Commit 0b588afd authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

genetlink: add small version of ops 



We want to add maxattr and policy back to genl_ops, to enable
dumping per command policy to user space. This, however, would
cause bloat for all the families with global policies. Introduce
smaller version of ops (half the size of genl_ops). Translate
these smaller ops into a full blown struct before use in the
core.

v1:
 - use struct assignment
 - put a full copy of the op in struct genl_dumpit_info
 - s/light/small/

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e5086736

drivers/thermal/thermal_netlink.c

+1 −1
Original line number Diff line number Diff line
@@ -545,7 +545,7 @@ static int thermal_genl_cmd_dumpit(struct sk_buff *skb, 
{

	struct param p = { .msg = skb };

	const struct genl_dumpit_info *info = genl_dumpit_info(cb);

	int cmd = info->ops->cmd;

	int cmd = info->op.cmd;

	int ret;

	void *hdr;

include/net/genetlink.h

+39 −14
Original line number Diff line number Diff line
@@ -41,6 +41,8 @@ struct genl_info; 
 *	(private)

 * @ops: the operations supported by this family

 * @n_ops: number of operations supported by this family

 * @small_ops: the small-struct operations supported by this family

 * @n_small_ops: number of small-struct operations supported by this family

 */

struct genl_family {

	int			id;		/* private */
@@ -52,6 +54,7 @@ struct genl_family { 
	u8			netnsok:1;

	u8			parallel_ops:1;

	u8			n_ops;

	u8			n_small_ops;

	u8			n_mcgrps;

	const struct nla_policy *policy;

	int			(*pre_doit)(const struct genl_ops *ops,
@@ -61,6 +64,7 @@ struct genl_family { 
					     struct sk_buff *skb,

					     struct genl_info *info);

	const struct genl_ops *	ops;

	const struct genl_small_ops *small_ops;

	const struct genl_multicast_group *mcgrps;

	struct module		*module;

};
@@ -108,23 +112,26 @@ enum genl_validate_flags { 
};



/**

 * struct genl_info - info that is available during dumpit op call

 * @family: generic netlink family - for internal genl code usage

 * @ops: generic netlink ops - for internal genl code usage

 * @attrs: netlink attributes

 * struct genl_small_ops - generic netlink operations (small version)

 * @cmd: command identifier

 * @internal_flags: flags used by the family

 * @flags: flags

 * @validate: validation flags from enum genl_validate_flags

 * @doit: standard command callback

 * @dumpit: callback for dumpers

 *

 * This is a cut-down version of struct genl_ops for users who don't need

 * most of the ancillary infra and want to save space.

 */

struct genl_dumpit_info {

	const struct genl_family *family;

	const struct genl_ops *ops;

	struct nlattr **attrs;

struct genl_small_ops {

	int	(*doit)(struct sk_buff *skb, struct genl_info *info);

	int	(*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);

	u8	cmd;

	u8	internal_flags;

	u8	flags;

	u8	validate;

};



static inline const struct genl_dumpit_info *

genl_dumpit_info(struct netlink_callback *cb)

{

	return cb->data;

}



/**

 * struct genl_ops - generic netlink operations

 * @cmd: command identifier
@@ -148,6 +155,24 @@ struct genl_ops { 
	u8			validate;

};



/**

 * struct genl_info - info that is available during dumpit op call

 * @family: generic netlink family - for internal genl code usage

 * @ops: generic netlink ops - for internal genl code usage

 * @attrs: netlink attributes

 */

struct genl_dumpit_info {

	const struct genl_family *family;

	struct genl_ops op;

	struct nlattr **attrs;

};



static inline const struct genl_dumpit_info *

genl_dumpit_info(struct netlink_callback *cb)

{

	return cb->data;

}



int genl_register_family(struct genl_family *family);

int genl_unregister_family(const struct genl_family *family);

void genl_notify(const struct genl_family *family, struct sk_buff *skb,

net/netlink/genetlink.c

+95 −32
Original line number Diff line number Diff line
@@ -107,16 +107,75 @@ static const struct genl_family *genl_family_find_byname(char *name) 
	return NULL;

}



static const struct genl_ops *genl_get_cmd(u8 cmd,

					   const struct genl_family *family)

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];

