sys/net/pf/pf_osfp.c

   1 /*      $FreeBSD: src/sys/contrib/pf/net/pf_osfp.c,v 1.4 2004/06/16 23:24:00 mlaier Exp $       */
   2 /*      $OpenBSD: pf_osfp.c,v 1.9 2004/01/04 20:08:42 pvalchev Exp $ */
   3 /*      $DragonFly: src/sys/net/pf/pf_osfp.c,v 1.2 2006/12/22 23:44:57 swildner Exp $ */
   4
   5 /*
   6  * Copyright (c) 2004 The DragonFly Project.  All rights reserved.
   7  *
   8  * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
   9  *
  10  * Permission to use, copy, modify, and distribute this software for any
  11  * purpose with or without fee is hereby granted, provided that the above
  12  * copyright notice and this permission notice appear in all copies.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  15  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  16  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  17  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  18  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  19  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  20  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  21  *
  22  */
  23
  24 #include <sys/param.h>
  25 #include <sys/socket.h>
  26 #ifdef _KERNEL
  27 # include <sys/systm.h>
  28 # include <vm/vm_zone.h>
  29 #endif /* _KERNEL */
  30 #include <sys/mbuf.h>
  31
  32 #include <netinet/in.h>
  33 #include <netinet/in_systm.h>
  34 #include <netinet/ip.h>
  35 #include <netinet/tcp.h>
  36
  37 #include <net/if.h>
  38 #include <net/pf/pfvar.h>
  39
  40 #ifdef INET6
  41 #include <netinet/ip6.h>
  42 #endif /* INET6 */
  43
  44
  45 #ifdef _KERNEL
  46 # define DPFPRINTF(format, x...)                \
  47         if (pf_status.debug >= PF_DEBUG_NOISY)  \
  48                 kprintf(format , ##x)
  49 typedef vm_zone_t pool_t;
  50
  51 #else
  52 /* Userland equivalents so we can lend code to tcpdump et al. */
  53
  54 # include <arpa/inet.h>
  55 # include <errno.h>
  56 # include <stdio.h>
  57 # include <stdlib.h>
  58 # include <string.h>
  59 # define pool_t                 int
  60 # define pool_get(pool, flags)  malloc(*(pool))
  61 # define pool_put(pool, item)   free(item)
  62 # define pool_init(pool, size, a, ao, f, m, p)  (*(pool)) = (size)
  63
  64 # ifdef PFDEBUG
  65 #  include <sys/stdarg.h>
  66 #  define DPFPRINTF(format, x...)       fprintf(stderr, format , ##x)
  67 # else
  68 #  define DPFPRINTF(format, x...)       ((void)0)
  69 # endif /* PFDEBUG */
  70 #endif /* _KERNEL */
  71
  72
  73 SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
  74 pool_t pf_osfp_entry_pl;
  75 pool_t pf_osfp_pl;
  76
  77 struct pf_os_fingerprint        *pf_osfp_find(struct pf_osfp_list *,
  78                                     struct pf_os_fingerprint *, u_int8_t);
  79 struct pf_os_fingerprint        *pf_osfp_find_exact(struct pf_osfp_list *,
  80                                     struct pf_os_fingerprint *);
  81 void                             pf_osfp_insert(struct pf_osfp_list *,
  82                                     struct pf_os_fingerprint *);
  83
  84
  85 #ifdef _KERNEL
  86 /*
  87  * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
  88  * Returns the list of possible OSes.
