X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=genrules.py;h=3f901e1c908a1595e35264279016e01e37874c7c;hb=dc5a8c8f1d9227f4741a57dee92e326302ec062d;hp=8e58e9ac6de0259bcbdc3f67636a10882d8b0deb;hpb=c9cc1ccad026928d22628ab8f5f82b3520b85a61;p=flowspec-xdp diff --git a/genrules.py b/genrules.py index 8e58e9a..3f901e1 100755 --- a/genrules.py +++ b/genrules.py @@ -199,7 +199,7 @@ def ip_to_rule(proto, inip, ty, offset): break;""" def fragment_to_rule(ipproto, rules): - ast = parse_ast(rules, parse_frag_expr, True) + ast = parse_ast(rules, parse_frag_expr, False) return "if (!( " + ast.write(ipproto) + " )) break;" def len_to_rule(rules): @@ -239,10 +239,10 @@ def dscp_to_rule(proto, rules): def port_to_rule(ty, rules): if ty == "port" : ast = parse_ast(rules, parse_numbers_expr, True) - return "if (!ports_valid) break;\nif (!( " + ast.write("sport", "dport") + " )) break;" + return "if (sport == -1 || dport == -1) break;\nif (!( " + ast.write("sport", "dport") + " )) break;" ast = parse_ast(rules, parse_numbers_expr, True) - return "if (!ports_valid) break;\nif (!( " + ast.write(ty) + " )) break;" + return "if (" + ty + " == -1) break;\nif (!( " + ast.write(ty) + " )) break;" def tcp_flags_to_rule(rules): ast = parse_ast(rules, parse_bit_expr, False) @@ -297,6 +297,7 @@ with open("rules.h", "w") as out: rulecnt = 0 ratelimitcnt = 0 v4persrcratelimits = [] + v5persrcratelimits = [] v6persrcratelimits = [] lastrule = None @@ -394,21 +395,17 @@ with open("rules.h", "w") as out: 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);" @@ -416,52 +413,55 @@ with open("rules.h", "w") as out: 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 mid_byte > 32: continue 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" - v4persrcratelimits.append((high_byte + 1) * 1024) + 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 mid_byte > 128: continue 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" - v6persrcratelimits.append((high_byte + 1) * 1024) - 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"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: @@ -513,6 +513,8 @@ with open("rules.h", "w") as out: out.write("#define PARSE_V6_FRAG PARSE\n") with open("maps.h", "w") as out: for idx, limit in enumerate(v4persrcratelimits): - out.write(f"V4_SRC_RATE_DEFINE({idx}, {limit})\n") + 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"V6_SRC_RATE_DEFINE({idx}, {limit})\n") + out.write(f"SRC_RATE_DEFINE(6, {idx}, {limit})\n")