diff --git a/libpcap/NMAP_MODIFICATIONS/0001-Don-t-autogenerate-Lex-Yacc-files.patch b/libpcap/NMAP_MODIFICATIONS/0001-Don-t-autogenerate-Lex-Yacc-files.patch
new file mode 100644
index 000000000..eaefb37e8
--- /dev/null
+++ b/libpcap/NMAP_MODIFICATIONS/0001-Don-t-autogenerate-Lex-Yacc-files.patch
@@ -0,0 +1,123 @@
+From c0ccc9cd933823a642b1ccfa4c78fea1b672e731 Mon Sep 17 00:00:00 2001
+From: David Fifield <david@bamsoftware.com>
+Date: Mon, 9 Apr 2012 16:55:51 -0700
+Subject: [PATCH 1/4] Don't autogenerate Lex/Yacc files.
+
+---
+ Makefile.in  |   30 ++++++++++--------------------
+ configure.in |   20 --------------------
+ 2 files changed, 10 insertions(+), 40 deletions(-)
+
+diff --git Makefile.in Makefile.in
+index 912b7e3..0db12a4 100644
+--- Makefile.in
++++ Makefile.in
+@@ -67,14 +67,6 @@ INSTALL_PROGRAM = @INSTALL_PROGRAM@
+ INSTALL_DATA = @INSTALL_DATA@
+ RANLIB = @RANLIB@
+ 
+-#
+-# Flex and bison allow you to specify the prefixes of the global symbols
+-# used by the generated parser.  This allows programs to use lex/yacc
+-# and link against libpcap.  If you don't have flex or bison, get them.
+-#
+-LEX = @V_LEX@
+-YACC = @V_YACC@
+-
+ # Explicitly define compilation rule since SunOS 4's make doesn't like gcc.
+ # Also, gcc does not remove the .o before forking 'as', which can be a
+ # problem if you don't own the file but can write to the directory.
+@@ -147,7 +139,7 @@ TAGFILES = \
+ 	$(SRC) $(HDR)
+ 
+ CLEANFILES = $(OBJ) libpcap.* $(TESTS) \
+-	$(PROG)-`cat $(srcdir)/VERSION`.tar.gz $(GENSRC) $(GENHDR) \
++	$(PROG)-`cat $(srcdir)/VERSION`.tar.gz \
+ 	lex.yy.c pcap-config
+ 
+ MAN1 = pcap-config.1
+@@ -345,6 +337,15 @@ EXTRA_DIST = \
+ 
+ all: libpcap.a shared pcap-config
+ 
++# Inhibit implicit rule Make seems to have for using yacc/lex to
++# recompile new scanner.c/grammar.c -- we ship ones which we want to
++# use instead.
++grammar.c:
++	echo "Not rebuilding grammar.c"
++
++scanner.c:
++	echo "Not rebuilding scanner.c"
++
+ libpcap.a: $(OBJ)
+ 	@rm -f $@
+ 	$(AR) rc $@ $(OBJ) $(ADDLARCHIVEOBJS)
+@@ -428,22 +429,11 @@ libpcap.shareda: $(OBJ)
+ #
+ libpcap.none:
+ 
+-scanner.c: $(srcdir)/scanner.l
+-	@rm -f $@
+-	$(srcdir)/runlex.sh $(LEX) -o$@ $<
+-
+ scanner.o: scanner.c tokdefs.h
+ 	$(CC) $(FULL_CFLAGS) -c scanner.c
+ 
+ pcap.o: version.h
+ 
+-tokdefs.h: grammar.c
+-grammar.c: $(srcdir)/grammar.y
+-	@rm -f grammar.c tokdefs.h
+-	$(YACC) -d $<
+-	mv y.tab.c grammar.c
+-	mv y.tab.h tokdefs.h
+-
+ grammar.o: grammar.c
+ 	@rm -f $@
+ 	$(CC) $(FULL_CFLAGS) -Dyylval=pcap_lval -c grammar.c
+diff --git configure.in configure.in
+index 6a146ca..24097b2 100644
+--- configure.in
++++ configure.in
+@@ -998,24 +998,6 @@ if test "$V_PCAP" = snf -a "$ac_cv_lbl_snf_api" = no; then
+ 	AC_MSG_ERROR(Specifying the capture type as 'snf' requires the Myricom Sniffer API to be present; use --with-snf=DIR)
+ fi
+ 
+-AC_LBL_LEX_AND_YACC(V_LEX, V_YACC, pcap_)
+-if test "$V_LEX" = lex ; then
+-# Some versions of lex can't handle the definitions section of scanner.l .
+-# Try lexing it and complain if it can't deal.
+-	AC_CACHE_CHECK([for capable lex], tcpdump_cv_capable_lex,
+-		if lex -t scanner.l > /dev/null 2>&1; then
+-			tcpdump_cv_capable_lex=yes
+-		else
+-			tcpdump_cv_capable_lex=insufficient
+-		fi)
+-	if test $tcpdump_cv_capable_lex = insufficient ; then
+-		AC_MSG_ERROR([Your operating system's lex is insufficient to compile
+- libpcap.  flex is a lex replacement that has many advantages, including
+- being able to compile libpcap.  For more information, see
+- http://www.gnu.org/software/flex/flex.html .])
