| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * 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. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 |
| * COPYRIGHT OWNER 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. |
| */ |
| |
| #define LOG_TAG "resolv" |
| |
| #include "resolv_cache.h" |
| |
| #include <resolv.h> |
| #include <stdarg.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| #include <algorithm> |
| #include <mutex> |
| #include <set> |
| #include <string> |
| #include <unordered_map> |
| #include <vector> |
| |
| #include <arpa/inet.h> |
| #include <arpa/nameser.h> |
| #include <errno.h> |
| #include <linux/if.h> |
| #include <net/if.h> |
| #include <netdb.h> |
| |
| #include <aidl/android/net/IDnsResolver.h> |
| #include <android-base/logging.h> |
| #include <android-base/parseint.h> |
| #include <android-base/strings.h> |
| #include <android-base/thread_annotations.h> |
| #include <android/multinetwork.h> // ResNsendFlags |
| |
| #include <server_configurable_flags/get_flags.h> |
| |
| #include "DnsStats.h" |
| #include "Experiments.h" |
| #include "res_comp.h" |
| #include "res_debug.h" |
| #include "resolv_private.h" |
| #include "util.h" |
| |
| using aidl::android::net::IDnsResolver; |
| using aidl::android::net::ResolverOptionsParcel; |
| using android::net::DnsQueryEvent; |
| using android::net::DnsStats; |
| using android::net::Experiments; |
| using android::net::PROTO_DOH; |
| using android::net::PROTO_DOT; |
| using android::net::PROTO_MDNS; |
| using android::net::PROTO_TCP; |
| using android::net::PROTO_UDP; |
| using android::net::Protocol; |
| using android::netdutils::DumpWriter; |
| using android::netdutils::IPSockAddr; |
| using std::span; |
| |
| /* This code implements a small and *simple* DNS resolver cache. |
| * |
| * It is only used to cache DNS answers for a time defined by the smallest TTL |
| * among the answer records in order to reduce DNS traffic. It is not supposed |
| * to be a full DNS cache, since we plan to implement that in the future in a |
| * dedicated process running on the system. |
| * |
| * Note that its design is kept simple very intentionally, i.e.: |
| * |
| * - it takes raw DNS query packet data as input, and returns raw DNS |
| * answer packet data as output |
| * |
| * (this means that two similar queries that encode the DNS name |
| * differently will be treated distinctly). |
| * |
| * the smallest TTL value among the answer records are used as the time |
| * to keep an answer in the cache. |
| * |
| * this is bad, but we absolutely want to avoid parsing the answer packets |
| * (and should be solved by the later full DNS cache process). |
| * |
| * - the implementation is just a (query-data) => (answer-data) hash table |
| * with a trivial least-recently-used expiration policy. |
| * |
| * Doing this keeps the code simple and avoids to deal with a lot of things |
| * that a full DNS cache is expected to do. |
| * |
| * The API is also very simple: |
| * |
| * - the client calls resolv_cache_lookup() before performing a query |
| * |
| * If the function returns RESOLV_CACHE_FOUND, a copy of the answer data |
| * has been copied into the client-provided answer buffer. |
| * |
| * If the function returns RESOLV_CACHE_NOTFOUND, the client should perform |
| * a request normally, *then* call resolv_cache_add() to add the received |
| * answer to the cache. |
| * |
| * If the function returns RESOLV_CACHE_UNSUPPORTED, the client should |
| * perform a request normally, and *not* call resolv_cache_add() |
| * |
| * Note that RESOLV_CACHE_UNSUPPORTED is also returned if the answer buffer |
| * is too short to accomodate the cached result. |
| */ |
| |
| /* Default number of entries kept in the cache. This value has been |
| * determined by browsing through various sites and counting the number |
| * of corresponding requests. Keep in mind that our framework is currently |
| * performing two requests per name lookup (one for IPv4, the other for IPv6) |
| * |
| * www.google.com 4 |
| * www.ysearch.com 6 |
| * www.amazon.com 8 |
| * www.nytimes.com 22 |
| * www.espn.com 28 |
| * www.msn.com 28 |
| * www.lemonde.fr 35 |
| * |
| * (determined in 2009-2-17 from Paris, France, results may vary depending |
| * on location) |
| * |
| * most high-level websites use lots of media/ad servers with different names |
| * but these are generally reused when browsing through the site. |
| * |
| * As such, a value of 64 should be relatively comfortable at the moment. |
| * |
| * ****************************************** |
| * * NOTE - this has changed. |
| * * 1) we've added IPv6 support so each dns query results in 2 responses |
| * * 2) we've made this a system-wide cache, so the cost is less (it's not |
| * * duplicated in each process) and the need is greater (more processes |
| * * making different requests). |
| * * Upping by 2x for IPv6 |
| * * Upping by another 5x for the centralized nature |
| * ***************************************** |
| */ |
| const int CONFIG_MAX_ENTRIES = 64 * 2 * 5; |
| constexpr int DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY = -1; |
| |
| static time_t _time_now(void) { |
| struct timeval tv; |
| |
| gettimeofday(&tv, NULL); |
| return tv.tv_sec; |
| } |
| |
| /* reminder: the general format of a DNS packet is the following: |
| * |
| * HEADER (12 bytes) |
| * QUESTION (variable) |
| * ANSWER (variable) |
| * AUTHORITY (variable) |
| * ADDITIONNAL (variable) |
| * |
| * the HEADER is made of: |
| * |
| * ID : 16 : 16-bit unique query identification field |
| * |
| * QR : 1 : set to 0 for queries, and 1 for responses |
| * Opcode : 4 : set to 0 for queries |
| * AA : 1 : set to 0 for queries |
| * TC : 1 : truncation flag, will be set to 0 in queries |
| * RD : 1 : recursion desired |
| * |
| * RA : 1 : recursion available (0 in queries) |
| * Z : 3 : three reserved zero bits |
| * RCODE : 4 : response code (always 0=NOERROR in queries) |
| * |
| * QDCount: 16 : question count |
| * ANCount: 16 : Answer count (0 in queries) |
| * NSCount: 16: Authority Record count (0 in queries) |
| * ARCount: 16: Additionnal Record count (0 in queries) |
| * |
| * the QUESTION is made of QDCount Question Record (QRs) |
| * the ANSWER is made of ANCount RRs |
| * the AUTHORITY is made of NSCount RRs |
| * the ADDITIONNAL is made of ARCount RRs |
| * |
| * Each Question Record (QR) is made of: |
| * |
| * QNAME : variable : Query DNS NAME |
| * TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255) |
| * CLASS : 16 : class of query (IN=1) |
| * |
| * Each Resource Record (RR) is made of: |
| * |
| * NAME : variable : DNS NAME |
| * TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255) |
| * CLASS : 16 : class of query (IN=1) |
| * TTL : 32 : seconds to cache this RR (0=none) |
| * RDLENGTH: 16 : size of RDDATA in bytes |
| * RDDATA : variable : RR data (depends on TYPE) |
| * |
| * Each QNAME contains a domain name encoded as a sequence of 'labels' |
| * terminated by a zero. Each label has the following format: |
| * |
| * LEN : 8 : lenght of label (MUST be < 64) |
| * NAME : 8*LEN : label length (must exclude dots) |
| * |
| * A value of 0 in the encoding is interpreted as the 'root' domain and |
| * terminates the encoding. So 'www.android.com' will be encoded as: |
| * |
| * <3>www<7>android<3>com<0> |
| * |
| * Where <n> represents the byte with value 'n' |
| * |
| * Each NAME reflects the QNAME of the question, but has a slightly more |
| * complex encoding in order to provide message compression. This is achieved |
| * by using a 2-byte pointer, with format: |
| * |
| * TYPE : 2 : 0b11 to indicate a pointer, 0b01 and 0b10 are reserved |
| * OFFSET : 14 : offset to another part of the DNS packet |
| * |
| * The offset is relative to the start of the DNS packet and must point |
| * A pointer terminates the encoding. |
| * |
| * The NAME can be encoded in one of the following formats: |
| * |
| * - a sequence of simple labels terminated by 0 (like QNAMEs) |
| * - a single pointer |
| * - a sequence of simple labels terminated by a pointer |
| * |
| * A pointer shall always point to either a pointer of a sequence of |
| * labels (which can themselves be terminated by either a 0 or a pointer) |
| * |
| * The expanded length of a given domain name should not exceed 255 bytes. |
| * |
| * NOTE: we don't parse the answer packets, so don't need to deal with NAME |
| * records, only QNAMEs. |
