sys/net/if_spppfr.c

   1 /*-
   2  * Synchronous Frame Relay link level subroutines.
   3  * ANSI T1.617-compaible link management signaling
   4  * implemented for Frame Relay mode.
   5  * Cisco-type Frame Relay framing added, thanks Alex Tutubalin.
   6  * Only one DLCI per channel for now.
   7  *
   8  * Copyright (C) 1994-2000 Cronyx Engineering.
   9  * Author: Serge Vakulenko, <vak@cronyx.ru>
  10  *
  11  * Copyright (C) 1999-2004 Cronyx Engineering.
  12  * Author: Kurakin Roman, <rik@cronyx.ru>
  13  *
  14  * This software is distributed with NO WARRANTIES, not even the implied
  15  * warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  * Authors grant any other persons or organisations a permission to use,
  18  * modify and redistribute this software in source and binary forms,
  19  * as long as this message is kept with the software, all derivative
  20  * works or modified versions.
  21  *
  22  * $Cronyx Id: if_spppfr.c,v 1.1.2.10 2004/06/29 09:02:30 rik Exp $
  23  * $FreeBSD$
  24  */
  25
  26 #include <sys/param.h>
  27
  28 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
  29 #include "opt_inet.h"
  30 #include "opt_inet6.h"
  31 #include "opt_ipx.h"
  32 #endif
  33
  34 #ifdef NetBSD1_3
  35 #  if NetBSD1_3 > 6
  36 #      include "opt_inet.h"
  37 #      include "opt_inet6.h"
  38 #      include "opt_iso.h"
  39 #  endif
  40 #endif
  41
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/module.h>
  45 #include <sys/sockio.h>
  46 #include <sys/socket.h>
  47 #include <sys/syslog.h>
  48 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
  49 #include <sys/random.h>
  50 #endif
  51 #include <sys/malloc.h>
  52 #include <sys/mbuf.h>
  53
  54 #if defined (__OpenBSD__)
  55 #include <sys/md5k.h>
  56 #else
  57 #include <sys/md5.h>
  58 #endif
  59
  60 #include <net/if.h>
  61 #include <net/netisr.h>
  62 #include <net/if_types.h>
  63 #include <net/route.h>
  64 #include <netinet/in.h>
  65 #include <netinet/in_systm.h>
  66 #include <netinet/ip.h>
  67 #include <net/slcompress.h>
  68
  69 #if defined (__NetBSD__) || defined (__OpenBSD__)
  70 #include <machine/cpu.h> /* XXX for softnet */
  71 #endif
  72
  73 #include <machine/stdarg.h>
  74
  75 #include <netinet/in_var.h>
  76 #ifdef INET
  77 #include <netinet/ip.h>
  78 #include <netinet/tcp.h>
  79 #endif
  80
  81 #if defined (__FreeBSD__) || defined (__OpenBSD__)
  82 #  include <netinet/if_ether.h>
  83 #else
  84 #  include <net/ethertypes.h>
  85 #endif
  86
  87 #ifdef IPX
  88 #include <netipx/ipx.h>
  89 #include <netipx/ipx_if.h>
  90 #endif
  91
  92 #include <net/if_sppp.h>
  93
  94 /*
  95  * Frame Relay.
  96  */
  97 #define FR_UI           0x03    /* Unnumbered Information */
  98 #define FR_IP           0xCC    /* IP protocol identifier */
  99 #define FR_PADDING      0x00    /* NLPID padding */
 100 #define FR_SIGNALING    0x08    /* Q.933/T1.617 signaling identifier */
 101 #define FR_SNAP         0x80    /* NLPID snap */
 102
 103 /*
 104  * Header flags.
 105  */
 106 #define FR_DE           0x02    /* discard eligibility */
 107 #define FR_FECN         0x04    /* forward notification */
 108 #define FR_BECN         0x08    /* backward notification */
 109
 110 /*
 111  * Signaling message types.
 112  */
 113 #define FR_MSG_ENQUIRY  0x75    /* status enquiry */
 114 #define FR_MSG_STATUS   0x7d    /* status */
 115
 116 #define FR_ENQUIRY_SIZE 14
 117
 118 /*
 119  * Message field types.
