212 lines
6.7 KiB
C
212 lines
6.7 KiB
C
/* packet-enc.c
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*
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* Copyright (c) 2003 Markus Friedl. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/capture_dissectors.h>
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#include <epan/aftypes.h>
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#include <wsutil/pint.h>
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void proto_register_enc(void);
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void proto_reg_handoff_enc(void);
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/* The header in OpenBSD Encapsulating Interface files. */
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struct enchdr {
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guint32 af;
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guint32 spi;
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guint32 flags;
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};
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#define BSD_ENC_HDRLEN 12
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#define BSD_ENC_M_CONF 0x00000400 /* payload encrypted */
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#define BSD_ENC_M_AUTH 0x00000800 /* payload authenticated */
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#define BSD_ENC_M_COMP 0x00001000 /* payload compressed */
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#define BSD_ENC_M_AUTH_AH 0x00002000 /* header authenticated */
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#define BSD_ENC_M_RESERVED 0xFFFFC3FF /* Reserved/unused flags */
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static dissector_table_t enc_dissector_table;
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/* header fields */
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static int proto_enc = -1;
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static int hf_enc_af = -1;
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static int hf_enc_spi = -1;
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static int hf_enc_flags = -1;
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static int hf_enc_flags_payload_enc = -1;
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static int hf_enc_flags_payload_auth = -1;
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static int hf_enc_flags_payload_compress = -1;
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static int hf_enc_flags_header_auth = -1;
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static int hf_enc_flags_reserved = -1;
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static gint ett_enc = -1;
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static gint ett_enc_flag = -1;
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static gboolean
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capture_enc(const guchar *pd, int offset _U_, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
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{
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guint32 af;
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if (!BYTES_ARE_IN_FRAME(0, len, BSD_ENC_HDRLEN))
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return FALSE;
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memcpy((char *)&af, (const char *)&pd[0], sizeof(af));
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if ((af & 0xFFFF0000) != 0) {
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/*
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* BSD AF_ types will always have the upper 16 bits as 0, so if any
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* of them are non-zero, the af field must be byte-swapped, and
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* will, at least in DLT_ENC headers, always have at least one of
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* the lower 16 bits not being 0 (it won't be AF_UNSPEC, which is
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* 0), so if the af field is byte-swapped, at least one of the
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* upper 16 bits will be 0.
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*/
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af = GUINT32_SWAP_LE_BE(af);
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}
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return try_capture_dissector("enc", af, pd, BSD_ENC_HDRLEN, len, cpinfo, pseudo_header);
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}
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static const value_string af_vals[] = {
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{ BSD_AF_INET, "IPv4" },
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{ BSD_AF_INET6_BSD, "IPv6" },
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{ 0, NULL }
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};
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static int
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dissect_enc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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struct enchdr ench;
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guint writer_encoding;
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tvbuff_t *next_tvb;
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proto_tree *enc_tree;
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proto_item *ti;
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static int * const flags[] = {
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&hf_enc_flags_payload_enc,
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&hf_enc_flags_payload_auth,
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&hf_enc_flags_payload_compress,
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&hf_enc_flags_header_auth,
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&hf_enc_flags_reserved,
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NULL
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};
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "ENC");
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/*
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* Initially assume the file was written by a host with our byte order.
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*/
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writer_encoding = ENC_HOST_ENDIAN;
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ench.af = tvb_get_h_guint32(tvb, 0);
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if ((ench.af & 0xFFFF0000) != 0) {
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/*
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* BSD AF_ types will always have the upper 16 bits as 0, so if any
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* of them are non-zero, the af field must be byte-swapped, and
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* will, at least in DLT_ENC headers, always have at least one of
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* the lower 16 bits not being 0 (it won't be AF_UNSPEC, which is
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* 0), so if the af field is byte-swapped, at least one of the
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* upper 16 bits will be 0.
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*/
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ench.af = GUINT32_SWAP_LE_BE(ench.af);
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/*
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* It was written by a host with the *opposite* byte order.
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*/
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writer_encoding = ENC_ANTI_HOST_ENDIAN;
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}
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ench.spi = tvb_get_ntohl(tvb, 4);
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_enc, tvb, 0,
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BSD_ENC_HDRLEN,
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"Enc %s, SPI 0x%8.8x",
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val_to_str(ench.af, af_vals, "unknown (%u)"),
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ench.spi);
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enc_tree = proto_item_add_subtree(ti, ett_enc);
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proto_tree_add_item(enc_tree, hf_enc_af, tvb, 0, 4, writer_encoding);
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proto_tree_add_item(enc_tree, hf_enc_spi, tvb, 4, 4, ENC_BIG_ENDIAN);
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proto_tree_add_bitmask(enc_tree, tvb, 8, hf_enc_flags, ett_enc_flag, flags, writer_encoding);
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}
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/* Set the tvbuff for the payload after the header */
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next_tvb = tvb_new_subset_remaining(tvb, BSD_ENC_HDRLEN);
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if (!dissector_try_uint(enc_dissector_table, ench.af, next_tvb, pinfo, tree))
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call_data_dissector(next_tvb, pinfo, tree);
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return tvb_captured_length(tvb);
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}
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void
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proto_register_enc(void)
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{
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static hf_register_info hf[] = {
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{ &hf_enc_af,
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{ "Address Family", "enc.af", FT_UINT32, BASE_DEC, VALS(af_vals), 0x0,
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"Protocol (IPv4 vs IPv6)", HFILL }},
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{ &hf_enc_spi,
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{ "SPI", "enc.spi", FT_UINT32, BASE_HEX, NULL, 0x0,
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"Security Parameter Index", HFILL }},
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{ &hf_enc_flags,
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{ "Flags", "enc.flags", FT_UINT32, BASE_HEX, NULL, 0x0,
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"ENC flags", HFILL }},
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{ &hf_enc_flags_payload_enc,
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{ "Payload encrypted", "enc.flags.payload_enc", FT_BOOLEAN, 32, NULL, BSD_ENC_M_CONF,
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NULL, HFILL }},
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{ &hf_enc_flags_payload_auth,
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{ "Payload authenticated", "enc.flags.payload_auth", FT_BOOLEAN, 32, NULL, BSD_ENC_M_AUTH,
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NULL, HFILL }},
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{ &hf_enc_flags_payload_compress,
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{ "Payload compressed", "enc.flags.payload_compress", FT_BOOLEAN, 32, NULL, BSD_ENC_M_COMP,
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NULL, HFILL }},
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{ &hf_enc_flags_header_auth,
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{ "Header authenticated", "enc.flags.header_auth", FT_BOOLEAN, 32, NULL, BSD_ENC_M_AUTH_AH,
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NULL, HFILL }},
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{ &hf_enc_flags_reserved,
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{ "Reserved", "enc.flags.reserved", FT_UINT32, BASE_HEX, NULL, BSD_ENC_M_RESERVED,
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NULL, HFILL }},
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};
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static gint *ett[] =
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{
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&ett_enc,
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&ett_enc_flag
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};
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proto_enc = proto_register_protocol("OpenBSD Encapsulating device",
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"ENC", "enc");
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proto_register_field_array(proto_enc, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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enc_dissector_table = register_dissector_table("enc", "OpenBSD Encapsulating device", proto_enc, FT_UINT32, BASE_DEC);
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register_capture_dissector_table("enc", "ENC");
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}
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void
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proto_reg_handoff_enc(void)
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{
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dissector_handle_t enc_handle;
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capture_dissector_handle_t enc_cap_handle;
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enc_handle = create_dissector_handle(dissect_enc, proto_enc);
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dissector_add_uint("wtap_encap", WTAP_ENCAP_ENC, enc_handle);
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enc_cap_handle = create_capture_dissector_handle(capture_enc, proto_enc);
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capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_ENC, enc_cap_handle);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=2 tabstop=8 expandtab:
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* :indentSize=2:tabSize=8:noTabs=true:
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*/
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