From 5f82a10ea30cc17bd16ac17e9b18725cc5ab5135 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 7 Oct 2011 05:45:57 +0000
Subject: [PATCH] --- yaml --- r: 266839 b: refs/heads/master c:
 09df57ca604512b29b6096afb381c839ccbd2912 h: refs/heads/master i:   266837:
 d4e76b58ef6fad4fe81c2c92146a8ff02c2459d9   266835:
 41dbfab7724c3aa40c465ae8d258d306f1a56f83   266831:
 40f522b35bb4ef08f60078535c9a8b5e356bc0b1 v: v3

---
 [refs]                    | 2 +-
 trunk/net/l2tp/l2tp_ppp.c | 9 ++++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 07ddaff1f9ab..63e1fbe76015 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bc416d9768aa9a2e46eb11354a9c58399dafeb01
+refs/heads/master: 09df57ca604512b29b6096afb381c839ccbd2912
diff --git a/trunk/net/l2tp/l2tp_ppp.c b/trunk/net/l2tp/l2tp_ppp.c
index f42cd0915966..8a90d756c904 100644
--- a/trunk/net/l2tp/l2tp_ppp.c
+++ b/trunk/net/l2tp/l2tp_ppp.c
@@ -395,6 +395,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 	struct pppol2tp_session *ps;
 	int old_headroom;
 	int new_headroom;
+	int uhlen, headroom;
 
 	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 		goto abort;
@@ -413,7 +414,13 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 		goto abort_put_sess;
 
 	old_headroom = skb_headroom(skb);
-	if (skb_cow_head(skb, sizeof(ppph)))
+	uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
+	headroom = NET_SKB_PAD +
+		   sizeof(struct iphdr) + /* IP header */
+		   uhlen +		/* UDP header (if L2TP_ENCAPTYPE_UDP) */
+		   session->hdr_len +	/* L2TP header */
+		   sizeof(ppph);	/* PPP header */
+	if (skb_cow_head(skb, headroom))
 		goto abort_put_sess_tun;
 
 	new_headroom = skb_headroom(skb);