res_cache.c revision dd16182b4b3f107d5c26015622c1cb8c06619ad7
11dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 21dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Copyright (C) 2008 The Android Open Source Project 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * All rights reserved. 41dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 51dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Redistribution and use in source and binary forms, with or without 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * modification, are permitted provided that the following conditions 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * are met: 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * * Redistributions of source code must retain the above copyright 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer. 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * * Redistributions in binary form must reproduce the above copyright 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * notice, this list of conditions and the following disclaimer in 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the documentation and/or other materials provided with the 131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * distribution. 141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * SUCH DAMAGE. 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "resolv_cache.h" 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdlib.h> 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <string.h> 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <time.h> 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "pthread.h" 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 353e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk#include <errno.h> 363e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk#include "arpa_nameser.h" 373a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk#include <sys/system_properties.h> 383e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* This code implements a small and *simple* DNS resolver cache. 401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 413e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * It is only used to cache DNS answers for a time defined by the smallest TTL 423e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * among the answer records in order to reduce DNS traffic. It is not supposed 433e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * to be a full DNS cache, since we plan to implement that in the future in a 443e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * dedicated process running on the system. 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Note that its design is kept simple very intentionally, i.e.: 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - it takes raw DNS query packet data as input, and returns raw DNS 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * answer packet data as output 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * (this means that two similar queries that encode the DNS name 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * differently will be treated distinctly). 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 543e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * the smallest TTL value among the answer records are used as the time 553e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * to keep an answer in the cache. 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * this is bad, but we absolutely want to avoid parsing the answer packets 581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * (and should be solved by the later full DNS cache process). 591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - the implementation is just a (query-data) => (answer-data) hash table 611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * with a trivial least-recently-used expiration policy. 621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Doing this keeps the code simple and avoids to deal with a lot of things 641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * that a full DNS cache is expected to do. 651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The API is also very simple: 671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - the client calls _resolv_cache_get() to obtain a handle to the cache. 691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * this will initialize the cache on first usage. the result can be NULL 701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if the cache is disabled. 711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - the client calls _resolv_cache_lookup() before performing a query 731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if the function returns RESOLV_CACHE_FOUND, a copy of the answer data 751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * has been copied into the client-provided answer buffer. 761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if the function returns RESOLV_CACHE_NOTFOUND, the client should perform 781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * a request normally, *then* call _resolv_cache_add() to add the received 791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * answer to the cache. 801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if the function returns RESOLV_CACHE_UNSUPPORTED, the client should 821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * perform a request normally, and *not* call _resolv_cache_add() 831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * note that RESOLV_CACHE_UNSUPPORTED is also returned if the answer buffer 851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is too short to accomodate the cached result. 861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - when network settings change, the cache must be flushed since the list 881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * of DNS servers probably changed. this is done by calling 891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * _resolv_cache_reset() 901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the parameter to this function must be an ever-increasing generation 921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * number corresponding to the current network settings state. 931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * This is done because several threads could detect the same network 951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * settings change (but at different times) and will all end up calling the 961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * same function. Comparing with the last used generation number ensures 971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * that the cache is only flushed once per network change. 981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* the name of an environment variable that will be checked the first time 1011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * this code is called if its value is "0", then the resolver cache is 1021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * disabled. 1031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define CONFIG_ENV "BIONIC_DNSCACHE" 1051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* entries older than CONFIG_SECONDS seconds are always discarded. 1071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define CONFIG_SECONDS (60*10) /* 10 minutes */ 1091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1103a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk/* default number of entries kept in the cache. This value has been 1111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * determined by browsing through various sites and counting the number 1121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * of corresponding requests. Keep in mind that our framework is currently 1131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * performing two requests per name lookup (one for IPv4, the other for IPv6) 1141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.google.com 4 1161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.ysearch.com 6 1171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.amazon.com 8 1181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.nytimes.com 22 1191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.espn.com 28 1201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.msn.com 28 1211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * www.lemonde.fr 35 1221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * (determined in 2009-2-17 from Paris, France, results may vary depending 1241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * on location) 1251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * most high-level websites use lots of media/ad servers with different names 1271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * but these are generally reused when browsing through the site. 1281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1293a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * As such, a value of 64 should be relatively comfortable at the moment. 1303a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * 1313a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * The system property ro.net.dns_cache_size can be used to override the default 1323a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * value with a custom value 1331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 1341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define CONFIG_MAX_ENTRIES 64 1351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1363a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk/* name of the system property that can be used to set the cache size */ 1373a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk#define DNS_CACHE_SIZE_PROP_NAME "ro.net.dns_cache_size" 1383a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk 1391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 1401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 1411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 1421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 1431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 1441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 1451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 1461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* set to 1 to debug cache operations */ 1481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DEBUG 0 1491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* set to 1 to debug query data */ 1511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DEBUG_DATA 0 1521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1533e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk#undef XLOG 1541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG 1551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# include <logd.h> 1561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# define XLOG(...) \ 1571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __libc_android_log_print(ANDROID_LOG_DEBUG,"libc",__VA_ARGS__) 1581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdio.h> 1601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <stdarg.h> 1611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1623e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk#include <arpa/inet.h> 1633e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk#include "resolv_private.h" 1643e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 1651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/** BOUNDED BUFFER FORMATTING 1661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project **/ 1671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* technical note: 1691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the following debugging routines are used to append data to a bounded 1711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * buffer they take two parameters that are: 1721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - p : a pointer to the current cursor position in the buffer 1741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * this value is initially set to the buffer's address. 1751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - end : the address of the buffer's limit, i.e. of the first byte 1771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * after the buffer. this address should never be touched. 1781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * IMPORTANT: it is assumed that end > buffer_address, i.e. 1801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * that the buffer is at least one byte. 1811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the _bprint_() functions return the new value of 'p' after the data 1831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * has been appended, and also ensure the following: 1841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - the returned value will never be strictly greater than 'end' 1861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - a return value equal to 'end' means that truncation occured 1881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * (in which case, end[-1] will be set to 0) 1891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - after returning from a _bprint_() function, the content of the buffer 1911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is always 0-terminated, even in the event of truncation. 