Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1565 insertions, 0 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
new file mode 100644
index 000000000..505d3b910
--- /dev/null
+++ b/net/netlink/genetlink.c
@@ -0,0 +1,1565 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 <linux/idr.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);
+
+static void genl_lock_all(void)
+{
+	down_write(&cb_lock);
+	genl_lock();
+}
+
+static void genl_unlock_all(void)
+{
+	genl_unlock();
+	up_write(&cb_lock);
+}
+
+static DEFINE_IDR(genl_fam_idr);
+
+/*
+ * 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;
+
+/* We need the last attribute with non-zero ID therefore a 2-entry array */
+static struct nla_policy genl_policy_reject_all[] = {
+	{ .type = NLA_REJECT },
+	{ .type = NLA_REJECT },
+};
+
+static int genl_ctrl_event(int event, const struct genl_family *family,
+			   const struct genl_multicast_group *grp,
+			   int grp_id);
+
+static void
+genl_op_fill_in_reject_policy(const struct genl_family *family,
+			      struct genl_ops *op)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(genl_policy_reject_all) - 1 != 1);
+
+	if (op->policy || op->cmd < family->resv_start_op)
+		return;
+
+	op->policy = genl_policy_reject_all;
+	op->maxattr = 1;
+}
+
+static const struct genl_family *genl_family_find_byid(unsigned int id)
+{
+	return idr_find(&genl_fam_idr, id);
+}
+
+static const struct genl_family *genl_family_find_byname(char *name)
+{
+	const struct genl_family *family;
+	unsigned int id;
+
+	idr_for_each_entry(&genl_fam_idr, family, id)
+		if (strcmp(family->name, name) == 0)
+			return family;
+
+	return NULL;
+}
+
+static int genl_get_cmd_cnt(const struct genl_family *family)
+{
+	return family->n_ops + family->n_small_ops;
+}
+
+static void genl_op_from_full(const struct genl_family *family,
+			      unsigned int i, struct genl_ops *op)
+{
+	*op = family->ops[i];
+
+	if (!op->maxattr)
+		op->maxattr = family->maxattr;
+	if (!op->policy)
+		op->policy = family->policy;
+
+	genl_op_fill_in_reject_policy(family, op);
+}
+
+static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
+			     struct genl_ops *op)
+{
+	int i;
+
+	for (i = 0; i < family->n_ops; i++)
+		if (family->ops[i].cmd == cmd) {
+			genl_op_from_full(family, i, op);
+			return 0;
+		}
+
+	return -ENOENT;
+}
+
+static void genl_op_from_small(const struct genl_family *family,
+			       unsigned int i, struct genl_ops *op)
+{
+	memset(op, 0, sizeof(*op));
+	op->doit	= family->small_ops[i].doit;
+	op->dumpit	= family->small_ops[i].dumpit;
+	op->cmd		= family->small_ops[i].cmd;
+	op->internal_flags = family->small_ops[i].internal_flags;
+	op->flags	= family->small_ops[i].flags;
+	op->validate	= family->small_ops[i].validate;
+
+	op->maxattr = family->maxattr;
+	op->policy = family->policy;
+
+	genl_op_fill_in_reject_policy(family, op);
+}
+
+static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
+			      struct genl_ops *op)
+{
+	int i;
+
+	for (i = 0; i < family->n_small_ops; i++)
+		if (family->small_ops[i].cmd == cmd) {
+			genl_op_from_small(family, i, op);
+			return 0;
+		}
+
+	return -ENOENT;
+}
+
+static int genl_get_cmd(u32 cmd, const struct genl_family *family,
+			struct genl_ops *op)
+{
+	if (!genl_get_cmd_full(cmd, family, op))
+		return 0;
+	return genl_get_cmd_small(cmd, family, op);
+}
+
+static void genl_get_cmd_by_index(unsigned int i,
+				  const struct genl_family *family,
+				  struct genl_ops *op)
+{
+	if (i < family->n_ops)
+		genl_op_from_full(family, i, op);
+	else if (i < family->n_ops + family->n_small_ops)
+		genl_op_from_small(family, i - family->n_ops, op);
+	else
+		WARN_ON_ONCE(1);
+}
+
+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 + n_groups > 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 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(const 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)
+{
+	int i, j;
+
+	if (WARN_ON(family->n_ops && !family->ops) ||
+	    WARN_ON(family->n_small_ops && !family->small_ops))
+		return -EINVAL;
+
+	for (i = 0; i < genl_get_cmd_cnt(family); i++) {
+		struct genl_ops op;
+
+		genl_get_cmd_by_index(i, family, &op);
+		if (op.dumpit == NULL && op.doit == NULL)
+			return -EINVAL;
+		if (WARN_ON(op.cmd >= family->resv_start_op && op.validate))
+			return -EINVAL;
+		for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
+			struct genl_ops op2;
+
+			genl_get_cmd_by_index(j, family, &op2);
+			if (op.cmd == op2.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's ops, multicast groups and module pointer must already
+ * be assigned.
