fou: show usage even if the module is not available

Currently, the `ip fou` command tries to initialize a genl context even
when we just want to see the help for the command, which doesn't require
to talk to the kernel at all.

Delay genl initialization, which can fail if the module isn't loaded,
until the point where we will actually need it.

Fixes: 6928747b6e79 ("ip fou: Support to configure foo-over-udp RX")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>

diff --git a/ip/ipfou.c b/ip/ipfou.c
index 9f0911215749b976db94556a08f36451d32d4e7f..00dbe150710d2135bf62dfb47bd7c61168259133 100644 (file)
--- a/ip/ipfou.c
+++ b/ip/ipfou.c
@@ -136,19 +136,19 @@ static int do_del(int argc, char **argv)
 
 int do_ipfou(int argc, char **argv)
 {
-       if (genl_init_handle(&genl_rth, FOU_GENL_NAME, &genl_family))
-               exit(1);
-
        if (argc < 1)
                usage();
 
+       if (matches(*argv, "help") == 0)
+               usage();
+
+       if (genl_init_handle(&genl_rth, FOU_GENL_NAME, &genl_family))
+               exit(1);
+
        if (matches(*argv, "add") == 0)
                return do_add(argc-1, argv+1);
        if (matches(*argv, "delete") == 0)
                return do_del(argc-1, argv+1);
-       if (matches(*argv, "help") == 0)
-               usage();
-
        fprintf(stderr, "Command \"%s\" is unknown, try \"ip fou help\".\n", *argv);
        exit(-1);
 }