e2e_tc: Implement an end to end transparent clock.

The E2E TC forwards Announce, Delay_Req, Delay_Resp, Management,
Signaling, and Sync messages, and drops P2P Delay messages.

This implementation tracks the GM using the BMCA in order
to syntonize (or possibly even synchronize) with it.

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

clock.c

@@ -875,9 +875,9 @@ struct clock *clock_create(enum clock_type type, struct config *config,
 	case CLOCK_TYPE_ORDINARY:
 	case CLOCK_TYPE_BOUNDARY:
 	case CLOCK_TYPE_P2P:
+	case CLOCK_TYPE_E2E:
 		c->type = type;
 		break;
-	case CLOCK_TYPE_E2E:
 	case CLOCK_TYPE_MANAGEMENT:
 		return NULL;
 	}

e2e_tc.c

@@ -0,0 +1,226 @@
+/**
+ * @file e2e_tc.c
+ * @note Copyright (C) 2018 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 02110-1335 USA.
+ */
+#include <errno.h>
+
+#include "port.h"
+#include "port_private.h"
+#include "print.h"
+#include "rtnl.h"
+#include "tc.h"
+
+void e2e_dispatch(struct port *p, enum fsm_event event, int mdiff)
+{
+	if (!port_state_update(p, event, mdiff)) {
+		return;
+	}
+	if (!portnum(p)) {
+		/* UDS needs no timers. */
+		return;
+	}
+
+	port_clr_tmo(p->fda.fd[FD_ANNOUNCE_TIMER]);
+	port_clr_tmo(p->fda.fd[FD_SYNC_RX_TIMER]);
+	/* Leave FD_DELAY_TIMER running. */
+	port_clr_tmo(p->fda.fd[FD_QUALIFICATION_TIMER]);
+	port_clr_tmo(p->fda.fd[FD_MANNO_TIMER]);
+	port_clr_tmo(p->fda.fd[FD_SYNC_TX_TIMER]);
+
+	/*
+	 * Handle the side effects of the state transition.
+	 */
+	switch (p->state) {
+	case PS_INITIALIZING:
+		break;
+	case PS_FAULTY:
+	case PS_DISABLED:
+		port_disable(p);
+		break;
+	case PS_LISTENING:
+		port_set_announce_tmo(p);
+		port_set_delay_tmo(p);
+		break;
+	case PS_PRE_MASTER:
+		port_set_qualification_tmo(p);
+		break;
+	case PS_MASTER:
+	case PS_GRAND_MASTER:
+		break;
+	case PS_PASSIVE:
+		port_set_announce_tmo(p);
+		break;
+	case PS_UNCALIBRATED:
+		flush_last_sync(p);
+		flush_delay_req(p);
+		/* fall through */
+	case PS_SLAVE:
+		port_set_announce_tmo(p);
+		break;
+	};
+}
+
+enum fsm_event e2e_event(struct port *p, int fd_index)
+{
+	int cnt, fd = p->fda.fd[fd_index];
+	enum fsm_event event = EV_NONE;
+	struct ptp_message *msg, *dup;
+
+	switch (fd_index) {
+	case FD_ANNOUNCE_TIMER:
+	case FD_SYNC_RX_TIMER:
+		pr_debug("port %hu: %s timeout", portnum(p),
+			 fd_index == FD_SYNC_RX_TIMER ? "rx sync" : "announce");
+		if (p->best) {
+			fc_clear(p->best);
+		}
+		port_set_announce_tmo(p);
+		return EV_ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES;
+
+	case FD_DELAY_TIMER:
+		pr_debug("port %hu: delay timeout", portnum(p));
+		port_set_delay_tmo(p);
+		delay_req_prune(p);
+		tc_prune(p);
+		if (!clock_free_running(p->clock)) {
+			switch (p->state) {
+			case PS_UNCALIBRATED:
+			case PS_SLAVE:
+				if (port_delay_request(p)) {
+					event = EV_FAULT_DETECTED;
+				}
+				break;
+			default:
+				break;
+			};
+		}
+		return event;
+
+	case FD_QUALIFICATION_TIMER:
+		pr_debug("port %hu: qualification timeout", portnum(p));
+		return EV_QUALIFICATION_TIMEOUT_EXPIRES;
+
+	case FD_MANNO_TIMER:
+	case FD_SYNC_TX_TIMER:
+		pr_err("unexpected timer expiration");
+		return EV_NONE;
+
+	case FD_RTNL:
+		pr_debug("port %hu: received link status notification", portnum(p));
+		rtnl_link_status(fd, p->name, port_link_status, p);
+		if (p->link_status == (LINK_UP|LINK_STATE_CHANGED)) {
+			return EV_FAULT_CLEARED;
+		} else if ((p->link_status == (LINK_DOWN|LINK_STATE_CHANGED)) ||
+			   (p->link_status & TS_LABEL_CHANGED)) {
+			return EV_FAULT_DETECTED;
+		} else {
+			return EV_NONE;
+		}
+	}
+
+	msg = msg_allocate();
+	if (!msg) {
+		return EV_FAULT_DETECTED;
+	}
+	msg->hwts.type = p->timestamping;
+
+	cnt = transport_recv(p->trp, fd, msg);
+	if (cnt <= 0) {
+		pr_err("port %hu: recv message failed", portnum(p));
+		msg_put(msg);
+		return EV_FAULT_DETECTED;
+	}
+	if (msg_sots_valid(msg)) {
+		ts_add(&msg->hwts.ts, -p->rx_timestamp_offset);
+	}
+	if (msg->header.flagField[0] & UNICAST) {
+		pl_warning(600, "cannot handle unicast messages!");
+		msg_put(msg);
+		return EV_NONE;
+	}
+
+	dup = msg_duplicate(msg, cnt);
+	if (!dup) {
+		msg_put(msg);
+		return EV_NONE;
+	}
+	if (tc_ignore(p, dup)) {
+		msg_put(dup);
+		dup = NULL;
+	}
+
+	switch (msg_type(msg)) {
+	case SYNC:
+		if (tc_fwd_sync(p, msg)) {
+			event = EV_FAULT_DETECTED;
+			break;
+		}
+		if (dup) {
+			process_sync(p, dup);
+		}
+		break;
+	case DELAY_REQ:
+		if (tc_fwd_request(p, msg)) {
+			event = EV_FAULT_DETECTED;
+		}
+		break;
+	case PDELAY_REQ:
+		break;
+	case PDELAY_RESP:
+		break;
+	case FOLLOW_UP:
+		if (tc_fwd_folup(p, msg)) {
+			event = EV_FAULT_DETECTED;
+			break;
+		}
+		if (dup) {
+			process_follow_up(p, dup);
+		}
+		break;
+	case DELAY_RESP:
+		if (tc_fwd_response(p, msg)) {
+			event = EV_FAULT_DETECTED;
+		}
+		if (dup) {
+			process_delay_resp(p, dup);
+		}
+		break;
+	case PDELAY_RESP_FOLLOW_UP:
+		break;
+	case ANNOUNCE:
+		if (tc_forward(p, msg)) {
+			event = EV_FAULT_DETECTED;
+			break;
+		}
+		if (dup && process_announce(p, dup)) {
+			event = EV_STATE_DECISION_EVENT;
+		}
+		break;
+	case SIGNALING:
+	case MANAGEMENT:
+		if (tc_forward(p, msg)) {
+			event = EV_FAULT_DETECTED;
+		}
+		break;
+	}
+
+	msg_put(msg);
+	if (dup) {
+		msg_put(dup);
+	}
+	return event;
+}

