[net-next-2.6.git] / net / netlink / genetlink.c

/*
 * NETLINK      Generic Netlink Family
 *
 * 		Authors:	Jamal Hadi Salim
 * 				Thomas Graf <tgraf@suug.ch>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/mutex.h>
#include <net/sock.h>
#include <net/genetlink.h>

struct sock *genl_sock = NULL;

static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */

static void genl_lock(void)
{
	mutex_lock(&genl_mutex);
}

static int genl_trylock(void)
{
	return !mutex_trylock(&genl_mutex);
}

static void genl_unlock(void)
{
	mutex_unlock(&genl_mutex);

	if (genl_sock && genl_sock->sk_receive_queue.qlen)
		genl_sock->sk_data_ready(genl_sock, 0);
}

#define GENL_FAM_TAB_SIZE	16
#define GENL_FAM_TAB_MASK	(GENL_FAM_TAB_SIZE - 1)

static struct list_head family_ht[GENL_FAM_TAB_SIZE];

static int genl_ctrl_event(int event, void *data);

static inline unsigned int genl_family_hash(unsigned int id)
{
	return id & GENL_FAM_TAB_MASK;
}

static inline struct list_head *genl_family_chain(unsigned int id)
{
	return &family_ht[genl_family_hash(id)];
}

static struct genl_family *genl_family_find_byid(unsigned int id)
{
	struct genl_family *f;

	list_for_each_entry(f, genl_family_chain(id), family_list)
		if (f->id == id)
			return f;

	return NULL;
}

static struct genl_family *genl_family_find_byname(char *name)
{
	struct genl_family *f;
	int i;

	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
		list_for_each_entry(f, genl_family_chain(i), family_list)
			if (strcmp(f->name, name) == 0)
				return f;

	return NULL;
}

static struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
{
	struct genl_ops *ops;

	list_for_each_entry(ops, &family->ops_list, ops_list)
		if (ops->cmd == cmd)
			return ops;

	return NULL;
}

/* Of course we are going to have problems once we hit
 * 2^16 alive types, but that can only happen by year 2K
*/
static inline u16 genl_generate_id(void)
{
	static u16 id_gen_idx;
	int overflowed = 0;

	do {
		if (id_gen_idx == 0)
			id_gen_idx = GENL_MIN_ID;

		if (++id_gen_idx > GENL_MAX_ID) {
			if (!overflowed) {
				overflowed = 1;
				id_gen_idx = 0;
				continue;
			} else
				return 0;
		}

	} while (genl_family_find_byid(id_gen_idx));

	return id_gen_idx;
}

/**
 * genl_register_ops - register generic netlink operations
 * @family: generic netlink family
 * @ops: operations to be registered
 *
 * Registers the specified operations and assigns them to the specified
 * family. Either a doit or dumpit callback must be specified or the
 * operation will fail. Only one operation structure per command
 * identifier may be registered.
 *
 * See include/net/genetlink.h for more documenation on the operations
 * structure.
 *
 * Returns 0 on success or a negative error code.
 */
int genl_register_ops(struct genl_family *family, struct genl_ops *ops)
{
	int err = -EINVAL;

	if (ops->dumpit == NULL && ops->doit == NULL)
		goto errout;

	if (genl_get_cmd(ops->cmd, family)) {
		err = -EEXIST;
		goto errout;
	}

	genl_lock();
	list_add_tail(&ops->ops_list, &family->ops_list);
	genl_unlock();

	genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
	err = 0;
errout:
	return err;
}

