sys/net/pf/pf_osfp.c

   1 /*      $OpenBSD: pf_osfp.c,v 1.12 2006/12/13 18:14:10 itojun Exp $ */
   2
   3 /*
   4  * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  */
  19
  20 #include <sys/param.h>
  21 #include <sys/socket.h>
  22 #ifdef _KERNEL
  23 # include <sys/systm.h>
  24 #endif /* _KERNEL */
  25 #include <sys/mbuf.h>
  26
  27 #include <netinet/in.h>
  28 #include <netinet/in_systm.h>
  29 #include <netinet/ip.h>
  30 #include <netinet/tcp.h>
  31
  32 #include <net/if.h>
  33 #include <net/pf/pfvar.h>
  34
  35 #include <netinet/ip6.h>
  36 #ifdef _KERNEL
  37 #include <netinet6/in6_var.h>
  38 #endif
  39
  40
  41 #ifdef _KERNEL
  42 # define DPFPRINTF(format, x...)                \
  43         if (pf_status.debug >= PF_DEBUG_NOISY)  \
  44                 kprintf(format , ##x)
  45 typedef vm_zone_t pool_t;
  46
  47 #else
  48 /* Userland equivalents so we can lend code to tcpdump et al. */
  49
  50 # include <arpa/inet.h>
  51 # include <errno.h>
  52 # include <stdio.h>
  53 # include <stdlib.h>
  54 # include <string.h>
  55 # include <netdb.h>
  56 # define pool_t                 int
  57 # define pool_get(pool, flags)  malloc(*(pool))
  58 # define pool_put(pool, item)   free(item)
  59 # define pool_init(pool, size, a, ao, f, m, p)  (*(pool)) = (size)
  60
  61 # ifdef PFDEBUG
  62 #  include <sys/stdarg.h>
  63 #  define DPFPRINTF(format, x...)       fprintf(stderr, format , ##x)
  64 # else
  65 #  define DPFPRINTF(format, x...)       ((void)0)
  66 # endif /* PFDEBUG */
  67 #endif /* _KERNEL */
  68
  69
  70 SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
  71 pool_t pf_osfp_entry_pl;
  72 pool_t pf_osfp_pl;
  73
  74 struct pf_os_fingerprint        *pf_osfp_find(struct pf_osfp_list *,
  75                                     struct pf_os_fingerprint *, u_int8_t);
  76 struct pf_os_fingerprint        *pf_osfp_find_exact(struct pf_osfp_list *,
  77                                     struct pf_os_fingerprint *);
  78 void                             pf_osfp_insert(struct pf_osfp_list *,
  79                                     struct pf_os_fingerprint *);
  80
  81
  82 #ifdef _KERNEL
  83 /*
  84  * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
  85  * Returns the list of possible OSes.
  86  */
  87 struct pf_osfp_enlist *
  88 pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
  89     const struct tcphdr *tcp)
  90 {
  91         struct ip *ip;
  92         struct ip6_hdr *ip6;
  93         char hdr[60];
  94
  95         if ((pd->af != PF_INET && pd->af != PF_INET6) ||
  96             pd->proto != IPPROTO_TCP || (tcp->th_off << 2) < sizeof(*tcp))
  97                 return (NULL);
  98
  99         if (pd->af == PF_INET) {
 100                 ip = mtod(m, struct ip *);
 101                 ip6 = (struct ip6_hdr *)NULL;
 102         } else {
 103                 ip = (struct ip *)NULL;
 104                 ip6 = mtod(m, struct ip6_hdr *);
 105         }
 106         if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
 107             pd->af)) return (NULL);
 108
 109         return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
 110 }
 111 #endif /* _KERNEL */
 112
 113 struct pf_osfp_enlist *
 114 pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6, const struct tcphdr *tcp)
 115 {
 116         struct pf_os_fingerprint fp, *fpresult;
 117         int cnt, optlen = 0;
 118         const u_int8_t *optp;
 119 #ifdef _KERNEL
 120         char srcname[128];
 121 #else
 122         char srcname[NI_MAXHOST];
 123 #endif
 124
 125         if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
 126                 return (NULL);
 127         if (ip) {
 128                 if ((ip->ip_off & htons(IP_OFFMASK)) != 0)
 129                         return (NULL);
 130         }
 131
 132         memset(&fp, 0, sizeof(fp));
 133
 134         if (ip) {
 135 #ifndef _KERNEL
 136                 struct sockaddr_in sin;
 137 #endif
 138
 139                 fp.fp_psize = ntohs(ip->ip_len);
 140                 fp.fp_ttl = ip->ip_ttl;
 141                 if (ip->ip_off & htons(IP_DF))
 142                         fp.fp_flags |= PF_OSFP_DF;
 143 #ifdef _KERNEL
 144                 strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
 145 #else
 146                 memset(&sin, 0, sizeof(sin));
 147                 sin.sin_family = AF_INET;
 148                 sin.sin_len = sizeof(struct sockaddr_in);
 149                 sin.sin_addr = ip->ip_src;
 150                 (void)getnameinfo((struct sockaddr *)&sin,
 151                     sizeof(struct sockaddr_in), srcname, sizeof(srcname),
 152                     NULL, 0, NI_NUMERICHOST);
 153 #endif
 154         }