 120  */
 121 #define FR_FLD_RTYPE    0x01    /* report type */
 122 #define FR_FLD_VERIFY   0x03    /* link verification */
 123 #define FR_FLD_PVC      0x07    /* PVC status */
 124 #define FR_FLD_LSHIFT5  0x95    /* locking shift 5 */
 125
 126 /*
 127  * Report types.
 128  */
 129 #define FR_RTYPE_FULL   0       /* full status */
 130 #define FR_RTYPE_SHORT  1       /* link verification only */
 131 #define FR_RTYPE_SINGLE 2       /* single PVC status */
 132
 133 /* PVC status field. */
 134 #define FR_DLCI_DELETE  0x04    /* PVC is deleted */
 135 #define FR_DLCI_ACTIVE  0x02    /* PVC is operational */
 136 #define FR_DLCI_NEW     0x08    /* PVC is new */
 137
 138 struct arp_req {
 139         unsigned short  htype;          /* hardware type = ARPHRD_FRELAY */
 140         unsigned short  ptype;          /* protocol type = ETHERTYPE_IP */
 141         unsigned char   halen;          /* hardware address length = 2 */
 142         unsigned char   palen;          /* protocol address length = 4 */
 143         unsigned short  op;             /* ARP/RARP/InARP request/reply */
 144         unsigned short  hsource;        /* hardware source address */
 145         unsigned short  psource1;       /* protocol source */
 146         unsigned short  psource2;
 147         unsigned short  htarget;        /* hardware target address */
 148         unsigned short  ptarget1;       /* protocol target */
 149         unsigned short  ptarget2;
 150 } __packed;
 151
 152 #if defined(__FreeBSD__) && __FreeBSD__ >= 3 && __FreeBSD_version < 501113
 153 #define SPP_FMT         "%s%d: "
 154 #define SPP_ARGS(ifp)   (ifp)->if_name, (ifp)->if_unit
 155 #else
 156 #define SPP_FMT         "%s: "
 157 #define SPP_ARGS(ifp)   (ifp)->if_xname
 158 #endif
 159
 160 /* almost every function needs these */
 161 #define STDDCL                                                  \
 162         struct ifnet *ifp = SP2IFP(sp);                         \
 163         int debug = ifp->if_flags & IFF_DEBUG
 164
 165 static void sppp_fr_arp (struct sppp *sp, struct arp_req *req, u_short addr);
 166 static void sppp_fr_signal (struct sppp *sp, unsigned char *h, int len);
 167
 168 void sppp_fr_input (struct sppp *sp, struct mbuf *m)
 169 {
 170         STDDCL;
 171         u_char *h = mtod (m, u_char*);
 172         int isr = -1;
 173         int dlci, hlen, proto;
 174
 175         /* Get the DLCI number. */
 176         if (m->m_pkthdr.len < 10) {
 177 bad:            m_freem (m);
 178                 return;
 179         }
 180         dlci = (h[0] << 2 & 0x3f0) | (h[1] >> 4 & 0x0f);
 181
 182         /* Process signaling packets. */
 183         if (dlci == 0) {
 184                 sppp_fr_signal (sp, h, m->m_pkthdr.len);
 185                 m_freem (m);
 186                 return;
 187         }
 188
 189         if (dlci != sp->fr_dlci) {
 190                 if (debug)
 191                         printf (SPP_FMT "Received packet from invalid DLCI %d\n",
 192                                 SPP_ARGS(ifp), dlci);
 193                 goto bad;
 194         }
 195
 196         /* Process the packet. */
 197         if (ntohs (*(short*) (h+2)) == ETHERTYPE_IP) {
 198                 /* Prehistoric IP framing? */
 199                 h[2] = FR_UI;
 200                 h[3] = FR_IP;
 201         }
 202         if (h[2] != FR_UI) {
 203                 if (debug)
 204                         printf (SPP_FMT "Invalid frame relay header flag 0x%02x\n",
 205                                 SPP_ARGS(ifp), h[2]);
 206                 goto bad;
 207         }
 208         switch (h[3]) {
 209         default:
 210                 if (debug)
 211                         printf (SPP_FMT "Unsupported NLPID 0x%02x\n",
 212                                 SPP_ARGS(ifp), h[3]);
 213                 goto bad;
 214
 215         case FR_PADDING:
 216                 if (h[4] != FR_SNAP) {
 217                         if (debug)
 218                                 printf (SPP_FMT "Bad NLPID 0x%02x\n",
 219                                         SPP_ARGS(ifp), h[4]);
 220                         goto bad;
 221                 }
 222                 if (h[5] || h[6] || h[7]) {
 223                         if (debug)
 224                                 printf (SPP_FMT "Bad OID 0x%02x-0x%02x-0x%02x\n",
 225                                         SPP_ARGS(ifp),
 226                                         h[5], h[6], h[7]);
 227                         goto bad;
 228                 }
 229                 proto = ntohs (*(short*) (h+8));
 230                 if (proto == ETHERTYPE_ARP) {
 231                         /* Process the ARP request. */
