contrib/tcpdump/print-rpki-rtr.c

   1 /*
   2  * Copyright (c) 1998-2011 The TCPDUMP project
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that: (1) source code
   6  * distributions retain the above copyright notice and this paragraph
   7  * in its entirety, and (2) distributions including binary code include
   8  * the above copyright notice and this paragraph in its entirety in
   9  * the documentation or other materials provided with the distribution.
  10  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  11  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  12  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  13  * FOR A PARTICULAR PURPOSE.
  14  *
  15  * Original code by Hannes Gredler (hannes@gredler.at)
  16  */
  17
  18 /* \summary: Resource Public Key Infrastructure (RPKI) to Router Protocol printer */
  19
  20 /* specification: RFC 6810 */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include "netdissect-stdinc.h"
  27
  28 #define ND_LONGJMP_FROM_TCHECK
  29 #include "netdissect.h"
  30 #include "extract.h"
  31 #include "addrtoname.h"
  32
  33
  34 /*
  35  * RPKI/Router PDU header
  36  *
  37  * Here's what the PDU header looks like.
  38  * The length does include the version and length fields.
  39  */
  40 typedef struct rpki_rtr_pdu_ {
  41     nd_uint8_t version;         /* Version number */
  42     nd_uint8_t pdu_type;                /* PDU type */
  43     union {
  44         nd_uint16_t session_id; /* Session id */
  45         nd_uint16_t error_code; /* Error code */
  46     } u;
  47     nd_uint32_t length;
  48 } rpki_rtr_pdu;
  49
  50 /*
  51  * IPv4 Prefix PDU.
  52  */
  53 typedef struct rpki_rtr_pdu_ipv4_prefix_ {
  54     rpki_rtr_pdu pdu_header;
  55     nd_uint8_t flags;
  56     nd_uint8_t prefix_length;
  57     nd_uint8_t max_length;
  58     nd_uint8_t zero;
  59     nd_ipv4 prefix;
  60     nd_uint32_t as;
  61 } rpki_rtr_pdu_ipv4_prefix;
  62
  63 /*
  64  * IPv6 Prefix PDU.
  65  */
  66 typedef struct rpki_rtr_pdu_ipv6_prefix_ {
  67     rpki_rtr_pdu pdu_header;
  68     nd_uint8_t flags;
  69     nd_uint8_t prefix_length;
  70     nd_uint8_t max_length;
  71     nd_uint8_t zero;
  72     nd_ipv6 prefix;
  73     nd_uint32_t as;
  74 } rpki_rtr_pdu_ipv6_prefix;
  75
  76 /*
  77  * Error report PDU.
  78  */
  79 typedef struct rpki_rtr_pdu_error_report_ {
  80     rpki_rtr_pdu pdu_header;
  81     nd_uint32_t encapsulated_pdu_length; /* Encapsulated PDU length */
  82     /* Copy of Erroneous PDU (variable, optional) */
  83     /* Length of Error Text (4 octets in network byte order) */
  84     /* Arbitrary Text of Error Diagnostic Message (variable, optional) */
  85 } rpki_rtr_pdu_error_report;
  86
  87 /*
  88  * PDU type codes
  89  */
  90 #define RPKI_RTR_SERIAL_NOTIFY_PDU      0
  91 #define RPKI_RTR_SERIAL_QUERY_PDU       1
  92 #define RPKI_RTR_RESET_QUERY_PDU        2
  93 #define RPKI_RTR_CACHE_RESPONSE_PDU     3
  94 #define RPKI_RTR_IPV4_PREFIX_PDU        4
  95 #define RPKI_RTR_IPV6_PREFIX_PDU        6
  96 #define RPKI_RTR_END_OF_DATA_PDU        7
  97 #define RPKI_RTR_CACHE_RESET_PDU        8
  98 #define RPKI_RTR_ERROR_REPORT_PDU       10
  99
 100 static const struct tok rpki_rtr_pdu_values[] = {
