forked from Minki/linux
487 lines
11 KiB
C
487 lines
11 KiB
C
|
/*
|
||
|
* connector.c
|
||
|
*
|
||
|
* 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
|
||
|
* All rights reserved.
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or modify
|
||
|
* it under the terms of the GNU General Public License as published by
|
||
|
* the Free Software Foundation; either version 2 of the License, or
|
||
|
* (at your option) any later version.
|
||
|
*
|
||
|
* 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. See the
|
||
|
* GNU General Public License for more details.
|
||
|
*
|
||
|
* You should have received a copy of the GNU General Public License
|
||
|
* along with this program; if not, write to the Free Software
|
||
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
||
|
*/
|
||
|
|
||
|
#include <linux/kernel.h>
|
||
|
#include <linux/module.h>
|
||
|
#include <linux/list.h>
|
||
|
#include <linux/skbuff.h>
|
||
|
#include <linux/netlink.h>
|
||
|
#include <linux/moduleparam.h>
|
||
|
#include <linux/connector.h>
|
||
|
|
||
|
#include <net/sock.h>
|
||
|
|
||
|
MODULE_LICENSE("GPL");
|
||
|
MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
|
||
|
MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
|
||
|
|
||
|
static u32 cn_idx = CN_IDX_CONNECTOR;
|
||
|
static u32 cn_val = CN_VAL_CONNECTOR;
|
||
|
|
||
|
module_param(cn_idx, uint, 0);
|
||
|
module_param(cn_val, uint, 0);
|
||
|
MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
|
||
|
MODULE_PARM_DESC(cn_val, "Connector's main device val.");
|
||
|
|
||
|
static DECLARE_MUTEX(notify_lock);
|
||
|
static LIST_HEAD(notify_list);
|
||
|
|
||
|
static struct cn_dev cdev;
|
||
|
|
||
|
int cn_already_initialized = 0;
|
||
|
|
||
|
/*
|
||
|
* msg->seq and msg->ack are used to determine message genealogy.
|
||
|
* When someone sends message it puts there locally unique sequence
|
||
|
* and random acknowledge numbers. Sequence number may be copied into
|
||
|
* nlmsghdr->nlmsg_seq too.
|
||
|
*
|
||
|
* Sequence number is incremented with each message to be sent.
|
||
|
*
|
||
|
* If we expect reply to our message then the sequence number in
|
||
|
* received message MUST be the same as in original message, and
|
||
|
* acknowledge number MUST be the same + 1.
|
||
|
*
|
||
|
* If we receive a message and its sequence number is not equal to the
|
||
|
* one we are expecting then it is a new message.
|
||
|
*
|
||
|
* If we receive a message and its sequence number is the same as one
|
||
|
* we are expecting but it's acknowledgement number is not equal to
|
||
|
* the acknowledgement number in the original message + 1, then it is
|
||
|
* a new message.
|
||
|
*
|
||
|
*/
|
||
|
int cn_netlink_send(struct cn_msg *msg, u32 __group, int gfp_mask)
|
||
|
{
|
||
|
struct cn_callback_entry *__cbq;
|
||
|
unsigned int size;
|
||
|
struct sk_buff *skb;
|
||
|
struct nlmsghdr *nlh;
|
||
|
struct cn_msg *data;
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
u32 group = 0;
|
||
|
int found = 0;
|
||
|
|
||
|
if (!__group) {
|
||
|
spin_lock_bh(&dev->cbdev->queue_lock);
|
||
|
list_for_each_entry(__cbq, &dev->cbdev->queue_list,
|
||
|
callback_entry) {
|
||
|
if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
|
||
|
found = 1;
|
||
|
group = __cbq->group;
|
||
|
}
|
||
|
}
|
||
|
spin_unlock_bh(&dev->cbdev->queue_lock);
|
||
|
|
||
|
if (!found)
|
||
|
return -ENODEV;
|
||
|
} else {
|
||
|
group = __group;
|
||
|
}
|
||
|
|
||
|
size = NLMSG_SPACE(sizeof(*msg) + msg->len);
|
||
|
|
||
|
skb = alloc_skb(size, gfp_mask);
|
||
|
if (!skb)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
|
||
|
|
||
|
data = NLMSG_DATA(nlh);
|
||
|
|
||
|
memcpy(data, msg, sizeof(*data) + msg->len);
|
||
|
|
||
|
NETLINK_CB(skb).dst_group = group;
|
||
|
|
||
|
netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
|
||
|
|
||
|
return 0;
|
||
|
|
||
|
nlmsg_failure:
|
||
|
kfree_skb(skb);
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Callback helper - queues work and setup destructor for given data.
