diff --git a/usr.sbin/ctld/Makefile b/usr.sbin/ctld/Makefile
--- a/usr.sbin/ctld/Makefile
+++ b/usr.sbin/ctld/Makefile
@@ -4,9 +4,9 @@
 .PATH:  ${SRCTOP}/contrib/libucl/include
 
 PACKAGE=	iscsi
-PROG=		ctld
-SRCS=		ctld.c conf.c discovery.c isns.c kernel.c
-SRCS+=		login.c parse.y token.l y.tab.h uclparse.c
+PROG_CXX=	ctld
+SRCS=		ctld.cc conf.cc discovery.cc isns.cc kernel.cc
+SRCS+=		login.cc parse.y token.l y.tab.h uclparse.cc
 CFLAGS+=	-I${.CURDIR}
 CFLAGS+=	-I${SRCTOP}/sys
 CFLAGS+=	-I${SRCTOP}/sys/cam/ctl
diff --git a/usr.sbin/ctld/conf.h b/usr.sbin/ctld/conf.h
--- a/usr.sbin/ctld/conf.h
+++ b/usr.sbin/ctld/conf.h
@@ -36,6 +36,8 @@
  * ctld.
  */
 
+__BEGIN_DECLS
+
 bool	auth_group_start(const char *name);
 void	auth_group_finish(void);
 bool	auth_group_add_chap(const char *user, const char *secret);
@@ -97,4 +99,6 @@
 
 bool	parse_conf(const char *path);
 
+__END_DECLS
+
 #endif /* !__CONF_H__ */
diff --git a/usr.sbin/ctld/conf.c b/usr.sbin/ctld/conf.cc
rename from usr.sbin/ctld/conf.c
rename to usr.sbin/ctld/conf.cc
diff --git a/usr.sbin/ctld/ctld.c b/usr.sbin/ctld/ctld.cc
rename from usr.sbin/ctld/ctld.c
rename to usr.sbin/ctld/ctld.cc
--- a/usr.sbin/ctld/ctld.c
+++ b/usr.sbin/ctld/ctld.cc
@@ -77,6 +77,9 @@
 #ifdef ICL_KERNEL_PROXY
 	.pdu_receive_proxy = pdu_receive_proxy,
 	.pdu_send_proxy = pdu_send_proxy,
+#else
+	.pdu_receive_proxy = nullptr,
+	.pdu_send_proxy = nullptr,
 #endif
 	.fail = pdu_fail,
 };
@@ -95,7 +98,7 @@
 {
 	struct conf *conf;
 
-	conf = calloc(1, sizeof(*conf));
+	conf = reinterpret_cast<struct conf *>(calloc(1, sizeof(*conf)));
 	if (conf == NULL)
 		log_err(1, "calloc");
 	TAILQ_INIT(&conf->conf_luns);
@@ -145,7 +148,7 @@
 {
 	struct auth *auth;
 
-	auth = calloc(1, sizeof(*auth));
+	auth = reinterpret_cast<struct auth *>(calloc(1, sizeof(*auth)));
 	if (auth == NULL)
 		log_err(1, "calloc");
 	auth->a_auth_group = ag;
@@ -303,7 +306,7 @@
 {
 	struct auth_name *an;
 
-	an = calloc(1, sizeof(*an));
+	an = reinterpret_cast<struct auth_name *>(calloc(1, sizeof(*an)));
 	if (an == NULL)
 		log_err(1, "calloc");
 	an->an_auth_group = ag;
@@ -361,7 +364,7 @@
 	char *net, *mask, *str, *tmp;
 	int len, dm, m;
 
-	ap = calloc(1, sizeof(*ap));
+	ap = reinterpret_cast<struct auth_portal *>(calloc(1, sizeof(*ap)));
 	if (ap == NULL)
 		log_err(1, "calloc");
 	ap->ap_auth_group = ag;
@@ -494,7 +497,7 @@
 		}
 	}
 
-	ag = calloc(1, sizeof(*ag));
+	ag = reinterpret_cast<struct auth_group *>(calloc(1, sizeof(*ag)));
 	if (ag == NULL)
 		log_err(1, "calloc");
 	if (name != NULL)
@@ -547,7 +550,7 @@
 {
 	struct portal *portal;
 
-	portal = calloc(1, sizeof(*portal));
+	portal = reinterpret_cast<struct portal *>(calloc(1, sizeof(*portal)));
 	if (portal == NULL)
 		log_err(1, "calloc");
 	TAILQ_INIT(&portal->p_targets);
@@ -578,7 +581,7 @@
 		return (NULL);
 	}
 
