]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-dhcp6.c
Update from current NetBSD version of ieee80211_radiotap.h.
[tcpdump] / print-dhcp6.c
index 3a003e68db9bb2bf78015b5def096d98772a8eee..73b7b383a595d5cbdbf44b95f4cac562ed46375f 100644 (file)
  * SUCH DAMAGE.
  */
 /*
- * draft-ietf-dhc-dhcpv6-26.txt
+ * RFC3315: DHCPv6
+ * supported DHCPv6 options: 
+ *  RFC3319,
+ *  RFC3633,
+ *  RFC3646,
+ *  draft-ietf-dhc-dhcpv6-opt-timeconfig-03.txt,
+ *  draft-ietf-dhc-lifetime-00.txt,
  */
 
 #ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-dhcp6.c,v 1.20 2002-06-15 02:49:54 itojun Exp $";
+static const char rcsid[] _U_ =
+    "@(#) $Header: /tcpdump/master/tcpdump/print-dhcp6.c,v 1.35 2004-07-06 22:16:03 guy Exp $";
 #endif
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <sys/param.h>
-#include <sys/time.h>
-#include <sys/socket.h>
+#include <tcpdump-stdinc.h>
 
-#include <netinet/in.h>
-
-#include <ctype.h>
 #include <stdio.h>
 #include <string.h>
-#include <arpa/inet.h>
 
 #include "interface.h"
 #include "addrtoname.h"
+#include "extract.h"
 
 /* lease duration */
 #define DHCP6_DURATITION_INFINITE 0xffffffff
@@ -71,7 +72,12 @@ static const char rcsid[] =
 #define DH6_RENEW      5
 #define DH6_REBIND     6
 #define DH6_REPLY      7
+#define DH6_RELEASE    8
+#define DH6_DECLINE    9
+#define DH6_RECONFIGURE        10
 #define DH6_INFORM_REQ 11
+#define DH6_RELAY_FORW 12
+#define DH6_RELAY_REPLY        13
 
 /* DHCP6 base packet format */
 struct dhcp6 {
@@ -80,62 +86,111 @@ struct dhcp6 {
                u_int32_t x;
        } dh6_msgtypexid;
        /* options follow */
-} __attribute__ ((__packed__));
+};
 #define dh6_msgtype    dh6_msgtypexid.m
 #define dh6_xid                dh6_msgtypexid.x
 #define DH6_XIDMASK    0x00ffffff
 
-/* option */
+/* DHCPv6 relay messages */
+struct dhcp6_relay {
+       u_int8_t dh6relay_msgtype;
+       u_int8_t dh6relay_hcnt;
+       u_int8_t dh6relay_linkaddr[16]; /* XXX: badly aligned */
+       u_int8_t dh6relay_peeraddr[16];
+       /* options follow */
+};
+
+/* options */
 #define DH6OPT_CLIENTID        1
 #define DH6OPT_SERVERID        2
-#define DH6OPT_IA 3
+#define DH6OPT_IA_NA 3
 #define DH6OPT_IA_TMP 4
 #define DH6OPT_IADDR 5
 #define DH6OPT_ORO 6
 #define DH6OPT_PREFERENCE 7
-#  define DH6OPT_PREF_UNDEF -1
 #  define DH6OPT_PREF_MAX 255
 #define DH6OPT_ELAPSED_TIME 8
-#define DH6OPT_CLIENT_MSG 9
-#define DH6OPT_SERVER_MSG 10
+#define DH6OPT_RELAY_MSG 9
+/*#define DH6OPT_SERVER_MSG 10 deprecated */
 #define DH6OPT_AUTH 11
+#  define DH6OPT_AUTHPROTO_DELAYED 2
+#  define DH6OPT_AUTHPROTO_RECONFIG 3
+#  define DH6OPT_AUTHALG_HMACMD5 1
+#  define DH6OPT_AUTHRDM_MONOCOUNTER 0
+#  define DH6OPT_AUTHRECONFIG_KEY 1
+#  define DH6OPT_AUTHRECONFIG_HMACMD5 2
 #define DH6OPT_UNICAST 12
 #define DH6OPT_STATUS_CODE 13
 #  define DH6OPT_STCODE_SUCCESS 0
 #  define DH6OPT_STCODE_UNSPECFAIL 1
-#  define DH6OPT_STCODE_AUTHFAILED 2
-#  define DH6OPT_STCODE_ADDRUNAVAIL 3
-#  define DH6OPT_STCODE_NOADDRAVAIL 4
-#  define DH6OPT_STCODE_NOBINDING 5
-#  define DH6OPT_STCODE_CONFNOMATCH 6
-#  define DH6OPT_STCODE_NOTONLINK 7
-#  define DH6OPT_STCODE_USEMULTICAST 8
+#  define DH6OPT_STCODE_NOADDRAVAIL 2
+#  define DH6OPT_STCODE_NOBINDING 3
+#  define DH6OPT_STCODE_NOTONLINK 4
+#  define DH6OPT_STCODE_USEMULTICAST 5
+#  define DH6OPT_STCODE_NOPREFIXAVAIL 6
 #define DH6OPT_RAPID_COMMIT 14
 #define DH6OPT_USER_CLASS 15
 #define DH6OPT_VENDOR_CLASS 16
 #define DH6OPT_VENDOR_OPTS 17
 #define DH6OPT_INTERFACE_ID 18
 #define DH6OPT_RECONF_MSG 19
+#define DH6OPT_RECONF_ACCEPT 20
+#define DH6OPT_SIP_SERVER_D 21
+#define DH6OPT_SIP_SERVER_A 22
+#define DH6OPT_DNS 23
+#define DH6OPT_DNSNAME 24
+#define DH6OPT_IA_PD 25
+#define DH6OPT_IA_PD_PREFIX 26
 
