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      1 //* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* ***** BEGIN LICENSE BLOCK *****
      3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
      4  *
      5  * The contents of this file are subject to the Mozilla Public License Version
      6  * 1.1 (the "License"); you may not use this file except in compliance with
      7  * the License. You may obtain a copy of the License at
      8  * http://www.mozilla.org/MPL/
      9  *
     10  * Software distributed under the License is distributed on an "AS IS" basis,
     11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
     12  * for the specific language governing rights and limitations under the
     13  * License.
     14  *
     15  * The Original Code is Mozilla Effective-TLD Service
     16  *
     17  * The Initial Developer of the Original Code is
     18  * Google Inc.
     19  * Portions created by the Initial Developer are Copyright (C) 2006
     20  * the Initial Developer. All Rights Reserved.
     21  *
     22  * Contributor(s):
     23  *   Pamela Greene <pamg.bugs (at) gmail.com> (original author)
     24  *   Daniel Witte <dwitte (at) stanford.edu>
     25  *
     26  * Alternatively, the contents of this file may be used under the terms of
     27  * either the GNU General Public License Version 2 or later (the "GPL"), or
     28  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
     29  * in which case the provisions of the GPL or the LGPL are applicable instead
     30  * of those above. If you wish to allow use of your version of this file only
     31  * under the terms of either the GPL or the LGPL, and not to allow others to
     32  * use your version of this file under the terms of the MPL, indicate your
     33  * decision by deleting the provisions above and replace them with the notice
     34  * and other provisions required by the GPL or the LGPL. If you do not delete
     35  * the provisions above, a recipient may use your version of this file under
     36  * the terms of any one of the MPL, the GPL or the LGPL.
     37  *
     38  * ***** END LICENSE BLOCK ***** */
     39 
     40 #include "net/base/registry_controlled_domain.h"
     41 
     42 #include "base/logging.h"
     43 #include "base/singleton.h"
     44 #include "base/string_util.h"
     45 #include "googleurl/src/gurl.h"
     46 #include "googleurl/src/url_parse.h"
     47 #include "net/base/net_module.h"
     48 #include "net/base/net_util.h"
     49 
     50 #include "effective_tld_names.cc"
     51 
     52 namespace net {
     53 
     54 static const int kExceptionRule = 1;
     55 static const int kWildcardRule = 2;
     56 
     57 RegistryControlledDomainService::RegistryControlledDomainService()
     58     : find_domain_function_(Perfect_Hash::FindDomain) {
     59 }
     60 
     61 // static
     62 std::string RegistryControlledDomainService::GetDomainAndRegistry(
     63     const GURL& gurl) {
     64   const url_parse::Component host =
     65       gurl.parsed_for_possibly_invalid_spec().host;
     66   if ((host.len <= 0) || gurl.HostIsIPAddress())
     67     return std::string();
     68   return GetDomainAndRegistryImpl(std::string(
     69       gurl.possibly_invalid_spec().data() + host.begin, host.len));
     70 }
     71 
     72 // static
     73 std::string RegistryControlledDomainService::GetDomainAndRegistry(
     74     const std::string& host) {
     75   url_canon::CanonHostInfo host_info;
     76   const std::string canon_host(net::CanonicalizeHost(host, &host_info));
     77   if (canon_host.empty() || host_info.IsIPAddress())
     78     return std::string();
     79   return GetDomainAndRegistryImpl(canon_host);
     80 }
     81 
     82 // static
     83 std::string RegistryControlledDomainService::GetDomainAndRegistry(
     84     const std::wstring& host) {
     85   url_canon::CanonHostInfo host_info;
     86   const std::string canon_host(net::CanonicalizeHost(host, &host_info));
     87   if (canon_host.empty() || host_info.IsIPAddress())
     88     return std::string();
     89   return GetDomainAndRegistryImpl(canon_host);
     90 }
     91 
     92 // static
     93 bool RegistryControlledDomainService::SameDomainOrHost(const GURL& gurl1,
     94                                                        const GURL& gurl2) {
     95   // See if both URLs have a known domain + registry, and those values are the
     96   // same.