+-	fi
+-fi
+-
+ #
+ # Assume, by default, no support for shared libraries and V7/BSD convention
+ # for man pages (file formats in section 5, miscellaneous info in section 7).
+@@ -1250,13 +1232,11 @@ AC_SUBST(V_CCOPT)
+ AC_SUBST(V_DEFS)
+ AC_SUBST(V_FINDALLDEVS)
+ AC_SUBST(V_INCLS)
+-AC_SUBST(V_LEX)
+ AC_SUBST(V_PCAP)
+ AC_SUBST(V_SHLIB_CMD)
+ AC_SUBST(V_SHLIB_OPT)
+ AC_SUBST(V_SONAME_OPT)
+ AC_SUBST(V_RPATH_OPT)
+-AC_SUBST(V_YACC)
+ AC_SUBST(ADDLOBJS)
+ AC_SUBST(ADDLARCHIVEOBJS)
+ AC_SUBST(SSRC)
+-- 
+1.7.9.5
+
diff --git a/libpcap/NMAP_MODIFICATIONS/0002-Move-the-inclusion-of-config.h-to-the-top-of-scanner.patch b/libpcap/NMAP_MODIFICATIONS/0002-Move-the-inclusion-of-config.h-to-the-top-of-scanner.patch
new file mode 100644
index 000000000..697b7300b
--- /dev/null
+++ b/libpcap/NMAP_MODIFICATIONS/0002-Move-the-inclusion-of-config.h-to-the-top-of-scanner.patch
@@ -0,0 +1,39 @@
+From d7f1dc6156f619b81de682a0c89cf47884a798de Mon Sep 17 00:00:00 2001
+From: David Fifield <david@bamsoftware.com>
+Date: Mon, 9 Apr 2012 17:06:04 -0700
+Subject: [PATCH 2/4] Move the inclusion of config.h to the top of scanner.l.
+
+This works around _LARGE_FILES difficulties on AIX.
+---
+ scanner.l |   11 +++++++----
+ 1 file changed, 7 insertions(+), 4 deletions(-)
+
+diff --git scanner.l scanner.l
+index 064e9c8..93d7b97 100644
+--- scanner.l
++++ scanner.l
+@@ -1,3 +1,10 @@
++%top{
++/* Must come first for _LARGE_FILE_API on AIX. */
++#ifdef HAVE_CONFIG_H
++#include "config.h"
++#endif
++}
++
+ %{
+ /*
+  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
+@@ -25,10 +32,6 @@ static const char rcsid[] _U_ =
+     "@(#) $Header: /tcpdump/master/libpcap/scanner.l,v 1.112 2008-02-06 10:21:30 guy Exp $ (LBL)";
+ #endif
+ 
+-#ifdef HAVE_CONFIG_H
+-#include "config.h"
+-#endif
+-
+ #ifdef WIN32
+ #include <pcap-stdinc.h>
+ #else /* WIN32 */
+-- 
+1.7.9.5
+
diff --git a/libpcap/NMAP_MODIFICATIONS/0003-Add-the-disable-packet-ring-configure-option.patch b/libpcap/NMAP_MODIFICATIONS/0003-Add-the-disable-packet-ring-configure-option.patch
new file mode 100644
index 000000000..d1375ec76
--- /dev/null
+++ b/libpcap/NMAP_MODIFICATIONS/0003-Add-the-disable-packet-ring-configure-option.patch
@@ -0,0 +1,73 @@
+From edb5f1e2f1d2a010f2d4a1e421efc7895b9e41c9 Mon Sep 17 00:00:00 2001
+From: David Fifield <david@bamsoftware.com>
+Date: Mon, 9 Apr 2012 17:02:40 -0700
+Subject: [PATCH 3/4] Add the --disable-packet-ring configure option.
+
+This allows the creation of 32-bit binaries that are compatible with
+64-bit Linux kernels before version 2.6.27.
+---
+ configure.in |   18 ++++++++++++++++++
+ pcap-linux.c |   18 ++++++++++--------
+ 2 files changed, 28 insertions(+), 8 deletions(-)
+
+diff --git configure.in configure.in
+index 24097b2..5eca6ab 100644
+--- configure.in
++++ configure.in
+@@ -1404,6 +1404,24 @@ linux*)
+ 	;;
+ esac
+ 
++dnl The packet ring capture facility of Linux, described in
++dnl Documentation/networking/packet_mmap.txt, is not 32/64-bit compatible before
++dnl version 2.6.27. A 32-bit kernel requires a 32-bit userland, and likewise for
++dnl 64-bit. The effect of this is that a 32-bit libpcap binary will not run
++dnl correctly on a 64-bit kernel (the binary will use the wrong offsets into a
++dnl kernel struct). This problem was solved in Linux 2.6.27. Use
++dnl --disable-packet-ring whenever a 32-bit application must run on a 64-bit
++dnl target host, and either the build host or the target host run Linux 2.6.26
++dnl or earlier.
