C rewrite: phase out std::string

TunDevice.cpp

@@ -5,21 +5,22 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
-#include <cstdlib>
-#include <cstring>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
 
 #include "TunDevice.hpp"
 
 static const size_t TUN_MTU = 1500;  // TODO determine this cleanly
 
-TunDevice::TunDevice(const std::string& dev)
+TunDevice::TunDevice(const char* dev)
 {
     struct ifreq ifr;
     int fd;
 
     if( (fd = open("/dev/net/tun", O_RDWR)) < 0 ) {
-        throw TunDevice::InitializationError(
-                "Cannot open /dev/net/tun", errno, true);
+        perror("Tun device: cannot open /dev/net/tun: ");
+        exit(1);
     }
 
     memset(&ifr, 0, sizeof(ifr));
@@ -30,16 +31,18 @@ TunDevice::TunDevice(const std::string& dev)
      *        IFF_NO_PI - Do not provide packet information
      */
     ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
-    if(!dev.empty()) {
-        if(dev.size() >= IFNAMSIZ - 2)
-            throw TunDevice::InitializationError("Device name is too long.");
-        strncpy(ifr.ifr_name, dev.c_str(), IFNAMSIZ-1);
+    if(dev != nullptr) {
+        if(strlen(dev) >= IFNAMSIZ - 2) {
+            fprintf(stderr, "Tun device: device name is too long.\n");
+            exit(1);
+        }
+        strncpy(ifr.ifr_name, dev, IFNAMSIZ-1);
     }
 
     if(ioctl(fd, TUNSETIFF, (void *) &ifr) < 0){
         close(fd);
-        throw TunDevice::InitializationError(
-                "Tunnel interface failed [TUNSETIFF]", errno, true);
+        perror("Tun device: tunnel interface failed [TUNSETIFF]: ");
+        exit(1);
     }
     _dev_name = ifr.ifr_name;
     _fd = fd;
@@ -50,16 +53,16 @@ TunDevice::TunDevice(const std::string& dev)
     if(ioctl(sockfd, SIOCGIFFLAGS, (void*) &ifr) < 0) {
         close(fd);
         close(sockfd);
-        throw TunDevice::InitializationError(
-                "Could not get tunnel interface flags", errno, true);
+        perror("Tun device: could not get tunnel interface flags: ");
+        exit(1);
     }
     ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
 
     if(ioctl(sockfd, SIOCSIFFLAGS, (void*) &ifr) < 0) {
         close(fd);
         close(sockfd);
-        throw TunDevice::InitializationError(
-                "Could not bring tunnel interface up", errno, true);
+        perror("Tun device: could not bring tunnel interface up: ");
+        exit(1);
     }
     close(sockfd);
 
@@ -77,7 +80,7 @@ uint16_t TunDevice::get_mtu() const {
 
     struct ifreq ifr;
     ifr.ifr_addr.sa_family = AF_INET6;
-    strncpy(ifr.ifr_name, _dev_name.c_str(), sizeof(ifr.ifr_name)-1);
+    strncpy(ifr.ifr_name, _dev_name, sizeof(ifr.ifr_name)-1);
     if (ioctl(sockfd, SIOCGIFMTU, (caddr_t)&ifr) < 0)
         return 0;
     close(sockfd);
@@ -89,7 +92,7 @@ bool TunDevice::set_mtu(uint16_t mtu) {
 
     struct ifreq ifr;
     ifr.ifr_addr.sa_family = AF_INET6;
-    strncpy(ifr.ifr_name, _dev_name.c_str(), sizeof(ifr.ifr_name)-1);
+    strncpy(ifr.ifr_name, _dev_name, sizeof(ifr.ifr_name)-1);
     ifr.ifr_mtu = mtu;
     if (ioctl(sockfd, SIOCSIFMTU, (caddr_t)&ifr) < 0)
         return false;
@@ -102,8 +105,8 @@ size_t TunDevice::poll_packet(char* read_buffer, size_t buf_size, int timeout) {
     if(poll_rc < 0) {
         if(errno == EINTR) // Interrupt.
             return 0;
-        throw TunDevice::NetError(
-                "Error polling from interface", errno, true);
+        perror("Tun device: error polling from interface: ");
+        exit(1);
     }
     else if(poll_rc == 0 || (_poll_fd.revents & POLLIN) == 0) {
         // Nothing to read
@@ -116,8 +119,8 @@ size_t TunDevice::poll_packet(char* read_buffer, size_t buf_size, int timeout) {
 size_t TunDevice::read(char* read_buffer, size_t buf_size) {
     int nread = ::read(_fd, read_buffer, buf_size);
     if(nread < 0) {
-        throw TunDevice::NetError(
-                "Error reading from interface", errno, true);
+        perror("Tun device: error reading from interface: ");
+        exit(1);
     }
     _last_read_size = nread;
     return _last_read_size;
@@ -126,8 +129,8 @@ size_t TunDevice::read(char* read_buffer, size_t buf_size) {
 size_t TunDevice::write(const char* data, size_t len) {
     int nwritten = ::write(_fd, data, len);
     if(nwritten < 0) {
-        throw TunDevice::NetError(
-                "Error writing to interface: ", errno, true);
+        perror("Tun device: error writing to interface: ");
+        exit(1);
     }
     return nwritten;
 }