 101     { RPKI_RTR_SERIAL_NOTIFY_PDU, "Serial Notify" },
 102     { RPKI_RTR_SERIAL_QUERY_PDU, "Serial Query" },
 103     { RPKI_RTR_RESET_QUERY_PDU, "Reset Query" },
 104     { RPKI_RTR_CACHE_RESPONSE_PDU, "Cache Response" },
 105     { RPKI_RTR_IPV4_PREFIX_PDU, "IPV4 Prefix" },
 106     { RPKI_RTR_IPV6_PREFIX_PDU, "IPV6 Prefix" },
 107     { RPKI_RTR_END_OF_DATA_PDU, "End of Data" },
 108     { RPKI_RTR_CACHE_RESET_PDU, "Cache Reset" },
 109     { RPKI_RTR_ERROR_REPORT_PDU, "Error Report" },
 110     { 0, NULL}
 111 };
 112
 113 static const struct tok rpki_rtr_error_codes[] = {
 114     { 0, "Corrupt Data" },
 115     { 1, "Internal Error" },
 116     { 2, "No Data Available" },
 117     { 3, "Invalid Request" },
 118     { 4, "Unsupported Protocol Version" },
 119     { 5, "Unsupported PDU Type" },
 120     { 6, "Withdrawal of Unknown Record" },
 121     { 7, "Duplicate Announcement Received" },
 122     { 0, NULL}
 123 };
 124
 125 /*
 126  * Build a indentation string for a given indentation level.
 127  * XXX this should be really in util.c
 128  */
 129 static char *
 130 indent_string (u_int indent)
 131 {
 132     static char buf[20];
 133     u_int idx;
 134
 135     idx = 0;
 136     buf[idx] = '\0';
 137
 138     /*
 139      * Does the static buffer fit ?
 140      */
 141     if (sizeof(buf) < ((indent/8) + (indent %8) + 2)) {
 142         return buf;
 143     }
 144
 145     /*
 146      * Heading newline.
 147      */
 148     buf[idx] = '\n';
 149     idx++;
 150
 151     while (indent >= 8) {
 152         buf[idx] = '\t';
 153         idx++;
 154         indent -= 8;
 155     }
 156
 157     while (indent > 0) {
 158         buf[idx] = ' ';
 159         idx++;
 160         indent--;
 161     }
 162
 163     /*
 164      * Trailing zero.
 165      */
 166     buf[idx] = '\0';
 167
 168     return buf;
 169 }
 170
 171 /*
 172  * Print a single PDU.
 173  */
 174 static u_int
 175 rpki_rtr_pdu_print(netdissect_options *ndo, const u_char *tptr, const u_int len,
 176                    const u_char recurse, const u_int indent)
 177 {
 178     const rpki_rtr_pdu *pdu_header;
 179     u_int pdu_type, pdu_len, hexdump;
 180     const u_char *msg;
 181
 182     /* Protocol Version */
 183     if (GET_U_1(tptr) != 0) {
 184         /* Skip the rest of the input buffer because even if this is
 185          * a well-formed PDU of a future RPKI-Router protocol version
 186          * followed by a well-formed PDU of RPKI-Router protocol
 187          * version 0, there is no way to know exactly how to skip the
 188          * current PDU.
 189          */
 190         ND_PRINT("%sRPKI-RTRv%u (unknown)", indent_string(8), GET_U_1(tptr));
 191         return len;
 192     }
 193     if (len < sizeof(rpki_rtr_pdu)) {
 194         ND_PRINT("(%u bytes is too few to decode)", len);
 195         goto invalid;
 196     }
 197     ND_TCHECK_LEN(tptr, sizeof(rpki_rtr_pdu));
 198     pdu_header = (const rpki_rtr_pdu *)tptr;
 199     pdu_type = GET_U_1(pdu_header->pdu_type);
 200     pdu_len = GET_BE_U_4(pdu_header->length);
 201     /* Do not check bounds with pdu_len yet, do it in the case blocks
 202      * below to make it possible to decode at least the beginning of
 203      * a truncated Error Report PDU or a truncated encapsulated PDU.
