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      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 
     30 /*
     31  * Issues to be discussed:
     32  * - Thread safe-ness must be checked
     33  * - Return values.  There seems to be no standard for return value (RFC2553)
     34  *   but INRIA implementation returns EAI_xxx defined for getaddrinfo().
     35  * - RFC2553 says that we should raise error on short buffer.  X/Open says
     36  *   we need to truncate the result.  We obey RFC2553 (and X/Open should be
     37  *   modified).
     38  */
     39 
     40 #ifdef HAVE_CONFIG_H
     41 #include <config.h>
     42 #endif
     43 
     44 #ifndef lint
     45 static const char rcsid[] _U_ =
     46      "@(#) $Header: /tcpdump/master/tcpdump/missing/getnameinfo.c,v 1.11 2003-11-16 09:36:49 guy Exp $";
     47 #endif
     48 
     49 #include <sys/types.h>
     50 #include <sys/socket.h>
     51 #include <net/if.h>
     52 #include <netinet/in.h>
     53 #include <arpa/inet.h>
     54 #include <arpa/nameser.h>
     55 #include <netdb.h>
     56 #include <resolv.h>
     57 #include <string.h>
     58 #include <stddef.h>
     59 #include <errno.h>
     60 
     61 #ifdef NEED_ADDRINFO_H
     62 #include "addrinfo.h"
     63 #endif
     64 
     65 #define SUCCESS 0
     66 #define ANY 0
     67 #define YES 1
     68 #define NO  0
     69 
     70 static struct afd {
     71 	int a_af;
     72 	int a_addrlen;
     73 	int a_socklen;
     74 	int a_off;
     75 } afdl [] = {
     76 #ifdef INET6
     77 	{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
     78 		offsetof(struct sockaddr_in6, sin6_addr)},
     79 #endif
     80 	{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
     81 		offsetof(struct sockaddr_in, sin_addr)},
     82 	{0, 0, 0},
     83 };
     84 
     85 struct sockinet {
     86 	u_char	si_len;
     87 	u_char	si_family;
     88 	u_short	si_port;
     89 };
     90 
     91 #define ENI_NOSOCKET 	0
     92 #define ENI_NOSERVNAME	1
     93 #define ENI_NOHOSTNAME	2
     94 #define ENI_MEMORY	3
     95 #define ENI_SYSTEM	4
     96 #define ENI_FAMILY	5
     97 #define ENI_SALEN	6
     98 
     99 int
    100 getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
    101 	const struct sockaddr *sa;
    102 	size_t salen;
    103 	char *host;
    104 	size_t hostlen;
    105 	char *serv;
    106 	size_t servlen;
    107 	int flags;
    108 {
    109 	struct afd *afd;
    110 	struct servent *sp;
    111 	struct hostent *hp;
    112 	u_short port;
    113 	int family, i;
    114 	char *addr, *p;
    115 	u_int32_t v4a;
    116 	int h_error;
    117 	char numserv[512];
    118 	char numaddr[512];
    119 
    120 	if (sa == NULL)
    121 		return ENI_NOSOCKET;
    122 
    123 #ifdef HAVE_SA_LEN	/*XXX*/
    124 	if (sa->sa_len != salen)
    125 		return ENI_SALEN;
    126 #endif
    127 
    128 	family = sa->sa_family;
    129 	for (i = 0; afdl[i].a_af; i++)
    130 		if (afdl[i].a_af == family) {
    131 			afd = &afdl[i];
    132 			goto found;
    133 		}
    134 	return ENI_FAMILY;
    135 
    136  found:
    137 	if (salen != afd->a_socklen)
    138 		return ENI_SALEN;
    139 
    140 	port = ((struct sockinet *)sa)->si_port; /* network byte order */
    141 	addr = (char *)sa + afd->a_off;
    142 
    143 	if (serv == NULL || servlen == 0) {
    144 		/*
    145 		 * do nothing in this case.
    146 		 * in case you are wondering if "&&" is more correct than
    147 		 * "||" here: RFC2553 says that serv == NULL OR servlen == 0
    148 		 * means that the caller does not want the result.
