/* packet-nano.c

 * Routines for Nano / RaiBlocks dissection

 * Copyright 2018, Roland Haenel <roland@haenel.me>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

/*

 * For information about Nano / RaiBlocks, go to http://www.nano.org

 */

#include <config.h>

#include <conversation.h>

#include "packet-tcp.h"

#include <proto_data.h>

#include <epan/packet.h>

#include <epan/to_str.h>

#include <wsutil/str_util.h>

void proto_reg_handoff_nano(void);

void proto_register_nano(void);

static dissector_handle_t nano_handle, nano_tcp_handle;

static int proto_nano;

static int hf_nano_magic_number;

static int hf_nano_version_max;

static int hf_nano_version_using;

static int hf_nano_version_min;

static int hf_nano_packet_type;

static int hf_nano_extensions;

static int hf_nano_extensions_block_type;

static int hf_nano_keepalive_peer_ip;

static int hf_nano_keepalive_peer_port;

static int hf_nano_block_hash_previous;

static int hf_nano_block_hash_source;

static int hf_nano_block_signature;

static int hf_nano_block_work;

static int hf_nano_block_destination_account;

static int hf_nano_block_balance;

static int hf_nano_block_account;

static int hf_nano_block_representative_account;

static int hf_nano_block_link;

static int hf_nano_vote_account;

static int hf_nano_vote_signature;

static int hf_nano_vote_sequence;

static int hf_nano_bulk_pull_account;

static int hf_nano_bulk_pull_block_hash_end;

static int hf_nano_frontier_req_account;

static int hf_nano_frontier_req_age;

static int hf_nano_frontier_req_count;

static int hf_nano_bulk_pull_blocks_min_hash;

static int hf_nano_bulk_pull_blocks_max_hash;

static int hf_nano_bulk_pull_blocks_mode;

static int hf_nano_bulk_pull_blocks_max_count;

static int hf_nano_bulk_push_block_type;

static int hf_nano_bulk_pull_block_type;

static int hf_nano_frontier_account;

static int hf_nano_frontier_head_hash;

static int ett_nano;

static int ett_nano_header;

static int ett_nano_extensions;

static int ett_nano_peers;

static int ett_nano_peer_details[8];

static int ett_nano_block;

static int ett_nano_vote;

static int ett_nano_bulk_pull;

static int ett_nano_frontier_req;

static int ett_nano_bulk_pull_blocks;

static int ett_nano_frontier;

#define NANO_PACKET_TYPE_INVALID 0

#define NANO_PACKET_TYPE_NOT_A_TYPE 1

#define NANO_PACKET_TYPE_KEEPALIVE 2

#define NANO_PACKET_TYPE_PUBLISH 3

#define NANO_PACKET_TYPE_CONFIRM_REQ 4

#define NANO_PACKET_TYPE_CONFIRM_ACK 5

#define NANO_PACKET_TYPE_BULK_PULL 6

#define NANO_PACKET_TYPE_BULK_PUSH 7

#define NANO_PACKET_TYPE_FRONTIER_REQ 8

#define NANO_PACKET_TYPE_BULK_PULL_BLOCKS 9

static const value_string nano_packet_type_strings[] = {

  { NANO_PACKET_TYPE_INVALID, "Invalid" },

  { NANO_PACKET_TYPE_NOT_A_TYPE, "Not A Type" },

  { NANO_PACKET_TYPE_KEEPALIVE, "Keepalive" },

  { NANO_PACKET_TYPE_PUBLISH, "Publish" },

  { NANO_PACKET_TYPE_CONFIRM_REQ, "Confirm Req" },

  { NANO_PACKET_TYPE_CONFIRM_ACK, "Confirm Ack" },

  { NANO_PACKET_TYPE_BULK_PULL, "Bulk Pull" },

  { NANO_PACKET_TYPE_BULK_PUSH, "Bulk Push" },

  { NANO_PACKET_TYPE_FRONTIER_REQ, "Frontier Req" },

  { NANO_PACKET_TYPE_BULK_PULL_BLOCKS, "Bulk Pull Blocks" },

  { 0, NULL },

};

