""" Create a deployment-realistic VANET-IDS26 test split with a strict 99:1 benign-to-attack ratio. The public VANET-IDS26 release is intentionally attack-heavy for research coverage. A deployed NIDS usually sees benign safety traffic dominate the stream, so this script builds an operational test split where attacks are rare but still represented across all 26 attack families. Examples -------- Quick schema/sampler path for the public sample file: python scripts/create_realistic_vanet_ids26_test_split.py --sample Chunked path for the full master file: python scripts/create_realistic_vanet_ids26_test_split.py ^ --input research_ready/vanet_ids26_master.csv.gz ^ --output research_ready/vanet_ids26_test_99_1.csv.gz ^ --mode chunked ^ --attack-rows 2600 Note: the bundled sample has only 1,000 benign rows. A strict 99:1 split that also includes all 26 attack classes requires at least 2,574 benign rows (26 attacks * 99 benign per attack), so use the master file for the final split. """ from __future__ import annotations import argparse import gzip import json from datetime import datetime, timezone from pathlib import Path from typing import Dict, Iterable, Mapping import pandas as pd from sklearn.utils import check_random_state ROOT = Path(__file__).resolve().parents[1] DEFAULT_MASTER = ROOT / "research_ready" / "vanet_ids26_master.csv.gz" DEFAULT_SAMPLE = ROOT / "release" / "github" / "VANET-IDS26" / "samples" / "vanet_ids26_sample.csv.gz" DEFAULT_OUTPUT = ROOT / "research_ready" / "vanet_ids26_test_99_1.csv.gz" DEFAULT_MANIFEST_DIR = ROOT / "dataset" / "manifests" BINARY_LABEL = "binary_label" MULTICLASS_LABEL = "multiclass_label" BENIGN_LABEL = 0 ATTACK_LABELS = tuple(range(1, 27)) BENIGN_TO_ATTACK_RATIO = 99 ATTACK_TYPES = { 1: "constant_position", 2: "position_offset", 3: "random_position", 4: "speed_manipulation", 5: "acceleration_manipulation", 6: "heading_manipulation", 7: "lane_spoofing", 8: "impossible_kinematics", 9: "eventual_stop", 10: "false_brake_event", 11: "false_emergency_vehicle", 12: "false_hazard_event", 13: "replay", 14: "delayed_message", 15: "timestamp_shift", 16: "stale_message_replay", 17: "sybil", 18: "impersonation", 19: "pseudonym_abuse", 20: "flooding_ddos", 21: "beacon_rate_abuse", 22: "gnss_spoofing", 23: "map_location_spoofing", 24: "ghost_vehicle", 25: "false_object_injection", 26: "object_position_shift", } ATTACK_TYPE_TO_LABEL = {name: label for label, name in ATTACK_TYPES.items()} def parse_args() -> argparse.Namespace: parser = argparse.ArgumentParser( description="Build a strict 99:1 benign/attack VANET-IDS26 test split." ) parser.add_argument( "--input", type=Path, default=DEFAULT_MASTER, help=f"Input CSV/CSV.GZ path. Default: {DEFAULT_MASTER}", ) parser.add_argument( "--output", type=Path, default=DEFAULT_OUTPUT, help=f"Output CSV/CSV.GZ path. Default: {DEFAULT_OUTPUT}", ) parser.add_argument( "--sample", action="store_true", help=f"Use the small public sample file with in-memory loading: {DEFAULT_SAMPLE}", ) parser.add_argument( "--mode", choices=("chunked", "memory"), default="chunked", help="Use chunked two-pass sampling for massive files or memory mode for small files.", ) parser.add_argument( "--chunksize", type=int, default=250_000, help="Rows per chunk for chunked mode.", ) parser.add_argument( "--attack-rows", type=int, default=2_600, help=( "Exact number of attack rows to include. Benign rows are set to " "attack_rows * 99. Default: 2600, which is 100 rows per attack " "family with --attack-strategy balanced." ), ) parser.add_argument( "--use-largest-feasible", action="store_true", help=( "Ignore --attack-rows and build the largest strict 