 /*
- * The option type has not been assigned for the following options.
- * We temporarily adopt values used in the service specification document
+ * The old prefix delegation option used in the service specification document
  * (200206xx version) by NTT Communications.
- * Note that we'll change the following definitions if different type values
- * are officially assigned.
  */
-#define DH6OPT_DNS 25
 #define DH6OPT_PREFIX_DELEGATION 30
 #define DH6OPT_PREFIX_INFORMATION 31
 #define DH6OPT_PREFIX_REQUEST 32
 
+/*
+ * The following one is an unassigned number.
+ * We temporarily use values as of KAME snap 20040322.
+ */
+#define DH6OPT_NTP_SERVERS 35
+#define DH6OPT_LIFETIME 36
+
 struct dhcp6opt {
        u_int16_t dh6opt_type;
        u_int16_t dh6opt_len;
        /* type-dependent data follows */
+};
+
+struct dhcp6_ia {
+       u_int16_t dh6opt_ia_type;
+       u_int16_t dh6opt_ia_len;
+       u_int32_t dh6opt_ia_iaid;
+       u_int32_t dh6opt_ia_t1;
+       u_int32_t dh6opt_ia_t2;
+};
+
+struct dhcp6_ia_prefix {
+       u_int16_t dh6opt_ia_prefix_type;
+       u_int16_t dh6opt_ia_prefix_len;
+       u_int32_t dh6opt_ia_prefix_pltime;
+       u_int32_t dh6opt_ia_prefix_vltime;
+       u_int8_t dh6opt_ia_prefix_plen;
+       struct in6_addr dh6opt_ia_prefix_addr;
+}  __attribute__ ((__packed__));
+
+struct dhcp6_auth {
+       u_int16_t dh6opt_auth_type;
+       u_int16_t dh6opt_auth_len;
+       u_int8_t dh6opt_auth_proto;
+       u_int8_t dh6opt_auth_alg;
+       u_int8_t dh6opt_auth_rdm;
+       u_int8_t dh6opt_auth_rdinfo[8];
+       /* authentication information follows */
 } __attribute__ ((__packed__));
 
