/*

* Copyright (C) Arnaldo Carvalho de Melo 2004

* Copyright (C) Ian McDonald 2005

* Copyright (C) Yoshifumi Nishida 2005

*

* This software may be distributed either under the terms of the

* BSD-style license that accompanies tcpdump or the GNU GPL version 2

*/

/* \summary: Datagram Congestion Control Protocol (DCCP) printer */

/* specification: RFC 4340 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include "netdissect-stdinc.h"

#define ND_LONGJMP_FROM_TCHECK

#include "netdissect.h"

#include "addrtoname.h"

#include "extract.h"

#include "ip.h"

#include "ip6.h"

#include "ipproto.h"

/* RFC4340: Datagram Congestion Control Protocol (DCCP) */

/**

* struct dccp_hdr - generic part of DCCP packet header, with a 24-bit

* sequence number

*

* @dccph_sport - Relevant port on the endpoint that sent this packet

* @dccph_dport - Relevant port on the other endpoint

* @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words

* @dccph_ccval - Used by the HC-Sender CCID

* @dccph_cscov - Parts of the packet that are covered by the Checksum field

* @dccph_checksum - Internet checksum, depends on dccph_cscov

* @dccph_x - 0 = 24 bit sequence number, 1 = 48

* @dccph_type - packet type, see DCCP_PKT_ prefixed macros

* @dccph_seq - 24-bit sequence number

*/

struct dccp_hdr {

};

/**

* struct dccp_hdr_ext - generic part of DCCP packet header, with a 48-bit

* sequence number

*

* @dccph_sport - Relevant port on the endpoint that sent this packet

* @dccph_dport - Relevant port on the other endpoint

* @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words

* @dccph_ccval - Used by the HC-Sender CCID

* @dccph_cscov - Parts of the packet that are covered by the Checksum field

* @dccph_checksum - Internet checksum, depends on dccph_cscov

* @dccph_x - 0 = 24 bit sequence number, 1 = 48

* @dccph_type - packet type, see DCCP_PKT_ prefixed macros

* @dccph_seq - 48-bit sequence number

*/

struct dccp_hdr_ext {

};

#define DCCPH_CCVAL(dh) ((GET_U_1((dh)->dccph_ccval_cscov) >> 4) & 0xF)

#define DCCPH_CSCOV(dh) (GET_U_1((dh)->dccph_ccval_cscov) & 0xF)

#define DCCPH_X(dh) (GET_U_1((dh)->dccph_xtr) & 1)

#define DCCPH_TYPE(dh) ((GET_U_1((dh)->dccph_xtr) >> 1) & 0xF)

/**

* struct dccp_hdr_request - Connection initiation request header

*

* @dccph_req_service - Service to which the client app wants to connect

*/

struct dccp_hdr_request {

nd_uint32_t dccph_req_service;

};

/**

* struct dccp_hdr_response - Connection initiation response header

*

* @dccph_resp_ack - 48 bit ack number, contains GSR

* @dccph_resp_service - Echoes the Service Code on a received DCCP-Request

*/

struct dccp_hdr_response {

nd_uint64_t dccph_resp_ack; /* always 8 bytes, first 2 reserved */

nd_uint32_t dccph_resp_service;

};

/**

* struct dccp_hdr_reset - Unconditionally shut down a connection

*

* @dccph_resp_ack - 48 bit ack number

* @dccph_reset_service - Echoes the Service Code on a received DCCP-Request

*/

struct dccp_hdr_reset {

};

enum dccp_pkt_type {

};

static const struct tok dccp_pkt_type_str[] = {

{ DCCP_PKT_REQUEST, "DCCP-Request" },

{ DCCP_PKT_RESPONSE, "DCCP-Response" },

{ DCCP_PKT_DATA, "DCCP-Data" },

{ DCCP_PKT_ACK, "DCCP-Ack" },

{ DCCP_PKT_DATAACK, "DCCP-DataAck" },

{ DCCP_PKT_CLOSEREQ, "DCCP-CloseReq" },

{ DCCP_PKT_CLOSE, "DCCP-Close" },

{ DCCP_PKT_RESET, "DCCP-Reset" },

{ DCCP_PKT_SYNC, "DCCP-Sync" },

{ DCCP_PKT_SYNCACK, "DCCP-SyncAck" },

{ 0, NULL}

};

