/*

* 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

*/

#define NETDISSECT_REWORKED

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>

#include <string.h>

#include "interface.h"

#include "addrtoname.h"

#include "extract.h" /* must come after interface.h */

#include "ip.h"

#ifdef INET6

#include "ip6.h"

#endif

#include "ipproto.h"

/**

* 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 {

} UNALIGNED;

/**

* 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 {

} UNALIGNED;

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

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

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

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

/**

* struct dccp_hdr_request - Conection initiation request header

*

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

*/

struct dccp_hdr_request {

u_int32_t dccph_req_service;

} UNALIGNED;

/**

* struct dccp_hdr_response - Conection 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 {

u_int8_t dccph_resp_ack[8]; /* always 8 bytes */

u_int32_t dccph_resp_service;

} UNALIGNED;

/**

* 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 {

} UNALIGNED;

enum dccp_pkt_type {

};

enum dccp_reset_codes {

};

static const char tstr[] = "[|dccp]";

static const char *dccp_reset_codes[] = {

"unspecified",

"closed",

"aborted",

"no_connection",

"packet_error",

"option_error",

"mandatory_error",

"connection_refused",

"bad_service_code",

"too_busy",

"bad_init_cookie",

"aggression_penalty",

};

static const char *dccp_feature_nums[] = {

"reserved",

"ccid",

"allow_short_seqno",

"sequence_window",

"ecn_incapable",

"ack_ratio",

"send_ack_vector",

"send_ndp_count",

"minimum checksum coverage",

"check data checksum",

};

static inline u_int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)

{

u_int cov;

if (DCCPH_CSCOV(dh) == 0)

return len;

cov = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(u_int32_t);

return (cov > len)? len : cov;

}

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

const struct dccp_hdr *dh, u_int len)

{

return nextproto4_cksum(ndo, ip, (const u_int8_t *)(void *)dh, len,

dccp_csum_coverage(dh, len), IPPROTO_DCCP);

}

#ifdef INET6

static int dccp6_cksum(const struct ip6_hdr *ip6, const struct dccp_hdr *dh, u_int len)

{

return nextproto6_cksum(ip6, (const u_int8_t *)(void *)dh, len,

dccp_csum_coverage(dh, len), IPPROTO_DCCP);

}

#endif

static const char *dccp_reset_code(u_int8_t code)

{

if (code >= __DCCP_RESET_CODE_LAST)

return "invalid";

return dccp_reset_codes[code];

}

static u_int64_t dccp_seqno(const u_char *bp)

{

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

u_int64_t seqno;

if (DCCPH_X(dh) != 0) {

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

seqno = EXTRACT_48BITS(dhx->dccph_seq);

} else {

seqno = EXTRACT_24BITS(dh->dccph_seq);

}

return seqno;

}

static inline unsigned int dccp_basic_hdr_len(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(dh);

u_int64_t ackno;

if (DCCPH_X(dh) != 0) {

ND_TCHECK2(*ackp, 8);

ackno = EXTRACT_48BITS(ackp + 2);

} else {

ND_TCHECK2(*ackp, 4);

ackno = EXTRACT_24BITS(ackp + 1);

}

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

trunc:

return;

}

static 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 - lenght of ip packet

*/

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

u_int len)

{

const struct dccp_hdr *dh;

const struct ip *ip;

#ifdef INET6

const struct ip6_hdr *ip6;

#endif

const u_char *cp;

u_short sport, dport;

u_int hlen;

u_int fixed_hdrlen;

dh = (const struct dccp_hdr *)bp;

ip = (struct ip *)data2;

#ifdef INET6

if (IP_V(ip) == 6)

ip6 = (const struct ip6_hdr *)data2;

else

ip6 = NULL;

#endif /*INET6*/

/* make sure we have enough data to look at the X bit */

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

if (cp > ndo->ndo_snapend) {

ND_PRINT((ndo, "[Invalid packet|dccp]"));

return;

}

if (len < sizeof(struct dccp_hdr)) {

ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",

len - (u_int)sizeof(struct dccp_hdr)));

return;