|
||
|
*/
|
||
|
static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
|
||
|
{
|
||
|
struct cn_callback_entry *__cbq;
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
int found = 0;
|
||
|
|
||
|
spin_lock_bh(&dev->cbdev->queue_lock);
|
||
|
list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
|
||
|
if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
|
||
|
/*
|
||
|
* Let's scream if there is some magic and the
|
||
|
* data will arrive asynchronously here.
|
||
|
* [i.e. netlink messages will be queued].
|
||
|
* After the first warning I will fix it
|
||
|
* quickly, but now I think it is
|
||
|
* impossible. --zbr (2004_04_27).
|
||
|
*/
|
||
|
if (likely(!test_bit(0, &__cbq->work.pending) &&
|
||
|
__cbq->ddata == NULL)) {
|
||
|
__cbq->cb->priv = msg;
|
||
|
|
||
|
__cbq->ddata = data;
|
||
|
__cbq->destruct_data = destruct_data;
|
||
|
|
||
|
if (queue_work(dev->cbdev->cn_queue,
|
||
|
&__cbq->work))
|
||
|
found = 1;
|
||
|
} else {
|
||
|
printk("%s: cbq->data=%p, "
|
||
|
"work->pending=%08lx.\n",
|
||
|
__func__, __cbq->ddata,
|
||
|
__cbq->work.pending);
|
||
|
WARN_ON(1);
|
||
|
}
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
spin_unlock_bh(&dev->cbdev->queue_lock);
|
||
|
|
||
|
return found ? 0 : -ENODEV;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Skb receive helper - checks skb and msg size and calls callback
|
||
|
* helper.
|
||
|
*/
|
||
|
static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
|
||
|
{
|
||
|
u32 pid, uid, seq, group;
|
||
|
struct cn_msg *msg;
|
||
|
|
||
|
pid = NETLINK_CREDS(skb)->pid;
|
||
|
uid = NETLINK_CREDS(skb)->uid;
|
||
|
seq = nlh->nlmsg_seq;
|
||
|
group = NETLINK_CB((skb)).dst_group;
|
||
|
msg = NLMSG_DATA(nlh);
|
||
|
|
||
|
return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Main netlink receiving function.
|
||
|
*
|
||
|
* It checks skb and netlink header sizes and calls the skb receive
|
||
|
* helper with a shared skb.
|
||
|
*/
|
||
|
static void cn_rx_skb(struct sk_buff *__skb)
|
||
|
{
|
||
|
struct nlmsghdr *nlh;
|
||
|
u32 len;
|
||
|
int err;
|
||
|
struct sk_buff *skb;
|
||
|
|
||
|
skb = skb_get(__skb);
|
||
|
|
||
|
if (skb->len >= NLMSG_SPACE(0)) {
|
||
|
nlh = (struct nlmsghdr *)skb->data;
|
||
|
|
||
|
if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
|
||
|
skb->len < nlh->nlmsg_len ||
|
||
|
nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
|
||
|
kfree_skb(skb);
|
||
|
goto out;
|
||
|
}
|
||
|
|
||
|
len = NLMSG_ALIGN(nlh->nlmsg_len);
|
||
|
if (len > skb->len)
|
||
|
len = skb->len;
|
||
|
|
||
|
err = __cn_rx_skb(skb, nlh);
|
||
|
if (err < 0)
|
||
|
kfree_skb(skb);
|
||
|
}
|
||
|
|
||
|
out:
|
||
|
kfree_skb(__skb);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Netlink socket input callback - dequeues the skbs and calls the
|
||
|
* main netlink receiving function.
|
||
|
*/
|
||
|
static void cn_input(struct sock *sk, int len)
|
||
|
{
|
||
|
struct sk_buff *skb;
|
||
|
|
||
|
while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
|
||
|
cn_rx_skb(skb);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Notification routing.
