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    1 /*
    2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
    3  *  The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that: (1) source code distributions
    7  * retain the above copyright notice and this paragraph in its entirety, (2)
    8  * distributions including binary code include the above copyright notice and
    9  * this paragraph in its entirety in the documentation or other materials
   10  * provided with the distribution, and (3) all advertising materials mentioning
   11  * features or use of this software display the following acknowledgement:
   12  * ``This product includes software developed by the University of California,
   13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
   14  * the University nor the names of its contributors may be used to endorse
   15  * or promote products derived from this software without specific prior
   16  * written permission.
   17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
   18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
   19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   20  */
   21 
   22 /* \summary: Address Resolution Protocol (ARP) printer */
   23 
   24 #ifdef HAVE_CONFIG_H
   25 #include <config.h>
   26 #endif
   27 
   28 #include "netdissect-stdinc.h"
   29 
   30 #define ND_LONGJMP_FROM_TCHECK
   31 #include "netdissect.h"
   32 #include "addrtoname.h"
   33 #include "ethertype.h"
   34 #include "extract.h"
   35 
   36 
   37 /*
   38  * Address Resolution Protocol.
   39  *
   40  * See RFC 826 for protocol description.  ARP packets are variable
   41  * in size; the arphdr structure defines the fixed-length portion.
   42  * Protocol type values are the same as those for 10 Mb/s Ethernet.
   43  * It is followed by the variable-sized fields ar_sha, arp_spa,
   44  * arp_tha and arp_tpa in that order, according to the lengths
   45  * specified.  Field names used correspond to RFC 826.
   46  */
   47 struct  arp_pkthdr {
   48         nd_uint16_t ar_hrd;     /* format of hardware address */
   49 #define ARPHRD_ETHER    1       /* ethernet hardware format */
   50 #define ARPHRD_IEEE802  6       /* token-ring hardware format */
   51 #define ARPHRD_ARCNET   7       /* arcnet hardware format */
   52 #define ARPHRD_FRELAY   15      /* frame relay hardware format */
   53 #define ARPHRD_ATM2225  19      /* ATM (RFC 2225) */
   54 #define ARPHRD_STRIP    23      /* Ricochet Starmode Radio hardware format */
   55 #define ARPHRD_IEEE1394 24      /* IEEE 1394 (FireWire) hardware format */
   56 #define ARPHRD_INFINIBAND 32    /* InfiniBand RFC 4391 */
   57         nd_uint16_t ar_pro;     /* format of protocol address */
   58         nd_uint8_t  ar_hln;     /* length of hardware address */
   59         nd_uint8_t  ar_pln;     /* length of protocol address */
   60         nd_uint16_t ar_op;      /* one of: */
   61 #define ARPOP_REQUEST   1       /* request to resolve address */
   62 #define ARPOP_REPLY     2       /* response to previous request */
   63 #define ARPOP_REVREQUEST 3      /* request protocol address given hardware */
   64 #define ARPOP_REVREPLY  4       /* response giving protocol address */
   65 #define ARPOP_INVREQUEST 8      /* request to identify peer */
   66 #define ARPOP_INVREPLY  9       /* response identifying peer */
   67 #define ARPOP_NAK       10      /* NAK - only valif for ATM ARP */
   68 
   69 /*
   70  * The remaining fields are variable in size,
   71  * according to the sizes above.