     97   const std::string domain1(GetDomainAndRegistry(gurl1));
     98   const std::string domain2(GetDomainAndRegistry(gurl2));
     99   if (!domain1.empty() || !domain2.empty())
    100     return domain1 == domain2;
    101 
    102   // No domains.  See if the hosts are identical.
    103   const url_parse::Component host1 =
    104       gurl1.parsed_for_possibly_invalid_spec().host;
    105   const url_parse::Component host2 =
    106       gurl2.parsed_for_possibly_invalid_spec().host;
    107   if ((host1.len <= 0) || (host1.len != host2.len))
    108     return false;
    109   return !strncmp(gurl1.possibly_invalid_spec().data() + host1.begin,
    110                   gurl2.possibly_invalid_spec().data() + host2.begin,
    111                   host1.len);
    112 }
    113 
    114 // static
    115 size_t RegistryControlledDomainService::GetRegistryLength(
    116     const GURL& gurl,
    117     bool allow_unknown_registries) {
    118   const url_parse::Component host =
    119       gurl.parsed_for_possibly_invalid_spec().host;
    120   if (host.len <= 0)
    121     return std::string::npos;
    122   if (gurl.HostIsIPAddress())
    123     return 0;
    124   return GetInstance()->GetRegistryLengthImpl(
    125       std::string(gurl.possibly_invalid_spec().data() + host.begin, host.len),
    126       allow_unknown_registries);
    127 }
    128 
    129 // static
    130 size_t RegistryControlledDomainService::GetRegistryLength(
    131     const std::string& host,
    132     bool allow_unknown_registries) {
    133   url_canon::CanonHostInfo host_info;
    134   const std::string canon_host(net::CanonicalizeHost(host, &host_info));
    135   if (canon_host.empty())
    136     return std::string::npos;
    137   if (host_info.IsIPAddress())
    138     return 0;
    139   return GetInstance()->GetRegistryLengthImpl(canon_host,
    140                                               allow_unknown_registries);
    141 }
    142 
    143 // static
    144 size_t RegistryControlledDomainService::GetRegistryLength(
    145     const std::wstring& host,
    146     bool allow_unknown_registries) {
    147   url_canon::CanonHostInfo host_info;
    148   const std::string canon_host(net::CanonicalizeHost(host, &host_info));
    149   if (canon_host.empty())
    150     return std::string::npos;
    151   if (host_info.IsIPAddress())
    152     return 0;
    153   return GetInstance()->GetRegistryLengthImpl(canon_host,
    154                                               allow_unknown_registries);
    155 }
    156 
    157 // static
    158 std::string RegistryControlledDomainService::GetDomainAndRegistryImpl(
    159     const std::string& host) {
    160   DCHECK(!host.empty());
    161 
    162   // Find the length of the registry for this host.
    163   const size_t registry_length =
    164       GetInstance()->GetRegistryLengthImpl(host, true);
    165   if ((registry_length == std::string::npos) || (registry_length == 0))
    166     return std::string();  // No registry.
    167   // The "2" in this next line is 1 for the dot, plus a 1-char minimum preceding
    168   // subcomponent length.
    169   DCHECK(host.length() >= 2);
    170   if (registry_length > (host.length() - 2)) {
    171     NOTREACHED() <<
    172         "Host does not have at least one subcomponent before registry!";
    173     return std::string();
    174   }
    175 
    176   // Move past the dot preceding the registry, and search for the next previous
    177   // dot.  Return the host from after that dot, or the whole host when there is
    178   // no dot.
    179   const size_t dot = host.rfind('.', host.length() - registry_length - 2);
    180   if (dot == std::string::npos)
    181     return host;
    182   return host.substr(dot + 1);
    183 }
    184 
    185 size_t RegistryControlledDomainService::GetRegistryLengthImpl(
    186     const std::string& host,
    187     bool allow_unknown_registries) {
    188   DCHECK(!host.empty());
    189 
    190   // Skip leading dots.
    191   const size_t host_check_begin = host.find_first_not_of('.');
    192   if (host_check_begin == std::string::npos)
    193     return 0;  // Host is only dots.