/**
 * genl_unregister_ops - unregister generic netlink operations
 * @family: generic netlink family
 * @ops: operations to be unregistered
 *
 * Unregisters the specified operations and unassigns them from the
 * specified family. The operation blocks until the current message
 * processing has finished and doesn't start again until the
 * unregister process has finished.
 *
 * Note: It is not necessary to unregister all operations before
 *       unregistering the family, unregistering the family will cause
 *       all assigned operations to be unregistered automatically.
 *
 * Returns 0 on success or a negative error code.
 */
int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
{
	struct genl_ops *rc;

	genl_lock();
	list_for_each_entry(rc, &family->ops_list, ops_list) {
		if (rc == ops) {
			list_del(&ops->ops_list);
			genl_unlock();
			genl_ctrl_event(CTRL_CMD_DELOPS, ops);
			return 0;
		}
	}
	genl_unlock();

	return -ENOENT;
}

/**
 * genl_register_family - register a generic netlink family
 * @family: generic netlink family
 *
 * Registers the specified family after validating it first. Only one
 * family may be registered with the same family name or identifier.
 * The family id may equal GENL_ID_GENERATE causing an unique id to
 * be automatically generated and assigned.
 *
 * Return 0 on success or a negative error code.
 */
int genl_register_family(struct genl_family *family)
{
	int err = -EINVAL;

	if (family->id && family->id < GENL_MIN_ID)
		goto errout;

	if (family->id > GENL_MAX_ID)
		goto errout;

	INIT_LIST_HEAD(&family->ops_list);

	genl_lock();

	if (genl_family_find_byname(family->name)) {
		err = -EEXIST;
		goto errout_locked;
	}

	if (genl_family_find_byid(family->id)) {
		err = -EEXIST;
		goto errout_locked;
	}

	if (family->id == GENL_ID_GENERATE) {
		u16 newid = genl_generate_id();

		if (!newid) {
			err = -ENOMEM;
			goto errout_locked;
		}

		family->id = newid;
	}

	if (family->maxattr) {
		family->attrbuf = kmalloc((family->maxattr+1) *
					sizeof(struct nlattr *), GFP_KERNEL);
		if (family->attrbuf == NULL) {
			err = -ENOMEM;
			goto errout_locked;
		}
	} else
		family->attrbuf = NULL;

	list_add_tail(&family->family_list, genl_family_chain(family->id));
	genl_unlock();

	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);

	return 0;

errout_locked:
	genl_unlock();
errout:
	return err;
}

/**
 * genl_unregister_family - unregister generic netlink family
 * @family: generic netlink family
 *
 * Unregisters the specified family.
 *
 * Returns 0 on success or a negative error code.
 */
int genl_unregister_family(struct genl_family *family)
{
	struct genl_family *rc;

	genl_lock();

	list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
		if (family->id != rc->id || strcmp(rc->name, family->name))
			continue;

		list_del(&rc->family_list);
		INIT_LIST_HEAD(&family->ops_list);
		genl_unlock();

		kfree(family->attrbuf);
		genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
		return 0;
	}

	genl_unlock();

	return -ENOENT;
}

static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
			       int *errp)
{
	struct genl_ops *ops;
	struct genl_family *family;
	struct genl_info info;
	struct genlmsghdr *hdr = nlmsg_data(nlh);
	int hdrlen, err = -EINVAL;

	if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
		goto ignore;

	if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
		goto ignore;

       	family = genl_family_find_byid(nlh->nlmsg_type);
	if (family == NULL) {
		err = -ENOENT;
		goto errout;
	}

	hdrlen = GENL_HDRLEN + family->hdrsize;
	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
		goto errout;

	ops = genl_get_cmd(hdr->cmd, family);
	if (ops == NULL) {
		err = -EOPNOTSUPP;
		goto errout;
	}

	if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
		err = -EPERM;
		goto errout;
	}

	if (nlh->nlmsg_flags & NLM_F_DUMP) {
		if (ops->dumpit == NULL) {
			err = -EOPNOTSUPP;
			goto errout;
		}

		*errp = err = netlink_dump_start(genl_sock, skb, nlh,
						 ops->dumpit, NULL);
		if (err == 0)
			skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
					  skb->len));
		return -1;
	}

	if (ops->doit == NULL) {
		err = -EOPNOTSUPP;
		goto errout;
	}

	if (family->attrbuf) {
		err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
				  ops->policy);
		if (err < 0)
			goto errout;
	}

	info.snd_seq = nlh->nlmsg_seq;
	info.snd_pid = NETLINK_CB(skb).pid;
	info.nlhdr = nlh;
	info.genlhdr = nlmsg_data(nlh);
	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
	info.attrs = family->attrbuf;