TunDevice.hpp

@@ -1,32 +1,14 @@
 #pragma once
 
-#include <string>
 #include <poll.h>
 #include "util.hpp"
 
 class TunDevice {
     public:
-        class InitializationError : public MsgException {
-            public:
-                InitializationError(
-                        const std::string& msg,
-                        int code=0,
-                        bool is_perror=false)
-                    : MsgException(msg, code, is_perror) {}
-        };
-        class NetError : public MsgException {
-            public:
-                NetError(
-                        const std::string& msg,
-                        int code=0,
-                        bool is_perror=false)
-                    : MsgException(msg, code, is_perror) {}
-        };
-
-        TunDevice(const std::string& dev);
+        TunDevice(const char* dev);
         ~TunDevice();
 
-        const std::string& get_dev_name() const { return _dev_name; }
+        const char* get_dev_name() const { return _dev_name; }
         int get_fd() const { return _fd; }
 
         /** Get the interface's MTU */
@@ -48,7 +30,7 @@ class TunDevice {
 
     private:
         int _fd;
-        std::string _dev_name;
+        char*_dev_name;
         struct pollfd _poll_fd;
         size_t _last_read_size;
 };

UdpVpn.cpp

@@ -1,6 +1,5 @@
 #include "UdpVpn.hpp"
 
-#include <chrono>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -10,6 +9,7 @@
 #include <poll.h>
 #include <errno.h>
 #include <math.h>
+#include <stdio.h>
 
 #include "ip_header.hpp"
 
@@ -19,12 +19,16 @@ UdpVpn::UdpVpn()
     : _stopped(false), _dump_requested(false), _vpn_mtu(VPN_MTU),
     _tun_dev("cvpn%d"), _peer(nullptr)
 {
-    _last_tick = _last_control_sent =
-        std::chrono::steady_clock::now() - std::chrono::seconds(1);
+    clock_gettime(CLOCK_MONOTONIC, &_last_tick);
+    _last_tick.tv_sec--;
+    memcpy(&_last_control_sent, &_last_tick, sizeof(struct timespec));
+
     _tun_dev.set_mtu(VpnPacket::get_tunnelled_mtu(_vpn_mtu));
     _socket = socket(AF_INET6, SOCK_DGRAM, 0);
-    if(_socket < 0)
-        throw UdpVpn::InitializationError("Cannot create socket", errno, true);
+    if(_socket < 0) {
+        perror("UdpVpn: cannot create socket: ");
+        exit(1);
+    }
 }
 
 UdpVpn::~UdpVpn() {
@@ -57,23 +61,19 @@ void UdpVpn::run() {
         if(rc < 0) {
             if(errno == EINTR)  // Interrupt.
                 continue;
-            throw UdpVpn::NetError(
-                    "Error polling from interface", errno, true);
+            perror("UdpVpn: error polling from interface: ");
+            exit(1);
         }
 
         // ## Check periodic actions
         if(_peer) {
-            if(std::chrono::steady_clock::now() - _last_control_sent
-                > std::chrono::milliseconds(100))
-            {
+            if(timespec_us_ellapsed(_last_control_sent) > 1000*1000) {
                 if(_peer->send_control_packet())
-                    _last_control_sent = std::chrono::steady_clock::now();
+                    clock_gettime(CLOCK_MONOTONIC, &_last_control_sent);
             }
         }
-        if(std::chrono::steady_clock::now() - _last_tick
-                > std::chrono::milliseconds(50))
-        {
-            _last_tick = std::chrono::steady_clock::now();
+        if(timespec_us_ellapsed(_last_tick) > 50*1000) {
+            clock_gettime(CLOCK_MONOTONIC, &_last_tick);
             if(_peer)
                 _peer->tick();
         }
@@ -127,8 +127,10 @@ size_t UdpVpn::read_from_udp(char* buffer, size_t len,
     nread = recvfrom(_socket, buffer, len, 0,
             (struct sockaddr*) &peer_addr, &peer_addr_len);
 
-    if(nread < 0)
-        throw UdpVpn::NetError("Cannot receive datagram", errno, true);
+    if(nread < 0) {
+        perror("UdpVpn: cannot receive datagram: ");
+        exit(1);
+    }
     if(nread == 0)
         return 0;
 
@@ -173,7 +175,7 @@ void UdpVpn::receive_from_tun() {
         debugf("Dropping packet: no peer yet.\n");
         return;
     }
-    packet.set_peer(_peer.get());
+    packet.set_peer(_peer);
 
     kdebugf("Transmitting %s -> %s, size %d\n",
             format_address(packet.get_ipv6_header().source.s6_addr),
@@ -192,7 +194,7 @@ void UdpVpn::receive_from_udp() {
         return;
 
     // If we don't have a peer yet -- we're just setting the peer to nullptr.
-    packet.set_peer(_peer.get());
+    packet.set_peer(_peer);
 
     if(packet.is_control()) {
         VpnControlPacket ctrl_packet(std::move(packet));
@@ -257,12 +259,10 @@ void UdpVpn::dump_state() const {
             round(_peer->get_loss_logger().get_loss_rate() * 100));
     printf("Packet loss rate (outbound): %.0lf%%\n",
             round(_peer->get_loss_reports().loss_rate() * 100));
-    printf("RTT: %.02lf ms avg, %.02lf ms last [last updated: %lu ms ago]\n",
+    printf("RTT: %.02lf ms avg, %.02lf ms last [last updated: %u ms ago]\n",
             (double)_peer->get_rtt().avg_rtt() / 1e3,
             (double)_peer->get_rtt().cur_rtt() / 1e3,
-            std::chrono::duration_cast<std::chrono::milliseconds>(
-                std::chrono::steady_clock::now()
-                - _peer->get_rtt().get_last_update()).count()
+            timespec_us_ellapsed(_peer->get_rtt().get_last_update()) / 1000
           );
     printf("Total bytes transmitted: %s\n",
             human_readable_unit(_peer->get_tot_bytes_sent(), "B"));

UdpVpn.hpp

@@ -2,6 +2,7 @@
 
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <time.h>
 
 #include "util.hpp"
 #include "TunDevice.hpp"
@@ -12,23 +13,6 @@
 
 class UdpVpn {
     public:
-        class InitializationError : public MsgException {
-            public:
-                InitializationError(
-                        const std::string& msg,
-                        int code=0,
-                        bool is_perror=false)
-                    : MsgException(msg, code, is_perror) {}
-        };
-        class NetError : public MsgException {
-            public:
-                NetError(
-                        const std::string& msg,
-                        int code=0,
-                        bool is_perror=false)
-                    : MsgException(msg, code, is_perror) {}
-        };
-
         UdpVpn();
         virtual ~UdpVpn();
 
@@ -71,9 +55,9 @@ class UdpVpn {
         size_t _vpn_mtu;
 
         TunDevice _tun_dev;
-        std::unique_ptr<VpnPeer> _peer;
+        VpnPeer* _peer;
 
-        std::chrono::steady_clock::time_point
+        struct timespec
             _last_control_sent, /**< A control is offered to be sent approx.
                                   every 100ms */
             _last_tick /**< A tick occurs approx. each 50ms */;

UdpVpnClient.cpp

@@ -1,10 +1,14 @@
-#include <cstring>
+#include <string.h>
 
 #include "UdpVpnClient.hpp"
 #include "ip_header.hpp"
 
 UdpVpnClient::UdpVpnClient(const struct sockaddr_in6& server) : UdpVpn() {
-    _peer = std::make_unique<VpnPeer>(this, server, in6addr_any);
+    _peer = new VpnPeer(this, server, in6addr_any);
+}
+
+UdpVpnClient::~UdpVpnClient() {
+    delete _peer;
 }
 
 void UdpVpnClient::acquire_peer(

UdpVpnClient.hpp

@@ -5,6 +5,7 @@
 class UdpVpnClient: public UdpVpn {
     public:
         UdpVpnClient(const struct sockaddr_in6& server);
+        ~UdpVpnClient();
 
     protected:
         virtual void acquire_peer(

UdpVpnServer.cpp

@@ -1,4 +1,5 @@
-#include <cstring>
+#include <string.h>
+#include <stdio.h>
 
 #include "UdpVpnServer.hpp"
 #include "ip_header.hpp"
@@ -15,6 +16,11 @@ UdpVpnServer::UdpVpnServer(const struct in6_addr& bind_addr6, in_port_t port)
     bind(bind_addr6, port);
 }
 
+UdpVpnServer::~UdpVpnServer() {
+    if(_peer != nullptr)
+        delete _peer;
+}
+
 void UdpVpnServer::acquire_peer(
         VpnDataPacket& packet,
         const sockaddr_in6& peer_ext_addr)
@@ -26,9 +32,9 @@ void UdpVpnServer::acquire_peer(
     if(!packet.parse_as_ipv6())
         return;
     const in6_addr& peer_inner_addr = packet.get_ipv6_header().source;
-    _peer = std::make_unique<VpnPeer>(this, peer_ext_addr, peer_inner_addr);
+    _peer = new VpnPeer(this, peer_ext_addr, peer_inner_addr);
 
-    packet.set_peer(_peer.get());
+    packet.set_peer(_peer);
 
     debugf("Got new peer %s:%d -- %s\n",
             format_address(peer_ext_addr.sin6_addr.s6_addr),
@@ -46,7 +52,8 @@ void UdpVpnServer::bind(const struct in6_addr& bind_addr6, in_port_t port) {
     rc = ::bind(
             _socket, (const struct sockaddr*)&_bind_addr, sizeof(_bind_addr));
     if(rc < 0) {
-        throw UdpVpn::InitializationError("Cannot bind socket", errno, true);
+        perror("UdpVpn: cannot bind socket: ");
+        exit(1);
     }
 
     debugf("> Listening on port %d\n", port);

UdpVpnServer.hpp

@@ -1,14 +1,13 @@
 #pragma once
 
-#include <unordered_map>
-#include <memory>
-
 #include "UdpVpn.hpp"
 
 class UdpVpnServer: public UdpVpn {
     public:
         UdpVpnServer(in_port_t port);
         UdpVpnServer(const struct in6_addr& bind_addr6, in_port_t port);
+
+        ~UdpVpnServer();
     protected:
         virtual void acquire_peer(
                 VpnDataPacket& packet,

VpnPacket.cpp

@@ -1,8 +1,9 @@
 #include "VpnPacket.hpp"
 #include "VpnPeer.hpp"
 
-#include <chrono>
-#include <cstring>
+#include <string.h>
+#include <stdio.h>
+#include <utility>
 
 const size_t VpnPacket::VPN_HEADER_BYTES = 8;
 const size_t VpnControlPacket::TLV_HEADER_BYTES = 3;
@@ -20,10 +21,12 @@ VpnPacket::VpnPacket(size_t mtu, bool inbound)
     : _peer(nullptr), _inbound(inbound), _data_space(mtu-OUTER_HEADERS_BYTES),
       _data_size(VPN_HEADER_BYTES), _reception_timestamp(0)
 {
-    _data = std::unique_ptr<char[]>(new char[mtu - OUTER_HEADERS_BYTES]);
+    _data = (char*) malloc(sizeof(char) * (mtu - OUTER_HEADERS_BYTES));
 }
 
-VpnPacket::~VpnPacket() {}
+VpnPacket::~VpnPacket() {
+    free(_data);
+}
 
 VpnPacket::VpnPacket(VpnPacket&& move_from) :
     _peer(move_from._peer),
@@ -45,49 +48,43 @@ void VpnPacket::set_peer(VpnPeer* peer) {
 }
 
 uint32_t VpnPacket::get_seqno() const {
-    return ntohl(*(uint32_t*)(_data.get() + DATA_SEQNO_POS));
+    return ntohl(*(uint32_t*)(_data + DATA_SEQNO_POS));
 }
 
 uint32_t VpnPacket::get_sending_timestamp() const {
     return ntohl(
-            *(uint32_t*)(_data.get() + DATA_TIMESTAMP_POS) & 0x7fffffffUL
+            *(uint32_t*)(_data + DATA_TIMESTAMP_POS) & 0x7fffffffUL
             );
 }
 
 bool VpnPacket::is_control() const {
-    return *(unsigned char*)(_data.get() + DATA_CTRLBIT_POS) & 0x80;
+    return *(unsigned char*)(_data + DATA_CTRLBIT_POS) & 0x80;
 }
 
 void VpnPacket::set_control(bool is_control) {
     unsigned char* ctrl_field =
-        (unsigned char*) (_data.get() + DATA_CTRLBIT_POS);
+        (unsigned char*) (_data + DATA_CTRLBIT_POS);
     *ctrl_field &= 0x7f;
     if(is_control)
         *ctrl_field |= 0x80;
 }
 
 void VpnPacket::prepare_for_sending() {
-    uint32_t* ts_field = (uint32_t*) (_data.get() + DATA_TIMESTAMP_POS);
+    uint32_t* ts_field = (uint32_t*) (_data + DATA_TIMESTAMP_POS);
     *ts_field &= htonl(0x80000000UL);
-    *(uint32_t*)(_data.get() + DATA_SEQNO_POS) = htonl(next_seqno());
-    *ts_field |=
-        htonl(to_us_timestamp(
-                    std::chrono::time_point_cast<std::chrono::microseconds>(
-                        std::chrono::steady_clock::now()
-                        ).time_since_epoch().count())
-             );
+    *(uint32_t*)(_data + DATA_SEQNO_POS) = htonl(next_seqno());
+    *ts_field |= htonl(to_us_timestamp(current_us_timestamp()));
 }
 
 void VpnPacket::upon_reception() {
-    _reception_timestamp = to_us_timestamp(
-            std::chrono::time_point_cast<std::chrono::microseconds>(
-                std::chrono::steady_clock::now()
-                ).time_since_epoch().count());
+    _reception_timestamp = to_us_timestamp(current_us_timestamp());
 }
 
 uint32_t VpnPacket::next_seqno() {
-    if(!_peer)
-        throw PeerNotSet();
+    if(!_peer) {
+        fprintf(stderr, "ERROR: trying to get seqno without peer.\n");
+        return 0;
+    }
     return _peer->next_seqno();
 }
 

VpnPacket.hpp

@@ -2,8 +2,7 @@
 
 /** A packet to be transmitted or received over the VPN socket */
 
-#include <cstdlib>
-#include <memory>
+#include <stdlib.h>
 
 #include "ip_header.hpp"
 
@@ -50,7 +49,6 @@ class VpnPacketTLV;
 class VpnPacket {
     public:
         static const size_t VPN_HEADER_BYTES;
-        class PeerNotSet: public std::exception {};
 
         VpnPacket(size_t mtu, bool inbound);
         ~VpnPacket();
@@ -74,9 +72,9 @@ class VpnPacket {
 
         /// Get a pointer to the packet payload (const version)
         const char* get_payload() const {
-            return _data.get() + VPN_HEADER_BYTES; }
+            return _data + VPN_HEADER_BYTES; }
         /// Get a pointer to the packet payload
-        char* get_payload() { return _data.get() + VPN_HEADER_BYTES; }
+        char* get_payload() { return _data + VPN_HEADER_BYTES; }
         /// Get a pointer to the first free byte of the packet payload
         char* get_next_payload() { return get_payload() + get_payload_size(); }
         /// Get the space allocated for the packet payload
@@ -94,9 +92,9 @@ class VpnPacket {
             _data_size += payload_size_increment; }
 
         /// Get a pointer to the full packet data (const version)
-        const char* get_data() const { return _data.get(); }
+        const char* get_data() const { return _data; }
         /// Get a pointer to the full packet data
-        char* get_data() { return _data.get(); }
+        char* get_data() { return _data; }
         /// Get the space allocated for the packet
         size_t get_data_space() const { return _data_space; }
         /// Get the total current size of the packet
@@ -134,7 +132,7 @@ class VpnPacket {
         VpnPeer* _peer; // raw pointer: we do not own the peer in any way
         bool _inbound; ///< is the packet received or sent?
 
-        std::unique_ptr<char[]> _data;
+        char* _data;
         size_t _data_space, _data_size;
 
         uint32_t _reception_timestamp;

VpnPeer.cpp

@@ -1,9 +1,9 @@
 #include "UdpVpn.hpp"
 #include "congestion_control.hpp"
 
-#include <cstdint>
-#include <cstring>
-#include <functional>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
 
 const double RTTLogger::EXP_AVG_FACTOR = 0.75;
 const unsigned int RTTLogger::BASE_UPDATE_DELAY = 1000; // ms
@@ -12,12 +12,18 @@ VpnPeer::VpnPeer(UdpVpn* vpn, const sockaddr_in6& ext_addr,
         const in6_addr& int_addr)
     : _vpn(vpn), _ext_addr(ext_addr), _int_addr(int_addr), _next_send_seqno(0),
     _tot_bytes_sent(0), _prev_tot_bytes_sent(0),
-    _congestion_controller(*this)
+    _congestion_controller(*this),
+    _next_control_packet(nullptr)
 {
-    _prev_tick_time = std::chrono::steady_clock::now();
+    clock_gettime(CLOCK_MONOTONIC, &_prev_tick_time);
     cycle_next_control();
 }
 
+VpnPeer::~VpnPeer() {
+    if(_next_control_packet != nullptr)
+        delete _next_control_packet;
+}
+
 void VpnPeer::make_loss_report() {
     VpnTlvLossReport report = VpnTlvLossReport::create(*_next_control_packet);
     report.set_report_seqno(_packet_loss.get_cur_seqno());
@@ -25,8 +31,9 @@ void VpnPeer::make_loss_report() {
 }
 
 void VpnPeer::cycle_next_control() {
-    _next_control_packet =
-        std::make_unique<VpnControlPacket>(_vpn->get_mtu(), false);
+    if(_next_control_packet != nullptr)
+        delete _next_control_packet;
+    _next_control_packet = new VpnControlPacket(_vpn->get_mtu(), false);
     _next_control_packet->set_peer(this);
 }
 
@@ -35,13 +42,13 @@ void VpnPeer::set_int_addr(const in6_addr& int_addr) {
 }
 
 void VpnPeer::tick() {
-    auto cur_time = std::chrono::steady_clock::now();
+    struct timespec cur_time;
+    clock_gettime(CLOCK_MONOTONIC, &cur_time);
 
     // Compute byte rate
     _outbound_byte_rate = /* byte per second */
         (double)(_tot_bytes_sent - _prev_tot_bytes_sent)
-        / (double)(std::chrono::duration_cast<std::chrono::microseconds>(
-                    cur_time - _prev_tick_time).count())
+        / timespec_us_diff(cur_time, _prev_tick_time)
         * 1e6;
 
     _prev_tot_bytes_sent = _tot_bytes_sent;
@@ -63,8 +70,10 @@ size_t VpnPeer::write(const char* data, size_t len) {
 
     nsent = sendto(_vpn->get_socket_fd(), data, len, MSG_CONFIRM,
             (const struct sockaddr*) &_ext_addr, sizeof(_ext_addr));
-    if(nsent < 0)
-        throw NetError("Could not send UDP packet", errno, true);
+    if(nsent < 0) {
+        perror("Could not send UDP packet: ");
+        exit(1);
+    }
 
     _tot_bytes_sent += nsent;
 
@@ -110,27 +119,32 @@ void PacketLossLogger::log_packet(uint32_t seqno) {
     if(diff == 1) {
         _cur_seqno++;
         maybe_start_window();
-        while(_received_ahead.test((_cur_seqno + 1) % PACKET_LOST_AFTER)) {
+        while(_received_ahead & (1 << (_cur_seqno + 1 % PACKET_LOST_AFTER))) {
             _cur_seqno++;
-            _received_ahead.reset(_cur_seqno % PACKET_LOST_AFTER);
+            _received_ahead &= ~(1 << (_cur_seqno + 1 % PACKET_LOST_AFTER));
             maybe_start_window();
         }
     } else if(LIKELY(diff > 1)) {
         if(diff < PACKET_LOST_AFTER)
-            _received_ahead.set(seqno % PACKET_LOST_AFTER);
+            _received_ahead |= (1 << (seqno % PACKET_LOST_AFTER));
         else if(diff < PACKET_LOSS_WINDOW) {
             // Packet too much forwards -- consider _cur_seqno lost
             if(_cur_seqno % PACKET_LOSS_WINDOW > seqno % PACKET_LOSS_WINDOW) {
                 // This loss crosses a window border
                 for(int offs=0; offs < PACKET_LOST_AFTER; ++offs) {
                     maybe_start_window(offs);
-                    if(!_received_ahead[(_cur_seqno + offs) % PACKET_LOST_AFTER])
+                    if((_received_ahead & (1 << ((_cur_seqno + offs) % PACKET_LOST_AFTER))) == 0)
                         _tot_losses++;
                 }
             } else {
-                _tot_losses += PACKET_LOST_AFTER - _received_ahead.count();
+                _tot_losses += PACKET_LOST_AFTER;
+                while(_received_ahead > 0) {
+                    if(_received_ahead & 1)
+                        _tot_losses--;
+                    _received_ahead >>= 1;
                 }
-            _received_ahead.reset();
+            }
+            _received_ahead = 0;
             _cur_seqno = seqno;
         } else
             reboot(); // This is a huge gap -- reboot
@@ -142,7 +156,7 @@ void PacketLossLogger::log_packet(uint32_t seqno) {
 }
 
 void PacketLossLogger::reboot() {
-    _received_ahead.reset();
+    _received_ahead = 0;
     // _tot_losses unchanged
 }
 
@@ -153,12 +167,9 @@ void PacketLossLogger::maybe_start_window(int offs) {
     }
 }
 
-RTTLogger::RTTLogger() :
-    _avg_rtt(0), _cur_rtt(0),
-    _last_update(std::chrono::steady_clock::time_point::min())
-{
-    _last_update =
-        std::chrono::steady_clock::now() - std::chrono::seconds(1);
+RTTLogger::RTTLogger() : _avg_rtt(0), _cur_rtt(0) {
+    clock_gettime(CLOCK_MONOTONIC, &_last_update);
+    _last_update.tv_sec--;
     // This avoids situations where both peers try to renew their RTT at the
     // same time.
     _update_delay = BASE_UPDATE_DELAY + rand() % 100 - 50;
@@ -177,12 +188,11 @@ void RTTLogger::log(const VpnTlvRTTA& rtt_answer) {
         _avg_rtt = (1 - EXP_AVG_FACTOR) * _avg_rtt
             + EXP_AVG_FACTOR * _cur_rtt;
 
-    _last_update = std::chrono::steady_clock::now();
+    clock_gettime(CLOCK_MONOTONIC, &_last_update);
 }
 
 bool RTTLogger::update_due(bool soon) const {
     unsigned int ms_since_last_update =
-        std::chrono::duration_cast<std::chrono::milliseconds>(
-                std::chrono::steady_clock::now() - _last_update).count();
+        timespec_us_ellapsed(_last_update) / 1000;
     return ms_since_last_update >= (soon ? _update_delay/2 : _update_delay);
 }

VpnPeer.hpp

@@ -3,8 +3,7 @@
 /** A peer of a bound (server) instance of UdpVpn */
 
 #include <netinet/in.h>
-#include <bitset>
-#include <chrono>
+#include <time.h>
 #include "util.hpp"
 #include "VpnPacket.hpp"
 #include "congestion_control.hpp"
@@ -22,7 +21,7 @@ class PacketLossLogger {
                 / (double)PACKET_LOSS_WINDOW;
         }
 
-        const std::bitset<PACKET_LOST_AFTER> get_received_ahead() const {
+        uint8_t get_received_ahead() const {
             return _received_ahead;
         }
 
@@ -35,7 +34,7 @@ class PacketLossLogger {
         /// roll loss window values if `_cur_seqno + offs` is a window start.
         void maybe_start_window(int offs=0);
 
-        std::bitset<PACKET_LOST_AFTER> _received_ahead;
+        uint8_t _received_ahead; // Warning: must have >= bits than PACKET_LOSS_AFTER
         uint32_t _cur_seqno;
         unsigned int _tot_losses;
         unsigned int _last_window_losses, _win_start_losses;
@@ -47,7 +46,7 @@ class RTTLogger {
         RTTLogger();
         uint32_t avg_rtt() const { return _avg_rtt; }
         uint32_t cur_rtt() const { return _cur_rtt; }
-        std::chrono::steady_clock::time_point get_last_update() const {
+        struct timespec get_last_update() const {
             return _last_update;
         }
 
@@ -64,20 +63,11 @@ class RTTLogger {
 
         unsigned int _update_delay; // in ms
         static const unsigned int BASE_UPDATE_DELAY; // in ms
-        std::chrono::steady_clock::time_point _last_update;
+        struct timespec _last_update;
 };
 
 class VpnPeer {
     public:
-        class NetError : public MsgException {
-            public:
-                NetError(
-                        const std::string& msg,
-                        int code=0,
-                        bool is_perror=false)
-                    : MsgException(msg, code, is_perror) {}
-        };
-
         /// Logs the loss reports sent by the remote peer
         struct LossReports {
             uint32_t prev_seqno, last_seqno;
@@ -92,6 +82,8 @@ class VpnPeer {
         VpnPeer(UdpVpn* vpn, const sockaddr_in6& ext_addr,
                 const in6_addr& int_addr);
 
+        ~VpnPeer();
+
         const sockaddr_in6& get_ext_addr() const { return _ext_addr; }
         const in6_addr& get_int_addr() const { return _int_addr; }
 
@@ -139,12 +131,12 @@ class VpnPeer {
         uint64_t _tot_bytes_sent, _prev_tot_bytes_sent;
         double _outbound_byte_rate;
 
-        std::chrono::steady_clock::time_point _prev_tick_time;
+        struct timespec _prev_tick_time;
 
         PacketLossLogger _packet_loss;
         LossReports _loss_reports;
         RTTLogger _rtt;
         CongestionController _congestion_controller;
 
-        std::unique_ptr<VpnControlPacket> _next_control_packet;
+        VpnControlPacket* _next_control_packet;
 };

congestion_control.cpp

@@ -1,5 +1,6 @@
 #include "congestion_control.hpp"
 #include "VpnPeer.hpp"
+#include "util.hpp"
 
 CongestionController::CongestionController(const VpnPeer& peer):
     _peer(peer)
@@ -7,8 +8,8 @@ CongestionController::CongestionController(const VpnPeer& peer):
     _last_seqno = _peer.get_loss_logger().get_cur_seqno();
     _loss_based.bandwidth = 3e5; // 300kBps seems a good value to start with
     _loss_based.prev_tot_sent = _peer.get_tot_bytes_sent();
-    _last_bucket_update = _loss_based.prev_time =
-        std::chrono::steady_clock::now();
+    clock_gettime(CLOCK_MONOTONIC, &_last_bucket_update);
+    clock_gettime(CLOCK_MONOTONIC, &_loss_based.prev_time);
     update_params();
 }
 
@@ -20,12 +21,14 @@ void CongestionController::update_lossbased() {
 
     double loss_rate = (double)delta_losses / (double)delta_seqno;
 
-    auto cur_time = std::chrono::steady_clock::now();
+    struct timespec cur_time;
+    clock_gettime(CLOCK_MONOTONIC, &cur_time);
+
     uint64_t cur_sent = _peer.get_tot_bytes_sent();
+
     double instant_bandwidth = /* byte per second */
         (double)(cur_sent - _loss_based.prev_tot_sent)
-        / (double)(std::chrono::duration_cast<std::chrono::microseconds>(
-                    cur_time - _loss_based.prev_time).count())
+        / (double)(timespec_us_diff(cur_time, _loss_based.prev_time))
         * 1e6;
 
     _loss_based.prev_time = cur_time;
@@ -44,5 +47,6 @@ void CongestionController::update_lossbased() {
 void CongestionController::update_params() {
     _bandwidth = _loss_based.bandwidth; // meant to integrate other controllers
     _bucket_max_level = _bandwidth * _peer.get_rtt().avg_rtt();
-    _bucket_level = std::min(_bucket_level, _bucket_max_level);
+    if(_bucket_level > _bucket_max_level)
+        _bucket_level = _bucket_max_level;
 }

congestion_control.hpp

@@ -1,6 +1,6 @@
 #pragma once
 #include <stdint.h>
-#include <chrono>
+#include <time.h>
 
 class VpnPeer;
 
@@ -9,7 +9,7 @@ class CongestionController {
         struct LossBased {
             uint64_t bandwidth; // bytes per second
             uint64_t prev_tot_sent; // tot bytes sent during last update
-            std::chrono::steady_clock::time_point prev_time; // last update time
+            struct timespec prev_time; // last update time
         };
 
         CongestionController(const VpnPeer& peer);
@@ -34,6 +34,6 @@ class CongestionController {
 
         uint64_t _bucket_level, ///< implements a leaky bucket
                  _bucket_max_level; // bandwidth * RTT
-        std::chrono::steady_clock::time_point _last_bucket_update;
+        struct timespec _last_bucket_update;
 };
 

ip_header.cpp

@@ -1,4 +1,4 @@
-#include <cstring>
+#include <string.h>
 
 #include "ip_header.hpp"
 #include "util.hpp"

main.cpp

@@ -1,5 +1,5 @@
-#include <cstdio>
-#include <cstdlib>
+#include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <signal.h>
@@ -100,7 +100,6 @@ int main(int argc, char** argv) {
     signal(SIGINT, stop_sig_handler);
     signal(SIGUSR1, dump_sig_handler);
 
-    try {
     if(program_options.listen && program_options.has_peer) {
         fprintf(stderr,
                 "ERROR: Cannot be a server and a client at the same time "
@@ -137,15 +136,5 @@ int main(int argc, char** argv) {
     delete vpn_instance;
 
     printf("Shutting down.\n");
-    } catch(const TunDevice::InitializationError& exn) {
-        fprintf(stderr, "TUN INIT ERROR: %s\n", exn.what());
-    } catch(const TunDevice::NetError& exn) {
-        fprintf(stderr, "TUN NET ERROR: %s\n", exn.what());
-    } catch(const UdpVpn::InitializationError& exn) {
-        fprintf(stderr, "VPN INIT ERROR: %s\n", exn.what());
-    } catch(const UdpVpn::NetError& exn) {
-        fprintf(stderr, "VPN NET ERROR: %s\n", exn.what());
-    }
-
     return 0;
 }

util.cpp

@@ -1,7 +1,8 @@
-#include <cstdio>
+#include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
 #include <arpa/inet.h>
+#include <time.h>
 
 #include "util.hpp"
 
@@ -53,40 +54,39 @@ human_readable_unit(double value, const char* unit) {
     return buf[cur_buf];
 }
 
-
-namespace std {
-size_t hash<in6_addr>::operator() (const in6_addr& addr) const {
-    size_t out_hash = 0;
-    for(int i=0; i < 4; ++i) {
-        uint32_t value;
-        memcpy((unsigned char*)(&value),
-               addr.s6_addr + 4*i,
-               4);
-        out_hash ^= (std::hash<uint32_t>{}(value) << 1);
-    }
-    return out_hash;
-}
-
-bool equal_to<in6_addr>::operator()(
-        const in6_addr& lhs, const in6_addr& rhs) const
+void
+timespec_diff(const struct timespec t1, const struct timespec t2,
+        struct timespec* result)
 {
-    return memcmp(lhs.s6_addr, rhs.s6_addr, sizeof(lhs.s6_addr)) == 0;
+    result->tv_nsec = t1.tv_nsec - t2.tv_nsec;
+    result->tv_sec = t1.tv_sec - t2.tv_sec;
+    if(result->tv_nsec < 0) {
+        result->tv_nsec += 1000*1000*1000;
+        result->tv_sec--;
     }
 }
 
-MsgException::MsgException(const std::string& msg, int code, bool is_perror)
-    : _msg(msg), _code(code)
-{
-    _what = _msg;
-
-    if(_code != 0) {
-        if(is_perror) {
-            _what += ": ";
-            _what += strerror(errno);
+uint32_t timespec_us_diff(const struct timespec t1, const struct timespec t2) {
+    long nsec_diff = t1.tv_nsec - t2.tv_nsec;
+    time_t sec_diff = t1.tv_sec - t2.tv_sec;
+    if(nsec_diff < 0) {
+        nsec_diff += 1000*1000*1000;
+        sec_diff--;
     }
 
-        char remainder[20];
-        sprintf(remainder, " (code %d)", _code);
-        _what += remainder;
+    if(sec_diff > MAX_USEC_DIFF)
+        sec_diff = MAX_USEC_DIFF;
+    return (nsec_diff / 1000) + (sec_diff * 1000*1000);
 }
+
+uint32_t timespec_us_ellapsed(const struct timespec ref) {
+    struct timespec now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    return timespec_us_diff(now, ref);
+}
+
+uint32_t current_us_timestamp() {
+    struct timespec now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    return (now.tv_sec * 1000*1000) + (now.tv_nsec / 1000);
 }

util.hpp

@@ -1,7 +1,5 @@
 #pragma once
 
-#include <exception>
-#include <string>
 #include <netinet/in.h>
 
 /* Debugging -- taken from babeld */
@@ -58,36 +56,24 @@ inline uint32_t to_us_timestamp(uint32_t clock_output) {
 }
 
 
-/** in6_addr hash & equality */
-namespace std {
-    template<>
-    class hash<in6_addr> {
-        public:
-            size_t operator()(const in6_addr& addr) const;
-    };
-
-    template<>
-    class equal_to<in6_addr> {
-        public:
-            bool operator()(const in6_addr& lhs, const in6_addr& rhs) const;
-    };
-}
+/** Max seconds that can be be represented in a microseconds timestamp, on 31
+ * bits. */
+const uint32_t MAX_USEC_DIFF = ((1U<<31) - 1) / (1000*1000) - 1;
 
 
+/** Get a `struct timespec` difference, ie `t1 - t2`, as a new `struct
+ * timespec`. Assumes `t1 >= t2`. */
+void timespec_diff(
+        const struct timespec t1, const struct timespec t2,
+        struct timespec* result);
 
-/** MsgException -- an exception bearing a passed explanation message
- *
- * If `is_perror` is true, then the `strerror` corresponding message is appened
- * to the message in `what()`.
- */
-class MsgException : public std::exception {
-    public:
-        MsgException(const std::string& msg, int code=0, bool is_perror=false);
-        int errcode() const noexcept { return _code; }
-        const char* what() const noexcept { return _what.c_str(); };
+/** Get a `struct timespec` difference, ie `t1 - t2`, expressed in
+ * microseconds. Assumes `t1 >= t2`. Capped to MAX_USEC_DIFF seconds. */
+uint32_t timespec_us_diff(const struct timespec t1, const struct timespec t2);
 
-    private:
-        std::string _msg;
-        int _code;
-        std::string _what;
-};
+/** Get the number of microseconds ellapsed since a `struct timespec`, based on
+ * the monotonic clock */
+uint32_t timespec_us_ellapsed(const struct timespec ref);
+
+/** Get the current timestamp, in microseconds */
+uint32_t current_us_timestamp();