1#include <linux/kernel.h>
2#include <net/netlink.h>
3#include <linux/drbd_genl_api.h>
4#include "drbd_nla.h"
5
6static int drbd_nla_check_mandatory(int maxtype, struct nlattr *nla)
7{
8	struct nlattr *head = nla_data(nla);
9	int len = nla_len(nla);
10	int rem;
11
12	/*
13	 * validate_nla (called from nla_parse_nested) ignores attributes
14	 * beyond maxtype, and does not understand the DRBD_GENLA_F_MANDATORY flag.
15	 * In order to have it validate attributes with the DRBD_GENLA_F_MANDATORY
16	 * flag set also, check and remove that flag before calling
17	 * nla_parse_nested.
18	 */
19
20	nla_for_each_attr(nla, head, len, rem) {
21		if (nla->nla_type & DRBD_GENLA_F_MANDATORY) {
22			nla->nla_type &= ~DRBD_GENLA_F_MANDATORY;
23			if (nla_type(nla) > maxtype)
24				return -EOPNOTSUPP;
25		}
26	}
27	return 0;
28}
29
30int drbd_nla_parse_nested(struct nlattr *tb[], int maxtype, struct nlattr *nla,
31			  const struct nla_policy *policy)
32{
33	int err;
34
35	err = drbd_nla_check_mandatory(maxtype, nla);
36	if (!err)
37		err = nla_parse_nested(tb, maxtype, nla, policy);
38
39	return err;
40}
41
42struct nlattr *drbd_nla_find_nested(int maxtype, struct nlattr *nla, int attrtype)
43{
44	int err;
45	/*
46	 * If any nested attribute has the DRBD_GENLA_F_MANDATORY flag set and
47	 * we don't know about that attribute, reject all the nested
48	 * attributes.
49	 */
50	err = drbd_nla_check_mandatory(maxtype, nla);
51	if (err)
52		return ERR_PTR(err);
53	return nla_find_nested(nla, attrtype);
54}
55