if self.action == ASTAction.EXPR:
return self.left.write(expr_param, expr_param2)
-def parse_ast(expr, parse_expr):
+def parse_ast(expr, parse_expr, comma_is_or):
expr = expr.strip()
comma_split = expr.split(",", 1)
or_split = expr.split("||", 1)
if len(comma_split) > 1 and not "||" in comma_split[0]:
- return ASTNode(ASTAction.OR, parse_ast(comma_split[0], parse_expr), parse_ast(comma_split[1], parse_expr))
+ # Confusingly, BIRD uses `,` as either || or &&, depending on the type
+ # of expression being parsed. Specifically, a `numbers-match` uses `,`
+ # as OR, whereas a `bitmask-match` uses `,` as AND.
+ if comma_is_or:
+ return ASTNode(ASTAction.OR, parse_ast(comma_split[0], parse_expr, comma_is_or), parse_ast(comma_split[1], parse_expr, comma_is_or))
+ else:
+ return ASTNode(ASTAction.AND, parse_ast(comma_split[0], parse_expr, comma_is_or), parse_ast(comma_split[1], parse_expr, comma_is_or))
if len(or_split) > 1:
assert not "," in or_split[0]
- return ASTNode(ASTAction.OR, parse_ast(or_split[0], parse_expr), parse_ast(or_split[1], parse_expr))
+ return ASTNode(ASTAction.OR, parse_ast(or_split[0], parse_expr, comma_is_or), parse_ast(or_split[1], parse_expr, comma_is_or))
and_split = expr.split("&&", 1)
if len(and_split) > 1:
- return ASTNode(ASTAction.AND, parse_ast(and_split[0], parse_expr), parse_ast(and_split[1], parse_expr))
+ return ASTNode(ASTAction.AND, parse_ast(and_split[0], parse_expr, comma_is_or), parse_ast(and_split[1], parse_expr, comma_is_or))
if expr.strip() == "true":
return ASTNode(ASTAction.TRUE, None)
return ASTNode(ASTAction.FALSE, None)
if expr.startswith("!"):
- return ASTNode(ASTAction.NOT, parse_ast(expr[1:], parse_expr))
+ return ASTNode(ASTAction.NOT, parse_ast(expr[1:], parse_expr, comma_is_or))
return parse_expr(expr)
break;"""
def fragment_to_rule(ipproto, rules):
- ast = parse_ast(rules, parse_frag_expr)
+ ast = parse_ast(rules, parse_frag_expr, False)
return "if (!( " + ast.write(ipproto) + " )) break;"
def len_to_rule(rules):
- ast = parse_ast(rules, parse_numbers_expr)
+ ast = parse_ast(rules, parse_numbers_expr, True)
return "if (!( " + ast.write("(data_end - pktdata)") + " )) break;"
def proto_to_rule(ipproto, proto):
- ast = parse_ast(proto, parse_numbers_expr)
+ ast = parse_ast(proto, parse_numbers_expr, True)
if ipproto == 4:
return "if (!( " + ast.write("ip->protocol") + " )) break;"
return "if (!( " + ast.write("ip6->nexthdr") + " )) break;"
def icmp_type_to_rule(proto, ty):
- ast = parse_ast(ty, parse_numbers_expr)
+ ast = parse_ast(ty, parse_numbers_expr, True)
if proto == 4:
return "if (icmp == NULL) break;\nif (!( " + ast.write("icmp->type") + " )) break;"
else:
return "if (icmpv6 == NULL) break;\nif (!( " + ast.write("icmpv6->icmp6_type") + " )) break;"
def icmp_code_to_rule(proto, code):
- ast = parse_ast(code, parse_numbers_expr)
+ ast = parse_ast(code, parse_numbers_expr, True)
if proto == 4:
return "if (icmp == NULL) break;\nif (!( " + ast.write("icmp->code") + " )) break;"
else:
return "if (icmpv6 == NULL) break;\nif (!( " + ast.write("icmpv6->icmp6_code") + " )) break;"
def dscp_to_rule(proto, rules):
- ast = parse_ast(rules, parse_numbers_expr)
+ ast = parse_ast(rules, parse_numbers_expr, True)
if proto == 4:
return "if (!( " + ast.write("((ip->tos & 0xfc) >> 2)") + " )) break;"
