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Receive signed ITS messages and forward each at its declared length

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Signed packets. A GeoNetworking Basic Header NextHeader of 2 means a
TS 103 097 (IEEE 1609.2) envelope follows, with the Common Header
inside it. gn_unwrap_its rejected all of these, and most real traffic is
signed: the 2026-08-17 capture holds 157 signed frames from 15 source
MACs against 2 unsecured stations. It now opens a COER-encoded
signedData, or a bare unsecuredData, and parses the inner packet as
before. The inner packet comes first inside tbsData, so the certificate
and signature are never parsed, and the signature is not verified - the
firmware has no trust store. Such messages reach the phone with the new
V2X_RX flags bit1, signed but not verified. The app reads only bit0 and
is unaffected until it learns the flag. Encrypted payloads, nested
signing and the legacy v1.2.1 envelope are still rejected. All 157
recorded signed frames have the layout this reads, in all three COER
length forms, and asn1tools decodes every envelope to the same inner
packet.

Payload bounds. Every frame recorded through the ESP32-C5's promiscuous
RX, about 15 000 of them, ends in 8 bytes that are not part of the
802.11 frame and not a valid FCS. obu-firmware reads frames through the
same API and took the rest of the frame as the message, so it forwarded
those 8 bytes to the phone after every message. UPER decoders stop where
the message ends, so nothing visibly broke, but the bytes cost serial
bandwidth and 8 bytes of the DENM's headroom, and they stayed attached
wherever raw payloads were stored or passed on. The payload is now
exactly what the Common Header's payload-length field declares, which is
also what separates a signed message from its signature.

A frame longer than main.c's 800-byte capture buffer is now reported as
truncated instead of being forwarded cut off, and counted as an oversize
drop through the new serial_link_note_oversize_drop, as it was when the
cut-off frame failed serial_link's size check.

Host tests in obu-firmware/test/host build the firmware sources
unmodified with MSYS2 gcc; `make` runs all three.
- test_chain: frames from the firmware's TX code checked byte by byte
  against EN 302 636-4-1 and parsed back, including hand-built signed
  frames, the payload-length rule, the RX trailer, and every truncation
  length against a no-access guard page. 1731 checks, 0 failures.
- test_replay and check_replay.py: all 15 145 recorded frames through
  gn_unwrap_its, cut to 800 bytes as on the board, and re-derived
  independently in Python with the envelope decoded by asn1tools. They
  agree on every record; 15 131 accepted, 157 of them signed. 11 043 of
  the 11 106 distinct messages re-encode byte-identically. The other 63
  fail the same way with the old 8 bytes put back, so the boundary is
  not the cause: 5 are our own CAMs from before the 2026-08-20
  yawRateConfidence fix, and the rest, from other stations, are a
  follow-up in TODO.md.
- fuzz_gn_unwrap: random edits of every recorded frame, each run against
  the guard page. 50 000 000 iterations, no crash.

obu-firmware/test/pcap_gn_tally.py tallies GeoNetworking header fields
per station over captures; it is how the other stations' lifetimes were
measured. TODO.md collects what is still open, including the on-air
check for this change: it builds on IDF 6.1 but has not been flashed.
This commit is contained in:
Ashin Walpola
2026-09-11 20:19:40 +02:00
parent 1baae2c5f6
commit 75d6d3b85c
15 changed files with 2196 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files
obu-firmware/test/host/Makefile
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# Host-side tests for obu-firmware. See README.md: needs gcc and make on PATH (MSYS2 UCRT64), and
# asn1tools under `py -3.11` for the replay check.
#
# make build and run everything: chain, replay, fuzz
# make chain | replay | fuzz one of them
# make fuzz FUZZ_ITER=50000000 FUZZ_SEED=7 a longer or different fuzz run
# make clean remove build/
#
# The firmware sources are compiled straight from ../../main, never copied.
CC = gcc
PYTHON = python
PYTHON_ASN1 = py -3.11
FW = ../../main
BUILD = build
EXE = $(if $(filter Windows_NT,$(OS)),.exe,)
RECORDINGS = $(wildcard ../../../its-g5-receiver-firmware/recordings/*.pcap)
FUZZ_ITER = 2000000
FUZZ_SEED = 1
# -Werror: these sources must stay warning-free on the host compiler too.
# UBSan in trap mode needs no runtime library, so it works on MinGW; a trap shows up as a crash.
CFLAGS = -std=c11 -O2 -g -Wall -Wextra -Wpedantic -Werror -I$(FW) \
-fsanitize=undefined -fsanitize-undefined-trap-on-error
FW_SRCS = $(FW)/geonet.c $(FW)/dot11p.c $(FW)/gn_unwrap.c
DEPS = test_util.c test_util.h $(FW_SRCS) $(wildcard $(FW)/*.h)
.PHONY: all check chain replay fuzz clean
all: check
check: chain replay fuzz
$(BUILD):
mkdir -p $@
$(BUILD)/%$(EXE): %.c $(DEPS) | $(BUILD)
$(CC) $(CFLAGS) -o $@ $< test_util.c $(FW_SRCS)
# The pcap goes through pcap_gn_tally.py as a second, independent parser of the same frames.
chain: $(BUILD)/test_chain$(EXE)
$(BUILD)/test_chain$(EXE) $(BUILD)/test_chain.pcap
$(PYTHON) ../pcap_gn_tally.py $(BUILD)/test_chain.pcap
replay: $(BUILD)/test_replay$(EXE)
ifeq ($(RECORDINGS),)
@echo "replay: no recordings in ../../../its-g5-receiver-firmware/recordings, skipped"
else
$(BUILD)/test_replay$(EXE) $(BUILD)/replay.tsv $(RECORDINGS)
$(PYTHON_ASN1) check_replay.py $(BUILD)/replay.tsv $(RECORDINGS)
endif
fuzz: $(BUILD)/fuzz_gn_unwrap$(EXE)
$(BUILD)/fuzz_gn_unwrap$(EXE) $(FUZZ_ITER) $(FUZZ_SEED) $(RECORDINGS)
clean:
rm -rf $(BUILD)
obu-firmware/test/host/README.md
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# Host-side tests for obu-firmware
**Status (2026-09-11):** the chain test, the capture replay and the fuzzer are written and pass;
results under "Running". Toolchain: MSYS2 UCRT64 gcc, Option B below (chosen and
installed 2026-09-11).
`geonet.c`, `dot11p.c` and `gn_unwrap.c` include nothing but standard C headers, so they compile
unmodified on a PC. That makes three things possible without a board: a TX -> RX round trip
through our own code, replaying real captures through the RX parser, and fuzzing the parser that
reads untrusted radio bytes. ESP-IDF only builds `main/` (and `components/`), so nothing under
`test/` ever affects the firmware image.
## Layout
```
obu-firmware/
├── main/ firmware sources; the tests compile these directly, never copies
└── test/
├── pcap_gn_tally.py GN header fields per station over .pcap captures (Python only)
└── host/
├── README.md this file
├── Makefile `make`: builds ../../main/{geonet,dot11p,gn_unwrap}.c + tests, runs them
├── test_chain.c geonet_wrap_shb -> dot11p_build_frame -> gn_unwrap_its, byte-checked
├── test_util.c/.h shared: guard page, crash report, pcap read/write
├── test_replay.c every recorded frame through gn_unwrap_its, results to a TSV
├── check_replay.py re-derives each result independently, then asn1tools on the messages
├── fuzz_gn_unwrap.c mutation fuzzer; each input ends against a no-access guard page, so
│ an over-read faults (no ASan on MinGW)
└── build/ compiler output; already ignored by the repo's `build/` rule
```
The repo's `vanetza/` folder is a gitignored reading copy only; it is not built. `check_replay.py`
reads the IEEE 1609.2 ASN.1 modules from it (they carry no licence header, so they are not copied
into `asn1/`). Without it, signed frames are still replayed but not checked independently.
## Running
From PowerShell, with MSYS2 on PATH for the session (Option B step 3):
```powershell
$env:PATH = "C:\msys64\ucrt64\bin;C:\msys64\usr\bin;$env:PATH"
cd C:\Users\Ashin\AndroidStudioProjects\MicrOBU\obu-firmware\test\host
make
```
`make` runs three things (`make chain`, `make replay`, `make fuzz` run one). A non-zero exit, or a
`CRASH ... during: <what>` line (from the fuzzer, followed by the input as hex), is a failure.
- **chain** (`test_chain.c`): frames built by the firmware's own TX code, checked byte by byte
against EN 302 636-4-1 and parsed back. Covers the CAM layout (non-QoS and QoS), Source Position
Vector edges, output-buffer bounds, a 512-byte payload through `main.c`'s buffer sizes,
hand-built GeoBroadcast frames in all three shapes, signed frames in all three COER length
forms plus a top-level unsecuredData, one-byte mutations that must be rejected or accepted, the
Common Header's payload length as the message boundary, the 8-byte RX trailer, and every
truncation length of each frame against the guard page. `pcap_gn_tally.py` then reads the
frames back as a second parser; `build/test_chain.pcap` opens in Wireshark too.
2026-09-11: 1731 checks, 0 failed.
- **replay** (`test_replay.c` + `check_replay.py`): every record in
`its-g5-receiver-firmware/recordings/*.pcap` through `gn_unwrap_its`, each cut to `main.c`'s
800-byte capture buffer as on the board. `check_replay.py` re-derives each result on its own
(its own GN/BTP parse; the security envelope decoded by asn1tools from the IEEE 1609.2 modules),
compares record by record, then decodes and re-encodes every distinct message with asn1tools -
a byte-identical re-encode is only possible when the message was cut at exactly the right byte.
Needs `py -3.11` with asn1tools. 2026-09-11: 15 145 records, 15 131 accepted (10 831 CAM,
4 300 DENM; 157 of them signed); C and Python agree on every record; 11 043 of the 11 106
distinct messages re-encode byte-identically. The other 63 fail the same way with the old 8
trailing bytes put back, so the boundary is not the cause: 5 are our own CAMs from before the
2026-08-20 yawRateConfidence fix, 56 come from the CiT One and 1 from another station (see
`TODO.md`), and 1 uses an extension asn1tools cannot re-encode.
- **fuzz** (`fuzz_gn_unwrap.c`): random edits of every recorded frame, each run against the guard
page; an over-read crashes, an accepted payload outside its input fails. Default 2 000 000
iterations (about 2 s); `make fuzz FUZZ_ITER=50000000 FUZZ_SEED=7` for a longer run.
2026-09-11: 50 000 000 iterations, no crash.
Not covered: `main.c` (serial prefix parsing, queues) and `serial_link.c`, which need ESP-IDF;
and the phone's encoder, whose bytes are opaque here (asn1tools and the app's golden test cover
it).
## Option A (not used): WSL2 + Ubuntu 24.04
Kept as the fallback if AddressSanitizer or libFuzzer are ever needed; Option B has neither.
