From ff44e305b138f33a224d2672bc0a45d39018b928 Mon Sep 17 00:00:00 2001
From: Richard Cochran <richardcochran@gmail.com>
Date: Sun, 3 Jun 2012 19:56:56 +0200
Subject: [PATCH] Refactor the post receive method to check the length first.

This patch is in preparation for handling the suffix TLV data. We will
need to use the structure size more than once.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
---
 msg.c | 58 +++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 39 insertions(+), 19 deletions(-)

diff --git a/msg.c b/msg.c
index ce04fce..c26c3e0 100644
--- a/msg.c
+++ b/msg.c
@@ -162,7 +162,7 @@ void msg_get(struct ptp_message *m)
 
 int msg_post_recv(struct ptp_message *m, int cnt)
 {
-	int type;
+	int pdulen, type;
 
 	if (cnt < sizeof(struct ptp_header))
 		return -1;
@@ -174,43 +174,65 @@ int msg_post_recv(struct ptp_message *m, int cnt)
 
 	switch (type) {
 	case SYNC:
-		if (cnt < sizeof(struct sync_msg))
-			return -1;
+		pdulen = sizeof(struct sync_msg);
+		break;
+	case DELAY_REQ:
+		pdulen = sizeof(struct delay_req_msg);
+		break;
+	case PDELAY_REQ:
+		pdulen = sizeof(struct pdelay_req_msg);
+		break;
+	case PDELAY_RESP:
+		pdulen = sizeof(struct pdelay_resp_msg);
+		break;
+	case FOLLOW_UP:
+		pdulen = sizeof(struct follow_up_msg);
+		break;
+	case DELAY_RESP:
+		pdulen = sizeof(struct delay_resp_msg);
+		break;
+	case PDELAY_RESP_FOLLOW_UP:
+		pdulen = sizeof(struct pdelay_resp_fup_msg);
+		break;
+	case ANNOUNCE:
+		pdulen = sizeof(struct announce_msg);
+		break;
+	case SIGNALING:
+		pdulen = sizeof(struct signaling_msg);
+		break;
+	case MANAGEMENT:
+		pdulen = sizeof(struct management_msg);
+		break;
+	default:
+		return -1;
+	}
+
+	if (cnt < pdulen)
+		return -1;
+
+	switch (type) {
+	case SYNC:
 		timestamp_post_recv(m, &m->sync.originTimestamp);
 		break;
 	case DELAY_REQ:
-		if (cnt < sizeof(struct delay_req_msg))
-			return -1;
 		break;
 	case PDELAY_REQ:
-		if (cnt < sizeof(struct pdelay_req_msg))
-			return -1;
 		break;
 	case PDELAY_RESP:
-		if (cnt < sizeof(struct pdelay_resp_msg))
-			return -1;
 		timestamp_post_recv(m, &m->pdelay_resp.requestReceiptTimestamp);
 		port_id_post_recv(&m->pdelay_resp.requestingPortIdentity);
 		break;
 	case FOLLOW_UP:
-		if (cnt < sizeof(struct follow_up_msg))
-			return -1;
 		timestamp_post_recv(m, &m->follow_up.preciseOriginTimestamp);
 		break;
 	case DELAY_RESP:
-		if (cnt < sizeof(struct delay_resp_msg))
-			return -1;
 		timestamp_post_recv(m, &m->delay_resp.receiveTimestamp);
 		break;
 	case PDELAY_RESP_FOLLOW_UP:
-		if (cnt < sizeof(struct pdelay_resp_fup_msg))
-			return -1;
 		timestamp_post_recv(m, &m->pdelay_resp_fup.responseOriginTimestamp);
 		port_id_post_recv(&m->pdelay_resp_fup.requestingPortIdentity);
 		break;
 	case ANNOUNCE:
-		if (cnt < sizeof(struct announce_msg))
-			return -1;
 		clock_gettime(CLOCK_MONOTONIC, &m->ts.host);
 		timestamp_post_recv(m, &m->announce.originTimestamp);
 		announce_post_recv(&m->announce);
@@ -218,8 +240,6 @@ int msg_post_recv(struct ptp_message *m, int cnt)
 	case SIGNALING:
 	case MANAGEMENT:
 		break;
-	default:
-		return -1;
 	}
 
 	if (msg_sots_missing(m)) {