}



static int genl_get_cmd_full(u8 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)

			return &family->ops[i];

		if (family->ops[i].cmd == cmd) {

			genl_op_from_full(family, i, op);

			return 0;

		}



	return NULL;

	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;

}



static int genl_get_cmd_small(u8 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(u8 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)
@@ -286,23 +345,26 @@ static void genl_unregister_mc_groups(const struct genl_family *family) 


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))

	if (WARN_ON(family->n_ops && !family->ops) ||

	    WARN_ON(family->n_small_ops && !family->small_ops))

		return -EINVAL;



	if (!n_ops)

		return 0;

	for (i = 0; i < genl_get_cmd_cnt(family); i++) {

		struct genl_ops op;



	for (i = 0; i < n_ops; i++) {

		if (ops[i].dumpit == NULL && ops[i].doit == NULL)

		genl_get_cmd_by_index(i, family, &op);

		if (op.dumpit == NULL && op.doit == NULL)

			return -EINVAL;

		for (j = i + 1; j < n_ops; j++)

			if (ops[i].cmd == ops[j].cmd)

		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;

}
@@ -524,7 +586,7 @@ static int genl_start(struct netlink_callback *cb) 
		return -ENOMEM;

	}

	info->family = ctx->family;

	info->ops = ops;

	info->op = *ops;

	info->attrs = attrs;



	cb->data = info;
@@ -546,7 +608,7 @@ static int genl_start(struct netlink_callback *cb) 


static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)

{

	const struct genl_ops *ops = genl_dumpit_info(cb)->ops;

	const struct genl_ops *ops = &genl_dumpit_info(cb)->op;

	int rc;



	genl_lock();
@@ -558,7 +620,7 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb) 
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->ops;

	const struct genl_ops *ops = &info->op;

	int rc = 0;



	if (ops->done) {
@@ -574,7 +636,7 @@ static int genl_lock_done(struct netlink_callback *cb) 
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->ops;

	const struct genl_ops *ops = &info->op;

	int rc = 0;



	if (ops->done)
@@ -682,9 +744,9 @@ static int genl_family_rcv_msg(const struct genl_family *family, 
			       struct nlmsghdr *nlh,

			       struct netlink_ext_ack *extack)

{

	const struct genl_ops *ops;

	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 */
@@ -695,24 +757,23 @@ static int genl_family_rcv_msg(const struct genl_family *family, 
	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))

		return -EINVAL;



	ops = genl_get_cmd(hdr->cmd, family);

	if (ops == NULL)

	if (genl_get_cmd(hdr->cmd, family, &op))

		return -EOPNOTSUPP;



	if ((ops->flags & GENL_ADMIN_PERM) &&

	if ((op.flags & GENL_ADMIN_PERM) &&

	    !netlink_capable(skb, CAP_NET_ADMIN))

		return -EPERM;



	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&

	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,

						  ops, hdrlen, net);

						  &op, hdrlen, net);

	else

		return genl_family_rcv_msg_doit(family, skb, nlh, extack,

						ops, hdrlen, net);

						&op, hdrlen, net);

}



static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -765,7 +826,7 @@ static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 
	    nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))

		goto nla_put_failure;



	if (family->n_ops) {

	if (genl_get_cmd_cnt(family)) {

		struct nlattr *nla_ops;

		int i;
@@ -773,14 +834,16 @@ static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 
		if (nla_ops == NULL)

			goto nla_put_failure;



		for (i = 0; i < family->n_ops; i++) {

		for (i = 0; i < genl_get_cmd_cnt(family); i++) {

			struct nlattr *nest;

			const struct genl_ops *ops = &family->ops[i];

			u32 op_flags = ops->flags;

			struct genl_ops op;

			u32 op_flags;



			if (ops->dumpit)

			genl_get_cmd_by_index(i, family, &op);

			op_flags = op.flags;

			if (op.dumpit)

				op_flags |= GENL_CMD_CAP_DUMP;

			if (ops->doit)

			if (op.doit)

				op_flags |= GENL_CMD_CAP_DO;

			if (family->policy)

				op_flags |= GENL_CMD_CAP_HASPOL;
@@ -789,7 +852,7 @@ static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq, 
			if (nest == NULL)

				goto nla_put_failure;



			if (nla_put_u32(skb, CTRL_ATTR_OP_ID, ops->cmd) ||

			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;