def port_to_rule(ty, rules):
if ty == "port" :
- ast = parse_ast(rules, parse_numbers_expr)
- return "if (!ports_valid) break;\nif (!( " + ast.write("sport", "dport") + " )) break;"
+ ast = parse_ast(rules, parse_numbers_expr, True)
+ return "if (sport == -1 || dport == -1) break;\nif (!( " + ast.write("sport", "dport") + " )) break;"
- ast = parse_ast(rules, parse_numbers_expr)
- return "if (!ports_valid) break;\nif (!( " + ast.write(ty) + " )) break;"
+ ast = parse_ast(rules, parse_numbers_expr, True)
+ return "if (" + ty + " == -1) break;\nif (!( " + ast.write(ty) + " )) break;"
def tcp_flags_to_rule(rules):
- ast = parse_ast(rules, parse_bit_expr)
+ ast = parse_ast(rules, parse_bit_expr, False)
return f"""if (tcp == NULL) break;
if (!( {ast.write("(ntohs(tcp->flags) & 0xfff)")} )) break;"""
def flow_label_to_rule(rules):
- ast = parse_ast(rules, parse_bit_expr)
+ ast = parse_ast(rules, parse_bit_expr, False)
return f"""if (ip6 == NULL) break;
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;"""
rules6 = ""
rules4 = ""
use_v6_frags = False
- rulecnt = 0
+ stats_rulecnt = 0
ratelimitcnt = 0
- v4persrcratelimitcnt = 0
- v6persrcratelimitcnt = 0
+ v4persrcratelimits = []
+ v5persrcratelimits = []
+ v6persrcratelimits = []
lastrule = None
for line in sys.stdin.readlines():
# Now write the match handling!
first_action = None
- stats_action = None
+ stats_action = ""
last_action = None
for community in line.split("("):
if not community.startswith("generic, "):
if len(blocks[1].strip()) != 10: # Should be 0x12345678
continue
ty = blocks[1].strip()[:6]
- high_byte = int(blocks[1].strip()[8:], 16)
+ high_byte = int(blocks[1].strip()[6:8], 16)
+ mid_byte = int(blocks[1].strip()[8:], 16)
low_bytes = int(blocks[2].strip(") \n"), 16)
if ty == "0x8006" or ty == "0x800c" or ty == "0x8306" or ty == "0x830c":
if first_action is not None:
elif exp == 0xff:
# NaN/INF. Just treat as INF and accept
first_action = None
- elif exp <= 127: # < 1
+ elif exp < 127: # < 1
first_action = "{stats_replace}\nreturn XDP_DROP;"
- elif exp >= 127 + 63: # The count won't even fit in 64-bits, just accept
+ elif exp >= 127 + 29: # We can't handle the precision required with ns this high
first_action = None
else:
mantissa = low_bytes & ((1 << 23) - 1)
value = 1.0 + mantissa / (2**23)
value *= 2**(exp-127)
- if ty == "0x8006" or ty == "0x8306":
- accessor = "rate->rate.sent_bytes"
- else:
- accessor = "rate->rate.sent_packets"
- # Note that int64_t will overflow after 292 years of uptime
- first_action = "int64_t time = bpf_ktime_get_ns();\n"
- first_action += "uint64_t allowed_since_last = 0;\n"
+
+ first_action = "int64_t time_masked = bpf_ktime_get_ns() & RATE_TIME_MASK;\n"
+ first_action += f"int64_t per_pkt_ns = (1000000000LL << RATE_BUCKET_INTEGER_BITS) / {math.floor(value)};\n"
if ty == "0x8006" or ty == "0x800c":
spin_lock = "bpf_spin_lock(&rate->lock);"
spin_unlock = "bpf_spin_unlock(&rate->lock);"
first_action += "struct ratelimit *rate = bpf_map_lookup_elem(&rate_map, &ratelimitidx);\n"
ratelimitcnt += 1
else:
- spin_lock = "/* No locking as we're per-CPU */"
- spin_unlock = "/* No locking as we're per-CPU */"
+ spin_lock = "/* No locking as we're locked in get_v*_persrc_ratelimit */"
+ spin_unlock = "bpf_spin_unlock(rate_ptr.lock);"
if proto == 4:
- if high_byte > 32:
