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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>
1 parent bcd6c3f commit cf95dad

10 files changed

+453
-3
lines changed

‎batadv_legacy_packet.h

+77
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@@ -0,0 +1,77 @@
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/* SPDX-License-Identifier: BSD-3 */
2+
/* Copyright (C) 2020 Linus Lüssing */
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#ifndef _BATADV_LEGACY_PACKET_H_
5+
#define _BATADV_LEGACY_PACKET_H_
6+
7+
enum batadv_legacy_packettype {
8+
BATADV_LEGACY_IV_OGM = 0x01,
9+
BATADV_LEGACY_ICMP = 0x02,
10+
BATADV_LEGACY_UNICAST = 0x03,
11+
BATADV_LEGACY_BCAST = 0x04,
12+
BATADV_LEGACY_VIS = 0x05,
13+
BATADV_LEGACY_UNICAST_FRAG = 0x06,
14+
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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20+
#define ETH_ALEN 6
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22+
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 {
31+
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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};
38+
39+
struct batadv_legacy_unicast_frag_packet {
40+
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];
48+
uint8_t seqno[2]; /* 2-byte integral value */
49+
};
50+
51+
struct batadv_legacy_bcast_packet {
52+
uint8_t packet_type;
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uint8_t version;
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uint8_t ttl;
55+
uint8_t reserved;
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uint8_t seqno[4]; /* 4-byte integral value */
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uint8_t orig[ETH_ALEN];
58+
};
59+
60+
struct batadv_legacy_coded_packet {
61+
uint8_t packet_type;
62+
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];
71+
uint8_t second_source[ETH_ALEN];
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uint8_t second_orig_dest[ETH_ALEN];
73+
uint8_t second_crc[4]; /* 4-byte integral value */
74+
uint8_t coded_len[2]; /* 2-byte integral value */
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};
76+
77+
#endif /* _BATADV_LEGACY_PACKET_H_ */

‎batadv_packet.h

+78
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@@ -0,0 +1,78 @@
1+
/* SPDX-License-Identifier: BSD-3 */
2+
/* 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,
13+
BATADV_BCAST = 0x01,
14+
BATADV_CODED = 0x02,
15+
BATADV_ELP = 0x03,
16+
BATADV_OGM2 = 0x04,
17+
BATADV_UNICAST = 0x40,
18+
BATADV_UNICAST_FRAG = 0x41,
19+
BATADV_UNICAST_4ADDR = 0x42,
20+
BATADV_ICMP = 0x43,
21+
BATADV_UNICAST_TVLV = 0x44,
22+
};
23+
24+
#define ETH_ALEN 6
25+
26+
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];
32+
};
33+
34+
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+
41+
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+
52+
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;
64+
uint8_t ttl;
65+
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

+3
Original file line numberDiff line numberDiff line change
@@ -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 */
54+
#endif
5255
#ifndef ETHERTYPE_MOPDL
5356
#define ETHERTYPE_MOPDL 0x6001
5457
#endif

‎gencode.c

+165
Original file line numberDiff line numberDiff line change
@@ -60,6 +60,8 @@
6060
#include "atmuni31.h"
6161
#include "sunatmpos.h"
6262
#include "ppp.h"
63+
#include "batadv_packet.h"
64+
#include "batadv_legacy_packet.h"
6365
#include "pcap/sll.h"
6466
#include "pcap/ipnet.h"
6567
#include "arcnet.h"
@@ -9483,6 +9485,169 @@ gen_geneve(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
94839485
return b1;
94849486
}
94859487

