git.sesse.net Git - greproxy/blob - pacer.cpp

   1 #include "pacer.h"
   2 #include "timeutil.h"
   3
   4 #include <algorithm>
   5
   6 using namespace std;
   7
   8 Pacer::Pacer(Sender *sender, int max_rate_kbit_per_sec, int burst_num_packets)
   9         : sender(sender), burst_num_packets(burst_num_packets), next_send_packet{0, 0}
  10 {
  11         const int max_rate_byte_per_sec = 1000 * max_rate_kbit_per_sec / 8;
  12         seconds_per_byte = 1.0 / max_rate_byte_per_sec;
  13 }
  14
  15 void Pacer::send_packet(uint16_t proto, const string &data, uint32_t incoming_seq)
  16 {
  17         waiting_packets.push_back(GREPacket{incoming_seq, proto, data, {0, 0}});
  18         possibly_flush_packets();
  19 }
  20
  21 void Pacer::possibly_adjust_tv(timeval *tv)
  22 {
  23         if (waiting_packets.empty()) {
  24                 return;
  25         }
  26
  27         timeval now;
  28         gettimeofday(&now, NULL);
  29
  30         timeval tdiff = subtract_timeval_saturate(next_send_packet, now);
  31         if (less_than(tdiff, *tv)) {
  32                 *tv = tdiff;
  33         }
  34 }
  35
  36 void Pacer::possibly_flush_packets()
  37 {
  38         if (waiting_packets.empty()) {
  39                 return;
  40         }
  41
  42         timeval now;
  43         gettimeofday(&now, NULL);
  44         if (less_than(now, next_send_packet)) {
  45                 return;
  46         }
  47
  48         int bytes_sent = 0;
  49         for (int i = 0; i < burst_num_packets && !waiting_packets.empty(); ++i) {
  50                 const GREPacket &packet = waiting_packets.front();
  51                 sender->send_packet(packet.proto, packet.data, packet.seq);
  52                 bytes_sent += packet.data.size();
  53                 waiting_packets.pop_front();
  54         }
  55
  56         next_send_packet = offset_timeval_seconds(now, seconds_per_byte * bytes_sent);
  57 }
  58