enum dccp_reset_codes {

};

static const struct tok dccp_reset_code_str[] = {

{ DCCP_RESET_CODE_UNSPECIFIED, "unspecified" },

{ DCCP_RESET_CODE_CLOSED, "closed" },

{ DCCP_RESET_CODE_ABORTED, "aborted" },

{ DCCP_RESET_CODE_NO_CONNECTION, "no_connection" },

{ DCCP_RESET_CODE_PACKET_ERROR, "packet_error" },

{ DCCP_RESET_CODE_OPTION_ERROR, "option_error" },

{ DCCP_RESET_CODE_MANDATORY_ERROR, "mandatory_error" },

{ DCCP_RESET_CODE_CONNECTION_REFUSED, "connection_refused" },

{ DCCP_RESET_CODE_BAD_SERVICE_CODE, "bad_service_code" },

{ DCCP_RESET_CODE_TOO_BUSY, "too_busy" },

{ DCCP_RESET_CODE_BAD_INIT_COOKIE, "bad_init_cookie" },

{ DCCP_RESET_CODE_AGGRESSION_PENALTY, "aggression_penalty" },

{ 0, NULL }

};

static const struct tok dccp_feature_num_str[] = {

{ 0, "reserved" },

{ 1, "ccid" },

{ 2, "allow_short_seqno" },

{ 3, "sequence_window" },

{ 4, "ecn_incapable" },

{ 5, "ack_ratio" },

{ 6, "send_ack_vector" },

{ 7, "send_ndp_count" },

{ 8, "minimum_checksum_coverage" },

{ 9, "check_data_checksum" },

{ 0, NULL }

};

static u_int

dccp_csum_coverage(netdissect_options *ndo,

const struct dccp_hdr *dh, u_int len)

{

u_int cov;

if (DCCPH_CSCOV(dh) == 0)

return len;

cov = (GET_U_1(dh->dccph_doff) + DCCPH_CSCOV(dh) - 1) * sizeof(uint32_t);

return (cov > len)? len : cov;

}

static uint16_t dccp_cksum(netdissect_options *ndo, const struct ip *ip,

const struct dccp_hdr *dh, u_int len)

{

return nextproto4_cksum(ndo, ip, (const uint8_t *)(const void *)dh, len,

dccp_csum_coverage(ndo, dh, len), IPPROTO_DCCP);

}

static uint16_t dccp6_cksum(netdissect_options *ndo, const struct ip6_hdr *ip6,

const struct dccp_hdr *dh, u_int len)

{

return nextproto6_cksum(ndo, ip6, (const uint8_t *)(const void *)dh, len,

dccp_csum_coverage(ndo, dh, len), IPPROTO_DCCP);

}

static uint64_t

dccp_seqno(netdissect_options *ndo, const u_char *bp)

{

const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;

uint64_t seqno;

if (DCCPH_X(dh) != 0) {

const struct dccp_hdr_ext *dhx = (const struct dccp_hdr_ext *)bp;

seqno = GET_BE_U_6(dhx->dccph_seq);

} else {

seqno = GET_BE_U_3(dh->dccph_seq);

}

return seqno;

}

static unsigned int

dccp_basic_hdr_len(netdissect_options *ndo, const struct dccp_hdr *dh)

{

return DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : sizeof(struct dccp_hdr);

}

static void dccp_print_ack_no(netdissect_options *ndo, const u_char *bp)

{

const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;

const u_char *ackp = bp + dccp_basic_hdr_len(ndo, dh);

uint64_t ackno;

if (DCCPH_X(dh) != 0) {

ackno = GET_BE_U_6(ackp + 2);

} else {

ackno = GET_BE_U_3(ackp + 1);

}

ND_PRINT("(ack=%" PRIu64 ") ", ackno);

}

static u_int dccp_print_option(netdissect_options *, const u_char *, u_int);

