1 /*
2  * Copyright (C) 2000-2003 Damien Miller.  All rights reserved.
3  * Copyright (C) 1999 WIDE Project.  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 
30 /*
31  * Pseudo-implementation of RFC2553 name / address resolution functions
32  *
33  * But these functions are not implemented correctly. The minimum subset
34  * is implemented for ssh use only. For example, this routine assumes
35  * that ai_family is AF_INET. Don't use it for another purpose.
36  */
37 
38 #include "includes.h"
39 
40 #include <stdlib.h>
41 #include <string.h>
42 
43 #include <netinet/in.h>
44 #include <arpa/inet.h>
45 
46 #ifndef HAVE_GETNAMEINFO
getnameinfo(const struct sockaddr * sa,size_t salen,char * host,size_t hostlen,char * serv,size_t servlen,int flags)47 int getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
48 		size_t hostlen, char *serv, size_t servlen, int flags)
49 {
50 	struct sockaddr_in *sin = (struct sockaddr_in *)sa;
51 	struct hostent *hp;
52 	char tmpserv[16];
53 
54 	if (sa->sa_family != AF_UNSPEC && sa->sa_family != AF_INET)
55 		return (EAI_FAMILY);
56 	if (serv != NULL) {
57 		snprintf(tmpserv, sizeof(tmpserv), "%d", ntohs(sin->sin_port));
58 		if (strlcpy(serv, tmpserv, servlen) >= servlen)
59 			return (EAI_MEMORY);
60 	}
61 
62 	if (host != NULL) {
63 		if (flags & NI_NUMERICHOST) {
64 			if (strlcpy(host, inet_ntoa(sin->sin_addr),
65 			    hostlen) >= hostlen)
66 				return (EAI_MEMORY);
67 			else
68 				return (0);
69 		} else {
70 			hp = gethostbyaddr((char *)&sin->sin_addr,
71 			    sizeof(struct in_addr), AF_INET);
72 			if (hp == NULL)
73 				return (EAI_NODATA);
74 
75 			if (strlcpy(host, hp->h_name, hostlen) >= hostlen)
76 				return (EAI_MEMORY);
77 			else
78 				return (0);
79 		}
80 	}
81 	return (0);
82 }
83 #endif /* !HAVE_GETNAMEINFO */
84 
85 #ifndef HAVE_GAI_STRERROR
86 #ifdef HAVE_CONST_GAI_STRERROR_PROTO
87 const char *
88 #else
89 char *
90 #endif
gai_strerror(int err)91 gai_strerror(int err)
92 {
93 	switch (err) {
94 	case EAI_NODATA:
95 		return ("no address associated with name");
96 	case EAI_MEMORY:
97 		return ("memory allocation failure.");
98 	case EAI_NONAME:
99 		return ("nodename nor servname provided, or not known");
100 	case EAI_FAMILY:
101 		return ("ai_family not supported");
102 	default:
103 		return ("unknown/invalid error.");
104 	}
105 }
106 #endif /* !HAVE_GAI_STRERROR */
107 
108 #ifndef HAVE_FREEADDRINFO
109 void
freeaddrinfo(struct addrinfo * ai)110 freeaddrinfo(struct addrinfo *ai)
111 {
112 	struct addrinfo *next;
113 
114 	for(; ai != NULL;) {
115 		next = ai->ai_next;
116 		free(ai);
117 		ai = next;
118 	}
119 }
120 #endif /* !HAVE_FREEADDRINFO */
121 
122 #ifndef HAVE_GETADDRINFO
123 static struct
malloc_ai(int port,u_long addr,const struct addrinfo * hints)124 addrinfo *malloc_ai(int port, u_long addr, const struct addrinfo *hints)
125 {
126 	struct addrinfo *ai;
127 
128 	ai = malloc(sizeof(*ai) + sizeof(struct sockaddr_in));
