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 __uint(type, BPF_MAP_TYPE_HASH); 170 __uint(max_entries, MAX_VIPS); 171 __type(key, struct vip); 172 __type(value, struct vip_meta); 173 } vip_map SEC(".maps"); 174 175 struct { 176 __uint(type, BPF_MAP_TYPE_ARRAY); 177 __uint(max_entries, CH_RINGS_SIZE); 178 __type(key, __u32); 179 __type(value, __u32); 180 } ch_rings SEC(".maps"); 181 182 struct { 183 __uint(type, BPF_MAP_TYPE_ARRAY); 184 __uint(max_entries, MAX_REALS); 185 __type(key, __u32); 186 __type(value, struct real_definition); 187 } reals SEC(".maps"); 188 189 struct { 190 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); 191 __uint(max_entries, MAX_VIPS); 192 __type(key, __u32); 193 __type(value, struct vip_stats); 194 } stats SEC(".maps"); 195 196 struct { 197 __uint(type, BPF_MAP_TYPE_ARRAY); 198 __uint(max_entries, CTL_MAP_SIZE); 199 __type(key, __u32); 200 __type(value, struct ctl_value); 201 } ctl_array SEC(".maps"); 202 203 static __u32 get_packet_hash(struct packet_description *pckt, 204 bool ipv6) 205 { 206 if (ipv6) 207 return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS), 208 pckt->ports, CH_RINGS_SIZE); 209 else 210 return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE); 211 } 212 213 static bool get_packet_dst(struct real_definition **real, 214 struct packet_description *pckt, 215 struct vip_meta *vip_info, 216 bool is_ipv6) 217 { 218 __u32 hash = get_packet_hash(pckt, is_ipv6); 219 __u32 key = RING_SIZE * vip_info->vip_num + hash % RING_SIZE; 220 __u32 *real_pos; 221 222 if (hash != 0x358459b7 /* jhash of ipv4 packet */ && 223 hash != 0x2f4bc6bb /* jhash of ipv6 packet */) 224 return 0; 225 226 real_pos = bpf_map_lookup_elem(&ch_rings, &key); 227 if (!real_pos) 228 return false; 229 key = *real_pos; 230 *real = bpf_map_lookup_elem(&reals, &key); 231 if (!(*real)) 232 return false; 233 return true; 234 } 235 236 static int parse_icmpv6(void *data, void *data_end, __u64 off, 237 struct packet_description *pckt) 238 { 239 struct icmp6hdr *icmp_hdr; 240 struct ipv6hdr *ip6h; 241 242 icmp_hdr = data + off; 243 if (icmp_hdr + 1 > data_end) 244 return TC_ACT_SHOT; 245 if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG) 246 return TC_ACT_OK; 247 off += sizeof(struct icmp6hdr); 248 ip6h = data + off; 249 if (ip6h + 1 > data_end) 250 return TC_ACT_SHOT; 251 pckt->proto = ip6h->nexthdr; 252 pckt->flags |= F_ICMP; 253 memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16); 254 memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16); 255 return TC_ACT_UNSPEC; 256 } 257 258 static int parse_icmp(void *data, void *data_end, __u64 off, 259 struct packet_description *pckt) 260 { 261 struct icmphdr *icmp_hdr; 262 struct iphdr *iph; 263 264 icmp_hdr = data + off; 265 if (icmp_hdr + 1 > data_end) 266 return TC_ACT_SHOT; 267 if (icmp_hdr->type != ICMP_DEST_UNREACH || 268 icmp_hdr->code != ICMP_FRAG_NEEDED) 269 return TC_ACT_OK; 270 off += sizeof(struct icmphdr); 271 iph = data + off; 272 if (iph + 1 > data_end) 273 return TC_ACT_SHOT; 274 if (iph->ihl != 5) 275 return TC_ACT_SHOT; 276 pckt->proto = iph->protocol; 277 pckt->flags |= F_ICMP; 278 pckt->src = iph->daddr; 279 pckt->dst = iph->saddr; 280 return TC_ACT_UNSPEC; 281 } 282 283 static bool parse_udp(void *data, __u64 off, void *data_end, 284 struct packet_description *pckt) 285 { 286 struct udphdr *udp; 287 udp = data + off; 288 289 if (udp + 1 > data_end) 290 return false; 291 292 if (!(pckt->flags & F_ICMP)) { 293 pckt->port16[0] = udp->source; 294 pckt->port16[1] = udp->dest; 295 } else { 296 pckt->port16[0] = udp->dest; 297 pckt->port16[1] = udp->source; 298 } 299 return true; 300 } 301 302 static bool parse_tcp(void *data, __u64 off, void *data_end, 303 struct packet_description *pckt) 304 { 305 struct tcphdr *tcp; 306 307 tcp = data + off; 308 if (tcp + 1 > data_end) 309 return false; 310 311 if (tcp->syn) 312 pckt->flags |= F_SYN_SET; 313 314 if (!