* Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996

/*
* 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.
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-fr.c,v 1.12 2024/09/02 16:15:31 christos Exp $");
#endif

/* \summary: Frame Relay printer */

#include <config.h>

#include "netdissect-stdinc.h"

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

#include "netdissect.h"
#include "addrtoname.h"
#include "ethertype.h"
#include "llc.h"
#include "nlpid.h"
#include "extract.h"

static void frf15_print(netdissect_options *ndo, const u_char *, u_int);

/*
* the frame relay header has a variable length
*
* the EA bit determines if there is another byte
* in the header
*
* minimum header length is 2 bytes
* maximum header length is 4 bytes
*
* 7 6 5 4 3 2 1 0
* +----+----+----+----+----+----+----+----+
* | DLCI (6 bits) | CR | EA |
* +----+----+----+----+----+----+----+----+
* | DLCI (4 bits) |FECN|BECN| DE | EA |
* +----+----+----+----+----+----+----+----+
* | DLCI (7 bits) | EA |
* +----+----+----+----+----+----+----+----+
* | DLCI (6 bits) |SDLC| EA |
* +----+----+----+----+----+----+----+----+
*/

#define FR_EA_BIT 0x01

#define FR_CR_BIT 0x02000000
#define FR_DE_BIT 0x00020000
#define FR_BECN_BIT 0x00040000
#define FR_FECN_BIT 0x00080000
#define FR_SDLC_BIT 0x00000002

static const struct tok fr_header_flag_values[] = {
{ FR_CR_BIT, "C!" },
{ FR_DE_BIT, "DE" },
{ FR_BECN_BIT, "BECN" },
{ FR_FECN_BIT, "FECN" },
{ FR_SDLC_BIT, "sdlcore" },
{ 0, NULL }
};

/* FRF.15 / FRF.16 */
#define MFR_B_BIT 0x80
#define MFR_E_BIT 0x40
#define MFR_C_BIT 0x20
#define MFR_BEC_MASK (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
#define MFR_CTRL_FRAME (MFR_B_BIT | MFR_E_BIT | MFR_C_BIT)
#define MFR_FRAG_FRAME (MFR_B_BIT | MFR_E_BIT )

static const struct tok frf_flag_values[] = {
{ MFR_B_BIT, "Begin" },
{ MFR_E_BIT, "End" },
{ MFR_C_BIT, "Control" },
{ 0, NULL }
};

/* Finds out Q.922 address length, DLCI and flags. Returns 1 on success,
* 0 on invalid address, -1 on truncated packet
* save the flags dep. on address length
*/
static int parse_q922_header(netdissect_options *ndo,
const u_char *p, u_int *dlci,
u_int *addr_len, uint32_t *flags, u_int length)
{
if (!ND_TTEST_1(p) || length < 1)
return -1;
if ((GET_U_1(p) & FR_EA_BIT))
return 0;

if (!ND_TTEST_1(p + 1) || length < 2)
return -1;
*addr_len = 2;
*dlci = ((GET_U_1(p) & 0xFC) << 2) | ((GET_U_1(p + 1) & 0xF0) >> 4);

*flags = ((GET_U_1(p) & 0x02) << 24) | /* CR flag */
((GET_U_1(p + 1) & 0x0e) << 16); /* FECN,BECN,DE flags */

if (GET_U_1(p + 1) & FR_EA_BIT)
return 1; /* 2-byte Q.922 address */

p += 2;
length -= 2;
if (!ND_TTEST_1(p) || length < 1)
return -1;
(*addr_len)++; /* 3- or 4-byte Q.922 address */
if ((GET_U_1(p) & FR_EA_BIT) == 0) {
*dlci = (*dlci << 7) | (GET_U_1(p) >> 1);
(*addr_len)++; /* 4-byte Q.922 address */
p++;
length--;
}

if (!ND_TTEST_1(p) || length < 1)
return -1;
if ((GET_U_1(p) & FR_EA_BIT) == 0)
return 0; /* more than 4 bytes of Q.922 address? */

*flags = *flags | (GET_U_1(p) & 0x02); /* SDLC flag */

*dlci = (*dlci << 6) | (GET_U_1(p) >> 2);

return 1;
}

const char *
q922_string(netdissect_options *ndo, const u_char *p, u_int length)
{

static u_int dlci, addr_len;
static uint32_t flags;
static char buffer[sizeof("parse_q922_header() returned XXXXXXXXXXX")];
int ret;
memset(buffer, 0, sizeof(buffer));

ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
if (ret == 1) {
snprintf(buffer, sizeof(buffer), "DLCI %u", dlci);
return buffer;
} else if (ret == 0) {
return "<Invalid DLCI>";
} else if (ret == -1) {
return "<Truncated>";
} else {
snprintf(buffer, sizeof(buffer), "parse_q922_header() returned %d", ret);
return buffer;
}
}

/* 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 void
fr_hdr_print(netdissect_options *ndo, int length, u_int addr_len,
u_int dlci, uint32_t flags, uint16_t nlpid)
{
if (ndo->ndo_qflag) {
ND_PRINT("Q.922, DLCI %u, length %u: ",
dlci,
length);
} else {
if (nlpid <= 0xff) /* if its smaller than 256 then its a NLPID */
ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], NLPID %s (0x%02x), length %u: ",
addr_len,
dlci,
bittok2str(fr_header_flag_values, "none", flags),
tok2str(nlpid_values,"unknown", nlpid),
nlpid,
length);
else /* must be an ethertype */
ND_PRINT("Q.922, hdr-len %u, DLCI %u, Flags [%s], cisco-ethertype %s (0x%04x), length %u: ",
addr_len,
dlci,
bittok2str(fr_header_flag_values, "none", flags),
tok2str(ethertype_values, "unknown", nlpid),
nlpid,
length);
}
}

/* Frame Relay */
void
fr_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
u_int length = h->len;
u_int caplen = h->caplen;

ndo->ndo_protocol = "fr";
if (caplen < 4) { /* minimum frame header length */
nd_print_trunc(ndo);
ndo->ndo_ll_hdr_len += caplen;
return;
}

ndo->ndo_ll_hdr_len += fr_print(ndo, p, length);
}

u_int
fr_print(netdissect_options *ndo,
const u_char *p, u_int length)
{
int ret;
uint16_t extracted_ethertype;
u_int dlci;
u_int addr_len;
uint16_t nlpid;
u_int hdr_len;
uint32_t flags;

ndo->ndo_protocol = "fr";
ret = parse_q922_header(ndo, p, &dlci, &addr_len, &flags, length);
if (ret == -1)
goto trunc;
if (ret == 0) {
ND_PRINT("Q.922, invalid address");
return 0;
}

ND_TCHECK_1(p + addr_len);
if (length < addr_len + 1)
goto trunc;

if (GET_U_1(p + addr_len) != LLC_UI && dlci != 0) {
/*
* Let's figure out if we have Cisco-style encapsulation,
* with an Ethernet type (Cisco HDLC type?) following the
* address.
*/
if (!ND_TTEST_2(p + addr_len) || length < addr_len + 2) {
/* no Ethertype */
ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
} else {
extracted_ethertype = GET_BE_U_2(p + addr_len);

if (ndo->ndo_eflag)
fr_hdr_print(ndo, length, addr_len, dlci,
flags, extracted_ethertype);

if (ethertype_print(ndo, extracted_ethertype,
p+addr_len+ETHERTYPE_LEN,
length-addr_len-ETHERTYPE_LEN,
ND_BYTES_AVAILABLE_AFTER(p)-addr_len-ETHERTYPE_LEN,
NULL, NULL) == 0)
/* ether_type not known, probably it wasn't one */
ND_PRINT("UI %02x! ", GET_U_1(p + addr_len));
else
return addr_len + 2;
}
}

ND_TCHECK_1(p + addr_len + 1);
if (length < addr_len + 2)
goto trunc;

if (GET_U_1(p + addr_len + 1) == 0) {
/*
* Assume a pad byte after the control (UI) byte.
* A pad byte should only be used with 3-byte Q.922.
*/
if (addr_len != 3)
ND_PRINT("Pad! ");
hdr_len = addr_len + 1 /* UI */ + 1 /* pad */ + 1 /* NLPID */;
} else {
/*
* Not a pad byte.
* A pad byte should be used with 3-byte Q.922.
*/
if (addr_len == 3)
ND_PRINT("No pad! ");
hdr_len = addr_len + 1 /* UI */ + 1 /* NLPID */;
}

