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 <d...@cumulusnetworks.com>
---
ip/iproute.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/ip/iproute.c b/ip/iproute.c
index e433de8be189..52dbdc7dea36 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);
--
2.1.4
