bsd/net/pf_osfp.c

   1 /*
   2  * Copyright (c) 2007-2020 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 #include <netinet/ip6.h>
  65 #include <netinet6/in6_var.h>
  66
  67 #define DPFPRINTF(format, x...)                 \
  68         if (pf_status.debug >= PF_DEBUG_NOISY)  \
  69                 printf(format, ##x)
  70
  71 static SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
  72 static struct pool pf_osfp_entry_pl;
  73 static struct pool pf_osfp_pl;
  74
  75 static struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *,
  76     struct pf_os_fingerprint *, u_int8_t);
  77 static struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *,
  78     struct pf_os_fingerprint *);
  79 static void pf_osfp_insert(struct pf_osfp_list *, struct pf_os_fingerprint *);
  80
  81
  82 /*
  83  * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
  84  * Returns the list of possible OSes.
  85  */
  86 struct pf_osfp_enlist *
  87 pf_osfp_fingerprint(struct pf_pdesc *pd, pbuf_t *pbuf, int off,
  88     const struct tcphdr *tcp)
  89 {
  90         struct ip *ip;
  91         struct ip6_hdr *ip6;
  92         char hdr[60];
  93
  94         if ((pd->af != PF_INET && pd->af != PF_INET6) ||
  95             pd->proto != IPPROTO_TCP ||
  96             (tcp->th_off << 2) < (int)sizeof(*tcp)) {
  97                 return NULL;
  98         }
  99
 100         if (pd->af == PF_INET) {
 101                 ip = pbuf->pb_data;
 102                 ip6 = (struct ip6_hdr *)NULL;
 103         } else {
 104                 ip = (struct ip *)NULL;
 105                 ip6 = pbuf->pb_data;
 106         }
 107         if (!pf_pull_hdr(pbuf, off, hdr, tcp->th_off << 2, NULL, NULL,
 108                 pd->af)) {
 109                 return NULL;
 110         }
 111
 112         return pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)(void *)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         struct pf_os_fingerprint fp, *fpresult;
 120         int cnt, optlen = 0;
 121         const u_int8_t *optp;
 122         char srcname[128];
 123
 124         if ((tcp->th_flags & (TH_SYN | TH_ACK)) != TH_SYN) {
 125                 return NULL;
 126         }
 127         if (ip) {
 128                 if ((ip->ip_off & htons(IP_OFFMASK)) != 0) {
 129                         return NULL;
 130                 }
 131         }
 132
 133         memset(&fp, 0, sizeof(fp));
 134
 135         if (ip) {
 136                 fp.fp_psize = ntohs(ip->ip_len);
 137                 fp.fp_ttl = ip->ip_ttl;
 138                 if (ip->ip_off & htons(IP_DF)) {
 139                         fp.fp_flags |= PF_OSFP_DF;
 140                 }
 141                 (void) inet_ntop(AF_INET, &ip->ip_src, srcname,
 142                     (socklen_t)sizeof(srcname));
 143         } else if (ip6) {
 144                 /* jumbo payload? */
 145                 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 146                 fp.fp_ttl = ip6->ip6_hlim;
 147                 fp.fp_flags |= PF_OSFP_DF;
 148                 fp.fp_flags |= PF_OSFP_INET6;
 149                 (void) inet_ntop(AF_INET6, &ip6->ip6_src, srcname,
 150                     (socklen_t)sizeof(srcname));
 151         } else {
 152                 return NULL;
 153         }
 154         fp.fp_wsize = ntohs(tcp->th_win);
 155
 156
 157         cnt = (tcp->th_off << 2) - sizeof(*tcp);
 158         optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
 159         for (; cnt > 0; cnt -= optlen, optp += optlen) {
 160                 if (*optp == TCPOPT_EOL) {
 161                         break;
 162                 }
 163
 164                 fp.fp_optcnt++;
 165                 if (*optp == TCPOPT_NOP) {
 166                         fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
 167                             PF_OSFP_TCPOPT_NOP;
 168                         optlen = 1;
 169                 } else {
 170                         if (cnt < 2) {
 171                                 return NULL;
 172                         }
 173                         optlen = optp[1];
 174                         if (optlen > cnt || optlen < 2) {
 175                                 return NULL;
 176                         }
 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                                 }
 183                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 184                                         PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
 185 #if BYTE_ORDER != BIG_ENDIAN
 186                                 NTOHS(fp.fp_mss);
 187 #endif
 188                                 break;
 189                         case TCPOPT_WINDOW:
 190                                 if (optlen >= TCPOLEN_WINDOW) {
 191                                         memcpy(&fp.fp_wscale, &optp[2],
 192                                             sizeof(fp.fp_wscale));
 193                                 }
 194                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 195                                         PF_OSFP_TCPOPT_BITS) |
 196                                     PF_OSFP_TCPOPT_WSCALE;
 197                                 break;
 198                         case TCPOPT_SACK_PERMITTED:
 199                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 200                                         PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
