Initial import

1 files changed, 1154 insertions, 0 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
new file mode 100644
index 000000000..2ed5f9647
--- /dev/null
+++ b/net/netlink/genetlink.c
@@ -0,0 +1,1154 @@
+/*
+ * NETLINK      Generic Netlink Family
+ *
+ * 		Authors:	Jamal Hadi Salim
+ * 				Thomas Graf <tgraf@suug.ch>
+ *				Johannes Berg <johannes@sipsolutions.net>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.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 <linux/bitmap.h>
+#include <linux/rwsem.h>
+#include <net/sock.h>
+#include <net/genetlink.h>
+
+static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
+static DECLARE_RWSEM(cb_lock);
+
+atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
+DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
+
+void genl_lock(void)
+{
+	mutex_lock(&genl_mutex);
+}
+EXPORT_SYMBOL(genl_lock);
+
+void genl_unlock(void)
+{
+	mutex_unlock(&genl_mutex);
+}
+EXPORT_SYMBOL(genl_unlock);
+
+#ifdef CONFIG_LOCKDEP
+int lockdep_genl_is_held(void)
+{
+	return lockdep_is_held(&genl_mutex);
+}
+EXPORT_SYMBOL(lockdep_genl_is_held);
+#endif
+
+static void genl_lock_all(void)
+{
+	down_write(&cb_lock);
+	genl_lock();
+}
+
+static void genl_unlock_all(void)
+{
+	genl_unlock();
+	up_write(&cb_lock);
+}
+
+#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];
+/*
+ * Bitmap of multicast groups that are currently in use.
+ *
+ * To avoid an allocation at boot of just one unsigned long,
+ * declare it global instead.
+ * Bit 0 is marked as already used since group 0 is invalid.
+ * Bit 1 is marked as already used since the drop-monitor code
+ * abuses the API and thinks it can statically use group 1.
+ * That group will typically conflict with other groups that
+ * any proper users use.
+ * Bit 16 is marked as used since it's used for generic netlink
+ * and the code no longer marks pre-reserved IDs as used.
+ * Bit 17 is marked as already used since the VFS quota code
+ * also abused this API and relied on family == group ID, we
+ * cater to that by giving it a static family and group ID.
+ * Bit 18 is marked as already used since the PMCRAID driver
+ * did the same thing as the VFS quota code (maybe copied?)
+ */
+static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
+				      BIT(GENL_ID_VFS_DQUOT) |
+				      BIT(GENL_ID_PMCRAID);
+static unsigned long *mc_groups = &mc_group_start;
+static unsigned long mc_groups_longs = 1;
+
+static int genl_ctrl_event(int event, struct genl_family *family,
+			   const struct genl_multicast_group *grp,
+			   int grp_id);
+
+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 const struct genl_ops *genl_get_cmd(u8 cmd, struct genl_family *family)
+{
+	int i;
+
+	for (i = 0; i < family->n_ops; i++)
+		if (family->ops[i].cmd == cmd)
+			return &family->ops[i];
+
+	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 u16 genl_generate_id(void)
+{
+	static u16 id_gen_idx = GENL_MIN_ID;
+	int i;
+
+	for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) {
+		if (id_gen_idx != GENL_ID_VFS_DQUOT &&
+		    id_gen_idx != GENL_ID_PMCRAID &&
+		    !genl_family_find_byid(id_gen_idx))