(pckt->flags & F_ICMP)) { 315 pckt->port16[0] = tcp->source; 316 pckt->port16[1] = tcp->dest; 317 } else { 318 pckt->port16[0] = tcp->dest; 319 pckt->port16[1] = tcp->source; 320 } 321 return true; 322 } 323 324 static int process_packet(void *data, __u64 off, void *data_end, 325 bool is_ipv6, struct __sk_buff *skb) 326 { 327 void *pkt_start = (void *)(long)skb->data; 328 struct packet_description pckt = {}; 329 struct eth_hdr *eth = pkt_start; 330 struct bpf_tunnel_key tkey = {}; 331 struct vip_stats *data_stats; 332 struct real_definition *dst; 333 struct vip_meta *vip_info; 334 struct ctl_value *cval; 335 __u32 v4_intf_pos = 1; 336 __u32 v6_intf_pos = 2; 337 struct ipv6hdr *ip6h; 338 struct vip vip = {}; 339 struct iphdr *iph; 340 int tun_flag = 0; 341 __u16 pkt_bytes; 342 __u64 iph_len; 343 __u32 ifindex; 344 __u8 protocol; 345 __u32 vip_num; 346 int action; 347 348 tkey.tunnel_ttl = 64; 349 if (is_ipv6) { 350 ip6h = data + off; 351 if (ip6h + 1 > data_end) 352 return TC_ACT_SHOT; 353 354 iph_len = sizeof(struct ipv6hdr); 355 protocol = ip6h->nexthdr; 356 pckt.proto = protocol; 357 pkt_bytes = bpf_ntohs(ip6h->payload_len); 358 off += iph_len; 359 if (protocol == IPPROTO_FRAGMENT) { 360 return TC_ACT_SHOT; 361 } else if (protocol == IPPROTO_ICMPV6) { 362 action = parse_icmpv6(data, data_end, off, &pckt); 363 if (action >= 0) 364 return action; 365 off += IPV6_PLUS_ICMP_HDR; 366 } else { 367 memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16); 368 memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16); 369 } 370 } else { 371 iph = data + off; 372 if (iph + 1 > data_end) 373 return TC_ACT_SHOT; 374 if (iph->ihl != 5) 375 return TC_ACT_SHOT; 376 377 protocol = iph->protocol; 378 pckt.proto = protocol; 379 pkt_bytes = bpf_ntohs(iph->tot_len); 380 off += IPV4_HDR_LEN_NO_OPT; 381 382 if (iph->frag_off & PCKT_FRAGMENTED) 383 return TC_ACT_SHOT; 384 if (protocol == IPPROTO_ICMP) { 385 action = parse_icmp(data, data_end, off, &pckt); 386 if (action >= 0) 387 return action; 388 off += IPV4_PLUS_ICMP_HDR; 389 } else { 390 pckt.src = iph->saddr; 391 pckt.dst = iph->daddr; 392 } 393 } 394 protocol = pckt.proto; 395 396 if (protocol == IPPROTO_TCP) { 397 if (!parse_tcp(data, off, data_end, &pckt)) 398 return TC_ACT_SHOT; 399 } else if (protocol == IPPROTO_UDP) { 400 if (!parse_udp(data, off, data_end, &pckt)) 401 return TC_ACT_SHOT; 402 } else { 403 return TC_ACT_SHOT; 404 } 405 406 if (is_ipv6) 407 memcpy(vip.daddr.v6, pckt.dstv6, 16); 408 else 409 vip.daddr.v4 = pckt.dst; 410 411 vip.dport = pckt.port16[1]; 412 vip.protocol = pckt.proto; 413 vip_info = bpf_map_lookup_elem(&vip_map, &vip); 414 if (!vip_info) { 415 vip.dport = 0; 416 vip_info = bpf_map_lookup_elem(&vip_map, &vip); 417 if (!vip_info) 418 return TC_ACT_SHOT; 419 pckt.port16[1] = 0; 420 } 421 422 if (vip_info->flags & F_HASH_NO_SRC_PORT) 423 pckt.port16[0] = 0; 424 425 if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6)) 426 return TC_ACT_SHOT; 427 428 if (dst->flags & F_IPV6) { 429 cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos); 430 if (!cval) 431 return TC_ACT_SHOT; 432 ifindex = cval->ifindex; 433 memcpy(tkey.remote_ipv6, dst->dstv6, 16); 434 tun_flag = BPF_F_TUNINFO_IPV6; 435 } else { 436 cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos); 437 if (!cval) 438 return TC_ACT_SHOT; 439 ifindex = cval->ifindex; 440 tkey.remote_ipv4 = dst->dst; 441 } 442 vip_num = vip_info->vip_num; 443 data_stats = bpf_map_lookup_elem(&stats, &vip_num); 444 if (!data_stats) 445 return TC_ACT_SHOT; 446 data_stats->pkts++; 447 data_stats->bytes += pkt_bytes; 448 bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag); 449 *(u32 *)eth->eth_dest = tkey.remote_ipv4; 450 return bpf_redirect(ifindex, 0); 451 } 452 453 SEC("l4lb-demo") 454 int balancer_ingress(struct __sk_buff *ctx) 455 { 456 void *data_end = (void *)(long)ctx->data_end; 457 void *data = (void *)(long)ctx->data; 458 struct eth_hdr *eth = data; 459 __u32 eth_proto; 460 __u32 nh_off; 461 462 nh_off = sizeof(struct eth_hdr); 463 if (data + nh_off > data_end) 464 return TC_ACT_SHOT; 465 eth_proto = eth->eth_proto; 466 if (eth_proto == bpf_htons(ETH_P_IP)) 467 return process_packet(data, nh_off, data_end, false, ctx); 468 else if (eth_proto == bpf_htons(ETH_P_IPV6)) 469 return process_packet(data, nh_off, data_end, true, ctx); 470 else 471 return TC_ACT_SHOT; 472 } 473 char _license[] SEC("license") = "GPL"; 474