diff --git a/cangw.c b/cangw.c
index b908fe4..ff76fd7 100644
--- a/cangw.c
+++ b/cangw.c
@@ -196,6 +196,7 @@ void print_usage(char *prg)
 	fprintf(stderr, "Options:   -t (preserve src_dev rx timestamp)\n");
 	fprintf(stderr, "           -e (echo sent frames - recommended on vcanx)\n");
 	fprintf(stderr, "           -i (allow to route to incoming interface)\n");
+	fprintf(stderr, "           -u <uid> (user defined modification identifier)\n");
 	fprintf(stderr, "           -l <hops> (limit the number of frame hops / routings)\n");
 	fprintf(stderr, "           -f <filter> (set CAN filter)\n");
 	fprintf(stderr, "           -m <mod> (set frame modifications)\n");
@@ -418,6 +419,7 @@ int parse_rtlist(char *prgname, unsigned char *rxbuf, int len)
 			case CGW_MOD_OR:
 			case CGW_MOD_XOR:
 			case CGW_MOD_SET:
+			case CGW_MOD_UID:
 			case CGW_LIM_HOPS:
 			case CGW_CS_XOR:
 			case CGW_CS_CRC8:
@@ -491,6 +493,10 @@ int parse_rtlist(char *prgname, unsigned char *rxbuf, int len)
 				printmod("SET", RTA_DATA(rta));
 				break;
 
+			case CGW_MOD_UID:
+				printf("-u %X ", *(__u32 *)RTA_DATA(rta));
+				break;
+
 			case CGW_LIM_HOPS:
 				printf("-l %d ", *(__u8 *)RTA_DATA(rta));
 				break;
@@ -551,6 +557,7 @@ int main(int argc, char **argv)
 	struct nlmsgerr *rte;
 	unsigned int src_ifindex = 0;
 	unsigned int dst_ifindex = 0;
+	__u32 uid = 0;
 	__u8 limit_hops = 0;
 	__u16 flags = 0;
 	int len;
@@ -570,7 +577,7 @@ int main(int argc, char **argv)
 	memset(&cs_xor, 0, sizeof(cs_xor));
 	memset(&cs_crc8, 0, sizeof(cs_crc8));
 
-	while ((opt = getopt(argc, argv, "ADFLs:d:teil:f:c:p:x:m:?")) != -1) {
+	while ((opt = getopt(argc, argv, "ADFLs:d:teiu:l:f:c:p:x:m:?")) != -1) {
 		switch (opt) {
 
 		case 'A':
@@ -613,6 +620,10 @@ int main(int argc, char **argv)
 			flags |= CGW_FLAGS_CAN_IIF_TX_OK;
 			break;
 
+		case 'u':
+			uid = strtoul(optarg, (char **)NULL, 16);
+			break;
+
 		case 'l':
 			if (sscanf(optarg, "%hhd", &limit_hops) != 1 || !(limit_hops)) {
 				printf("Bad hop limit definition '%s'.\n", optarg);
@@ -757,6 +768,9 @@ int main(int argc, char **argv)
 	if (have_cs_xor)
 		addattr_l(&req.nh, sizeof(req), CGW_CS_XOR, &cs_xor, sizeof(cs_xor));
 
+	if (uid)
+		addattr_l(&req.nh, sizeof(req), CGW_MOD_UID, &uid, sizeof(__u32));
+
 	if (limit_hops)
 		addattr_l(&req.nh, sizeof(req), CGW_LIM_HOPS, &limit_hops, sizeof(__u8));
 
diff --git a/include/linux/can/gw.h b/include/linux/can/gw.h
index 844c896..210e7c9 100644
--- a/include/linux/can/gw.h
+++ b/include/linux/can/gw.h
@@ -78,6 +78,7 @@ enum {
 	CGW_FILTER,	/* specify struct can_filter on source CAN device */
 	CGW_DELETED,	/* number of deleted CAN frames (see max_hops param) */
 	CGW_LIM_HOPS,	/* limit the number of hops of this specific rule */
+	CGW_MOD_UID,	/* user defined identifier for modification updates */
 	__CGW_MAX
 };
 
@@ -162,6 +163,10 @@ enum {
  * load time of the can-gw module). This value is used to reduce the number of
  * possible hops for this gateway rule to a value smaller then max_hops.
  *
+ * CGW_MOD_UID (length 4 bytes):
+ * Optional non-zero user defined routing job identifier to alter existing
+ * modification settings at runtime.
+ *
  * CGW_CS_XOR (length 4 bytes):
  * Set a simple XOR checksum starting with an initial value into
  * data[result-idx] using data[start-idx] .. data[end-idx]