99:1 split supported " "by the input. Use carefully on the full master file." ), ) parser.add_argument( "--attack-strategy", choices=("balanced", "proportional"), default="balanced", help=( "balanced gives each attack family nearly equal support; proportional " "preserves the source attack-family distribution as closely as possible." ), ) parser.add_argument( "--random-state", type=int, default=42, help="Random seed for reproducible sampling.", ) parser.add_argument( "--count-source", choices=("auto", "manifests", "scan"), default="auto", help=( "Where to get source label counts. auto uses local manifests when present " "and falls back to scanning the input." ), ) parser.add_argument( "--manifest-dir", type=Path, default=DEFAULT_MANIFEST_DIR, help=f"Directory containing local source manifests. Default: {DEFAULT_MANIFEST_DIR}", ) return parser.parse_args() def label_counts_from_memory(df: pd.DataFrame) -> Dict[int, int]: _require_label_columns(df.columns) counts = df[MULTICLASS_LABEL].astype("int64").value_counts().sort_index() return {int(label): int(count) for label, count in counts.items()} def label_counts_from_chunks(path: Path, chunksize: int) -> Dict[int, int]: counts: Dict[int, int] = {} for chunk in pd.read_csv( path, usecols=[BINARY_LABEL, MULTICLASS_LABEL], chunksize=chunksize, low_memory=False, ): _require_label_columns(chunk.columns) chunk_counts = chunk[MULTICLASS_LABEL].astype("int64").value_counts() for label, count in chunk_counts.items(): counts[int(label)] = counts.get(int(label), 0) + int(count) return dict(sorted(counts.items())) def label_counts_from_manifests(manifest_dir: Path) -> Dict[int, int]: benign_manifest = manifest_dir / "big_benign_runs_manifest.csv" attack_manifest = manifest_dir / "overlay_manifest.csv" if not benign_manifest.exists() or not attack_manifest.exists(): missing = [ str(path) for path in (benign_manifest, attack_manifest) if not path.exists() ] raise FileNotFoundError("Missing source manifest(s): " + ", ".join(missing)) benign = pd.read_csv(benign_manifest) attacks = pd.read_csv(attack_manifest) required_benign_cols = {"records_mobility"} required_attack_cols = {"attack_type", "overlay_rows"} if not required_benign_cols.issubset(benign.columns): raise ValueError(f"{benign_manifest} is missing {required_benign_cols}") if not required_attack_cols.issubset(attacks.columns): raise ValueError(f"{attack_manifest} is missing {required_attack_cols}") counts = {BENIGN_LABEL: int(benign["records_mobility"].sum())} grouped = attacks.groupby("attack_type")["overlay_rows"].sum() for attack_type, rows in grouped.items(): if attack_type not in ATTACK_TYPE_TO_LABEL: raise ValueError(f"Unknown attack_type in manifest: {attack_type}") counts[ATTACK_TYPE_TO_LABEL[attack_type]] = int(rows) return dict(sorted(counts.items())) def get_source_counts(path: Path, chunksize: int, count_source: str, manifest_dir: Path) -> tuple[Dict[int, int], str]: if count_source in ("auto", "manifests"): try: return label_counts_from_manifests(manifest_dir), "manifests" except (FileNotFoundError, ValueError): if count_source == "manifests": raise return label_counts_from_chunks(path, chunksize), "scan" def make_attack_quotas( label_counts: Mapping[int, int], attack_rows: int | None, strategy: str, ) -> Dict[int, int]: _validate_source_counts(label_counts) benign_rows_available = label_counts.get(BENIGN_LABEL, 0) max_attack_by_benign = benign_rows_available // BENIGN_TO_ATTACK_RATIO max_attack_by_attacks = sum(label_counts[label] for label in ATTACK_LABELS) max_attack_rows = min(max_attack_by_benign, max_attack_by_attacks) if attack_rows is None: attack_rows = max_attack_rows if