| */ |
| |
| #define DNS_HEADER_SIZE 12 |
| |
| #define DNS_TYPE_A "\00\01" /* big-endian decimal 1 */ |
| #define DNS_TYPE_PTR "\00\014" /* big-endian decimal 12 */ |
| #define DNS_TYPE_MX "\00\017" /* big-endian decimal 15 */ |
| #define DNS_TYPE_AAAA "\00\034" /* big-endian decimal 28 */ |
| #define DNS_TYPE_ALL "\00\0377" /* big-endian decimal 255 */ |
| |
| #define DNS_CLASS_IN "\00\01" /* big-endian decimal 1 */ |
| #define MDNS_CLASS_UNICAST_IN "\200\01" /* big-endian decimal 32769 */ |
| |
| struct DnsPacket { |
| const uint8_t* base; |
| const uint8_t* end; |
| const uint8_t* cursor; |
| }; |
| |
| static uint8_t res_tolower(uint8_t c) { |
| return (c >= 'A' && c <= 'Z') ? (c | 0x20) : c; |
| } |
| |
| static int res_memcasecmp(const unsigned char *s1, const unsigned char *s2, size_t len) { |
| for (size_t i = 0; i < len; i++) { |
| int ch1 = *s1++; |
| int ch2 = *s2++; |
| int d = res_tolower(ch1) - res_tolower(ch2); |
| if (d != 0) { |
| return d; |
| } |
| } |
| return 0; |
| } |
| |
| static void _dnsPacket_init(DnsPacket* packet, const uint8_t* buff, int bufflen) { |
| packet->base = buff; |
| packet->end = buff + bufflen; |
| packet->cursor = buff; |
| } |
| |
| static void _dnsPacket_rewind(DnsPacket* packet) { |
| packet->cursor = packet->base; |
| } |
| |
| static void _dnsPacket_skip(DnsPacket* packet, int count) { |
| const uint8_t* p = packet->cursor + count; |
| |
| if (p > packet->end) p = packet->end; |
| |
| packet->cursor = p; |
| } |
| |
| static int _dnsPacket_readInt16(DnsPacket* packet) { |
| const uint8_t* p = packet->cursor; |
| |
| if (p + 2 > packet->end) return -1; |
| |
| packet->cursor = p + 2; |
| return (p[0] << 8) | p[1]; |
| } |
| |
| /** QUERY CHECKING **/ |
| |
| /* check bytes in a dns packet. returns 1 on success, 0 on failure. |
| * the cursor is only advanced in the case of success |
| */ |
| static int _dnsPacket_checkBytes(DnsPacket* packet, int numBytes, const void* bytes) { |
| const uint8_t* p = packet->cursor; |
| |
| if (p + numBytes > packet->end) return 0; |
| |
| if (memcmp(p, bytes, numBytes) != 0) return 0; |
| |
| packet->cursor = p + numBytes; |
| return 1; |
| } |
| |
| /* parse and skip a given QNAME stored in a query packet, |
| * from the current cursor position. returns 1 on success, |
| * or 0 for malformed data. |
| */ |
| static int _dnsPacket_checkQName(DnsPacket* packet) { |
| const uint8_t* p = packet->cursor; |
| const uint8_t* end = packet->end; |
| |
| for (;;) { |
| int c; |
| |
| if (p >= end) break; |
| |
| c = *p++; |
| |
| if (c == 0) { |
| packet->cursor = p; |
| return 1; |
| } |
| |
| /* we don't expect label compression in QNAMEs */ |
| if (c >= 64) break; |
| |
| p += c; |
| /* we rely on the bound check at the start |
| * of the loop here */ |
| } |
| /* malformed data */ |
| LOG(INFO) << __func__ << ": malformed QNAME"; |
| return 0; |
| } |
| |
| /* parse and skip a given QR stored in a packet. |
| * returns 1 on success, and 0 on failure |
| */ |
| static int _dnsPacket_checkQR(DnsPacket* packet) { |
| if (!_dnsPacket_checkQName(packet)) return 0; |
| |
| /* TYPE must be one of the things we support */ |
| if (!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_A) && |
| !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_PTR) && |
| !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_MX) && |
| !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_AAAA) && |
| !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_ALL)) { |
| LOG(INFO) << __func__ << ": unsupported TYPE"; |
| return 0; |
| } |
| /* CLASS must be IN */ |
| if (!_dnsPacket_checkBytes(packet, 2, DNS_CLASS_IN) && |
| !_dnsPacket_checkBytes(packet, 2, MDNS_CLASS_UNICAST_IN)) { |
| LOG(INFO) << __func__ << ": unsupported CLASS"; |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* check the header of a DNS Query packet, return 1 if it is one |
| * type of query we can cache, or 0 otherwise |
| */ |
| static int _dnsPacket_checkQuery(DnsPacket* packet) { |
| const uint8_t* p = packet->base; |
| int qdCount, anCount, dnCount, arCount; |
| |
| if (p + DNS_HEADER_SIZE > packet->end) { |
| LOG(INFO) << __func__ << ": query packet too small"; |
| return 0; |
| } |
| |
| /* QR must be set to 0, opcode must be 0 and AA must be 0 */ |
| /* RA, Z, and RCODE must be 0 */ |
| if ((p[2] & 0xFC) != 0 || (p[3] & 0xCF) != 0) { |
| LOG(INFO) << __func__ << ": query packet flags unsupported"; |
| return 0; |
| } |
| |
| /* Note that we ignore the TC, RD, CD, and AD bits here for the |
| * following reasons: |
| * |
| * - there is no point for a query packet sent to a server |
| * to have the TC bit set, but the implementation might |
| * set the bit in the query buffer for its own needs |
| * between a resolv_cache_lookup and a resolv_cache_add. |
| * We should not freak out if this is the case. |
| * |
| * - we consider that the result from a query might depend on |
| * the RD, AD, and CD bits, so these bits |
| * should be used to differentiate cached result. |
| * |
| * this implies that these bits are checked when hashing or |
| * comparing query packets, but not TC |
| */ |
| |
| /* ANCOUNT, DNCOUNT and ARCOUNT must be 0 */ |
| qdCount = (p[4] << 8) | p[5]; |
| anCount = (p[6] << 8) | p[7]; |
| dnCount = (p[8] << 8) | p[9]; |
| arCount = (p[10] << 8) | p[11]; |
| |
| if (anCount != 0 || dnCount != 0 || arCount > 1) { |
| LOG(INFO) << __func__ << ": query packet contains non-query records"; |
| return 0; |
| } |
| |
| if (qdCount == 0) { |
| LOG(INFO) << __func__ << ": query packet doesn't contain query record"; |
| return 0; |
| } |
| |
| /* Check QDCOUNT QRs */ |
| packet->cursor = p + DNS_HEADER_SIZE; |
| |
| for (; qdCount > 0; qdCount--) |
| if (!_dnsPacket_checkQR(packet)) return 0; |
| |
| return 1; |
| } |
| |
| /** QUERY HASHING SUPPORT |
| ** |
| ** THE FOLLOWING CODE ASSUMES THAT THE INPUT PACKET HAS ALREADY |
| ** BEEN SUCCESFULLY CHECKED. |
| **/ |
| |
| /* use 32-bit FNV hash function */ |
| #define FNV_MULT 16777619U |
| #define FNV_BASIS 2166136261U |
| |
| static unsigned _dnsPacket_hashBytes(DnsPacket* packet, int numBytes, unsigned hash) { |
| const uint8_t* p = packet->cursor; |
| const uint8_t* end = packet->end; |
| |
| while (numBytes > 0 && p < end) { |
| hash = hash * FNV_MULT ^ *p++; |
| numBytes--; |
| } |
| packet->cursor = p; |
| return hash; |
| } |
| |
| static unsigned _dnsPacket_hashQName(DnsPacket* packet, unsigned hash) { |
| const uint8_t* p = packet->cursor; |
| const uint8_t* end = packet->end; |
| |
| for (;;) { |
| if (p >= end) { /* should not happen */ |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: read-overflow"; |
| break; |
| } |
| |
| int c = *p++; |
| |
| if (c == 0) break; |
| |
| if (c >= 64) { |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: malformed domain"; |
| break; |
| } |
| if (p + c >= end) { |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: simple label read-overflow"; |
| break; |
| } |
| |
| while (c > 0) { |
| uint8_t ch = *p++; |
| ch = res_tolower(ch); |
| hash = hash * FNV_MULT ^ ch; |
| c--; |
| } |
| } |
| packet->cursor = p; |
| return hash; |
| } |
| |
| static unsigned _dnsPacket_hashQR(DnsPacket* packet, unsigned hash) { |
| hash = _dnsPacket_hashQName(packet, hash); |
| hash = _dnsPacket_hashBytes(packet, 4, hash); /* TYPE and CLASS */ |
| return hash; |
| } |
| |
| static unsigned _dnsPacket_hashRR(DnsPacket* packet, unsigned hash) { |
| int rdlength; |
| hash = _dnsPacket_hashQR(packet, hash); |
| hash = _dnsPacket_hashBytes(packet, 4, hash); /* TTL */ |
| rdlength = _dnsPacket_readInt16(packet); |
| hash = _dnsPacket_hashBytes(packet, rdlength, hash); /* RDATA */ |
| return hash; |
| } |
| |
| static unsigned _dnsPacket_hashQuery(DnsPacket* packet) { |
| unsigned hash = FNV_BASIS; |
| int count, arcount; |
| _dnsPacket_rewind(packet); |
| |
| /* ignore the ID */ |
| _dnsPacket_skip(packet, 2); |
| |
| /* we ignore the TC bit for reasons explained in |
| * _dnsPacket_checkQuery(). |
| * |
| * however we hash the RD bit to differentiate |
| * between answers for recursive and non-recursive |
| * queries. |
| */ |
| hash = hash * FNV_MULT ^ (packet->base[2] & 1); |
| |
| /* mark the first header byte as processed */ |
| _dnsPacket_skip(packet, 1); |
| |
| /* process the second header byte */ |
| hash = _dnsPacket_hashBytes(packet, 1, hash); |
| |
| /* read QDCOUNT */ |
| count = _dnsPacket_readInt16(packet); |
| |
| /* assume: ANcount and NScount are 0 */ |
