ip: link: add support for netdevsim device type

netdevsim is a new software device for testing kernel APIs
without any hardware attached.  Allow users to create such
devices.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>

ip/Makefile

@@ -10,7 +10,7 @@ IPOBJ=ip.o ipaddress.o ipaddrlabel.o iproute.o iprule.o ipnetns.o \
     link_iptnl.o link_gre6.o iplink_bond.o iplink_bond_slave.o iplink_hsr.o \
     iplink_bridge.o iplink_bridge_slave.o ipfou.o iplink_ipvlan.o \
     iplink_geneve.o iplink_vrf.o iproute_lwtunnel.o ipmacsec.o ipila.o \
-    ipvrf.o iplink_xstats.o ipseg6.o
+    ipvrf.o iplink_xstats.o ipseg6.o iplink_netdevsim.o
 
 RTMONOBJ=rtmon.o
 

ip/ipaddress.c

@@ -78,7 +78,7 @@ static void usage(void)
 	fprintf(stderr, "          bridge | bond | ipoib | ip6tnl | ipip | sit | vxlan | lowpan |\n");
 	fprintf(stderr, "          gre | gretap | erspan | ip6gre | ip6gretap | ip6erspan | vti |\n");
 	fprintf(stderr, "          nlmon | can | bond_slave | ipvlan | geneve | bridge_slave |\n");
-	fprintf(stderr, "          hsr | macsec\n");
+	fprintf(stderr, "          hsr | macsec | netdevsim\n");
 
 	exit(-1);
 }

ip/iplink.c

@@ -122,7 +122,7 @@ void iplink_usage(void)
 			"          bridge | bond | team | ipoib | ip6tnl | ipip | sit | vxlan |\n"
 			"          gre | gretap | erspan | ip6gre | ip6gretap | ip6erspan |\n"
 			"          vti | nlmon | team_slave | bond_slave | ipvlan | geneve |\n"
-			"          bridge_slave | vrf | macsec }\n");
+			"          bridge_slave | vrf | macsec | netdevsim }\n");
 	}
 	exit(-1);
 }

ip/iplink_netdevsim.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "utils.h"
+#include "ip_common.h"
+
+static void netdevsim_print_help(struct link_util *lu,
+				 int argc, char **argv, FILE *f)
+{
+	fprintf(f, "Usage: ... netdevsim\n");
+}
+
+struct link_util netdevsim_link_util = {
+	.id		= "netdevsim",
+	.print_help	= netdevsim_print_help,
+};

man/man8/ip-link.8.in

@@ -217,7 +217,8 @@ ip-link \- network device configuration
 .BR lowpan " |"
 .BR geneve " |"
 .BR vrf " |"
-.BR macsec " ]"
+.BR macsec " |"
+.BR netdevsim " ]"
 
 .ti -8
 .IR ETYPE " := [ " TYPE " |"
@@ -337,6 +338,9 @@ Link types:
 .sp
 .BR vrf
 - Interface for L3 VRF domains
+.sp
+.BR netdevsim
+- Interface for netdev API tests
 .in -8
 
 .TP