ND_TCHECK_1(p + hdr_len - 1);
if (length < hdr_len)
goto trunc;
nlpid = GET_U_1(p + hdr_len - 1);

if (ndo->ndo_eflag)
fr_hdr_print(ndo, length, addr_len, dlci, flags, nlpid);
p += hdr_len;
length -= hdr_len;

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

case NLPID_IP6:
ip6_print(ndo, p, length);
break;

case NLPID_CLNP:
case NLPID_ESIS:
case NLPID_ISIS:
isoclns_print(ndo, p - 1, length + 1); /* OSI printers need the NLPID field */
break;

case NLPID_SNAP:
if (snap_print(ndo, p, length, ND_BYTES_AVAILABLE_AFTER(p), NULL, NULL, 0) == 0) {
/* ether_type not known, print raw packet */
if (!ndo->ndo_eflag)
fr_hdr_print(ndo, length + hdr_len, hdr_len,
dlci, flags, nlpid);
if (!ndo->ndo_suppress_default_print)
ND_DEFAULTPRINT(p - hdr_len, length + hdr_len);
}
break;

case NLPID_Q933:
q933_print(ndo, p, length);
break;

case NLPID_MFR:
frf15_print(ndo, p, length);
break;

case NLPID_PPP:
ppp_print(ndo, p, length);
break;

default:
if (!ndo->ndo_eflag)
fr_hdr_print(ndo, length + hdr_len, addr_len,
dlci, flags, nlpid);
if (!ndo->ndo_xflag)
ND_DEFAULTPRINT(p, length);
}

return hdr_len;

trunc:
nd_print_trunc(ndo);
return 0;

}

/* Multi Link Frame Relay (FRF.16) */
void
mfr_if_print(netdissect_options *ndo,
const struct pcap_pkthdr *h, const u_char *p)
{
u_int length = h->len;
u_int caplen = h->caplen;

ndo->ndo_protocol = "mfr";
if (caplen < 2) { /* minimum frame header length */
nd_print_trunc(ndo);
ndo->ndo_ll_hdr_len += caplen;
return;
}

ndo->ndo_ll_hdr_len += mfr_print(ndo, p, length);
}

#define MFR_CTRL_MSG_ADD_LINK 1
#define MFR_CTRL_MSG_ADD_LINK_ACK 2
#define MFR_CTRL_MSG_ADD_LINK_REJ 3
#define MFR_CTRL_MSG_HELLO 4
#define MFR_CTRL_MSG_HELLO_ACK 5
#define MFR_CTRL_MSG_REMOVE_LINK 6
#define MFR_CTRL_MSG_REMOVE_LINK_ACK 7

static const struct tok mfr_ctrl_msg_values[] = {
{ MFR_CTRL_MSG_ADD_LINK, "Add Link" },
{ MFR_CTRL_MSG_ADD_LINK_ACK, "Add Link ACK" },
{ MFR_CTRL_MSG_ADD_LINK_REJ, "Add Link Reject" },
{ MFR_CTRL_MSG_HELLO, "Hello" },
{ MFR_CTRL_MSG_HELLO_ACK, "Hello ACK" },
{ MFR_CTRL_MSG_REMOVE_LINK, "Remove Link" },
{ MFR_CTRL_MSG_REMOVE_LINK_ACK, "Remove Link ACK" },
{ 0, NULL }
};

#define MFR_CTRL_IE_BUNDLE_ID 1
#define MFR_CTRL_IE_LINK_ID 2
#define MFR_CTRL_IE_MAGIC_NUM 3
#define MFR_CTRL_IE_TIMESTAMP 5
#define MFR_CTRL_IE_VENDOR_EXT 6
#define MFR_CTRL_IE_CAUSE 7

static const struct tok mfr_ctrl_ie_values[] = {
{ MFR_CTRL_IE_BUNDLE_ID, "Bundle ID"},
{ MFR_CTRL_IE_LINK_ID, "Link ID"},
{ MFR_CTRL_IE_MAGIC_NUM, "Magic Number"},
{ MFR_CTRL_IE_TIMESTAMP, "Timestamp"},
{ MFR_CTRL_IE_VENDOR_EXT, "Vendor Extension"},
{ MFR_CTRL_IE_CAUSE, "Cause"},
{ 0, NULL }
};

