sys/net/pf/pf_osfp.c

   1 /*      $OpenBSD: pf_osfp.c,v 1.15 2008/06/14 02:22:13 henning 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
  46 #else
  47 /* Userland equivalents so we can lend code to tcpdump et al. */
  48
  49 # include <arpa/inet.h>
  50 # include <errno.h>
  51 # include <stdio.h>
  52 # include <stdlib.h>
  53 # include <string.h>
  54 # include <netdb.h>
  55
  56 # ifdef PFDEBUG
  57 #  include <sys/stdarg.h>
  58 #  define DPFPRINTF(format, x...)       fprintf(stderr, format , ##x)
  59 # else
  60 #  define DPFPRINTF(format, x...)       ((void)0)
  61 # endif /* PFDEBUG */
  62 #endif /* _KERNEL */
  63
  64 static MALLOC_DEFINE(M_PFOSFPENTRYPL, "pfospfen", "pf OS finger printing pool list");
  65 static MALLOC_DEFINE(M_PFOSFPPL, "pfosfp", "pf OS finger printing pool list");
  66
  67 SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list;
  68
  69 struct pf_os_fingerprint        *pf_osfp_find(struct pf_osfp_list *,
  70                                     struct pf_os_fingerprint *, u_int8_t);
  71 struct pf_os_fingerprint        *pf_osfp_find_exact(struct pf_osfp_list *,
  72                                     struct pf_os_fingerprint *);
  73 void                             pf_osfp_insert(struct pf_osfp_list *,
  74                                     struct pf_os_fingerprint *);
  75
  76
  77 #ifdef _KERNEL
  78 /*
  79  * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only)
  80  * Returns the list of possible OSes.
  81  */
  82 struct pf_osfp_enlist *
  83 pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off,
  84     const struct tcphdr *tcp)
  85 {
  86         struct ip *ip;
  87         struct ip6_hdr *ip6;
  88         char hdr[60];
  89
  90         if ((pd->af != PF_INET && pd->af != PF_INET6) ||
  91             pd->proto != IPPROTO_TCP || (tcp->th_off << 2) < sizeof(*tcp))
  92                 return (NULL);
  93
  94         if (pd->af == PF_INET) {
  95                 ip = mtod(m, struct ip *);
  96                 ip6 = (struct ip6_hdr *)NULL;
  97         } else {
  98                 ip = (struct ip *)NULL;
  99                 ip6 = mtod(m, struct ip6_hdr *);
 100         }
 101         if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL,
 102             pd->af)) return (NULL);
 103
 104         return (pf_osfp_fingerprint_hdr(ip, ip6, (struct tcphdr *)hdr));
 105 }
 106 #endif /* _KERNEL */
 107
 108 struct pf_osfp_enlist *
 109 pf_osfp_fingerprint_hdr(const struct ip *ip, const struct ip6_hdr *ip6, const struct tcphdr *tcp)
 110 {
 111         struct pf_os_fingerprint fp, *fpresult;
 112         int cnt, optlen = 0;
 113         const u_int8_t *optp;
 114 #ifdef _KERNEL
 115         char srcname[128];
 116 #else
 117         char srcname[NI_MAXHOST];
 118 #endif
 119
 120         if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
 121                 return (NULL);
 122         if (ip) {
 123                 if ((ip->ip_off & IP_OFFMASK) != 0)
 124                         return (NULL);
 125         }
 126
 127         memset(&fp, 0, sizeof(fp));
 128
 129         if (ip) {
 130 #ifndef _KERNEL
 131                 struct sockaddr_in sin;
 132 #endif
 133
 134                 fp.fp_psize = ip->ip_len;
 135                 fp.fp_ttl = ip->ip_ttl;
 136                 if (ip->ip_off & IP_DF)
 137                         fp.fp_flags |= PF_OSFP_DF;
 138 #ifdef _KERNEL
 139                 strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
 140 #else
 141                 memset(&sin, 0, sizeof(sin));
 142                 sin.sin_family = AF_INET;
 143                 sin.sin_len = sizeof(struct sockaddr_in);
 144                 sin.sin_addr = ip->ip_src;
 145                 (void)getnameinfo((struct sockaddr *)&sin,
 146                     sizeof(struct sockaddr_in), srcname, sizeof(srcname),
 147                     NULL, 0, NI_NUMERICHOST);
 148 #endif
 149         }
 150 #ifdef INET6
 151         else if (ip6) {
 152 #ifndef _KERNEL
 153                 struct sockaddr_in6 sin6;
 154 #endif
 155
 156                 /* jumbo payload? */
 157                 fp.fp_psize = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen);
 158                 fp.fp_ttl = ip6->ip6_hlim;
 159                 fp.fp_flags |= PF_OSFP_DF;
 160                 fp.fp_flags |= PF_OSFP_INET6;
 161 #ifdef _KERNEL
 162                 strlcpy(srcname, ip6_sprintf((struct in6_addr *)&ip6->ip6_src),
 163                     sizeof(srcname));
 164 #else
 165                 memset(&sin6, 0, sizeof(sin6));
 166                 sin6.sin6_family = AF_INET6;
