Merge branch 'fib-rules-extack-support'

Roopa Prabhu says:

====================
fib rules extack support

First patch refactors code to move fib rule netlink handling
into a common function. This became obvious when adding
duplicate extack msgs in add and del paths. Second patch
adds extack msgs.

v2 - Dropped the ip route get support and selftests from
     the series to look at the input path some more (as pointed
     out by ido). Will come back to that next week when i have
     some time. resending just the extack part for now.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/fib_rules.h

@@ -75,7 +75,8 @@ struct fib_rules_ops {
 	int			(*configure)(struct fib_rule *,
 					     struct sk_buff *,
 					     struct fib_rule_hdr *,
-					     struct nlattr **);
+					     struct nlattr **,
+					     struct netlink_ext_ack *);
 	int			(*delete)(struct fib_rule *);
 	int			(*compare)(struct fib_rule *,
 					   struct fib_rule_hdr *,

net/core/fib_rules.c

@@ -387,247 +387,288 @@ unsigned int fib_rules_seq_read(struct net *net, int family)
 }
 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 
-static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
-			    struct fib_rules_ops *ops)
-{
-	int err = -EINVAL;
-
-	if (frh->src_len)
-		if (tb[FRA_SRC] == NULL ||
-		    frh->src_len > (ops->addr_size * 8) ||
-		    nla_len(tb[FRA_SRC]) != ops->addr_size)
-			goto errout;
-
-	if (frh->dst_len)
-		if (tb[FRA_DST] == NULL ||
-		    frh->dst_len > (ops->addr_size * 8) ||
-		    nla_len(tb[FRA_DST]) != ops->addr_size)
-			goto errout;
-
-	err = 0;
-errout:
-	return err;
-}
-
-static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
-		       struct nlattr **tb, struct fib_rule *rule)
+static struct fib_rule *rule_find(struct fib_rules_ops *ops,
+				  struct fib_rule_hdr *frh,
+				  struct nlattr **tb,
+				  struct fib_rule *rule,
+				  bool user_priority)
 {
 	struct fib_rule *r;
 
 	list_for_each_entry(r, &ops->rules_list, list) {
-		if (r->action != rule->action)
+		if (rule->action && r->action != rule->action)
 			continue;
 
-		if (r->table != rule->table)
+		if (rule->table && r->table != rule->table)
 			continue;
 
-		if (r->pref != rule->pref)
+		if (user_priority && r->pref != rule->pref)
 			continue;
 
-		if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
+		if (rule->iifname[0] &&
+		    memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 			continue;
 
-		if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
+		if (rule->oifname[0] &&
+		    memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 			continue;
 
-		if (r->mark != rule->mark)
+		if (rule->mark && r->mark != rule->mark)
 			continue;
 
-		if (r->mark_mask != rule->mark_mask)
+		if (rule->mark_mask && r->mark_mask != rule->mark_mask)
 			continue;
 
-		if (r->tun_id != rule->tun_id)
+		if (rule->tun_id && r->tun_id != rule->tun_id)
 			continue;
 
 		if (r->fr_net != rule->fr_net)
 			continue;
 
-		if (r->l3mdev != rule->l3mdev)
+		if (rule->l3mdev && r->l3mdev != rule->l3mdev)
 			continue;
 
-		if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
-		    !uid_eq(r->uid_range.end, rule->uid_range.end))
+		if (uid_range_set(&rule->uid_range) &&
+		    (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
+		    !uid_eq(r->uid_range.end, rule->uid_range.end)))
 			continue;
 
-		if (r->ip_proto != rule->ip_proto)
+		if (rule->ip_proto && r->ip_proto != rule->ip_proto)
 			continue;
 
-		if (!fib_rule_port_range_compare(&r->sport_range,
+		if (fib_rule_port_range_set(&rule->sport_range) &&
+		    !fib_rule_port_range_compare(&r->sport_range,
 						 &rule->sport_range))
 			continue;
 
-		if (!fib_rule_port_range_compare(&r->dport_range,
+		if (fib_rule_port_range_set(&rule->dport_range) &&
+		    !fib_rule_port_range_compare(&r->dport_range,
 						 &rule->dport_range))
 			continue;
 
 		if (!ops->compare(r, frh, tb))
 			continue;
-		return 1;
+		return r;
 	}
-	return 0;
+
+	return NULL;
 }
 