attack_rows < len(ATTACK_LABELS): minimum_benign = len(ATTACK_LABELS) * BENIGN_TO_ATTACK_RATIO raise ValueError( "Cannot satisfy strict 99:1 and all 26 attack classes with " f"{attack_rows} attack rows. Need at least {len(ATTACK_LABELS)} " f"attack rows and {minimum_benign} benign rows." ) if attack_rows > max_attack_rows: raise ValueError( f"Requested {attack_rows} attack rows, but this input supports at most " f"{max_attack_rows} with a strict 99:1 ratio. Available benign rows: " f"{benign_rows_available}; available attack rows: {max_attack_by_attacks}." ) if strategy == "balanced": return _balanced_attack_quotas(label_counts, attack_rows) if strategy == "proportional": return _proportional_attack_quotas(label_counts, attack_rows) raise ValueError(f"Unknown attack strategy: {strategy}") def _balanced_attack_quotas(label_counts: Mapping[int, int], attack_rows: int) -> Dict[int, int]: quotas = {label: 1 for label in ATTACK_LABELS} remaining = attack_rows - len(ATTACK_LABELS) while remaining: progressed = False for label in ATTACK_LABELS: if quotas[label] >= label_counts[label]: continue quotas[label] += 1 remaining -= 1 progressed = True if remaining == 0: break if not progressed: raise ValueError("Attack quotas exceed available rows for the 26 attack classes.") return quotas def _proportional_attack_quotas(label_counts: Mapping[int, int], attack_rows: int) -> Dict[int, int]: total_available = sum(label_counts[label] for label in ATTACK_LABELS) raw = { label: (label_counts[label] / total_available) * attack_rows for label in ATTACK_LABELS } quotas = { label: min(label_counts[label], max(1, int(raw[label]))) for label in ATTACK_LABELS } while sum(quotas.values()) > attack_rows: candidates = [label for label in ATTACK_LABELS if quotas[label] > 1] label = max(candidates, key=lambda item: (quotas[item] - raw[item], quotas[item])) quotas[label] -= 1 while sum(quotas.values()) < attack_rows: candidates = [label for label in ATTACK_LABELS if quotas[label] < label_counts[label]] if not candidates: raise ValueError("Attack quotas exceed available rows for the 26 attack classes.") label = max(candidates, key=lambda item: (raw[item] - quotas[item], label_counts[item])) quotas[label] += 1 return quotas def build_split_in_memory( input_path: Path, output_path: Path, attack_rows: int | None, attack_strategy: str, random_state: int, ) -> pd.DataFrame: df = pd.read_csv(input_path, low_memory=False) counts = label_counts_from_memory(df) attack_quotas = make_attack_quotas(counts, attack_rows, attack_strategy) benign_rows = sum(attack_quotas.values()) * BENIGN_TO_ATTACK_RATIO rng = check_random_state(random_state) sampled_frames = [ df.loc[df[MULTICLASS_LABEL].astype("int64") == BENIGN_LABEL].sample( n=benign_rows, random_state=int(rng.randint(0, 2**31 - 1)), replace=False, ) ] for label, quota in attack_quotas.items(): sampled_frames.append( df.loc[df[MULTICLASS_LABEL].astype("int64") == label].sample( n=quota, random_state=int(rng.randint(0, 2**31 - 1)), replace=False, ) ) final_df = _shuffle(pd.concat(sampled_frames, ignore_index=True), rng) write_output(final_df, output_path) print_evaluation(final_df, counts, attack_quotas, output_path) return final_df def build_split_chunked( input_path: Path, output_path: Path, chunksize: int, attack_rows: int | None, attack_strategy: str, random_state: int, count_source: str, manifest_dir: Path, ) -> None: counts, resolved_count_source = get_source_counts(input_path, chunksize, count_source, manifest_dir) attack_quotas = make_attack_quotas(counts, attack_rows, attack_strategy) benign_rows = sum(attack_quotas.values()) * BENIGN_TO_ATTACK_RATIO rng = check_random_state(random_state) reservoirs: Dict[int, pd.DataFrame] = {} final_counts = {label: 0 for label in (BENIGN_LABEL, *ATTACK_LABELS)} tmp_output_path = output_path.with_name(output_path.name + ".tmp") output_path.parent.mkdir(parents=True, exist_ok=True) if tmp_output_path.exists(): tmp_output_path.unlink() print(f"Source counts loaded from: {resolved_count_source}") print(f"Target benign rows: {benign_rows:,}") print(f"Target attack rows: {sum(attack_quotas.values()):,}") print(f"Writing temporary output: {tmp_output_path}") with _open_text_output(tmp_output_path) as out_f: wrote_header = False for chunk_number, chunk in enumerate( pd.read_csv(input_path, chunksize=chunksize, low_memory=False), start=1, ): _require_label_columns(chunk.columns) labels = chunk[MULTICLASS_LABEL].astype("int64") benign_remaining = benign_rows - final_counts[BENIGN_LABEL] if benign_remaining > 0: benign_chunk = chunk.loc[labels == BENIGN_LABEL] if len(benign_chunk) > benign_remaining: benign_chunk = benign_chunk.iloc[:benign_remaining] if not benign_chunk.empty: benign_chunk.to_csv(out_f, index=False, header=not wrote_header) wrote_header = True final_counts[BENIGN_LABEL] += len(benign_chunk) attack_labels_in_chunk = sorted( label for label in labels.unique() if int(label) in ATTACK_LABELS ) for label in attack_labels_in_chunk: label = int(label) quota = attack_quotas[label] subset = chunk.loc[labels == label].copy() if subset.empty: continue subset["_sample_key"] = rng.random_sample(len(subset)) if label in reservoirs: subset = pd.concat([reservoirs[label], subset], ignore_index=True) reservoirs[label] = subset.nsmallest(quota, "_sample_key") if chunk_number % 100 == 0: sampled_attack_rows = sum(len(frame) for frame in reservoirs.values()) print( f"chunks={chunk_number:,} benign_written={final_counts[BENIGN_LABEL]:,} " f"attack_reservoir={sampled_attack_rows:,}" ) attack_frames = [] for label, quota in attack_quotas.items(): sampled = reservoirs.get(label) if sampled is None or len(sampled) != quota: found = 0 if sampled is None else len(sampled) raise RuntimeError(f"Sampled {found} rows for label {label}; expected {quota}.") clean_sample = sampled.drop(columns="_sample_key") final_counts[label] = len(clean_sample) attack_frames.append(clean_sample) attack_df = _shuffle(pd.concat(attack_frames, ignore_index=True), rng) with _open_text_output(tmp_output_path, append=True) as out_f: attack_df.to_csv(out_f, index=False, header=False) if output_path.exists(): output_path.unlink() tmp_output_path.replace(output_path) print_evaluation_from_counts(final_counts, counts, attack_quotas, output_path) write_split_manifest( output_path=output_path, input_path=input_path, source_counts=counts, final_counts=final_counts, attack_quotas=attack_quotas, attack_strategy=attack_strategy, random_state=random_state, chunksize=chunksize, count_source=resolved_count_source, ) def write_output(df: pd.DataFrame, output_path: Path) -> None: output_path.parent.mkdir(parents=True, exist_ok=True) df.to_csv(output_path, index=False) def print_evaluation( df: pd.DataFrame, source_counts: Mapping[int, int], expected_attack_quotas: Mapping[int, int], output_path: Path, ) -> None: final_binary = df[BINARY_LABEL].astype("int64").value_counts().sort_index() final_multi = df[MULTICLASS_LABEL].astype("int64").value_counts().sort_index() benign_rows = int(final_binary.get(BENIGN_LABEL, 0)) attack_rows = int(final_binary.get(1, 0)) total_rows = len(df) benign_pct = benign_rows / total_rows * 100 attack_pct = attack_rows / total_rows * 100 print() print("WROTE REALISTIC VANET-IDS26 TEST SPLIT") print(f"Output: {output_path}") print() print("Source