Replace socket library

3 files changed, 1364 insertions, 0 deletions

diff --git a/lib/Socket.cpp b/lib/Socket.cpp
new file mode 100644
index 0000000..d14902e
--- /dev/null
+++ b/lib/Socket.cpp
@@ -0,0 +1,894 @@
+/*
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Her Majesty the
+   Queen in Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2019
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://www.opendigitalradio.org
+   */
+/*
+   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 <https://www.gnu.org/licenses/>.
+*/
+
+#include "Socket.h"
+
+#include <iostream>
+#include <cstdio>
+#include <cstring>
+#include <cerrno>
+#include <fcntl.h>
+#include <poll.h>
+
+namespace Socket {
+
+using namespace std;
+
+void InetAddress::resolveUdpDestination(const std::string& destination, int port)
+{
+    char service[NI_MAXSERV];
+    snprintf(service, NI_MAXSERV-1, "%d", port);
+
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_DGRAM; /* Datagram socket */
+    hints.ai_flags = 0;
+    hints.ai_protocol = 0;
+
+    struct addrinfo *result, *rp;
+    int s = getaddrinfo(destination.c_str(), service, &hints, &result);
+    if (s != 0) {
+        throw runtime_error(string("getaddrinfo failed: ") + gai_strerror(s));
+    }
+
+    for (rp = result; rp != nullptr; rp = rp->ai_next) {
+        // Take the first result
+        memcpy(&addr, rp->ai_addr, rp->ai_addrlen);
+        break;
+    }
+
+    freeaddrinfo(result);
+
+    if (rp == nullptr) {
+        throw runtime_error("Could not resolve");
+    }
+}
+
+UDPPacket::UDPPacket() { }
+
+UDPPacket::UDPPacket(size_t initSize) :
+    buffer(initSize)
+{ }
+
+
+UDPSocket::UDPSocket() :
+    m_sock(INVALID_SOCKET)
+{
+    reinit(0, "");
+}
+
+UDPSocket::UDPSocket(int port) :
+    m_sock(INVALID_SOCKET)
+{
+    reinit(port, "");
+}
+
+UDPSocket::UDPSocket(int port, const std::string& name) :
+    m_sock(INVALID_SOCKET)
+{
+    reinit(port, name);
+}
+
+
+void UDPSocket::setBlocking(bool block)
+{
+    int res = fcntl(m_sock, F_SETFL, block ? 0 : O_NONBLOCK);
+    if (res == -1) {
+        throw runtime_error(string("Can't change blocking state of socket: ") + strerror(errno));
+    }
+}
+
+void UDPSocket::reinit(int port)
+{
+    return reinit(port, "");
+}
+
+void UDPSocket::reinit(int port, const std::string& name)
+{
+    if (m_sock != INVALID_SOCKET) {
+        ::close(m_sock);
+    }
+
+    if (port == 0) {
+        // No need to bind to a given port, creating the
+        // socket is enough
+        m_sock = ::socket(AF_INET, SOCK_DGRAM, 0);
+        return;
+    }
+
+    char service[NI_MAXSERV];
+    snprintf(service, NI_MAXSERV-1, "%d", port);
+
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_DGRAM; /* Datagram socket */
+    hints.ai_flags = AI_PASSIVE;    /* For wildcard IP address */
+    hints.ai_protocol = 0;          /* Any protocol */
+    hints.ai_canonname = nullptr;
+    hints.ai_addr = nullptr;
+    hints.ai_next = nullptr;
+
+    struct addrinfo *result, *rp;
+    int s = getaddrinfo(name.empty() ? nullptr : name.c_str(),
+            port == 0 ? nullptr : service,
+            &hints, &result);
+    if (s != 0) {
+        throw runtime_error(string("getaddrinfo failed: ") + gai_strerror(s));
+    }
+
+    /* getaddrinfo() returns a list of address structures.
+       Try each address until we successfully bind(2).