-int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
-		   struct netlink_ext_ack *extack)
+static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
+		       struct netlink_ext_ack *extack,
+		       struct fib_rules_ops *ops,
+		       struct nlattr *tb[],
+		       struct fib_rule **rule,
+		       bool *user_priority)
 {
 	struct net *net = sock_net(skb->sk);
 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
-	struct fib_rules_ops *ops = NULL;
-	struct fib_rule *rule, *r, *last = NULL;
-	struct nlattr *tb[FRA_MAX+1];
-	int err = -EINVAL, unresolved = 0;
-
-	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
-		goto errout;
+	struct fib_rule *nlrule = NULL;
+	int err = -EINVAL;
 
-	ops = lookup_rules_ops(net, frh->family);
-	if (ops == NULL) {
-		err = -EAFNOSUPPORT;
+	if (frh->src_len)
+		if (!tb[FRA_SRC] ||
+		    frh->src_len > (ops->addr_size * 8) ||
+		    nla_len(tb[FRA_SRC]) != ops->addr_size) {
+			NL_SET_ERR_MSG(extack, "Invalid source address");
 			goto errout;
 	}
 
-	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
-	if (err < 0)
-		goto errout;
-
-	err = validate_rulemsg(frh, tb, ops);
-	if (err < 0)
+	if (frh->dst_len)
+		if (!tb[FRA_DST] ||
+		    frh->dst_len > (ops->addr_size * 8) ||
+		    nla_len(tb[FRA_DST]) != ops->addr_size) {
+			NL_SET_ERR_MSG(extack, "Invalid dst address");
 			goto errout;
+	}
 
-	rule = kzalloc(ops->rule_size, GFP_KERNEL);
-	if (rule == NULL) {
+	nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
+	if (!nlrule) {
 		err = -ENOMEM;
 		goto errout;
 	}
-	refcount_set(&rule->refcnt, 1);
-	rule->fr_net = net;
+	refcount_set(&nlrule->refcnt, 1);
+	nlrule->fr_net = net;
 
-	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
-	                              : fib_default_rule_pref(ops);
+	if (tb[FRA_PRIORITY]) {
+		nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
+		*user_priority = true;
+	} else {
+		nlrule->pref = fib_default_rule_pref(ops);
+	}
 
-	rule->proto = tb[FRA_PROTOCOL] ?
+	nlrule->proto = tb[FRA_PROTOCOL] ?
 		nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
 
 	if (tb[FRA_IIFNAME]) {
 		struct net_device *dev;
 
-		rule->iifindex = -1;
-		nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
-		dev = __dev_get_by_name(net, rule->iifname);
+		nlrule->iifindex = -1;
+		nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
+		dev = __dev_get_by_name(net, nlrule->iifname);
 		if (dev)
-			rule->iifindex = dev->ifindex;
+			nlrule->iifindex = dev->ifindex;
 	}
 
 	if (tb[FRA_OIFNAME]) {
 		struct net_device *dev;
 
-		rule->oifindex = -1;
-		nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
-		dev = __dev_get_by_name(net, rule->oifname);
+		nlrule->oifindex = -1;
+		nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
+		dev = __dev_get_by_name(net, nlrule->oifname);
 		if (dev)
-			rule->oifindex = dev->ifindex;
+			nlrule->oifindex = dev->ifindex;
 	}
 
 	if (tb[FRA_FWMARK]) {
-		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
-		if (rule->mark)
+		nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
+		if (nlrule->mark)
 			/* compatibility: if the mark value is non-zero all bits
 			 * are compared unless a mask is explicitly specified.
 			 */
-			rule->mark_mask = 0xFFFFFFFF;
+			nlrule->mark_mask = 0xFFFFFFFF;
 	}
 
 	if (tb[FRA_FWMASK])
-		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
+		nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 
 	if (tb[FRA_TUN_ID])
-		rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
+		nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 
 	err = -EINVAL;
 	if (tb[FRA_L3MDEV]) {
 #ifdef CONFIG_NET_L3_MASTER_DEV
-		rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
-		if (rule->l3mdev != 1)
+		nlrule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
+		if (nlrule->l3mdev != 1)
 #endif
+			NL_SET_ERR_MSG(extack, "Invalid l3mdev");
 			goto errout_free;
 	}
 