 155 #ifdef INET6
 156         else if (ip6) {
 157 #ifndef _KERNEL
 158                 struct sockaddr_in6 sin6;
 159 #endif
 160
 161                 /* jumbo payload? */
 162                 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 163                 fp.fp_ttl = ip6->ip6_hlim;
 164                 fp.fp_flags |= PF_OSFP_DF;
 165                 fp.fp_flags |= PF_OSFP_INET6;
 166 #ifdef _KERNEL
 167                 strlcpy(srcname, ip6_sprintf((struct in6_addr *)&ip6->ip6_src),
 168                     sizeof(srcname));
 169 #else
 170                 memset(&sin6, 0, sizeof(sin6));
 171                 sin6.sin6_family = AF_INET6;
 172                 sin6.sin6_len = sizeof(struct sockaddr_in6);
 173                 sin6.sin6_addr = ip6->ip6_src;
 174                 (void)getnameinfo((struct sockaddr *)&sin6,
 175                     sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
 176                     NULL, 0, NI_NUMERICHOST);
 177 #endif
 178         }
 179 #endif
 180         else
 181                 return (NULL);
 182         fp.fp_wsize = ntohs(tcp->th_win);
 183
 184
 185         cnt = (tcp->th_off << 2) - sizeof(*tcp);
 186         optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
 187         for (; cnt > 0; cnt -= optlen, optp += optlen) {
 188                 if (*optp == TCPOPT_EOL)
 189                         break;
 190
 191                 fp.fp_optcnt++;
 192                 if (*optp == TCPOPT_NOP) {
 193                         fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
 194                             PF_OSFP_TCPOPT_NOP;
 195                         optlen = 1;
 196                 } else {
 197                         if (cnt < 2)
 198                                 return (NULL);
 199                         optlen = optp[1];
 200                         if (optlen > cnt || optlen < 2)
 201                                 return (NULL);
 202                         switch (*optp) {
 203                         case TCPOPT_MAXSEG:
 204                                 if (optlen >= TCPOLEN_MAXSEG)
 205                                         memcpy(&fp.fp_mss, &optp[2],
 206                                             sizeof(fp.fp_mss));
 207                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 208                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
 209                                 NTOHS(fp.fp_mss);
 210                                 break;
 211                         case TCPOPT_WINDOW:
 212                                 if (optlen >= TCPOLEN_WINDOW)
 213                                         memcpy(&fp.fp_wscale, &optp[2],
 214                                             sizeof(fp.fp_wscale));
 215                                 NTOHS(fp.fp_wscale);
 216                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 217                                     PF_OSFP_TCPOPT_BITS) |
 218                                     PF_OSFP_TCPOPT_WSCALE;
 219                                 break;
 220                         case TCPOPT_SACK_PERMITTED:
 221                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 222                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
 223                                 break;
 224                         case TCPOPT_TIMESTAMP:
 225                                 if (optlen >= TCPOLEN_TIMESTAMP) {
 226                                         u_int32_t ts;
 227                                         memcpy(&ts, &optp[2], sizeof(ts));
 228                                         if (ts == 0)
 229                                                 fp.fp_flags |= PF_OSFP_TS0;
 230
 231                                 }
 232                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 233                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
 234                                 break;
 235                         default:
 236                                 return (NULL);
 237                         }
 238                 }
 239                 optlen = MAX(optlen, 1);        /* paranoia */
 240         }
 241
 242         DPFPRINTF("fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
 243             "(TS=%s,M=%s%d,W=%s%d)\n",
 244             srcname, ntohs(tcp->th_sport),
 245             fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
 246             fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
 247             (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
 248             (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 249             (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 250             fp.fp_mss,
