From 285b88ade4b3c6236966670e5898a4d344dc6559 Mon Sep 17 00:00:00 2001
From: Richard Cochran <richardcochran@gmail.com>
Date: Sun, 27 Jan 2013 16:23:11 +0100
Subject: [PATCH] Let a port become 'capable' according to 802.1AS.

This patch implements the capable flag as follows.

1. After calculating the neighbor rate, we are capable.
2. If we miss too many responses, we are incapable.
3. If we get multiple responses, we throw a fault,
   and so we are also incapable.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
---
 port.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/port.c b/port.c
index 4d6b8da..036a53b 100644
--- a/port.c
+++ b/port.c
@@ -515,6 +515,11 @@ static void port_nrate_calculate(struct port *p, tmv_t t3, tmv_t t4, tmv_t c)
 	n->ingress1 = t4;
 	n->origin1 = origin2;
 	n->count = 0;
+	/*
+	 * We experienced a successful series of exchanges of peer
+	 * delay request and response, and so the port is now capable.
+	 */
+	p->pdr_missing = 0;
 }
 
 static void port_nrate_initialize(struct port *p)
@@ -650,9 +655,12 @@ static int port_pdelay_request(struct port *p)
 		goto out;
 	}
 
-	if (p->peer_delay_req)
+	if (p->peer_delay_req) {
+		if (port_capable(p)) {
+			p->pdr_missing++;
+		}
 		msg_put(p->peer_delay_req);
-
+	}
 	p->peer_delay_req = msg;
 	return 0;
 out:
@@ -1324,22 +1332,27 @@ calc:
 	if (p->state == PS_UNCALIBRATED || p->state == PS_SLAVE) {
 		clock_peer_delay(p->clock, p->peer_delay, p->nrate.ratio);
 	}
+
+	msg_put(p->peer_delay_req);
+	p->peer_delay_req = NULL;
 }
 
 static int process_pdelay_resp(struct port *p, struct ptp_message *m)
 {
-	if (!p->peer_delay_req) {
-		pr_err("port %hu: rogue peer delay response", portnum(p));
-		return -1;
-	}
 	if (p->peer_delay_resp) {
 		if (!source_pid_eq(p->peer_delay_resp, m)) {
 			pr_err("port %hu: multiple peer responses", portnum(p));
 			return -1;
 		}
-		msg_put(p->peer_delay_resp);
+	}
+	if (!p->peer_delay_req) {
+		pr_err("port %hu: rogue peer delay response", portnum(p));
+		return -1;
 	}
 
+	if (p->peer_delay_resp) {
+		msg_put(p->peer_delay_resp);
+	}
 	msg_get(m);
 	p->peer_delay_resp = m;
 	port_peer_delay(p);