}

/* get the length of the generic header */

fixed_hdrlen = dccp_basic_hdr_len(dh);

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_TCHECK2(*dh, fixed_hdrlen);

sport = EXTRACT_16BITS(&dh->dccph_sport);

dport = EXTRACT_16BITS(&dh->dccph_dport);

hlen = dh->dccph_doff * 4;

#ifdef INET6

if (ip6) {

ND_PRINT((ndo, "%s.%d > %s.%d: ",

ip6addr_string(ndo, &ip6->ip6_src), sport,

ip6addr_string(ndo, &ip6->ip6_dst), dport));

} else

#endif /*INET6*/

{

ND_PRINT((ndo, "%s.%d > %s.%d: ",

ipaddr_string(ndo, &ip->ip_src), sport,

ipaddr_string(ndo, &ip->ip_dst), dport));

}

if (ndo->ndo_qflag) {

ND_PRINT((ndo, " %d", len - hlen));

if (hlen > len) {

ND_PRINT((ndo, "dccp [bad hdr length %u - too long, > %u]",

hlen, len));

}

return;

}

/* other variables in generic header */

if (ndo->ndo_vflag) {

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

}

/* checksum calculation */

if (ndo->ndo_vflag && ND_TTEST2(bp[0], len)) {

u_int16_t sum = 0, dccp_sum;

dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);

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

if (IP_V(ip) == 4)

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

#ifdef INET6

else if (IP_V(ip) == 6)

sum = dccp6_cksum(ip6, dh, len);

#endif

if (sum != 0)

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

else

ND_PRINT((ndo, "(correct), "));

}

switch (DCCPH_TYPE(dh)) {

case DCCP_PKT_REQUEST: {

struct dccp_hdr_request *dhr =

(struct dccp_hdr_request *)(bp + fixed_hdrlen);

fixed_hdrlen += 4;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp request - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_TCHECK(*dhr);

ND_PRINT((ndo, "request (service=%d) ",

EXTRACT_32BITS(&dhr->dccph_req_service)));

break;

}

case DCCP_PKT_RESPONSE: {

struct dccp_hdr_response *dhr =

(struct dccp_hdr_response *)(bp + fixed_hdrlen);

fixed_hdrlen += 12;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp response - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_TCHECK(*dhr);

ND_PRINT((ndo, "response (service=%d) ",

EXTRACT_32BITS(&dhr->dccph_resp_service)));

break;

}

case DCCP_PKT_DATA:

ND_PRINT((ndo, "data "));

break;

case DCCP_PKT_ACK: {

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp ack - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "ack "));

break;

}

case DCCP_PKT_DATAACK: {

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp dataack - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "dataack "));

break;

}

case DCCP_PKT_CLOSEREQ:

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp closereq - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "closereq "));

break;

case DCCP_PKT_CLOSE:

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp close - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "close "));

break;

case DCCP_PKT_RESET: {

struct dccp_hdr_reset *dhr =

(struct dccp_hdr_reset *)(bp + fixed_hdrlen);

fixed_hdrlen += 12;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp reset - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_TCHECK(*dhr);

ND_PRINT((ndo, "reset (code=%s) ",

dccp_reset_code(dhr->dccph_reset_code)));

break;

}

case DCCP_PKT_SYNC:

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp sync - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "sync "));

break;

case DCCP_PKT_SYNCACK:

fixed_hdrlen += 8;

if (len < fixed_hdrlen) {

ND_PRINT((ndo, "truncated-dccp syncack - %u bytes missing!",

len - fixed_hdrlen));

return;

}

ND_PRINT((ndo, "syncack "));

break;

default:

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

/* process options */

if (hlen > fixed_hdrlen){

const u_char *cp;

u_int optlen;

cp = bp + fixed_hdrlen;

ND_PRINT((ndo, " <"));

hlen -= fixed_hdrlen;

while(1){

optlen = dccp_print_option(ndo, cp, hlen);

if (!optlen)

break;

if (hlen <= optlen)

break;

hlen -= optlen;

cp += optlen;

ND_PRINT((ndo, ", "));

