added option to retransmit a packet

udp_proxy.c

@@ -59,6 +59,7 @@ int delayPacket = 0; /* delay packet interval */
 int dropSpecific = 0; /* specific seq to drop in epoch 0 */
 int delayByOne = 0; /* delay packet by 1 */
 int dupePackets = 0; /* duplicate all packets */
+int retxPacket = 0; /* specific seq to retransmit */
 
 typedef struct proxy_ctx {
  int clientFd; /* from client to proxy, downstream */
@@ -135,6 +136,22 @@ static int GetRecordSeq(const char* msg)
 }
 
 
+static void IncrementRecordSeq(char* msg)
+{
+ if (msg[3] == 0 && msg[4] == 0) {
+ unsigned long seq = (int)( msg[7] << 24 | msg[8] << 16 |
+ msg[9] << 8 | msg[10] );
+
+ seq++;
+
+ msg[7] = (char)(seq >> 24);
+ msg[8] = (char)(seq >> 16);
+ msg[9] = (char)(seq >> 8);
+ msg[10] = (char)seq;
+ }
+}
+
+
 /* msg callback, send along to peer or do manipulation */
 static void Msg(evutil_socket_t fd, short which, void* arg)
 {
@@ -226,6 +243,14 @@ static void Msg(evutil_socket_t fd, short which, void* arg)
  if (dupePackets)
  send(peerFd, msg, ret, 0);
 
+ if (retxPacket && GetRecordSeq(msg) == retxPacket
+ && side == serverSide) {
+
+ IncrementRecordSeq(msg);
+ send(peerFd, msg, ret, 0);
+ }
+
+
  if (delayByOne &&
  GetRecordSeq(msg) > delayByOne &&
  side == serverSide &&
@@ -332,6 +357,7 @@ static void Usage(void)
  printf("-y <num> Delay every <num> packet, default 0\n");
  printf("-b <num> Delay specific packet with sequence <num> by 1\n");
  printf("-D Duplicate all packets\n");
+ printf("-R <num> Retransmit packet sequence <num>\n");
 }
 
 
@@ -342,7 +368,7 @@ int main(int argc, char** argv)
  short port = -1;
  char* serverString = NULL;
 
- while ( (ch = getopt(argc, argv, "?Dp:s:d:y:x:b:")) != -1) {
+ while ( (ch = getopt(argc, argv, "?Dp:s:d:y:x:b:R:")) != -1) {
  switch (ch) {
  case '?' :
  Usage();
@@ -377,6 +403,10 @@ int main(int argc, char** argv)
  dupePackets = 1;
  break;
 
+ case 'R' :
+ retxPacket = atoi(optarg);
+ break;
+
  default:
  Usage();
  exit(EX_USAGE);