Make the transport layer more opaque.

Although the UDP/IPv4 layer does not need any state per instance (other
than the two file descriptors), the raw Ethernet layer will need this.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

port.c

@@ -40,7 +40,7 @@
 struct port {
 	char *name;
 	struct clock *clock;
-	struct transport *transport;
+	struct transport *trp;
 	enum timestamp_type timestamping;
 	struct fdarray fda;
 	struct foreign_clock *best;
@@ -351,7 +351,7 @@ static int port_delay_request(struct port *p)
 	if (msg_pre_send(msg))
 		goto out;
 
-	cnt = p->transport->send(&p->fda, 1, msg, pdulen, &msg->hwts);
+	cnt = transport_send(p->trp, &p->fda, 1, msg, pdulen, &msg->hwts);
 	if (cnt <= 0) {
 		pr_err("port %hu: send delay request failed", portnum(p));
 		goto out;
@@ -420,7 +420,7 @@ static int port_tx_announce(struct port *p)
 		err = -1;
 		goto out;
 	}
-	cnt = p->transport->send(&p->fda, 0, msg, pdulen, &msg->hwts);
+	cnt = transport_send(p->trp, &p->fda, 0, msg, pdulen, &msg->hwts);
 	if (cnt <= 0) {
 		pr_err("port %hu: send announce failed", portnum(p));
 		err = -1;
@@ -464,7 +464,7 @@ static int port_tx_sync(struct port *p)
 		err = -1;
 		goto out;
 	}
-	cnt = p->transport->send(&p->fda, 1, msg, pdulen, &msg->hwts);
+	cnt = transport_send(p->trp, &p->fda, 1, msg, pdulen, &msg->hwts);
 	if (cnt <= 0) {
 		pr_err("port %hu: send sync failed", portnum(p));
 		err = -1;
@@ -497,7 +497,7 @@ static int port_tx_sync(struct port *p)
 		err = -1;
 		goto out;
 	}
-	cnt = p->transport->send(&p->fda, 0, fup, pdulen, &fup->hwts);
+	cnt = transport_send(p->trp, &p->fda, 0, fup, pdulen, &fup->hwts);
 	if (cnt <= 0) {
 		pr_err("port %hu: send follow up failed", portnum(p));
 		err = -1;
@@ -531,7 +531,7 @@ static int port_initialize(struct port *p)
 			goto no_timers;
 		}
 	}
-	if (p->transport->open(p->name, &p->fda, p->timestamping))
+	if (transport_open(p->trp, p->name, &p->fda, p->timestamping))
 		goto no_tropen;
 
 	for (i = 0; i < N_TIMER_FDS; i++) {
@@ -546,7 +546,7 @@ static int port_initialize(struct port *p)
 	return 0;
 
 no_tmo:
-	p->transport->close(&p->fda);
+	transport_close(p->trp, &p->fda);
 no_tropen:
 no_timers:
 	for (i = 0; i < N_TIMER_FDS; i++) {
@@ -646,7 +646,7 @@ static int process_delay_req(struct port *p, struct ptp_message *m)
 		err = -1;
 		goto out;
 	}
-	cnt = p->transport->send(&p->fda, 0, msg, pdulen, NULL);
+	cnt = transport_send(p->trp, &p->fda, 0, msg, pdulen, NULL);
 	if (cnt <= 0) {
 		pr_err("port %hu: send delay response failed", portnum(p));
 		err = -1;
@@ -782,7 +782,8 @@ static void process_sync(struct port *p, struct ptp_message *m)
 void port_close(struct port *p)
 {
 	int i;
-	p->transport->close(&p->fda);
+	transport_close(p->trp, &p->fda);
+	transport_destroy(p->trp);
 	for (i = 0; i < N_TIMER_FDS; i++) {
 		close(p->fda.fd[FD_ANNOUNCE_TIMER + i]);
 	}
@@ -915,7 +916,7 @@ enum fsm_event port_event(struct port *p, int fd_index)
 
 	msg->hwts.type = p->timestamping;
 