 232                         if (m->m_pkthdr.len != 10 + sizeof (struct arp_req)) {
 233                                 if (debug)
 234                                         printf (SPP_FMT "Bad ARP request size = %d bytes\n",
 235                                                 SPP_ARGS(ifp),
 236                                                 m->m_pkthdr.len);
 237                                 goto bad;
 238                         }
 239                         sppp_fr_arp (sp, (struct arp_req*) (h + 10),
 240                                 h[0] << 8 | h[1]);
 241                         m_freem (m);
 242                         return;
 243                 }
 244                 hlen = 10;
 245                 break;
 246
 247         case FR_IP:
 248                 proto = ETHERTYPE_IP;
 249                 hlen = 4;
 250                 break;
 251         }
 252
 253         /* Remove frame relay header. */
 254         m_adj (m, hlen);
 255
 256         switch (proto) {
 257         default:
 258                 ++ifp->if_noproto;
 259 drop:           ++ifp->if_ierrors;
 260                 ++ifp->if_iqdrops;
 261                 m_freem (m);
 262                 return;
 263 #ifdef INET
 264         case ETHERTYPE_IP:
 265                 isr = NETISR_IP;
 266                 break;
 267 #endif
 268 #ifdef IPX
 269         case ETHERTYPE_IPX:
 270                 isr = NETISR_IPX;
 271                 break;
 272 #endif
 273 #ifdef NETATALK
 274         case ETHERTYPE_AT:
 275                 isr = NETISR_ATALK;
 276                 break;
 277 #endif
 278         }
 279
 280         if (! (ifp->if_flags & IFF_UP))
 281                 goto drop;
 282
 283         /* Check queue. */
 284         if (netisr_queue(isr, m)) {     /* (0) on success. */
 285                 if (debug)
 286                         log(LOG_DEBUG, SPP_FMT "protocol queue overflow\n",
 287                                 SPP_ARGS(ifp));
 288         }
 289 }
 290
 291 /*
 292  * Add the frame relay header to the packet.
 293  * For IP the header length is 4 bytes,
 294  * for all other protocols - 10 bytes (RFC 1490).
 295  */
 296 struct mbuf *sppp_fr_header (struct sppp *sp, struct mbuf *m,
 297         int family)
 298 {
 299         STDDCL;
 300         u_char *h;
 301         int type, hlen;
 302
 303         /* Prepend the space for Frame Relay header. */
 304         hlen = (family == AF_INET) ? 4 : 10;
 305         M_PREPEND (m, hlen, M_DONTWAIT);
 306         if (! m)
 307                 return 0;
 308         h = mtod (m, u_char*);
 309
 310         /* Fill the header. */
 311         h[0] = sp->fr_dlci >> 2 & 0xfc;
 312         h[1] = sp->fr_dlci << 4 | 1;
 313         h[2] = FR_UI;
 314
 315         switch (family) {
 316         default:
 317                 if (debug)
 318                         printf (SPP_FMT "Cannot handle address family %d\n",
 319                                 SPP_ARGS(ifp), family);
 320                 m_freem (m);
 321                 return 0;
 322 #ifdef INET
 323         case AF_INET:
 324 #if 0 /* Crashes on fragmented packets */
 325                 /*
 326                  * Set the discard eligibility bit, if:
 327                  * 1) no fragmentation
 328                  * 2) length > 400 bytes
 329                  * 3a) the protocol is UDP or
 330                  * 3b) TCP data (no control bits)
 331                  */
 332                 {
 333                 struct ip *ip = (struct ip*) (h + hlen);
 334                 struct tcphdr *tcp = (struct tcphdr*) ((long*)ip + ip->ip_hl);
 335
 336                 if (! (ip->ip_off & ~IP_DF) && ip->ip_len > 400 &&
 337                     (ip->ip_p == IPPROTO_UDP ||
 338                     ip->ip_p == IPPROTO_TCP && ! tcp->th_flags))
 339                         h[1] |= FR_DE;
 340                 }
 341 #endif
 342                 h[3] = FR_IP;
 343                 return m;
 344 #endif
 345 #ifdef IPX
 346         case AF_IPX:
 347                 type = ETHERTYPE_IPX;
 348                 break;
 349 #endif
 350 #ifdef NS
 351         case AF_NS:
 352                 type = 0x8137;
 353                 break;
 354 #endif
 355 #ifdef NETATALK
 356         case AF_APPLETALK:
 357                 type = ETHERTYPE_AT;
 358                 break;
 359 #endif
 360         }
 361         h[3] = FR_PADDING;
 362         h[4] = FR_SNAP;
 363         h[5] = 0;
 364         h[6] = 0;
 365         h[7] = 0;
 366         *(short*) (h+8) = htons(type);
 367         return m;
 368 }
 369
 370 /*
 371  * Send periodical frame relay link verification messages via DLCI 0.