	*errp = err = ops->doit(skb, &info);
	return err;

ignore:
	return 0;

errout:
	*errp = err;
	return -1;
}

static void genl_rcv(struct sock *sk, int len)
{
	unsigned int qlen = 0;

	do {
		if (genl_trylock())
			return;
		netlink_run_queue(sk, &qlen, genl_rcv_msg);
		genl_unlock();
	} while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
}

/**************************************************************************
 * Controller
 **************************************************************************/

static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
			  u32 flags, struct sk_buff *skb, u8 cmd)
{
	struct nlattr *nla_ops;
	struct genl_ops *ops;
	void *hdr;
	int idx = 1;

	hdr = genlmsg_put(skb, pid, seq, GENL_ID_CTRL, 0, flags, cmd,
			  family->version);
	if (hdr == NULL)
		return -1;

	NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
	NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
	NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
	NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
	NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);

	nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
	if (nla_ops == NULL)
		goto nla_put_failure;

	list_for_each_entry(ops, &family->ops_list, ops_list) {
		struct nlattr *nest;

		nest = nla_nest_start(skb, idx++);
		if (nest == NULL)
			goto nla_put_failure;

		NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
		NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);

		if (ops->policy)
			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_POLICY);

		if (ops->doit)
			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DOIT);

		if (ops->dumpit)
			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DUMPIT);

		nla_nest_end(skb, nest);
	}

	nla_nest_end(skb, nla_ops);

	return genlmsg_end(skb, hdr);

nla_put_failure:
	return genlmsg_cancel(skb, hdr);
}

static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
{

	int i, n = 0;
	struct genl_family *rt;
	int chains_to_skip = cb->args[0];
	int fams_to_skip = cb->args[1];

	if (chains_to_skip != 0)
		genl_lock();

	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
		if (i < chains_to_skip)
			continue;
		n = 0;
		list_for_each_entry(rt, genl_family_chain(i), family_list) {
			if (++n < fams_to_skip)
				continue;
			if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
					   cb->nlh->nlmsg_seq, NLM_F_MULTI,
					   skb, CTRL_CMD_NEWFAMILY) < 0)
				goto errout;
		}

		fams_to_skip = 0;
	}

errout:
	if (chains_to_skip != 0)
		genl_unlock();

	cb->args[0] = i;
	cb->args[1] = n;

	return skb->len;
}

static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
				      int seq, u8 cmd)
{
	struct sk_buff *skb;
	int err;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (skb == NULL)
		return ERR_PTR(-ENOBUFS);

	err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
	if (err < 0) {
		nlmsg_free(skb);
		return ERR_PTR(err);
	}

	return skb;
}

static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
	[CTRL_ATTR_FAMILY_ID]	= { .type = NLA_U16 },
	[CTRL_ATTR_FAMILY_NAME]	= { .type = NLA_NUL_STRING,
				    .len = GENL_NAMSIZ - 1 },
};

static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
{
	struct sk_buff *msg;
	struct genl_family *res = NULL;
	int err = -EINVAL;

	if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
		u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
		res = genl_family_find_byid(id);
	}

	if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
		char *name;

		name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
		res = genl_family_find_byname(name);
	}

	if (res == NULL) {
		err = -ENOENT;
		goto errout;
	}

	msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
			     CTRL_CMD_NEWFAMILY);
	if (IS_ERR(msg)) {
		err = PTR_ERR(msg);
		goto errout;
	}

	err = genlmsg_unicast(msg, info->snd_pid);
errout:
	return err;
}

static int genl_ctrl_event(int event, void *data)
{
	struct sk_buff *msg;

	if (genl_sock == NULL)
		return 0;

	switch (event) {
	case CTRL_CMD_NEWFAMILY:
	case CTRL_CMD_DELFAMILY:
		msg = ctrl_build_msg(data, 0, 0, event);
		if (IS_ERR(msg))
			return PTR_ERR(msg);

		genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
		break;
	}

	return 0;
}

static struct genl_ops genl_ctrl_ops = {
	.cmd		= CTRL_CMD_GETFAMILY,
	.doit		= ctrl_getfamily,
	.dumpit		= ctrl_dumpfamily,
	.policy		= ctrl_policy,
};

static struct genl_family genl_ctrl = {
	.id = GENL_ID_CTRL,
	.name = "nlctrl",
	.version = 0x1,
	.maxattr = CTRL_ATTR_MAX,
};

static int __init genl_init(void)
{
	int i, err;

