getport.c revision 170268 
1/*	$FreeBSD: head/contrib/ipfilter/lib/getport.c 170268 2007-06-04 02:54:36Z darrenr $	*/
2
3/*
4 * Copyright (C) 2002-2005 by Darren Reed.
5 *
6 * See the IPFILTER.LICENCE file for details on licencing.
7 *
8 * $Id: getport.c,v 1.1.4.6 2006/06/16 17:21:00 darrenr Exp $
9 */
10
11#include "ipf.h"
12
13int getport(fr, name, port)
14frentry_t *fr;
15char *name;
16u_short *port;
17{
18	struct protoent *p;
19	struct servent *s;
20	u_short p1;
21
22	if (fr == NULL || fr->fr_type != FR_T_IPF) {
23		s = getservbyname(name, NULL);
24		if (s != NULL) {
25			*port = s->s_port;
26			return 0;
27		}
28		return -1;
29	}
30
31	/*
32	 * Some people will use port names in rules without specifying
33	 * either TCP or UDP because it is implied by the group head.
34	 * If we don't know the protocol, then the best we can do here is
35	 * to take either only the TCP or UDP mapping (if one or the other
36	 * is missing) or make sure both of them agree.
37	 */
38	if (fr->fr_proto == 0) {
39		s = getservbyname(name, "tcp");
40		if (s != NULL)
41			p1 = s->s_port;
42		else
43			p1 = 0;
44		s = getservbyname(name, "udp");
45		if (s != NULL) {
46			if (p1 != s->s_port)
47				return -1;
48		}
49		if ((p1 == 0) && (s == NULL))
50			return -1;
51		if (p1)
52			*port = p1;
53		else
54			*port = s->s_port;
55		return 0;
56	}
57
58	if ((fr->fr_flx & FI_TCPUDP) != 0) {
59		/*
60		 * If a rule is "tcp/udp" then check that both TCP and UDP
61		 * mappings for this protocol name match ports.
62		 */
63		s = getservbyname(name, "tcp");
64		if (s == NULL)
65			return -1;
66		p1 = s->s_port;
67		s = getservbyname(name, "udp");
68		if (s == NULL || s->s_port != p1)
69			return -1;
70		*port = p1;
71		return 0;
72	}
73
74	p = getprotobynumber(fr->fr_proto);
75	s = getservbyname(name, p ? p->p_name : NULL);
76	if (s != NULL) {
77		*port = s->s_port;
78		return 0;
79	}
80	return -1;
81}
82