The Tcpdump Group git mirrors - tcpdump/blob - 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 #include <string.h>
  29
  30 #include "netdissect.h"
  31 #include "extract.h"
  32 #include "addrtoname.h"
  33
  34
  35 /*
  36  * RPKI/Router PDU header
  37  *
  38  * Here's what the PDU header looks like.
  39  * The length does include the version and length fields.
  40  */
  41 typedef struct rpki_rtr_pdu_ {
  42     u_char version;             /* Version number */
  43     u_char pdu_type;            /* PDU type */
  44     union {
  45         u_char session_id[2];   /* Session id */
  46         u_char error_code[2];   /* Error code */
  47     } u;
  48     u_char length[4];
  49 } rpki_rtr_pdu;
  50
  51 /*
  52  * IPv4 Prefix PDU.
  53  */
  54 typedef struct rpki_rtr_pdu_ipv4_prefix_ {
  55     rpki_rtr_pdu pdu_header;
  56     u_char flags;
  57     u_char prefix_length;
  58     u_char max_length;
  59     u_char zero;
  60     u_char prefix[4];
  61     u_char as[4];
  62 } rpki_rtr_pdu_ipv4_prefix;
  63
  64 /*
  65  * IPv6 Prefix PDU.
  66  */
  67 typedef struct rpki_rtr_pdu_ipv6_prefix_ {
  68     rpki_rtr_pdu pdu_header;
  69     u_char flags;
  70     u_char prefix_length;
  71     u_char max_length;
  72     u_char zero;
  73     u_char prefix[16];
  74     u_char as[4];
  75 } rpki_rtr_pdu_ipv6_prefix;
  76
  77 /*
  78  * Error report PDU.
  79  */
  80 typedef struct rpki_rtr_pdu_error_report_ {
  81     rpki_rtr_pdu pdu_header;
  82     u_char encapsulated_pdu_length[4]; /* Encapsulated PDU length */
  83     /* Copy of Erroneous PDU (variable, optional) */
  84     /* Length of Error Text (4 octets in network byte order) */
  85     /* Arbitrary Text of Error Diagnostic Message (variable, optional) */
  86 } rpki_rtr_pdu_error_report;
  87
  88 /*
  89  * PDU type codes
  90  */
  91 #define RPKI_RTR_SERIAL_NOTIFY_PDU      0
  92 #define RPKI_RTR_SERIAL_QUERY_PDU       1
  93 #define RPKI_RTR_RESET_QUERY_PDU        2
  94 #define RPKI_RTR_CACHE_RESPONSE_PDU     3
  95 #define RPKI_RTR_IPV4_PREFIX_PDU        4
  96 #define RPKI_RTR_IPV6_PREFIX_PDU        6
  97 #define RPKI_RTR_END_OF_DATA_PDU        7
  98 #define RPKI_RTR_CACHE_RESET_PDU        8
  99 #define RPKI_RTR_ERROR_REPORT_PDU       10
 100
 101 static const struct tok rpki_rtr_pdu_values[] = {
 102     { RPKI_RTR_SERIAL_NOTIFY_PDU, "Serial Notify" },
 103     { RPKI_RTR_SERIAL_QUERY_PDU, "Serial Query" },
 104     { RPKI_RTR_RESET_QUERY_PDU, "Reset Query" },
 105     { RPKI_RTR_CACHE_RESPONSE_PDU, "Cache Response" },
 106     { RPKI_RTR_IPV4_PREFIX_PDU, "IPV4 Prefix" },
 107     { RPKI_RTR_IPV6_PREFIX_PDU, "IPV6 Prefix" },
 108     { RPKI_RTR_END_OF_DATA_PDU, "End of Data" },
 109     { RPKI_RTR_CACHE_RESET_PDU, "Cache Reset" },
 110     { RPKI_RTR_ERROR_REPORT_PDU, "Error Report" },
 111     { 0, NULL}
 112 };
 113
 114 static const struct tok rpki_rtr_error_codes[] = {
 115     { 0, "Corrupt Data" },
 116     { 1, "Internal Error" },
 117     { 2, "No Data Available" },
 118     { 3, "Invalid Request" },
 119     { 4, "Unsupported Protocol Version" },
 120     { 5, "Unsupported PDU Type" },
 121     { 6, "Withdrawal of Unknown Record" },
 122     { 7, "Duplicate Announcement Received" },
 123     { 0, NULL}
 124 };
 125
 126 /*
 127  * Build a indentation string for a given indentation level.