   72  */
   73 #ifdef COMMENT_ONLY
   74     nd_byte     ar_sha[];   /* sender hardware address */
   75     nd_byte     ar_spa[];   /* sender protocol address */
   76     nd_byte     ar_tha[];   /* target hardware address */
   77     nd_byte     ar_tpa[];   /* target protocol address */
   78 #endif
   79 #define ar_sha(ap)  (((const u_char *)((ap)+1))+  0)
   80 #define ar_spa(ap)  (((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln))
   81 #define ar_tha(ap)  (((const u_char *)((ap)+1))+  GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
   82 #define ar_tpa(ap)  (((const u_char *)((ap)+1))+2*GET_U_1((ap)->ar_hln)+GET_U_1((ap)->ar_pln))
   83 };
   84 
   85 #define ARP_HDRLEN  8
   86 
   87 #define HRD(ap) GET_BE_U_2((ap)->ar_hrd)
   88 #define HRD_LEN(ap) GET_U_1((ap)->ar_hln)
   89 #define PROTO_LEN(ap) GET_U_1((ap)->ar_pln)
   90 #define OP(ap)  GET_BE_U_2((ap)->ar_op)
   91 #define PRO(ap) GET_BE_U_2((ap)->ar_pro)
   92 #define SHA(ap) (ar_sha(ap))
   93 #define SPA(ap) (ar_spa(ap))
   94 #define THA(ap) (ar_tha(ap))
   95 #define TPA(ap) (ar_tpa(ap))
   96 
   97 
   98 static const struct tok arpop_values[] = {
   99     { ARPOP_REQUEST, "Request" },
  100     { ARPOP_REPLY, "Reply" },
  101     { ARPOP_REVREQUEST, "Reverse Request" },
  102     { ARPOP_REVREPLY, "Reverse Reply" },
  103     { ARPOP_INVREQUEST, "Inverse Request" },
  104     { ARPOP_INVREPLY, "Inverse Reply" },
  105     { ARPOP_NAK, "NACK Reply" },
  106     { 0, NULL }
  107 };
  108 
  109 static const struct tok arphrd_values[] = {
  110     { ARPHRD_ETHER, "Ethernet" },
  111     { ARPHRD_IEEE802, "TokenRing" },
  112     { ARPHRD_ARCNET, "ArcNet" },
  113     { ARPHRD_FRELAY, "FrameRelay" },
  114     { ARPHRD_STRIP, "Strip" },
  115     { ARPHRD_IEEE1394, "IEEE 1394" },
  116     { ARPHRD_ATM2225, "ATM" },
  117     { ARPHRD_INFINIBAND, "InfiniBand" },
  118     { 0, NULL }
  119 };
  120 
  121 /*
  122  * ATM Address Resolution Protocol.
  123  *
  124  * See RFC 2225 for protocol description.  ATMARP packets are similar
  125  * to ARP packets, except that there are no length fields for the
  126  * protocol address - instead, there are type/length fields for
  127  * the ATM number and subaddress - and the hardware addresses consist
  128  * of an ATM number and an ATM subaddress.
  129  */
  130 struct  atmarp_pkthdr {
  131         nd_uint16_t aar_hrd;    /* format of hardware address */
  132         nd_uint16_t aar_pro;    /* format of protocol address */
  133         nd_uint8_t  aar_shtl;   /* length of source ATM number */
  134         nd_uint8_t  aar_sstl;   /* length of source ATM subaddress */
  135 #define ATMARP_IS_E164  0x40    /* bit in type/length for E.164 format */
  136 #define ATMARP_LEN_MASK 0x3F    /* length of {sub}address in type/length */
  137         nd_uint16_t aar_op;     /* same as regular ARP */
  138         nd_uint8_t  aar_spln;   /* length of source protocol address */
  139         nd_uint8_t  aar_thtl;   /* length of target ATM number */
  140         nd_uint8_t  aar_tstl;   /* length of target ATM subaddress */
  141         nd_uint8_t  aar_tpln;   /* length of target protocol address */
  142 /*
  143  * The remaining fields are variable in size,
  144  * according to the sizes above.