	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
		INIT_LIST_HEAD(&family_ht[i]);

	err = genl_register_family(&genl_ctrl);
	if (err < 0)
		goto errout;

	err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
	if (err < 0)
		goto errout_register;

	netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
	genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
					  genl_rcv, THIS_MODULE);
	if (genl_sock == NULL)
		panic("GENL: Cannot initialize generic netlink\n");

	return 0;

errout_register:
	genl_unregister_family(&genl_ctrl);
errout:
	panic("GENL: Cannot register controller: %d\n", err);
}

subsys_initcall(genl_init);

EXPORT_SYMBOL(genl_sock);
EXPORT_SYMBOL(genl_register_ops);
EXPORT_SYMBOL(genl_unregister_ops);
EXPORT_SYMBOL(genl_register_family);
EXPORT_SYMBOL(genl_unregister_family);
Commit	Line	Data
482a8524 TG	1	/*
	2	* NETLINK Generic Netlink Family
	3	*
	4	* Authors: Jamal Hadi Salim
	5	* Thomas Graf <tgraf@suug.ch>
	6	*/
	7
482a8524 TG	8	#include <linux/module.h>
	9	#include <linux/kernel.h>
	10	#include <linux/errno.h>
	11	#include <linux/types.h>
	12	#include <linux/socket.h>
	13	#include <linux/string.h>
	14	#include <linux/skbuff.h>
14cc3e2b	15	#include <linux/mutex.h>
482a8524 TG	16	#include <net/sock.h>
	17	#include <net/genetlink.h>
	18
	19	struct sock *genl_sock = NULL;
	20
14cc3e2b	21	static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
482a8524 TG	22
	23	static void genl_lock(void)
	24	{
14cc3e2b	25	mutex_lock(&genl_mutex);
482a8524 TG	26	}
	27
	28	static int genl_trylock(void)
	29	{
14cc3e2b	30	return !mutex_trylock(&genl_mutex);
482a8524 TG	31	}
	32
	33	static void genl_unlock(void)
	34	{
14cc3e2b	35	mutex_unlock(&genl_mutex);
482a8524 TG	36
	37	if (genl_sock && genl_sock->sk_receive_queue.qlen)
	38	genl_sock->sk_data_ready(genl_sock, 0);
	39	}
	40
	41	#define GENL_FAM_TAB_SIZE 16
	42	#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
	43
	44	static struct list_head family_ht[GENL_FAM_TAB_SIZE];
	45
	46	static int genl_ctrl_event(int event, void *data);
	47
	48	static inline unsigned int genl_family_hash(unsigned int id)
	49	{
	50	return id & GENL_FAM_TAB_MASK;
	51	}
	52
	53	static inline struct list_head *genl_family_chain(unsigned int id)
	54	{
	55	return &family_ht[genl_family_hash(id)];
	56	}
	57
	58	static struct genl_family *genl_family_find_byid(unsigned int id)
	59	{
	60	struct genl_family *f;
	61
	62	list_for_each_entry(f, genl_family_chain(id), family_list)
	63	if (f->id == id)
	64	return f;
	65
	66	return NULL;
	67	}
	68
	69	static struct genl_family genl_family_find_byname(char name)
	70	{
	71	struct genl_family *f;
	72	int i;
	73
	74	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
	75	list_for_each_entry(f, genl_family_chain(i), family_list)
	76	if (strcmp(f->name, name) == 0)
	77	return f;
	78
	79	return NULL;
	80	}
	81
	82	static struct genl_ops genl_get_cmd(u8 cmd, struct genl_family family)
	83	{
	84	struct genl_ops *ops;
	85
	86	list_for_each_entry(ops, &family->ops_list, ops_list)
	87	if (ops->cmd == cmd)
	88	return ops;
	89
	90	return NULL;
	91	}
	92
	93	/* Of course we are going to have problems once we hit
	94	* 2^16 alive types, but that can only happen by year 2K
	95	*/
	96	static inline u16 genl_generate_id(void)
	97	{
	98	static u16 id_gen_idx;
	99	int overflowed = 0;
100
101	do {