#define NANO_BLOCK_TYPE_INVALID 0

#define NANO_BLOCK_TYPE_NOT_A_BLOCK 1

#define NANO_BLOCK_TYPE_SEND 2

#define NANO_BLOCK_TYPE_RECEIVE 3

#define NANO_BLOCK_TYPE_OPEN 4

#define NANO_BLOCK_TYPE_CHANGE 5

#define NANO_BLOCK_TYPE_STATE 6

static const value_string nano_block_type_strings[] = {

  { NANO_BLOCK_TYPE_INVALID, "Invalid" },

  { NANO_BLOCK_TYPE_NOT_A_BLOCK, "Not A Block" },

  { NANO_BLOCK_TYPE_SEND, "Send" },

  { NANO_BLOCK_TYPE_RECEIVE, "Receive" },

  { NANO_BLOCK_TYPE_OPEN, "Open" },

  { NANO_BLOCK_TYPE_CHANGE, "Change" },

  { NANO_BLOCK_TYPE_STATE, "State" },

  { 0, NULL },

};

static const string_string nano_magic_numbers[] = {

    { "RA", "Nano Test Network" },

    { "RB", "Nano Beta Network" },

    { "RC", "Nano Production Network" },

    { NULL, NULL }

};

#define NANO_BULK_PULL_BLOCKS_MODE_LIST_BLOCKS 0

#define NANO_BULK_PULL_BLOCKS_MODE_CHECKSUM_BLOCKS 1

static const value_string nano_bulk_pull_blocks_mode_strings[] = {

  { NANO_BULK_PULL_BLOCKS_MODE_LIST_BLOCKS, "List Blocks" },

  { NANO_BULK_PULL_BLOCKS_MODE_CHECKSUM_BLOCKS, "Checksum Blocks" },

  { 0, NULL },

};

#define NANO_UDP_PORT 7075 /* Not IANA registered */

#define NANO_TCP_PORT 7075 /* Not IANA registered */

#define NANO_BLOCK_SIZE_SEND    (32+32+16+64+8)

#define NANO_BLOCK_SIZE_RECEIVE (32+32+64+8)

#define NANO_BLOCK_SIZE_OPEN    (32+32+32+64+8)

#define NANO_BLOCK_SIZE_CHANGE  (32+32+64+8)

#define NANO_BLOCK_SIZE_STATE   (32+32+32+16+32+64+8)

// Nano header length, and thus minimum length of any Nano UDP packet (or bootstrap request)

#define NANO_HEADER_LENGTH 8

// Nano bootstrap session state

struct nano_session_state {

    int client_packet_type;

    uint32_t server_port;

};

// dissect the inside of a keepalive packet (that is, the neighbor nodes)

static int dissect_nano_keepalive(tvbuff_t *tvb, packet_info *pinfo, proto_tree *nano_tree, int offset)

{

    proto_item *ti;

    proto_tree *peer_tree, *peer_entry_tree;

    int i, peers;

    ws_in6_addr ip_addr;

    uint32_t port;

    char buf[100];

    peer_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 8*(16+2), ett_nano_peers, NULL, "Peer List");

    peers = 0;

    for (i = 0; i < 8; i++) {

        peer_entry_tree = proto_tree_add_subtree(peer_tree, tvb, offset, 18, ett_nano_peer_details[i], &ti, "Peer");

        tvb_get_ipv6(tvb, offset, &ip_addr);

        proto_tree_add_item(peer_entry_tree, hf_nano_keepalive_peer_ip, tvb, offset, 16, ENC_NA);

        offset += 16;

        proto_tree_add_item_ret_uint(peer_entry_tree, hf_nano_keepalive_peer_port, tvb, offset, 2, ENC_LITTLE_ENDIAN, &port);

        offset += 2;

        if (!memcmp(&ip_addr, "\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0", 16)) {

            proto_item_append_text(ti, ": (none)");

        } else if (!memcmp(&ip_addr, "\x0\x0\x0\x0\x0\x0\x0\x0\x0\x0\xff\xff", 12)) {

            ip_addr_to_str_buf((ws_in4_addr *)((uint8_t *)&ip_addr + 12), buf, sizeof(buf));

            proto_item_append_text(ti, ": %s:%d", buf, port);

            peers++;

