Allow bigger D-Bus packets, but don't allocate big buffers initially.

D-Bus packets can be up to 128MB in size, but don't allocate 128MB for
every pcap_t, or even every D-Bus pcap_t.  Start out with enough to
handle 2KB packets - that should be enough for most regular network
packets - and grow the buffer as necessary to handle packets up to the
snapshot length.

Treat packets bigger than the maximum snapshot length for the link-layer
type as errors; we continue to use MAXIMUM_SNAPLEN (256KB) for most
link-layer header types, but use 128MB for DLT_DBUS, as per the above.

If the snapshot length in the file header or IDB is 0, or is > 2^31-1,
use the maximum snapshot length for the link-layer header type as the
snapshot length.  The check for 2^31-1 is there because the current API
for snapshot lengths returns an int, and thus can't handle snapshot
lengths > 2^31-1, even though the field is actually unsigned.

1 files changed, 24 insertions, 0 deletions

diff --git a/pcap-common.h b/pcap-common.h
index 6ac5bcd2..b8d1f314 100644
--- a/pcap-common.h
+++ b/pcap-common.h
@@ -1,3 +1,25 @@
+/*
+ * Copyright (c) 1993, 1994, 1995, 1996, 1997
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * pcap-common.h - common code for pcap and pcap-ng files
+ */
 
 /*
  * We use the "receiver-makes-right" approach to byte order,
@@ -23,3 +45,5 @@ extern int linktype_to_dlt(int linktype);
 
 extern void swap_pseudo_headers(int linktype, struct pcap_pkthdr *hdr,
     u_char *data);
+
+extern u_int max_snaplen_for_dlt(int dlt);