| _dnsPacket_skip(packet, 4); |
| |
| /* read ARCOUNT */ |
| arcount = _dnsPacket_readInt16(packet); |
| |
| /* hash QDCOUNT QRs */ |
| for (; count > 0; count--) hash = _dnsPacket_hashQR(packet, hash); |
| |
| /* hash ARCOUNT RRs */ |
| for (; arcount > 0; arcount--) hash = _dnsPacket_hashRR(packet, hash); |
| |
| return hash; |
| } |
| |
| /** QUERY COMPARISON |
| ** |
| ** THE FOLLOWING CODE ASSUMES THAT THE INPUT PACKETS HAVE ALREADY |
| ** BEEN SUCCESSFULLY CHECKED. |
| **/ |
| |
| static int _dnsPacket_isEqualDomainName(DnsPacket* pack1, DnsPacket* pack2) { |
| const uint8_t* p1 = pack1->cursor; |
| const uint8_t* end1 = pack1->end; |
| const uint8_t* p2 = pack2->cursor; |
| const uint8_t* end2 = pack2->end; |
| |
| for (;;) { |
| if (p1 >= end1 || p2 >= end2) { |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: read-overflow"; |
| break; |
| } |
| int c1 = *p1++; |
| int c2 = *p2++; |
| if (c1 != c2) break; |
| |
| if (c1 == 0) { |
| pack1->cursor = p1; |
| pack2->cursor = p2; |
| return 1; |
| } |
| if (c1 >= 64) { |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: malformed domain"; |
| break; |
| } |
| if ((p1 + c1 > end1) || (p2 + c1 > end2)) { |
| LOG(INFO) << __func__ << ": INTERNAL_ERROR: simple label read-overflow"; |
| break; |
| } |
| if (res_memcasecmp(p1, p2, c1) != 0) break; |
| p1 += c1; |
| p2 += c1; |
| /* we rely on the bound checks at the start of the loop */ |
| } |
| /* not the same, or one is malformed */ |
| LOG(INFO) << __func__ << ": different DN"; |
| return 0; |
| } |
| |
| static int _dnsPacket_isEqualBytes(DnsPacket* pack1, DnsPacket* pack2, int numBytes) { |
| const uint8_t* p1 = pack1->cursor; |
| const uint8_t* p2 = pack2->cursor; |
| |
| if (p1 + numBytes > pack1->end || p2 + numBytes > pack2->end) return 0; |
| |
| if (memcmp(p1, p2, numBytes) != 0) return 0; |
| |
| pack1->cursor += numBytes; |
| pack2->cursor += numBytes; |
| return 1; |
| } |
| |
| static int _dnsPacket_isEqualQR(DnsPacket* pack1, DnsPacket* pack2) { |
| /* compare domain name encoding + TYPE + CLASS */ |
| if (!_dnsPacket_isEqualDomainName(pack1, pack2) || |
| !_dnsPacket_isEqualBytes(pack1, pack2, 2 + 2)) |
| return 0; |
| |
| return 1; |
| } |
| |
| static int _dnsPacket_isEqualRR(DnsPacket* pack1, DnsPacket* pack2) { |
| int rdlength1, rdlength2; |
| /* compare query + TTL */ |
| if (!_dnsPacket_isEqualQR(pack1, pack2) || !_dnsPacket_isEqualBytes(pack1, pack2, 4)) return 0; |
| |
| /* compare RDATA */ |
| rdlength1 = _dnsPacket_readInt16(pack1); |
| rdlength2 = _dnsPacket_readInt16(pack2); |
| if (rdlength1 != rdlength2 || !_dnsPacket_isEqualBytes(pack1, pack2, rdlength1)) return 0; |
| |
| return 1; |
| } |
| |
| static int _dnsPacket_isEqualQuery(DnsPacket* pack1, DnsPacket* pack2) { |
| int count1, count2, arcount1, arcount2; |
| |
| /* compare the headers, ignore most fields */ |
| _dnsPacket_rewind(pack1); |
| _dnsPacket_rewind(pack2); |
| |
| /* compare RD, ignore TC, see comment in _dnsPacket_checkQuery */ |
| if ((pack1->base[2] & 1) != (pack2->base[2] & 1)) { |
| LOG(INFO) << __func__ << ": different RD"; |
| return 0; |
| } |
| |
| if (pack1->base[3] != pack2->base[3]) { |
| LOG(INFO) << __func__ << ": different CD or AD"; |
| return 0; |
| } |
| |
| /* mark ID and header bytes as compared */ |
| _dnsPacket_skip(pack1, 4); |
| _dnsPacket_skip(pack2, 4); |
| |
| /* compare QDCOUNT */ |
| count1 = _dnsPacket_readInt16(pack1); |
| count2 = _dnsPacket_readInt16(pack2); |
| if (count1 != count2 || count1 < 0) { |
| LOG(INFO) << __func__ << ": different QDCOUNT"; |
| return 0; |
| } |
| |
| /* assume: ANcount and NScount are 0 */ |
| _dnsPacket_skip(pack1, 4); |
| _dnsPacket_skip(pack2, 4); |
| |
| /* compare ARCOUNT */ |
| arcount1 = _dnsPacket_readInt16(pack1); |
| arcount2 = _dnsPacket_readInt16(pack2); |
| if (arcount1 != arcount2 || arcount1 < 0) { |
| LOG(INFO) << __func__ << ": different ARCOUNT"; |
| return 0; |
| } |
| |
| /* compare the QDCOUNT QRs */ |
| for (; count1 > 0; count1--) { |
| if (!_dnsPacket_isEqualQR(pack1, pack2)) { |
| LOG(INFO) << __func__ << ": different QR"; |
| return 0; |
| } |
| } |
| |
| /* compare the ARCOUNT RRs */ |
| for (; arcount1 > 0; arcount1--) { |
| if (!_dnsPacket_isEqualRR(pack1, pack2)) { |
| LOG(INFO) << __func__ << ": different additional RR"; |
| return 0; |
| } |
| } |
| return 1; |
| } |
| |
| /* cache entry. for simplicity, 'hash' and 'hlink' are inlined in this |
| * structure though they are conceptually part of the hash table. |
| * |
| * similarly, mru_next and mru_prev are part of the global MRU list |
| */ |
| struct Entry { |
| unsigned int hash; /* hash value */ |
| struct Entry* hlink; /* next in collision chain */ |
| struct Entry* mru_prev; |
| struct Entry* mru_next; |
| |
| const uint8_t* query; |
| int querylen; |
| const uint8_t* answer; |
| int answerlen; |
| time_t expires; /* time_t when the entry isn't valid any more */ |
| int id; /* for debugging purpose */ |
| }; |
| |
| /* |
| * Find the TTL for a negative DNS result. This is defined as the minimum |
| * of the SOA records TTL and the MINIMUM-TTL field (RFC-2308). |
| * |
| * Return 0 if not found. |
| */ |
| static uint32_t answer_getNegativeTTL(ns_msg handle) { |
| int n, nscount; |
| uint32_t result = 0; |
| ns_rr rr; |
| |
| nscount = ns_msg_count(handle, ns_s_ns); |
| for (n = 0; n < nscount; n++) { |
| if ((ns_parserr(&handle, ns_s_ns, n, &rr) == 0) && (ns_rr_type(rr) == ns_t_soa)) { |
| const uint8_t* rdata = ns_rr_rdata(rr); // find the data |
| const uint8_t* edata = rdata + ns_rr_rdlen(rr); // add the len to find the end |
| int len; |
| uint32_t ttl, rec_result = rr.ttl; |
| |
| // find the MINIMUM-TTL field from the blob of binary data for this record |
| // skip the server name |
| len = dn_skipname(rdata, edata); |
| if (len == -1) continue; // error skipping |
| rdata += len; |
| |
| // skip the admin name |
| len = dn_skipname(rdata, edata); |
| if (len == -1) continue; // error skipping |
| rdata += len; |
| |
| if (edata - rdata != 5 * NS_INT32SZ) continue; |
| // skip: serial number + refresh interval + retry interval + expiry |
| rdata += NS_INT32SZ * 4; |
| // finally read the MINIMUM TTL |
| ttl = ntohl(*reinterpret_cast<const uint32_t*>(rdata)); |
| if (ttl < rec_result) { |
| rec_result = ttl; |
| } |
| // Now that the record is read successfully, apply the new min TTL |
| if (n == 0 || rec_result < result) { |
| result = rec_result; |
| } |
| } |
| } |
| return result; |
| } |
| |
| /* |
| * Parse the answer records and find the appropriate |
| * smallest TTL among the records. This might be from |
| * the answer records if found or from the SOA record |
| * if it's a negative result. |
| * |
| * The returned TTL is the number of seconds to |
| * keep the answer in the cache. |
| * |
| * In case of parse error zero (0) is returned which |
| * indicates that the answer shall not be cached. |
| */ |
| static uint32_t answer_getTTL(span<const uint8_t> answer) { |
| ns_msg handle; |
| int ancount, n; |
| uint32_t result, ttl; |
| ns_rr rr; |
| |
| result = 0; |
| if (ns_initparse(answer.data(), answer.size(), &handle) >= 0) { |
| // get number of answer records |
| ancount = ns_msg_count(handle, ns_s_an); |
| |
| if (ancount == 0) { |
| // a response with no answers? Cache this negative result. |
| result = answer_getNegativeTTL(handle); |
| } else { |
| for (n = 0; n < ancount; n++) { |
| if (ns_parserr(&handle, ns_s_an, n, &rr) == 0) { |
| ttl = rr.ttl; |
| if (n == 0 || ttl < result) { |
| result = ttl; |
| } |
| } else { |
| PLOG(INFO) << __func__ << ": ns_parserr failed ancount no = " << n; |
| } |
| } |
| } |
| } else { |
| PLOG(INFO) << __func__ << ": ns_initparse failed"; |
| } |
| |
| LOG(INFO) << __func__ << ": TTL = " << result; |
| return result; |
| } |
| |
| static void entry_free(Entry* e) { |
| /* everything is allocated in a single memory block */ |
| if (e) { |
| free(e); |
| } |
| } |
| |
| static void entry_mru_remove(Entry* e) { |
| e->mru_prev->mru_next = e->mru_next; |
| e->mru_next->mru_prev = e->mru_prev; |
| } |
| |
| static void entry_mru_add(Entry* e, Entry* list) { |
| Entry* first = list->mru_next; |
| |
| e->mru_next = first; |
| e->mru_prev = list; |
| |
| list->mru_next = e; |
| first->mru_prev = e; |
| } |
| |
| /* compute the hash of a given entry, this is a hash of most |
| * data in the query (key) */ |
| static unsigned entry_hash(const Entry* e) { |
| DnsPacket pack[1]; |
| |
