xref: /freebsd/sbin/ipf/libipf/getport.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 
2 /*
3  * Copyright (C) 2012 by Darren Reed.
4  *
5  * See the IPFILTER.LICENCE file for details on licencing.
6  *
7  * $Id$
8  */
9 
10 #include "ipf.h"
11 #include <ctype.h>
12 
13 int
14 getport(frentry_t *fr, char *name, u_short *port, char *proto)
15 {
16 	struct protoent *p;
17 	struct servent *s;
18 	u_short p1;
19 
20 	if (fr == NULL || fr->fr_type != FR_T_IPF) {
21 		s = getservbyname(name, proto);
22 		if (s != NULL) {
23 			*port = s->s_port;
24 			return (0);
25 		}
26 
27 		if (ISDIGIT(*name)) {
28 			int portval = atoi(name);
29 			if (portval < 0 || portval > 65535)
30 				return (-1);
31 			*port = htons((u_short)portval);
32 			return (0);
33 		}
34 		return (-1);
35 	}
36 
37 	/*
38 	 * Some people will use port names in rules without specifying
39 	 * either TCP or UDP because it is implied by the group head.
40 	 * If we don't know the protocol, then the best we can do here is
41 	 * to take either only the TCP or UDP mapping (if one or the other
42 	 * is missing) or make sure both of them agree.
43 	 */
44 	if (fr->fr_proto == 0) {
45 		s = getservbyname(name, "tcp");
46 		if (s != NULL)
47 			p1 = s->s_port;
48 		else
49 			p1 = 0;
50 		s = getservbyname(name, "udp");
51 		if (s != NULL) {
52 			if (p1 != s->s_port)
53 				return (-1);
54 		}
55 		if ((p1 == 0) && (s == NULL))
56 			return (-1);
57 		if (p1)
58 			*port = p1;
59 		else
60 			*port = s->s_port;
61 		return (0);
62 	}
63 
64 	if ((fr->fr_flx & FI_TCPUDP) != 0) {
65 		/*
66 		 * If a rule is "tcp/udp" then check that both TCP and UDP
67 		 * mappings for this protocol name match ports.
68 		 */
69 		s = getservbyname(name, "tcp");
70 		if (s == NULL)
71 			return (-1);
72 		p1 = s->s_port;
73 		s = getservbyname(name, "udp");
74 		if (s == NULL || s->s_port != p1)
75 			return (-1);
76 		*port = p1;
77 		return (0);
78 	}
79 
80 	p = getprotobynumber(fr->fr_proto);
81 	s = getservbyname(name, p ? p->p_name : NULL);
82 	if (s != NULL) {
83 		*port = s->s_port;
84 		return (0);
85 	}
86 	return (-1);
87 }
88