        } else {

            ip6_to_str_buf(&ip_addr, buf, sizeof(buf));

            proto_item_append_text(ti, ": [%s]:%d", buf, port);

            peers++;

        }

    }

    col_add_fstr(pinfo->cinfo, COL_INFO, "Keepalive (%d peer%s)", peers, plurality(peers, "", "s"));

    return offset;

}

// dissect a receive block

static int dissect_nano_receive_block(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *block_tree;

    block_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_BLOCK_SIZE_RECEIVE, ett_nano_block, NULL, "Receive Block");

    proto_tree_add_item(block_tree, hf_nano_block_hash_previous, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_hash_source, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(block_tree, hf_nano_block_work, tvb, offset, 8, ENC_NA);

    offset += 8;

    return offset;

}

// dissect a send block

static int dissect_nano_send_block(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *block_tree;

    block_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_BLOCK_SIZE_SEND, ett_nano_block, NULL, "Send Block");

    proto_tree_add_item(block_tree, hf_nano_block_hash_previous, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_destination_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_balance, tvb, offset, 16, ENC_NA);

    offset += 16;

    proto_tree_add_item(block_tree, hf_nano_block_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(block_tree, hf_nano_block_work, tvb, offset, 8, ENC_NA);

    offset += 8;

    return offset;

}

// dissect an open block

static int dissect_nano_open_block(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *block_tree;

    block_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_BLOCK_SIZE_OPEN, ett_nano_block, NULL, "Open Block");

    proto_tree_add_item(block_tree, hf_nano_block_hash_source, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_representative_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(block_tree, hf_nano_block_work, tvb, offset, 8, ENC_NA);

    offset += 8;

    return offset;

}

// dissect an change block

static int dissect_nano_change_block(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *block_tree;

    block_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_BLOCK_SIZE_CHANGE, ett_nano_block, NULL, "Change Block");

    proto_tree_add_item(block_tree, hf_nano_block_hash_previous, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_representative_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(block_tree, hf_nano_block_work, tvb, offset, 8, ENC_NA);

    offset += 8;

    return offset;

}

// dissect a state block

static int dissect_nano_state(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *block_tree;

    block_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_BLOCK_SIZE_STATE, ett_nano_block, NULL, "State Block");

    proto_tree_add_item(block_tree, hf_nano_block_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_hash_previous, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_representative_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_balance, tvb, offset, 16, ENC_NA);

    offset += 16;

    proto_tree_add_item(block_tree, hf_nano_block_link, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(block_tree, hf_nano_block_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(block_tree, hf_nano_block_work, tvb, offset, 8, ENC_NA);

    offset += 8;

    return offset;

}

// dissect a vote

static int dissect_nano_vote(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *vote_tree;

    vote_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 32+64+8, ett_nano_block, NULL, "Vote");

    proto_tree_add_item(vote_tree, hf_nano_vote_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(vote_tree, hf_nano_vote_signature, tvb, offset, 64, ENC_NA);

    offset += 64;

    proto_tree_add_item(vote_tree, hf_nano_vote_sequence, tvb, offset, 8, ENC_LITTLE_ENDIAN);

    offset += 8;

    return offset;

}

// dissect a Nano protocol header, fills in the values

// for nano_packet_type, nano_block_type

static int dissect_nano_header(tvbuff_t *tvb, packet_info *pinfo, proto_tree *nano_tree, int offset, unsigned *nano_packet_type, uint64_t *extensions)

{

    proto_tree *header_tree;

    char *nano_magic_number;

    static int * const nano_extensions[] = {

        &hf_nano_extensions_block_type,

        NULL

    };

    header_tree = proto_tree_add_subtree(nano_tree, tvb, offset, NANO_HEADER_LENGTH, ett_nano_header, NULL, "Nano Protocol Header");

    nano_magic_number = (char*)tvb_get_string_enc(pinfo->pool, tvb, offset, 2, ENC_ASCII);

    proto_tree_add_string_format_value(header_tree, hf_nano_magic_number, tvb, 0,

            2, nano_magic_number, "%s (%s)", str_to_str_wmem(pinfo->pool, nano_magic_number, nano_magic_numbers, "Unknown"), nano_magic_number);

    offset += 2;