 372  * Called every 10 seconds (default value of T391 timer is 10 sec).
 373  * Every 6-th message is a full status request
 374  * (default value of N391 counter is 6).
 375  */
 376 void sppp_fr_keepalive (struct sppp *sp)
 377 {
 378         STDDCL;
 379         unsigned char *h, *p;
 380         struct mbuf *m;
 381
 382         MGETHDR (m, M_DONTWAIT, MT_DATA);
 383         if (! m)
 384                 return;
 385         m->m_pkthdr.rcvif = 0;
 386
 387         h = mtod (m, u_char*);
 388         p = h;
 389         *p++ = 0;                       /* DLCI = 0 */
 390         *p++ = 1;
 391         *p++ = FR_UI;
 392         *p++ = FR_SIGNALING;            /* NLPID = UNI call control */
 393
 394         *p++ = 0;                       /* call reference length = 0 */
 395         *p++ = FR_MSG_ENQUIRY;          /* message type = status enquiry */
 396
 397         *p++ = FR_FLD_LSHIFT5;          /* locking shift 5 */
 398
 399         *p++ = FR_FLD_RTYPE;            /* report type field */
 400         *p++ = 1;                       /* report type length = 1 */
 401         if (sp->pp_seq[IDX_LCP] % 6)
 402                 *p++ = FR_RTYPE_SHORT;  /* link verification only */
 403         else
 404                 *p++ = FR_RTYPE_FULL;   /* full status needed */
 405
 406         if (sp->pp_seq[IDX_LCP] >= 255)
 407                 sp->pp_seq[IDX_LCP] = 0;
 408         *p++ = FR_FLD_VERIFY;           /* link verification type field */
 409         *p++ = 2;                       /* link verification field length = 2 */
 410         *p++ = ++sp->pp_seq[IDX_LCP];   /* our sequence number */
 411         *p++ = sp->pp_rseq[IDX_LCP];    /* last received sequence number */
 412
 413         m->m_pkthdr.len = m->m_len = p - h;
 414         if (debug)
 415                 printf (SPP_FMT "send lmi packet, seq=%d, rseq=%d\n",
 416                         SPP_ARGS(ifp), (u_char) sp->pp_seq[IDX_LCP],
 417                         (u_char) sp->pp_rseq[IDX_LCP]);
 418
 419         if (! IF_HANDOFF_ADJ(&sp->pp_cpq, m, ifp, 3))
 420                 ++ifp->if_oerrors;
 421 }
 422
 423 /*
 424  * Process the frame relay Inverse ARP request.