129 	if (ai == NULL)
130 		return (NULL);
131 
132 	memset(ai, '\0', sizeof(*ai) + sizeof(struct sockaddr_in));
133 
134 	ai->ai_addr = (struct sockaddr *)(ai + 1);
135 	/* XXX -- ssh doesn't use sa_len */
136 	ai->ai_addrlen = sizeof(struct sockaddr_in);
137 	ai->ai_addr->sa_family = ai->ai_family = AF_INET;
138 
139 	((struct sockaddr_in *)(ai)->ai_addr)->sin_port = port;
140 	((struct sockaddr_in *)(ai)->ai_addr)->sin_addr.s_addr = addr;
141 
142 	/* XXX: the following is not generally correct, but does what we want */
143 	if (hints->ai_socktype)
144 		ai->ai_socktype = hints->ai_socktype;
145 	else
146 		ai->ai_socktype = SOCK_STREAM;
147 
148 	if (hints->ai_protocol)
149 		ai->ai_protocol = hints->ai_protocol;
150 
151 	return (ai);
152 }
153 
154 int
getaddrinfo(const char * hostname,const char * servname,const struct addrinfo * hints,struct addrinfo ** res)155 getaddrinfo(const char *hostname, const char *servname,
156     const struct addrinfo *hints, struct addrinfo **res)
157 {
158 	struct hostent *hp;
159 	struct servent *sp;
160 	struct in_addr in;
161 	int i;
162 	long int port;
163 	u_long addr;
164 
165 	port = 0;
166 	if (hints && hints->ai_family != AF_UNSPEC &&
167 	    hints->ai_family != AF_INET)
168 		return (EAI_FAMILY);
169 	if (servname != NULL) {
170 		char *cp;
171 
172 		port = strtol(servname, &cp, 10);
173 		if (port > 0 && port <= 65535 && *cp == '\0')
174 			port = htons(port);
175 		else if ((sp = getservbyname(servname, NULL)) != NULL)
176 			port = sp->s_port;
177 		else
178 			port = 0;
179 	}
180 
181 	if (hints && hints->ai_flags & AI_PASSIVE) {
182 		addr = htonl(0x00000000);
183 		if (hostname && inet_aton(hostname, &in) != 0)
184 			addr = in.s_addr;
185 		*res = malloc_ai(port, addr, hints);
186 		if (*res == NULL)
187 			return (EAI_MEMORY);
188 		return (0);
189 	}
190 
191 	if (!hostname) {
192 		*res = malloc_ai(port, htonl(0x7f000001), hints);
193 		if (*res == NULL)
194 			return (EAI_MEMORY);
195 		return (0);
196 	}
197 
198 	if (inet_aton(hostname, &in)) {
199 		*res = malloc_ai(port, in.s_addr, hints);
200 		if (*res == NULL)
201 			return (EAI_MEMORY);
202 		return (0);
203 	}
204 
205 	/* Don't try DNS if AI_NUMERICHOST is set */
206 	if (hints && hints->ai_flags & AI_NUMERICHOST)
207 		return (EAI_NONAME);
208 
209 	hp = gethostbyname(hostname);
210 	if (hp && hp->h_name && hp->h_name[0] && hp->h_addr_list[0]) {
211 		struct addrinfo *cur, *prev;
212 
213 		cur = prev = *res = NULL;
214 		for (i = 0; hp->h_addr_list[i]; i++) {
215 			struct in_addr *in = (struct in_addr *)hp->h_addr_list[i];
216 
217 			cur = malloc_ai(port, in->s_addr, hints);
218 			if (cur == NULL) {
219 				if (*res != NULL)
220 					freeaddrinfo(*res);
221 				return (EAI_MEMORY);
222 			}
223 			if (prev)
224 				prev->ai_next = cur;
225 			else
226 				*res = cur;
227 
228 			prev = cur;
229 		}
230 		return (0);
231 	}
232 
233 	return (EAI_NODATA);
234 }
235 #endif /* !HAVE_GETADDRINFO */
236