Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

2 files changed, 327 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.