  145  */
  146 #ifdef COMMENT_ONLY
  147     nd_byte     aar_sha[];  /* source ATM number */
  148     nd_byte     aar_ssa[];  /* source ATM subaddress */
  149     nd_byte     aar_spa[];  /* sender protocol address */
  150     nd_byte     aar_tha[];  /* target ATM number */
  151     nd_byte     aar_tsa[];  /* target ATM subaddress */
  152     nd_byte     aar_tpa[];  /* target protocol address */
  153 #endif
  154 
  155 #define ATMHRD(ap)  GET_BE_U_2((ap)->aar_hrd)
  156 #define ATMSHRD_LEN(ap) (GET_U_1((ap)->aar_shtl) & ATMARP_LEN_MASK)
  157 #define ATMSSLN(ap) (GET_U_1((ap)->aar_sstl) & ATMARP_LEN_MASK)
  158 #define ATMSPROTO_LEN(ap) GET_U_1((ap)->aar_spln)
  159 #define ATMOP(ap)   GET_BE_U_2((ap)->aar_op)
  160 #define ATMPRO(ap)  GET_BE_U_2((ap)->aar_pro)
  161 #define ATMTHRD_LEN(ap) (GET_U_1((ap)->aar_thtl) & ATMARP_LEN_MASK)
  162 #define ATMTSLN(ap) (GET_U_1((ap)->aar_tstl) & ATMARP_LEN_MASK)
  163 #define ATMTPROTO_LEN(ap) GET_U_1((ap)->aar_tpln)
  164 #define aar_sha(ap) ((const u_char *)((ap)+1))
  165 #define aar_ssa(ap) (aar_sha(ap) + ATMSHRD_LEN(ap))
  166 #define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap))
  167 #define aar_tha(ap) (aar_spa(ap) + ATMSPROTO_LEN(ap))
  168 #define aar_tsa(ap) (aar_tha(ap) + ATMTHRD_LEN(ap))
  169 #define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap))
  170 };
  171 
  172 #define ATMSHA(ap) (aar_sha(ap))
  173 #define ATMSSA(ap) (aar_ssa(ap))
  174 #define ATMSPA(ap) (aar_spa(ap))
  175 #define ATMTHA(ap) (aar_tha(ap))
  176 #define ATMTSA(ap) (aar_tsa(ap))
  177 #define ATMTPA(ap) (aar_tpa(ap))
  178 
  179 static int
  180 isnonzero(netdissect_options *ndo, const u_char *a, size_t len)
  181 {
  182     while (len > 0) {
  183         if (GET_U_1(a) != 0)
  184             return (1);
  185         a++;
  186         len--;
  187     }
  188     return (0);
  189 }
  190 
  191 static void
  192 tpaddr_print_ip(netdissect_options *ndo,
  193             const struct arp_pkthdr *ap, u_short pro)
  194 {
  195     if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
  196         ND_PRINT("<wrong proto type>");
  197     else if (PROTO_LEN(ap) != 4)
  198         ND_PRINT("<wrong len>");
  199     else
  200         ND_PRINT("%s", GET_IPADDR_STRING(TPA(ap)));
  201 }
  202 
  203 static void
  204 spaddr_print_ip(netdissect_options *ndo,
  205             const struct arp_pkthdr *ap, u_short pro)
  206 {
  207     if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
  208         ND_PRINT("<wrong proto type>");
  209     else if (PROTO_LEN(ap) != 4)
  210         ND_PRINT("<wrong len>");
  211     else
  212         ND_PRINT("%s", GET_IPADDR_STRING(SPA(ap)));
  213 }
  214 
  215 static void
  216 atmarp_addr_print(netdissect_options *ndo,
  217           const u_char *ha, u_int ha_len, const u_char *srca,
  218     u_int srca_len)
  219 {
  220     if (ha_len == 0)
  221         ND_PRINT("<No address>");
  222     else {
  223         ND_PRINT("%s", GET_LINKADDR_STRING(ha, LINKADDR_ATM, ha_len));
  224         if (srca_len != 0)
  225             ND_PRINT(",%s",
  226                   GET_LINKADDR_STRING(srca, LINKADDR_ATM, srca_len));
  227     }
  228 }
  229 
  230 static void
  231 atmarp_tpaddr_print(netdissect_options *ndo,
  232             const struct atmarp_pkthdr *ap, u_short pro)
  233 {
  234     if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
  235         ND_PRINT("<wrong proto type>");
  236     else if (ATMTPROTO_LEN(ap) != 4)
  237         ND_PRINT("<wrong tplen>");
  238     else
  239         ND_PRINT("%s", GET_IPADDR_STRING(ATMTPA(ap)));
  240 }
  241 
  242 static void
  243 atmarp_spaddr_print(netdissect_options *ndo,
  244             const struct atmarp_pkthdr *ap, u_short pro)
  245 {
  246     if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
  247         ND_PRINT("<wrong proto type>");