9488+
struct block *
9489+
gen_batadv_check_version(compiler_state_t *cstate, struct block *b0, bpf_u_int32 version)
9490+
{
9491+
struct block *b1;
9492+
9493+
if (version > UINT8_MAX)
9494+
bpf_error(cstate,
9495+
"batman-adv compatibility version number %u unsupported",
9496+
version);
9497+
9498+
b1 = gen_cmp(cstate, OR_LINKPL, 1, BPF_B, version);
9499+
gen_and(b0, b1);
9500+
9501+
return b1;
9502+
}
9503+
9504+
struct block *
9505+
gen_batadv_check_type(compiler_state_t *cstate, struct block *b0,
9506+
bpf_u_int32 version, bpf_u_int32 type)
9507+
{
9508+
struct block *b1;
9509+
9510+
switch (version) {
9511+
case 14:
9512+
case 15:
9513+
if (type > UINT8_MAX)
9514+
bpf_error(cstate,
9515+
"batman-adv packet type %u unsupported for compatibility version %u",
9516+
type, version);
9517+
9518+
b1 = gen_cmp(cstate, OR_LINKPL, 0, BPF_B, type);
9519+
gen_and(b0, b1);
9520+
b0 = b1;
9521+
9522+
break;
9523+
default:
9524+
bpf_error(cstate,
9525+
"batman-adv compatibility version number %u unsupported",
9526+
version);
9527+
}
9528+
9529+
return b0;
9530+
}
9531+
9532+
9533+
static void gen_batadv_push_offset(compiler_state_t *cstate, size_t offset)
9534+
{
9535+
PUSH_LINKHDR(cstate, DLT_EN10MB, cstate->off_linkpl.is_variable,
9536+
cstate->off_linkpl.constant_part + cstate->off_nl + offset,
9537+
cstate->off_linkpl.reg);
9538+
9539+
cstate->off_linktype.constant_part += cstate->off_linkhdr.constant_part;
9540+
cstate->off_linkpl.constant_part += cstate->off_linkhdr.constant_part;
9541+
9542+
cstate->off_nl = 0;
9543+
cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
9544+
}
9545+
9546+
static void
9547+
gen_batadv_offsets_v14(compiler_state_t *cstate, bpf_u_int32 type)
9548+
{
9549+
size_t offset;
9550+
9551+
switch (type) {
9552+
case BATADV_LEGACY_UNICAST: /* 0x03 */
9553+
offset = sizeof(struct batadv_legacy_unicast_packet);
9554+
break;
9555+
case BATADV_LEGACY_BCAST: /* 0x04 */
9556+
offset = sizeof(struct batadv_legacy_bcast_packet);
9557+
break;
9558+
case BATADV_LEGACY_UNICAST_FRAG: /* 0x06 */
9559+
offset = sizeof(struct batadv_legacy_unicast_frag_packet);
9560+
break;
9561+
case BATADV_LEGACY_UNICAST_4ADDR: /* 0x09 */
9562+
offset = sizeof(struct batadv_legacy_unicast_4addr_packet);
9563+
break;
9564+
case BATADV_LEGACY_CODED: /* 0x0a */
9565+
offset = sizeof(struct batadv_legacy_coded_packet);
9566+
break;
9567+
default:
9568+
offset = 0;
9569+
}
9570+
9571+
if (offset)
9572+
gen_batadv_push_offset(cstate, offset);
9573+
}
9574+
9575+
static void
9576+
gen_batadv_offsets_v15(compiler_state_t *cstate, bpf_u_int32 type)
9577+
{
9578+
size_t offset;
9579+
9580+
switch (type) {
9581+
case BATADV_BCAST: /* 0x01 */
9582+
offset = sizeof(struct batadv_bcast_packet);
9583+
break;
9584+
case BATADV_CODED: /* 0x02 */
9585+
offset = sizeof(struct batadv_coded_packet);
9586+
break;
9587+
case BATADV_UNICAST: /* 0x40 */
9588+
offset = sizeof(struct batadv_unicast_packet);
9589+
break;
9590+
case BATADV_UNICAST_FRAG: /* 0x41 */
9591+
offset = sizeof(struct batadv_frag_packet);
9592+
break;
9593+
case BATADV_UNICAST_4ADDR: /* 0x42 */
9594+
offset = sizeof(struct batadv_unicast_4addr_packet);
9595+
break;
9596+
case BATADV_UNICAST_TVLV:
9597+
/* unsupported for now, needs variable offset to
9598+
* take tvlv_len into account
9599+
*/
9600+
/* fall through */
9601+
default:
9602+
offset = 0;
9603+
}
9604+
9605+
if (offset)
9606+
gen_batadv_push_offset(cstate, offset);
9607+
}
9608+
9609+
static void
9610+
gen_batadv_offsets(compiler_state_t *cstate, bpf_u_int32 version, bpf_u_int32 type)
9611+
{
9612+
switch (version) {
9613+
case 14:
9614+
gen_batadv_offsets_v14(cstate, type);
9615+
break;
9616+
case 15:
9617+
gen_batadv_offsets_v15(cstate, type);
9618+
break;
9619+
default:
9620+
break;
9621+
}
9622+
}
9623+
9624+
struct block *
9625+
gen_batadv(compiler_state_t *cstate, bpf_u_int32 version, int has_version,
9626+
bpf_u_int32 type, int has_type)
9627+
{
9628+
struct block *b0, *b1;
9629+
struct slist *s;
9630+
9631+
/*
9632+
* Catch errors reported by us and routines below us, and return NULL
9633+
* on an error.
9634+
*/
9635+
if (setjmp(cstate->top_ctx))
9636+
return (NULL);
9637+
9638+
b0 = gen_linktype(cstate, ETHERTYPE_BATMAN);
9639+
9640+
if (has_version)
9641+
b0 = gen_batadv_check_version(cstate, b0, version);
9642+
9643+
if (has_type) {
9644+
b0 = gen_batadv_check_type(cstate, b0, version, type);
9645+
gen_batadv_offsets(cstate, version, type);
9646+
}
9647+
9648+
return b0;
9649+
}
9650+
94869651
/* Check that the encapsulated frame has a link layer header
94879652
* for Ethernet filters. */
94889653
static struct block *

‎gencode.h

+3
Original file line numberDiff line numberDiff line change
@@ -346,6 +346,9 @@ struct block *gen_pppoes(compiler_state_t *, bpf_u_int32, int);
346346

347347
struct block *gen_geneve(compiler_state_t *, bpf_u_int32, int);
348348

349+
struct block *gen_batadv(compiler_state_t *, bpf_u_int32, int,
350+
bpf_u_int32, int);
351+
349352
struct block *gen_atmfield_code(compiler_state_t *, int, bpf_u_int32,
350353
int, int);
351354
struct block *gen_atmtype_abbrev(compiler_state_t *, int);

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