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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "net/dns/address_sorter_posix.h" | |
6 | |
7 #include <netinet/in.h> | |
8 | |
9 #if defined(OS_MACOSX) || defined(OS_BSD) | |
10 #include <sys/socket.h> // Must be included before ifaddrs.h. | |
11 #include <ifaddrs.h> | |
12 #include <net/if.h> | |
13 #include <netinet/in_var.h> | |
14 #include <string.h> | |
15 #include <sys/ioctl.h> | |
16 #endif | |
17 | |
18 #include <algorithm> | |
19 | |
20 #include "base/logging.h" | |
21 #include "base/memory/scoped_vector.h" | |
22 #include "net/socket/client_socket_factory.h" | |
23 #include "net/udp/datagram_client_socket.h" | |
24 | |
25 #if defined(OS_LINUX) | |
26 #include "net/base/address_tracker_linux.h" | |
27 #endif | |
28 | |
29 namespace net { | |
30 | |
31 namespace { | |
32 | |
33 // Address sorting is performed according to RFC3484 with revisions. | |
34 // http://tools.ietf.org/html/draft-ietf-6man-rfc3484bis-06 | |
35 // Precedence and label are separate to support override through /etc/gai.conf. | |
36 | |
37 // Returns true if |p1| should precede |p2| in the table. | |
38 // Sorts table by decreasing prefix size to allow longest prefix matching. | |
39 bool ComparePolicy(const AddressSorterPosix::PolicyEntry& p1, | |
40 const AddressSorterPosix::PolicyEntry& p2) { | |
41 return p1.prefix_length > p2.prefix_length; | |
42 } | |
43 | |
44 // Creates sorted PolicyTable from |table| with |size| entries. | |
45 AddressSorterPosix::PolicyTable LoadPolicy( | |
46 AddressSorterPosix::PolicyEntry* table, | |
47 size_t size) { | |
48 AddressSorterPosix::PolicyTable result(table, table + size); | |
49 std::sort(result.begin(), result.end(), ComparePolicy); | |
50 return result; | |
51 } | |
52 | |
53 // Search |table| for matching prefix of |address|. |table| must be sorted by | |
54 // descending prefix (prefix of another prefix must be later in table). | |
55 unsigned GetPolicyValue(const AddressSorterPosix::PolicyTable& table, | |
56 const IPAddressNumber& address) { | |
57 if (address.size() == kIPv4AddressSize) | |
58 return GetPolicyValue(table, ConvertIPv4NumberToIPv6Number(address)); | |
59 for (unsigned i = 0; i < table.size(); ++i) { | |
60 const AddressSorterPosix::PolicyEntry& entry = table[i]; | |
61 IPAddressNumber prefix(entry.prefix, entry.prefix + kIPv6AddressSize); | |
62 if (IPNumberMatchesPrefix(address, prefix, entry.prefix_length)) | |
63 return entry.value; | |
64 } | |
65 NOTREACHED(); | |
66 // The last entry is the least restrictive, so assume it's default. | |
67 return table.back().value; | |
68 } | |
69 | |
70 bool IsIPv6Multicast(const IPAddressNumber& address) { | |
71 DCHECK_EQ(kIPv6AddressSize, address.size()); | |
72 return address[0] == 0xFF; | |
73 } | |
74 | |
75 AddressSorterPosix::AddressScope GetIPv6MulticastScope( | |
76 const IPAddressNumber& address) { | |
77 DCHECK_EQ(kIPv6AddressSize, address.size()); | |
78 return static_cast<AddressSorterPosix::AddressScope>(address[1] & 0x0F); | |
79 } | |
80 | |
81 bool IsIPv6Loopback(const IPAddressNumber& address) { | |
82 DCHECK_EQ(kIPv6AddressSize, address.size()); | |
83 // IN6_IS_ADDR_LOOPBACK | |
