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