|
||
|
*
|
||
|
* Gets id and checks if there are notification request for it's idx
|
||
|
* and val. If there are such requests notify the listeners with the
|
||
|
* given notify event.
|
||
|
*
|
||
|
*/
|
||
|
static void cn_notify(struct cb_id *id, u32 notify_event)
|
||
|
{
|
||
|
struct cn_ctl_entry *ent;
|
||
|
|
||
|
down(¬ify_lock);
|
||
|
list_for_each_entry(ent, ¬ify_list, notify_entry) {
|
||
|
int i;
|
||
|
struct cn_notify_req *req;
|
||
|
struct cn_ctl_msg *ctl = ent->msg;
|
||
|
int idx_found, val_found;
|
||
|
|
||
|
idx_found = val_found = 0;
|
||
|
|
||
|
req = (struct cn_notify_req *)ctl->data;
|
||
|
for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
|
||
|
if (id->idx >= req->first &&
|
||
|
id->idx < req->first + req->range) {
|
||
|
idx_found = 1;
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
|
||
|
if (id->val >= req->first &&
|
||
|
id->val < req->first + req->range) {
|
||
|
val_found = 1;
|
||
|
break;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if (idx_found && val_found) {
|
||
|
struct cn_msg m = { .ack = notify_event, };
|
||
|
|
||
|
memcpy(&m.id, id, sizeof(m.id));
|
||
|
cn_netlink_send(&m, ctl->group, GFP_KERNEL);
|
||
|
}
|
||
|
}
|
||
|
up(¬ify_lock);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Callback add routing - adds callback with given ID and name.
|
||
|
* If there is registered callback with the same ID it will not be added.
|
||
|
*
|
||
|
* May sleep.
|
||
|
*/
|
||
|
int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
|
||
|
{
|
||
|
int err;
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
struct cn_callback *cb;
|
||
|
|
||
|
cb = kzalloc(sizeof(*cb), GFP_KERNEL);
|
||
|
if (!cb)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
scnprintf(cb->name, sizeof(cb->name), "%s", name);
|
||
|
|
||
|
memcpy(&cb->id, id, sizeof(cb->id));
|
||
|
cb->callback = callback;
|
||
|
|
||
|
err = cn_queue_add_callback(dev->cbdev, cb);
|
||
|
if (err) {
|
||
|
kfree(cb);
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
cn_notify(id, 0);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Callback remove routing - removes callback
|
||
|
* with given ID.
|
||
|
* If there is no registered callback with given
|
||
|
* ID nothing happens.
|
||
|
*
|
||
|
* May sleep while waiting for reference counter to become zero.
|
||
|
*/
|
||
|
void cn_del_callback(struct cb_id *id)
|
||
|
{
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
|
||
|
cn_queue_del_callback(dev->cbdev, id);
|
||
|
cn_notify(id, 1);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Checks two connector's control messages to be the same.
|
||
|
* Returns 1 if they are the same or if the first one is corrupted.
|
||
|
*/
|
||
|
static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
|
||
|
{
|
||
|
int i;
|
||
|
struct cn_notify_req *req1, *req2;
|
||
|
|
||
|
if (m1->idx_notify_num != m2->idx_notify_num)
|
||
|
return 0;
|
||
|
|
||
|
if (m1->val_notify_num != m2->val_notify_num)
|
||
|
return 0;
|
||
|
|
||
|
if (m1->len != m2->len)
|
||
|
return 0;
|
||
|
|
||
|
if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
|
||
|
m1->len)
|
||
|
return 1;
|
||
|
|
||
|
req1 = (struct cn_notify_req *)m1->data;
|
||
|
req2 = (struct cn_notify_req *)m2->data;
|
||
|
|
||
|
for (i = 0; i < m1->idx_notify_num; ++i) {
|
||
|
if (req1->first != req2->first || req1->range != req2->range)
|
||
|
return 0;
|
||
|
req1++;
|
||
|
req2++;
|
||
|
}
|
||
|
|
||
|
for (i = 0; i < m1->val_notify_num; ++i) {
|
||
|
if (req1->first != req2->first || req1->range != req2->range)
|
||
|
return 0;
|
||
|
req1++;
|
||
|
req2++;
|
||
|
}
|
||
|
|
||
|
return 1;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Main connector device's callback.
