1 files changed, 128 insertions, 0 deletions
diff --git a/src/openvpn/proto.c b/src/openvpn/proto.c
new file mode 100644
index 0000000..2cf8314
--- /dev/null
+++ b/src/openvpn/proto.c
@@ -0,0 +1,128 @@
+/*
+ *  OpenVPN -- An application to securely tunnel IP networks
+ *             over a single TCP/UDP port, with support for SSL/TLS-based
+ *             session authentication and key exchange,
+ *             packet encryption, packet authentication, and
+ *             packet compression.
+ *
+ *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program (see the file COPYING included with this
+ *  distribution); if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#include "proto.h"
+#include "error.h"
+
+#include "memdbg.h"
+
+/*
+ * If raw tunnel packet is IPv4, return true and increment
+ * buffer offset to start of IP header.
+ */
+bool
+is_ipv4 (int tunnel_type, struct buffer *buf)
+{
+  int offset;
+  const struct openvpn_iphdr *ih;
+
+  verify_align_4 (buf);
+  if (tunnel_type == DEV_TYPE_TUN)
+    {
+      if (BLEN (buf) < (int) sizeof (struct openvpn_iphdr))
+	return false;
+      offset = 0;
+    }
+  else if (tunnel_type == DEV_TYPE_TAP)
+    {
+      const struct openvpn_ethhdr *eh;
+      if (BLEN (buf) < (int)(sizeof (struct openvpn_ethhdr)
+	  + sizeof (struct openvpn_iphdr)))
+	return false;
+      eh = (const struct openvpn_ethhdr *) BPTR (buf);
+      if (ntohs (eh->proto) != OPENVPN_ETH_P_IPV4)
+	return false;
+      offset = sizeof (struct openvpn_ethhdr);
+    }
+  else
+    return false;
+
+  ih = (const struct openvpn_iphdr *) (BPTR (buf) + offset);
+
+  if (OPENVPN_IPH_GET_VER (ih->version_len) == 4)
+    return buf_advance (buf, offset);
+  else
+    return false;
+}
+
+#ifdef PACKET_TRUNCATION_CHECK
+
+void
+ipv4_packet_size_verify (const uint8_t *data,
+			 const int size,
+			 const int tunnel_type,
+			 const char *prefix,
+			 counter_type *errors)
+{
+  if (size > 0)
+    {
+      struct buffer buf;
+
+      buf_set_read (&buf, data, size);
+
+      if (is_ipv4 (tunnel_type, &buf))
+	{
+	  const struct openvpn_iphdr *pip;
+	  int hlen;
+	  int totlen;
+	  const char *msgstr = "PACKET SIZE INFO";
+	  unsigned int msglevel = D_PACKET_TRUNC_DEBUG;
+
+	  if (BLEN (&buf) < (int) sizeof (struct openvpn_iphdr))
+	    return;
+  
+	  verify_align_4 (&buf);
+	  pip = (struct openvpn_iphdr *) BPTR (&buf);
+	  
+	  hlen = OPENVPN_IPH_GET_LEN (pip->version_len);
+	  totlen = ntohs (pip->tot_len);
+	  
+	  if (BLEN (&buf) != totlen)
+	    {
+	      msgstr = "PACKET TRUNCATION ERROR";
+	      msglevel = D_PACKET_TRUNC_ERR;
+	      if (errors)
+		++(*errors);
+	    }
+
+	  msg (msglevel, "%s %s: size=%d totlen=%d hlen=%d errcount=" counter_format,
+	       msgstr,
+	       prefix,
+	       BLEN (&buf),
+	       totlen,
+	       hlen,
+	       errors ? *errors : (counter_type)0);
+	}
+    }
+}
+
+#endif