_ Git - flowspec-xdp/blob - genrules.py

   1 #!/usr/bin/env python3
   2
   3 import sys
   4 import ipaddress
   5 from enum import Enum
   6 import argparse
   7 import math
   8
   9
  10 IP_PROTO_ICMP = 1
  11 IP_PROTO_ICMPV6 = 58
  12 IP_PROTO_TCP = 6
  13 IP_PROTO_UDP = 17
  14
  15 class ASTAction(Enum):
  16     OR = 1
  17     AND = 2
  18     NOT = 3
  19     FALSE = 4
  20     TRUE = 5
  21     EXPR = 6
  22 class ASTNode:
  23     def __init__(self, action, left, right=None):
  24         self.action = action
  25         if action == ASTAction.FALSE or action == ASTAction.TRUE:
  26             assert left is None and right is None
  27             return
  28         self.left = left
  29         if right is None:
  30             assert action == ASTAction.EXPR or action == ASTAction.NOT
  31         else:
  32             self.right = right
  33
  34     def write(self, expr_param, expr_param2=None):
  35         if self.action == ASTAction.OR:
  36             return "(" + self.left.write(expr_param, expr_param2) + ") || (" + self.right.write(expr_param, expr_param2) + ")"
  37         if self.action == ASTAction.AND:
  38             return "(" + self.left.write(expr_param, expr_param2) + ") && (" + self.right.write(expr_param, expr_param2) + ")"
  39         if self.action == ASTAction.NOT:
  40             return "!(" + self.left.write(expr_param, expr_param2) + ")"
  41         if self.action == ASTAction.FALSE:
  42             return "0"
  43         if self.action == ASTAction.TRUE:
  44             return "1"
  45         if self.action == ASTAction.EXPR:
  46             return self.left.write(expr_param, expr_param2)
  47
  48 def parse_ast(expr, parse_expr, comma_is_or):
  49     expr = expr.strip()
  50
  51     comma_split = expr.split(",", 1)
  52     or_split = expr.split("||", 1)
  53     if len(comma_split) > 1 and not "||" in comma_split[0]:
  54         # Confusingly, BIRD uses `,` as either || or &&, depending on the type
  55         # of expression being parsed. Specifically, a `numbers-match` uses `,`
  56         # as OR, whereas a `bitmask-match` uses `,` as AND.
  57         if comma_is_or:
  58             return ASTNode(ASTAction.OR, parse_ast(comma_split[0], parse_expr, comma_is_or), parse_ast(comma_split[1], parse_expr, comma_is_or))
  59         else:
  60             return ASTNode(ASTAction.AND, parse_ast(comma_split[0], parse_expr, comma_is_or), parse_ast(comma_split[1], parse_expr, comma_is_or))
  61     if len(or_split) > 1:
  62         assert not "," in or_split[0]
  63         return ASTNode(ASTAction.OR, parse_ast(or_split[0], parse_expr, comma_is_or), parse_ast(or_split[1], parse_expr, comma_is_or))
  64
  65     and_split = expr.split("&&", 1)
  66     if len(and_split) > 1:
  67         return ASTNode(ASTAction.AND, parse_ast(and_split[0], parse_expr, comma_is_or), parse_ast(and_split[1], parse_expr, comma_is_or))
  68
  69     if expr.strip() == "true":
  70         return ASTNode(ASTAction.TRUE, None)
  71     if expr.strip() == "false":
  72         return ASTNode(ASTAction.FALSE, None)
  73
  74     if expr.startswith("!"):
  75         return ASTNode(ASTAction.NOT, parse_ast(expr[1:], parse_expr, comma_is_or))
  76
  77     return parse_expr(expr)
  78
  79
  80 class NumbersAction(Enum):
  81     EQ = "=="
  82     GT = ">"
  83     GTOE = ">="
  84     LT = "<"
  85     LTOE = "<="
  86 class NumbersExpr:
  87     def __init__(self, action, val):
  88         self.action = action
  89         self.val = val
  90
  91     def write(self, param, param2):
  92         if param2 is not None:
  93             return "(" + param + self.action.value + self.val + ") || (" + param2 + self.action.value + self.val + ")"
  94         return param + self.action.value + self.val
  95
  96 def parse_numbers_expr(expr):
  97     space_split = expr.split(" ")
  98     if expr.startswith(">="):
  99         assert len(space_split) == 2
 100         return ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.GTOE, space_split[1]))
 101     if expr.startswith(">"):
 102         assert len(space_split) == 2
 103         return ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.GT, space_split[1]))
 104     if expr.startswith("<="):
 105         assert len(space_split) == 2
 106         return ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.LTOE, space_split[1]))
 107     if expr.startswith("<"):
 108         assert len(space_split) == 2
 109         return ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.LT, space_split[1]))
 110     if ".." in expr:
 111         rangesplit = expr.split("..")
