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

   1 #include <arpa/inet.h>
   2
   3 #include "reorderer.h"
   4 #include "protocol.h"
   5
   6 #define PACKET_BUFFER_SIZE 100
   7
   8 using namespace std;
   9
  10 Reorderer::Reorderer(Protocol* sender)
  11         : sender(sender), last_seq(-1)
  12 {
  13 }
  14
  15 void Reorderer::send_packet(uint16_t proto, const string& data, int seq)
  16 {
  17         bool silence = false;
  18         if (packet_buffer.size() >= PACKET_BUFFER_SIZE) {
  19                 printf("Gave up waiting for packets [%d,%d>\n",
  20                         last_seq + 1, packet_buffer.top().seq);
  21                 silence = true;
  22                 last_seq = packet_buffer.top().seq - 1;
  23         }
  24
  25         GREPacket packet;
  26         packet.seq = seq;
  27         packet.proto = proto;
  28         packet.data = data;
  29         packet_buffer.push(packet);
  30
  31         while (!packet_buffer.empty() &&
  32                (last_seq == -1 || packet_buffer.top().seq <= last_seq + 1)) {
  33                 int front_seq = packet_buffer.top().seq;
  34                 if (front_seq < last_seq + 1) {
  35                         printf("Duplicate packet or way out-of-order: seq=%d front_seq=%d\n",
  36                                 front_seq, last_seq + 1);
  37                         packet_buffer.pop();
  38                         continue;
  39                 }
  40                 //if (packet_buffer.size() > 1) {
  41                 //      printf("seq=%d (REORDER %d)\n", front_seq, int(packet_buffer.size()));
  42                 //} else {
  43                 //      printf("seq=%d\n", front_seq);
  44                 //}
  45                 const string &data = packet_buffer.top().data;
  46                 check_ts_discontinuity(packet_buffer.top().proto, data, silence);
  47                 sender->send_packet(proto, data, seq);
  48                 packet_buffer.pop();
  49                 last_seq = front_seq;
  50                 if (!silence && !packet_buffer.empty()) {
  51                         printf("Reordering with packet buffer size %d: seq=%d new_front_seq=%d\n", int(packet_buffer.size()), front_seq, packet_buffer.top().seq);
  52                         silence = true;
  53                 }
  54         }
  55 }
  56
  57 void Reorderer::check_ts_discontinuity(uint16_t proto, const string &data, bool silence)
  58 {
  59         if (data.size() == 1344) {
  60                 for (int i = 0; i < 7; ++i) {
  61                         const char *pkt = &data[i * 188 + 28];
  62                         int pid = (ntohl(*(uint32_t *)(pkt)) & 0x1fff00) >> 8;
  63                         if (pid == 8191) {
  64                                 // stuffing, ignore
  65                                 continue;
  66                         }
  67                         int has_payload = pkt[3] & 0x10;
  68                         int cc = pkt[3] & 0xf;
  69                         if (has_payload) {
  70                                 int last_cc = ccs[pid];
  71                                 if (!silence && cc != ((last_cc + 1) & 0xf)) {
  72                                         printf("Pid %d discontinuity (expected %d, got %d)\n", pid, (last_cc + 1) & 0xf, cc);
  73                                 }
  74                                 ccs[pid] = cc;
  75                         }
  76                 }
  77         }
  78 }
  79