+       If socket(2) (or bind(2)) fails, we (close the socket
+       and) try the next address. */
+    for (rp = result; rp != nullptr; rp = rp->ai_next) {
+        int sfd = ::socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (sfd == -1) {
+            continue;
+        }
+
+        if (::bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) {
+            m_sock = sfd;
+            break;
+        }
+
+        ::close(sfd);
+    }
+
+    freeaddrinfo(result);
+
+    if (rp == nullptr) {
+        throw runtime_error("Could not bind");
+    }
+}
+
+void UDPSocket::close()
+{
+    if (m_sock != INVALID_SOCKET) {
+        ::close(m_sock);
+    }
+
+    m_sock = INVALID_SOCKET;
+}
+
+UDPSocket::~UDPSocket()
+{
+    if (m_sock != INVALID_SOCKET) {
+        ::close(m_sock);
+    }
+}
+
+
+UDPPacket UDPSocket::receive(size_t max_size)
+{
+    UDPPacket packet(max_size);
+    socklen_t addrSize;
+    addrSize = sizeof(*packet.address.as_sockaddr());
+    ssize_t ret = recvfrom(m_sock,
+            packet.buffer.data(),
+            packet.buffer.size(),
+            0,
+            packet.address.as_sockaddr(),
+            &addrSize);
+
+    if (ret == SOCKET_ERROR) {
+        packet.buffer.resize(0);
+
+        // This suppresses the -Wlogical-op warning
+#if EAGAIN == EWOULDBLOCK
+        if (errno == EAGAIN) {
+#else
+        if (errno == EAGAIN or errno == EWOULDBLOCK) {
+#endif
+            return 0;
+        }
+        throw runtime_error(string("Can't receive data: ") + strerror(errno));
+    }
+
+    packet.buffer.resize(ret);
+    return packet;
+}
+
+void UDPSocket::send(UDPPacket& packet)
+{
+    const int ret = sendto(m_sock, packet.buffer.data(), packet.buffer.size(), 0,
+            packet.address.as_sockaddr(), sizeof(*packet.address.as_sockaddr()));
+    if (ret == SOCKET_ERROR && errno != ECONNREFUSED) {
+        throw runtime_error(string("Can't send UDP packet: ") + strerror(errno));
+    }
+}
+
+
+void UDPSocket::send(const std::vector<uint8_t>& data, InetAddress destination)
+{
+    const int ret = sendto(m_sock, data.data(), data.size(), 0,
+            destination.as_sockaddr(), sizeof(*destination.as_sockaddr()));
+    if (ret == SOCKET_ERROR && errno != ECONNREFUSED) {
+        throw runtime_error(string("Can't send UDP packet: ") + strerror(errno));
+    }
+}
+
+void UDPSocket::joinGroup(const char* groupname, const char* if_addr)
+{
+    ip_mreqn group;
+    if ((group.imr_multiaddr.s_addr = inet_addr(groupname)) == INADDR_NONE) {
+        throw runtime_error("Cannot convert multicast group name");
+    }
+    if (!IN_MULTICAST(ntohl(group.imr_multiaddr.s_addr))) {
+        throw runtime_error("Group name is not a multicast address");
+    }
+
+    if (if_addr) {
+        group.imr_address.s_addr = inet_addr(if_addr);
+    }
+    else {
+        group.imr_address.s_addr = htons(INADDR_ANY);
+    }
+    group.imr_ifindex = 0;
+    if (setsockopt(m_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &group, sizeof(group))
+            == SOCKET_ERROR) {
+        throw runtime_error(string("Can't join multicast group") + strerror(errno));
+    }
+}
+
+void UDPSocket::setMulticastSource(const char* source_addr)
+{
+    struct in_addr addr;
+    if (inet_aton(source_addr, &addr) == 0) {
+        throw runtime_error(string("Can't parse source address") + strerror(errno));
+    }
+
+    if (setsockopt(m_sock, IPPROTO_IP, IP_MULTICAST_IF, &addr, sizeof(addr))
+            == SOCKET_ERROR) {
+        throw runtime_error(string("Can't set source address") + strerror(errno));
+    }
+}
+
+void UDPSocket::setMulticastTTL(int ttl)
+{
+    if (setsockopt(m_sock, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl))
+            == SOCKET_ERROR) {
+        throw runtime_error(string("Can't set multicast ttl") + strerror(errno));
+    }
+}
+
+UDPReceiver::UDPReceiver() { }
+
+UDPReceiver::~UDPReceiver() {
+    m_stop = true;
+    m_sock.close();
+    if (m_thread.joinable()) {
+        m_thread.join();
+    }
+}
+
+void UDPReceiver::start(int port, const string& bindto, const string& mcastaddr, size_t max_packets_queued) {
+    m_port = port;
+    m_bindto = bindto;
+    m_mcastaddr = mcastaddr;
+    m_max_packets_queued = max_packets_queued;
+    m_thread = std::thread(&UDPReceiver::m_run, this);
+}
+
+std::vector<uint8_t> UDPReceiver::get_packet_buffer()
+{
+    if (m_stop) {
+        throw runtime_error("UDP Receiver not running");
+    }
+
+    UDPPacket p;
+    m_packets.wait_and_pop(p);
+
+    return p.buffer;
+}
+
+void UDPReceiver::m_run()
+{