+ *
+ * Return 0 on success or a negative error code.
+ */
+int genl_register_family(struct genl_family *family)
+{
+	int err, i;
+	int start = GENL_START_ALLOC, end = GENL_MAX_ID;
+
+	err = genl_validate_ops(family);
+	if (err)
+		return err;
+
+	genl_lock_all();
+
+	if (genl_family_find_byname(family->name)) {
+		err = -EEXIST;
+		goto errout_locked;
+	}
+
+	/*
+	 * Sadly, a few cases need to be special-cased
+	 * due to them having previously abused the API
+	 * and having used their family ID also as their
+	 * multicast group ID, so we use reserved IDs
+	 * for both to be sure we can do that mapping.
+	 */
+	if (family == &genl_ctrl) {
+		/* and this needs to be special for initial family lookups */
+		start = end = GENL_ID_CTRL;
+	} else if (strcmp(family->name, "pmcraid") == 0) {
+		start = end = GENL_ID_PMCRAID;
+	} else if (strcmp(family->name, "VFS_DQUOT") == 0) {
+		start = end = GENL_ID_VFS_DQUOT;
+	}
+
+	family->id = idr_alloc_cyclic(&genl_fam_idr, family,
+				      start, end + 1, GFP_KERNEL);
+	if (family->id < 0) {
+		err = family->id;
+		goto errout_locked;
+	}
+
+	err = genl_validate_assign_mc_groups(family);
+	if (err)
+		goto errout_remove;
+
+	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_remove:
+	idr_remove(&genl_fam_idr, family->id);
+errout_locked:
+	genl_unlock_all();
+	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(const struct genl_family *family)
+{
+	genl_lock_all();
+
+	if (!genl_family_find_byid(family->id)) {
+		genl_unlock_all();
+		return -ENOENT;
+	}
+
+	genl_unregister_mc_groups(family);
+
+	idr_remove(&genl_fam_idr, family->id);
+
+	up_write(&cb_lock);
+	wait_event(genl_sk_destructing_waitq,
+		   atomic_read(&genl_sk_destructing_cnt) == 0);
+	genl_unlock();
+
+	genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
+
+	return 0;
+}
+EXPORT_SYMBOL(genl_unregister_family);
+
+/**
+ * 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,
+		  const 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 struct genl_dumpit_info *genl_dumpit_info_alloc(void)
+{
+	return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
+}
+
+static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
+{
+	kfree(info);
+}
+
+static struct nlattr **
+genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
+				struct nlmsghdr *nlh,
+				struct netlink_ext_ack *extack,
+				const struct genl_ops *ops,
+				int hdrlen,
+				enum genl_validate_flags no_strict_flag)
+{
+	enum netlink_validation validate = ops->validate & no_strict_flag ?
