1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (c) 2017 Facebook 3 #include <stddef.h> 4 #include <stdbool.h> 5 #include <string.h> 6 #include <linux/pkt_cls.h> 7 #include <linux/bpf.h> 8 #include <linux/in.h> 9 #include <linux/if_ether.h> 10 #include <linux/ip.h> 11 #include <linux/ipv6.h> 12 #include <linux/icmp.h> 13 #include <linux/icmpv6.h> 14 #include <linux/tcp.h> 15 #include <linux/udp.h> 16 #include "bpf_helpers.h" 17 #include "test_iptunnel_common.h" 18 #include "bpf_endian.h" 19 20 int _version SEC("version") = 1; 21 22 static __u32 rol32(__u32 word, unsigned int shift) 23 { 24 return (word << shift) | (word >> ((-shift) & 31)); 25 } 26 27 /* copy paste of jhash from kernel sources to make sure llvm 28 * can compile it into valid sequence of bpf instructions 29 */ 30 #define __jhash_mix(a, b, c) \ 31 { \ 32 a -= c; a ^= rol32(c, 4); c += b; \ 33 b -= a; b ^= rol32(a, 6); a += c; \ 34 c -= b; c ^= rol32(b, 8); b += a; \ 35 a -= c; a ^= rol32(c, 16); c += b; \ 36 b -= a; b ^= rol32(a, 19); a += c; \ 37 c -= b; c ^= rol32(b, 4); b += a; \ 38 } 39 40 #define __jhash_final(a, b, c) \ 41 { \ 42 c ^= b; c -= rol32(b, 14); \ 43 a ^= c; a -= rol32(c, 11); \ 44 b ^= a; b -= rol32(a, 25); \ 45 c ^= b; c -= rol32(b, 16); \ 46 a ^= c; a -= rol32(c, 4); \ 47 b ^= a; b -= rol32(a, 14); \ 48 c ^= b; c -= rol32(b, 24); \ 49 } 50 51 #define JHASH_INITVAL 0xdeadbeef 52 53 typedef unsigned int u32; 54 55 static u32 jhash(const void *key, u32 length, u32 initval) 56 { 57 u32 a, b, c; 58 const unsigned char *k = key; 59 60 a = b = c = JHASH_INITVAL + length + initval; 61 62 while (length > 12) { 63 a += *(u32 *)(k); 64 b += *(u32 *)(k + 4); 65 c += *(u32 *)(k + 8); 66 __jhash_mix(a, b, c); 67 length -= 12; 68 k += 12; 69 } 70 switch (length) { 71 case 12: c += (u32)k[11]<<24; 72 case 11: c += (u32)k[10]<<16; 73 case 10: c += (u32)k[9]<<8; 74 case 9: c += k[8]; 75 case 8: b += (u32)k[7]<<24; 76 case 7: b += (u32)k[6]<<16; 77 case 6: b += (u32)k[5]<<8; 78 case 5: b += k[4]; 79 case 4: a += (u32)k[3]<<24; 80 case 3: a += (u32)k[2]<<16; 81 case 2: a += (u32)k[1]<<8; 82 case 1: a += k[0]; 83 __jhash_final(a, b, c); 84 case 0: /* Nothing left to add */ 85 break; 86 } 87 88 return c; 89 } 90 91 static u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval) 92 { 93 a += initval; 94 b += initval; 95 c += initval; 96 __jhash_final(a, b, c); 97 return c; 98 } 99 100 static u32 jhash_2words(u32 a, u32 b, u32 initval) 101 { 102 return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2)); 103 } 104 105 #define PCKT_FRAGMENTED 65343 106 #define IPV4_HDR_LEN_NO_OPT 20 107 #define IPV4_PLUS_ICMP_HDR 28 108 #define IPV6_PLUS_ICMP_HDR 48 109 #define RING_SIZE 2 110 #define MAX_VIPS 12 111 #define MAX_REALS 5 112 #define CTL_MAP_SIZE 16 113 #define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE) 114 #define F_IPV6 (1 << 0) 115 #define F_HASH_NO_SRC_PORT (1 << 0) 116 #define F_ICMP (1 << 0) 117 #define F_SYN_SET (1 << 1) 118 119 struct packet_description { 120 union { 121 __be32 src; 