+ if mid_byte > 32:
continue
- first_action += f"const uint32_t srcip = ip->saddr & MASK4({high_byte});\n"
- first_action += f"void *rate_map = &v4_src_rate_{v4persrcratelimitcnt};\n"
- v4persrcratelimitcnt += 1
+ first_action += f"const uint32_t srcip = ip->saddr & MASK4({mid_byte});\n"
+ first_action += f"void *rate_map = &v4_src_rate_{len(v4persrcratelimits)};\n"
+ first_action += f"struct persrc_rate4_ptr rate_ptr = get_v4_persrc_ratelimit(srcip, rate_map, {(high_byte + 1) * 4096}, time_masked);\n"
+ first_action += f"struct persrc_rate4_entry *rate = rate_ptr.rate;\n"
+ v4persrcratelimits.append((high_byte + 1) * 4096)
+ elif mid_byte <= 64:
+ first_action += f"const uint64_t srcip = BE128BEHIGH64(ip6->saddr & MASK6({mid_byte}));\n"
+ first_action += f"void *rate_map = &v5_src_rate_{len(v5persrcratelimits)};\n"
+ first_action += f"struct persrc_rate5_ptr rate_ptr = get_v5_persrc_ratelimit(srcip, rate_map, {(high_byte + 1) * 4096}, time_masked);\n"
+ first_action += f"struct persrc_rate5_entry *rate = rate_ptr.rate;\n"
+ v5persrcratelimits.append((high_byte + 1) * 4096)
else:
- if high_byte > 128:
+ if mid_byte > 128:
continue
- first_action += f"const uint128_t srcip = ip6->saddr & MASK6({high_byte});\n"
- first_action += f"void *rate_map = &v6_src_rate_{v6persrcratelimitcnt};\n"
- v6persrcratelimitcnt += 1
- first_action += f"struct percpu_ratelimit *rate = bpf_map_lookup_elem(rate_map, &srcip);\n"
- first_action += "if (rate) {\n"
- first_action += f"\t{spin_lock}\n"
- first_action += f"\tif (likely({accessor} > 0))" + " {\n"
- first_action += "\t\tint64_t diff = time - rate->sent_time;\n"
- # Unlikely or not, if the flow is slow, take a perf hit (though with the else if branch it doesn't matter)
- first_action += "\t\tif (unlikely(diff > 1000000000))\n"
- first_action += f"\t\t\t{accessor} = 0;\n"
- first_action += "\t\telse if (likely(diff > 0))\n"
- first_action += f"\t\t\tallowed_since_last = ((uint64_t)diff) * {math.floor(value)} / 1000000000;\n"
- first_action += "\t}\n"
- first_action += f"\tif ({accessor} - ((int64_t)allowed_since_last) <= 0)" + " {\n"
+ first_action += f"const uint128_t srcip = ip6->saddr & MASK6({mid_byte});\n"
+ first_action += f"void *rate_map = &v6_src_rate_{len(v6persrcratelimits)};\n"
+ first_action += f"struct persrc_rate6_ptr rate_ptr = get_v6_persrc_ratelimit(srcip, rate_map, {(high_byte + 1) * 4096}, time_masked);\n"
+ first_action += f"struct persrc_rate6_entry *rate = rate_ptr.rate;\n"
+ v6persrcratelimits.append((high_byte + 1) * 4096)
if ty == "0x8006" or ty == "0x8306":
- first_action += f"\t\t{accessor} = data_end - pktdata;\n"
+ first_action += "uint64_t amt = data_end - pktdata;\n"
else:
- first_action += f"\t\t{accessor} = 1;\n"
- first_action += "\t\trate->sent_time = time;\n"
- first_action += f"\t\t{spin_unlock}\n"
+ first_action += "uint64_t amt = 1;\n"
+ first_action += "if (rate) {\n"
+ first_action += f"\t{spin_lock}\n"
+ first_action += "\tint64_t bucket_pkts = (rate->sent_time & (~RATE_TIME_MASK)) >> (64 - RATE_BUCKET_BITS);\n"
+ # We mask the top 12 bits, so date overflows every 52 days, handled below
+ first_action += "\tint64_t time_diff = time_masked - ((int64_t)(rate->sent_time & RATE_TIME_MASK));\n"
+ first_action += "\tif (unlikely(time_diff < -1000000000 || time_diff > 16000000000)) {\n"
