]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-dccp.c
CI: Add warning exemptions for Sun C (suncc-5.14) on Solaris 10
[tcpdump] / print-dccp.c
index 0d020d656aca75144fe29f676e43c6ec9f529f84..2ae46a971e7e49ac15a1ef72fa066ad2cc2e841f 100644 (file)
@@ -7,26 +7,27 @@
  * BSD-style license that accompanies tcpdump or the GNU GPL version 2
  */
 
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+/* \summary: Datagram Congestion Control Protocol (DCCP) printer */
 
-#include <tcpdump-stdinc.h>
+/* specification: RFC 4340 */
 
-#include <stdio.h>
-#include <string.h>
+#include <config.h>
 
-#include "interface.h"
+#include "netdissect-stdinc.h"
+
+#define ND_LONGJMP_FROM_TCHECK
+#include "netdissect.h"
 #include "addrtoname.h"
-#include "extract.h"                   /* must come after interface.h */
+#include "extract.h"
 #include "ip.h"
-#ifdef INET6
 #include "ip6.h"
-#endif
 #include "ipproto.h"
 
+/* RFC4340: Datagram Congestion Control Protocol (DCCP) */
+
 /**
- * struct dccp_hdr - generic part of DCCP packet header
+ * 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_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 - sequence number high or low order 24 bits, depends on dccph_x
+ * @dccph_seq - 24-bit sequence number
  */
 struct dccp_hdr {
-       u_int16_t       dccph_sport,
+       nd_uint16_t     dccph_sport,
                        dccph_dport;
-       u_int8_t        dccph_doff;
-       u_int8_t        dccph_ccval_cscov;
-       u_int16_t       dccph_checksum;
-       union {
-       u_int8_t        dccph_xtr;
-       u_int32_t       dccph_seq;
-       }               dccph_xtrs;
+       nd_uint8_t      dccph_doff;
+       nd_uint8_t      dccph_ccval_cscov;
+       nd_uint16_t     dccph_checksum;
+       nd_uint8_t      dccph_xtr;
+       nd_uint24_t     dccph_seq;
 };
 
-#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_xtrs.dccph_xtr & 1)
-#define DCCPH_TYPE(dh) (((dh)->dccph_xtrs.dccph_xtr >> 1) & 0xF)
-#define DCCPH_SEQ(dh)   (((dh)->dccph_xtrs.dccph_seq) >> 8)
-
 /**
- * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
+ * struct dccp_hdr_ext - generic part of DCCP packet header, with a 48-bit
+ * sequence number
  *
- * @dccph_seq_low - low 24 bits of a 48 bit seq packet
+ * @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 {
-       u_int32_t       dccph_seq_low;
+       nd_uint16_t     dccph_sport,
+                       dccph_dport;
+       nd_uint8_t      dccph_doff;
+       nd_uint8_t      dccph_ccval_cscov;
+       nd_uint16_t     dccph_checksum;
+       nd_uint8_t      dccph_xtr;
+       nd_uint8_t      reserved;
+       nd_uint48_t     dccph_seq;
 };
 
+#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 - Conection initiation request header
+ * struct dccp_hdr_request - Connection 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;
+       nd_uint32_t     dccph_req_service;
 };
 
 /**
- * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
+ * struct dccp_hdr_response - Connection initiation response header
  *
- * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
- * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
- */
-struct dccp_hdr_ack_bits {
-       u_int32_t       dccph_ra;
-       u_int32_t       dccph_ack_nr_low;
-};
-
-#define DCCPH_ACK(dh_ack)   ((dh_ack)->dccph_ra >> 8)
-
-/**
- * struct dccp_hdr_response - Conection initiation response header
- *
- * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
- * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
+ * @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 {
-       struct dccp_hdr_ack_bits        dccph_resp_ack;
-       u_int32_t                       dccph_resp_service;
+       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 {
-       struct dccp_hdr_ack_bits        dccph_reset_ack;
-       u_int8_t                        dccph_reset_code,
-                                       dccph_reset_data[3];
+       nd_uint64_t     dccph_reset_ack;        /* always 8 bytes, first 2 reserved */
+       nd_uint8_t      dccph_reset_code;
+       nd_uint8_t      dccph_reset_data1;
+       nd_uint8_t      dccph_reset_data2;
+       nd_uint8_t      dccph_reset_data3;
 };
 
