net/ipv6: Plumb support for filtering route dumps

Implement kernel side filtering of routes by table id, egress device
index, protocol, and route type. If the table id is given in the filter,
lookup the table and call fib6_dump_table directly for it.

Move the existing route flags check for prefix only routes to the new
filter.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 6 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 94e61fe47ff8..a51fc357a05c 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -583,10 +583,12 @@ static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 		err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb->extack);
 		if (err < 0)
 			return err;
-	}
+	} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
+		struct rtmsg *rtm = nlmsg_data(nlh);
 
-	s_h = cb->args[0];
-	s_e = cb->args[1];
+		if (rtm->rtm_flags & RTM_F_PREFIX)
+			arg.filter.flags = RTM_F_PREFIX;
+	}
 
 	w = (void *)cb->args[2];
 	if (!w) {
@@ -612,6 +614,20 @@ static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	arg.net = net;
 	w->args = &arg;
 
+	if (arg.filter.table_id) {
+		tb = fib6_get_table(net, arg.filter.table_id);
+		if (!tb) {
+			NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
+			return -ENOENT;
+		}
+
+		res = fib6_dump_table(tb, skb, cb);
+		goto out;
+	}
+
+	s_h = cb->args[0];
+	s_e = cb->args[1];
+
 	rcu_read_lock();
 	for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
 		e = 0;
@@ -621,16 +637,16 @@ static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 				goto next;
 			res = fib6_dump_table(tb, skb, cb);
 			if (res != 0)
-				goto out;
+				goto out_unlock;
 next:
 			e++;
 		}
 	}
-out:
+out_unlock:
 	rcu_read_unlock();
 	cb->args[1] = e;
 	cb->args[0] = h;
-
+out:
 	res = res < 0 ? res : skb->len;
 	if (res <= 0)
 		fib6_dump_end(cb);