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   1 /*
   2  * net/sched/cls_flow.c         Generic flow classifier
   3  *
   4  * Copyright (c) 2007, 2008 Patrick McHardy <kaber@trash.net>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/list.h>
  15 #include <linux/jhash.h>
  16 #include <linux/random.h>
  17 #include <linux/pkt_cls.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/in.h>
  20 #include <linux/ip.h>
  21 #include <linux/ipv6.h>
  22
  23 #include <net/pkt_cls.h>
  24 #include <net/ip.h>
  25 #include <net/route.h>
  26 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  27 #include <net/netfilter/nf_conntrack.h>
  28 #endif
  29
  30 struct flow_head {
  31         struct list_head        filters;
  32 };
  33
  34 struct flow_filter {
  35         struct list_head        list;
  36         struct tcf_exts         exts;
  37         struct tcf_ematch_tree  ematches;
  38         u32                     handle;
  39
  40         u32                     nkeys;
  41         u32                     keymask;
  42         u32                     mode;
  43         u32                     mask;
  44         u32                     xor;
  45         u32                     rshift;
  46         u32                     addend;
  47         u32                     divisor;
  48         u32                     baseclass;
  49 };
  50
  51 static u32 flow_hashrnd __read_mostly;
  52 static int flow_hashrnd_initted __read_mostly;
  53
  54 static const struct tcf_ext_map flow_ext_map = {
  55         .action = TCA_FLOW_ACT,
  56         .police = TCA_FLOW_POLICE,
  57 };
  58
  59 static inline u32 addr_fold(void *addr)
  60 {
  61         unsigned long a = (unsigned long)addr;
  62
  63         return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0);
  64 }
  65
  66 static u32 flow_get_src(const struct sk_buff *skb)
  67 {
  68         switch (skb->protocol) {
  69         case __constant_htons(ETH_P_IP):
  70                 return ntohl(ip_hdr(skb)->saddr);
  71         case __constant_htons(ETH_P_IPV6):
  72                 return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]);
  73         default:
  74                 return addr_fold(skb->sk);
  75         }
  76 }
  77
  78 static u32 flow_get_dst(const struct sk_buff *skb)
  79 {
  80         switch (skb->protocol) {
  81         case __constant_htons(ETH_P_IP):
  82                 return ntohl(ip_hdr(skb)->daddr);
  83         case __constant_htons(ETH_P_IPV6):
  84                 return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]);
  85         default:
  86                 return addr_fold(skb->dst) ^ (__force u16)skb->protocol;
  87         }
  88 }
  89
  90 static u32 flow_get_proto(const struct sk_buff *skb)
  91 {
  92         switch (skb->protocol) {
  93         case __constant_htons(ETH_P_IP):
  94                 return ip_hdr(skb)->protocol;
  95         case __constant_htons(ETH_P_IPV6):
  96                 return ipv6_hdr(skb)->nexthdr;
  97         default:
  98                 return 0;
  99         }
 100 }
 101
 102 static int has_ports(u8 protocol)
 103 {
 104         switch (protocol) {
 105         case IPPROTO_TCP:
 106         case IPPROTO_UDP:
 107         case IPPROTO_UDPLITE:
 108         case IPPROTO_SCTP:
 109         case IPPROTO_DCCP:
 110         case IPPROTO_ESP:
 111                 return 1;
 112         default:
 113                 return 0;
 114         }
 115 }
 116
 117 static u32 flow_get_proto_src(const struct sk_buff *skb)
 118 {
 119         u32 res = 0;
 120
 121         switch (skb->protocol) {
 122         case __constant_htons(ETH_P_IP): {
 123                 struct iphdr *iph = ip_hdr(skb);
 124