1921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * these conventions allow you to call _bprint_ functions multiple times and 1941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * only check for truncation at the end of the sequence, as in: 1951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * char buff[1000], *p = buff, *end = p + sizeof(buff); 1971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 1981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * p = _bprint_c(p, end, '"'); 1991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * p = _bprint_s(p, end, my_string); 2001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * p = _bprint_c(p, end, '"'); 2011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 2021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * if (p >= end) { 2031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * // buffer was too small 2041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * } 2051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 2061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * printf( "%s", buff ); 2071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 2081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add a char to a bounded buffer */ 2101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint_c( char* p, char* end, int c ) 2121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p < end) { 2141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p+1 == end) 2151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *p++ = 0; 2161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else { 2171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *p++ = (char) c; 2181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *p = 0; 2191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 2201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 2211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 2221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 2231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add a sequence of bytes to a bounded buffer */ 2251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint_b( char* p, char* end, const char* buf, int len ) 2271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int avail = end - p; 2291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (avail <= 0 || len <= 0) 2311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 2321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (avail > len) 2341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project avail = len; 2351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project memcpy( p, buf, avail ); 2371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p += avail; 2381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p < end) 2401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p[0] = 0; 2411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else 2421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project end[-1] = 0; 2431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 2451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 2461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add a string to a bounded buffer */ 2481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint_s( char* p, char* end, const char* str ) 2501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _bprint_b(p, end, str, strlen(str)); 2521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 2531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add a formatted string to a bounded buffer */ 2551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint( char* p, char* end, const char* format, ... ) 2571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int avail, n; 2591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project va_list args; 2601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project avail = end - p; 2621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (avail <= 0) 2641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 2651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project va_start(args, format); 267d378c68d74cb4fdac450650fe816c9d649c8edafDavid 'Digit' Turner n = vsnprintf( p, avail, format, args); 2681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project va_end(args); 2691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* certain C libraries return -1 in case of truncation */ 2711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (n < 0 || n > avail) 2721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project n = avail; 2731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p += n; 2751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* certain C libraries do not zero-terminate in case of truncation */ 2761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p == end) 2771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p[-1] = 0; 2781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 2801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 2811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add a hex value to a bounded buffer, up to 8 digits */ 2831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint_hex( char* p, char* end, unsigned value, int numDigits ) 2851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project char text[sizeof(unsigned)*2]; 2871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int nn = 0; 2881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (numDigits-- > 0) { 2901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project text[nn++] = "0123456789abcdef"[(value >> (numDigits*4)) & 15]; 2911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 2921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _bprint_b(p, end, text, nn); 2931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 2941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 2951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* add the hexadecimal dump of some memory area to a bounded buffer */ 2961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 2971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_bprint_hexdump( char* p, char* end, const uint8_t* data, int datalen ) 2981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 2991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int lineSize = 16; 3001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (datalen > 0) { 3021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int avail = datalen; 3031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int nn; 3041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (avail > lineSize) 3061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project avail = lineSize; 3071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (nn = 0; nn < avail; nn++) { 3091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (nn > 0) 3101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_c(p, end, ' '); 3111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_hex(p, end, data[nn], 2); 3121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 3131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for ( ; nn < lineSize; nn++ ) { 3141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_s(p, end, " "); 3151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 3161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_s(p, end, " "); 3171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (nn = 0; nn < avail; nn++) { 3191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int c = data[nn]; 3201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c < 32 || c > 127) 3221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c = '.'; 3231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_c(p, end, c); 3251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 3261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_c(p, end, '\n'); 3271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project data += avail; 3291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project datalen -= avail; 3301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 3311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 3321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 3331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* dump the content of a query of packet to the log */ 3351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 3361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source ProjectXLOG_BYTES( const void* base, int len ) 3371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 3381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project char buff[1024]; 3391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project char* p = buff, *end = p + sizeof(buff); 3401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_hexdump(p, end, base, len); 3421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s",buff); 3431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 3441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#else /* !DEBUG */ 3461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# define XLOG(...) ((void)0) 3471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# define XLOG_BYTES(a,b) ((void)0) 3481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 3491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic time_t 3511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_time_now( void ) 3521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 3531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project struct timeval tv; 3541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project gettimeofday( &tv, NULL ); 3561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return tv.tv_sec; 3571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 3581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 3591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* reminder: the general format of a DNS packet is the following: 3601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * HEADER (12 bytes) 3621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * QUESTION (variable) 3631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ANSWER (variable) 3641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * AUTHORITY (variable) 3651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ADDITIONNAL (variable) 3661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the HEADER is made of: 3681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ID : 16 : 16-bit unique query identification field 3701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * QR : 1 : set to 0 for queries, and 1 for responses 3721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Opcode : 4 : set to 0 for queries 3731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * AA : 1 : set to 0 for queries 3741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * TC : 1 : truncation flag, will be set to 0 in queries 3751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * RD : 1 : recursion desired 3761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * RA : 1 : recursion available (0 in queries) 3781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Z : 3 : three reserved zero bits 3791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * RCODE : 4 : response code (always 0=NOERROR in queries) 3801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * QDCount: 16 : question count 3821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ANCount: 16 : Answer count (0 in queries) 3831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * NSCount: 16: Authority Record count (0 in queries) 3841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ARCount: 16: Additionnal Record count (0 in queries) 3851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the QUESTION is made of QDCount Question Record (QRs) 3871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the ANSWER is made of ANCount RRs 3881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the AUTHORITY is made of NSCount RRs 3891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the ADDITIONNAL is made of ARCount RRs 3901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Each Question Record (QR) is made of: 3921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * QNAME : variable : Query DNS NAME 3941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255) 3951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * CLASS : 16 : class of query (IN=1) 3961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Each Resource Record (RR) is made of: 3981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 3991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * NAME : variable : DNS NAME 4001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * TYPE : 16 : type of query (A=1, PTR=12, MX=15, AAAA=28, ALL=255) 4011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * CLASS : 16 : class of query (IN=1) 4021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * TTL : 32 : seconds to cache this RR (0=none) 4031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * RDLENGTH: 16 : size of RDDATA in bytes 4041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * RDDATA : variable : RR data (depends on TYPE) 4051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Each QNAME contains a domain name encoded as a sequence of 'labels' 4071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * terminated by a zero. Each label has the following format: 4081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * LEN : 8 : lenght of label (MUST be < 64) 4101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * NAME : 8*LEN : label length (must exclude dots) 4111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * A value of 0 in the encoding is interpreted as the 'root' domain and 4131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * terminates the encoding. So 'www.android.com' will be encoded as: 4141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * <3>www<7>android<3>com<0> 4161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Where <n> represents the byte with value 'n' 4181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Each NAME reflects the QNAME of the question, but has a slightly more 4201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * complex encoding in order to provide message compression. This is achieved 4211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * by using a 2-byte pointer, with format: 4221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * TYPE : 2 : 0b11 to indicate a pointer, 0b01 and 0b10 are reserved 4241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * OFFSET : 14 : offset to another part of the DNS packet 4251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The offset is relative to the start of the DNS packet and must point 4271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * A pointer terminates the encoding. 4281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The NAME can be encoded in one of the following formats: 4301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - a sequence of simple labels terminated by 0 (like QNAMEs) 4321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - a single pointer 4331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - a sequence of simple labels terminated by a pointer 4341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * A pointer shall always point to either a pointer of a sequence of 4361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * labels (which can themselves be terminated by either a 0 or a pointer) 4371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The expanded length of a given domain name should not exceed 255 bytes. 4391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 4401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * NOTE: we don't parse the answer packets, so don't need to deal with NAME 4411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * records, only QNAMEs. 4421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 4431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_HEADER_SIZE 12 4451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_TYPE_A "\00\01" /* big-endian decimal 1 */ 4471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_TYPE_PTR "\00\014" /* big-endian decimal 12 */ 4481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_TYPE_MX "\00\017" /* big-endian decimal 15 */ 4491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_TYPE_AAAA "\00\034" /* big-endian decimal 28 */ 4501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_TYPE_ALL "\00\0377" /* big-endian decimal 255 */ 4511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define DNS_CLASS_IN "\00\01" /* big-endian decimal 1 */ 4531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projecttypedef struct { 4551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* base; 4561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end; 4571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* cursor; 4581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} DnsPacket; 4591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 4611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_init( DnsPacket* packet, const uint8_t* buff, int bufflen ) 4621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 4631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->base = buff; 4641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->end = buff + bufflen; 4651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = buff; 4661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 4671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 4691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_rewind( DnsPacket* packet ) 4701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 4711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = packet->base; 4721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 4731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 4751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_skip( DnsPacket* packet, int count ) 4761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 4771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor + count; 4781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p > packet->end) 4801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = packet->end; 4811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p; 4831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 4841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 4861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_readInt16( DnsPacket* packet ) 4871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 4881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 4891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p+2 > packet->end) 4911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return -1; 4921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p+2; 4941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (p[0]<< 8) | p[1]; 4951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 4961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 4971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/** QUERY CHECKING 4981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project **/ 4991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* check bytes in a dns packet. returns 1 on success, 0 on failure. 5011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the cursor is only advanced in the case of success 5021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 5031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 5041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_checkBytes( DnsPacket* packet, int numBytes, const void* bytes ) 5051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 5061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 5071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p + numBytes > packet->end) 5091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (memcmp(p, bytes, numBytes) != 0) 5121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p + numBytes; 5151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 5161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 5171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* parse and skip a given QNAME stored in a query packet, 5191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * from the current cursor position. returns 1 on success, 5201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * or 0 for malformed data. 5211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 5221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 5231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_checkQName( DnsPacket* packet ) 5241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 5251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 5261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end = packet->end; 5271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (;;) { 5291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int c; 5301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p >= end) 5321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 5331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c = *p++; 5351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c == 0) { 5371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p; 5381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 5391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 5401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we don't expect label compression in QNAMEs */ 5421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c >= 64) 5431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 5441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p += c; 5461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we rely on the bound check at the start 5471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * of the loop here */ 5481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 5491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* malformed data */ 5501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("malformed QNAME"); 5511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 5531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* parse and skip a given QR stored in a packet. 5551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * returns 1 on success, and 0 on failure 5561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 5571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 5581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_checkQR( DnsPacket* packet ) 5591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 5601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int len; 5611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!_dnsPacket_checkQName(packet)) 5631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* TYPE must be one of the things we support */ 5661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!_dnsPacket_checkBytes(packet, 2, DNS_TYPE_A) && 5671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_PTR) && 5681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_MX) && 5691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_AAAA) && 5701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project !_dnsPacket_checkBytes(packet, 2, DNS_TYPE_ALL)) 5711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project { 5721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("unsupported TYPE"); 5731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 5751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* CLASS must be IN */ 5761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!_dnsPacket_checkBytes(packet, 2, DNS_CLASS_IN)) { 5771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("unsupported CLASS"); 5781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 5801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 5821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 5831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* check the header of a DNS Query packet, return 1 if it is one 5851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * type of query we can cache, or 0 otherwise 5861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 5871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 5881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_checkQuery( DnsPacket* packet ) 5891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 5901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->base; 5911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int qdCount, anCount, dnCount, arCount; 5921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p + DNS_HEADER_SIZE > packet->end) { 5941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("query packet too small"); 5951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 5961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 5971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 5981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* QR must be set to 0, opcode must be 0 and AA must be 0 */ 5991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* RA, Z, and RCODE must be 0 */ 6001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ((p[2] & 0xFC) != 0 || p[3] != 0) { 6011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("query packet flags unsupported"); 6021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 6031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 6041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* Note that we ignore the TC and RD bits here for the 6061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * following reasons: 6071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 6081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - there is no point for a query packet sent to a server 6091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * to have the TC bit set, but the implementation might 6101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * set the bit in the query buffer for its own needs 6111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * between a _resolv_cache_lookup and a 6121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * _resolv_cache_add. We should not freak out if this 6131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is the case. 6141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 6151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * - we consider that the result from a RD=0 or a RD=1 6161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * query might be different, hence that the RD bit 6171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * should be used to differentiate cached result. 6181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 6191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * this implies that RD is checked when hashing or 6201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * comparing query packets, but not TC 6211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 6221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* ANCOUNT, DNCOUNT and ARCOUNT must be 0 */ 6241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project qdCount = (p[4] << 8) | p[5]; 6251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project anCount = (p[6] << 8) | p[7]; 6261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project dnCount = (p[8] << 8) | p[9]; 6271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project arCount = (p[10]<< 8) | p[11]; 6281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (anCount != 0 || dnCount != 0 || arCount != 0) { 6301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("query packet contains non-query records"); 6311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 6321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 6331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (qdCount == 0) { 6351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("query packet doesn't contain query record"); 6361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 6371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 6381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* Check QDCOUNT QRs */ 6401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p + DNS_HEADER_SIZE; 6411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (;qdCount > 0; qdCount--) 6431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!_dnsPacket_checkQR(packet)) 6441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 6451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 6471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 6481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/** QUERY DEBUGGING 6501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project **/ 6511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG 6521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 6531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_bprintQName(DnsPacket* packet, char* bp, char* bend) 6541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 6551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 6561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end = packet->end; 6571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int first = 1; 6581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (;;) { 6601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int c; 6611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p >= end) 6631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 6641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c = *p++; 6661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c == 0) { 6681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p; 6691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return bp; 6701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 6711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we don't expect label compression in QNAMEs */ 6731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c >= 64) 6741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 6751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (first) 6771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project first = 0; 6781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else 6791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project bp = _bprint_c(bp, bend, '.'); 6801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project bp = _bprint_b(bp, bend, (const char*)p, c); 6821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p += c; 6841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we rely on the bound check at the start 6851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * of the loop here */ 6861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 6871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* malformed data */ 6881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project bp = _bprint_s(bp, bend, "<MALFORMED>"); 6891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return bp; 6901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 6911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 6921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 6931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_bprintQR(DnsPacket* packet, char* p, char* end) 6941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 6951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define QQ(x) { DNS_TYPE_##x, #x } 6961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project static const struct { 6971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const char* typeBytes; 6981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const char* typeString; 6991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } qTypes[] = 7001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project { 7011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project QQ(A), QQ(PTR), QQ(MX), QQ(AAAA), QQ(ALL), 7021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project { NULL, NULL } 7031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project }; 7041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int nn; 7051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const char* typeString = NULL; 7061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* dump QNAME */ 7081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _dnsPacket_bprintQName(packet, p, end); 7091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* dump TYPE */ 7111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_s(p, end, " ("); 7121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (nn = 0; qTypes[nn].typeBytes != NULL; nn++) { 7141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (_dnsPacket_checkBytes(packet, 2, qTypes[nn].typeBytes)) { 7151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project typeString = qTypes[nn].typeString; 7161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 7171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (typeString != NULL) 7211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_s(p, end, typeString); 7221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else { 7231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int typeCode = _dnsPacket_readInt16(packet); 7241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint(p, end, "UNKNOWN-%d", typeCode); 7251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_c(p, end, ')'); 7281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* skip CLASS */ 7301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(packet, 2); 7311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 7321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 7331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* this function assumes the packet has already been checked */ 7351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char* 7361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_bprintQuery( DnsPacket* packet, char* p, char* end ) 7371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 7381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int qdCount; 7391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (packet->base[2] & 0x1) { 7411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint_s(p, end, "RECURSIVE "); 7421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(packet, 4); 7451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project qdCount = _dnsPacket_readInt16(packet); 7461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(packet, 6); 7471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for ( ; qdCount > 0; qdCount-- ) { 7491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _dnsPacket_bprintQR(packet, p, end); 7501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return p; 7521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 7531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 7541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/** QUERY HASHING SUPPORT 7571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** 7581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** THE FOLLOWING CODE ASSUMES THAT THE INPUT PACKET HAS ALREADY 7591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** BEEN SUCCESFULLY CHECKED. 7601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project **/ 7611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* use 32-bit FNV hash function */ 7631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define FNV_MULT 16777619U 7641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define FNV_BASIS 2166136261U 7651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic unsigned 7671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_hashBytes( DnsPacket* packet, int numBytes, unsigned hash ) 7681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 7691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 7701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end = packet->end; 7711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (numBytes > 0 && p < end) { 7731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = hash*FNV_MULT ^ *p++; 7741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p; 7761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return hash; 7771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 7781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic unsigned 7811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_hashQName( DnsPacket* packet, unsigned hash ) 7821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 7831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p = packet->cursor; 7841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end = packet->end; 7851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (;;) { 7871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int c; 7881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p >= end) { /* should not happen */ 7901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: read-overflow !!\n", __FUNCTION__); 7911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 7921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 7931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c = *p++; 7951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c == 0) 7971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 7981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 7991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c >= 64) { 8001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: malformed domain !!\n", __FUNCTION__); 8011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p + c >= end) { 8041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: simple label read-overflow !!\n", 8051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __FUNCTION__); 8061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (c > 0) { 8091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = hash*FNV_MULT ^ *p++; 8101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c -= 1; 8111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project packet->cursor = p; 8141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return hash; 8151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 8161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic unsigned 8181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_hashQR( DnsPacket* packet, unsigned hash ) 8191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 8201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int len; 8211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = _dnsPacket_hashQName(packet, hash); 8231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = _dnsPacket_hashBytes(packet, 4, hash); /* TYPE and CLASS */ 8241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return hash; 8251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 8261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic unsigned 8281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_hashQuery( DnsPacket* packet ) 8291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 8301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project unsigned hash = FNV_BASIS; 8311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int count; 8321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_rewind(packet); 8331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we ignore the TC bit for reasons explained in 8351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * _dnsPacket_checkQuery(). 8361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 8371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * however we hash the RD bit to differentiate 8381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * between answers for recursive and non-recursive 8391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * queries. 8401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 8411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = hash*FNV_MULT ^ (packet->base[2] & 1); 8421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* assume: other flags are 0 */ 8441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(packet, 4); 8451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* read QDCOUNT */ 8471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project count = _dnsPacket_readInt16(packet); 8481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* assume: ANcount, NScount, ARcount are 0 */ 8501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(packet, 6); 8511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* hash QDCOUNT QRs */ 8531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for ( ; count > 0; count-- ) 8541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hash = _dnsPacket_hashQR(packet, hash); 8551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return hash; 8571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 8581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/** QUERY COMPARISON 8611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** 8621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** THE FOLLOWING CODE ASSUMES THAT THE INPUT PACKETS HAVE ALREADY 8631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ** BEEN SUCCESFULLY CHECKED. 8641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project **/ 8651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 8671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_isEqualDomainName( DnsPacket* pack1, DnsPacket* pack2 ) 8681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 8691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p1 = pack1->cursor; 8701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end1 = pack1->end; 8711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p2 = pack2->cursor; 8721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* end2 = pack2->end; 8731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (;;) { 8751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int c1, c2; 8761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (p1 >= end1 || p2 >= end2) { 8781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: read-overflow !!\n", __FUNCTION__); 8791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c1 = *p1++; 8821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project c2 = *p2++; 8831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c1 != c2) 8841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 8861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c1 == 0) { 8871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pack1->cursor = p1; 8881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pack2->cursor = p2; 8891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 8901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (c1 >= 64) { 8921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: malformed domain !!\n", __FUNCTION__); 8931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 8951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ((p1+c1 > end1) || (p2+c1 > end2)) { 8961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: INTERNAL_ERROR: simple label read-overflow !!\n", 8971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __FUNCTION__); 8981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 8991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (memcmp(p1, p2, c1) != 0) 9011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 9021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p1 += c1; 9031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p2 += c1; 9041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we rely on the bound checks at the start of the loop */ 9051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* not the same, or one is malformed */ 9071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("different DN"); 9081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 9101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 9121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_isEqualBytes( DnsPacket* pack1, DnsPacket* pack2, int numBytes ) 9131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 9141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p1 = pack1->cursor; 9151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* p2 = pack2->cursor; 9161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ( p1 + numBytes > pack1->end || p2 + numBytes > pack2->end ) 9181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ( memcmp(p1, p2, numBytes) != 0 ) 9211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pack1->cursor += numBytes; 9241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pack2->cursor += numBytes; 9251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 9261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 9271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 9291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_isEqualQR( DnsPacket* pack1, DnsPacket* pack2 ) 9301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 9311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compare domain name encoding + TYPE + CLASS */ 9321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ( !_dnsPacket_isEqualDomainName(pack1, pack2) || 9331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project !_dnsPacket_isEqualBytes(pack1, pack2, 2+2) ) 9341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 9371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 9381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 9401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dnsPacket_isEqualQuery( DnsPacket* pack1, DnsPacket* pack2 ) 9411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 9421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int count1, count2; 9431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compare the headers, ignore most fields */ 9451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_rewind(pack1); 9461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_rewind(pack2); 9471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compare RD, ignore TC, see comment in _dnsPacket_checkQuery */ 9491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if ((pack1->base[2] & 1) != (pack2->base[2] & 1)) { 9501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("different RD"); 9511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* assume: other flags are all 0 */ 9551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(pack1, 4); 9561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(pack2, 4); 9571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compare QDCOUNT */ 9591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project count1 = _dnsPacket_readInt16(pack1); 9601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project count2 = _dnsPacket_readInt16(pack2); 9611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (count1 != count2 || count1 < 0) { 9621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("different QDCOUNT"); 9631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* assume: ANcount, NScount and ARcount are all 0 */ 9671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(pack1, 6); 9681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_skip(pack2, 6); 9691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compare the QDCOUNT QRs */ 9711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for ( ; count1 > 0; count1-- ) { 9721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!_dnsPacket_isEqualQR(pack1, pack2)) { 9731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("different QR"); 9741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 9751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 9771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 1; 9781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 9791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 9811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 9821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 9831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 9841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 9851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 9861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 9871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* cache entry. for simplicity, 'hash' and 'hlink' are inlined in this 9891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * structure though they are conceptually part of the hash table. 9901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 9911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * similarly, mru_next and mru_prev are part of the global MRU list 9921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 9931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projecttypedef struct Entry { 9941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project unsigned int hash; /* hash value */ 9951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project struct Entry* hlink; /* next in collision chain */ 9961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project struct Entry* mru_prev; 9971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project struct Entry* mru_next; 9981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 9991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* query; 10001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int querylen; 10011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const uint8_t* answer; 10021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int answerlen; 10033e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk time_t expires; /* time_t when the entry isn't valid any more */ 10043e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk int id; /* for debugging purpose */ 10051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} Entry; 10061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10073e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk/** 10083e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * Parse the answer records and find the smallest 10093e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * TTL among the answer records. 10103e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * 10113e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * The returned TTL is the number of seconds to 10123e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * keep the answer in the cache. 10133e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * 10143e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * In case of parse error zero (0) is returned which 10153e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk * indicates that the answer shall not be cached. 10163e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk */ 10173e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falkstatic u_long 10183e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falkanswer_getTTL(const void* answer, int answerlen) 10193e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk{ 10203e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk ns_msg handle; 10213e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk int ancount, n; 10223e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk u_long result, ttl; 10233e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk ns_rr rr; 10243e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 10253e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk result = 0; 10263e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (ns_initparse(answer, answerlen, &handle) >= 0) { 10273e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk // get number of answer records 10283e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk ancount = ns_msg_count(handle, ns_s_an); 10293e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk for (n = 0; n < ancount; n++) { 10303e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (ns_parserr(&handle, ns_s_an, n, &rr) == 0) { 10313e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk ttl = ns_rr_ttl(rr); 10323e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (n == 0 || ttl < result) { 10333e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk result = ttl; 10343e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 10353e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } else { 10363e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG("ns_parserr failed ancount no = %d. errno = %s\n", n, strerror(errno)); 10373e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 10383e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 10393e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } else { 10403e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG("ns_parserr failed. %s\n", strerror(errno)); 10413e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 10423e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 10433e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG("TTL = %d\n", result); 10443e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 10453e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk return result; 10463e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk} 10471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 10491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_free( Entry* e ) 10501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 10511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* everything is allocated in a single memory block */ 10521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e) { 10531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project free(e); 10541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 10551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 10561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic __inline__ void 10581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_mru_remove( Entry* e ) 10591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 10601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->mru_prev->mru_next = e->mru_next; 10611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->mru_next->mru_prev = e->mru_prev; 10621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 10631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic __inline__ void 10651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_mru_add( Entry* e, Entry* list ) 10661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 10671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* first = list->mru_next; 10681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->mru_next = first; 10701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->mru_prev = list; 10711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project list->mru_next = e; 10731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project first->mru_prev = e; 10741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 10751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* compute the hash of a given entry, this is a hash of most 10771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * data in the query (key) */ 10781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic unsigned 10791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_hash( const Entry* e ) 10801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 10811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project DnsPacket pack[1]; 10821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_init(pack, e->query, e->querylen); 10841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _dnsPacket_hashQuery(pack); 10851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 10861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* initialize an Entry as a search key, this also checks the input query packet 10881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * returns 1 on success, or 0 in case of unsupported/malformed data */ 10891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 10901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_init_key( Entry* e, const void* query, int querylen ) 10911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 10921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project DnsPacket pack[1]; 10931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project memset(e, 0, sizeof(*e)); 10951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 10961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->query = query; 10971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->querylen = querylen; 10981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->hash = entry_hash(e); 10991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_init(pack, query, querylen); 11011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _dnsPacket_checkQuery(pack); 11031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 11041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* allocate a new entry as a cache node */ 11061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic Entry* 11071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_alloc( const Entry* init, const void* answer, int answerlen ) 11081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 11091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e; 11101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int size; 11111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project size = sizeof(*e) + init->querylen + answerlen; 11131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e = calloc(size, 1); 11141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e == NULL) 11151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return e; 11161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->hash = init->hash; 11181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->query = (const uint8_t*)(e+1); 11191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->querylen = init->querylen; 11201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project memcpy( (char*)e->query, init->query, e->querylen ); 11221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->answer = e->query + e->querylen; 11241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->answerlen = answerlen; 11251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project memcpy( (char*)e->answer, answer, e->answerlen ); 11271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return e; 11291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 11301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic int 11321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectentry_equals( const Entry* e1, const Entry* e2 ) 11331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 11341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project DnsPacket pack1[1], pack2[1]; 11351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e1->querylen != e2->querylen) { 11371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return 0; 11381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 11391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_init(pack1, e1->query, e1->querylen); 11401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_init(pack2, e2->query, e2->querylen); 11411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _dnsPacket_isEqualQuery(pack1, pack2); 11431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 11441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 11461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 11471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 11481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 11491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 11501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 11511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 11521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* We use a simple hash table with external collision lists 11541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * for simplicity, the hash-table fields 'hash' and 'hlink' are 11551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * inlined in the Entry structure. 11561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 11571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projecttypedef struct resolv_cache { 11593a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk int max_entries; 11601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int num_entries; 11611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry mru_list; 11621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_t lock; 11631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project unsigned generation; 11641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int last_id; 11653a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk Entry* entries; 11661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} Cache; 11671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#define HTABLE_VALID(x) ((x) != NULL && (x) != HTABLE_DELETED) 11701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 11721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_flush_locked( Cache* cache ) 11731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 11741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int nn; 11751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project time_t now = _time_now(); 11761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11773a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk for (nn = 0; nn < cache->max_entries; nn++) 11781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project { 11793a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk Entry** pnode = (Entry**) &cache->entries[nn]; 11801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (*pnode != NULL) { 11821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* node = *pnode; 11831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *pnode = node->hlink; 11841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_free(node); 11851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 11861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 11871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache->mru_list.mru_next = cache->mru_list.mru_prev = &cache->mru_list; 11891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache->num_entries = 0; 11901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache->last_id = 0; 11911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("*************************\n" 11931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project "*** DNS CACHE FLUSHED ***\n" 11941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project "*************************"); 11951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 11961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 11973a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk/* Return max number of entries allowed in the cache, 11983a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * i.e. cache size. The cache size is either defined 11993a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * by system property ro.net.dns_cache_size or by 12003a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * CONFIG_MAX_ENTRIES if system property not set 12013a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk * or set to invalid value. */ 12023a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falkstatic int 12033a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk_res_cache_get_max_entries( void ) 12043a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk{ 12053a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk int result = -1; 12063a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk char cache_size[PROP_VALUE_MAX]; 12073a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk 12083a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk if (__system_property_get(DNS_CACHE_SIZE_PROP_NAME, cache_size) > 0) { 12093a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk result = atoi(cache_size); 12103a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk } 12113a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk 12123a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk // ro.net.dns_cache_size not set or set to negative value 12133a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk if (result <= 0) { 12143a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk result = CONFIG_MAX_ENTRIES; 12153a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk } 12163a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk 12173a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk XLOG("cache size: %d", result); 12183a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk return result; 12193a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk} 12203a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk 12217cc5666d94615d9249163dc7ac0f58c2614497ceJim Huangstatic struct resolv_cache* 12221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_resolv_cache_create( void ) 12231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 12241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project struct resolv_cache* cache; 12251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache = calloc(sizeof(*cache), 1); 12271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (cache) { 12283a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk cache->max_entries = _res_cache_get_max_entries(); 12293a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk cache->entries = calloc(sizeof(*cache->entries), cache->max_entries); 12303a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk if (cache->entries) { 12313a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk cache->generation = ~0U; 12323a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk pthread_mutex_init( &cache->lock, NULL ); 12333a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk cache->mru_list.mru_prev = cache->mru_list.mru_next = &cache->mru_list; 12343a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk XLOG("%s: cache created\n", __FUNCTION__); 12353a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk } else { 12363a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk free(cache); 12373a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk cache = NULL; 12383a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk } 12391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 12401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return cache; 12411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 12421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG 12451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 12461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_dump_query( const uint8_t* query, int querylen ) 12471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 12481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project char temp[256], *p=temp, *end=p+sizeof(temp); 12491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project DnsPacket pack[1]; 12501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _dnsPacket_init(pack, query, querylen); 12521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _dnsPacket_bprintQuery(pack, p, end); 12531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("QUERY: %s", temp); 12541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 12551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 12571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_dump_mru( Cache* cache ) 12581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 12591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project char temp[512], *p=temp, *end=p+sizeof(temp); 12601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e; 12611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint(temp, end, "MRU LIST (%2d): ", cache->num_entries); 12631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project for (e = cache->mru_list.mru_next; e != &cache->mru_list; e = e->mru_next) 12641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project p = _bprint(p, end, " %d", e->id); 12651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 12661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s", temp); 12671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 12683e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 12693e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falkstatic void 12703e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk_dump_answer(const void* answer, int answerlen) 12713e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk{ 12723e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk res_state statep; 12733e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk FILE* fp; 12743e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk char* buf; 12753e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk int fileLen; 12763e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 12773e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fp = fopen("/data/reslog.txt", "w+"); 12783e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (fp != NULL) { 12793e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk statep = __res_get_state(); 12803e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 12813e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk res_pquery(statep, answer, answerlen, fp); 12823e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk 12833e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk //Get file length 12843e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fseek(fp, 0, SEEK_END); 12853e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fileLen=ftell(fp); 12863e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fseek(fp, 0, SEEK_SET); 12873e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk buf = (char *)malloc(fileLen+1); 12883e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (buf != NULL) { 12893e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk //Read file contents into buffer 12903e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fread(buf, fileLen, 1, fp); 12913e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG("%s\n", buf); 12923e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk free(buf); 12933e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 12943e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk fclose(fp); 12953e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk remove("/data/reslog.txt"); 12963e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 12973e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk else { 12983e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG("_dump_answer: can't open file\n"); 12993e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 13003e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk} 13011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 13021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG 13041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# define XLOG_QUERY(q,len) _dump_query((q), (len)) 13053e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk# define XLOG_ANSWER(a, len) _dump_answer((a), (len)) 13061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#else 13071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project# define XLOG_QUERY(q,len) ((void)0) 13083e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk# define XLOG_ANSWER(a,len) ((void)0) 13091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 13101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* This function tries to find a key within the hash table 13121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * In case of success, it will return a *pointer* to the hashed key. 13131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * In case of failure, it will return a *pointer* to NULL 13141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 13151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * So, the caller must check '*result' to check for success/failure. 13161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 13171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The main idea is that the result can later be used directly in 13181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * calls to _resolv_cache_add or _resolv_cache_remove as the 'lookup' 13191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * parameter. This makes the code simpler and avoids re-searching 13201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * for the key position in the htable. 13211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 13221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * The result of a lookup_p is only valid until you alter the hash 13231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * table. 13241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 13251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic Entry** 13261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_lookup_p( Cache* cache, 13271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* key ) 13281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 13293a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk int index = key->hash % cache->max_entries; 13303a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk Entry** pnode = (Entry**) &cache->entries[ index ]; 13311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project while (*pnode != NULL) { 13331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* node = *pnode; 13341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (node == NULL) 13361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 13371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (node->hash == key->hash && entry_equals(node, key)) 13391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project break; 13401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pnode = &node->hlink; 13421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 13431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return pnode; 13441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 13451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* Add a new entry to the hash table. 'lookup' must be the 13471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * result of an immediate previous failed _lookup_p() call 13481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * (i.e. with *lookup == NULL), and 'e' is the pointer to the 13491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * newly created entry 13501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 13511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 13521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_add_p( Cache* cache, 13531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry** lookup, 13541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e ) 13551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 13561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *lookup = e; 13571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->id = ++cache->last_id; 13581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_mru_add(e, &cache->mru_list); 13591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache->num_entries += 1; 13601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: entry %d added (count=%d)", __FUNCTION__, 13621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->id, cache->num_entries); 13631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 13641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* Remove an existing entry from the hash table, 13661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 'lookup' must be the result of an immediate previous 13671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * and succesful _lookup_p() call. 13681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 13691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 13701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_remove_p( Cache* cache, 13711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry** lookup ) 13721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 13731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e = *lookup; 13741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: entry %d removed (count=%d)", __FUNCTION__, 13761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e->id, cache->num_entries-1); 13771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_mru_remove(e); 13791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *lookup = e->hlink; 13801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_free(e); 13811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project cache->num_entries -= 1; 13821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 13831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* Remove the oldest entry from the hash table. 13851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 13861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 13871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_cache_remove_oldest( Cache* cache ) 13881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 13891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* oldest = cache->mru_list.mru_prev; 13901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry** lookup = _cache_lookup_p(cache, oldest); 13911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (*lookup == NULL) { /* should not happen */ 13931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: OLDEST NOT IN HTABLE ?", __FUNCTION__); 13941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return; 13951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 13961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _cache_remove_p(cache, lookup); 13971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 13981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 1399dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund/* Remove all expired entries from the hash table. 