/**

* dccp_print - show dccp packet

* @bp - beginning of dccp packet

* @data2 - beginning of enclosing

* @len - length of ip packet

*/

void

dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,

u_int length)

{

const struct dccp_hdr *dh;

const struct ip *ip;

const struct ip6_hdr *ip6;

const u_char *cp;

u_short sport, dport;

u_int hlen;

u_int fixed_hdrlen;

uint8_t dccph_type;

ndo->ndo_protocol = "dccp";

dh = (const struct dccp_hdr *)bp;

ip = (const struct ip *)data2;

if (IP_V(ip) == 6)

ip6 = (const struct ip6_hdr *)data2;

else

ip6 = NULL;

cp = (const u_char *)(dh + 1);

ND_ICHECK_ZU(length, <, sizeof(struct dccp_hdr));

/* get the length of the generic header */

fixed_hdrlen = dccp_basic_hdr_len(ndo, dh);

ND_ICHECK_U(length, <, fixed_hdrlen);

ND_TCHECK_LEN(dh, fixed_hdrlen);

sport = GET_BE_U_2(dh->dccph_sport);

dport = GET_BE_U_2(dh->dccph_dport);

hlen = GET_U_1(dh->dccph_doff) * 4;

if (ip6) {

ND_PRINT("%s.%u > %s.%u: ",

GET_IP6ADDR_STRING(ip6->ip6_src), sport,

GET_IP6ADDR_STRING(ip6->ip6_dst), dport);

} else {

ND_PRINT("%s.%u > %s.%u: ",

GET_IPADDR_STRING(ip->ip_src), sport,

GET_IPADDR_STRING(ip->ip_dst), dport);

}

nd_print_protocol_caps(ndo);

if (ndo->ndo_qflag) {

ND_ICHECK_U(length, <, hlen);

ND_PRINT(" %u", length - hlen);

return;

}

/* other variables in generic header */

if (ndo->ndo_vflag) {

ND_PRINT(" (CCVal %u, CsCov %u", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));

/* checksum calculation */

if (ND_TTEST_LEN(bp, length)) {

uint16_t sum = 0, dccp_sum;

dccp_sum = GET_BE_U_2(dh->dccph_checksum);

ND_PRINT(", cksum 0x%04x ", dccp_sum);

if (IP_V(ip) == 4)

sum = dccp_cksum(ndo, ip, dh, length);

else if (IP_V(ip) == 6)

sum = dccp6_cksum(ndo, ip6, dh, length);

if (sum != 0)

ND_PRINT("(incorrect -> 0x%04x)",in_cksum_shouldbe(dccp_sum, sum));

else

ND_PRINT("(correct)");

}

ND_PRINT(")");

}

dccph_type = DCCPH_TYPE(dh);

ND_PRINT(" %s ", tok2str(dccp_pkt_type_str, "packet-type-%u",

dccph_type));

switch (dccph_type) {

case DCCP_PKT_REQUEST: {

const struct dccp_hdr_request *dhr =

(const struct dccp_hdr_request *)(bp + fixed_hdrlen);

fixed_hdrlen += 4;

ND_ICHECK_U(length, <, fixed_hdrlen);

ND_PRINT("(service=%u) ", GET_BE_U_4(dhr->dccph_req_service));

break;

}

case DCCP_PKT_RESPONSE: {

const struct dccp_hdr_response *dhr =

(const struct dccp_hdr_response *)(bp + fixed_hdrlen);

fixed_hdrlen += 12;

ND_ICHECK_U(length, <, fixed_hdrlen);

ND_PRINT("(service=%u) ", GET_BE_U_4(dhr->dccph_resp_service));

break;

}

case DCCP_PKT_DATA:

break;

case DCCP_PKT_ACK: {

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

}

case DCCP_PKT_DATAACK: {

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

}

case DCCP_PKT_CLOSEREQ:

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

case DCCP_PKT_CLOSE:

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

case DCCP_PKT_RESET: {

const struct dccp_hdr_reset *dhr =

(const struct dccp_hdr_reset *)(bp + fixed_hdrlen);

fixed_hdrlen += 12;