+					   NL_VALIDATE_LIBERAL :
+					   NL_VALIDATE_STRICT;
+	struct nlattr **attrbuf;
+	int err;
+
+	if (!ops->maxattr)
+		return NULL;
+
+	attrbuf = kmalloc_array(ops->maxattr + 1,
+				sizeof(struct nlattr *), GFP_KERNEL);
+	if (!attrbuf)
+		return ERR_PTR(-ENOMEM);
+
+	err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
+			    validate, extack);
+	if (err) {
+		kfree(attrbuf);
+		return ERR_PTR(err);
+	}
+	return attrbuf;
+}
+
+static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
+{
+	kfree(attrbuf);
+}
+
+struct genl_start_context {
+	const struct genl_family *family;
+	struct nlmsghdr *nlh;
+	struct netlink_ext_ack *extack;
+	const struct genl_ops *ops;
+	int hdrlen;
+};
+
+static int genl_start(struct netlink_callback *cb)
+{
+	struct genl_start_context *ctx = cb->data;
+	const struct genl_ops *ops = ctx->ops;
+	struct genl_dumpit_info *info;
+	struct nlattr **attrs = NULL;
+	int rc = 0;
+
+	if (ops->validate & GENL_DONT_VALIDATE_DUMP)
+		goto no_attrs;
+
+	if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
+		return -EINVAL;
+
+	attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
+						ops, ctx->hdrlen,
+						GENL_DONT_VALIDATE_DUMP_STRICT);
+	if (IS_ERR(attrs))
+		return PTR_ERR(attrs);
+
+no_attrs:
+	info = genl_dumpit_info_alloc();
+	if (!info) {
+		genl_family_rcv_msg_attrs_free(attrs);
+		return -ENOMEM;
+	}
+	info->family = ctx->family;
+	info->op = *ops;
+	info->attrs = attrs;
+
+	cb->data = info;
+	if (ops->start) {
+		if (!ctx->family->parallel_ops)
+			genl_lock();
+		rc = ops->start(cb);
+		if (!ctx->family->parallel_ops)
+			genl_unlock();
+	}
+
+	if (rc) {
+		genl_family_rcv_msg_attrs_free(info->attrs);
+		genl_dumpit_info_free(info);
+		cb->data = NULL;
+	}
+	return rc;
+}
+
+static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
+	int rc;
+
+	genl_lock();
+	rc = ops->dumpit(skb, cb);
+	genl_unlock();
+	return rc;
+}
+
+static int genl_lock_done(struct netlink_callback *cb)
+{
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	const struct genl_ops *ops = &info->op;
+	int rc = 0;
+
+	if (ops->done) {
+		genl_lock();
+		rc = ops->done(cb);
+		genl_unlock();
+	}
+	genl_family_rcv_msg_attrs_free(info->attrs);
+	genl_dumpit_info_free(info);
+	return rc;
+}
+
+static int genl_parallel_done(struct netlink_callback *cb)
+{
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	const struct genl_ops *ops = &info->op;
+	int rc = 0;
+
+	if (ops->done)
+		rc = ops->done(cb);
+	genl_family_rcv_msg_attrs_free(info->attrs);
+	genl_dumpit_info_free(info);
+	return rc;
+}
+
+static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
+				      struct sk_buff *skb,
+				      struct nlmsghdr *nlh,
+				      struct netlink_ext_ack *extack,
+				      const struct genl_ops *ops,
+				      int hdrlen, struct net *net)
+{
+	struct genl_start_context ctx;
+	int err;
+
+	if (!ops->dumpit)
+		return -EOPNOTSUPP;
+
+	ctx.family = family;
+	ctx.nlh = nlh;
+	ctx.extack = extack;
+	ctx.ops = ops;
+	ctx.hdrlen = hdrlen;
+
+	if (!family->parallel_ops) {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			.data = &ctx,
+			.start = genl_start,
+			.dump = genl_lock_dumpit,
+			.done = genl_lock_done,
+		};
+
+		genl_unlock();
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+		genl_lock();
+	} else {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			.data = &ctx,
+			.start = genl_start,
+			.dump = ops->dumpit,
+			.done = genl_parallel_done,
+		};
+
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+	}
+
+	return err;
+}
+
+static int genl_family_rcv_msg_doit(const struct genl_family *family,
+				    struct sk_buff *skb,
+				    struct nlmsghdr *nlh,
+				    struct netlink_ext_ack *extack,
+				    const struct genl_ops *ops,
+				    int hdrlen, struct net *net)
+{
+	struct nlattr **attrbuf;
+	struct genl_info info;
+	int err;
+
+	if (!ops->doit)
+		return -EOPNOTSUPP;
+
+	attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
+						  ops, hdrlen,
+						  GENL_DONT_VALIDATE_STRICT);
+	if (IS_ERR(attrbuf))
+		return PTR_ERR(attrbuf);
+
+	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.extack = extack;
+	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:
+	genl_family_rcv_msg_attrs_free(attrbuf);
+
+	return err;
+}
+
+static int genl_header_check(const struct genl_family *family,
+			     struct nlmsghdr *nlh, struct genlmsghdr *hdr,
+			     struct netlink_ext_ack *extack)
+{
+	u16 flags;
+
+	/* Only for commands added after we started validating */
+	if (hdr->cmd < family->resv_start_op)
+		return 0;
+
+	if (hdr->reserved) {
+		NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0");
+		return -EINVAL;
+	}
+
+	/* Old netlink flags have pretty loose semantics, allow only the flags
+	 * consumed by the core where we can enforce the meaning.