 201                                 break;
 202                         case TCPOPT_TIMESTAMP:
 203                                 if (optlen >= TCPOLEN_TIMESTAMP) {
 204                                         u_int32_t ts;
 205                                         memcpy(&ts, &optp[2], sizeof(ts));
 206                                         if (ts == 0) {
 207                                                 fp.fp_flags |= PF_OSFP_TS0;
 208                                         }
 209                                 }
 210                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 211                                         PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
 212                                 break;
 213                         default:
 214                                 return NULL;
 215                         }
 216                 }
 217                 optlen = MAX(optlen, 1);        /* paranoia */
 218         }
 219
 220         DPFPRINTF("fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
 221             "(TS=%s,M=%s%d,W=%s%d)\n",
 222             srcname, ntohs(tcp->th_sport),
 223             fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
 224             fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
 225             (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
 226             (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 227             (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 228             fp.fp_mss,
 229             (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 230             (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 231             fp.fp_wscale);
 232
 233         if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
 234             PF_OSFP_MAXTTL_OFFSET))) {
 235                 return &fpresult->fp_oses;
 236         }
 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         }
 251         if (list == NULL) {
 252                 DPFPRINTF("osfp no match against %x\n", os);
 253                 return os == PF_OSFP_UNKNOWN;
 254         }
 255         PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
 256         SLIST_FOREACH(entry, list, fp_entry) {
 257                 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
 258                 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
 259                     (os_version == PF_OSFP_ANY || en_version == os_version) &&
 260                     (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
 261                         DPFPRINTF("osfp matched %s %s %s  %x==%x\n",
 262                             entry->fp_class_nm, entry->fp_version_nm,
 263                             entry->fp_subtype_nm, os, entry->fp_os);
 264                         return 1;
 265                 }
 266         }
 267         DPFPRINTF("fingerprint 0x%x didn't match\n", os);
 268         return 0;
 269 }
 270
 271 /* Initialize the OS fingerprint system */
 272 void
 273 pf_osfp_initialize(void)
 274 {
 275         pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
 276             "pfosfpen", NULL);
 277         pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
 278             "pfosfp", NULL);
 279         SLIST_INIT(&pf_osfp_list);
 280 }
 281
 282 #if 0
 283 void
 284 pf_osfp_destroy(void)
 285 {
 286         pf_osfp_flush();
 287
 288         pool_destroy(&pf_osfp_pl);
 289         pool_destroy(&pf_osfp_entry_pl);
 290 }
 291 #endif
 292
 293 /* Flush the fingerprint list */
 294 void
 295 pf_osfp_flush(void)
 296 {
 297         struct pf_os_fingerprint *fp;
 298         struct pf_osfp_entry *entry;
 299
 300         while ((fp = SLIST_FIRST(&pf_osfp_list))) {
 301                 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
 302                 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
 303                         SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
 304                         pool_put(&pf_osfp_entry_pl, entry);
 305                 }
 306                 pool_put(&pf_osfp_pl, fp);
 307         }
 308 }
 309
 310
 311 /* Add a fingerprint */
 312 int
 313 pf_osfp_add(struct pf_osfp_ioctl *fpioc)
 314 {
 315         struct pf_os_fingerprint *fp, fpadd;
 316         struct pf_osfp_entry *entry, *uentry;
 317
 318         memset(&fpadd, 0, sizeof(fpadd));
 319         fpadd.fp_tcpopts = fpioc->fp_tcpopts;
 320         fpadd.fp_wsize = fpioc->fp_wsize;
 321         fpadd.fp_psize = fpioc->fp_psize;
 322         fpadd.fp_mss = fpioc->fp_mss;
 323         fpadd.fp_flags = fpioc->fp_flags;
 324         fpadd.fp_optcnt = fpioc->fp_optcnt;
 325         fpadd.fp_wscale = fpioc->fp_wscale;
 326         fpadd.fp_ttl = fpioc->fp_ttl;
 327
 328         uentry = &fpioc->fp_os;
 329         uentry->fp_entry.sle_next = NULL;
 330         uentry->fp_class_nm[sizeof(uentry->fp_class_nm) - 1] = '\0';
 331         uentry->fp_version_nm[sizeof(uentry->fp_version_nm) - 1] = '\0';
 332         uentry->fp_subtype_nm[sizeof(uentry->fp_subtype_nm) - 1] = '\0';
 333
 334         DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
 335             "(TS=%s,M=%s%d,W=%s%d) %x\n",
 336             fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
 337             fpioc->fp_os.fp_subtype_nm,
