v4.19.13 snapshot.
diff --git a/drivers/connector/Kconfig b/drivers/connector/Kconfig
new file mode 100644
index 0000000..3de5f3a
--- /dev/null
+++ b/drivers/connector/Kconfig
@@ -0,0 +1,22 @@
+
+menuconfig 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.
+
+if CONNECTOR
+
+config PROC_EVENTS
+ bool "Report process events to userspace"
+ depends on CONNECTOR=y
+ default y
+ ---help---
+ Provide a connector that reports process events to userspace. Send
+ events such as fork, exec, id change (uid, gid, suid, etc), and exit.
+
+endif # CONNECTOR
diff --git a/drivers/connector/Makefile b/drivers/connector/Makefile
new file mode 100644
index 0000000..1f255e4
--- /dev/null
+++ b/drivers/connector/Makefile
@@ -0,0 +1,4 @@
+obj-$(CONFIG_CONNECTOR) += cn.o
+obj-$(CONFIG_PROC_EVENTS) += cn_proc.o
+
+cn-y += cn_queue.o connector.o
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
new file mode 100644
index 0000000..ed5e424
--- /dev/null
+++ b/drivers/connector/cn_proc.c
@@ -0,0 +1,396 @@
+/*
+ * cn_proc.c - process events connector
+ *
+ * Copyright (C) Matt Helsley, IBM Corp. 2005
+ * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
+ * Original copyright notice follows:
+ * Copyright (C) 2005 BULL SA.
+ *
+ *
+ * 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/ktime.h>
+#include <linux/init.h>
+#include <linux/connector.h>
+#include <linux/gfp.h>
+#include <linux/ptrace.h>
+#include <linux/atomic.h>
+#include <linux/pid_namespace.h>
+
+#include <linux/cn_proc.h>
+
+/*
+ * Size of a cn_msg followed by a proc_event structure. Since the
+ * sizeof struct cn_msg is a multiple of 4 bytes, but not 8 bytes, we
+ * add one 4-byte word to the size here, and then start the actual
+ * cn_msg structure 4 bytes into the stack buffer. The result is that
+ * the immediately following proc_event structure is aligned to 8 bytes.
+ */
+#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event) + 4)
+
+/* See comment above; we test our assumption about sizeof struct cn_msg here. */
+static inline struct cn_msg *buffer_to_cn_msg(__u8 *buffer)
+{
+ BUILD_BUG_ON(sizeof(struct cn_msg) != 20);
+ return (struct cn_msg *)(buffer + 4);
+}
+
+static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
+static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
+
+/* proc_event_counts is used as the sequence number of the netlink message */
+static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
+
+static inline void send_msg(struct cn_msg *msg)
+{
+ preempt_disable();
+
+ msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
+ ((struct proc_event *)msg->data)->cpu = smp_processor_id();
+
+ /*
+ * Preemption remains disabled during send to ensure the messages are
+ * ordered according to their sequence numbers.
+ *
+ * If cn_netlink_send() fails, the data is not sent.
