diff --git a/msg.c b/msg.c
index 4af9782..7edbdd2 100644
--- a/msg.c
+++ b/msg.c
@@ -379,7 +379,7 @@ int msg_pre_send(struct ptp_message *m)
 	return 0;
 }
 
-char *msg_type_string(int type)
+const char *msg_type_string(int type)
 {
 	switch (type) {
 	case SYNC:
diff --git a/msg.h b/msg.h
index 1fad5e9..7f471ca 100644
--- a/msg.h
+++ b/msg.h
@@ -298,7 +298,7 @@ int msg_pre_send(struct ptp_message *m);
  * @param type  Value of the messageType field as returned by @ref msg_type().
  * @return      String describing the message type.
  */
-char *msg_type_string(int type);
+const char *msg_type_string(int type);
 
 /**
  * Print messages for debugging purposes.
diff --git a/pmc.c b/pmc.c
index 7ea0368..077991b 100644
--- a/pmc.c
+++ b/pmc.c
@@ -109,7 +109,7 @@ struct management_id idtab[] = {
 	{ "PORT_DATA_SET_NP", PORT_DATA_SET_NP, do_set_action },
 };
 
-static char *action_string[] = {
+static const char *action_string[] = {
 	"GET",
 	"SET",
 	"RESPONSE",
@@ -711,7 +711,8 @@ static void usage(char *progname)
 
 int main(int argc, char *argv[])
 {
-	char *iface_name = NULL, *progname;
+	const char *iface_name = NULL;
+	char *progname;
 	int c, cnt, length, tmo = -1, batch_mode = 0, zero_datalen = 0;
 	char line[1024], *command = NULL;
 	enum transport_type transport_type = TRANS_UDP_IPV4;
diff --git a/pmc_common.c b/pmc_common.c
index 9b0720f..e52d68f 100644
--- a/pmc_common.c
+++ b/pmc_common.c
@@ -61,7 +61,7 @@ struct pmc {
 	int zero_length_gets;
 };
 
-struct pmc *pmc_create(enum transport_type transport_type, char *iface_name,
+struct pmc *pmc_create(enum transport_type transport_type, const char *iface_name,
 		       UInteger8 boundary_hops, UInteger8 domain_number,
 		       UInteger8 transport_specific, int zero_datalen)
 {
diff --git a/pmc_common.h b/pmc_common.h
index a7b4ae7..850d85f 100644
--- a/pmc_common.h
+++ b/pmc_common.h
@@ -25,7 +25,7 @@
 
 struct pmc;
 
-struct pmc *pmc_create(enum transport_type transport_type, char *iface_name,
+struct pmc *pmc_create(enum transport_type transport_type, const char *iface_name,
 		       UInteger8 boundary_hops, UInteger8 domain_number,
 		       UInteger8 transport_specific, int zero_datalen);
 
diff --git a/raw.c b/raw.c
index d87edbf..1bfc1bb 100644
--- a/raw.c
+++ b/raw.c
@@ -148,7 +148,7 @@ static int raw_close(struct transport *t, struct fdarray *fda)
 unsigned char ptp_dst_mac[MAC_LEN] = { PTP_DST_MAC };
 unsigned char p2p_dst_mac[MAC_LEN] = { P2P_DST_MAC };
 
-static int open_socket(char *name, int event)
+static int open_socket(const char *name, int event)
 {
 	struct sockaddr_ll addr;
 	int fd, index;
@@ -184,7 +184,7 @@ no_socket:
 	return -1;
 }
 
-static int raw_open(struct transport *t, char *name,
+static int raw_open(struct transport *t, const char *name,
 		    struct fdarray *fda, enum timestamp_type ts_type)
 {
 	struct raw *raw = container_of(t, struct raw, t);
diff --git a/sk.c b/sk.c
index 1fbbcc5..8d70d1a 100644
--- a/sk.c
+++ b/sk.c
@@ -40,7 +40,7 @@ int sk_check_fupsync;
 
 /* private methods */
 
-static int hwts_init(int fd, char *device, int rx_filter, int one_step)
+static int hwts_init(int fd, const char *device, int rx_filter, int one_step)
 {
 	struct ifreq ifreq;
 	struct hwtstamp_config cfg, req;
@@ -77,7 +77,7 @@ static int hwts_init(int fd, char *device, int rx_filter, int one_step)
 
 /* public methods */
 
-int sk_interface_index(int fd, char *name)
+int sk_interface_index(int fd, const char *name)
 {
 	struct ifreq ifreq;
 	int err;
@@ -102,7 +102,7 @@ int sk_general_init(int fd)
 	return 0;
 }
 
