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| author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2021-01-15 08:22:18 +0100 | 
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| committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2021-01-15 08:22:18 +0100 | 
| commit | 9d6ddfcb36115084237bac3a3f1c49ddf0da765f (patch) | |
| tree | 6b828d92034a3322f9109663be32ff2646009d1f /lib/edi/PFT.cpp | |
| parent | b65ec3d9d712c23f99f6af6a85aa421a98b4c8a0 (diff) | |
| download | ODR-SourceCompanion-9d6ddfcb36115084237bac3a3f1c49ddf0da765f.tar.gz ODR-SourceCompanion-9d6ddfcb36115084237bac3a3f1c49ddf0da765f.tar.bz2 ODR-SourceCompanion-9d6ddfcb36115084237bac3a3f1c49ddf0da765f.zip | |
Common 6b5db53: Update zmq.hpp, TCPReceiveServer, EDI decoder and output
Diffstat (limited to 'lib/edi/PFT.cpp')
| -rw-r--r-- | lib/edi/PFT.cpp | 325 | 
1 files changed, 0 insertions, 325 deletions
| diff --git a/lib/edi/PFT.cpp b/lib/edi/PFT.cpp deleted file mode 100644 index 1e3d4da..0000000 --- a/lib/edi/PFT.cpp +++ /dev/null @@ -1,325 +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 the ODR-mmbTools. - -   This program 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. - -   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. - */ - -#include "config.h" -#include <vector> -#include <list> -#include <cstdio> -#include <cstring> -#include <cstdint> -#include <arpa/inet.h> -#include <stdexcept> -#include <sstream> -#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<uint8_t> chunk(207); -        vector<uint8_t> 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<uint8_t> > 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<uint8_t> > 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<uint8_t> > 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<uint8_t> > fragments = ProtectAndFragment(af_packet); -    vector< vector<uint8_t> > pft_fragments; // These contain PF headers - -    const bool enable_RS = (m_m > 0); - -    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<uint8_t> 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 (m_transport_header) { -            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 (m_transport_header) { -            // Source (16 bits) -            packet.push_back(m_addr_source >> 8); -            packet.push_back(m_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; -} - -} - | 
