Symmetria

#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/timeb.h>

#define PORT 7890
#define PACKET_DELAY 50

void diep(char *stringz)
{
   perror(stringz);
   exit(-1);
}

struct s_timestamp {
        int sequence;
        int tseconds;
        int tmilli;
        int total_packets; /* Tell the server how many packets we're sending */
        int padding_size;
        char *padding;
};

void delay_time(int PACKETDELAY) {
   int t_diff = 0;
   struct timeb t_delay_s, t_delay_e;

   memset(&t_delay_s, sizeof(struct timeb), 0);
   memset(&t_delay_e, sizeof(struct timeb), 0);
   ftime(&t_delay_s);
   while(t_diff < PACKETDELAY) {
     ftime(&t_delay_e);
     t_diff=(1000 * (t_delay_e.time - t_delay_s.time) + (t_delay_e.millitm - t_delay_s.millitm));
   }
}

int main(int argc, char *argv[]) {
   struct sockaddr_in udp_socket;
   char payload[sizeof(struct timeb)];
   int u_sock, counter, NUM_PACKETS, socklen=sizeof(udp_socket);
   struct s_timestamp p_data;
   struct timeb t_current;
   char IP_ADDRESS[20];
   int p_size;

   if(argc < 4) {
     printf("Usage: %s IP_ADDRESS NUM_PACKETS PAD_AMOUNT\n", argv[0]);
     exit(-1);
   }

   memset(&IP_ADDRESS, '\0', 20);
   memcpy((char *)&IP_ADDRESS, argv[1], strlen(argv[1]));
   printf("Found IP address %s\n",&IP_ADDRESS);

   if(!(NUM_PACKETS = atoi(argv[2])))  {
     printf("Invalid number of packets specified\n");
     exit(-1);

   }
   else printf("Sending %d packets...\n", NUM_PACKETS);

   if(!(atoi(argv[3]))) {
     printf("Invalid padding specified\n");
     exit(-1);
   }
   else {
     p_data.padding = malloc(atoi(argv[3]));
     p_size=atoi(argv[3]);
   }

   if((u_sock=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
        diep("socket");

   memset((char *)&udp_socket, 0, sizeof(udp_socket));

   udp_socket.sin_family = AF_INET;
   udp_socket.sin_port = htons(PORT);

    if (inet_aton((char *)&IP_ADDRESS, &udp_socket.sin_addr)==0) {
       fprintf(stderr, "inet_aton() failed\n");
       exit(1);
   }


//   memset(&p_data, sizeof(struct s_timestamp),0);
   memset(&p_data, p_size + sizeof(struct s_timestamp) ,0);

   p_data.padding_size = p_size;

   p_size = p_size + sizeof(struct s_timestamp);

   p_data.total_packets = NUM_PACKETS;
   p_data.padding_size = p_size - sizeof(struct s_timestamp);;
   if (sendto(u_sock, (void *)&p_data, p_size, 0, (struct sockaddr *)&udp_socket, socklen) == -1)
      diep("sendto()");

   for(counter = 0; counter < NUM_PACKETS; counter++) {
      memset(&p_data, p_size ,0);
      p_data.padding_size = p_size - sizeof(struct s_timestamp);
      printf("Sending packet %d\n", counter);
      ftime(&t_current);
      p_data.tseconds = t_current.time;
      p_data.tmilli = t_current.millitm;
      p_data.sequence=counter;
      p_data.total_packets = NUM_PACKETS;
      printf("Transmitting packet with sequence number %d\n",p_data.sequence);
      if (sendto(u_sock, (void *)&p_data, p_size, 0, (struct sockaddr *)&udp_socket, socklen) == -1)
        diep("sendto()");
      delay_time(PACKET_DELAY);
      }
   printf("Size of struct s_timestamp is %d\n",p_size);
}