+	 */
+	flags = nlh->nlmsg_flags;
+	if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */
+		flags &= ~NLM_F_DUMP;
+	if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) {
+		NL_SET_ERR_MSG(extack,
+			       "ambiguous or reserved bits set in nlmsg_flags");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int genl_family_rcv_msg(const struct genl_family *family,
+			       struct sk_buff *skb,
+			       struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct genlmsghdr *hdr = nlmsg_data(nlh);
+	struct genl_ops op;
+	int hdrlen;
+
+	/* 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;
+
+	if (genl_header_check(family, nlh, hdr, extack))
+		return -EINVAL;
+
+	if (genl_get_cmd(hdr->cmd, family, &op))
+		return -EOPNOTSUPP;
+
+	if ((op.flags & GENL_ADMIN_PERM) &&
+	    !netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((op.flags & GENL_UNS_ADMIN_PERM) &&
+	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
+		return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
+						  &op, hdrlen, net);
+	else
+		return genl_family_rcv_msg_doit(family, skb, nlh, extack,
+						&op, hdrlen, net);
+}
+
+static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
+			struct netlink_ext_ack *extack)
+{
+	const 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, extack);
+
+	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;
+
+static int ctrl_fill_info(const 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 (genl_get_cmd_cnt(family)) {
+		struct nlattr *nla_ops;
+		int i;
+
+		nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
+		if (nla_ops == NULL)
+			goto nla_put_failure;
+
+		for (i = 0; i < genl_get_cmd_cnt(family); i++) {
+			struct nlattr *nest;
+			struct genl_ops op;
+			u32 op_flags;
+
+			genl_get_cmd_by_index(i, family, &op);
+			op_flags = op.flags;
+			if (op.dumpit)
+				op_flags |= GENL_CMD_CAP_DUMP;
+			if (op.doit)
+				op_flags |= GENL_CMD_CAP_DO;
+			if (op.policy)
+				op_flags |= GENL_CMD_CAP_HASPOL;
+
+			nest = nla_nest_start_noflag(skb, i + 1);
+			if (nest == NULL)
+				goto nla_put_failure;
+
+			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.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_noflag(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_noflag(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(const 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_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
+	if (nla_grps == NULL)
+		goto nla_put_failure;
+
+	nest = nla_nest_start_noflag(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 n = 0;
+	struct genl_family *rt;
+	struct net *net = sock_net(skb->sk);
+	int fams_to_skip = cb->args[0];
+	unsigned int id;
+
+	idr_for_each_entry(&genl_fam_idr, rt, id) {
+		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) {
+			n--;
+			break;
+		}
+	}
+
+	cb->args[0] = n;
+	return skb->len;
+}
+
+static struct sk_buff *ctrl_build_family_msg(const 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(const 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_family[] = {
+	[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;
+	const 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, const 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;
+}
+
+struct ctrl_dump_policy_ctx {
+	struct netlink_policy_dump_state *state;
+	const struct genl_family *rt;
+	unsigned int opidx;
+	u32 op;
+	u16 fam_id;
+	u8 policies:1,
+	   single_op:1;
+};
+
+static const struct nla_policy ctrl_policy_policy[] = {
+	[CTRL_ATTR_FAMILY_ID]	= { .type = NLA_U16 },
+	[CTRL_ATTR_FAMILY_NAME]	= { .type = NLA_NUL_STRING,
+				    .len = GENL_NAMSIZ - 1 },
