udp_proxy: support dropping a packet of a specific size

udp_proxy.c

@@ -79,6 +79,8 @@ int serverLen = sizeof(server); /* server address len */
 int dropPacket = 0; /* dropping packet interval */
 int delayPacket = 0; /* delay packet interval */
 int dropNth = 0;
+int dropBySize = 0; /* drop first packet of specific size */
+int dropSize = 0; /* specific size to drop */
 int dropPacketNo = 0;
 int dropSpecific = 0; /* specific seq to drop in epoch */
 int dropSpecificSeq = 0; /* specific seq to drop */
@@ -577,6 +579,12 @@ static void Msg(evutil_socket_t fd, short which, void* arg)
  return;
  }
 
+ if (dropBySize && ret == dropSize) {
+ LOG("*** but dropping the %d packet of size %d\n", msgCount, ret);
+ dropBySize = 0;
+ return;
+ }
+
  /* should we delay the current packet */
  if (delayPacket && (msgCount % delayPacket) == 0) {
  LOG("*** but delaying this packet\n");
@@ -773,6 +781,7 @@ static void Usage(void)
  printf("-l <log file> Use the provided argument as the log file\n");
  printf("-t <delays> Comma seperated list of delays for each \n"
  " subsequent packet in seconds.\n");
+ printf("-F <size> Drop first packet of <size> bytes\n");
 }
 
 
@@ -786,7 +795,7 @@ int main(int argc, char** argv)
 
  setlocale(LC_ALL, ""); /* Make portable */
 
- while ( (ch = GetOpt(argc, argv, "?Dap:s:d:y:x:b:R:S:r:f:ul:t:")) != -1) {
+ while ( (ch = GetOpt(argc, argv, "?Dap:s:d:y:x:b:R:S:r:f:ul:t:F:")) != -1) {
  switch (ch) {
  case '?' :
  Usage();
@@ -878,6 +887,11 @@ int main(int argc, char** argv)
  dropPacketNo = atoi(myoptarg);
  break;
 
+ case 'F':
+ dropBySize = 1;
+ dropSize = atoi(myoptarg);
+ break;
+
  case 'u':
  isDtls13 = 1;
  break;