    194 
    195   // A single trailing dot isn't relevant in this determination, but does need
    196   // to be included in the final returned length.
    197   size_t host_check_len = host.length();
    198   if (host[host_check_len - 1] == '.') {
    199     --host_check_len;
    200     DCHECK(host_check_len > 0);  // If this weren't true, the host would be ".",
    201                                  // and we'd have already returned above.
    202     if (host[host_check_len - 1] == '.')
    203       return 0;  // Multiple trailing dots.
    204   }
    205 
    206   // Walk up the domain tree, most specific to least specific,
    207   // looking for matches at each level.
    208   size_t prev_start = std::string::npos;
    209   size_t curr_start = host_check_begin;
    210   size_t next_dot = host.find('.', curr_start);
    211   if (next_dot >= host_check_len)  // Catches std::string::npos as well.
    212     return 0;  // This can't have a registry + domain.
    213   while (1) {
    214     const char* domain_str = host.data() + curr_start;
    215     int domain_length = host_check_len - curr_start;
    216     const DomainRule* rule = find_domain_function_(domain_str, domain_length);
    217 
    218     // We need to compare the string after finding a match because the
    219     // no-collisions of perfect hashing only refers to items in the set.  Since
    220     // we're searching for arbitrary domains, there could be collisions.
    221     if (rule &&
    222         base::strncasecmp(domain_str, rule->name, domain_length) == 0) {
    223       // Exception rules override wildcard rules when the domain is an exact
    224       // match, but wildcards take precedence when there's a subdomain.
    225       if (rule->type == kWildcardRule && (prev_start != std::string::npos)) {
    226         // If prev_start == host_check_begin, then the host is the registry
    227         // itself, so return 0.
    228         return (prev_start == host_check_begin) ?
    229             0 : (host.length() - prev_start);
    230       }
    231 
    232       if (rule->type == kExceptionRule) {
    233         if (next_dot == std::string::npos) {
    234           // If we get here, we had an exception rule with no dots (e.g.
    235           // "!foo").  This would only be valid if we had a corresponding
    236           // wildcard rule, which would have to be "*".  But we explicitly
    237           // disallow that case, so this kind of rule is invalid.
    238           NOTREACHED() << "Invalid exception rule";
    239           return 0;
    240         }
    241         return host.length() - next_dot - 1;
    242       }
    243 
    244       // If curr_start == host_check_begin, then the host is the registry
    245       // itself, so return 0.
    246       return (curr_start == host_check_begin) ?
    247           0 : (host.length() - curr_start);
    248     }
    249 
    250     if (next_dot >= host_check_len)  // Catches std::string::npos as well.
    251       break;
    252 
    253     prev_start = curr_start;
    254     curr_start = next_dot + 1;
    255     next_dot = host.find('.', curr_start);
    256   }
    257 
    258   // No rule found in the registry.  curr_start now points to the first
    259   // character of the last subcomponent of the host, so if we allow unknown
    260   // registries, return the length of this subcomponent.
    261   return allow_unknown_registries ? (host.length() - curr_start) : 0;
    262 }
    263 
    264 static RegistryControlledDomainService* test_instance_;
    265 
    266 // static
    267 RegistryControlledDomainService* RegistryControlledDomainService::SetInstance(
    268     RegistryControlledDomainService* instance) {
    269   RegistryControlledDomainService* old_instance = test_instance_;
    270   test_instance_ = instance;
    271   return old_instance;
    272 }
    273 
    274 // static
    275 RegistryControlledDomainService* RegistryControlledDomainService::GetInstance()
    276 {
    277   if (test_instance_)
    278     return test_instance_;
    279 
    280   return Singleton<RegistryControlledDomainService>::get();
    281 }
    282 
    283 // static
    284 void RegistryControlledDomainService::UseFindDomainFunction(
    285     FindDomainPtr function) {
    286   RegistryControlledDomainService* instance = GetInstance();
    287   instance->find_domain_function_ = function;
    288 }
    289 
    290 }  // namespace net
    291