#define MFR_ID_STRING_MAXLEN 50

struct ie_tlv_header_t {
uint8_t ie_type;
uint8_t ie_len;
};

u_int
mfr_print(netdissect_options *ndo,
const u_char *p, u_int length)
{
u_int tlen,idx,hdr_len = 0;
uint16_t sequence_num;
uint8_t ie_type,ie_len;
const uint8_t *tptr;

/*
* FRF.16 Link Integrity Control Frame
*
* 7 6 5 4 3 2 1 0
* +----+----+----+----+----+----+----+----+
* | B | E | C=1| 0 0 0 0 | EA |
* +----+----+----+----+----+----+----+----+
* | 0 0 0 0 0 0 0 0 |
* +----+----+----+----+----+----+----+----+
* | message type |
* +----+----+----+----+----+----+----+----+
*/

ndo->ndo_protocol = "mfr";

if (length < 4) { /* minimum frame header length */
ND_PRINT("[length %u < 4]", length);
nd_print_invalid(ndo);
return length;
}
ND_TCHECK_4(p);

if ((GET_U_1(p) & MFR_BEC_MASK) == MFR_CTRL_FRAME && GET_U_1(p + 1) == 0) {
ND_PRINT("FRF.16 Control, Flags [%s], %s, length %u",
bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)),
tok2str(mfr_ctrl_msg_values,"Unknown Message (0x%02x)",GET_U_1(p + 2)),
length);
tptr = p + 3;
tlen = length -3;
hdr_len = 3;

if (!ndo->ndo_vflag)
return hdr_len;

while (tlen>sizeof(struct ie_tlv_header_t)) {
ND_TCHECK_LEN(tptr, sizeof(struct ie_tlv_header_t));
ie_type=GET_U_1(tptr);
ie_len=GET_U_1(tptr + 1);

ND_PRINT("\n\tIE %s (%u), length %u: ",
tok2str(mfr_ctrl_ie_values,"Unknown",ie_type),
ie_type,
ie_len);

/* infinite loop check */
if (ie_type == 0 || ie_len <= sizeof(struct ie_tlv_header_t))
return hdr_len;

ND_TCHECK_LEN(tptr, ie_len);
tptr+=sizeof(struct ie_tlv_header_t);
/* tlv len includes header */
ie_len-=sizeof(struct ie_tlv_header_t);
tlen-=sizeof(struct ie_tlv_header_t);

switch (ie_type) {

case MFR_CTRL_IE_MAGIC_NUM:
/* FRF.16.1 Section 3.4.3 Magic Number Information Element */
if (ie_len != 4) {
ND_PRINT("[IE data length %d != 4]", ie_len);
nd_print_invalid(ndo);
break;
}
ND_PRINT("0x%08x", GET_BE_U_4(tptr));
break;

case MFR_CTRL_IE_BUNDLE_ID: /* same message format */
case MFR_CTRL_IE_LINK_ID:
for (idx = 0; idx < ie_len && idx < MFR_ID_STRING_MAXLEN; idx++) {
if (GET_U_1(tptr + idx) != 0) /* don't print null termination */
fn_print_char(ndo, GET_U_1(tptr + idx));
else
break;
}
break;

case MFR_CTRL_IE_TIMESTAMP:
/*
* FRF.16.1 Section 3.4.4 Timestamp Information Element
*
* The maximum length is 14 octets. Format is implementation
* specific.
*/
if (ie_len > 14) {
ND_PRINT("[Timestamp IE length %d > 14]", ie_len);
nd_print_invalid(ndo);
break;
}
/* fall through and hexdump */
ND_FALL_THROUGH;

/*
* FIXME those are the defined IEs that lack a decoder
* you are welcome to contribute code ;-)
*/

case MFR_CTRL_IE_VENDOR_EXT:
case MFR_CTRL_IE_CAUSE:

default:
if (ndo->ndo_vflag <= 1)
print_unknown_data(ndo, tptr, "\n\t ", ie_len);
break;
}

