iproute2: Add support for CAN presume-ack feature

This patch makes CAN_CTRLMODE_PRESUME_ACK netlink feature configurable.
When enabled, the feature sets CAN controller in mode in which
acknowledgement absence is ignored.
Signed-off-by: Nikita Edward Baruzdin <nebaruzdin@gmail.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>

ip/iplink_can.c

@@ -37,6 +37,7 @@ static void print_usage(FILE *f)
 		"\t[ one-shot { on | off } ]\n"
 		"\t[ berr-reporting { on | off } ]\n"
 		"\t[ fd { on | off } ]\n"
+		"\t[ presume-ack { on | off } ]\n"
 		"\n"
 		"\t[ restart-ms TIME-MS ]\n"
 		"\t[ restart ]\n"
@@ -99,6 +100,7 @@ static void print_ctrlmode(FILE *f, __u32 cm)
 	_PF(CAN_CTRLMODE_ONE_SHOT, "ONE-SHOT");
 	_PF(CAN_CTRLMODE_BERR_REPORTING, "BERR-REPORTING");
 	_PF(CAN_CTRLMODE_FD, "FD");
+	_PF(CAN_CTRLMODE_PRESUME_ACK, "PRESUME-ACK");
 #undef _PF
 	if (cm)
 		fprintf(f, "%x", cm);
@@ -201,6 +203,10 @@ static int can_parse_opt(struct link_util *lu, int argc, char **argv,
 			NEXT_ARG();
 			set_ctrlmode("fd", *argv, &cm,
 				     CAN_CTRLMODE_FD);
+		} else if (matches(*argv, "presume-ack") == 0) {
+			NEXT_ARG();
+			set_ctrlmode("presume-ack", *argv, &cm,
+				     CAN_CTRLMODE_PRESUME_ACK);
 		} else if (matches(*argv, "restart") == 0) {
 			__u32 val = 1;