102	if (id_gen_idx == 0)
103	id_gen_idx = GENL_MIN_ID;
104
105	if (++id_gen_idx > GENL_MAX_ID) {
106	if (!overflowed) {
107	overflowed = 1;
108	id_gen_idx = 0;
109	continue;
110	} else
111	return 0;
112	}
113
114	} while (genl_family_find_byid(id_gen_idx));
115
116	return id_gen_idx;
117	}
118
119	/**
120	* genl_register_ops - register generic netlink operations
121	* @family: generic netlink family
122	* @ops: operations to be registered
123	*
124	* Registers the specified operations and assigns them to the specified
125	* family. Either a doit or dumpit callback must be specified or the
126	* operation will fail. Only one operation structure per command
127	* identifier may be registered.
128	*
129	* See include/net/genetlink.h for more documenation on the operations
130	* structure.
131	*
132	* Returns 0 on success or a negative error code.
133	*/
134	int genl_register_ops(struct genl_family family, struct genl_ops ops)
135	{
136	int err = -EINVAL;
137
138	if (ops->dumpit == NULL && ops->doit == NULL)
139	goto errout;
140
141	if (genl_get_cmd(ops->cmd, family)) {
142	err = -EEXIST;
143	goto errout;
144	}
145
146	genl_lock();
147	list_add_tail(&ops->ops_list, &family->ops_list);
148	genl_unlock();
149
150	genl_ctrl_event(CTRL_CMD_NEWOPS, ops);
151	err = 0;
152	errout:
153	return err;
154	}
155
156	/**
157	* genl_unregister_ops - unregister generic netlink operations
158	* @family: generic netlink family
159	* @ops: operations to be unregistered
160	*
161	* Unregisters the specified operations and unassigns them from the
162	* specified family. The operation blocks until the current message
163	* processing has finished and doesn't start again until the
164	* unregister process has finished.
165	*
166	* Note: It is not necessary to unregister all operations before
167	* unregistering the family, unregistering the family will cause
168	* all assigned operations to be unregistered automatically.
169	*
170	* Returns 0 on success or a negative error code.
171	*/
172	int genl_unregister_ops(struct genl_family family, struct genl_ops ops)
173	{
174	struct genl_ops *rc;
175
176	genl_lock();
177	list_for_each_entry(rc, &family->ops_list, ops_list) {
178	if (rc == ops) {
179	list_del(&ops->ops_list);
180	genl_unlock();
181	genl_ctrl_event(CTRL_CMD_DELOPS, ops);
182	return 0;
183	}
184	}
185	genl_unlock();
186
187	return -ENOENT;
188	}
189
190	/**
191	* genl_register_family - register a generic netlink family
192	* @family: generic netlink family
193	*
194	* Registers the specified family after validating it first. Only one
195	* family may be registered with the same family name or identifier.
196	* The family id may equal GENL_ID_GENERATE causing an unique id to
197	* be automatically generated and assigned.
198	*
199	* Return 0 on success or a negative error code.
200	*/
201	int genl_register_family(struct genl_family *family)
202	{
203	int err = -EINVAL;
204
205	if (family->id && family->id < GENL_MIN_ID)
206	goto errout;
207
208	if (family->id > GENL_MAX_ID)
209	goto errout;
210
211	INIT_LIST_HEAD(&family->ops_list);
212
213	genl_lock();
214
215	if (genl_family_find_byname(family->name)) {
216	err = -EEXIST;
217	goto errout_locked;
218	}
219
220	if (genl_family_find_byid(family->id)) {
221	err = -EEXIST;
222	goto errout_locked;
223	}
224
482a8524 TG	225	if (family->id == GENL_ID_GENERATE) {