/* do we want to see a hexdump of the IE ? */
if (ndo->ndo_vflag > 1 )
print_unknown_data(ndo, tptr, "\n\t ", ie_len);

tlen-=ie_len;
tptr+=ie_len;
}
return hdr_len;
}
/*
* FRF.16 Fragmentation Frame
*
* 7 6 5 4 3 2 1 0
* +----+----+----+----+----+----+----+----+
* | B | E | C=0|seq. (high 4 bits) | EA |
* +----+----+----+----+----+----+----+----+
* | sequence (low 8 bits) |
* +----+----+----+----+----+----+----+----+
* | DLCI (6 bits) | CR | EA |
* +----+----+----+----+----+----+----+----+
* | DLCI (4 bits) |FECN|BECN| DE | EA |
* +----+----+----+----+----+----+----+----+
*/

sequence_num = (GET_U_1(p)&0x1e)<<7 | GET_U_1(p + 1);
/* whole packet or first fragment ? */
if ((GET_U_1(p) & MFR_BEC_MASK) == MFR_FRAG_FRAME ||
(GET_U_1(p) & MFR_BEC_MASK) == MFR_B_BIT) {
ND_PRINT("FRF.16 Frag, seq %u, Flags [%s], ",
sequence_num,
bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)));
hdr_len = 2;
fr_print(ndo, p+hdr_len,length-hdr_len);
return hdr_len;
}

/* must be a middle or the last fragment */
ND_PRINT("FRF.16 Frag, seq %u, Flags [%s]",
sequence_num,
bittok2str(frf_flag_values,"none",(GET_U_1(p) & MFR_BEC_MASK)));
print_unknown_data(ndo, p, "\n\t", length);

return hdr_len;

trunc:
nd_print_trunc(ndo);
return length;
}

/* an NLPID of 0xb1 indicates a 2-byte
* FRF.15 header
*
* 7 6 5 4 3 2 1 0
* +----+----+----+----+----+----+----+----+
* ~ Q.922 header ~
* +----+----+----+----+----+----+----+----+
* | NLPID (8 bits) | NLPID=0xb1
* +----+----+----+----+----+----+----+----+
* | B | E | C |seq. (high 4 bits) | R |
* +----+----+----+----+----+----+----+----+
* | sequence (low 8 bits) |
* +----+----+----+----+----+----+----+----+
*/

#define FR_FRF15_FRAGTYPE 0x01

static void
frf15_print(netdissect_options *ndo,
const u_char *p, u_int length)
{
uint16_t sequence_num, flags;

if (length < 2)
goto trunc;

flags = GET_U_1(p)&MFR_BEC_MASK;
sequence_num = (GET_U_1(p)&0x1e)<<7 | GET_U_1(p + 1);

ND_PRINT("FRF.15, seq 0x%03x, Flags [%s],%s Fragmentation, length %u",
sequence_num,
bittok2str(frf_flag_values,"none",flags),
GET_U_1(p)&FR_FRF15_FRAGTYPE ? "Interface" : "End-to-End",
length);

/* TODO:
* depending on all permutations of the B, E and C bit
* dig as deep as we can - e.g. on the first (B) fragment
* there is enough payload to print the IP header
* on non (B) fragments it depends if the fragmentation
* model is end-to-end or interface based whether we want to print
* another Q.922 header
*/
return;

trunc:
nd_print_trunc(ndo);
}

/*
* 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

static const struct tok fr_q933_msg_values[] = {
{ MSG_TYPE_ESC_TO_NATIONAL, "ESC to National" },
{ MSG_TYPE_ALERT, "Alert" },
{ MSG_TYPE_CALL_PROCEEDING, "Call proceeding" },
{ MSG_TYPE_CONNECT, "Connect" },
{ MSG_TYPE_CONNECT_ACK, "Connect ACK" },
{ MSG_TYPE_PROGRESS, "Progress" },
{ MSG_TYPE_SETUP, "Setup" },
{ MSG_TYPE_DISCONNECT, "Disconnect" },
{ MSG_TYPE_RELEASE, "Release" },
{ MSG_TYPE_RELEASE_COMPLETE, "Release Complete" },
{ MSG_TYPE_RESTART, "Restart" },
{ MSG_TYPE_RESTART_ACK, "Restart ACK" },
{ MSG_TYPE_STATUS, "Status Reply" },
{ MSG_TYPE_STATUS_ENQ, "Status Enquiry" },
{ 0, NULL }
};

#define IE_IS_SINGLE_OCTET(iecode) ((iecode) & 0x80)
#define IE_IS_SHIFT(iecode) (((iecode) & 0xF0) == 0x90)
#define IE_SHIFT_IS_NON_LOCKING(iecode) ((iecode) & 0x08)
#define IE_SHIFT_IS_LOCKING(iecode) (!(IE_SHIFT_IS_NON_LOCKING(iecode)))
#define IE_SHIFT_CODESET(iecode) ((iecode) & 0x07)