 enum dccp_pkt_type {
@@ -121,8 +124,21 @@ enum dccp_pkt_type {
        DCCP_PKT_CLOSE,
        DCCP_PKT_RESET,
        DCCP_PKT_SYNC,
-       DCCP_PKT_SYNCACK,
-       DCCP_PKT_INVALID
+       DCCP_PKT_SYNCACK
+};
+
+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 {
@@ -138,438 +154,472 @@ enum dccp_reset_codes {
        DCCP_RESET_CODE_TOO_BUSY,
        DCCP_RESET_CODE_BAD_INIT_COOKIE,
        DCCP_RESET_CODE_AGGRESSION_PENALTY,
-       __DCCP_RESET_CODE_LAST
 };
 
-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 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 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 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 inline u_int dccp_csum_coverage(const struct dccp_hdr* dh, u_int len)
+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 = (dh->dccph_doff + DCCPH_CSCOV(dh) - 1) * sizeof(u_int32_t);
+       cov = (GET_U_1(dh->dccph_doff) + DCCPH_CSCOV(dh) - 1) * sizeof(uint32_t);
        return (cov > len)? len : cov;
 }
 
-static int dccp_cksum(const struct ip *ip,
+static uint16_t dccp_cksum(netdissect_options *ndo, const struct ip *ip,
        const struct dccp_hdr *dh, u_int len)
 {
-       return nextproto4_cksum(ip, (const u_int8_t *)(void *)dh, len,
-                               dccp_csum_coverage(dh, len), IPPROTO_DCCP);
+       return nextproto4_cksum(ndo, ip, (const uint8_t *)(const void *)dh, len,
+                               dccp_csum_coverage(ndo, 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,
-           dccp_csum_coverage(dh, len), IPPROTO_DCCP);
-}
-#endif
-
-static const char *dccp_reset_code(u_int8_t code)
+static uint16_t dccp6_cksum(netdissect_options *ndo, const struct ip6_hdr *ip6,
+       const struct dccp_hdr *dh, u_int len)
 {
-       if (code >= __DCCP_RESET_CODE_LAST)
-               return "invalid";
-       return dccp_reset_codes[code];
+       return nextproto6_cksum(ndo, ip6, (const uint8_t *)(const void *)dh, len,
+                               dccp_csum_coverage(ndo, dh, len), IPPROTO_DCCP);
 }
 
-static u_int64_t dccp_seqno(const struct dccp_hdr *dh)
+static uint64_t
+dccp_seqno(netdissect_options *ndo, const u_char *bp)
 {
-       u_int32_t seq_high = DCCPH_SEQ(dh);
-       u_int64_t seqno = EXTRACT_24BITS(&seq_high) & 0xFFFFFF;
+       const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
+       uint64_t seqno;
 
        if (DCCPH_X(dh) != 0) {
-               const struct dccp_hdr_ext *dhx = (void *)(dh + 1);
-               u_int32_t seq_low = dhx->dccph_seq_low;
-               seqno &= 0x00FFFF;  /* clear reserved field */
-               seqno = (seqno << 32) + EXTRACT_32BITS(&seq_low);
+               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 inline unsigned int dccp_basic_hdr_len(const struct dccp_hdr *dh)
+static unsigned int
+dccp_basic_hdr_len(netdissect_options *ndo, const struct dccp_hdr *dh)
 {
-       return sizeof(*dh) + (DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : 0);
+       return DCCPH_X(dh) ? sizeof(struct dccp_hdr_ext) : sizeof(struct dccp_hdr);
 }
 
-static void dccp_print_ack_no(const u_char *bp)
+static void dccp_print_ack_no(netdissect_options *ndo, const u_char *bp)
 {
        const struct dccp_hdr *dh = (const struct dccp_hdr *)bp;
-       const struct dccp_hdr_ack_bits *dh_ack =
-               (struct dccp_hdr_ack_bits *)(bp + dccp_basic_hdr_len(dh));
-       u_int32_t ack_high;
-       u_int64_t ackno;
-
-       TCHECK2(*dh_ack,4);
-       ack_high = DCCPH_ACK(dh_ack);
-       ackno = EXTRACT_24BITS(&ack_high) & 0xFFFFFF;
+       const u_char *ackp = bp + dccp_basic_hdr_len(ndo, dh);
+       uint64_t ackno;
 
        if (DCCPH_X(dh) != 0) {
-               u_int32_t ack_low;
-
-               TCHECK2(*dh_ack,8);
-               ack_low = dh_ack->dccph_ack_nr_low;
-
-               ackno &= 0x00FFFF;  /* clear reserved field */
-               ackno = (ackno << 32) + EXTRACT_32BITS(&ack_low);
+               ackno = GET_BE_U_6(ackp + 2);
+       } else {
+               ackno = GET_BE_U_3(ackp + 1);
        }
 
