Modelbahn/z21emu/udp.cc

/*
 *
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h> /* close() */
#include <string.h> /* memset() */

#include "udp.h"

char dnsip[NET_HOSTLEN];

int dns_filladdr (string host, string port, int ai_family, struct sockaddr_in *sAddr) {
    struct addrinfo hints, *res;
    int err;

    /* we have to complete the sAddr struct */
    bzero (&hints, sizeof (struct addrinfo));
    hints.ai_family = ai_family;
    hints.ai_socktype = SOCK_DGRAM;

    if ((err = getaddrinfo (host.c_str(), port.c_str(), &hints, &res)) < 0) {
    	fprintf (stdout, "dns_filladdr (getaddrinfo):%s\n", gai_strerror (err));
    	return -1;
    }

    memcpy (sAddr, res->ai_addr, res->ai_addrlen);
    freeaddrinfo (res);

    return 1;
};


UDPConnection::UDPConnection() {
	sock = -1;
	port = "";
	writecnt = 0;
	readcnt = 0;
};


UDPConnection::~UDPConnection() {
	Close();
}


void UDPConnection::Close () {
	if (sock > -1) close (sock);
	sock = -1;
}


int UDPConnection::Listen(int port) {
	struct sockaddr_in servAddr;

	/* socket creation */
	if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
		printf("%s: socket error: %s \n",__FUNCTION__, strerror(errno));
	    return 0;
	}

	/* bind local server port */
	servAddr.sin_family = AF_INET;
	servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servAddr.sin_port = htons(port);
	if (bind (sock, (struct sockaddr *) &servAddr,sizeof(servAddr)) < 0) {
		printf("%s: bind error: %s \n",__FUNCTION__, strerror(errno));
	    return 0;
	}
	return 1;
}


int UDPConnection::Listen(string port) {
	return Listen (atoi(port.c_str()));
}


long int UDPConnection::ReadTimeout(string *source, char *buffer, long int len, int timeout) {
	int i;

	i = isData(timeout);
	if (i > 0) {
		return Read (source, buffer, len);
	}
	else
		return i;
}

long int UDPConnection::Read(string *source, char *buffer, long int len) {
	int n;
	socklen_t addrlen;
	sockaddr_in srcAddr;

	if (!isListen()) return -1;

	memset(buffer, 0x0, len);

    addrlen = sizeof(srcAddr);
    n = recvfrom(sock, buffer, len, 0, (sockaddr *) &srcAddr, &addrlen);
    if(n<0) {
    	printf("%s: recvfrom error:%s\n",__FUNCTION__, strerror(errno));
    	return -1;
    }

    /* print received message */
    char addr[NET_HOSTLEN];
   snprintf (addr, NET_HOSTLEN, "%s:%d", inet_ntoa(srcAddr.sin_addr), ntohs(srcAddr.sin_port));
   (*source) = (char*)addr;

    return n;
}


long int UDPConnection::Send(string destaddr, char *buffer, long int len) {
	int s;
	int addrlen = sizeof (struct sockaddr_in);
	sockaddr_in dstAddr;
	string host;
	string port;

	if (!isListen()) {
		/* socket creation */
		if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
			printf("%s: socket error: %s \n",__FUNCTION__, strerror(errno));
		    return -1;
		}
	}
	else s = sock;

	int pos = destaddr.rfind(':', destaddr.length());
	if (pos == -1) {
		port = "NET_PORT";
		host = destaddr;
	}
	else {
		port = destaddr.substr (pos+1, destaddr.length() - pos);
		host = destaddr.substr (0, pos);
	}

	dns_filladdr (host, port, PF_INET, &dstAddr);
	if (sendto (s, buffer, len, 0, (sockaddr *) &dstAddr, addrlen) == -1) {
		printf("%s: sendto error: %s \n",__FUNCTION__, strerror(errno));
	    return -1;
	}

	if (!isListen()) close (s);

	return 1;
}

int UDPConnection::isListen() {
	return (sock != -1);
}

int UDPConnection::isData(int timeout) {
	fd_set sockset;
	struct timeval tval;

	if (sock <= 0) {
		printf ("isData:socket error\n");
		return -1;
	}

	FD_ZERO (&sockset);
	FD_SET (sock, &sockset);
	tval.tv_sec = timeout / 1000;
	tval.tv_usec = (timeout % 1000);

	if (select (sock + 1, &sockset, NULL, NULL, &tval) >= 0) { 
		if (FD_ISSET (sock, &sockset)) {
			return 1;
		}
	}
	return 0;
}