 251             (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 252             (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 253             fp.fp_wscale);
 254
 255         if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
 256             PF_OSFP_MAXTTL_OFFSET)))
 257                 return (&fpresult->fp_oses);
 258         return (NULL);
 259 }
 260
 261 /* Match a fingerprint ID against a list of OSes */
 262 int
 263 pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
 264 {
 265         struct pf_osfp_entry *entry;
 266         int os_class, os_version, os_subtype;
 267         int en_class, en_version, en_subtype;
 268
 269         if (os == PF_OSFP_ANY)
 270                 return (1);
 271         if (list == NULL) {
 272                 DPFPRINTF("osfp no match against %x\n", os);
 273                 return (os == PF_OSFP_UNKNOWN);
 274         }
 275         PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
 276         SLIST_FOREACH(entry, list, fp_entry) {
 277                 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
 278                 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
 279                     (os_version == PF_OSFP_ANY || en_version == os_version) &&
 280                     (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
 281                         DPFPRINTF("osfp matched %s %s %s  %x==%x\n",
 282                             entry->fp_class_nm, entry->fp_version_nm,
 283                             entry->fp_subtype_nm, os, entry->fp_os);
 284                         return (1);
 285                 }
 286         }
 287         DPFPRINTF("fingerprint 0x%x didn't match\n", os);
 288         return (0);
 289 }
 290
 291 /* Initialize the OS fingerprint system */
 292 int
 293 pf_osfp_initialize(void)
 294 {
 295         int error = 0;
 296
 297 #ifdef _KERNEL
 298         do {
 299                 error = ENOMEM;
 300                 pf_osfp_entry_pl = pf_osfp_pl = NULL;
 301                 ZONE_CREATE(pf_osfp_entry_pl, struct pf_osfp_entry, "pfospfen");
 302                 ZONE_CREATE(pf_osfp_pl, struct pf_os_fingerprint, "pfosfp");
 303                 error = 0;
 304         } while(0);
 305 #else
 306         pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0,
 307             "pfosfpen", NULL);
 308         pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0,
 309             "pfosfp", NULL);
 310 #endif
 311         SLIST_INIT(&pf_osfp_list);
 312
 313         return (error);
 314 }
 315
 316 #ifdef _KERNEL
 317 void
 318 pf_osfp_cleanup(void)
 319 {
 320         ZONE_DESTROY(pf_osfp_entry_pl);
 321         ZONE_DESTROY(pf_osfp_pl);
 322 }
 323 #endif
 324
 325 /* Flush the fingerprint list */
 326 void
 327 pf_osfp_flush(void)
 328 {
 329         struct pf_os_fingerprint *fp;
 330         struct pf_osfp_entry *entry;
 331
 332         while ((fp = SLIST_FIRST(&pf_osfp_list))) {
 333                 SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next);
 334                 while ((entry = SLIST_FIRST(&fp->fp_oses))) {
 335                         SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry);
 336                         pool_put(&pf_osfp_entry_pl, entry);
 337                 }
 338                 pool_put(&pf_osfp_pl, fp);
 339         }
 340 }
 341
 342
 343 /* Add a fingerprint */
 344 int
 345 pf_osfp_add(struct pf_osfp_ioctl *fpioc)
 346 {
 347         struct pf_os_fingerprint *fp, fpadd;
 348         struct pf_osfp_entry *entry;
 349
 350         memset(&fpadd, 0, sizeof(fpadd));
 351         fpadd.fp_tcpopts = fpioc->fp_tcpopts;
 352         fpadd.fp_wsize = fpioc->fp_wsize;
 353         fpadd.fp_psize = fpioc->fp_psize;
 354         fpadd.fp_mss = fpioc->fp_mss;
 355         fpadd.fp_flags = fpioc->fp_flags;
 356         fpadd.fp_optcnt = fpioc->fp_optcnt;
 357         fpadd.fp_wscale = fpioc->fp_wscale;
 358         fpadd.fp_ttl = fpioc->fp_ttl;
 359
 360         DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
 361             "(TS=%s,M=%s%d,W=%s%d) %x\n",
 362             fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
 363             fpioc->fp_os.fp_subtype_nm,
 364             (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
 365             (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
 366             (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
 367             (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
 368             fpadd.fp_wsize,
 369             fpadd.fp_ttl,
 370             (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
 371             (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
