path: root/package/libs/libpcap/patches/300-Add-support-for-B.A.T.M.A.N.-Advanced.patch

From 3d8d268320d2381021a409ff8d03533698dd6242 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20L=C3=BCssing?= <linus.luessing@c0d3.blue>
Date: Mon, 23 Nov 2020 00:38:22 +0100
Subject: [PATCH] Add support for B.A.T.M.A.N. Advanced
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This adds support for the layer 2 mesh routing protocol
B.A.T.M.A.N. Advanced. "batadv" can be used to filter on batman-adv
packets. It also allows later filters to look at frames inside the
tunnel when both "version" and "type" are specified.

Documentation for the batman-adv protocol can be found at the following
locations:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/batman-adv.rst
https://www.open-mesh.org/

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 Makefile.in            |   2 +
 batadv_legacy_packet.h |  77 +++++++++++++++++++
 batadv_packet.h        |  78 ++++++++++++++++++++
 ethertype.h            |   3 +
 gencode.c              | 164 +++++++++++++++++++++++++++++++++++++++++
 gencode.h              |   3 +
 grammar.y.in           |  32 +++++++-
 nametoaddr.c           |  59 +++++++++++++++
 pcap-filter.manmisc.in |  35 ++++++++-
 pcap/namedb.h          |   2 +
 scanner.l              |   1 +
 11 files changed, 453 insertions(+), 3 deletions(-)
 create mode 100644 batadv_legacy_packet.h
 create mode 100644 batadv_packet.h

