From 0fe6ba7fbca6d7f4da99208b41ec2a6444ca7d15 Mon Sep 17 00:00:00 2001
From: Henry Wong <v4l@stuffedcow.net>
Date: Sun, 18 Sep 2011 13:41:49 +0000
Subject: [PATCH] --- yaml --- r: 264058 b: refs/heads/master c:
 22e83a2926998fe132ae4dd26f1e998c70ae2e38 h: refs/heads/master v: v3

---
 [refs]                          | 2 +-
 trunk/drivers/net/ppp_generic.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 201edd89450f..d923a7d186f5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d706f00f65146822c0097b796b3557ea8980c305
+refs/heads/master: 22e83a2926998fe132ae4dd26f1e998c70ae2e38
diff --git a/trunk/drivers/net/ppp_generic.c b/trunk/drivers/net/ppp_generic.c
index 10e5d985afa3..edfa15d2e795 100644
--- a/trunk/drivers/net/ppp_generic.c
+++ b/trunk/drivers/net/ppp_generic.c
@@ -1465,7 +1465,12 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
 			continue;
 		}
 
-		mtu = pch->chan->mtu - hdrlen;
+		/*
+		 * hdrlen includes the 2-byte PPP protocol field, but the
+		 * MTU counts only the payload excluding the protocol field.
+		 * (RFC1661 Section 2)
+		 */
+		mtu = pch->chan->mtu - (hdrlen - 2);
 		if (mtu < 4)
 			mtu = 4;
 		if (flen > mtu)