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-rw-r--r--Documentation/connector/Makefile16
-rw-r--r--Documentation/connector/cn_test.c201
-rw-r--r--Documentation/connector/connector.txt181
-rw-r--r--Documentation/connector/ucon.c250
4 files changed, 648 insertions, 0 deletions
diff --git a/Documentation/connector/Makefile b/Documentation/connector/Makefile
new file mode 100644
index 00000000..d98e4df9
--- /dev/null
+++ b/Documentation/connector/Makefile
@@ -0,0 +1,16 @@
+ifneq ($(CONFIG_CONNECTOR),)
+obj-m += cn_test.o
+endif
+
+# List of programs to build
+hostprogs-y := ucon
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
+
+HOSTCFLAGS_ucon.o += -I$(objtree)/usr/include
+
+all: modules
+
+modules clean:
+ $(MAKE) -C ../.. SUBDIRS=$(PWD) $@
diff --git a/Documentation/connector/cn_test.c b/Documentation/connector/cn_test.c
new file mode 100644
index 00000000..adcca036
--- /dev/null
+++ b/Documentation/connector/cn_test.c
@@ -0,0 +1,201 @@
+/*
+ * cn_test.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
+ */
+
+#define pr_fmt(fmt) "cn_test: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+
+#include <linux/connector.h>
+
+static struct cb_id cn_test_id = { CN_NETLINK_USERS + 3, 0x456 };
+static char cn_test_name[] = "cn_test";
+static struct sock *nls;
+static struct timer_list cn_test_timer;
+
+static void cn_test_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
+{
+ pr_info("%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,
+ msg->len ? (char *)msg->data : "");
+}
+
+/*
+ * Do not remove this function even if no one is using it as
+ * this is an example of how to get notifications about new
+ * connector user registration
+ */
+#if 0
+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) {
+ pr_err("failed to allocate new skb with size=%u\n", size);
+ return -ENOMEM;
+ }
+
+ nlh = nlmsg_put(skb, 0, 0x123, NLMSG_DONE, size - sizeof(*nlh), 0);
+ if (!nlh) {
+ kfree_skb(skb);
+ return -EMSGSIZE;
+ }
+
+ 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_group = ctl->group;
+ //netlink_broadcast(nls, skb, 0, ctl->group, GFP_ATOMIC);
+ netlink_unicast(nls, skb, 0, 0);
+
+ pr_info("request was sent: group=0x%x\n", ctl->group);
+
+ return 0;
+}
+#endif
+
+static u32 cn_test_timer_counter;
+static void cn_test_timer_func(unsigned long __data)
+{
+ struct cn_msg *m;
+ char data[32];
+
+ pr_debug("%s: timer fired with data %lu\n", __func__, __data);
+
+ m = kzalloc(sizeof(*m) + sizeof(data), GFP_ATOMIC);
+ if (m) {
+
+ 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_ATOMIC);
+ kfree(m);
+ }
+
+ cn_test_timer_counter++;
+
+ mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));
+}
+
+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;
+ }
+
+ setup_timer(&cn_test_timer, cn_test_timer_func, 0);
+ mod_timer(&cn_test_timer, jiffies + msecs_to_jiffies(1000));
+
+ pr_info("initialized with id={%u.%u}\n",
+ cn_test_id.idx, cn_test_id.val);
+
+ 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 <zbr@ioremap.net>");
+MODULE_DESCRIPTION("Connector's test module");
diff --git a/Documentation/connector/connector.txt b/Documentation/connector/connector.txt
new file mode 100644
index 00000000..e5c5f5e6
--- /dev/null
+++ b/Documentation/connector/connector.txt
@@ -0,0 +1,181 @@
+/*****************************************/
+Kernel Connector.
+/*****************************************/
+
+Kernel connector - new netlink based userspace <-> kernel space easy
+to use communication module.
+
+The Connector driver makes it easy to connect various agents using a
+netlink based network. One must register a callback and an identifier.
+When the driver receives a special netlink message with the appropriate
+identifier, the appropriate callback will be called.
+
+From the userspace point of view it's quite straightforward:
+
+ socket();
+ bind();
+ send();
+ recv();
+
+But if kernelspace wants to use the full power of such connections, the
+driver writer must create special sockets, must know about struct sk_buff
+handling, etc... The Connector driver 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) (struct cn_msg *, struct netlink_skb_parms *));
+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 the
+connector.h header for in-kernel usage. void (*callback) (void *) is a
+callback function which will be called when a message with above idx.val
+is received by the connector core. The 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) (struct cn_msg *, struct netlink_skb_parms *));
+
+ 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) (struct cn..) - connector's callback.
+ cn_msg and the sender's credentials
+
+
+void cn_del_callback(struct cb_id *id);
+
+ Unregisters new callback with connector core.
+
+ struct cb_id *id - unique connector's user identifier.
