1 /* 2 * ip6_flowlabel.c IPv6 flowlabel manager. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 */ 11 12 #include <linux/capability.h> 13 #include <linux/errno.h> 14 #include <linux/types.h> 15 #include <linux/socket.h> 16 #include <linux/net.h> 17 #include <linux/netdevice.h> 18 #include <linux/if_arp.h> 19 #include <linux/in6.h> 20 #include <linux/route.h> 21 #include <linux/proc_fs.h> 22 #include <linux/seq_file.h> 23 24 #include <net/sock.h> 25 26 #include <net/ipv6.h> 27 #include <net/ndisc.h> 28 #include <net/protocol.h> 29 #include <net/ip6_route.h> 30 #include <net/addrconf.h> 31 #include <net/rawv6.h> 32 #include <net/icmp.h> 33 #include <net/transp_v6.h> 34 35 #include <asm/uaccess.h> 36 37 #define FL_MIN_LINGER 6 /* Minimal linger. It is set to 6sec specified 38 in old IPv6 RFC. Well, it was reasonable value. 39 */ 40 #define FL_MAX_LINGER 60 /* Maximal linger timeout */ 41 42 /* FL hash table */ 43 44 #define FL_MAX_PER_SOCK 32 45 #define FL_MAX_SIZE 4096 46 #define FL_HASH_MASK 255 47 #define FL_HASH(l) (ntohl(l)&FL_HASH_MASK) 48 49 static atomic_t fl_size = ATOMIC_INIT(0); 50 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1]; 51 52 static void ip6_fl_gc(unsigned long dummy); 53 static DEFINE_TIMER(ip6_fl_gc_timer, ip6_fl_gc, 0, 0); 54 55 /* FL hash table lock: it protects only of GC */ 56 57 static DEFINE_RWLOCK(ip6_fl_lock); 58 59 /* Big socket sock */ 60 61 static DEFINE_RWLOCK(ip6_sk_fl_lock); 62 63 64 static __inline__ struct ip6_flowlabel * __fl_lookup(__be32 label) 65 { 66 struct ip6_flowlabel *fl; 67 68 for (fl=fl_ht[FL_HASH(label)]; fl; fl = fl->next) { 69 if (fl->label == label) 70 return fl; 71 } 72 return NULL; 73 } 74 75 static struct ip6_flowlabel * fl_lookup(__be32 label) 76 { 77 struct ip6_flowlabel *fl; 78 79 read_lock_bh(&ip6_fl_lock); 80 fl = __fl_lookup(label); 81 if (fl) 82 atomic_inc(&fl->users); 83 read_unlock_bh(&ip6_fl_lock); 84 return fl; 85 } 86 87 88 static void fl_free(struct ip6_flowlabel *fl) 89 { 90 if (fl) 91 kfree(fl->opt); 92 kfree(fl); 93 } 94 95 static void fl_release(struct ip6_flowlabel *fl) 96 { 97 write_lock_bh(&ip6_fl_lock); 98 99 fl->lastuse = jiffies; 100 if (atomic_dec_and_test(&fl->users)) { 101 unsigned long ttd = fl->lastuse + fl->linger; 102 if (time_after(ttd, fl->expires)) 103 fl->expires = ttd; 104 ttd = fl->expires; 105 if (fl->opt && fl->share == IPV6_FL_S_EXCL) { 106 struct ipv6_txoptions *opt = fl->opt; 107 fl->opt = NULL; 108 kfree(opt); 109 } 110 if (!timer_pending(&ip6_fl_gc_timer) || 111 time_after(ip6_fl_gc_timer.expires, ttd)) 112 mod_timer(&ip6_fl_gc_timer, ttd); 113 } 114 115 write_unlock_bh(&ip6_fl_lock); 116 } 117 118 static void ip6_fl_gc(unsigned long dummy) 119 { 120 int i; 121 unsigned long now = jiffies; 122 unsigned long sched = 0; 123 124 write_lock(&ip6_fl_lock); 125 