 128  * XXX this should be really in util.c
 129  */
 130 static char *
 131 indent_string (u_int indent)
 132 {
 133     static char buf[20];
 134     u_int idx;
 135
 136     idx = 0;
 137     buf[idx] = '\0';
 138
 139     /*
 140      * Does the static buffer fit ?
 141      */
 142     if (sizeof(buf) < ((indent/8) + (indent %8) + 2)) {
 143         return buf;
 144     }
 145
 146     /*
 147      * Heading newline.
 148      */
 149     buf[idx] = '\n';
 150     idx++;
 151
 152     while (indent >= 8) {
 153         buf[idx] = '\t';
 154         idx++;
 155         indent -= 8;
 156     }
 157
 158     while (indent > 0) {
 159         buf[idx] = ' ';
 160         idx++;
 161         indent--;
 162     }
 163
 164     /*
 165      * Trailing zero.
 166      */
 167     buf[idx] = '\0';
 168
 169     return buf;
 170 }
 171
 172 /*
 173  * Print a single PDU.
 174  */
 175 static u_int
 176 rpki_rtr_pdu_print(netdissect_options *ndo, const u_char *tptr, const u_int len,
 177                    const u_char recurse, const u_int indent)
 178 {
 179     const rpki_rtr_pdu *pdu_header;
 180     u_int pdu_type, pdu_len, hexdump;
 181     const u_char *msg;
 182
 183     /* Protocol Version */
 184     ND_TCHECK_1(tptr);
 185     if (GET_U_1(tptr) != 0) {
 186         /* Skip the rest of the input buffer because even if this is
 187          * a well-formed PDU of a future RPKI-Router protocol version
 188          * followed by a well-formed PDU of RPKI-Router protocol
 189          * version 0, there is no way to know exactly how to skip the
 190          * current PDU.
 191          */
 192         ND_PRINT("%sRPKI-RTRv%u (unknown)", indent_string(8), GET_U_1(tptr));
 193         return len;
 194     }
 195     if (len < sizeof(rpki_rtr_pdu)) {
 196         ND_PRINT("(%u bytes is too few to decode)", len);
 197         goto invalid;
 198     }
 199     ND_TCHECK_LEN(tptr, sizeof(rpki_rtr_pdu));
 200     pdu_header = (const rpki_rtr_pdu *)tptr;
 201     pdu_type = pdu_header->pdu_type;
 202     pdu_len = GET_BE_U_4(pdu_header->length);
 203     /* Do not check bounds with pdu_len yet, do it in the case blocks
 204      * below to make it possible to decode at least the beginning of
 205      * a truncated Error Report PDU or a truncated encapsulated PDU.
 206      */
 207     hexdump = FALSE;
 208
 209     ND_PRINT("%sRPKI-RTRv%u, %s PDU (%u), length: %u",
 210            indent_string(8),
 211            pdu_header->version,
 212            tok2str(rpki_rtr_pdu_values, "Unknown", pdu_type),
 213            pdu_type, pdu_len);
 214     if (pdu_len < sizeof(rpki_rtr_pdu) || pdu_len > len)
 215         goto invalid;
 216
 217     switch (pdu_type) {
 218
 219         /*
 220          * The following PDUs share the message format.