    proto_tree_add_item(header_tree, hf_nano_version_max, tvb, offset, 1, ENC_NA);

    offset += 1;

    proto_tree_add_item(header_tree, hf_nano_version_using, tvb, offset, 1, ENC_NA);

    offset += 1;

    proto_tree_add_item(header_tree, hf_nano_version_min, tvb, offset, 1, ENC_NA);

    offset += 1;

    proto_tree_add_item_ret_uint(header_tree, hf_nano_packet_type, tvb, offset, 1, ENC_NA, nano_packet_type);

    offset += 1;

    proto_tree_add_bitmask_ret_uint64(header_tree, tvb, offset, hf_nano_extensions, ett_nano_extensions, nano_extensions, ENC_LITTLE_ENDIAN, extensions);

    offset += 2;

    return offset;

}

// dissect a Nano packet (UDP)

static int dissect_nano(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)

{

    proto_item *ti;

    proto_tree *nano_tree;

    unsigned nano_packet_type, nano_block_type, offset;

    uint64_t extensions;

    /* Check that the packet is long enough for it to belong to us. */

    if (tvb_reported_length(tvb) < NANO_HEADER_LENGTH)

        return 0;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "Nano");

    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_nano, tvb, 0, -1, ENC_NA);

    nano_tree = proto_item_add_subtree(ti, ett_nano);

    offset = dissect_nano_header(tvb, pinfo, nano_tree, 0, &nano_packet_type, &extensions);

    // call specific dissectors for specific packet types

    switch (nano_packet_type) {

        case NANO_PACKET_TYPE_KEEPALIVE:

            return dissect_nano_keepalive(tvb, pinfo, nano_tree, offset);

        case NANO_PACKET_TYPE_PUBLISH:

        case NANO_PACKET_TYPE_CONFIRM_REQ:

        case NANO_PACKET_TYPE_CONFIRM_ACK:

            // set the INFO header with more information

            nano_block_type = (unsigned)((extensions >> 8) & 0xF);

            col_add_fstr(pinfo->cinfo, COL_INFO, "%s (%s)",

                    val_to_str_const(nano_packet_type, VALS(nano_packet_type_strings), " "),

                    val_to_str(pinfo->pool, nano_block_type, VALS(nano_block_type_strings), "Unknown (%d)"));

            // if it's a Confirm Ack packet, we first have a vote

            if (nano_packet_type == NANO_PACKET_TYPE_CONFIRM_ACK) {

                offset = dissect_nano_vote(tvb, nano_tree, offset);

            }

            // dissect the actual block

            switch (nano_block_type) {

                case NANO_BLOCK_TYPE_RECEIVE:

                    dissect_nano_receive_block(tvb, nano_tree, offset);

                    break;

                case NANO_BLOCK_TYPE_SEND:

                    dissect_nano_send_block(tvb, nano_tree, offset);

                    break;

                case NANO_BLOCK_TYPE_OPEN:

                    dissect_nano_open_block(tvb, nano_tree, offset);

                    break;

                case NANO_BLOCK_TYPE_CHANGE:

                    dissect_nano_change_block(tvb, nano_tree, offset);

                    break;

                case NANO_BLOCK_TYPE_STATE:

                    dissect_nano_state(tvb, nano_tree, offset);

                    break;

            }

            break;

        default:

            col_add_str(pinfo->cinfo, COL_INFO,

                    val_to_str(pinfo->pool, nano_packet_type, VALS(nano_packet_type_strings), "Unknown (%d)"));

    }

    return tvb_captured_length(tvb);

}

// determine the length of a nano bootstrap message (client)

static unsigned get_nano_tcp_client_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)

{

    int nano_packet_type, nano_block_type;

    struct nano_session_state *session_state;

    session_state = (struct nano_session_state *)data;

    if (session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PUSH) {

        // we're in the middle of a bulk push, so we expect a block type (uint8) and a block

        nano_block_type = tvb_get_uint8(tvb, offset);

        switch (nano_block_type) {

            case NANO_BLOCK_TYPE_NOT_A_BLOCK:

                return 1;

            case NANO_BLOCK_TYPE_SEND:

                return 1 + NANO_BLOCK_SIZE_SEND;

            case NANO_BLOCK_TYPE_RECEIVE:

                return 1 + NANO_BLOCK_SIZE_RECEIVE;

            case NANO_BLOCK_TYPE_OPEN:

                return 1 + NANO_BLOCK_SIZE_OPEN;

            case NANO_BLOCK_TYPE_CHANGE:

                return 1 + NANO_BLOCK_SIZE_CHANGE;

            case NANO_BLOCK_TYPE_STATE:

                return 1 + NANO_BLOCK_SIZE_STATE;

            default:

                // this is invalid

                return tvb_captured_length(tvb) - offset;

        }

    }

    // we expect a client command, this starts with a full Nano header

    if (tvb_captured_length(tvb) - offset < NANO_HEADER_LENGTH) {

        return 0;

    }

    nano_packet_type = tvb_get_uint8(tvb, offset + 5);

    switch (nano_packet_type) {

        case NANO_PACKET_TYPE_BULK_PULL:

            return NANO_HEADER_LENGTH + 32 + 32;

        case NANO_PACKET_TYPE_BULK_PUSH:

            return NANO_HEADER_LENGTH;

        case NANO_PACKET_TYPE_FRONTIER_REQ:

            return NANO_HEADER_LENGTH + 32 + 4 + 4;

        case NANO_PACKET_TYPE_BULK_PULL_BLOCKS:

            return NANO_HEADER_LENGTH + 32 + 32 + 1 + 4;

    }

    return tvb_captured_length(tvb) - offset;

}

// dissect a bulk pull request

static int dissect_nano_bulk_pull(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *vote_tree;

    vote_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 32+32, ett_nano_bulk_pull, NULL, "Bulk Pull");

    proto_tree_add_item(vote_tree, hf_nano_bulk_pull_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(vote_tree, hf_nano_bulk_pull_block_hash_end, tvb, offset, 32, ENC_NA);

    offset += 32;

    return offset;

}

// dissect a frontier request

static int dissect_nano_frontier_req(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *vote_tree;

    vote_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 32+4+4, ett_nano_frontier_req, NULL, "Frontier Request");

    proto_tree_add_item(vote_tree, hf_nano_frontier_req_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(vote_tree, hf_nano_frontier_req_age, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    proto_tree_add_item(vote_tree, hf_nano_frontier_req_count, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    return offset;

}

// dissect a bulk pull blocks request

static int dissect_nano_bulk_pull_blocks(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *vote_tree;

    vote_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 32+4+4, ett_nano_frontier_req, NULL, "Bulk Pull Blocks");

    proto_tree_add_item(vote_tree, hf_nano_bulk_pull_blocks_min_hash, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(vote_tree, hf_nano_bulk_pull_blocks_max_hash, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(nano_tree, hf_nano_bulk_pull_blocks_mode, tvb, offset, 1, ENC_NA);

    offset += 1;

    proto_tree_add_item(vote_tree, hf_nano_bulk_pull_blocks_max_count, tvb, offset, 4, ENC_LITTLE_ENDIAN);

    offset += 4;

    return offset;

}

// dissect a single nano bootstrap message (client)

static int dissect_nano_tcp_client_message(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree _U_, void *data _U_)

{

    int offset;

    uint32_t nano_packet_type, nano_block_type;

    uint64_t extensions;

    struct nano_session_state *session_state;

    session_state = (struct nano_session_state *)data;

    if (session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PUSH) {

        // we're within a bulk push

        col_set_str(pinfo->cinfo, COL_INFO, "Bulk Push ");

        proto_tree_add_item_ret_uint(tree, hf_nano_bulk_push_block_type, tvb, 0, 1, ENC_NA, &nano_block_type);

        switch (nano_block_type) {

            case NANO_BLOCK_TYPE_NOT_A_BLOCK:

                session_state->client_packet_type = NANO_PACKET_TYPE_INVALID;

                break;

            case NANO_BLOCK_TYPE_SEND:

                dissect_nano_send_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_RECEIVE:

                dissect_nano_receive_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_OPEN:

                dissect_nano_open_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_CHANGE:

                dissect_nano_change_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_STATE:

                dissect_nano_state(tvb, tree, 1);

                break;

