xref: /netbsd-src/external/bsd/ntp/dist/libntp/decodenetnum.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /*	$NetBSD: decodenetnum.c,v 1.6 2020/05/25 20:47:24 christos Exp $	*/
2 
3 /*
4  * decodenetnum - return a net number (this is crude, but careful)
5  */
6 #include <config.h>
7 #include <sys/types.h>
8 #include <ctype.h>
9 #ifdef HAVE_SYS_SOCKET_H
10 #include <sys/socket.h>
11 #endif
12 #ifdef HAVE_NETINET_IN_H
13 #include <netinet/in.h>
14 #endif
15 
16 #include "ntp.h"
17 #include "ntp_stdlib.h"
18 #include "ntp_assert.h"
19 
20 #define PORTSTR(x) _PORTSTR(x)
21 #define _PORTSTR(x) #x
22 
23 static int
24 isnumstr(
25 	const char *s
26 	)
27 {
28 	while (*s >= '0' && *s <= '9')
29 		++s;
30 	return !*s;
31 }
32 
33 /*
34  * decodenetnum		convert text IP address and port to sockaddr_u
35  *
36  * Returns 0 for failure, 1 for success.
37  */
38 int
39 decodenetnum(
40 	const char *num,
41 	sockaddr_u *netnum
42 	)
43 {
44 	static const char * const servicename = "ntp";
45 	static const char * const serviceport = PORTSTR(NTP_PORT);
46 
47 	struct addrinfo hints, *ai = NULL;
48 	int err;
49 	const char *host_str;
50 	const char *port_str;
51 	char *pp;
52 	char *np;
53 	char nbuf[80];
54 
55 	REQUIRE(num != NULL);
56 
57 	if (strlen(num) >= sizeof(nbuf)) {
58 		printf("length error\n");
59 		return FALSE;
60 	}
61 
62 	port_str = servicename;
63 	if ('[' != num[0]) {
64 		/*
65 		 * to distinguish IPv6 embedded colons from a port
66 		 * specification on an IPv4 address, assume all
67 		 * legal IPv6 addresses have at least two colons.
68 		 */
69 		pp = strchr(num, ':');
70 		if (NULL == pp)
71 			host_str = num;	/* no colons */
72 		else if (NULL != strchr(pp + 1, ':'))
73 			host_str = num;	/* two or more colons */
74 		else {			/* one colon */
75 			strlcpy(nbuf, num, sizeof(nbuf));
76 			host_str = nbuf;
77 			pp = strchr(nbuf, ':');
78 			*pp = '\0';
79 			port_str = pp + 1;
80 		}
81 	} else {
82 		host_str = np = nbuf;
83 		while (*++num && ']' != *num)
84 			*np++ = *num;
85 		*np = 0;
86 		if (']' == num[0] && ':' == num[1] && '\0' != num[2])
87 			port_str = &num[2];
88 	}
89 	if ( ! *host_str)
90 		return FALSE;
91 	if ( ! *port_str)
92 		port_str = servicename;
93 
94 	ZERO(hints);
95 	hints.ai_flags |= Z_AI_NUMERICHOST;
96 	if (isnumstr(port_str))
97 		hints.ai_flags |= Z_AI_NUMERICSERV;
98 	err = getaddrinfo(host_str, port_str, &hints, &ai);
99 	/* retry with default service name if the service lookup failed */
100 	if (err == EAI_SERVICE && strcmp(port_str, servicename)) {
101 		hints.ai_flags &= ~Z_AI_NUMERICSERV;
102 		port_str = servicename;
103 		err = getaddrinfo(host_str, port_str, &hints, &ai);
104 	}
105 	/* retry another time with default service port if the service lookup failed */
106 	if (err == EAI_SERVICE && strcmp(port_str, serviceport)) {
107 		hints.ai_flags |= Z_AI_NUMERICSERV;
108 		port_str = serviceport;
109 		err = getaddrinfo(host_str, port_str, &hints, &ai);
110 	}
111 	if (err != 0)
112 		return FALSE;
113 
114 	INSIST(ai->ai_addrlen <= sizeof(*netnum));
115 	ZERO(*netnum);
116 	memcpy(netnum, ai->ai_addr, ai->ai_addrlen);
117 	freeaddrinfo(ai);
118 
119 	return TRUE;
120 }
121