/* $NetBSD: gethnamaddr.c,v 1.70 2006/03/22 00:03:51 christos Exp $ */ /* * ++Copyright++ 1985, 1988, 1993 * - * Copyright (c) 1985, 1988, 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. 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 #include #include #include #include #include #include #include #include "resolv_netid.h" #include "resolv_private.h" #include "resolv_cache.h" #include #include #include #include #include #include #include #include #include #define ALIGNBYTES (sizeof(uintptr_t) - 1) #define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) &~ ALIGNBYTES) #ifndef LOG_AUTH # define LOG_AUTH 0 #endif #define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */ #include "nsswitch.h" #include #include // This should be synchronized to ResponseCode.h static const int DnsProxyQueryResult = 222; static const char const AskedForGot[] = "gethostby*.getanswer: asked for \"%s\", got \"%s\""; #define MAXPACKET (64*1024) typedef union { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; typedef union { int32_t al; char ac; } align; #ifdef DEBUG static void dprintf(const char *, res_state, ...) __attribute__((__format__(__printf__, 1, 3))); #endif static struct hostent *getanswer(const querybuf *, int, const char *, int, res_state); static void map_v4v6_address(const char *, char *); static void map_v4v6_hostent(struct hostent *, char **, char *); static void addrsort(char **, int, res_state); static void _sethtent(int); static void _endhtent(void); static struct hostent *_gethtent(void); void ht_sethostent(int); void ht_endhostent(void); struct hostent *ht_gethostbyname(char *); struct hostent *ht_gethostbyaddr(const char *, int, int); void dns_service(void); #undef dn_skipname int dn_skipname(const u_char *, const u_char *); static int _gethtbyaddr(void *, void *, va_list); static int _gethtbyname(void *, void *, va_list); static struct hostent *_gethtbyname2(const char *, int); static int _dns_gethtbyaddr(void *, void *, va_list); static int _dns_gethtbyname(void *, void *, va_list); static struct hostent *gethostbyname_internal(const char *, int, res_state, unsigned, unsigned); static const ns_src default_dns_files[] = { { NSSRC_FILES, NS_SUCCESS }, { NSSRC_DNS, NS_SUCCESS }, { 0, 0 } }; #ifdef DEBUG static void dprintf(const char *msg, res_state res, ...) { assert(msg != NULL); if (res->options & RES_DEBUG) { int save = errno; va_list ap; va_start (ap, res); vprintf(msg, ap); va_end (ap); errno = save; } } #else # define dprintf(msg, res, num) ((void)0) /*nada*/ #endif #define BOUNDED_INCR(x) \ do { \ cp += (x); \ if (cp > eom) { \ h_errno = NO_RECOVERY; \ return NULL; \ } \ } while (/*CONSTCOND*/0) #define BOUNDS_CHECK(ptr, count) \ do { \ if ((ptr) + (count) > eom) { \ h_errno = NO_RECOVERY; \ return NULL; \ } \ } while (/*CONSTCOND*/0) static struct hostent * getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, res_state res) { const HEADER *hp; const u_char *cp; int n; const u_char *eom, *erdata; char *bp, **ap, **hap, *ep; int type, class, ancount, qdcount; int haveanswer, had_error; int toobig = 0; char tbuf[MAXDNAME]; const char *tname; int (*name_ok)(const char *); res_static rs = __res_get_static(); assert(answer != NULL); assert(qname != NULL); tname = qname; rs->host.h_name = NULL; eom = answer->buf + anslen; switch (qtype) { case T_A: case T_AAAA: name_ok = res_hnok; break; case T_PTR: name_ok = res_dnok; break; default: return NULL; /* XXX should be abort(); */ } /* * find first satisfactory answer */ hp = &answer->hdr; ancount = ntohs(hp->ancount); qdcount = ntohs(hp->qdcount); bp = rs->hostbuf; ep = rs->hostbuf + sizeof rs->hostbuf; cp = answer->buf; BOUNDED_INCR(HFIXEDSZ); if (qdcount != 1) { h_errno = NO_RECOVERY; return NULL; } n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !(*name_ok)(bp)) { h_errno = NO_RECOVERY; return NULL; } BOUNDED_INCR(n + QFIXEDSZ); if (qtype == T_A || qtype == T_AAAA) { /* res_send() has already verified that the query name is the * same as the one we sent; this just gets the expanded name * (i.e., with the succeeding search-domain tacked on). */ n = strlen(bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { h_errno = NO_RECOVERY; return NULL; } rs->host.h_name = bp; bp += n; /* The qname can be abbreviated, but h_name is now absolute. */ qname = rs->host.h_name; } ap = rs->host_aliases; *ap = NULL; rs->host.h_aliases = rs->host_aliases; hap = rs->h_addr_ptrs; *hap = NULL; rs->host.h_addr_list = rs->h_addr_ptrs; haveanswer = 0; had_error = 0; while (ancount-- > 0 && cp < eom && !had_error) { n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !(*name_ok)(bp)) { had_error++; continue; } cp += n; /* name */ BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ); type = _getshort(cp); cp += INT16SZ; /* type */ class = _getshort(cp); cp += INT16SZ + INT32SZ; /* class, TTL */ n = _getshort(cp); cp += INT16SZ; /* len */ BOUNDS_CHECK(cp, n); erdata = cp + n; if (class != C_IN) { /* XXX - debug? syslog? */ cp += n; continue; /* XXX - had_error++ ? */ } if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) { if (ap >= &rs->host_aliases[MAXALIASES-1]) continue; n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); if ((n < 0) || !(*name_ok)(tbuf)) { had_error++; continue; } cp += n; if (cp != erdata) { h_errno = NO_RECOVERY; return NULL; } /* Store alias. */ *ap++ = bp; n = strlen(bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { had_error++; continue; } bp += n; /* Get canonical name. */ n = strlen(tbuf) + 1; /* for the \0 */ if (n > ep - bp || n >= MAXHOSTNAMELEN) { had_error++; continue; } strlcpy(bp, tbuf, (size_t)(ep - bp)); rs->host.h_name = bp; bp += n; continue; } if (qtype == T_PTR && type == T_CNAME) { n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf); if (n < 0 || !res_dnok(tbuf)) { had_error++; continue; } cp += n; if (cp != erdata) { h_errno = NO_RECOVERY; return NULL; } /* Get canonical name. */ n = strlen(tbuf) + 1; /* for the \0 */ if (n > ep - bp || n >= MAXHOSTNAMELEN) { had_error++; continue; } strlcpy(bp, tbuf, (size_t)(ep - bp)); tname = bp; bp += n; continue; } if (type != qtype) { if (type != T_KEY && type != T_SIG) syslog(LOG_NOTICE|LOG_AUTH, "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", qname, p_class(C_IN), p_type(qtype), p_type(type)); cp += n; continue; /* XXX - had_error++ ? */ } switch (type) { case T_PTR: if (strcasecmp(tname, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, qname, bp); cp += n; continue; /* XXX - had_error++ ? */ } n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !res_hnok(bp)) { had_error++; break; } #if MULTI_PTRS_ARE_ALIASES cp += n; if (cp != erdata) { h_errno = NO_RECOVERY; return NULL; } if (!haveanswer) rs->host.h_name = bp; else if (ap < &rs->host_aliases[MAXALIASES-1]) *ap++ = bp; else n = -1; if (n != -1) { n = strlen(bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { had_error++; break; } bp += n; } break; #else rs->host.h_name = bp; if (res->options & RES_USE_INET6) { n = strlen(bp) + 1; /* for the \0 */ if (n >= MAXHOSTNAMELEN) { had_error++; break; } bp += n; map_v4v6_hostent(&rs->host, &bp, ep); } h_errno = NETDB_SUCCESS; return &rs->host; #endif case T_A: case T_AAAA: if (strcasecmp(rs->host.h_name, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, rs->host.h_name, bp); cp += n; continue; /* XXX - had_error++ ? */ } if (n != rs->host.h_length) { cp += n; continue; } if (type == T_AAAA) { struct in6_addr in6; memcpy(&in6, cp, IN6ADDRSZ); if (IN6_IS_ADDR_V4MAPPED(&in6)) { cp += n; continue; } } if (!haveanswer) { int nn; rs->host.h_name = bp; nn = strlen(bp) + 1; /* for the \0 */ bp += nn; } bp += sizeof(align) - (size_t)((u_long)bp % sizeof(align)); if (bp + n >= &rs->hostbuf[sizeof rs->hostbuf]) { dprintf("size (%d) too big\n", res, n); had_error++; continue; } if (hap >= &rs->h_addr_ptrs[MAXADDRS-1]) { if (!toobig++) dprintf("Too many addresses (%d)\n", res, MAXADDRS); cp += n; continue; } (void)memcpy(*hap++ = bp, cp, (size_t)n); bp += n; cp += n; if (cp != erdata) { h_errno = NO_RECOVERY; return NULL; } break; default: abort(); } if (!had_error) haveanswer++; } if (haveanswer) { *ap = NULL; *hap = NULL; /* * Note: we sort even if host can take only one address * in its return structures - should give it the "best" * address in that case, not some random one */ if (res->nsort && haveanswer > 1 && qtype == T_A) addrsort(rs->h_addr_ptrs, haveanswer, res); if (!rs->host.h_name) { n = strlen(qname) + 1; /* for the \0 */ if (n > ep - bp || n >= MAXHOSTNAMELEN) goto no_recovery; strlcpy(bp, qname, (size_t)(ep - bp)); rs->host.h_name = bp; bp += n; } if (res->options & RES_USE_INET6) map_v4v6_hostent(&rs->host, &bp, ep); h_errno = NETDB_SUCCESS; return &rs->host; } no_recovery: h_errno = NO_RECOVERY; return NULL; } int gethostbyname_r(const char *name, struct hostent *hp, char *buf, size_t buflen, struct hostent**result, int *errorp) { struct hostent *res; res = gethostbyname(name); *errorp = h_errno; if (res == NULL) { *result = NULL; return -1; } memcpy(hp, res, sizeof *hp); *result = hp; return 0; } struct hostent * gethostbyname(const char *name) { struct hostent *hp; res_state res = __res_get_state(); if (res == NULL) return NULL; assert(name != NULL); /* try IPv6 first - if that fails do IPv4 */ if (res->options & RES_USE_INET6) { hp = gethostbyname_internal(name, AF_INET6, res, NETID_UNSET, MARK_UNSET); if (hp) { __res_put_state(res); return hp; } } hp = gethostbyname_internal(name, AF_INET, res, NETID_UNSET, MARK_UNSET); __res_put_state(res); return hp; } struct hostent * gethostbyname2(const char *name, int af) { return android_gethostbynamefornet(name, af, NETID_UNSET, MARK_UNSET); } struct hostent * android_gethostbynamefornet(const char *name, int af, unsigned netid, unsigned mark) { struct hostent *hp; res_state res = __res_get_state(); if (res == NULL) return NULL; hp = gethostbyname_internal(name, af, res, netid, mark); __res_put_state(res); return hp; } static FILE* android_open_proxy() { int sock; const int one = 1; struct sockaddr_un proxy_addr; sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) { return NULL; } setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); memset(&proxy_addr, 0, sizeof(proxy_addr)); proxy_addr.sun_family = AF_UNIX; strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path)); if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) &proxy_addr, sizeof(proxy_addr))) != 0) { close(sock); return NULL; } return fdopen(sock, "r+"); } static