initial

receiver.c

+/*
+ * 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;
+}

sender.c

+/*
+ * 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;
+}