126 for (i=0; i<=FL_HASH_MASK; i++) { 127 struct ip6_flowlabel *fl, **flp; 128 flp = &fl_ht[i]; 129 while ((fl=*flp) != NULL) { 130 if (atomic_read(&fl->users) == 0) { 131 unsigned long ttd = fl->lastuse + fl->linger; 132 if (time_after(ttd, fl->expires)) 133 fl->expires = ttd; 134 ttd = fl->expires; 135 if (time_after_eq(now, ttd)) { 136 *flp = fl->next; 137 fl_free(fl); 138 atomic_dec(&fl_size); 139 continue; 140 } 141 if (!sched || time_before(ttd, sched)) 142 sched = ttd; 143 } 144 flp = &fl->next; 145 } 146 } 147 if (!sched && atomic_read(&fl_size)) 148 sched = now + FL_MAX_LINGER; 149 if (sched) { 150 ip6_fl_gc_timer.expires = sched; 151 add_timer(&ip6_fl_gc_timer); 152 } 153 write_unlock(&ip6_fl_lock); 154 } 155 156 static int fl_intern(struct ip6_flowlabel *fl, __be32 label) 157 { 158 fl->label = label & IPV6_FLOWLABEL_MASK; 159 160 write_lock_bh(&ip6_fl_lock); 161 if (label == 0) { 162 for (;;) { 163 fl->label = htonl(net_random())&IPV6_FLOWLABEL_MASK; 164 if (fl->label) { 165 struct ip6_flowlabel *lfl; 166 lfl = __fl_lookup(fl->label); 167 if (lfl == NULL) 168 break; 169 } 170 } 171 } 172 173 fl->lastuse = jiffies; 174 fl->next = fl_ht[FL_HASH(fl->label)]; 175 fl_ht[FL_HASH(fl->label)] = fl; 176 atomic_inc(&fl_size); 177 write_unlock_bh(&ip6_fl_lock); 178 return 0; 179 } 180 181 182 183 /* Socket flowlabel lists */ 184 185 struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label) 186 { 187 struct ipv6_fl_socklist *sfl; 188 struct ipv6_pinfo *np = inet6_sk(sk); 189 190 label &= IPV6_FLOWLABEL_MASK; 191 192 for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) { 193 struct ip6_flowlabel *fl = sfl->fl; 194 if (fl->label == label) { 195 fl->lastuse = jiffies; 196 atomic_inc(&fl->users); 197 return fl; 198 } 199 } 200 return NULL; 201 } 202 203 EXPORT_SYMBOL_GPL(fl6_sock_lookup); 204 205 void fl6_free_socklist(struct sock *sk) 206 { 207 struct ipv6_pinfo *np = inet6_sk(sk); 208 struct ipv6_fl_socklist *sfl; 209 210 while ((sfl = np->ipv6_fl_list) != NULL) { 211 np->ipv6_fl_list = sfl->next; 212 fl_release(sfl->fl); 213 kfree(sfl); 214 } 215 } 216 217 /* Service routines */ 218 219 220 /* 221 It is the only difficult place. flowlabel enforces equal headers 222 before and including routing header, however user may supply options 223 following rthdr. 224 */ 225 226 struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions * opt_space, 227 struct ip6_flowlabel * fl, 228 struct ipv6_txoptions * fopt) 229 { 230 struct ipv6_txoptions * fl_opt = fl->opt; 231 232 if (fopt == NULL || fopt->opt_flen == 0) 233 return fl_opt; 234 235 if (fl_opt != NULL) { 236 opt_space->hopopt = fl_opt->hopopt; 237 opt_space->dst0opt = fl_opt->dst0opt; 238 opt_space->srcrt = fl_opt->srcrt; 239 opt_space->opt_nflen = fl_opt->opt_nflen; 240 } else { 241 if (fopt->opt_nflen == 