-static char *
+static const char *
 dhcp6opt_name(int type)
 {
        static char genstr[sizeof("opt_65535") + 1]; /* XXX thread unsafe */
@@ -148,27 +203,63 @@ dhcp6opt_name(int type)
                return "client ID";
        case DH6OPT_SERVERID:
                return "server ID";
+       case DH6OPT_IA_NA:
+               return "IA_NA";
        case DH6OPT_ORO:
                return "option request";
        case DH6OPT_PREFERENCE:
                return "preference";
+       case DH6OPT_ELAPSED_TIME:
+               return "elapsed time";
+       case DH6OPT_RELAY_MSG:
+               return "relay message";
+       case DH6OPT_AUTH:
+               return "authentication";
+       case DH6OPT_UNICAST:
+               return "server unicast";
        case DH6OPT_STATUS_CODE:
                return "status code";
        case DH6OPT_RAPID_COMMIT:
                return "rapid commit";
+       case DH6OPT_USER_CLASS:
+               return "user class";
+       case DH6OPT_VENDOR_CLASS:
+               return "vendor class";
+       case DH6OPT_VENDOR_OPTS:
+               return "vendor-specific info";
+       case DH6OPT_INTERFACE_ID:
+               return "interface ID";
+       case DH6OPT_RECONF_MSG:
+               return "reconfigure message";
+       case DH6OPT_RECONF_ACCEPT:
+               return "reconfigure accept";
+       case DH6OPT_SIP_SERVER_D:
+               return "SIP servers domain";
+       case DH6OPT_SIP_SERVER_A:
+               return "SIP servers address";
        case DH6OPT_DNS:
                return "DNS";
+       case DH6OPT_DNSNAME:
+               return "DNS name";
        case DH6OPT_PREFIX_DELEGATION:
                return "prefix delegation";
        case DH6OPT_PREFIX_INFORMATION:
                return "prefix information";
+       case DH6OPT_IA_PD:
+               return "IA_PD";
+       case DH6OPT_IA_PD_PREFIX:
+               return "IA_PD prefix";
+       case DH6OPT_NTP_SERVERS:
+               return "NTP Server";
+       case DH6OPT_LIFETIME:
+               return "lifetime";
        default:
-               sprintf(genstr, "opt_%d", type);
+               snprintf(genstr, sizeof(genstr), "opt_%d", type);
                return(genstr);
        }
 }
 
-static char *
+static const char *
 dhcp6stcode(int code)
 {
        static char genstr[sizeof("code255") + 1]; /* XXX thread unsafe */
@@ -181,47 +272,48 @@ dhcp6stcode(int code)
                return "success";
        case DH6OPT_STCODE_UNSPECFAIL:
                return "unspec failure";
-       case DH6OPT_STCODE_AUTHFAILED:
-               return "auth fail";
-       case DH6OPT_STCODE_ADDRUNAVAIL:
-               return "address unavailable";
        case DH6OPT_STCODE_NOADDRAVAIL:
                return "no addresses";
        case DH6OPT_STCODE_NOBINDING:
                return "no binding";
-       case DH6OPT_STCODE_CONFNOMATCH:
-               return "confirm no match";
        case DH6OPT_STCODE_NOTONLINK:
                return "not on-link";
        case DH6OPT_STCODE_USEMULTICAST:
                return "use multicast";
+       case DH6OPT_STCODE_NOPREFIXAVAIL:
+               return "no prefixes";
        default:
-               sprintf(genstr, "code%d", code);
+               snprintf(genstr, sizeof(genstr), "code%d", code);
                return(genstr);
        }
 }
 
 static void
-dhcp6opt_print(u_char *cp, u_char *ep)
+dhcp6opt_print(const u_char *cp, const u_char *ep)
 {
        struct dhcp6opt *dh6o;
        u_char *tp;
-       int i, opttype;
+       size_t i;
+       u_int16_t opttype;
        size_t optlen;
        u_int16_t val16;
        u_int32_t val32;
        struct in6_addr addr6;
+       struct dhcp6_ia ia;
+       struct dhcp6_ia_prefix ia_prefix;
+       struct dhcp6_auth authopt;
+       u_int authinfolen, authrealmlen;
 