+    // Ensure that stop is set to true in case of exception or return
+    struct SetStopOnDestruct {
+        SetStopOnDestruct(atomic<bool>& stop) : m_stop(stop) {}
+        ~SetStopOnDestruct() { m_stop = true; }
+        private: atomic<bool>& m_stop;
+    } autoSetStop(m_stop);
+
+    if (IN_MULTICAST(ntohl(inet_addr(m_mcastaddr.c_str())))) {
+        m_sock.reinit(m_port, m_mcastaddr);
+        m_sock.setMulticastSource(m_bindto.c_str());
+        m_sock.joinGroup(m_mcastaddr.c_str(), m_bindto.c_str());
+    }
+    else {
+        m_sock.reinit(m_port, m_bindto);
+    }
+
+    while (not m_stop) {
+        constexpr size_t packsize = 8192;
+        try {
+            auto packet = m_sock.receive(packsize);
+            if (packet.buffer.size() == packsize) {
+                // TODO replace fprintf
+                fprintf(stderr, "Warning, possible UDP truncation\n");
+            }
+
+            // If this blocks, the UDP socket will lose incoming packets
+            m_packets.push_wait_if_full(packet, m_max_packets_queued);
+        }
+        catch (const std::runtime_error& e) {
+            // TODO replace fprintf
+            // TODO handle intr
+            fprintf(stderr, "Socket error: %s\n", e.what());
+            m_stop = true;
+        }
+    }
+}
+
+
+TCPSocket::TCPSocket()
+{
+}
+
+TCPSocket::~TCPSocket()
+{
+    if (m_sock != -1) {
+        ::close(m_sock);
+    }
+}
+
+TCPSocket::TCPSocket(TCPSocket&& other) :
+    m_sock(other.m_sock),
+    m_remote_address(move(other.m_remote_address))
+{
+    if (other.m_sock != -1) {
+        other.m_sock = -1;
+    }
+}
+
+TCPSocket& TCPSocket::operator=(TCPSocket&& other)
+{
+    swap(m_remote_address, other.m_remote_address);
+
+    m_sock = other.m_sock;
+    if (other.m_sock != -1) {
+        other.m_sock = -1;
+    }
+
+    return *this;
+}
+
+bool TCPSocket::valid() const
+{
+    return m_sock != -1;
+}
+
+void TCPSocket::connect(const std::string& hostname, int port)
+{
+    if (m_sock != INVALID_SOCKET) {
+        throw std::logic_error("You may only connect an invalid TCPSocket");
+    }
+
+    char service[NI_MAXSERV];
+    snprintf(service, NI_MAXSERV-1, "%d", port);
+
+    /* Obtain address(es) matching host/port */
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = 0;
+    hints.ai_protocol = 0;
+
+    struct addrinfo *result, *rp;
+    int s = getaddrinfo(hostname.c_str(), service, &hints, &result);
+    if (s != 0) {
+        throw runtime_error(string("getaddrinfo failed: ") + gai_strerror(s));
+    }
+
+    /* getaddrinfo() returns a list of address structures.
+       Try each address until we successfully connect(2).
+       If socket(2) (or connect(2)) fails, we (close the socket
+       and) try the next address. */
+
+    for (rp = result; rp != nullptr; rp = rp->ai_next) {
+        int sfd = ::socket(rp->ai_family, rp->ai_socktype,
+                rp->ai_protocol);
+        if (sfd == -1)
+            continue;
+
+        int ret = ::connect(sfd, rp->ai_addr, rp->ai_addrlen);
+        if (ret != -1 or (ret == -1 and errno == EINPROGRESS)) {
+            // As the TCPClient could set the socket to nonblocking, we
+            // must handle EINPROGRESS here
+            m_sock = sfd;
+            break;
+        }
+
+        ::close(sfd);
+    }
+
+    if (m_sock != INVALID_SOCKET) {
+#if defined(HAVE_SO_NOSIGPIPE)
+        int val = 1;
+        if (setsockopt(m_sock, SOL_SOCKET, SO_NOSIGPIPE, &val, sizeof(val))
+                == SOCKET_ERROR) {
+            throw std::runtime_error("Can't set SO_NOSIGPIPE");
+        }
+#endif
+    }
+
+    freeaddrinfo(result);           /* No longer needed */
+
+    if (rp == nullptr) {
+        throw runtime_error("Could not connect");
+    }
+
+}
+
+void TCPSocket::listen(int port, const string& name)
+{
+    if (m_sock != INVALID_SOCKET) {
+        throw std::logic_error("You may only listen with an invalid TCPSocket");
+    }
+
+    char service[NI_MAXSERV];
+    snprintf(service, NI_MAXSERV-1, "%d", port);
+
+    struct addrinfo hints;
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;    /* For wildcard IP address */
+    hints.ai_protocol = 0;
+    hints.ai_canonname = nullptr;
+    hints.ai_addr = nullptr;
+    hints.ai_next = nullptr;
+
+    struct addrinfo *result, *rp;
+    int s = getaddrinfo(name.empty() ? nullptr : name.c_str(), service, &hints, &result);
+    if (s != 0) {
+        throw runtime_error(string("getaddrinfo failed: ") + gai_strerror(s));
+    }
+
+    /* getaddrinfo() returns a list of address structures.
+       Try each address until we successfully bind(2).