 125                 if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
 126                     has_ports(iph->protocol))
 127                         res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4));
 128                 break;
 129         }
 130         case __constant_htons(ETH_P_IPV6): {
 131                 struct ipv6hdr *iph = ipv6_hdr(skb);
 132
 133                 if (has_ports(iph->nexthdr))
 134                         res = ntohs(*(__be16 *)&iph[1]);
 135                 break;
 136         }
 137         default:
 138                 res = addr_fold(skb->sk);
 139         }
 140
 141         return res;
 142 }
 143
 144 static u32 flow_get_proto_dst(const struct sk_buff *skb)
 145 {
 146         u32 res = 0;
 147
 148         switch (skb->protocol) {
 149         case __constant_htons(ETH_P_IP): {
 150                 struct iphdr *iph = ip_hdr(skb);
 151
 152                 if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) &&
 153                     has_ports(iph->protocol))
 154                         res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + 2));
 155                 break;
 156         }
 157         case __constant_htons(ETH_P_IPV6): {
 158                 struct ipv6hdr *iph = ipv6_hdr(skb);
 159
 160                 if (has_ports(iph->nexthdr))
 161                         res = ntohs(*(__be16 *)((void *)&iph[1] + 2));
 162                 break;
 163         }
 164         default:
 165                 res = addr_fold(skb->dst) ^ (__force u16)skb->protocol;
 166         }
 167
 168         return res;
 169 }
 170
 171 static u32 flow_get_iif(const struct sk_buff *skb)
 172 {
 173         return skb->iif;
 174 }
 175
 176 static u32 flow_get_priority(const struct sk_buff *skb)
 177 {
 178         return skb->priority;
 179 }
 180
 181 static u32 flow_get_mark(const struct sk_buff *skb)
 182 {
 183         return skb->mark;
 184 }
 185
 186 static u32 flow_get_nfct(const struct sk_buff *skb)
 187 {
 188 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 189         return addr_fold(skb->nfct);
 190 #else
 191         return 0;
 192 #endif
 193 }
 194
 195 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 196 #define CTTUPLE(skb, member)                                            \
 197 ({                                                                      \
 198         enum ip_conntrack_info ctinfo;                                  \
 199         struct nf_conn *ct = nf_ct_get(skb, &ctinfo);                   \
 200         if (ct == NULL)                                                 \
 201                 goto fallback;                                          \
 202         ct->tuplehash[CTINFO2DIR(ctinfo)].tuple.member;                 \
 203 })
 204 #else
 205 #define CTTUPLE(skb, member)                                            \
 206 ({                                                                      \
 207         goto fallback;                                                  \
 208         0;                                                              \
 209 })
 210 #endif
 211
 212 static u32 flow_get_nfct_src(const struct sk_buff *skb)
 213 {
 214         switch (skb->protocol) {
 215         case __constant_htons(ETH_P_IP):
 216                 return ntohl(CTTUPLE(skb, src.u3.ip));
 217         case __constant_htons(ETH_P_IPV6):
 218                 return ntohl(CTTUPLE(skb, src.u3.ip6[3]));
 219         }
 220 fallback:
 221         return flow_get_src(skb);
 222 }
 223
 224 static u32 flow_get_nfct_dst(const struct sk_buff *skb)
 225 {
 226         switch (skb->protocol) {
 227         case __constant_htons(ETH_P_IP):
 228                 return ntohl(CTTUPLE(skb, dst.u3.ip));