-	pg = calloc(1, sizeof(*pg));
+	pg = reinterpret_cast<struct portal_group *>(calloc(1, sizeof(*pg)));
 	if (pg == NULL)
 		log_err(1, "calloc");
 	pg->pg_name = checked_strdup(name);
@@ -711,7 +714,7 @@
 {
 	struct isns *isns;
 
-	isns = calloc(1, sizeof(*isns));
+	isns = reinterpret_cast<struct isns *>(calloc(1, sizeof(*isns)));
 	if (isns == NULL)
 		log_err(1, "calloc");
 	isns->i_conf = conf;
@@ -973,7 +976,7 @@
 {
 	struct pport *pp;
 
-	pp = calloc(1, sizeof(*pp));
+	pp = reinterpret_cast<struct pport *>(calloc(1, sizeof(*pp)));
 	if (pp == NULL)
 		log_err(1, "calloc");
 	pp->pp_kports = kports;
@@ -1032,7 +1035,7 @@
 		free(name);
 		return (NULL);
 	}
-	port = calloc(1, sizeof(*port));
+	port = reinterpret_cast<struct port *>(calloc(1, sizeof(*port)));
 	if (port == NULL)
 		log_err(1, "calloc");
 	port->p_conf = conf;
@@ -1077,7 +1080,7 @@
 		free(name);
 		return (NULL);
 	}
-	port = calloc(1, sizeof(*port));
+	port = reinterpret_cast<struct port *>(calloc(1, sizeof(*port)));
 	if (port == NULL)
 		log_err(1, "calloc");
 	port->p_conf = conf;
@@ -1106,7 +1109,7 @@
 		free(name);
 		return (NULL);
 	}
-	port = calloc(1, sizeof(*port));
+	port = reinterpret_cast<struct port *>(calloc(1, sizeof(*port)));
 	if (port == NULL)
 		log_err(1, "calloc");
 	port->p_conf = conf;
@@ -1187,7 +1190,7 @@
 	if (valid_iscsi_name(name, log_warnx) == false) {
 		return (NULL);
 	}
-	targ = calloc(1, sizeof(*targ));
+	targ = reinterpret_cast<struct target *>(calloc(1, sizeof(*targ)));
 	if (targ == NULL)
 		log_err(1, "calloc");
 	targ->t_name = checked_strdup(name);
@@ -1245,7 +1248,7 @@
 		return (NULL);
 	}
 
-	lun = calloc(1, sizeof(*lun));
+	lun = reinterpret_cast<struct lun *>(calloc(1, sizeof(*lun)));
 	if (lun == NULL)
 		log_err(1, "calloc");
 	lun->l_conf = conf;
@@ -1365,7 +1368,7 @@
 {
 	struct ctld_connection *conn;
 
-	conn = calloc(1, sizeof(*conn));
+	conn = reinterpret_cast<struct ctld_connection *>(calloc(1, sizeof(*conn)));
 	if (conn == NULL)
 		log_err(1, "calloc");
 	connection_init(&conn->conn, &conn_ops, proxy_mode);
@@ -2254,7 +2257,7 @@
 
 			switch (kev.filter) {
 			case EVFILT_READ:
-				portal = kev.udata;
+				portal = reinterpret_cast<struct portal *>(kev.udata);
 				assert(portal->p_socket == (int)kev.ident);
 
 				client_salen = sizeof(client_sa);
diff --git a/usr.sbin/ctld/discovery.c b/usr.sbin/ctld/discovery.cc
rename from usr.sbin/ctld/discovery.c
rename to usr.sbin/ctld/discovery.cc
diff --git a/usr.sbin/ctld/isns.c b/usr.sbin/ctld/isns.cc
rename from usr.sbin/ctld/isns.c
rename to usr.sbin/ctld/isns.cc
--- a/usr.sbin/ctld/isns.c
+++ b/usr.sbin/ctld/isns.cc
@@ -48,14 +48,14 @@
 {
 	struct isns_req *req;
 
-	req = calloc(1, sizeof(struct isns_req));
+	req = reinterpret_cast<struct isns_req *>(calloc(1, sizeof(struct isns_req)));
 	if (req == NULL) {
 		log_err(1, "calloc");
 		return (NULL);
 	}
 	req->ir_buflen = sizeof(struct isns_hdr);
 	req->ir_usedlen = 0;
-	req->ir_buf = calloc(1, req->ir_buflen);
+	req->ir_buf = reinterpret_cast<uint8_t *>(calloc(1, req->ir_buflen));
 	if (req->ir_buf == NULL) {
 		free(req);
 		log_err(1, "calloc");
@@ -101,7 +101,7 @@
 		log_err(1, "realloc");
 		return (1);
 	}
-	req->ir_buf = newbuf;
+	req->ir_buf = reinterpret_cast<uint8_t *>(newbuf);
 	req->ir_buflen = newlen;
 	return (0);
 }
diff --git a/usr.sbin/ctld/kernel.c b/usr.sbin/ctld/kernel.cc
rename from usr.sbin/ctld/kernel.c
rename to usr.sbin/ctld/kernel.cc
--- a/usr.sbin/ctld/kernel.c
+++ b/usr.sbin/ctld/kernel.cc
@@ -170,7 +170,7 @@
 			log_errx(1, "%s: improper lun element nesting",
 			    __func__);
 
-		cur_lun = calloc(1, sizeof(*cur_lun));
+		cur_lun = reinterpret_cast<struct cctl_lun *>(calloc(1, sizeof(*cur_lun)));
 		if (cur_lun == NULL)
 			log_err(1, "%s: cannot allocate %zd bytes", __func__,
 			    sizeof(*cur_lun));
@@ -287,7 +287,7 @@
 			log_errx(1, "%s: improper port element nesting (%s)",
 			    __func__, name);
 
-		cur_port = calloc(1, sizeof(*cur_port));
+		cur_port = reinterpret_cast<struct cctl_port *>(calloc(1, sizeof(*cur_port)));
 		if (cur_port == NULL)
 			log_err(1, "%s: cannot allocate %zd bytes", __func__,
 			    sizeof(*cur_port));
@@ -422,7 +422,7 @@
 	str = NULL;
 	len = 4096;
 retry:
-	str = realloc(str, len);
+	str = reinterpret_cast<char *>(realloc(str, len));
 	if (str == NULL)
 		log_err(1, "realloc");
 
@@ -471,7 +471,7 @@
 	str = NULL;
 	len = 4096;
 retry_port:
-	str = realloc(str, len);
+	str = reinterpret_cast<char *>(realloc(str, len));
 	if (str == NULL)
 		log_err(1, "realloc");
 
@@ -691,13 +691,13 @@
 	req.reqdata.create.device_type = lun->l_device_type;
 
 	if (lun->l_serial != NULL) {
-		strncpy(req.reqdata.create.serial_num, lun->l_serial,
+		strncpy((char *)req.reqdata.create.serial_num, lun->l_serial,
 			sizeof(req.reqdata.create.serial_num));
 		req.reqdata.create.flags |= CTL_LUN_FLAG_SERIAL_NUM;
 	}
 
 	if (lun->l_device_id != NULL) {
-		strncpy(req.reqdata.create.device_id, lun->l_device_id,
+		strncpy((char *)req.reqdata.create.device_id, lun->l_device_id,
 			sizeof(req.reqdata.create.device_id));
 		req.reqdata.create.flags |= CTL_LUN_FLAG_DEVID;
 	}
diff --git a/usr.sbin/ctld/login.c b/usr.sbin/ctld/login.cc
rename from usr.sbin/ctld/login.c
rename to usr.sbin/ctld/login.cc
--- a/usr.sbin/ctld/login.c
+++ b/usr.sbin/ctld/login.cc
@@ -47,7 +47,7 @@
 #define	MAX_DATA_SEGMENT_LENGTH		(128 * 1024)
 
 static void login_send_error(struct pdu *request,
-    char class, char detail);
+    char error_class, char detail);
 
 static void
 kernel_limits(const char *offload, int s, int *max_recv_dsl, int *max_send_dsl,
@@ -230,16 +230,16 @@
 }
 
 static void
-login_send_error(struct pdu *request, char class, char detail)
+login_send_error(struct pdu *request, char error_class, char detail)
 {
 	struct pdu *response;
 	struct iscsi_bhs_login_response *bhslr2;
 
 	log_debugx("sending Login Response PDU with failure class 0x%x/0x%x; "
-	    "see next line for reason", class, detail);
+	    "see next line for reason", error_class, detail);
 	response = login_new_response(request);
 	bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
-	bhslr2->bhslr_status_class = class;
+	bhslr2->bhslr_status_class = error_class;
 	bhslr2->bhslr_status_detail = detail;
 
 	pdu_send(response);
diff --git a/usr.sbin/ctld/uclparse.c b/usr.sbin/ctld/uclparse.cc
rename from usr.sbin/ctld/uclparse.c
rename to usr.sbin/ctld/uclparse.cc