  248     else if (ATMSPROTO_LEN(ap) != 4)
  249         ND_PRINT("<wrong splen>");
  250     else
  251         ND_PRINT("%s", GET_IPADDR_STRING(ATMSPA(ap)));
  252 }
  253 
  254 static void
  255 atmarp_print(netdissect_options *ndo,
  256          const u_char *bp, u_int length, u_int caplen)
  257 {
  258     const struct atmarp_pkthdr *ap;
  259     u_short pro, hrd, op;
  260 
  261     ap = (const struct atmarp_pkthdr *)bp;
  262     ND_TCHECK_SIZE(ap);
  263 
  264     hrd = ATMHRD(ap);
  265     pro = ATMPRO(ap);
  266     op = ATMOP(ap);
  267 
  268     ND_TCHECK_LEN(ATMTPA(ap), ATMTPROTO_LEN(ap));
  269 
  270         if (!ndo->ndo_eflag) {
  271             ND_PRINT("ARP, ");
  272         }
  273 
  274     if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
  275         ATMSPROTO_LEN(ap) != 4 ||
  276             ATMTPROTO_LEN(ap) != 4 ||
  277             ndo->ndo_vflag) {
  278                 ND_PRINT("%s, %s (len %u/%u)",
  279                           tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
  280                           tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
  281                           ATMSPROTO_LEN(ap),
  282                           ATMTPROTO_LEN(ap));
  283 
  284                 /* don't know about the address formats */
  285                 if (!ndo->ndo_vflag) {
  286                     goto out;
  287                 }
  288     }
  289 
  290         /* print operation */
  291         ND_PRINT("%s%s ",
  292                ndo->ndo_vflag ? ", " : "",
  293                tok2str(arpop_values, "Unknown (%u)", op));
  294 
  295     switch (op) {
  296 
  297     case ARPOP_REQUEST:
  298         ND_PRINT("who-has ");
  299         atmarp_tpaddr_print(ndo, ap, pro);
  300         if (ATMTHRD_LEN(ap) != 0) {
  301             ND_PRINT(" (");
  302             atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
  303                 ATMTSA(ap), ATMTSLN(ap));
  304             ND_PRINT(")");
  305         }
  306         ND_PRINT(" tell ");
  307         atmarp_spaddr_print(ndo, ap, pro);
  308         break;
  309 
  310     case ARPOP_REPLY:
  311         atmarp_spaddr_print(ndo, ap, pro);
  312         ND_PRINT(" is-at ");
  313         atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
  314                                   ATMSSLN(ap));
  315         break;
  316 
  317     case ARPOP_INVREQUEST:
  318         ND_PRINT("who-is ");
  319         atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
  320             ATMTSLN(ap));
  321         ND_PRINT(" tell ");
  322         atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
  323             ATMSSLN(ap));
  324         break;
  325 
  326     case ARPOP_INVREPLY:
  327         atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
  328             ATMSSLN(ap));
  329         ND_PRINT("at ");
  330         atmarp_spaddr_print(ndo, ap, pro);
  331         break;
  332 
  333     case ARPOP_NAK:
  334         ND_PRINT("for ");
  335         atmarp_spaddr_print(ndo, ap, pro);
  336         break;
  337 
  338     default:
  339         ND_DEFAULTPRINT((const u_char *)ap, caplen);
  340         return;
  341     }
  342 
  343  out:
  344         ND_PRINT(", length %u", length);
  345 }
  346 
  347 void
  348 arp_print(netdissect_options *ndo,
  349       const u_char *bp, u_int length, u_int caplen)
  350 {
  351     const struct arp_pkthdr *ap;
  352     u_short pro, hrd, op, linkaddr;
  353 
  354     ndo->ndo_protocol = "arp";
  355     ap = (const struct arp_pkthdr *)bp;
  356     ND_TCHECK_SIZE(ap);
  357 
  358     hrd = HRD(ap);
  359     pro = PRO(ap);
  360     op = OP(ap);
  361 
  362 
  363         /* if its ATM then call the ATM ARP printer
  364            for Frame-relay ARP most of the fields
  365            are similar to Ethernet so overload the Ethernet Printer