+
+
+int cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);
+
+ Sends message to the specified groups. It can be safely called from
+ softirq context, but may silently fail under strong memory pressure.
+ If there are no listeners for given group -ESRCH can be returned.
+
+ 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 its id.idx.
+
+/*****************************************/
+Protocol description.
+/*****************************************/
+
+The current framework offers a transport layer with fixed headers. The
+recommended protocol which uses such a header is as following:
+
+msg->seq and msg->ack are used to determine message genealogy. When
+someone sends a message, they use a locally unique sequence and random
+acknowledge number. The sequence number may be copied into
+nlmsghdr->nlmsg_seq too.
+
+The sequence number is incremented with each message sent.
+
+If you expect a reply to the message, then the sequence number in the
+received message MUST be the same as in the original message, and the
+acknowledge number MUST be the same + 1.
+
+If we receive a message and its sequence number is not equal to 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 its
+acknowledge is not equal to the acknowledge number in the original
+message + 1, then it is a new message.
+
+Obviously, the protocol header contains the above id.
+
+The connector allows event notification in the following form: kernel
+driver or userspace process can ask connector to notify it when
+selected ids will be turned on or off (registered or unregistered its
+callback). It is done by sending a special command to the connector
+driver (it also registers itself with id={-1, -1}).
+
+As example of this usage can be found in the cn_test.c module which
+uses the connector to request notification and to send messages.
+
+/*****************************************/
+Reliability.
+/*****************************************/
+
+Netlink itself is not a reliable protocol. That means that messages can
+be lost due to memory pressure or process' receiving queue overflowed,
+so caller is warned that it must be prepared. That is why the struct
+cn_msg [main connector's message header] contains u32 seq and u32 ack
+fields.
+
+/*****************************************/
+Userspace usage.
+/*****************************************/
+
+2.6.14 has a new netlink socket implementation, which by default does not
+allow people to send data to netlink groups other than 1.
+So, if you wish to use a netlink socket (for example using connector)
+with a different group number, the userspace application must subscribe to
+that group first. It can be achieved by the following pseudocode:
+
+s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+
+l_local.nl_family = AF_NETLINK;
+l_local.nl_groups = 12345;
+l_local.nl_pid = 0;
+
+if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
+ perror("bind");
+ close(s);
+ return -1;
+}
+
+{
+ int on = l_local.nl_groups;
+ setsockopt(s, 270, 1, &on, sizeof(on));
+}
+
+Where 270 above is SOL_NETLINK, and 1 is a NETLINK_ADD_MEMBERSHIP socket
+option. To drop a multicast subscription, one should call the above socket
+option with the NETLINK_DROP_MEMBERSHIP parameter which is defined as 0.
+
+2.6.14 netlink code only allows to select a group which is less or equal to
+the maximum group number, which is used at netlink_kernel_create() time.
+In case of connector it is CN_NETLINK_USERS + 0xf, so if you want to use
+group number 12345, you must increment CN_NETLINK_USERS to that number.
+Additional 0xf numbers are allocated to be used by non-in-kernel users.
+
+Due to this limitation, group 0xffffffff does not work now, so one can
+not use add/remove connector's group notifications, but as far as I know,
+only cn_test.c test module used it.
+
+Some work in netlink area is still being done, so things can be changed in
+2.6.15 timeframe, if it will happen, documentation will be updated for that
+kernel.
diff --git a/Documentation/connector/ucon.c b/Documentation/connector/ucon.c
new file mode 100644
index 00000000..4848db8c
--- /dev/null
+++ b/Documentation/connector/ucon.c
@@ -0,0 +1,250 @@
+/*
+ * ucon.c
+ *
+ * Copyright (c) 2004+ Evgeniy Polyakov <zbr@ioremap.net>
+ *
+ *