1. In **PowerShell as Administrator**:
```powershell
wsl --install -d Ubuntu-24.04
```
Reboot if it asks. Ubuntu then opens and asks for a Linux username and password (separate from
the Windows account). Checked 2026-09-11: Hyper-V is already running on this PC, so no BIOS
change should be needed. If the install says virtualization is disabled, enable Intel VT-x /
AMD SVM in the BIOS.
2. Confirm it is WSL **2**: `wsl -l -v` should list `Ubuntu-24.04` with VERSION `2`.
3. Inside Ubuntu, the compilers:
```bash
sudo apt update
sudo apt install -y build-essential clang cmake ninja-build git pkg-config python3
```
4. Smoke test: the firmware sources compile on the host (expect no output):
```bash
cd /mnt/c/Users/Ashin/AndroidStudioProjects/MicrOBU/obu-firmware/test/host
cc -std=c11 -Wall -Wextra -fsyntax-only ../../main/geonet.c ../../main/dot11p.c ../../main/gn_unwrap.c
```
## Option B (chosen): native Windows gcc via MSYS2
Enough for the round-trip test, the capture replay and the guard-page fuzzer. No libFuzzer and no
AddressSanitizer with MinGW gcc, which is why the fuzzer uses a guard page instead.
1. In PowerShell: `winget install -e --id MSYS2.MSYS2` (installs to `C:\msys64`).
2. Open **MSYS2 UCRT64** from the Start menu and run `pacman -Syu`. If the window closes, reopen
it and run `pacman -Syu` again. Then:
```bash
pacman -S --needed mingw-w64-ucrt-x86_64-gcc make
```
3. **`C:\msys64\ucrt64\bin` must be on PATH.** Calling `C:\msys64\ucrt64\bin\gcc.exe` by its full
path alone exits 1 with no message, because gcc's compiler stages load their DLLs from that
folder. `make` lives on the MSYS side, in `C:\msys64\usr\bin`. Either work inside the
**MSYS2 UCRT64** shell, which has both, or put them on PATH for the current session:
```powershell
$env:PATH = "C:\msys64\ucrt64\bin;C:\msys64\usr\bin;$env:PATH" # PowerShell
```
```bash
export PATH=/c/msys64/ucrt64/bin:/c/msys64/usr/bin:$PATH # Git Bash
```
Adding them to the user PATH permanently also works; it was deliberately not done by setup.
4. Smoke test (expect no output):
```powershell
cd C:\Users\Ashin\AndroidStudioProjects\MicrOBU\obu-firmware\test\host
gcc -std=c11 -Wall -Wextra -fsyntax-only ../../main/geonet.c ../../main/dot11p.c ../../main/gn_unwrap.c
```
Installed on this PC 2026-09-11: MSYS2 20260611, gcc 16.2.0 (UCRT64), GNU Make 4.4.1. All three
firmware sources compile with `-std=c11 -O2 -Wall -Wextra -Wpedantic` and no warnings.
## Line endings
The repo runs with `core.autocrlf=true`, so Windows checkouts have CRLF line endings. C compilers
don't care; shell scripts run from WSL do (`bash: $'\r': command not found`). When the first `.sh`
file lands here, add `*.sh text eol=lf` to a root `.gitattributes` (none exists yet).
obu-firmware/test/host/check_replay.py
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#!/usr/bin/env python3
"""Independent check of test_replay's output. See README.md.
For every recorded frame this works out on its own what gn_unwrap_its should have produced -
GeoNetworking and BTP parsed here from EN 302 636-4-1, the TS 103 097 security envelope decoded by
asn1tools from the IEEE 1609.2 ASN.1 modules rather than by hand - and compares that with what the
C code did, record by record. Then it decodes every distinct extracted message with asn1tools and
re-encodes it. Only a message cut at exactly the right byte re-encodes to the same bytes, so this
is what proves that no trailer or signature bytes came along with it.
py -3.11 check_replay.py replay.tsv capture.pcap [capture.pcap ...]
Needs asn1tools (installed for Python 3.11 on this PC). Message modules come from the repo's
asn1/; the IEEE 1609.2 ones from asn1/ or, failing that, the gitignored vanetza/ checkout.
Exit status 1 if the C code and this disagree about any record.
"""
import collections
import pathlib
import struct
import sys
import asn1tools
ROOT = pathlib.Path(__file__).resolve().parents[3]
PORT_NAMES = {2001: "CAM", 2002: "DENM", 2004: "SPATEM"}
# main.c's RX_FRAME_MAX_LEN: the most of any frame the board hands to gn_unwrap_its. test_replay
# cuts frames to it, so this does too.
RX_FRAME_MAX_LEN = 800
def compile_specs():
a = ROOT / "asn1"
uper = {
2001: asn1tools.compile_files([str(a / "cam_1_4_1.asn"), str(a / "cdd_1_3_1_1.asn")], "uper"),
2002: asn1tools.compile_files([str(a / "denm_1_3_1.asn"), str(a / "cdd_1_3_1_1.asn")], "uper"),
2004: asn1tools.compile_files(
[str(a / n) for n in ("spatem_2_2_1.asn", "mapem_2_2_1.asn", "dsrc_2_2_1.asn", "cdd_2_2_1.asn")],
"uper"),
}
names = ("IEEE1609dot2BaseTypes.asn", "IEEE1609dot2.asn")
for d in (a, ROOT / "vanetza" / "asn1"):
if all((d / n).exists() for n in names):
return uper, asn1tools.compile_files([str(d / n) for n in names], "oer"), d
return uper, None, None
def frames(path):
"""(record index, 802.11 frame) for every record, numbered the way test_util.c numbers them."""
d = pathlib.Path(path).read_bytes()
if len(d) < 24:
return
magic = struct.unpack("<I", d[:4])[0]
e = "<" if magic in (0xA1B2C3D4, 0xA1B23C4D) else ">"
link = struct.unpack(e + "I", d[20:24])[0]
if link not in (105, 127):
return
off, index = 24, 0
while off + 16 <= len(d):
incl = struct.unpack(e + "I", d[off + 8:off + 12])[0]
if incl > len(d) - off - 16:
break
pkt = d[off + 16:off + 16 + incl]
off += 16 + incl
if link == 127:
rl = pkt[2] | pkt[3] << 8 if len(pkt) >= 4 else len(pkt) + 1
if rl > len(pkt):
index += 1
continue
pkt = pkt[rl:]
yield index, pkt
index += 1
def open_envelope(sec, env):
"""(inner GeoNetworking packet, signed) of a TS 103 097 envelope per asn1tools, or None."""
try:
m = sec.decode("Ieee1609Dot2Data", env)
except Exception:
return None
if m["protocolVersion"] != 3:
return None
kind, content = m["content"]
if kind == "unsecuredData":
return content, False
if kind == "signedData":
data = content["tbsData"]["payload"].get("data")
if data and data["protocolVersion"] == 3 and data["content"][0] == "unsecuredData":
return data["content"][1], True
return None
def u16(b):
return int.from_bytes(b, "big")
def s32(b):
return int.from_bytes(b, "big", signed=True)
def expect(f, sec):
"""What gn_unwrap_its should report for frame f: None, or a dict matching test_replay's row.
Second value: how many bytes after the message the pre-2026-09-11 code would have forwarded."""
if len(f) < 24 or (f[0] >> 2) & 3 != 2 or f[1] & 3 == 3:
return None, None
o = 24 + (2 if f[0] & 0x80 else 0)
if f[o:o + 8] != b"\xaa\xaa\x03\x00\x00\x00\x89\x47" or len(f) < o + 12:
return None, None
nh = f[o + 8] & 0x0F
o += 12
if nh == 2:
if sec is None:
return "unchecked", None
opened = open_envelope(sec, f[o:])
if opened is None:
return None, None
region, signed = opened
elif nh == 1:
region, signed = f[o:], False
else:
return None, None
if len(region) < 8 or region[0] >> 4 != 2:
return None, None
ht, hst, pl = region[1] >> 4, region[1] & 0x0F, u16(region[4:6])
if ht == 5 and hst == 0:
ext, area = 28, None
elif ht == 4:
ext = 44
else:
return None, None
if len(region) < 8 + ext + 4:
return None, None
if ht == 4:
a = 8 + 28
area = (s32(region[a:a + 4]), s32(region[a + 4:a + 8]), u16(region[a + 8:a + 10]))
port = u16(region[8 + ext:8 + ext + 2])
if port not in PORT_NAMES or pl <= 4:
return None, None
start, end = 8 + ext + 4, 8 + ext + pl
if signed is not None and nh == 2 and end > len(region):
return None, None # the inner packet claims more than its envelope holds
payload = region[start:min(end, len(region))]
if not payload:
return None, None
old_extra = len(region) - end if nh == 1 else None
return dict(port=port, signed=signed, truncated=end > len(region), area=area, payload=payload), old_extra
def read_tsv(path):
rows = {}
with open(path, encoding="ascii") as fh:
next(fh)
for line in fh:
c = line.rstrip("\n").split("\t")
key = (c[0], int(c[1]))
if c[2] == "0":
rows[key] = None
else:
rows[key] = dict(port=int(c[3]), signed=c[4] == "1", truncated=c[5] == "1",
area=(int(c[7]), int(c[8]), int(c[9])) if c[6] == "1" else None,
payload=bytes.fromhex(c[10]))
return rows
def describe(r):
if r is None:
return "rejected"
return "port %d signed %s truncated %s area %s %d bytes" % (
r["port"], r["signed"], r["truncated"], r["area"], len(r["payload"]))
def main(argv):
if len(argv) < 2:
sys.exit(__doc__)
got = read_tsv(argv[0])
uper, sec, sec_dir = compile_specs()
if sec is None:
print("WARNING: IEEE 1609.2 modules not found; secured frames are not checked independently")
stats, extra, disagreements, messages = collections.Counter(), collections.Counter(), [], {}
for path in argv[1:]:
for index, f in frames(path):
key = (path, index)
stats["records"] += 1
stats["capped"] += len(f) > RX_FRAME_MAX_LEN
want, old_extra = expect(f[:RX_FRAME_MAX_LEN], sec)
if key not in got:
disagreements.append((key, "no row from test_replay"))
continue
have = got.pop(key)
if want == "unchecked":
stats["secured, unchecked"] += 1
continue
if want != have:
disagreements.append((key, "C: %s | independent: %s" % (describe(have), describe(want))))
continue
if want:
stats["accepted"] += 1
stats[PORT_NAMES[want["port"]]] += 1
stats["signed"] += want["signed"]
stats["truncated"] += want["truncated"]
if old_extra is not None:
extra[old_extra] += 1
messages.setdefault((want["port"], want["payload"]), key)
for key in got:
disagreements.append((key, "row from test_replay for a record this did not see"))
print("check_replay: %d records (%d cut to %d bytes), %d accepted (CAM %d, DENM %d, SPATEM %d; "
"%d signed, %d truncated)"
% (stats["records"], stats["capped"], RX_FRAME_MAX_LEN, stats["accepted"], stats["CAM"],
stats["DENM"], stats["SPATEM"], stats["signed"], stats["truncated"]))
if sec_dir:
print(" envelopes decoded with asn1tools using %s" % sec_dir.relative_to(ROOT))
print(" C vs independent parse: %s" % ("agree on every record" if not disagreements
else "%d DISAGREEMENTS" % len(disagreements)))
for key, why in disagreements[:15]:
print(" %s record %d: %s" % (pathlib.Path(key[0]).name, key[1], why))
outcome, failures = collections.Counter(), []
for (port, payload), key in messages.items():
name, spec = PORT_NAMES[port], uper[port]
try:
decoded = spec.decode(name, payload)
except Exception as e:
outcome[(name, "does not decode")] += 1
failures.append((key, name, len(payload), str(e)[:110]))
continue
try:
encoded = spec.encode(name, decoded)
except Exception as e:
# asn1tools decodes an alternative from a later module version (a CHOICE extension)
# as (None, None) and then cannot encode it back. Says nothing about where the message
# was cut, so it is reported apart from real mismatches.
outcome[(name, "decodes; uses a newer extension")] += 1
failures.append((key, name, len(payload), "cannot re-encode: " + str(e)[:90]))
continue
if encoded == payload:
outcome[(name, "re-encodes byte-identically")] += 1
else:
outcome[(name, "re-encodes differently")] += 1
failures.append((key, name, len(payload), "re-encoded to different bytes"))
print(" asn1tools on the %d distinct extracted messages:" % len(messages))
for (name, what), n in sorted(outcome.items()):
print(" %-6s %-28s %d" % (name, what, n))
for key, name, n, why in failures[:15]:
print(" %s record %d, %s %d bytes: %s" % (pathlib.Path(key[0]).name, key[1], name, n, why))
print(" bytes the pre-2026-09-11 code forwarded after each unsecured message: %s"
% dict(sorted(extra.items())))
return 1 if disagreements else 0
if __name__ == "__main__":
sys.exit(main(sys.argv[1:]))
obu-firmware/test/host/fuzz_gn_unwrap.c
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// Mutation fuzzer for gn_unwrap_its, the one function in this firmware that parses bytes from the
// air. See README.md.
//
// Seeds are every recorded frame in the pcaps given, plus frames built by the firmware's own TX
// code. Each iteration takes a seed, applies 1-4 random edits - bit flips, random bytes, boundary
// bytes such as COER length markers, 16-bit length fields, truncation, insertion, deletion,
// appended bytes - mostly within the first 128 bytes where the headers are, and runs gn_unwrap_its
// on the result placed against the guard page. A read past the end crashes and prints the input;
// an accepted frame whose payload is not inside the input is reported the same way. MinGW has
// neither libFuzzer nor AddressSanitizer, hence this rather than coverage guidance. The same seed
// gives the same run.
//
// Usage: fuzz_gn_unwrap iterations seed [capture.pcap ...]
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dot11p.h"
#include "geonet.h"
#include "gn_unwrap.h"
#include "test_util.h"
#define MAX_FRAME 2048 // within the guard page's one page, and above any 802.11 frame
static uint8_t **s_seeds;
static int *s_seed_len;
static int s_nseeds;
static int s_seed_cap;
static void add_seed(const uint8_t *f, int len)
{
if (len <= 0 || len > MAX_FRAME) {
return;
}
if (s_nseeds == s_seed_cap) {
s_seed_cap = s_seed_cap ? 2 * s_seed_cap : 1024;
s_seeds = realloc(s_seeds, (size_t)s_seed_cap * sizeof *s_seeds);
s_seed_len = realloc(s_seed_len, (size_t)s_seed_cap * sizeof *s_seed_len);
if (!s_seeds || !s_seed_len) {
fprintf(stderr, "out of memory\n");
exit(2);
}
}
s_seeds[s_nseeds] = malloc((size_t)len);
if (!s_seeds[s_nseeds]) {
fprintf(stderr, "out of memory\n");
exit(2);
}
memcpy(s_seeds[s_nseeds], f, (size_t)len);
s_seed_len[s_nseeds++] = len;
}
static void on_frame(const uint8_t *f, int len, int index, void *ctx)
{
(void)index;
(void)ctx;
add_seed(f, len);
}
static void add_own_seeds(void)
{
static const uint8_t cam[] = {0x02, 0x02, 0x00, 0x0f, 0x42, 0x3f, 0x37, 0x00, 0x40, 0x2a, 0xb2};
gn_lpv_t lpv;
memset(&lpv, 0, sizeof lpv);
lpv.mac[0] = 0x02;
lpv.station_type = 2;
uint8_t gn[256];
uint8_t f[512];
const int gn_len = geonet_wrap_shb(cam, (int)sizeof cam, &lpv, 2001, gn, sizeof gn);
for (int qos = 0; qos <= 1; qos++) {
add_seed(f, dot11p_build_frame(gn, gn_len, lpv.mac, f, sizeof f, qos));
}
}
static uint64_t s_rng;
static uint64_t rnd(void)
{
s_rng ^= s_rng << 13;
s_rng ^= s_rng >> 7;
s_rng ^= s_rng << 17;
return s_rng;
}
static int below(int n)
{
return n <= 0 ? 0 : (int)(rnd() % (uint64_t)n);
}
// Three times in four inside the headers, otherwise anywhere.
static int pick_pos(int len)
{
return below(4) ? below(len < 128 ? len : 128) : below(len);
}
static const uint8_t k_bytes[] = {0x00, 0x01, 0x02, 0x03, 0x05, 0x10, 0x12, 0x20,
0x40, 0x50, 0x7F, 0x80, 0x81, 0x82, 0x83, 0xFF};
static const uint16_t k_words[] = {0x0000, 0x0001, 0x0003, 0x0004, 0x0005, 0x007F,
0x0080, 0x00FF, 0x0100, 0x7FFF, 0x8000, 0xFFFF};
static void mutate(uint8_t *b, int *len)
{
const int edits = 1 + below(4);
for (int e = 0; e < edits; e++) {
const int n = *len;
switch (below(8)) {
case 0: // flip a bit
if (n) {
b[pick_pos(n)] ^= (uint8_t)(1u << below(8));
}
break;
case 1: // random byte
if (n) {
b[pick_pos(n)] = (uint8_t)rnd();
}
break;
case 2: // boundary byte
if (n) {
b[pick_pos(n)] = k_bytes[below((int)sizeof k_bytes)];
}
break;
case 3: // truncate
*len = below(n + 1);
break;
case 4: { // append
const int add = 1 + below(16);
if (n + add <= MAX_FRAME) {
for (int i = 0; i < add; i++) {
b[n + i] = (uint8_t)rnd();
}
*len = n + add;
}
break;
}
case 5: // insert a byte
if (n < MAX_FRAME) {
const int p = below(n + 1);
memmove(b + p + 1, b + p, (size_t)(n - p));
b[p] = (uint8_t)rnd();
*len = n + 1;
}
break;
case 6: // delete a byte
if (n) {
const int p = below(n);
memmove(b + p, b + p + 1, (size_t)(n - p - 1));
*len = n - 1;
}
break;
default: // boundary 16-bit big-endian value, e.g. a length field
if (n >= 2) {
const int p = pick_pos(n - 1);
const uint16_t v = k_words[below((int)(sizeof k_words / sizeof k_words[0]))];
b[p] = (uint8_t)(v >> 8);
b[p + 1] = (uint8_t)v;
}
break;
}
}
}
int main(int argc, char **argv)
{
if (argc < 3) {
fprintf(stderr, "usage: fuzz_gn_unwrap iterations seed [capture.pcap ...]\n");
return 2;
}
const unsigned long long iterations = strtoull(argv[1], NULL, 10);
s_rng = (strtoull(argv[2], NULL, 10) * 0x9E3779B97F4A7C15ull) | 1;
tu_install_crash_handler();
tu_guard_init();
for (int i = 3; i < argc; i++) {
if (tu_pcap_foreach(argv[i], on_frame, NULL) < 0) {
fprintf(stderr, "cannot read %s as a pcap\n", argv[i]);
return 2;
}
}
add_own_seeds();
static uint8_t buf[MAX_FRAME];
int len = 0;
tu_set_crash_input(buf, &len);
unsigned long long accepted = 0, signed_frames = 0, truncated = 0;
for (unsigned long long it = 0; it < iterations; it++) {
const int s = below(s_nseeds);
len = s_seed_len[s];
memcpy(buf, s_seeds[s], (size_t)len);
mutate(buf, &len);
tu_set_context("fuzz iteration %llu (seed %s), mutated from seed frame %d", it, argv[2], s);
const uint8_t *g = tu_guarded(buf, len);
gn_rx_t rx;
if (gn_unwrap_its(g, len, &rx)) {
accepted++;
signed_frames += rx.signed_unverified;
truncated += rx.truncated;
const uintptr_t lo = (uintptr_t)g;
const uintptr_t p = (uintptr_t)rx.payload;
if (p < lo || rx.payload_len <= 0 || p + (uintptr_t)rx.payload_len > lo + (uintptr_t)len) {
fprintf(stderr, "FAIL during %s: accepted payload lies outside the input\ninput (%d bytes): ",
tu_context(), len);
for (int i = 0; i < len; i++) {
fprintf(stderr, "%02x", buf[i]);
}
fputc('\n', stderr);
return 1;
}
}
}
printf("fuzz_gn_unwrap: %llu iterations from %d seed frames, %llu accepted (%llu signed, "
"%llu truncated), no crash\n",
iterations, s_nseeds, accepted, signed_frames, truncated);
return 0;
}
obu-firmware/test/host/test_chain.c
+730
View File
@@ -0,0 +1,730 @@
// Host-side chain test for obu-firmware. See README.md in this folder.
//
// Builds frames with the firmware's own TX code (geonet_wrap_shb -> dot11p_build_frame) and parses
// them back with its own RX code (gn_unwrap_its), all compiled from ../../main unmodified.
//
// Two kinds of check, on purpose. The round trip proves TX and RX agree with each other. The byte
// checks at fixed offsets prove they agree with EN 302 636-4-1, and only those catch a mistake made
// the same way on both sides: the missing 4-byte SHB field (fixed 2026-08-13) round-tripped fine
// between two ESP32s and was wrong against every other station. So expected values here come from
// the standard, vanetza's serializers and real captures - never from reading geonet.c.
//
// Every frame handed to gn_unwrap_its is first copied so that its last byte sits right before a
// no-access page (test_util.c): reading even one byte past a frame crashes the test instead of
// passing quietly. MinGW has no AddressSanitizer; this covers what matters for a radio parser.
//
// Usage: test_chain [out.pcap]
// With a path, also writes every test frame to a pcap (linktype 105, bare 802.11) so a second,
// independent parser can read them: ../pcap_gn_tally.py, or Wireshark. The GeoBroadcast and
// signed frames carry stub payloads/signatures; their headers are real.
