/* $NetBSD: res_init.c,v 1.36 2000/08/09 14:41:03 itojun Exp $ */ /*- * Copyright (c) 1985, 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * - * Portions Copyright (c) 1993 by Digital Equipment Corporation. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies, and that * the name of Digital Equipment Corporation not be used in advertising or * publicity pertaining to distribution of the document or software without * specific, written prior permission. * * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS * SOFTWARE. * - * --Copyright-- */ #include #if defined(LIBC_SCCS) && !defined(lint) #if 0 static char sccsid[] = "@(#)res_init.c 8.1 (Berkeley) 6/7/93"; static char rcsid[] = "Id: res_init.c,v 8.8 1997/06/01 20:34:37 vixie Exp "; #else __RCSID("$NetBSD: res_init.c,v 1.36 2000/08/09 14:41:03 itojun Exp $"); #endif #endif /* LIBC_SCCS and not lint */ #if defined(_LIBC) #include "namespace.h" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(_LIBC) && defined(__weak_alias) __weak_alias(res_init,_res_init) #endif static void res_setoptions __P((char *, char *)); static u_int32_t net_mask __P((struct in_addr)); static const char sort_mask[] = "/&"; #define ISSORTMASK(ch) (strchr(sort_mask, ch) != NULL) /* * Resolver state default settings */ /* #define __RES_IN_BSS */ #ifdef __RES_IN_BSS struct __res_state _res; #else struct __res_state _res = { RES_TIMEOUT, /* retransmition time interval */ 4, /* number of times to retransmit */ RES_DEFAULT, /* options flags */ 1, /* number of name servers */ }; #endif #ifdef INET6 struct __res_state_ext _res_ext; #endif /* INET6 */ /* * Set up default settings. If the configuration file exist, the values * there will have precedence. Otherwise, the server address is set to * INADDR_ANY and the default domain name comes from the gethostname(). * * An interrim version of this code (BIND 4.9, pre-4.4BSD) used 127.0.0.1 * rather than INADDR_ANY ("0.0.0.0") as the default name server address * since it was noted that INADDR_ANY actually meant ``the first interface * you "ifconfig"'d at boot time'' and if this was a SLIP or PPP interface, * it had to be "up" in order for you to reach your own name server. It * was later decided that since the recommended practice is to always * install local static routes through 127.0.0.1 for all your network * interfaces, that we could solve this problem without a code change. * * The configuration file should always be used, since it is the only way * to specify a default domain. If you are running a server on your local * machine, you should say "nameserver 0.0.0.0" or "nameserver 127.0.0.1" * in the configuration file. * * Return 0 if completes successfully, -1 on error */ int res_init() { register FILE *fp; register char *cp, **pp; register int n; char buf[MAXDNAME]; int nserv = 0; /* number of nameserver records read from file */ int haveenv = 0; int havesearch = 0; int nsort = 0; char *net; #ifndef RFC1535 int dots; #endif #ifdef __RES_IN_BSS /* * These three fields used to be statically initialized. This made * it hard to use this code in a shared library. It is necessary, * now that we're doing dynamic initialization here, that we preserve * the old semantics: if an application modifies one of these three * fields of _res before res_init() is called, res_init() will not * alter them. Of course, if an application is setting them to * _zero_ before calling res_init(), hoping to override what used * to be the static default, we can't detect it and unexpected results * will follow. Zero for any of these fields would make no sense, * so one can safely assume that the applications were already getting * unexpected results. * * _res.options is tricky since some apps were known to diddle the bits * before res_init() was first called. We can't replicate that semantic * with dynamic initialization (they may have turned bits off that are * set in RES_DEFAULT). Our solution is to declare such applications * "broken". They could fool us by setting RES_INIT but none do (yet). */ if (!_res.retrans) _res.retrans = RES_TIMEOUT; if (!_res.retry) _res.retry = 4; if (!(_res.options & RES_INIT)) _res.options = RES_DEFAULT; /* * This one used to initialize implicitly to zero, so unless the app * has set it to something in particular, we can randomize it now. */ if (!_res.id) _res.id = res_randomid(); #else _res.id = res_randomid(); #endif #ifdef USELOOPBACK _res.nsaddr.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1); #else _res.nsaddr.sin_addr.s_addr = INADDR_ANY; #endif _res.nsaddr.sin_family = AF_INET; _res.nsaddr.sin_port = htons(NAMESERVER_PORT); _res.nsaddr.sin_len = sizeof(struct sockaddr_in); #ifdef INET6 if (sizeof(_res_ext.nsaddr) >= _res.nsaddr.sin_len) memcpy(&_res_ext.nsaddr, &_res.nsaddr, (size_t)_res.nsaddr.sin_len); #endif _res.nscount = 1; _res.ndots = 1; _res.pfcode = 0; /* Allow user to override the local domain definition */ if ((cp = getenv("LOCALDOMAIN")) != NULL) { (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1); _res.defdname[sizeof(_res.defdname) - 1] = '\0'; if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL) *cp = '\0'; haveenv++; /* * Set search list to be blank-separated strings * from rest of env value. Permits users of LOCALDOMAIN * to still have a search list, and anyone to set the * one that they want to use as an individual (even more * important now that the rfc1535 stuff restricts searches) */ cp = _res.defdname; pp = _res.dnsrch; *pp++ = cp; for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) { if (*cp == '\n') /* silly backwards compat */ break; else if (*cp == ' ' || *cp == '\t') { *cp = 0; n = 1; } else if (n) { *pp++ = cp; n = 0; havesearch = 1; } } /* null terminate last domain if there are excess */ while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n') cp++; *cp = '\0'; *pp++ = 0; } #define MATCH(line, name) \ (!strncmp(line, name, sizeof(name) - 1) && \ (line[sizeof(name) - 1] == ' ' || \ line[sizeof(name) - 1] == '\t')) if ((fp = fopen(_PATH_RESCONF, "r")) != NULL) { /* read the config file */ while (fgets(buf, sizeof(buf), fp) != NULL) { /* skip comments */ if ((*buf == ';') || (*buf == '#')) continue; /* read default domain name */ if (MATCH(buf, "domain")) { if (haveenv) /* skip if have from environ */ continue; cp = buf + sizeof("domain") - 1; while (*cp == ' ' || *cp == '\t') cp++; if ((*cp == '\0') || (*cp == '\n')) continue; (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1); _res.defdname[sizeof(_res.defdname) - 1] = '\0'; if ((cp = strpbrk(_res.defdname, " \t\n")) != NULL) *cp = '\0'; havesearch = 0; continue; } /* lookup types; deprecated in favour of nsswitch.conf(5) */ if (MATCH(buf, "lookup")) continue; /* set search