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@@ -0,0 +1,486 @@
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+/*
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+ * connector.c
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+ *
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+ * 2004-2005 Copyright (c) Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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+ * All rights reserved.
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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+ */
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+
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+#include <linux/kernel.h>
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+#include <linux/module.h>
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+#include <linux/list.h>
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+#include <linux/skbuff.h>
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+#include <linux/netlink.h>
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+#include <linux/moduleparam.h>
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+#include <linux/connector.h>
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+
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+#include <net/sock.h>
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+
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+MODULE_LICENSE("GPL");
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+MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
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+MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector.");
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+
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+static u32 cn_idx = CN_IDX_CONNECTOR;
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+static u32 cn_val = CN_VAL_CONNECTOR;
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+
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+module_param(cn_idx, uint, 0);
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+module_param(cn_val, uint, 0);
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+MODULE_PARM_DESC(cn_idx, "Connector's main device idx.");
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+MODULE_PARM_DESC(cn_val, "Connector's main device val.");
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+
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+static DECLARE_MUTEX(notify_lock);
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+static LIST_HEAD(notify_list);
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+
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+static struct cn_dev cdev;
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+
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+int cn_already_initialized = 0;
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+
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+/*
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+ * msg->seq and msg->ack are used to determine message genealogy.
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+ * When someone sends message it puts there locally unique sequence
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+ * and random acknowledge numbers. Sequence number may be copied into
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+ * nlmsghdr->nlmsg_seq too.
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+ *
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+ * Sequence number is incremented with each message to be sent.
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+ *
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+ * If we expect reply to our message then the sequence number in
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+ * received message MUST be the same as in original message, and
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+ * acknowledge number MUST be the same + 1.
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+ *
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+ * If we receive a message and its sequence number is not equal to the
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+ * one we are expecting then it is a new message.
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+ *
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+ * If we receive a message and its sequence number is the same as one
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+ * we are expecting but it's acknowledgement number is not equal to
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+ * the acknowledgement number in the original message + 1, then it is
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+ * a new message.
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+ *
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+ */
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+int cn_netlink_send(struct cn_msg *msg, u32 __group, int gfp_mask)
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+{
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+ struct cn_callback_entry *__cbq;
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+ unsigned int size;
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+ struct sk_buff *skb;
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+ struct nlmsghdr *nlh;
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+ struct cn_msg *data;
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+ struct cn_dev *dev = &cdev;
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+ u32 group = 0;
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+ int found = 0;
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+
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+ if (!__group) {
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+ spin_lock_bh(&dev->cbdev->queue_lock);
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+ list_for_each_entry(__cbq, &dev->cbdev->queue_list,
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+ callback_entry) {
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+ if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
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+ found = 1;
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+ group = __cbq->group;
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+ }
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+ }
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+ spin_unlock_bh(&dev->cbdev->queue_lock);
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+
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+ if (!found)
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+ return -ENODEV;
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+ } else {
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+ group = __group;
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+ }
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+
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+ size = NLMSG_SPACE(sizeof(*msg) + msg->len);
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+
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+ skb = alloc_skb(size, gfp_mask);
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+ if (!skb)
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+ return -ENOMEM;
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+
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+ nlh = NLMSG_PUT(skb, 0, msg->seq, NLMSG_DONE, size - sizeof(*nlh));
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+
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+ data = NLMSG_DATA(nlh);
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+
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+ memcpy(data, msg, sizeof(*data) + msg->len);
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+
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+ NETLINK_CB(skb).dst_group = group;
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+
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+ netlink_broadcast(dev->nls, skb, 0, group, gfp_mask);
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+
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+ return 0;
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+
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+nlmsg_failure:
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+ kfree_skb(skb);
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+ return -EINVAL;
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+}
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+
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+/*
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+ * Callback helper - queues work and setup destructor for given data.
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+ */
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+static int cn_call_callback(struct cn_msg *msg, void (*destruct_data)(void *), void *data)
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+{
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+ struct cn_callback_entry *__cbq;
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+ struct cn_dev *dev = &cdev;
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+ int found = 0;
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+
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+ spin_lock_bh(&dev->cbdev->queue_lock);
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+ list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
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+ if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
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+ /*
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+ * Let's scream if there is some magic and the
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+ * data will arrive asynchronously here.
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+ * [i.e. netlink messages will be queued].
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+ * After the first warning I will fix it
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+ * quickly, but now I think it is
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+ * impossible. --zbr (2004_04_27).
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+ */
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+ if (likely(!test_bit(0, &__cbq->work.pending) &&
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+ __cbq->ddata == NULL)) {
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+ __cbq->cb->priv = msg;
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+
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+ __cbq->ddata = data;
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+ __cbq->destruct_data = destruct_data;
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+
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+ if (queue_work(dev->cbdev->cn_queue,
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+ &__cbq->work))
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+ found = 1;
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+ } else {
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+ printk("%s: cbq->data=%p, "
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+ "work->pending=%08lx.\n",
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+ __func__, __cbq->ddata,
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+ __cbq->work.pending);
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+ WARN_ON(1);
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+ }
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+ break;
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+ }
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+ }
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+ spin_unlock_bh(&dev->cbdev->queue_lock);
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+
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+ return found ? 0 : -ENODEV;
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+}
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+
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+/*
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+ * Skb receive helper - checks skb and msg size and calls callback
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+ * helper.
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+ */
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+static int __cn_rx_skb(struct sk_buff *skb, struct nlmsghdr *nlh)
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+{
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+ u32 pid, uid, seq, group;
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+ struct cn_msg *msg;
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+
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+ pid = NETLINK_CREDS(skb)->pid;
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+ uid = NETLINK_CREDS(skb)->uid;
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+ seq = nlh->nlmsg_seq;
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+ group = NETLINK_CB((skb)).dst_group;
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+ msg = NLMSG_DATA(nlh);
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+
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+ return cn_call_callback(msg, (void (*)(void *))kfree_skb, skb);
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+}
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+
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+/*
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+ * Main netlink receiving function.