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dot11p.h"
#include "geonet.h"
#include "gn_unwrap.h"
#include "serial_link.h" // SERIAL_LINK_MAX_PAYLOAD only; serial_link.c itself needs ESP-IDF
#include "test_util.h"
// Same buffer sizes as tx_radio_task in main.c. Keep them in step with it.
#define GN_BUF_LEN (SERIAL_LINK_MAX_PAYLOAD + 64)
#define FRAME_BUF_LEN (SERIAL_LINK_MAX_PAYLOAD + 192)
// ---- Checks ---------------------------------------------------------------------------------
static int s_checks;
static int s_failures;
static void check(bool ok, int line, const char *fmt, ...)
{
s_checks++;
if (ok) {
return;
}
s_failures++;
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "FAIL line %d [%s]: ", line, tu_context());
vfprintf(stderr, fmt, ap);
fputc('\n', stderr);
va_end(ap);
}
#define CHECK(cond, ...) check((cond), __LINE__, __VA_ARGS__)
// ---- Test data ------------------------------------------------------------------------------
static uint16_t rd16(const uint8_t *p)
{
return (uint16_t)((p[0] << 8) | p[1]);
}
static uint32_t rd32(const uint8_t *p)
{
return ((uint32_t)p[0] << 24) | ((uint32_t)p[1] << 16) | ((uint32_t)p[2] << 8) | p[3];
}
// The app's reference CAM: the expected bytes of CamEncodeGoldenTest.kt (stationID 999999), which
// asn1tools decodes and re-encodes byte-identically. The chain treats it as opaque bytes. Not taken
// from the old captures on purpose: our own CAMs there predate the 2026-08-20 yawRateConfidence fix
// and do not decode.
static const uint8_t k_cam[] = {
0x02, 0x02, 0x00, 0x0f, 0x42, 0x3f, 0x37, 0x00, 0x40, 0x2a, 0xb2, 0x15, 0xaf, 0x6e, 0x28, 0x64,
0x77, 0xdf, 0xff, 0xff, 0xfc, 0x23, 0xb7, 0x74, 0x3e, 0x00, 0x27, 0xff, 0xc0, 0xd0, 0xfe, 0x01,
0x18, 0x32, 0x93, 0x37, 0xfe, 0xeb, 0xff, 0xf6, 0x00, 0x00, 0x00,
};
#define CAM_LEN ((int)sizeof k_cam)
static const uint8_t k_mac[6] = {0x02, 0x11, 0x22, 0x33, 0x44, 0x55};
static const uint8_t k_bcast[6] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
static const uint8_t k_llc_snap_gn[8] = {0xAA, 0xAA, 0x03, 0x00, 0x00, 0x00, 0x89, 0x47};
// The 8 bytes that follow the 802.11 frame in every frame recorded through the ESP32-C5's
// promiscuous RX (these from capture_20260817_171055.pcap). See gn_unwrap.h, "Payload bounds".
static const uint8_t k_rx_trailer[8] = {0xc8, 0x01, 0x00, 0x00, 0x88, 0x00, 0x00, 0x00};
// Header lengths from EN 302 636-4-1 / IEEE 802.11, used to compute every offset below.
enum {
MAC_HDR = 24, QOS_CTRL = 2, LLC_SNAP = 8, GN_BASIC = 4, GN_COMMON = 8,
SHB_EXT = 28, // Source Position Vector (24) + DCC-MCO / reserved (4)
GBC_EXT = 44, // SN (2) + reserved (2) + SO PV (24) + area (12) + reserved (4)
BTP_B = 4,
GN_COMMON_PAYLOAD_LEN_FIELD = 4, // offset of the payload-length field in the Common Header
};
// Where the ITS payload starts in a non-QoS SHB frame.
#define SHB_PAYLOAD_OFFSET (MAC_HDR + LLC_SNAP + GN_BASIC + GN_COMMON + SHB_EXT + BTP_B)
static gn_lpv_t test_lpv(void)
{
gn_lpv_t lpv;
memset(&lpv, 0, sizeof lpv);
memcpy(lpv.mac, k_mac, sizeof lpv.mac);
lpv.station_type = 2; // cyclist
lpv.pai = true;
lpv.tst_ms = 0x89ABCDEFu;
lpv.lat_tenmicrodeg = 535546667; // the bench, 53.5546667 N
lpv.lon_tenmicrodeg = -10022389; // negative on purpose: the sign has to survive
lpv.speed_cms = 1234;
lpv.heading_decideg = 2700;
return lpv;
}
// The TX path exactly as tx_radio_task runs it. Returns the frame length, or <= 0 on failure.
static int build(const uint8_t *payload, int len, const gn_lpv_t *lpv, uint16_t port, bool qos,
uint8_t *frame, size_t frame_size)
{
static uint8_t gn[GN_BUF_LEN];
int gn_len = geonet_wrap_shb(payload, len, lpv, port, gn, sizeof gn);
if (gn_len <= 0) {
return gn_len;
}
return dot11p_build_frame(gn, gn_len, lpv->mac, frame, frame_size, qos);
}
// Every prefix of a frame, each ending against the guard page. Up to the end of the BTP-B header
// nothing may be accepted; a frame cut inside the payload is accepted as truncated with what
// arrived; from `payload_end` on, the payload is exactly the declared one whatever follows it.
static void sweep(const char *name, const uint8_t *f, int len, int payload_start, int payload_end)
{
for (int n = 0; n <= len; n++) {
tu_set_context("truncation sweep, %s, %d of %d bytes", name, n, len);
const uint8_t *g = tu_guarded(f, n);
gn_rx_t rx;
const bool ok = gn_unwrap_its(g, n, &rx);
if (n <= payload_start) {
CHECK(!ok, "%s cut to %d bytes was accepted", name, n);
} else if (n < payload_end) {
CHECK(ok && rx.truncated && rx.payload == g + payload_start &&
rx.payload_len == n - payload_start,
"%s cut to %d bytes: ok=%d truncated=%d payload_len=%d", name, n, ok,
ok && rx.truncated, ok ? rx.payload_len : -1);
} else {
CHECK(ok && !rx.truncated && rx.payload == g + payload_start &&
rx.payload_len == payload_end - payload_start,
"%s at %d bytes: ok=%d truncated=%d payload_len=%d", name, n, ok,
ok && rx.truncated, ok ? rx.payload_len : -1);
}
}
}
// ---- SHB: layout, position vector, bounds ---------------------------------------------------
// Every byte of a CAM frame against the standard, then back through the RX path.
static void test_shb_layout(bool qos)
{
tu_set_context("SHB layout, qos=%d", qos);
const gn_lpv_t lpv = test_lpv();
uint8_t f[FRAME_BUF_LEN];
const int len = build(k_cam, CAM_LEN, &lpv, 2001, qos, f, sizeof f);
const int llc = MAC_HDR + (qos ? QOS_CTRL : 0);
const int basic = llc + LLC_SNAP;
const int common = basic + GN_BASIC;
const int shb = common + GN_COMMON;
const int btp = shb + SHB_EXT;
const int pay = btp + BTP_B;
CHECK(len == pay + CAM_LEN, "frame length %d, expected %d", len, pay + CAM_LEN);
if (len != pay + CAM_LEN) {
return;
}
// 802.11 MAC header
CHECK(f[0] == (qos ? 0x88 : 0x08) && f[1] == 0x00, "frame control %02x %02x", f[0], f[1]);
CHECK(memcmp(f + 4, k_bcast, 6) == 0, "addr1 must be broadcast");
CHECK(memcmp(f + 10, k_mac, 6) == 0, "addr2 must be the pseudonym");
CHECK(memcmp(f + 16, k_bcast, 6) == 0, "addr3 (BSSID) must be the OCB wildcard");
if (qos) {
CHECK(f[24] == 0 && f[25] == 0, "QoS control %02x %02x", f[24], f[25]);
}
CHECK(memcmp(f + llc, k_llc_snap_gn, 8) == 0, "LLC/SNAP with EtherType 0x8947");
// GN Basic Header
CHECK(f[basic + 0] == 0x11, "basic: version 1 + NextHeader 1 (Common, unsecured), got %02x",
f[basic + 0]);
CHECK(f[basic + 1] == 0x00, "basic: reserved, got %02x", f[basic + 1]);
// Multiplier 1 in the upper 6 bits, base 1 (= 1 s) in the lower 2: 1 s, what every real station
// in the recordings sends its CAMs with. Was 0x83 = 3200 s until 2026-09-11.
CHECK(f[basic + 2] == 0x05, "basic: lifetime 0x05 (1 s), got 0x%02x", f[basic + 2]);
CHECK(f[basic + 3] == 1, "basic: remaining hop limit 1, got %d", f[basic + 3]);
// GN Common Header
CHECK(f[common + 0] == 0x20, "common: NextHeader 2 (BTP-B), got %02x", f[common + 0]);
CHECK(f[common + 1] == 0x50, "common: HeaderType 5 (TSB) / subtype 0 (single hop), got %02x",
f[common + 1]);
CHECK(f[common + 2] == 0x02, "common: traffic class TC-ID 2 (DP2, CAM), got %02x", f[common + 2]);
CHECK(f[common + 3] == 0x80, "common: flags = mobile, got %02x", f[common + 3]);
CHECK(rd16(f + common + 4) == BTP_B + CAM_LEN,
"common: payload length must count BTP-B + payload only, got %d", rd16(f + common + 4));
CHECK(f[common + 6] == 1, "common: maximum hop limit 1, got %d", f[common + 6]);
CHECK(f[common + 7] == 0, "common: reserved, got %02x", f[common + 7]);
// SHB extended header: Source Position Vector, then 4 bytes DCC-MCO / reserved
// GN_ADDR: M flag bit 15, station type bits 14..10 (vanetza geonet/address.cpp), MID.