+			return id_gen_idx;
+		if (++id_gen_idx > GENL_MAX_ID)
+			id_gen_idx = GENL_MIN_ID;
+	}
+
+	return 0;
+}
+
+static int genl_allocate_reserve_groups(int n_groups, int *first_id)
+{
+	unsigned long *new_groups;
+	int start = 0;
+	int i;
+	int id;
+	bool fits;
+
+	do {
+		if (start == 0)
+			id = find_first_zero_bit(mc_groups,
+						 mc_groups_longs *
+						 BITS_PER_LONG);
+		else
+			id = find_next_zero_bit(mc_groups,
+						mc_groups_longs * BITS_PER_LONG,
+						start);
+
+		fits = true;
+		for (i = id;
+		     i < min_t(int, id + n_groups,
+			       mc_groups_longs * BITS_PER_LONG);
+		     i++) {
+			if (test_bit(i, mc_groups)) {
+				start = i;
+				fits = false;
+				break;
+			}
+		}
+
+		if (id >= mc_groups_longs * BITS_PER_LONG) {
+			unsigned long new_longs = mc_groups_longs +
+						  BITS_TO_LONGS(n_groups);
+			size_t nlen = new_longs * sizeof(unsigned long);
+
+			if (mc_groups == &mc_group_start) {
+				new_groups = kzalloc(nlen, GFP_KERNEL);
+				if (!new_groups)
+					return -ENOMEM;
+				mc_groups = new_groups;
+				*mc_groups = mc_group_start;
+			} else {
+				new_groups = krealloc(mc_groups, nlen,
+						      GFP_KERNEL);
+				if (!new_groups)
+					return -ENOMEM;
+				mc_groups = new_groups;
+				for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
+					mc_groups[mc_groups_longs + i] = 0;
+			}
+			mc_groups_longs = new_longs;
+		}
+	} while (!fits);
+
+	for (i = id; i < id + n_groups; i++)
+		set_bit(i, mc_groups);
+	*first_id = id;
+	return 0;
+}
+
+static struct genl_family genl_ctrl;
+
+static int genl_validate_assign_mc_groups(struct genl_family *family)
+{
+	int first_id;
+	int n_groups = family->n_mcgrps;
+	int err = 0, i;
+	bool groups_allocated = false;
+
+	if (!n_groups)
+		return 0;
+
+	for (i = 0; i < n_groups; i++) {
+		const struct genl_multicast_group *grp = &family->mcgrps[i];
+
+		if (WARN_ON(grp->name[0] == '\0'))
+			return -EINVAL;
+		if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
+			return -EINVAL;
+	}
+
+	/* special-case our own group and hacks */
+	if (family == &genl_ctrl) {
+		first_id = GENL_ID_CTRL;
+		BUG_ON(n_groups != 1);
+	} else if (strcmp(family->name, "NET_DM") == 0) {
+		first_id = 1;
+		BUG_ON(n_groups != 1);
+	} else if (family->id == GENL_ID_VFS_DQUOT) {
+		first_id = GENL_ID_VFS_DQUOT;
+		BUG_ON(n_groups != 1);
+	} else if (family->id == GENL_ID_PMCRAID) {
+		first_id = GENL_ID_PMCRAID;
+		BUG_ON(n_groups != 1);
+	} else {
+		groups_allocated = true;
+		err = genl_allocate_reserve_groups(n_groups, &first_id);
+		if (err)
+			return err;
+	}
+
+	family->mcgrp_offset = first_id;
+
+	/* if still initializing, can't and don't need to to realloc bitmaps */
+	if (!init_net.genl_sock)
+		return 0;
+
+	if (family->netnsok) {
+		struct net *net;
+
+		netlink_table_grab();
+		rcu_read_lock();
+		for_each_net_rcu(net) {
+			err = __netlink_change_ngroups(net->genl_sock,
+					mc_groups_longs * BITS_PER_LONG);
+			if (err) {
+				/*
+				 * No need to roll back, can only fail if
+				 * memory allocation fails and then the
+				 * number of _possible_ groups has been
+				 * increased on some sockets which is ok.