 229         case __constant_htons(ETH_P_IPV6):
 230                 return ntohl(CTTUPLE(skb, dst.u3.ip6[3]));
 231         }
 232 fallback:
 233         return flow_get_dst(skb);
 234 }
 235
 236 static u32 flow_get_nfct_proto_src(const struct sk_buff *skb)
 237 {
 238         return ntohs(CTTUPLE(skb, src.u.all));
 239 fallback:
 240         return flow_get_proto_src(skb);
 241 }
 242
 243 static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb)
 244 {
 245         return ntohs(CTTUPLE(skb, dst.u.all));
 246 fallback:
 247         return flow_get_proto_dst(skb);
 248 }
 249
 250 static u32 flow_get_rtclassid(const struct sk_buff *skb)
 251 {
 252 #ifdef CONFIG_NET_CLS_ROUTE
 253         if (skb->dst)
 254                 return skb->dst->tclassid;
 255 #endif
 256         return 0;
 257 }
 258
 259 static u32 flow_get_skuid(const struct sk_buff *skb)
 260 {
 261         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
 262                 return skb->sk->sk_socket->file->f_uid;
 263         return 0;
 264 }
 265
 266 static u32 flow_get_skgid(const struct sk_buff *skb)
 267 {
 268         if (skb->sk && skb->sk->sk_socket && skb->sk->sk_socket->file)
 269                 return skb->sk->sk_socket->file->f_gid;
 270         return 0;
 271 }
 272
 273 static u32 flow_key_get(const struct sk_buff *skb, int key)
 274 {
 275         switch (key) {
 276         case FLOW_KEY_SRC:
 277                 return flow_get_src(skb);
 278         case FLOW_KEY_DST:
 279                 return flow_get_dst(skb);
 280         case FLOW_KEY_PROTO:
 281                 return flow_get_proto(skb);
 282         case FLOW_KEY_PROTO_SRC:
 283                 return flow_get_proto_src(skb);
 284         case FLOW_KEY_PROTO_DST:
 285                 return flow_get_proto_dst(skb);
 286         case FLOW_KEY_IIF:
 287                 return flow_get_iif(skb);
 288         case FLOW_KEY_PRIORITY:
 289                 return flow_get_priority(skb);
 290         case FLOW_KEY_MARK:
 291                 return flow_get_mark(skb);
 292         case FLOW_KEY_NFCT:
 293                 return flow_get_nfct(skb);
 294         case FLOW_KEY_NFCT_SRC:
 295                 return flow_get_nfct_src(skb);
 296         case FLOW_KEY_NFCT_DST:
 297                 return flow_get_nfct_dst(skb);
 298         case FLOW_KEY_NFCT_PROTO_SRC:
 299                 return flow_get_nfct_proto_src(skb);
 300         case FLOW_KEY_NFCT_PROTO_DST:
 301                 return flow_get_nfct_proto_dst(skb);
 302         case FLOW_KEY_RTCLASSID:
 303                 return flow_get_rtclassid(skb);
 304         case FLOW_KEY_SKUID:
 305                 return flow_get_skuid(skb);
 306         case FLOW_KEY_SKGID:
 307                 return flow_get_skgid(skb);
 308         default:
 309                 WARN_ON(1);
 310                 return 0;
 311         }
 312 }
 313
 314 static int flow_classify(struct sk_buff *skb, struct tcf_proto *tp,
 315                          struct tcf_result *res)
 316 {
 317         struct flow_head *head = tp->root;
 318         struct flow_filter *f;
 319         u32 keymask;
 320         u32 classid;
 321         unsigned int n, key;
 322         int r;
 323
 324         list_for_each_entry(f, &head->filters, list) {
 325                 u32 keys[f->nkeys];
 326
 327                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
 328                         continue;
 329
 330                 keymask = f->keymask;
 331
 332                 for (n = 0; n < f->nkeys; n++) {
 333                         key = ffs(keymask) - 1;
 334                         keymask &= ~(1 << key);
 335                         keys[n] = flow_key_get(skb, key);
 336                 }
 337