-	rule->action = frh->action;
-	rule->flags = frh->flags;
-	rule->table = frh_get_table(frh, tb);
+	nlrule->action = frh->action;
+	nlrule->flags = frh->flags;
+	nlrule->table = frh_get_table(frh, tb);
 	if (tb[FRA_SUPPRESS_PREFIXLEN])
-		rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
+		nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 	else
-		rule->suppress_prefixlen = -1;
+		nlrule->suppress_prefixlen = -1;
 
 	if (tb[FRA_SUPPRESS_IFGROUP])
-		rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
+		nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 	else
-		rule->suppress_ifgroup = -1;
+		nlrule->suppress_ifgroup = -1;
 
 	if (tb[FRA_GOTO]) {
-		if (rule->action != FR_ACT_GOTO)
+		if (nlrule->action != FR_ACT_GOTO) {
+			NL_SET_ERR_MSG(extack, "Unexpected goto");
 			goto errout_free;
+		}
 
-		rule->target = nla_get_u32(tb[FRA_GOTO]);
+		nlrule->target = nla_get_u32(tb[FRA_GOTO]);
 		/* Backward jumps are prohibited to avoid endless loops */
-		if (rule->target <= rule->pref)
+		if (nlrule->target <= nlrule->pref) {
+			NL_SET_ERR_MSG(extack, "Backward goto not supported");
 			goto errout_free;
-
-		list_for_each_entry(r, &ops->rules_list, list) {
-			if (r->pref == rule->target) {
-				RCU_INIT_POINTER(rule->ctarget, r);
-				break;
-			}
 		}
-
-		if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
-			unresolved = 1;
-	} else if (rule->action == FR_ACT_GOTO)
+	} else if (nlrule->action == FR_ACT_GOTO) {
+		NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
 		goto errout_free;
+	}
 
-	if (rule->l3mdev && rule->table)
+	if (nlrule->l3mdev && nlrule->table) {
+		NL_SET_ERR_MSG(extack, "l3mdev and table are mutually exclusive");
 		goto errout_free;
+	}
 
 	if (tb[FRA_UID_RANGE]) {
 		if (current_user_ns() != net->user_ns) {
 			err = -EPERM;
+			NL_SET_ERR_MSG(extack, "No permission to set uid");
 			goto errout_free;
 		}
 
-		rule->uid_range = nla_get_kuid_range(tb);
+		nlrule->uid_range = nla_get_kuid_range(tb);
 
-		if (!uid_range_set(&rule->uid_range) ||
-		    !uid_lte(rule->uid_range.start, rule->uid_range.end))
+		if (!uid_range_set(&nlrule->uid_range) ||
+		    !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end)) {
+			NL_SET_ERR_MSG(extack, "Invalid uid range");
 			goto errout_free;
+		}
 	} else {
-		rule->uid_range = fib_kuid_range_unset;
+		nlrule->uid_range = fib_kuid_range_unset;
 	}
 
 	if (tb[FRA_IP_PROTO])
-		rule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
+		nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
 
 	if (tb[FRA_SPORT_RANGE]) {
 		err = nla_get_port_range(tb[FRA_SPORT_RANGE],
-					 &rule->sport_range);
-		if (err)
+					 &nlrule->sport_range);
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Invalid sport range");
 			goto errout_free;
 		}
+	}
 
 	if (tb[FRA_DPORT_RANGE]) {
 		err = nla_get_port_range(tb[FRA_DPORT_RANGE],
-					 &rule->dport_range);
-		if (err)
+					 &nlrule->dport_range);
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Invalid dport range");
 			goto errout_free;
 		}
+	}
+
+	*rule = nlrule;
+
+	return 0;
+
+errout_free:
+	kfree(nlrule);
+errout:
+	return err;
+}
+
+int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
+		   struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct fib_rule_hdr *frh = nlmsg_data(nlh);
+	struct fib_rules_ops *ops = NULL;
+	struct fib_rule *rule = NULL, *r, *last = NULL;
+	struct nlattr *tb[FRA_MAX + 1];
+	int err = -EINVAL, unresolved = 0;
+	bool user_priority = false;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
+		NL_SET_ERR_MSG(extack, "Invalid msg length");
+		goto errout;
+	}
+
+	ops = lookup_rules_ops(net, frh->family);
+	if (!ops) {
+		err = -EAFNOSUPPORT;
+		NL_SET_ERR_MSG(extack, "Rule family not supported");
+		goto errout;
+	}
+
+	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Error parsing msg");
+		goto errout;
+	}
+
+	err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
+	if (err)
+		goto errout;
 
 	if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
-	    rule_exists(ops, frh, tb, rule)) {
+	    rule_find(ops, frh, tb, rule, user_priority)) {
 		err = -EEXIST;
 		goto errout_free;
 	}
 