+				 */
+				break;
+			}
+		}
+		rcu_read_unlock();
+		netlink_table_ungrab();
+	} else {
+		err = netlink_change_ngroups(init_net.genl_sock,
+					     mc_groups_longs * BITS_PER_LONG);
+	}
+
+	if (groups_allocated && err) {
+		for (i = 0; i < family->n_mcgrps; i++)
+			clear_bit(family->mcgrp_offset + i, mc_groups);
+	}
+
+	return err;
+}
+
+static void genl_unregister_mc_groups(struct genl_family *family)
+{
+	struct net *net;
+	int i;
+
+	netlink_table_grab();
+	rcu_read_lock();
+	for_each_net_rcu(net) {
+		for (i = 0; i < family->n_mcgrps; i++)
+			__netlink_clear_multicast_users(
+				net->genl_sock, family->mcgrp_offset + i);
+	}
+	rcu_read_unlock();
+	netlink_table_ungrab();
+
+	for (i = 0; i < family->n_mcgrps; i++) {
+		int grp_id = family->mcgrp_offset + i;
+
+		if (grp_id != 1)
+			clear_bit(grp_id, mc_groups);
+		genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
+				&family->mcgrps[i], grp_id);
+	}
+}
+
+static int genl_validate_ops(const struct genl_family *family)
+{
+	const struct genl_ops *ops = family->ops;
+	unsigned int n_ops = family->n_ops;
+	int i, j;
+
+	if (WARN_ON(n_ops && !ops))
+		return -EINVAL;
+
+	if (!n_ops)
+		return 0;
+
+	for (i = 0; i < n_ops; i++) {
+		if (ops[i].dumpit == NULL && ops[i].doit == NULL)
+			return -EINVAL;
+		for (j = i + 1; j < n_ops; j++)
+			if (ops[i].cmd == ops[j].cmd)
+				return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * __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.
+ *
+ * The family's ops array must already be assigned, you can use the
+ * genl_register_family_with_ops() helper function.
+ *
+ * Return 0 on success or a negative error code.
+ */
+int __genl_register_family(struct genl_family *family)
+{
+	int err = -EINVAL, i;
+
+	if (family->id && family->id < GENL_MIN_ID)
+		goto errout;
+
+	if (family->id > GENL_MAX_ID)
+		goto errout;
+
+	err = genl_validate_ops(family);
+	if (err)
+		return err;
+
+	genl_lock_all();
+
+	if (genl_family_find_byname(family->name)) {
+		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;
+	} else if (genl_family_find_byid(family->id)) {
+		err = -EEXIST;
+		goto errout_locked;
+	}
+
+	if (family->maxattr && !family->parallel_ops) {
+		family->attrbuf = kmalloc((family->maxattr+1) *
+					sizeof(struct nlattr *), GFP_KERNEL);
+		if (family->attrbuf == NULL) {
+			err = -ENOMEM;
+			goto errout_locked;
+		}
+	} else
+		family->attrbuf = NULL;
+
+	err = genl_validate_assign_mc_groups(family);
+	if (err)
+		goto errout_locked;
+
+	list_add_tail(&family->family_list, genl_family_chain(family->id));
+	genl_unlock_all();
+
+	/* send all events */
+	genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
+	for (i = 0; i < family->n_mcgrps; i++)
+		genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
+				&family->mcgrps[i], family->mcgrp_offset + i);
+
+	return 0;
+
+errout_locked:
+	genl_unlock_all();
+errout:
+	return err;
+}
+EXPORT_SYMBOL(__genl_register_family);
+
+/**
+ * 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_all();
+
+	list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
+		if (family->id != rc->id || strcmp(rc->name, family->name))
+			continue;
+
+		genl_unregister_mc_groups(family);
+
+		list_del(&rc->family_list);
+		family->n_ops = 0;
+		up_write(&cb_lock);
+		wait_event(genl_sk_destructing_waitq,
+			   atomic_read(&genl_sk_destructing_cnt) == 0);
+		genl_unlock();
+
+		kfree(family->attrbuf);
+		genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
+		return 0;
+	}
+
+	genl_unlock_all();
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL(genl_unregister_family);
+
+/**
+ * genlmsg_new_unicast - Allocate generic netlink message for unicast
+ * @payload: size of the message payload
+ * @info: information on destination
+ * @flags: the type of memory to allocate
+ *
+ * Allocates a new sk_buff large enough to cover the specified payload
+ * plus required Netlink headers. Will check receiving socket for
+ * memory mapped i/o capability and use it if enabled. Will fall back
+ * to non-mapped skb if message size exceeds the frame size of the ring.