-       (void)printf("(ack=%" PRIu64 ") ", ackno);
-trunc:
-       return;
-}
-
-static inline unsigned int dccp_packet_hdr_len(const u_int8_t type)
-{
-       if (type == DCCP_PKT_DATA)
-               return 0;
-       if (type == DCCP_PKT_DATAACK    ||
-           type == DCCP_PKT_ACK        ||
-           type == DCCP_PKT_SYNC       ||
-           type == DCCP_PKT_SYNCACK    ||
-           type == DCCP_PKT_CLOSE      ||
-           type == DCCP_PKT_CLOSEREQ)
-               return sizeof(struct dccp_hdr_ack_bits);
-       if (type == DCCP_PKT_REQUEST)
-               return sizeof(struct dccp_hdr_request);
-       if (type == DCCP_PKT_RESPONSE)
-               return sizeof(struct dccp_hdr_response);
-       return sizeof(struct dccp_hdr_reset);
+       ND_PRINT("(ack=%" PRIu64 ") ", ackno);
 }
 
-static int dccp_print_option(const u_char *option);
+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 - lenght of ip packet
+ * @len - length of ip packet
  */
-void dccp_print(const u_char *bp, const u_char *data2, u_int len)
+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;
-#ifdef INET6
        const struct ip6_hdr *ip6;
-#endif
        const u_char *cp;
        u_short sport, dport;
        u_int hlen;
-       u_int extlen = 0;
+       u_int fixed_hdrlen;
+       uint8_t dccph_type;
 
+       ndo->ndo_protocol = "dccp";
        dh = (const struct dccp_hdr *)bp;
 
-       ip = (struct ip *)data2;
-#ifdef INET6
+       ip = (const struct ip *)data2;
        if (IP_V(ip) == 6)
                ip6 = (const struct ip6_hdr *)data2;
        else
                ip6 = NULL;
-#endif /*INET6*/
+
        cp = (const u_char *)(dh + 1);
-       if (cp > snapend) {
-               printf("[Invalid packet|dccp]");
-               return;
-       }
+       ND_ICHECK_ZU(length, <, sizeof(struct dccp_hdr));
 
-       if (len < sizeof(struct dccp_hdr)) {
-               printf("truncated-dccp - %ld bytes missing!",
-                            (long)len - sizeof(struct dccp_hdr));
-               return;
-       }
+       /* 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 = EXTRACT_16BITS(&dh->dccph_sport);
-       dport = EXTRACT_16BITS(&dh->dccph_dport);
-       hlen = dh->dccph_doff * 4;
+       sport = GET_BE_U_2(dh->dccph_sport);
+       dport = GET_BE_U_2(dh->dccph_dport);
+       hlen = GET_U_1(dh->dccph_doff) * 4;
 
-#ifdef INET6
        if (ip6) {
-               (void)printf("%s.%d > %s.%d: ",
-                            ip6addr_string(&ip6->ip6_src), sport,
-                            ip6addr_string(&ip6->ip6_dst), dport);
-       } else
-#endif /*INET6*/
-       {
-               (void)printf("%s.%d > %s.%d: ",
-                            ipaddr_string(&ip->ip_src), sport,
-                            ipaddr_string(&ip->ip_dst), dport);
+               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);
        }
-       fflush(stdout);
 