 372             (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
 373             fpadd.fp_psize,
 374             (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
 375             (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
 376             (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 377             (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 378             fpadd.fp_mss,
 379             (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 380             (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 381             fpadd.fp_wscale,
 382             fpioc->fp_os.fp_os);
 383
 384
 385         if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
 386                  SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 387                         if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
 388                                 return (EEXIST);
 389                 }
 390                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL)
 391                         return (ENOMEM);
 392         } else {
 393                 if ((fp = pool_get(&pf_osfp_pl, PR_NOWAIT)) == NULL)
 394                         return (ENOMEM);
 395                 memset(fp, 0, sizeof(*fp));
 396                 fp->fp_tcpopts = fpioc->fp_tcpopts;
 397                 fp->fp_wsize = fpioc->fp_wsize;
 398                 fp->fp_psize = fpioc->fp_psize;
 399                 fp->fp_mss = fpioc->fp_mss;
 400                 fp->fp_flags = fpioc->fp_flags;
 401                 fp->fp_optcnt = fpioc->fp_optcnt;
 402                 fp->fp_wscale = fpioc->fp_wscale;
 403                 fp->fp_ttl = fpioc->fp_ttl;
 404                 SLIST_INIT(&fp->fp_oses);
 405                 if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL) {
 406                         pool_put(&pf_osfp_pl, fp);
 407                         return (ENOMEM);
 408                 }
 409                 pf_osfp_insert(&pf_osfp_list, fp);
 410         }
 411         memcpy(entry, &fpioc->fp_os, sizeof(*entry));
 412
 413         /* Make sure the strings are NUL terminated */
 414         entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
 415         entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
 416         entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
 417
 418         SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
 419
 420 #ifdef PFDEBUG
 421         if ((fp = pf_osfp_validate()))
 422                 kprintf("Invalid fingerprint list\n");
 423 #endif /* PFDEBUG */
 424         return (0);
 425 }
 426
 427
 428 /* Find a fingerprint in the list */
 429 struct pf_os_fingerprint *
 430 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
 431     u_int8_t ttldiff)
 432 {
 433         struct pf_os_fingerprint *f;
 434
 435 #define MATCH_INT(_MOD, _DC, _field)                                    \
 436         if ((f->fp_flags & _DC) == 0) {                                 \
 437                 if ((f->fp_flags & _MOD) == 0) {                        \
 438                         if (f->_field != find->_field)                  \
 439                                 continue;                               \
 440                 } else {                                                \
 441                         if (f->_field == 0 || find->_field % f->_field) \
 442                                 continue;                               \
 443                 }                                                       \
 444         }
 445
 446         SLIST_FOREACH(f, list, fp_next) {
 447                 if (f->fp_tcpopts != find->fp_tcpopts ||
 448                     f->fp_optcnt != find->fp_optcnt ||
 449                     f->fp_ttl < find->fp_ttl ||
 450                     f->fp_ttl - find->fp_ttl > ttldiff ||
 451                     (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
 452                     (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
 453                         continue;
 454
 455                 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
 456                 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
 457                 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
 458                 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
 459                         if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 460                                 if (find->fp_mss == 0)
 461                                         continue;
 462
 463 /* Some "smart" NAT devices and DSL routers will tweak the MSS size and
 464  * will set it to whatever is suitable for the link type.