84 unsigned char kLoopback[kIPv6AddressSize] = { | |
85 0, 0, 0, 0, 0, 0, 0, 0, | |
86 0, 0, 0, 0, 0, 0, 0, 1, | |
87 }; | |
88 return address == IPAddressNumber(kLoopback, kLoopback + kIPv6AddressSize); | |
89 } | |
90 | |
91 bool IsIPv6LinkLocal(const IPAddressNumber& address) { | |
92 DCHECK_EQ(kIPv6AddressSize, address.size()); | |
93 // IN6_IS_ADDR_LINKLOCAL | |
94 return (address[0] == 0xFE) && ((address[1] & 0xC0) == 0x80); | |
95 } | |
96 | |
97 bool IsIPv6SiteLocal(const IPAddressNumber& address) { | |
98 DCHECK_EQ(kIPv6AddressSize, address.size()); | |
99 // IN6_IS_ADDR_SITELOCAL | |
100 return (address[0] == 0xFE) && ((address[1] & 0xC0) == 0xC0); | |
101 } | |
102 | |
103 AddressSorterPosix::AddressScope GetScope( | |
104 const AddressSorterPosix::PolicyTable& ipv4_scope_table, | |
105 const IPAddressNumber& address) { | |
106 if (address.size() == kIPv6AddressSize) { | |
107 if (IsIPv6Multicast(address)) { | |
108 return GetIPv6MulticastScope(address); | |
109 } else if (IsIPv6Loopback(address) || IsIPv6LinkLocal(address)) { | |
110 return AddressSorterPosix::SCOPE_LINKLOCAL; | |
111 } else if (IsIPv6SiteLocal(address)) { | |
112 return AddressSorterPosix::SCOPE_SITELOCAL; | |
113 } else { | |
114 return AddressSorterPosix::SCOPE_GLOBAL; | |
115 } | |
116 } else if (address.size() == kIPv4AddressSize) { | |
117 return static_cast<AddressSorterPosix::AddressScope>( | |
118 GetPolicyValue(ipv4_scope_table, address)); | |
119 } else { | |
120 NOTREACHED(); | |
121 return AddressSorterPosix::SCOPE_NODELOCAL; | |
122 } | |
123 } | |
124 | |
125 // Default policy table. RFC 3484, Section 2.1. | |
126 AddressSorterPosix::PolicyEntry kDefaultPrecedenceTable[] = { | |
127 // ::1/128 -- loopback | |
128 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, 128, 50 }, | |
129 // ::/0 -- any | |
130 { { }, 0, 40 }, | |
131 // ::ffff:0:0/96 -- IPv4 mapped | |
132 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF }, 96, 35 }, | |
133 // 2002::/16 -- 6to4 | |
134 { { 0x20, 0x02, }, 16, 30 }, | |
135 // 2001::/32 -- Teredo | |
136 { { 0x20, 0x01, 0, 0 }, 32, 5 }, | |
137 // fc00::/7 -- unique local address | |
138 { { 0xFC }, 7, 3 }, | |
139 // ::/96 -- IPv4 compatible | |
140 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 96, 1 }, | |
141 // fec0::/10 -- site-local expanded scope | |
142 { { 0xFE, 0xC0 }, 10, 1 }, | |
143 // 3ffe::/16 -- 6bone | |
144 { { 0x3F, 0xFE }, 16, 1 }, | |
145 }; | |
146 | |
147 AddressSorterPosix::PolicyEntry kDefaultLabelTable[] = { | |
148 // ::1/128 -- loopback | |
149 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, 128, 0 }, | |
150 // ::/0 -- any | |
151 { { }, 0, 1 }, | |
152 // ::ffff:0:0/96 -- IPv4 mapped | |
153 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF }, 96, 4 }, | |
154 // 2002::/16 -- 6to4 | |
155 { { 0x20, 0x02, }, 16, 2 }, | |
156 // 2001::/32 -- Teredo | |
157 { { 0x20, 0x01, 0, 0 }, 32, 5 }, | |
158 // fc00::/7 -- unique local address | |
159 { { 0xFC }, 7, 13 }, | |
160 // ::/96 -- IPv4 compatible | |
161 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 96, 3 }, | |
162 // fec0::/10 -- site-local expanded scope | |
163 { { 0xFE, 0xC0 }, 10, 11 }, | |