| _dnsPacket_init(pack, e->query, e->querylen); |
| return _dnsPacket_hashQuery(pack); |
| } |
| |
| /* initialize an Entry as a search key, this also checks the input query packet |
| * returns 1 on success, or 0 in case of unsupported/malformed data */ |
| static int entry_init_key(Entry* e, span<const uint8_t> query) { |
| DnsPacket pack[1]; |
| |
| memset(e, 0, sizeof(*e)); |
| |
| e->query = query.data(); |
| e->querylen = query.size(); |
| e->hash = entry_hash(e); |
| |
| _dnsPacket_init(pack, e->query, e->querylen); |
| |
| return _dnsPacket_checkQuery(pack); |
| } |
| |
| /* allocate a new entry as a cache node */ |
| static Entry* entry_alloc(const Entry* init, span<const uint8_t> answer) { |
| Entry* e; |
| int size; |
| |
| size = sizeof(*e) + init->querylen + answer.size(); |
| e = (Entry*) calloc(size, 1); |
| if (e == NULL) return e; |
| |
| e->hash = init->hash; |
| e->query = (const uint8_t*) (e + 1); |
| e->querylen = init->querylen; |
| |
| memcpy((char*) e->query, init->query, e->querylen); |
| |
| e->answer = e->query + e->querylen; |
| e->answerlen = answer.size(); |
| |
| memcpy((char*)e->answer, answer.data(), e->answerlen); |
| |
| return e; |
| } |
| |
| static int entry_equals(const Entry* e1, const Entry* e2) { |
| DnsPacket pack1[1], pack2[1]; |
| |
| if (e1->querylen != e2->querylen) { |
| return 0; |
| } |
| _dnsPacket_init(pack1, e1->query, e1->querylen); |
| _dnsPacket_init(pack2, e2->query, e2->querylen); |
| |
| return _dnsPacket_isEqualQuery(pack1, pack2); |
| } |
| |
| /* We use a simple hash table with external collision lists |
| * for simplicity, the hash-table fields 'hash' and 'hlink' are |
| * inlined in the Entry structure. |
| */ |
| |
| /* Maximum time for a thread to wait for an pending request */ |
| constexpr int PENDING_REQUEST_TIMEOUT = 20; |
| |
| // lock protecting everything in NetConfig. |
| static std::mutex cache_mutex; |
| static std::condition_variable cv; |
| |
| namespace { |
| |
| // Map format: ReturnCode:rate_denom |
| // if the ReturnCode is not associated with any rate_denom, use default |
| // Sampling rate varies by return code; events to log are chosen randomly, with a |
| // probability proportional to the sampling rate. |
| constexpr const char DEFAULT_SUBSAMPLING_MAP[] = "default:8 0:400 2:110 7:110"; |
| constexpr const char DEFAULT_MDNS_SUBSAMPLING_MAP[] = "default:1"; |
| |
| std::unordered_map<int, uint32_t> resolv_get_dns_event_subsampling_map(bool isMdns) { |
| using android::base::ParseInt; |
| using android::base::ParseUint; |
| using android::base::Split; |
| using server_configurable_flags::GetServerConfigurableFlag; |
| std::unordered_map<int, uint32_t> sampling_rate_map{}; |
| const char* flag = isMdns ? "mdns_event_subsample_map" : "dns_event_subsample_map"; |
| const char* defaultMap = isMdns ? DEFAULT_MDNS_SUBSAMPLING_MAP : DEFAULT_SUBSAMPLING_MAP; |
| const std::vector<std::string> subsampling_vector = |
| Split(GetServerConfigurableFlag("netd_native", flag, defaultMap), " "); |
| |
| for (const auto& pair : subsampling_vector) { |
| std::vector<std::string> rate_denom = Split(pair, ":"); |
| int return_code; |
| uint32_t denom; |
| if (rate_denom.size() != 2) { |
| LOG(ERROR) << __func__ << ": invalid subsampling_pair = " << pair; |
| continue; |
| } |
| if (rate_denom[0] == "default") { |
| return_code = DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY; |
| } else if (!ParseInt(rate_denom[0], &return_code)) { |
| LOG(ERROR) << __func__ << ": parse subsampling_pair failed = " << pair; |
| continue; |
| } |
| if (!ParseUint(rate_denom[1], &denom)) { |
| LOG(ERROR) << __func__ << ": parse subsampling_pair failed = " << pair; |
| continue; |
| } |
| sampling_rate_map[return_code] = denom; |
| } |
| return sampling_rate_map; |
| } |
| |
| } // namespace |
| |
| // Note that Cache is not thread-safe per se, access to its members must be protected |
| // by an external mutex. |
| // |
| // TODO: move all cache manipulation code here and make data members private. |
| struct Cache { |
| Cache() { |
| entries.resize(CONFIG_MAX_ENTRIES); |
| mru_list.mru_prev = mru_list.mru_next = &mru_list; |
| } |
| ~Cache() { flush(); } |
| |
| void flush() { |
| for (int nn = 0; nn < CONFIG_MAX_ENTRIES; nn++) { |
| Entry** pnode = (Entry**)&entries[nn]; |
| |
| while (*pnode) { |
| Entry* node = *pnode; |
| *pnode = node->hlink; |
| entry_free(node); |
| } |
| } |
| |
| flushPendingRequests(); |
| |
| mru_list.mru_next = mru_list.mru_prev = &mru_list; |
| num_entries = 0; |
| last_id = 0; |
| |
| LOG(INFO) << "DNS cache flushed"; |
| } |
| |
| void flushPendingRequests() { |
| pending_req_info* ri = pending_requests.next; |
| while (ri) { |
| pending_req_info* tmp = ri; |
| ri = ri->next; |
| free(tmp); |
| } |
| |
| pending_requests.next = nullptr; |
| cv.notify_all(); |
| } |
| |
| int num_entries = 0; |
| |
| // TODO: convert to std::list |
| Entry mru_list; |
| int last_id = 0; |
| std::vector<Entry> entries; |
| |
| // TODO: convert to std::vector |
| struct pending_req_info { |
| unsigned int hash; |
| struct pending_req_info* next; |
| } pending_requests{}; |
| }; |
| |
| struct NetConfig { |
| explicit NetConfig(unsigned netId) : netid(netId) { |
| cache = std::make_unique<Cache>(); |
| dns_event_subsampling_map = resolv_get_dns_event_subsampling_map(false); |
| mdns_event_subsampling_map = resolv_get_dns_event_subsampling_map(true); |
| } |
| int nameserverCount() { return nameserverSockAddrs.size(); } |
| int setOptions(const ResolverOptionsParcel& resolverOptions) { |
| customizedTable.clear(); |
| for (const auto& host : resolverOptions.hosts) { |
| if (!host.hostName.empty() && !host.ipAddr.empty()) |
| customizedTable.emplace(host.hostName, host.ipAddr); |
| } |
| |
| if (resolverOptions.tcMode < aidl::android::net::IDnsResolver::TC_MODE_DEFAULT || |
| resolverOptions.tcMode > aidl::android::net::IDnsResolver::TC_MODE_UDP_TCP) { |
| LOG(WARNING) << __func__ << ": netid = " << netid |
| << ", invalid TC mode: " << resolverOptions.tcMode; |
| return -EINVAL; |
| } |
| tc_mode = resolverOptions.tcMode; |
| enforceDnsUid = resolverOptions.enforceDnsUid; |
| return 0; |
| } |
| const unsigned netid; |
| std::unique_ptr<Cache> cache; |
| std::vector<std::string> nameservers; |
| std::vector<IPSockAddr> nameserverSockAddrs; |
| int revision_id = 0; // # times the nameservers have been replaced |
| res_params params{}; |
| res_stats nsstats[MAXNS]{}; |
| std::vector<std::string> search_domains; |
| int wait_for_pending_req_timeout_count = 0; |
| // Map format: ReturnCode:rate_denom |
| std::unordered_map<int, uint32_t> dns_event_subsampling_map; |
| std::unordered_map<int, uint32_t> mdns_event_subsampling_map; |
| DnsStats dnsStats; |
| |
| // Customized hostname/address table will be stored in customizedTable. |
| // If resolverParams.hosts is empty, the existing customized table will be erased. |
| typedef std::multimap<std::string /* hostname */, std::string /* IPv4/IPv6 address */> |
| HostMapping; |
| HostMapping customizedTable = {}; |
| |
| int tc_mode = aidl::android::net::IDnsResolver::TC_MODE_DEFAULT; |
| bool enforceDnsUid = false; |
| std::vector<int32_t> transportTypes; |
| }; |
| |
| /* gets cache associated with a network, or NULL if none exists */ |
| static Cache* find_named_cache_locked(unsigned netid) REQUIRES(cache_mutex); |
| |
| // Return true - if there is a pending request in |cache| matching |key|. |
| // Return false - if no pending request is found matching the key. Optionally |
| // link a new one if parameter append_if_not_found is true. |
| static bool cache_has_pending_request_locked(Cache* cache, const Entry* key, |
| bool append_if_not_found) { |
| if (!cache || !key) return false; |
| |
| Cache::pending_req_info* ri = cache->pending_requests.next; |
| Cache::pending_req_info* prev = &cache->pending_requests; |
| while (ri) { |
| if (ri->hash == key->hash) { |
| return true; |
| } |
| prev = ri; |
| ri = ri->next; |
| } |
| |
| if (append_if_not_found) { |
| ri = (Cache::pending_req_info*)calloc(1, sizeof(Cache::pending_req_info)); |
| if (ri) { |
| ri->hash = key->hash; |
| prev->next = ri; |
| } |
| } |
| return false; |
| } |
| |
| // Notify all threads that the cache entry |key| has become available |
| static void cache_notify_waiting_tid_locked(struct Cache* cache, const Entry* key) { |
| if (!cache || !key) return; |
| |
| Cache::pending_req_info* ri = cache->pending_requests.next; |