 465  */
 466 #define SMART_MSS       1460
 467                                 if ((find->fp_wsize % find->fp_mss ||
 468                                     find->fp_wsize / find->fp_mss !=
 469                                     f->fp_wsize) &&
 470                                     (find->fp_wsize % SMART_MSS ||
 471                                     find->fp_wsize / SMART_MSS !=
 472                                     f->fp_wsize))
 473                                         continue;
 474                         } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 475                                 if (find->fp_mss == 0)
 476                                         continue;
 477
 478 #define MTUOFF  (sizeof(struct ip) + sizeof(struct tcphdr))
 479 #define SMART_MTU       (SMART_MSS + MTUOFF)
 480                                 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
 481                                     find->fp_wsize / (find->fp_mss + MTUOFF) !=
 482                                     f->fp_wsize) &&
 483                                     (find->fp_wsize % SMART_MTU ||
 484                                     find->fp_wsize / SMART_MTU !=
 485                                     f->fp_wsize))
 486                                         continue;
 487                         } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 488                                 if (f->fp_wsize == 0 || find->fp_wsize %
 489                                     f->fp_wsize)
 490                                         continue;
 491                         } else {
 492                                 if (f->fp_wsize != find->fp_wsize)
 493                                         continue;
 494                         }
 495                 }
 496                 return (f);
 497         }
 498
 499         return (NULL);
 500 }
 501
 502 /* Find an exact fingerprint in the list */
 503 struct pf_os_fingerprint *
 504 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
 505 {
 506         struct pf_os_fingerprint *f;
 507
 508         SLIST_FOREACH(f, list, fp_next) {
 509                 if (f->fp_tcpopts == find->fp_tcpopts &&
 510                     f->fp_wsize == find->fp_wsize &&
 511                     f->fp_psize == find->fp_psize &&
 512                     f->fp_mss == find->fp_mss &&
 513                     f->fp_flags == find->fp_flags &&
 514                     f->fp_optcnt == find->fp_optcnt &&
 515                     f->fp_wscale == find->fp_wscale &&
 516                     f->fp_ttl == find->fp_ttl)
 517                         return (f);
 518         }
 519
 520         return (NULL);
 521 }
 522
 523 /* Insert a fingerprint into the list */
 524 void
 525 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
 526 {
 527         struct pf_os_fingerprint *f, *prev = NULL;
 528
 529         /* XXX need to go semi tree based.  can key on tcp options */
 530
 531         SLIST_FOREACH(f, list, fp_next)
 532                 prev = f;
 533         if (prev)
 534                 SLIST_INSERT_AFTER(prev, ins, fp_next);
 535         else
 536                 SLIST_INSERT_HEAD(list, ins, fp_next);
 537 }
 538
 539 /* Fill a fingerprint by its number (from an ioctl) */
 540 int
 541 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
 542 {
 543         struct pf_os_fingerprint *fp;
 544         struct pf_osfp_entry *entry;
 545         int num = fpioc->fp_getnum;
 546         int i = 0;
 547
 548
 549         memset(fpioc, 0, sizeof(*fpioc));
 550         SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
 551                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 552                         if (i++ == num) {
 553                                 fpioc->fp_mss = fp->fp_mss;
 554                                 fpioc->fp_wsize = fp->fp_wsize;
 555                                 fpioc->fp_flags = fp->fp_flags;
 556                                 fpioc->fp_psize = fp->fp_psize;
 557                                 fpioc->fp_ttl = fp->fp_ttl;
 558                                 fpioc->fp_wscale = fp->fp_wscale;
 559                                 fpioc->fp_getnum = num;
 560                                 memcpy(&fpioc->fp_os, entry,
 561                                     sizeof(fpioc->fp_os));
 562                                 return (0);
 563                         }
 564                 }
 565         }
 566
 567         return (EBUSY);
 568 }
 569
 570
 571 /* Validate that each signature is reachable */
 572 struct pf_os_fingerprint *
 573 pf_osfp_validate(void)
 574 {
 575         struct pf_os_fingerprint *f, *f2, find;
 576
 577         SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
 578                 memcpy(&find, f, sizeof(find));
 579
 580                 /* We do a few MSS/th_win percolations to make things unique */
 581                 if (find.fp_mss == 0)
 582                         find.fp_mss = 128;
 583                 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
 584                         find.fp_wsize *= find.fp_mss, 1;
 585                 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
 586                         find.fp_wsize *= (find.fp_mss + 40);
 587                 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
 588                         find.fp_wsize *= 2;
 589                 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
 590                         if (f2)
 591                                 kprintf("Found \"%s %s %s\" instead of "
 592                                     "\"%s %s %s\"\n",
 593                                     SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
 594                                     SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
 595                                     SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
 596                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 597                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 598                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 599                         else
 600                                 kprintf("Couldn't find \"%s %s %s\"\n",
 601                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 602                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 603                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 604                         return (f);
 605                 }
 606         }
 607         return (NULL);
 608 }