+       If socket(2) (or bind(2)) fails, we (close the socket
+       and) try the next address. */
+    for (rp = result; rp != nullptr; rp = rp->ai_next) {
+        int sfd = ::socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (sfd == -1) {
+            continue;
+        }
+
+        if (::bind(sfd, rp->ai_addr, rp->ai_addrlen) == 0) {
+            m_sock = sfd;
+            break;
+        }
+
+        ::close(sfd);
+    }
+
+    freeaddrinfo(result);
+
+    if (m_sock != INVALID_SOCKET) {
+#if defined(HAVE_SO_NOSIGPIPE)
+        int val = 1;
+        if (setsockopt(m_sock, SOL_SOCKET, SO_NOSIGPIPE,
+                    &val, sizeof(val)) < 0) {
+            throw std::runtime_error("Can't set SO_NOSIGPIPE");
+        }
+#endif
+
+        int ret = ::listen(m_sock, 0);
+        if (ret == -1) {
+            throw std::runtime_error(string("Could not listen: ") + strerror(errno));
+        }
+    }
+
+    if (rp == nullptr) {
+        throw runtime_error("Could not bind");
+    }
+}
+
+void TCPSocket::close()
+{
+    ::close(m_sock);
+    m_sock = -1;
+}
+
+TCPSocket TCPSocket::accept(int timeout_ms)
+{
+    if (timeout_ms == 0) {
+        InetAddress remote_addr;
+        socklen_t client_len = sizeof(remote_addr.addr);
+        int sockfd = ::accept(m_sock, remote_addr.as_sockaddr(), &client_len);
+        TCPSocket s(sockfd, remote_addr);
+        return s;
+    }
+    else {
+        struct pollfd fds[1];
+        fds[0].fd = m_sock;
+        fds[0].events = POLLIN;
+
+        int retval = poll(fds, 1, timeout_ms);
+
+        if (retval == -1) {
+            std::string errstr(strerror(errno));
+            throw std::runtime_error("TCP Socket accept error: " + errstr);
+        }
+        else if (retval > 0) {
+            InetAddress remote_addr;
+            socklen_t client_len = sizeof(remote_addr.addr);
+            int sockfd = ::accept(m_sock, remote_addr.as_sockaddr(), &client_len);
+            TCPSocket s(sockfd, remote_addr);
+            return s;
+        }
+        else {
+            TCPSocket s(-1);
+            return s;
+        }
+    }
+}
+
+ssize_t TCPSocket::sendall(const void *buffer, size_t buflen)
+{
+    uint8_t *buf = (uint8_t*)buffer;
+    while (buflen > 0) {
+        /* On Linux, the MSG_NOSIGNAL flag ensures that the process
+         * would not receive a SIGPIPE and die.
+         * Other systems have SO_NOSIGPIPE set on the socket for the
+         * same effect. */
+#if defined(HAVE_MSG_NOSIGNAL)
+        const int flags = MSG_NOSIGNAL;
+#else
+        const int flags = 0;
+#endif
+        ssize_t sent = ::send(m_sock, buf, buflen, flags);
+        if (sent < 0) {
+            return -1;
+        }
+        else {
+            buf += sent;
+            buflen -= sent;
+        }
+    }
+    return buflen;
+}
+
+ssize_t TCPSocket::send(const void* data, size_t size, int timeout_ms)
+{
+    if (timeout_ms) {
+        struct pollfd fds[1];
+        fds[0].fd = m_sock;
+        fds[0].events = POLLOUT;
+
+        const int retval = poll(fds, 1, timeout_ms);
+
+        if (retval == -1) {
+            throw std::runtime_error(string("TCP Socket send error on poll(): ") + strerror(errno));
+        }
+        else if (retval == 0) {
+            // Timed out
+            return 0;
+        }
+    }
+
+    /* On Linux, the MSG_NOSIGNAL flag ensures that the process would not
+     * receive a SIGPIPE and die.
+     * Other systems have SO_NOSIGPIPE set on the socket for the same effect. */
+#if defined(HAVE_MSG_NOSIGNAL)
+    const int flags = MSG_NOSIGNAL;
+#else
+    const int flags = 0;
+#endif
+    const ssize_t ret = ::send(m_sock, (const char*)data, size, flags);
+
+    if (ret == SOCKET_ERROR) {
+            throw std::runtime_error(string("TCP Socket send error: ") + strerror(errno));
+    }
+    return ret;
+}
+
+ssize_t TCPSocket::recv(void *buffer, size_t length, int flags)
+{
+    ssize_t ret = ::recv(m_sock, buffer, length, flags);
+    if (ret == -1) {
+        std::string errstr(strerror(errno));
+        throw std::runtime_error("TCP receive error: " + errstr);
+    }
+    return ret;
+}
+
+ssize_t TCPSocket::recv(void *buffer, size_t length, int flags, int timeout_ms)
+{
+    struct pollfd fds[1];
+    fds[0].fd = m_sock;
+    fds[0].events = POLLIN;
+
+    int retval = poll(fds, 1, timeout_ms);
+
+    if (retval == -1 and errno == EINTR) {
+        throw Interrupted();
+    }
+    else if (retval == -1) {
+        std::string errstr(strerror(errno));
+        throw std::runtime_error("TCP receive with poll() error: " + errstr);
+    }
+    else if (retval > 0 and (fds[0].revents | POLLIN)) {
+        ssize_t ret = ::recv(m_sock, buffer, length, flags);
+        if (ret == -1) {
+            if (errno == ECONNREFUSED) {
+                return 0;
+            }
+            std::string errstr(strerror(errno));
+            throw std::runtime_error("TCP receive after poll() error: " + errstr);
+        }
+        return ret;
+    }
+    else {
+        throw Timeout();
+    }
+}
+
+TCPSocket::TCPSocket(int sockfd) :
+    m_sock(sockfd),
+    m_remote_address()
+{ }
+
+TCPSocket::TCPSocket(int sockfd, InetAddress remote_address) :
+    m_sock(sockfd),
+    m_remote_address(remote_address)
+{ }
+
+void TCPClient::connect(const std::string& hostname, int port)
+{
+    m_hostname = hostname;
+    m_port = port;
+    reconnect();
+}
+
+ssize_t TCPClient::recv(void *buffer, size_t length, int flags, int timeout_ms)
+{
+    try {
+        ssize_t ret = m_sock.recv(buffer, length, flags, timeout_ms);
+
+        if (ret == 0) {
+            m_sock.close();
+
+            TCPSocket newsock;
+            m_sock = std::move(newsock);
+            reconnect();
+        }
+
+        return ret;
+    }
+    catch (const TCPSocket::Interrupted&) {
+        return -1;
+    }
+    catch (const TCPSocket::Timeout&) {
+        return 0;
+    }
+
+    return 0;
+}
+
+void TCPClient::reconnect()
+{
+    int flags = fcntl(m_sock.m_sock, F_GETFL);
+    if (fcntl(m_sock.m_sock, F_SETFL, flags | O_NONBLOCK) == -1) {
+        std::string errstr(strerror(errno));
+        throw std::runtime_error("TCP: Could not set O_NONBLOCK: " + errstr);
+    }
+
+    m_sock.connect(m_hostname, m_port);
+}
+
+TCPConnection::TCPConnection(TCPSocket&& sock) :
+            queue(),
+            m_running(true),
+            m_sender_thread(),
+            m_sock(move(sock))
+{
+#if MISSING_OWN_ADDR
+    auto own_addr = m_sock.getOwnAddress();
+    auto addr = m_sock.getRemoteAddress();
+    etiLog.level(debug) << "New TCP Connection on port " <<
+        own_addr.getPort() << " from " <<
+        addr.getHostAddress() << ":" << addr.getPort();
+#endif
+    m_sender_thread = std::thread(&TCPConnection::process, this);
+}
+
+TCPConnection::~TCPConnection()
+{
+    m_running = false;
+    vector<uint8_t> termination_marker;
+    queue.push(termination_marker);
+    m_sender_thread.join();
+}
+
+void TCPConnection::process()
+{
+    while (m_running) {
+        vector<uint8_t> data;
+        queue.wait_and_pop(data);
+
+        if (data.empty()) {
+            // empty vector is the termination marker
+            m_running = false;
+            break;
+        }
+
+        try {
+            ssize_t remaining = data.size();
+            const uint8_t *buf = reinterpret_cast<const uint8_t*>(data.data());
+            const int timeout_ms = 10; // Less than one ETI frame
+
+            while (m_running and remaining > 0) {
+                const ssize_t sent = m_sock.send(buf, remaining, timeout_ms);
+                if (sent < 0 or sent > remaining) {
+                    throw std::logic_error("Invalid TCPSocket::send() return value");
+                }
+                remaining -= sent;
+                buf += sent;
+            }
+        }
+        catch (const std::runtime_error& e) {
+            m_running = false;
+        }
+    }
+
+#if MISSING_OWN_ADDR
+    auto own_addr = m_sock.getOwnAddress();
+    auto addr = m_sock.getRemoteAddress();
+    etiLog.level(debug) << "Dropping TCP Connection on port " <<
+        own_addr.getPort() << " from " <<
+        addr.getHostAddress() << ":" << addr.getPort();
+#endif
+}
+
+
+TCPDataDispatcher::TCPDataDispatcher(size_t max_queue_size) :
+    m_max_queue_size(max_queue_size)
+{
+}
+
+TCPDataDispatcher::~TCPDataDispatcher()
+{
+    m_running = false;
+    m_connections.clear();
+    m_listener_socket.close();
+    if (m_listener_thread.joinable()) {
+        m_listener_thread.join();
+    }
+}
+
+void TCPDataDispatcher::start(int port, const string& address)
+{
+    m_listener_socket.listen(port, address);
+
+    m_running = true;
+    m_listener_thread = std::thread(&TCPDataDispatcher::process, this);
+}
+
+void TCPDataDispatcher::write(const vector<uint8_t>& data)
+{
+    if (not m_running) {
+        throw runtime_error(m_exception_data);
+    }
+
+    for (auto& connection : m_connections) {
+        connection.queue.push(data);
+    }
+
+    m_connections.remove_if(
+            [&](const TCPConnection& conn){ return conn.queue.size() > m_max_queue_size; });
+}
+
+void TCPDataDispatcher::process()
+{
+    try {
+        const int timeout_ms = 1000;
+
+        while (m_running) {
+            // Add a new TCPConnection to the list, constructing it from the client socket
+            auto sock = m_listener_socket.accept(timeout_ms);
+            if (sock.valid()) {
+                m_connections.emplace(m_connections.begin(), move(sock));
+            }
+        }
+    }
+    catch (const std::runtime_error& e) {
+        m_exception_data = string("TCPDataDispatcher error: ") + e.what();
+        m_running = false;
+    }
+}
+
+TCPReceiveServer::TCPReceiveServer(size_t blocksize) :
+    m_blocksize(blocksize)
+{
+}
+
+void TCPReceiveServer::start(int listen_port, const std::string& address)
+{
+    m_listener_socket.listen(listen_port, address);
+
+    m_running = true;
+    m_listener_thread = std::thread(&TCPReceiveServer::process, this);
+}
+
+TCPReceiveServer::~TCPReceiveServer()
+{
+    m_running = false;
+    if (m_listener_thread.joinable()) {
+        m_listener_thread.join();
+    }
+}
+
+vector<uint8_t> TCPReceiveServer::receive()
+{
+    vector<uint8_t> buffer;
+    m_queue.try_pop(buffer);
+
+    // we can ignore try_pop()'s return value, because
+    // if it is unsuccessful the buffer is not touched.
+    return buffer;
+}
+
+void TCPReceiveServer::process()
+{
+    constexpr int timeout_ms = 1000;
+    constexpr int disconnect_timeout_ms = 10000;
+    constexpr int max_num_timeouts = disconnect_timeout_ms / timeout_ms;
+
+    while (m_running) {
+        auto sock = m_listener_socket.accept(timeout_ms);
+
+        int num_timeouts = 0;
+
+        while (m_running and sock.valid()) {
+            try {
+                vector<uint8_t> buf(m_blocksize);
+                ssize_t r = sock.recv(buf.data(), buf.size(), 0, timeout_ms);
+                if (r < 0) {
+                    throw logic_error("Invalid recv return value");
+                }
+                else {
+                    buf.resize(r);
+                    m_queue.push(move(buf));
+                }
+            }
+            catch (const TCPSocket::Interrupted&) {
+                break;
+            }
+            catch (const TCPSocket::Timeout&) {
+                num_timeouts++;
+            }
+
+            if (num_timeouts > max_num_timeouts) {
+                sock.close();
+            }
+        }
+    }
+}
+
+}
diff --git a/lib/Socket.h b/lib/Socket.h
new file mode 100644
index 0000000..8bb7fe1
--- /dev/null
+++ b/lib/Socket.h
@@ -0,0 +1,294 @@
+/*
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Her Majesty the
+   Queen in Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2019
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://www.opendigitalradio.org
+   */
+/*
+   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 <https://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#ifdef HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "ThreadsafeQueue.h"
+#include <cstdlib>
+#include <iostream>
+#include <vector>
+#include <atomic>
+#include <thread>
+#include <list>
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <pthread.h>
+#define SOCKET           int
+#define INVALID_SOCKET   -1
+#define SOCKET_ERROR     -1
+
+
+namespace Socket {
+
+struct InetAddress {
+    struct sockaddr_storage addr;
+
+    struct sockaddr *as_sockaddr() { return reinterpret_cast<sockaddr*>(&addr); };
+
+    void resolveUdpDestination(const std::string& destination, int port);
+};
+
+/** This class represents a UDP packet.
+ *
+ *  A UDP packet contains a payload (sequence of bytes) and an address. For
+ *  outgoing packets, the address is the destination address. For incoming
+ *  packets, the address tells the user from what source the packet arrived from.
+ */
+class UDPPacket
+{
+    public:
+        UDPPacket();
+        UDPPacket(size_t initSize);
+
+        std::vector<uint8_t> buffer;
+        InetAddress address;
+};
+
+/**
+ *  This class represents a socket for sending and receiving UDP packets.
+ *
+ *  A UDP socket is the sending or receiving point for a packet delivery service.
+ *  Each packet sent or received on a datagram socket is individually
+ *  addressed and routed. Multiple packets sent from one machine to another may
+ *  be routed differently, and may arrive in any order.
+ */
+class UDPSocket
+{
+    public:
+        /** Create a new socket that will not be bound to any port. To be used
+         * for data output.
+         */
+        UDPSocket();
+        /** Create a new socket.
+         *  @param port The port number on which the socket will be bound
+         */
+        UDPSocket(int port);
+        /** Create a new socket.
+         *  @param port The port number on which the socket will be bound
+         *  @param name The IP address on which the socket will be bound.
+         *              It is used to bind the socket on a specific interface if
+         *              the computer have many NICs.
+         */
+        UDPSocket(int port, const std::string& name);
+        ~UDPSocket();
+        UDPSocket(const UDPSocket& other) = delete;
+        const UDPSocket& operator=(const UDPSocket& other) = delete;
+
+        /** Close the already open socket, and create a new one. Throws a runtime_error on error.  */
+        void reinit(int port);
+        void reinit(int port, const std::string& name);
+
+        void close(void);
+        void send(UDPPacket& packet);
+        void send(const std::vector<uint8_t>& data, InetAddress destination);
+        UDPPacket receive(size_t max_size);
+        void joinGroup(const char* groupname, const char* if_addr = nullptr);
+        void setMulticastSource(const char* source_addr);
+        void setMulticastTTL(int ttl);
+
+        /** Set blocking mode. By default, the socket is blocking.