-int sk_get_ts_info(char *name, struct sk_ts_info *sk_info)
+int sk_get_ts_info(const char *name, struct sk_ts_info *sk_info)
 {
 #ifdef ETHTOOL_GET_TS_INFO
 	struct ethtool_ts_info info;
@@ -146,7 +146,7 @@ failed:
 	return -1;
 }
 
-int sk_interface_macaddr(char *name, unsigned char *mac, int len)
+int sk_interface_macaddr(const char *name, unsigned char *mac, int len)
 {
 	struct ifreq ifreq;
 	int err, fd;
@@ -172,7 +172,7 @@ int sk_interface_macaddr(char *name, unsigned char *mac, int len)
 	return 0;
 }
 
-int sk_interface_addr(char *name, int family, uint8_t *addr, int len)
+int sk_interface_addr(const char *name, int family, uint8_t *addr, int len)
 {
 	struct ifaddrs *ifaddr, *i;
 	int copy_len, result = -1;
@@ -285,7 +285,7 @@ int sk_receive(int fd, void *buf, int buflen,
 	return cnt;
 }
 
-int sk_timestamping_init(int fd, char *device, enum timestamp_type type,
+int sk_timestamping_init(int fd, const char *device, enum timestamp_type type,
 			 enum transport_type transport)
 {
 	int err, filter1, filter2 = 0, flags, one_step;
diff --git a/sk.h b/sk.h
index 895840f..ea338c1 100644
--- a/sk.h
+++ b/sk.h
@@ -44,7 +44,7 @@ struct sk_ts_info {
  * @param device  The name of the network interface of interest.
  * @return        The result from the SIOCGIFINDEX ioctl.
  */
-int sk_interface_index(int fd, char *device);
+int sk_interface_index(int fd, const char *device);
 
 /**
  * Prepare a given socket for PTP "general" messages.
@@ -59,7 +59,7 @@ int sk_general_init(int fd);
  * @param info      Struct containing obtained timestamping information.
  * @return          zero on success, negative on failure.
  */
-int sk_get_ts_info(char *name, struct sk_ts_info *sk_info);
+int sk_get_ts_info(const char *name, struct sk_ts_info *sk_info);
 
 /**
  * Obtain the MAC address of a network interface.
@@ -68,7 +68,7 @@ int sk_get_ts_info(char *name, struct sk_ts_info *sk_info);
  * @param len   Length of 'mac'
  * @return      Zero on success, non-zero otherwise.
  */
-int sk_interface_macaddr(char *name, unsigned char *mac, int len);
+int sk_interface_macaddr(const char *name, unsigned char *mac, int len);
 
 /**
  * Obtains the first IP address assigned to a network interface.
@@ -78,7 +78,7 @@ int sk_interface_macaddr(char *name, unsigned char *mac, int len);
  * @param len    Length of 'addr'
  * @return       The number of bytes written to addr on success, -1 otherwise.
  */
-int sk_interface_addr(char *name, int family, uint8_t *addr, int len);
+int sk_interface_addr(const char *name, int family, uint8_t *addr, int len);
 
 /**
  * Read a message from a socket.
@@ -100,7 +100,7 @@ int sk_receive(int fd, void *buf, int buflen,
  * @param transport   The type of transport used.
  * @return            Zero on success, non-zero otherwise.
  */
-int sk_timestamping_init(int fd, char *device, enum timestamp_type type,
+int sk_timestamping_init(int fd, const char *device, enum timestamp_type type,
 			 enum transport_type transport);
 
 /**
diff --git a/transport.c b/transport.c
index 3c70b2b..b5346e5 100644
--- a/transport.c
+++ b/transport.c
@@ -29,7 +29,7 @@ int transport_close(struct transport *t, struct fdarray *fda)
 	return t->close(t, fda);
 }
 
-int transport_open(struct transport *t, char *name,
+int transport_open(struct transport *t, const char *name,
 		   struct fdarray *fda, enum timestamp_type tt)
 {
 	return t->open(t, name, fda, tt);
diff --git a/transport.h b/transport.h
index 34934fe..aa2018b 100644
--- a/transport.h
+++ b/transport.h
@@ -64,7 +64,7 @@ struct transport;
 
 int transport_close(struct transport *t, struct fdarray *fda);
 
-int transport_open(struct transport *t, char *name,
+int transport_open(struct transport *t, const char *name,
 		   struct fdarray *fda, enum timestamp_type tt);
 
 int transport_recv(struct transport *t, int fd,
diff --git a/transport_private.h b/transport_private.h
index 0c553e1..7124f94 100644
--- a/transport_private.h
+++ b/transport_private.h
@@ -30,7 +30,7 @@ struct transport {
 
 	int (*close)(struct transport *t, struct fdarray *fda);
 