        }

        return tvb_captured_length(tvb);

    }

    // a bootstrap client command starts with a Nano header

    offset = dissect_nano_header(tvb, pinfo, tree, 0, &nano_packet_type, &extensions);

    session_state->client_packet_type = nano_packet_type;

    switch (nano_packet_type) {

        case NANO_PACKET_TYPE_BULK_PULL:

            col_set_str(pinfo->cinfo, COL_INFO, "Bulk Pull Request ");

            dissect_nano_bulk_pull(tvb, tree, offset);

            break;

        case NANO_PACKET_TYPE_BULK_PUSH:

            col_set_str(pinfo->cinfo, COL_INFO, "Bulk Push Request ");

            break;

        case NANO_PACKET_TYPE_FRONTIER_REQ:

            col_set_str(pinfo->cinfo, COL_INFO, "Frontier Request ");

            dissect_nano_frontier_req(tvb, tree, offset);

            break;

        case NANO_PACKET_TYPE_BULK_PULL_BLOCKS:

            col_set_str(pinfo->cinfo, COL_INFO, "Bulk Pull Blocks Request ");

            dissect_nano_bulk_pull_blocks(tvb, tree, offset);

            break;

    }

    return tvb_captured_length(tvb);

}

// determine the length of a nano bootstrap message (server)

static unsigned get_nano_tcp_server_message_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_)

{

    int nano_block_type;

    struct nano_session_state *session_state;

    session_state = (struct nano_session_state *)data;

    if (session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PULL ||

        session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PULL_BLOCKS) {

        // we're in response to a bulk pull (blocks), so we expect a block type (uint8) and a block

        nano_block_type = tvb_get_uint8(tvb, offset);

        switch (nano_block_type) {

            case NANO_BLOCK_TYPE_NOT_A_BLOCK:

                return 1;

            case NANO_BLOCK_TYPE_SEND:

                return 1 + NANO_BLOCK_SIZE_SEND;

            case NANO_BLOCK_TYPE_RECEIVE:

                return 1 + NANO_BLOCK_SIZE_RECEIVE;

            case NANO_BLOCK_TYPE_OPEN:

                return 1 + NANO_BLOCK_SIZE_OPEN;

            case NANO_BLOCK_TYPE_CHANGE:

                return 1 + NANO_BLOCK_SIZE_CHANGE;

            case NANO_BLOCK_TYPE_STATE:

                return 1 + NANO_BLOCK_SIZE_STATE;

            default:

                // this is invalid

                return tvb_captured_length(tvb) - offset;

        }

    }

    if (session_state->client_packet_type == NANO_PACKET_TYPE_FRONTIER_REQ) {

        return 32 + 32;

    }

    return tvb_captured_length(tvb) - offset;

}

// dissect a frontier response entry

static int dissect_nano_frontier(tvbuff_t *tvb, proto_tree *nano_tree, int offset)

{

    proto_tree *frontier_tree;

    frontier_tree = proto_tree_add_subtree(nano_tree, tvb, offset, 32+32, ett_nano_frontier, NULL, "Frontier");

    proto_tree_add_item(frontier_tree, hf_nano_frontier_account, tvb, offset, 32, ENC_NA);

    offset += 32;

    proto_tree_add_item(frontier_tree, hf_nano_frontier_head_hash, tvb, offset, 32, ENC_NA);

    offset += 32;

    return offset;

}

// dissect a single nano bootstrap message (server)

static int dissect_nano_tcp_server_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_)

{

    uint32_t nano_block_type;

    struct nano_session_state *session_state;

    session_state = (struct nano_session_state *)data;

    if (session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PULL ||

        session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PULL_BLOCKS) {

        // we're within a bulk pull (blocks)

        col_set_str(pinfo->cinfo, COL_INFO, session_state->client_packet_type == NANO_PACKET_TYPE_BULK_PULL ? "Bulk Pull Response " : "Bulk Pull Blocks Response ");

        proto_tree_add_item_ret_uint(tree, hf_nano_bulk_pull_block_type, tvb, 0, 1, ENC_NA, &nano_block_type);

        switch (nano_block_type) {

            case NANO_BLOCK_TYPE_NOT_A_BLOCK:

                session_state->client_packet_type = NANO_PACKET_TYPE_INVALID;

                break;

            case NANO_BLOCK_TYPE_SEND:

                dissect_nano_send_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_RECEIVE:

                dissect_nano_receive_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_OPEN:

                dissect_nano_open_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_CHANGE:

                dissect_nano_change_block(tvb, tree, 1);

                break;

            case NANO_BLOCK_TYPE_STATE:

                dissect_nano_state(tvb, tree, 1);

                break;

