diff options
| -rw-r--r-- | Documentation/connector/cn_test.c | 194 | ||||
| -rw-r--r-- | Documentation/connector/connector.txt | 133 | ||||
| -rw-r--r-- | drivers/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/Makefile | 2 | ||||
| -rw-r--r-- | drivers/connector/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/connector/Makefile | 3 | ||||
| -rw-r--r-- | drivers/connector/cn_queue.c | 173 | ||||
| -rw-r--r-- | drivers/connector/connector.c | 486 | ||||
| -rw-r--r-- | include/linux/connector.h | 158 | ||||
| -rw-r--r-- | include/linux/netlink.h | 1 |
10 files changed, 1165 insertions, 0 deletions
diff --git a/Documentation/connector/cn_test.c b/Documentation/connector/cn_test.c new file mode 100644 index 0000000..b7de82e --- /dev/null +++ b/Documentation/connector/cn_test.c @@ -0,0 +1,194 @@ +/* + * cn_test.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/moduleparam.h> +#include <linux/skbuff.h> +#include <linux/timer.h> + +#include "connector.h" + +static struct cb_id cn_test_id = { 0x123, 0x456 }; +static char cn_test_name[] = "cn_test"; +static struct sock *nls; +static struct timer_list cn_test_timer; + +void cn_test_callback(void *data) +{ + struct cn_msg *msg = (struct cn_msg *)data; + + printk("%s: %lu: idx=%x, val=%x, seq=%u, ack=%u, len=%d: %s.\n", + __func__, jiffies, msg->id.idx, msg->id.val, + msg->seq, msg->ack, msg->len, (char *)msg->data); +} + +static int cn_test_want_notify(void) +{ + struct cn_ctl_msg *ctl; + struct cn_notify_req *req; + struct cn_msg *msg = NULL; + int size, size0; + struct sk_buff *skb; + struct nlmsghdr *nlh; + u32 group = 1; + + size0 = sizeof(*msg) + sizeof(*ctl) + 3 * sizeof(*req); + + size = NLMSG_SPACE(size0); + + skb = alloc_skb(size, GFP_ATOMIC); + if (!skb) { + printk(KERN_ERR "Failed to allocate new skb with size=%u.\n", + size); + + return -ENOMEM; + } + + nlh = NLMSG_PUT(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh)); + + msg = (struct cn_msg *)NLMSG_DATA(nlh); + + memset(msg, 0, size0); + + msg->id.idx = -1; + msg->id.val = -1; + msg->seq = 0x123; + msg->ack = 0x345; + msg->len = size0 - sizeof(*msg); + + ctl = (struct cn_ctl_msg *)(msg + 1); + + ctl->idx_notify_num = 1; + ctl->val_notify_num = 2; + ctl->group = group; + ctl->len = msg->len - sizeof(*ctl); + + req = (struct cn_notify_req *)(ctl + 1); + + /* + * Idx. + */ + req->first = cn_test_id.idx; + req->range = 10; + + /* + * Val 0. + */ + req++; + req->first = cn_test_id.val; + req->range = 10; + + /* + * Val 1. + */ + req++; + req->first = cn_test_id.val + 20; + req->range = 10; + + NETLINK_CB(skb).dst_groups = ctl->group; + //netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC); + netlink_unicast(nls, skb, 0, 0); + + printk(KERN_INFO "Request was sent. Group=0x%x.\n", ctl->group); + + return 0; + +nlmsg_failure: + printk(KERN_ERR "Failed to send %u.%u\n", msg->seq, msg->ack); + kfree_skb(skb); + return -EINVAL; +} + +static u32 cn_test_timer_counter; +static void cn_test_timer_func(unsigned long __data) +{ + struct cn_msg *m; + char data[32]; + + m = kmalloc(sizeof(*m) + sizeof(data), GFP_ATOMIC); + if (m) { + memset(m, 0, sizeof(*m) + sizeof(data)); + + memcpy(&m->id, &cn_test_id, sizeof(m->id)); + m->seq = cn_test_timer_counter; + m->len = sizeof(data); + + m->len = + scnprintf(data, sizeof(data), "counter = %u", + cn_test_timer_counter) + 1; + + memcpy(m + 1, data, m->len); + + cn_netlink_send(m, 0, gfp_any()); + kfree(m); + } + + cn_test_timer_counter++; + + mod_timer(&cn_test_timer, jiffies + HZ); +} + +static int cn_test_init(void) +{ + int err; + + err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback); + if (err) + goto err_out; + cn_test_id.val++; + err = cn_add_callback(&cn_test_id, cn_test_name, cn_test_callback); + if (err) { + cn_del_callback(&cn_test_id); + goto err_out; + } + + init_timer(&cn_test_timer); + cn_test_timer.function = cn_test_timer_func; + cn_test_timer.expires = jiffies + HZ; + cn_test_timer.data = 0; + add_timer(&cn_test_timer); + + return 0; + + err_out: + if (nls && nls->sk_socket) + sock_release(nls->sk_socket); + + return err; +} + +static void cn_test_fini(void) +{ + del_timer_sync(&cn_test_timer); + cn_del_callback(&cn_test_id); + cn_test_id.val--; + cn_del_callback(&cn_test_id); + if (nls && nls->sk_socket) + sock_release(nls->sk_socket); +} + +module_init(cn_test_init); +module_exit(cn_test_fini); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>"); +MODULE_DESCRIPTION("Connector's