 204      */
 205     hexdump = FALSE;
 206
 207     ND_PRINT("%sRPKI-RTRv%u, %s PDU (%u), length: %u",
 208            indent_string(8),
 209            GET_U_1(pdu_header->version),
 210            tok2str(rpki_rtr_pdu_values, "Unknown", pdu_type),
 211            pdu_type, pdu_len);
 212     if (pdu_len < sizeof(rpki_rtr_pdu) || pdu_len > len)
 213         goto invalid;
 214
 215     switch (pdu_type) {
 216
 217         /*
 218          * The following PDUs share the message format.
 219          */
 220     case RPKI_RTR_SERIAL_NOTIFY_PDU:
 221     case RPKI_RTR_SERIAL_QUERY_PDU:
 222     case RPKI_RTR_END_OF_DATA_PDU:
 223         if (pdu_len != sizeof(rpki_rtr_pdu) + 4)
 224             goto invalid;
 225         msg = (const u_char *)(pdu_header + 1);
 226         ND_PRINT("%sSession ID: 0x%04x, Serial: %u",
 227                indent_string(indent+2),
 228                GET_BE_U_2(pdu_header->u.session_id),
 229                GET_BE_U_4(msg));
 230         break;
 231
 232         /*
 233          * The following PDUs share the message format.
 234          */
 235     case RPKI_RTR_RESET_QUERY_PDU:
 236     case RPKI_RTR_CACHE_RESET_PDU:
 237         if (pdu_len != sizeof(rpki_rtr_pdu))
 238             goto invalid;
 239         /* no additional boundary to check */
 240
 241         /*
 242          * Zero payload PDUs.
 243          */
 244         break;
 245
 246     case RPKI_RTR_CACHE_RESPONSE_PDU:
 247         if (pdu_len != sizeof(rpki_rtr_pdu))
 248             goto invalid;
 249         /* no additional boundary to check */
 250         ND_PRINT("%sSession ID: 0x%04x",
 251                indent_string(indent+2),
 252                GET_BE_U_2(pdu_header->u.session_id));
 253         break;
 254
 255     case RPKI_RTR_IPV4_PREFIX_PDU:
 256         {
 257             const rpki_rtr_pdu_ipv4_prefix *pdu;
 258
 259             if (pdu_len != sizeof(rpki_rtr_pdu_ipv4_prefix))
 260                 goto invalid;
 261             pdu = (const rpki_rtr_pdu_ipv4_prefix *)tptr;
 262             ND_PRINT("%sIPv4 Prefix %s/%u-%u, origin-as %u, flags 0x%02x",
 263                    indent_string(indent+2),
 264                    GET_IPADDR_STRING(pdu->prefix),
 265                    GET_U_1(pdu->prefix_length), GET_U_1(pdu->max_length),
 266                    GET_BE_U_4(pdu->as), GET_U_1(pdu->flags));
 267         }
 268         break;
 269
 270     case RPKI_RTR_IPV6_PREFIX_PDU:
 271         {
 272             const rpki_rtr_pdu_ipv6_prefix *pdu;
 273
 274             if (pdu_len != sizeof(rpki_rtr_pdu_ipv6_prefix))
 275                 goto invalid;
 276             pdu = (const rpki_rtr_pdu_ipv6_prefix *)tptr;
 277             ND_PRINT("%sIPv6 Prefix %s/%u-%u, origin-as %u, flags 0x%02x",
 278                    indent_string(indent+2),
 279                    GET_IP6ADDR_STRING(pdu->prefix),
 280                    GET_U_1(pdu->prefix_length), GET_U_1(pdu->max_length),
 281                    GET_BE_U_4(pdu->as), GET_U_1(pdu->flags));
 282         }
 283         break;
 284
 285     case RPKI_RTR_ERROR_REPORT_PDU:
 286         {
 287             const rpki_rtr_pdu_error_report *pdu;
 288             u_int encapsulated_pdu_length, text_length, tlen, error_code;
 289
 290             tlen = sizeof(rpki_rtr_pdu);
 291             /* Do not test for the "Length of Error Text" data element yet. */
 292             if (pdu_len < tlen + 4)
 293                 goto invalid;
 294             ND_TCHECK_LEN(tptr, tlen + 4);
 295             /* Safe up to and including the "Length of Encapsulated PDU"
 296              * data element, more data elements may be present.