makefile

@@ -23,7 +23,7 @@ VER     = -DVER=$(version)
 CFLAGS	= -Wall $(VER) $(incdefs) $(DEBUG) $(EXTRA_CFLAGS)
 LDLIBS	= -lm -lrt $(EXTRA_LDFLAGS)
 PRG	= ptp4l hwstamp_ctl nsm phc2sys phc_ctl pmc timemaster
-OBJ     = bmc.o clock.o clockadj.o clockcheck.o config.o fault.o \
+OBJ     = bmc.o clock.o clockadj.o clockcheck.o config.o e2e_tc.o fault.o \
  filter.o fsm.o hash.o linreg.o mave.o mmedian.o msg.o ntpshm.o nullf.o phc.o \
  pi.o port.o print.o ptp4l.o p2p_tc.o raw.o rtnl.o servo.o sk.o stats.o tc.o \
  telecom.o tlv.o transport.o tsproc.o udp.o udp6.o uds.o util.o version.o

port.c

@@ -2792,6 +2792,9 @@ struct port *port_open(int phc_index,
 		p->event = p2p_event;
 		break;
 	case CLOCK_TYPE_E2E:
+		p->dispatch = e2e_dispatch;
+		p->event = e2e_event;
+		break;
 	case CLOCK_TYPE_MANAGEMENT:
 		return NULL;
 	}
@@ -2848,6 +2851,10 @@ struct port *port_open(int phc_index,
 		pr_err("port %d: P2P TC needs P2P ports", number);
 		goto err_port;
 	}
+	if (number && type == CLOCK_TYPE_E2E && p->delayMechanism != DM_E2E) {
+		pr_err("port %d: E2E TC needs E2E ports", number);
+		goto err_port;
+	}
 	if (p->hybrid_e2e && p->delayMechanism != DM_E2E) {
 		pr_warning("port %d: hybrid_e2e only works with E2E", number);
 	}

port_private.h

@@ -135,6 +135,9 @@ struct port {
 
 #define portnum(p) (p->portIdentity.portNumber)
 
+void e2e_dispatch(struct port *p, enum fsm_event event, int mdiff);
+enum fsm_event e2e_event(struct port *p, int fd_index);
+
 void p2p_dispatch(struct port *p, enum fsm_event event, int mdiff);
 enum fsm_event p2p_event(struct port *p, int fd_index);