test module"); diff --git a/Documentation/connector/connector.txt b/Documentation/connector/connector.txt new file mode 100644 index 0000000..54a0a14b --- /dev/null +++ b/Documentation/connector/connector.txt @@ -0,0 +1,133 @@ +/*****************************************/ +Kernel Connector. +/*****************************************/ + +Kernel connector - new netlink based userspace <-> kernel space easy +to use communication module. + +Connector driver adds possibility to connect various agents using +netlink based network. One must register callback and +identifier. When driver receives special netlink message with +appropriate identifier, appropriate callback will be called. + +From the userspace point of view it's quite straightforward: + + socket(); + bind(); + send(); + recv(); + +But if kernelspace want to use full power of such connections, driver +writer must create special sockets, must know about struct sk_buff +handling... Connector allows any kernelspace agents to use netlink +based networking for inter-process communication in a significantly +easier way: + +int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *)); +void cn_netlink_send(struct cn_msg *msg, u32 __group, int gfp_mask); + +struct cb_id +{ + __u32 idx; + __u32 val; +}; + +idx and val are unique identifiers which must be registered in +connector.h for in-kernel usage. void (*callback) (void *) - is a +callback function which will be called when message with above idx.val +will be received by connector core. Argument for that function must +be dereferenced to struct cn_msg *. + +struct cn_msg +{ + struct cb_id id; + + __u32 seq; + __u32 ack; + + __u32 len; /* Length of the following data */ + __u8 data[0]; +}; + +/*****************************************/ +Connector interfaces. +/*****************************************/ + +int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *)); + +Registers new callback with connector core. + +struct cb_id *id - unique connector's user identifier. + It must be registered in connector.h for legal in-kernel users. +char *name - connector's callback symbolic name. +void (*callback) (void *) - connector's callback. + Argument must be dereferenced to struct cn_msg *. + +void cn_del_callback(struct cb_id *id); + +Unregisters new callback with connector core. + +struct cb_id *id - unique connector's user identifier. + +void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask); + +Sends message to the specified groups. It can be safely called from +any context, but may silently fail under strong memory pressure. + +struct cn_msg * - message header(with attached data). +u32 __group - destination group. + If __group is zero, then appropriate group will + be searched through all registered connector users, + and message will be delivered to the group which was + created for user with the same ID as in msg. + If __group is not zero, then message will be delivered + to the specified group. +int gfp_mask - GFP mask. + +Note: When registering new callback user, connector core assigns +netlink group to the user which is equal to it's id.idx. + +/*****************************************/ +Protocol description. +/*****************************************/ + +Current offers transport layer with fixed header. Recommended +protocol which uses such header is following: + +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 sequence number in received +message MUST be the same as in original message, and acknowledge +number MUST be the same + 1. + +If we receive message and it's sequence number is not equal to one we +are expecting, then it is new message. If we receive message and it's +sequence number is the same as one we are expecting, but it's +acknowledge is not equal acknowledge number in original message + 1, +then it is new message. + +Obviously, protocol header contains above id. + +connector allows event notification in the following form: kernel +driver or userspace process can ask connector to notify it when +selected id's will be turned on or off(registered or unregistered it's +callback). It is done by sending special command to connector +driver(it also registers itself with id={-1, -1}). + +As example of usage Documentation/connector now contains cn_test.c - +testing module which uses connector to request notification and to +send messages. + +/*****************************************/ +Reliability. +/*****************************************/ + +Netlink itself is not reliable protocol, that means that messages can +be lost due to memory pressure or process' receiving queue overflowed, +so caller is warned must be prepared. That is why struct cn_msg [main +connector's message header] contains u32 seq and u32 ack fields. diff --git a/drivers/Kconfig b/drivers/Kconfig index 46d655f..48f446d 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -4,6 +4,8 @@ menu "Device Drivers" source "drivers/base/Kconfig" +source "drivers/connector/Kconfig" + source "drivers/mtd/Kconfig" source "drivers/parport/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 86c8654..1a109a6 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -17,6 +17,8 @@ obj-$(CONFIG_PNP) += pnp/ # default. obj-y += char/ +obj-$(CONFIG_CONNECTOR) += connector/ + # i810fb and intelfb depend on char/agp/ obj-$(CONFIG_FB_I810) += video/i810/ obj-$(CONFIG_FB_INTEL) += video/intelfb/ diff --git a/drivers/connector/Kconfig b/drivers/connector/Kconfig new file mode 100644 index 0000000..0bc2059 --- /dev/null +++ b/drivers/connector/Kconfig @@ -0,0 +1,13 @@ +menu "Connector - unified userspace <-> kernelspace linker" + +config CONNECTOR + tristate "Connector - unified userspace <-> kernelspace linker" + depends on NET + ---help--- + This is unified userspace <-> kernelspace connector working on top + of the netlink socket protocol. + + Connector support can also be built as a module. If so, the module + will be called cn.ko. + +endmenu diff --git a/drivers/connector/Makefile b/drivers/connector/Makefile new file mode 100644 index 0000000..12ca79e --- /dev/null +++ b/drivers/connector/Makefile @@ -0,0 +1,3 @@ +obj-$(CONFIG_CONNECTOR) += cn.o + +cn-y += cn_queue.o connector.o diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c new file mode 100644 index 0000000..96663218 --- /dev/null +++ b/drivers/connector/cn_queue.c @@ -0,0 +1,173 @@ +/* + * cn_queue.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/workqueue.h> +#include <linux/spinlock.h> +#include <linux/slab.h> +#include <linux/skbuff.h> +#include <linux/suspend.h> +#include <linux/connector.h> +#include <linux/delay.h> + +static void cn_queue_wrapper(void *data) +{ + struct cn_callback_entry *cbq = data; + + cbq->cb->callback(cbq->cb->priv); + cbq->destruct_data(cbq->ddata); + cbq->ddata = NULL; +} + +static struct cn_callback_entry *cn_queue_alloc_callback_entry(struct cn_callback *cb) +{ + struct cn_callback_entry *cbq; + + cbq = kzalloc(sizeof(*cbq), GFP_KERNEL); + if (!cbq) { + printk(KERN_ERR "Failed to create new callback queue.\n"); + return NULL; + } + + cbq->cb = cb; + INIT_WORK(&cbq->work, &cn_queue_wrapper, cbq); + return cbq; +} + +static void cn_queue_free_callback(struct cn_callback_entry *cbq) +{ + cancel_delayed_work(&cbq->work); + flush_workqueue(cbq->pdev->cn_queue); + + kfree(cbq); +} + +int cn_cb_equal(struct cb_id *i1, struct cb_id *i2) +{ + return ((i1->idx == i2->idx) && (i1->val == i2->val)); +} + +int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb) +{ + struct cn_callback_entry *cbq, *__cbq; + int found = 0; + + cbq = cn_queue_alloc_callback_entry(cb); + if (!cbq) + return -ENOMEM; + + atomic_inc(&dev->refcnt); + cbq->pdev = dev; + + spin_lock_bh(&dev->queue_lock); + list_for_each_entry(__cbq, &dev->queue_list, callback_entry) { + if (cn_cb_equal(&__cbq->cb->id, &cb->id)) { + found = 1; + break; + } + } + if (!found) + list_add_tail(&cbq->callback_entry, &dev->queue_list); + spin_unlock_bh(&dev->queue_lock); + + if (found) { + atomic_dec(&dev->refcnt); + cn_queue_free_callback(cbq); + return -EINVAL; + } + + cbq->nls = dev->nls; + cbq->seq = 0; + cbq->group = cbq->cb->id.idx; + + return 0; +} + +void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id) +{ + struct cn_callback_entry *cbq, *n; + int found = 0; + + spin_lock_bh(&dev->queue_lock); + list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) { + if (cn_cb_equal(&cbq->cb->id, id)) { + list_del(&cbq->callback_entry); + found = 1; + break; + } + } + spin_unlock_bh(&dev->queue_lock); + + if (found) { + cn_queue_free_callback(cbq); + atomic_dec_and_test(&dev->refcnt); + } +} + +struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls) +{ + struct cn_queue_dev *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return NULL; + + snprintf(dev->name, sizeof(dev->name), "%s", name); + atomic_set(&dev->refcnt, 