X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=genrules.py;h=cdb1bc221470348c0d8d6c84acba718d6e332c6d;hb=a7bf4085d76bb3c92ac7692956edb8594cee9db3;hp=db138a8724e7ec4169d66db37bc95cbfbe3eb63d;hpb=0a516f6c712109cbaad8324964c94197dd8c85e5;p=flowspec-xdp diff --git a/genrules.py b/genrules.py index db138a8..cdb1bc2 100755 --- a/genrules.py +++ b/genrules.py @@ -290,6 +290,8 @@ with open("rules.h", "w") as out: use_v6_frags = False rulecnt = 0 ratelimitcnt = 0 + v4persrcratelimitcnt = 0 + v6persrcratelimitcnt = 0 lastrule = None for line in sys.stdin.readlines(): @@ -360,6 +362,7 @@ with open("rules.h", "w") as out: # Now write the match handling! first_action = None + stats_action = None last_action = None for community in line.split("("): if not community.startswith("generic, "): @@ -369,39 +372,60 @@ with open("rules.h", "w") as out: if len(blocks[1].strip()) != 10: # Should be 0x12345678 continue ty = blocks[1].strip()[:6] + high_byte = int(blocks[1].strip()[8:], 16) low_bytes = int(blocks[2].strip(") \n"), 16) - if ty == "0x8006" or ty == "0x800c": + if ty == "0x8006" or ty == "0x800c" or ty == "0x8306" or ty == "0x830c": if first_action is not None: # Two ratelimit actions, just drop the old one. RFC 8955 says we can. first_action = None exp = (low_bytes & (0xff << 23)) >> 23 if low_bytes == 0: - first_action = "return XDP_DROP;" + first_action = "{stats_replace}\nreturn XDP_DROP;" elif low_bytes & (1 << 31) != 0: # Negative limit, just drop - first_action = "return XDP_DROP;" + first_action = "{stats_replace}\nreturn XDP_DROP;" elif exp == 0xff: # NaN/INF. Just treat as INF and accept first_action = None elif exp <= 127: # < 1 - first_action = "return XDP_DROP;" + first_action = "{stats_replace}\nreturn XDP_DROP;" elif exp >= 127 + 63: # The count won't even fit in 64-bits, just accept first_action = None else: mantissa = low_bytes & ((1 << 23) - 1) value = 1.0 + mantissa / (2**23) value *= 2**(exp-127) - if ty == "0x8006": + 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 += f"const uint32_t ratelimitidx = {ratelimitcnt};\n" first_action += "uint64_t allowed_since_last = 0;\n" - first_action += "struct ratelimit *rate = bpf_map_lookup_elem(&rate_map, &ratelimitidx);\n" + if ty == "0x8006" or ty == "0x800c": + spin_lock = "bpf_spin_lock(&rate->lock);" + spin_unlock = "bpf_spin_unlock(&rate->lock);" + first_action += f"const uint32_t ratelimitidx = {ratelimitcnt};\n" + 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 */" + if proto == 4: + if high_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 + else: + if high_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 += "\tbpf_spin_lock(&rate->lock);\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) @@ -411,24 +435,33 @@ with open("rules.h", "w") as out: 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" - if ty == "0x8006": + 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 += "\t\trate->sent_time = time;\n" - first_action += "\t\tbpf_spin_unlock(&rate->lock);\n" + first_action += f"\t\t{spin_unlock}\n" first_action += "\t} else {\n" - first_action += "\t\tbpf_spin_unlock(&rate->lock);\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}\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" - ratelimitcnt += 1 elif ty == "0x8007": if low_bytes & 1 == 0: last_action = "return XDP_PASS;" if low_bytes & 2 == 2: - write_rule(f"const uint32_t ruleidx = STATIC_RULE_CNT + {rulecnt};") - write_rule("INCREMENT_MATCH(ruleidx);") + stats_action = f"const uint32_t ruleidx = STATIC_RULE_CNT + {rulecnt};\n" + stats_action += "INCREMENT_MATCH(ruleidx);" elif ty == "0x8008": assert False # We do not implement the redirect action elif ty == "0x8009": @@ -439,13 +472,16 @@ with open("rules.h", "w") as out: write_rule("uint8_t orig_tos = ip->tos;") write_rule("ip->tos = (ip->tos & 3) | " + str(low_bytes << 2) + ";") write_rule("chk = (chk - orig_tos + ip->tos);") - write_rule("if (unlikely(chk < 0)) { chk += 65534; }") + write_rule("if (unlikely(chk > 0xffff)) { chk -= 65535; }") + write_rule("else if (unlikely(chk < 0)) { chk += 65535; }") write_rule("ip->check = ~BE16(chk);") else: write_rule("ip6->priority = " + str(low_bytes >> 2) + ";") 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) + 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): + write_rule(stats_action) if last_action is not None: write_rule(last_action) if proto == 6: @@ -459,6 +495,10 @@ with open("rules.h", "w") as out: out.write(f"#define RULECNT {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")