bsd/net/pf_osfp.c

   1 /*
   2  * Copyright (c) 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*      $apfw: pf_osfp.c,v 1.4 2008/08/27 00:01:32 jhw Exp $ */
  30 /*      $OpenBSD: pf_osfp.c,v 1.12 2006/12/13 18:14:10 itojun Exp $ */
  31
  32 /*
  33  * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
  34  *
  35  * Permission to use, copy, modify, and distribute this software for any
  36  * purpose with or without fee is hereby granted, provided that the above
  37  * copyright notice and this permission notice appear in all copies.
  38  *
  39  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  40  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  41  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  42  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  43  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  44  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  45  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  46  *
  47  */
  48
  49 #include <machine/endian.h>
  50 #include <sys/param.h>
  51 #include <sys/socket.h>
  52 #include <sys/systm.h>
  53 #include <sys/mbuf.h>
  54
  55 #include <netinet/in.h>
  56 #include <netinet/in_systm.h>
  57 #include <netinet/ip.h>
  58 #include <netinet/tcp.h>
  59 #include <netinet/tcp_fsm.h>
  60
  61 #include <net/if.h>
  62 #include <net/pfvar.h>
  63
  64 #if INET6
  65 #include <netinet/ip6.h>
  66 #include <netinet6/in6_var.h>
  67 #endif /* INET6 */
  68
  69 #define DPFPRINTF(format, x...)                 \
  70         if (pf_status.debug >= PF_DEBUG_NOISY)  \
  71                 printf(format, ##x)
  72
  73 static SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
  74 static struct pool pf_osfp_entry_pl;
  75 static struct pool pf_osfp_pl;
  76
  77 static struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *,
  78     struct pf_os_fingerprint *, u_int8_t);
  79 static struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *,
  80     struct pf_os_fingerprint *);
  81 static void pf_osfp_insert(struct pf_osfp_list *, struct pf_os_fingerprint *);
  82
  83
  84 /*
  85  * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
  86  * Returns the list of possible OSes.
  87  */
  88 struct pf_osfp_enlist *
  89 pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
  90     const struct tcphdr *tcp)
  91 {
  92         struct ip *ip;
  93         struct ip6_hdr *ip6;
  94         char hdr[60];
  95
  96         if ((pd->af != PF_INET && pd->af != PF_INET6) ||
  97             pd->proto != IPPROTO_TCP ||
  98             (tcp->th_off << 2) < (int)sizeof (*tcp))
  99                 return (NULL);
 100
 101         if (pd->af == PF_INET) {
 102                 ip = mtod(m, struct ip *);
 103                 ip6 = (struct ip6_hdr *)NULL;
 104         } else {
 105                 ip = (struct ip *)NULL;
 106                 ip6 = mtod(m, struct ip6_hdr *);
 107         }
 108         if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
 109             pd->af))
 110                 return (NULL);
 111
 112         return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
 113 }
 114
 115 struct pf_osfp_enlist *
 116 pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6,
 117     const struct tcphdr *tcp)
 118 {
 119 #if !INET6
 120 #pragma unused(ip6)
 121 #endif /* !INET6 */
 122         struct pf_os_fingerprint fp, *fpresult;
 123         int cnt, optlen = 0;
 124         const u_int8_t *optp;
 125         char srcname[128];
 126
 127         if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
 128                 return (NULL);
 129         if (ip) {
 130                 if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
 131                         return (NULL);
 132         }
 133
 134         memset(&fp, 0, sizeof (fp));
 135
 136         if (ip) {
 137                 fp.fp_psize = ntohs(ip->ip_len);
 138                 fp.fp_ttl = ip->ip_ttl;
 139                 if (ip->ip_off & htons(IP_DF))
 140                         fp.fp_flags |= PF_OSFP_DF;
 141                 (void) inet_ntop(AF_INET, &ip->ip_src, srcname,
 142                     (socklen_t)sizeof (srcname));
 143         }
 144 #if INET6
 145         else if (ip6) {
 146                 /* jumbo payload? */
 147                 fp.fp_psize = sizeof (struct ip6_hdr) + ntohs(ip6->ip6_plen);