 167                 sin6.sin6_len = sizeof(struct sockaddr_in6);
 168                 sin6.sin6_addr = ip6->ip6_src;
 169                 (void)getnameinfo((struct sockaddr *)&sin6,
 170                     sizeof(struct sockaddr_in6), srcname, sizeof(srcname),
 171                     NULL, 0, NI_NUMERICHOST);
 172 #endif
 173         }
 174 #endif
 175         else
 176                 return (NULL);
 177         fp.fp_wsize = ntohs(tcp->th_win);
 178
 179
 180         cnt = (tcp->th_off << 2) - sizeof(*tcp);
 181         optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp));
 182         for (; cnt > 0; cnt -= optlen, optp += optlen) {
 183                 if (*optp == TCPOPT_EOL)
 184                         break;
 185
 186                 fp.fp_optcnt++;
 187                 if (*optp == TCPOPT_NOP) {
 188                         fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) |
 189                             PF_OSFP_TCPOPT_NOP;
 190                         optlen = 1;
 191                 } else {
 192                         if (cnt < 2)
 193                                 return (NULL);
 194                         optlen = optp[1];
 195                         if (optlen > cnt || optlen < 2)
 196                                 return (NULL);
 197                         switch (*optp) {
 198                         case TCPOPT_MAXSEG:
 199                                 if (optlen >= TCPOLEN_MAXSEG)
 200                                         memcpy(&fp.fp_mss, &optp[2],
 201                                             sizeof(fp.fp_mss));
 202                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 203                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS;
 204                                 fp.fp_mss = ntohs(fp.fp_mss);
 205                                 break;
 206                         case TCPOPT_WINDOW:
 207                                 if (optlen >= TCPOLEN_WINDOW)
 208                                         memcpy(&fp.fp_wscale, &optp[2],
 209                                             sizeof(fp.fp_wscale));
 210                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 211                                     PF_OSFP_TCPOPT_BITS) |
 212                                     PF_OSFP_TCPOPT_WSCALE;
 213                                 break;
 214                         case TCPOPT_SACK_PERMITTED:
 215                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 216                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK;
 217                                 break;
 218                         case TCPOPT_TIMESTAMP:
 219                                 if (optlen >= TCPOLEN_TIMESTAMP) {
 220                                         u_int32_t ts;
 221                                         memcpy(&ts, &optp[2], sizeof(ts));
 222                                         if (ts == 0)
 223                                                 fp.fp_flags |= PF_OSFP_TS0;
 224
 225                                 }
 226                                 fp.fp_tcpopts = (fp.fp_tcpopts <<
 227                                     PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS;
 228                                 break;
 229                         default:
 230                                 return (NULL);
 231                         }
 232                 }
 233                 optlen = MAX(optlen, 1);        /* paranoia */
 234         }
 235
 236         DPFPRINTF("fingerprinted %s:%d  %d:%d:%d:%d:%llx (%d) "
 237             "(TS=%s,M=%s%d,W=%s%d)\n",
 238             srcname, ntohs(tcp->th_sport),
 239             fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0,
 240             fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt,
 241             (fp.fp_flags & PF_OSFP_TS0) ? "0" : "",
 242             (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 243             (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 244             fp.fp_mss,
 245             (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 246             (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 247             fp.fp_wscale);
 248
 249         if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp,
 250             PF_OSFP_MAXTTL_OFFSET)))
 251                 return (&fpresult->fp_oses);
 252         return (NULL);
 253 }
 254
 255 /* Match a fingerprint ID against a list of OSes */
 256 int
 257 pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os)
 258 {
 259         struct pf_osfp_entry *entry;