+ first_action += "\t\tbucket_pkts = 0;\n"
first_action += "\t} else {\n"
+ first_action += "\t\tif (unlikely(time_diff < 0)) { time_diff = 0; }\n"
+ first_action += f"\t\tint64_t pkts_since_last = (time_diff << RATE_BUCKET_BITS) * amt / per_pkt_ns;\n"
+ first_action += "\t\tbucket_pkts -= pkts_since_last;\n"
+ first_action += "\t}\n"
+ first_action += "\tif (bucket_pkts >= (((1 << RATE_BUCKET_INTEGER_BITS) - 1) << RATE_BUCKET_DECIMAL_BITS)) {\n"
first_action += f"\t\t{spin_unlock}\n"
first_action += "\t\t{stats_replace}\n"
first_action += "\t\treturn XDP_DROP;\n"
+ first_action += "\t} else {\n"
+ first_action += "\t\tif (unlikely(bucket_pkts < 0)) bucket_pkts = 0;\n"
+ first_action += f"\t\trate->sent_time = time_masked | ((bucket_pkts + (1 << RATE_BUCKET_DECIMAL_BITS)) << (64 - RATE_BUCKET_BITS));\n"
+ first_action += f"\t\t{spin_unlock}\n"
first_action += "\t}\n"
- if ty == "0x8306" or ty == "0x830c":
- first_action += "} else {\n"
- first_action += "\tstruct percpu_ratelimit new_rate = { .sent_time = time, };\n"
- first_action += "\trate = &new_rate;\n"
- if ty == "0x8006" or ty == "0x8306":
- first_action += f"\t\t{accessor} = data_end - pktdata;\n"
- else:
- first_action += f"\t\t{accessor} = 1;\n"
- first_action += "\tbpf_map_update_elem(rate_map, &srcip, rate, BPF_ANY);\n"
first_action += "}\n"
elif ty == "0x8007":
if low_bytes & 1 == 0:
last_action = "return XDP_PASS;"
if low_bytes & 2 == 2:
- stats_action = f"const uint32_t ruleidx = STATIC_RULE_CNT + {rulecnt};\n"
+ stats_action = f"const uint32_t ruleidx = STATIC_RULE_CNT + {stats_rulecnt};\n"
stats_action += "INCREMENT_MATCH(ruleidx);"
elif ty == "0x8008":
assert False # We do not implement the redirect action
write_rule("ip6->flow_lbl[0] = (ip6->flow_lbl[0] & 0x3f) | " + str((low_bytes & 3) << 6) + ";")
if first_action is not None:
write_rule(first_action.replace("{stats_replace}", stats_action))
- if stats_action is not None and (first_action is None or "{stats_replace}" not in first_action):
+ if stats_action != "" and (first_action is None or "{stats_replace}" not in first_action):
write_rule(stats_action)
if last_action is not None:
write_rule(last_action)
rules6 += "\t} while(0);\\\n"
else:
rules4 += "\t} while(0);\\\n"
- rulecnt += 1
+ if stats_action != "":
+ print(rule)
+ stats_rulecnt += 1
lastrule = None
out.write("\n")
- out.write(f"#define RULECNT {rulecnt}\n")
+ out.write(f"#define STATS_RULECNT {stats_rulecnt}\n")
if ratelimitcnt != 0:
out.write(f"#define RATE_CNT {ratelimitcnt}\n")
- if v4persrcratelimitcnt != 0:
- out.write(f"#define V4_SRC_RATE_CNT {v4persrcratelimitcnt}\n")
- if v6persrcratelimitcnt != 0:
- out.write(f"#define V6_SRC_RATE_CNT {v6persrcratelimitcnt}\n")
if rules4 != "":
out.write("#define NEED_V4_PARSE\n")
out.write("#define RULES4 {\\\n" + rules4 + "}\n")
if args.v6frag == "ignore-parse-if-rule":
if use_v6_frags:
out.write("#define PARSE_V6_FRAG PARSE\n")
+ with open("maps.h", "w") as out:
+ for idx, limit in enumerate(v4persrcratelimits):
+ out.write(f"SRC_RATE_DEFINE(4, {idx}, {limit})\n")
+ for idx, limit in enumerate(v5persrcratelimits):
+ out.write(f"SRC_RATE_DEFINE(5, {idx}, {limit})\n")
+ for idx, limit in enumerate(v6persrcratelimits):
+ out.write(f"SRC_RATE_DEFINE(6, {idx}, {limit})\n")
projects / flowspec-xdp / blobdiff