From 8697599b2b01aac0886db1a19f0c407f4dfc3a3e Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Sun, 15 Mar 2009 17:40:24 +0800
Subject: [PATCH] Add M_LENCHECKED mbuf flag.

This flag indicates that various protocol length fields of the packet
are checked.  It is only used by IPv4 currently (ip_lengthcheck()).
---
 sys/net/if_ethersubr.c | 6 +++++-
 sys/netinet/ip_demux.c | 1 +
 sys/sys/mbuf.h         | 4 +++-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 33628f208d..9a7429987b 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -72,7 +72,7 @@
 
 #if defined(INET) || defined(INET6)
 #include <netinet/in.h>
-#include <netinet/in_var.h>
+#include <netinet/ip_var.h>
 #include <netinet/if_ether.h>
 #include <netinet/ip_flow.h>
 #include <net/ipfw/ip_fw.h>
@@ -1176,6 +1176,10 @@ post_stats:
 	switch (ether_type) {
 #ifdef INET
 	case ETHERTYPE_IP:
+		if ((m->m_flags & M_LENCHECKED) == 0) {
+			if (!ip_lengthcheck(&m))
+				return;
+		}
 		if (ipflow_fastforward(m))
 			return;
 		isr = NETISR_IP;
diff --git a/sys/netinet/ip_demux.c b/sys/netinet/ip_demux.c
index ab8ccac61e..33f9ab995e 100644
--- a/sys/netinet/ip_demux.c
+++ b/sys/netinet/ip_demux.c
@@ -254,6 +254,7 @@ ipcheckonly:
 		break;
 	}
 
+	m->m_flags |= M_LENCHECKED;
 	*mp = m;
 	return TRUE;
 
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index dae8b5a94f..eef99fab19 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -206,13 +206,15 @@ struct mbuf {
 #define M_NOTIFICATION	0x10000	/* notification event */
 #define M_VLANTAG	0x20000	/* ether_vlantag is valid */
 #define M_MPLSLABELED	0x40000	/* packet is mpls labeled */
+#define M_LENCHECKED	0x80000	/* packet proto lengths are checked */
 
 /*
  * Flags copied when copying m_pkthdr.
  */
 #define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_PROTO1|M_PROTO2|M_PROTO3 | \
 			 M_PROTO4|M_PROTO5|M_BCAST|M_MCAST|M_FRAG | \
-			 M_FIRSTFRAG|M_LASTFRAG|M_VLANTAG|M_MPLSLABELED)
+			 M_FIRSTFRAG|M_LASTFRAG|M_VLANTAG|M_MPLSLABELED | \
+			 M_LENCHECKED)
 
 /*
  * Flags indicating hw checksum support and sw checksum requirements.
-- 
2.41.0