-	err = ops->configure(rule, skb, frh, tb);
+	err = ops->configure(rule, skb, frh, tb, extack);
 	if (err < 0)
 		goto errout_free;
 
@@ -636,6 +677,16 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		goto errout_free;
 
+	list_for_each_entry(r, &ops->rules_list, list) {
+		if (r->pref == rule->target) {
+			RCU_INIT_POINTER(rule->ctarget, r);
+			break;
+		}
+	}
+
+	if (rcu_dereference_protected(rule->ctarget, 1) == NULL)
+		unresolved = 1;
+
 	list_for_each_entry(r, &ops->rules_list, list) {
 		if (r->pref > rule->pref)
 			break;
@@ -690,115 +741,40 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 {
 	struct net *net = sock_net(skb->sk);
 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
-	struct fib_rule_port_range sprange = {0, 0};
-	struct fib_rule_port_range dprange = {0, 0};
 	struct fib_rules_ops *ops = NULL;
-	struct fib_rule *rule, *r;
+	struct fib_rule *rule = NULL, *r, *nlrule = NULL;
 	struct nlattr *tb[FRA_MAX+1];
-	struct fib_kuid_range range;
 	int err = -EINVAL;
+	bool user_priority = false;
 
-	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) {
+		NL_SET_ERR_MSG(extack, "Invalid msg length");
 		goto errout;
+	}
 
 	ops = lookup_rules_ops(net, frh->family);
 	if (ops == NULL) {
 		err = -EAFNOSUPPORT;
+		NL_SET_ERR_MSG(extack, "Rule family not supported");
 		goto errout;
 	}
 
 	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
-	if (err < 0)
-		goto errout;
-
-	err = validate_rulemsg(frh, tb, ops);
-	if (err < 0)
-		goto errout;
-
-	if (tb[FRA_UID_RANGE]) {
-		range = nla_get_kuid_range(tb);
-		if (!uid_range_set(&range)) {
-			err = -EINVAL;
+	if (err < 0) {
+		NL_SET_ERR_MSG(extack, "Error parsing msg");
 		goto errout;
 	}
-	} else {
-		range = fib_kuid_range_unset;
-	}
 
-	if (tb[FRA_SPORT_RANGE]) {
-		err = nla_get_port_range(tb[FRA_SPORT_RANGE],
-					 &sprange);
+	err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
 	if (err)
 		goto errout;
-	}
 
-	if (tb[FRA_DPORT_RANGE]) {
-		err = nla_get_port_range(tb[FRA_DPORT_RANGE],
-					 &dprange);
-		if (err)
+	rule = rule_find(ops, frh, tb, nlrule, user_priority);
+	if (!rule) {
+		err = -ENOENT;
 		goto errout;
 	}
 