  366            and set the linkaddr type for GET_LINKADDR_STRING() accordingly */
  367 
  368         switch(hrd) {
  369         case ARPHRD_ATM2225:
  370             atmarp_print(ndo, bp, length, caplen);
  371             return;
  372         case ARPHRD_FRELAY:
  373             linkaddr = LINKADDR_FRELAY;
  374             break;
  375         default:
  376             linkaddr = LINKADDR_ETHER;
  377             break;
  378     }
  379 
  380     ND_TCHECK_LEN(TPA(ap), PROTO_LEN(ap));
  381 
  382         if (!ndo->ndo_eflag) {
  383             ND_PRINT("ARP, ");
  384         }
  385 
  386         /* print hardware type/len and proto type/len */
  387         if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
  388         PROTO_LEN(ap) != 4 ||
  389             HRD_LEN(ap) == 0 ||
  390             ndo->ndo_vflag) {
  391             ND_PRINT("%s (len %u), %s (len %u)",
  392                       tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
  393                       HRD_LEN(ap),
  394                       tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
  395                       PROTO_LEN(ap));
  396 
  397             /* don't know about the address formats */
  398             if (!ndo->ndo_vflag) {
  399                 goto out;
  400             }
  401     }
  402 
  403         /* print operation */
  404         ND_PRINT("%s%s ",
  405                ndo->ndo_vflag ? ", " : "",
  406                tok2str(arpop_values, "Unknown (%u)", op));
  407 
  408     switch (op) {
  409 
  410     case ARPOP_REQUEST:
  411         ND_PRINT("who-has ");
  412         tpaddr_print_ip(ndo, ap, pro);
  413         if (isnonzero(ndo, (const u_char *)THA(ap), HRD_LEN(ap)))
  414             ND_PRINT(" (%s)",
  415                   GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
  416         ND_PRINT(" tell ");
  417         spaddr_print_ip(ndo, ap, pro);
  418         break;
  419 
  420     case ARPOP_REPLY:
  421         spaddr_print_ip(ndo, ap, pro);
  422         ND_PRINT(" is-at %s",
  423                           GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
  424         break;
  425 
  426     case ARPOP_REVREQUEST:
  427         /*
  428          * XXX - GET_LINKADDR_STRING() may return a pointer to
  429          * a static buffer, so we only have one call to it per
  430          * ND_PRINT() call.
  431          *
  432          * This should be done in a cleaner fashion.
  433          */
  434         ND_PRINT("who-is %s",
  435               GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
  436         ND_PRINT(" tell %s",
  437               GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
  438         break;
  439 
  440     case ARPOP_REVREPLY:
  441         ND_PRINT("%s at ",
  442               GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
  443         tpaddr_print_ip(ndo, ap, pro);
  444         break;
  445 
  446     case ARPOP_INVREQUEST:
  447         /*
  448          * XXX - GET_LINKADDR_STRING() may return a pointer to
  449          * a static buffer, so we only have one call to it per
  450          * ND_PRINT() call.
  451          *
  452          * This should be done in a cleaner fashion.
  453          */
  454         ND_PRINT("who-is %s",
  455               GET_LINKADDR_STRING(THA(ap), linkaddr, HRD_LEN(ap)));
  456         ND_PRINT(" tell %s",
  457               GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
  458         break;
  459 
  460     case ARPOP_INVREPLY:
  461         ND_PRINT("%s at ",
  462               GET_LINKADDR_STRING(SHA(ap), linkaddr, HRD_LEN(ap)));
  463         spaddr_print_ip(ndo, ap, pro);
  464         break;
  465 
  466     default:
  467         ND_DEFAULTPRINT((const u_char *)ap, caplen);
  468         return;
  469     }
  470 
  471  out:
  472         ND_PRINT(", length %u", length);
  473 }