        }

        return tvb_captured_length(tvb);

    }

    if (session_state->client_packet_type == NANO_PACKET_TYPE_FRONTIER_REQ) {

        col_set_str(pinfo->cinfo, COL_INFO, "Frontier Response ");

        dissect_nano_frontier(tvb, tree, 0);

    }

    return tvb_captured_length(tvb);

}

// dissect a Nano bootstrap packet (TCP)

static int dissect_nano_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)

{

    int is_client;

    proto_item *ti;

    proto_tree *nano_tree;

    conversation_t *conversation;

    struct nano_session_state *session_state, *packet_session_state;

    // try to find this conversation

    if ((conversation = find_conversation_pinfo(pinfo, 0)) == NULL) {

        // create new conversation

        conversation = conversation_new(pinfo->num, &pinfo->src, &pinfo->dst, conversation_pt_to_conversation_type(pinfo->ptype),

                pinfo->srcport, pinfo->destport, 0);

    }

    // try to find session state

    session_state = (struct nano_session_state *)conversation_get_proto_data(conversation, proto_nano);

    if (!session_state) {

        // create new session state

        session_state = wmem_new0(wmem_file_scope(), struct nano_session_state);

        session_state->client_packet_type = NANO_PACKET_TYPE_INVALID;

        session_state->server_port = pinfo->match_uint;

        conversation_add_proto_data(conversation, proto_nano, session_state);

    }

    // check if we have a session state associated with the packet (start state for this packet)

    packet_session_state = (struct nano_session_state *)p_get_proto_data(wmem_file_scope(), pinfo, proto_nano, 0);

    if (!packet_session_state) {

        // this packet does not have a stored session state, get it from the conversation

        packet_session_state = wmem_new0(wmem_file_scope(), struct nano_session_state);

        memcpy(packet_session_state, session_state, sizeof(struct nano_session_state));

        p_add_proto_data(wmem_file_scope(), pinfo, proto_nano, 0, packet_session_state);

    } else {

        // this packet has a stored session state, take this as a starting point

        memcpy(session_state, packet_session_state, sizeof(struct nano_session_state));

    }

    // set some columns to meaningful defaults

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "Nano Bootstrap");

    col_clear(pinfo->cinfo, COL_INFO);

    // add Nano protocol tree

    ti = proto_tree_add_item(tree, proto_nano, tvb, 0, -1, ENC_NA);

    nano_tree = proto_item_add_subtree(ti, ett_nano);

    // is this a bootstrap client or server?

    is_client = pinfo->destport == session_state->server_port;

    if (is_client) {

        // Nano bootstrap client

        tcp_dissect_pdus(tvb, pinfo, nano_tree, true, 1, get_nano_tcp_client_message_len, dissect_nano_tcp_client_message, session_state);

    } else {

        // Nano bootstrap server

        tcp_dissect_pdus(tvb, pinfo, nano_tree, true, 1, get_nano_tcp_server_message_len, dissect_nano_tcp_server_message, session_state);

    }

    return tvb_captured_length(tvb);

}

/* Heuristics test */

static bool test_nano(packet_info *pinfo _U_, tvbuff_t *tvb, int offset _U_, void *data _U_)

{

    // if it's not a complete header length, it's not Nano.

    if (tvb_captured_length(tvb) < NANO_HEADER_LENGTH)

        return false;

    // first byte must be 'R', second byte 'A' or 'B' or 'C'

    if (tvb_get_uint8(tvb, 0) != (uint8_t) 'R')

        return false;

    char network = (char) tvb_get_uint8(tvb, 1);

    if (network != 'A' && network != 'B' && network != 'C')

        return false;

    uint8_t version_max = tvb_get_uint8(tvb, 2);

    uint8_t version_using = tvb_get_uint8(tvb, 3);

    uint8_t version_min = tvb_get_uint8(tvb, 4);

    if (version_max > 30 || version_max < version_using || version_using < version_min)

        return false;

    uint8_t ptype = tvb_get_uint8(tvb, 5);

    if (ptype > 15)

        return false;

    return true;

