netdev - [RFC iproute2] ip route: get: allow zero-length subnet mask

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Date:   Wed, 13 Feb 2019 20:09:53 +0000
From:   Luca Boccassi <bluca@...ian.org>
To:     netdev@...r.kernel.org
Cc:     stephen@...workplumber.org, Luca Boccassi <bluca@...ian.org>,
        Clément Hertling <wxcafe@...afe.net>
Subject: [RFC iproute2] ip route: get: allow zero-length subnet mask

A /0 subnet mask is theoretically valid, but ip route get doesn't allow
it:

$ ip route get 1.0.0.0/0
need at least a destination address

Remove the check so that it can go through:

$ ip/ip route get 1.0.0.0/0
1.0.0.0 via 192.168.1.1 dev eth0 src 192.168.1.91 uid 1000
    cache

Reported-by: Clément Hertling <wxcafe@...afe.net>
Signed-off-by: Luca Boccassi <bluca@...ian.org>
---
Stephen et al, this was reported by a Debian user:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=921737

It makes sense to me at a cursory glance, but sending as RFC as I'm
not 100% familiar with the route get function.

 ip/iproute.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/ip/iproute.c b/ip/iproute.c
index 5f58a3b3..d78f43d8 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -2041,11 +2041,6 @@ static int iproute_get(int argc, char **argv)
 		argc--; argv++;
 	}
 
-	if (req.r.rtm_dst_len == 0) {
-		fprintf(stderr, "need at least a destination address\n");
-		return -1;
-	}
-
 	if (idev || odev)  {
 		int idx;
 
-- 
2.20.1