+ * 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 <asm/types.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <arpa/inet.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+#include <getopt.h>
+
+#include <linux/connector.h>
+
+#define DEBUG
+#define NETLINK_CONNECTOR 11
+
+/* Hopefully your userspace connector.h matches this kernel */
+#define CN_TEST_IDX CN_NETLINK_USERS + 3
+#define CN_TEST_VAL 0x456
+
+#ifdef DEBUG
+#define ulog(f, a...) fprintf(stdout, f, ##a)
+#else
+#define ulog(f, a...) do {} while (0)
+#endif
+
+static int need_exit;
+static __u32 seq;
+
+static int netlink_send(int s, struct cn_msg *msg)
+{
+ struct nlmsghdr *nlh;
+ unsigned int size;
+ int err;
+ char buf[128];
+ struct cn_msg *m;
+
+ size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
+
+ nlh = (struct nlmsghdr *)buf;
+ nlh->nlmsg_seq = seq++;
+ nlh->nlmsg_pid = getpid();
+ nlh->nlmsg_type = NLMSG_DONE;
+ nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
+ nlh->nlmsg_flags = 0;
+
+ m = NLMSG_DATA(nlh);
+#if 0
+ ulog("%s: [%08x.%08x] len=%u, seq=%u, ack=%u.\n",
+ __func__, msg->id.idx, msg->id.val, msg->len, msg->seq, msg->ack);
+#endif
+ memcpy(m, msg, sizeof(*m) + msg->len);
+
+ err = send(s, nlh, size, 0);
+ if (err == -1)
+ ulog("Failed to send: %s [%d].\n",
+ strerror(errno), errno);
+
+ return err;
+}
+
+static void usage(void)
+{
+ printf(
+ "Usage: ucon [options] [output file]\n"
+ "\n"
+ "\t-h\tthis help screen\n"
+ "\t-s\tsend buffers to the test module\n"
+ "\n"
+ "The default behavior of ucon is to subscribe to the test module\n"
+ "and wait for state messages. Any ones received are dumped to the\n"
+ "specified output file (or stdout). The test module is assumed to\n"
+ "have an id of {%u.%u}\n"
+ "\n"
+ "If you get no output, then verify the cn_test module id matches\n"
+ "the expected id above.\n"
+ , CN_TEST_IDX, CN_TEST_VAL
+ );
+}
+
+int main(int argc, char *argv[])
+{
+ int s;
+ char buf[1024];
+ int len;
+ struct nlmsghdr *reply;
+ struct sockaddr_nl l_local;
+ struct cn_msg *data;
+ FILE *out;
+ time_t tm;
+ struct pollfd pfd;
+ bool send_msgs = false;
+
+ while ((s = getopt(argc, argv, "hs")) != -1) {
+ switch (s) {
+ case 's':
+ send_msgs = true;
+ break;
+
+ case 'h':
+ usage();
+ return 0;
+
+ default:
+ /* getopt() outputs an error for us */
+ usage();
+ return 1;
+ }
+ }
+
+ if (argc != optind) {
+ out = fopen(argv[optind], "a+");
+ if (!out) {
+ ulog("Unable to open %s for writing: %s\n",
+ argv[1], strerror(errno));
+ out = stdout;
+ }
+ } else
+ out = stdout;
+
+ memset(buf, 0, sizeof(buf));
+
+ s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+ if (s == -1) {
+ perror("socket");
+ return -1;
+ }
+
+ l_local.nl_family = AF_NETLINK;
+ l_local.nl_groups = -1; /* bitmask of requested groups */
+ l_local.nl_pid = 0;
+
+ ulog("subscribing to %u.%u\n", CN_TEST_IDX, CN_TEST_VAL);
+
+ if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
+ perror("bind");
+ close(s);
+ return -1;
+ }
+
+#if 0
+ {
+ int on = 0x57; /* Additional group number */
+ setsockopt(s, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &on, sizeof(on));
+ }
+#endif
+ if (send_msgs) {
+ int i, j;
+
+ memset(buf, 0, sizeof(buf));
+
+ data = (struct cn_msg *)buf;
+
+ data->id.idx = CN_TEST_IDX;
+ data->id.val = CN_TEST_VAL;
+ data->seq = seq++;
+ data->ack = 0;
+ data->len = 0;
+
+ for (j=0; j<10; ++j) {
+ for (i=0; i<1000; ++i) {
+ len = netlink_send(s, data);
+ }
+
+ ulog("%d messages have been sent to %08x.%08x.\n", i, data->id.idx, data->id.val);
+ }
+
+ return 0;
+ }
+
+
+ pfd.fd = s;
+
+ while (!need_exit) {
+ pfd.events = POLLIN;
+ pfd.revents = 0;
+ switch (poll(&pfd, 1, -1)) {
+ case 0:
+ need_exit = 1;
+ break;
+ case -1:
+ if (errno != EINTR) {
+ need_exit = 1;
+ break;
+ }
+ continue;
+ }
+ if (need_exit)
+ break;
+
+ memset(buf, 0, sizeof(buf));
+ len = recv(s, buf, sizeof(buf), 0);
+ if (len == -1) {
+ perror("recv buf");
+ close(s);
+ return -1;
+ }
+ reply = (struct nlmsghdr *)buf;
+
+ switch (reply->nlmsg_type) {
+ case NLMSG_ERROR:
+ fprintf(out, "Error message received.\n");
+ fflush(out);
+ break;
+ case NLMSG_DONE:
+ data = (struct cn_msg *)NLMSG_DATA(reply);
+
+ time(&tm);
+ fprintf(out, "%.24s : [%x.%x] [%08u.%08u].\n",
+ ctime(&tm), data->id.idx, data->id.val, data->seq, data->ack);
+ fflush(out);
+ break;
+ default:
+ break;
+ }
+ }
+
+ close(s);
+ return 0;
+}