}

static bool dissect_nano_heur_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

    conversation_t *conversation;

    struct nano_session_state *session_state;

    if (!test_nano(pinfo, tvb, 0, data))

        return false;

    conversation = find_or_create_conversation(pinfo);

    conversation_set_dissector(conversation, nano_tcp_handle);

    // try to find session state

    session_state = (struct nano_session_state *)conversation_get_proto_data(conversation, proto_nano);

    if (!session_state) {

        // create new session state

        session_state = wmem_new0(wmem_file_scope(), struct nano_session_state);

        session_state->client_packet_type = NANO_PACKET_TYPE_INVALID;

        session_state->server_port = pinfo->destport;

        conversation_add_proto_data(conversation, proto_nano, session_state);

    }

    dissect_nano_tcp(tvb, pinfo, tree, data);

    return true;

}

static bool dissect_nano_heur_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)

{

    conversation_t *conversation;

    if (!test_nano(pinfo, tvb, 0, data))

        return false;

    conversation = find_or_create_conversation(pinfo);

    conversation_set_dissector(conversation, nano_handle);

    dissect_nano(tvb, pinfo, tree, data);

    return true;

}

void proto_register_nano(void)

{

    static hf_register_info hf[] = {

        { &hf_nano_magic_number,

          { "Magic Number", "nano.magic_number",

            FT_STRING, BASE_NONE, NULL, 0x00,

            "Nano Protocol Magic Number", HFILL }

        },

        { &hf_nano_version_max,

          { "Maximum Version", "nano.version_max",

            FT_UINT8, BASE_DEC_HEX, NULL, 0x00,

            "Maximum Supported Protocol Version", HFILL }

        },

        { &hf_nano_version_using,

          { "Using Version", "nano.version_using",

            FT_UINT8, BASE_DEC_HEX, NULL, 0x00,

            "Used Protocol Version", HFILL }

        },

        { &hf_nano_version_min,

          { "Minimum Version", "nano.version_min",

            FT_UINT8, BASE_DEC_HEX, NULL, 0x00,

            "Minimum Supported Protocol Version", HFILL }

        },

        { &hf_nano_packet_type,

          { "Packet Type", "nano.packet_type",

            FT_UINT8, BASE_DEC_HEX, VALS(nano_packet_type_strings), 0x00,

            NULL, HFILL }

        },

        { &hf_nano_extensions,

          { "Extensions Field", "nano.extensions",

            FT_UINT16, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_extensions_block_type,

          { "Block Type", "nano.extensions.block_type",

            FT_UINT16, BASE_HEX, VALS(nano_block_type_strings), 0x0f00,

            NULL, HFILL }

        },

        { &hf_nano_keepalive_peer_ip,

          { "Peer IP Address", "nano.keepalive.peer_ip",

            FT_IPv6, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_keepalive_peer_port,

          { "Peer Port", "nano.keepalive.peer_port",

            FT_UINT16, BASE_DEC, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_hash_previous,

          { "Previous Block Hash", "nano.block.hash_previous",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_hash_source,

          { "Source Block Hash", "nano.block.hash_source",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_signature,

          { "Signature", "nano.block.signature",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_work,

          { "Work", "nano.block.work",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_destination_account,

          { "Destination Account", "nano.block.destination_account",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_balance,

          { "Balance", "nano.block.balance",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_account,

          { "Account", "nano.block.account",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_representative_account,

          { "Representative Account", "nano.block.representative_account",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_block_link,

          { "Link", "nano.block.link",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_vote_account,

          { "Account", "nano.vote.account",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_vote_signature,

          { "Signature", "nano.vote.signature",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_vote_sequence,

          { "Sequence", "nano.vote.sequence",

            FT_UINT64, BASE_DEC_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_bulk_pull_account,

          { "Account", "nano.bulk_pull.account",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_nano_bulk_pull_block_hash_end,