--- a/Makefile.in
+++ b/Makefile.in
@@ -133,6 +133,8 @@ PUBHDR = \
 HDR = $(PUBHDR) \
 	arcnet.h \
 	atmuni31.h \
+	batadv_legacy_packet.h \
+	batadv_packet.h \
 	diag-control.h \
 	ethertype.h \
 	extract.h \
--- /dev/null
+++ b/batadv_legacy_packet.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: BSD-3 */
+/* Copyright (C) 2020  Linus Lüssing */
+
+#ifndef _BATADV_LEGACY_PACKET_H_
+#define _BATADV_LEGACY_PACKET_H_
+
+enum batadv_legacy_packettype {
+	BATADV_LEGACY_IV_OGM		= 0x01,
+	BATADV_LEGACY_ICMP		= 0x02,
+	BATADV_LEGACY_UNICAST		= 0x03,
+	BATADV_LEGACY_BCAST		= 0x04,
+	BATADV_LEGACY_VIS		= 0x05,
+	BATADV_LEGACY_UNICAST_FRAG	= 0x06,
+	BATADV_LEGACY_TT_QUERY		= 0x07,
+	BATADV_LEGACY_ROAM_ADV		= 0x08,
+	BATADV_LEGACY_UNICAST_4ADDR	= 0x09,
+	BATADV_LEGACY_CODED		= 0x0a,
+};
+
+#define ETH_ALEN	6
+
+struct batadv_legacy_unicast_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t ttvn;
+	uint8_t dest[ETH_ALEN];
+};
+
+struct batadv_legacy_unicast_4addr_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t src[ETH_ALEN];
+	uint8_t subtype;
+	uint8_t reserved;
+};
+
+struct batadv_legacy_unicast_frag_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t ttvn;
+	uint8_t dest[ETH_ALEN];
+	uint8_t flags;
+	uint8_t align;
+	uint8_t orig[ETH_ALEN];
+	uint8_t seqno[2];		/* 2-byte integral value */
+};
+
+struct batadv_legacy_bcast_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t reserved;
+	uint8_t seqno[4];		/* 4-byte integral value */
+	uint8_t orig[ETH_ALEN];
+};
+
+struct batadv_legacy_coded_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t first_ttvn;
+	uint8_t first_source[ETH_ALEN];
+	uint8_t first_orig_dest[ETH_ALEN];
+	uint8_t first_crc[4];		/* 4-byte integral value */
+	uint8_t second_ttl;
+	uint8_t second_ttvn;
+	uint8_t second_dest[ETH_ALEN];
+	uint8_t second_source[ETH_ALEN];
+	uint8_t second_orig_dest[ETH_ALEN];
+	uint8_t second_crc[4];		/* 4-byte integral value */
+	uint8_t coded_len[2];		/* 2-byte integral value */
+};
+
+#endif /* _BATADV_LEGACY_PACKET_H_ */
--- /dev/null
+++ b/batadv_packet.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: BSD-3 */
+/* Copyright (C) 2020  Linus Lüssing */
+
+#ifndef _BATADV_PACKET_H_
+#define _BATADV_PACKET_H_
+
+/* For the definitive and most recent packet format definition,
+ * see the batadv_packet.h in the Linux kernel.
+ */
+
+enum batadv_packettype {
+	BATADV_IV_OGM           = 0x00,
+	BATADV_BCAST            = 0x01,
+	BATADV_CODED            = 0x02,
+	BATADV_ELP		= 0x03,
+	BATADV_OGM2		= 0x04,
+	BATADV_UNICAST          = 0x40,
+	BATADV_UNICAST_FRAG     = 0x41,
+	BATADV_UNICAST_4ADDR    = 0x42,
+	BATADV_ICMP             = 0x43,
+	BATADV_UNICAST_TVLV     = 0x44,
+};
+
+#define ETH_ALEN	6
+
+struct batadv_unicast_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t ttvn;
+	uint8_t dest[ETH_ALEN];
+};
+
+struct batadv_unicast_4addr_packet {
+	struct batadv_unicast_packet u;
+	uint8_t src[ETH_ALEN];
+	uint8_t subtype;
+	uint8_t reserved;
+};
+
+struct batadv_frag_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t num_pri;	/* number and priority */
+	uint8_t dest[ETH_ALEN];
+	uint8_t orig[ETH_ALEN];
+	uint8_t seqno[2];	/* 2-byte integral value */
+	uint8_t total_size[2];	/* 2-byte integral value */
+};
+
+struct batadv_bcast_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t reserved;
+	uint8_t seqno[4];	/* 4-byte integral value */
+	uint8_t orig[ETH_ALEN];
+};
+
+struct batadv_coded_packet {
+	uint8_t packet_type;
+	uint8_t version;
+	uint8_t ttl;
+	uint8_t first_ttvn;
+	uint8_t first_source[ETH_ALEN];
+	uint8_t first_orig_dest[ETH_ALEN];
+	uint8_t first_crc[4];	/* 4-byte integral value */
+	uint8_t second_ttl;
+	uint8_t second_ttvn;
+	uint8_t second_dest[ETH_ALEN];
+	uint8_t second_source[ETH_ALEN];
+	uint8_t second_orig_dest[ETH_ALEN];
+	uint8_t second_crc[4];	/* 4-byte integral value */
+	uint8_t coded_len[2];	/* 2-byte integral value */
+};
+
+#endif /* _BATADV_PACKET_H_ */
--- a/ethertype.h
+++ b/ethertype.h
@@ -49,6 +49,9 @@
 #ifndef ETHERTYPE_TRAIL
 #define ETHERTYPE_TRAIL		0x1000
 #endif
+#ifndef ETHERTYPE_BATMAN
+#define ETHERTYPE_BATMAN	0x4305 /* B.A.T.M.A.N. Advanced */
+#endif
 #ifndef	ETHERTYPE_MOPDL
 #define ETHERTYPE_MOPDL		0x6001
 #endif
--- a/gencode.c
+++ b/gencode.c
@@ -60,6 +60,8 @@
 #include "sunatmpos.h"
 #include "pflog.h"
 #include "ppp.h"
+#include "batadv_packet.h"
+#include "batadv_legacy_packet.h"
 #include "pcap/sll.h"
 #include "pcap/ipnet.h"
 #include "arcnet.h"
@@ -9436,6 +9438,168 @@ gen_geneve(compiler_state_t *cstate, bpf
 	return b1;
 }
 