| Cache::pending_req_info* prev = &cache->pending_requests; |
| while (ri) { |
| if (ri->hash == key->hash) { |
| // remove item from list and destroy |
| prev->next = ri->next; |
| free(ri); |
| cv.notify_all(); |
| return; |
| } |
| prev = ri; |
| ri = ri->next; |
| } |
| } |
| |
| void _resolv_cache_query_failed(unsigned netid, span<const uint8_t> query, uint32_t flags) { |
| // We should not notify with these flags. |
| if (flags & (ANDROID_RESOLV_NO_CACHE_STORE | ANDROID_RESOLV_NO_CACHE_LOOKUP)) { |
| return; |
| } |
| Entry key[1]; |
| |
| if (!entry_init_key(key, query)) return; |
| |
| std::lock_guard guard(cache_mutex); |
| |
| Cache* cache = find_named_cache_locked(netid); |
| |
| if (cache) { |
| cache_notify_waiting_tid_locked(cache, key); |
| } |
| } |
| |
| static void cache_dump_mru_locked(Cache* cache) { |
| std::string buf = fmt::format("MRU LIST ({:2d}): ", cache->num_entries); |
| for (Entry* e = cache->mru_list.mru_next; e != &cache->mru_list; e = e->mru_next) { |
| fmt::format_to(std::back_inserter(buf), " {}", e->id); |
| } |
| |
| LOG(INFO) << __func__ << ": " << buf; |
| } |
| |
| /* This function tries to find a key within the hash table |
| * In case of success, it will return a *pointer* to the hashed key. |
| * In case of failure, it will return a *pointer* to NULL |
| * |
| * So, the caller must check '*result' to check for success/failure. |
| * |
| * The main idea is that the result can later be used directly in |
| * calls to resolv_cache_add or _resolv_cache_remove as the 'lookup' |
| * parameter. This makes the code simpler and avoids re-searching |
| * for the key position in the htable. |
| * |
| * The result of a lookup_p is only valid until you alter the hash |
| * table. |
| */ |
| static Entry** _cache_lookup_p(Cache* cache, Entry* key) { |
| int index = key->hash % CONFIG_MAX_ENTRIES; |
| Entry** pnode = (Entry**) &cache->entries[index]; |
| |
| while (*pnode != NULL) { |
| Entry* node = *pnode; |
| |
| if (node == NULL) break; |
| |
| if (node->hash == key->hash && entry_equals(node, key)) break; |
| |
| pnode = &node->hlink; |
| } |
| return pnode; |
| } |
| |
| /* Add a new entry to the hash table. 'lookup' must be the |
| * result of an immediate previous failed _lookup_p() call |
| * (i.e. with *lookup == NULL), and 'e' is the pointer to the |
| * newly created entry |
| */ |
| static void _cache_add_p(Cache* cache, Entry** lookup, Entry* e) { |
| *lookup = e; |
| e->id = ++cache->last_id; |
| entry_mru_add(e, &cache->mru_list); |
| cache->num_entries += 1; |
| |
| LOG(INFO) << __func__ << ": entry " << e->id << " added (count=" << cache->num_entries << ")"; |
| } |
| |
| /* Remove an existing entry from the hash table, |
| * 'lookup' must be the result of an immediate previous |
| * and succesful _lookup_p() call. |
| */ |
| static void _cache_remove_p(Cache* cache, Entry** lookup) { |
| Entry* e = *lookup; |
| |
| LOG(INFO) << __func__ << ": entry " << e->id << " removed (count=" << cache->num_entries - 1 |
| << ")"; |
| |
| entry_mru_remove(e); |
| *lookup = e->hlink; |
| entry_free(e); |
| cache->num_entries -= 1; |
| } |
| |
| /* Remove the oldest entry from the hash table. |
| */ |
| static void _cache_remove_oldest(Cache* cache) { |
| Entry* oldest = cache->mru_list.mru_prev; |
| Entry** lookup = _cache_lookup_p(cache, oldest); |
| |
| if (*lookup == NULL) { /* should not happen */ |
| LOG(INFO) << __func__ << ": OLDEST NOT IN HTABLE ?"; |
| return; |
| } |
| LOG(INFO) << __func__ << ": Cache full - removing oldest"; |
| res_pquery({oldest->query, oldest->querylen}); |
| _cache_remove_p(cache, lookup); |
| } |
| |
| /* Remove all expired entries from the hash table. |
| */ |
| static void _cache_remove_expired(Cache* cache) { |
| Entry* e; |
| time_t now = _time_now(); |
| |
| for (e = cache->mru_list.mru_next; e != &cache->mru_list;) { |
| // Entry is old, remove |
| if (now >= e->expires) { |
| Entry** lookup = _cache_lookup_p(cache, e); |
| if (*lookup == NULL) { /* should not happen */ |
| LOG(INFO) << __func__ << ": ENTRY NOT IN HTABLE ?"; |
| return; |
| } |
| e = e->mru_next; |
| _cache_remove_p(cache, lookup); |
| } else { |
| e = e->mru_next; |
| } |
| } |
| } |
| |
| // Get a NetConfig associated with a network, or nullptr if not found. |
| static NetConfig* find_netconfig_locked(unsigned netid) REQUIRES(cache_mutex); |
| |
| ResolvCacheStatus resolv_cache_lookup(unsigned netid, span<const uint8_t> query, |
| span<uint8_t> answer, int* answerlen, uint32_t flags) { |
| // Skip cache lookup, return RESOLV_CACHE_NOTFOUND directly so that it is |
| // possible to cache the answer of this query. |
| // If ANDROID_RESOLV_NO_CACHE_STORE is set, return RESOLV_CACHE_SKIP to skip possible cache |
| // storing. |
| // (b/150371903): ANDROID_RESOLV_NO_CACHE_STORE should imply ANDROID_RESOLV_NO_CACHE_LOOKUP |
| // to avoid side channel attack. |
| if (flags & (ANDROID_RESOLV_NO_CACHE_LOOKUP | ANDROID_RESOLV_NO_CACHE_STORE)) { |
| return flags & ANDROID_RESOLV_NO_CACHE_STORE ? RESOLV_CACHE_SKIP : RESOLV_CACHE_NOTFOUND; |
| } |
| Entry key; |
| Entry** lookup; |
| Entry* e; |
| time_t now; |
| |
| LOG(INFO) << __func__ << ": lookup"; |
| |
| /* we don't cache malformed queries */ |
| if (!entry_init_key(&key, query)) { |
| LOG(INFO) << __func__ << ": unsupported query"; |
| return RESOLV_CACHE_UNSUPPORTED; |
| } |
| /* lookup cache */ |
| std::unique_lock lock(cache_mutex); |
| android::base::ScopedLockAssertion assume_lock(cache_mutex); |
| Cache* cache = find_named_cache_locked(netid); |
| if (cache == nullptr) { |
| return RESOLV_CACHE_UNSUPPORTED; |
| } |
| |
| /* see the description of _lookup_p to understand this. |
| * the function always return a non-NULL pointer. |
| */ |
| lookup = _cache_lookup_p(cache, &key); |
| e = *lookup; |
| |
| if (e == NULL) { |
| LOG(INFO) << __func__ << ": NOT IN CACHE"; |
| |
| if (!cache_has_pending_request_locked(cache, &key, true)) { |
| return RESOLV_CACHE_NOTFOUND; |
| |
| } else { |
| LOG(INFO) << __func__ << ": Waiting for previous request"; |
| // wait until (1) timeout OR |
| // (2) cv is notified AND no pending request matching the |key| |
| // (cv notifier should delete pending request before sending notification.) |
| bool ret = cv.wait_for(lock, std::chrono::seconds(PENDING_REQUEST_TIMEOUT), |
| [netid, &cache, &key]() REQUIRES(cache_mutex) { |
| // Must update cache as it could have been deleted |
| cache = find_named_cache_locked(netid); |
| return !cache_has_pending_request_locked(cache, &key, false); |
| }); |
| if (!cache) { |
| return RESOLV_CACHE_NOTFOUND; |
| } |
| if (ret == false) { |
| NetConfig* info = find_netconfig_locked(netid); |
| if (info != NULL) { |
| info->wait_for_pending_req_timeout_count++; |
| } |
| } |
| lookup = _cache_lookup_p(cache, &key); |
| e = *lookup; |
| if (e == NULL) { |
| return RESOLV_CACHE_NOTFOUND; |
| } |
| } |
| } |
| |
| now = _time_now(); |
| |
| /* remove stale entries here */ |
| if (now >= e->expires) { |
| LOG(INFO) << __func__ << ": NOT IN CACHE (STALE ENTRY " << *lookup << "DISCARDED)"; |
| res_pquery({e->query, e->querylen}); |
| _cache_remove_p(cache, lookup); |
| return RESOLV_CACHE_NOTFOUND; |
| } |
| |
| *answerlen = e->answerlen; |
| if (e->answerlen > answer.size()) { |
| /* NOTE: we return UNSUPPORTED if the answer buffer is too short */ |
| LOG(INFO) << __func__ << ": ANSWER TOO LONG"; |
| return RESOLV_CACHE_UNSUPPORTED; |
| } |
| |
| memcpy(answer.data(), e->answer, e->answerlen); |
| |
| /* bump up this entry to the top of the MRU list */ |
| if (e != cache->mru_list.mru_next) { |
| entry_mru_remove(e); |
| entry_mru_add(e, &cache->mru_list); |
| } |
| |
| LOG(INFO) << __func__ << ": FOUND IN CACHE entry=" << e; |
| return RESOLV_CACHE_FOUND; |
| } |
| |
| int resolv_cache_add(unsigned netid, span<const uint8_t> query, span<const uint8_t> answer) { |
| Entry key[1]; |
| Entry* e; |
| Entry** lookup; |
| uint32_t ttl; |
| Cache* cache = NULL; |
| |
| /* don't assume that the query has already been cached |
| */ |
| if (!entry_init_key(key, query)) { |
| LOG(INFO) << __func__ << ": passed invalid query?"; |
| return -EINVAL; |
| } |
| |
| std::lock_guard guard(cache_mutex); |
| |
| cache = find_named_cache_locked(netid); |
| if (cache == nullptr) { |
| return -ENONET; |
| } |
| |
| lookup = _cache_lookup_p(cache, key); |
| e = *lookup; |
| |
| // Should only happen on ANDROID_RESOLV_NO_CACHE_LOOKUP |
| if (e != NULL) { |
