From 11f2c753155b1cdcc3dd62769183b462ad85ef43 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 19 Jan 2017 09:08:21 -0800 Subject: [PATCH] ip route: error out on multiple via without nexthop keyword To specify multiple nexthops in a route the user is expected to use the "nexthop" keyword which ip route uses to create the RTA_MULTIPATH. However, ip route always accepts multiple 'via' keywords where only the last one is used in the route leading to confusion. For example, ip accepts this syntax: $ ip ro add vrf red 1.1.1.0/24 via 10.100.1.18 via 10.100.2.18 but the route entered inserted by the kernel is just the last gateway: 1.1.1.0/24 via 10.100.2.18 dev eth2 which is not the full request from the user. Detect the presense of multiple 'via' and give the user a hint to add nexthop: $ ip ro add vrf red 1.1.1.0/24 via 10.100.1.18 via 10.100.2.18 Error: argument "via" is wrong: use nexthop syntax to specify multiple via Signed-off-by: David Ahern Signed-off-by: Stephen Hemminger --- ip/iproute.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/ip/iproute.c b/ip/iproute.c index e433de8be..52dbdc7de 100644 --- a/ip/iproute.c +++ b/ip/iproute.c @@ -881,6 +881,10 @@ static int iproute_modify(int cmd, unsigned int flags, int argc, char **argv) inet_prefix addr; int family; + if (gw_ok) { + invarg("use nexthop syntax to specify multiple via\n", + *argv); + } gw_ok = 1; NEXT_ARG(); family = read_family(*argv); -- 2.47.2