    149 		 */
    150 	} else {
    151 		if (flags & NI_NUMERICSERV)
    152 			sp = NULL;
    153 		else {
    154 			sp = getservbyport(port,
    155 				(flags & NI_DGRAM) ? "udp" : "tcp");
    156 		}
    157 		if (sp) {
    158 			if (strlen(sp->s_name) + 1 > servlen)
    159 				return ENI_MEMORY;
    160 			strcpy(serv, sp->s_name);
    161 		} else {
    162 			snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
    163 			if (strlen(numserv) + 1 > servlen)
    164 				return ENI_MEMORY;
    165 			strcpy(serv, numserv);
    166 		}
    167 	}
    168 
    169 	switch (sa->sa_family) {
    170 	case AF_INET:
    171 		v4a = (u_int32_t)
    172 			ntohl(((struct sockaddr_in *)sa)->sin_addr.s_addr);
    173 		if (IN_MULTICAST(v4a) || IN_EXPERIMENTAL(v4a))
    174 			flags |= NI_NUMERICHOST;
    175 		v4a >>= IN_CLASSA_NSHIFT;
    176 		if (v4a == 0)
    177 			flags |= NI_NUMERICHOST;
    178 		break;
    179 #ifdef INET6
    180 	case AF_INET6:
    181 	    {
    182 		struct sockaddr_in6 *sin6;
    183 		sin6 = (struct sockaddr_in6 *)sa;
    184 		switch (sin6->sin6_addr.s6_addr[0]) {
    185 		case 0x00:
    186 			if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
    187 				;
    188 			else if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
    189 				;
    190 			else
    191 				flags |= NI_NUMERICHOST;
    192 			break;
    193 		default:
    194 			if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    195 				flags |= NI_NUMERICHOST;
    196 			}
    197 			else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
    198 				flags |= NI_NUMERICHOST;
    199 			break;
    200 		}
    201 	    }
    202 		break;
    203 #endif
    204 	}
    205 	if (host == NULL || hostlen == 0) {
    206 		/*
    207 		 * do nothing in this case.
    208 		 * in case you are wondering if "&&" is more correct than
    209 		 * "||" here: RFC2553 says that host == NULL OR hostlen == 0
    210 		 * means that the caller does not want the result.
    211 		 */
    212 	} else if (flags & NI_NUMERICHOST) {
    213 		/* NUMERICHOST and NAMEREQD conflicts with each other */
    214 		if (flags & NI_NAMEREQD)
    215 			return ENI_NOHOSTNAME;
    216 		if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
    217 		    == NULL)
    218 			return ENI_SYSTEM;
    219 		if (strlen(numaddr) + 1 > hostlen)
    220 			return ENI_MEMORY;
    221 		strcpy(host, numaddr);
    222 #if defined(INET6) && defined(NI_WITHSCOPEID)
    223 		if (afd->a_af == AF_INET6 &&
    224 		    (IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)addr) ||
    225 		     IN6_IS_ADDR_MULTICAST((struct in6_addr *)addr)) &&
    226 		    ((struct sockaddr_in6 *)sa)->sin6_scope_id) {
    227 #ifndef ALWAYS_WITHSCOPE
    228 			if (flags & NI_WITHSCOPEID)
    229 #endif /* !ALWAYS_WITHSCOPE */
    230 			{
    231 				char *ep = strchr(host, '\0');
    232 				unsigned int ifindex =
    233 					((struct sockaddr_in6 *)sa)->sin6_scope_id;
    234 
    235 				*ep = SCOPE_DELIMITER;
    236 				if ((if_indextoname(ifindex, ep + 1)) == NULL)
    237 					/* XXX what should we do? */
    238 					strncpy(ep + 1, "???", 3);
    239 			}
    240 		}
    241 #endif /* INET6 */
    242 	} else {
    243 #ifdef USE_GETIPNODEBY
    244 		hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
    245 #else
    246 		hp = gethostbyaddr(addr, afd->a_addrlen, afd->a_af);
    247 #ifdef HAVE_H_ERRNO
    248 		h_error = h_errno;
    249 #else
    250 		h_error = EINVAL;
    251 #endif
    252 #endif
    253 
    254 		if (hp) {
    255 			if (flags & NI_NOFQDN) {
    256 				p = strchr(hp->h_name, '.');
    257 				if (p) *p = '\0';
    258 			}
    259 			if (strlen(hp->h_name) + 1 > hostlen) {
    260 #ifdef USE_GETIPNODEBY
    261 				freehostent(hp);
    262 #endif
    263 				return ENI_MEMORY;
    264 			}
    265 			strcpy(host, hp->h_name);
    266 #ifdef USE_GETIPNODEBY
    267 			freehostent(hp);
    268 #endif
    269 		} else {
    270 			if (flags & NI_NAMEREQD)
    271 				return ENI_NOHOSTNAME;
    272 			if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
    273 			    == NULL)
    274 				return ENI_NOHOSTNAME;
    275 			if (strlen(numaddr) + 1 > hostlen)
    276 				return ENI_MEMORY;
    277 			strcpy(host, numaddr);
    278 		}
    279 	}
    280 	return SUCCESS;
    281 }
    282