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print-fr.c

/*
 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static const char rcsid[] _U_ =
      "@(#)$Header: /tcpdump/master/tcpdump/print-fr.c,v 1.17.2.3 2003/12/15 03:37:45 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <string.h>
#include <pcap.h>

#include "addrtoname.h"
#include "interface.h"
#include "ethertype.h"
#include "extract.h"

static void lmi_print(const u_char *, u_int);

#define NLPID_LMI       0x08   /* ANSI T1.617 Annex D or ITU-T Q.933 Annex A */
#define NLPID_CISCO_LMI 0x09   /* The original, aka Cisco, aka Gang of Four */
#define NLPID_SNAP      0x80
#define NLPID_CLNP      0x81
#define NLPID_ESIS      0x82
#define NLPID_ISIS      0x83
#define NLPID_CONS      0x84
#define NLPID_IDRP      0x85
#define NLPID_X25_ESIS  0x8a
#define NLPID_IPV6      0x8e
#define NLPID_IP        0xcc

#define FR_EA_BIT 0x01


/* Finds out Q.922 address length, DLCI and flags. Returns 0 on success */
static int parse_q922_addr(const u_char *p, u_int *dlci, u_int *addr_len,
                     char **flags_ptr)
{
      static char flags[32];
      size_t len;

      if ((p[0] & FR_EA_BIT))
            return -1;

      *flags_ptr = flags;
      *addr_len = 2;
      *dlci = ((p[0] & 0xFC) << 2) | ((p[1] & 0xF0) >> 4);

      strcpy(flags, (p[0] & 0x02) ? "C!, " : "");
      if (p[1] & 0x08)
            strcat(flags, "FECN, ");
      if (p[1] & 0x04)
            strcat(flags, "BECN, ");
      if (p[1] & 0x02)
            strcat(flags, "DE, ");

      len = strlen(flags);
      if (len > 1)
            flags[len - 2] = '\x0'; /* delete trailing comma and space */

      if (p[1] & FR_EA_BIT)
            return 0;   /* 2-byte Q.922 address */

      p += 2;
      (*addr_len)++;          /* 3- or 4-byte Q.922 address */
      if ((p[0] & FR_EA_BIT) == 0) {
            *dlci = (*dlci << 7) | (p[0] >> 1);
            (*addr_len)++;    /* 4-byte Q.922 address */
            p++;
      }

      if ((p[0] & FR_EA_BIT) == 0)
            return -1; /* more than 4 bytes of Q.922 address? */

      if (p[0] & 0x02) {
            len = strlen(flags);
            snprintf(flags + len, sizeof(flags) - len,
                   "%sdlcore %x", len ? ", " : "", p[0] >> 2);
      } else
            *dlci = (*dlci << 6) | (p[0] >> 2);

      return 0;
}


static const char *fr_nlpids[256];

static void
init_fr_nlpids(void)
{
      int i;
      static int fr_nlpid_flag = 0;

      if (!fr_nlpid_flag) {
            for (i=0; i < 256; i++)
                  fr_nlpids[i] = NULL;
            fr_nlpids[NLPID_LMI] = "LMI";
            fr_nlpids[NLPID_CISCO_LMI] = "Cisco LMI";
            fr_nlpids[NLPID_SNAP] = "SNAP";
            fr_nlpids[NLPID_CLNP] = "CLNP";
            fr_nlpids[NLPID_ESIS] = "ESIS";
            fr_nlpids[NLPID_ISIS] = "ISIS";
            fr_nlpids[NLPID_CONS] = "CONS";
            fr_nlpids[NLPID_IDRP] = "IDRP";
            fr_nlpids[NLPID_X25_ESIS] = "X25_ESIS";
            fr_nlpids[NLPID_IP] = "IP";
      }
      fr_nlpid_flag = 1;
}

/* Frame Relay packet structure, with flags and CRC removed

                  +---------------------------+
                  |       Q.922 Address*      |
                  +--                       --+
                  |                           |
                  +---------------------------+
                  | Control (UI = 0x03)       |
                  +---------------------------+
                  | Optional Pad      (0x00)  |
                  +---------------------------+
                  | NLPID                     |
                  +---------------------------+
                  |             .             |
                  |             .             |
                  |             .             |
                  |           Data            |
                  |             .             |
                  |             .             |
                  +---------------------------+

           * Q.922 addresses, as presently defined, are two octets and
             contain a 10-bit DLCI.  In some networks Q.922 addresses
             may optionally be increased to three or four octets.
*/

static u_int
fr_hdrlen(const u_char *p, u_int addr_len, u_int caplen)
{
      if ((caplen > addr_len + 1 /* UI */ + 1 /* pad */) &&
          !p[addr_len + 1] /* pad exist */)
            return addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
      else 
            return addr_len + 1 /* UI */ + 1 /* NLPID */;
}

static const char *
fr_protostring(u_int8_t proto)
{
      static char buf[5+1+2+1];

      init_fr_nlpids();

      if (nflag || fr_nlpids[proto] == NULL) {
            snprintf(buf, sizeof(buf), "proto %02x", proto);
            return buf;
      }
      return fr_nlpids[proto];
}

