| /* $NetBSD: gethnamaddr.c,v 1.91 2014/06/19 15:08:18 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-- |
| */ |
| |
| #define LOG_TAG "resolv" |
| |
| #include "gethnamaddr.h" |
| |
| #include <android-base/logging.h> |
| #include <arpa/inet.h> |
| #include <arpa/nameser.h> |
| #include <assert.h> |
| #include <ctype.h> |
| #include <errno.h> |
| #include <netdb.h> |
| #include <netinet/in.h> |
| #include <stdarg.h> |
| #include <stdbool.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/param.h> |
| #include <sys/socket.h> |
| #include <sys/un.h> |
| #include <unistd.h> |
| #include <functional> |
| #include <vector> |
| |
| #include "Experiments.h" |
| #include "hostent.h" |
| #include "netd_resolv/resolv.h" |
| #include "res_comp.h" |
| #include "res_debug.h" // p_class(), p_type() |
| #include "resolv_cache.h" |
| #include "resolv_private.h" |
| #include "stats.pb.h" |
| |
| using android::net::NetworkDnsEventReported; |
| |
| constexpr int MAXADDRS = 35; |
| |
| typedef union { |
| HEADER hdr; |
| uint8_t buf[MAXPACKET]; |
| } querybuf; |
| |
| static void pad_v4v6_hostent(struct hostent* hp, char** bpp, char* ep); |
| static int dns_gethtbyaddr(const unsigned char* uaddr, int len, int af, |
| const android_net_context* netcontext, getnamaddr* info, |
| NetworkDnsEventReported* event); |
| static int dns_gethtbyname(ResState* res, const char* name, int af, getnamaddr* info); |
| |
| #define BOUNDED_INCR(x) \ |
| do { \ |
| BOUNDS_CHECK(cp, x); \ |
| cp += (x); \ |
| } while (0) |
| |
| #define BOUNDS_CHECK(ptr, count) \ |
| do { \ |
| if (eom - (ptr) < (count)) goto no_recovery; \ |
| } while (0) |
| |
| static struct hostent* getanswer(const querybuf* _Nonnull answer, int anslen, |
| const char* _Nonnull qname, int qtype, struct hostent* hent, |
| char* buf, size_t buflen, int* he) { |
| const HEADER* hp; |
| const uint8_t* cp; |
| int n; |
| size_t qlen; |
| const uint8_t *eom, *erdata; |
| char *bp, **hap, *ep; |
| int ancount, qdcount; |
| int haveanswer, had_error; |
| int toobig = 0; |
| char tbuf[MAXDNAME]; |
| char* addr_ptrs[MAXADDRS]; |
| const char* tname; |
| std::vector<char*> aliases; |
| |
| tname = qname; |
| hent->h_name = NULL; |
| eom = answer->buf + anslen; |
| |
| bool (*name_ok)(const char* dn); |
| switch (qtype) { |
| case T_A: |
| case T_AAAA: |
| name_ok = res_hnok; |
| break; |
| case T_PTR: |
| name_ok = res_dnok; |
| break; |
| default: |
| *he = NO_RECOVERY; |
| return NULL; /* XXX should be abort(); */ |
| } |
| |
| /* |
| * find first satisfactory answer |
| */ |
| hp = &answer->hdr; |
| ancount = ntohs(hp->ancount); |
| qdcount = ntohs(hp->qdcount); |
| bp = buf; |
| ep = buf + buflen; |
| cp = answer->buf; |
| BOUNDED_INCR(HFIXEDSZ); |
| if (qdcount != 1) goto no_recovery; |
| |
| n = dn_expand(answer->buf, eom, cp, bp, (int) (ep - bp)); |
| if ((n < 0) || !name_ok(bp)) goto no_recovery; |
| |
| 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 = (int) strlen(bp) + 1; /* for the \0 */ |
| if (n >= MAXHOSTNAMELEN) goto no_recovery; |
| hent->h_name = bp; |
| bp += n; |
| /* The qname can be abbreviated, but h_name is now absolute. */ |
| qname = hent->h_name; |
| } |
| hent->h_addr_list = hap = addr_ptrs; |
| *hap = NULL; |
| haveanswer = 0; |
| had_error = 0; |