struct hostent * android_read_hostent(FILE* proxy) { uint32_t size; char buf[4]; if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) return NULL; /* This is reading serialized data from system/netd/DnsProxyListener.cpp * and changes here need to be matched there */ int result_code = strtol(buf, NULL, 10); if (result_code != DnsProxyQueryResult) { fread(&size, 1, sizeof(size), proxy); return NULL; } if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL; size = ntohl(size); res_static rs = __res_get_static(); memset(&rs->host, 0, sizeof(rs->host)); char *ptr = rs->hostbuf; if (fread(ptr, 1, size, proxy) != size) return NULL; ptr += size; rs->host.h_name = rs->hostbuf; char **aliases = rs->host_aliases; rs->host.h_aliases = rs->host_aliases; while (1) { if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL; size = ntohl(size); if (size == 0) { *aliases = NULL; break; } if (fread(ptr, 1, size, proxy) != size) return NULL; *aliases++ = ptr; ptr += size; } if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL; rs->host.h_addrtype = ntohl(size); if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL; rs->host.h_length = ntohl(size); char **addrs = rs->h_addr_ptrs; rs->host.h_addr_list = rs->h_addr_ptrs; while (1) { if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL; size = ntohl(size); if (size == 0) { *addrs = NULL; break; } if (fread(ptr, 1, size, proxy) != size) return NULL; *addrs++ = ptr; ptr += size; } return &rs->host; } static struct hostent * gethostbyname_internal_real(const char *name, int af, res_state res) { const char *cp; char *bp, *ep; int size; struct hostent *hp; res_static rs = __res_get_static(); static const ns_dtab dtab[] = { NS_FILES_CB(_gethtbyname, NULL) { NSSRC_DNS, _dns_gethtbyname, NULL }, /* force -DHESIOD */ { 0, 0, 0 } }; assert(name != NULL); switch (af) { case AF_INET: size = INADDRSZ; break; case AF_INET6: size = IN6ADDRSZ; break; default: h_errno = NETDB_INTERNAL; errno = EAFNOSUPPORT; return NULL; } rs->host.h_addrtype = af; rs->host.h_length = size; /* * if there aren't any dots, it could be a user-level alias. * this is also done in res_nquery() since we are not the only * function that looks up host names. */ if (!strchr(name, '.') && (cp = __hostalias(name))) name = cp; /* * disallow names consisting only of digits/dots, unless * they end in a dot. */ if (isdigit((u_char) name[0])) for (cp = name;; ++cp) { if (!*cp) { if (*--cp == '.') break; /* * All-numeric, no dot at the end. * Fake up a hostent as if we'd actually * done a lookup. */ if (inet_pton(af, name, (char *)(void *)rs->host_addr) <= 0) { h_errno = HOST_NOT_FOUND; return NULL; } strncpy(rs->hostbuf, name, MAXDNAME); rs->hostbuf[MAXDNAME] = '\0'; bp = rs->hostbuf + MAXDNAME; ep = rs->hostbuf + sizeof rs->hostbuf; rs->host.h_name = rs->hostbuf; rs->host.h_aliases = rs->host_aliases; rs->host_aliases[0] = NULL; rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr; rs->h_addr_ptrs[1] = NULL; rs->host.h_addr_list = rs->h_addr_ptrs; if (res->options & RES_USE_INET6) map_v4v6_hostent(&rs->host, &bp, ep); h_errno = NETDB_SUCCESS; return &rs->host; } if (!isdigit((u_char) *cp) && *cp != '.') break; } if ((isxdigit((u_char) name[0]) && strchr(name, ':') != NULL) || name[0] == ':') for (cp = name;; ++cp) { if (!*cp) { if (*--cp == '.') break; /* * All-IPv6-legal, no dot at the end. * Fake up a hostent as if we'd actually * done a lookup. */ if (inet_pton(af, name, (char *)(void *)rs->host_addr) <= 0) { h_errno = HOST_NOT_FOUND; return NULL; } strncpy(rs->hostbuf, name, MAXDNAME); rs->hostbuf[MAXDNAME] = '\0'; bp = rs->hostbuf + MAXDNAME; ep = rs->hostbuf + sizeof rs->hostbuf; rs->host.h_name = rs->hostbuf; rs->host.h_aliases = rs->host_aliases; rs->host_aliases[0] = NULL; rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr; rs->h_addr_ptrs[1] = NULL; rs->host.h_addr_list = rs->h_addr_ptrs; h_errno = NETDB_SUCCESS; return &rs->host; } if (!isxdigit((u_char) *cp) && *cp != ':' && *cp != '.') break; } hp = NULL; h_errno = NETDB_INTERNAL; if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyname", default_dns_files, name, strlen(name), af) != NS_SUCCESS) { return NULL; } h_errno = NETDB_SUCCESS; return hp; } // very similar in proxy-ness to android_getaddrinfo_proxy static struct hostent * gethostbyname_internal(const char *name, int af, res_state res, unsigned netid, unsigned mark) { const char *cache_mode = getenv("ANDROID_DNS_MODE"); FILE* proxy = NULL; struct hostent *result = NULL; if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { res_setnetid(res, netid); res_setmark(res, mark); return gethostbyname_internal_real(name, af, res); } proxy = android_open_proxy(); if (proxy == NULL) goto exit; /* This is writing to system/netd/DnsProxyListener.cpp and changes * here need to be matched there */ if (fprintf(proxy, "gethostbyname %u %s %d", netid, name == NULL ? "^" : name, af) < 0) { goto exit; } if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { goto exit; } result = android_read_hostent(proxy); exit: if (proxy != NULL) { fclose(proxy); } return result; } struct hostent * android_gethostbyaddrfornet_proxy(const void *addr, socklen_t len, int af, unsigned netid) { struct hostent *result = NULL; FILE* proxy = android_open_proxy(); if (proxy == NULL) goto exit; char buf[INET6_ADDRSTRLEN]; //big enough for IPv4 and IPv6 const char * addrStr = inet_ntop(af, addr, buf, sizeof(buf)); if (addrStr == NULL) goto exit; if (fprintf(proxy, "gethostbyaddr %s %d %d %u", addrStr, len, af, netid) < 0) { goto exit; } if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { goto exit; } result = android_read_hostent(proxy); exit: if (proxy != NULL) { fclose(proxy); } return result; } struct hostent * android_gethostbyaddrfornet_real(const void *addr, socklen_t len, int af, unsigned netid, unsigned mark) { const u_char *uaddr = (const u_char *)addr; socklen_t size; struct hostent *hp; static const ns_dtab dtab[] = { NS_FILES_CB(_gethtbyaddr, NULL) { NSSRC_DNS, _dns_gethtbyaddr, NULL }, /* force -DHESIOD */ { 0, 0, 0 } }; assert(addr != NULL); if (af == AF_INET6 && len == IN6ADDRSZ && (IN6_IS_ADDR_LINKLOCAL((const struct in6_addr *)(const void *)uaddr) || IN6_IS_ADDR_SITELOCAL((const struct in6_addr *)(const void *)uaddr))) { h_errno = HOST_NOT_FOUND; return NULL; } if (af == AF_INET6 && len == IN6ADDRSZ && (IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)(const void *)uaddr) || IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)(const void *)uaddr))) { /* Unmap. */ addr += IN6ADDRSZ - INADDRSZ; uaddr += IN6ADDRSZ - INADDRSZ; af = AF_INET; len = INADDRSZ; } switch (af) { case AF_INET: size = INADDRSZ; break; case AF_INET6: size = IN6ADDRSZ; break; default: errno = EAFNOSUPPORT; h_errno = NETDB_INTERNAL; return NULL; } if (size != len) { errno = EINVAL; h_errno = NETDB_INTERNAL; return NULL; } hp = NULL; h_errno = NETDB_INTERNAL; if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr", default_dns_files, uaddr, len, af, netid, mark) != NS_SUCCESS) return