 338                 if (f->mode == FLOW_MODE_HASH)
 339                         classid = jhash2(keys, f->nkeys, flow_hashrnd);
 340                 else {
 341                         classid = keys[0];
 342                         classid = (classid & f->mask) ^ f->xor;
 343                         classid = (classid >> f->rshift) + f->addend;
 344                 }
 345
 346                 if (f->divisor)
 347                         classid %= f->divisor;
 348
 349                 res->class   = 0;
 350                 res->classid = TC_H_MAKE(f->baseclass, f->baseclass + classid);
 351
 352                 r = tcf_exts_exec(skb, &f->exts, res);
 353                 if (r < 0)
 354                         continue;
 355                 return r;
 356         }
 357         return -1;
 358 }
 359
 360 static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = {
 361         [TCA_FLOW_KEYS]         = { .type = NLA_U32 },
 362         [TCA_FLOW_MODE]         = { .type = NLA_U32 },
 363         [TCA_FLOW_BASECLASS]    = { .type = NLA_U32 },
 364         [TCA_FLOW_RSHIFT]       = { .type = NLA_U32 },
 365         [TCA_FLOW_ADDEND]       = { .type = NLA_U32 },
 366         [TCA_FLOW_MASK]         = { .type = NLA_U32 },
 367         [TCA_FLOW_XOR]          = { .type = NLA_U32 },
 368         [TCA_FLOW_DIVISOR]      = { .type = NLA_U32 },
 369         [TCA_FLOW_ACT]          = { .type = NLA_NESTED },
 370         [TCA_FLOW_POLICE]       = { .type = NLA_NESTED },
 371         [TCA_FLOW_EMATCHES]     = { .type = NLA_NESTED },
 372 };
 373
 374 static int flow_change(struct tcf_proto *tp, unsigned long base,
 375                        u32 handle, struct nlattr **tca,
 376                        unsigned long *arg)
 377 {
 378         struct flow_head *head = tp->root;
 379         struct flow_filter *f;
 380         struct nlattr *opt = tca[TCA_OPTIONS];
 381         struct nlattr *tb[TCA_FLOW_MAX + 1];
 382         struct tcf_exts e;
 383         struct tcf_ematch_tree t;
 384         unsigned int nkeys = 0;
 385         u32 baseclass = 0;
 386         u32 keymask = 0;
 387         u32 mode;
 388         int err;
 389
 390         if (opt == NULL)
 391                 return -EINVAL;
 392
 393         err = nla_parse_nested(tb, TCA_FLOW_MAX, opt, flow_policy);
 394         if (err < 0)
 395                 return err;
 396
 397         if (tb[TCA_FLOW_BASECLASS]) {
 398                 baseclass = nla_get_u32(tb[TCA_FLOW_BASECLASS]);
 399                 if (TC_H_MIN(baseclass) == 0)
 400                         return -EINVAL;
 401         }
 402
 403         if (tb[TCA_FLOW_KEYS]) {
 404                 keymask = nla_get_u32(tb[TCA_FLOW_KEYS]);
 405
 406                 nkeys = hweight32(keymask);
 407                 if (nkeys == 0)
 408                         return -EINVAL;
 409
 410                 if (fls(keymask) - 1 > FLOW_KEY_MAX)
 411                         return -EOPNOTSUPP;
 412         }
 413
 414         err = tcf_exts_validate(tp, tb, tca[TCA_RATE], &e, &flow_ext_map);
 415         if (err < 0)
 416                 return err;
 417
 418         err = tcf_em_tree_validate(tp, tb[TCA_FLOW_EMATCHES], &t);
 419         if (err < 0)
 420                 goto err1;
 421
 422         f = (struct flow_filter *)*arg;
 423         if (f != NULL) {
 424                 err = -EINVAL;
 425                 if (f->handle != handle && handle)
 426                         goto err2;
 427
 428                 mode = f->mode;
 429                 if (tb[TCA_FLOW_MODE])
 430                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 431                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 432                         goto err2;
 433         } else {
 434                 err = -EINVAL;