CHECK(rd16(f + shb) == (2u << 10), "GN_ADDR: M=0, station type 2, got %04x", rd16(f + shb));
CHECK(memcmp(f + shb + 2, k_mac, 6) == 0, "GN_ADDR MID must equal the 802.11 source address");
CHECK(rd32(f + shb + 8) == 0x89ABCDEFu, "TST, got %08lx", (unsigned long)rd32(f + shb + 8));
CHECK((int32_t)rd32(f + shb + 12) == 535546667, "latitude, got %ld",
(long)(int32_t)rd32(f + shb + 12));
CHECK((int32_t)rd32(f + shb + 16) == -10022389, "longitude, got %ld",
(long)(int32_t)rd32(f + shb + 16));
CHECK(rd16(f + shb + 20) == (0x8000 | 1234), "PAI bit 15 + speed 1234, got %04x",
rd16(f + shb + 20));
CHECK(rd16(f + shb + 22) == 2700, "heading, got %d", rd16(f + shb + 22));
CHECK(rd32(f + shb + 24) == 0, "DCC-MCO / reserved: present and zero, got %08lx",
(unsigned long)rd32(f + shb + 24));
// BTP-B, payload
CHECK(rd16(f + btp) == 2001, "BTP-B destination port, got %d", rd16(f + btp));
CHECK(rd16(f + btp + 2) == 0, "BTP-B destination port info, got %d", rd16(f + btp + 2));
CHECK(memcmp(f + pay, k_cam, (size_t)CAM_LEN) == 0, "payload bytes");
// ...and back through the RX path
const uint8_t *g = tu_guarded(f, len);
gn_rx_t rx;
const bool ok = gn_unwrap_its(g, len, &rx);
CHECK(ok, "gn_unwrap_its rejected our own frame");
if (ok) {
CHECK(rx.btp_dest_port == 2001, "RX port %d", rx.btp_dest_port);
CHECK(!rx.has_geo_area, "RX reports a geo area for an SHB frame");
CHECK(!rx.signed_unverified, "RX reports an unsecured frame as signed");
CHECK(!rx.truncated, "RX reports a whole frame as truncated");
CHECK(rx.payload == g + pay, "RX payload offset %d, expected %d", (int)(rx.payload - g), pay);
CHECK(rx.payload_len == CAM_LEN, "RX payload length %d, expected %d", rx.payload_len, CAM_LEN);
CHECK(rx.payload_len == CAM_LEN && memcmp(rx.payload, k_cam, (size_t)CAM_LEN) == 0,
"RX payload bytes differ from what was sent");
}
tu_pcap_add(f, len);
}
// The Source Position Vector's packed fields at their edges.
static void test_pv_encoding(void)
{
// Offsets inside the GeoNetworking packet (no 802.11 header): SO PV starts after Basic + Common.
const int pv = GN_BASIC + GN_COMMON;
uint8_t gn[GN_BUF_LEN];
// Speed is 15-bit signed (geonet.h), clamped rather than wrapped; PAI is bit 15.
static const struct { int16_t speed; bool pai; uint16_t expect; } speeds[] = {
{0, false, 0x0000}, {1234, true, 0x84D2}, {16383, false, 0x3FFF},
{16384, false, 0x3FFF}, {32767, false, 0x3FFF}, {-100, false, 0x7F9C},
{-16384, false, 0x4000}, {-32768, true, 0xC000},
};
for (size_t i = 0; i < sizeof speeds / sizeof speeds[0]; i++) {
tu_set_context("PV speed %d pai %d", speeds[i].speed, speeds[i].pai);
gn_lpv_t lpv = test_lpv();
lpv.speed_cms = speeds[i].speed;
lpv.pai = speeds[i].pai;
const int n = geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, gn, sizeof gn);
CHECK(n > 0 && rd16(gn + pv + 20) == speeds[i].expect, "speed %d pai %d: got %04x, expected %04x",
speeds[i].speed, speeds[i].pai, rd16(gn + pv + 20), speeds[i].expect);
}
// Heading is 0..3599 tenths of a degree, wrapped.
static const struct { uint16_t in, expect; } headings[] = {
{0, 0}, {2700, 2700}, {3599, 3599}, {3600, 0}, {3601, 1}, {65535, 735},
};
for (size_t i = 0; i < sizeof headings / sizeof headings[0]; i++) {
tu_set_context("PV heading %d", headings[i].in);
gn_lpv_t lpv = test_lpv();
lpv.heading_decideg = headings[i].in;
const int n = geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, gn, sizeof gn);
CHECK(n > 0 && rd16(gn + pv + 22) == headings[i].expect, "heading %d: got %d, expected %d",
headings[i].in, rd16(gn + pv + 22), headings[i].expect);
}
// Station type has 5 bits; anything larger must not spill into the M flag.
static const struct { uint8_t in; uint16_t expect; } types[] = {
{2, 0x0800}, {15, 0x3C00}, {0xFF, 0x7C00},
};
for (size_t i = 0; i < sizeof types / sizeof types[0]; i++) {
tu_set_context("PV station type %d", types[i].in);
gn_lpv_t lpv = test_lpv();
lpv.station_type = types[i].in;
const int n = geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, gn, sizeof gn);
CHECK(n > 0 && rd16(gn + pv) == types[i].expect, "station type %d: GN_ADDR %04x, expected %04x",
types[i].in, rd16(gn + pv), types[i].expect);
}
}
// Output buffers: an exact fit works and writes nothing past its end; one byte less is refused.
static void test_bounds(void)
{
const gn_lpv_t lpv = test_lpv();
const int gn_len = GN_BASIC + GN_COMMON + SHB_EXT + BTP_B + CAM_LEN;
tu_set_context("geonet_wrap_shb bounds");
CHECK(geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, tu_guard_buf(gn_len), (size_t)gn_len) == gn_len,
"geonet_wrap_shb: exact-size buffer must fit");
CHECK(geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, tu_guard_buf(gn_len - 1), (size_t)gn_len - 1) == -1,
"geonet_wrap_shb: one byte short must be refused");
uint8_t gn[GN_BUF_LEN];
geonet_wrap_shb(k_cam, CAM_LEN, &lpv, 2001, gn, sizeof gn);
for (int qos = 0; qos <= 1; qos++) {
tu_set_context("dot11p_build_frame bounds, qos=%d", qos);
const int frame_len = MAC_HDR + (qos ? QOS_CTRL : 0) + LLC_SNAP + gn_len;
CHECK(dot11p_build_frame(gn, gn_len, k_mac, tu_guard_buf(frame_len), (size_t)frame_len, qos) ==
frame_len,
"dot11p_build_frame qos=%d: exact-size buffer must fit", qos);
CHECK(dot11p_build_frame(gn, gn_len, k_mac, tu_guard_buf(frame_len - 1), (size_t)frame_len - 1,
qos) == -1,
"dot11p_build_frame qos=%d: one byte short must be refused", qos);
}
}
// The largest CAM the serial link can carry must survive the whole chain in main.c's buffers.
static void test_max_payload(void)
{
static uint8_t big[SERIAL_LINK_MAX_PAYLOAD];
for (int i = 0; i < SERIAL_LINK_MAX_PAYLOAD; i++) {
big[i] = (uint8_t)(i * 7 + 3);
}
for (int qos = 0; qos <= 1; qos++) {
tu_set_context("max payload %d, qos=%d", SERIAL_LINK_MAX_PAYLOAD, qos);
const gn_lpv_t lpv = test_lpv();
uint8_t f[FRAME_BUF_LEN];
const int hdr = MAC_HDR + (qos ? QOS_CTRL : 0) + LLC_SNAP + GN_BASIC + GN_COMMON + SHB_EXT + BTP_B;
const int len = build(big, SERIAL_LINK_MAX_PAYLOAD, &lpv, 2001, qos, f, sizeof f);
CHECK(len == hdr + SERIAL_LINK_MAX_PAYLOAD, "qos=%d: frame length %d, expected %d", qos, len,
hdr + SERIAL_LINK_MAX_PAYLOAD);
if (len <= 0) {
continue;
}
gn_rx_t rx;
const uint8_t *g = tu_guarded(f, len);
const bool ok = gn_unwrap_its(g, len, &rx);
CHECK(ok && !rx.truncated && rx.payload_len == SERIAL_LINK_MAX_PAYLOAD &&
memcmp(rx.payload, big, SERIAL_LINK_MAX_PAYLOAD) == 0,
"qos=%d: max-size payload did not round-trip", qos);
tu_pcap_add(f, len);
}
}
// ---- GeoBroadcast ---------------------------------------------------------------------------
// A GeoBroadcast DENM frame laid out by hand from EN 302 636-4-1 clause 9.8.5, since the firmware
// has no GBC builder and real RSUs send DENM this way. QoS Data, lifetime 0x79 (30 s) and the
// 44-byte extended header all as seen from the CiT One in the recordings.
static const uint8_t k_rsu_mac[6] = {0x02, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE};
static const uint8_t k_denm_stub[] = {0x02, 0x01, 0x00, 0x00, 0x30, 0x39, 0xDE, 0xAD, 0xBE,
0xEF, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
#define DENM_STUB_LEN ((int)sizeof k_denm_stub)
#define GBC_PAYLOAD_OFFSET (MAC_HDR + QOS_CTRL + LLC_SNAP + GN_BASIC + GN_COMMON + GBC_EXT + BTP_B)
static uint8_t *put(uint8_t *p, const void *src, int n)
{
memcpy(p, src, (size_t)n);
return p + n;
}
static uint8_t *put16(uint8_t *p, uint16_t v)
{
*p++ = (uint8_t)(v >> 8);
*p++ = (uint8_t)v;
return p;
}
static uint8_t *put32(uint8_t *p, uint32_t v)
{
p = put16(p, (uint16_t)(v >> 16));
return put16(p, (uint16_t)v);
}
static int build_gbc(uint8_t subtype, int32_t area_lat, int32_t area_lon, uint16_t dist_a, uint8_t *f)
{
uint8_t *p = f;
// 802.11 QoS Data: FC, duration, addr1..3, sequence control, QoS control
p = put16(p, 0x8800);
p = put16(p, 0);
p = put(p, k_bcast, 6);
p = put(p, k_rsu_mac, 6);
p = put(p, k_bcast, 6);
p = put16(p, 0x1000);
p = put16(p, 0);
p = put(p, k_llc_snap_gn, 8);
// Basic: version 1 / NH common, reserved, lifetime 30 s, RHL 10
const uint8_t basic[4] = {0x11, 0x00, 0x79, 10};
p = put(p, basic, 4);
// Common: NH BTP-B, HT 4 (GBC) / subtype = area shape, TC 1, flags 0 (stationary), PL, MHL, reserved
const uint8_t common[4] = {0x20, (uint8_t)(0x40 | subtype), 0x01, 0x00};
p = put(p, common, 4);
p = put16(p, (uint16_t)(BTP_B + DENM_STUB_LEN));
*p++ = 10;
*p++ = 0;
// GBC extended header: SN, reserved, SO PV (GN_ADDR with station type 15 = RSU, MID, TST, lat,
// lon, PAI/speed, heading), area centre lat/lon, DistanceA, DistanceB, angle, reserved
p = put16(p, 0x1234);
p = put16(p, 0);
p = put16(p, 15u << 10);
p = put(p, k_rsu_mac, 6);
p = put32(p, 1000);
p = put32(p, 535540100);
p = put32(p, 100220100);
p = put16(p, 0);
p = put16(p, 0);
p = put32(p, (uint32_t)area_lat);
p = put32(p, (uint32_t)area_lon);
p = put16(p, dist_a);
p = put16(p, subtype ? 40 : 0);
p = put16(p, subtype ? 900 : 0);
p = put16(p, 0);
// BTP-B: DENM
p = put16(p, 2002);
p = put16(p, 0);
p = put(p, k_denm_stub, DENM_STUB_LEN);
return (int)(p - f);
}
static void test_gbc_rx(void)
{
static const struct { uint8_t subtype; int32_t lat, lon; uint16_t dist_a; } areas[] = {
{0, 535540000, 100220000, 250}, // circle around the bench
{1, -338600000, 1512100000, 1000}, // rectangle; southern and far-eastern: signs and range
{2, 535540000, -100220000, 65535}, // ellipse; western, largest DistanceA
};
for (size_t i = 0; i < sizeof areas / sizeof areas[0]; i++) {
tu_set_context("GBC subtype %d", areas[i].subtype);
uint8_t f[256];
const int len = build_gbc(areas[i].subtype, areas[i].lat, areas[i].lon, areas[i].dist_a, f);
CHECK(len == GBC_PAYLOAD_OFFSET + DENM_STUB_LEN, "GBC frame length %d", len);
gn_rx_t rx;
const uint8_t *g = tu_guarded(f, len);
const bool ok = gn_unwrap_its(g, len, &rx);
CHECK(ok, "GBC subtype %d rejected", areas[i].subtype);
if (ok) {
CHECK(rx.btp_dest_port == 2002, "GBC port %d", rx.btp_dest_port);
CHECK(rx.has_geo_area, "GBC area missing");
CHECK(!rx.signed_unverified && !rx.truncated, "GBC flags signed=%d truncated=%d",
rx.signed_unverified, rx.truncated);
CHECK(rx.geo_area_lat_tenmicrodeg == areas[i].lat, "area lat %ld, expected %ld",
(long)rx.geo_area_lat_tenmicrodeg, (long)areas[i].lat);
CHECK(rx.geo_area_lon_tenmicrodeg == areas[i].lon, "area lon %ld, expected %ld",
(long)rx.geo_area_lon_tenmicrodeg, (long)areas[i].lon);
CHECK(rx.geo_area_distance_a_m == areas[i].dist_a, "DistanceA %d, expected %d",
rx.geo_area_distance_a_m, areas[i].dist_a);
CHECK(rx.payload == g + GBC_PAYLOAD_OFFSET && rx.payload_len == DENM_STUB_LEN &&
memcmp(rx.payload, k_denm_stub, (size_t)DENM_STUB_LEN) == 0,
"GBC payload offset %d length %d", (int)(rx.payload - g), rx.payload_len);
}
tu_pcap_add(f, len);
}
}
// ---- What gets rejected, and where the payload ends -----------------------------------------
// One-byte changes to a good CAM frame: what must be dropped, and what must still pass.