122 __be32 srcv6[4]; 123 }; 124 union { 125 __be32 dst; 126 __be32 dstv6[4]; 127 }; 128 union { 129 __u32 ports; 130 __u16 port16[2]; 131 }; 132 __u8 proto; 133 __u8 flags; 134 }; 135 136 struct ctl_value { 137 union { 138 __u64 value; 139 __u32 ifindex; 140 __u8 mac[6]; 141 }; 142 }; 143 144 struct vip_meta { 145 __u32 flags; 146 __u32 vip_num; 147 }; 148 149 struct real_definition { 150 union { 151 __be32 dst; 152 __be32 dstv6[4]; 153 }; 154 __u8 flags; 155 }; 156 157 struct vip_stats { 158 __u64 bytes; 159 __u64 pkts; 160 }; 161 162 struct eth_hdr { 163 unsigned char eth_dest[ETH_ALEN]; 164 unsigned char eth_source[ETH_ALEN]; 165 unsigned short eth_proto; 166 }; 167 168 struct { 169 __u32 type; 170 __u32 max_entries; 171 struct vip *key; 172 struct vip_meta *value; 173 } vip_map SEC(".maps") = { 174 .type = BPF_MAP_TYPE_HASH, 175 .max_entries = MAX_VIPS, 176 }; 177 178 struct { 179 __u32 type; 180 __u32 max_entries; 181 __u32 *key; 182 __u32 *value; 183 } ch_rings SEC(".maps") = { 184 .type = BPF_MAP_TYPE_ARRAY, 185 .max_entries = CH_RINGS_SIZE, 186 }; 187 188 struct { 189 __u32 type; 190 __u32 max_entries; 191 __u32 *key; 192 struct real_definition *value; 193 } reals SEC(".maps") = { 194 .type = BPF_MAP_TYPE_ARRAY, 195 .max_entries = MAX_REALS, 196 }; 197 198 struct { 199 __u32 type; 200 __u32 max_entries; 201 __u32 *key; 202 struct vip_stats *value; 203 } stats SEC(".maps") = { 204 .type = BPF_MAP_TYPE_PERCPU_ARRAY, 205 .max_entries = MAX_VIPS, 206 }; 207 208 struct { 209 __u32 type; 210 __u32 max_entries; 211 __u32 *key; 212 struct ctl_value *value; 213 } ctl_array SEC(".maps") = { 214 .type = BPF_MAP_TYPE_ARRAY, 215 .max_entries = CTL_MAP_SIZE, 216 }; 217 218 static __u32 get_packet_hash(struct packet_description *pckt, 219 bool ipv6) 220 { 221 if (ipv6) 222 return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS), 223 pckt->ports, CH_RINGS_SIZE); 224 else 225 return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE); 226 } 227 228 static bool get_packet_dst(struct real_definition **real, 229 struct packet_description *pckt, 230 struct vip_meta *vip_info, 231 bool is_ipv6) 232 { 233 __u32 hash = get_packet_hash(pckt, is_ipv6); 234 __u32 key = RING_SIZE * vip_info->vip_num + hash % RING_SIZE; 235 __u32 *real_pos; 236 237 if (hash != 0x358459b7 /* jhash of ipv4 packet */ && 238 hash != 0x2f4bc6bb /* jhash of ipv6 packet */) 239 return 0; 240 241 real_pos = bpf_map_lookup_elem(&ch_rings, &key); 242 if (!real_pos) 243 return false; 244 key = *real_pos; 245 *real = bpf_map_lookup_elem(&reals, &key); 246 if (!(*real)) 247 return false; 248 return true; 249 } 250 251 static int parse_icmpv6(void *data, void *data_end, __u64 off, 252 struct packet_description *pckt) 253 { 254 struct icmp6hdr *icmp_hdr; 255 struct ipv6hdr *ip6h; 256 257 icmp_hdr = data + off; 258 if (icmp_hdr + 1 > data_end) 259 return TC_ACT_SHOT; 260 if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG) 261 return TC_ACT_OK; 262 off += sizeof(struct icmp6hdr); 263 ip6h = data + off; 264 if (ip6h + 1 > data_end) 265 return TC_ACT_SHOT; 266 pckt->proto = ip6h->nexthdr; 267 pckt->flags |= F_ICMP; 268 memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16); 269 memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16); 270 return TC_ACT_UNSPEC; 271 } 272 273 static int parse_icmp(void *data, void *data_end, __u64 off, 274 struct packet_description *pckt) 275 { 276 struct icmphdr *icmp_hdr; 277 struct iphdr *iph; 278 279 icmp_hdr = data + off; 280 if (icmp_hdr + 1 > data_end) 281 return TC_ACT_SHOT; 282 if (icmp_hdr->type != ICMP_DEST_UNREACH || 283 icmp_hdr->code != ICMP_FRAG_NEEDED) 284 return TC_ACT_OK; 285 off += sizeof(struct icmphdr); 286 iph = data + off; 287 if (iph + 1 > data_end) 288 return TC_ACT_SHOT; 289 if (iph->ihl != 5) 290 return TC_ACT_SHOT; 291 pckt->proto = iph->protocol; 292 pckt->flags |= F_ICMP; 293 pckt->src = iph->daddr; 294 pckt->dst = iph->saddr; 295 return TC_ACT_UNSPEC; 296 } 297 298 static bool parse_udp(void *data, __u64 off, void *data_end, 299 struct packet_description *pckt) 300 { 301 struct udphdr *udp; 302 udp = data + off; 303 304 if (udp + 1 > data_end) 305 return false; 306 307 if (!(pckt->flags & F_ICMP)) { 308 pckt->port16[0] = udp->source; 309 pckt->port16[1] = udp->dest; 310 } else { 311 pckt->port16[0] = udp->dest; 312 pckt->port16[1] = udp->source; 313 } 314 return true; 315 } 316 317 static bool parse_tcp(void *data, __u64 off, void *data_end, 318 struct packet_description *pckt) 319 { 320 struct tcphdr *tcp; 321 322 tcp = data + off; 323 if (tcp + 1 > data_end) 324 return false; 325 326 if (tcp->syn) 327 pckt->flags |= F_SYN_SET; 328 329 if (!(pckt->flags & F_ICMP)) { 330 pckt->port16[0] = tcp->source; 331 pckt->port16[1] = tcp->dest; 332 } else { 333 pckt->port16[0] = tcp->dest; 334 pckt->port16[1] = tcp->source; 335 } 336 return true; 337 } 338 339 static int process_packet(void *data, __u64 off, void *data_end, 340 bool is_ipv6, struct __sk_buff *skb) 341 { 342 void *pkt_start = (void *)(long)skb->data; 343 struct packet_description pckt = {}; 344 struct eth_hdr *eth = pkt_start; 345 struct bpf_tunnel_key tkey = {}; 346 struct vip_stats *data_stats; 347 struct real_definition *dst; 348 struct vip_meta *vip_info; 349 struct ctl_value *cval; 350 __u32 v4_intf_pos = 1; 351 __u32 v6_intf_pos = 2; 352 struct ipv6hdr *ip6h; 353 struct vip vip = {}; 354 struct iphdr *iph; 355 int tun_flag = 0; 356 __u16 pkt_bytes; 357 __u64 iph_len; 358 __u32 ifindex; 359 __u8 protocol; 360 __u32 vip_num; 361 int action; 362 363 tkey.tunnel_ttl = 64; 364 if (is_ipv6) { 365 ip6h = data + off; 366 if (ip6h + 1 > data_end) 367 return TC_ACT_SHOT; 368 369 iph_len = sizeof(struct ipv6hdr); 370 protocol = ip6h->nexthdr; 371 pckt.proto = protocol; 372 pkt_bytes = bpf_ntohs(ip6h->payload_len); 373 off += iph_len; 374 if (protocol == IPPROTO_FRAGMENT) { 375 return TC_ACT_SHOT; 376 } else if (protocol == IPPROTO_ICMPV6) { 377 action = parse_icmpv6(data, data_end, off, &pckt); 378 if (action >= 0) 379 return action; 380 off += IPV6_PLUS_ICMP_HDR; 