-	cnt = p->transport->recv(fd, msg, sizeof(*msg), &msg->hwts);
+	cnt = transport_recv(p->trp, fd, msg, sizeof(*msg), &msg->hwts);
 	if (cnt <= 0) {
 		pr_err("port %hu: recv message failed", portnum(p));
 		msg_put(msg);
@@ -979,8 +980,8 @@ struct port *port_open(struct port_defaults *pod,
 	p->pod = *pod;
 	p->name = name;
 	p->clock = clock;
-	p->transport = transport_find(transport);
+	p->trp = transport_create(transport);
-	if (!p->transport) {
+	if (!p->trp) {
 		free(p);
 		return NULL;
 	}

transport.c

@@ -18,20 +18,37 @@
  */
 
 #include "transport.h"
+#include "transport_private.h"
 #include "udp.h"
 
-static struct transport udp = {
+int transport_close(struct transport *t, struct fdarray *fda)
-	.close = udp_close,
+{
-	.open  = udp_open,
+	return t->close(t, fda);
-	.recv  = udp_recv,
+}
-	.send  = udp_send,
-};
 
-struct transport *transport_find(enum transport_type type)
+int transport_open(struct transport *t, char *name,
+		   struct fdarray *fda, enum timestamp_type tt)
+{
+	return t->open(t, name, fda, tt);
+}
+
+int transport_recv(struct transport *t, int fd,
+		   void *buf, int buflen, struct hw_timestamp *hwts)
+{
+	return t->recv(t, fd, buf, buflen, hwts);
+}
+
+int transport_send(struct transport *t, struct fdarray *fda, int event,
+		   void *buf, int buflen, struct hw_timestamp *hwts)
+{
+	return t->send(t, fda, event, buf, buflen, hwts);
+}
+
+struct transport *transport_create(enum transport_type type)
 {
 	switch (type) {
 	case TRANS_UDP_IPV4:
-		return &udp;
+		return udp_transport_create();
 	case TRANS_UDP_IPV6:
 	case TRANS_IEEE_802_3:
 	case TRANS_DEVICENET:
@@ -41,3 +58,8 @@ struct transport *transport_find(enum transport_type type)
 	}
 	return NULL;
 }
+
+void transport_destroy(struct transport *t)
+{
+	t->release(t);
+}

transport.h

@@ -44,19 +44,30 @@ struct hw_timestamp {
 	struct timespec ts;
 };
 
-struct transport {
+struct transport;
-	int (*close)(struct fdarray *fda);
+
-	int (*open)(char *name, struct fdarray *fda, enum timestamp_type tt);
+int transport_close(struct transport *t, struct fdarray *fda);
-	int (*recv)(int fd, void *buf, int buflen, struct hw_timestamp *hwts);
+
-	int (*send)(struct fdarray *fda, int event,
+int transport_open(struct transport *t, char *name,
-		    void *buf, int buflen, struct hw_timestamp *hwts);
+		   struct fdarray *fda, enum timestamp_type tt);
-};
+
+int transport_recv(struct transport *t, int fd,
+		   void *buf, int buflen, struct hw_timestamp *hwts);
+
+int transport_send(struct transport *t, struct fdarray *fda, int event,
+		   void *buf, int buflen, struct hw_timestamp *hwts);
 
 /**
- * Obtain a pointer to the specified transport.
+ * Allocate an instance of the specified transport.
  * @param type  Which transport to obtain.
- * @return      Pointer to a static global.
+ * @return      Pointer to a transport instance on success, NULL otherwise.
  */
-struct transport *transport_find(enum transport_type type);
+struct transport *transport_create(enum transport_type type);
+
+/**
+ * Free an instance of a transport.
+ * @param t Pointer obtained by calling transport_create().
+ */
+void transport_destroy(struct transport *t);
 