| LOG(INFO) << __func__ << ": ALREADY IN CACHE (" << e << ") ? IGNORING ADD"; |
| cache_notify_waiting_tid_locked(cache, key); |
| return -EEXIST; |
| } |
| |
| if (cache->num_entries >= CONFIG_MAX_ENTRIES) { |
| _cache_remove_expired(cache); |
| if (cache->num_entries >= CONFIG_MAX_ENTRIES) { |
| _cache_remove_oldest(cache); |
| } |
| // TODO: It looks useless, remove below code after having test to prove it. |
| lookup = _cache_lookup_p(cache, key); |
| e = *lookup; |
| if (e != NULL) { |
| LOG(INFO) << __func__ << ": ALREADY IN CACHE (" << e << ") ? IGNORING ADD"; |
| cache_notify_waiting_tid_locked(cache, key); |
| return -EEXIST; |
| } |
| } |
| |
| ttl = answer_getTTL(answer); |
| if (ttl > 0) { |
| e = entry_alloc(key, answer); |
| if (e != NULL) { |
| e->expires = ttl + _time_now(); |
| _cache_add_p(cache, lookup, e); |
| } |
| } |
| |
| cache_dump_mru_locked(cache); |
| cache_notify_waiting_tid_locked(cache, key); |
| |
| return 0; |
| } |
| |
| bool resolv_gethostbyaddr_from_cache(unsigned netid, char domain_name[], size_t domain_name_size, |
| const char* ip_address, int af) { |
| if (domain_name_size > NS_MAXDNAME) { |
| LOG(WARNING) << __func__ << ": invalid domain_name_size " << domain_name_size; |
| return false; |
| } else if (ip_address == nullptr || ip_address[0] == '\0') { |
| LOG(WARNING) << __func__ << ": invalid ip_address"; |
| return false; |
| } else if (af != AF_INET && af != AF_INET6) { |
| LOG(WARNING) << __func__ << ": unsupported AF"; |
| return false; |
| } |
| |
| Cache* cache = nullptr; |
| Entry* node = nullptr; |
| |
| ns_rr rr; |
| ns_msg handle; |
| ns_rr rr_query; |
| |
| struct sockaddr_in sa; |
| struct sockaddr_in6 sa6; |
| char* addr_buf = nullptr; |
| |
| std::lock_guard guard(cache_mutex); |
| |
| cache = find_named_cache_locked(netid); |
| if (cache == nullptr) { |
| return false; |
| } |
| |
| for (node = cache->mru_list.mru_next; node != nullptr && node != &cache->mru_list; |
| node = node->mru_next) { |
| if (node->answer == nullptr) { |
| continue; |
| } |
| |
| memset(&handle, 0, sizeof(handle)); |
| |
| if (ns_initparse(node->answer, node->answerlen, &handle) < 0) { |
| continue; |
| } |
| |
| for (int n = 0; n < ns_msg_count(handle, ns_s_an); n++) { |
| memset(&rr, 0, sizeof(rr)); |
| |
| if (ns_parserr(&handle, ns_s_an, n, &rr)) { |
| continue; |
| } |
| |
| if (ns_rr_type(rr) == ns_t_a && af == AF_INET) { |
| addr_buf = (char*)&(sa.sin_addr); |
| } else if (ns_rr_type(rr) == ns_t_aaaa && af == AF_INET6) { |
| addr_buf = (char*)&(sa6.sin6_addr); |
| } else { |
| continue; |
| } |
| |
| if (inet_pton(af, ip_address, addr_buf) != 1) { |
| LOG(WARNING) << __func__ << ": inet_pton() fail"; |
| return false; |
| } |
| |
| if (memcmp(ns_rr_rdata(rr), addr_buf, ns_rr_rdlen(rr)) == 0) { |
| int query_count = ns_msg_count(handle, ns_s_qd); |
| for (int i = 0; i < query_count; i++) { |
| memset(&rr_query, 0, sizeof(rr_query)); |
| if (ns_parserr(&handle, ns_s_qd, i, &rr_query)) { |
| continue; |
| } |
| strlcpy(domain_name, ns_rr_name(rr_query), domain_name_size); |
| if (domain_name[0] != '\0') { |
| return true; |
| } |
| } |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| static std::unordered_map<unsigned, std::unique_ptr<NetConfig>> sNetConfigMap |
| GUARDED_BY(cache_mutex); |
| |
| // Clears nameservers set for |netconfig| and clears the stats |
| static void free_nameservers_locked(NetConfig* netconfig); |
| // Order-insensitive comparison for the two set of servers. |
| static bool resolv_is_nameservers_equal(const std::vector<std::string>& oldServers, |
| const std::vector<std::string>& newServers); |
| // clears the stats samples contained withing the given netconfig. |
| static void res_cache_clear_stats_locked(NetConfig* netconfig); |
| |
| // public API for netd to query if name server is set on specific netid |
| bool resolv_has_nameservers(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* info = find_netconfig_locked(netid); |
| return (info != nullptr) && (info->nameserverCount() > 0); |
| } |
| |
| int resolv_create_cache_for_net(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| if (sNetConfigMap.find(netid) != sNetConfigMap.end()) { |
| LOG(ERROR) << __func__ << ": Cache is already created, netId: " << netid; |
| return -EEXIST; |
| } |
| |
| sNetConfigMap[netid] = std::make_unique<NetConfig>(netid); |
| |
| return 0; |
| } |
| |
| void resolv_delete_cache_for_net(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| sNetConfigMap.erase(netid); |
| } |
| |
| int resolv_flush_cache_for_net(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| if (netconfig == nullptr) { |
| return -ENONET; |
| } |
| netconfig->cache->flush(); |
| |
| // Also clear the NS statistics. |
| res_cache_clear_stats_locked(netconfig); |
| return 0; |
| } |
| |
| std::vector<unsigned> resolv_list_caches() { |
| std::lock_guard guard(cache_mutex); |
| std::vector<unsigned> result; |
| result.reserve(sNetConfigMap.size()); |
| for (const auto& [netId, _] : sNetConfigMap) { |
| result.push_back(netId); |
| } |
| return result; |
| } |
| |
| static Cache* find_named_cache_locked(unsigned netid) { |
| NetConfig* info = find_netconfig_locked(netid); |
| if (info != nullptr) return info->cache.get(); |
| return nullptr; |
| } |
| |
| static NetConfig* find_netconfig_locked(unsigned netid) { |
| if (auto it = sNetConfigMap.find(netid); it != sNetConfigMap.end()) { |
| return it->second.get(); |
| } |
| return nullptr; |
| } |
| |
| static void resolv_set_experiment_params(res_params* params) { |
| if (params->retry_count == 0) { |
| params->retry_count = getExperimentFlagInt("retry_count", RES_DFLRETRY); |
| } |
| |
| if (params->base_timeout_msec == 0) { |
| params->base_timeout_msec = |
| getExperimentFlagInt("retransmission_time_interval", RES_TIMEOUT); |
| } |
| } |
| |
| android::net::NetworkType resolv_get_network_types_for_net(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| if (netconfig == nullptr) return android::net::NT_UNKNOWN; |
| return convert_network_type(netconfig->transportTypes); |
| } |
| |
| bool is_mdns_supported_transport_types(const std::vector<int32_t>& transportTypes) { |
| for (const auto& tp : transportTypes) { |
| if (tp == IDnsResolver::TRANSPORT_CELLULAR || tp == IDnsResolver::TRANSPORT_VPN) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool is_mdns_supported_network(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| if (netconfig == nullptr) return false; |
| return is_mdns_supported_transport_types(netconfig->transportTypes); |
| } |
| |
| namespace { |
| |
| // Returns valid domains without duplicates which are limited to max size |MAXDNSRCH|. |
| std::vector<std::string> filter_domains(const std::vector<std::string>& domains) { |
| std::set<std::string> tmp_set; |
| std::vector<std::string> res; |
| |
| std::copy_if(domains.begin(), domains.end(), std::back_inserter(res), |
| [&tmp_set](const std::string& str) { |
| return !(str.size() > MAXDNSRCHPATH - 1) && (tmp_set.insert(str).second); |
| }); |
| if (res.size() > MAXDNSRCH) { |
| LOG(WARNING) << __func__ << ": valid domains=" << res.size() |
| << ", but MAXDNSRCH=" << MAXDNSRCH; |
| res.resize(MAXDNSRCH); |
| } |
| return res; |
| } |
| |
| std::vector<std::string> filter_nameservers(const std::vector<std::string>& servers) { |
| std::vector<std::string> res = servers; |
| if (res.size() > MAXNS) { |
| LOG(WARNING) << __func__ << ": too many servers: " << res.size(); |
| res.resize(MAXNS); |
| } |
| return res; |
| } |
| |
| bool isValidServer(const std::string& server) { |
| const addrinfo hints = { |
| .ai_family = AF_UNSPEC, |
| .ai_socktype = SOCK_DGRAM, |
| }; |
| addrinfo* result = nullptr; |
| if (int err = getaddrinfo_numeric(server.c_str(), "53", hints, &result); err != 0) { |
| LOG(WARNING) << __func__ << ": getaddrinfo_numeric(" << server |
| << ") = " << gai_strerror(err); |
| return false; |
| } |
| freeaddrinfo(result); |
| return true; |
| } |
| |
| } // namespace |
| |
| std::vector<std::string> getCustomizedTableByName(const size_t netid, const char* hostname) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| |
| std::vector<std::string> result; |
| if (netconfig != nullptr) { |
| const auto& hosts = netconfig->customizedTable.equal_range(hostname); |
| for (auto i = hosts.first; i != hosts.second; ++i) { |
| result.push_back(i->second); |
| } |
| } |
| return result; |
| } |
| |
| int resolv_set_nameservers(unsigned netid, const std::vector<std::string>& servers, |