  89  */
  90 struct pf_osfp_enlist *
  91 pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
  92     const struct tcphdr *tcp)
  93 {
  94         struct ip *ip;
  95         char hdr[60];
  96
  97         /* XXX don't have a fingerprint database for IPv6 :-( */
  98         if (pd->af != PF_INET || pd->proto != IPPROTO_TCP || (tcp->th_off << 2)
  99             < sizeof(*tcp))
 100                 return (NULL);
 101
 102         ip = mtod(m, struct ip *);
 103         if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL, pd->af))
 104                 return (NULL);
 105
 106         return (pf_osfp_fingerprint_hdr(ip, (struct tcphdr *)hdr));
 107 }
 108 #endif /* _KERNEL */
 109
 110 struct pf_osfp_enlist *
 111 pf_osfp_fingerprint_hdr(const struct ip *ip, const struct tcphdr *tcp)
 112 {
 113         struct pf_os_fingerprint fp, *fpresult;
 114         int cnt, optlen = 0;
 115         const u_int8_t *optp;
 116
 117         if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN || (ip->ip_off &
 118             IP_OFFMASK))
 119                 return (NULL);
 120
 121         memset(&fp, 0, sizeof(fp));
 122
 123         fp.fp_psize = ip->ip_len;
 124         fp.fp_ttl = ip->ip_ttl;
 125         if (ip->ip_off & IP_DF)
 126                 fp.fp_flags |= PF_OSFP_DF;
 127         fp.fp_wsize = ntohs(tcp->th_win);
 128
 129
 130         cnt = (tcp->th_off << 2) - sizeof(*tcp);
 131         optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
 132         for (; cnt > 0; cnt -= optlen, optp += optlen) {
 133                 if (*optp == TCPOPT_EOL)
 134                         break;
 135
 136                 fp.fp_optcnt++;
 137                 if (*optp == TCPOPT_NOP) {
 138                         fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
 139                             PF_OSFP_TCPOPT_NOP;
 140                         optlen = 1;
 141                 } else {
 142                         if (cnt < 2)
 143                                 return (NULL);
 144                         optlen = optp[1];
 145                         if (optlen > cnt || optlen < 2)
 146                                 return (NULL);
 147                         switch (*optp) {
 148                         case TCPOPT_MAXSEG:
 149                                 if (optlen >= TCPOLEN_MAXSEG)
 150                                         memcpy(&fp.fp_mss, &optp[2],
 151                                             sizeof(fp.fp_mss));
 152                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 153                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
 154                                 fp.fp_mss = ntohs(fp.fp_mss);
 155                                 break;
 156                         case TCPOPT_WINDOW:
 157                                 if (optlen >= TCPOLEN_WINDOW)
 158                                         memcpy(&fp.fp_wscale, &optp[2],
 159                                             sizeof(fp.fp_wscale));
 160                                 fp.fp_wscale = ntohs(fp.fp_wscale);
 161                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 162                                     PF_OSFP_TCPOPT_BITS) |
 163                                     PF_OSFP_TCPOPT_WSCALE;
 164                                 break;
 165                         case TCPOPT_SACK_PERMITTED:
 166                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 167                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
 168                                 break;
 169                         case TCPOPT_TIMESTAMP:
 170                                 if (optlen >= TCPOLEN_TIMESTAMP) {
 171                                         u_int32_t ts;
 172                                         memcpy(&ts, &optp[2], sizeof(ts));
 173                                         if (ts == 0)
 174                                                 fp.fp_flags |= PF_OSFP_TS0;
 175
 176                                 }
 177                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 178                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
 179                                 break;
 180                         default:
 181                                 return (NULL);
 182                         }
 183                 }
 184                 optlen = MAX(optlen, 1);        /* paranoia */
 185         }
 186
 187         DPFPRINTF("fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
 188             "(TS=%s,M=%s%d,W=%s%d)\n",
 189             inet_ntoa(ip->ip_src), ntohs(tcp->th_sport),
 190             fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
 191             fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