-       if (qflag) {
-               (void)printf(" %d", len - hlen);
-               if (hlen > len) {
-                       (void)printf("dccp [bad hdr length %u - too long, > %u]",
-                           hlen, len);
-               }
+       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 (vflag) {
-               (void)printf("CCVal %d, CsCov %d, ", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
-       }
-
-       /* checksum calculation */
-       if (vflag && TTEST2(bp[0], len)) {
-               u_int16_t sum = 0, dccp_sum;
-
-               dccp_sum = EXTRACT_16BITS(&dh->dccph_checksum);
-               (void)printf("cksum 0x%04x ", dccp_sum);
-               if (IP_V(ip) == 4)
-                       sum = dccp_cksum(ip, dh, len);
-#ifdef INET6
-               else if (IP_V(ip) == 6)
-                       sum = dccp6_cksum(ip6, dh, len);
-#endif
-               if (sum != 0)
-                       (void)printf("(incorrect -> 0x%04x), ",in_cksum_shouldbe(dccp_sum, sum));
-               else
-                       (void)printf("(correct), ");
+       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(")");
        }
 
-       switch (DCCPH_TYPE(dh)) {
+       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: {
-               struct dccp_hdr_request *dhr =
-                       (struct dccp_hdr_request *)(bp + dccp_basic_hdr_len(dh));
-               TCHECK(*dhr);
-               (void)printf("request (service=%d) ",
-                            EXTRACT_32BITS(&dhr->dccph_req_service));
-               extlen += 4;
+               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: {
-               struct dccp_hdr_response *dhr =
-                       (struct dccp_hdr_response *)(bp + dccp_basic_hdr_len(dh));
-               TCHECK(*dhr);
-               (void)printf("response (service=%d) ",
-                            EXTRACT_32BITS(&dhr->dccph_resp_service));
-               extlen += 12;
+               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:
-               (void)printf("data ");
                break;
        case DCCP_PKT_ACK: {
-               (void)printf("ack ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        }
        case DCCP_PKT_DATAACK: {
-               (void)printf("dataack ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        }
        case DCCP_PKT_CLOSEREQ:
-               (void)printf("closereq ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_CLOSE:
-               (void)printf("close ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_RESET: {
-               struct dccp_hdr_reset *dhr =
-                       (struct dccp_hdr_reset *)(bp + dccp_basic_hdr_len(dh));
-               TCHECK(*dhr);
-               (void)printf("reset (code=%s) ",
-                            dccp_reset_code(dhr->dccph_reset_code));
-               extlen += 12;
+               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:
-               (void)printf("sync ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_SYNCACK:
-               (void)printf("syncack ");
-               extlen += 8;
+               fixed_hdrlen += 8;
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        default:
-               (void)printf("invalid ");
-               break;
+               goto invalid;
        }
 
        if ((DCCPH_TYPE(dh) != DCCP_PKT_DATA) &&
                        (DCCPH_TYPE(dh) != DCCP_PKT_REQUEST))
-               dccp_print_ack_no(bp);
+               dccp_print_ack_no(ndo, bp);
 
-       if (vflag < 2)
+       if (ndo->ndo_vflag < 2)
                return;
 
-       (void)printf("seq %" PRIu64, dccp_seqno(dh));
+       ND_PRINT("seq %" PRIu64, dccp_seqno(ndo, bp));
 
        /* process options */
-       if (hlen > dccp_basic_hdr_len(dh) + extlen){
-               const u_char *cp;
+       if (hlen > fixed_hdrlen){
                u_int optlen;
-               cp = bp + dccp_basic_hdr_len(dh) + extlen;
-               printf(" <");
+               cp = bp + fixed_hdrlen;
+               ND_PRINT(" <");
 
-               hlen -= dccp_basic_hdr_len(dh) + extlen;
+               hlen -= fixed_hdrlen;
                while(1){
-                       TCHECK(*cp);
-                       optlen = dccp_print_option(cp);
-                       if (!optlen) goto trunc2;
-                       if (hlen <= optlen) break;
+                       optlen = dccp_print_option(ndo, cp, hlen);
+                       if (!optlen)
+                               goto invalid;
+                       if (hlen <= optlen)
+                               break;
                        hlen -= optlen;
                        cp += optlen;
-                       printf(", ");
+                       ND_PRINT(", ");
                }
-               printf(">");
+               ND_PRINT(">");
        }
        return;
-trunc:
-       printf("%s", tstr);
-trunc2:
-       return;
+invalid:
+       nd_print_invalid(ndo);
 }
 