+ */
+ cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
+
+ preempt_enable();
+}
+
+void proc_fork_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+ struct task_struct *parent;
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_FORK;
+ rcu_read_lock();
+ parent = rcu_dereference(task->real_parent);
+ ev->event_data.fork.parent_pid = parent->pid;
+ ev->event_data.fork.parent_tgid = parent->tgid;
+ rcu_read_unlock();
+ ev->event_data.fork.child_pid = task->pid;
+ ev->event_data.fork.child_tgid = task->tgid;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_exec_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_EXEC;
+ ev->event_data.exec.process_pid = task->pid;
+ ev->event_data.exec.process_tgid = task->tgid;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_id_connector(struct task_struct *task, int which_id)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+ const struct cred *cred;
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->what = which_id;
+ ev->event_data.id.process_pid = task->pid;
+ ev->event_data.id.process_tgid = task->tgid;
+ rcu_read_lock();
+ cred = __task_cred(task);
+ if (which_id == PROC_EVENT_UID) {
+ ev->event_data.id.r.ruid = from_kuid_munged(&init_user_ns, cred->uid);
+ ev->event_data.id.e.euid = from_kuid_munged(&init_user_ns, cred->euid);
+ } else if (which_id == PROC_EVENT_GID) {
+ ev->event_data.id.r.rgid = from_kgid_munged(&init_user_ns, cred->gid);
+ ev->event_data.id.e.egid = from_kgid_munged(&init_user_ns, cred->egid);
+ } else {
+ rcu_read_unlock();
+ return;
+ }
+ rcu_read_unlock();
+ ev->timestamp_ns = ktime_get_ns();
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_sid_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_SID;
+ ev->event_data.sid.process_pid = task->pid;
+ ev->event_data.sid.process_tgid = task->tgid;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_PTRACE;
+ ev->event_data.ptrace.process_pid = task->pid;
+ ev->event_data.ptrace.process_tgid = task->tgid;
+ if (ptrace_id == PTRACE_ATTACH) {
+ ev->event_data.ptrace.tracer_pid = current->pid;
+ ev->event_data.ptrace.tracer_tgid = current->tgid;
+ } else if (ptrace_id == PTRACE_DETACH) {
+ ev->event_data.ptrace.tracer_pid = 0;
+ ev->event_data.ptrace.tracer_tgid = 0;
+ } else
+ return;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_comm_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_COMM;
+ ev->event_data.comm.process_pid = task->pid;
+ ev->event_data.comm.process_tgid = task->tgid;
+ get_task_comm(ev->event_data.comm.comm, task);
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_coredump_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_COREDUMP;
+ ev->event_data.coredump.process_pid = task->pid;
+ ev->event_data.coredump.process_tgid = task->tgid;
+ ev->event_data.coredump.parent_pid = task->real_parent->pid;
+ ev->event_data.coredump.parent_tgid = task->real_parent->tgid;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+void proc_exit_connector(struct task_struct *task)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ ev->timestamp_ns = ktime_get_ns();
+ ev->what = PROC_EVENT_EXIT;
+ ev->event_data.exit.process_pid = task->pid;
+ ev->event_data.exit.process_tgid = task->tgid;
+ ev->event_data.exit.exit_code = task->exit_code;
+ ev->event_data.exit.exit_signal = task->exit_signal;
+ ev->event_data.exit.parent_pid = task->real_parent->pid;
+ ev->event_data.exit.parent_tgid = task->real_parent->tgid;
+
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = 0; /* not used */
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+/*
+ * Send an acknowledgement message to userspace
+ *
+ * Use 0 for success, EFOO otherwise.
+ * Note: this is the negative of conventional kernel error
+ * values because it's not being returned via syscall return
+ * mechanisms.
+ */
+static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
+{
+ struct cn_msg *msg;
+ struct proc_event *ev;
+ __u8 buffer[CN_PROC_MSG_SIZE] __aligned(8);
+
+ if (atomic_read(&proc_event_num_listeners) < 1)
+ return;
+
+ msg = buffer_to_cn_msg(buffer);
+ ev = (struct proc_event *)msg->data;
+ memset(&ev->event_data, 0, sizeof(ev->event_data));
+ msg->seq = rcvd_seq;
+ ev->timestamp_ns = ktime_get_ns();
+ ev->cpu = -1;
+ ev->what = PROC_EVENT_NONE;
+ ev->event_data.ack.err = err;
+ memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+ msg->ack = rcvd_ack + 1;
+ msg->len = sizeof(*ev);
+ msg->flags = 0; /* not used */
+ send_msg(msg);
+}
+
+/**
+ * cn_proc_mcast_ctl
+ * @data: message sent from userspace via the connector
+ */
+static void cn_proc_mcast_ctl(struct cn_msg *msg,
+ struct netlink_skb_parms *nsp)
+{
+ enum proc_cn_mcast_op *mc_op = NULL;
+ int err = 0;
+
+ if (msg->len != sizeof(*mc_op))
+ return;
+
+ /*
+ * Events are reported with respect to the initial pid
+ * and user namespaces so ignore requestors from
+ * other namespaces.