 425  */
 426 static void sppp_fr_arp (struct sppp *sp, struct arp_req *req,
 427         u_short his_hardware_address)
 428 {
 429         STDDCL;
 430         struct mbuf *m;
 431         struct arp_req *reply;
 432         u_char *h;
 433         u_short my_hardware_address;
 434         u_long his_ip_address, my_ip_address;
 435
 436         if ((ntohs (req->htype) != ARPHRD_FRELAY ||
 437             ntohs (req->htype) != 16) || /* for BayNetworks routers */
 438             ntohs (req->ptype) != ETHERTYPE_IP) {
 439                 if (debug)
 440                         printf (SPP_FMT "Invalid ARP hardware/protocol type = 0x%x/0x%x\n",
 441                                 SPP_ARGS(ifp),
 442                                 ntohs (req->htype), ntohs (req->ptype));
 443                 return;
 444         }
 445         if (req->halen != 2 || req->palen != 4) {
 446                 if (debug)
 447                         printf (SPP_FMT "Invalid ARP hardware/protocol address length = %d/%d\n",
 448                                 SPP_ARGS(ifp),
 449                                 req->halen, req->palen);
 450                 return;
 451         }
 452         switch (ntohs (req->op)) {
 453         default:
 454                 if (debug)
 455                         printf (SPP_FMT "Invalid ARP op = 0x%x\n",
 456                                 SPP_ARGS(ifp), ntohs (req->op));
 457                 return;
 458
 459         case ARPOP_INVREPLY:
 460                 /* Ignore. */
 461                 return;
 462
 463         case ARPOP_INVREQUEST:
 464                 my_hardware_address = ntohs (req->htarget);
 465                 his_ip_address = ntohs (req->psource1) << 16 |
 466                         ntohs (req->psource2);
 467                 my_ip_address = ntohs (req->ptarget1) << 16 |
 468                         ntohs (req->ptarget2);
 469                 break;
 470         }
 471         if (debug)
 472                 printf (SPP_FMT "got ARP request, source=0x%04x/%d.%d.%d.%d, target=0x%04x/%d.%d.%d.%d\n",
 473                         SPP_ARGS(ifp), ntohs (req->hsource),
 474                         (unsigned char) (his_ip_address >> 24),
 475                         (unsigned char) (his_ip_address >> 16),
 476                         (unsigned char) (his_ip_address >> 8),
 477                         (unsigned char) his_ip_address,
 478                         my_hardware_address,
 479                         (unsigned char) (my_ip_address >> 24),
 480                         (unsigned char) (my_ip_address >> 16),
 481                         (unsigned char) (my_ip_address >> 8),
 482                         (unsigned char) my_ip_address);
 483
 484         sppp_get_ip_addrs (sp, &my_ip_address, 0, 0);
 485         if (! my_ip_address)
 486                 return;         /* nothing to reply */
 487
 488         if (debug)
 489                 printf (SPP_FMT "send ARP reply, source=0x%04x/%d.%d.%d.%d, target=0x%04x/%d.%d.%d.%d\n",
 490                         SPP_ARGS(ifp), my_hardware_address,
 491                         (unsigned char) (my_ip_address >> 24),
 492                         (unsigned char) (my_ip_address >> 16),
 493                         (unsigned char) (my_ip_address >> 8),
 494                         (unsigned char) my_ip_address,
 495                         his_hardware_address,
 496                         (unsigned char) (his_ip_address >> 24),
 497                         (unsigned char) (his_ip_address >> 16),
 498                         (unsigned char) (his_ip_address >> 8),
 499                         (unsigned char) his_ip_address);
 500
 501         /* Send the Inverse ARP reply. */
 502         MGETHDR (m, M_DONTWAIT, MT_DATA);
 503         if (! m)
 504                 return;
 505         m->m_pkthdr.len = m->m_len = 10 + sizeof (*reply);
 506         m->m_pkthdr.rcvif = 0;
 507
 508         h = mtod (m, u_char*);
 509         reply = (struct arp_req*) (h + 10);
 510
 511         h[0] = his_hardware_address >> 8;
 512         h[1] = his_hardware_address;
 513         h[2] = FR_UI;
 514         h[3] = FR_PADDING;
 515         h[4] = FR_SNAP;
 516         h[5] = 0;
 517         h[6] = 0;
 518         h[7] = 0;
 519         *(short*) (h+8) = htons (ETHERTYPE_ARP);
 520
 521         reply->htype    = htons (ARPHRD_FRELAY);
 522         reply->ptype    = htons (ETHERTYPE_IP);
 523         reply->halen    = 2;
 524         reply->palen    = 4;
 525         reply->op       = htons (ARPOP_INVREPLY);
 526         reply->hsource  = htons (my_hardware_address);
 527         reply->psource1 = htonl (my_ip_address);
 528         reply->psource2 = htonl (my_ip_address) >> 16;
 529         reply->htarget  = htons (his_hardware_address);
 530         reply->ptarget1 = htonl (his_ip_address);
 531         reply->ptarget2 = htonl (his_ip_address) >> 16;
 532
 533         if (! IF_HANDOFF_ADJ(&sp->pp_cpq, m, ifp, 3))
 534                 ++ifp->if_oerrors;
 535 }
 536
 537 /*
 538  * Process the input signaling packet (DLCI 0).