ND_ICHECK_U(length, <, fixed_hdrlen);

ND_TCHECK_SIZE(dhr);

ND_PRINT("(code=%s) ", tok2str(dccp_reset_code_str,

"reset-code-%u (invalid)", GET_U_1(dhr->dccph_reset_code)));

break;

}

case DCCP_PKT_SYNC:

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

case DCCP_PKT_SYNCACK:

fixed_hdrlen += 8;

ND_ICHECK_U(length, <, fixed_hdrlen);

break;

default:

goto invalid;

break;

}

if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&

(DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))

dccp_print_ack_no(ndo, bp);

if (ndo->ndo_vflag < 2)

return;

ND_PRINT("seq %" PRIu64, dccp_seqno(ndo, bp));

/* process options */

if (hlen > fixed_hdrlen){

u_int optlen;

cp = bp + fixed_hdrlen;

ND_PRINT(" <");

hlen -= fixed_hdrlen;

while(1){

optlen = dccp_print_option(ndo, cp, hlen);

if (!optlen)

goto invalid;

if (hlen <= optlen)

break;

hlen -= optlen;

cp += optlen;

ND_PRINT(", ");

}

ND_PRINT(">");

}

return;

invalid:

nd_print_invalid(ndo);

}

enum dccp_option_type {

};

static const struct tok dccp_option_values[] = {

{ DCCP_OPTION_PADDING, "nop" },

{ DCCP_OPTION_MANDATORY, "mandatory" },

{ DCCP_OPTION_SLOW_RECEIVER, "slowreceiver" },

{ DCCP_OPTION_CHANGE_L, "change_l" },

{ DCCP_OPTION_CONFIRM_L, "confirm_l" },

{ DCCP_OPTION_CHANGE_R, "change_r" },

{ DCCP_OPTION_CONFIRM_R, "confirm_r" },

{ DCCP_OPTION_INIT_COOKIE, "initcookie" },

{ DCCP_OPTION_NDP_COUNT, "ndp_count" },

{ DCCP_OPTION_ACK_VECTOR_NONCE_0, "ack_vector0" },

{ DCCP_OPTION_ACK_VECTOR_NONCE_1, "ack_vector1" },

{ DCCP_OPTION_DATA_DROPPED, "data_dropped" },

{ DCCP_OPTION_TIMESTAMP, "timestamp" },

{ DCCP_OPTION_TIMESTAMP_ECHO, "timestamp_echo" },

{ DCCP_OPTION_ELAPSED_TIME, "elapsed_time" },

{ DCCP_OPTION_DATA_CHECKSUM, "data_checksum" },

{ 0, NULL }

};

static u_int

dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)

{

uint8_t option, optlen, i;

option = GET_U_1(bp);

if (option >= 128)

ND_PRINT("CCID option %u", option);

else

ND_PRINT("%s",

tok2str(dccp_option_values, "option-type-%u", option));

if (option >= 32) {

optlen = GET_U_1(bp + 1);

ND_ICHECK_U(optlen, <, 2);

} else

optlen = 1;

ND_ICHECKMSG_U("remaining length", hlen, <, optlen);

if (option >= 128) {

switch (optlen) {

case 4:

ND_PRINT(" %u", GET_BE_U_2(bp + 2));

break;

case 6:

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

break;

default:

ND_PRINT(" 0x");

for (i = 0; i < optlen - 2; i++)

ND_PRINT("%02x", GET_U_1(bp + 2 + i));

break;

}

} else {

switch (option) {

case DCCP_OPTION_PADDING:

case DCCP_OPTION_MANDATORY:

case DCCP_OPTION_SLOW_RECEIVER:

ND_TCHECK_1(bp);

break;

case DCCP_OPTION_CHANGE_L:

case DCCP_OPTION_CHANGE_R:

ND_ICHECK_U(optlen, <, 4);

ND_PRINT(" %s", tok2str(dccp_feature_num_str,

"feature-number-%u (invalid)", GET_U_1(bp + 2)));

for (i = 0; i < optlen - 3; i++)