 221          */
 222     case RPKI_RTR_SERIAL_NOTIFY_PDU:
 223     case RPKI_RTR_SERIAL_QUERY_PDU:
 224     case RPKI_RTR_END_OF_DATA_PDU:
 225         if (pdu_len != sizeof(rpki_rtr_pdu) + 4)
 226             goto invalid;
 227         ND_TCHECK_LEN(tptr, pdu_len);
 228         msg = (const u_char *)(pdu_header + 1);
 229         ND_PRINT("%sSession ID: 0x%04x, Serial: %u",
 230                indent_string(indent+2),
 231                GET_BE_U_2(pdu_header->u.session_id),
 232                GET_BE_U_4(msg));
 233         break;
 234
 235         /*
 236          * The following PDUs share the message format.
 237          */
 238     case RPKI_RTR_RESET_QUERY_PDU:
 239     case RPKI_RTR_CACHE_RESET_PDU:
 240         if (pdu_len != sizeof(rpki_rtr_pdu))
 241             goto invalid;
 242         /* no additional boundary to check */
 243
 244         /*
 245          * Zero payload PDUs.
 246          */
 247         break;
 248
 249     case RPKI_RTR_CACHE_RESPONSE_PDU:
 250         if (pdu_len != sizeof(rpki_rtr_pdu))
 251             goto invalid;
 252         /* no additional boundary to check */
 253         ND_PRINT("%sSession ID: 0x%04x",
 254                indent_string(indent+2),
 255                GET_BE_U_2(pdu_header->u.session_id));
 256         break;
 257
 258     case RPKI_RTR_IPV4_PREFIX_PDU:
 259         {
 260             const rpki_rtr_pdu_ipv4_prefix *pdu;
 261
 262             if (pdu_len != sizeof(rpki_rtr_pdu) + 12)
 263                 goto invalid;
 264             ND_TCHECK_LEN(tptr, pdu_len);
 265             pdu = (const rpki_rtr_pdu_ipv4_prefix *)tptr;
 266             ND_PRINT("%sIPv4 Prefix %s/%u-%u, origin-as %u, flags 0x%02x",
 267                    indent_string(indent+2),
 268                    ipaddr_string(ndo, pdu->prefix),
 269                    pdu->prefix_length, pdu->max_length,
 270                    GET_BE_U_4(pdu->as), pdu->flags);
 271         }
 272         break;
 273
 274     case RPKI_RTR_IPV6_PREFIX_PDU:
 275         {
 276             const rpki_rtr_pdu_ipv6_prefix *pdu;
 277
 278             if (pdu_len != sizeof(rpki_rtr_pdu) + 24)
 279                 goto invalid;
 280             ND_TCHECK_LEN(tptr, pdu_len);
 281             pdu = (const rpki_rtr_pdu_ipv6_prefix *)tptr;
 282             ND_PRINT("%sIPv6 Prefix %s/%u-%u, origin-as %u, flags 0x%02x",
 283                    indent_string(indent+2),
 284                    ip6addr_string(ndo, pdu->prefix),
 285                    pdu->prefix_length, pdu->max_length,
 286                    GET_BE_U_4(pdu->as), pdu->flags);
 287         }
 288         break;
 289
 290     case RPKI_RTR_ERROR_REPORT_PDU:
 291         {
 292             const rpki_rtr_pdu_error_report *pdu;
 293             u_int encapsulated_pdu_length, text_length, tlen, error_code;
 294
 295             tlen = sizeof(rpki_rtr_pdu);
 296             /* Do not test for the "Length of Error Text" data element yet. */
 297             if (pdu_len < tlen + 4)
 298                 goto invalid;
 299             ND_TCHECK_LEN(tptr, tlen + 4);
 300             /* Safe up to and including the "Length of Encapsulated PDU"
 301              * data element, more data elements may be present.
