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