 260         int os_class, os_version, os_subtype;
 261         int en_class, en_version, en_subtype;
 262
 263         if (os == PF_OSFP_ANY)
 264                 return (1);
 265         if (list == NULL) {
 266                 DPFPRINTF("osfp no match against %x\n", os);
 267                 return (os == PF_OSFP_UNKNOWN);
 268         }
 269         PF_OSFP_UNPACK(os, os_class, os_version, os_subtype);
 270         SLIST_FOREACH(entry, list, fp_entry) {
 271                 PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype);
 272                 if ((os_class == PF_OSFP_ANY || en_class == os_class) &&
 273                     (os_version == PF_OSFP_ANY || en_version == os_version) &&
 274                     (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) {
 275                         DPFPRINTF("osfp matched %s %s %s  %x==%x\n",
 276                             entry->fp_class_nm, entry->fp_version_nm,
 277                             entry->fp_subtype_nm, os, entry->fp_os);
 278                         return (1);
 279                 }
 280         }
 281         DPFPRINTF("fingerprint 0x%x didn't match\n", os);
 282         return (0);
 283 }
 284
 285 /* Initialize the OS fingerprint system */
 286 void
 287 pf_osfp_initialize(void)
 288 {
 289         SLIST_INIT(&pf_osfp_list);
 290 }
 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                         kfree(entry, M_PFOSFPENTRYPL);
 304                 }
 305                 kfree(fp, M_PFOSFPPL);
 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 #if 0   /* XXX RYAN wants to fix logging */
 328         DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d "
 329             "(TS=%s,M=%s%d,W=%s%d) %x\n",
 330             fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm,
 331             fpioc->fp_os.fp_subtype_nm,
 332             (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" :
 333             (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" :
 334             (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" :
 335             (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "",
 336             fpadd.fp_wsize,
 337             fpadd.fp_ttl,
 338             (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0,
 339             (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" :
 340             (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "",
 341             fpadd.fp_psize,
 342             (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt,
 343             (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "",
 344             (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" :
 345             (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "",
 346             fpadd.fp_mss,
 347             (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" :
 348             (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "",
 349             fpadd.fp_wscale,
 350             fpioc->fp_os.fp_os);
 351 #endif
 352
 353         if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) {
 354                  SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 355                         if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os))
 356                                 return (EEXIST);
 357                 }
 358                 if ((entry = kmalloc(sizeof(struct pf_osfp_entry),
 359                     M_PFOSFPENTRYPL, M_WAITOK|M_NULLOK)) == NULL)
 360                         return (ENOMEM);
 361         } else {
 362                 if ((fp = kmalloc(sizeof(struct pf_os_fingerprint),
 363                     M_PFOSFPPL, M_WAITOK|M_NULLOK)) == NULL)
 364                         return (ENOMEM);
 365                 memset(fp, 0, sizeof(*fp));
 366                 fp->fp_tcpopts = fpioc->fp_tcpopts;
 367                 fp->fp_wsize = fpioc->fp_wsize;
 368                 fp->fp_psize = fpioc->fp_psize;
 369                 fp->fp_mss = fpioc->fp_mss;
 370                 fp->fp_flags = fpioc->fp_flags;
 371                 fp->fp_optcnt = fpioc->fp_optcnt;
 372                 fp->fp_wscale = fpioc->fp_wscale;
 373                 fp->fp_ttl = fpioc->fp_ttl;
 374                 SLIST_INIT(&fp->fp_oses);
 375                 if ((entry = kmalloc(sizeof(struct pf_osfp_entry),
 376                     M_PFOSFPENTRYPL, M_WAITOK|M_NULLOK)) == NULL) {
 377                         kfree(fp, M_PFOSFPPL);
 378                         return (ENOMEM);
 379                 }
 380                 pf_osfp_insert(&pf_osfp_list, fp);
 381         }
