xref: /freebsd/lib/libc/net/getnameinfo.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
1 /*
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 /*
33  * Issues to be discussed:
34  * - Thread safe-ness must be checked
35  * - Return values.  There seems to be no standard for return value (RFC2553)
36  *   but INRIA implementation returns EAI_xxx defined for getaddrinfo().
37  */
38 
39 #include <sys/types.h>
40 #include <sys/socket.h>
41 #include <net/if.h>
42 #include <netinet/in.h>
43 #include <arpa/inet.h>
44 #include <arpa/nameser.h>
45 #include <netdb.h>
46 #include <resolv.h>
47 #include <string.h>
48 #include <stddef.h>
49 
50 #define	SUCCESS 0
51 #define	ANY 0
52 #define	YES 1
53 #define	NO  0
54 
55 static struct afd {
56 	int a_af;
57 	int a_addrlen;
58 	int a_socklen;
59 	int a_off;
60 } afdl [] = {
61 #ifdef INET6
62 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
63 		offsetof(struct sockaddr_in6, sin6_addr)},
64 #endif
65 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
66 		offsetof(struct sockaddr_in, sin_addr)},
67 	{0, 0, 0},
68 };
69 
70 struct sockinet {
71 	u_char	si_len;
72 	u_char	si_family;
73 	u_short	si_port;
74 };
75 
76 #define	ENI_NOSOCKET 	0
77 #define	ENI_NOSERVHOST	1
78 #define	ENI_NOHOSTNAME	2
79 #define	ENI_MEMORY	3
80 #define	ENI_SYSTEM	4
81 #define	ENI_FAMILY	5
82 #define	ENI_SALEN	6
83 
84 int
85 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
86 	const struct sockaddr *sa;
87 	size_t salen;
88 	char *host;
89 	size_t hostlen;
90 	char *serv;
91 	size_t servlen;
92 	int flags;
93 {
94 	struct afd *afd;
95 	struct servent *sp;
96 	struct hostent *hp;
97 	u_short port;
98 	int family, i;
99 	char *addr, *p;
100 	u_long v4a;
101 	int h_error;
102 	char numserv[512];
103 	char numaddr[512];
104 	int noserv = 0;
105 
106 	if (sa == NULL)
107 		return ENI_NOSOCKET;
108 
109 	if (sa->sa_len != salen)
110 		return ENI_SALEN;
111 
112 	family = sa->sa_family;
113 	for (i = 0; afdl[i].a_af; i++)
114 		if (afdl[i].a_af == family) {
115 			afd = &afdl[i];
116 			goto found;
117 		}
118 	return ENI_FAMILY;
119 
120  found:
121 	if (salen != afd->a_socklen)
122 		return ENI_SALEN;
123 
124 	port = ((struct sockinet *)sa)->si_port; /* network byte order */
125 	addr = (char *)sa + afd->a_off;
126 
127 	if (serv == NULL || servlen == 0) {
128 		noserv = 1;
129 	} else {
130 		if (flags & NI_NUMERICSERV)
131 			sp = NULL;
132 		else {
133 			sp = getservbyport(port,
134 				(flags & NI_DGRAM) ? "udp" : "tcp");
135 		}
136 		if (sp) {
137 			if (strlen(sp->s_name) > servlen)
138 				return ENI_MEMORY;
139 			strcpy(serv, sp->s_name);
140 		} else {
141 			snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
142 			if (strlen(numserv) > servlen)
143 				return ENI_MEMORY;
144 			strcpy(serv, numserv);
145 		}
146 	}
147 
148 	switch (sa->sa_family) {
149 	case AF_INET:
150 		v4a = ntohl(((struct sockaddr_in *)sa)->sin_addr.s_addr);
151 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
152 			flags |= NI_NUMERICHOST;
153 		v4a >>= IN_CLASSA_NSHIFT;
154 		if (v4a == 0)
155 			flags |= NI_NUMERICHOST;
156 		break;
157 #ifdef INET6
158 	case AF_INET6:
159 	    {
160 		struct sockaddr_in6 *sin6;
161 		sin6 = (struct sockaddr_in6 *)sa;
162 		if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
163 		    IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
164 			flags |= NI_NUMERICHOST;
165 	    }
166 		break;
167 #endif
168 	}
169 	if (host == NULL || hostlen == 0) {
170 		if (noserv == 1)
171 			return ENI_NOSERVHOST;
172 	} else if (flags & NI_NUMERICHOST) {
173 		/* NUMERICHOST and NAMEREQD conflicts with each other */
174 		if (flags & NI_NAMEREQD)
175 			return ENI_NOHOSTNAME;
176 		if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
177 		    == NULL)
178 			return ENI_SYSTEM;
179 		if (strlen(numaddr) > hostlen)
180 			return ENI_MEMORY;
181 		strcpy(host, numaddr);
182 #ifdef INET6
183 		if (afd->a_af == AF_INET6 &&
184 		    (IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)addr) ||
185 		     IN6_IS_ADDR_MULTICAST((struct in6_addr *)addr)) &&
186 		    ((struct sockaddr_in6 *)sa)->sin6_scope_id) {
187 			if (flags & NI_WITHSCOPEID) {
188 				char *ep = strchr(host, '\0');
189 				unsigned int ifindex =
190 					((struct sockaddr_in6 *)sa)->sin6_scope_id;
191 				char ifname[IF_NAMESIZE * 2 /* for safety */];
192 				int scopelen, numaddrlen;
193 
194 				if ((if_indextoname(ifindex, ifname)) == NULL)
195 					return ENI_SYSTEM;
196 				scopelen = strlen(ifname);
197 				numaddrlen = strlen(host);
198 				if (numaddrlen + 1 /* SCOPE_DELIMITER */
199 				    + scopelen > hostlen)
200 					return ENI_MEMORY;
201 				/*
202 				 * Construct <numeric-addr><delim><scopeid>
203 				 */
204 				memcpy(host + numaddrlen + 1, ifname, scopelen);
205 				host[numaddrlen] = SCOPE_DELIMITER;
206 				host[numaddrlen + 1 + scopelen] = '\0';
207 			}
208 		}
209 #endif /* INET6 */
210 	} else {
211 		hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
212 		if (hp) {
213 			if (flags & NI_NOFQDN) {
214 				p = strchr(hp->h_name, '.');
215 				if (p) *p = '\0';
216 			}
217 			if (strlen(hp->h_name) > hostlen) {
218 				freehostent(hp);
219 				return ENI_MEMORY;
220 			}
221 			strcpy(host, hp->h_name);
222 			freehostent(hp);
223 		} else {
224 			if (flags & NI_NAMEREQD)
225 				return ENI_NOHOSTNAME;
226 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
227 			    == NULL)
228 				return ENI_NOHOSTNAME;
229 			if (strlen(numaddr) > hostlen)
230 				return ENI_MEMORY;
231 			strcpy(host, numaddr);
232 		}
233 	}
234 	return SUCCESS;
235 }
236