+ */
+struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info,
+				    gfp_t flags)
+{
+	size_t len = nlmsg_total_size(genlmsg_total_size(payload));
+
+	return netlink_alloc_skb(info->dst_sk, len, info->snd_portid, flags);
+}
+EXPORT_SYMBOL_GPL(genlmsg_new_unicast);
+
+/**
+ * genlmsg_put - Add generic netlink header to netlink message
+ * @skb: socket buffer holding the message
+ * @portid: netlink portid the message is addressed to
+ * @seq: sequence number (usually the one of the sender)
+ * @family: generic netlink family
+ * @flags: netlink message flags
+ * @cmd: generic netlink command
+ *
+ * Returns pointer to user specific header
+ */
+void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
+				struct genl_family *family, int flags, u8 cmd)
+{
+	struct nlmsghdr *nlh;
+	struct genlmsghdr *hdr;
+
+	nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
+			family->hdrsize, flags);
+	if (nlh == NULL)
+		return NULL;
+
+	hdr = nlmsg_data(nlh);
+	hdr->cmd = cmd;
+	hdr->version = family->version;
+	hdr->reserved = 0;
+
+	return (char *) hdr + GENL_HDRLEN;
+}
+EXPORT_SYMBOL(genlmsg_put);
+
+static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	/* our ops are always const - netlink API doesn't propagate that */
+	const struct genl_ops *ops = cb->data;
+	int rc;
+
+	genl_lock();
+	rc = ops->dumpit(skb, cb);
+	genl_unlock();
+	return rc;
+}
+
+static int genl_lock_done(struct netlink_callback *cb)
+{
+	/* our ops are always const - netlink API doesn't propagate that */
+	const struct genl_ops *ops = cb->data;
+	int rc = 0;
+
+	if (ops->done) {
+		genl_lock();
+		rc = ops->done(cb);
+		genl_unlock();
+	}
+	return rc;
+}
+
+static int genl_family_rcv_msg(struct genl_family *family,
+			       struct sk_buff *skb,
+			       struct nlmsghdr *nlh)
+{
+	const struct genl_ops *ops;
+	struct net *net = sock_net(skb->sk);
+	struct genl_info info;
+	struct genlmsghdr *hdr = nlmsg_data(nlh);
+	struct nlattr **attrbuf;
+	int hdrlen, err;
+
+	/* this family doesn't exist in this netns */
+	if (!family->netnsok && !net_eq(net, &init_net))
+		return -ENOENT;
+
+	hdrlen = GENL_HDRLEN + family->hdrsize;
+	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+		return -EINVAL;
+
+	ops = genl_get_cmd(hdr->cmd, family);
+	if (ops == NULL)
+		return -EOPNOTSUPP;
+
+	if ((ops->flags & GENL_ADMIN_PERM) &&
+	    !netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
+		int rc;
+
+		if (ops->dumpit == NULL)
+			return -EOPNOTSUPP;
+
+		if (!family->parallel_ops) {
+			struct netlink_dump_control c = {
+				.module = family->module,
+				/* we have const, but the netlink API doesn't */
+				.data = (void *)ops,
+				.dump = genl_lock_dumpit,
+				.done = genl_lock_done,
+			};
+
+			genl_unlock();
+			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+			genl_lock();
+
+		} else {
+			struct netlink_dump_control c = {
+				.module = family->module,
+				.dump = ops->dumpit,
+				.done = ops->done,
+			};
+
+			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+		}
+
+		return rc;
+	}
+
+	if (ops->doit == NULL)
+		return -EOPNOTSUPP;
+
+	if (family->maxattr && family->parallel_ops) {
+		attrbuf = kmalloc((family->maxattr+1) *
+					sizeof(struct nlattr *), GFP_KERNEL);
+		if (attrbuf == NULL)
+			return -ENOMEM;
+	} else
+		attrbuf = family->attrbuf;
+
+	if (attrbuf) {
+		err = nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
+				  ops->policy);
+		if (err < 0)
+			goto out;
+	}
+
+	info.snd_seq = nlh->nlmsg_seq;
+	info.snd_portid = NETLINK_CB(skb).portid;
+	info.nlhdr = nlh;
+	info.genlhdr = nlmsg_data(nlh);