        if (cp == ep)
                return;
        while (cp < ep) {
-               if (ep - cp < sizeof(*dh6o))
+               if (ep < cp + sizeof(*dh6o))
                        goto trunc;
                dh6o = (struct dhcp6opt *)cp;
-               optlen = ntohs(dh6o->dh6opt_len);
-               if (ep - cp < sizeof(*dh6o) + optlen)
+               optlen = EXTRACT_16BITS(&dh6o->dh6opt_len);
+               if (ep < cp + sizeof(*dh6o) + optlen)
                        goto trunc;
-               opttype = ntohs(dh6o->dh6opt_type);
+               opttype = EXTRACT_16BITS(&dh6o->dh6opt_type);
                printf(" (%s", dhcp6opt_name(opttype));
                switch (opttype) {
                case DH6OPT_CLIENTID:
@@ -232,12 +324,12 @@ dhcp6opt_print(u_char *cp, u_char *ep)
                                break;
                        }
                        tp = (u_char *)(dh6o + 1);
-                       switch (ntohs(*(u_int16_t *)tp)) {
+                       switch (EXTRACT_16BITS(tp)) {
                        case 1:
                                if (optlen >= 2 + 6) {
                                        printf(" hwaddr/time type %u time %u ",
-                                           ntohs(*(u_int16_t *)&tp[2]),
-                                           ntohl(*(u_int32_t *)&tp[4]));
+                                           EXTRACT_16BITS(&tp[2]),
+                                           EXTRACT_32BITS(&tp[4]));
                                        for (i = 8; i < optlen; i++)
                                                printf("%02x", tp[i]);
                                        /*(*/
@@ -262,7 +354,7 @@ dhcp6opt_print(u_char *cp, u_char *ep)
                        case 3:
                                if (optlen >= 2 + 2) {
                                        printf(" hwaddr type %u ",
-                                           ntohs(*(u_int16_t *)&tp[2]));
+                                           EXTRACT_16BITS(&tp[2]));
                                        for (i = 4; i < optlen; i++)
                                                printf("%02x", tp[i]);
                                        /*(*/
@@ -273,7 +365,7 @@ dhcp6opt_print(u_char *cp, u_char *ep)
                                }
                                break;
                        default:
-                               printf(" type %d)", ntohs(*(u_int16_t *)tp));
+                               printf(" type %d)", EXTRACT_16BITS(tp));
                                break;
                        }
                        break;
@@ -298,10 +390,142 @@ dhcp6opt_print(u_char *cp, u_char *ep)
                        }
                        printf(" %d)", *((u_char *)(dh6o + 1) + 1));
                        break;
+               case DH6OPT_ELAPSED_TIME:
+                       if (optlen != 2) {
+                               printf(" ?)");
+                               break;
+                       }
+                       memcpy(&val16, dh6o + 1, sizeof(val16));
+                       val16 = ntohs(val16);
+                       printf(" %d)", (int)val16);
+                       break;
+               case DH6OPT_RELAY_MSG:
+                       printf(" (");
+                       dhcp6_print((const u_char *)(dh6o + 1), optlen);
+                       printf(")");
+                       break;
+               case DH6OPT_AUTH:
+                       if (optlen < sizeof(authopt) - sizeof(*dh6o)) {
+                               printf(" ?)");
+                               break;
+                       }
+                       memcpy(&authopt, dh6o, sizeof(authopt));
+                       switch (authopt.dh6opt_auth_proto) {
+                       case DH6OPT_AUTHPROTO_DELAYED:
+                               printf(" proto: delayed");
+                               break;
+                       case DH6OPT_AUTHPROTO_RECONFIG:
+                               printf(" proto: reconfigure");
+                               break;
+                       default:
+                               printf(" proto: %d",
+                                   authopt.dh6opt_auth_proto);
+                               break;
+                       }
+                       switch (authopt.dh6opt_auth_alg) {
+                       case DH6OPT_AUTHALG_HMACMD5:
+                               /* XXX: may depend on the protocol */
+                               printf(", alg: HMAC-MD5");
+                               break;
+                       default:
+                               printf(", alg: %d", authopt.dh6opt_auth_alg);
+                               break;
+                       }
+                       switch (authopt.dh6opt_auth_rdm) {
+                       case DH6OPT_AUTHRDM_MONOCOUNTER:
+                               printf(", RDM: mono");
+                               break;
+                       default:
+                               printf(", RDM: %d", authopt.dh6opt_auth_rdm);
+                               break;
+                       }
+                       tp = (u_char *)&authopt.dh6opt_auth_rdinfo;
+                       printf(", RD:");
+                       for (i = 0; i < 4; i++, tp += sizeof(val16))
+                               printf(" %04x", EXTRACT_16BITS(tp));
+
+                       /* protocol dependent part */
+                       tp = (u_char *)dh6o + sizeof(authopt);
+                       authinfolen =
+                           optlen + sizeof(*dh6o) - sizeof(authopt); 
+                       switch (authopt.dh6opt_auth_proto) {
+                       case DH6OPT_AUTHPROTO_DELAYED:
+                               if (authinfolen == 0)
+                                       break;
+                               if (authinfolen < 20) {
+                                       printf(" ??");
+                                       break;
+                               }
+                               authrealmlen = authinfolen - 20;
+                               if (authrealmlen > 0) {
+                                       printf(", realm: ");
+                               }
+                               for (i = 0; i < authrealmlen; i++, tp++)
+                                       printf("%02x", *tp);
+                               printf(", key ID: %08x", EXTRACT_32BITS(tp));
+                               tp += 4;
+                               printf(", HMAC-MD5:");