 338             (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
 339             (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
 340             (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
 341             (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
 342             fpadd.fp_wsize,
 343             fpadd.fp_ttl,
 344             (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
 345             (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
 346             (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
 347             fpadd.fp_psize,
 348             (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
 349             (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
 350             (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 351             (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 352             fpadd.fp_mss,
 353             (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 354             (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 355             fpadd.fp_wscale,
 356             fpioc->fp_os.fp_os);
 357
 358
 359         if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
 360                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 361                         if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os)) {
 362                                 return EEXIST;
 363                         }
 364                 }
 365                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_WAITOK)) == NULL) {
 366                         return ENOMEM;
 367                 }
 368         } else {
 369                 if ((fp = pool_get(&pf_osfp_pl, PR_WAITOK)) == NULL) {
 370                         return ENOMEM;
 371                 }
 372                 memset(fp, 0, sizeof(*fp));
 373                 fp->fp_tcpopts = fpioc->fp_tcpopts;
 374                 fp->fp_wsize = fpioc->fp_wsize;
 375                 fp->fp_psize = fpioc->fp_psize;
 376                 fp->fp_mss = fpioc->fp_mss;
 377                 fp->fp_flags = fpioc->fp_flags;
 378                 fp->fp_optcnt = fpioc->fp_optcnt;
 379                 fp->fp_wscale = fpioc->fp_wscale;
 380                 fp->fp_ttl = fpioc->fp_ttl;
 381                 SLIST_INIT(&fp->fp_oses);
 382                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_WAITOK)) == NULL) {
 383                         pool_put(&pf_osfp_pl, fp);
 384                         return ENOMEM;
 385                 }
 386                 pf_osfp_insert(&pf_osfp_list, fp);
 387         }
 388         memcpy(entry, &fpioc->fp_os, sizeof(*entry));
 389
 390         /* Make sure the strings are NUL terminated */
 391         entry->fp_class_nm[sizeof(entry->fp_class_nm) - 1] = '\0';
 392         entry->fp_version_nm[sizeof(entry->fp_version_nm) - 1] = '\0';
 393         entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm) - 1] = '\0';
 394
 395         SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
 396
 397 #ifdef PFDEBUG
 398         if ((fp = pf_osfp_validate())) {
 399                 printf("Invalid fingerprint list\n");
 400         }
 401 #endif /* PFDEBUG */
 402         return 0;
 403 }
 404
 405
 406 /* Find a fingerprint in the list */
 407 struct pf_os_fingerprint *
 408 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
 409     u_int8_t ttldiff)
 410 {
 411         struct pf_os_fingerprint *f;
 412
 413 #define MATCH_INT(_MOD, _DC, _field)                                    \
 414         if ((f->fp_flags & _DC) == 0) {                                 \
 415                 if ((f->fp_flags & _MOD) == 0) {                        \
 416                         if (f->_field != find->_field)                  \
 417                                 continue;                               \
 418                 } else {                                                \
 419                         if (f->_field == 0 || find->_field % f->_field) \
 420                                 continue;                               \
 421                 }                                                       \
 422         }
 423
 424         SLIST_FOREACH(f, list, fp_next) {
 425                 if (f->fp_tcpopts != find->fp_tcpopts ||
 426                     f->fp_optcnt != find->fp_optcnt ||
 427                     f->fp_ttl < find->fp_ttl ||
 428                     f->fp_ttl - find->fp_ttl > ttldiff ||
 429                     (f->fp_flags & (PF_OSFP_DF | PF_OSFP_TS0)) !=
 430                     (find->fp_flags & (PF_OSFP_DF | PF_OSFP_TS0))) {
 431                         continue;
 432                 }
 433
 434                 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
 435                 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
 436                 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
 437                 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
 438                         if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 439                                 if (find->fp_mss == 0) {
 440                                         continue;
 441                                 }
 442
 443 /*
 444  * Some "smart" NAT devices and DSL routers will tweak the MSS size and
 445  * will set it to whatever is suitable for the link type.
