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Add support for B.A.T.M.A.N. Advanced
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>
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11 files changed

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‎Makefile.in

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@@ -125,6 +125,8 @@ PUBHDR = \
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HDR = $(PUBHDR) \
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arcnet.h \
127127
atmuni31.h \
128+
batadv_legacy_packet.h \
129+
batadv_packet.h \
128130
diag-control.h \
129131
ethertype.h \
130132
extract.h \

‎batadv_legacy_packet.h

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@@ -0,0 +1,77 @@
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/* SPDX-License-Identifier: BSD-3 */
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/* Copyright (C) 2020 Linus Lüssing */
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#ifndef _BATADV_LEGACY_PACKET_H_
5+
#define _BATADV_LEGACY_PACKET_H_
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7+
enum batadv_legacy_packettype {
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BATADV_LEGACY_IV_OGM = 0x01,
9+
BATADV_LEGACY_ICMP = 0x02,
10+
BATADV_LEGACY_UNICAST = 0x03,
11+
BATADV_LEGACY_BCAST = 0x04,
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BATADV_LEGACY_VIS = 0x05,
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BATADV_LEGACY_UNICAST_FRAG = 0x06,
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BATADV_LEGACY_TT_QUERY = 0x07,
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BATADV_LEGACY_ROAM_ADV = 0x08,
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BATADV_LEGACY_UNICAST_4ADDR = 0x09,
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BATADV_LEGACY_CODED = 0x0a,
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};
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#define ETH_ALEN 6
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struct batadv_legacy_unicast_packet {
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uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
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uint8_t ttvn;
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uint8_t dest[ETH_ALEN];
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};
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struct batadv_legacy_unicast_4addr_packet {
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uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
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uint8_t src[ETH_ALEN];
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uint8_t subtype;
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uint8_t reserved;
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};
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struct batadv_legacy_unicast_frag_packet {
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uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
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uint8_t ttvn;
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uint8_t dest[ETH_ALEN];
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uint8_t flags;
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uint8_t align;
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uint8_t orig[ETH_ALEN];
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uint8_t seqno[2]; /* 2-byte integral value */
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};
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struct batadv_legacy_bcast_packet {
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uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
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uint8_t reserved;
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uint8_t seqno[4]; /* 4-byte integral value */
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uint8_t orig[ETH_ALEN];
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};
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struct batadv_legacy_coded_packet {
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uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
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uint8_t first_ttvn;
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uint8_t first_source[ETH_ALEN];
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uint8_t first_orig_dest[ETH_ALEN];
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uint8_t first_crc[4]; /* 4-byte integral value */
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uint8_t second_ttl;
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uint8_t second_ttvn;
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uint8_t second_dest[ETH_ALEN];
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uint8_t second_source[ETH_ALEN];
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uint8_t second_orig_dest[ETH_ALEN];
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uint8_t second_crc[4]; /* 4-byte integral value */
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uint8_t coded_len[2]; /* 2-byte integral value */
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};
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#endif /* _BATADV_LEGACY_PACKET_H_ */

‎batadv_packet.h

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@@ -0,0 +1,78 @@
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/* SPDX-License-Identifier: BSD-3 */
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/* Copyright (C) 2020 Linus Lüssing */
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#ifndef _BATADV_PACKET_H_
5+
#define _BATADV_PACKET_H_
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/* For the definitive and most recent packet format definition,
8+
* see the batadv_packet.h in the Linux kernel.
9+
*/
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11+
enum batadv_packettype {
12+
BATADV_IV_OGM = 0x00,
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BATADV_BCAST = 0x01,
14+
BATADV_CODED = 0x02,
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BATADV_ELP = 0x03,
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BATADV_OGM2 = 0x04,
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BATADV_UNICAST = 0x40,
18+
BATADV_UNICAST_FRAG = 0x41,
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BATADV_UNICAST_4ADDR = 0x42,
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BATADV_ICMP = 0x43,
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BATADV_UNICAST_TVLV = 0x44,
22+
};
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#define ETH_ALEN 6
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struct batadv_unicast_packet {
27+
uint8_t packet_type;
28+
uint8_t version;
29+
uint8_t ttl;
30+
uint8_t ttvn;
31+
uint8_t dest[ETH_ALEN];
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};
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struct batadv_unicast_4addr_packet {
35+
struct batadv_unicast_packet u;
36+
uint8_t src[ETH_ALEN];
37+
uint8_t subtype;
38+
uint8_t reserved;
39+
};
40+
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struct batadv_frag_packet {
42+
uint8_t packet_type;
43+
uint8_t version;
44+
uint8_t ttl;
45+
uint8_t num_pri; /* number and priority */
46+
uint8_t dest[ETH_ALEN];
47+
uint8_t orig[ETH_ALEN];
48+
uint8_t seqno[2]; /* 2-byte integral value */
49+
uint8_t total_size[2]; /* 2-byte integral value */
50+
};
51+
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struct batadv_bcast_packet {
53+
uint8_t packet_type;
54+
uint8_t version;
55+
uint8_t ttl;
56+
uint8_t reserved;
57+
uint8_t seqno[4]; /* 4-byte integral value */
58+
uint8_t orig[ETH_ALEN];
59+
};
60+
61+
struct batadv_coded_packet {
62+
uint8_t packet_type;
63+
uint8_t version;
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uint8_t ttl;
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uint8_t first_ttvn;
66+
uint8_t first_source[ETH_ALEN];
67+
uint8_t first_orig_dest[ETH_ALEN];
68+
uint8_t first_crc[4]; /* 4-byte integral value */
69+
uint8_t second_ttl;
70+
uint8_t second_ttvn;
71+
uint8_t second_dest[ETH_ALEN];
72+
uint8_t second_source[ETH_ALEN];
73+
uint8_t second_orig_dest[ETH_ALEN];
74+
uint8_t second_crc[4]; /* 4-byte integral value */
75+
uint8_t coded_len[2]; /* 2-byte integral value */
76+
};
77+
78+
#endif /* _BATADV_PACKET_H_ */

