[PATCH net-next 9/9] net/ipv4: Bail early if user only wants prefix entries

[David Ahern <dsahern@kernel.org>]

From: David Ahern <dsahern@gmail.com>

Unlike IPv6, IPv4 does not have routes marked with RTF_PREFIX_RT. If the
flag is set in the dump request, just return.

In the process of this change, move the CLONE check to use the new
filter flags.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 net/ipv4/fib_frontend.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index a99f2c7ba4e6..3e5e3c380dbb 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -884,10 +884,14 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 		err = ip_valid_fib_dump_req(net, nlh, &filter, cb->extack);
 		if (err < 0)
 			return err;
+	} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
+		struct rtmsg *rtm = nlmsg_data(nlh);
+
+		filter.flags = rtm->rtm_flags & (RTM_F_PREFIX | RTM_F_CLONED);
 	}
 
-	if (nlmsg_len(nlh) >= sizeof(struct rtmsg) &&
-	    ((struct rtmsg *)nlmsg_data(nlh))->rtm_flags & RTM_F_CLONED)
+	/* fib entries are never clones and ipv4 does not use prefix flag */
+	if (filter.flags & (RTM_F_PREFIX | RTM_F_CLONED))
 		return skb->len;
 
 	s_h = cb->args[0];
-- 
2.11.0