-static int dccp_print_option(const u_char *option)
-{
-       u_int8_t optlen, i;
-
-       TCHECK(*option);
+enum dccp_option_type {
+       DCCP_OPTION_PADDING = 0,
+       DCCP_OPTION_MANDATORY = 1,
+       DCCP_OPTION_SLOW_RECEIVER = 2,
+       DCCP_OPTION_CHANGE_L = 32,
+       DCCP_OPTION_CONFIRM_L = 33,
+       DCCP_OPTION_CHANGE_R = 34,
+       DCCP_OPTION_CONFIRM_R = 35,
+       DCCP_OPTION_INIT_COOKIE = 36,
+       DCCP_OPTION_NDP_COUNT = 37,
+       DCCP_OPTION_ACK_VECTOR_NONCE_0 = 38,
+       DCCP_OPTION_ACK_VECTOR_NONCE_1 = 39,
+       DCCP_OPTION_DATA_DROPPED = 40,
+       DCCP_OPTION_TIMESTAMP = 41,
+       DCCP_OPTION_TIMESTAMP_ECHO = 42,
+       DCCP_OPTION_ELAPSED_TIME = 43,
+       DCCP_OPTION_DATA_CHECKSUM = 44
+};
 
-       if (*option >= 32) {
-               TCHECK(*(option+1));
-               optlen = *(option +1);
-               if (optlen < 2) {
-                       printf("Option %d optlen too short",*option);
-                       return 1;
-               }
-       } else optlen = 1;
+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 }
+};
 
-       TCHECK2(*option,optlen);
+static u_int
+dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)
+{
+       uint8_t option, optlen, i;
 
-       switch (*option){
-       case 0:
-               printf("nop");
-               break;
-       case 1:
-               printf("mandatory");
-               break;
-       case 2:
-               printf("slowreceiver");
-               break;
-       case 32:
-               printf("change_l");
-               if (*(option +2) < 10){
-                       printf(" %s", dccp_feature_nums[*(option +2)]);
-                       for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
-               }
-               break;
-       case 33:
-               printf("confirm_l");
-               if (*(option +2) < 10){
-                       printf(" %s", dccp_feature_nums[*(option +2)]);
-                       for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
-               }
-               break;
-       case 34:
-               printf("change_r");
-               if (*(option +2) < 10){
-                       printf(" %s", dccp_feature_nums[*(option +2)]);
-                       for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + i));
-               }
-               break;
-       case 35:
-               printf("confirm_r");
-               if (*(option +2) < 10){
-                       printf(" %s", dccp_feature_nums[*(option +2)]);
-                       for (i = 0; i < optlen -3; i ++) printf(" %d", *(option +3 + 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;
                }
-               break;
-       case 36:
-               printf("initcookie 0x");
-               for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
-               break;
-       case 37:
-               printf("ndp_count");
-               for (i = 0; i < optlen -2; i ++) printf(" %d", *(option +2 + i));
-               break;
-       case 38:
-               printf("ack_vector0 0x");
-               for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
-               break;
-       case 39:
-               printf("ack_vector1 0x");
-               for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
-               break;
-       case 40:
-               printf("data_dropped 0x");
-               for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
-               break;
-       case 41:
-               printf("timestamp %u", EXTRACT_32BITS(option + 2));
-               break;
-       case 42:
-               printf("timestamp_echo %u", EXTRACT_32BITS(option + 2));
-               break;
-       case 43:
-               printf("elapsed_time ");
-               if (optlen == 6)
-                       printf("%u", EXTRACT_32BITS(option + 2));
-               else
-                       printf("%u", EXTRACT_16BITS(option + 2));
-               break;
-       case 44:
-               printf("data_checksum ");
-               for (i = 0; i < optlen -2; i ++) printf("%02x", *(option +2 + i));
-               break;
-       default :
-               if (*option >= 128) {
-                       printf("CCID option %d",*option);
+       } 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 4:
-                                       printf(" %u", EXTRACT_16BITS(option + 2));
-                                       break;
-                               case 6:
-                                       printf(" %u", EXTRACT_32BITS(option + 2));
-                                       break;
-                               default:
-                                       break;
+                       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;
+               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;
                }
-
-               printf("unknown_opt %d", *option);
-               break;
        }
 
        return optlen;
-trunc:
-       printf("%s", tstr);
+invalid:
        return 0;
 }