#define FR_LMI_ANSI_REPORT_TYPE_IE 0x01
#define FR_LMI_ANSI_LINK_VERIFY_IE_91 0x19 /* details? */
#define FR_LMI_ANSI_LINK_VERIFY_IE 0x03
#define FR_LMI_ANSI_PVC_STATUS_IE 0x07

#define FR_LMI_CCITT_REPORT_TYPE_IE 0x51
#define FR_LMI_CCITT_LINK_VERIFY_IE 0x53
#define FR_LMI_CCITT_PVC_STATUS_IE 0x57

static const struct tok fr_q933_ie_values_codeset_0_5[] = {
{ FR_LMI_ANSI_REPORT_TYPE_IE, "ANSI Report Type" },
{ FR_LMI_ANSI_LINK_VERIFY_IE_91, "ANSI Link Verify" },
{ FR_LMI_ANSI_LINK_VERIFY_IE, "ANSI Link Verify" },
{ FR_LMI_ANSI_PVC_STATUS_IE, "ANSI PVC Status" },
{ FR_LMI_CCITT_REPORT_TYPE_IE, "CCITT Report Type" },
{ FR_LMI_CCITT_LINK_VERIFY_IE, "CCITT Link Verify" },
{ FR_LMI_CCITT_PVC_STATUS_IE, "CCITT PVC Status" },
{ 0, NULL }
};

#define FR_LMI_REPORT_TYPE_IE_FULL_STATUS 0
#define FR_LMI_REPORT_TYPE_IE_LINK_VERIFY 1
#define FR_LMI_REPORT_TYPE_IE_ASYNC_PVC 2

static const struct tok fr_lmi_report_type_ie_values[] = {
{ FR_LMI_REPORT_TYPE_IE_FULL_STATUS, "Full Status" },
{ FR_LMI_REPORT_TYPE_IE_LINK_VERIFY, "Link verify" },
{ FR_LMI_REPORT_TYPE_IE_ASYNC_PVC, "Async PVC Status" },
{ 0, NULL }
};

/* array of 16 codesets - currently we only support codepage 0 and 5 */
static const struct tok *fr_q933_ie_codesets[] = {
fr_q933_ie_values_codeset_0_5,
NULL,
NULL,
NULL,
NULL,
fr_q933_ie_values_codeset_0_5,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL
};

static int fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
u_int ielength, const u_char *p);

typedef int (*codeset_pr_func_t)(netdissect_options *, u_int iecode,
u_int ielength, const u_char *p);

/* array of 16 codesets - currently we only support codepage 0 and 5 */
static const codeset_pr_func_t fr_q933_print_ie_codeset[] = {
fr_q933_print_ie_codeset_0_5,
NULL,
NULL,
NULL,
NULL,
fr_q933_print_ie_codeset_0_5,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL
};

/*
* ITU-T Q.933.
*
* p points to octet 2, the octet containing the length of the
* call reference value, so p[n] is octet n+2 ("octet X" is as
* used in Q.931/Q.933).
*
* XXX - actually used both for Q.931 and Q.933.
*/
void
q933_print(netdissect_options *ndo,
const u_char *p, u_int length)
{
u_int olen;
u_int call_ref_length, i;
uint8_t call_ref[15]; /* maximum length - length field is 4 bits */
u_int msgtype;
u_int iecode;
u_int ielength;
u_int codeset = 0;
u_int is_ansi = 0;
u_int ie_is_known;
u_int non_locking_shift;
u_int unshift_codeset;

ndo->ndo_protocol = "q.933";
ND_PRINT("%s", ndo->ndo_eflag ? "" : "Q.933");

if (length == 0 || !ND_TTEST_1(p)) {
if (!ndo->ndo_eflag)
ND_PRINT(", ");
ND_PRINT("length %u", length);
goto trunc;
}

/*
* Get the length of the call reference value.
*/
olen = length; /* preserve the original length for display */
call_ref_length = GET_U_1(p) & 0x0f;
p++;
length--;

/*
* Get the call reference value.
*/
for (i = 0; i < call_ref_length; i++) {
if (length == 0 || !ND_TTEST_1(p)) {
if (!ndo->ndo_eflag)
ND_PRINT(", ");
ND_PRINT("length %u", olen);
goto trunc;
}
call_ref[i] = GET_U_1(p);
p++;
length--;
}