| while (ancount-- > 0 && cp < eom && !had_error) { |
| n = dn_expand(answer->buf, eom, cp, bp, (int) (ep - bp)); |
| if ((n < 0) || !name_ok(bp)) { |
| had_error++; |
| continue; |
| } |
| cp += n; /* name */ |
| BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ); |
| int type = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; /* type */ |
| int cl = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ + INT32SZ; /* class, TTL */ |
| n = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; /* len */ |
| BOUNDS_CHECK(cp, n); |
| erdata = cp + n; |
| if (cl != C_IN) { |
| /* XXX - debug? syslog? */ |
| cp += n; |
| continue; /* XXX - had_error++ ? */ |
| } |
| if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) { |
| n = dn_expand(answer->buf, eom, cp, tbuf, (int) sizeof tbuf); |
| if ((n < 0) || !name_ok(tbuf)) { |
| had_error++; |
| continue; |
| } |
| cp += n; |
| if (cp != erdata) goto no_recovery; |
| /* Store alias. */ |
| aliases.push_back(bp); |
| n = (int) strlen(bp) + 1; /* for the \0 */ |
| if (n >= MAXHOSTNAMELEN) { |
| had_error++; |
| continue; |
| } |
| bp += n; |
| /* Get canonical name. */ |
| n = (int) strlen(tbuf) + 1; /* for the \0 */ |
| if (n > ep - bp || n >= MAXHOSTNAMELEN) { |
| had_error++; |
| continue; |
| } |
| strlcpy(bp, tbuf, (size_t)(ep - bp)); |
| hent->h_name = bp; |
| bp += n; |
| continue; |
| } |
| if (qtype == T_PTR && type == T_CNAME) { |
| n = dn_expand(answer->buf, eom, cp, tbuf, (int) sizeof tbuf); |
| if (n < 0 || !res_dnok(tbuf)) { |
| had_error++; |
| continue; |
| } |
| cp += n; |
| if (cp != erdata) goto no_recovery; |
| /* Get canonical name. */ |
| n = (int) 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) |
| LOG(DEBUG) << __func__ << ": asked for \"" << qname << " " << p_class(C_IN) << " " |
| << p_type(qtype) << "\", got type \"" << p_type(type) << "\""; |
| cp += n; |
| continue; /* XXX - had_error++ ? */ |
| } |
| switch (type) { |
| case T_PTR: |
| if (strcasecmp(tname, bp) != 0) { |
| LOG(DEBUG) << __func__ << ": asked for \"" << qname << "\", got \"" << bp |
| << "\""; |
| cp += n; |
| continue; /* XXX - had_error++ ? */ |
| } |
| n = dn_expand(answer->buf, eom, cp, bp, (int) (ep - bp)); |
| if ((n < 0) || !res_hnok(bp)) { |
| had_error++; |
| break; |
| } |
| cp += n; |
| if (cp != erdata) goto no_recovery; |
| if (!haveanswer) |
| hent->h_name = bp; |
| else |
| aliases.push_back(bp); |
| if (n != -1) { |
| n = (int) strlen(bp) + 1; /* for the \0 */ |
| if (n >= MAXHOSTNAMELEN) { |
| had_error++; |
| break; |
| } |
| bp += n; |
| } |
| break; |
| case T_A: |
| case T_AAAA: |
| if (strcasecmp(hent->h_name, bp) != 0) { |
| LOG(DEBUG) << __func__ << ": asked for \"" << hent->h_name << "\", got \"" << bp |
| << "\""; |
| cp += n; |
| continue; /* XXX - had_error++ ? */ |
| } |
| if (n != hent->h_length) { |
| cp += n; |
| continue; |
| } |
| if (type == T_AAAA) { |
| struct in6_addr in6; |
| memcpy(&in6, cp, NS_IN6ADDRSZ); |
| if (IN6_IS_ADDR_V4MAPPED(&in6)) { |
| cp += n; |
| continue; |
| } |
| } |
| if (!haveanswer) { |
| int nn; |
| |
| hent->h_name = bp; |
| nn = (int) strlen(bp) + 1; /* for the \0 */ |
| bp += nn; |
| } |
| |
| bp = align_ptr<sizeof(int32_t)>(bp); |
| |
| if (bp + n >= ep) { |
| LOG(DEBUG) << __func__ << ": size (" << n << ") too big"; |
| had_error++; |
| continue; |