 112         assert len(rangesplit) == 2
 113         #XXX: Are ranges really inclusive,inclusive?
 114         left = ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.GTOE, rangesplit[0]))
 115         right = ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.LTOE, rangesplit[1]))
 116         return ASTNode(ASTAction.AND, left, right)
 117
 118     if expr.startswith("= "):
 119         expr = expr[2:]
 120     return ASTNode(ASTAction.EXPR, NumbersExpr(NumbersAction.EQ, expr))
 121
 122 class FragExpr(Enum):
 123     IF = 1
 124     FF = 2
 125     DF = 3
 126     LF = 4
 127
 128     def write(self, ipproto, _param2):
 129         if ipproto == 4:
 130             if self == FragExpr.IF:
 131                 return "(ip->frag_off & BE16(IP_MF|IP_OFFSET)) != 0"
 132             elif self == FragExpr.FF:
 133                 return "((ip->frag_off & BE16(IP_MF)) != 0 && (ip->frag_off & BE16(IP_OFFSET)) == 0)"
 134             elif self == FragExpr.DF:
 135                 return "(ip->frag_off & BE16(IP_DF)) != 0"
 136             elif self == FragExpr.LF:
 137                 return "((ip->frag_off & BE16(IP_MF)) == 0 && (ip->frag_off & BE16(IP_OFFSET)) != 0)"
 138             else:
 139                 assert False
 140         else:
 141             if self == FragExpr.IF:
 142                 return "frag6 != NULL"
 143             elif self == FragExpr.FF:
 144                 return "(frag6 != NULL && (frag6->frag_off & BE16(IP6_MF)) != 0 && (frag6->frag_off & BE16(IP6_FRAGOFF)) == 0)"
 145             elif self == FragExpr.DF:
 146                 assert False # No such thing in v6
 147             elif self == FragExpr.LF:
 148                 return "(frag6 != NULL && (frag6->frag_off & BE16(IP6_MF)) == 0 && (frag6->frag_off & BE16(IP6_FRAGOFF)) != 0)"
 149             else:
 150                 assert False
 151
 152 def parse_frag_expr(expr):
 153     if expr == "is_fragment":
 154         return ASTNode(ASTAction.EXPR, FragExpr.IF)
 155     elif expr == "first_fragment":
 156         return ASTNode(ASTAction.EXPR, FragExpr.FF)
 157     elif expr == "dont_fragment":
 158         return ASTNode(ASTAction.EXPR, FragExpr.DF)
 159     elif expr == "last_fragment":
 160         return ASTNode(ASTAction.EXPR, FragExpr.LF)
 161     else:
 162         assert False
 163
 164 class BitExpr:
 165     def __init__(self, val):
 166         s = val.split("/")
 167         assert len(s) == 2
 168         self.match = s[0]
 169         self.mask = s[1]
 170
 171     def write(self, param, _param2):
 172         return f"({param} & {self.mask}) == {self.match}"
 173
 174 def parse_bit_expr(expr):
 175     return ASTNode(ASTAction.EXPR, BitExpr(expr))
 176
 177
 178 def ip_to_rule(proto, inip, ty, offset):
 179     if proto == 4:
 180         assert offset is None
 181         net = ipaddress.IPv4Network(inip.strip())
 182         if net.prefixlen == 0:
 183             return ""
 184         return f"""if ((ip->{ty} & MASK4({net.prefixlen})) != BIGEND32({int(net.network_address)}ULL))
 185         break;"""
 186     else:
 187         net = ipaddress.IPv6Network(inip.strip())
 188         if net.prefixlen == 0:
 189             return ""
 190         u32s = [(int(net.network_address) >> (3*32)) & 0xffffffff,
 191                 (int(net.network_address) >> (2*32)) & 0xffffffff,
 192                 (int(net.network_address) >> (1*32)) & 0xffffffff,
 193                 (int(net.network_address) >> (0*32)) & 0xffffffff]
 194         if offset is None:
 195             mask = f"MASK6({net.prefixlen})"
 196         else:
 197             mask = f"MASK6_OFFS({offset}, {net.prefixlen})"
 198         return f"""if ((ip6->{ty} & {mask}) != (BIGEND128({u32s[0]}ULL, {u32s[1]}ULL, {u32s[2]}ULL, {u32s[3]}ULL) & {mask}))
 199         break;"""
 200
 201 def fragment_to_rule(ipproto, rules):
 202     ast = parse_ast(rules, parse_frag_expr, False)