| const std::vector<std::string>& domains, const res_params& params, |
| const std::optional<ResolverOptionsParcel> optionalResolverOptions, |
| const std::vector<int32_t>& transportTypes) { |
| std::vector<std::string> nameservers = filter_nameservers(servers); |
| const int numservers = static_cast<int>(nameservers.size()); |
| |
| LOG(INFO) << __func__ << ": netId = " << netid << ", numservers = " << numservers; |
| |
| // Parse the addresses before actually locking or changing any state, in case there is an error. |
| // As a side effect this also reduces the time the lock is kept. |
| std::vector<IPSockAddr> ipSockAddrs; |
| ipSockAddrs.reserve(nameservers.size()); |
| for (const auto& server : nameservers) { |
| if (!isValidServer(server)) return -EINVAL; |
| ipSockAddrs.push_back(IPSockAddr::toIPSockAddr(server, 53)); |
| } |
| |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| |
| if (netconfig == nullptr) return -ENONET; |
| |
| uint8_t old_max_samples = netconfig->params.max_samples; |
| netconfig->params = params; |
| resolv_set_experiment_params(&netconfig->params); |
| if (!resolv_is_nameservers_equal(netconfig->nameservers, nameservers)) { |
| // free current before adding new |
| free_nameservers_locked(netconfig); |
| netconfig->nameservers = std::move(nameservers); |
| for (int i = 0; i < numservers; i++) { |
| LOG(INFO) << __func__ << ": netid = " << netid |
| << ", addr = " << netconfig->nameservers[i]; |
| } |
| netconfig->nameserverSockAddrs = std::move(ipSockAddrs); |
| } else { |
| if (netconfig->params.max_samples != old_max_samples) { |
| // If the maximum number of samples changes, the overhead of keeping the most recent |
| // samples around is not considered worth the effort, so they are cleared instead. |
| // All other parameters do not affect shared state: Changing these parameters does |
| // not invalidate the samples, as they only affect aggregation and the conditions |
| // under which servers are considered usable. |
| res_cache_clear_stats_locked(netconfig); |
| } |
| } |
| |
| // Always update the search paths. Cache-flushing however is not necessary, |
| // since the stored cache entries do contain the domain, not just the host name. |
| netconfig->search_domains = filter_domains(domains); |
| |
| // Setup stats for cleartext dns servers. |
| if (!netconfig->dnsStats.setAddrs(netconfig->nameserverSockAddrs, PROTO_TCP) || |
| !netconfig->dnsStats.setAddrs(netconfig->nameserverSockAddrs, PROTO_UDP)) { |
| LOG(WARNING) << __func__ << ": netid = " << netid << ", failed to set dns stats"; |
| return -EINVAL; |
| } |
| netconfig->transportTypes = transportTypes; |
| if (optionalResolverOptions.has_value()) { |
| const ResolverOptionsParcel& resolverOptions = optionalResolverOptions.value(); |
| return netconfig->setOptions(resolverOptions); |
| } |
| return 0; |
| } |
| |
| int resolv_set_options(unsigned netid, const ResolverOptionsParcel& options) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| |
| if (netconfig == nullptr) return -ENONET; |
| return netconfig->setOptions(options); |
| } |
| |
| static bool resolv_is_nameservers_equal(const std::vector<std::string>& oldServers, |
| const std::vector<std::string>& newServers) { |
| const std::set<std::string> olds(oldServers.begin(), oldServers.end()); |
| const std::set<std::string> news(newServers.begin(), newServers.end()); |
| |
| // TODO: this is incorrect if the list of current or previous nameservers |
| // contains duplicates. This does not really matter because the framework |
| // filters out duplicates, but we should probably fix it. It's also |
| // insensitive to the order of the nameservers; we should probably fix that |
| // too. |
| return olds == news; |
| } |
| |
| static void free_nameservers_locked(NetConfig* netconfig) { |
| netconfig->nameservers.clear(); |
| netconfig->nameserverSockAddrs.clear(); |
| res_cache_clear_stats_locked(netconfig); |
| } |
| |
| void resolv_populate_res_for_net(ResState* statp) { |
| if (statp == nullptr) { |
| return; |
| } |
| LOG(INFO) << __func__ << ": netid=" << statp->netid; |
| |
| std::lock_guard guard(cache_mutex); |
| NetConfig* info = find_netconfig_locked(statp->netid); |
| if (info == nullptr) return; |
| |
| const bool sortNameservers = Experiments::getInstance()->getFlag("sort_nameservers", 0); |
| statp->sort_nameservers = sortNameservers; |
| statp->nsaddrs = sortNameservers ? info->dnsStats.getSortedServers(PROTO_UDP) |
| : info->nameserverSockAddrs; |
| statp->search_domains = info->search_domains; |
| statp->tc_mode = info->tc_mode; |
| statp->enforce_dns_uid = info->enforceDnsUid; |
| } |
| |
| /* Resolver reachability statistics. */ |
| |
| static void res_cache_add_stats_sample_locked(res_stats* stats, const res_sample& sample, |
| int max_samples) { |
| // Note: This function expects max_samples > 0, otherwise a (harmless) modification of the |
| // allocated but supposedly unused memory for samples[0] will happen |
| LOG(INFO) << __func__ << ": adding sample to stats, next = " << unsigned(stats->sample_next) |
| << ", count = " << unsigned(stats->sample_count); |
| stats->samples[stats->sample_next] = sample; |
| if (stats->sample_count < max_samples) { |
| ++stats->sample_count; |
| } |
| if (++stats->sample_next >= max_samples) { |
| stats->sample_next = 0; |
| } |
| } |
| |
| static void res_cache_clear_stats_locked(NetConfig* netconfig) { |
| for (int i = 0; i < MAXNS; ++i) { |
| netconfig->nsstats[i].sample_count = 0; |
| netconfig->nsstats[i].sample_next = 0; |
| } |
| |
| // Increment the revision id to ensure that sample state is not written back if the |
| // servers change; in theory it would suffice to do so only if the servers or |
| // max_samples actually change, in practice the overhead of checking is higher than the |
| // cost, and overflows are unlikely. |
| ++netconfig->revision_id; |
| } |
| |
| int android_net_res_stats_get_info_for_net(unsigned netid, int* nscount, |
| struct sockaddr_storage servers[MAXNS], int* dcount, |
| char domains[MAXDNSRCH][MAXDNSRCHPATH], |
| res_params* params, struct res_stats stats[MAXNS], |
| int* wait_for_pending_req_timeout_count) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* info = find_netconfig_locked(netid); |
| if (!info) return -1; |
| |
| const int num = info->nameserverCount(); |
| if (num > MAXNS) { |
| LOG(INFO) << __func__ << ": nscount " << num << " > MAXNS " << MAXNS; |
| errno = EFAULT; |
| return -1; |
| } |
| |
| for (int i = 0; i < num; i++) { |
| servers[i] = info->nameserverSockAddrs[i]; |
| stats[i] = info->nsstats[i]; |
| } |
| |
| for (size_t i = 0; i < info->search_domains.size(); i++) { |
| strlcpy(domains[i], info->search_domains[i].c_str(), MAXDNSRCHPATH); |
| } |
| |
| *nscount = num; |
| *dcount = static_cast<int>(info->search_domains.size()); |
| *params = info->params; |
| *wait_for_pending_req_timeout_count = info->wait_for_pending_req_timeout_count; |
| |
| return info->revision_id; |
| } |
| |
| std::vector<std::string> resolv_cache_dump_subsampling_map(unsigned netid, bool is_mdns) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| if (netconfig == nullptr) return {}; |
| std::vector<std::string> result; |
| const auto& subsampling_map = (!is_mdns) ? netconfig->dns_event_subsampling_map |
| : netconfig->mdns_event_subsampling_map; |
| result.reserve(subsampling_map.size()); |
| for (const auto& [return_code, rate_denom] : subsampling_map) { |
| result.push_back(fmt::format("{}:{}", |
| (return_code == DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY) |
| ? "default" |
| : std::to_string(return_code), |
| rate_denom)); |
| } |
| return result; |
| } |
| |
| // Decides whether an event should be sampled using a random number generator and |
| // a sampling factor derived from the netid and the return code. |
| // |
| // Returns the subsampling rate if the event should be sampled, or 0 if it should be discarded. |
| uint32_t resolv_cache_get_subsampling_denom(unsigned netid, int return_code, bool is_mdns) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* netconfig = find_netconfig_locked(netid); |
| if (netconfig == nullptr) return 0; // Don't log anything at all. |
| const auto& subsampling_map = (!is_mdns) ? netconfig->dns_event_subsampling_map |
| : netconfig->mdns_event_subsampling_map; |
| auto search_returnCode = subsampling_map.find(return_code); |
| uint32_t denom; |
| if (search_returnCode != subsampling_map.end()) { |