 382         memcpy(entry, &fpioc->fp_os, sizeof(*entry));
 383
 384         /* Make sure the strings are NUL terminated */
 385         entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0';
 386         entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0';
 387         entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0';
 388
 389         SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry);
 390
 391 #ifdef PFDEBUG
 392         if ((fp = pf_osfp_validate()))
 393                 kprintf("Invalid fingerprint list\n");
 394 #endif /* PFDEBUG */
 395         return (0);
 396 }
 397
 398
 399 /* Find a fingerprint in the list */
 400 struct pf_os_fingerprint *
 401 pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find,
 402     u_int8_t ttldiff)
 403 {
 404         struct pf_os_fingerprint *f;
 405
 406 #define MATCH_INT(_MOD, _DC, _field)                                    \
 407         if ((f->fp_flags & _DC) == 0) {                                 \
 408                 if ((f->fp_flags & _MOD) == 0) {                        \
 409                         if (f->_field != find->_field)                  \
 410                                 continue;                               \
 411                 } else {                                                \
 412                         if (f->_field == 0 || find->_field % f->_field) \
 413                                 continue;                               \
 414                 }                                                       \
 415         }
 416
 417         SLIST_FOREACH(f, list, fp_next) {
 418                 if (f->fp_tcpopts != find->fp_tcpopts ||
 419                     f->fp_optcnt != find->fp_optcnt ||
 420                     f->fp_ttl < find->fp_ttl ||
 421                     f->fp_ttl - find->fp_ttl > ttldiff ||
 422                     (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) !=
 423                     (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)))
 424                         continue;
 425
 426                 MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize)
 427                 MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss)
 428                 MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale)
 429                 if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) {
 430                         if (f->fp_flags & PF_OSFP_WSIZE_MSS) {
 431                                 if (find->fp_mss == 0)
 432                                         continue;
 433
 434 /* Some "smart" NAT devices and DSL routers will tweak the MSS size and
 435  * will set it to whatever is suitable for the link type.
 436  */
 437 #define SMART_MSS       1460
 438                                 if ((find->fp_wsize % find->fp_mss ||
 439                                     find->fp_wsize / find->fp_mss !=
 440                                     f->fp_wsize) &&
 441                                     (find->fp_wsize % SMART_MSS ||
 442                                     find->fp_wsize / SMART_MSS !=
 443                                     f->fp_wsize))
 444                                         continue;
 445                         } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) {
 446                                 if (find->fp_mss == 0)
 447                                         continue;
 448
 449 #define MTUOFF  (sizeof(struct ip) + sizeof(struct tcphdr))
 450 #define SMART_MTU       (SMART_MSS + MTUOFF)
 451                                 if ((find->fp_wsize % (find->fp_mss + MTUOFF) ||
 452                                     find->fp_wsize / (find->fp_mss + MTUOFF) !=
 453                                     f->fp_wsize) &&
 454                                     (find->fp_wsize % SMART_MTU ||
 455                                     find->fp_wsize / SMART_MTU !=
 456                                     f->fp_wsize))
 457                                         continue;
 458                         } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) {
 459                                 if (f->fp_wsize == 0 || find->fp_wsize %
 460                                     f->fp_wsize)
 461                                         continue;
 462                         } else {
 463                                 if (f->fp_wsize != find->fp_wsize)
 464                                         continue;
 465                         }
 466                 }
 467                 return (f);
 468         }
 469
 470         return (NULL);
 471 }
 472
 473 /* Find an exact fingerprint in the list */