+	info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
+	info.attrs = attrbuf;
+	info.dst_sk = skb->sk;
+	genl_info_net_set(&info, net);
+	memset(&info.user_ptr, 0, sizeof(info.user_ptr));
+
+	if (family->pre_doit) {
+		err = family->pre_doit(ops, skb, &info);
+		if (err)
+			goto out;
+	}
+
+	err = ops->doit(skb, &info);
+
+	if (family->post_doit)
+		family->post_doit(ops, skb, &info);
+
+out:
+	if (family->parallel_ops)
+		kfree(attrbuf);
+
+	return err;
+}
+
+static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+	struct genl_family *family;
+	int err;
+
+	family = genl_family_find_byid(nlh->nlmsg_type);
+	if (family == NULL)
+		return -ENOENT;
+
+	if (!family->parallel_ops)
+		genl_lock();
+
+	err = genl_family_rcv_msg(family, skb, nlh);
+
+	if (!family->parallel_ops)
+		genl_unlock();
+
+	return err;
+}
+
+static void genl_rcv(struct sk_buff *skb)
+{
+	down_read(&cb_lock);
+	netlink_rcv_skb(skb, &genl_rcv_msg);
+	up_read(&cb_lock);
+}
+
+/**************************************************************************
+ * Controller
+ **************************************************************************/
+
+static struct genl_family genl_ctrl = {
+	.id = GENL_ID_CTRL,
+	.name = "nlctrl",
+	.version = 0x2,
+	.maxattr = CTRL_ATTR_MAX,
+	.netnsok = true,
+};
+
+static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq,
+			  u32 flags, struct sk_buff *skb, u8 cmd)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
+	if (hdr == NULL)
+		return -1;
+
+	if (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))
+		goto nla_put_failure;
+
+	if (family->n_ops) {
+		struct nlattr *nla_ops;
+		int i;
+
+		nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);
+		if (nla_ops == NULL)
+			goto nla_put_failure;
+
+		for (i = 0; i < family->n_ops; i++) {
+			struct nlattr *nest;
+			const struct genl_ops *ops = &family->ops[i];
+			u32 op_flags = ops->flags;
+
+			if (ops->dumpit)
+				op_flags |= GENL_CMD_CAP_DUMP;
+			if (ops->doit)
+				op_flags |= GENL_CMD_CAP_DO;
+			if (ops->policy)
+				op_flags |= GENL_CMD_CAP_HASPOL;
+
+			nest = nla_nest_start(skb, i + 1);
+			if (nest == NULL)
+				goto nla_put_failure;
+
+			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||
+			    nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
+				goto nla_put_failure;
+
+			nla_nest_end(skb, nest);
+		}
+
+		nla_nest_end(skb, nla_ops);
+	}
+
+	if (family->n_mcgrps) {
+		struct nlattr *nla_grps;
+		int i;
+
+		nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+		if (nla_grps == NULL)
+			goto nla_put_failure;
+
+		for (i = 0; i < family->n_mcgrps; i++) {
+			struct nlattr *nest;
+			const struct genl_multicast_group *grp;
+
+			grp = &family->mcgrps[i];
+
+			nest = nla_nest_start(skb, i + 1);
+			if (nest == NULL)
+				goto nla_put_failure;
+
+			if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
+					family->mcgrp_offset + i) ||
+			    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
+					   grp->name))
+				goto nla_put_failure;
+
+			nla_nest_end(skb, nest);
+		}
+		nla_nest_end(skb, nla_grps);
+	}
+
+	genlmsg_end(skb, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+static int ctrl_fill_mcgrp_info(struct genl_family *family,
+				const struct genl_multicast_group *grp,
+				int grp_id, u32 portid, u32 seq, u32 flags,
+				struct sk_buff *skb, u8 cmd)
+{
+	void *hdr;
+	struct nlattr *nla_grps;
+	struct nlattr *nest;
+
+	hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
+	if (hdr == NULL)
+		return -1;
+
+	if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
+	    nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