++AC_ARG_ENABLE([packet-ring],
++[AC_HELP_STRING([--enable-packet-ring],[enable Linux packet ring support @<:@default=yes@:>@])],
++,enable_packet_ring=yes)
++
++if test "x$enable_packet_ring" != "xno" ; then
++	AC_DEFINE(PCAP_SUPPORT_PACKET_RING, 1, [use Linux packet ring capture if available])
++	AC_SUBST(PCAP_SUPPORT_PACKET_RING)
++fi
++
+ AC_PROG_INSTALL
+ 
+ AC_CONFIG_HEADER(config.h)
+diff --git pcap-linux.c pcap-linux.c
+index d4f50b7..213558b 100644
+--- pcap-linux.c
++++ pcap-linux.c
+@@ -219,14 +219,16 @@ static const char rcsid[] _U_ =
+  /* check for memory mapped access avaibility. We assume every needed 
+   * struct is defined if the macro TPACKET_HDRLEN is defined, because it
+   * uses many ring related structs and macros */
+-# ifdef TPACKET_HDRLEN
+-#  define HAVE_PACKET_RING
+-#  ifdef TPACKET2_HDRLEN
+-#   define HAVE_TPACKET2
+-#  else
+-#   define TPACKET_V1	0
+-#  endif /* TPACKET2_HDRLEN */
+-# endif /* TPACKET_HDRLEN */
++# ifdef PCAP_SUPPORT_PACKET_RING
++#  ifdef TPACKET_HDRLEN
++#   define HAVE_PACKET_RING
++#   ifdef TPACKET2_HDRLEN
++#    define HAVE_TPACKET2
++#   else
++#    define TPACKET_V1	0
++#   endif /* TPACKET2_HDRLEN */
++#  endif /* TPACKET_HDRLEN */
++# endif /* PCAP_SUPPORT_PACKET_RING */
+ #endif /* PF_PACKET */
+ 
+ #ifdef SO_ATTACH_FILTER
+-- 
+1.7.9.5
+
diff --git a/libpcap/NMAP_MODIFICATIONS/0004-Add-a-memset-call-that-removes-a-Valgrind-error.patch b/libpcap/NMAP_MODIFICATIONS/0004-Add-a-memset-call-that-removes-a-Valgrind-error.patch
new file mode 100644
index 000000000..227b7751b
--- /dev/null
+++ b/libpcap/NMAP_MODIFICATIONS/0004-Add-a-memset-call-that-removes-a-Valgrind-error.patch
@@ -0,0 +1,25 @@
+From 289ac878ff758d548628e7702618db3b0e141e0c Mon Sep 17 00:00:00 2001
+From: David Fifield <david@bamsoftware.com>
+Date: Mon, 9 Apr 2012 17:10:19 -0700
+Subject: [PATCH 4/4] Add a memset call that removes a Valgrind error.
+
+http://seclists.org/nmap-dev/2010/q3/796
+---
+ pcap-linux.c |    1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git pcap-linux.c pcap-linux.c
+index 213558b..97092ac 100644
+--- pcap-linux.c
++++ pcap-linux.c
+@@ -2315,6 +2315,7 @@ pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter,
+ 	struct sock_fprog	fcode;
+ 	int			can_filter_in_kernel;
+ 	int			err = 0;
++	memset(&fcode, 0, sizeof(struct sock_fprog));
+ #endif
+ 
+ 	if (!handle)
+-- 
+1.7.9.5
+
diff --git a/libpcap/NMAP_MODIFICATIONS/HOWTO-UPGRADE b/libpcap/NMAP_MODIFICATIONS/HOWTO-UPGRADE
new file mode 100644
index 000000000..0ecc29c81
--- /dev/null
+++ b/libpcap/NMAP_MODIFICATIONS/HOWTO-UPGRADE
@@ -0,0 +1,24 @@
+Download libpcap-X.Y.tar.gz from http://www.tcpdump.org/#latest-release
+and verify the signature.
+
+cd
+# Make a copy of this directory.
+cp -r ~/nmap/NMAP_MODIFICATIONS .
+tar xzvf libpcap-X.Y.tar.gz
+cd nmap
+rsync -rv --delete ~/libpcap-X.Y/ ~/nmap/libpcap/
+git add -A libpcap
+cd libpcap
+./configure
+make grammar.c scanner.c scanner.h tokdefs.h
+git add grammar.c scanner.c scanner.h tokdefs.h
+cd ..
+# Apply patches.
+git apply -p0 --directory=libpcap/ ~/NMAP_MODIFICATIONS/000*
+cd libpcap
+autoconf
+cd ..
+git add -u libpcap
+mv ~/NMAP_MODIFICATIONS libpcap/
+git add libpcap/NMAP_MODIFICATIONS
+git commit -m "Upgrade libpcap to X.Y."