+                               for (i = 0; i < 4; i++, tp+= 4)
+                                       printf(" %08x", EXTRACT_32BITS(tp));
+                               break;
+                       case DH6OPT_AUTHPROTO_RECONFIG:
+                               if (authinfolen != 17) {
+                                       printf(" ??");
+                                       break;
+                               }
+                               switch (*tp++) {
+                               case DH6OPT_AUTHRECONFIG_KEY:
+                                       printf(" reconfig-key");
+                                       break;
+                               case DH6OPT_AUTHRECONFIG_HMACMD5:
+                                       printf(" type: HMAC-MD5");
+                                       break;
+                               default:
+                                       printf(" type: ??");
+                                       break;
+                               }
+                               printf(" value:");
+                               for (i = 0; i < 4; i++, tp+= 4)
+                                       printf(" %08x", EXTRACT_32BITS(tp));
+                               break;
+                       default:
+                               printf(" ??");
+                               break;
+                       }
+
+                       printf(")");
+                       break;
                case DH6OPT_RAPID_COMMIT: /* nothing todo */
                        printf(")");
                        break;
+               case DH6OPT_INTERFACE_ID:
+                       /*
+                        * Since we cannot predict the encoding, print hex dump
+                        * at most 10 characters.
+                        */
+                       for (i = 0; i < optlen && i < 10; i++)
+                               printf("%02x", ((u_char *)(dh6o + 1))[i]);
+                       break;
+               case DH6OPT_RECONF_MSG:
+                       tp = (u_char *)(dh6o + 1);
+                       switch (*tp) {
+                       case DH6_RENEW:
+                               printf(" for renew)");
+                               break;
+                       case DH6_INFORM_REQ:
+                               printf(" for inf-req)");
+                               break;
+                       default:
+                               printf(" for ?\?\?(%02x))", *tp);
+                               break;
+                       }
+                       break;
+               case DH6OPT_RECONF_ACCEPT: /* nothing todo */
+                       printf(")");
+                       break;
+               case DH6OPT_SIP_SERVER_A:
                case DH6OPT_DNS:
+               case DH6OPT_NTP_SERVERS:
                        if (optlen % 16) {
                                printf(" ?)");
                                break;
@@ -331,14 +555,70 @@ dhcp6opt_print(u_char *cp, u_char *ep)
                                printf(" lease-duration: %u)", val32);
                        break;
                case DH6OPT_STATUS_CODE:
-                       if (optlen < 2)
+                       if (optlen < 2) {
                                printf(" ?)");
+                               break;
+                       }
                        memcpy(&val16, (u_char *)(dh6o + 1), sizeof(val16));
                        val16 = ntohs(val16);
                        printf(" %s)", dhcp6stcode(val16));
                        break;
+               case DH6OPT_IA_NA:
+               case DH6OPT_IA_PD:
+                       if (optlen < sizeof(ia) - 4) {
+                               printf(" ?)");
+                               break;
+                       }
+                       memcpy(&ia, (u_char *)dh6o, sizeof(ia));
+                       ia.dh6opt_ia_iaid = ntohl(ia.dh6opt_ia_iaid);
+                       ia.dh6opt_ia_t1 = ntohl(ia.dh6opt_ia_t1);
+                       ia.dh6opt_ia_t2 = ntohl(ia.dh6opt_ia_t2);
+                       printf(" IAID:%lu T1:%lu T2:%lu",
+                           (unsigned long)ia.dh6opt_ia_iaid,
+                           (unsigned long)ia.dh6opt_ia_t1,
+                           (unsigned long)ia.dh6opt_ia_t2);
+                       if (optlen > sizeof(ia) - 4) {
+                               /* there are sub-options */
+                               dhcp6opt_print((u_char *)dh6o + sizeof(ia),
+                                   (u_char *)(dh6o + 1) + optlen);
+                       }
+                       printf(")");
+                       break;
+               case DH6OPT_IA_PD_PREFIX:
+                       if (optlen < sizeof(ia_prefix) - 4) {
+                               printf(" ?)");
+                               break;
+                       }
+                       memcpy(&ia_prefix, (u_char *)dh6o, sizeof(ia_prefix));
+                       printf(" %s/%d",
+                           ip6addr_string(&ia_prefix.dh6opt_ia_prefix_addr),
+                           ia_prefix.dh6opt_ia_prefix_plen);
+                       ia_prefix.dh6opt_ia_prefix_pltime =
+                           ntohl(ia_prefix.dh6opt_ia_prefix_pltime);
+                       ia_prefix.dh6opt_ia_prefix_vltime =
+                           ntohl(ia_prefix.dh6opt_ia_prefix_vltime);
+                       printf(" pltime:%lu vltime:%lu",
+                           (unsigned long)ia_prefix.dh6opt_ia_prefix_pltime,
+                           (unsigned long)ia_prefix.dh6opt_ia_prefix_vltime);
+                       if (optlen > sizeof(ia_prefix) - 4) {
+                               /* there are sub-options */
+                               dhcp6opt_print((u_char *)dh6o +
+                                   sizeof(ia_prefix),
+                                   (u_char *)(dh6o + 1) + optlen);
+                       }
+                       printf(")");
+                       break;
+               case DH6OPT_LIFETIME:
+                       if (optlen != 4) {
+                               printf(" ?)");
+                               break;
+                       }
+                       memcpy(&val32, dh6o + 1, sizeof(val32));
+                       val32 = ntohl(val32);
+                       printf(" %d)", (int)val32);
+                       break;
                default:
-                       printf(")", ntohs(dh6o->dh6opt_type));
+                       printf(")");
                        break;
                }
 
