From 141c6e6397d373126bba14982678dd6f1e9fbfd7 Mon Sep 17 00:00:00 2001 From: Andrea Claudi Date: Tue, 9 Jul 2019 15:16:51 +0200 Subject: [PATCH] ip tunnel: warn when changing IPv6 tunnel without tunnel name Tunnel change fails if a tunnel name is not specified while using 'ip -6 tunnel change'. However, no warning message is printed and no error code is returned. $ ip -6 tunnel add ip6tnl1 mode ip6gre local fd::1 remote fd::2 tos inherit ttl 127 encaplimit none dev dummy0 $ ip -6 tunnel change dev dummy0 local 2001:1234::1 remote 2001:1234::2 $ ip -6 tunnel show ip6tnl1 ip6tnl1: gre/ipv6 remote fd::2 local fd::1 dev dummy0 encaplimit none hoplimit 127 tclass inherit flowlabel 0x00000 (flowinfo 0x00000000) This commit checks if tunnel interface name is equal to an empty string: in this case, it prints a warning message to the user. It intentionally avoids to return an error to not break existing script setup. This is the output after this commit: $ ip -6 tunnel add ip6tnl1 mode ip6gre local fd::1 remote fd::2 tos inherit ttl 127 encaplimit none dev dummy0 $ ip -6 tunnel change dev dummy0 local 2001:1234::1 remote 2001:1234::2 Tunnel interface name not specified $ ip -6 tunnel show ip6tnl1 ip6tnl1: gre/ipv6 remote fd::2 local fd::1 dev dummy0 encaplimit none hoplimit 127 tclass inherit flowlabel 0x00000 (flowinfo 0x00000000) Reviewed-by: Matteo Croce Signed-off-by: Andrea Claudi Signed-off-by: Stephen Hemminger (cherry picked from commit d035cc1b4e83e2589ea2115cdc2fa7c6d3693a5a) Signed-off-by: Phil Sutter --- ip/ip6tunnel.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/ip/ip6tunnel.c b/ip/ip6tunnel.c index 999408ed801b1..e3da11eb4518e 100644 --- a/ip/ip6tunnel.c +++ b/ip/ip6tunnel.c @@ -386,6 +386,9 @@ static int do_add(int cmd, int argc, char **argv) if (parse_args(argc, argv, cmd, &p) < 0) return -1; + if (!*p.name) + fprintf(stderr, "Tunnel interface name not specified\n"); + if (p.proto == IPPROTO_GRE) basedev = "ip6gre0"; else if (p.i_flags & VTI_ISVTI) -- 2.22.0