static void test_rejections(void)
{
const gn_lpv_t lpv = test_lpv();
uint8_t good[FRAME_BUF_LEN];
const int len = build(k_cam, CAM_LEN, &lpv, 2001, false, good, sizeof good);
// Offsets into that non-QoS frame: 802.11 0, LLC/SNAP 24, Basic 32, Common 36, SHB 44, BTP-B 72.
static const struct {
const char *what;
int offset;
uint8_t value;
bool accept;
uint16_t port;
} cases[] = {
{"management frame (beacon)", 0, 0x80, false, 0},
{"WDS (ToDS and FromDS)", 1, 0x03, false, 0},
{"LLC DSAP not 0xAA", 24, 0xAB, false, 0},
{"EtherType not 0x8947", 30, 0x08, false, 0},
{"Basic NextHeader 2 with no security envelope", 32, 0x12, false, 0},
{"Basic NextHeader 0 (any)", 32, 0x10, false, 0},
{"Common NextHeader 1 (BTP-A)", 36, 0x10, false, 0},
{"Beacon (HeaderType 1)", 37, 0x10, false, 0},
{"GeoUnicast (HeaderType 2)", 37, 0x20, false, 0},
{"multi-hop TSB (HeaderType 5, subtype 1)", 37, 0x51, false, 0},
{"BTP port 2003 (MAPEM, not accepted yet)", 73, 0xD3, false, 0},
{"BTP port 2018 (VAM, not accepted yet)", 73, 0xE2, false, 0},
{"BTP port 2002 (DENM)", 73, 0xD2, true, 2002},
{"BTP port 2004 (SPATEM)", 73, 0xD4, true, 2004},
};
for (size_t i = 0; i < sizeof cases / sizeof cases[0]; i++) {
tu_set_context("mutation: %s", cases[i].what);
uint8_t f[FRAME_BUF_LEN];
memcpy(f, good, (size_t)len);
f[cases[i].offset] = cases[i].value;
gn_rx_t rx;
const bool ok = gn_unwrap_its(tu_guarded(f, len), len, &rx);
CHECK(ok == cases[i].accept, "%s: %s", cases[i].what, ok ? "accepted" : "rejected");
if (ok && cases[i].accept) {
CHECK(rx.btp_dest_port == cases[i].port, "%s: port %d", cases[i].what, rx.btp_dest_port);
}
}
}
// The Common Header's payload length, not the end of the frame, decides where the message stops.
static void test_payload_length(void)
{
const gn_lpv_t lpv = test_lpv();
uint8_t good[FRAME_BUF_LEN];
const int len = build(k_cam, CAM_LEN, &lpv, 2001, false, good, sizeof good);
const int pl = MAC_HDR + LLC_SNAP + GN_BASIC + GN_COMMON_PAYLOAD_LEN_FIELD;
static const struct { const char *what; uint16_t value; bool accept; bool truncated; int payload_len; }
cases[] = {
{"one byte less than sent", BTP_B + CAM_LEN - 1, true, false, CAM_LEN - 1},
{"BTP-B header only, no payload", BTP_B, false, false, 0},
{"shorter than the BTP-B header", BTP_B - 1, false, false, 0},
{"zero", 0, false, false, 0},
{"far more than arrived", 0xFFFF, true, true, CAM_LEN},
};
for (size_t i = 0; i < sizeof cases / sizeof cases[0]; i++) {
tu_set_context("Common payload length: %s", cases[i].what);
uint8_t f[FRAME_BUF_LEN];
memcpy(f, good, (size_t)len);
f[pl] = (uint8_t)(cases[i].value >> 8);
f[pl + 1] = (uint8_t)cases[i].value;
gn_rx_t rx;
const uint8_t *g = tu_guarded(f, len);
const bool ok = gn_unwrap_its(g, len, &rx);
CHECK(ok == cases[i].accept, "%s: %s", cases[i].what, ok ? "accepted" : "rejected");
if (ok && cases[i].accept) {
CHECK(rx.truncated == cases[i].truncated && rx.payload == g + SHB_PAYLOAD_OFFSET &&
rx.payload_len == cases[i].payload_len,
"%s: truncated=%d payload_len=%d", cases[i].what, rx.truncated, rx.payload_len);
}
}
}
// The 8 bytes the chip's promiscuous RX appends to every frame must not reach the phone.
static void test_trailer(void)
{
uint8_t f[FRAME_BUF_LEN];
for (int qos = 0; qos <= 1; qos++) {
tu_set_context("RX trailer after an SHB frame, qos=%d", qos);
const gn_lpv_t lpv = test_lpv();
const int len = build(k_cam, CAM_LEN, &lpv, 2001, qos, f, sizeof f);
memcpy(f + len, k_rx_trailer, sizeof k_rx_trailer);
gn_rx_t rx;
const bool ok = gn_unwrap_its(tu_guarded(f, len + 8), len + 8, &rx);
CHECK(ok && !rx.truncated && rx.payload_len == CAM_LEN &&
memcmp(rx.payload, k_cam, (size_t)CAM_LEN) == 0,
"qos=%d: payload_len %d with the trailer, expected %d", qos, ok ? rx.payload_len : -1,
CAM_LEN);
}
tu_set_context("RX trailer after a GBC frame");
const int len = build_gbc(0, 535540000, 100220000, 250, f);
memcpy(f + len, k_rx_trailer, sizeof k_rx_trailer);
gn_rx_t rx;
const bool ok = gn_unwrap_its(tu_guarded(f, len + 8), len + 8, &rx);
CHECK(ok && !rx.truncated && rx.payload_len == DENM_STUB_LEN,
"GBC: payload_len %d with the trailer, expected %d", ok ? rx.payload_len : -1, DENM_STUB_LEN);
}
// ---- Secured (TS 103 097) -------------------------------------------------------------------
// Stand-in for what follows the inner packet in a real signed frame: headerInfo, signer and
// signature, 94 bytes with a digest signer. Its content is never read.
#define SIG_STUB_LEN 94
static int put_coer_length(int len, uint8_t *out)
{
if (len < 0x80) {
out[0] = (uint8_t)len;
return 1;
}
if (len <= 0xFF) {
out[0] = 0x81;
out[1] = (uint8_t)len;
return 2;
}
out[0] = 0x82;
out[1] = (uint8_t)(len >> 8);
out[2] = (uint8_t)len;
return 3;
}
// A secured CAM frame shaped like the recorded ones: our own SHB packet with the Basic Header's
// NextHeader set to 2 and everything after the Basic Header wrapped as `prefix` + COER length +
// inner packet, then the signature stand-in. Sets where the ITS payload starts and ends.
static int build_secured(const uint8_t *prefix, int prefix_len, const uint8_t *payload,
int payload_len, uint8_t *f, int *payload_start, int *payload_end)
{
const gn_lpv_t lpv = test_lpv();
uint8_t plain[FRAME_BUF_LEN];
const int plain_len = build(payload, payload_len, &lpv, 2001, false, plain, sizeof plain);
const int basic = MAC_HDR + LLC_SNAP;
const int inner = basic + GN_BASIC; // the Common Header onward
const int inner_len = plain_len - inner;
int n = inner;
memcpy(f, plain, (size_t)inner);
f[basic] = (uint8_t)((f[basic] & 0xF0) | 2); // Basic Header NextHeader: secured
memcpy(f + n, prefix, (size_t)prefix_len);
n += prefix_len;
n += put_coer_length(inner_len, f + n);
memcpy(f + n, plain + inner, (size_t)inner_len);
*payload_start = n + GN_COMMON + SHB_EXT + BTP_B;
n += inner_len;
*payload_end = n;
for (int i = 0; i < SIG_STUB_LEN; i++) {
f[n++] = (uint8_t)(0xA5 ^ i);
}
return n;
}
static const uint8_t k_signed_prefix[] = {0x03, 0x81, 0x00, 0x40, 0x03, 0x80};
static const uint8_t k_unsecured_prefix[] = {0x03, 0x80};
static void test_secured(void)
{
static uint8_t big[300];
for (int i = 0; i < (int)sizeof big; i++) {
big[i] = (uint8_t)(i * 13 + 1);
}
static const struct { const char *what; bool is_signed; int payload_len; } cases[] = {
{"signed, short length form", true, CAM_LEN}, // inner packet 83 bytes
{"signed, 1-byte long length form", true, 100}, // 140
{"signed, 2-byte long length form", true, 300}, // 340
{"top-level unsecuredData", false, CAM_LEN},
};
for (size_t c = 0; c < sizeof cases / sizeof cases[0]; c++) {
tu_set_context("secured: %s", cases[c].what);
const uint8_t *payload = cases[c].payload_len == CAM_LEN ? k_cam : big;
uint8_t f[FRAME_BUF_LEN];
int start, end;
const int len = cases[c].is_signed
? build_secured(k_signed_prefix, (int)sizeof k_signed_prefix, payload,
cases[c].payload_len, f, &start, &end)
: build_secured(k_unsecured_prefix, (int)sizeof k_unsecured_prefix, payload,
cases[c].payload_len, f, &start, &end);
gn_rx_t rx;
const uint8_t *g = tu_guarded(f, len);
const bool ok = gn_unwrap_its(g, len, &rx);
CHECK(ok, "%s: rejected", cases[c].what);
if (ok) {
CHECK(rx.signed_unverified == cases[c].is_signed, "%s: signed_unverified %d",
cases[c].what, rx.signed_unverified);
CHECK(!rx.truncated && rx.btp_dest_port == 2001, "%s: truncated %d port %d",
cases[c].what, rx.truncated, rx.btp_dest_port);
CHECK(rx.payload == g + start && rx.payload_len == cases[c].payload_len &&
memcmp(rx.payload, payload, (size_t)cases[c].payload_len) == 0,
"%s: payload offset %d length %d, expected %d / %d", cases[c].what,
(int)(rx.payload - g), rx.payload_len, start, cases[c].payload_len);
}
tu_pcap_add(f, len);
sweep(cases[c].what, f, len, start, end);
}
// One-byte changes to the signed, short-form frame. `env` is where the envelope starts.
