blob: cd845d7e7d6ed722f5ef58a486268351e9a5b646 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
/*
Copyright (C) 2013 Matthias P. Braendli
http://mpb.li
EDI output.
This implements an AF Packet as defined ETSI TS 102 821.
Also see ETSI TS 102 693
*/
/*
This file is part of CRC-DabMux.
CRC-DabMux is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
CRC-DabMux is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with CRC-DabMux. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "crc.h"
#include "AFPacket.h"
#include <vector>
#include <string>
#include <stdint.h>
#include <arpa/inet.h>
// Header PT field. AF packet contains TAG payload
#define AFHEADER_PT_TAG 'T'
// AF Packet Major (3 bits) and Minor (4 bits) version
#define AFHEADER_VERSION 0x8 // MAJ=1, MIN=0
std::vector<uint8_t> AFPacket::Assemble(char protocol_type, std::vector<uint8_t> payload)
{
header.ar_maj = 1;
header.ar_min = 0;
header.pt = protocol_type;
std::string pack_data("AF"); // SYNC
std::vector<uint8_t> packet(pack_data.begin(), pack_data.end());
uint32_t taglength = payload.size();
// write length into packet
packet[2] = (taglength >> 24) & 0xFF;
packet[3] = (taglength >> 16) & 0xFF;
packet[4] = (taglength >> 8) & 0xFF;
packet[5] = taglength & 0xFF;
// fill rest of header
packet.push_back(seq >> 8);
packet.push_back(seq & 0xFF);
packet.push_back((have_crc ? 0x80 : 0) | AFHEADER_VERSION); // ar_cf: CRC=1
packet.push_back(AFHEADER_PT_TAG);
// insert payload
packet.insert(packet.end(), payload.begin(), payload.end());
// calculate CRC over AF Header and payload
uint16_t crc = 0xffff;
crc = crc16(crc, &(packet.back()), packet.size());
crc ^= 0xffff;
crc = htons(crc);
packet.push_back((crc >> 24) & 0xFF);
packet.push_back((crc >> 16) & 0xFF);
packet.push_back((crc >> 8) & 0xFF);
packet.push_back(crc & 0xFF);
return packet;
}
|
