diff --git a/nsm.c b/nsm.c
index 1a6475f..43daf59 100644
--- a/nsm.c
+++ b/nsm.c
@@ -359,43 +359,14 @@ static int nsm_request(struct nsm *nsm, char *target)
 {
 	enum transport_type type = transport_type(nsm->trp);
 	UInteger8 transportSpecific;
-	unsigned char mac[MAC_LEN];
-	struct in_addr ipv4_addr;
 	struct ptp_message *msg;
 	struct tlv_extra *extra;
 	Integer64 asymmetry;
 	struct address dst;
 	int cnt, err;
 
-	memset(&dst, 0, sizeof(dst));
-
-	switch (type) {
-	case TRANS_UDS:
-	case TRANS_UDP_IPV6:
-	case TRANS_DEVICENET:
-	case TRANS_CONTROLNET:
-	case TRANS_PROFINET:
-		pr_err("sorry, NSM not support with this transport");
+	if (str2addr(type, target, &dst)) {
 		return -1;
-	case TRANS_UDP_IPV4:
-		if (!inet_aton(target, &ipv4_addr)) {
-			pr_err("bad IPv4 address");
-			return -1;
-		}
-		dst.sin.sin_family = AF_INET;
-		dst.sin.sin_addr = ipv4_addr;
-		dst.len = sizeof(dst.sin);
-		break;
-	case TRANS_IEEE_802_3:
-		if (str2mac(target, mac)) {
-			pr_err("bad Layer-2 address");
-			return -1;
-		}
-		dst.sll.sll_family = AF_PACKET;
-		dst.sll.sll_halen = MAC_LEN;
-		memcpy(&dst.sll.sll_addr, mac, MAC_LEN);
-		dst.len = sizeof(dst.sll);
-		break;
 	}
 
 	msg = msg_allocate();
diff --git a/util.c b/util.c
index 2eacafc..799147a 100644
--- a/util.c
+++ b/util.c
@@ -139,6 +139,44 @@ char *portaddr2str(struct PortAddress *addr)
 	return buf;
 }
 
+int str2addr(enum transport_type type, const char *s, struct address *addr)
+{
+	unsigned char mac[MAC_LEN];
+	struct in_addr ipv4_addr;
+
+	memset(addr, 0, sizeof(*addr));
+
+	switch (type) {
+	case TRANS_UDS:
+	case TRANS_UDP_IPV6:
+	case TRANS_DEVICENET:
+	case TRANS_CONTROLNET:
+	case TRANS_PROFINET:
+		pr_err("sorry, cannot convert addresses for this transport");
+		return -1;
+	case TRANS_UDP_IPV4:
+		if (!inet_aton(s, &ipv4_addr)) {
+			pr_err("bad IPv4 address");
+			return -1;
+		}
+		addr->sin.sin_family = AF_INET;
+		addr->sin.sin_addr = ipv4_addr;
+		addr->len = sizeof(addr->sin);
+		break;
+	case TRANS_IEEE_802_3:
+		if (str2mac(s, mac)) {
+			pr_err("bad Layer-2 address");
+			return -1;
+		}
+		addr->sll.sll_family = AF_PACKET;
+		addr->sll.sll_halen = MAC_LEN;
+		memcpy(&addr->sll.sll_addr, mac, MAC_LEN);
+		addr->len = sizeof(addr->sll);
+		break;
+	}
+	return 0;
+}
+
 int str2mac(const char *s, unsigned char mac[MAC_LEN])
 {
 	unsigned char buf[MAC_LEN];
diff --git a/util.h b/util.h
index 256a799..29ba5ca 100644
--- a/util.h
+++ b/util.h
@@ -23,8 +23,10 @@
 #include <string.h>
 #include <time.h>
 
+#include "address.h"
 #include "ddt.h"
 #include "ether.h"
+#include "transport.h"
 
 #define MAX_PRINT_BYTES 16
 #define BIN_BUF_SIZE (MAX_PRINT_BYTES * 3 + 1)
@@ -104,6 +106,15 @@ static inline int pid_eq(struct PortIdentity *a, struct PortIdentity *b)
 	return memcmp(a, b, sizeof(*a)) == 0;
 }
 
+/**
+ * Convert a string containing a network address into binary form.
+ * @param type  The network transport type of the address.
+ * @param s     String in human readable form.
+ * @param addr  Pointer to a buffer to hold the result.
+ * @return Zero on success, or -1 if the string is incorrectly formatted.
+ */
+int str2addr(enum transport_type type, const char *s, struct address *addr);
+
 /**
  * Scan a string containing a MAC address and convert it into binary form.
  *