static void
fr_hdr_print(int length, u_int dlci, char *flags, u_char nlpid)
{
      if (qflag)
            (void)printf("DLCI %u, %s%slength %d: ",
                       dlci, flags, *flags ? ", " : "", length);
      else
            (void)printf("DLCI %u, %s%s%s, length %d: ",
                       dlci, flags, *flags ? ", " : "",
                       fr_protostring(nlpid), length);
}

u_int
fr_if_print(const struct pcap_pkthdr *h, register const u_char *p)
{
      register u_int length = h->len;
      register u_int caplen = h->caplen;
      u_short extracted_ethertype;
      u_int32_t orgcode;
      register u_short et;
      u_int dlci;
      int addr_len;
      u_char nlpid;
      u_int hdr_len;
      char *flags;

      if (caplen < 4) { /* minimum frame header length */
            printf("[|fr]");
            return caplen;
      }

      if (parse_q922_addr(p, &dlci, &addr_len, &flags)) {
            printf("Invalid Q.922 address");
            return caplen;
      }

      hdr_len = fr_hdrlen(p, addr_len, caplen);

      if (caplen < hdr_len) {
            printf("[|fr]");
            return caplen;
      }

      if (p[addr_len] != 0x03)
            printf("UI %02x! ", p[addr_len]);

      if (!p[addr_len + 1]) { /* pad byte should be used with 3-byte Q.922 */
            if (addr_len != 3)
                  printf("Pad! ");
      } else if (addr_len == 3)
            printf("No pad! ");

      nlpid = p[hdr_len - 1];

      p += hdr_len;
      length -= hdr_len;
      caplen -= hdr_len;

      if (eflag)
            fr_hdr_print(length, dlci, flags, nlpid);

      switch (nlpid) {
      case NLPID_IP:
            ip_print(p, length);
            break;

#ifdef INET6
      case NLPID_IPV6:
            ip6_print(p, length);
            break;
#endif
      case NLPID_CLNP:
      case NLPID_ESIS:
      case NLPID_ISIS:
            isoclns_print(p, length, caplen);
            break;

      case NLPID_SNAP:
            orgcode = EXTRACT_24BITS(p);
            et = EXTRACT_16BITS(p + 3);
            if (snap_print((const u_char *)(p + 5), length - 5,
                     caplen - 5, &extracted_ethertype, orgcode, et,
                     0) == 0) {
                  /* ether_type not known, print raw packet */
                  if (!eflag)
                        fr_hdr_print(length + hdr_len,
                                   dlci, flags, nlpid);
                  if (extracted_ethertype) {
                        printf("(SNAP %s) ",
                         etherproto_string(htons(extracted_ethertype)));
                  }
                  if (!xflag && !qflag)
                        default_print(p - hdr_len, caplen + hdr_len);
            }
            break;

      case NLPID_LMI:
            lmi_print(p, length);
            break;

      default:
            if (!eflag)
                  fr_hdr_print(length + hdr_len,
                             dlci, flags, nlpid);
            if (!xflag)
                  default_print(p, caplen);
      }

      return hdr_len;
}

/*
 * Q.933 decoding portion for framerelay specific.
 */

/* Q.933 packet format
                      Format of Other Protocols   
                          using Q.933 NLPID
                  +-------------------------------+            
                  |        Q.922 Address          | 
                  +---------------+---------------+
                  |Control  0x03  | NLPID   0x08  |        
                  +---------------+---------------+        
                  |          L2 Protocol ID       |
                  | octet 1       |  octet 2      |
                  +-------------------------------+
                  |          L3 Protocol ID       |
                  | octet 2       |  octet 2      |
                  +-------------------------------+
                  |         Protocol Data         |
                  +-------------------------------+
                  | FCS                           |
                  +-------------------------------+
 */

/* L2 (Octet 1)- Call Reference Usually is 0x0 */

/*
 * L2 (Octet 2)- Message Types definition 1 byte long.
 */
/* Call Establish */
#define MSG_TYPE_ESC_TO_NATIONAL  0x00
#define MSG_TYPE_ALERT            0x01
#define MSG_TYPE_CALL_PROCEEDING  0x02
#define MSG_TYPE_CONNECT          0x07
#define MSG_TYPE_CONNECT_ACK      0x0F
#define MSG_TYPE_PROGRESS         0x03
#define MSG_TYPE_SETUP            0x05
/* Call Clear */
#define MSG_TYPE_DISCONNECT       0x45
#define MSG_TYPE_RELEASE          0x4D
#define MSG_TYPE_RELEASE_COMPLETE 0x5A
#define MSG_TYPE_RESTART          0x46
#define MSG_TYPE_RESTART_ACK      0x4E
/* Status */
#define MSG_TYPE_STATUS           0x7D
#define MSG_TYPE_STATUS_ENQ       0x75

#define MSG_ANSI_LOCKING_SHIFT      0x95
#define ONE_BYTE_IE_MASK      0xF0 /* details? */

