initial

/*

 * Based on:

 *   https://www.geeksforgeeks.org/udp-server-client-implementation-c/

 */

// Server side implementation of UDP client-server model

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <stdbool.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#define PORT    44460

#define MAXLINE 1420

#define ANSI_COLOR_RED  "\x1b[31m"

#define ANSI_COLOR_RST  "\x1b[0m"

int parse_packet(char *buf){

  char *token;

  int cnt = 0;

  int res = -1;

  while ((token = strsep(&buf, "_")) != NULL){

    if (cnt==2){

      //printf("%s\n", token);

      res = atoi(token);

      break;

    }

    cnt++;

  }

  return res;

}

// server

int main(int argc, char **argv) {

    int fd;

    char buffer[MAXLINE];

    struct sockaddr_in servaddr, cliaddr;

    in_addr_t s_addr = INADDR_ANY;

    if (argc>1){

      if (!inet_aton(argv[1],&s_addr)){

        perror("Invalid inet addr in argv[1]");

        return -1;

      }

    }

    if ( (fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {

        perror("socket creation failed");

        exit(EXIT_FAILURE);

    }

    memset(&servaddr, 0, sizeof(servaddr));

    memset(&cliaddr,  0, sizeof(cliaddr));

    // Server info

    servaddr.sin_family      = AF_INET; // IPv4

    servaddr.sin_addr.s_addr = s_addr;

    servaddr.sin_port        = htons(PORT);

    // Bind the socket with the server address

    if ( bind(fd, (const struct sockaddr *)&servaddr, sizeof(servaddr)) < 0 )

    {

        perror("bind failed");

        exit(EXIT_FAILURE);

    }

    int cliaddr_len, n;

    bool first = true;

    /*

    if(first){

    	printf("Boolean type works\n");

    }

    */

    int pnum;

    int pnum_old=-1;

    int cnt = 0;

    printf("Listening at %s:%d\n",inet_ntoa(servaddr.sin_addr),PORT);

    // Receive

    while(true){

      n = recvfrom(fd, (char *)buffer, MAXLINE, 0, (struct sockaddr *) &cliaddr, (socklen_t *) &cliaddr_len);

      buffer[n] = '\0';

      //if (first && (cliaddr.sin_port!=0)){

      if (first){

    	  printf("Receiving from %s:%d (if 0s - cliaddr does not always get filled out)\n", inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));

    	  first = false;

      }

      pnum = parse_packet(buffer);

      //printf("packet %d\n",pnum);

      if (pnum_old!=-1){

        if ((pnum-pnum_old)!=1){

          printf(ANSI_COLOR_RED "PACKET LOSS, received:  %d, expected:  %d" ANSI_COLOR_RST "\n", pnum, pnum_old+1);

        }

      }

      pnum_old = pnum;

      cnt++;

    }

    return 0;

}

/*

 * Based on:

 *   https://www.geeksforgeeks.org/udp-server-client-implementation-c/

 */

// Server side implementation of UDP client-server model

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <stdbool.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#include <errno.h>

#include <sys/uio.h>

#include <sys/time.h>

#define PORT    44460

#define MAXLINE 1420-67

#define NUMBER_OF_PACKETS_IN_FRAME 10000000

#define ANSI_COLOR_RED  "\x1b[31m"

#define ANSI_COLOR_RST  "\x1b[0m"

int random_string(char *dest, size_t length) {

  char charset[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

    while (length-- > 0) {

        size_t index = (double) rand() / RAND_MAX * (sizeof charset - 1);

        *dest++ = charset[index];

    }

    *dest = '\0';

    return 0;

}

int generate_packet(char * buf, int pnum){

    char pnum_str[15];

    sprintf(pnum_str,"__%d__",pnum);

    //random_string(buf,MAXLINE);

    strncpy(buf,pnum_str,strlen(pnum_str));

    return 0;

}

//client

int main(int argc, char **argv) {

	struct timeval t0;

    int fd;

    char buffer[MAXLINE];

    int res = 0;

    struct sockaddr_in servaddr;

    in_addr_t s_addr = INADDR_ANY;

    if (argc>1){

      if (!inet_aton(argv[1],&s_addr)){

        perror("Invalid inet addr in argv[1]");

        return -1;

      }

    }

    if ( (fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {

        perror("socket creation failed");

        exit(EXIT_FAILURE);

    }

    memset(&servaddr, 0, sizeof(servaddr));

    // Server info

    servaddr.sin_family      = AF_INET; // IPv4

    servaddr.sin_addr.s_addr = s_addr;

    servaddr.sin_port        = htons(PORT);

	struct sockaddr_in saddr;

	memset(&saddr, 0, sizeof(struct sockaddr_in));

	saddr.sin_family = AF_INET;

	saddr.sin_port = htons(0);

	saddr.sin_addr.s_addr = htonl(INADDR_ANY);

	if (bind(fd, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in))<0){

		printf("BIND ERROR!");

	}

    printf("Sending to %s:%d\n",inet_ntoa(servaddr.sin_addr),PORT);

    int frame_cnt = 0;

    int pnum = 0;

    if (connect(fd,(const struct sockaddr *) &servaddr, sizeof(servaddr))<0){

    	printf("connect() error: %d",errno);

    	return -2;

    }

    // Send

    while(true){

      random_string(buffer,MAXLINE);

      for(int i=0;i<NUMBER_OF_PACKETS_IN_FRAME;i++){

    	gettimeofday(&t0, NULL);

        printf("packet: %06d,  time: %lu.%06d\n", pnum, t0.tv_sec, t0.tv_usec);

        generate_packet(buffer,pnum);

        // tested

        //res = sendto(fd, (const char *)buffer, strlen(buffer), 0, (const struct sockaddr *) &servaddr, sizeof(servaddr));

        // tested

        //res = write(fd,(const char *)buffer,strlen(buffer));

        //gettimeofday(&t0, NULL);

        //printf("time before2 : %lu.%06d\n", t0.tv_sec,t0.tv_usec);

        int iovcnt;

        struct iovec iov[3];

        char *buf1 = "This is a longer string\n";

        char *buf2 = "This is the longest string in this example\n";

        iov[0].iov_base = buffer;

        iov[0].iov_len = strlen(buffer);

        iov[1].iov_base = buf1;

        iov[1].iov_len = strlen(buf1);

        iov[2].iov_base = buf2;

        iov[2].iov_len = strlen(buf2);

        iovcnt = 3;

        res = writev(fd,iov,iovcnt);

        //gettimeofday(&t0, NULL);

        //printf("time after   : %lu.%06d\n", t0.tv_sec,t0.tv_usec);

        if (res<0){

          printf("    send result= %d,  errno= %d\n",res,errno);

        }else{

          //printf("    sent %d bytes\n",res);

        }

        pnum++;

      }

      //printf("%s\n",buffer);

      gettimeofday(&t0, NULL);

      printf("Sent frame %d, total packets %d @ %lu.%06d\n",frame_cnt, pnum,t0.tv_sec,t0.tv_usec);

      usleep(1000000);

      frame_cnt++;

    }

    return 0;

}