 192             (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
 193             (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 194             (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 195             fp.fp_mss,
 196             (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 197             (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 198             fp.fp_wscale);
 199
 200         if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
 201             PF_OSFP_MAXTTL_OFFSET)))
 202                 return (&fpresult->fp_oses);
 203         return (NULL);
 204 }
 205
 206 /* Match a fingerprint ID against a list of OSes */
 207 int
 208 pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
 209 {
 210         struct pf_osfp_entry *entry;
 211         int os_class, os_version, os_subtype;
 212         int en_class, en_version, en_subtype;
 213
 214         if (os == PF_OSFP_ANY)
 215                 return (1);
 216         if (list == NULL) {
 217                 DPFPRINTF("osfp no match against %x\n", os);
 218                 return (os == PF_OSFP_UNKNOWN);
 219         }
 220         PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
 221         SLIST_FOREACH(entry, list, fp_entry) {
 222                 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
 223                 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
 224                     (os_version == PF_OSFP_ANY || en_version == os_version) &&
 225                     (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
 226                         DPFPRINTF("osfp matched %s %s %s  %x==%x\n",
 227                             entry->fp_class_nm, entry->fp_version_nm,
 228                             entry->fp_subtype_nm, os, entry->fp_os);
 229                         return (1);
 230                 }
 231         }
 232         DPFPRINTF("fingerprint 0x%x didn't match\n", os);
 233         return (0);
 234 }
 235
 236 /* Initialize the OS fingerprint system */
 237 int
 238 pf_osfp_initialize(void)
 239 {
 240         int error = 0;
 241
 242 #ifdef _KERNEL
 243         do {
 244                 error = ENOMEM;
 245                 pf_osfp_entry_pl = pf_osfp_pl = NULL;
 246                 ZONE_CREATE(pf_osfp_entry_pl, struct pf_osfp_entry, "pfospfen");
 247                 ZONE_CREATE(pf_osfp_pl, struct pf_os_fingerprint, "pfosfp");
 248                 error = 0;
 249         } while(0);
 250 #else
 251         pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
 252             "pfosfpen", NULL);
 253         pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
 254             "pfosfp", NULL);
 255 #endif
 256         SLIST_INIT(&pf_osfp_list);
 257
 258         return (error);
 259 }
 260
 261 #ifdef _KERNEL
 262 void
 263 pf_osfp_cleanup(void)
 264 {
 265         ZONE_DESTROY(pf_osfp_entry_pl);
 266         ZONE_DESTROY(pf_osfp_pl);
 267 }
 268 #endif
 269
 270 /* Flush the fingerprint list */
 271 void
 272 pf_osfp_flush(void)
 273 {
 274         struct pf_os_fingerprint *fp;
 275         struct pf_osfp_entry *entry;
 276
 277         while ((fp = SLIST_FIRST(&pf_osfp_list))) {
 278                 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
 279                 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
 280                         SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
 281                         pool_put(&pf_osfp_entry_pl, entry);
 282                 }
 283                 pool_put(&pf_osfp_pl, fp);
 284         }
 285 }
 286
 287
 288 /* Add a fingerprint */
 289 int
 290 pf_osfp_add(struct pf_osfp_ioctl *fpioc)
 291 {
 292         struct pf_os_fingerprint *fp, fpadd;
 293         struct pf_osfp_entry *entry;
 294
 295         memset(&fpadd, 0, sizeof(fpadd));
 296         fpadd.fp_tcpopts = fpioc->fp_tcpopts;
 297         fpadd.fp_wsize = fpioc->fp_wsize;
 298         fpadd.fp_psize = fpioc->fp_psize;
 299         fpadd.fp_mss = fpioc->fp_mss;
 300         fpadd.fp_flags = fpioc->fp_flags;
 301         fpadd.fp_optcnt = fpioc->fp_optcnt;
 302         fpadd.fp_wscale = fpioc->fp_wscale;
 303         fpadd.fp_ttl = fpioc->fp_ttl;
 304
 305         DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
 306             "(TS=%s,M=%s%d,W=%s%d) %x\n",
 307             fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
 308             fpioc->fp_os.fp_subtype_nm,
 309             (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
 310             (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
 311             (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
 312             (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
 313             fpadd.fp_wsize,
 314             fpadd.fp_ttl,
 315             (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
 316             (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
 317             (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
 318             fpadd.fp_psize,
 319             (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
 320             (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
 321             (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 322             (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 323             fpadd.fp_mss,
 324             (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 325             (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 326             fpadd.fp_wscale,
 327             fpioc->fp_os.fp_os);
 328
 329
 330         if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
 331                  SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 332                         if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
 333                                 return (EEXIST);
 334                 }
 335                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL)
 336                         return (ENOMEM);
 337         } else {
 338                 if ((fp = pool_get(&pf_osfp_pl, PR_NOWAIT)) == NULL)
 339                         return (ENOMEM);
 340                 memset(fp, 0, sizeof(*fp));
 341                 fp->fp_tcpopts = fpioc->fp_tcpopts;
 342                 fp->fp_wsize = fpioc->fp_wsize;
 343                 fp->fp_psize = fpioc->fp_psize;
 344                 fp->fp_mss = fpioc->fp_mss;
 345                 fp->fp_flags = fpioc->fp_flags;
 346                 fp->fp_optcnt = fpioc->fp_optcnt;
 347                 fp->fp_wscale = fpioc->fp_wscale;
 348                 fp->fp_ttl = fpioc->fp_ttl;
 349                 SLIST_INIT(&fp->fp_oses);
 350                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL) {
 351                         pool_put(&pf_osfp_pl, fp);
 352                         return (ENOMEM);
 353                 }
 354                 pf_osfp_insert(&pf_osfp_list, fp);
 355         }
 356         memcpy(entry, &fpioc->fp_os, sizeof(*entry));
 357
 358         /* Make sure the strings are NUL terminated */
 359         entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
 360         entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
 361         entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
 362
 363         SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
 364
 365 #ifdef PFDEBUG
 366         if ((fp = pf_osfp_validate()))
 367                 kprintf("Invalid fingerprint list\n");
 368 #endif /* PFDEBUG */
 369         return (0);
 370 }
 371
 372
 373 /* Find a fingerprint in the list */
 374 struct pf_os_fingerprint *
 375 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
 376     u_int8_t ttldiff)
 377 {
 378         struct pf_os_fingerprint *f;
 379
 380 #define MATCH_INT(_MOD, _DC, _field)                                    \
 381         if ((f->fp_flags & _DC) == 0) {                                 \
 382                 if ((f->fp_flags & _MOD) == 0) {                        \
 383                         if (f->_field != find->_field)                  \
 384                                 continue;                               \
 385                 } else {                                                \
 386                         if (f->_field == 0 || find->_field % f->_field) \
 387                                 continue;                               \
 388                 }                                                       \
 389         }
 390
 391         SLIST_FOREACH(f, list, fp_next) {
 392                 if (f->fp_tcpopts != find->fp_tcpopts ||
 393                     f->fp_optcnt != find->fp_optcnt ||
 394                     f->fp_ttl < find->fp_ttl ||
 395                     f->fp_ttl - find->fp_ttl > ttldiff ||
 396                     (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
 397                     (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
 398                         continue;
 399
 400                 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
 401                 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
 402                 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
 403                 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
 404                         if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 405                                 if (find->fp_mss == 0)
 406                                         continue;
 407
 408 /* Some "smart" NAT devices and DSL routers will tweak the MSS size and
 409  * will set it to whatever is suitable for the link type.