| } |
| if (hap >= &addr_ptrs[MAXADDRS - 1]) { |
| if (!toobig++) { |
| LOG(DEBUG) << __func__ << ": Too many addresses (" << MAXADDRS << ")"; |
| } |
| cp += n; |
| continue; |
| } |
| (void) memcpy(*hap++ = bp, cp, (size_t) n); |
| bp += n; |
| cp += n; |
| if (cp != erdata) goto no_recovery; |
| break; |
| default: |
| abort(); |
| } |
| if (!had_error) haveanswer++; |
| } |
| if (haveanswer) { |
| *hap = NULL; |
| if (!hent->h_name) { |
| n = (int) strlen(qname) + 1; /* for the \0 */ |
| if (n > ep - bp || n >= MAXHOSTNAMELEN) goto no_recovery; |
| strlcpy(bp, qname, (size_t)(ep - bp)); |
| hent->h_name = bp; |
| bp += n; |
| } |
| if (hent->h_addrtype == AF_INET) pad_v4v6_hostent(hent, &bp, ep); |
| goto success; |
| } |
| no_recovery: |
| *he = NO_RECOVERY; |
| return NULL; |
| success: |
| bp = align_ptr(bp); |
| aliases.push_back(nullptr); |
| qlen = aliases.size() * sizeof(*hent->h_aliases); |
| if ((size_t)(ep - bp) < qlen) goto nospc; |
| hent->h_aliases = (char**) bp; |
| memcpy(bp, aliases.data(), qlen); |
| |
| bp += qlen; |
| n = (int) (hap - addr_ptrs); |
| qlen = (n + 1) * sizeof(*hent->h_addr_list); |
| if ((size_t)(ep - bp) < qlen) goto nospc; |
| hent->h_addr_list = (char**) bp; |
| memcpy(bp, addr_ptrs, qlen); |
| *he = NETDB_SUCCESS; |
| return hent; |
| nospc: |
| errno = ENOSPC; |
| *he = NETDB_INTERNAL; |
| return NULL; |
| } |
| |
| int resolv_gethostbyname(const char* name, int af, hostent* hp, char* buf, size_t buflen, |
| const android_net_context* netcontext, hostent** result, |
| NetworkDnsEventReported* event) { |
| if (name == nullptr || hp == nullptr) { |
| return EAI_SYSTEM; |
| } |
| |
| getnamaddr info; |
| ResState res(netcontext, event); |
| |
| setMdnsFlag(name, &(res.flags)); |
| |
| size_t size; |
| switch (af) { |
| case AF_INET: |
| size = NS_INADDRSZ; |
| break; |
| case AF_INET6: |
| size = NS_IN6ADDRSZ; |
| break; |
| default: |
| return EAI_FAMILY; |
| } |
| if (buflen < size) goto nospc; |
| |
| hp->h_addrtype = af; |
| hp->h_length = (int) size; |
| |
| /* |
| * disallow names consisting only of digits/dots, unless |
| * they end in a dot. |
| */ |
| if (isdigit((uint8_t)name[0])) { |
| for (const char* 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. |
| */ |
| goto fake; |
| } |
| if (!isdigit((uint8_t)*cp) && *cp != '.') break; |
| } |
| } |
| if ((isxdigit((uint8_t)name[0]) && strchr(name, ':') != NULL) || name[0] == ':') { |
| for (const char* 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. |
| */ |
| goto fake; |
| } |
| if (!isxdigit((uint8_t)*cp) && *cp != ':' && *cp != '.') break; |
| } |
| } |
| |
| info.hp = hp; |
| info.buf = buf; |
| info.buflen = buflen; |
| if (_hf_gethtbyname2(name, af, &info)) { |
| int error = dns_gethtbyname(&res, name, af, &info); |
| if (error != 0) return error; |
| } |
| *result = hp; |
| return 0; |
| nospc: |
| return EAI_MEMORY; |
| fake: |
| HENT_ARRAY(hp->h_addr_list, 1, buf, buflen); |
| HENT_ARRAY(hp->h_aliases, 0, buf, buflen); |
| |
| hp->h_aliases[0] = NULL; |
| if (size > buflen) goto nospc; |
| |
| if (inet_pton(af, name, buf) <= 0) { |
| return EAI_NODATA; |
| } |
| hp->h_addr_list[0] = buf; |
| hp->h_addr_list[1] = NULL; |
| buf += size; |
| buflen -= size; |
| HENT_SCOPY(hp->h_name, name, buf, buflen); |
| *result = hp; |