0) 242 return fopt; 243 opt_space->hopopt = NULL; 244 opt_space->dst0opt = NULL; 245 opt_space->srcrt = NULL; 246 opt_space->opt_nflen = 0; 247 } 248 opt_space->dst1opt = fopt->dst1opt; 249 opt_space->opt_flen = fopt->opt_flen; 250 return opt_space; 251 } 252 253 static unsigned long check_linger(unsigned long ttl) 254 { 255 if (ttl < FL_MIN_LINGER) 256 return FL_MIN_LINGER*HZ; 257 if (ttl > FL_MAX_LINGER && !capable(CAP_NET_ADMIN)) 258 return 0; 259 return ttl*HZ; 260 } 261 262 static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned long expires) 263 { 264 linger = check_linger(linger); 265 if (!linger) 266 return -EPERM; 267 expires = check_linger(expires); 268 if (!expires) 269 return -EPERM; 270 fl->lastuse = jiffies; 271 if (time_before(fl->linger, linger)) 272 fl->linger = linger; 273 if (time_before(expires, fl->linger)) 274 expires = fl->linger; 275 if (time_before(fl->expires, fl->lastuse + expires)) 276 fl->expires = fl->lastuse + expires; 277 return 0; 278 } 279 280 static struct ip6_flowlabel * 281 fl_create(struct in6_flowlabel_req *freq, char __user *optval, int optlen, int *err_p) 282 { 283 struct ip6_flowlabel *fl; 284 int olen; 285 int addr_type; 286 int err; 287 288 err = -ENOMEM; 289 fl = kzalloc(sizeof(*fl), GFP_KERNEL); 290 if (fl == NULL) 291 goto done; 292 293 olen = optlen - CMSG_ALIGN(sizeof(*freq)); 294 if (olen > 0) { 295 struct msghdr msg; 296 struct flowi flowi; 297 int junk; 298 299 err = -ENOMEM; 300 fl->opt = kmalloc(sizeof(*fl->opt) + olen, GFP_KERNEL); 301 if (fl->opt == NULL) 302 goto done; 303 304 memset(fl->opt, 0, sizeof(*fl->opt)); 305 fl->opt->tot_len = sizeof(*fl->opt) + olen; 306 err = -EFAULT; 307 if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen)) 308 goto done; 309 310 msg.msg_controllen = olen; 311 msg.msg_control = (void*)(fl->opt+1); 312 flowi.oif = 0; 313 314 err = datagram_send_ctl(&msg, &flowi, fl->opt, &junk, &junk); 315 if (err) 316 goto done; 317 err = -EINVAL; 318 if (fl->opt->opt_flen) 319 goto done; 320 if (fl->opt->opt_nflen == 0) { 321 kfree(fl->opt); 322 fl->opt = NULL; 323 } 324 } 325 326 fl->expires = jiffies; 327 err = fl6_renew(fl, freq->flr_linger, freq->flr_expires); 328 if (err) 329 goto done; 330 fl->share = freq->flr_share; 331 addr_type = ipv6_addr_type(&freq->flr_dst); 332 if ((addr_type&IPV6_ADDR_MAPPED) 333 || addr_type == IPV6_ADDR_ANY) { 334 err = -EINVAL; 335 goto done; 336 } 337 ipv6_addr_copy(&fl->dst, &freq->flr_dst); 338 atomic_set(&fl->users, 1); 339 switch (fl->share) { 340 case IPV6_FL_S_EXCL: 341 case IPV6_FL_S_ANY: 342 break; 343 case IPV6_FL_S_PROCESS: 344 fl->owner = current->pid; 345 break; 346 case IPV6_FL_S_USER: 347 fl->owner = current->euid; 348 break; 349 default: 350 err = -EINVAL; 351 goto done; 352 } 353 return fl; 354 355 done: 356 fl_free(fl); 357 *err_p = err; 358 return NULL; 359 } 360 361 static int mem_check(struct sock *sk) 362 { 363 struct ipv6_pinfo *np = inet6_sk(sk); 364 struct ipv6_fl_socklist *sfl; 365 int room = FL_MAX_SIZE - atomic_read(&fl_size); 366 int count = 0; 367 368 if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK) 369 return 0; 370 371 for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) 372 count++; 373 374 if (room <= 0 || 375 ((count >= FL_MAX_PER_SOCK || 376 (count > 0 && room < FL_MAX_SIZE/2) || room < FL_MAX_SIZE/4) 377 && !capable(CAP_NET_ADMIN))) 378 return -ENOBUFS; 379 380 return 0; 381 } 382 383 static int ipv6_hdr_cmp(struct ipv6_opt_hdr *h1, struct ipv6_opt_hdr *h2) 384 { 385 if (h1 == h2) 386 return 0; 387 if (h1 == NULL || h2 == NULL) 388 return 1; 389 if (h1->hdrlen != h2->hdrlen) 390 return 1; 391 return memcmp(h1+1, h2+1, ((h1->hdrlen+1)<<3) - sizeof(*h1)); 392 } 393 394 static int ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2) 395 { 396 if (o1 == o2) 397 return 0; 398 if (o1 == NULL || o2 == NULL) 399 return 1; 400 if (o1->opt_nflen != o2->opt_nflen) 401 return 1; 402 if (ipv6_hdr_cmp(o1->hopopt, o2->hopopt)) 403 return 1; 404 if (ipv6_hdr_cmp(o1->dst0opt, o2->dst0opt)) 405 return 1; 406 if (ipv6_hdr_cmp((struct ipv6_opt_hdr *)o1->srcrt, (struct ipv6_opt_hdr *)o2->srcrt)) 407 return 1; 408 return 0; 409 } 410 411 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) 412 { 413 int err; 414 struct ipv6_pinfo *np = inet6_sk(sk); 415 struct in6_flowlabel_req freq; 416 struct ipv6_fl_socklist *sfl1=NULL; 417 struct ipv6_fl_socklist *sfl, **sflp; 418 struct ip6_flowlabel *fl; 419 420 if (optlen < sizeof(freq)) 421 return -EINVAL; 422 423 if (copy_from_user(&freq, optval, sizeof(freq))) 424 return -EFAULT; 425 426 switch (freq.flr_action) { 427 case IPV6_FL_A_PUT: 428 write_lock_bh(&ip6_sk_fl_lock); 429 for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) { 430 if (sfl->fl->label == freq.flr_label) { 431 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK)) 432 np->flow_label &= ~IPV6_FLOWLABEL_MASK; 433 *sflp = sfl->next; 434 write_unlock_bh(&ip6_sk_fl_lock); 435 fl_release(sfl->fl); 436 kfree(sfl); 437 return 0; 438 } 439 } 440 write_unlock_bh(&ip6_sk_fl_lock); 441 return -ESRCH; 442 443 case IPV6_FL_A_RENEW: 444 read_lock_bh(&ip6_sk_fl_lock); 445 for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) { 446 if (sfl->fl->label == freq.flr_label) { 447 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires); 448 read_unlock_bh(&ip6_sk_fl_lock); 449 return err; 450 } 451 } 452 read_unlock_bh(&ip6_sk_fl_lock); 453 454 if (freq.flr_share == IPV6_FL_S_NONE && capable(CAP_NET_ADMIN)) { 455 fl = fl_lookup(freq.flr_label); 456 if (fl) { 457 err = fl6_renew(fl, freq.flr_linger, freq.flr_expires); 458 fl_release(fl); 459 return err; 460 } 461 } 462 return -ESRCH; 463 464 case IPV6_FL_A_GET: 465 if (freq.flr_label & ~IPV6_FLOWLABEL_MASK) 466 return -EINVAL; 467 468 fl = fl_create(&freq, optval, optlen, &err); 469 if (fl == NULL) 470 return err; 471 sfl1 = kmalloc(sizeof(*sfl1), GFP_KERNEL); 472 473 if (freq.flr_label) { 474 struct ip6_flowlabel *fl1 = NULL; 475 476 err = -EEXIST; 477 read_lock_bh(&ip6_sk_fl_lock); 478 for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) { 479 if (sfl->fl->label == freq.flr_label) { 480 if (freq.flr_flags&IPV6_FL_F_EXCL) { 481 read_unlock_bh(&ip6_sk_fl_lock); 482 goto done; 483 } 484 fl1 = sfl->fl; 485 atomic_inc(&fl1->users); 486 break; 487 } 488 } 489 read_unlock_bh(&ip6_sk_fl_lock); 490 491 if (fl1 == NULL) 492 fl1 = fl_lookup(freq.flr_label); 493 if (fl1) { 494 err = -EEXIST; 495 if (freq.flr_flags&IPV6_FL_F_EXCL) 496 goto release; 497 err = -EPERM; 498 if (fl1->share == IPV6_FL_S_EXCL || 499 fl1->share != fl->share || 500 fl1->owner != fl->owner) 501 goto release; 502 503 err = -EINVAL; 504 if (!ipv6_addr_equal(&fl1->dst, &fl->dst) || 505 ipv6_opt_cmp(fl1->opt, fl->opt)) 506 goto release; 507 508 err = -ENOMEM; 509 if (sfl1 == NULL) 510 goto release; 511 if (fl->linger > fl1->linger) 512 fl1->linger = fl->linger; 513 if ((long)(fl->expires - fl1->expires) > 0) 514 fl1->expires = fl->expires; 515 write_lock_bh(&ip6_sk_fl_lock); 516 sfl1->fl = fl1; 517 sfl1->next = np->ipv6_fl_list; 518 np->ipv6_fl_list = sfl1; 519 write_unlock_bh(&ip6_sk_fl_lock); 520 fl_free(fl); 521 return 0; 522 523 release: 524 fl_release(fl1); 525 goto done; 526 } 527 } 528 err = -ENOENT; 529 if (!(freq.flr_flags&IPV6_FL_F_CREATE)) 530 goto done; 531 532 err = -ENOMEM; 533 if (sfl1 == NULL || (err = mem_check(sk)) != 0) 534 goto done; 535 536 err = fl_intern(fl, freq.flr_label); 537 if (err) 538 goto done; 539 540 if (!freq.flr_label) { 541 if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label, 542 &fl->label, sizeof(fl->label))) { 543 /* Intentionally ignore fault. */ 544 } 545 } 546 547 sfl1->fl = fl; 548 sfl1->next = np->ipv6_fl_list; 549 np->ipv6_fl_list = sfl1; 550 return 0; 551 552 default: 553 return -EINVAL; 554 } 555 556 done: 557 fl_free(fl); 558 kfree(sfl1); 559 return err; 560 } 561 562 #ifdef CONFIG_PROC_FS 563 564 struct ip6fl_iter_state { 565 int bucket; 566 }; 567 568 #define ip6fl_seq_private(seq) ((struct ip6fl_iter_state *)(seq)->private) 569 570 static struct ip6_flowlabel *ip6fl_get_first(struct seq_file *seq) 571 { 572 struct ip6_flowlabel *fl = NULL; 573 struct ip6fl_iter_state *state = ip6fl_seq_private(seq); 574 575 for (state->bucket = 0; state->bucket <= FL_HASH_MASK; ++state->bucket) { 576 if (fl_ht[state->bucket]) { 577 fl = fl_ht[state->bucket]; 578 break; 579 } 580 } 581 return fl; 582 } 583 584 static struct ip6_flowlabel *ip6fl_get_next(struct seq_file *seq, struct