 410  */
 411 #define SMART_MSS       1460
 412                                 if ((find->fp_wsize % find->fp_mss ||
 413                                     find->fp_wsize / find->fp_mss !=
 414                                     f->fp_wsize) &&
 415                                     (find->fp_wsize % SMART_MSS ||
 416                                     find->fp_wsize / SMART_MSS !=
 417                                     f->fp_wsize))
 418                                         continue;
 419                         } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 420                                 if (find->fp_mss == 0)
 421                                         continue;
 422
 423 #define MTUOFF  (sizeof(struct ip) + sizeof(struct tcphdr))
 424 #define SMART_MTU       (SMART_MSS + MTUOFF)
 425                                 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
 426                                     find->fp_wsize / (find->fp_mss + MTUOFF) !=
 427                                     f->fp_wsize) &&
 428                                     (find->fp_wsize % SMART_MTU ||
 429                                     find->fp_wsize / SMART_MTU !=
 430                                     f->fp_wsize))
 431                                         continue;
 432                         } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 433                                 if (f->fp_wsize == 0 || find->fp_wsize %
 434                                     f->fp_wsize)
 435                                         continue;
 436                         } else {
 437                                 if (f->fp_wsize != find->fp_wsize)
 438                                         continue;
 439                         }
 440                 }
 441                 return (f);
 442         }
 443
 444         return (NULL);
 445 }
 446
 447 /* Find an exact fingerprint in the list */
 448 struct pf_os_fingerprint *
 449 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
 450 {
 451         struct pf_os_fingerprint *f;
 452
 453         SLIST_FOREACH(f, list, fp_next) {
 454                 if (f->fp_tcpopts == find->fp_tcpopts &&
 455                     f->fp_wsize == find->fp_wsize &&
 456                     f->fp_psize == find->fp_psize &&
 457                     f->fp_mss == find->fp_mss &&
 458                     f->fp_flags == find->fp_flags &&
 459                     f->fp_optcnt == find->fp_optcnt &&
 460                     f->fp_wscale == find->fp_wscale &&
 461                     f->fp_ttl == find->fp_ttl)
 462                         return (f);
 463         }
 464
 465         return (NULL);
 466 }
 467
 468 /* Insert a fingerprint into the list */
 469 void
 470 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
 471 {
 472         struct pf_os_fingerprint *f, *prev = NULL;
 473
 474         /* XXX need to go semi tree based.  can key on tcp options */
 475
 476         SLIST_FOREACH(f, list, fp_next)
 477                 prev = f;
 478         if (prev)
 479                 SLIST_INSERT_AFTER(prev, ins, fp_next);
 480         else
 481                 SLIST_INSERT_HEAD(list, ins, fp_next);
 482 }
 483
 484 /* Fill a fingerprint by its number (from an ioctl) */
 485 int
 486 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
 487 {
 488         struct pf_os_fingerprint *fp;
 489         struct pf_osfp_entry *entry;
 490         int num = fpioc->fp_getnum;
 491         int i = 0;
 492
 493
 494         memset(fpioc, 0, sizeof(*fpioc));
 495         SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
 496                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 497                         if (i++ == num) {
 498                                 fpioc->fp_mss = fp->fp_mss;
 499                                 fpioc->fp_wsize = fp->fp_wsize;
 500                                 fpioc->fp_flags = fp->fp_flags;
 501                                 fpioc->fp_psize = fp->fp_psize;
 502                                 fpioc->fp_ttl = fp->fp_ttl;
 503                                 fpioc->fp_wscale = fp->fp_wscale;
 504                                 fpioc->fp_getnum = num;
 505                                 memcpy(&fpioc->fp_os, entry,
 506                                     sizeof(fpioc->fp_os));
 507                                 return (0);
 508                         }
 509                 }
 510         }
 511
 512         return (EBUSY);
 513 }
 514
 515
 516 /* Validate that each signature is reachable */
 517 struct pf_os_fingerprint *
 518 pf_osfp_validate(void)
 519 {
 520         struct pf_os_fingerprint *f, *f2, find;
 521
 522         SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
 523                 memcpy(&find, f, sizeof(find));
 524
 525                 /* We do a few MSS/th_win percolations to make things unique */
 526                 if (find.fp_mss == 0)
 527                         find.fp_mss = 128;
 528                 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
 529                         find.fp_wsize *= find.fp_mss, 1;
 530                 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
 531                         find.fp_wsize *= (find.fp_mss + 40);
 532                 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
 533                         find.fp_wsize *= 2;
 534                 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
 535                         if (f2)
 536                                 kprintf("Found \"%s %s %s\" instead of "
 537                                     "\"%s %s %s\"\n",
 538                                     SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
 539                                     SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
 540                                     SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
 541                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 542                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 543                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 544                         else
 545                                 kprintf("Couldn't find \"%s %s %s\"\n",
 546                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 547                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 548                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 549                         return (f);
 550                 }
 551         }
 552         return (NULL);
 553 }