uint8_t good[FRAME_BUF_LEN];
int start, end;
const int len = build_secured(k_signed_prefix, (int)sizeof k_signed_prefix, k_cam, CAM_LEN,
good, &start, &end);
const int env = MAC_HDR + LLC_SNAP + GN_BASIC;
const int inner = env + (int)sizeof k_signed_prefix + 1; // + one length byte
static const struct { const char *what; int offset; uint8_t value; } bad[] = {
{"legacy envelope, protocolVersion 2", 0, 0x02},
{"encryptedData", 1, 0x82},
{"hashId not a one-byte value", 2, 0x80},
{"no data, only extDataHash (preamble 0x20)", 3, 0x20},
{"inner protocolVersion 2", 4, 0x02},
{"nested signedData", 5, 0x81},
{"length form with no length bytes (0x80)", 6, 0x80},
{"length form with 3 length bytes (0x83)", 6, 0x83},
{"envelope too short for the Common Header", 6, 0x05},
};
for (size_t i = 0; i < sizeof bad / sizeof bad[0]; i++) {
tu_set_context("secured mutation: %s", bad[i].what);
uint8_t f[FRAME_BUF_LEN];
memcpy(f, good, (size_t)len);
f[env + bad[i].offset] = bad[i].value;
gn_rx_t rx;
CHECK(!gn_unwrap_its(tu_guarded(f, len), len, &rx), "%s: accepted", bad[i].what);
}
tu_set_context("secured mutation: inner packet claims more than its envelope holds");
uint8_t f[FRAME_BUF_LEN];
memcpy(f, good, (size_t)len);
f[inner + GN_COMMON_PAYLOAD_LEN_FIELD + 1]++; // Common Header payload length, low byte
gn_rx_t rx;
CHECK(!gn_unwrap_its(tu_guarded(f, len), len, &rx), "payload overrunning its envelope: accepted");
}
static void test_truncation(void)
{
const gn_lpv_t lpv = test_lpv();
uint8_t f[FRAME_BUF_LEN];
for (int qos = 0; qos <= 1; qos++) {
const int len = build(k_cam, CAM_LEN, &lpv, 2001, qos, f, sizeof f);
const int start = MAC_HDR + (qos ? QOS_CTRL : 0) + LLC_SNAP + GN_BASIC + GN_COMMON + SHB_EXT + BTP_B;
sweep(qos ? "SHB QoS" : "SHB", f, len, start, len);
}
const int len = build_gbc(0, 535540000, 100220000, 250, f);
sweep("GBC", f, len, GBC_PAYLOAD_OFFSET, len);
}
int main(int argc, char **argv)
{
tu_install_crash_handler();
tu_guard_init();
if (argc > 1 && !tu_pcap_open(argv[1])) {
fprintf(stderr, "cannot write %s\n", argv[1]);
return 2;
}
test_shb_layout(false);
test_shb_layout(true);
test_pv_encoding();
test_bounds();
test_max_payload();
test_gbc_rx();
test_rejections();
test_payload_length();
test_trailer();
test_secured();
test_truncation();
tu_pcap_close();
printf("test_chain: %d checks, %d failed\n", s_checks, s_failures);
return s_failures ? 1 : 0;
}
obu-firmware/test/host/test_replay.c
+99
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@@ -0,0 +1,99 @@
// Replays recorded air traffic through gn_unwrap_its, one pcap record at a time and exactly as the
// promiscuous RX callback hands each frame over (the recordings come through the same API), and
// writes what came out to a TSV that check_replay.py verifies independently. See README.md.
//
// Usage: test_replay out.tsv capture.pcap [capture.pcap ...]
//
// One row per pcap record:
// file, record, accepted, port, signed, truncated, area, area_lat, area_lon, area_dist, payload
// with everything after `accepted` empty for rejected frames and the payload in hex. Each frame
// is placed against the guard page, and an accepted payload that is not inside its frame is a
// failure here already.
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "gn_unwrap.h"
#include "test_util.h"
// main.c's RX_FRAME_MAX_LEN: the promiscuous callback copies at most this many bytes of a frame,
// so it is the most gn_unwrap_its ever sees on the board. Keep in step with main.c.
#define RX_FRAME_MAX_LEN 800
typedef struct {
FILE *out;
const char *path;
long records, capped, accepted, cam, denm, spatem, signed_frames, truncated, bad;
} replay_t;
static void on_frame(const uint8_t *frame, int len, int index, void *ctx)
{
replay_t *r = ctx;
r->records++;
if (len > RX_FRAME_MAX_LEN) {
len = RX_FRAME_MAX_LEN;
r->capped++;
}
tu_set_context("replay %s record %d (%d bytes)", r->path, index, len);
const uint8_t *g = tu_guarded(frame, len);
gn_rx_t rx;
const bool ok = gn_unwrap_its(g, len, &rx);
fprintf(r->out, "%s\t%d\t%d", r->path, index, ok);
if (ok) {
const uintptr_t lo = (uintptr_t)g;
const uintptr_t p = (uintptr_t)rx.payload;
if (p < lo || rx.payload_len <= 0 || p + (uintptr_t)rx.payload_len > lo + (uintptr_t)len) {
fprintf(stderr, "FAIL %s: payload outside the frame\n", tu_context());
r->bad++;
} else {
fprintf(r->out, "\t%u\t%d\t%d\t%d\t%ld\t%ld\t%u\t", rx.btp_dest_port, rx.signed_unverified,
rx.truncated, rx.has_geo_area, (long)rx.geo_area_lat_tenmicrodeg,
(long)rx.geo_area_lon_tenmicrodeg, rx.geo_area_distance_a_m);
for (int i = 0; i < rx.payload_len; i++) {
fprintf(r->out, "%02x", rx.payload[i]);
}
}
r->accepted++;
r->cam += rx.btp_dest_port == 2001;
r->denm += rx.btp_dest_port == 2002;
r->spatem += rx.btp_dest_port == 2004;
r->signed_frames += rx.signed_unverified;
r->truncated += rx.truncated;
}
fputc('\n', r->out);
}
int main(int argc, char **argv)
{
if (argc < 3) {
fprintf(stderr, "usage: test_replay out.tsv capture.pcap [capture.pcap ...]\n");
return 2;
}
tu_install_crash_handler();
tu_guard_init();
replay_t r = {0};
r.out = fopen(argv[1], "w");
if (!r.out) {
fprintf(stderr, "cannot write %s\n", argv[1]);
return 2;
}
fprintf(r.out, "file\trecord\taccepted\tport\tsigned\ttruncated\tarea\tarea_lat\tarea_lon\tarea_dist\tpayload\n");
int unreadable = 0;
for (int i = 2; i < argc; i++) {
r.path = argv[i];
if (tu_pcap_foreach(argv[i], on_frame, &r) < 0) {
fprintf(stderr, "cannot read %s as a pcap\n", argv[i]);
unreadable++;
}
}
fclose(r.out);
printf("test_replay: %ld records (%ld cut to %d bytes as main.c does), %ld accepted (CAM %ld, "
"DENM %ld, SPATEM %ld; %ld signed, %ld truncated), %ld bad\n",
r.records, r.capped, RX_FRAME_MAX_LEN, r.accepted, r.cam, r.denm, r.spatem,
r.signed_frames, r.truncated, r.bad);
return (r.bad || unreadable) ? 1 : 0;
}
obu-firmware/test/host/test_util.c
+249
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@@ -0,0 +1,249 @@
#ifndef _WIN32
#define _DEFAULT_SOURCE // MAP_ANONYMOUS under -std=c11
#endif
#include "test_util.h"
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <signal.h>
#include <sys/mman.h>
#include <unistd.h>
#endif
// ---- Crash reporting ------------------------------------------------------------------------
static char s_context[200] = "startup";
static const uint8_t *s_crash_bytes;
static const int *s_crash_len;
void tu_set_context(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsnprintf(s_context, sizeof s_context, fmt, ap);
va_end(ap);
}
const char *tu_context(void)
{
return s_context;
}
void tu_set_crash_input(const uint8_t *bytes, const int *len)
{
s_crash_bytes = bytes;
s_crash_len = len;
}
static void report_crash(const char *what)
{
fprintf(stderr, "CRASH (%s) during: %s\n", what, s_context);
if (s_crash_bytes && s_crash_len) {
fprintf(stderr, "input (%d bytes): ", *s_crash_len);
for (int i = 0; i < *s_crash_len; i++) {
fprintf(stderr, "%02x", s_crash_bytes[i]);
}
fputc('\n', stderr);
}
fflush(stderr);
}
#ifdef _WIN32
static LONG WINAPI on_crash(EXCEPTION_POINTERS *info)
{
char what[40];
snprintf(what, sizeof what, "exception 0x%08lx",
(unsigned long)info->ExceptionRecord->ExceptionCode);
report_crash(what);
return EXCEPTION_EXECUTE_HANDLER; // terminate, with the exception code as the exit status
}
void tu_install_crash_handler(void)
{
SetUnhandledExceptionFilter(on_crash);
}
#else
static void on_crash(int sig)
{
char what[40];
snprintf(what, sizeof what, "signal %d", sig);
report_crash(what); // not async-signal-safe, but the process is ending anyway
_exit(2);
}
void tu_install_crash_handler(void)
{
signal(SIGSEGV, on_crash);
signal(SIGBUS, on_crash);
signal(SIGILL, on_crash); // -fsanitize-undefined-trap-on-error traps with an illegal instruction
}
#endif
// ---- Guard page -----------------------------------------------------------------------------
static uint8_t *s_guard_end; // first byte of the no-access page
static size_t s_page_size;
void tu_guard_init(void)
{
#ifdef _WIN32
SYSTEM_INFO si;
GetSystemInfo(&si);
s_page_size = si.dwPageSize;
uint8_t *base = VirtualAlloc(NULL, 2 * s_page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
DWORD old;
if (!base || !VirtualProtect(base + s_page_size, s_page_size, PAGE_NOACCESS, &old)) {
fprintf(stderr, "guard page setup failed\n");
exit(2);
}
#else
s_page_size = (size_t)sysconf(_SC_PAGESIZE);
uint8_t *base = mmap(NULL, 2 * s_page_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (base == MAP_FAILED || mprotect(base + s_page_size, s_page_size, PROT_NONE) != 0) {