}

ND_PRINT((ndo, ">"));

}

return;

trunc:

ND_PRINT((ndo, "%s", tstr));

return;

}

static const struct tok dccp_option_values[] = {

{ 0, "nop" },

{ 1, "mandatory" },

{ 2, "slowreceiver" },

{ 32, "change_l" },

{ 33, "confirm_l" },

{ 34, "change_r" },

{ 35, "confirm_r" },

{ 36, "initcookie" },

{ 37, "ndp_count" },

{ 38, "ack_vector0" },

{ 39, "ack_vector1" },

{ 40, "data_dropped" },

{ 41, "timestamp" },

{ 42, "timestamp_echo" },

{ 43, "elapsed_time" },

{ 44, "data_checksum" },

{ 0, NULL }

};

static int dccp_print_option(netdissect_options *ndo, const u_char *option, u_int hlen)

{

u_int8_t optlen, i;

ND_TCHECK(*option);

if (*option >= 32) {

ND_TCHECK(*(option+1));

optlen = *(option +1);

if (optlen < 2) {

if (*option >= 128)

ND_PRINT((ndo, "CCID option %u optlen too short", *option));

else

ND_PRINT((ndo, "%s optlen too short",

tok2str(dccp_option_values, "Option %u", *option)));

return 0;

}

} else

optlen = 1;

if (hlen < optlen) {

if (*option >= 128)

ND_PRINT((ndo, "CCID option %u optlen goes past header length",

*option));

else

ND_PRINT((ndo, "%s optlen goes past header length",

tok2str(dccp_option_values, "Option %u", *option)));

return 0;

}

ND_TCHECK2(*option, optlen);

if (*option >= 128) {

ND_PRINT((ndo, "CCID option %d", *option));

switch (optlen) {

case 4:

ND_PRINT((ndo, " %u", EXTRACT_16BITS(option + 2)));

break;

case 6:

ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));

break;

default:

break;

}

} else {

ND_PRINT((ndo, "%s", tok2str(dccp_option_values, "Option %u", *option)));

switch (*option) {

case 32:

case 33:

case 34:

case 35:

if (optlen < 3) {

ND_PRINT((ndo, " optlen too short"));

return optlen;

}

if (*(option + 2) < 10){

ND_PRINT((ndo, " %s", dccp_feature_nums[*(option + 2)]));

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

ND_PRINT((ndo, " %d", *(option + 3 + i)));

}

break;

case 36:

if (optlen > 2) {

ND_PRINT((ndo, " 0x"));

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

ND_PRINT((ndo, "%02x", *(option + 2 + i)));

}

break;

case 37:

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

ND_PRINT((ndo, " %d", *(option + 2 + i)));

break;

case 38:

if (optlen > 2) {

ND_PRINT((ndo, " 0x"));

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

ND_PRINT((ndo, "%02x", *(option + 2 + i)));

}

break;

case 39:

if (optlen > 2) {

ND_PRINT((ndo, " 0x"));

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

ND_PRINT((ndo, "%02x", *(option + 2 + i)));

}

break;

case 40:

if (optlen > 2) {

ND_PRINT((ndo, " 0x"));

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

ND_PRINT((ndo, "%02x", *(option + 2 + i)));

}

break;

case 41:

if (optlen == 4)

ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));

else

ND_PRINT((ndo, " optlen != 4"));

break;

case 42:

if (optlen == 4)

ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));

else

ND_PRINT((ndo, " optlen != 4"));

break;

case 43:

if (optlen == 6)

ND_PRINT((ndo, " %u", EXTRACT_32BITS(option + 2)));

else if (optlen == 4)

ND_PRINT((ndo, " %u", EXTRACT_16BITS(option + 2)));

else

ND_PRINT((ndo, " optlen != 4 or 6"));

break;

case 44:

if (optlen > 2) {

ND_PRINT((ndo, " "));

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

ND_PRINT((ndo, "%02x", *(option + 2 + i)));

}

break;

}

}

return optlen;

trunc:

ND_PRINT((ndo, "%s", tstr));

return 0;

}