+         * throws a runtime_error on error.
+         */
+        void setBlocking(bool block);
+
+    protected:
+        SOCKET m_sock;
+};
+
+/* Threaded UDP receiver */
+class UDPReceiver {
+    public:
+        UDPReceiver();
+        ~UDPReceiver();
+        UDPReceiver(const UDPReceiver&) = delete;
+        UDPReceiver operator=(const UDPReceiver&) = delete;
+
+        // Start the receiver in a separate thread
+        void start(int port, const std::string& bindto, const std::string& mcastaddr, size_t max_packets_queued);
+
+        // Get the data contained in a UDP packet, blocks if none available
+        // In case of error, throws a runtime_error
+        std::vector<uint8_t> get_packet_buffer(void);
+
+    private:
+        void m_run(void);
+
+        int m_port = 0;
+        std::string m_bindto;
+        std::string m_mcastaddr;
+        size_t m_max_packets_queued = 1;
+        std::thread m_thread;
+        std::atomic<bool> m_stop = ATOMIC_VAR_INIT(false);
+        ThreadsafeQueue<UDPPacket> m_packets;
+        UDPSocket m_sock;
+};
+
+class TCPSocket {
+    public:
+        TCPSocket();
+        ~TCPSocket();
+        TCPSocket(const TCPSocket& other) = delete;
+        TCPSocket& operator=(const TCPSocket& other) = delete;
+        TCPSocket(TCPSocket&& other);
+        TCPSocket& operator=(TCPSocket&& other);
+
+        bool valid(void) const;
+        void connect(const std::string& hostname, int port);
+        void listen(int port, const std::string& name);
+        void close(void);
+
+        /* throws a runtime_error on failure, an invalid socket on timeout */
+        TCPSocket accept(int timeout_ms);
+
+        /* returns -1 on error, doesn't work on nonblocking sockets */
+        ssize_t sendall(const void *buffer, size_t buflen);
+
+        /** Send data over the TCP connection.
+         *  @param data The buffer that will be sent.
+         *  @param size Number of bytes to send.
+         *  @param timeout_ms number of milliseconds before timeout, or 0 for infinite timeout
+         *  return number of bytes sent, 0 on timeout, or throws runtime_error.
+         */
+        ssize_t send(const void* data, size_t size, int timeout_ms=0);
+
+        /* Returns number of bytes read, 0 on disconnect. Throws a
+         * runtime_error on error */
+        ssize_t recv(void *buffer, size_t length, int flags);
+
+        class Timeout {};
+        class Interrupted {};
+        /* Returns number of bytes read, 0 on disconnect or refused connection.
+         * Throws a Timeout on timeout, Interrupted on EINTR, a runtime_error
+         * on error
+         */
+        ssize_t recv(void *buffer, size_t length, int flags, int timeout_ms);
+
+    private:
+        explicit TCPSocket(int sockfd);
+        explicit TCPSocket(int sockfd, InetAddress remote_address);
+        SOCKET m_sock = -1;
+
+        InetAddress m_remote_address;
+
+        friend class TCPClient;
+};
+
+/* Implements a TCP receiver that auto-reconnects on errors */
+class TCPClient {
+    public:
+        void connect(const std::string& hostname, int port);
+
+        /* Returns numer of bytes read, 0 on auto-reconnect, -1
+         * on interruption.
+         * Throws a runtime_error on error */
+        ssize_t recv(void *buffer, size_t length, int flags, int timeout_ms);
+
+    private:
+        void reconnect(void);
+        TCPSocket m_sock;
+        std::string m_hostname;
+        int m_port;
+};
+
+/* Helper class for TCPDataDispatcher, contains a queue of pending data and
+ * a sender thread. */
+class TCPConnection
+{
+    public:
+        TCPConnection(TCPSocket&& sock);
+        TCPConnection(const TCPConnection&) = delete;
+        TCPConnection& operator=(const TCPConnection&) = delete;
+        ~TCPConnection();
+
+        ThreadsafeQueue<std::vector<uint8_t> > queue;
+
+    private:
+        std::atomic<bool> m_running;
+        std::thread m_sender_thread;
+        TCPSocket m_sock;
+
+        void process(void);
+};
+
+/* Send a TCP stream to several destinations, and automatically disconnect destinations
+ * whose buffer overflows.
+ */
+class TCPDataDispatcher
+{
+    public:
+        TCPDataDispatcher(size_t max_queue_size);
+        ~TCPDataDispatcher();
+        TCPDataDispatcher(const TCPDataDispatcher&) = delete;
+        TCPDataDispatcher& operator=(const TCPDataDispatcher&) = delete;
+
+        void start(int port, const std::string& address);
+        void write(const std::vector<uint8_t>& data);
+
+    private:
+        void process();
+
+        size_t m_max_queue_size;
+
+        std::atomic<bool> m_running;
+        std::string m_exception_data;
+        std::thread m_listener_thread;
+        TCPSocket m_listener_socket;
+        std::list<TCPConnection> m_connections;
+};
+
+/* A TCP Server to receive data, which abstracts the handling of connects and disconnects.
