/* ipfix.c * * Wiretap Library * Copyright (c) 1998 by Gilbert Ramirez * * File format support for ipfix file format * Copyright (c) 2010 by Hadriel Kaplan * with generous copying from other wiretaps, such as pcapng * * SPDX-License-Identifier: GPL-2.0-or-later */ /* File format reference: * RFC 5655 and 5101 * https://tools.ietf.org/rfc/rfc5655 * https://tools.ietf.org/rfc/rfc5101 * * This wiretap is for an ipfix file format reader, per RFC 5655/5101. * All "records" in the file are IPFIX messages, beginning with an IPFIX * message header of 16 bytes as follows from RFC 5101: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version Number | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Export Time | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Observation Domain ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure F: IPFIX Message Header Format * which is then followed by one or more "Sets": Data Sets, Template Sets, * and Options Template Sets. Each Set then has one or more Records in * it. * * All IPFIX files are recorded in big-endian form (network byte order), * per the RFCs. That means if we're on a little-endian system, all * hell will break loose if we don't g_ntohX. * * Since wireshark already has an IPFIX dissector (implemented in * packet-netflow.c), this reader will just set that dissector upon * reading each message. Thus, an IPFIX Message is treated as a packet * as far as the dissector is concerned. */ #include "config.h" #define WS_LOG_DOMAIN LOG_DOMAIN_WIRETAP #include "ipfix.h" #include #include #include "wtap-int.h" #include "file_wrappers.h" #include #include #define RECORDS_FOR_IPFIX_CHECK 20 static bool ipfix_read(wtap *wth, wtap_rec *rec, Buffer *buf, int *err, char **err_info, int64_t *data_offset); static bool ipfix_seek_read(wtap *wth, int64_t seek_off, wtap_rec *rec, Buffer *buf, int *err, char **err_info); #define IPFIX_VERSION 10 /* ipfix: message header */ typedef struct ipfix_message_header_s { uint16_t version; uint16_t message_length; uint32_t export_time_secs; uint32_t sequence_number; uint32_t observation_id; /* might be 0 for none */ /* x bytes msg_body */ } ipfix_message_header_t; #define IPFIX_MSG_HDR_SIZE 16 /* ipfix: common Set header for every Set type */ typedef struct ipfix_set_header_s { uint16_t set_type; uint16_t set_length; /* x bytes set_body */ } ipfix_set_header_t; #define IPFIX_SET_HDR_SIZE 4 static int ipfix_file_type_subtype = -1; void register_ipfix(void); /* Read IPFIX message header from file. Return true on success. Set *err to * 0 on EOF, any other value for "real" errors (EOF is ok, since return * value is still false) */ static bool ipfix_read_message_header(ipfix_message_header_t *pfx_hdr, FILE_T fh, int *err, char **err_info) { if (!wtap_read_bytes_or_eof(fh, pfx_hdr, IPFIX_MSG_HDR_SIZE, err, err_info)) return false; /* fix endianness, because IPFIX files are always big-endian */ pfx_hdr->version = g_ntohs(pfx_hdr->version); pfx_hdr->message_length = g_ntohs(pfx_hdr->message_length); pfx_hdr->export_time_secs = g_ntohl(pfx_hdr->export_time_secs); pfx_hdr->sequence_number = g_ntohl(pfx_hdr->sequence_number); pfx_hdr->observation_id = g_ntohl(pfx_hdr->observation_id); /* is the version number one we expect? */ if (pfx_hdr->version != IPFIX_VERSION) { /* Not an ipfix file. */ *err = WTAP_ERR_BAD_FILE; *err_info = ws_strdup_printf("ipfix: wrong version %d", pfx_hdr->version); return false; } if (pfx_hdr->message_length < 16) { *err = WTAP_ERR_BAD_FILE; *err_info = ws_strdup_printf("ipfix: message length %u is too short", pfx_hdr->message_length); return false; } /* go back to before header */ if (file_seek(fh, 0 - IPFIX_MSG_HDR_SIZE, SEEK_CUR, err) == -1) { ws_debug("couldn't go back in file before header"); return false; } return true; } /* Read IPFIX message header from file and fill in the struct wtap_rec * for the packet, and, if that succeeds, read the packet data. * Return true on success. Set *err to 0 on EOF, any other value for "real" * errors (EOF is ok, since return value is still false). */ static bool ipfix_read_message(FILE_T fh, wtap_rec *rec, Buffer *buf, int *err, char **err_info) { ipfix_message_header_t msg_hdr; if (!ipfix_read_message_header(&msg_hdr, fh, err, err_info)) return false; /* * The maximum value of msg_hdr.message_length is 65535, which is * less than WTAP_MAX_PACKET_SIZE_STANDARD will ever be, so we don't need * to check it. */ rec->rec_type = REC_TYPE_PACKET; rec->block = wtap_block_create(WTAP_BLOCK_PACKET); rec->presence_flags = WTAP_HAS_TS; rec->rec_header.packet_header.len = msg_hdr.message_length; rec->rec_header.packet_header.caplen = msg_hdr.message_length; rec->ts.secs = msg_hdr.export_time_secs; rec->ts.nsecs = 0; return wtap_read_packet_bytes(fh, buf, msg_hdr.message_length, err, err_info); } /* classic wtap: open capture file. Return WTAP_OPEN_MINE on success, * WTAP_OPEN_NOT_MINE on normal failure like malformed format, * WTAP_OPEN_ERROR on bad error like file system */ wtap_open_return_val ipfix_open(wtap *wth, int *err, char **err_info) { int i, n, records_for_ipfix_check = RECORDS_FOR_IPFIX_CHECK; char *s; uint16_t checked_len; ipfix_message_header_t msg_hdr; ipfix_set_header_t set_hdr; ws_debug("opening file"); /* number of records to scan before deciding if this really is IPFIX */ if ((s = getenv("IPFIX_RECORDS_TO_CHECK")) != NULL) { if (ws_strtoi32(s, NULL, &n) && n > 0 && n < 101) { records_for_ipfix_check = n; } } /* * IPFIX is a little hard because there's no magic number; we look at * the first few records and see if they look enough like IPFIX * records. */ for (i = 0; i < records_for_ipfix_check; i++) { /* read first message header to check version */ if (!ipfix_read_message_header(&msg_hdr, wth->fh, err, err_info)) { ws_debug("couldn't read message header #%d with err code #%d (%s)", i, *err, *err_info); if (*err == WTAP_ERR_BAD_FILE) { *err = 0; /* not actually an error in this case */ g_free(*err_info); *err_info = NULL; return WTAP_OPEN_NOT_MINE; } if (*err != 0 && *err != WTAP_ERR_SHORT_READ) return WTAP_OPEN_ERROR; /* real failure */ /* else it's EOF */ if (i < 1) { /* we haven't seen enough to prove this is a ipfix file */ return WTAP_OPEN_NOT_MINE; } /* * If we got here, it's EOF and we haven't yet seen anything * that doesn't look like an IPFIX record - i.e. everything * we've seen looks like an IPFIX record - so we assume this * is an IPFIX file. */ break; } if (file_seek(wth->fh, IPFIX_MSG_HDR_SIZE, SEEK_CUR, err) == -1) { ws_debug("failed seek to next message in file, %d bytes away", msg_hdr.message_length); return WTAP_OPEN_NOT_MINE; } checked_len = IPFIX_MSG_HDR_SIZE; /* check each Set in IPFIX Message for sanity */ while (checked_len < msg_hdr.message_length) { if (!wtap_read_bytes(wth->fh, &set_hdr, IPFIX_SET_HDR_SIZE, err, err_info)) { if (*err == WTAP_ERR_SHORT_READ) { /* Not a valid IPFIX Set, so not an IPFIX file. */ ws_debug("error %d reading set", *err); return WTAP_OPEN_NOT_MINE; } /* A real I/O error; fail. */ return WTAP_OPEN_ERROR; } set_hdr.set_length = g_ntohs(set_hdr.set_length); if ((set_hdr.set_length < IPFIX_SET_HDR_SIZE) || ((set_hdr.set_length + checked_len) > msg_hdr.message_length)) { ws_debug("found invalid set_length of %d", set_hdr.set_length); return WTAP_OPEN_NOT_MINE; } if (file_seek(wth->fh, set_hdr.set_length - IPFIX_SET_HDR_SIZE, SEEK_CUR, err) == -1) { ws_debug("failed seek to next set in file, %d bytes away", set_hdr.set_length - IPFIX_SET_HDR_SIZE); return WTAP_OPEN_ERROR; } checked_len += set_hdr.set_length; } } /* go back to beginning of file */ if (file_seek (wth->fh, 0, SEEK_SET, err) != 0) { return WTAP_OPEN_ERROR; } /* all's good, this is a IPFIX file */ wth->file_encap = WTAP_ENCAP_RAW_IPFIX; wth->snapshot_length = 0; wth->file_tsprec = WTAP_TSPREC_SEC; wth->subtype_read = ipfix_read; wth->subtype_seek_read = ipfix_seek_read; wth->file_type_subtype = ipfix_file_type_subtype; /* * Add an IDB; we don't know how many interfaces were * involved, so we just say one interface, about which * we only know the link-layer type, snapshot length, * and time stamp resolution. */ wtap_add_generated_idb(wth); return WTAP_OPEN_MINE; } /* classic wtap: read packet */ static bool ipfix_read(wtap *wth, wtap_rec *rec, Buffer *buf, int *err, char **err_info, int64_t *data_offset) { *data_offset = file_tell(wth->fh); ws_debug("offset is initially %" PRId64, *data_offset); if (!ipfix_read_message(wth->fh, rec, buf, err, err_info)) { ws_debug("couldn't read message header with code: %d\n, and error '%s'", *err, *err_info); return false; } return true; } /* classic wtap: seek to file position and read packet */ static bool ipfix_seek_read(wtap *wth, int64_t seek_off, wtap_rec *rec, Buffer *buf, int *err, char **err_info) { /* seek to the right file position */ if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1) { ws_debug("couldn't read message header with code: %d\n, and error '%s'", *err, *err_info); return false; /* Seek error */ } ws_debug("reading at offset %" PRIu64, seek_off); if (!ipfix_read_message(wth->random_fh, rec, buf, err, err_info)) { ws_debug("couldn't read message header"); if (*err == 0) *err = WTAP_ERR_SHORT_READ; return false; } return true; } static const struct supported_block_type ipfix_blocks_supported[] = { /* * We support packet blocks, with no comments or other options. */ { WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED } }; static const struct file_type_subtype_info ipfix_info = { "IPFIX File Format", "ipfix", "pfx", "ipfix", false, BLOCKS_SUPPORTED(ipfix_blocks_supported), NULL, NULL, NULL }; void register_ipfix(void) { ipfix_file_type_subtype = wtap_register_file_type_subtype(&ipfix_info); /* * Register name for backwards compatibility with the * wtap_filetypes table in Lua. */ wtap_register_backwards_compatibility_lua_name("IPFIX", ipfix_file_type_subtype); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */