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2047 lines
68 KiB
2047 lines
68 KiB
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#define LOG_TAG "resolv"
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#include "resolv_cache.h"
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#include <resolv.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <algorithm>
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#include <mutex>
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#include <set>
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#include <string>
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#include <unordered_map>
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#include <vector>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <errno.h>
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#include <linux/if.h>
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#include <net/if.h>
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#include <netdb.h>
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#include <aidl/android/net/IDnsResolver.h>
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#include <android-base/logging.h>
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#include <android-base/parseint.h>
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#include <android-base/stringprintf.h>
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#include <android-base/strings.h>
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#include <android-base/thread_annotations.h>
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#include <android/multinetwork.h> // ResNsendFlags
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#include <server_configurable_flags/get_flags.h>
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#include "DnsStats.h"
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#include "Experiments.h"
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#include "res_comp.h"
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#include "res_debug.h"
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#include "resolv_private.h"
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#include "util.h"
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using aidl::android::net::IDnsResolver;
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using aidl::android::net::ResolverOptionsParcel;
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using android::base::StringAppendF;
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using android::net::DnsQueryEvent;
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using android::net::DnsStats;
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using android::net::Experiments;
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using android::net::PROTO_DOT;
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using android::net::PROTO_TCP;
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using android::net::PROTO_UDP;
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using android::netdutils::DumpWriter;
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using android::netdutils::IPSockAddr;
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/* This code implements a small and *simple* DNS resolver cache.
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*
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* It is only used to cache DNS answers for a time defined by the smallest TTL
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* among the answer records in order to reduce DNS traffic. It is not supposed
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* to be a full DNS cache, since we plan to implement that in the future in a
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* dedicated process running on the system.
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*
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* Note that its design is kept simple very intentionally, i.e.:
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*
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* - it takes raw DNS query packet data as input, and returns raw DNS
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* answer packet data as output
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*
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* (this means that two similar queries that encode the DNS name
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* differently will be treated distinctly).
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*
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* the smallest TTL value among the answer records are used as the time
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* to keep an answer in the cache.
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*
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* this is bad, but we absolutely want to avoid parsing the answer packets
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* (and should be solved by the later full DNS cache process).
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*
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* - the implementation is just a (query-data) => (answer-data) hash table
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* with a trivial least-recently-used expiration policy.
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*
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* Doing this keeps the code simple and avoids to deal with a lot of things
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* that a full DNS cache is expected to do.
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*
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* The API is also very simple:
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*
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* - the client calls resolv_cache_lookup() before performing a query
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*
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* If the function returns RESOLV_CACHE_FOUND, a copy of the answer data
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* has been copied into the client-provided answer buffer.
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*
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* If the function returns RESOLV_CACHE_NOTFOUND, the client should perform
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* a request normally, *then* call resolv_cache_add() to add the received
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* answer to the cache.
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*
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* If the function returns RESOLV_CACHE_UNSUPPORTED, the client should
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* perform a request normally, and *not* call resolv_cache_add()
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*
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* Note that RESOLV_CACHE_UNSUPPORTED is also returned if the answer buffer
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* is too short to accomodate the cached result.
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*/
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/* Default number of entries kept in the cache. This value has been
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* determined by browsing through various sites and counting the number
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* of corresponding requests. Keep in mind that our framework is currently
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* performing two requests per name lookup (one for IPv4, the other for IPv6)
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*
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* www.google.com 4
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* www.ysearch.com 6
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* www.amazon.com 8
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* www.nytimes.com 22
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* www.espn.com 28
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* www.msn.com 28
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* www.lemonde.fr 35
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*
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* (determined in 2009-2-17 from Paris, France, results may vary depending
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* on location)
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*
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* most high-level websites use lots of media/ad servers with different names
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* but these are generally reused when browsing through the site.
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*
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* As such, a value of 64 should be relatively comfortable at the moment.
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*
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* ******************************************
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* * NOTE - this has changed.
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* * 1) we've added IPv6 support so each dns query results in 2 responses
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* * 2) we've made this a system-wide cache, so the cost is less (it's not
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* * duplicated in each process) and the need is greater (more processes
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* * making different requests).
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* * Upping by 2x for IPv6
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* * Upping by another 5x for the centralized nature
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* *****************************************
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*/
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const int CONFIG_MAX_ENTRIES = 64 * 2 * 5;
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constexpr int DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY = -1;
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static time_t _time_now(void) {
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struct timeval tv;
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gettimeofday(&tv, NULL);
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return tv.tv_sec;
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}
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/* reminder: the general format of a DNS packet is the following:
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*
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* HEADER (12 bytes)
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* QUESTION (variable)
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* ANSWER (variable)
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* AUTHORITY (variable)
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* ADDITIONNAL (variable)
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*
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* the HEADER is made of:
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*
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* ID : 16 : 16-bit unique query identification field
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*
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* QR : 1 : set to 0 for queries, and 1 for responses
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* Opcode : 4 : set to 0 for queries
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* AA : 1 : set to 0 for queries
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* TC : 1 : truncation flag, will be set to 0 in queries
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* RD : 1 : recursion desired
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*
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* RA : 1 : recursion available (0 in queries)
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* Z : 3 : three reserved zero bits
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* RCODE : 4 : response code (always 0=NOERROR in queries)
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*
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* QDCount: 16 : question count
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* ANCount: 16 : Answer count (0 in queries)
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* NSCount: 16: Authority Record count (0 in queries)
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* ARCount: 16: Additionnal Record count (0 in queries)
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*
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* the QUESTION is made of QDCount Question Record (QRs)
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* the ANSWER is made of ANCount RRs
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* the AUTHORITY is made of NSCount RRs
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* the ADDITIONNAL is made of ARCount RRs
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*
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* Each Question Record (QR) is made of:
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*
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* QNAME : variable : Query DNS NAME
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* TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255)
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* CLASS : 16 : class of query (IN=1)
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*
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* Each Resource Record (RR) is made of:
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*
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* NAME : variable : DNS NAME
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* TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255)
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* CLASS : 16 : class of query (IN=1)
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* TTL : 32 : seconds to cache this RR (0=none)
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* RDLENGTH: 16 : size of RDDATA in bytes
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* RDDATA : variable : RR data (depends on TYPE)
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*
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* Each QNAME contains a domain name encoded as a sequence of 'labels'
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* terminated by a zero. Each label has the following format:
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*
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* LEN : 8 : lenght of label (MUST be < 64)
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* NAME : 8*LEN : label length (must exclude dots)
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*
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* A value of 0 in the encoding is interpreted as the 'root' domain and
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* terminates the encoding. So 'www.android.com' will be encoded as:
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*
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* <3>www<7>android<3>com<0>
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*
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* Where <n> represents the byte with value 'n'
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*
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* Each NAME reflects the QNAME of the question, but has a slightly more
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* complex encoding in order to provide message compression. This is achieved
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* by using a 2-byte pointer, with format:
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*
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* TYPE : 2 : 0b11 to indicate a pointer, 0b01 and 0b10 are reserved
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* OFFSET : 14 : offset to another part of the DNS packet
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*
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* The offset is relative to the start of the DNS packet and must point
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* A pointer terminates the encoding.
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*
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* The NAME can be encoded in one of the following formats:
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*
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* - a sequence of simple labels terminated by 0 (like QNAMEs)
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* - a single pointer
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* - a sequence of simple labels terminated by a pointer
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*
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* A pointer shall always point to either a pointer of a sequence of
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* labels (which can themselves be terminated by either a 0 or a pointer)
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*
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* The expanded length of a given domain name should not exceed 255 bytes.
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*
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* NOTE: we don't parse the answer packets, so don't need to deal with NAME
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* records, only QNAMEs.
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*/
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#define DNS_HEADER_SIZE 12
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#define DNS_TYPE_A "\00\01" /* big-endian decimal 1 */
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#define DNS_TYPE_PTR "\00\014" /* big-endian decimal 12 */
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#define DNS_TYPE_MX "\00\017" /* big-endian decimal 15 */
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#define DNS_TYPE_AAAA "\00\034" /* big-endian decimal 28 */
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#define DNS_TYPE_ALL "\00\0377" /* big-endian decimal 255 */
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#define DNS_CLASS_IN "\00\01" /* big-endian decimal 1 */
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struct DnsPacket {
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const uint8_t* base;
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const uint8_t* end;
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const uint8_t* cursor;
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};
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static uint8_t res_tolower(uint8_t c) {
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return (c >= 'A' && c <= 'Z') ? (c | 0x20) : c;
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}
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static int res_memcasecmp(const unsigned char *s1, const unsigned char *s2, size_t len) {
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for (size_t i = 0; i < len; i++) {
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int ch1 = *s1++;
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int ch2 = *s2++;
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int d = res_tolower(ch1) - res_tolower(ch2);
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if (d != 0) {
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return d;
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}
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}
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return 0;
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}
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static void _dnsPacket_init(DnsPacket* packet, const uint8_t* buff, int bufflen) {
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packet->base = buff;
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packet->end = buff + bufflen;
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packet->cursor = buff;
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}
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static void _dnsPacket_rewind(DnsPacket* packet) {
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packet->cursor = packet->base;
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}
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static void _dnsPacket_skip(DnsPacket* packet, int count) {
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const uint8_t* p = packet->cursor + count;
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if (p > packet->end) p = packet->end;
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packet->cursor = p;
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}
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static int _dnsPacket_readInt16(DnsPacket* packet) {
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const uint8_t* p = packet->cursor;
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if (p + 2 > packet->end) return -1;
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packet->cursor = p + 2;
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return (p[0] << 8) | p[1];
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}
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/** QUERY CHECKING **/
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/* check bytes in a dns packet. returns 1 on success, 0 on failure.
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* the cursor is only advanced in the case of success
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*/
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static int _dnsPacket_checkBytes(DnsPacket* packet, int numBytes, const void* bytes) {
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const uint8_t* p = packet->cursor;
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if (p + numBytes > packet->end) return 0;
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if (memcmp(p, bytes, numBytes) != 0) return 0;
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packet->cursor = p + numBytes;
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return 1;
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}
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/* parse and skip a given QNAME stored in a query packet,
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* from the current cursor position. returns 1 on success,
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* or 0 for malformed data.
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*/
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static int _dnsPacket_checkQName(DnsPacket* packet) {
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const uint8_t* p = packet->cursor;
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const uint8_t* end = packet->end;
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for (;;) {
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int c;
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if (p >= end) break;
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c = *p++;
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if (c == 0) {
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packet->cursor = p;
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return 1;
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}
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/* we don't expect label compression in QNAMEs */
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if (c >= 64) break;
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p += c;
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/* we rely on the bound check at the start
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* of the loop here */
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}
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/* malformed data */
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LOG(INFO) << __func__ << ": malformed QNAME";
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return 0;
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}
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/* parse and skip a given QR stored in a packet.
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* returns 1 on success, and 0 on failure
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*/
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static int _dnsPacket_checkQR(DnsPacket* packet) {
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if (!_dnsPacket_checkQName(packet)) return 0;
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/* TYPE must be one of the things we support */
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if (!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_A) &&
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!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_PTR) &&
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!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_MX) &&
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!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_AAAA) &&
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!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_ALL)) {
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LOG(INFO) << __func__ << ": unsupported TYPE";
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return 0;
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}
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/* CLASS must be IN */
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if (!_dnsPacket_checkBytes(packet, 2, DNS_CLASS_IN)) {
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LOG(INFO) << __func__ << ": unsupported CLASS";
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return 0;
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}
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return 1;
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}
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/* check the header of a DNS Query packet, return 1 if it is one
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* type of query we can cache, or 0 otherwise
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*/
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static int _dnsPacket_checkQuery(DnsPacket* packet) {
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const uint8_t* p = packet->base;
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int qdCount, anCount, dnCount, arCount;
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if (p + DNS_HEADER_SIZE > packet->end) {
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LOG(INFO) << __func__ << ": query packet too small";
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return 0;
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}
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/* QR must be set to 0, opcode must be 0 and AA must be 0 */
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/* RA, Z, and RCODE must be 0 */
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if ((p[2] & 0xFC) != 0 || (p[3] & 0xCF) != 0) {
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LOG(INFO) << __func__ << ": query packet flags unsupported";
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return 0;
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}
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/* Note that we ignore the TC, RD, CD, and AD bits here for the
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* following reasons:
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*
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* - there is no point for a query packet sent to a server
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* to have the TC bit set, but the implementation might
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* set the bit in the query buffer for its own needs
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* between a resolv_cache_lookup and a resolv_cache_add.
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* We should not freak out if this is the case.
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*
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* - we consider that the result from a query might depend on
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* the RD, AD, and CD bits, so these bits
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* should be used to differentiate cached result.
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*
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* this implies that these bits are checked when hashing or
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* comparing query packets, but not TC
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*/
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/* ANCOUNT, DNCOUNT and ARCOUNT must be 0 */
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qdCount = (p[4] << 8) | p[5];
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anCount = (p[6] << 8) | p[7];
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dnCount = (p[8] << 8) | p[9];
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arCount = (p[10] << 8) | p[11];
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if (anCount != 0 || dnCount != 0 || arCount > 1) {
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LOG(INFO) << __func__ << ": query packet contains non-query records";
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return 0;
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}
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if (qdCount == 0) {
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LOG(INFO) << __func__ << ": query packet doesn't contain query record";
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return 0;
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}
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/* Check QDCOUNT QRs */
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packet->cursor = p + DNS_HEADER_SIZE;
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for (; qdCount > 0; qdCount--)
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if (!_dnsPacket_checkQR(packet)) return 0;
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return 1;
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}
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/** QUERY HASHING SUPPORT
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**
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** THE FOLLOWING CODE ASSUMES THAT THE INPUT PACKET HAS ALREADY
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** BEEN SUCCESFULLY CHECKED.
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**/
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|
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/* use 32-bit FNV hash function */
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#define FNV_MULT 16777619U
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#define FNV_BASIS 2166136261U
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static unsigned _dnsPacket_hashBytes(DnsPacket* packet, int numBytes, unsigned hash) {
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const uint8_t* p = packet->cursor;
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const uint8_t* end = packet->end;
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while (numBytes > 0 && p < end) {
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hash = hash * FNV_MULT ^ *p++;
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numBytes--;
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}
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packet->cursor = p;
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return hash;
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}
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static unsigned _dnsPacket_hashQName(DnsPacket* packet, unsigned hash) {
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const uint8_t* p = packet->cursor;
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const uint8_t* end = packet->end;
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for (;;) {
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if (p >= end) { /* should not happen */
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LOG(INFO) << __func__ << ": INTERNAL_ERROR: read-overflow";
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break;
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}
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|
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int c = *p++;
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|
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if (c == 0) break;
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if (c >= 64) {
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LOG(INFO) << __func__ << ": INTERNAL_ERROR: malformed domain";
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break;
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}
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if (p + c >= end) {
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LOG(INFO) << __func__ << ": INTERNAL_ERROR: simple label read-overflow";
