gistfile1.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <netinet/in.h>

// Network Packet Struct
typedef struct {
    int fd;
    struct sockaddr_in cli_addr;
    int length;
    char *buffer;
} NET_PACKET;
 
void receive_nonce( NET_PACKET *packet ) {
    
  printf( "Received nonce %s\n", packet->buffer );
 
}
 
void receive_payload( int fd, struct sockaddr_in *cli_addr, char *buffer, int length ) {
 
    NET_PACKET *packet = calloc( sizeof(NET_PACKET) + length + 1, 1);
    
    if( packet == NULL ) {
    printf( "failed.\n" );
    exit( EXIT_FAILURE );
    }
    
    packet->buffer = (char *)(packet + offsetof(NET_PACKET, buffer));
    memcpy(packet->buffer, buffer, strlen(buffer));
    
    receive_nonce( packet );
    
    free(packet);
}

int main(int argc, char *argv[]) {
    struct sockaddr_in cli_addr = { 0 };
    receive_payload(0, &cli_addr, "Hello", 6);
    return 0;
}