‎ethertype.h

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@@ -49,6 +49,9 @@
4949
#ifndef ETHERTYPE_TRAIL
5050
#define ETHERTYPE_TRAIL 0x1000
5151
#endif
52+
#ifndef ETHERTYPE_BATMAN
53+
#define ETHERTYPE_BATMAN 0x4305 /* B.A.T.M.A.N. Advanced */
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#endif
5255
#ifndef ETHERTYPE_MOPDL
5356
#define ETHERTYPE_MOPDL 0x6001
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#endif

‎gencode.c

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@@ -56,6 +56,8 @@
5656
#include "sunatmpos.h"
5757
#include "pflog.h"
5858
#include "ppp.h"
59+
#include "batadv_packet.h"
60+
#include "batadv_legacy_packet.h"
5961
#include "pcap/sll.h"
6062
#include "pcap/ipnet.h"
6163
#include "arcnet.h"
@@ -9731,6 +9733,168 @@ gen_geneve(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
97319733
return b1;
97329734
}
97339735

9736+
static struct block *
9737+
gen_batadv_check_version(compiler_state_t *cstate, struct block *b0, bpf_u_int32 version)
9738+
{
9739+
struct block *b1;
9740+
9741+
if (version > UINT8_MAX)
9742+
bpf_error(cstate,
9743+
"batman-adv compatibility version number %u unsupported",
9744+
version);
9745+
9746+
b1 = gen_cmp(cstate, OR_LINKPL, 1, BPF_B, version);
9747+
gen_and(b0, b1);
9748+
9749+
return b1;
9750+
}
9751+
9752+
static struct block *
9753+
gen_batadv_check_type(compiler_state_t *cstate, struct block *b0,
9754+
bpf_u_int32 version, bpf_u_int32 type)
9755+
{
9756+
struct block *b1;
9757+
9758+
switch (version) {
9759+
case 14:
9760+
case 15:
9761+
if (type > UINT8_MAX)
9762+
bpf_error(cstate,
9763+
"batman-adv packet type %u unsupported for compatibility version %u",
9764+
type, version);
9765+
9766+
b1 = gen_cmp(cstate, OR_LINKPL, 0, BPF_B, type);
9767+
gen_and(b0, b1);
9768+
b0 = b1;
9769+
9770+
break;
9771+
default:
9772+
bpf_error(cstate,
9773+
"batman-adv compatibility version number %u unsupported",
9774+
version);
9775+
}
9776+
9777+
return b0;
9778+
}
9779+
9780+
9781+
static void gen_batadv_push_offset(compiler_state_t *cstate, u_int offset)
9782+
{
9783+
PUSH_LINKHDR(cstate, DLT_EN10MB, cstate->off_linkpl.is_variable,
9784+
cstate->off_linkpl.constant_part + cstate->off_nl + offset,
9785+
cstate->off_linkpl.reg);
9786+
9787+
cstate->off_linktype.constant_part += cstate->off_linkhdr.constant_part;
9788+
cstate->off_linkpl.constant_part += cstate->off_linkhdr.constant_part;
9789+
9790+
cstate->off_nl = 0;
9791+
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
9792+
}
9793+
9794+
static void
9795+
gen_batadv_offsets_v14(compiler_state_t *cstate, bpf_u_int32 type)
9796+
{
9797+
size_t offset;
9798+
9799+
switch (type) {
9800+
case BATADV_LEGACY_UNICAST: /* 0x03 */
9801+
offset = sizeof(struct batadv_legacy_unicast_packet);
9802+
break;
9803+
case BATADV_LEGACY_BCAST: /* 0x04 */
9804+
offset = sizeof(struct batadv_legacy_bcast_packet);
9805+
break;
9806+
case BATADV_LEGACY_UNICAST_FRAG: /* 0x06 */
9807+
offset = sizeof(struct batadv_legacy_unicast_frag_packet);
9808+
break;
9809+