| denom = search_returnCode->second; |
| } else { |
| auto search_default = subsampling_map.find(DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY); |
| denom = (search_default == subsampling_map.end()) ? 0 : search_default->second; |
| } |
| return denom; |
| } |
| |
| int resolv_cache_get_resolver_stats(unsigned netid, res_params* params, res_stats stats[MAXNS], |
| const std::vector<IPSockAddr>& serverSockAddrs) { |
| std::lock_guard guard(cache_mutex); |
| NetConfig* info = find_netconfig_locked(netid); |
| if (!info) return -1; |
| |
| for (size_t i = 0; i < serverSockAddrs.size(); i++) { |
| for (size_t j = 0; j < info->nameserverSockAddrs.size(); j++) { |
| // Should never happen. Just in case because of the fix-sized array |stats|. |
| if (j >= MAXNS) { |
| LOG(WARNING) << __func__ << ": unexpected size " << j; |
| return -1; |
| } |
| |
| // It's possible that the server is not found, e.g. when a new list of nameservers |
| // is updated to the NetConfig just after this look up thread being populated. |
| // Keep the server valid as-is (by means of keeping stats[i] unset), but we should |
| // think about if there's a better way. |
| if (info->nameserverSockAddrs[j] == serverSockAddrs[i]) { |
| stats[i] = info->nsstats[j]; |
| break; |
| } |
| } |
| } |
| |
| *params = info->params; |
| return info->revision_id; |
| } |
| |
| void resolv_cache_add_resolver_stats_sample(unsigned netid, int revision_id, |
| const IPSockAddr& serverSockAddr, |
| const res_sample& sample, int max_samples) { |
| if (max_samples <= 0) return; |
| |
| std::lock_guard guard(cache_mutex); |
| NetConfig* info = find_netconfig_locked(netid); |
| |
| if (info && info->revision_id == revision_id) { |
| const int serverNum = std::min(MAXNS, static_cast<int>(info->nameserverSockAddrs.size())); |
| for (int ns = 0; ns < serverNum; ns++) { |
| if (serverSockAddr == info->nameserverSockAddrs[ns]) { |
| res_cache_add_stats_sample_locked(&info->nsstats[ns], sample, max_samples); |
| return; |
| } |
| } |
| } |
| } |
| |
| bool has_named_cache(unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| return find_named_cache_locked(netid) != nullptr; |
| } |
| |
| int resolv_cache_get_expiration(unsigned netid, span<const uint8_t> query, time_t* expiration) { |
| Entry key; |
| *expiration = -1; |
| |
| // A malformed query is not allowed. |
| if (!entry_init_key(&key, query)) { |
| LOG(WARNING) << __func__ << ": unsupported query"; |
| return -EINVAL; |
| } |
| |
| // lookup cache. |
| Cache* cache; |
| std::lock_guard guard(cache_mutex); |
| if (cache = find_named_cache_locked(netid); cache == nullptr) { |
| LOG(WARNING) << __func__ << ": cache not created in the network " << netid; |
| return -ENONET; |
| } |
| Entry** lookup = _cache_lookup_p(cache, &key); |
| Entry* e = *lookup; |
| if (e == NULL) { |
| LOG(WARNING) << __func__ << ": not in cache"; |
| return -ENODATA; |
| } |
| |
| if (_time_now() >= e->expires) { |
| LOG(WARNING) << __func__ << ": entry expired"; |
| return -ENODATA; |
| } |
| |
| *expiration = e->expires; |
| return 0; |
| } |
| |
| static const char* protocol_to_str(const Protocol proto) { |
| switch (proto) { |
| case PROTO_UDP: |
| return "UDP"; |
| case PROTO_TCP: |
| return "TCP"; |
| case PROTO_DOT: |
| return "DOT"; |
| case PROTO_DOH: |
| return "DOH"; |
| case PROTO_MDNS: |
| return "MDNS"; |
| default: |
| return "UNKNOWN"; |
| } |
| } |
| |
| int resolv_stats_set_addrs(unsigned netid, Protocol proto, const std::vector<std::string>& addrs, |
| int port) { |
| std::lock_guard guard(cache_mutex); |
| const auto info = find_netconfig_locked(netid); |
| |
| if (info == nullptr) return -ENONET; |
| |
| std::vector<IPSockAddr> sockAddrs; |
| sockAddrs.reserve(addrs.size()); |
| for (const auto& addr : addrs) { |
| sockAddrs.push_back(IPSockAddr::toIPSockAddr(addr, port)); |
| } |
| |
| if (!info->dnsStats.setAddrs(sockAddrs, proto)) { |
| LOG(WARNING) << __func__ << ": netid = " << netid << ", failed to set " |
| << protocol_to_str(proto) << " stats"; |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| bool resolv_stats_add(unsigned netid, const android::netdutils::IPSockAddr& server, |
| const DnsQueryEvent* record) { |
| if (record == nullptr) return false; |
| |
| std::lock_guard guard(cache_mutex); |
| if (const auto info = find_netconfig_locked(netid); info != nullptr) { |
| return info->dnsStats.addStats(server, *record); |
| } |
| return false; |
| } |
| |
| static const char* tc_mode_to_str(const int mode) { |
| switch (mode) { |
| case aidl::android::net::IDnsResolver::TC_MODE_DEFAULT: |
| return "default"; |
| case aidl::android::net::IDnsResolver::TC_MODE_UDP_TCP: |
| return "UDP_TCP"; |
| default: |
| return "unknown"; |
| } |
| } |
| |
| static android::net::NetworkType to_stats_network_type(int32_t mainType, bool withVpn) { |
| switch (mainType) { |
| case IDnsResolver::TRANSPORT_CELLULAR: |
| return withVpn ? android::net::NT_CELLULAR_VPN : android::net::NT_CELLULAR; |
| case IDnsResolver::TRANSPORT_WIFI: |
| return withVpn ? android::net::NT_WIFI_VPN : android::net::NT_WIFI; |
| case IDnsResolver::TRANSPORT_BLUETOOTH: |
| return withVpn ? android::net::NT_BLUETOOTH_VPN : android::net::NT_BLUETOOTH; |
| case IDnsResolver::TRANSPORT_ETHERNET: |
| return withVpn ? android::net::NT_ETHERNET_VPN : android::net::NT_ETHERNET; |
| case IDnsResolver::TRANSPORT_VPN: |
| return withVpn ? android::net::NT_UNKNOWN : android::net::NT_VPN; |
| case IDnsResolver::TRANSPORT_WIFI_AWARE: |
| return withVpn ? android::net::NT_UNKNOWN : android::net::NT_WIFI_AWARE; |
| case IDnsResolver::TRANSPORT_LOWPAN: |
| return withVpn ? android::net::NT_UNKNOWN : android::net::NT_LOWPAN; |
| default: |
| return android::net::NT_UNKNOWN; |
| } |
| } |
| |
| android::net::NetworkType convert_network_type(const std::vector<int32_t>& transportTypes) { |
| // The valid transportTypes size is 1 to 3. |
| if (transportTypes.size() > 3 || transportTypes.size() == 0) return android::net::NT_UNKNOWN; |
| // TransportTypes size == 1, map the type to stats network type directly. |
| if (transportTypes.size() == 1) return to_stats_network_type(transportTypes[0], false); |
| // TransportTypes size == 3, only cellular + wifi + vpn is valid. |
| if (transportTypes.size() == 3) { |
| std::vector<int32_t> sortedTransTypes = transportTypes; |
| std::sort(sortedTransTypes.begin(), sortedTransTypes.end()); |
| if (sortedTransTypes != std::vector<int32_t>{IDnsResolver::TRANSPORT_CELLULAR, |
| IDnsResolver::TRANSPORT_WIFI, |
| IDnsResolver::TRANSPORT_VPN}) { |
| return android::net::NT_UNKNOWN; |
| } |
| return android::net::NT_WIFI_CELLULAR_VPN; |
| } |
| // TransportTypes size == 2, it shoud be 1 main type + vpn type. |
| // Otherwise, consider it as UNKNOWN. |
| bool hasVpn = false; |
| int32_t mainType = IDnsResolver::TRANSPORT_UNKNOWN; |
| for (const auto& transportType : transportTypes) { |
| if (transportType == IDnsResolver::TRANSPORT_VPN) { |
| hasVpn = true; |
| continue; |
| } |
| mainType = transportType; |
| } |
| return hasVpn ? to_stats_network_type(mainType, true) : android::net::NT_UNKNOWN; |
| } |
| |
| static const char* transport_type_to_str(const std::vector<int32_t>& transportTypes) { |
| switch (convert_network_type(transportTypes)) { |
| case android::net::NT_CELLULAR: |
| return "CELLULAR"; |
| case android::net::NT_WIFI: |
| return "WIFI"; |
| case android::net::NT_BLUETOOTH: |
| return "BLUETOOTH"; |
| case android::net::NT_ETHERNET: |
| return "ETHERNET"; |
| case android::net::NT_VPN: |
| return "VPN"; |
| case android::net::NT_WIFI_AWARE: |
| return "WIFI_AWARE"; |
| case android::net::NT_LOWPAN: |
| return "LOWPAN"; |
| case android::net::NT_CELLULAR_VPN: |
| return "CELLULAR_VPN"; |
| case android::net::NT_WIFI_VPN: |
| return "WIFI_VPN"; |
| case android::net::NT_BLUETOOTH_VPN: |
| return "BLUETOOTH_VPN"; |
| case android::net::NT_ETHERNET_VPN: |
| return "ETHERNET_VPN"; |
| case android::net::NT_WIFI_CELLULAR_VPN: |
| return "WIFI_CELLULAR_VPN"; |
| default: |
| return "UNKNOWN"; |
| } |
| } |
| |
| void resolv_netconfig_dump(DumpWriter& dw, unsigned netid) { |
| std::lock_guard guard(cache_mutex); |
| if (const auto info = find_netconfig_locked(netid); info != nullptr) { |
| info->dnsStats.dump(dw); |
| // TODO: dump info->hosts |
| dw.println("TC mode: %s", tc_mode_to_str(info->tc_mode)); |
| dw.println("TransportType: %s", transport_type_to_str(info->transportTypes)); |
| } |
| } |