向客户端发送100,000个UDP数据包（C套接字编程）

Question

I'm working on a cool project and I need to send 100,000 UDP Packets from a Server to a Client with a Packet-to-Packet Delay of 10ms. The Server is Debian Server with a public IP Address. The Client is an other Debian PC with LTE USB-Modem. The Client has no public IP Address and knows the public IP Address of my Server. My 4G/LTE Provider doesn't provide public IP Adresses to thier clients. I need to build a stable UDP Socket Connection but I'm struggling keeping the socket connection alive.

Can somebody help me?

thx

best regards

/**** CLIENT ****/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define PORT 20009

int main()
{
        int sock;
        int size;
        int nbytes, flags;
        int i;
        int a = 0;
        char * cp;
        char buffer[] = "012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789";

        struct sockaddr_in target_pc, me;

        sock = socket(PF_INET,SOCK_DGRAM,0);
        if(sock < 0)
        {
                printf("socket error = %d\n", sock);
                return -1;
        }

        target_pc.sin_family = PF_INET;
        target_pc.sin_port = htons(PORT);

        me.sin_family = PF_INET;
        me.sin_port = htons(0);
        me.sin_addr.s_addr = htonl(INADDR_ANY);
        i = bind(sock, (struct sockaddr *) &me, sizeof(me));

        if( i < 0)
        {
                printf("bind result: %d\n", i);
                return -1;
        }

        nbytes = 200;
        char str_addr[] = "155.55.25.25";
        target_pc.sin_addr.s_addr = inet_addr(&str_addr[0]);

        while(1)
        {
                nbytes = strlen(buffer);
                flags = 0;
                sendto(sock, (char *) buffer, nbytes,flags,(struct sockaddr *)&target_pc,sizeof(target_pc));
                int addrlen = sizeof(target_pc);
                size = recvfrom(sock, buffer, nbytes, flags, (struct sockaddr *)&target_pc,&addrlen);

                if((size > 0) && (size < 200))
                {
                        buffer[size] = '\0';
                        i = puts((char *) buffer);
                }
                printf("%i --- Size: %lu\n", a, sizeof(buffer));
                a = a + 1;

        }
        return 0;
}

Below my Server Code:

/*** SERVER ***/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#define PORT 20009

void SleepMs(int ms)
{
    usleep(ms*1000); //convert to microseconds
    return;
}

int main()
{
        int sock;
        int size;
        int nbytes, flags;
        socklen_t addrlen;

        int i;

        char buffer[100];
        char buffer2[] = "12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890\0";
        struct sockaddr_in server;
        struct sockaddr_in from;

        sock = socket(AF_INET,SOCK_DGRAM,0);
        if(sock < 0)
        {
                printf("socket error = %d\n", sock);
                return -1;
        }
        server.sin_family = AF_INET;
        server.sin_addr.s_addr = htonl(INADDR_ANY);

        server.sin_port = htons(PORT);

        i = bind(sock, (struct sockaddr *) &server, sizeof(server));

                if( i < 0){
                printf("bind result: %d\n", i);
                return -1;
        }
        else{
                printf("Simple UDP server is ready!\n");
        }

        nbytes = 200;
        flags = 0;

        while(1)
        {
                addrlen = sizeof(from);
                size = recvfrom(sock, buffer, nbytes, flags, (struct sockaddr *)&from, &addrlen);


                if((size > 0) && (size < 200))
                {
                        buffer[size] = '\0';
                        i = puts((char *) buffer);
                }
                printf("\n");
                sock = socket(PF_INET,SOCK_DGRAM,0);
                if(sock < 0)
                {
                        printf("socket error = %d\n", sock);
                        return -1;
                }

                sendto(sock, buffer2, nbytes, flags, (struct sockaddr *)&from,addrlen);
                SleepMs(10); // Packet-to-Packet Delay Time
      }
        return 0;
}

Answer 1

You can have the connection using IP of the server in this case 192.168.1.2

server.sin_addr.s_addr = inet_addr("192.168.1.2");

using this in both codes