 446  */
 447 #define SMART_MSS       1460
 448                                 if ((find->fp_wsize % find->fp_mss ||
 449                                     find->fp_wsize / find->fp_mss !=
 450                                     f->fp_wsize) &&
 451                                     (find->fp_wsize % SMART_MSS ||
 452                                     find->fp_wsize / SMART_MSS !=
 453                                     f->fp_wsize)) {
 454                                         continue;
 455                                 }
 456                         } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 457                                 if (find->fp_mss == 0) {
 458                                         continue;
 459                                 }
 460
 461 #define MTUOFF  (sizeof (struct ip) + sizeof (struct tcphdr))
 462 #define SMART_MTU       (SMART_MSS + MTUOFF)
 463                                 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
 464                                     find->fp_wsize / (find->fp_mss + MTUOFF) !=
 465                                     f->fp_wsize) &&
 466                                     (find->fp_wsize % SMART_MTU ||
 467                                     find->fp_wsize / SMART_MTU !=
 468                                     f->fp_wsize)) {
 469                                         continue;
 470                                 }
 471                         } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 472                                 if (f->fp_wsize == 0 || find->fp_wsize %
 473                                     f->fp_wsize) {
 474                                         continue;
 475                                 }
 476                         } else {
 477                                 if (f->fp_wsize != find->fp_wsize) {
 478                                         continue;
 479                                 }
 480                         }
 481                 }
 482                 return f;
 483         }
 484
 485         return NULL;
 486 }
 487
 488 /* Find an exact fingerprint in the list */
 489 struct pf_os_fingerprint *
 490 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
 491 {
 492         struct pf_os_fingerprint *f;
 493
 494         SLIST_FOREACH(f, list, fp_next) {
 495                 if (f->fp_tcpopts == find->fp_tcpopts &&
 496                     f->fp_wsize == find->fp_wsize &&
 497                     f->fp_psize == find->fp_psize &&
 498                     f->fp_mss == find->fp_mss &&
 499                     f->fp_flags == find->fp_flags &&
 500                     f->fp_optcnt == find->fp_optcnt &&
 501                     f->fp_wscale == find->fp_wscale &&
 502                     f->fp_ttl == find->fp_ttl) {
 503                         return f;
 504                 }
 505         }
 506
 507         return NULL;
 508 }
 509
 510 /* Insert a fingerprint into the list */
 511 void
 512 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
 513 {
 514         struct pf_os_fingerprint *f, *prev = NULL;
 515
 516         /* XXX need to go semi tree based.  can key on tcp options */
 517
 518         SLIST_FOREACH(f, list, fp_next)
 519         prev = f;
 520         if (prev) {
 521                 SLIST_INSERT_AFTER(prev, ins, fp_next);
 522         } else {
 523                 SLIST_INSERT_HEAD(list, ins, fp_next);
 524         }
 525 }
 526
 527 /* Fill a fingerprint by its number (from an ioctl) */
 528 int
 529 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
 530 {
 531         struct pf_os_fingerprint *fp;
 532         struct pf_osfp_entry *entry;
 533         int num = fpioc->fp_getnum;
 534         int i = 0;
 535
 536
 537         memset(fpioc, 0, sizeof(*fpioc));
 538         SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
 539                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 540                         if (i++ == num) {
 541                                 fpioc->fp_mss = fp->fp_mss;
 542                                 fpioc->fp_wsize = fp->fp_wsize;
 543                                 fpioc->fp_flags = fp->fp_flags;
 544                                 fpioc->fp_psize = fp->fp_psize;
 545                                 fpioc->fp_ttl = fp->fp_ttl;
 546                                 fpioc->fp_wscale = fp->fp_wscale;
 547                                 fpioc->fp_getnum = num;
 548                                 memcpy(&fpioc->fp_os, entry,
 549                                     sizeof(fpioc->fp_os));
 550                                 fpioc->fp_os.fp_entry.sle_next = NULL;
 551                                 return 0;
 552                         }
 553                 }
 554         }
 555
 556         return EBUSY;
 557 }
 558
 559
 560 /* Validate that each signature is reachable */
 561 struct pf_os_fingerprint *
 562 pf_osfp_validate(void)
 563 {
 564         struct pf_os_fingerprint *f, *f2, find;
 565
 566         SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
 567                 memcpy(&find, f, sizeof(find));
 568
 569                 /* We do a few MSS/th_win percolations to make things unique */
 570                 if (find.fp_mss == 0) {
 571                         find.fp_mss = 128;
 572                 }
 573                 if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 574                         find.fp_wsize *= find.fp_mss;
 575                 } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 576                         find.fp_wsize *= (find.fp_mss + 40);
 577                 } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 578                         find.fp_wsize *= 2;
 579                 }
 580                 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
 581                         if (f2) {
 582                                 printf("Found \"%s %s %s\" instead of "
 583                                     "\"%s %s %s\"\n",
 584                                     SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
 585                                     SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
 586                                     SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
 587                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 588                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 589                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 590                         } else {
 591                                 printf("Couldn't find \"%s %s %s\"\n",
 592                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 593                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 594                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 595                         }
 596                         return f;
 597                 }
 598         }
 599         return NULL;
 600 }