 539  * The implemented protocol is ANSI T1.617 Annex D.
 540  */
 541 static void sppp_fr_signal (struct sppp *sp, unsigned char *h, int len)
 542 {
 543         STDDCL;
 544         u_char *p;
 545         int dlci;
 546
 547         if (h[2] != FR_UI || h[3] != FR_SIGNALING || h[4] != 0) {
 548                 if (debug)
 549                         printf (SPP_FMT "Invalid signaling header\n",
 550                                 SPP_ARGS(ifp));
 551 bad:            if (debug) {
 552                         printf ("%02x", *h++);
 553                         while (--len > 0)
 554                                 printf ("-%02x", *h++);
 555                         printf ("\n");
 556                 }
 557                 return;
 558         }
 559         if (h[5] == FR_MSG_ENQUIRY) {
 560                 if (len == FR_ENQUIRY_SIZE &&
 561                     h[12] == (u_char) sp->pp_seq[IDX_LCP]) {
 562                         sp->pp_seq[IDX_LCP] = random();
 563                         printf (SPP_FMT "loopback detected\n",
 564                                 SPP_ARGS(ifp));
 565                 }
 566                 return;
 567         }
 568         if (h[5] != FR_MSG_STATUS) {
 569                 if (debug)
 570                         printf (SPP_FMT "Unknown signaling message: 0x%02x\n",
 571                                 SPP_ARGS(ifp), h[5]);
 572                 goto bad;
 573         }
 574
 575         /* Parse message fields. */
 576         for (p=h+6; p<h+len; ) {
 577                 switch (*p) {
 578                 default:
 579                         if (debug)
 580                                 printf (SPP_FMT "Unknown signaling field 0x%x\n",
 581                                         SPP_ARGS(ifp), *p);
 582                         break;
 583                 case FR_FLD_LSHIFT5:
 584                 case FR_FLD_RTYPE:
 585                         /* Ignore. */
 586                         break;
 587                 case FR_FLD_VERIFY:
 588                         if (p[1] != 2) {
 589                                 if (debug)
 590                                         printf (SPP_FMT "Invalid signaling verify field length %d\n",
 591                                                 SPP_ARGS(ifp), p[1]);
 592                                 break;
 593                         }
 594                         sp->pp_rseq[IDX_LCP] = p[2];
 595                         if (debug) {
 596                                 printf (SPP_FMT "got lmi reply rseq=%d, seq=%d",
 597                                         SPP_ARGS(ifp), p[2], p[3]);
 598                                 if (p[3] != (u_char) sp->pp_seq[IDX_LCP])
 599                                         printf (" (really %d)",
 600                                                 (u_char) sp->pp_seq[IDX_LCP]);
 601                                 printf ("\n");
 602                         }
 603                         break;
 604                 case FR_FLD_PVC:
 605                         if (p[1] < 3) {
 606                                 if (debug)
 607                                         printf (SPP_FMT "Invalid PVC status length %d\n",
 608                                                 SPP_ARGS(ifp), p[1]);
 609                                 break;
 610                         }
 611                         dlci = (p[2] << 4 & 0x3f0) | (p[3] >> 3 & 0x0f);
 612                         if (! sp->fr_dlci)
 613                                 sp->fr_dlci = dlci;
 614                         if (sp->fr_status != p[4])
 615                                 printf (SPP_FMT "DLCI %d %s%s\n",
 616                                         SPP_ARGS(ifp), dlci,
 617                                         p[4] & FR_DLCI_DELETE ? "deleted" :
 618                                         p[4] & FR_DLCI_ACTIVE ? "active" : "passive",
 619                                         p[4] & FR_DLCI_NEW ? ", new" : "");
 620                         sp->fr_status = p[4];
 621                         break;
 622                 }
 623                 if (*p & 0x80)
 624                         ++p;
 625                 else if (p < h+len+1 && p[1])
 626                         p += 2 + p[1];
 627                 else {
 628                         if (debug)
 629                                 printf (SPP_FMT "Invalid signaling field 0x%x\n",
 630                                         SPP_ARGS(ifp), *p);
 631                         goto bad;
 632                 }
 633         }
 634 }