/* capsa.c * * Wiretap Library * Copyright (c) 1998 by Gilbert Ramirez * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include "capsa.h" #include #include "wtap-int.h" #include "file_wrappers.h" #include /* * A file begins with a header containing: * * a 4-byte magic number, with 'c', 'p', 's', 'e'; * * either a 2-byte little-endian "format indicator" (version number?), * or a 1-byte major version number followed by a 1-byte minor version * number, or a 1-byte "format indicator" followed by something else * that's always been 0; * * a 2-byte 0xe8 0x03 (1000 - a data rate? megabits/second?) * * 4 bytes of 0x01 0x00 0x01 0x00; * * either a 4-byte little-endian file size followed by 0x00 0x00 0x00 0x00 * or an 8-byte little-endian file size; * * a 4-byte little-endian packet count (in dns_error_of_udp, it exceeds?) * * a 4-byte little-endian number? * * hex 2c 01 c8 00 00 00 da 36 00 00 00 00 00 00; * * the same 4-byte little-endian number as above (yes, misaligned); * * 0x01 or 0x03; * * a bunch of 0s, up to an offset of 0x36d6; * * more stuff. * * Following that is a sequence of { record offset block, up to 200 records } * pairs. * * A record offset block has 1 byte with the value 0xfe, a sequence of * up to 200 4-byte little-endian record offsets, and 4 or more bytes * of unknown data, making the block 805 bytes long. * * The record offsets are offsets, from the beginning of the record offset * block (i.e., from the 0xfe byte), of the records following the block. */ /* Magic number in Capsa files. */ static const char capsa_magic[] = { 'c', 'p', 's', 'e' }; /* * Before each group of 200 or fewer records there's a block of frame * offsets, giving the offsets, from the beginning of that block minus * one(1), of the next N records. */ #define N_RECORDS_PER_GROUP 200 /* Capsa (format indicator 1) record header. */ struct capsarec_hdr { uint32_t unknown1; /* low-order 32 bits of a number? */ uint32_t unknown2; /* 0x00 0x00 0x00 0x00 */ uint32_t timestamplo; /* low-order 32 bits of the time stamp, in microseconds since January 1, 1970, 00:00:00 UTC */ uint32_t timestamphi; /* high-order 32 bits of the time stamp, in microseconds since January 1, 1970, 00:00:00 UTC */ uint16_t rec_len; /* length of record */ uint16_t incl_len; /* number of octets captured in file */ uint16_t orig_len; /* actual length of packet */ uint16_t unknown5; /* 0x00 0x00 */ uint8_t count1; /* count1*4 bytes after unknown8 */ uint8_t count2; /* count2*4 bytes after that */ uint16_t unknown7; /* 0x01 0x10 */ uint32_t unknown8; /* 0x00 0x00 0x00 0x00 or random numbers */ }; /* Packet Builder (format indicator 2) record header. */ struct pbrec_hdr { uint16_t rec_len; /* length of record */ uint16_t incl_len; /* number of octets captured in file */ uint16_t orig_len; /* actual length of packet */ uint16_t unknown1; uint16_t unknown2; uint16_t unknown3; uint32_t unknown4; uint32_t timestamplo; /* low-order 32 bits of the time stamp, in microseconds since January 1, 1970, 00:00:00 UTC */ uint32_t timestamphi; /* high-order 32 bits of the time stamp, in microseconds since January 1, 1970, 00:00:00 UTC */ uint32_t unknown5; uint32_t unknown6; }; typedef struct { uint16_t format_indicator; uint32_t number_of_frames; uint32_t frame_count; int64_t base_offset; uint32_t record_offsets[N_RECORDS_PER_GROUP]; } capsa_t; static bool capsa_read(wtap *wth, wtap_rec *rec, Buffer *buf, int *err, char **err_info, int64_t *data_offset); static bool capsa_seek_read(wtap *wth, int64_t seek_off, wtap_rec *rec, Buffer *buf, int *err, char **err_info); static int capsa_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec, Buffer *buf, int *err, char **err_info); static int capsa_file_type_subtype = -1; static int packet_builder_file_type_subtype = -1; void register_capsa(void); wtap_open_return_val capsa_open(wtap *wth, int *err, char **err_info) { char magic[sizeof capsa_magic]; uint16_t format_indicator; int file_type_subtype; uint32_t number_of_frames; capsa_t *capsa; /* Read in the string that should be at the start of a Capsa file */ if (!wtap_read_bytes(wth->fh, magic, sizeof magic, err, err_info)) { if (*err != WTAP_ERR_SHORT_READ) return WTAP_OPEN_ERROR; return WTAP_OPEN_NOT_MINE; } if (memcmp(magic, capsa_magic, sizeof capsa_magic) != 0) { return WTAP_OPEN_NOT_MINE; } /* Read the mysterious "format indicator" */ if (!wtap_read_bytes(wth->fh, &format_indicator, sizeof format_indicator, err, err_info)) return WTAP_OPEN_ERROR; format_indicator = GUINT16_FROM_LE(format_indicator); /* * Make sure it's a format we support. */ switch (format_indicator) { case 1: /* Capsa */ file_type_subtype = capsa_file_type_subtype; break; case 2: /* Packet Builder */ file_type_subtype = packet_builder_file_type_subtype; break; default: *err = WTAP_ERR_UNSUPPORTED; *err_info = ws_strdup_printf("capsa: format indicator %u unsupported", format_indicator); return WTAP_OPEN_ERROR; } /* * Link speed, in megabytes/second? */ if (!wtap_read_bytes(wth->fh, NULL, 2, err, err_info)) return WTAP_OPEN_ERROR; /* * Flags of some sort? Four 1-byte numbers, two of which are 1 * and two of which are zero? Two 2-byte numbers or flag fields, * both of which are 1? */ if (!wtap_read_bytes(wth->fh, NULL, 4, err, err_info)) return WTAP_OPEN_ERROR; /* * File size, in bytes. */ if (!wtap_read_bytes(wth->fh, NULL, 4, err, err_info)) return WTAP_OPEN_ERROR; /* * Zeroes? Or upper 4 bytes of file size? */ if (!wtap_read_bytes(wth->fh, NULL, 4, err, err_info)) return WTAP_OPEN_ERROR; /* * Count of packets. */ if (!wtap_read_bytes(wth->fh, &number_of_frames, sizeof number_of_frames, err, err_info)) return WTAP_OPEN_ERROR; number_of_frames = GUINT32_FROM_LE(number_of_frames); /* * Skip past what we think is file header. */ if (!file_seek(wth->fh, 0x44ef, SEEK_SET, err)) return WTAP_OPEN_ERROR; wth->file_type_subtype = file_type_subtype; capsa = g_new(capsa_t, 1); capsa->format_indicator = format_indicator; capsa->number_of_frames = number_of_frames; capsa->frame_count = 0; wth->priv = (void *)capsa; wth->subtype_read = capsa_read; wth->subtype_seek_read = capsa_seek_read; /* * XXX - we've never seen a Wi-Fi Capsa capture, so we don't * yet know how to handle them. */ wth->file_encap = WTAP_ENCAP_ETHERNET; wth->snapshot_length = 0; /* not available in header */ wth->file_tsprec = WTAP_TSPREC_USEC; /* * 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; } /* Read the next packet */ static bool capsa_read(wtap *wth, wtap_rec *rec, Buffer *buf, int *err, char **err_info, int64_t *data_offset) { capsa_t *capsa = (capsa_t *)wth->priv; uint32_t frame_within_block; int padbytes; if (capsa->frame_count == capsa->number_of_frames) { /* * No more frames left. Return an EOF. */ *err = 0; return false; } frame_within_block = capsa->frame_count % N_RECORDS_PER_GROUP; if (frame_within_block == 0) { /* * Here's a record offset block. * Get the offset of the block, and then skip the * first byte. */ capsa->base_offset = file_tell(wth->fh); if (!wtap_read_bytes(wth->fh, NULL, 1, err, err_info)) return false; /* * Now read the record offsets. */ if (!wtap_read_bytes(wth->fh, &capsa->record_offsets, sizeof capsa->record_offsets, err, err_info)) return false; /* * And finish processing all 805 bytes by skipping * the last 4 bytes. */ if (!wtap_read_bytes(wth->fh, NULL, 4, err, err_info)) return false; } *data_offset = capsa->base_offset + GUINT32_FROM_LE(capsa->record_offsets[frame_within_block]); if (!file_seek(wth->fh, *data_offset, SEEK_SET, err)) return false; padbytes = capsa_read_packet(wth, wth->fh, rec, buf, err, err_info); if (padbytes == -1) return false; /* * Skip over the padding, if any. */ if (padbytes != 0) { if (!wtap_read_bytes(wth->fh, NULL, padbytes, err, err_info)) return false; } capsa->frame_count++; return true; } static bool capsa_seek_read(wtap *wth, int64_t seek_off, wtap_rec *rec, Buffer *buf, int *err, char **err_info) { if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1) return false; if (capsa_read_packet(wth, wth->random_fh, rec, buf, err, err_info) == -1) { if (*err == 0) *err = WTAP_ERR_SHORT_READ; return false; } return true; } static int capsa_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec, Buffer *buf, int *err, char **err_info) { capsa_t *capsa = (capsa_t *)wth->priv; struct capsarec_hdr capsarec_hdr; struct pbrec_hdr pbrec_hdr; uint32_t rec_size; uint32_t packet_size; uint32_t orig_size; uint32_t header_size; uint64_t timestamp; /* Read record header. */ switch (capsa->format_indicator) { case 1: if (!wtap_read_bytes_or_eof(fh, &capsarec_hdr, sizeof capsarec_hdr, err, err_info)) return -1; rec_size = GUINT16_FROM_LE(capsarec_hdr.rec_len); orig_size = GUINT16_FROM_LE(capsarec_hdr.orig_len); packet_size = GUINT16_FROM_LE(capsarec_hdr.incl_len); header_size = sizeof capsarec_hdr; timestamp = (((uint64_t)GUINT32_FROM_LE(capsarec_hdr.timestamphi))<<32) + GUINT32_FROM_LE(capsarec_hdr.timestamplo); /* * OK, the rest of this is variable-length. * We skip: (count1+count2)*4 bytes. * XXX - what is that? Measured statistics? * Calculated statistics? */ if (!wtap_read_bytes(fh, NULL, (capsarec_hdr.count1 + capsarec_hdr.count2)*4, err, err_info)) return -1; header_size += (capsarec_hdr.count1 + capsarec_hdr.count2)*4; break; case 2: if (!wtap_read_bytes_or_eof(fh, &pbrec_hdr, sizeof pbrec_hdr, err, err_info)) return -1; rec_size = GUINT16_FROM_LE(pbrec_hdr.rec_len); orig_size = GUINT16_FROM_LE(pbrec_hdr.orig_len); packet_size = GUINT16_FROM_LE(pbrec_hdr.incl_len); header_size = sizeof pbrec_hdr; timestamp = (((uint64_t)GUINT32_FROM_LE(pbrec_hdr.timestamphi))<<32) + GUINT32_FROM_LE(pbrec_hdr.timestamplo); /* * XXX - from the results of some conversions between * Capsa format and pcap by Colasoft Packet Builder, * I do not trust its conversion of time stamps (at * least one of Colasoft's sample files, when * converted to pcap format, has, as its time stamps, * time stamps on the day after the conversion was * done, which seems like more than just coincidence). */ break; default: ws_assert_not_reached(); *err = WTAP_ERR_INTERNAL; *err_info = ws_strdup_printf("capsa: format indicator is %u", capsa->format_indicator); return -1; } if (orig_size > WTAP_MAX_PACKET_SIZE_STANDARD) { /* * Probably a corrupt capture file; don't blow up trying * to allocate space for an immensely-large packet. */ *err = WTAP_ERR_BAD_FILE; *err_info = ws_strdup_printf("capsa: File has %u-byte original length, bigger than maximum of %u", orig_size, WTAP_MAX_PACKET_SIZE_STANDARD); return -1; } if (packet_size > WTAP_MAX_PACKET_SIZE_STANDARD) { /* * Probably a corrupt capture file; don't blow up trying * to allocate space for an immensely-large packet. */ *err = WTAP_ERR_BAD_FILE; *err_info = ws_strdup_printf("capsa: File has %u-byte packet, bigger than maximum of %u", packet_size, WTAP_MAX_PACKET_SIZE_STANDARD); return -1; } if (header_size + packet_size > rec_size) { /* * Probably a corrupt capture file. */ *err = WTAP_ERR_BAD_FILE; *err_info = ws_strdup_printf("capsa: File has %u-byte packet with %u-byte record header, bigger than record size %u", packet_size, header_size, rec_size); return -1; } /* * The "on the wire" record size always includes the CRC. * If it's greater than the "captured" size by 4, then * we subtract 4 from it, to reflect the way the "on the wire" * record size works for other file formats. */ if (orig_size == packet_size + 4) orig_size = packet_size; /* * We assume there's no FCS in this frame. * XXX - is there ever one? */ rec->rec_header.packet_header.pseudo_header.eth.fcs_len = 0; rec->rec_type = REC_TYPE_PACKET; rec->block = wtap_block_create(WTAP_BLOCK_PACKET); rec->rec_header.packet_header.caplen = packet_size; rec->rec_header.packet_header.len = orig_size; rec->presence_flags = WTAP_HAS_CAP_LEN|WTAP_HAS_TS; rec->ts.secs = (time_t)(timestamp / 1000000); rec->ts.nsecs = ((int)(timestamp % 1000000))*1000; /* * Read the packet data. */ if (!wtap_read_packet_bytes(fh, buf, packet_size, err, err_info)) return -1; /* failed */ return rec_size - (header_size + packet_size); } static const struct supported_block_type capsa_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 capsa_info = { "Colasoft Capsa format", "capsa", "cscpkt", NULL, false, BLOCKS_SUPPORTED(capsa_blocks_supported), NULL, NULL, NULL }; static const struct supported_block_type packet_builder_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 packet_builder_info = { "Colasoft Packet Builder format", "colasoft-pb", "cscpkt", NULL, false, BLOCKS_SUPPORTED(packet_builder_blocks_supported), NULL, NULL, NULL }; void register_capsa(void) { capsa_file_type_subtype = wtap_register_file_type_subtype(&capsa_info); packet_builder_file_type_subtype = wtap_register_file_type_subtype(&packet_builder_info); /* * Register names for backwards compatibility with the * wtap_filetypes table in Lua. */ wtap_register_backwards_compatibility_lua_name("COLASOFT_CAPSA", capsa_file_type_subtype); wtap_register_backwards_compatibility_lua_name("COLASOFT_PACKET_BUILDER", packet_builder_file_type_subtype); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 8 * tab-width: 8 * indent-tabs-mode: t * End: * * vi: set shiftwidth=8 tabstop=8 noexpandtab: * :indentSize=8:tabSize=8:noTabs=false: */