nexthop: Extract dump filtering parameters into a single structure

Requests to dump nexthops have many attributes in common with those that
requests to dump buckets of resilient NH groups will have. In order to make
reuse of this code simpler, convert the code to use a single structure with
filtering configuration instead of passing around the parameters one by
one.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/nexthop.c

@@ -1971,16 +1971,23 @@ static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 	goto out;
 }
 
-static bool nh_dump_filtered(struct nexthop *nh, int dev_idx, int master_idx,
-			     bool group_filter, u8 family)
+struct nh_dump_filter {
+	int dev_idx;
+	int master_idx;
+	bool group_filter;
+	bool fdb_filter;
+};
+
+static bool nh_dump_filtered(struct nexthop *nh,
+			     struct nh_dump_filter *filter, u8 family)
 {
 	const struct net_device *dev;
 	const struct nh_info *nhi;
 
-	if (group_filter && !nh->is_group)
+	if (filter->group_filter && !nh->is_group)
 		return true;
 
-	if (!dev_idx && !master_idx && !family)
+	if (!filter->dev_idx && !filter->master_idx && !family)
 		return false;
 
 	if (nh->is_group)
@@ -1991,26 +1998,26 @@ static bool nh_dump_filtered(struct nexthop *nh, int dev_idx, int master_idx,
 		return true;
 
 	dev = nhi->fib_nhc.nhc_dev;
-	if (dev_idx && (!dev || dev->ifindex != dev_idx))
+	if (filter->dev_idx && (!dev || dev->ifindex != filter->dev_idx))
 		return true;
 
-	if (master_idx) {
+	if (filter->master_idx) {
 		struct net_device *master;
 
 		if (!dev)
 			return true;
 
 		master = netdev_master_upper_dev_get((struct net_device *)dev);
-		if (!master || master->ifindex != master_idx)
+		if (!master || master->ifindex != filter->master_idx)
 			return true;
 	}
 
 	return false;
 }
 
-static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx,
-			     int *master_idx, bool *group_filter,
-			     bool *fdb_filter, struct netlink_callback *cb)
+static int nh_valid_dump_req(const struct nlmsghdr *nlh,
+			     struct nh_dump_filter *filter,
+			     struct netlink_callback *cb)
 {
 	struct netlink_ext_ack *extack = cb->extack;
 	struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_dump)];
@@ -2030,7 +2037,7 @@ static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx,
 			NL_SET_ERR_MSG(extack, "Invalid device index");
 			return -EINVAL;
 		}
-		*dev_idx = idx;
+		filter->dev_idx = idx;
 	}
 	if (tb[NHA_MASTER]) {
 		idx = nla_get_u32(tb[NHA_MASTER]);
@@ -2038,10 +2045,10 @@ static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx,
 			NL_SET_ERR_MSG(extack, "Invalid master device index");
 			return -EINVAL;
 		}
-		*master_idx = idx;
+		filter->master_idx = idx;
 	}
-	*group_filter = nla_get_flag(tb[NHA_GROUPS]);
-	*fdb_filter = nla_get_flag(tb[NHA_FDB]);
+	filter->group_filter = nla_get_flag(tb[NHA_GROUPS]);
+	filter->fdb_filter = nla_get_flag(tb[NHA_FDB]);
 
 	nhm = nlmsg_data(nlh);
 	if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
@@ -2055,17 +2062,15 @@ static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx,
 /* rtnl */
 static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	bool group_filter = false, fdb_filter = false;
 	struct nhmsg *nhm = nlmsg_data(cb->nlh);
-	int dev_filter_idx = 0, master_idx = 0;
 	struct net *net = sock_net(skb->sk);
 	struct rb_root *root = &net->nexthop.rb_root;
+	struct nh_dump_filter filter = {};
 	struct rb_node *node;
 	int idx = 0, s_idx;
 	int err;
 
-	err = nh_valid_dump_req(cb->nlh, &dev_filter_idx, &master_idx,
-				&group_filter, &fdb_filter, cb);
+	err = nh_valid_dump_req(cb->nlh, &filter, cb);
 	if (err < 0)
 		return err;
 
@@ -2077,8 +2082,7 @@ static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
 			goto cont;
 
 		nh = rb_entry(node, struct nexthop, rb_node);
-		if (nh_dump_filtered(nh, dev_filter_idx, master_idx,
-				     group_filter, nhm->nh_family))
+		if (nh_dump_filtered(nh, &filter, nhm->nh_family))
 			goto cont;
 
 		err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP,