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/* packet-fpp.c
 * Routines for IEEE 802.3br Frame Preemption Protocol packet disassembly
 *
 * Copyright 2017, Anton Glukhov <anton.a.glukhov@gmail.com>
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include "config.h"

#include <epan/packet.h>
#include <wiretap/wtap.h>

#include <epan/expert.h>
#include <epan/conversation.h>
#include <wsutil/crc32.h>
#include <epan/crc32-tvb.h>
#include <epan/reassemble.h>
#include <epan/proto_data.h>

void proto_register_fpp(void);
void proto_reg_handoff_fpp(void);

static int proto_fpp = -1;

static dissector_handle_t fpp_handle;

static int hf_fpp_preamble = -1;
static int hf_fpp_preamble_seventh = -1;
static int hf_fpp_preamble_eight = -1;
static int hf_fpp_mdata = -1;
static int hf_fpp_crc32 = -1;
static int hf_fpp_crc32_status = -1;
static int hf_fpp_mcrc32 = -1;
static int hf_fpp_mcrc32_status = -1;

static expert_field ei_fpp_crc32 = EI_INIT;
static expert_field ei_fpp_mcrc32 = EI_INIT;

static gint ett_fpp = -1;
static gint ett_fpp_preamble = -1;

static reassembly_table fpp_reassembly_table;

static dissector_handle_t ethl2_handle;

/* Reassembly Data */
static int hf_fpp_fragments = -1;
static int hf_fpp_fragment = -1;
static int hf_fpp_fragment_overlap = -1;
static int hf_fpp_fragment_overlap_conflicts = -1;
static int hf_fpp_fragment_multiple_tails = -1;
static int hf_fpp_fragment_too_long_fragment = -1;
static int hf_fpp_fragment_error = -1;
static int hf_fpp_fragment_count = -1;
static int hf_fpp_reassembled_in = -1;
static int hf_fpp_reassembled_length = -1;
static gint ett_fpp_fragment = -1;
static gint ett_fpp_fragments = -1;

static const fragment_items fpp_frag_items = {
	/* Fragment subtrees */
	&ett_fpp_fragment,
	&ett_fpp_fragments,
	/* Fragment fields */
	&hf_fpp_fragments,
	&hf_fpp_fragment,
	&hf_fpp_fragment_overlap,
	&hf_fpp_fragment_overlap_conflicts,
	&hf_fpp_fragment_multiple_tails,
	&hf_fpp_fragment_too_long_fragment,
	&hf_fpp_fragment_error,
	&hf_fpp_fragment_count,
	/* Reassembled in field */
	&hf_fpp_reassembled_in,
	/* Reassembled length field */
	&hf_fpp_reassembled_length,
	/* Reassembled data field */
	NULL,
	/* Tag */
	"fpp fragments"
};

#define FPP_PREAMBLE_LENGTH		8
#define FPP_CRC_LENGTH			4

#define FPP_CONVERSATION_ID		0

typedef enum {
	FPP_Packet_Expess,
	FPP_Packet_Verify,
	FPP_Packet_Response,
	FPP_Packet_Init,
	FPP_Packet_Cont,
	FPP_Packet_Invalid,
} fpp_packet_t;

typedef enum {
	SMD_Verify			= 0x7,
	SMD_Respond			= 0x19,
	SMD_Express			= 0xd5,
	SMD_PP_Start_0		= 0xe6,
	SMD_PP_Start_1		= 0x4c,
	SMD_PP_Start_2		= 0x7f,
	SMD_PP_Start_3		= 0xb3,
	FragCount_0			= SMD_PP_Start_0,
	FragCount_1			= SMD_PP_Start_1,
	FragCount_2			= SMD_PP_Start_2,
	FragCount_3			= SMD_PP_Start_3
} first_delim;

typedef enum {
	Octet_0x55			= 0x55,
	SMD_PP_ContFrag_0	= 0x61,
	SMD_PP_ContFrag_1	= 0x52,
	SMD_PP_ContFrag_2	= 0x9e,
	SMD_PP_ContFrag_3	= 0x2a,
} second_delim;

typedef enum {
	CRC_CRC,
	CRC_mCRC,
	CRC_FALSE
} fpp_crc_t;

/* Packets with correct CRC sum */
static const value_string preemptive_delim_desc[] = {
	{ SMD_PP_Start_0, "[Non-fragmented packet: SMD-S0]" },
	{ SMD_PP_Start_1, "[Non-fragmented packet: SMD-S1]" },
	{ SMD_PP_Start_2, "[Non-fragmented packet: SMD-S2]" },
	{ SMD_PP_Start_3, "[Non-fragmented packet: SMD-S3]" },
	{ 0x0, NULL }
};

/* Packets with correct mCRC sum */
static const value_string initial_delim_desc[] = {
	{ SMD_PP_Start_0, "[Initial fragment: SMD-S0]" },
	{ SMD_PP_Start_1, "[Initial fragment: SMD-S1]" },
	{ SMD_PP_Start_2, "[Initial fragment: SMD-S2]" },
	{ SMD_PP_Start_3, "[Initial fragment: SMD-S3]" },
	{ 0x0, NULL }
};

static const value_string continuation_delim_desc[] = {
	{ SMD_PP_ContFrag_0, "[Continuation fragment: SMD-C0]" },
	{ SMD_PP_ContFrag_1, "[Continuation fragment: SMD-C1]" },
	{ SMD_PP_ContFrag_2, "[Continuation fragment: SMD-C2]" },
	{ SMD_PP_ContFrag_3, "[Continuation fragment: SMD-C3]" },
	{ 0x0, NULL }
};

static const value_string frag_count_delim_desc[] = {
	{ FragCount_0, "[#0]"},
	{ FragCount_1, "[#1]"},
	{ FragCount_2, "[#2]"},
	{ FragCount_3, "[#3]"},
	{ 0x0, NULL }
};

static fpp_crc_t
get_crc_stat(tvbuff_t *tvb, guint32 crc, guint32 mcrc) {
	fpp_crc_t crc_val;
	if (tvb_get_guint32(tvb, tvb_reported_length(tvb) - FPP_CRC_LENGTH, ENC_BIG_ENDIAN) == crc) {
		crc_val = CRC_CRC;
	} else if (tvb_get_guint32(tvb, tvb_reported_length(tvb) - FPP_CRC_LENGTH, ENC_BIG_ENDIAN) == mcrc) {
		crc_val = CRC_mCRC;
	} else {
		crc_val = CRC_FALSE;
	}
	return crc_val;
}

static void
col_fstr_process(tvbuff_t *tvb, packet_info *pinfo, fpp_crc_t crc_val) {
	if (tvb_get_guint8(tvb, 6) == Octet_0x55) {
		if (tvb_get_guint8(tvb, 7) == SMD_Express) {
			col_add_str(pinfo->cinfo, COL_INFO, "[Express]");
		} else {
			if ((crc_val == CRC_CRC) || (crc_val == CRC_FALSE))
				col_add_fstr(pinfo->cinfo, COL_INFO, "%s", try_val_to_str(tvb_get_guint8(tvb, 7), preemptive_delim_desc));
			else
				col_add_fstr(pinfo->cinfo, COL_INFO, "%s", try_val_to_str(tvb_get_guint8(tvb, 7), initial_delim_desc));
		}
	} else {
		col_add_fstr(pinfo->cinfo, COL_INFO, "%s %s", try_val_to_str(tvb_get_guint8(tvb, 6), continuation_delim_desc),
													try_val_to_str(tvb_get_guint8(tvb, 7), frag_count_delim_desc));
	}
}

static fpp_packet_t
get_packet_type(tvbuff_t *tvb) {
	/* function analyze a packet based on preamble and ignore crc */
	guint8 smd1 = tvb_get_guint8(tvb, 6);
	guint8 smd2 = tvb_get_guint8(tvb, 7);

	switch (smd1) {
		case Octet_0x55:
			switch (smd2) {
				case SMD_PP_Start_0:
				case SMD_PP_Start_1:
				case SMD_PP_Start_2:
				case SMD_PP_Start_3:
					return FPP_Packet_Init;
				case SMD_Verify:
					return FPP_Packet_Verify;
				case SMD_Respond:
					return FPP_Packet_Response;
				case SMD_Express:
					return FPP_Packet_Expess;
				default:
					return FPP_Packet_Invalid;
			}
		case SMD_PP_ContFrag_0:
		case SMD_PP_ContFrag_1:
		case SMD_PP_ContFrag_2:
		case SMD_PP_ContFrag_3:
			switch (smd2) {
				case FragCount_0:
				case FragCount_1:
				case FragCount_2:
				case FragCount_3:
					return FPP_Packet_Cont;
				default:
					return FPP_Packet_Invalid;
			}
		default:
			return FPP_Packet_Invalid;
	}

	return FPP_Packet_Invalid;
}

struct _fpp_ctx_t {
	gboolean preemption;
	guint8 frame_cnt;
	guint8 frag_cnt;
	guint32 size;
};

typedef struct _fpp_ctx_t fpp_ctx_t;

static void
init_fpp_ctx(struct _fpp_ctx_t *ctx, guint8 frame_cnt) {
	ctx->preemption = TRUE;
	ctx->frame_cnt = frame_cnt;
	ctx->frag_cnt = FragCount_3;
	ctx->size = 0;
}

static guint8
frag_cnt_next(guint8 cur_num) {
	if (cur_num == FragCount_0)
		return FragCount_1;
	else if (cur_num == FragCount_1)
		return FragCount_2;
	else if (cur_num == FragCount_2)
		return FragCount_3;
	else if (cur_num == FragCount_3)
		return FragCount_0;
	else
		return FragCount_0;
}

static guint8
get_cont_by_start(guint8 start_cnt) {
	if (start_cnt == SMD_PP_Start_0)
		return SMD_PP_ContFrag_0;
	else if (start_cnt == SMD_PP_Start_1)
		return SMD_PP_ContFrag_1;
	else if (start_cnt == SMD_PP_Start_2)
		return SMD_PP_ContFrag_2;
	else if (start_cnt == SMD_PP_Start_3)
		return SMD_PP_ContFrag_3;
	else
		return SMD_PP_ContFrag_0;
}

struct _fpp_pdata_t {
	/* struct for future possible usage */
	guint32 offset;
};

typedef struct _fpp_pdata_t fpp_pdata_t;

static void
drop_conversation(conversation_t *conv) {
	fpp_ctx_t *ctx;
	ctx = (fpp_ctx_t*)conversation_get_proto_data(conv, proto_fpp);
	if (ctx != NULL) {
		wmem_free(wmem_file_scope(), ctx);
	}
	conversation_delete_proto_data(conv, proto_fpp);
}

static void
drop_fragments(packet_info *pinfo) {
	tvbuff_t *tvbuf;
	tvbuf = fragment_delete(&fpp_reassembly_table, pinfo, 1, NULL);
	if (tvbuf != NULL) {
		tvb_free(tvbuf);
	}
}

static tvbuff_t *
dissect_preemption(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 crc, fpp_crc_t crc_val) {

	fpp_packet_t pck_type;

	guint8 smd1 = tvb_get_guint8(tvb, 6);
	guint8 smd2 = tvb_get_guint8(tvb, 7);

	guint crc_offset = tvb_reported_length(tvb) - FPP_CRC_LENGTH;
	gint frag_size = tvb_reported_length(tvb) - FPP_PREAMBLE_LENGTH - FPP_CRC_LENGTH;
	/* Reassembly parameters. */
	tvbuff_t *new_tvb = NULL;
	fragment_head *frag_data;
	gboolean save_fragmented;
	conversation_t *conv;
	fpp_ctx_t *ctx;

	conv = find_conversation_by_id(pinfo->num, ENDPOINT_NONE, FPP_CONVERSATION_ID, 0);
	if (!conv) {
		conv = conversation_new_by_id(pinfo->num, ENDPOINT_NONE, FPP_CONVERSATION_ID, 0);
	}

	/* Create a tree for the preamble. */
	proto_item *ti_preamble = proto_tree_add_item(tree, hf_fpp_preamble, tvb, 0, FPP_PREAMBLE_LENGTH, ENC_BIG_ENDIAN);

	proto_tree_add_item(tree, hf_fpp_mdata, tvb, FPP_PREAMBLE_LENGTH, frag_size, ENC_NA);

	proto_tree *fpp_preamble_tree = proto_item_add_subtree(ti_preamble, ett_fpp_preamble);
	proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_seventh, tvb, 6, 1, ENC_BIG_ENDIAN);
	proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_eight, tvb, 7, 1, ENC_BIG_ENDIAN);

	pck_type = get_packet_type(tvb);
	if (pck_type == FPP_Packet_Init) {
		if (crc_val == CRC_CRC) {
			/* Non-fragmented packet */
			drop_fragments(pinfo);

			if (!PINFO_FD_VISITED(pinfo)) {
				drop_conversation(conv);
			}

			proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_crc32, hf_fpp_crc32_status, &ei_fpp_crc32, pinfo, crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);

			return tvb_new_subset_length(tvb, FPP_PREAMBLE_LENGTH, frag_size);
		} else if (crc_val == CRC_mCRC) {
			/* Init frag */
			drop_fragments(pinfo);

			if (!PINFO_FD_VISITED(pinfo)) {
				// Fist delete previous conversation
				drop_conversation(conv);
				ctx = (struct _fpp_ctx_t *)wmem_alloc(wmem_file_scope(), sizeof(struct _fpp_ctx_t));
				init_fpp_ctx(ctx, get_cont_by_start(smd2));
				ctx->size = frag_size;
				conversation_add_proto_data(conv, proto_fpp, ctx);
			}

			fragment_add_check(&fpp_reassembly_table,
								tvb, FPP_PREAMBLE_LENGTH, pinfo, 1, NULL,
								0, frag_size, TRUE);

			set_address_tvb(&pinfo->dl_dst, AT_ETHER, 6, tvb, 8);
			set_address_tvb(&pinfo->dst, AT_ETHER, 6, tvb, 8);
			set_address_tvb(&pinfo->dl_src, AT_ETHER, 6, tvb, 14);
			set_address_tvb(&pinfo->src, AT_ETHER, 6, tvb, 14);

			proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
		} else {
			/* Invalid packet */
			drop_fragments(pinfo);

			if (!PINFO_FD_VISITED(pinfo)) {
				drop_conversation(conv);
			}

			proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
		}
	} else if (pck_type == FPP_Packet_Cont) {
		if (crc_val == CRC_mCRC) {
			/* Continuation frag */

			if (!PINFO_FD_VISITED(pinfo)) {
				ctx = (fpp_ctx_t*)conversation_get_proto_data(conv, proto_fpp);
				if ((ctx) && (ctx->preemption) && (ctx->frame_cnt == smd1) && (frag_cnt_next(ctx->frag_cnt) == smd2)) {
					fpp_pdata_t *fpp_pdata = wmem_new(wmem_file_scope(), fpp_pdata_t);
					fpp_pdata->offset = ctx->size;
					p_add_proto_data(wmem_file_scope(), pinfo, proto_fpp, 0, fpp_pdata);

					ctx->size += frag_size;
					ctx->frag_cnt = smd2;
				} else {
					// There is no conversation or ctx is wrong
					drop_conversation(conv);
				}
			}

			fpp_pdata_t *fpp_pdata = (fpp_pdata_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_fpp, 0);
			if (fpp_pdata) {
				fragment_add_check(&fpp_reassembly_table,
									tvb, FPP_PREAMBLE_LENGTH, pinfo, 1, NULL,
									fpp_pdata->offset, frag_size, TRUE);
			} else {
				drop_fragments(pinfo);
			}

			proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
		} else {
			/* Suppose that the last fragment dissected
				1. preemption is active
				2. check frame count and frag count values
				After these steps check crc of entire reassembled frame
			*/
			if (!PINFO_FD_VISITED(pinfo)) {
				ctx = (fpp_ctx_t*)conversation_get_proto_data(conv, proto_fpp);
				if ((ctx) && (ctx->preemption) && (ctx->frame_cnt == smd1) && (frag_cnt_next(ctx->frag_cnt) == smd2)) {
					fpp_pdata_t *fpp_pdata = wmem_new(wmem_file_scope(), fpp_pdata_t);
					fpp_pdata->offset = ctx->size;
					p_add_proto_data(wmem_file_scope(), pinfo, proto_fpp, 0, fpp_pdata);
				}

				drop_conversation(conv);
			}

			fpp_pdata_t *fpp_pdata = (fpp_pdata_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_fpp, 0);
			if (fpp_pdata) {
				save_fragmented = pinfo->fragmented;
				pinfo->fragmented = TRUE;
				frag_data = fragment_add_check(&fpp_reassembly_table,
												tvb, FPP_PREAMBLE_LENGTH, pinfo, 1, NULL,
												fpp_pdata->offset, frag_size, FALSE);
				// Attempt reassembly.
				new_tvb = process_reassembled_data(tvb, FPP_PREAMBLE_LENGTH, pinfo,
													"Reassembled FPP", frag_data, &fpp_frag_items,
													NULL, tree);
				pinfo->fragmented = save_fragmented;
			} else {
				drop_fragments(pinfo);
				proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
			}

			if (new_tvb) {
				/* Reassembly was successful; return the completed datagram. */
				guint32 reassembled_crc = crc32_ccitt_tvb_offset(new_tvb, 0, tvb_reported_length(new_tvb));

				/* Reassembly frame takes place regardless of whether the check sum was correct or not. */
				proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_crc32, -1, &ei_fpp_crc32, pinfo, reassembled_crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);

				return new_tvb;
			} else {
				/* Reassembly was unsuccessful; show this fragment.  This may
					just mean that we don't yet have all the fragments, so
					we should not just continue dissecting. */
				return NULL;
			}
		}
	} else if (pck_type == FPP_Packet_Verify) {
		proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, -1, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
	} else if (pck_type == FPP_Packet_Response) {
		proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_mcrc32, hf_fpp_mcrc32_status, &ei_fpp_mcrc32, pinfo, (crc ^ 0xffff0000), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);
	}

	return NULL;
}

static tvbuff_t *
dissect_express(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, guint32 crc, fpp_crc_t crc_val) {

	guint crc_offset = tvb_reported_length(tvb) - FPP_CRC_LENGTH;
	guint offset = 0;
	guint pdu_data_len = tvb_reported_length(tvb) - FPP_PREAMBLE_LENGTH - FPP_CRC_LENGTH;

	proto_item *ti_preamble = proto_tree_add_item(tree, hf_fpp_preamble, tvb, offset, 8, ENC_BIG_ENDIAN);
	offset += FPP_PREAMBLE_LENGTH;

	proto_tree_add_item(tree, hf_fpp_mdata, tvb, offset, pdu_data_len, ENC_NA);

	proto_tree *fpp_preamble_tree = proto_item_add_subtree(ti_preamble, ett_fpp_preamble);
	proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_seventh, tvb, 6, 1, ENC_BIG_ENDIAN);
	proto_tree_add_item(fpp_preamble_tree, hf_fpp_preamble_eight, tvb, 7, 1, ENC_BIG_ENDIAN);

	proto_tree_add_checksum(tree, tvb, crc_offset, hf_fpp_crc32, hf_fpp_crc32_status, &ei_fpp_crc32, pinfo, crc, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY);

	if (crc_val == CRC_CRC) {
		return tvb_new_subset_length(tvb, FPP_PREAMBLE_LENGTH, pdu_data_len);
	}
	return NULL;
}

static int
dissect_fpp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
	guint32 crc, mcrc;
	fpp_crc_t crc_val;
	tvbuff_t *next = tvb;
	guint pdu_data_len = tvb_reported_length(tvb) - FPP_PREAMBLE_LENGTH - FPP_CRC_LENGTH;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, "FPP");
	col_clear(pinfo->cinfo,COL_INFO);

	crc = crc32_ccitt_tvb_offset(tvb, FPP_PREAMBLE_LENGTH, pdu_data_len);
	mcrc = crc ^ 0xffff0000;

	// get crc type
	crc_val = get_crc_stat(tvb, crc, mcrc);

	// fill column Info
	col_fstr_process(tvb, pinfo, crc_val);

	proto_item *ti = proto_tree_add_item(tree, proto_fpp, tvb, 0, -1, ENC_NA);

	proto_tree *fpp_tree = proto_item_add_subtree(ti, ett_fpp);

	switch (get_packet_type(tvb)) {
		case FPP_Packet_Expess:
			next = dissect_express(tvb, pinfo, fpp_tree, crc, crc_val);
			break;
		case FPP_Packet_Init:
		case FPP_Packet_Cont:
		case FPP_Packet_Verify:
		case FPP_Packet_Response:
			next = dissect_preemption(tvb, pinfo, fpp_tree, crc, crc_val);
			break;
		default:
			break;
	}

	if (next) {
		call_dissector(ethl2_handle, next, pinfo, tree);
	} else {
		tvbuff_t *new_tvb = tvb_new_subset_length(tvb, FPP_PREAMBLE_LENGTH, pdu_data_len);
		call_data_dissector(new_tvb, pinfo, tree);
	}
	return tvb_captured_length(tvb);
}

void
proto_register_fpp(void)
{
	static hf_register_info hf[] = {
		{ &hf_fpp_preamble,
			{ "Preamble", "fpp.preamble",
				FT_UINT64, BASE_HEX,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_preamble_seventh,
			{ "Seventh", "fpp.preamble.seventh",
				FT_UINT8, BASE_HEX,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_preamble_eight,
			{ "Eight", "fpp.preamble.eight",
				FT_UINT8, BASE_HEX,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_mdata,
			{ "mData", "fpp.mdata",
				FT_BYTES, BASE_NONE,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_crc32,
			{ "CRC", "fpp.crc32",
				FT_UINT32, BASE_HEX,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_crc32_status,
			{ "Checksum Status", "fpp.checksum.status",
				FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
				NULL, HFILL
			},
		},
		{ &hf_fpp_mcrc32,
			{ "mCRC", "fpp.mcrc32",
				FT_UINT32, BASE_HEX,
				NULL, 0x0,
				NULL, HFILL }
		},
		{ &hf_fpp_mcrc32_status,
			{ "Checksum Status", "fpp.checksum.status",
				FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
				NULL, HFILL
			},
		},

		/* Reassembly fields. */
		{ &hf_fpp_fragments,
			{ "Message fragments", "fpp.fragments",
				FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment,
			{ "Message fragment", "fpp.fragment",
				FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_overlap,
			{ "Message fragment overlap", "fpp.fragment.overlap",
				FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_overlap_conflicts,
			{ "Message fragment overlapping with conflicting data", "fpp.fragment.overlap.conflicts",
				FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_multiple_tails,
			{ "Message has multiple tail fragments", "fpp.fragment.multiple_tails",
				FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_too_long_fragment,
			{ "Message fragment too long", "fpp.fragment.too_long_fragment",
				FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_error,
			{ "Message defragmentation error", "fpp.fragment.error",
				FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_fragment_count,
			{ "Message fragment count", "fpp.fragment.count",
				FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_reassembled_in,
			{ "Reassembled in", "fpp.reassembled.in",
				FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL }},
		{ &hf_fpp_reassembled_length,
			{ "Reassembled fpp length", "fpp.reassembled.length",
				FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL }},
	};

	/* Setup protocol subtree array */
	static gint *ett[] = {
		&ett_fpp,
		&ett_fpp_preamble,
		/* Reassembly subtrees. */
		&ett_fpp_fragment,
		&ett_fpp_fragments
	};

	static ei_register_info ei[] = {
		{ &ei_fpp_mcrc32,
			{ "fpp.mcrc32_bad", PI_CHECKSUM, PI_ERROR,
				"Bad mCRC checksum", EXPFILL }
		},
		{ &ei_fpp_crc32,
			{ "fpp.crc32_bad", PI_CHECKSUM, PI_ERROR,
				"Bad CRC checksum", EXPFILL }
		},
	};

	expert_module_t* expert_fpp;

	proto_fpp = proto_register_protocol (
		"IEEE 802.3br Frame Preemption Protocol",
		"Frame Preemption Protocol",
		"fpp"
	);

	proto_register_field_array(proto_fpp, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));
	expert_fpp = expert_register_protocol(proto_fpp);
	expert_register_field_array(expert_fpp, ei, array_length(ei));

	reassembly_table_register(&fpp_reassembly_table, &addresses_reassembly_table_functions);

	fpp_handle = register_dissector("fpp", dissect_fpp, proto_fpp);
}

void
proto_reg_handoff_fpp(void)
{
	dissector_add_uint("wtap_encap", WTAP_ENCAP_ETHERNET_MPACKET, fpp_handle);

	ethl2_handle = find_dissector_add_dependency("eth_withoutfcs", proto_fpp);
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 noexpandtab:
 * :indentSize=4:tabSize=8:noTabs=false:
 */