 435                 if (!handle)
 436                         goto err2;
 437                 if (!tb[TCA_FLOW_KEYS])
 438                         goto err2;
 439
 440                 mode = FLOW_MODE_MAP;
 441                 if (tb[TCA_FLOW_MODE])
 442                         mode = nla_get_u32(tb[TCA_FLOW_MODE]);
 443                 if (mode != FLOW_MODE_HASH && nkeys > 1)
 444                         goto err2;
 445
 446                 if (TC_H_MAJ(baseclass) == 0)
 447                         baseclass = TC_H_MAKE(tp->q->handle, baseclass);
 448                 if (TC_H_MIN(baseclass) == 0)
 449                         baseclass = TC_H_MAKE(baseclass, 1);
 450
 451                 err = -ENOBUFS;
 452                 f = kzalloc(sizeof(*f), GFP_KERNEL);
 453                 if (f == NULL)
 454                         goto err2;
 455
 456                 f->handle = handle;
 457                 f->mask   = ~0U;
 458         }
 459
 460         tcf_exts_change(tp, &f->exts, &e);
 461         tcf_em_tree_change(tp, &f->ematches, &t);
 462
 463         tcf_tree_lock(tp);
 464
 465         if (tb[TCA_FLOW_KEYS]) {
 466                 f->keymask = keymask;
 467                 f->nkeys   = nkeys;
 468         }
 469
 470         f->mode = mode;
 471
 472         if (tb[TCA_FLOW_MASK])
 473                 f->mask = nla_get_u32(tb[TCA_FLOW_MASK]);
 474         if (tb[TCA_FLOW_XOR])
 475                 f->xor = nla_get_u32(tb[TCA_FLOW_XOR]);
 476         if (tb[TCA_FLOW_RSHIFT])
 477                 f->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]);
 478         if (tb[TCA_FLOW_ADDEND])
 479                 f->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]);
 480
 481         if (tb[TCA_FLOW_DIVISOR])
 482                 f->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]);
 483         if (baseclass)
 484                 f->baseclass = baseclass;
 485
 486         if (*arg == 0)
 487                 list_add_tail(&f->list, &head->filters);
 488
 489         tcf_tree_unlock(tp);
 490
 491         *arg = (unsigned long)f;
 492         return 0;
 493
 494 err2:
 495         tcf_em_tree_destroy(tp, &t);
 496 err1:
 497         tcf_exts_destroy(tp, &e);
 498         return err;
 499 }
 500
 501 static void flow_destroy_filter(struct tcf_proto *tp, struct flow_filter *f)
 502 {
 503         tcf_exts_destroy(tp, &f->exts);
 504         tcf_em_tree_destroy(tp, &f->ematches);
 505         kfree(f);
 506 }
 507
 508 static int flow_delete(struct tcf_proto *tp, unsigned long arg)
 509 {
 510         struct flow_filter *f = (struct flow_filter *)arg;
 511
 512         tcf_tree_lock(tp);
 513         list_del(&f->list);
 514         tcf_tree_unlock(tp);
 515         flow_destroy_filter(tp, f);
 516         return 0;
 517 }
 518
 519 static int flow_init(struct tcf_proto *tp)
 520 {
 521         struct flow_head *head;
 522
 523         if (!flow_hashrnd_initted) {
 524                 get_random_bytes(&flow_hashrnd, 4);
 525                 flow_hashrnd_initted = 1;
 526         }
 527
 528         head = kzalloc(sizeof(*head), GFP_KERNEL);
 529         if (head == NULL)
 530                 return -ENOBUFS;
 531         INIT_LIST_HEAD(&head->filters);
 532         tp->root = head;
 533         return 0;
 534 }
 535
 536 static void flow_destroy(struct tcf_proto *tp)
 537 {
 538         struct flow_head *head = tp->root;
 539         struct flow_filter *f, *next;
 540
 541         list_for_each_entry_safe(f, next, &head->filters, list) {
 542                 list_del(&f->list);
 543                 flow_destroy_filter(tp, f);
 544         }
 545         kfree(head);
 546 }
 547
 548 static unsigned long flow_get(struct tcf_proto *tp, u32 handle)