| return 0; |
| } |
| |
| int resolv_gethostbyaddr(const void* _Nonnull addr, socklen_t len, int af, hostent* hp, char* buf, |
| size_t buflen, const struct android_net_context* netcontext, |
| hostent** result, NetworkDnsEventReported* event) { |
| const uint8_t* uaddr = (const uint8_t*)addr; |
| socklen_t size; |
| struct getnamaddr info; |
| |
| if (af == AF_INET6 && len == NS_IN6ADDRSZ && |
| (IN6_IS_ADDR_LINKLOCAL((const struct in6_addr*) addr) || |
| IN6_IS_ADDR_SITELOCAL((const struct in6_addr*) addr))) { |
| return EAI_NODATA; |
| } |
| if (af == AF_INET6 && len == NS_IN6ADDRSZ && |
| (IN6_IS_ADDR_V4MAPPED((const struct in6_addr*) addr) || |
| IN6_IS_ADDR_V4COMPAT((const struct in6_addr*) addr))) { |
| /* Unmap. */ |
| uaddr += NS_IN6ADDRSZ - NS_INADDRSZ; |
| addr = uaddr; |
| af = AF_INET; |
| len = NS_INADDRSZ; |
| } |
| switch (af) { |
| case AF_INET: |
| size = NS_INADDRSZ; |
| break; |
| case AF_INET6: |
| size = NS_IN6ADDRSZ; |
| break; |
| default: |
| return EAI_FAMILY; |
| } |
| if (size != len) { |
| // TODO: Consider converting to a private extended EAI_* error code. |
| // Currently, the EAI_* value has no corresponding error code for invalid argument socket |
| // length. In order to not rely on errno, convert the original error code pair, EAI_SYSTEM |
| // and EINVAL, to EAI_FAIL. |
| return EAI_FAIL; |
| } |
| info.hp = hp; |
| info.buf = buf; |
| info.buflen = buflen; |
| if (_hf_gethtbyaddr(uaddr, len, af, &info)) { |
| int error = dns_gethtbyaddr(uaddr, len, af, netcontext, &info, event); |
| if (error != 0) return error; |
| } |
| *result = hp; |
| return 0; |
| } |
| |
| // TODO: Consider leaving function without returning error code as _gethtent() does because |
| // the error code of the caller does not currently return to netd. |
| struct hostent* netbsd_gethostent_r(FILE* hf, struct hostent* hent, char* buf, size_t buflen, |
| int* he) { |
| char *name; |
| char* cp; |
| int af, len; |
| size_t anum; |
| struct in6_addr host_addr; |
| std::vector<char*> aliases; |
| |
| if (hf == NULL) { |
| *he = NETDB_INTERNAL; |
| errno = EINVAL; |
| return NULL; |
| } |
| char* p = NULL; |
| |
| // Allocate a new space to read file lines like upstream does. |
| const size_t line_buf_size = MAXPACKET; |
| if ((p = (char*) malloc(line_buf_size)) == NULL) { |
| goto nospc; |
| } |
| for (;;) { |
| if (!fgets(p, line_buf_size, hf)) { |
| free(p); |
| *he = HOST_NOT_FOUND; |
| return NULL; |
| } |
| if (*p == '#') { |
| continue; |
| } |
| if (!(cp = strpbrk(p, "#\n"))) { |
| continue; |
| } |
| *cp = '\0'; |
| if (!(cp = strpbrk(p, " \t"))) continue; |
| *cp++ = '\0'; |
| if (inet_pton(AF_INET6, p, &host_addr) > 0) { |
| af = AF_INET6; |
| len = NS_IN6ADDRSZ; |
| } else { |
| if (inet_pton(AF_INET, p, &host_addr) <= 0) continue; |
| af = AF_INET; |
| len = NS_INADDRSZ; |
| } |
| |
| /* if this is not something we're looking for, skip it. */ |
| if (hent->h_addrtype != 0 && hent->h_addrtype != af) continue; |
| if (hent->h_length != 0 && hent->h_length != len) continue; |
| |
| while (*cp == ' ' || *cp == '\t') cp++; |
| if ((cp = strpbrk(name = cp, " \t")) != NULL) *cp++ = '\0'; |
| while (cp && *cp) { |
| if (*cp == ' ' || *cp == '\t') { |
| cp++; |
| continue; |
| } |
| aliases.push_back(cp); |
| if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0'; |
| } |
| break; |
| } |
| hent->h_length = len; |
| hent->h_addrtype = af; |
| HENT_ARRAY(hent->h_addr_list, 1, buf, buflen); |
| anum = aliases.size(); |
| HENT_ARRAY(hent->h_aliases, anum, buf, buflen); |
| HENT_COPY(hent->h_addr_list[0], &host_addr, hent->h_length, buf, buflen); |
| hent->h_addr_list[1] = NULL; |
| |
| /* Reserve space for mapping IPv4 address to IPv6 address in place */ |
| if (hent->h_addrtype == AF_INET) { |
| HENT_COPY(buf, NAT64_PAD, sizeof(NAT64_PAD), buf, buflen); |
| } |
| |
| HENT_SCOPY(hent->h_name, name, buf, buflen); |
| for (size_t i = 0; i < anum; i++) HENT_SCOPY(hent->h_aliases[i], aliases[i], buf, buflen); |
| hent->h_aliases[anum] = NULL; |
| *he = NETDB_SUCCESS; |
| free(p); |
| return hent; |
| nospc: |
| free(p); |
| errno = ENOSPC; |
| *he = NETDB_INTERNAL; |
| return NULL; |
| } |
| |
| /* Reserve space for mapping IPv4 address to IPv6 address in place */ |
| static void pad_v4v6_hostent(struct hostent* _Nonnull hp, char** _Nonnull bpp, char* _Nonnull ep) { |
| if (hp->h_addrtype != AF_INET || hp->h_length != NS_INADDRSZ) return; |
| for (char** ap = hp->h_addr_list; *ap; ap++) { |
| char* const bp = align_ptr<sizeof(int32_t)>(*bpp); |
| |
| if (ep - bp < NS_IN6ADDRSZ) { |
| // Out of space. Truncate address list here. |
| *ap = nullptr; |
| return; |
| } |
| memcpy(bp, *ap, NS_INADDRSZ); |
| memcpy(bp + NS_INADDRSZ, NAT64_PAD, sizeof(NAT64_PAD)); |
| *ap = bp; |
| *bpp = bp + NS_IN6ADDRSZ; |
| } |
| } |
| |
| static int dns_gethtbyname(ResState* res, const char* name, int addr_type, getnamaddr* info) { |
| int n, type; |
| info->hp->h_addrtype = addr_type; |
| |
| switch (info->hp->h_addrtype) { |
| case AF_INET: |
| info->hp->h_length = NS_INADDRSZ; |
| type = T_A; |
| break; |
| case AF_INET6: |
| info->hp->h_length = NS_IN6ADDRSZ; |
| type = T_AAAA; |
| break; |
| default: |
| return EAI_FAMILY; |
| } |
| auto buf = std::make_unique<querybuf>(); |
| |
| int he; |
| const unsigned qclass = isMdnsResolution(res->flags) ? C_IN | C_UNICAST : C_IN; |
| n = res_nsearch(res, name, qclass, type, {buf->buf, (int)sizeof(buf->buf)}, &he); |
| if (n < 0) { |
| LOG(DEBUG) << __func__ << ": res_nsearch failed (" << n << ")"; |
| // Return h_errno (he) to catch more detailed errors rather than EAI_NODATA. |
| // Note that res_nsearch() doesn't set the pair NETDB_INTERNAL and errno. |
| // See also herrnoToAiErrno(). |
| return herrnoToAiErrno(he); |
| } |
| hostent* hp = getanswer(buf.get(), n, name, type, info->hp, info->buf, info->buflen, &he); |
| if (hp == NULL) return herrnoToAiErrno(he); |
| |
| return 0; |
| } |
| |
| static int dns_gethtbyaddr(const unsigned char* uaddr, int len, int af, |
| const android_net_context* netcontext, getnamaddr* info, |
| NetworkDnsEventReported* event) { |
| char qbuf[MAXDNAME + 1], *qp, *ep; |
| int n; |
| int advance; |
| |
| info->hp->h_length = len; |
| info->hp->h_addrtype = af; |
| |
| switch (info->hp->h_addrtype) { |
| 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 = NS_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 { |
| // TODO: Consider converting to a private extended EAI_* error code. |
| // Currently, the EAI_* value has no corresponding error code for an internal |
| // out of buffer space. In order to not rely on errno, convert the original |
| // error code EAI_SYSTEM to EAI_MEMORY. |
| return EAI_MEMORY; |
| } |
| } |
| if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) { |
| // TODO: Consider converting to a private extended EAI_* error code. |
| // Currently, the EAI_* value has no corresponding error code for an internal |
| // out of buffer space. In order to not rely on errno, convert the original |
| // error code EAI_SYSTEM to EAI_MEMORY. |
| return EAI_MEMORY; |
| } |
| break; |
| default: |
| return EAI_FAMILY; |
| } |
| |
| auto buf = std::make_unique<querybuf>(); |
| |
| ResState res(netcontext, event); |
| int he; |
| n = res_nquery(&res, qbuf, C_IN, T_PTR, {buf->buf, (int)sizeof(buf->buf)}, &he); |
| if (n < 0) { |
| LOG(DEBUG) << __func__ << ": res_nquery failed (" << n << ")"; |
| // Note that res_nquery() doesn't set the pair NETDB_INTERNAL and errno. |
| // Return h_errno (he) to catch more detailed errors rather than EAI_NODATA. |
| // See also herrnoToAiErrno(). |
| return herrnoToAiErrno(he); |
| } |
| hostent* hp = getanswer(buf.get(), n, qbuf, T_PTR, info->hp, info->buf, info->buflen, &he); |
| if (hp == NULL) return herrnoToAiErrno(he); |
| |
| char* bf = (char*) (hp->h_addr_list + 2); |
| size_t blen = (size_t)(bf - info->buf); |
| if (blen + info->hp->h_length > info->buflen) goto nospc; |
| hp->h_addr_list[0] = bf; |
| hp->h_addr_list[1] = NULL; |
| memcpy(bf, uaddr, (size_t) info->hp->h_length); |
| |
| /* Reserve enough space for mapping IPv4 address to IPv6 address in place */ |
| if (info->hp->h_addrtype == AF_INET) { |
| if (blen + NS_IN6ADDRSZ > info->buflen) goto nospc; |
| // Pad zero to the unused address space |
| memcpy(bf + NS_INADDRSZ, NAT64_PAD, sizeof(NAT64_PAD)); |
| } |
| |
| return 0; |
| |
| nospc: |
| return EAI_MEMORY; |
| } |
| |
| int herrnoToAiErrno(int he) { |
| switch (he) { |
| // extended h_errno |
| case NETD_RESOLV_H_ERRNO_EXT_TIMEOUT: |
| return NETD_RESOLV_TIMEOUT; |
| // legacy h_errno |
| case NETDB_SUCCESS: |
| return 0; |
| case HOST_NOT_FOUND: // TODO: Perhaps convert HOST_NOT_FOUND to EAI_NONAME instead |
| case NO_DATA: // NO_ADDRESS |
| return EAI_NODATA; |
| case TRY_AGAIN: |
| return EAI_AGAIN; |
| case NETDB_INTERNAL: |
| // TODO: Remove ENOSPC and call abort() immediately whenever any allocation fails. |
| if (errno == ENOSPC) return EAI_MEMORY; |
| // Theoretically, this should not happen. Leave this here just in case. |
| // Currently, getanswer() of {gethnamaddr, getaddrinfo}.cpp, res_nsearch() and |
| // res_searchN() use this function to convert error code. Only getanswer() |
| // of gethnamaddr.cpp may return the error code pair, herrno NETDB_INTERNAL and |
| // errno ENOSPC, which has already converted to EAI_MEMORY. The remaining functions |
| // don't set the pair herrno and errno. |
| return EAI_SYSTEM; // see errno for detail |
| case NO_RECOVERY: |
| default: |
| return EAI_FAIL; // TODO: Perhaps convert default to EAI_MAX (unknown error) instead |
| } |
| } |
| |
| void setMdnsFlag(std::string_view hostname, uint32_t* flags) { |
| if (hostname.ends_with(".local") && |
| android::net::Experiments::getInstance()->getFlag("mdns_resolution", 1)) |
| *flags |= RES_F_MDNS; |
| } |
| |
| bool isMdnsResolution(uint32_t flags) { |
| return flags & RES_F_MDNS; |
| } |