 297              */
 298             pdu = (const rpki_rtr_pdu_error_report *)tptr;
 299             encapsulated_pdu_length = GET_BE_U_4(pdu->encapsulated_pdu_length);
 300             tlen += 4;
 301
 302             error_code = GET_BE_U_2(pdu->pdu_header.u.error_code);
 303             ND_PRINT("%sError code: %s (%u), Encapsulated PDU length: %u",
 304                    indent_string(indent+2),
 305                    tok2str(rpki_rtr_error_codes, "Unknown", error_code),
 306                    error_code, encapsulated_pdu_length);
 307
 308             if (encapsulated_pdu_length) {
 309                 /* Section 5.10 of RFC 6810 says:
 310                  * "An Error Report PDU MUST NOT be sent for an Error Report PDU."
 311                  *
 312                  * However, as far as the protocol encoding goes Error Report PDUs can
 313                  * happen to be nested in each other, however many times, in which case
 314                  * the decoder should still print such semantically incorrect PDUs.
 315                  *
 316                  * That said, "the Erroneous PDU field MAY be truncated" (ibid), thus
 317                  * to keep things simple this implementation decodes only the two
 318                  * outermost layers of PDUs and makes bounds checks in the outer and
 319                  * the inner PDU independently.
 320                  */
 321                 if (pdu_len < tlen + encapsulated_pdu_length)
 322                     goto invalid;
 323                 if (! recurse) {
 324                     ND_TCHECK_LEN(tptr, tlen + encapsulated_pdu_length);
 325                 }
 326                 else {
 327                     ND_PRINT("%s-----encapsulated PDU-----", indent_string(indent+4));
 328                     rpki_rtr_pdu_print(ndo, tptr + tlen,
 329                         encapsulated_pdu_length, 0, indent + 2);
 330                 }
 331                 tlen += encapsulated_pdu_length;
 332             }
 333
 334             if (pdu_len < tlen + 4)
 335                 goto invalid;
 336             ND_TCHECK_LEN(tptr, tlen + 4);
 337             /* Safe up to and including the "Length of Error Text" data element,
 338              * one more data element may be present.
 339              */
 340
 341             /*
 342              * Extract, trail-zero and print the Error message.
 343              */
 344             text_length = GET_BE_U_4(tptr + tlen);
 345             tlen += 4;
 346
 347             if (text_length) {
 348                 if (pdu_len < tlen + text_length)
 349                     goto invalid;
 350                 /* nd_printn() makes the bounds check */
 351                 ND_PRINT("%sError text: ", indent_string(indent+2));
 352                 (void)nd_printn(ndo, tptr + tlen, text_length, NULL);
 353             }
 354         }
 355         break;
 356
 357     default:
 358         ND_TCHECK_LEN(tptr, pdu_len);
 359
 360         /*
 361          * Unknown data, please hexdump.
 362          */
 363         hexdump = TRUE;
 364     }
 365
 366     /* do we also want to see a hex dump ? */
 367     if (ndo->ndo_vflag > 1 || (ndo->ndo_vflag && hexdump)) {
 368         print_unknown_data(ndo,tptr,"\n\t  ", pdu_len);
 369     }
 370     return pdu_len;
 371
 372 invalid:
 373     nd_print_invalid(ndo);
 374     ND_TCHECK_LEN(tptr, len);
 375     return len;
 376 }
 377
 378 void
 379 rpki_rtr_print(netdissect_options *ndo, const u_char *pptr, u_int len)
 380 {
 381     ndo->ndo_protocol = "rpki_rtr";
 382     if (!ndo->ndo_vflag) {
 383         ND_PRINT(", RPKI-RTR");
 384         return;
 385     }
 386     while (len) {
 387         u_int pdu_len = rpki_rtr_pdu_print(ndo, pptr, len, 1, 8);
 388         len -= pdu_len;
 389         pptr += pdu_len;
 390     }
 391 }