1400dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund */ 1401dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlundstatic void _cache_remove_expired(Cache* cache) { 1402dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund Entry* e; 1403dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund time_t now = _time_now(); 1404dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund 1405dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund for (e = cache->mru_list.mru_next; e != &cache->mru_list;) { 1406dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund // Entry is old, remove 1407dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund if (now >= e->expires) { 1408dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund Entry** lookup = _cache_lookup_p(cache, e); 1409dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund if (*lookup == NULL) { /* should not happen */ 1410dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund XLOG("%s: ENTRY NOT IN HTABLE ?", __FUNCTION__); 1411dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund return; 1412dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund } 1413dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund e = e->mru_next; 1414dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund _cache_remove_p(cache, lookup); 1415dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund } else { 1416dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund e = e->mru_next; 1417dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund } 1418dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund } 1419dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund} 14201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source ProjectResolvCacheStatus 14221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_resolv_cache_lookup( struct resolv_cache* cache, 14231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const void* query, 14241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int querylen, 14251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project void* answer, 14261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int answersize, 14271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int *answerlen ) 14281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 14291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project DnsPacket pack[1]; 14301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry key[1]; 14311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int index; 14321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry** lookup; 14331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e; 14341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project time_t now; 14351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ResolvCacheStatus result = RESOLV_CACHE_NOTFOUND; 14371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: lookup", __FUNCTION__); 14391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG_QUERY(query, querylen); 14401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* we don't cache malformed queries */ 14421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!entry_init_key(key, query, querylen)) { 14431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: unsupported query", __FUNCTION__); 14441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return RESOLV_CACHE_UNSUPPORTED; 14451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 14461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* lookup cache */ 14471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_lock( &cache->lock ); 14481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* see the description of _lookup_p to understand this. 14501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * the function always return a non-NULL pointer. 14511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 14521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lookup = _cache_lookup_p(cache, key); 14531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e = *lookup; 14541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e == NULL) { 14561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( "NOT IN CACHE"); 14571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project goto Exit; 14581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 14591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project now = _time_now(); 14611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* remove stale entries here */ 14633e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (now >= e->expires) { 14641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( " NOT IN CACHE (STALE ENTRY %p DISCARDED)", *lookup ); 14651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _cache_remove_p(cache, lookup); 14661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project goto Exit; 14671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 14681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *answerlen = e->answerlen; 14701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e->answerlen > answersize) { 14711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* NOTE: we return UNSUPPORTED if the answer buffer is too short */ 14721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project result = RESOLV_CACHE_UNSUPPORTED; 14731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG(" ANSWER TOO LONG"); 14741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project goto Exit; 14751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 14761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project memcpy( answer, e->answer, e->answerlen ); 14781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* bump up this entry to the top of the MRU list */ 14801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e != cache->mru_list.mru_next) { 14811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_mru_remove( e ); 14821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project entry_mru_add( e, &cache->mru_list ); 14831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 14841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( "FOUND IN CACHE entry=%p", e ); 14861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project result = RESOLV_CACHE_FOUND; 14871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source ProjectExit: 14891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_unlock( &cache->lock ); 14901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return result; 14911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 14921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 14941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectvoid 14951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_resolv_cache_add( struct resolv_cache* cache, 14961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const void* query, 14971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int querylen, 14981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const void* answer, 14991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int answerlen ) 15001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 15011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry key[1]; 15021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry* e; 15031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project Entry** lookup; 15043e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk u_long ttl; 15051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* don't assume that the query has already been cached 15071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 15081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (!entry_init_key( key, query, querylen )) { 15091dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( "%s: passed invalid query ?", __FUNCTION__); 15101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return; 15111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_lock( &cache->lock ); 15141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( "%s: query:", __FUNCTION__ ); 15161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG_QUERY(query,querylen); 15173e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk XLOG_ANSWER(answer, answerlen); 15181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG_DATA 15191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG( "answer:"); 15201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG_BYTES(answer,answerlen); 15211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 15221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lookup = _cache_lookup_p(cache, key); 15241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e = *lookup; 15251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e != NULL) { /* should not happen */ 15271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: ALREADY IN CACHE (%p) ? IGNORING ADD", 15281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __FUNCTION__, e); 15291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project goto Exit; 15301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15323a4910c6161d57e40ba01cc9693f1a4514892b03Mattias Falk if (cache->num_entries >= cache->max_entries) { 1533dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund _cache_remove_expired(cache); 1534dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund if (cache->num_entries >= cache->max_entries) { 1535dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund _cache_remove_oldest(cache); 1536dd16182b4b3f107d5c26015622c1cb8c06619ad7Anders Fredlund } 15371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* need to lookup again */ 15381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project lookup = _cache_lookup_p(cache, key); 15391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project e = *lookup; 15401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (e != NULL) { 15411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: ALREADY IN CACHE (%p) ? IGNORING ADD", 15421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project __FUNCTION__, e); 15431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project goto Exit; 15441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15473e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk ttl = answer_getTTL(answer, answerlen); 15483e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (ttl > 0) { 15493e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk e = entry_alloc(key, answer, answerlen); 15503e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk if (e != NULL) { 15513e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk e->expires = ttl + _time_now(); 15523e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk _cache_add_p(cache, lookup, e); 15533e0c5102e6d57e5b7296f95e1b318fda6114b48eMattias Falk } 15541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if DEBUG 15561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _cache_dump_mru(cache); 15571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 15581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source ProjectExit: 15591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_unlock( &cache->lock ); 15601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 15611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 15631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 15641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 15651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 15661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/***** *****/ 15671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 15681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/****************************************************************************/ 15691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic struct resolv_cache* _res_cache; 15711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic pthread_once_t _res_cache_once; 15721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic void 15741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_res_cache_init( void ) 15751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 15761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project const char* env = getenv(CONFIG_ENV); 15771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (env && atoi(env) == 0) { 15791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* the cache is disabled */ 15801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return; 15811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 15821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _res_cache = _resolv_cache_create(); 15841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 15851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstruct resolv_cache* 15881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project__get_res_cache( void ) 15891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 15901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_once( &_res_cache_once, _res_cache_init ); 15911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return _res_cache; 15921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 15931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectvoid 15951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project_resolv_cache_reset( unsigned generation ) 15961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 15971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project XLOG("%s: generation=%d", __FUNCTION__, generation); 15981dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 15991dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (_res_cache == NULL) 16001dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return; 16011dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 16021dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_lock( &_res_cache->lock ); 16031dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (_res_cache->generation != generation) { 16041dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _cache_flush_locked(_res_cache); 16051dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project _res_cache->generation = generation; 16061dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 16071dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project pthread_mutex_unlock( &_res_cache->lock ); 16081dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 1609