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+ *
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+ * It checks skb and netlink header sizes and calls the skb receive
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+ * helper with a shared skb.
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+ */
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+static void cn_rx_skb(struct sk_buff *__skb)
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+{
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+ struct nlmsghdr *nlh;
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+ u32 len;
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+ int err;
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+ struct sk_buff *skb;
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+
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+ skb = skb_get(__skb);
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+
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+ if (skb->len >= NLMSG_SPACE(0)) {
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+ nlh = (struct nlmsghdr *)skb->data;
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+
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+ if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
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+ skb->len < nlh->nlmsg_len ||
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+ nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
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+ kfree_skb(skb);
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+ goto out;
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+ }
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+
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+ len = NLMSG_ALIGN(nlh->nlmsg_len);
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+ if (len > skb->len)
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+ len = skb->len;
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+
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+ err = __cn_rx_skb(skb, nlh);
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+ if (err < 0)
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+ kfree_skb(skb);
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+ }
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+
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+out:
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+ kfree_skb(__skb);
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+}
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+
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+/*
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+ * Netlink socket input callback - dequeues the skbs and calls the
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+ * main netlink receiving function.
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+ */
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+static void cn_input(struct sock *sk, int len)
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+{
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+ struct sk_buff *skb;
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+
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+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL)
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+ cn_rx_skb(skb);
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+}
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+
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+/*
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+ * Notification routing.
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+ *
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+ * Gets id and checks if there are notification request for it's idx
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+ * and val. If there are such requests notify the listeners with the
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+ * given notify event.
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+ *
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+ */
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+static void cn_notify(struct cb_id *id, u32 notify_event)
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+{
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+ struct cn_ctl_entry *ent;
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+
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+ down(¬ify_lock);
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+ list_for_each_entry(ent, ¬ify_list, notify_entry) {
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+ int i;
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+ struct cn_notify_req *req;
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+ struct cn_ctl_msg *ctl = ent->msg;
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+ int idx_found, val_found;
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+
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+ idx_found = val_found = 0;
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+
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+ req = (struct cn_notify_req *)ctl->data;
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+ for (i = 0; i < ctl->idx_notify_num; ++i, ++req) {
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+ if (id->idx >= req->first &&
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+ id->idx < req->first + req->range) {
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+ idx_found = 1;
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+ break;
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+ }
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+ }
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+
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+ for (i = 0; i < ctl->val_notify_num; ++i, ++req) {
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+ if (id->val >= req->first &&
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+ id->val < req->first + req->range) {
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+ val_found = 1;
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+ break;
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+ }
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+ }
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+
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+ if (idx_found && val_found) {
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+ struct cn_msg m = { .ack = notify_event, };
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+
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+ memcpy(&m.id, id, sizeof(m.id));
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+ cn_netlink_send(&m, ctl->group, GFP_KERNEL);
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+ }
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+ }
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+ up(¬ify_lock);
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+}
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+
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+/*
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+ * Callback add routing - adds callback with given ID and name.
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+ * If there is registered callback with the same ID it will not be added.
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+ *
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+ * May sleep.
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+ */
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+int cn_add_callback(struct cb_id *id, char *name, void (*callback)(void *))
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+{
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+ int err;
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+ struct cn_dev *dev = &cdev;
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+ struct cn_callback *cb;
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+
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+ cb = kzalloc(sizeof(*cb), GFP_KERNEL);
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+ if (!cb)
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+ return -ENOMEM;
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+
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+ scnprintf(cb->name, sizeof(cb->name), "%s", name);
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+
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+ memcpy(&cb->id, id, sizeof(cb->id));
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+ cb->callback = callback;
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+
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+ err = cn_queue_add_callback(dev->cbdev, cb);
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+ if (err) {
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+ kfree(cb);
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+ return err;
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+ }
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+
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+ cn_notify(id, 0);
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+
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+ return 0;
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+}
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+
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+/*
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+ * Callback remove routing - removes callback
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+ * with given ID.
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+ * If there is no registered callback with given
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+ * ID nothing happens.
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+ *
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+ * May sleep while waiting for reference counter to become zero.
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+ */
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+void cn_del_callback(struct cb_id *id)
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+{
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+ struct cn_dev *dev = &cdev;
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+
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+ cn_queue_del_callback(dev->cbdev, id);
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+ cn_notify(id, 1);
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+}
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+
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+/*
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+ * Checks two connector's control messages to be the same.
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+ * Returns 1 if they are the same or if the first one is corrupted.
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+ */
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+static int cn_ctl_msg_equals(struct cn_ctl_msg *m1, struct cn_ctl_msg *m2)
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+{
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+ int i;
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+ struct cn_notify_req *req1, *req2;
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+
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+ if (m1->idx_notify_num != m2->idx_notify_num)
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+ return 0;
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+
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+ if (m1->val_notify_num != m2->val_notify_num)
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+ return 0;
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+
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+ if (m1->len != m2->len)
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+ return 0;
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+
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+ if ((m1->idx_notify_num + m1->val_notify_num) * sizeof(*req1) !=
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+ m1->len)
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+ return 1;
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+
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+ req1 = (struct cn_notify_req *)m1->data;
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+ req2 = (struct cn_notify_req *)m2->data;
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+
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+ for (i = 0; i < m1->idx_notify_num; ++i) {
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+ if (req1->first != req2->first || req1->range != req2->range)
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+ return 0;
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+ req1++;
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+ req2++;
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+ }
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+
|
|
|
|
+ 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);
|