@@ -354,19 +634,22 @@ trunc:
  * Print dhcp6 packets
  */
 void
-dhcp6_print(register const u_char *cp, u_int length,
-           u_int16_t sport, u_int16_t dport)
+dhcp6_print(const u_char *cp, u_int length)
 {
        struct dhcp6 *dh6;
-       u_char *ep;
+       struct dhcp6_relay *dh6relay;
+       const u_char *ep;
        u_char *extp;
        const char *name;
 
        printf("dhcp6");
 
        ep = (u_char *)snapend;
+       if (cp + length < ep)
+               ep = cp + length;
 
        dh6 = (struct dhcp6 *)cp;
+       dh6relay = (struct dhcp6_relay *)cp;
        TCHECK(dh6->dh6_xid);
        switch (dh6->dh6_msgtype) {
        case DH6_SOLICIT:
@@ -390,9 +673,24 @@ dhcp6_print(register const u_char *cp, u_int length,
        case DH6_REPLY:
                name = "reply";
                break;
+       case DH6_RELEASE:
+               name = "release";
+               break;
+       case DH6_DECLINE:
+               name = "decline";
+               break;
+       case DH6_RECONFIGURE:
+               name = "reconfigure";
+               break;
        case DH6_INFORM_REQ:
                name= "inf-req";
                break;
+       case DH6_RELAY_FORW:
+               name= "relay-fwd";
+               break;
+       case DH6_RELAY_REPLY:
+               name= "relay-reply";
+               break;
        default:
                name = NULL;
                break;
@@ -401,8 +699,10 @@ dhcp6_print(register const u_char *cp, u_int length,
        if (!vflag) {
                if (name)
                        printf(" %s", name);
-               else
+               else if (dh6->dh6_msgtype != DH6_RELAY_FORW &&
+                   dh6->dh6_msgtype != DH6_RELAY_REPLY) {
                        printf(" msgtype-%u", dh6->dh6_msgtype);
+               }
                return;
        }
 
@@ -412,9 +712,24 @@ dhcp6_print(register const u_char *cp, u_int length,
                printf(" %s (", name);  /*)*/
        else
                printf(" msgtype-%u (", dh6->dh6_msgtype);      /*)*/
-       printf("xid=%x", ntohl(dh6->dh6_xid) & DH6_XIDMASK);
-       extp = (u_char *)(dh6 + 1);
-       dhcp6opt_print(extp, ep);
+       if (dh6->dh6_msgtype != DH6_RELAY_FORW &&
+           dh6->dh6_msgtype != DH6_RELAY_REPLY) {
+               printf("xid=%x", EXTRACT_32BITS(&dh6->dh6_xid) & DH6_XIDMASK);
+               extp = (u_char *)(dh6 + 1);
+               dhcp6opt_print(extp, ep);
+       } else {                /* relay messages */
+               struct in6_addr addr6;
+
+               TCHECK(dh6relay->dh6relay_peeraddr);
+
+               memcpy(&addr6, dh6relay->dh6relay_linkaddr, sizeof (addr6));
+               printf("linkaddr=%s", ip6addr_string(&addr6));
+
+               memcpy(&addr6, dh6relay->dh6relay_peeraddr, sizeof (addr6));
+               printf(" peeraddr=%s", ip6addr_string(&addr6));
+
+               dhcp6opt_print((u_char *)(dh6relay + 1), ep);
+       }
        /*(*/
        printf(")");
        return;