	226	u16 newid = genl_generate_id();
	227
	228	if (!newid) {
	229	err = -ENOMEM;
	230	goto errout_locked;
	231	}
	232
	233	family->id = newid;
	234	}
	235
	236	if (family->maxattr) {
	237	family->attrbuf = kmalloc((family->maxattr+1) *
	238	sizeof(struct nlattr *), GFP_KERNEL);
	239	if (family->attrbuf == NULL) {
	240	err = -ENOMEM;
e200bd80	241	goto errout_locked;
482a8524 TG	242	}
	243	} else
	244	family->attrbuf = NULL;
	245
	246	list_add_tail(&family->family_list, genl_family_chain(family->id));
	247	genl_unlock();
	248
	249	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family);
	250
	251	return 0;
	252
	253	errout_locked:
	254	genl_unlock();
	255	errout:
	256	return err;
	257	}
	258
	259	/**
	260	* genl_unregister_family - unregister generic netlink family
	261	* @family: generic netlink family
	262	*
	263	* Unregisters the specified family.
	264	*
	265	* Returns 0 on success or a negative error code.
	266	*/
	267	int genl_unregister_family(struct genl_family *family)
	268	{
	269	struct genl_family *rc;
	270
	271	genl_lock();
	272
	273	list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
	274	if (family->id != rc->id \|\| strcmp(rc->name, family->name))
	275	continue;
	276
	277	list_del(&rc->family_list);
	278	INIT_LIST_HEAD(&family->ops_list);
	279	genl_unlock();
	280
482a8524 TG	281	kfree(family->attrbuf);
	282	genl_ctrl_event(CTRL_CMD_DELFAMILY, family);
	283	return 0;
	284	}
	285
	286	genl_unlock();
	287
	288	return -ENOENT;
	289	}
	290
e200bd80	291	static int genl_rcv_msg(struct sk_buff skb, struct nlmsghdr nlh,
482a8524 TG	292	int *errp)
	293	{
	294	struct genl_ops *ops;
	295	struct genl_family *family;
	296	struct genl_info info;
	297	struct genlmsghdr *hdr = nlmsg_data(nlh);
	298	int hdrlen, err = -EINVAL;
	299
	300	if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
	301	goto ignore;
	302
	303	if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
	304	goto ignore;
	305
	306	family = genl_family_find_byid(nlh->nlmsg_type);
	307	if (family == NULL) {
	308	err = -ENOENT;
	309	goto errout;
	310	}
	311
	312	hdrlen = GENL_HDRLEN + family->hdrsize;
	313	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
	314	goto errout;
	315
	316	ops = genl_get_cmd(hdr->cmd, family);
	317	if (ops == NULL) {
	318	err = -EOPNOTSUPP;
	319	goto errout;
	320	}
	321
c7bdb545	322	if ((ops->flags & GENL_ADMIN_PERM) && security_netlink_recv(skb, CAP_NET_ADMIN)) {
482a8524 TG	323	err = -EPERM;
	324	goto errout;
	325	}
	326
	327	if (nlh->nlmsg_flags & NLM_F_DUMP) {
	328	if (ops->dumpit == NULL) {
	329	err = -EOPNOTSUPP;
	330	goto errout;
	331	}
	332
	333	*errp = err = netlink_dump_start(genl_sock, skb, nlh,
	334	ops->dumpit, NULL);
	335	if (err == 0)
	336	skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
	337	skb->len));
	338	return -1;
	339	}
	340
	341	if (ops->doit == NULL) {
	342	err = -EOPNOTSUPP;
	343	goto errout;
	344	}
	345
	346	if (family->attrbuf) {
	347	err = nlmsg_parse(nlh, hdrlen, family->attrbuf, family->maxattr,
	348	ops->policy);
	349	if (err < 0)
	350	goto errout;
	351	}
	352
	353	info.snd_seq = nlh->nlmsg_seq;
	354	info.snd_pid = NETLINK_CB(skb).pid;
	355	info.nlhdr = nlh;
	356	info.genlhdr = nlmsg_data(nlh);
	357	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
	358	info.attrs = family->attrbuf;
	359