ND_PRINT(" %u", GET_U_1(bp + 3 + i));

break;

case DCCP_OPTION_CONFIRM_L:

case DCCP_OPTION_CONFIRM_R:

ND_ICHECK_U(optlen, <, 3);

ND_PRINT(" %s", tok2str(dccp_feature_num_str,

"feature-number-%u (invalid)", GET_U_1(bp + 2)));

for (i = 0; i < optlen - 3; i++)

ND_PRINT(" %u", GET_U_1(bp + 3 + i));

break;

case DCCP_OPTION_INIT_COOKIE:

ND_ICHECK_U(optlen, <, 3);

ND_PRINT(" 0x");

for (i = 0; i < optlen - 2; i++)

ND_PRINT("%02x", GET_U_1(bp + 2 + i));

break;

case DCCP_OPTION_NDP_COUNT:

ND_ICHECK_U(optlen, <, 3);

ND_ICHECK_U(optlen, >, 8);

for (i = 0; i < optlen - 2; i++)

ND_PRINT(" %u", GET_U_1(bp + 2 + i));

break;

case DCCP_OPTION_ACK_VECTOR_NONCE_0:

case DCCP_OPTION_ACK_VECTOR_NONCE_1:

ND_ICHECK_U(optlen, <, 3);

ND_PRINT(" 0x");

for (i = 0; i < optlen - 2; i++)

ND_PRINT("%02x", GET_U_1(bp + 2 + i));

break;

case DCCP_OPTION_DATA_DROPPED:

ND_ICHECK_U(optlen, <, 3);

ND_PRINT(" 0x");

for (i = 0; i < optlen - 2; i++)

ND_PRINT("%02x", GET_U_1(bp + 2 + i));

break;

case DCCP_OPTION_TIMESTAMP:

/*

* 13.1. Timestamp Option

*

* +--------+--------+--------+--------+--------+--------+

* |00101001|00000110| Timestamp Value |

* +--------+--------+--------+--------+--------+--------+

* Type=41 Length=6

*/

ND_ICHECK_U(optlen, !=, 6);

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

break;

case DCCP_OPTION_TIMESTAMP_ECHO:

/*

* 13.3. Timestamp Echo Option

*

* +--------+--------+--------+--------+--------+--------+

* |00101010|00000110| Timestamp Echo |

* +--------+--------+--------+--------+--------+--------+

* Type=42 Len=6

*

* +--------+--------+------- ... -------+--------+--------+

* |00101010|00001000| Timestamp Echo | Elapsed Time |

* +--------+--------+------- ... -------+--------+--------+

* Type=42 Len=8 (4 bytes)

*

* +--------+--------+------- ... -------+------- ... -------+

* |00101010|00001010| Timestamp Echo | Elapsed Time |

* +--------+--------+------- ... -------+------- ... -------+

* Type=42 Len=10 (4 bytes) (4 bytes)

*/

switch (optlen) {

case 6:

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

break;

case 8:

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

ND_PRINT(" (elapsed time %u)",

GET_BE_U_2(bp + 6));

break;

case 10:

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

ND_PRINT(" (elapsed time %u)",

GET_BE_U_4(bp + 6));

break;

default:

ND_PRINT(" [optlen != 6 or 8 or 10]");

goto invalid;

break;

}

break;

case DCCP_OPTION_ELAPSED_TIME:

switch (optlen) {

case 4:

ND_PRINT(" %u", GET_BE_U_2(bp + 2));

break;

case 6:

ND_PRINT(" %u", GET_BE_U_4(bp + 2));

break;

default:

ND_PRINT(" [optlen != 4 or 6]");

goto invalid;

}

break;

case DCCP_OPTION_DATA_CHECKSUM:

ND_ICHECK_U(optlen, !=, 6);

ND_PRINT(" 0x");

for (i = 0; i < optlen - 2; i++)

ND_PRINT("%02x", GET_U_1(bp + 2 + i));

break;

default:

goto invalid;

}

}

return optlen;

invalid:

return 0;

}