 549 {
 550         struct flow_head *head = tp->root;
 551         struct flow_filter *f;
 552
 553         list_for_each_entry(f, &head->filters, list)
 554                 if (f->handle == handle)
 555                         return (unsigned long)f;
 556         return 0;
 557 }
 558
 559 static void flow_put(struct tcf_proto *tp, unsigned long f)
 560 {
 561         return;
 562 }
 563
 564 static int flow_dump(struct tcf_proto *tp, unsigned long fh,
 565                      struct sk_buff *skb, struct tcmsg *t)
 566 {
 567         struct flow_filter *f = (struct flow_filter *)fh;
 568         struct nlattr *nest;
 569
 570         if (f == NULL)
 571                 return skb->len;
 572
 573         t->tcm_handle = f->handle;
 574
 575         nest = nla_nest_start(skb, TCA_OPTIONS);
 576         if (nest == NULL)
 577                 goto nla_put_failure;
 578
 579         NLA_PUT_U32(skb, TCA_FLOW_KEYS, f->keymask);
 580         NLA_PUT_U32(skb, TCA_FLOW_MODE, f->mode);
 581
 582         if (f->mask != ~0 || f->xor != 0) {
 583                 NLA_PUT_U32(skb, TCA_FLOW_MASK, f->mask);
 584                 NLA_PUT_U32(skb, TCA_FLOW_XOR, f->xor);
 585         }
 586         if (f->rshift)
 587                 NLA_PUT_U32(skb, TCA_FLOW_RSHIFT, f->rshift);
 588         if (f->addend)
 589                 NLA_PUT_U32(skb, TCA_FLOW_ADDEND, f->addend);
 590
 591         if (f->divisor)
 592                 NLA_PUT_U32(skb, TCA_FLOW_DIVISOR, f->divisor);
 593         if (f->baseclass)
 594                 NLA_PUT_U32(skb, TCA_FLOW_BASECLASS, f->baseclass);
 595
 596         if (tcf_exts_dump(skb, &f->exts, &flow_ext_map) < 0)
 597                 goto nla_put_failure;
 598 #ifdef CONFIG_NET_EMATCH
 599         if (f->ematches.hdr.nmatches &&
 600             tcf_em_tree_dump(skb, &f->ematches, TCA_FLOW_EMATCHES) < 0)
 601                 goto nla_put_failure;
 602 #endif
 603         nla_nest_end(skb, nest);
 604
 605         if (tcf_exts_dump_stats(skb, &f->exts, &flow_ext_map) < 0)
 606                 goto nla_put_failure;
 607
 608         return skb->len;
 609
 610 nla_put_failure:
 611         nlmsg_trim(skb, nest);
 612         return -1;
 613 }
 614
 615 static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 616 {
 617         struct flow_head *head = tp->root;
 618         struct flow_filter *f;
 619
 620         list_for_each_entry(f, &head->filters, list) {
 621                 if (arg->count < arg->skip)
 622                         goto skip;
 623                 if (arg->fn(tp, (unsigned long)f, arg) < 0) {
 624                         arg->stop = 1;
 625                         break;
 626                 }
 627 skip:
 628                 arg->count++;
 629         }
 630 }
 631
 632 static struct tcf_proto_ops cls_flow_ops __read_mostly = {
 633         .kind           = "flow",
 634         .classify       = flow_classify,
 635         .init           = flow_init,
 636         .destroy        = flow_destroy,
 637         .change         = flow_change,
 638         .delete         = flow_delete,
 639         .get            = flow_get,
 640         .put            = flow_put,
 641         .dump           = flow_dump,
 642         .walk           = flow_walk,
 643         .owner          = THIS_MODULE,
 644 };
 645
 646 static int __init cls_flow_init(void)
 647 {
 648         return register_tcf_proto_ops(&cls_flow_ops);
 649 }
 650
 651 static void __exit cls_flow_exit(void)
 652 {
 653         unregister_tcf_proto_ops(&cls_flow_ops);
 654 }
 655
 656 module_init(cls_flow_init);
 657 module_exit(cls_flow_exit);
 658
 659 MODULE_LICENSE("GPL");
 660 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 661 MODULE_DESCRIPTION("TC flow classifier");