case BATADV_LEGACY_UNICAST_4ADDR: /* 0x09 */
9810+
offset = sizeof(struct batadv_legacy_unicast_4addr_packet);
9811+
break;
9812+
case BATADV_LEGACY_CODED: /* 0x0a */
9813+
offset = sizeof(struct batadv_legacy_coded_packet);
9814+
break;
9815+
default:
9816+
offset = 0;
9817+
}
9818+
9819+
if (offset)
9820+
gen_batadv_push_offset(cstate, (u_int)offset);
9821+
}
9822+
9823+
static void
9824+
gen_batadv_offsets_v15(compiler_state_t *cstate, bpf_u_int32 type)
9825+
{
9826+
size_t offset;
9827+
9828+
switch (type) {
9829+
case BATADV_BCAST: /* 0x01 */
9830+
offset = sizeof(struct batadv_bcast_packet);
9831+
break;
9832+
case BATADV_CODED: /* 0x02 */
9833+
offset = sizeof(struct batadv_coded_packet);
9834+
break;
9835+
case BATADV_UNICAST: /* 0x40 */
9836+
offset = sizeof(struct batadv_unicast_packet);
9837+
break;
9838+
case BATADV_UNICAST_FRAG: /* 0x41 */
9839+
offset = sizeof(struct batadv_frag_packet);
9840+
break;
9841+
case BATADV_UNICAST_4ADDR: /* 0x42 */
9842+
offset = sizeof(struct batadv_unicast_4addr_packet);
9843+
break;
9844+
case BATADV_UNICAST_TVLV:
9845+
/* unsupported for now, needs variable offset to
9846+
* take tvlv_len into account
9847+
*/
9848+
/* fall through */
9849+
default:
9850+
offset = 0;
9851+
}
9852+
9853+
if (offset)
9854+
gen_batadv_push_offset(cstate, (u_int)offset);
9855+
}
9856+
9857+
static void
9858+
gen_batadv_offsets(compiler_state_t *cstate, bpf_u_int32 version, bpf_u_int32 type)
9859+
{
9860+
switch (version) {
9861+
case 14:
9862+
gen_batadv_offsets_v14(cstate, type);
9863+
break;
9864+
case 15:
9865+
gen_batadv_offsets_v15(cstate, type);
9866+
break;
9867+
default:
9868+
break;
9869+
}
9870+
}
9871+
9872+
struct block *
9873+
gen_batadv(compiler_state_t *cstate, bpf_u_int32 version, int has_version,
9874+
bpf_u_int32 type, int has_type)
9875+
{
9876+
struct block *b0;
9877+
9878+
/*
9879+
* Catch errors reported by us and routines below us, and return NULL
9880+
* on an error.
9881+
*/
9882+
if (setjmp(cstate->top_ctx))
9883+
return (NULL);
9884+
9885+
b0 = gen_linktype(cstate, ETHERTYPE_BATMAN);
9886+
9887+
if (has_version)
9888+
b0 = gen_batadv_check_version(cstate, b0, version);
9889+
9890+
if (has_type) {
9891+
b0 = gen_batadv_check_type(cstate, b0, version, type);
9892+
gen_batadv_offsets(cstate, version, type);
9893+
}
9894+
9895+
return b0;
9896+
}
9897+
97349898
/* Check that the encapsulated frame has a link layer header
97359899
* for Ethernet filters. */
97369900
static struct block *

‎gencode.h

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@@ -358,6 +358,9 @@ struct block *gen_pppoes(compiler_state_t *, bpf_u_int32, int);
358358

359359
struct block *gen_geneve(compiler_state_t *, bpf_u_int32, int);
360360

361+
struct block *gen_batadv(compiler_state_t *, bpf_u_int32, int,
362+
bpf_u_int32, int);
363+
361364
struct block *gen_atmfield_code(compiler_state_t *, int, bpf_u_int32,
362365
int, int);
363366
struct block *gen_atmtype_abbrev(compiler_state_t *, int);

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