+ */
+ if ((current_user_ns() != &init_user_ns) ||
+ (task_active_pid_ns(current) != &init_pid_ns))
+ return;
+
+ /* Can only change if privileged. */
+ if (!__netlink_ns_capable(nsp, &init_user_ns, CAP_NET_ADMIN)) {
+ err = EPERM;
+ goto out;
+ }
+
+ mc_op = (enum proc_cn_mcast_op *)msg->data;
+ switch (*mc_op) {
+ case PROC_CN_MCAST_LISTEN:
+ atomic_inc(&proc_event_num_listeners);
+ break;
+ case PROC_CN_MCAST_IGNORE:
+ atomic_dec(&proc_event_num_listeners);
+ break;
+ default:
+ err = EINVAL;
+ break;
+ }
+
+out:
+ cn_proc_ack(err, msg->seq, msg->ack);
+}
+
+/*
+ * cn_proc_init - initialization entry point
+ *
+ * Adds the connector callback to the connector driver.
+ */
+static int __init cn_proc_init(void)
+{
+ int err = cn_add_callback(&cn_proc_event_id,
+ "cn_proc",
+ &cn_proc_mcast_ctl);
+ if (err) {
+ pr_warn("cn_proc failed to register\n");
+ return err;
+ }
+ return 0;
+}
+device_initcall(cn_proc_init);
diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c
new file mode 100644
index 0000000..9c54fdf
--- /dev/null
+++ b/drivers/connector/cn_queue.c
@@ -0,0 +1,161 @@
+/*
+ * cn_queue.c
+ *
+ * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
+ * 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 struct cn_callback_entry *
+cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
+ struct cb_id *id,
+ void (*callback)(struct cn_msg *,
+ struct netlink_skb_parms *))
+{
+ struct cn_callback_entry *cbq;
+
+ cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
+ if (!cbq) {
+ pr_err("Failed to create new callback queue.\n");
+ return NULL;
+ }
+
+ refcount_set(&cbq->refcnt, 1);
+
+ atomic_inc(&dev->refcnt);
+ cbq->pdev = dev;
+
+ snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
+ memcpy(&cbq->id.id, id, sizeof(struct cb_id));
+ cbq->callback = callback;
+ return cbq;
+}
+
+void cn_queue_release_callback(struct cn_callback_entry *cbq)
+{
+ if (!refcount_dec_and_test(&cbq->refcnt))
+ return;
+
+ atomic_dec(&cbq->pdev->refcnt);
+ 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, const char *name,
+ struct cb_id *id,
+ void (*callback)(struct cn_msg *,
+ struct netlink_skb_parms *))
+{
+ struct cn_callback_entry *cbq, *__cbq;
+ int found = 0;
+
+ cbq = cn_queue_alloc_callback_entry(dev, name, id, callback);
+ if (!cbq)
+ return -ENOMEM;
+
+ spin_lock_bh(&dev->queue_lock);
+ list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
+ if (cn_cb_equal(&__cbq->id.id, id)) {
+ found = 1;
+ break;
+ }
+ }
+ if (!found)
+ list_add_tail(&cbq->callback_entry, &dev->queue_list);
+ spin_unlock_bh(&dev->queue_lock);
+
+ if (found) {
+ cn_queue_release_callback(cbq);
+ return -EINVAL;
+ }
+
+ cbq->seq = 0;
+ cbq->group = cbq->id.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->id.id, id)) {
+ list_del(&cbq->callback_entry);
+ found = 1;
+ break;
+ }
+ }
+ spin_unlock_bh(&dev->queue_lock);
+
+ if (found)
+ cn_queue_release_callback(cbq);
+}
+
+struct cn_queue_dev *cn_queue_alloc_dev(const 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;
+
+ return dev;
+}
+
+void cn_queue_free_dev(struct cn_queue_dev *dev)
+{
+ struct cn_callback_entry *cbq, *n;
+
+ 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)) {
+ pr_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..eeb7d31
--- /dev/null
+++ b/drivers/connector/connector.c
@@ -0,0 +1,306 @@
+/*
+ * connector.c
+ *
+ * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
+ * 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/compiler.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/skbuff.h>
+#include <net/netlink.h>
+#include <linux/moduleparam.h>
+#include <linux/connector.h>
+#include <linux/slab.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 <zbr@ioremap.net>");
+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;
+
+/*
+ * Sends mult (multiple) cn_msg at a time.