 148                 fp.fp_ttl = ip6->ip6_hlim;
 149                 fp.fp_flags |= PF_OSFP_DF;
 150                 fp.fp_flags |= PF_OSFP_INET6;
 151                 (void) inet_ntop(AF_INET6, &ip6->ip6_src, srcname,
 152                     (socklen_t)sizeof (srcname));
 153         }
 154 #endif
 155         else
 156                 return (NULL);
 157         fp.fp_wsize = ntohs(tcp->th_win);
 158
 159
 160         cnt = (tcp->th_off << 2) - sizeof (*tcp);
 161         optp = (const u_int8_t *)((const char *)tcp + sizeof (*tcp));
 162         for (; cnt > 0; cnt -= optlen, optp += optlen) {
 163                 if (*optp == TCPOPT_EOL)
 164                         break;
 165
 166                 fp.fp_optcnt++;
 167                 if (*optp == TCPOPT_NOP) {
 168                         fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
 169                             PF_OSFP_TCPOPT_NOP;
 170                         optlen = 1;
 171                 } else {
 172                         if (cnt < 2)
 173                                 return (NULL);
 174                         optlen = optp[1];
 175                         if (optlen > cnt || optlen < 2)
 176                                 return (NULL);
 177                         switch (*optp) {
 178                         case TCPOPT_MAXSEG:
 179                                 if (optlen >= TCPOLEN_MAXSEG)
 180                                         memcpy(&fp.fp_mss, &optp[2],
 181                                             sizeof (fp.fp_mss));
 182                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 183                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
 184 #if BYTE_ORDER != BIG_ENDIAN
 185                                 NTOHS(fp.fp_mss);
 186 #endif
 187                                 break;
 188                         case TCPOPT_WINDOW:
 189                                 if (optlen >= TCPOLEN_WINDOW)
 190                                         memcpy(&fp.fp_wscale, &optp[2],
 191                                             sizeof (fp.fp_wscale));
 192 #if BYTE_ORDER != BIG_ENDIAN
 193                                 NTOHS(fp.fp_wscale);
 194 #endif
 195                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 196                                     PF_OSFP_TCPOPT_BITS) |
 197                                     PF_OSFP_TCPOPT_WSCALE;
 198                                 break;
 199                         case TCPOPT_SACK_PERMITTED:
 200                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 201                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
 202                                 break;
 203                         case TCPOPT_TIMESTAMP:
 204                                 if (optlen >= TCPOLEN_TIMESTAMP) {
 205                                         u_int32_t ts;
 206                                         memcpy(&ts, &optp[2], sizeof (ts));
 207                                         if (ts == 0)
 208                                                 fp.fp_flags |= PF_OSFP_TS0;
 209
 210                                 }
 211                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 212                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
 213                                 break;
 214                         default:
 215                                 return (NULL);
 216                         }
 217                 }
 218                 optlen = MAX(optlen, 1);        /* paranoia */
 219         }
 220
 221         DPFPRINTF("fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
 222             "(TS=%s,M=%s%d,W=%s%d)\n",
 223             srcname, ntohs(tcp->th_sport),
 224             fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
 225             fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
 226             (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
 227             (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 228             (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 229             fp.fp_mss,
 230             (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 231             (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 232             fp.fp_wscale);
 233
 234         if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
 235             PF_OSFP_MAXTTL_OFFSET)))