#define ANSI_REPORT_TYPE_IE   0x01
#define ANSI_LINK_VERIFY_IE_91      0x19 /* details? */
#define ANSI_LINK_VERIFY_IE   0x03
#define ANSI_PVC_STATUS_IE    0x07

#define CCITT_REPORT_TYPE_IE  0x51
#define CCITT_LINK_VERIFY_IE  0x53
#define CCITT_PVC_STATUS_IE   0x57

struct common_ie_header {
    u_int8_t ie_id;
    u_int8_t ie_len;
};

#define FULL_STATUS 0
#define LINK_VERIFY 1
#define ASYNC_PVC   2


/* Parses DLCI information element. */
static const char * parse_dlci_ie(const u_char *p, u_int ie_len, char *buffer,
                      size_t buffer_len)
{
      u_int dlci;

      if ((ie_len < 3) ||
          (p[0] & 0x80) ||
          ((ie_len == 3) && !(p[1] & 0x80)) ||
          ((ie_len == 4) && ((p[1] & 0x80) || !(p[2] & 0x80))) ||
          ((ie_len == 5) && ((p[1] & 0x80) || (p[2] & 0x80) ||
                         !(p[3] & 0x80))) ||
          (ie_len > 5) ||
          !(p[ie_len - 1] & 0x80))
            return "Invalid DLCI IE";

      dlci = ((p[0] & 0x3F) << 4) | ((p[1] & 0x78) >> 3);
      if (ie_len == 4)
            dlci = (dlci << 6) | ((p[2] & 0x7E) >> 1);
      else if (ie_len == 5)
            dlci = (dlci << 13) | (p[2] & 0x7F) | ((p[3] & 0x7E) >> 1);

      snprintf(buffer, buffer_len, "DLCI %d: status %s%s", dlci,
             p[ie_len - 1] & 0x8 ? "New, " : "",
             p[ie_len - 1] & 0x2 ? "Active" : "Inactive");

      return buffer;
}


static void
lmi_print(const u_char *p, u_int length)
{
      const u_char *ptemp = p;
      const char *decode_str;
      char temp_str[255];
      struct common_ie_header *ie_p;
      int is_ansi = 0;

      if (length < 9) { /* shortest: Q.933a LINK VERIFY */
            printf("[|lmi]");
            return;
      }

      if (p[2] == MSG_ANSI_LOCKING_SHIFT)
            is_ansi = 1;
    
      /* printing out header part */
      printf(is_ansi ? "ANSI" : "CCITT");
      if (p[0])
            printf(" Call Ref: %02x!", p[0]);

      switch(p[1]) {

      case MSG_TYPE_STATUS:
            printf(" STATUS REPLY\n");
            break;

      case MSG_TYPE_STATUS_ENQ:
            printf(" STATUS ENQUIRY\n");
            break;

      default:
            printf(" UNKNOWN MSG Type %02x\n", p[1]);
            break;
      }

      if (length < (u_int)(2 - is_ansi)) {
            printf("[|lmi]");
            return;
      }
      length -= 2 - is_ansi;
      ptemp += 2 + is_ansi;
      
      /* Loop through the rest of IE */
      while (length > 0) {
            ie_p = (struct common_ie_header *)ptemp;
            if (length < sizeof(struct common_ie_header) ||
                length < sizeof(struct common_ie_header) + ie_p->ie_len) {
                  printf("[|lmi]");
                  return;
            }

            if ((is_ansi && ie_p->ie_id == ANSI_REPORT_TYPE_IE) ||
                (!is_ansi && ie_p->ie_id == CCITT_REPORT_TYPE_IE)) {
                  switch(ptemp[2]) {

                  case FULL_STATUS:
                        decode_str = "FULL STATUS";
                        break;

                  case LINK_VERIFY:
                        decode_str = "LINK VERIFY";
                        break;

                  case ASYNC_PVC:
                        decode_str = "Async PVC Status";
                        break;

                  default:
                        decode_str = "Reserved Value";
                        break;
                  }
            } else if ((is_ansi && (ie_p->ie_id == ANSI_LINK_VERIFY_IE_91 ||
                                ie_p->ie_id == ANSI_LINK_VERIFY_IE)) ||
                    (!is_ansi && ie_p->ie_id == CCITT_LINK_VERIFY_IE)) {
                  snprintf(temp_str, sizeof(temp_str),
                       "TX Seq: %3d, RX Seq: %3d",
                       ptemp[2], ptemp[3]);
                  decode_str = temp_str;
            } else if ((is_ansi && ie_p->ie_id == ANSI_PVC_STATUS_IE) ||
                     (!is_ansi && ie_p->ie_id == CCITT_PVC_STATUS_IE)) {
                  decode_str = parse_dlci_ie(ptemp + 2, ie_p->ie_len,
                                       temp_str, sizeof(temp_str));
            } else
                  decode_str = "Non-decoded Value";             

            printf("\t\tIE: %02X Len: %d, %s\n",
                   ie_p->ie_id, ie_p->ie_len, decode_str);
            length = length - ie_p->ie_len - 2;
            ptemp = ptemp + ie_p->ie_len + 2;
      }
}

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