 203     return "if (!( " + ast.write(ipproto) + " )) break;"
 204
 205 def len_to_rule(rules):
 206     ast = parse_ast(rules, parse_numbers_expr, True)
 207     return "if (!( " + ast.write("(data_end - pktdata)") + " )) break;"
 208
 209 def proto_to_rule(ipproto, proto):
 210     ast = parse_ast(proto, parse_numbers_expr, True)
 211
 212     if ipproto == 4:
 213         return "if (!( " + ast.write("ip->protocol") + " )) break;"
 214     else:
 215         return "if (!( " + ast.write("ip6->nexthdr") + " )) break;"
 216
 217 def icmp_type_to_rule(proto, ty):
 218     ast = parse_ast(ty, parse_numbers_expr, True)
 219     if proto == 4:
 220         return "if (icmp == NULL) break;\nif (!( " + ast.write("icmp->type") + " )) break;"
 221     else:
 222         return "if (icmpv6 == NULL) break;\nif (!( " + ast.write("icmpv6->icmp6_type") + " )) break;"
 223
 224 def icmp_code_to_rule(proto, code):
 225     ast = parse_ast(code, parse_numbers_expr, True)
 226     if proto == 4:
 227         return "if (icmp == NULL) break;\nif (!( " + ast.write("icmp->code") + " )) break;"
 228     else:
 229         return "if (icmpv6 == NULL) break;\nif (!( " + ast.write("icmpv6->icmp6_code") + " )) break;"
 230
 231 def dscp_to_rule(proto, rules):
 232     ast = parse_ast(rules, parse_numbers_expr, True)
 233
 234     if proto == 4:
 235         return "if (!( " + ast.write("((ip->tos & 0xfc) >> 2)") + " )) break;"
 236     else:
 237         return "if (!( " + ast.write("((ip6->priority << 2) | ((ip6->flow_lbl[0] & 0xc0) >> 6))") + " )) break;"
 238
 239 def port_to_rule(ty, rules):
 240     if ty == "port" :
 241         ast = parse_ast(rules, parse_numbers_expr, True)
 242         return "if (sport == -1 || dport == -1) break;\nif (!( " + ast.write("sport", "dport") + " )) break;"
 243
 244     ast = parse_ast(rules, parse_numbers_expr, True)
 245     return "if (" + ty + " == -1) break;\nif (!( " + ast.write(ty) + " )) break;"
 246
 247 def tcp_flags_to_rule(rules):
 248     ast = parse_ast(rules, parse_bit_expr, False)
 249
 250     return f"""if (tcp == NULL) break;
 251 if (!( {ast.write("(ntohs(tcp->flags) & 0xfff)")} )) break;"""
 252
 253 def flow_label_to_rule(rules):
 254     ast = parse_ast(rules, parse_bit_expr, False)
 255
 256     return f"""if (ip6 == NULL) break;
 257 if (!( {ast.write("((((uint32_t)(ip6->flow_lbl[0] & 0xf)) << 2*8) | (((uint32_t)ip6->flow_lbl[1]) << 1*8) | (uint32_t)ip6->flow_lbl[0])")} )) break;"""
 258
 259
 260 with open("rules.h", "w") as out:
 261     parse = argparse.ArgumentParser()
 262     parse.add_argument("--ihl", dest="ihl", required=True, choices=["drop-options","accept-options","parse-options"])
 263     parse.add_argument("--v6frag", dest="v6frag", required=True, choices=["drop-frags","ignore","parse-frags","ignore-parse-if-rule"])
 264     parse.add_argument("--8021q", dest="vlan", required=True, choices=["drop-vlan","accept-vlan","parse-vlan"])
 265     parse.add_argument("--require-8021q", dest="vlan_tag")
 266     args = parse.parse_args(sys.argv[1:])
 267
 268     if args.ihl == "drop-options":
 269         out.write("#define PARSE_IHL XDP_DROP\n")
 270     elif args.ihl == "accept-options":
 271         out.write("#define PARSE_IHL XDP_PASS\n")
 272     elif args.ihl == "parse-options":
 273         out.write("#define PARSE_IHL PARSE\n")
 274
 275     if args.v6frag == "drop-frags":
 276         out.write("#define PARSE_V6_FRAG XDP_DROP\n")
 277     elif args.v6frag == "ignore":
 278         pass
 279     elif args.v6frag == "parse-frags":
 280         out.write("#define PARSE_V6_FRAG PARSE\n")
 281
 282     if args.vlan == "drop-vlan":
 283         out.write("#define PARSE_8021Q XDP_DROP\n")
 284     elif args.vlan == "accept-vlan":
 285         out.write("#define PARSE_8021Q XDP_PASS\n")
 286     elif args.vlan == "parse-vlan":
 287         out.write("#define PARSE_8021Q PARSE\n")
 288
 289     if args.vlan_tag is not None:
 290         if args.vlan != "parse-vlan":
 291             assert False
 292         out.write("#define REQ_8021Q " + args.vlan_tag + "\n")
 293
 294     rules6 = ""
 295     rules4 = ""
 296     use_v6_frags = False
 297     rulecnt = 0
 298     ratelimitcnt = 0
 299     v4persrcratelimits = []
 300     v6persrcratelimits = []
 301
 302     lastrule = None
 303     for line in sys.stdin.readlines():
 304         if "{" in line:
 305             if lastrule is not None:
 306                 print("Skipped rule due to lack of understood community tag: " + lastrule)
 307             lastrule = line
 308             continue
 309         if "BGP.ext_community: " in line:
 310             assert lastrule is not None
 311
 312             t = lastrule.split("{")
 313             if t[0].strip() == "flow4":
 314                 proto = 4
 315                 rules4 += "\tdo {\\\n"
 316             elif t[0].strip() == "flow6":
 317                 proto = 6
 318                 rules6 += "\tdo {\\\n"
 319             else:
 320                 continue
 321
 322             def write_rule(r):
 323                 global rules4, rules6
 324                 if proto == 6:
 325                     rules6 += "\t\t" + r.replace("\n", " \\\n\t\t") + " \\\n"
 326                 else:
 327                     rules4 += "\t\t" + r.replace("\n", " \\\n\t\t") + " \\\n"
 328
 329             rule = t[1].split("}")[0].strip()
 330             for step in rule.split(";"):
 331                 if step.strip().startswith("src") or step.strip().startswith("dst"):
 332                     nets = step.strip()[3:].strip().split(" ")
 333                     if len(nets) > 1:
 334                         assert nets[1] == "offset"
 335                         offset = nets[2]
 336                     else:
 337                         offset = None
 338                     if step.strip().startswith("src"):
 339                         write_rule(ip_to_rule(proto, nets[0], "saddr", offset))
 340                     else:
 341                         write_rule(ip_to_rule(proto, nets[0], "daddr", offset))
 342                 elif step.strip().startswith("proto") and proto == 4:
 343                     write_rule(proto_to_rule(4, step.strip()[6:]))
 344                 elif step.strip().startswith("next header") and proto == 6:
 345                     write_rule(proto_to_rule(6, step.strip()[12:]))
 346                 elif step.strip().startswith("icmp type"):
 347                     write_rule(icmp_type_to_rule(proto, step.strip()[10:]))
 348                 elif step.strip().startswith("icmp code"):
 349                     write_rule(icmp_code_to_rule(proto, step.strip()[10:]))
 350                 elif step.strip().startswith("sport") or step.strip().startswith("dport") or step.strip().startswith("port"):
 351                     write_rule(port_to_rule(step.strip().split(" ")[0], step.strip().split(" ", 1)[1]))
 352                 elif step.strip().startswith("length"):
 353                     write_rule(len_to_rule(step.strip()[7:]))
 354                 elif step.strip().startswith("dscp"):
 355                     write_rule(dscp_to_rule(proto, step.strip()[5:]))
 356                 elif step.strip().startswith("tcp flags"):
 357                     write_rule(tcp_flags_to_rule(step.strip()[10:]))
 358                 elif step.strip().startswith("label"):
 359                     write_rule(flow_label_to_rule(step.strip()[6:]))
 360                 elif step.strip().startswith("fragment"):
 361                     if proto == 6:
 362                         use_v6_frags = True
 363                     write_rule(fragment_to_rule(proto, step.strip()[9:]))
 364                 elif step.strip() == "":
 365                     pass
 366                 else:
 367                     assert False
 368
 369             # Now write the match handling!