 236                 return (&fpresult->fp_oses);
 237         return (NULL);
 238 }
 239
 240 /* Match a fingerprint ID against a list of OSes */
 241 int
 242 pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
 243 {
 244         struct pf_osfp_entry *entry;
 245         int os_class, os_version, os_subtype;
 246         int en_class, en_version, en_subtype;
 247
 248         if (os == PF_OSFP_ANY)
 249                 return (1);
 250         if (list == NULL) {
 251                 DPFPRINTF("osfp no match against %x\n", os);
 252                 return (os == PF_OSFP_UNKNOWN);
 253         }
 254         PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
 255         SLIST_FOREACH(entry, list, fp_entry) {
 256                 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
 257                 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
 258                     (os_version == PF_OSFP_ANY || en_version == os_version) &&
 259                     (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
 260                         DPFPRINTF("osfp matched %s %s %s  %x==%x\n",
 261                             entry->fp_class_nm, entry->fp_version_nm,
 262                             entry->fp_subtype_nm, os, entry->fp_os);
 263                         return (1);
 264                 }
 265         }
 266         DPFPRINTF("fingerprint 0x%x didn't match\n", os);
 267         return (0);
 268 }
 269
 270 /* Initialize the OS fingerprint system */
 271 void
 272 pf_osfp_initialize(void)
 273 {
 274         pool_init(&pf_osfp_entry_pl, sizeof (struct pf_osfp_entry), 0, 0, 0,
 275             "pfosfpen", NULL);
 276         pool_init(&pf_osfp_pl, sizeof (struct pf_os_fingerprint), 0, 0, 0,
 277             "pfosfp", NULL);
 278         SLIST_INIT(&pf_osfp_list);
 279 }
 280
 281 #if 0
 282 void
 283 pf_osfp_destroy(void)
 284 {
 285         pf_osfp_flush();
 286
 287         pool_destroy(&pf_osfp_pl);
 288         pool_destroy(&pf_osfp_entry_pl);
 289 }
 290 #endif
 291
 292 /* Flush the fingerprint list */
 293 void
 294 pf_osfp_flush(void)
 295 {
 296         struct pf_os_fingerprint *fp;
 297         struct pf_osfp_entry *entry;
 298
 299         while ((fp = SLIST_FIRST(&pf_osfp_list))) {
 300                 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
 301                 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
 302                         SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
 303                         pool_put(&pf_osfp_entry_pl, entry);
 304                 }
 305                 pool_put(&pf_osfp_pl, fp);
 306         }
 307 }
 308
 309
 310 /* Add a fingerprint */
 311 int
 312 pf_osfp_add(struct pf_osfp_ioctl *fpioc)
 313 {
 314         struct pf_os_fingerprint *fp, fpadd;
 315         struct pf_osfp_entry *entry;
 316
 317         memset(&fpadd, 0, sizeof (fpadd));
 318         fpadd.fp_tcpopts = fpioc->fp_tcpopts;
 319         fpadd.fp_wsize = fpioc->fp_wsize;
 320         fpadd.fp_psize = fpioc->fp_psize;
 321         fpadd.fp_mss = fpioc->fp_mss;
 322         fpadd.fp_flags = fpioc->fp_flags;
 323         fpadd.fp_optcnt = fpioc->fp_optcnt;
 324         fpadd.fp_wscale = fpioc->fp_wscale;
 325         fpadd.fp_ttl = fpioc->fp_ttl;
 326
 327         DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
 328             "(TS=%s,M=%s%d,W=%s%d) %x\n",
 329             fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
 330             fpioc->fp_os.fp_subtype_nm,
 331             (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
 332             (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
 333             (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
 334             (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
 335             fpadd.fp_wsize,
 336             fpadd.fp_ttl,
 337             (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
 338             (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
 339             (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
 340             fpadd.fp_psize,
 341             (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
 342             (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
 343             (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 344             (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 345             fpadd.fp_mss,