 302              */
 303             pdu = (const rpki_rtr_pdu_error_report *)tptr;
 304             encapsulated_pdu_length = GET_BE_U_4(pdu->encapsulated_pdu_length);
 305             tlen += 4;
 306
 307             error_code = GET_BE_U_2(pdu->pdu_header.u.error_code);
 308             ND_PRINT("%sError code: %s (%u), Encapsulated PDU length: %u",
 309                    indent_string(indent+2),
 310                    tok2str(rpki_rtr_error_codes, "Unknown", error_code),
 311                    error_code, encapsulated_pdu_length);
 312
 313             if (encapsulated_pdu_length) {
 314                 /* Section 5.10 of RFC 6810 says:
 315                  * "An Error Report PDU MUST NOT be sent for an Error Report PDU."
 316                  *
 317                  * However, as far as the protocol encoding goes Error Report PDUs can
 318                  * happen to be nested in each other, however many times, in which case
 319                  * the decoder should still print such semantically incorrect PDUs.
 320                  *
 321                  * That said, "the Erroneous PDU field MAY be truncated" (ibid), thus
 322                  * to keep things simple this implementation decodes only the two
 323                  * outermost layers of PDUs and makes bounds checks in the outer and
 324                  * the inner PDU independently.
 325                  */
 326                 if (pdu_len < tlen + encapsulated_pdu_length)
 327                     goto invalid;
 328                 if (! recurse) {
 329                     ND_TCHECK_LEN(tptr, tlen + encapsulated_pdu_length);
 330                 }
 331                 else {
 332                     ND_PRINT("%s-----encapsulated PDU-----", indent_string(indent+4));
 333                     rpki_rtr_pdu_print(ndo, tptr + tlen,
 334                         encapsulated_pdu_length, 0, indent + 2);
 335                 }
 336                 tlen += encapsulated_pdu_length;
 337             }
 338
 339             if (pdu_len < tlen + 4)
 340                 goto invalid;
 341             ND_TCHECK_LEN(tptr, tlen + 4);
 342             /* Safe up to and including the "Length of Error Text" data element,
 343              * one more data element may be present.
 344              */
 345
 346             /*
 347              * Extract, trail-zero and print the Error message.
 348              */
 349             text_length = GET_BE_U_4(tptr + tlen);
 350             tlen += 4;
 351
 352             if (text_length) {
 353                 if (pdu_len < tlen + text_length)
 354                     goto invalid;
 355                 /* nd_printn() makes the bounds check */
 356                 ND_PRINT("%sError text: ", indent_string(indent+2));
 357                 if (nd_printn(ndo, tptr + tlen, text_length, ndo->ndo_snapend))
 358                         goto trunc;
 359             }
 360         }
 361         break;
 362
 363     default:
 364         ND_TCHECK_LEN(tptr, pdu_len);
 365
 366         /*
 367          * Unknown data, please hexdump.
 368          */
 369         hexdump = TRUE;
 370     }
 371
 372     /* do we also want to see a hex dump ? */
 373     if (ndo->ndo_vflag > 1 || (ndo->ndo_vflag && hexdump)) {
 374         print_unknown_data(ndo,tptr,"\n\t  ", pdu_len);
 375     }
 376     return pdu_len;
 377
 378 invalid:
 379     nd_print_invalid(ndo);
 380     ND_TCHECK_LEN(tptr, len);
 381     return len;
 382 trunc:
 383     nd_print_trunc(ndo);
 384     return len;
 385 }
 386
 387 void
 388 rpki_rtr_print(netdissect_options *ndo, const u_char *pptr, u_int len)
 389 {
 390     ndo->ndo_protocol = "rpki_rtr";
 391     if (!ndo->ndo_vflag) {
 392         ND_PRINT(", RPKI-RTR");
 393         return;
 394     }
 395     while (len) {
 396         u_int pdu_len = rpki_rtr_pdu_print(ndo, pptr, len, 1, 8);
 397         len -= pdu_len;
 398         pptr += pdu_len;
 399     }
 400 }