381 } else { 382 memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16); 383 memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16); 384 } 385 } else { 386 iph = data + off; 387 if (iph + 1 > data_end) 388 return TC_ACT_SHOT; 389 if (iph->ihl != 5) 390 return TC_ACT_SHOT; 391 392 protocol = iph->protocol; 393 pckt.proto = protocol; 394 pkt_bytes = bpf_ntohs(iph->tot_len); 395 off += IPV4_HDR_LEN_NO_OPT; 396 397 if (iph->frag_off & PCKT_FRAGMENTED) 398 return TC_ACT_SHOT; 399 if (protocol == IPPROTO_ICMP) { 400 action = parse_icmp(data, data_end, off, &pckt); 401 if (action >= 0) 402 return action; 403 off += IPV4_PLUS_ICMP_HDR; 404 } else { 405 pckt.src = iph->saddr; 406 pckt.dst = iph->daddr; 407 } 408 } 409 protocol = pckt.proto; 410 411 if (protocol == IPPROTO_TCP) { 412 if (!parse_tcp(data, off, data_end, &pckt)) 413 return TC_ACT_SHOT; 414 } else if (protocol == IPPROTO_UDP) { 415 if (!parse_udp(data, off, data_end, &pckt)) 416 return TC_ACT_SHOT; 417 } else { 418 return TC_ACT_SHOT; 419 } 420 421 if (is_ipv6) 422 memcpy(vip.daddr.v6, pckt.dstv6, 16); 423 else 424 vip.daddr.v4 = pckt.dst; 425 426 vip.dport = pckt.port16[1]; 427 vip.protocol = pckt.proto; 428 vip_info = bpf_map_lookup_elem(&vip_map, &vip); 429 if (!vip_info) { 430 vip.dport = 0; 431 vip_info = bpf_map_lookup_elem(&vip_map, &vip); 432 if (!vip_info) 433 return TC_ACT_SHOT; 434 pckt.port16[1] = 0; 435 } 436 437 if (vip_info->flags & F_HASH_NO_SRC_PORT) 438 pckt.port16[0] = 0; 439 440 if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6)) 441 return TC_ACT_SHOT; 442 443 if (dst->flags & F_IPV6) { 444 cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos); 445 if (!cval) 446 return TC_ACT_SHOT; 447 ifindex = cval->ifindex; 448 memcpy(tkey.remote_ipv6, dst->dstv6, 16); 449 tun_flag = BPF_F_TUNINFO_IPV6; 450 } else { 451 cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos); 452 if (!cval) 453 return TC_ACT_SHOT; 454 ifindex = cval->ifindex; 455 tkey.remote_ipv4 = dst->dst; 456 } 457 vip_num = vip_info->vip_num; 458 data_stats = bpf_map_lookup_elem(&stats, &vip_num); 459 if (!data_stats) 460 return TC_ACT_SHOT; 461 data_stats->pkts++; 462 data_stats->bytes += pkt_bytes; 463 bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag); 464 *(u32 *)eth->eth_dest = tkey.remote_ipv4; 465 return bpf_redirect(ifindex, 0); 466 } 467 468 SEC("l4lb-demo") 469 int balancer_ingress(struct __sk_buff *ctx) 470 { 471 void *data_end = (void *)(long)ctx->data_end; 472 void *data = (void *)(long)ctx->data; 473 struct eth_hdr *eth = data; 474 __u32 eth_proto; 475 __u32 nh_off; 476 477 nh_off = sizeof(struct eth_hdr); 478 if (data + nh_off > data_end) 479 return TC_ACT_SHOT; 480 eth_proto = eth->eth_proto; 481 if (eth_proto == bpf_htons(ETH_P_IP)) 482 return process_packet(data, nh_off, data_end, false, ctx); 483 else if (eth_proto == bpf_htons(ETH_P_IPV6)) 484 return process_packet(data, nh_off, data_end, true, ctx); 485 else 486 return TC_ACT_SHOT; 487 } 488 char _license[] SEC("license") = "GPL"; 489