 346             (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 347             (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 348             fpadd.fp_wscale,
 349             fpioc->fp_os.fp_os);
 350
 351
 352         if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
 353                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 354                         if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
 355                                 return (EEXIST);
 356                 }
 357                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_WAITOK)) == NULL)
 358                         return (ENOMEM);
 359         } else {
 360                 if ((fp = pool_get(&pf_osfp_pl, PR_WAITOK)) == NULL)
 361                         return (ENOMEM);
 362                 memset(fp, 0, sizeof (*fp));
 363                 fp->fp_tcpopts = fpioc->fp_tcpopts;
 364                 fp->fp_wsize = fpioc->fp_wsize;
 365                 fp->fp_psize = fpioc->fp_psize;
 366                 fp->fp_mss = fpioc->fp_mss;
 367                 fp->fp_flags = fpioc->fp_flags;
 368                 fp->fp_optcnt = fpioc->fp_optcnt;
 369                 fp->fp_wscale = fpioc->fp_wscale;
 370                 fp->fp_ttl = fpioc->fp_ttl;
 371                 SLIST_INIT(&fp->fp_oses);
 372                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_WAITOK)) == NULL) {
 373                         pool_put(&pf_osfp_pl, fp);
 374                         return (ENOMEM);
 375                 }
 376                 pf_osfp_insert(&pf_osfp_list, fp);
 377         }
 378         memcpy(entry, &fpioc->fp_os, sizeof (*entry));
 379
 380         /* Make sure the strings are NUL terminated */
 381         entry->fp_class_nm[sizeof (entry->fp_class_nm)-1] = '\0';
 382         entry->fp_version_nm[sizeof (entry->fp_version_nm)-1] = '\0';
 383         entry->fp_subtype_nm[sizeof (entry->fp_subtype_nm)-1] = '\0';
 384
 385         SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
 386
 387 #ifdef PFDEBUG
 388         if ((fp = pf_osfp_validate()))
 389                 printf("Invalid fingerprint list\n");
 390 #endif /* PFDEBUG */
 391         return (0);
 392 }
 393
 394
 395 /* Find a fingerprint in the list */
 396 struct pf_os_fingerprint *
 397 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
 398     u_int8_t ttldiff)
 399 {
 400         struct pf_os_fingerprint *f;
 401
 402 #define MATCH_INT(_MOD, _DC, _field)                                    \
 403         if ((f->fp_flags & _DC) == 0) {                                 \
 404                 if ((f->fp_flags & _MOD) == 0) {                        \
 405                         if (f->_field != find->_field)                  \
 406                                 continue;                               \
 407                 } else {                                                \
 408                         if (f->_field == 0 || find->_field % f->_field) \
 409                                 continue;                               \
 410                 }                                                       \
 411         }
 412
 413         SLIST_FOREACH(f, list, fp_next) {
 414                 if (f->fp_tcpopts != find->fp_tcpopts ||
 415                     f->fp_optcnt != find->fp_optcnt ||
 416                     f->fp_ttl < find->fp_ttl ||
 417                     f->fp_ttl - find->fp_ttl > ttldiff ||
 418                     (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
 419                     (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
 420                         continue;
 421
 422                 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
 423                 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
 424                 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
 425                 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
 426                         if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 427                                 if (find->fp_mss == 0)
 428                                         continue;
 429
 430 /*
 431  * Some "smart" NAT devices and DSL routers will tweak the MSS size and
 432  * will set it to whatever is suitable for the link type.
