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|
/*
* 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 <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.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 DEFINE_MUTEX(notify_lock);
static LIST_HEAD(notify_list);
static struct cn_dev cdev;
static int cn_already_initialized;
/*
* 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, gfp_t 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->id.id, &msg->id)) {
found = 1;
group = __cbq->group;
break;
}
}
spin_unlock_bh(&dev->cbdev->queue_lock);
if (!found)
return -ENODEV;
} else {
group = __group;
}
if (!netlink_has_listeners(dev->nls, group))
return -ESRCH;
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;
return netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
nlmsg_failure:
kfree_skb(skb);
return -EINVAL;
}
EXPORT_SYMBOL_GPL(cn_netlink_send);
/*
* 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, *__new_cbq;
struct cn_dev *dev = &cdev;
int err = -ENODEV;
spin_lock_bh(&dev->cbdev->queue_lock);
list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
if (cn_cb_equal(&__cbq->id.id, &msg->id)) {
if (likely(!work_pending(&__cbq->work) &&
__cbq->data.ddata == NULL)) {
__cbq->data.callback_priv = msg;
__cbq->data.ddata = data;
__cbq->data.destruct_data = destruct_data;
if (queue_work(dev->cbdev->cn_queue,
&__cbq->work))
err = 0;
else
err = -EINVAL;
} else {
struct cn_callback_data *d;
err = -ENOMEM;
__new_cbq = kzalloc(sizeof(struct cn_callback_entry), GFP_ATOMIC);
if (__new_cbq) {
d = &__new_cbq->data;
d->callback_priv = msg;
d->callback = __cbq->data.callback;
d->ddata = data;
d->destruct_data = destruct_data;
d->free = __new_cbq;
INIT_WORK(&__new_cbq->work,
&cn_queue_wrapper);
if (queue_work(dev->cbdev->cn_queue,
&__new_cbq->work))
err = 0;
else {
kfree(__new_cbq);
err = -EINVAL;
}
}
}
break;
}
}
spin_unlock_bh(&dev->cbdev->queue_lock);
return err;
}
/*
* Main netlink receiving function.
*
* It checks skb, netlink header and msg sizes, and calls callback helper.
*/
static void cn_rx_skb(struct sk_buff *__skb)
{
struct cn_msg *msg;
struct nlmsghdr *nlh;
int err;
struct sk_buff *skb;
skb = skb_get(__skb);
if (skb->len >= NLMSG_SPACE(0)) {
nlh = nlmsg_hdr(skb);
if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
skb->len < nlh->nlmsg_len ||
nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
kfree_skb(skb);
return;
}
msg = NLMSG_DATA(nlh);
err = cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
if (err < 0)
kfree_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;
mutex_lock(¬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
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