 #endif

transport_private.h

@@ -0,0 +1,43 @@
+/**
+ * @file transport_private.h
+ * @brief Defines a private interface for the abstract transport layer.
+ * @note Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef HAVE_TRANSPORT_PRIVATE_H
+#define HAVE_TRANSPORT_PRIVATE_H
+
+#include <time.h>
+
+#include "fd.h"
+#include "transport.h"
+
+struct transport {
+	int (*close)(struct transport *t, struct fdarray *fda);
+
+	int (*open)(struct transport *t, char *name, struct fdarray *fda,
+		    enum timestamp_type tt);
+
+	int (*recv)(struct transport *t, int fd, void *buf, int buflen,
+		    struct hw_timestamp *hwts);
+
+	int (*send)(struct transport *t, struct fdarray *fda, int event,
+		    void *buf, int buflen, struct hw_timestamp *hwts);
+
+	void (*release)(struct transport *t);
+};
+
+#endif

udp.c

@@ -33,6 +33,7 @@
 #include <linux/sockios.h>
 
 #include "print.h"
+#include "transport_private.h"
 #include "udp.h"
 
 #define EVENT_PORT        319
@@ -162,7 +163,7 @@ static int mcast_join(int fd, int index, const struct sockaddr *grp,
 	return 0;
 }
 
-int udp_close(struct fdarray *fda)
+static int udp_close(struct transport *t, struct fdarray *fda)
 {
 	close(fda->fd[0]);
 	close(fda->fd[1]);
@@ -216,7 +217,8 @@ no_socket:
 
 static struct in_addr mc_addr;
 
-int udp_open(char *name, struct fdarray *fda, enum timestamp_type ts_type)
+static int udp_open(struct transport *t, char *name, struct fdarray *fda,
+		    enum timestamp_type ts_type)
 {
 	int efd, gfd;
 
@@ -316,13 +318,14 @@ static int receive(int fd, void *buf, int buflen,
 	return cnt;
 }
 
-int udp_recv(int fd, void *buf, int buflen, struct hw_timestamp *hwts)
+static int udp_recv(struct transport *t, int fd, void *buf, int buflen,
+		    struct hw_timestamp *hwts)
 {
 	return receive(fd, buf, buflen, hwts, 0);
 }
 
-int udp_send(struct fdarray *fda, int event,
+static int udp_send(struct transport *t, struct fdarray *fda, int event,
-	     void *buf, int len, struct hw_timestamp *hwts)
+		    void *buf, int len, struct hw_timestamp *hwts)
 {
 	ssize_t cnt;
 	int fd = event ? fda->fd[FD_EVENT] : fda->fd[FD_GENERAL];
@@ -344,6 +347,24 @@ int udp_send(struct fdarray *fda, int event,
 	return event ? receive(fd, junk, len, hwts, MSG_ERRQUEUE) : cnt;
 }
 
+static struct transport the_udp_transport = {
+	.close = udp_close,
+	.open  = udp_open,
+	.recv  = udp_recv,
+	.send  = udp_send,
+};
+
+struct transport *udp_transport_create(void)
+{
+	/* No need for any per-instance allocation. */
+	return &the_udp_transport;
+}
+
+void udp_transport_destroy(struct transport *t)
+{
+	/* No need for any per-instance deallocation. */
+}
+
 int udp_interface_macaddr(char *name, unsigned char *mac, int len)
 {
 	struct ifreq ifreq;

udp.h

@@ -23,12 +23,6 @@
 #include "fd.h"
 #include "transport.h"
 
-int udp_close(struct fdarray *fda);
-int udp_open(char *name, struct fdarray *fda, enum timestamp_type ts_type);
-int udp_recv(int fd, void *buf, int buflen, struct hw_timestamp *hwts);
-int udp_send(struct fdarray *fda, int event,
-	     void *buf, int buflen, struct hw_timestamp *hwts);
-
 /**
  * Obtain the MAC address of a network interface.
  * @param name  The name of the interface
@@ -38,4 +32,16 @@ int udp_send(struct fdarray *fda, int event,
  */
 int udp_interface_macaddr(char *name, unsigned char *mac, int len);
 
+/**
+ * Allocate an instance of a UDP/IPv4 transport.
+ * @return Pointer to a new transport instance on success, NULL otherwise.
+ */
+struct transport *udp_transport_create(void);
+
+/**
+ * Free an instance of a UDP/IPv4 transport.
+ * @param t Pointer obtained by calling udp_transport_create().
+ */
+void udp_transport_destroy(struct transport *t);
+
 #endif