 433  */
 434 #define SMART_MSS       1460
 435                                 if ((find->fp_wsize % find->fp_mss ||
 436                                     find->fp_wsize / find->fp_mss !=
 437                                     f->fp_wsize) &&
 438                                     (find->fp_wsize % SMART_MSS ||
 439                                     find->fp_wsize / SMART_MSS !=
 440                                     f->fp_wsize))
 441                                         continue;
 442                         } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 443                                 if (find->fp_mss == 0)
 444                                         continue;
 445
 446 #define MTUOFF  (sizeof (struct ip) + sizeof (struct tcphdr))
 447 #define SMART_MTU       (SMART_MSS + MTUOFF)
 448                                 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
 449                                     find->fp_wsize / (find->fp_mss + MTUOFF) !=
 450                                     f->fp_wsize) &&
 451                                     (find->fp_wsize % SMART_MTU ||
 452                                     find->fp_wsize / SMART_MTU !=
 453                                     f->fp_wsize))
 454                                         continue;
 455                         } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 456                                 if (f->fp_wsize == 0 || find->fp_wsize %
 457                                     f->fp_wsize)
 458                                         continue;
 459                         } else {
 460                                 if (f->fp_wsize != find->fp_wsize)
 461                                         continue;
 462                         }
 463                 }
 464                 return (f);
 465         }
 466
 467         return (NULL);
 468 }
 469
 470 /* Find an exact fingerprint in the list */
 471 struct pf_os_fingerprint *
 472 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
 473 {
 474         struct pf_os_fingerprint *f;
 475
 476         SLIST_FOREACH(f, list, fp_next) {
 477                 if (f->fp_tcpopts == find->fp_tcpopts &&
 478                     f->fp_wsize == find->fp_wsize &&
 479                     f->fp_psize == find->fp_psize &&
 480                     f->fp_mss == find->fp_mss &&
 481                     f->fp_flags == find->fp_flags &&
 482                     f->fp_optcnt == find->fp_optcnt &&
 483                     f->fp_wscale == find->fp_wscale &&
 484                     f->fp_ttl == find->fp_ttl)
 485                         return (f);
 486         }
 487
 488         return (NULL);
 489 }
 490
 491 /* Insert a fingerprint into the list */
 492 void
 493 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
 494 {
 495         struct pf_os_fingerprint *f, *prev = NULL;
 496
 497         /* XXX need to go semi tree based.  can key on tcp options */
 498
 499         SLIST_FOREACH(f, list, fp_next)
 500                 prev = f;
 501         if (prev)
 502                 SLIST_INSERT_AFTER(prev, ins, fp_next);
 503         else
 504                 SLIST_INSERT_HEAD(list, ins, fp_next);
 505 }
 506
 507 /* Fill a fingerprint by its number (from an ioctl) */
 508 int
 509 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
 510 {
 511         struct pf_os_fingerprint *fp;
 512         struct pf_osfp_entry *entry;
 513         int num = fpioc->fp_getnum;
 514         int i = 0;
 515
 516
 517         memset(fpioc, 0, sizeof (*fpioc));
 518         SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
 519                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 520                         if (i++ == num) {
 521                                 fpioc->fp_mss = fp->fp_mss;
 522                                 fpioc->fp_wsize = fp->fp_wsize;
 523                                 fpioc->fp_flags = fp->fp_flags;
 524                                 fpioc->fp_psize = fp->fp_psize;
 525                                 fpioc->fp_ttl = fp->fp_ttl;
 526                                 fpioc->fp_wscale = fp->fp_wscale;
 527                                 fpioc->fp_getnum = num;
 528                                 memcpy(&fpioc->fp_os, entry,
 529                                     sizeof (fpioc->fp_os));
 530                                 return (0);
 531                         }
 532                 }
 533         }
 534
 535         return (EBUSY);
 536 }
 537
 538
 539 /* Validate that each signature is reachable */
 540 struct pf_os_fingerprint *
 541 pf_osfp_validate(void)
 542 {
 543         struct pf_os_fingerprint *f, *f2, find;
 544
 545         SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
 546                 memcpy(&find, f, sizeof (find));
 547
 548                 /* We do a few MSS/th_win percolations to make things unique */
 549                 if (find.fp_mss == 0)
 550                         find.fp_mss = 128;
 551                 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
 552                         find.fp_wsize *= find.fp_mss, 1;
 553                 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
 554                         find.fp_wsize *= (find.fp_mss + 40);
 555                 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
 556                         find.fp_wsize *= 2;
 557                 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
 558                         if (f2)
 559                                 printf("Found \"%s %s %s\" instead of "
 560                                     "\"%s %s %s\"\n",
 561                                     SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
 562                                     SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
 563                                     SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
 564                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 565                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 566                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 567                         else
 568                                 printf("Couldn't find \"%s %s %s\"\n",
 569                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 570                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 571                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 572                         return (f);
 573                 }
 574         }
 575         return (NULL);
 576 }