+		goto nla_put_failure;
+
+	nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+	if (nla_grps == NULL)
+		goto nla_put_failure;
+
+	nest = nla_nest_start(skb, 1);
+	if (nest == NULL)
+		goto nla_put_failure;
+
+	if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
+	    nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
+			   grp->name))
+		goto nla_put_failure;
+
+	nla_nest_end(skb, nest);
+	nla_nest_end(skb, nla_grps);
+
+	genlmsg_end(skb, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
+{
+
+	int i, n = 0;
+	struct genl_family *rt;
+	struct net *net = sock_net(skb->sk);
+	int chains_to_skip = cb->args[0];
+	int fams_to_skip = cb->args[1];
+
+	for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
+		n = 0;
+		list_for_each_entry(rt, genl_family_chain(i), family_list) {
+			if (!rt->netnsok && !net_eq(net, &init_net))
+				continue;
+			if (++n < fams_to_skip)
+				continue;
+			if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
+					   cb->nlh->nlmsg_seq, NLM_F_MULTI,
+					   skb, CTRL_CMD_NEWFAMILY) < 0)
+				goto errout;
+		}
+
+		fams_to_skip = 0;
+	}
+
+errout:
+	cb->args[0] = i;
+	cb->args[1] = n;
+
+	return skb->len;
+}
+
+static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
+					     u32 portid, 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, portid, seq, 0, skb, cmd);
+	if (err < 0) {
+		nlmsg_free(skb);
+		return ERR_PTR(err);
+	}
+
+	return skb;
+}
+
+static struct sk_buff *
+ctrl_build_mcgrp_msg(struct genl_family *family,
+		     const struct genl_multicast_group *grp,
+		     int grp_id, u32 portid, 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_mcgrp_info(family, grp, grp_id, portid,
+				   seq, 0, skb, cmd);
+	if (err < 0) {
+		nlmsg_free(skb);
+		return ERR_PTR(err);
+	}
+
+	return skb;
+}
+
+static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
+	[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);
+		err = -ENOENT;
+	}
+
+	if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
+		char *name;
+
+		name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
+		res = genl_family_find_byname(name);
+#ifdef CONFIG_MODULES
+		if (res == NULL) {
+			genl_unlock();
+			up_read(&cb_lock);
+			request_module("net-pf-%d-proto-%d-family-%s",
+				       PF_NETLINK, NETLINK_GENERIC, name);
+			down_read(&cb_lock);
+			genl_lock();
+			res = genl_family_find_byname(name);
+		}
+#endif
+		err = -ENOENT;
+	}
+
+	if (res == NULL)
+		return err;
+
+	if (!res->netnsok && !net_eq(genl_info_net(info), &init_net)) {
+		/* family doesn't exist here */
+		return -ENOENT;
+	}
+
+	msg = ctrl_build_family_msg(res, info->snd_portid, info->snd_seq,
+				    CTRL_CMD_NEWFAMILY);
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
+
+	return genlmsg_reply(msg, info);
+}
+
+static int genl_ctrl_event(int event, struct genl_family *family,
+			   const struct genl_multicast_group *grp,
+			   int grp_id)
+{
+	struct sk_buff *msg;
+
+	/* genl is still initialising */
+	if (!init_net.genl_sock)
+		return 0;
+
+	switch (event) {
+	case CTRL_CMD_NEWFAMILY:
+	case CTRL_CMD_DELFAMILY:
+		WARN_ON(grp);
+		msg = ctrl_build_family_msg(family, 0, 0, event);
+		break;
+	case CTRL_CMD_NEWMCAST_GRP:
+	case CTRL_CMD_DELMCAST_GRP:
+		BUG_ON(!grp);
+		msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
+
+	if (!family->netnsok) {
+		genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0,
+					0, GFP_KERNEL);
+	} else {
+		rcu_read_lock();
+		genlmsg_multicast_allns(&genl_ctrl, msg, 0,
+					0, GFP_ATOMIC);
+		rcu_read_unlock();
+	}
+