 370             first_action = None
 371             stats_action = None
 372             last_action = None
 373             for community in line.split("("):
 374                 if not community.startswith("generic, "):
 375                     continue
 376                 blocks = community.split(",")
 377                 assert len(blocks) == 3
 378                 if len(blocks[1].strip()) != 10: # Should be 0x12345678
 379                     continue
 380                 ty = blocks[1].strip()[:6]
 381                 high_byte = int(blocks[1].strip()[6:8], 16)
 382                 mid_byte = int(blocks[1].strip()[8:], 16)
 383                 low_bytes = int(blocks[2].strip(") \n"), 16)
 384                 if ty == "0x8006" or ty == "0x800c" or ty == "0x8306" or ty == "0x830c":
 385                     if first_action is not None:
 386                         # Two ratelimit actions, just drop the old one. RFC 8955 says we can.
 387                         first_action = None
 388                     exp = (low_bytes & (0xff << 23)) >> 23
 389                     if low_bytes == 0:
 390                         first_action = "{stats_replace}\nreturn XDP_DROP;"
 391                     elif low_bytes & (1 <<  31) != 0:
 392                         # Negative limit, just drop
 393                         first_action = "{stats_replace}\nreturn XDP_DROP;"
 394                     elif exp == 0xff:
 395                         # NaN/INF. Just treat as INF and accept
 396                         first_action = None
 397                     elif exp <= 127: # < 1
 398                         first_action = "{stats_replace}\nreturn XDP_DROP;"
 399                     elif exp >= 127 + 63: # The count won't even fit in 64-bits, just accept
 400                         first_action = None
 401                     else:
 402                         mantissa = low_bytes & ((1 << 23) - 1)
 403                         value = 1.0 + mantissa / (2**23)
 404                         value *= 2**(exp-127)
 405                         if ty == "0x8006" or ty == "0x8306":
 406                             accessor = "rate->rate.sent_bytes"
 407                         else:
 408                             accessor = "rate->rate.sent_packets"
 409                         # Note that int64_t will overflow after 292 years of uptime
 410                         first_action = "int64_t time = bpf_ktime_get_ns();\n"
 411                         first_action +=  "uint64_t allowed_since_last = 0;\n"
 412                         if ty == "0x8006" or ty == "0x800c":
 413                             spin_lock = "bpf_spin_lock(&rate->lock);"
 414                             spin_unlock = "bpf_spin_unlock(&rate->lock);"
 415                             first_action += f"const uint32_t ratelimitidx = {ratelimitcnt};\n"
 416                             first_action += "struct ratelimit *rate = bpf_map_lookup_elem(&rate_map, &ratelimitidx);\n"
 417                             ratelimitcnt += 1
 418                         else:
 419                             spin_lock = "/* No locking as we're per-CPU */"
 420                             spin_unlock = "/* No locking as we're per-CPU */"
 421                             if proto == 4:
 422                                 if mid_byte > 32:
 423                                     continue
 424                                 first_action += f"const uint32_t srcip = ip->saddr & MASK4({mid_byte});\n"
 425                                 first_action += f"void *rate_map = &v4_src_rate_{len(v4persrcratelimits)};\n"
 426                                 v4persrcratelimits.append((high_byte + 1) * 1024)
 427                             else:
 428                                 if mid_byte > 128:
 429                                     continue
 430                                 first_action += f"const uint128_t srcip = ip6->saddr & MASK6({mid_byte});\n"
 431                                 first_action += f"void *rate_map = &v6_src_rate_{len(v6persrcratelimits)};\n"
 432                                 v6persrcratelimits.append((high_byte + 1) * 1024)
 433                             first_action += f"struct percpu_ratelimit *rate = bpf_map_lookup_elem(rate_map, &srcip);\n"
 434                         first_action +=  "if (rate) {\n"
 435                         first_action += f"\t{spin_lock}\n"
 436                         first_action += f"\tif (likely({accessor} > 0))" + " {\n"
 437                         first_action +=  "\t\tint64_t diff = time - rate->sent_time;\n"
 438                         # Unlikely or not, if the flow is slow, take a perf hit (though with the else if branch it doesn't matter)
 439                         first_action +=  "\t\tif (unlikely(diff > 1000000000))\n"
 440                         first_action += f"\t\t\t{accessor} = 0;\n"