/*
* Get the message type.
*/
if (length == 0 || !ND_TTEST_1(p)) {
if (!ndo->ndo_eflag)
ND_PRINT(", ");
ND_PRINT("length %u", olen);
goto trunc;
}
msgtype = GET_U_1(p);
p++;
length--;

/*
* Peek ahead to see if we start with a shift.
*/
non_locking_shift = 0;
unshift_codeset = codeset;
if (length != 0) {
if (!ND_TTEST_1(p)) {
if (!ndo->ndo_eflag)
ND_PRINT(", ");
ND_PRINT("length %u", olen);
goto trunc;
}
iecode = GET_U_1(p);
if (IE_IS_SHIFT(iecode)) {
/*
* It's a shift. Skip over it.
*/
p++;
length--;

/*
* Get the codeset.
*/
codeset = IE_SHIFT_CODESET(iecode);

/*
* If it's a locking shift to codeset 5,
* mark this as ANSI. (XXX - 5 is actually
* for national variants in general, not
* the US variant in particular, but maybe
* this is more American exceptionalism. :-))
*/
if (IE_SHIFT_IS_LOCKING(iecode)) {
/*
* It's a locking shift.
*/
if (codeset == 5) {
/*
* It's a locking shift to
* codeset 5, so this is
* T1.617 Annex D.
*/
is_ansi = 1;
}
} else {
/*
* It's a non-locking shift.
* Remember the current codeset, so we
* can revert to it after the next IE.
*/
non_locking_shift = 1;
unshift_codeset = 0;
}
}
}

/* printing out header part */
if (!ndo->ndo_eflag)
ND_PRINT(", ");
ND_PRINT("%s, codeset %u", is_ansi ? "ANSI" : "CCITT", codeset);

if (call_ref_length != 0) {
if (call_ref_length > 1 || GET_U_1(p) != 0) {
/*
* Not a dummy call reference.
*/
ND_PRINT(", Call Ref: 0x");
for (i = 0; i < call_ref_length; i++)
ND_PRINT("%02x", call_ref[i]);
}
}
if (ndo->ndo_vflag) {
ND_PRINT(", %s (0x%02x), length %u",
tok2str(fr_q933_msg_values,
"unknown message", msgtype),
msgtype,
olen);
} else {
ND_PRINT(", %s",
tok2str(fr_q933_msg_values,
"unknown message 0x%02x", msgtype));
}

/* Loop through the rest of the IEs */
while (length != 0) {
/*
* What's the state of any non-locking shifts?
*/
if (non_locking_shift == 1) {
/*
* There's a non-locking shift in effect for
* this IE. Count it, so we reset the codeset
* before the next IE.
*/
non_locking_shift = 2;
} else if (non_locking_shift == 2) {
/*
* Unshift.
*/
codeset = unshift_codeset;
non_locking_shift = 0;
}

/*
* Get the first octet of the IE.
*/
if (!ND_TTEST_1(p)) {
if (!ndo->ndo_vflag) {
ND_PRINT(", length %u", olen);
}
goto trunc;
}
iecode = GET_U_1(p);
p++;
length--;

/* Single-octet IE? */
if (IE_IS_SINGLE_OCTET(iecode)) {
/*
* Yes. Is it a shift?
*/
if (IE_IS_SHIFT(iecode)) {
/*
* Yes. Is it locking?
*/
if (IE_SHIFT_IS_LOCKING(iecode)) {
/*
* Yes.
*/
non_locking_shift = 0;
} else {
/*
* No. Remember the current
* codeset, so we can revert
* to it after the next IE.
*/
non_locking_shift = 1;
unshift_codeset = codeset;
}

/*
* Get the codeset.
*/
codeset = IE_SHIFT_CODESET(iecode);
}
} else {
/*
* No. Get the IE length.
*/
if (length == 0 || !ND_TTEST_1(p)) {
if (!ndo->ndo_vflag) {
ND_PRINT(", length %u", olen);
}
goto trunc;
}
ielength = GET_U_1(p);
p++;
length--;