|
||
|
*
|
||
|
* Used for notification of a request's processing.
|
||
|
*/
|
||
|
static void cn_callback(void *data)
|
||
|
{
|
||
|
struct cn_msg *msg = data;
|
||
|
struct cn_ctl_msg *ctl;
|
||
|
struct cn_ctl_entry *ent;
|
||
|
u32 size;
|
||
|
|
||
|
if (msg->len < sizeof(*ctl))
|
||
|
return;
|
||
|
|
||
|
ctl = (struct cn_ctl_msg *)msg->data;
|
||
|
|
||
|
size = (sizeof(*ctl) + ((ctl->idx_notify_num +
|
||
|
ctl->val_notify_num) *
|
||
|
sizeof(struct cn_notify_req)));
|
||
|
|
||
|
if (msg->len != size)
|
||
|
return;
|
||
|
|
||
|
if (ctl->len + sizeof(*ctl) != msg->len)
|
||
|
return;
|
||
|
|
||
|
/*
|
||
|
* Remove notification.
|
||
|
*/
|
||
|
if (ctl->group == 0) {
|
||
|
struct cn_ctl_entry *n;
|
||
|
|
||
|
down(¬ify_lock);
|
||
|
list_for_each_entry_safe(ent, n, ¬ify_list, notify_entry) {
|
||
|
if (cn_ctl_msg_equals(ent->msg, ctl)) {
|
||
|
list_del(&ent->notify_entry);
|
||
|
kfree(ent);
|
||
|
}
|
||
|
}
|
||
|
up(¬ify_lock);
|
||
|
|
||
|
return;
|
||
|
}
|
||
|
|
||
|
size += sizeof(*ent);
|
||
|
|
||
|
ent = kzalloc(size, GFP_KERNEL);
|
||
|
if (!ent)
|
||
|
return;
|
||
|
|
||
|
ent->msg = (struct cn_ctl_msg *)(ent + 1);
|
||
|
|
||
|
memcpy(ent->msg, ctl, size - sizeof(*ent));
|
||
|
|
||
|
down(¬ify_lock);
|
||
|
list_add(&ent->notify_entry, ¬ify_list);
|
||
|
up(¬ify_lock);
|
||
|
}
|
||
|
|
||
|
static int __init cn_init(void)
|
||
|
{
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
int err;
|
||
|
|
||
|
dev->input = cn_input;
|
||
|
dev->id.idx = cn_idx;
|
||
|
dev->id.val = cn_val;
|
||
|
|
||
|
dev->nls = netlink_kernel_create(NETLINK_CONNECTOR,
|
||
|
CN_NETLINK_USERS + 0xf,
|
||
|
dev->input, THIS_MODULE);
|
||
|
if (!dev->nls)
|
||
|
return -EIO;
|
||
|
|
||
|
dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls);
|
||
|
if (!dev->cbdev) {
|
||
|
if (dev->nls->sk_socket)
|
||
|
sock_release(dev->nls->sk_socket);
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
err = cn_add_callback(&dev->id, "connector", &cn_callback);
|
||
|
if (err) {
|
||
|
cn_queue_free_dev(dev->cbdev);
|
||
|
if (dev->nls->sk_socket)
|
||
|
sock_release(dev->nls->sk_socket);
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
cn_already_initialized = 1;
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static void __exit cn_fini(void)
|
||
|
{
|
||
|
struct cn_dev *dev = &cdev;
|
||
|
|
||
|
cn_already_initialized = 0;
|
||
|
|
||
|
cn_del_callback(&dev->id);
|
||
|
cn_queue_free_dev(dev->cbdev);
|
||
|
if (dev->nls->sk_socket)
|
||
|
sock_release(dev->nls->sk_socket);
|
||
|
}
|
||
|
|
||
|
module_init(cn_init);
|
||
|
module_exit(cn_fini);
|
||
|
|
||
|
EXPORT_SYMBOL_GPL(cn_add_callback);
|
||
|
EXPORT_SYMBOL_GPL(cn_del_callback);
|
||
|
EXPORT_SYMBOL_GPL(cn_netlink_send);
|