ip6_flowlabel *fl) 585 { 586 struct ip6fl_iter_state *state = ip6fl_seq_private(seq); 587 588 fl = fl->next; 589 while (!fl) { 590 if (++state->bucket <= FL_HASH_MASK) 591 fl = fl_ht[state->bucket]; 592 else 593 break; 594 } 595 return fl; 596 } 597 598 static struct ip6_flowlabel *ip6fl_get_idx(struct seq_file *seq, loff_t pos) 599 { 600 struct ip6_flowlabel *fl = ip6fl_get_first(seq); 601 if (fl) 602 while (pos && (fl = ip6fl_get_next(seq, fl)) != NULL) 603 --pos; 604 return pos ? NULL : fl; 605 } 606 607 static void *ip6fl_seq_start(struct seq_file *seq, loff_t *pos) 608 { 609 read_lock_bh(&ip6_fl_lock); 610 return *pos ? ip6fl_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; 611 } 612 613 static void *ip6fl_seq_next(struct seq_file *seq, void *v, loff_t *pos) 614 { 615 struct ip6_flowlabel *fl; 616 617 if (v == SEQ_START_TOKEN) 618 fl = ip6fl_get_first(seq); 619 else 620 fl = ip6fl_get_next(seq, v); 621 ++*pos; 622 return fl; 623 } 624 625 static void ip6fl_seq_stop(struct seq_file *seq, void *v) 626 { 627 read_unlock_bh(&ip6_fl_lock); 628 } 629 630 static int ip6fl_seq_show(struct seq_file *seq, void *v) 631 { 632 if (v == SEQ_START_TOKEN) 633 seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n", 634 "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt"); 635 else { 636 struct ip6_flowlabel *fl = v; 637 seq_printf(seq, 638 "%05X %-1d %-6d %-6d %-6ld %-8ld " NIP6_SEQFMT " %-4d\n", 639 (unsigned)ntohl(fl->label), 640 fl->share, 641 (unsigned)fl->owner, 642 atomic_read(&fl->users), 643 fl->linger/HZ, 644 (long)(fl->expires - jiffies)/HZ, 645 NIP6(fl->dst), 646 fl->opt ? fl->opt->opt_nflen : 0); 647 } 648 return 0; 649 } 650 651 static struct seq_operations ip6fl_seq_ops = { 652 .start = ip6fl_seq_start, 653 .next = ip6fl_seq_next, 654 .stop = ip6fl_seq_stop, 655 .show = ip6fl_seq_show, 656 }; 657 658 static int ip6fl_seq_open(struct inode *inode, struct file *file) 659 { 660 struct seq_file *seq; 661 int rc = -ENOMEM; 662 struct ip6fl_iter_state *s = kzalloc(sizeof(*s), GFP_KERNEL); 663 664 if (!s) 665 goto out; 666 667 rc = seq_open(file, &ip6fl_seq_ops); 668 if (rc) 669 goto out_kfree; 670 671 seq = file->private_data; 672 seq->private = s; 673 out: 674 return rc; 675 out_kfree: 676 kfree(s); 677 goto out; 678 } 679 680 static const struct file_operations ip6fl_seq_fops = { 681 .owner = THIS_MODULE, 682 .open = ip6fl_seq_open, 683 .read = seq_read, 684 .llseek = seq_lseek, 685 .release = seq_release_private, 686 }; 687 #endif 688 689 690 void ip6_flowlabel_init(void) 691 { 692 #ifdef CONFIG_PROC_FS 693 proc_net_fops_create("ip6_flowlabel", S_IRUGO, &ip6fl_seq_fops); 694 #endif 695 } 696 697 void ip6_flowlabel_cleanup(void) 698 { 699 del_timer(&ip6_fl_gc_timer); 700 #ifdef CONFIG_PROC_FS 701 proc_net_remove("ip6_flowlabel"); 702 #endif 703 } 704