	360	*errp = err = ops->doit(skb, &info);
	361	return err;
	362
	363	ignore:
	364	return 0;
	365
	366	errout:
	367	*errp = err;
	368	return -1;
	369	}
	370
	371	static void genl_rcv(struct sock *sk, int len)
	372	{
	373	unsigned int qlen = 0;
	374
	375	do {
	376	if (genl_trylock())
	377	return;
e200bd80	378	netlink_run_queue(sk, &qlen, genl_rcv_msg);
482a8524 TG	379	genl_unlock();
	380	} while (qlen && genl_sock && genl_sock->sk_receive_queue.qlen);
	381	}
	382
	383	/**************************************************************************
	384	* Controller
	385	**************************************************************************/
	386
	387	static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
	388	u32 flags, struct sk_buff *skb, u8 cmd)
	389	{
eb328111 TG	390	struct nlattr *nla_ops;
eb328111 TG	391	struct genl_ops *ops;
482a8524	392	void *hdr;
eb328111	393	int idx = 1;
482a8524 TG	394
	395	hdr = genlmsg_put(skb, pid, seq, GENL_ID_CTRL, 0, flags, cmd,
	396	family->version);
	397	if (hdr == NULL)
	398	return -1;
	399
	400	NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);
	401	NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);
eb328111 TG	402	NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);
	403	NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);
	404	NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);
	405
	406	nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
	407	if (nla_ops == NULL)
	408	goto nla_put_failure;
	409
	410	list_for_each_entry(ops, &family->ops_list, ops_list) {
	411	struct nlattr *nest;
	412
	413	nest = nla_nest_start(skb, idx++);
	414	if (nest == NULL)
	415	goto nla_put_failure;
	416
	417	NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);
	418	NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);
	419
	420	if (ops->policy)
	421	NLA_PUT_FLAG(skb, CTRL_ATTR_OP_POLICY);
	422
	423	if (ops->doit)
	424	NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DOIT);
	425
	426	if (ops->dumpit)
	427	NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DUMPIT);
	428
	429	nla_nest_end(skb, nest);
	430	}
	431
	432	nla_nest_end(skb, nla_ops);
482a8524 TG	433
	434	return genlmsg_end(skb, hdr);
	435
	436	nla_put_failure:
	437	return genlmsg_cancel(skb, hdr);
	438	}
	439
	440	static int ctrl_dumpfamily(struct sk_buff skb, struct netlink_callback cb)
	441	{
	442
	443	int i, n = 0;
	444	struct genl_family *rt;
	445	int chains_to_skip = cb->args[0];
	446	int fams_to_skip = cb->args[1];
	447
eb328111 TG	448	if (chains_to_skip != 0)
	449	genl_lock();
	450
482a8524 TG	451	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
	452	if (i < chains_to_skip)
	453	continue;
	454	n = 0;
	455	list_for_each_entry(rt, genl_family_chain(i), family_list) {
	456	if (++n < fams_to_skip)
	457	continue;
	458	if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
	459	cb->nlh->nlmsg_seq, NLM_F_MULTI,
	460	skb, CTRL_CMD_NEWFAMILY) < 0)
	461	goto errout;
	462	}
	463
	464	fams_to_skip = 0;
	465	}
	466
	467	errout:
eb328111 TG	468	if (chains_to_skip != 0)
	469	genl_unlock();
	470
482a8524 TG	471	cb->args[0] = i;
	472	cb->args[1] = n;
	473
	474	return skb->len;
	475	}
	476
	477	static struct sk_buff ctrl_build_msg(struct genl_family family, u32 pid,
b461d2f2	478	int seq, u8 cmd)
482a8524 TG	479	{
	480	struct sk_buff *skb;
	481	int err;
	482