+static struct block *
+gen_batadv_check_version(compiler_state_t *cstate, struct block *b0, bpf_u_int32 version)
+{
+	struct block *b1;
+
+	if (version > UINT8_MAX)
+		bpf_error(cstate,
+			  "batman-adv compatibility version number %u unsupported",
+			  version);
+
+	b1 = gen_cmp(cstate, OR_LINKPL, 1, BPF_B, version);
+	gen_and(b0, b1);
+
+	return b1;
+}
+
+static struct block *
+gen_batadv_check_type(compiler_state_t *cstate, struct block *b0,
+		      bpf_u_int32 version, bpf_u_int32 type)
+{
+	struct block *b1;
+
+	switch (version) {
+	case 14:
+	case 15:
+		if (type > UINT8_MAX)
+			bpf_error(cstate,
+				  "batman-adv packet type %u unsupported for compatibility version %u",
+				  type, version);
+
+		b1 = gen_cmp(cstate, OR_LINKPL, 0, BPF_B, type);
+		gen_and(b0, b1);
+		b0 = b1;
+
+		break;
+	default:
+		bpf_error(cstate,
+			  "batman-adv compatibility version number %u unsupported",
+			  version);
+	}
+
+	return b0;
+}
+
+
+static void gen_batadv_push_offset(compiler_state_t *cstate, u_int offset)
+{
+	PUSH_LINKHDR(cstate, DLT_EN10MB, cstate->off_linkpl.is_variable,
+		     cstate->off_linkpl.constant_part + cstate->off_nl + offset,
+		     cstate->off_linkpl.reg);
+
+	cstate->off_linktype.constant_part += cstate->off_linkhdr.constant_part;
+	cstate->off_linkpl.constant_part += cstate->off_linkhdr.constant_part;
+
+	cstate->off_nl = 0;
+	cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
+}
+
+static void
+gen_batadv_offsets_v14(compiler_state_t *cstate, bpf_u_int32 type)
+{
+	size_t offset;
+
+	switch (type) {
+	case BATADV_LEGACY_UNICAST:		/* 0x03 */
+		offset = sizeof(struct batadv_legacy_unicast_packet);
+		break;
+	case BATADV_LEGACY_BCAST:		/* 0x04 */
+		offset = sizeof(struct batadv_legacy_bcast_packet);
+		break;
+	case BATADV_LEGACY_UNICAST_FRAG:	/* 0x06 */
+		offset = sizeof(struct batadv_legacy_unicast_frag_packet);
+		break;
+	case BATADV_LEGACY_UNICAST_4ADDR:	/* 0x09 */
+		offset = sizeof(struct batadv_legacy_unicast_4addr_packet);
+		break;
+	case BATADV_LEGACY_CODED:		/* 0x0a */
+		offset = sizeof(struct batadv_legacy_coded_packet);
+		break;
+	default:
+		offset = 0;
+	}
+
+	if (offset)
+		gen_batadv_push_offset(cstate, (u_int)offset);
+}
+
+static void
+gen_batadv_offsets_v15(compiler_state_t *cstate, bpf_u_int32 type)
+{
+	size_t offset;
+
+	switch (type) {
+	case BATADV_BCAST:		/* 0x01 */
+		offset = sizeof(struct batadv_bcast_packet);
+		break;
+	case BATADV_CODED:		/* 0x02 */
+		offset = sizeof(struct batadv_coded_packet);
+		break;
+	case BATADV_UNICAST:		/* 0x40 */
+		offset = sizeof(struct batadv_unicast_packet);
+		break;
+	case BATADV_UNICAST_FRAG:	/* 0x41 */
+		offset = sizeof(struct batadv_frag_packet);
+		break;
+	case BATADV_UNICAST_4ADDR:	/* 0x42 */
+		offset = sizeof(struct batadv_unicast_4addr_packet);
+		break;
+	case BATADV_UNICAST_TVLV:
+		/* unsupported for now, needs variable offset to
+		 * take tvlv_len into account
+		 */
+		/* fall through */
+	default:
+		offset = 0;
+	}
+
+	if (offset)
+		gen_batadv_push_offset(cstate, (u_int)offset);
+}
+
+static void
+gen_batadv_offsets(compiler_state_t *cstate, bpf_u_int32 version, bpf_u_int32 type)
+{
+	switch (version) {
+	case 14:
+		gen_batadv_offsets_v14(cstate, type);
+		break;
+	case 15:
+		gen_batadv_offsets_v15(cstate, type);
+		break;
+	default:
+		break;
+	}
+}
+
+struct block *
+gen_batadv(compiler_state_t *cstate, bpf_u_int32 version, int has_version,
+	   bpf_u_int32 type, int has_type)
+{
+	struct block *b0;
+
+	/*
+	 * Catch errors reported by us and routines below us, and return NULL
+	 * on an error.
+	 */
+	if (setjmp(cstate->top_ctx))
+		return (NULL);
+
+	b0 = gen_linktype(cstate, ETHERTYPE_BATMAN);
+
+	if (has_version)
+		b0 = gen_batadv_check_version(cstate, b0, version);
+
+	if (has_type) {
+		b0 = gen_batadv_check_type(cstate, b0, version, type);
+		gen_batadv_offsets(cstate, version, type);
+	}
+
+	return b0;
+}
+
 /* Check that the encapsulated frame has a link layer header
  * for Ethernet filters. */
 static struct block *
--- a/gencode.h
+++ b/gencode.h
@@ -358,6 +358,9 @@ struct block *gen_pppoes(compiler_state_
 
 struct block *gen_geneve(compiler_state_t *, bpf_u_int32, int);
 