multiclass counts:") print(pd.Series(source_counts, name="source_rows").sort_index().to_string()) print() print("Final binary distribution:") print(f"benign rows: {benign_rows:,} ({benign_pct:.2f}%)") print(f"attack rows: {attack_rows:,} ({attack_pct:.2f}%)") print(f"total rows: {total_rows:,}") print(f"benign:attack ratio: {benign_rows}:{attack_rows} = {benign_rows / attack_rows:.0f}:1") print() print("Final attack-family distribution:") attack_distribution = pd.DataFrame( { "expected_rows": pd.Series(expected_attack_quotas), "actual_rows": final_multi.reindex(ATTACK_LABELS, fill_value=0), } ) attack_distribution["attack_pct"] = ( attack_distribution["actual_rows"] / attack_rows * 100 ).round(4) print(attack_distribution.to_string()) assert benign_rows == attack_rows * BENIGN_TO_ATTACK_RATIO assert attack_rows == sum(expected_attack_quotas.values()) assert set(final_multi.loc[final_multi.index > 0].index) == set(ATTACK_LABELS) assert all( int(final_multi.get(label, 0)) == quota for label, quota in expected_attack_quotas.items() ) print() print("Verification: PASS - strict 99% benign / 1% attack with all 26 attacks represented.") def print_evaluation_from_counts( final_counts: Mapping[int, int], source_counts: Mapping[int, int], expected_attack_quotas: Mapping[int, int], output_path: Path, ) -> None: benign_rows = int(final_counts.get(BENIGN_LABEL, 0)) attack_rows = sum(int(final_counts.get(label, 0)) for label in ATTACK_LABELS) total_rows = benign_rows + attack_rows benign_pct = benign_rows / total_rows * 100 attack_pct = attack_rows / total_rows * 100 print() print("WROTE REALISTIC VANET-IDS26 TEST SPLIT") print(f"Output: {output_path}") print() print("Source multiclass counts:") print(pd.Series(source_counts, name="source_rows").sort_index().to_string()) print() print("Final binary distribution:") print(f"benign rows: {benign_rows:,} ({benign_pct:.2f}%)") print(f"attack rows: {attack_rows:,} ({attack_pct:.2f}%)") print(f"total rows: {total_rows:,}") print(f"benign:attack ratio: {benign_rows}:{attack_rows} = {benign_rows / attack_rows:.0f}:1") print() print("Final attack-family distribution:") attack_distribution = pd.DataFrame( { "attack_type": pd.Series(ATTACK_TYPES), "expected_rows": pd.Series(expected_attack_quotas), "actual_rows": pd.Series( {label: int(final_counts.get(label, 0)) for label in ATTACK_LABELS} ), } ) attack_distribution["attack_pct"] = ( attack_distribution["actual_rows"] / attack_rows * 100 ).round(4) print(attack_distribution.to_string()) assert benign_rows == attack_rows * BENIGN_TO_ATTACK_RATIO assert attack_rows == sum(expected_attack_quotas.values()) assert set(label for label in ATTACK_LABELS if final_counts.get(label, 0) > 0) == set(ATTACK_LABELS) assert all( int(final_counts.get(label, 0)) == quota for label, quota in expected_attack_quotas.items() ) print() print("Verification: PASS - strict 99% benign / 1% attack with all 26 attacks represented.") def write_split_manifest( output_path: Path, input_path: Path, source_counts: Mapping[int, int], final_counts: Mapping[int, int], attack_quotas: Mapping[int, int], attack_strategy: str, random_state: int, chunksize: int, count_source: str, ) -> None: manifest_path = output_path.with_name(output_path.name + ".manifest.json") attack_distribution_path = output_path.with_name( output_path.name + ".attack_distribution.csv" ) benign_rows = int(final_counts[BENIGN_LABEL]) attack_rows = sum(int(final_counts[label]) for label in ATTACK_LABELS) total_rows = benign_rows + attack_rows attack_distribution = pd.DataFrame( [ { "multiclass_label": label, "attack_type": ATTACK_TYPES[label], "source_rows": int(source_counts[label]), "sampled_rows": int(final_counts[label]), "attack_pct": int(final_counts[label]) / attack_rows * 100, } for label in ATTACK_LABELS ] ) attack_distribution.to_csv(attack_distribution_path, index=False) manifest = { "dataset_name": "VANET-IDS26 realistic 99:1 operational test split", "created_at_utc": datetime.now(timezone.utc).isoformat(), "input_path": str(input_path), "output_path": str(output_path), "attack_distribution_path": str(attack_distribution_path), "output_format": "csv.gz" if output_path.name.endswith(".csv.gz") else output_path.suffix.lstrip("."), "output_file_bytes": output_path.stat().st_size if output_path.exists() else None, "count_source": count_source, "random_state": random_state, "chunksize": chunksize, "benign_to_attack_ratio": BENIGN_TO_ATTACK_RATIO, "attack_strategy": attack_strategy, "source_counts": {str(label): int(count) for label, count in source_counts.items()}, "attack_quotas": {str(label): int(count) for label, count in attack_quotas.items()}, "final_counts": {str(label): int(count) for label, count in final_counts.items()}, "final_binary_counts": { "benign": benign_rows, "attack": attack_rows, "total": total_rows, }, "final_percentages": { "benign": benign_rows / total_rows * 100, "attack": attack_rows / total_rows * 100, }, "notes": [ "This split is designed for deployed NIDS evaluation where benign traffic dominates.", "The benign portion uses the maximum strict 99:1 size and drops only surplus benign rows that do not fit the exact ratio.", "Attack rows are under-sampled with stratification across multiclass_label 1..26.", "Rows are written as benign stream followed by sampled attacks; shuffle downstream before order-sensitive evaluation.", ], } manifest_path.write_text(json.dumps(manifest, indent=2), encoding="utf-8") print(f"Manifest: {manifest_path}") print(f"Attack distribution CSV: {attack_distribution_path}") def _open_text_output(path: Path, append: bool = False): mode = "at" if append else "wt" if ".gz" in path.suffixes: return gzip.open(path, mode, newline="", encoding="utf-8", compresslevel=1) return path.open(mode, newline="", encoding="utf-8") def _shuffle(df: pd.DataFrame, rng) -> pd.DataFrame: return df.sample( frac=1.0, random_state=int(rng.randint(0, 2**31 - 1)), ).reset_index(drop=True) def _validate_source_counts(label_counts: Mapping[int, int]) -> None: missing = [label for label in (BENIGN_LABEL, *ATTACK_LABELS) if label_counts.get(label, 0) <= 0] if missing: raise ValueError( "Input does not contain all required labels. Missing/empty multiclass labels: " + ", ".join(str(label) for label in missing) ) def _require_label_columns(columns: Iterable[str]) -> None: columns = set(columns) missing = [col for col in (BINARY_LABEL, MULTICLASS_LABEL) if col not in columns] if missing: raise ValueError(f"Input is missing required label column(s): {missing}") def main() -> None: args = parse_args() input_path = DEFAULT_SAMPLE if args.sample else args.input mode = "memory" if args.sample else args.mode if not input_path.exists(): raise FileNotFoundError(f"Input file not found: {input_path}") attack_rows = None if args.use_largest_feasible else args.attack_rows if mode == "memory": build_split_in_memory( input_path=input_path, output_path=args.output, attack_rows=attack_rows, attack_strategy=args.attack_strategy, random_state=args.random_state, ) else: build_split_chunked( input_path=input_path, output_path=args.output, chunksize=args.chunksize, attack_rows=attack_rows, attack_strategy=args.attack_strategy, random_state=args.random_state, count_source=args.count_source, manifest_dir=args.manifest_dir, ) if __name__ == "__main__": main()