UDP.rar_arm udp_magic

#include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/wait.h> #include <sys/socket.h> #define PORT 5000 // The port which is communicate with server #define BACKLOG 10 #define LENGTH 512 // Buffer length int main () { int sockfd; // Socket file descriptor int nsockfd; // New Socket file descriptor int num; int sin_size; // to store struct size char revbuf[LENGTH]; // Send buffer struct sockaddr_in addr_local; struct sockaddr_in addr_remote; /* Get the Socket file descriptor */ if( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 ) { printf ("ERROR: Cannot obtain Socket Despcritor\n"); return (0); } else { printf ("OK: Obtain Socket Despcritor sucessfully\n"); } /* Fill the local socket address struct */ addr_local.sin_family = AF_INET; // Protocol Family addr_local.sin_port = htons(PORT); // Port number addr_local.sin_addr.s_addr = INADDR_ANY; // AutoFill local address bzero(&(addr_local.sin_zero), 8); // Flush the rest of struct /* Blind a special Port */ if( bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1 ) { printf ("ERROR: Cannot bind Port %d\n",PORT); return (0); } else { printf("OK: Bind the Port %d sucessfully\n",PORT); } sin_size = sizeof(struct sockaddr); if(num = recvfrom(sockfd, revbuf, LENGTH, 0, (struct sockaddr *)&addr_remote, &sin_size) == -1) { printf("ERROR!\n"); } else { printf("OK: %s\n",revbuf); } close(sockfd); return (0); }