+	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_multicast_group genl_ctrl_groups[] = {
+	{ .name = "notify", },
+};
+
+static int genl_bind(struct net *net, int group)
+{
+	int i, err = -ENOENT;
+
+	down_read(&cb_lock);
+	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
+		struct genl_family *f;
+
+		list_for_each_entry(f, genl_family_chain(i), family_list) {
+			if (group >= f->mcgrp_offset &&
+			    group < f->mcgrp_offset + f->n_mcgrps) {
+				int fam_grp = group - f->mcgrp_offset;
+
+				if (!f->netnsok && net != &init_net)
+					err = -ENOENT;
+				else if (f->mcast_bind)
+					err = f->mcast_bind(net, fam_grp);
+				else
+					err = 0;
+				break;
+			}
+		}
+	}
+	up_read(&cb_lock);
+
+	return err;
+}
+
+static void genl_unbind(struct net *net, int group)
+{
+	int i;
+
+	down_read(&cb_lock);
+	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
+		struct genl_family *f;
+
+		list_for_each_entry(f, genl_family_chain(i), family_list) {
+			if (group >= f->mcgrp_offset &&
+			    group < f->mcgrp_offset + f->n_mcgrps) {
+				int fam_grp = group - f->mcgrp_offset;
+
+				if (f->mcast_unbind)
+					f->mcast_unbind(net, fam_grp);
+				break;
+			}
+		}
+	}
+	up_read(&cb_lock);
+}
+
+static int __net_init genl_pernet_init(struct net *net)
+{
+	struct netlink_kernel_cfg cfg = {
+		.input		= genl_rcv,
+		.flags		= NL_CFG_F_NONROOT_RECV,
+		.bind		= genl_bind,
+		.unbind		= genl_unbind,
+	};
+
+	/* we'll bump the group number right afterwards */
+	net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, &cfg);
+
+	if (!net->genl_sock && net_eq(net, &init_net))
+		panic("GENL: Cannot initialize generic netlink\n");
+
+	if (!net->genl_sock)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void __net_exit genl_pernet_exit(struct net *net)
+{
+	netlink_kernel_release(net->genl_sock);
+	net->genl_sock = NULL;
+}
+
+static struct pernet_operations genl_pernet_ops = {
+	.init = genl_pernet_init,
+	.exit = genl_pernet_exit,
+};
+
+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_with_ops_groups(&genl_ctrl, genl_ctrl_ops,
+						   genl_ctrl_groups);
+	if (err < 0)
+		goto problem;
+
+	err = register_pernet_subsys(&genl_pernet_ops);
+	if (err)
+		goto problem;
+
+	return 0;
+
+problem:
+	panic("GENL: Cannot register controller: %d\n", err);
+}
+
+subsys_initcall(genl_init);
+
+static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
+			 gfp_t flags)
+{
+	struct sk_buff *tmp;
+	struct net *net, *prev = NULL;
+	int err;
+
+	for_each_net_rcu(net) {
+		if (prev) {
+			tmp = skb_clone(skb, flags);
+			if (!tmp) {
+				err = -ENOMEM;
+				goto error;
+			}
+			err = nlmsg_multicast(prev->genl_sock, tmp,
+					      portid, group, flags);
+			if (err)
+				goto error;
+		}
+
+		prev = net;
+	}
+
+	return nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
+ error:
+	kfree_skb(skb);
+	return err;
+}
+
+int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb,
+			    u32 portid, unsigned int group, gfp_t flags)
+{
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
+		return -EINVAL;
+	group = family->mcgrp_offset + group;
+	return genlmsg_mcast(skb, portid, group, flags);
+}
+EXPORT_SYMBOL(genlmsg_multicast_allns);
+
+void genl_notify(struct genl_family *family,
+		 struct sk_buff *skb, struct net *net, u32 portid, u32 group,
+		 struct nlmsghdr *nlh, gfp_t flags)
+{
+	struct sock *sk = net->genl_sock;
+	int report = 0;
+
+	if (nlh)
+		report = nlmsg_report(nlh);
+
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
+		return;
+	group = family->mcgrp_offset + group;
+	nlmsg_notify(sk, skb, portid, group, report, flags);
+}
+EXPORT_SYMBOL(genl_notify);