+struct block *gen_batadv(compiler_state_t *, bpf_u_int32, int,
+			 bpf_u_int32, int);
+
 struct block *gen_atmfield_code(compiler_state_t *, int, bpf_u_int32,
     int, int);
 struct block *gen_atmtype_abbrev(compiler_state_t *, int);
--- a/grammar.y.in
+++ b/grammar.y.in
@@ -375,6 +375,7 @@ DIAG_OFF_BISON_BYACC
 %type	<i>	mtp2type
 %type	<blk>	mtp3field
 %type	<blk>	mtp3fieldvalue mtp3value mtp3listvalue
+%type	<rblk>	pbatadv
 
 
 %token  DST SRC HOST GATEWAY
@@ -393,7 +394,7 @@ DIAG_OFF_BISON_BYACC
 %token  LEN
 %token  IPV6 ICMPV6 AH ESP
 %token	VLAN MPLS
-%token	PPPOED PPPOES GENEVE
+%token	PPPOED PPPOES GENEVE BATADV
 %token  ISO ESIS CLNP ISIS L1 L2 IIH LSP SNP CSNP PSNP
 %token  STP
 %token  IPX
@@ -620,11 +621,40 @@ other:	  pqual TK_BROADCAST	{ CHECK_PTR_
 	| PPPOES		{ CHECK_PTR_VAL(($$ = gen_pppoes(cstate, 0, 0))); }
 	| GENEVE pnum		{ CHECK_PTR_VAL(($$ = gen_geneve(cstate, $2, 1))); }
 	| GENEVE		{ CHECK_PTR_VAL(($$ = gen_geneve(cstate, 0, 0))); }
+	| BATADV pbatadv	{ $$ = $2; }
 	| pfvar			{ $$ = $1; }
 	| pqual p80211		{ $$ = $2; }
 	| pllc			{ $$ = $1; }
 	;
 
+pbatadv:		{ CHECK_PTR_VAL(($$ = gen_batadv(cstate, 0, 0, 0, 0))); }
+	| pnum		{ CHECK_PTR_VAL(($$ = gen_batadv(cstate, $1, 1, 0, 0))); }
+	| pnum pnum	{ CHECK_PTR_VAL(($$ = gen_batadv(cstate, $1, 1, $2, 1))); }
+	| pnum ID
+		{
+			int type;
+
+			switch ($1) {
+			case 14:
+				type = pcap_nametobatadvtype_v14($2);
+				break;
+			case 15:
+				type = pcap_nametobatadvtype_v15($2);
+				break;
+			default:
+				bpf_set_error(cstate, "batman-adv compatibility version number %u unsupported", $1);
+				YYABORT;
+			}
+
+			if (type == PROTO_UNDEF) {
+				bpf_set_error(cstate, "invalid batman-adv packet type value \"%s\"", $2);
+				YYABORT;
+			}
+
+			CHECK_PTR_VAL(($$ = gen_batadv(cstate, $1, 1, type, 1)));
+		}
+	;
+
 pfvar:	  PF_IFNAME ID		{ CHECK_PTR_VAL($2); CHECK_PTR_VAL(($$ = gen_pf_ifname(cstate, $2))); }
 	| PF_RSET ID		{ CHECK_PTR_VAL($2); CHECK_PTR_VAL(($$ = gen_pf_ruleset(cstate, $2))); }
 	| PF_RNR NUM		{ CHECK_PTR_VAL(($$ = gen_pf_rnr(cstate, $2))); }
--- a/nametoaddr.c
+++ b/nametoaddr.c
@@ -136,8 +136,12 @@
 
 #include "diag-control.h"
 
+#include "batadv_packet.h"
+#include "batadv_legacy_packet.h"
+
 #include "gencode.h"
 #include <pcap/namedb.h>
+
 #include "nametoaddr.h"
 
