/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id$
 */

#include "ipf.h"
#include <ctype.h>

int
getport(frentry_t *fr, char *name, u_short *port, char *proto)
{
        struct protoent *p;
        struct servent *s;
        u_short p1;

        if (fr == NULL || fr->fr_type != FR_T_IPF) {
                s = getservbyname(name, proto);
                if (s != NULL) {
                        *port = s->s_port;
                        return (0);
                }

                if (ISDIGIT(*name)) {
                        int portval = atoi(name);
                        if (portval < 0 || portval > 65535)
                                return (-1);
                        *port = htons((u_short)portval);
                        return (0);
                }
                return (-1);
        }

        /*
         * Some people will use port names in rules without specifying
         * either TCP or UDP because it is implied by the group head.
         * If we don't know the protocol, then the best we can do here is
         * to take either only the TCP or UDP mapping (if one or the other
         * is missing) or make sure both of them agree.
         */
        if (fr->fr_proto == 0) {
                s = getservbyname(name, "tcp");
                if (s != NULL)
                        p1 = s->s_port;
                else
                        p1 = 0;
                s = getservbyname(name, "udp");
                if (s != NULL) {
                        if (p1 != s->s_port)
                                return (-1);
                }
                if ((p1 == 0) && (s == NULL))
                        return (-1);
                if (p1)
                        *port = p1;
                else
                        *port = s->s_port;
                return (0);
        }

        if ((fr->fr_flx & FI_TCPUDP) != 0) {
                /*
                 * If a rule is "tcp/udp" then check that both TCP and UDP
                 * mappings for this protocol name match ports.
                 */
                s = getservbyname(name, "tcp");
                if (s == NULL)
                        return (-1);
                p1 = s->s_port;
                s = getservbyname(name, "udp");
                if (s == NULL || s->s_port != p1)
                        return (-1);
                *port = p1;
                return (0);
        }

        p = getprotobynumber(fr->fr_proto);
        s = getservbyname(name, p ? p->p_name : NULL);
        if (s != NULL) {
                *port = s->s_port;
                return (0);
        }
        return (-1);
}