+	[CTRL_ATTR_OP]		= { .type = NLA_U32 },
+};
+
+static int ctrl_dumppolicy_start(struct netlink_callback *cb)
+{
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+	struct nlattr **tb = info->attrs;
+	const struct genl_family *rt;
+	struct genl_ops op;
+	int err, i;
+
+	BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx));
+
+	if (!tb[CTRL_ATTR_FAMILY_ID] && !tb[CTRL_ATTR_FAMILY_NAME])
+		return -EINVAL;
+
+	if (tb[CTRL_ATTR_FAMILY_ID]) {
+		ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]);
+	} else {
+		rt = genl_family_find_byname(
+			nla_data(tb[CTRL_ATTR_FAMILY_NAME]));
+		if (!rt)
+			return -ENOENT;
+		ctx->fam_id = rt->id;
+	}
+
+	rt = genl_family_find_byid(ctx->fam_id);
+	if (!rt)
+		return -ENOENT;
+
+	ctx->rt = rt;
+
+	if (tb[CTRL_ATTR_OP]) {
+		ctx->single_op = true;
+		ctx->op = nla_get_u32(tb[CTRL_ATTR_OP]);
+
+		err = genl_get_cmd(ctx->op, rt, &op);
+		if (err) {
+			NL_SET_BAD_ATTR(cb->extack, tb[CTRL_ATTR_OP]);
+			return err;
+		}
+
+		if (!op.policy)
+			return -ENODATA;
+
+		return netlink_policy_dump_add_policy(&ctx->state, op.policy,
+						      op.maxattr);
+	}
+
+	for (i = 0; i < genl_get_cmd_cnt(rt); i++) {
+		genl_get_cmd_by_index(i, rt, &op);
+
+		if (op.policy) {
+			err = netlink_policy_dump_add_policy(&ctx->state,
+							     op.policy,
+							     op.maxattr);
+			if (err)
+				goto err_free_state;
+		}
+	}
+
+	if (!ctx->state)
+		return -ENODATA;
+	return 0;
+
+err_free_state:
+	netlink_policy_dump_free(ctx->state);
+	return err;
+}
+
+static void *ctrl_dumppolicy_prep(struct sk_buff *skb,
+				  struct netlink_callback *cb)
+{
+	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+	void *hdr;
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+			  cb->nlh->nlmsg_seq, &genl_ctrl,
+			  NLM_F_MULTI, CTRL_CMD_GETPOLICY);
+	if (!hdr)
+		return NULL;
+
+	if (nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, ctx->fam_id))
+		return NULL;
+
+	return hdr;
+}
+
+static int ctrl_dumppolicy_put_op(struct sk_buff *skb,
+				  struct netlink_callback *cb,
+			          struct genl_ops *op)
+{
+	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+	struct nlattr *nest_pol, *nest_op;
+	void *hdr;
+	int idx;
+
+	/* skip if we have nothing to show */
+	if (!op->policy)
+		return 0;
+	if (!op->doit &&
+	    (!op->dumpit || op->validate & GENL_DONT_VALIDATE_DUMP))
+		return 0;
+
+	hdr = ctrl_dumppolicy_prep(skb, cb);
+	if (!hdr)
+		return -ENOBUFS;
+
+	nest_pol = nla_nest_start(skb, CTRL_ATTR_OP_POLICY);
+	if (!nest_pol)
+		goto err;
+
+	nest_op = nla_nest_start(skb, op->cmd);
+	if (!nest_op)
+		goto err;
+
+	/* for now both do/dump are always the same */
+	idx = netlink_policy_dump_get_policy_idx(ctx->state,
+						 op->policy,
+						 op->maxattr);
+
+	if (op->doit && nla_put_u32(skb, CTRL_ATTR_POLICY_DO, idx))
+		goto err;
+
+	if (op->dumpit && !(op->validate & GENL_DONT_VALIDATE_DUMP) &&
+	    nla_put_u32(skb, CTRL_ATTR_POLICY_DUMP, idx))
+		goto err;
+
+	nla_nest_end(skb, nest_op);
+	nla_nest_end(skb, nest_pol);
+	genlmsg_end(skb, hdr);
+
+	return 0;
+err:
+	genlmsg_cancel(skb, hdr);
+	return -ENOBUFS;
+}
+
+static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+	void *hdr;
+
+	if (!ctx->policies) {
+		while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
+			struct genl_ops op;
+
+			if (ctx->single_op) {
+				int err;
+
+				err = genl_get_cmd(ctx->op, ctx->rt, &op);
+				if (WARN_ON(err))
+					return skb->len;
+
+				/* break out of the loop after this one */
+				ctx->opidx = genl_get_cmd_cnt(ctx->rt);
+			} else {
+				genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
+			}
+
+			if (ctrl_dumppolicy_put_op(skb, cb, &op))