339bf98f	483	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
482a8524 TG	484	if (skb == NULL)
	485	return ERR_PTR(-ENOBUFS);
	486
	487	err = ctrl_fill_info(family, pid, seq, 0, skb, cmd);
	488	if (err < 0) {
	489	nlmsg_free(skb);
	490	return ERR_PTR(err);
	491	}
	492
	493	return skb;
	494	}
	495
	496	static struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] __read_mostly = {
	497	[CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
5176f91e TG	498	[CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
5176f91e TG	499	.len = GENL_NAMSIZ - 1 },
482a8524 TG	500	};
	501
	502	static int ctrl_getfamily(struct sk_buff skb, struct genl_info info)
	503	{
	504	struct sk_buff *msg;
	505	struct genl_family *res = NULL;
	506	int err = -EINVAL;
	507
	508	if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
	509	u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
	510	res = genl_family_find_byid(id);
	511	}
	512
	513	if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
5176f91e	514	char *name;
482a8524	515
5176f91e	516	name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
482a8524 TG	517	res = genl_family_find_byname(name);
	518	}
	519
	520	if (res == NULL) {
	521	err = -ENOENT;
	522	goto errout;
	523	}
	524
	525	msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
	526	CTRL_CMD_NEWFAMILY);
	527	if (IS_ERR(msg)) {
	528	err = PTR_ERR(msg);
	529	goto errout;
	530	}
	531
	532	err = genlmsg_unicast(msg, info->snd_pid);
	533	errout:
	534	return err;
	535	}
	536
	537	static int genl_ctrl_event(int event, void *data)
	538	{
	539	struct sk_buff *msg;
	540
	541	if (genl_sock == NULL)
	542	return 0;
	543
	544	switch (event) {
	545	case CTRL_CMD_NEWFAMILY:
	546	case CTRL_CMD_DELFAMILY:
	547	msg = ctrl_build_msg(data, 0, 0, event);
	548	if (IS_ERR(msg))
	549	return PTR_ERR(msg);
	550
d387f6ad	551	genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
482a8524 TG	552	break;
	553	}
	554
	555	return 0;
	556	}
	557
	558	static struct genl_ops genl_ctrl_ops = {
	559	.cmd = CTRL_CMD_GETFAMILY,
	560	.doit = ctrl_getfamily,
	561	.dumpit = ctrl_dumpfamily,
	562	.policy = ctrl_policy,
	563	};
	564
	565	static struct genl_family genl_ctrl = {
	566	.id = GENL_ID_CTRL,
	567	.name = "nlctrl",
	568	.version = 0x1,
	569	.maxattr = CTRL_ATTR_MAX,
482a8524 TG	570	};
	571
	572	static int __init genl_init(void)
	573	{
	574	int i, err;
	575
	576	for (i = 0; i < GENL_FAM_TAB_SIZE; i++)
	577	INIT_LIST_HEAD(&family_ht[i]);
	578
	579	err = genl_register_family(&genl_ctrl);
	580	if (err < 0)
	581	goto errout;
	582
	583	err = genl_register_ops(&genl_ctrl, &genl_ctrl_ops);
	584	if (err < 0)
	585	goto errout_register;
	586
	587	netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
	588	genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
	589	genl_rcv, THIS_MODULE);
e200bd80	590	if (genl_sock == NULL)
482a8524	591	panic("GENL: Cannot initialize generic netlink\n");
482a8524 TG	592
	593	return 0;
	594
	595	errout_register:
	596	genl_unregister_family(&genl_ctrl);
	597	errout:
	598	panic("GENL: Cannot register controller: %d\n", err);
482a8524 TG	599	}
	600
	601	subsys_initcall(genl_init);
	602
	603	EXPORT_SYMBOL(genl_sock);
	604	EXPORT_SYMBOL(genl_register_ops);
	605	EXPORT_SYMBOL(genl_unregister_ops);
	606	EXPORT_SYMBOL(genl_register_family);
	607	EXPORT_SYMBOL(genl_unregister_family);