-	int (*open)(struct transport *t, char *name, struct fdarray *fda,
+	int (*open)(struct transport *t, const char *name, struct fdarray *fda,
 		    enum timestamp_type tt);
 
 	int (*recv)(struct transport *t, int fd, void *buf, int buflen,
diff --git a/udp.c b/udp.c
index 9628291..818cbfd 100644
--- a/udp.c
+++ b/udp.c
@@ -93,7 +93,7 @@ static int udp_close(struct transport *t, struct fdarray *fda)
 	return 0;
 }
 
-static int open_socket(char *name, struct in_addr mc_addr[2], short port)
+static int open_socket(const char *name, struct in_addr mc_addr[2], short port)
 {
 	struct sockaddr_in addr;
 	int fd, index, on = 1;
@@ -148,7 +148,7 @@ enum { MC_PRIMARY, MC_PDELAY };
 
 static struct in_addr mcast_addr[2];
 
-static int udp_open(struct transport *t, char *name, struct fdarray *fda,
+static int udp_open(struct transport *t, const char *name, struct fdarray *fda,
 		    enum timestamp_type ts_type)
 {
 	struct udp *udp = container_of(t, struct udp, t);
diff --git a/udp6.c b/udp6.c
index e0d1256..e26195b 100644
--- a/udp6.c
+++ b/udp6.c
@@ -100,7 +100,7 @@ static int udp6_close(struct transport *t, struct fdarray *fda)
 	return 0;
 }
 
-static int open_socket_ipv6(char *name, struct in6_addr mc_addr[2], short port,
+static int open_socket_ipv6(const char *name, struct in6_addr mc_addr[2], short port,
 			    int *interface_index)
 {
 	struct sockaddr_in6 addr;
@@ -158,7 +158,7 @@ enum { MC_PRIMARY, MC_PDELAY };
 
 static struct in6_addr mc6_addr[2];
 
-static int udp6_open(struct transport *t, char *name, struct fdarray *fda,
+static int udp6_open(struct transport *t, const char *name, struct fdarray *fda,
 		    enum timestamp_type ts_type)
 {
 	struct udp6 *udp6 = container_of(t, struct udp6, t);
diff --git a/uds.c b/uds.c
index 1dbfd6c..35f5ecc 100644
--- a/uds.c
+++ b/uds.c
@@ -46,7 +46,7 @@ static int uds_close(struct transport *t, struct fdarray *fda)
 	return 0;
 }
 
-static int uds_open(struct transport *t, char *name, struct fdarray *fda,
+static int uds_open(struct transport *t, const char *name, struct fdarray *fda,
 		    enum timestamp_type tt)
 {
 	int fd, err;
diff --git a/util.c b/util.c
index 4b0ef6b..56af8ef 100644
--- a/util.c
+++ b/util.c
@@ -28,7 +28,7 @@
 #define NS_PER_HOUR (3600 * NS_PER_SEC)
 #define NS_PER_DAY (24 * NS_PER_HOUR)
 
-char *ps_str[] = {
+const char *ps_str[] = {
 	"NONE",
 	"INITIALIZING",
 	"FAULTY",
@@ -42,7 +42,7 @@ char *ps_str[] = {
 	"GRAND_MASTER",
 };
 
-char *ev_str[] = {
+const char *ev_str[] = {
 	"NONE",
 	"POWERUP",
 	"INITIALIZE",
@@ -98,7 +98,7 @@ int str2pid(const char *s, struct PortIdentity *result)
 	return -1;
 }
 
-int generate_clock_identity(struct ClockIdentity *ci, char *name)
+int generate_clock_identity(struct ClockIdentity *ci, const char *name)
 {
 	unsigned char mac[6];
 	if (sk_interface_macaddr(name, mac, sizeof(mac)))
diff --git a/util.h b/util.h
index 8cf3890..3fae51c 100644
--- a/util.h
+++ b/util.h
@@ -26,12 +26,12 @@
 /**
  * Table of human readable strings, one for each port state.
  */
-extern char *ps_str[];
+extern const char *ps_str[];
 
 /**
  * Table of human readable strings, one for each port event.
  */
-extern char *ev_str[];
+extern const char *ev_str[];
 
 /**
  * Convert a clock identity into a human readable string.
@@ -64,7 +64,7 @@ char *pid2str(struct PortIdentity *id);
  */
 int str2pid(const char *s, struct PortIdentity *result);
 
-int generate_clock_identity(struct ClockIdentity *ci, char *name);
+int generate_clock_identity(struct ClockIdentity *ci, const char *name);
 
 /**
  * Copies a PTPText to a static_ptp_text. This copies the text into