+				return skb->len;
+
+			ctx->opidx++;
+		}
+
+		/* completed with the per-op policy index list */
+		ctx->policies = true;
+	}
+
+	while (netlink_policy_dump_loop(ctx->state)) {
+		struct nlattr *nest;
+
+		hdr = ctrl_dumppolicy_prep(skb, cb);
+		if (!hdr)
+			goto nla_put_failure;
+
+		nest = nla_nest_start(skb, CTRL_ATTR_POLICY);
+		if (!nest)
+			goto nla_put_failure;
+
+		if (netlink_policy_dump_write(skb, ctx->state))
+			goto nla_put_failure;
+
+		nla_nest_end(skb, nest);
+
+		genlmsg_end(skb, hdr);
+	}
+
+	return skb->len;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+	return skb->len;
+}
+
+static int ctrl_dumppolicy_done(struct netlink_callback *cb)
+{
+	struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
+
+	netlink_policy_dump_free(ctx->state);
+	return 0;
+}
+
+static const struct genl_ops genl_ctrl_ops[] = {
+	{
+		.cmd		= CTRL_CMD_GETFAMILY,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.policy		= ctrl_policy_family,
+		.maxattr	= ARRAY_SIZE(ctrl_policy_family) - 1,
+		.doit		= ctrl_getfamily,
+		.dumpit		= ctrl_dumpfamily,
+	},
+	{
+		.cmd		= CTRL_CMD_GETPOLICY,
+		.policy		= ctrl_policy_policy,
+		.maxattr	= ARRAY_SIZE(ctrl_policy_policy) - 1,
+		.start		= ctrl_dumppolicy_start,
+		.dumpit		= ctrl_dumppolicy,
+		.done		= ctrl_dumppolicy_done,
+	},
+};
+
+static const struct genl_multicast_group genl_ctrl_groups[] = {
+	{ .name = "notify", },
+};
+
+static struct genl_family genl_ctrl __ro_after_init = {
+	.module = THIS_MODULE,
+	.ops = genl_ctrl_ops,
+	.n_ops = ARRAY_SIZE(genl_ctrl_ops),
+	.resv_start_op = CTRL_CMD_GETPOLICY + 1,
+	.mcgrps = genl_ctrl_groups,
+	.n_mcgrps = ARRAY_SIZE(genl_ctrl_groups),
+	.id = GENL_ID_CTRL,
+	.name = "nlctrl",
+	.version = 0x2,
+	.netnsok = true,
+};
+
+static int genl_bind(struct net *net, int group)
+{
+	const struct genl_family *family;
+	unsigned int id;
+	int ret = 0;
+
+	down_read(&cb_lock);
+
+	idr_for_each_entry(&genl_fam_idr, family, id) {
+		const struct genl_multicast_group *grp;
+		int i;
+
+		if (family->n_mcgrps == 0)
+			continue;
+
+		i = group - family->mcgrp_offset;
+		if (i < 0 || i >= family->n_mcgrps)
+			continue;
+
+		grp = &family->mcgrps[i];
+		if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
+		    !ns_capable(net->user_ns, CAP_NET_ADMIN))
+			ret = -EPERM;
+		if (grp->cap_sys_admin &&
+		    !ns_capable(net->user_ns, CAP_SYS_ADMIN))
+			ret = -EPERM;
+
+		break;
+	}
+
+	up_read(&cb_lock);
+	return ret;
+}
+
+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,
+	};
+
+	/* 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 err;
+
+	err = genl_register_family(&genl_ctrl);
+	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);
+}
+
+core_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;
+	bool delivered = false;
+	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)
+				delivered = true;
+			else if (err != -ESRCH)
+				goto error;
+		}
+
+		prev = net;
+	}
+
+	err = nlmsg_multicast(prev->genl_sock, skb, portid, group, flags);
+	if (!err)
+		delivered = true;
+	else if (err != -ESRCH)
+		return err;
+	return delivered ? 0 : -ESRCH;
+ error:
+	kfree_skb(skb);
+	return err;
+}
+
+int genlmsg_multicast_allns(const 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(const struct genl_family *family, struct sk_buff *skb,
+		 struct genl_info *info, u32 group, gfp_t flags)
+{
+	struct net *net = genl_info_net(info);
+	struct sock *sk = net->genl_sock;
+
+	if (WARN_ON_ONCE(group >= family->n_mcgrps))
+		return;
+
+	group = family->mcgrp_offset + group;
+	nlmsg_notify(sk, skb, info->snd_portid, group,
+		     nlmsg_report(info->nlhdr), flags);
+}
+EXPORT_SYMBOL(genl_notify);