Re: [PATCH net v5 5/6] ipv6: Dump route exceptions if requested

On 6/18/19 7:20 AM, Stefano Brivio wrote:

Changing the return code of rt6_dump_route should be a separate patch.

 {
 	struct rt6_rtnl_dump_arg *arg = (struct rt6_rtnl_dump_arg *) p_arg;
 	struct fib_dump_filter *filter = &arg->filter;
+	struct rt6_exception_bucket *bucket;
 	unsigned int flags = NLM_F_MULTI;
+	struct rt6_exception *rt6_ex;
 	struct net *net = arg->net;
+	int i, count = 0;
 
 	if (rt == net->ipv6.fib6_null_entry)
-		return 0;
+		return -1;
 
 	if ((filter->flags & RTM_F_PREFIX) &&
 	    !(rt->fib6_flags & RTF_PREFIX_RT)) {
 		/* success since this is not a prefix route */
-		return 1;
+		return -1;
 	}
-	if (filter->filter_set) {
-		if ((filter->rt_type && rt->fib6_type != filter->rt_type) ||
-		    (filter->dev && !fib6_info_uses_dev(rt, filter->dev)) ||
-		    (filter->protocol && rt->fib6_protocol != filter->protocol)) {
-			return 1;
-		}
+	if (filter->filter_set &&
+	    ((filter->rt_type  && rt->fib6_type != filter->rt_type) ||
+	     (filter->dev      && !fib6_info_uses_dev(rt, filter->dev)) ||
+	     (filter->protocol && rt->fib6_protocol != filter->protocol))) {
+		return -1;
+	}
+
+	if (filter->filter_set ||
+	    !filter->dump_routes || !filter->dump_exceptions) {
 		flags |= NLM_F_DUMP_FILTERED;
 	}
 
-	return rt6_fill_node(net, arg->skb, rt, NULL, NULL, NULL, 0,
-			     RTM_NEWROUTE, NETLINK_CB(arg->cb->skb).portid,
-			     arg->cb->nlh->nlmsg_seq, flags);
+	if (filter->dump_routes) {
+		if (skip) {
+			skip--;
+		} else {
+			if (rt6_fill_node(net, arg->skb, rt, NULL, NULL, NULL,
+					  0, RTM_NEWROUTE,
+					  NETLINK_CB(arg->cb->skb).portid,
+					  arg->cb->nlh->nlmsg_seq, flags)) {
+				return 0;
+			}
+			count++;
+		}
+	}
+
+	if (!filter->dump_exceptions)
+		return -1;
+

And the dump of the exception bucket should be a standalone function.
You will see why with net-next (it is per fib6_nh).

+	bucket = rcu_dereference(rt->rt6i_exception_bucket);
+	if (!bucket)
+		return -1;
+
+	for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+		hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {
+			if (skip) {
+				skip--;
+				continue;
+			}
+
+			/* Expiration of entries doesn't bump sernum, insertion
+			 * does. Removal is triggered by insertion, so we can
+			 * rely on the fact that if entries change between two
+			 * partial dumps, this node is scanned again completely,
+			 * see rt6_insert_exception() and fib6_dump_table().
+			 *
+			 * Count expired entries we go through as handled
+			 * entries that we'll skip next time, in case of partial
+			 * node dump. Otherwise, if entries expire meanwhile,
+			 * we'll skip the wrong amount.
+			 */
+			if (rt6_check_expired(rt6_ex->rt6i)) {
+				count++;
+				continue;
+			}
+
+			if (rt6_fill_node(net, arg->skb, rt, &rt6_ex->rt6i->dst,
+					  NULL, NULL, 0, RTM_NEWROUTE,
+					  NETLINK_CB(arg->cb->skb).portid,
+					  arg->cb->nlh->nlmsg_seq, flags)) {
+				return count;
+			}
+
+			count++;
+		}
+		bucket++;
+	}
+
+	return -1;
 }
 
 static int inet6_rtm_valid_getroute_req(struct sk_buff *skb,