From 5ee85c4ac41337e383eb1a735bc05f1e5d46a98f Mon Sep 17 00:00:00 2001 From: "Matthias P. Braendli" Date: Mon, 19 Aug 2019 17:18:51 +0200 Subject: Use EDI output from odr-mmbtools-common --- src/dabOutput/edi/PFT.cpp | 327 ---------------------------------------------- 1 file changed, 327 deletions(-) delete mode 100644 src/dabOutput/edi/PFT.cpp (limited to 'src/dabOutput/edi/PFT.cpp') diff --git a/src/dabOutput/edi/PFT.cpp b/src/dabOutput/edi/PFT.cpp deleted file mode 100644 index 63dfa34..0000000 --- a/src/dabOutput/edi/PFT.cpp +++ /dev/null @@ -1,327 +0,0 @@ -/* - Copyright (C) 2019 - Matthias P. Braendli, matthias.braendli@mpb.li - - http://www.opendigitalradio.org - - EDI output, - Protection, Fragmentation and Transport. (PFT) - - Are supported: - Reed-Solomon and Fragmentation - - This implements part of PFT as defined ETSI TS 102 821. - - */ -/* - This file is part of ODR-DabMux. - - ODR-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. - - ODR-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 ODR-DabMux. If not, see . - */ - -#include "config.h" -#include -#include -#include -#include -#include -#include -#include -#include -#include "PFT.h" -#include "crc.h" -#include "ReedSolomon.h" - -namespace edi { - -using namespace std; - -// An integer division that rounds up, i.e. ceil(a/b) -#define CEIL_DIV(a, b) (a % b == 0 ? a / b : a / b + 1) - -PFT::PFT() { } - -PFT::PFT(const configuration_t &conf) : - m_k(conf.chunk_len), - m_m(conf.fec), - m_dest_port(conf.dest_port), - m_pseq(0), - m_num_chunks(0), - m_verbose(conf.verbose) - { - if (m_k > 207) { - etiLog.level(warn) << - "EDI PFT: maximum chunk size is 207."; - throw std::out_of_range("EDI PFT Chunk size too large."); - } - - if (m_m > 5) { - etiLog.level(warn) << - "EDI PFT: high number of recoverable fragments" - " may lead to large overhead"; - // See TS 102 821, 7.2.1 Known values, list entry for 'm' - } - } - -RSBlock PFT::Protect(AFPacket af_packet) -{ - RSBlock rs_block; - - // number of chunks is ceil(afpacketsize / m_k) - // TS 102 821 7.2.2: c = ceil(l / k_max) - m_num_chunks = CEIL_DIV(af_packet.size(), m_k); - - if (m_verbose) { - fprintf(stderr, "Protect %zu chunks of size %zu\n", - m_num_chunks, af_packet.size()); - } - - // calculate size of chunk: - // TS 102 821 7.2.2: k = ceil(l / c) - // chunk_len does not include the 48 bytes of protection. - const size_t chunk_len = CEIL_DIV(af_packet.size(), m_num_chunks); - if (chunk_len > 207) { - std::stringstream ss; - ss << "Chunk length " << chunk_len << " too large (>207)"; - throw std::runtime_error(ss.str()); - } - - // The last RS chunk is zero padded - // TS 102 821 7.2.2: z = c*k - l - const size_t zero_pad = m_num_chunks * chunk_len - af_packet.size(); - - // Create the RS(k+p,k) encoder - const int firstRoot = 1; // Discovered by analysing EDI dump - const int gfPoly = 0x11d; - const bool reverse = false; - // The encoding has to be 255, 207 always, because the chunk has to - // be padded at the end, and not at the beginning as libfec would - // do - ReedSolomon rs_encoder(255, 207, reverse, gfPoly, firstRoot); - - // add zero padding to last chunk - for (size_t i = 0; i < zero_pad; i++) { - af_packet.push_back(0); - } - - if (m_verbose) { - fprintf(stderr, " add %zu zero padding\n", zero_pad); - } - - // Calculate RS for each chunk and assemble RS block - for (size_t i = 0; i < af_packet.size(); i+= chunk_len) { - vector chunk(207); - vector protection(PARITYBYTES); - - // copy chunk_len bytes into new chunk - memcpy(&chunk.front(), &af_packet[i], chunk_len); - - // calculate RS for chunk with padding - rs_encoder.encode(&chunk.front(), &protection.front(), 207); - - // Drop the padding - chunk.resize(chunk_len); - - // append new chunk and protection to the RS Packet - rs_block.insert(rs_block.end(), chunk.begin(), chunk.end()); - rs_block.insert(rs_block.end(), protection.begin(), protection.end()); - } - - return rs_block; -} - -vector< vector > PFT::ProtectAndFragment(AFPacket af_packet) -{ - const bool enable_RS = (m_m > 0); - - if (enable_RS) { - RSBlock rs_block = Protect(af_packet); - -#if 0 - fprintf(stderr, " af_packet (%zu):", af_packet.size()); - for (size_t i = 0; i < af_packet.size(); i++) { - fprintf(stderr, "%02x ", af_packet[i]); - } - fprintf(stderr, "\n"); - - fprintf(stderr, " rs_block (%zu):", rs_block.size()); - for (size_t i = 0; i < rs_block.size(); i++) { - fprintf(stderr, "%02x ", rs_block[i]); - } - fprintf(stderr, "\n"); -#endif - - // TS 102 821 7.2.2: s_max = MIN(floor(c*p/(m+1)), MTU - h)) - const size_t max_payload_size = ( m_num_chunks * PARITYBYTES ) / (m_m + 1); - - // Calculate fragment count and size - // TS 102 821 7.2.2: ceil((l + c*p + z) / s_max) - // l + c*p + z = length of RS block - const size_t num_fragments = CEIL_DIV(rs_block.size(), max_payload_size); - - // TS 102 821 7.2.2: ceil((l + c*p + z) / f) - const size_t fragment_size = CEIL_DIV(rs_block.size(), num_fragments); - - if (m_verbose) - fprintf(stderr, " PnF fragment_size %zu, num frag %zu\n", - fragment_size, num_fragments); - - vector< vector > fragments(num_fragments); - - for (size_t i = 0; i < num_fragments; i++) { - fragments[i].resize(fragment_size); - for (size_t j = 0; j < fragment_size; j++) { - const size_t ix = j*num_fragments + i; - if (ix < rs_block.size()) { - fragments[i][j] = rs_block[ix]; - } - else { - fragments[i][j] = 0; - } - } - } - - return fragments; - } - else { // No RS, only fragmentation - // TS 102 821 7.2.2: s_max = MTU - h - // Ethernet MTU is 1500, but maybe you are routing over a network which - // has some sort of packet encapsulation. Add some margin. - const size_t max_payload_size = 1400; - - // Calculate fragment count and size - // TS 102 821 7.2.2: ceil((l + c*p + z) / s_max) - // l + c*p + z = length of AF packet - const size_t num_fragments = CEIL_DIV(af_packet.size(), max_payload_size); - - // TS 102 821 7.2.2: ceil((l + c*p + z) / f) - const size_t fragment_size = CEIL_DIV(af_packet.size(), num_fragments); - vector< vector > fragments(num_fragments); - - for (size_t i = 0; i < num_fragments; i++) { - fragments[i].reserve(fragment_size); - - for (size_t j = 0; j < fragment_size; j++) { - const size_t ix = i*fragment_size + j; - if (ix < af_packet.size()) { - fragments[i].push_back(af_packet.at(ix)); - } - else { - break; - } - } - } - - return fragments; - } -} - -std::vector< PFTFragment > PFT::Assemble(AFPacket af_packet) -{ - vector< vector > fragments = ProtectAndFragment(af_packet); - vector< vector > pft_fragments; // These contain PF headers - - const bool enable_RS = (m_m > 0); - const bool enable_transport = true; - - unsigned int findex = 0; - - unsigned fcount = fragments.size(); - - // calculate size of chunk: - // TS 102 821 7.2.2: k = ceil(l / c) - // chunk_len does not include the 48 bytes of protection. - const size_t chunk_len = enable_RS ? - CEIL_DIV(af_packet.size(), m_num_chunks) : 0; - - // The last RS chunk is zero padded - // TS 102 821 7.2.2: z = c*k - l - const size_t zero_pad = enable_RS ? - m_num_chunks * chunk_len - af_packet.size() : 0; - - for (const auto &fragment : fragments) { - // Psync - std::string psync("PF"); - std::vector packet(psync.begin(), psync.end()); - - // Pseq - packet.push_back(m_pseq >> 8); - packet.push_back(m_pseq & 0xFF); - - // Findex - packet.push_back(findex >> 16); - packet.push_back(findex >> 8); - packet.push_back(findex & 0xFF); - findex++; - - // Fcount - packet.push_back(fcount >> 16); - packet.push_back(fcount >> 8); - packet.push_back(fcount & 0xFF); - - // RS (1 bit), transport (1 bit) and Plen (14 bits) - unsigned int plen = fragment.size(); - if (enable_RS) { - plen |= 0x8000; // Set FEC bit - } - - if (enable_transport) { - plen |= 0x4000; // Set ADDR bit - } - - packet.push_back(plen >> 8); - packet.push_back(plen & 0xFF); - - if (enable_RS) { - packet.push_back(chunk_len); // RSk - packet.push_back(zero_pad); // RSz - } - - if (enable_transport) { - // Source (16 bits) - uint16_t addr_source = 0; - packet.push_back(addr_source >> 8); - packet.push_back(addr_source & 0xFF); - - // Dest (16 bits) - packet.push_back(m_dest_port >> 8); - packet.push_back(m_dest_port & 0xFF); - } - - // calculate CRC over AF Header and payload - uint16_t crc = 0xffff; - crc = crc16(crc, &(packet.front()), packet.size()); - crc ^= 0xffff; - - packet.push_back((crc >> 8) & 0xFF); - packet.push_back(crc & 0xFF); - - // insert payload, must have a length multiple of 8 bytes - packet.insert(packet.end(), fragment.begin(), fragment.end()); - - pft_fragments.push_back(packet); - -#if 0 - fprintf(stderr, "* PFT pseq %d, findex %d, fcount %d, plen %d\n", - m_pseq, findex, fcount, plen & ~0xC000); -#endif - } - - m_pseq++; - - return pft_fragments; -} - -} - -- cgit v1.2.3