+ *
+ * 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 a 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.
+ *
+ * If msg->len != len, then additional cn_msg messages are expected following
+ * the first msg.
+ *
+ * The message is sent to, the portid if given, the group if given, both if
+ * both, or if both are zero then the group is looked up and sent there.
+ */
+int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, 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 (portid || __group) {
+ group = __group;
+ } else {
+ 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;
+ }
+
+ if (!portid && !netlink_has_listeners(dev->nls, group))
+ return -ESRCH;
+
+ size = sizeof(*msg) + len;
+
+ skb = nlmsg_new(size, gfp_mask);
+ if (!skb)
+ return -ENOMEM;
+
+ nlh = nlmsg_put(skb, 0, msg->seq, NLMSG_DONE, size, 0);
+ if (!nlh) {
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ data = nlmsg_data(nlh);
+
+ memcpy(data, msg, size);
+
+ NETLINK_CB(skb).dst_group = group;
+
+ if (group)
+ return netlink_broadcast(dev->nls, skb, portid, group,
+ gfp_mask);
+ return netlink_unicast(dev->nls, skb, portid,
+ !gfpflags_allow_blocking(gfp_mask));
+}
+EXPORT_SYMBOL_GPL(cn_netlink_send_mult);
+
+/* same as cn_netlink_send_mult except msg->len is used for len */
+int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group,
+ gfp_t gfp_mask)
+{
+ return cn_netlink_send_mult(msg, msg->len, portid, __group, gfp_mask);
+}
+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 nlmsghdr *nlh;
+ 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;
+
+ /* verify msg->len is within skb */
+ nlh = nlmsg_hdr(skb);
+ if (nlh->nlmsg_len < NLMSG_HDRLEN + sizeof(struct cn_msg) + msg->len)
+ return -EINVAL;
+
+ 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)) {
+ refcount_inc(&i->refcnt);
+ cbq = i;
+ break;
+ }
+ }
+ spin_unlock_bh(&dev->cbdev->queue_lock);
+
+ if (cbq != NULL) {
+ 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 len, err;
+
+ if (skb->len >= NLMSG_HDRLEN) {
+ nlh = nlmsg_hdr(skb);
+ len = nlmsg_len(nlh);
+
+ if (len < (int)sizeof(struct cn_msg) ||
+ skb->len < nlh->nlmsg_len ||
+ len > CONNECTOR_MAX_MSG_SIZE)
+ return;
+
+ err = cn_call_callback(skb_get(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 __maybe_unused 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 struct cn_dev cdev = {
+ .input = cn_rx_skb,
+};
+
+static int cn_init(void)
+{
+ struct cn_dev *dev = &cdev;
+ struct netlink_kernel_cfg cfg = {
+ .groups = CN_NETLINK_USERS + 0xf,
+ .input = dev->input,
+ };
+
+ dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg);
+ 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_create_single("connector", S_IRUGO, init_net.proc_net, cn_proc_show);
+
+ return 0;
+}
+
+static void cn_fini(void)
+{
+ struct cn_dev *dev = &cdev;
+
+ cn_already_initialized = 0;
+
+ remove_proc_entry("connector", init_net.proc_net);
+
+ cn_queue_free_dev(dev->cbdev);
+ netlink_kernel_release(dev->nls);
+}
+
+subsys_initcall(cn_init);
+module_exit(cn_fini);