 #ifdef HAVE_OS_PROTO_H
@@ -604,6 +608,7 @@ PCAP_API_DEF struct eproto eproto_db[] =
 	{ "moprc", ETHERTYPE_MOPRC },
 	{ "rarp", ETHERTYPE_REVARP },
 	{ "sca", ETHERTYPE_SCA },
+	{ "batadv", ETHERTYPE_BATMAN },
 	{ (char *)0, 0 }
 };
 
@@ -638,6 +643,60 @@ pcap_nametollc(const char *s)
 
 	while (p->s != 0) {
 		if (strcmp(p->s, s) == 0)
+			return p->p;
+		p += 1;
+	}
+	return PROTO_UNDEF;
+}
+
+/* Static data base of batman-adv v14 packet type values. */
+static struct eproto batadv_type_db_v14[] = {
+	{ "iv_ogm",		BATADV_LEGACY_IV_OGM },
+	{ "icmp",		BATADV_LEGACY_ICMP },
+	{ "unicast",		BATADV_LEGACY_UNICAST },
+	{ "bcast",		BATADV_LEGACY_BCAST },
+	{ "vis",		BATADV_LEGACY_VIS },
+	{ "unicast_frag",	BATADV_LEGACY_UNICAST_FRAG },
+	{ "tt_query",		BATADV_LEGACY_TT_QUERY },
+	{ "roam_adv",		BATADV_LEGACY_ROAM_ADV },
+	{ "unicast_4addr",	BATADV_LEGACY_UNICAST_4ADDR },
+	{ "coded",		BATADV_LEGACY_CODED },
+	{ (char *)0, 0 }
+};
+
+int pcap_nametobatadvtype_v14(const char *s)
+{
+	struct eproto *p = batadv_type_db_v14;
+
+	while (p->s != 0) {
+		if (strcmp(p->s, s) == 0)
+			return p->p;
+		p += 1;
+	}
+	return PROTO_UNDEF;
+}
+
+/* Static data base of batman-adv v15 packet type values. */
+static struct eproto batadv_type_db_v15[] = {
+	{ "iv_ogm",		BATADV_IV_OGM },
+	{ "bcast",		BATADV_BCAST },
+	{ "coded",		BATADV_CODED },
+	{ "elp",		BATADV_ELP },
+	{ "ogm2",		BATADV_OGM2 },
+	{ "unicast",		BATADV_UNICAST },
+	{ "unicast_frag",	BATADV_UNICAST_FRAG },
+	{ "unicast_4addr",	BATADV_UNICAST_4ADDR },
+	{ "icmp",		BATADV_ICMP },
+	{ "unicast_tvlv",	BATADV_UNICAST_TVLV },
+	{ (char *)0, 0 }
+};
+
+int pcap_nametobatadvtype_v15(const char *s)
+{
+	struct eproto *p = batadv_type_db_v15;
+
+	while (p->s != 0) {
+		if (strcmp(p->s, s) == 0)
 			return p->p;
 		p += 1;
 	}
--- a/pcap-filter.manmisc.in
+++ b/pcap-filter.manmisc.in
@@ -98,6 +98,7 @@ protocols are:
 .BR arp ,
 .BR rarp ,
 .BR decnet ,
+.BR batadv ,
 .BR sctp ,
 .B tcp
 and
@@ -400,7 +401,7 @@ True if the packet is an IPv6 multicast
 .IP  "\fBether proto \fIprotocol\fR"
 True if the packet is of ether type \fIprotocol\fR.
 \fIProtocol\fP can be a number or one of the names
-\fBaarp\fP, \fBarp\fP, \fBatalk\fP, \fBdecnet\fP, \fBip\fP, \fBip6\fP,
+\fBaarp\fP, \fBarp\fP, \fBatalk\fP, \fBbatadv\fP, \fBdecnet\fP, \fBip\fP, \fBip6\fP,
 \fBipx\fP, \fBiso\fP, \fBlat\fP, \fBloopback\fP, \fBmopdl\fP, \fBmoprc\fP, \fBnetbeui\fP,
 \fBrarp\fP, \fBsca\fP or \fBstp\fP.
 Note these identifiers (except \fBloopback\fP) are also keywords
@@ -454,7 +455,7 @@ the filter checks for the IPX etype in a
 DSAP in the LLC header, the 802.3-with-no-LLC-header encapsulation of
 IPX, and the IPX etype in a SNAP frame.
 .RE
-.IP "\fBip\fR, \fBip6\fR, \fBarp\fR, \fBrarp\fR, \fBatalk\fR, \fBaarp\fR, \fBdecnet\fR, \fBiso\fR, \fBstp\fR, \fBipx\fR, \fBnetbeui\fP"
+.IP "\fBip\fR, \fBip6\fR, \fBarp\fR, \fBrarp\fR, \fBatalk\fR, \fBaarp\fR, \fBdecnet\fR, \fBiso\fR, \fBstp\fR, \fBipx\fR, \fBnetbeui\fP, \fBbatadv\fP"