list */ if (MATCH(buf, "search")) { if (haveenv) /* skip if have from environ */ continue; cp = buf + sizeof("search") - 1; while (*cp == ' ' || *cp == '\t') cp++; if ((*cp == '\0') || (*cp == '\n')) continue; (void)strncpy(_res.defdname, cp, sizeof(_res.defdname) - 1); _res.defdname[sizeof(_res.defdname) - 1] = '\0'; if ((cp = strchr(_res.defdname, '\n')) != NULL) *cp = '\0'; /* * Set search list to be blank-separated strings * on rest of line. */ cp = _res.defdname; pp = _res.dnsrch; *pp++ = cp; for (n = 0; *cp && pp < _res.dnsrch + MAXDNSRCH; cp++) { if (*cp == ' ' || *cp == '\t') { *cp = 0; n = 1; } else if (n) { *pp++ = cp; n = 0; } } /* null terminate last domain if there are excess */ while (*cp != '\0' && *cp != ' ' && *cp != '\t') cp++; *cp = '\0'; *pp++ = 0; havesearch = 1; continue; } /* read nameservers to query */ if (MATCH(buf, "nameserver") && nserv < MAXNS) { struct addrinfo hints, *res; char pbuf[NI_MAXSERV]; char *q; #ifdef INET6 const size_t minsiz = sizeof(_res_ext.nsaddr_list[0]); #else const size_t minsiz = sizeof(_res.nsaddr_list[0]); #endif cp = buf + sizeof("nameserver") - 1; while (*cp == ' ' || *cp == '\t') cp++; if ((*cp == '\0') || (*cp == '\n')) continue; for (q = cp; *q; q++) { if (isspace((u_char) *q)) { *q = '\0'; break; } } memset(&hints, 0, sizeof(hints)); hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; hints.ai_flags = AI_NUMERICHOST; snprintf(pbuf, sizeof(pbuf), "%d", NAMESERVER_PORT); res = NULL; if (getaddrinfo(cp, pbuf, &hints, &res) == 0 && minsiz >= res->ai_addrlen) { memset(&_res.nsaddr_list[nserv], 0, sizeof(_res.nsaddr_list[nserv])); #ifdef INET6 /* * we copy the address to _res.nsaddr_list for * backward compatibility only. */ #endif if (sizeof(_res.nsaddr_list[nserv]) >= res->ai_addrlen) { memcpy(&_res.nsaddr_list[nserv], res->ai_addr, res->ai_addrlen); } #ifdef INET6 memset(&_res_ext.nsaddr_list[nserv], 0, sizeof(_res_ext.nsaddr_list[nserv])); memcpy(&_res_ext.nsaddr_list[nserv], res->ai_addr, res->ai_addrlen); #endif nserv++; } if (res) freeaddrinfo(res); continue; } if (MATCH(buf, "sortlist")) { struct in_addr a; #ifdef INET6 struct in6_addr a6; int m, i; u_char *u; #endif /* INET6 */ cp = buf + sizeof("sortlist") - 1; while (nsort < MAXRESOLVSORT) { while (*cp == ' ' || *cp == '\t') cp++; if (*cp == '\0' || *cp == '\n' || *cp == ';') break; net = cp; while (*cp && !ISSORTMASK(*cp) && *cp != ';' && isascii(*cp) && !isspace((u_char) *cp)) cp++; n = *cp; *cp = 0; if (inet_aton(net, &a)) { _res.sort_list[nsort].addr = a; if (ISSORTMASK(n)) { *cp++ = n; net = cp; while (*cp && *cp != ';' && isascii(*cp) && !isspace((u_char) *cp)) cp++; n = *cp; *cp = 0; if (inet_aton(net, &a)) { _res.sort_list[nsort].mask = a.s_addr; } else { _res.sort_list[nsort].mask = net_mask(_res.sort_list[nsort].addr); } } else { _res.sort_list[nsort].mask = net_mask(_res.sort_list[nsort].addr); } #ifdef INET6 _res_ext.sort_list[nsort].af = AF_INET; _res_ext.sort_list[nsort].addr.ina = _res.sort_list[nsort].addr; _res_ext.sort_list[nsort].mask.ina.s_addr = _res.sort_list[nsort].mask; #endif /* INET6 */ nsort++; } #ifdef INET6 else if (inet_pton(AF_INET6, net, &a6) == 1) { _res_ext.sort_list[nsort].af = AF_INET6; _res_ext.sort_list[nsort].addr.in6a = a6; u = (u_char *)(void *) &_res_ext.sort_list[nsort].mask.in6a; *cp++ = n; net = cp; while (*cp && *cp != ';' && isascii(*cp) && !isspace((u_char) *cp)) cp++; m = n; n = *cp; *cp = 0; switch (m) { case '/': m = atoi(net); break; case '&': if (inet_pton(AF_INET6, net, u) == 1) { m = -1; break; } /*FALLTHRU*/ default: m = sizeof(struct in6_addr) * NBBY; break; } if (m >= 0) { for (i = 0; i < sizeof(struct in6_addr); i++) { if (m <= 0) { *u = 0; } else { m -= NBBY; *u = (u_char)~0; if (m < 0) *u <<= -m; } u++; } } nsort++; } #endif /* INET6 */ *cp = n; } continue; } if (MATCH(buf, "options")) { res_setoptions(buf + sizeof("options") - 1, "conf"); continue; } } if (nserv > 1) _res.nscount = nserv; _res.nsort = nsort; (void) fclose(fp); } if (_res.defdname[0] == 0) { int rv; rv = gethostname(buf, sizeof(_res.defdname)); _res.defdname[sizeof(_res.defdname) - 1] = '\0'; if (rv == 0 && (cp = strchr(buf, '.'))) (void)strncpy(_res.defdname, cp + 1, sizeof(_res.defdname) - 1); } /* find components of local domain that might be searched */ if (havesearch == 0) { pp = _res.dnsrch; *pp++ = _res.defdname; *pp = NULL; #ifndef RFC1535 dots = 0; for (cp = _res.defdname; *cp; cp++) dots += (*cp == '.'); cp = _res.defdname; while (pp < _res.dnsrch + MAXDFLSRCH) { if (dots < LOCALDOMAINPARTS) break; cp = strchr(cp, '.') + 1; /* we know there is one */ *pp++ = cp; dots--; } *pp = NULL; #ifdef DEBUG if (_res.options & RES_DEBUG) { printf(";; res_init()... default dnsrch list:\n"); for (pp = _res.dnsrch; *pp; pp++) printf(";;\t%s\n", *pp); printf(";;\t..END..\n"); } #endif /* DEBUG */ #endif /* !RFC1535 */ } if ((cp = getenv("RES_OPTIONS")) != NULL) res_setoptions(cp, "env"); _res.options |= RES_INIT; return (0); } /* ARGSUSED */ static void res_setoptions(options, source) char *options, *source; { char *cp = options; int i; _DIAGASSERT(options != NULL); _DIAGASSERT(source != NULL); #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";; res_setoptions(\"%s\", \"%s\")...\n", options, source); #endif while (*cp) { /* skip leading and inner runs of spaces */ while (*cp == ' ' || *cp == '\t') cp++; /* search for and process individual options */ if (!strncmp(cp, "ndots:", sizeof("ndots:") - 1)) { i = atoi(cp + sizeof("ndots:") - 1); if (i <= RES_MAXNDOTS) _res.ndots = i; else _res.ndots = RES_MAXNDOTS; #ifdef DEBUG if (_res.options & RES_DEBUG) printf(";;\tndots=%d\n", _res.ndots); #endif } else if (!strncmp(cp, "debug", sizeof("debug") - 1)) { #ifdef DEBUG if (!(_res.options & RES_DEBUG)) { printf(";; res_setoptions(\"%s\", \"%s\")..\n", options, source); _res.options |= RES_DEBUG; } printf(";;\tdebug\n"); #endif } else if (!strncmp(cp, "inet6", sizeof("inet6") - 1)) { _res.options |= RES_USE_INET6; } #ifdef RES_USE_EDNS0 else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) { _res.options |= RES_USE_EDNS0; } #endif else { /* XXX - print a warning here? */ } /* skip to next run of spaces */ while (*cp && *cp != ' ' && *cp != '\t') cp++; } } /* XXX - should really support CIDR which means explicit masks always. */ static u_int32_t net_mask(in) /* XXX - should really use system's version of this */ struct in_addr in; { register u_int32_t i = ntohl(in.s_addr); if (IN_CLASSA(i)) return (htonl(IN_CLASSA_NET)); else if (IN_CLASSB(i)) return (htonl(IN_CLASSB_NET)); return (htonl(IN_CLASSC_NET)); } u_int res_randomid() { struct timeval now; gettimeofday(&now, NULL); return (u_int)(0xffff & (now.tv_sec ^ now.tv_usec ^ getpid())); }