-	list_for_each_entry(rule, &ops->rules_list, list) {
-		if (tb[FRA_PROTOCOL] &&
-		    (rule->proto != nla_get_u8(tb[FRA_PROTOCOL])))
-			continue;
-
-		if (frh->action && (frh->action != rule->action))
-			continue;
-
-		if (frh_get_table(frh, tb) &&
-		    (frh_get_table(frh, tb) != rule->table))
-			continue;
-
-		if (tb[FRA_PRIORITY] &&
-		    (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
-			continue;
-
-		if (tb[FRA_IIFNAME] &&
-		    nla_strcmp(tb[FRA_IIFNAME], rule->iifname))
-			continue;
-
-		if (tb[FRA_OIFNAME] &&
-		    nla_strcmp(tb[FRA_OIFNAME], rule->oifname))
-			continue;
-
-		if (tb[FRA_FWMARK] &&
-		    (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
-			continue;
-
-		if (tb[FRA_FWMASK] &&
-		    (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
-			continue;
-
-		if (tb[FRA_TUN_ID] &&
-		    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
-			continue;
-
-		if (tb[FRA_L3MDEV] &&
-		    (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
-			continue;
-
-		if (uid_range_set(&range) &&
-		    (!uid_eq(rule->uid_range.start, range.start) ||
-		     !uid_eq(rule->uid_range.end, range.end)))
-			continue;
-
-		if (tb[FRA_IP_PROTO] &&
-		    (rule->ip_proto != nla_get_u8(tb[FRA_IP_PROTO])))
-			continue;
-
-		if (fib_rule_port_range_set(&sprange) &&
-		    !fib_rule_port_range_compare(&rule->sport_range, &sprange))
-			continue;
-
-		if (fib_rule_port_range_set(&dprange) &&
-		    !fib_rule_port_range_compare(&rule->dport_range, &dprange))
-			continue;
-
-		if (!ops->compare(rule, frh, tb))
-			continue;
-
 	if (rule->flags & FIB_RULE_PERMANENT) {
 		err = -EPERM;
 		goto errout;
@@ -850,11 +826,12 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	fib_rule_put(rule);
 	flush_route_cache(ops);
 	rules_ops_put(ops);
+	kfree(nlrule);
 	return 0;
-	}
 
-	err = -ENOENT;
 errout:
+	if (nlrule)
+		kfree(nlrule);
 	rules_ops_put(ops);
 	return err;
 }

net/decnet/dn_rules.c

@@ -121,13 +121,16 @@ static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 
 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 				 struct fib_rule_hdr *frh,
-				 struct nlattr **tb)
+				 struct nlattr **tb,
+				 struct netlink_ext_ack *extack)
 {
 	int err = -EINVAL;
 	struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 
-	if (frh->tos)
+	if (frh->tos) {
+		NL_SET_ERR_MSG(extack, "Invalid tos value");
 		goto  errout;
+	}
 
 	if (rule->table == RT_TABLE_UNSPEC) {
 		if (rule->action == FR_ACT_TO_TBL) {

net/ipv4/fib_rules.c

@@ -213,14 +213,17 @@ static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
 
 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 			       struct fib_rule_hdr *frh,
-			       struct nlattr **tb)
+			       struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
 {
 	struct net *net = sock_net(skb->sk);
 	int err = -EINVAL;
 	struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 
-	if (frh->tos & ~IPTOS_TOS_MASK)
+	if (frh->tos & ~IPTOS_TOS_MASK) {
+		NL_SET_ERR_MSG(extack, "Invalid tos");
 		goto errout;
+	}
 
 	/* split local/main if they are not already split */
 	err = fib_unmerge(net);

net/ipv4/ipmr.c

@@ -201,7 +201,8 @@ static const struct nla_policy ipmr_rule_policy[FRA_MAX + 1] = {
 };
 
 static int ipmr_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
-			       struct fib_rule_hdr *frh, struct nlattr **tb)
+			       struct fib_rule_hdr *frh, struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
 {
 	return 0;
 }

net/ipv6/fib6_rules.c

@@ -245,15 +245,18 @@ static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
 
 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 			       struct fib_rule_hdr *frh,
-			       struct nlattr **tb)
+			       struct nlattr **tb,
+			       struct netlink_ext_ack *extack)
 {
 	int err = -EINVAL;
 	struct net *net = sock_net(skb->sk);
 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 
 	if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
-		if (rule->table == RT6_TABLE_UNSPEC)
+		if (rule->table == RT6_TABLE_UNSPEC) {
+			NL_SET_ERR_MSG(extack, "Invalid table");
 			goto errout;
+		}
 
 		if (fib6_new_table(net, rule->table) == NULL) {
 			err = -ENOBUFS;

net/ipv6/ip6mr.c

@@ -180,7 +180,8 @@ static const struct nla_policy ip6mr_rule_policy[FRA_MAX + 1] = {
 };
 
 static int ip6mr_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
-				struct fib_rule_hdr *frh, struct nlattr **tb)
+				struct fib_rule_hdr *frh, struct nlattr **tb,
+				struct netlink_ext_ack *extack)
 {
 	return 0;
 }