+ */
+class TCPReceiveServer {
+    public:
+        TCPReceiveServer(size_t blocksize);
+        ~TCPReceiveServer();
+        TCPReceiveServer(const TCPReceiveServer&) = delete;
+        TCPReceiveServer& operator=(const TCPReceiveServer&) = delete;
+
+        void start(int listen_port, const std::string& address);
+
+        // Return a vector that contains up to blocksize bytes of data, or
+        // and empty vector if no data is available.
+        std::vector<uint8_t> receive();
+
+    private:
+        void process();
+
+        size_t m_blocksize = 0;
+        ThreadsafeQueue<std::vector<uint8_t> > m_queue;
+        std::atomic<bool> m_running;
+        std::string m_exception_data;
+        std::thread m_listener_thread;
+        TCPSocket m_listener_socket;
+};
+
+}
diff --git a/lib/ThreadsafeQueue.h b/lib/ThreadsafeQueue.h
new file mode 100644
index 0000000..62f4c96
--- /dev/null
+++ b/lib/ThreadsafeQueue.h
@@ -0,0 +1,176 @@
+/*
+   Copyright (C) 2007, 2008, 2009, 2010, 2011 Her Majesty the Queen in
+   Right of Canada (Communications Research Center Canada)
+
+   Copyright (C) 2018
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+   An implementation for a threadsafe queue, depends on C++11
+
+   When creating a ThreadsafeQueue, one can specify the minimal number
+   of elements it must contain before it is possible to take one
+   element out.
+ */
+/*
+   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 <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <mutex>
+#include <condition_variable>
+#include <queue>
+#include <utility>
+
+/* This queue is meant to be used by two threads. One producer
+ * that pushes elements into the queue, and one consumer that
+ * retrieves the elements.
+ *
+ * The queue can make the consumer block until an element
+ * is available, or a wakeup requested.
+ */
+
+/* Class thrown by blocking pop to tell the consumer
+ * that there's a wakeup requested. */
+class ThreadsafeQueueWakeup {};
+
+template<typename T>
+class ThreadsafeQueue
+{
+public:
+    /* Push one element into the queue, and notify another thread that
+     * might be waiting.
+     *
+     * returns the new queue size.
+     */
+    size_t push(T const& val)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        the_queue.push(val);
+        size_t queue_size = the_queue.size();
+        lock.unlock();
+
+        the_rx_notification.notify_one();
+
+        return queue_size;
+    }
+
+    size_t push(T&& val)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        the_queue.emplace(std::move(val));
+        size_t queue_size = the_queue.size();
+        lock.unlock();
+
+        the_rx_notification.notify_one();
+
+        return queue_size;
+    }
+
+    /* Push one element into the queue, but wait until the
+     * queue size goes below the threshold.
+     *
+     * Notify waiting thread.
+     *
+     * returns the new queue size.
+     */
+    size_t push_wait_if_full(T const& val, size_t threshold)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        while (the_queue.size() >= threshold) {
+            the_tx_notification.wait(lock);
+        }
+        the_queue.push(val);
+        size_t queue_size = the_queue.size();
+        lock.unlock();
+
+        the_rx_notification.notify_one();
+
+        return queue_size;
+    }
+
+    /* Trigger a wakeup event on a blocking consumer, which
+     * will receive a ThreadsafeQueueWakeup exception.
+     */
+    void trigger_wakeup(void)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        wakeup_requested = true;
+        lock.unlock();
+        the_rx_notification.notify_one();
+    }
+
+    /* Send a notification for the receiver thread */
+    void notify(void)
+    {
+        the_rx_notification.notify_one();
+    }
+
+    bool empty() const
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        return the_queue.empty();
+    }
+
+    size_t size() const
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        return the_queue.size();
+    }
+
+    bool try_pop(T& popped_value)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        if (the_queue.empty()) {
+            return false;
+        }
+
+        popped_value = the_queue.front();
+        the_queue.pop();
+
+        lock.unlock();
+        the_tx_notification.notify_one();
+
+        return true;
+    }
+
+    void wait_and_pop(T& popped_value, size_t prebuffering = 1)
+    {
+        std::unique_lock<std::mutex> lock(the_mutex);
+        while (the_queue.size() < prebuffering and
+                not wakeup_requested) {
+            the_rx_notification.wait(lock);
+        }
+
+        if (wakeup_requested) {
+            wakeup_requested = false;
+            throw ThreadsafeQueueWakeup();
+        }
+        else {
+            std::swap(popped_value, the_queue.front());
+            the_queue.pop();
+
+            lock.unlock();
+            the_tx_notification.notify_one();
+        }
+    }
+
+private:
+    std::queue<T> the_queue;
+    mutable std::mutex the_mutex;
+    std::condition_variable the_rx_notification;
+    std::condition_variable the_tx_notification;
+    bool wakeup_requested = false;
+};
+