0); + INIT_LIST_HEAD(&dev->queue_list); + spin_lock_init(&dev->queue_lock); + + dev->nls = nls; + dev->netlink_groups = 0; + + dev->cn_queue = create_workqueue(dev->name); + if (!dev->cn_queue) { + kfree(dev); + return NULL; + } + + return dev; +} + +void cn_queue_free_dev(struct cn_queue_dev *dev) +{ + struct cn_callback_entry *cbq, *n; + + flush_workqueue(dev->cn_queue); + destroy_workqueue(dev->cn_queue); + + spin_lock_bh(&dev->queue_lock); + list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) + list_del(&cbq->callback_entry); + spin_unlock_bh(&dev->queue_lock); + + while (atomic_read(&dev->refcnt)) { + printk(KERN_INFO "Waiting for %s to become free: refcnt=%d.\n", + dev->name, atomic_read(&dev->refcnt)); + msleep(1000); + } + + kfree(dev); + dev = NULL; +} diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c new file mode 100644 index 0000000..aaf6d46 --- /dev/null +++ b/drivers/connector/connector.c @@ -0,0 +1,486 @@ +/* + * 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); diff --git a/include/linux/connector.h b/include/linux/connector.h new file mode 100644 index 0000000..96de263 --- /dev/null +++ b/include/linux/connector.h @@ -0,0 +1,158 @@ +/* + * connector.h + * + * 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 + */ + +#ifndef __CONNECTOR_H +#define __CONNECTOR_H + +#include <asm/types.h> + +#define CN_IDX_CONNECTOR 0xffffffff +#define CN_VAL_CONNECTOR 0xffffffff + +#define CN_NETLINK_USERS 1 + +/* + * Maximum connector's message size. + */ +#define CONNECTOR_MAX_MSG_SIZE 1024 + +/* + * idx and val are unique identifiers which + * are used for message routing and + * must be registered in connector.h for in-kernel usage. + */ + +struct cb_id { + __u32 idx; + __u32 val; +}; + +struct cn_msg { + struct cb_id id; + + __u32 seq; + __u32 ack; + + __u16 len; /* Length of the following data */ + __u16 flags; + __u8 data[0]; +}; + +/* + * Notify structure - requests notification about + * registering/unregistering idx/val in range [first, first+range]. + */ +struct cn_notify_req { + __u32 first; + __u32 range; +}; + +/* + * Main notification control message + * *_notify_num - number of appropriate cn_notify_req structures after + * this struct. + * group - notification receiver's idx. + * len - total length of the attached data. + */ +struct cn_ctl_msg { + __u32 idx_notify_num; + __u32 val_notify_num; + __u32 group; + __u32 len; + __u8 data[0]; +}; + +#ifdef __KERNEL__ + +#include <asm/atomic.h> + +#include <linux/list.h> +#include <linux/workqueue.h> + +#include <net/sock.h> + +#define CN_CBQ_NAMELEN 32 + +struct cn_queue_dev { + atomic_t refcnt; + unsigned char name[CN_CBQ_NAMELEN]; + + struct workqueue_struct *cn_queue; + + struct list_head queue_list; + spinlock_t queue_lock; + + int netlink_groups; + struct sock *nls; +}; + +struct cn_callback { + unsigned char name[CN_CBQ_NAMELEN]; + + struct cb_id id; + void (*callback) (void *); + void *priv; +}; + +struct cn_callback_entry { + struct list_head callback_entry; + struct cn_callback *cb; + struct work_struct work; + struct cn_queue_dev *pdev; + + void (*destruct_data) (void *); + void *ddata; + + int seq, group; + struct sock *nls; +}; + +struct cn_ctl_entry { + struct list_head notify_entry; + struct cn_ctl_msg *msg; +}; + +struct cn_dev { + struct cb_id id; + + u32 seq, groups; + struct sock *nls; + void (*input) (struct sock * sk, int len); + + struct cn_queue_dev *cbdev; +}; + +int cn_add_callback(struct cb_id *, char *, void (*callback) (void *)); +void cn_del_callback(struct cb_id *); +int cn_netlink_send(struct cn_msg *, u32, int); + +int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb); +void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id); + +struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *); +void cn_queue_free_dev(struct cn_queue_dev *dev); + +int cn_cb_equal(struct cb_id *, struct cb_id *); + +extern int cn_already_initialized; + +#endif /* __KERNEL__ */ +#endif /* __CONNECTOR_H */ diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 1675186..7bbd259 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -15,6 +15,7 @@ #define NETLINK_ISCSI 8 /* Open-iSCSI */ #define NETLINK_AUDIT 9 /* auditing */ #define NETLINK_FIB_LOOKUP 10 +#define NETLINK_CONNECTOR 11 #define NETLINK_NETFILTER 12 /* netfilter subsystem */ #define NETLINK_IP6_FW 13 #define NETLINK_DNRTMSG 14 /* DECnet routing messages */ |
