linux/tools/testing/selftests/bpf/progs/test_l4lb.c
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   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
  24int _version SEC("version") = 1;
  25
  26static inline __u32 rol32(__u32 word, unsigned int shift)
  27{
  28        return (word << shift) | (word >> ((-shift) & 31));
  29}
  30
  31/* copy paste of jhash from kernel sources to make sure llvm
  32 * can compile it into valid sequence of bpf instructions
  33 */
  34#define __jhash_mix(a, b, c)                    \
  35{                                               \
  36        a -= c;  a ^= rol32(c, 4);  c += b;     \
  37        b -= a;  b ^= rol32(a, 6);  a += c;     \
  38        c -= b;  c ^= rol32(b, 8);  b += a;     \
  39        a -= c;  a ^= rol32(c, 16); c += b;     \
  40        b -= a;  b ^= rol32(a, 19); a += c;     \
  41        c -= b;  c ^= rol32(b, 4);  b += a;     \
  42}
  43
  44#define __jhash_final(a, b, c)                  \
  45{                                               \
  46        c ^= b; c -= rol32(b, 14);              \
  47        a ^= c; a -= rol32(c, 11);              \
  48        b ^= a; b -= rol32(a, 25);              \
  49        c ^= b; c -= rol32(b, 16);              \
  50        a ^= c; a -= rol32(c, 4);               \
  51        b ^= a; b -= rol32(a, 14);              \
  52        c ^= b; c -= rol32(b, 24);              \
  53}
  54
  55#define JHASH_INITVAL           0xdeadbeef
  56
  57typedef unsigned int u32;
  58
  59static inline u32 jhash(const void *key, u32 length, u32 initval)
  60{
  61        u32 a, b, c;
  62        const unsigned char *k = key;
  63
  64        a = b = c = JHASH_INITVAL + length + initval;
  65
  66        while (length > 12) {
  67                a += *(u32 *)(k);
  68                b += *(u32 *)(k + 4);
  69                c += *(u32 *)(k + 8);
  70                __jhash_mix(a, b, c);
  71                length -= 12;
  72                k += 12;
  73        }
  74        switch (length) {
  75        case 12: c += (u32)k[11]<<24;
  76        case 11: c += (u32)k[10]<<16;
  77        case 10: c += (u32)k[9]<<8;
  78        case 9:  c += k[8];
  79        case 8:  b += (u32)k[7]<<24;
  80        case 7:  b += (u32)k[6]<<16;
  81        case 6:  b += (u32)k[5]<<8;
  82        case 5:  b += k[4];
  83        case 4:  a += (u32)k[3]<<24;
  84        case 3:  a += (u32)k[2]<<16;
  85        case 2:  a += (u32)k[1]<<8;
  86        case 1:  a += k[0];
  87                 __jhash_final(a, b, c);
  88        case 0: /* Nothing left to add */
  89                break;
  90        }
  91
  92        return c;
  93}
  94
  95static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
  96{
  97        a += initval;
  98        b += initval;
  99        c += initval;
 100        __jhash_final(a, b, c);
 101        return c;
 102}
 103
 104static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
 105{
 106        return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
 107}
 108
 109#define PCKT_FRAGMENTED 65343
 110#define IPV4_HDR_LEN_NO_OPT 20
 111#define IPV4_PLUS_ICMP_HDR 28
 112#define IPV6_PLUS_ICMP_HDR 48
 113#define RING_SIZE 2
 114#define MAX_VIPS 12
 115#define MAX_REALS 5
 116#define CTL_MAP_SIZE 16
 117#define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE)
 118#define F_IPV6 (1 << 0)
 119#define F_HASH_NO_SRC_PORT (1 << 0)
 120#define F_ICMP (1 << 0)
 121#define F_SYN_SET (1 << 1)
 122
 123struct packet_description {
 124        union {
 125                __be32 src;
 126                __be32 srcv6[4];
 127        };
 128        union {
 129                __be32 dst;
 130                __be32 dstv6[4];
 131        };
 132        union {
 133                __u32 ports;
 134                __u16 port16[2];
 135        };
 136        __u8 proto;
 137        __u8 flags;
 138};
 139
 140struct ctl_value {
 141        union {
 142                __u64 value;
 143                __u32 ifindex;
 144                __u8 mac[6];
 145        };
 146};
 147
 148struct vip_meta {
 149        __u32 flags;
 150        __u32 vip_num;
 151};
 152
 153struct real_definition {
 154        union {
 155                __be32 dst;
 156                __be32 dstv6[4];
 157        };
 158        __u8 flags;
 159};
 160
 161struct vip_stats {
 162        __u64 bytes;
 163        __u64 pkts;
 164};
 165
 166struct eth_hdr {
 167        unsigned char eth_dest[ETH_ALEN];
 168        unsigned char eth_source[ETH_ALEN];
 169        unsigned short eth_proto;
 170};
 171
 172struct {
 173        __uint(type, BPF_MAP_TYPE_HASH);
 174        __uint(max_entries, MAX_VIPS);
 175        __type(key, struct vip);
 176        __type(value, struct vip_meta);
 177} vip_map SEC(".maps");
 178
 179struct {
 180        __uint(type, BPF_MAP_TYPE_ARRAY);
 181        __uint(max_entries, CH_RINGS_SIZE);
 182        __type(key, __u32);
 183        __type(value, __u32);
 184} ch_rings SEC(".maps");
 185
 186struct {
 187        __uint(type, BPF_MAP_TYPE_ARRAY);
 188        __uint(max_entries, MAX_REALS);
 189        __type(key, __u32);
 190        __type(value, struct real_definition);
 191} reals SEC(".maps");
 192
 193struct {
 194        __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
 195        __uint(max_entries, MAX_VIPS);
 196        __type(key, __u32);
 197        __type(value, struct vip_stats);
 198} stats SEC(".maps");
 199
 200struct {
 201        __uint(type, BPF_MAP_TYPE_ARRAY);
 202        __uint(max_entries, CTL_MAP_SIZE);
 203        __type(key, __u32);
 204        __type(value, struct ctl_value);
 205} ctl_array SEC(".maps");
 206
 207static __always_inline __u32 get_packet_hash(struct packet_description *pckt,
 208                                             bool ipv6)
 209{
 210        if (ipv6)
 211                return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS),
 212                                    pckt->ports, CH_RINGS_SIZE);
 213        else
 214                return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE);
 215}
 216
 217static __always_inline bool get_packet_dst(struct real_definition **real,
 218                                           struct packet_description *pckt,
 219                                           struct vip_meta *vip_info,
 220                                           bool is_ipv6)
 221{
 222        __u32 hash = get_packet_hash(pckt, is_ipv6) % RING_SIZE;
 223        __u32 key = RING_SIZE * vip_info->vip_num + hash;
 224        __u32 *real_pos;
 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
 236static __always_inline 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
 258static __always_inline 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
 283static __always_inline 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
 302static __always_inline 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
 324static __always_inline 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
 453SEC("l4lb-demo")
 454int 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}
 473char _license[] SEC("license") = "GPL";
 474