 441                         first_action +=  "\t\telse if (likely(diff > 0))\n"
 442                         first_action += f"\t\t\tallowed_since_last = ((uint64_t)diff) * {math.floor(value)} / 1000000000;\n"
 443                         first_action +=  "\t}\n"
 444                         first_action += f"\tif ({accessor} - ((int64_t)allowed_since_last) <= 0)" + " {\n"
 445                         if ty == "0x8006" or ty == "0x8306":
 446                             first_action += f"\t\t{accessor} = data_end - pktdata;\n"
 447                         else:
 448                             first_action += f"\t\t{accessor} = 1;\n"
 449                         first_action +=  "\t\trate->sent_time = time;\n"
 450                         first_action += f"\t\t{spin_unlock}\n"
 451                         first_action +=  "\t} else {\n"
 452                         first_action += f"\t\t{spin_unlock}\n"
 453                         first_action +=  "\t\t{stats_replace}\n"
 454                         first_action +=  "\t\treturn XDP_DROP;\n"
 455                         first_action +=  "\t}\n"
 456                         if ty == "0x8306" or ty == "0x830c":
 457                             first_action +=  "} else {\n"
 458                             first_action +=  "\tstruct percpu_ratelimit new_rate = { .sent_time = time, };\n"
 459                             first_action +=  "\trate = &new_rate;\n"
 460                             if ty == "0x8006" or ty == "0x8306":
 461                                 first_action += f"\t\t{accessor} = data_end - pktdata;\n"
 462                             else:
 463                                 first_action += f"\t\t{accessor} = 1;\n"
 464                             first_action +=  "\tbpf_map_update_elem(rate_map, &srcip, rate, BPF_ANY);\n"
 465                         first_action +=  "}\n"
 466                 elif ty == "0x8007":
 467                     if low_bytes & 1 == 0:
 468                         last_action = "return XDP_PASS;"
 469                     if low_bytes & 2 == 2:
 470                         stats_action = f"const uint32_t ruleidx = STATIC_RULE_CNT + {rulecnt};\n"
 471                         stats_action += "INCREMENT_MATCH(ruleidx);"
 472                 elif ty == "0x8008":
 473                     assert False # We do not implement the redirect action
 474                 elif ty == "0x8009":
 475                     if low_bytes & ~0b111111 != 0:
 476                         assert False # Invalid DSCP value
 477                     if proto == 4:
 478                         write_rule("int32_t chk = ~BE16(ip->check) & 0xffff;")
 479                         write_rule("uint8_t orig_tos = ip->tos;")
 480                         write_rule("ip->tos = (ip->tos & 3) | " + str(low_bytes << 2) + ";")
 481                         write_rule("chk = (chk - orig_tos + ip->tos);")
 482                         write_rule("if (unlikely(chk > 0xffff)) { chk -= 65535; }")
 483                         write_rule("else if (unlikely(chk < 0)) { chk += 65535; }")
 484                         write_rule("ip->check = ~BE16(chk);")
 485                     else:
 486                         write_rule("ip6->priority = " + str(low_bytes >> 2) + ";")
 487                         write_rule("ip6->flow_lbl[0] = (ip6->flow_lbl[0] & 0x3f) | " + str((low_bytes & 3) << 6) + ";")
 488             if first_action is not None:
 489                 write_rule(first_action.replace("{stats_replace}", stats_action))
 490             if stats_action is not None and (first_action is None or "{stats_replace}" not in first_action):
 491                 write_rule(stats_action)
 492             if last_action is not None:
 493                 write_rule(last_action)
 494             if proto == 6:
 495                 rules6 += "\t} while(0);\\\n"
 496             else:
 497                 rules4 += "\t} while(0);\\\n"
 498             rulecnt += 1
 499             lastrule = None
 500
 501     out.write("\n")
 502     out.write(f"#define RULECNT {rulecnt}\n")
 503     if ratelimitcnt != 0:
 504         out.write(f"#define RATE_CNT {ratelimitcnt}\n")
 505     if rules4 != "":
 506         out.write("#define NEED_V4_PARSE\n")
 507         out.write("#define RULES4 {\\\n" + rules4 + "}\n")
 508     if rules6:
 509         out.write("#define NEED_V6_PARSE\n")
 510         out.write("#define RULES6 {\\\n" + rules6 + "}\n")
 511     if args.v6frag == "ignore-parse-if-rule":
 512         if use_v6_frags:
 513             out.write("#define PARSE_V6_FRAG PARSE\n")
 514     with open("maps.h", "w") as out:
 515         for idx, limit in enumerate(v4persrcratelimits):
 516             out.write(f"V4_SRC_RATE_DEFINE({idx}, {limit})\n")
 517         for idx, limit in enumerate(v6persrcratelimits):
 518             out.write(f"V6_SRC_RATE_DEFINE({idx}, {limit})\n")