[Client] Add option -s (packet size)

owlps-client/owlps-client.c

@@ -35,8 +35,11 @@
 /* Delay between two requests in loop mode (in milliseconds) */
 #define DEFAULT_FLOOD_DELAY 1000
 
+/* Maximal size of a packet */
+#define MAX_PKT_SIZE 1450u
+
 /* Program arguments (getopt string) */
-#define OPTIONS "DF::hi:I:l::n:p:t:V"
+#define OPTIONS "DF::hi:I:l::n:p:s:t:V"
 
 
 /* Function headers */
@@ -49,8 +52,9 @@ void check_configuration(void) ;
 void print_configuration(void) ;
 #endif // DEBUG
 void create_socket(void) ;
-void make_packet(void) ;
 void send_request(void) ;
+void make_packet(void) ;
+void add_padding(void) ;
 #ifdef ENABLE_RECEIVE_POSITION
 int receive_position(void) ;
 #endif // ENABLE_RECEIVE_POSITION
@@ -66,6 +70,7 @@ struct {
   char iface[IFNAMSIZ + 1] ; // Source network interface
   int_fast32_t delay ; // Time between two packet transmissions
   uint_fast16_t nb_pkt ; // Number of packets to send
+  uint_fast16_t pkt_size ; // Size of the packet to send
   int_fast32_t flood_delay ; // Time between two request transmissions
   uint_fast16_t listening_port ;
   // Calibration data:
@@ -74,15 +79,16 @@ struct {
   float y ;
   float z ;
 } options = {
-  owl_false,
-  "",
-  OWL_DEFAULT_REQUEST_PORT,
-  "",
-  -1,
-  0,
-  -1,
-  0,
-  0, 0, 0, 0
+  owl_false, // daemon
+  "", // dest_ip
+  OWL_DEFAULT_REQUEST_PORT, // dest_port
+  "", // iface
+  -1, // delay
+  0, // nb_pkt
+  0, // pkt_size
+  -1, // flood_delay
+  0, // listening_port
+  0, 0, 0, 0 // Calibration data
 } ;
 
 char *program_name = NULL ;
@@ -233,6 +239,9 @@ void parse_main_options(int argc, char **argv)
         case 'p' :
           options.dest_port = strtoul(optarg, NULL, 0) ;
           break ;
+        case 's' :
+          options.pkt_size = strtoul(optarg, NULL, 0) ;
+          break ;
         case 't' :
           options.delay = strtol(optarg, NULL, 0) ;
           break ;
@@ -313,6 +322,17 @@ void check_configuration()
         options.nb_pkt = DEFAULT_NBPKT_NORMAL ;
     }
 
+  // Packet size too big
+  if (options.pkt_size > MAX_PKT_SIZE)
+    {
+#ifdef DEBUG
+      fprintf(stderr,
+              "Warning! pkt_size cannot be greater than %hu bytes:"
+              " failing back to %hu.\n", MAX_PKT_SIZE, MAX_PKT_SIZE) ;
+#endif // DEBUG
+      options.pkt_size = MAX_PKT_SIZE ;
+    }
+
   // Calibration request but bad direction
   if (is_calibration_request)
     if (options.direction < OWL_DIRECTION_MIN ||
@@ -456,6 +476,7 @@ void make_packet()
       packet_size =
         sizeof(uint8_t) * 2 + sizeof(owl_timestamp) + sizeof(float) * 3 +
         sizeof(uint16_t) * 2 ;
+      add_padding() ;
       packet = malloc(packet_size) ;
 
       // Packet type:
@@ -487,6 +508,7 @@ void make_packet()
       memcpy(&packet[offset], &options.y, sizeof(float)) ;
       offset += sizeof(float) ;
       memcpy(&packet[offset], &options.z, sizeof(float)) ;
+      offset += sizeof(float) ;
       // Convert the coordinates back to the host endianess (mandatory
       // in flood mode):
       options.x = owl_ntohf(options.x) ;
@@ -501,6 +523,7 @@ void make_packet()
       offset = 0 ;
       packet_size =
         sizeof(uint8_t) + sizeof(owl_timestamp) + sizeof(uint16_t) * 2 ;
+      add_padding() ;
       packet = malloc(packet_size) ;
 
       // Packet type:
@@ -515,9 +538,28 @@ void make_packet()
       offset += sizeof(uint16_t) ;
       // Request time:
       memcpy(&packet[offset], &request_time, sizeof(request_time)) ;
+      offset += sizeof(request_time) ;
     }
 
-  printf("Packet timestamp: %s\n", request_time_str) ;
+  // Initialize padding bytes with 0xFF:
+  while (offset < packet_size)
+    packet[offset++] = 0xFF ;
+
+  printf("Packet timestamp: %s\n"
+         "Packet size: %"PRIuFAST16"\n",
+         request_time_str,
+         packet_size) ;
+}
+
+
+
+/*
+ * Increases the packet size to add padding.
+ */
+void add_padding()
+{
+  if (options.pkt_size > packet_size)
+    packet_size = options.pkt_size ;
 }
 
 
@@ -561,9 +603,10 @@ void print_usage()
          " -i dest_ip"
          " [-p dest_port]"
          " [-I iface]"
-         "\n\t"
          " [-t delay]"
+         "\n\t"
          " [-n nb_packets]"
+         " [-s packet_size]"
          " [-F [delay] [-D]]"
          " [-l [port]]\n"
          "Calibration request:\n"
@@ -571,9 +614,10 @@ void print_usage()
          " -i dest_ip"
          " [-p dest_port]"
          " [-I iface]"
-         "\n\t"
          " [-t delay]"
+         "\n\t"
          " [-n nb_packets]"
+         " [-s packet_size]"
          " [-F [delay] [-D]]"
          " direction x y z\n"
 
@@ -590,6 +634,12 @@ void print_usage()
          "\t-n nb_packets\tNumber of packet transmitted for the request"
          " (default:\n\t\t\t%d for a normal request, %d for a"
          " calibration request).\n"
+         "\t-s packet_size\tData size of the transmitted packets. The"
+         " minimal value\n\t\t\tis the size of the request's data"
+         " fields; if packet_size\n\t\t\tis less than this size, it is"
+         " ignored. Note that this\n\t\t\tsize does not take into"
+         " account the headers, so the\n\t\t\twhole 802.11 frame will be"
+         " bigger.\n"
          "\t-I iface\tName of the network interface used to transmit the"
          "\n\t\t\trequest (e.g. \"eth2\"). If this option is absent, the"
          "\n\t\t\tinterface is selected automatically. You must be root"