 474 struct pf_os_fingerprint *
 475 pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find)
 476 {
 477         struct pf_os_fingerprint *f;
 478
 479         SLIST_FOREACH(f, list, fp_next) {
 480                 if (f->fp_tcpopts == find->fp_tcpopts &&
 481                     f->fp_wsize == find->fp_wsize &&
 482                     f->fp_psize == find->fp_psize &&
 483                     f->fp_mss == find->fp_mss &&
 484                     f->fp_flags == find->fp_flags &&
 485                     f->fp_optcnt == find->fp_optcnt &&
 486                     f->fp_wscale == find->fp_wscale &&
 487                     f->fp_ttl == find->fp_ttl)
 488                         return (f);
 489         }
 490
 491         return (NULL);
 492 }
 493
 494 /* Insert a fingerprint into the list */
 495 void
 496 pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins)
 497 {
 498         struct pf_os_fingerprint *f, *prev = NULL;
 499
 500         /* XXX need to go semi tree based.  can key on tcp options */
 501
 502         SLIST_FOREACH(f, list, fp_next)
 503                 prev = f;
 504         if (prev)
 505                 SLIST_INSERT_AFTER(prev, ins, fp_next);
 506         else
 507                 SLIST_INSERT_HEAD(list, ins, fp_next);
 508 }
 509
 510 /* Fill a fingerprint by its number (from an ioctl) */
 511 int
 512 pf_osfp_get(struct pf_osfp_ioctl *fpioc)
 513 {
 514         struct pf_os_fingerprint *fp;
 515         struct pf_osfp_entry *entry;
 516         int num = fpioc->fp_getnum;
 517         int i = 0;
 518
 519
 520         memset(fpioc, 0, sizeof(*fpioc));
 521         SLIST_FOREACH(fp, &pf_osfp_list, fp_next) {
 522                 SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) {
 523                         if (i++ == num) {
 524                                 fpioc->fp_mss = fp->fp_mss;
 525                                 fpioc->fp_wsize = fp->fp_wsize;
 526                                 fpioc->fp_flags = fp->fp_flags;
 527                                 fpioc->fp_psize = fp->fp_psize;
 528                                 fpioc->fp_ttl = fp->fp_ttl;
 529                                 fpioc->fp_wscale = fp->fp_wscale;
 530                                 fpioc->fp_getnum = num;
 531                                 memcpy(&fpioc->fp_os, entry,
 532                                     sizeof(fpioc->fp_os));
 533                                 return (0);
 534                         }
 535                 }
 536         }
 537
 538         return (EBUSY);
 539 }
 540
 541
 542 /* Validate that each signature is reachable */
 543 struct pf_os_fingerprint *
 544 pf_osfp_validate(void)
 545 {
 546         struct pf_os_fingerprint *f, *f2, find;
 547
 548         SLIST_FOREACH(f, &pf_osfp_list, fp_next) {
 549                 memcpy(&find, f, sizeof(find));
 550
 551                 /* We do a few MSS/th_win percolations to make things unique */
 552                 if (find.fp_mss == 0)
 553                         find.fp_mss = 128;
 554                 if (f->fp_flags & PF_OSFP_WSIZE_MSS)
 555                         find.fp_wsize *= find.fp_mss;
 556                 else if (f->fp_flags & PF_OSFP_WSIZE_MTU)
 557                         find.fp_wsize *= (find.fp_mss + 40);
 558                 else if (f->fp_flags & PF_OSFP_WSIZE_MOD)
 559                         find.fp_wsize *= 2;
 560                 if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) {
 561                         if (f2)
 562                                 kprintf("Found \"%s %s %s\" instead of "
 563                                     "\"%s %s %s\"\n",
 564                                     SLIST_FIRST(&f2->fp_oses)->fp_class_nm,
 565                                     SLIST_FIRST(&f2->fp_oses)->fp_version_nm,
 566                                     SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm,
 567                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 568                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 569                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 570                         else
 571                                 kprintf("Couldn't find \"%s %s %s\"\n",
 572                                     SLIST_FIRST(&f->fp_oses)->fp_class_nm,
 573                                     SLIST_FIRST(&f->fp_oses)->fp_version_nm,
 574                                     SLIST_FIRST(&f->fp_oses)->fp_subtype_nm);
 575                         return (f);
 576                 }
 577         }
 578         return (NULL);
 579 }