fprintf(stderr, "guard page setup failed\n");
exit(2);
}
#endif
s_guard_end = base + s_page_size;
}
uint8_t *tu_guard_buf(int len)
{
if (len < 0 || (size_t)len > s_page_size) {
fprintf(stderr, "tu_guard_buf(%d) exceeds one page\n", len);
exit(2);
}
return s_guard_end - len;
}
const uint8_t *tu_guarded(const uint8_t *frame, int len)
{
uint8_t *dst = tu_guard_buf(len);
if (len > 0) {
memcpy(dst, frame, (size_t)len);
}
return dst;
}
// ---- pcap -----------------------------------------------------------------------------------
static uint32_t rd_le32(const uint8_t *p)
{
return (uint32_t)p[0] | ((uint32_t)p[1] << 8) | ((uint32_t)p[2] << 16) | ((uint32_t)p[3] << 24);
}
static uint32_t rd_be32(const uint8_t *p)
{
return ((uint32_t)p[0] << 24) | ((uint32_t)p[1] << 16) | ((uint32_t)p[2] << 8) | (uint32_t)p[3];
}
int tu_pcap_foreach(const char *path, tu_frame_fn fn, void *ctx)
{
FILE *f = fopen(path, "rb");
if (!f) {
return -1;
}
fseek(f, 0, SEEK_END);
const long size = ftell(f);
fseek(f, 0, SEEK_SET);
if (size < 24) {
fclose(f);
return size == 0 ? 0 : -1; // the recordings include empty files
}
uint8_t *d = malloc((size_t)size);
if (!d || fread(d, 1, (size_t)size, f) != (size_t)size) {
fclose(f);
free(d);
return -1;
}
fclose(f);
const uint32_t magic = rd_le32(d);
const bool swapped = magic == 0xD4C3B2A1u || magic == 0x4D3CB2A1u;
if (!swapped && magic != 0xA1B2C3D4u && magic != 0xA1B23C4Du) {
free(d);
return -1;
}
uint32_t (*u32)(const uint8_t *) = swapped ? rd_be32 : rd_le32;
const uint32_t linktype = u32(d + 20);
if (linktype != 127 && linktype != 105) {
free(d);
return -1;
}
long off = 24;
int index = 0;
while (off + 16 <= size) {
const uint32_t incl = u32(d + off + 8);
if (incl > (uint32_t)(size - off - 16)) {
break; // last record cut off
}
const uint8_t *pkt = d + off + 16;
int len = (int)incl;
off += 16 + (long)incl;
if (linktype == 127) {
const int rt_len = len >= 4 ? (pkt[2] | (pkt[3] << 8)) : len + 1; // always little-endian
if (rt_len > len) {
index++;
continue;
}
pkt += rt_len;
len -= rt_len;
}
fn(pkt, len, index++, ctx);
}
free(d);
return index;
}
static FILE *s_pcap_out;
static void put_le32(uint8_t *p, uint32_t v)
{
p[0] = (uint8_t)v;
p[1] = (uint8_t)(v >> 8);
p[2] = (uint8_t)(v >> 16);
p[3] = (uint8_t)(v >> 24);
}
bool tu_pcap_open(const char *path)
{
// Global header: magic, version 2.4, zone 0, sigfigs 0, snaplen 65535, linktype 105.
static const uint8_t hdr[24] = {
0xD4, 0xC3, 0xB2, 0xA1, 0x02, 0x00, 0x04, 0x00, 0, 0, 0, 0, 0, 0, 0, 0,
0xFF, 0xFF, 0x00, 0x00, 105, 0, 0, 0,
};
s_pcap_out = fopen(path, "wb");
return s_pcap_out && fwrite(hdr, 1, sizeof hdr, s_pcap_out) == sizeof hdr;
}
void tu_pcap_add(const uint8_t *frame, int len)
{
static uint32_t seq;
if (!s_pcap_out || len <= 0) {
return;
}
uint8_t rec[16];
put_le32(rec + 0, seq++); // timestamp seconds: just the frame's sequence number
put_le32(rec + 4, 0);
put_le32(rec + 8, (uint32_t)len);
put_le32(rec + 12, (uint32_t)len);
fwrite(rec, 1, sizeof rec, s_pcap_out);
fwrite(frame, 1, (size_t)len, s_pcap_out);
}
void tu_pcap_close(void)
{
if (s_pcap_out) {
fclose(s_pcap_out);
s_pcap_out = NULL;
}
}
obu-firmware/test/host/test_util.h
+36
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@@ -0,0 +1,36 @@
#ifndef TEST_UTIL_H
#define TEST_UTIL_H
// Shared by the host tests: crash reporting, the guard page, and pcap reading and writing.
#include <stdbool.h>
#include <stdint.h>
// What the test is doing right now, printed if it crashes. printf-style.
void tu_set_context(const char *fmt, ...);
const char *tu_context(void);
// Also print these bytes as hex if it crashes (the fuzzer's current input). NULL to clear.
void tu_set_crash_input(const uint8_t *bytes, const int *len);
void tu_install_crash_handler(void);
// One read-write page followed by one no-access page.
void tu_guard_init(void);
// A buffer of exactly `len` bytes (at most one page) whose end touches the no-access page.
uint8_t *tu_guard_buf(int len);
// Copy of `frame` whose last byte is the last readable one: reading past it crashes.
const uint8_t *tu_guarded(const uint8_t *frame, int len);
// Calls `fn` for every record of a pcap file, with its 802.11 frame. Linktype 127 (radiotap,
// what its-g5-receiver-firmware records) has the radiotap header removed; linktype 105 is passed
// as is. The frame is otherwise exactly as captured, including the 8 bytes the ESP32-C5's
// promiscuous RX appends - which is what obu-firmware's callback receives through the same API.
// `index` counts every record, including ones skipped for a malformed radiotap header. Returns
// the number of records (0 for an empty file), or -1 if the file can't be read or isn't a pcap
// of those linktypes.
typedef void (*tu_frame_fn)(const uint8_t *frame, int len, int index, void *ctx);
int tu_pcap_foreach(const char *path, tu_frame_fn fn, void *ctx);
// Writes frames to a pcap, linktype 105 (bare 802.11).
bool tu_pcap_open(const char *path);
void tu_pcap_add(const uint8_t *frame, int len);
void tu_pcap_close(void);
#endif
obu-firmware/test/pcap_gn_tally.py
+104
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#!/usr/bin/env python3
"""Tally GeoNetworking header fields per sending station across .pcap captures.
Written to check the GN lifetime byte on air (see TODO.md), and it answers the general question
"what do real stations put in this header" too: one row per source MAC, packet type, BTP port and
lifetime byte, with a frame count.
python obu-firmware/test/pcap_gn_tally.py its-g5-receiver-firmware/recordings/*.pcap
Handles linktype 127 (radiotap, what its-g5-receiver-firmware records) and 105 (bare 802.11).
Standard library only. Pseudonym MACs rotate, so one vehicle can appear as several rows. The
pcap-over-serial dump path corrupts roughly 0.3% of frames, so a stray odd row is tooling noise.
"""
import collections
import glob
import struct
import sys
LLC_SNAP_GN = b"\xaa\xaa\x03\x00\x00\x00\x89\x47"
# (HeaderType, HeaderSubtype) from the GN Common Header -> name, EN 302 636-4-1 table 9.
HEADER_TYPES = {
(1, 0): "beacon",
(4, 0): "GBC-circle",
(4, 1): "GBC-rect",
(4, 2): "GBC-ellipse",
(5, 0): "SHB",
}
# Extended header length, i.e. the distance from the end of the Common Header to BTP-B.
EXT_LEN = {"SHB": 28, "GBC-circle": 44, "GBC-rect": 44, "GBC-ellipse": 44}
def lifetime_seconds(raw):
# Multiplier in the upper 6 bits, base in the lower 2: 50 ms, 1 s, 10 s, 100 s.
return (raw >> 2) * (0.05, 1, 10, 100)[raw & 3]
def frames(path):
with open(path, "rb") as f:
data = f.read()
if len(data) < 24:
return
magic = struct.unpack("<I", data[:4])[0]
endian = "<" if magic in (0xA1B2C3D4, 0xA1B23C4D) else ">"
linktype = struct.unpack(endian + "I", data[20:24])[0]
off = 24
while off + 16 <= len(data):
incl = struct.unpack(endian + "I", data[off + 8:off + 12])[0]
pkt = data[off + 16:off + 16 + incl]
off += 16 + incl
if linktype == 127:
if len(pkt) < 4:
continue
pkt = pkt[struct.unpack("<H", pkt[2:4])[0]:]
elif linktype != 105:
continue
yield pkt
def gn_fields(f):
if len(f) < 24 or (f[0] >> 2) & 3 != 2:
return None # Data frames only
o = 24 + (2 if f[0] & 0x80 else 0) # QoS Data carries a 2-byte QoS Control field
if f[o:o + 8] != LLC_SNAP_GN or len(f) < o + 12:
return None
o += 8
src = f[10:16].hex(":")
version, next_header, lifetime = f[o] >> 4, f[o] & 0x0F, f[o + 2]
port = "-"
if next_header == 2:
kind = "secured" # Common Header is inside the security envelope
elif next_header == 1 and len(f) >= o + 12:
c = o + 4
ht = (f[c + 1] >> 4, f[c + 1] & 0x0F)
kind = HEADER_TYPES.get(ht, "type %d/%d" % ht)
ext = EXT_LEN.get(kind)
btp = c + 8 + (ext or 0)
if ext and len(f) >= btp + 2:
port = str(struct.unpack(">H", f[btp:btp + 2])[0])
else:
kind = "nh=%d" % next_header
return src, version, kind, port, lifetime
def main(argv):
# PowerShell does not expand wildcards itself, so do it here.
paths = [p for arg in argv for p in (glob.glob(arg) or [arg])]
if not paths:
sys.exit(__doc__)
tally = collections.Counter()
for path in paths:
for frame in frames(path):
fields = gn_fields(frame)
if fields:
tally[fields] += 1
print("%-17s %3s %-11s %5s %8s %8s %7s"
% ("source", "ver", "packet", "port", "lifetime", "seconds", "frames"))
for (src, ver, kind, port, lt), n in sorted(tally.items()):
print("%-17s %3d %-11s %5s %8s %8g %7d"
% (src, ver, kind, port, "0x%02x" % lt, lifetime_seconds(lt), n))
if __name__ == "__main__":
main(sys.argv[1:])