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

   1 #include <arpa/inet.h>
   2
   3 #include "reorderer.h"
   4 #include "protocol.h"
   5 #include "timeutil.h"
   6
   7 #define PACKET_BUFFER_SIZE 1000
   8 #define TIMEOUT_SEC 1.000
   9
  10 using namespace std;
  11
  12 Reorderer::Reorderer(Sender* sender)
  13         : sender(sender), last_seq(-1)
  14 {
  15         gettimeofday(&last_sent_packet, NULL);
  16 }
  17
  18 void Reorderer::send_packet(uint16_t proto, const string& data, int seq)
  19 {
  20         timeval now;
  21         gettimeofday(&now, NULL);
  22
  23         bool silence = false;
  24         if (packet_buffer.size() >= PACKET_BUFFER_SIZE) {
  25                 printf("Gave up waiting for packets [%d,%d> (buffer full)\n",
  26                         last_seq + 1, packet_buffer.top().seq);
  27                 silence = true;
  28                 last_seq = packet_buffer.top().seq - 1;
  29         } else if (!packet_buffer.empty() &&
  30                    tdiff(packet_buffer.top().ts, now) > TIMEOUT_SEC) {
  31                 printf("Gave up waiting for packets [%d,%d> (timeout)\n",
  32                         last_seq + 1, packet_buffer.top().seq);
  33                 silence = true;
  34                 last_seq = packet_buffer.top().seq - 1;
  35                 // TODO: Rerun immediately after we've cleared out,
  36                 // in case there are more timeouts.
  37         }
  38
  39         // In case of restarts.
  40         if (packet_buffer.empty() &&
  41             seq < last_seq &&
  42             tdiff(last_sent_packet, now) > 5.0) {
  43                 printf("No good data for five seconds, resetting sequence to %d\n", seq);
  44                 last_seq = seq - 1;
  45         }
  46
  47         GREPacket packet;
  48         packet.seq = seq;
  49         packet.proto = proto;
  50         packet.data = data;
  51         packet.ts = now;
  52         packet_buffer.push(packet);
  53
  54         while (!packet_buffer.empty() &&
  55                (last_seq == -1 || packet_buffer.top().seq <= last_seq + 1)) {
  56                 int front_seq = packet_buffer.top().seq;
  57                 if (front_seq < last_seq + 1) {
  58                         printf("Duplicate packet or way out-of-order: seq=%d front_seq=%d\n",
  59                                 front_seq, last_seq + 1);
  60                         packet_buffer.pop();
  61                         continue;
  62                 }
  63                 //if (packet_buffer.size() > 1) {
  64                 //      printf("seq=%d (REORDER %d)\n", front_seq, int(packet_buffer.size()));
  65                 //} else {
  66                 //      printf("seq=%d\n", front_seq);
  67                 //}
  68                 const string &data = packet_buffer.top().data;
  69                 check_ts_discontinuity(packet_buffer.top().proto, data, silence);
  70                 sender->send_packet(proto, data, seq);
  71                 packet_buffer.pop();
  72                 last_seq = front_seq;
  73                 last_sent_packet = now;
  74                 if (!silence && !packet_buffer.empty()) {
  75                         printf("Reordering with packet buffer size %d: seq=%d new_front_seq=%d\n", int(packet_buffer.size()), front_seq, packet_buffer.top().seq);
  76                         silence = true;
  77                 }
  78         }
  79 }
  80
  81 void Reorderer::check_ts_discontinuity(uint16_t proto, const string &data, bool silence)
  82 {
  83         if (data.size() == 1344) {
  84                 for (int i = 0; i < 7; ++i) {
  85                         const char *pkt = &data[i * 188 + 28];
  86                         int pid = (ntohl(*(uint32_t *)(pkt)) & 0x1fff00) >> 8;
  87                         if (pid == 8191) {
  88                                 // stuffing, ignore
  89                                 continue;
  90                         }
  91                         int has_payload = pkt[3] & 0x10;
  92                         int cc = pkt[3] & 0xf;
  93                         if (has_payload) {
  94                                 int last_cc = ccs[pid];
  95                                 if (!silence && cc != ((last_cc + 1) & 0xf)) {
  96                                         printf("Pid %d discontinuity (expected %d, got %d)\n", pid, (last_cc + 1) & 0xf, cc);
  97                                 }
  98                                 ccs[pid] = cc;
  99                         }
 100                 }
 101         }
 102 }
 103