1 #include <linux/kernel.h> 2 #include <net/netlink.h> 3 #include <linux/drbd_genl_api.h> 4 #include "drbd_nla.h" 5 6 static 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 30 int 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 42 struct 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