 Abbreviations for:
 .in +.5i
 .nf
@@ -792,6 +793,36 @@ For example:
 filters IPv4 protocol encapsulated in Geneve with VNI 0xb. This will
 match both IPv4 directly encapsulated in Geneve as well as IPv4 contained
 inside an Ethernet frame.
+.IP "\fBbatadv \fI[version] \fI[type]\fR"
+True if the packet is a B.A.T.M.A.N. Advanced packet (Ethernet type 0x4305).
+If the optional \fIversion\fR is specified, only true if the packet has the
+specified batman-adv compatibility \fIversion\fR. If the optional \fIversion\fR
+and \fItype\fR are specified, only true if the packet has both the specified
+batman-adv compatibility \fIversion\fR and batman-adv packet \fItype\fR.
+.IP
+\fIversion\fR may be a number from 0 to 255, though only compatibility version
+14 and 15 were actually deployed in the wild. Version 15 is the current version,
+14 is considered deprecated.
+.IP
+\fItype\fR is currently only defined for compatibility \fIversion\fR 14 and 15.
+\fItype\fR may be a number from 0 to 255 for compatibility \fIversion\fR 14 and 15.
+.IP
+The following packet \fItype\fR aliases are available for compat \fIversion\fR 14:
+\fBiv_ogm\fP, \fBicmp\fP, \fBunicast\fP, \fBbcast\fP, \fBvis\fP, \fBunicast-frag\fP,
+\fBtt_query\fP, \fBroam_adv\fP, \fBunicast_4addr\fP, \fPcoded\fP.
+.IP
+The following packet \fItype\fR aliases are available for compat \fIversion\fR 15:
+\fBiv_ogm\fP, \fBbcast\fP, \fBcoded\fP, \fBelp\fP, \fBogm2\fP, \fBunicast\fP,
+\fBunicast_frag\fP, \fBunicast_4addr\fP, \fBicmp\fP, \fPunicast_tvlv\fP.
+.IP
+Note that when the \fBbatadv\fR keyword is encountered in an expression and
+a batman-adv packet \fItype\fR is provided which specifies an encapsulating
+packet type then it changes the decoding offsets for the remainder of the
+expression on the assumption that the packet is a batman-adv packet. For compat
+\fIversion\fR 14 these are packet \fItype\fRs \fBunicast\fP, \fBbcast\fP,
+\fBunicast_frag\fP, \fBunicast_4addr\fP and \fBcoded\fP. For compat \fIversion\fR
+15 these are currently packet \fItype\fRs \fBbcast\fP, \fBcoded\fP, \fBunicast\fP,
+\fBunicast_frag\fP and \fBunicast_4addr\fP.
 .IP "\fBiso proto \fIprotocol\fR"
 True if the packet is an OSI packet of protocol type \fIprotocol\fP.
 \fIProtocol\fP can be a number or one of the names
--- a/pcap/namedb.h
+++ b/pcap/namedb.h
@@ -70,6 +70,8 @@ PCAP_API int	pcap_nametoportrange(const
 PCAP_API int	pcap_nametoproto(const char *);
 PCAP_API int	pcap_nametoeproto(const char *);
 PCAP_API int	pcap_nametollc(const char *);
+PCAP_API int	pcap_nametobatadvtype_v14(const char *);
+PCAP_API int	pcap_nametobatadvtype_v15(const char *);
 /*
  * If a protocol is unknown, PROTO_UNDEF is returned.
  * Also, pcap_nametoport() returns the protocol along with the port number.
--- a/scanner.l
+++ b/scanner.l
@@ -347,6 +347,7 @@ mpls		return MPLS;
 pppoed		return PPPOED;
 pppoes		return PPPOES;
 geneve		return GENEVE;
+batadv		return BATADV;
 
 lane		return LANE;
 llc		return LLC;