_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct hvutil_transport *hvt;
u8 *inmsg;
int ret;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
inmsg = memdup_user(buf, count);
if (IS_ERR(inmsg))
return PTR_ERR(inmsg);
ret = hvt->on_msg(inmsg, count);
kfree(inmsg);
return ret ? ret : count;
}
static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
{
struct hvutil_transport *hvt;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
poll_wait(file, &hvt->outmsg_q, wait);
if (hvt->outmsg_len > 0)
return POLLIN | POLLRDNORM;
return 0;
}
static int hvt_op_open(struct inode *inode, struct file *file)
{
struct hvutil_transport *hvt;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
/*
* Switching to CHARDEV mode. We switch bach to INIT when device
* gets released.
*/
if (hvt->mode == HVUTIL_TRANSPORT_INIT)
hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
/*
* We're switching from netlink communication to using char
* device. Issue the reset first.
*/
hvt_reset(hvt);
hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
} else
return -EBUSY;
return 0;
}
static int hvt_op_release(struct inode *inode, struct file *file)
{
struct hvutil_transport *hvt;
hvt = container_of(file->f_op, struct hvutil_transport, fops);
hvt->mode = HVUTIL_TRANSPORT_INIT;
/*
* Cleanup message buffers to avoid spurious messages when the daemon
* connects back.
*/
hvt_reset(hvt);
return 0;
}
static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
struct hvutil_transport *hvt, *hvt_found = NULL;
spin_lock(&hvt_list_lock);
list_for_each_entry(hvt, &hvt_list, list) {
if (hvt->cn_id.idx == msg->id.idx &&
hvt->cn_id.val == msg->id.val) {
hvt_found = hvt;
break;
}
}
spin_unlock(&hvt_list_lock);
if (!hvt_found) {
pr_warn("hvt_cn_callback: spurious message received!\n");
return;
}
/*
* Switching to NETLINK mode. Switching to CHARDEV happens when someone
* opens the device.
*/
if (hvt->mode == HVUTIL_TRANSPORT_INIT)
hvt->mode = HVUTIL_TRANSPORT_NETLINK;
if (hvt->mode == HVUTIL_TRANSPORT_NETLINK)
hvt_found->on_msg(msg->data, msg->len);
else
pr_warn("hvt_cn_callback: unexpected netlink message!\n");
}
int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
{
struct cn_msg *cn_msg;
int ret = 0;
if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
return -EINVAL;
} else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
if (!cn_msg)
return -ENOMEM;
cn_msg->id.idx = hvt->cn_id.idx;
cn_msg->id.val = hvt->cn_id.val;
cn_msg->len = len;
memcpy(cn_msg->data, msg, len);
ret = cn_netlink_send(cn_msg, 0, 0, GFP_ATOMIC);
kfree(cn_msg);
return ret;
}
/* HVUTIL_TRANSPORT_CHARDEV */
mutex_lock(&hvt->outmsg_lock);
if (hvt->outmsg) {
/* Previous message wasn't received */
ret = -EFAULT;
goto out_unlock;
}
hvt->outmsg = kzalloc(len, GFP_KERNEL);
if (hvt->outmsg) {
memcpy(hvt->outmsg, msg, len);
hvt->outmsg_len = len;
wake_up_interruptible(&hvt->outmsg_q);
} else
ret = -ENOMEM;
out_unlock:
mutex_unlock(&hvt->outmsg_lock);
return ret;
}
struct hvutil_transport *hvutil_transport_init(const char *name,
u32 cn_idx, u32 cn_val,
int (*on_msg)(void *, int),
void (*on_reset)(void))
{
struct hvutil_transport *hvt;
hvt = kzalloc(sizeof(*hvt), GFP_KERNEL);
if (!hvt)
return NULL;
hvt->cn_id.idx = cn_idx;
hvt->cn_id.val = cn_val;
hvt->mdev.minor = MISC_DYNAMIC_MINOR;
hvt->mdev.name = name;
hvt->fops.owner = THIS_MODULE;
hvt->fops.read = hvt_op_read;
hvt->fops.write = hvt_op_write;
hvt->fops.poll = hvt_op_poll;
hvt->fops.open = hvt_op_open;
hvt->fops.release = hvt_op_release;
hvt->mdev.fops = &hvt->fops;
init_waitqueue_head(&hvt->outmsg_q);
mutex_init(&hvt->outmsg_lock);
spin_lock(&hvt_list_lock);
list_add(&hvt->list, &hvt_list);
spin_unlock(&hvt_list_lock);
hvt->on_msg = on_msg;
hvt->on_reset = on_reset;
if (misc_register(&hvt->mdev))
goto err_free_hvt;
/* Use cn_id.idx/cn_id.val to determine if we need to setup netlink */
if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0 &&
cn_add_callback(&hvt->cn_id, name, hvt_cn_callback))
goto err_free_hvt;
return hvt;
err_free_hvt:
kfree(hvt);
return NULL;
}
void hvutil_transport_destroy(struct hvutil_transport *hvt)
{
spin_lock(&hvt_list_lock);
list_del(&hvt->list);
spin_unlock(&hvt_list_lock);
if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0)
cn_del_callback(&hvt->cn_id);
misc_deregister(&hvt->mdev);
kfree(hvt->outmsg);
kfree(hvt);
}
|
