server_udp.zip_UDP_UDP_server_linux UDP_udp server

/* Creates a datagram server. The port number is passed as an argument. This server runs forever */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <stdio.h> void error(char *msg) { perror(msg); exit(0); } int main(int argc, char *argv[]) { int sock, length, fromlen, n; struct sockaddr_in server; struct sockaddr_in from; char buf[1024]; if (argc < 2) { fprintf(stderr, "ERROR, no port provided\n"); exit(0); } sock=socket(AF_INET, SOCK_DGRAM, 0); if (sock < 0) error("Opening socket"); length = sizeof(server); bzero(&server,length); server.sin_family=AF_INET; server.sin_addr.s_addr=INADDR_ANY; server.sin_port=htons(atoi(argv[1])); if (bind(sock,(struct sockaddr *)&server,length)<0) error("binding"); fromlen = sizeof(struct sockaddr_in); while (1) { n = recvfrom(sock,buf,1024,0,(struct sockaddr *)&from,&fromlen); if (n < 0) error("recvfrom"); write(1,"Received a datagram: ",21); write(1,buf,n); n = sendto(sock,"Got your message\n",17, 0,(struct sockaddr *)&from,fromlen); if (n < 0) error("sendto"); } }