NULL; h_errno = NETDB_SUCCESS; return hp; } struct hostent * android_gethostbyaddrfornet(const void *addr, socklen_t len, int af, unsigned netid, unsigned mark) { const char *cache_mode = getenv("ANDROID_DNS_MODE"); if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) { return android_gethostbyaddrfornet_proxy(addr, len, af, netid); } else { return android_gethostbyaddrfornet_real(addr,len, af, netid, mark); } } struct hostent * gethostbyaddr(const void *addr, socklen_t len, int af) { return android_gethostbyaddrfornet(addr, len, af, NETID_UNSET, MARK_UNSET); } static void _sethtent(int f) { res_static rs = __res_get_static(); if (rs == NULL) return; if (!rs->hostf) rs->hostf = fopen(_PATH_HOSTS, "r" ); else rewind(rs->hostf); rs->stayopen = f; } static void _endhtent(void) { res_static rs = __res_get_static(); if (rs == NULL) return; if (rs->hostf && !rs->stayopen) { (void) fclose(rs->hostf); rs->hostf = NULL; } } static struct hostent * _gethtent(void) { char *p; char *cp, **q; int af, len; res_static rs = __res_get_static(); if (!rs->hostf && !(rs->hostf = fopen(_PATH_HOSTS, "r" ))) { h_errno = NETDB_INTERNAL; return NULL; } again: if (!(p = fgets(rs->hostbuf, sizeof rs->hostbuf, rs->hostf))) { h_errno = HOST_NOT_FOUND; return NULL; } if (*p == '#') goto again; if (!(cp = strpbrk(p, "#\n"))) goto again; *cp = '\0'; if (!(cp = strpbrk(p, " \t"))) goto again; *cp++ = '\0'; if (inet_pton(AF_INET6, p, (char *)(void *)rs->host_addr) > 0) { af = AF_INET6; len = IN6ADDRSZ; } else if (inet_pton(AF_INET, p, (char *)(void *)rs->host_addr) > 0) { res_state res = __res_get_state(); if (res == NULL) return NULL; if (res->options & RES_USE_INET6) { map_v4v6_address((char *)(void *)rs->host_addr, (char *)(void *)rs->host_addr); af = AF_INET6; len = IN6ADDRSZ; } else { af = AF_INET; len = INADDRSZ; } __res_put_state(res); } else { goto again; } /* if this is not something we're looking for, skip it. */ if (rs->host.h_addrtype != 0 && rs->host.h_addrtype != af) goto again; if (rs->host.h_length != 0 && rs->host.h_length != len) goto again; rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr; rs->h_addr_ptrs[1] = NULL; rs->host.h_addr_list = rs->h_addr_ptrs; rs->host.h_length = len; rs->host.h_addrtype = af; while (*cp == ' ' || *cp == '\t') cp++; rs->host.h_name = cp; q = rs->host.h_aliases = rs->host_aliases; if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0'; while (cp && *cp) { if (*cp == ' ' || *cp == '\t') { cp++; continue; } if (q < &rs->host_aliases[MAXALIASES - 1]) *q++ = cp; if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0'; } *q = NULL; h_errno = NETDB_SUCCESS; return &rs->host; } /*ARGSUSED*/ int _gethtbyname(void *rv, void *cb_data, va_list ap) { struct hostent *hp; const char *name; int af; assert(rv != NULL); name = va_arg(ap, char *); /* NOSTRICT skip len */(void)va_arg(ap, int); af = va_arg(ap, int); hp = NULL; #if 0 { res_state res = __res_get_state(); if (res == NULL) return NS_NOTFOUND; if (res->options & RES_USE_INET6) hp = _gethtbyname2(name, AF_INET6); if (hp==NULL) hp = _gethtbyname2(name, AF_INET); __res_put_state(res); } #else hp = _gethtbyname2(name, af); #endif *((struct hostent **)rv) = hp; if (hp == NULL) { h_errno = HOST_NOT_FOUND; return NS_NOTFOUND; } return NS_SUCCESS; } static struct hostent * _gethtbyname2(const char *name, int af) { struct hostent *p; char *tmpbuf, *ptr, **cp; int num; size_t len; res_static rs = __res_get_static(); assert(name != NULL); _sethtent(rs->stayopen); ptr = tmpbuf = NULL; num = 0; while ((p = _gethtent()) != NULL && num < MAXADDRS) { if (p->h_addrtype != af) continue; if (strcasecmp(p->h_name, name) != 0) { for (cp = p->h_aliases; *cp != NULL; cp++) if (strcasecmp(*cp, name) == 0) break; if (*cp == NULL) continue; } if (num == 0) { size_t bufsize; char *src; bufsize = strlen(p->h_name) + 2 + MAXADDRS * p->h_length + ALIGNBYTES; for (cp = p->h_aliases; *cp != NULL; cp++) bufsize += strlen(*cp) + 1; if ((tmpbuf = malloc(bufsize)) == NULL) { h_errno = NETDB_INTERNAL; return NULL; } ptr = tmpbuf; src = p->h_name; while ((*ptr++ = *src++) != '\0'); for (cp = p->h_aliases; *cp != NULL; cp++) { src = *cp; while ((*ptr++ = *src++) != '\0'); } *ptr++ = '\0'; ptr = (char *)(void *)ALIGN(ptr); } (void)memcpy(ptr, p->h_addr_list[0], (size_t)p->h_length); ptr += p->h_length; num++; } _endhtent(); if (num == 0) return NULL; len = ptr - tmpbuf; if (len > (sizeof(rs->hostbuf) - ALIGNBYTES)) { free(tmpbuf); errno = ENOSPC; h_errno = NETDB_INTERNAL; return NULL; } ptr = memcpy((void *)ALIGN(rs->hostbuf), tmpbuf, len); free(tmpbuf); rs->host.h_name = ptr; while (*ptr++); cp = rs->host_aliases; while (*ptr) { *cp++ = ptr; while (*ptr++); } ptr++; *cp = NULL; ptr = (char *)(void *)ALIGN(ptr); cp = rs->h_addr_ptrs; while (num--) { *cp++ = ptr; ptr += rs->host.h_length; } *cp = NULL; return &rs->host; } /*ARGSUSED*/ static int _gethtbyaddr(void *rv, void *cb_data, va_list ap) { struct hostent *p; const unsigned char *addr; int len, af; res_static rs = __res_get_static(); assert(rv != NULL); addr = va_arg(ap, unsigned char *); len = va_arg(ap, int); af = va_arg(ap, int); rs->host.h_length = len; rs->host.h_addrtype = af; _sethtent(rs->stayopen); while ((p = _gethtent()) != NULL) if (p->h_addrtype == af && !memcmp(p->h_addr, addr, (size_t)len)) break; _endhtent(); *((struct hostent **)rv) = p; if (p==NULL) { h_errno = HOST_NOT_FOUND; return NS_NOTFOUND; } return NS_SUCCESS; } static void map_v4v6_address(const char *src, char *dst) { u_char *p = (u_char *)dst; char tmp[INADDRSZ]; int i; assert(src != NULL); assert(dst != NULL); /* Stash a temporary copy so our caller can update in place. */ (void)memcpy(tmp, src, INADDRSZ); /* Mark this ipv6 addr as a mapped ipv4. */ for (i = 0; i < 10; i++) *p++ = 0x00; *p++ = 0xff; *p++ = 0xff; /* Retrieve the saved copy and we're done. */ (void)memcpy((void *)p, tmp, INADDRSZ); } static void map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep) { char **ap; assert(hp != NULL); assert(bpp != NULL); assert(ep != NULL); if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ) return; hp->h_addrtype = AF_INET6; hp->h_length = IN6ADDRSZ; for (ap = hp->h_addr_list; *ap; ap++) { int i = sizeof(align) - (size_t)((u_long)*bpp % sizeof(align)); if (ep - *bpp < (i + IN6ADDRSZ)) { /* Out of memory. Truncate address list here. XXX */ *ap = NULL; return; } *bpp += i; map_v4v6_address(*ap, *bpp); *ap = *bpp; *bpp += IN6ADDRSZ; } } static void addrsort(char **ap, int num, res_state res) { int i, j; char **p; short aval[MAXADDRS]; int needsort = 0; assert(ap != NULL); p = ap; for (i = 0; i < num; i++, p++) { for (j = 0 ; (unsigned)j < res->nsort; j++) if (res->sort_list[j].addr.s_addr == (((struct in_addr *)(void *)(*p))->s_addr & res->sort_list[j].mask)) break; aval[i] = j; if (needsort == 0 && i > 0 && j < aval[i-1]) needsort = i; } if (!needsort) return; while (needsort < num) { for (j = needsort - 1; j >= 0; j--) { if (aval[j] > aval[j+1]) { char *hp; i = aval[j]; aval[j] = aval[j+1]; aval[j+1] = i; hp = ap[j]; ap[j] = ap[j+1]; ap[j+1] = hp; } else break; } needsort++; } } struct hostent * gethostent(void) { res_static rs = __res_get_static(); rs->host.h_addrtype = 0; rs->host.h_length = 0; return _gethtent(); } /*ARGSUSED*/ static int _dns_gethtbyname(void *rv, void *cb_data, va_list ap) { querybuf *buf; int n, type; struct hostent *hp; const char *name; int af; res_state res; assert(rv != NULL); name = va_arg(ap, char *); /* NOSTRICT skip len */(void)va_arg(ap, int); af = va_arg(ap, int); switch (af) { case AF_INET: type = T_A; break; case AF_INET6: type = T_AAAA; break; default: return NS_UNAVAIL; } buf = malloc(sizeof(*buf)); if (buf == NULL) { h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } res = __res_get_state(); if (res == NULL) { free(buf); return NS_NOTFOUND; } n = res_nsearch(res, name, C_IN, type, buf->buf, sizeof(buf->buf)); if (n < 0) { free(buf); dprintf("res_nsearch failed (%d)\n", res, n); __res_put_state(res); return NS_NOTFOUND; } hp = getanswer(buf, n, name, type, res); free(buf); __res_put_state(res); if (hp == NULL) switch (h_errno) { case HOST_NOT_FOUND: return NS_NOTFOUND; case TRY_AGAIN: return NS_TRYAGAIN; default: return NS_UNAVAIL; } *((struct hostent **)rv) = hp; return NS_SUCCESS; } /*ARGSUSED*/ static int _dns_gethtbyaddr(void *rv, void *cb_data, va_list ap) { char qbuf[MAXDNAME + 1], *qp, *ep; int n; querybuf *buf; struct hostent *hp; const unsigned char *uaddr; int len, af, advance; res_state res; unsigned netid, mark; res_static rs = __res_get_static(); assert(rv != NULL); uaddr = va_arg(ap, unsigned char *); len = va_arg(ap, int); af = va_arg(ap, int); netid = va_arg(ap, unsigned); mark = va_arg(ap, unsigned); switch (af) { case AF_INET: (void)snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa", (uaddr[3] & 0xff), (uaddr[2] & 0xff), (uaddr[1] & 0xff), (uaddr[0] & 0xff)); break; case AF_INET6: qp = qbuf; ep = qbuf + sizeof(qbuf) - 1; for (n = IN6ADDRSZ - 1; n >= 0; n--) { advance = snprintf(qp, (size_t)(ep - qp), "%x.%x.", uaddr[n] & 0xf, ((unsigned int)uaddr[n] >> 4) & 0xf); if (advance > 0 && qp + advance < ep) qp += advance; else { h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } } if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) { h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } break; default: abort(); } buf = malloc(sizeof(*buf)); if (buf == NULL) { h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } res = __res_get_state(); if (res == NULL) { free(buf); return NS_NOTFOUND; } res_setnetid(res, netid); res_setmark(res, mark); n = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf)); if (n < 0) { free(buf); dprintf("res_nquery failed (%d)\n", res, n); __res_put_state(res); return NS_NOTFOUND; } hp = getanswer(buf, n, qbuf, T_PTR, res); free(buf); if (hp == NULL) { __res_put_state(res); switch (h_errno) { case HOST_NOT_FOUND: return NS_NOTFOUND; case TRY_AGAIN: return NS_TRYAGAIN; default: return NS_UNAVAIL; } } hp->h_addrtype = af; hp->h_length = len; (void)memcpy(rs->host_addr, uaddr, (size_t)len); rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr; rs->h_addr_ptrs[1] = NULL; if (af == AF_INET && (res->options & RES_USE_INET6)) { map_v4v6_address((char *)(void *)rs->host_addr, (char *)(void *)rs->host_addr); hp->h_addrtype = AF_INET6; hp->h_length = IN6ADDRSZ; } __res_put_state(res); *((struct hostent **)rv) = hp; h_errno = NETDB_SUCCESS; return NS_SUCCESS; }