/* lets do the full IE parsing only in verbose mode
* however some IEs (DLCI Status, Link Verify)
* are also interesting in non-verbose mode */
if (ndo->ndo_vflag) {
ND_PRINT("\n\t%s IE (0x%02x), length %u: ",
tok2str(fr_q933_ie_codesets[codeset],
"unknown", iecode),
iecode,
ielength);
}

/* sanity checks */
if (iecode == 0 || ielength == 0) {
return;
}
if (length < ielength || !ND_TTEST_LEN(p, ielength)) {
if (!ndo->ndo_vflag) {
ND_PRINT(", length %u", olen);
}
goto trunc;
}

ie_is_known = 0;
if (fr_q933_print_ie_codeset[codeset] != NULL) {
ie_is_known = fr_q933_print_ie_codeset[codeset](ndo, iecode, ielength, p);
}

if (ie_is_known) {
/*
* Known IE; do we want to see a hexdump
* of it?
*/
if (ndo->ndo_vflag > 1) {
/* Yes. */
print_unknown_data(ndo, p, "\n\t ", ielength);
}
} else {
/*
* Unknown IE; if we're printing verbosely,
* print its content in hex.
*/
if (ndo->ndo_vflag >= 1) {
print_unknown_data(ndo, p, "\n\t", ielength);
}
}

length -= ielength;
p += ielength;
}
}
if (!ndo->ndo_vflag) {
ND_PRINT(", length %u", olen);
}
return;

trunc:
nd_print_trunc(ndo);
}

static int
fr_q933_print_ie_codeset_0_5(netdissect_options *ndo, u_int iecode,
u_int ielength, const u_char *p)
{
u_int dlci;

switch (iecode) {

case FR_LMI_ANSI_REPORT_TYPE_IE: /* fall through */
case FR_LMI_CCITT_REPORT_TYPE_IE:
if (ielength < 1) {
if (!ndo->ndo_vflag) {
ND_PRINT(", ");
}
ND_PRINT("Invalid REPORT TYPE IE");
return 1;
}
if (ndo->ndo_vflag) {
ND_PRINT("%s (%u)",
tok2str(fr_lmi_report_type_ie_values,"unknown",GET_U_1(p)),
GET_U_1(p));
}
return 1;

case FR_LMI_ANSI_LINK_VERIFY_IE: /* fall through */
case FR_LMI_CCITT_LINK_VERIFY_IE:
case FR_LMI_ANSI_LINK_VERIFY_IE_91:
if (!ndo->ndo_vflag) {
ND_PRINT(", ");
}
if (ielength < 2) {
ND_PRINT("Invalid LINK VERIFY IE");
return 1;
}
ND_PRINT("TX Seq: %3d, RX Seq: %3d", GET_U_1(p), GET_U_1(p + 1));
return 1;

case FR_LMI_ANSI_PVC_STATUS_IE: /* fall through */
case FR_LMI_CCITT_PVC_STATUS_IE:
if (!ndo->ndo_vflag) {
ND_PRINT(", ");
}
/* now parse the DLCI information element. */
if ((ielength < 3) ||
(GET_U_1(p) & 0x80) ||
((ielength == 3) && !(GET_U_1(p + 1) & 0x80)) ||
((ielength == 4) &&
((GET_U_1(p + 1) & 0x80) || !(GET_U_1(p + 2) & 0x80))) ||
((ielength == 5) &&
((GET_U_1(p + 1) & 0x80) || (GET_U_1(p + 2) & 0x80) ||
!(GET_U_1(p + 3) & 0x80))) ||
(ielength > 5) ||
!(GET_U_1(p + ielength - 1) & 0x80)) {
ND_PRINT("Invalid DLCI in PVC STATUS IE");
return 1;
}

dlci = ((GET_U_1(p) & 0x3F) << 4) | ((GET_U_1(p + 1) & 0x78) >> 3);
if (ielength == 4) {
dlci = (dlci << 6) | ((GET_U_1(p + 2) & 0x7E) >> 1);
} else if (ielength == 5) {
dlci = (dlci << 13) | (GET_U_1(p + 2) & 0x7F) | ((GET_U_1(p + 3) & 0x7E) >> 1);
}

ND_PRINT("DLCI %u: status %s%s", dlci,
GET_U_1(p + ielength - 1) & 0x8 ? "New, " : "",
GET_U_1(p + ielength - 1) & 0x2 ? "Active" : "Inactive");
return 1;
}

return 0;
}