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break;
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}
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while (c > 0) {
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uint8_t ch = *p++;
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ch = res_tolower(ch);
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hash = hash * FNV_MULT ^ ch;
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c--;
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}
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}
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|
packet->cursor = p;
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return hash;
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}
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|
|
static unsigned _dnsPacket_hashQR(DnsPacket* packet, unsigned hash) {
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|
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(const void* answer, int answerlen) {
|
|
ns_msg handle;
|
|
int ancount, n;
|
|
uint32_t result, ttl;
|
|
ns_rr rr;
|
|
|
|
result = 0;
|
|
if (ns_initparse((const uint8_t*) answer, answerlen, &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, const void* query, int querylen) {
|
|
DnsPacket pack[1];
|
|
|
|
memset(e, 0, sizeof(*e));
|
|
|
|
e->query = (const uint8_t*) query;
|
|
e->querylen = querylen;
|
|
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, const void* answer, int answerlen) {
|
|
Entry* e;
|
|
int size;
|
|
|
|
size = sizeof(*e) + init->querylen + answerlen;
|
|
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 = answerlen;
|
|
|
|
memcpy((char*) e->answer, answer, 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";
|
|
|
|
std::unordered_map<int, uint32_t> resolv_get_dns_event_subsampling_map() {
|
|
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{};
|
|
std::vector<std::string> subsampling_vector =
|
|
Split(GetServerConfigurableFlag("netd_native", "dns_event_subsample_map",
|
|
DEFAULT_SUBSAMPLING_MAP),
|
|
" ");
|
|
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();
|
|
}
|
|
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;
|
|
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, const void* query, int querylen, 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, querylen)) 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;
|
|
|
|
StringAppendF(&buf, "MRU LIST (%2d): ", cache->num_entries);
|
|
for (Entry* e = cache->mru_list.mru_next; e != &cache->mru_list; e = e->mru_next) {
|
|
StringAppendF(&buf, " %d", 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, const void* query, int querylen, void* answer,
|
|
int answersize, 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, querylen)) {
|
|
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 > answersize) {
|
|
/* NOTE: we return UNSUPPORTED if the answer buffer is too short */
|
|
LOG(INFO) << __func__ << ": ANSWER TOO LONG";
|
|
return RESOLV_CACHE_UNSUPPORTED;
|
|
}
|
|
|
|
memcpy(answer, 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, const void* query, int querylen, const void* answer,
|
|
int answerlen) {
|
|
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, querylen)) {
|
|
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, answerlen);
|
|
if (ttl > 0) {
|
|
e = entry_alloc(key, answer, answerlen);
|
|
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);
|
|
}
|
|
|
|
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.setServers(netconfig->nameserverSockAddrs, PROTO_TCP) ||
|
|
!netconfig->dnsStats.setServers(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) {
|
|
using android::base::StringPrintf;
|
|
std::lock_guard guard(cache_mutex);
|
|
NetConfig* netconfig = find_netconfig_locked(netid);
|
|
if (netconfig == nullptr) return {};
|
|
std::vector<std::string> result;
|
|
for (const auto& pair : netconfig->dns_event_subsampling_map) {
|
|
result.push_back(StringPrintf("%s:%d",
|
|
(pair.first == DNSEVENT_SUBSAMPLING_MAP_DEFAULT_KEY)
|
|
? "default"
|
|
: std::to_string(pair.first).c_str(),
|
|
pair.second));
|
|
}
|
|
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) {
|
|
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 = netconfig->dns_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, const std::vector<char>& query,
|
|
time_t* expiration) {
|
|
Entry key;
|
|
*expiration = -1;
|
|
|
|
// A malformed query is not allowed.
|
|
if (!entry_init_key(&key, query.data(), query.size())) {
|
|
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;
|
|
}
|
|
|
|
int resolv_stats_set_servers_for_dot(unsigned netid, const std::vector<std::string>& servers) {
|
|
std::lock_guard guard(cache_mutex);
|
|
const auto info = find_netconfig_locked(netid);
|
|
|
|
if (info == nullptr) return -ENONET;
|
|
|
|
std::vector<IPSockAddr> serverSockAddrs;
|
|
serverSockAddrs.reserve(servers.size());
|
|
for (const auto& server : servers) {
|
|
serverSockAddrs.push_back(IPSockAddr::toIPSockAddr(server, 853));
|
|
}
|
|
|
|
if (!info->dnsStats.setServers(serverSockAddrs, android::net::PROTO_DOT)) {
|
|
LOG(WARNING) << __func__ << ": netid = " << netid << ", failed to set dns 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));
|
|
}
|
|
}
|