From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- drivers/connector/connector.c | 292 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 292 insertions(+) create mode 100644 drivers/connector/connector.c (limited to 'drivers/connector/connector.c') diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c new file mode 100644 index 00000000..dde6a0fa --- /dev/null +++ b/drivers/connector/connector.c @@ -0,0 +1,292 @@ +/* + * connector.c + * + * 2004+ Copyright (c) Evgeniy Polyakov + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Evgeniy Polyakov "); +MODULE_DESCRIPTION("Generic userspace <-> kernelspace connector."); +MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_CONNECTOR); + +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 sk_buff *skb) +{ + struct cn_callback_entry *i, *cbq = NULL; + struct cn_dev *dev = &cdev; + struct cn_msg *msg = NLMSG_DATA(nlmsg_hdr(skb)); + struct netlink_skb_parms *nsp = &NETLINK_CB(skb); + int err = -ENODEV; + + spin_lock_bh(&dev->cbdev->queue_lock); + list_for_each_entry(i, &dev->cbdev->queue_list, callback_entry) { + if (cn_cb_equal(&i->id.id, &msg->id)) { + atomic_inc(&i->refcnt); + cbq = i; + break; + } + } + spin_unlock_bh(&dev->cbdev->queue_lock); + + if (cbq != NULL) { + err = 0; + cbq->callback(msg, nsp); + kfree_skb(skb); + cn_queue_release_callback(cbq); + err = 0; + } + + 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 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; + } + + err = cn_call_callback(skb); + if (err < 0) + kfree_skb(skb); + } +} + +/* + * 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, const char *name, + void (*callback)(struct cn_msg *, struct netlink_skb_parms *)) +{ + int err; + struct cn_dev *dev = &cdev; + + if (!cn_already_initialized) + return -EAGAIN; + + err = cn_queue_add_callback(dev->cbdev, name, id, callback); + if (err) + return err; + + return 0; +} +EXPORT_SYMBOL_GPL(cn_add_callback); + +/* + * 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); +} +EXPORT_SYMBOL_GPL(cn_del_callback); + +static int cn_proc_show(struct seq_file *m, void *v) +{ + struct cn_queue_dev *dev = cdev.cbdev; + struct cn_callback_entry *cbq; + + seq_printf(m, "Name ID\n"); + + spin_lock_bh(&dev->queue_lock); + + list_for_each_entry(cbq, &dev->queue_list, callback_entry) { + seq_printf(m, "%-15s %u:%u\n", + cbq->id.name, + cbq->id.id.idx, + cbq->id.id.val); + } + + spin_unlock_bh(&dev->queue_lock); + + return 0; +} + +static int cn_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, cn_proc_show, NULL); +} + +static const struct file_operations cn_file_ops = { + .owner = THIS_MODULE, + .open = cn_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release +}; + +static int __devinit cn_init(void) +{ + struct cn_dev *dev = &cdev; + + dev->input = cn_rx_skb; + + dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, + CN_NETLINK_USERS + 0xf, + dev->input, NULL, THIS_MODULE); + if (!dev->nls) + return -EIO; + + dev->cbdev = cn_queue_alloc_dev("cqueue", dev->nls); + if (!dev->cbdev) { + netlink_kernel_release(dev->nls); + return -EINVAL; + } + + cn_already_initialized = 1; + + proc_net_fops_create(&init_net, "connector", S_IRUGO, &cn_file_ops); + + return 0; +} + +static void __devexit cn_fini(void) +{ + struct cn_dev *dev = &cdev; + + cn_already_initialized = 0; + + proc_net_remove(&init_net, "connector"); + + cn_queue_free_dev(dev->cbdev); + netlink_kernel_release(dev->nls); +} + +subsys_initcall(cn_init); +module_exit(cn_fini); -- cgit v1.2.3