164 // 3ffe::/16 -- 6bone | |
165 { { 0x3F, 0xFE }, 16, 12 }, | |
166 }; | |
167 | |
168 // Default mapping of IPv4 addresses to scope. | |
169 AddressSorterPosix::PolicyEntry kDefaultIPv4ScopeTable[] = { | |
170 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0x7F }, 104, | |
171 AddressSorterPosix::SCOPE_LINKLOCAL }, | |
172 { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0xA9, 0xFE }, 112, | |
173 AddressSorterPosix::SCOPE_LINKLOCAL }, | |
174 { { }, 0, AddressSorterPosix::SCOPE_GLOBAL }, | |
175 }; | |
176 | |
177 struct DestinationInfo { | |
178 IPAddressNumber address; | |
179 AddressSorterPosix::AddressScope scope; | |
180 unsigned precedence; | |
181 unsigned label; | |
182 const AddressSorterPosix::SourceAddressInfo* src; | |
183 unsigned common_prefix_length; | |
184 }; | |
185 | |
186 // Returns true iff |dst_a| should precede |dst_b| in the address list. | |
187 // RFC 3484, section 6. | |
188 bool CompareDestinations(const DestinationInfo* dst_a, | |
189 const DestinationInfo* dst_b) { | |
190 // Rule 1: Avoid unusable destinations. | |
191 // Unusable destinations are already filtered out. | |
192 DCHECK(dst_a->src); | |
193 DCHECK(dst_b->src); | |
194 | |
195 // Rule 2: Prefer matching scope. | |
196 bool scope_match1 = (dst_a->src->scope == dst_a->scope); | |
197 bool scope_match2 = (dst_b->src->scope == dst_b->scope); | |
198 if (scope_match1 != scope_match2) | |
199 return scope_match1; | |
200 | |
201 // Rule 3: Avoid deprecated addresses. | |
202 if (dst_a->src->deprecated != dst_b->src->deprecated) | |
203 return !dst_a->src->deprecated; | |
204 | |
205 // Rule 4: Prefer home addresses. | |
206 if (dst_a->src->home != dst_b->src->home) | |
207 return dst_a->src->home; | |
208 | |
209 // Rule 5: Prefer matching label. | |
210 bool label_match1 = (dst_a->src->label == dst_a->label); | |
211 bool label_match2 = (dst_b->src->label == dst_b->label); | |
212 if (label_match1 != label_match2) | |
213 return label_match1; | |
214 | |
215 // Rule 6: Prefer higher precedence. | |
216 if (dst_a->precedence != dst_b->precedence) | |
217 return dst_a->precedence > dst_b->precedence; | |
218 | |
219 // Rule 7: Prefer native transport. | |
220 if (dst_a->src->native != dst_b->src->native) | |
221 return dst_a->src->native; | |
222 | |
223 // Rule 8: Prefer smaller scope. | |
224 if (dst_a->scope != dst_b->scope) | |
225 return dst_a->scope < dst_b->scope; | |
226 | |
227 // Rule 9: Use longest matching prefix. Only for matching address families. | |
228 if (dst_a->address.size() == dst_b->address.size()) { | |
229 if (dst_a->common_prefix_length != dst_b->common_prefix_length) | |
230 return dst_a->common_prefix_length > dst_b->common_prefix_length; | |
231 } | |
232 | |
233 // Rule 10: Leave the order unchanged. | |
234 // stable_sort takes care of that. | |
235 return false; | |
236 } | |
237 | |
238 } // namespace | |
239 | |
240 AddressSorterPosix::AddressSorterPosix(ClientSocketFactory* socket_factory) | |
241 : socket_factory_(socket_factory), | |
242 precedence_table_(LoadPolicy(kDefaultPrecedenceTable, | |
243 arraysize(kDefaultPrecedenceTable))), | |
244 label_table_(LoadPolicy(kDefaultLabelTable, | |
245 arraysize(kDefaultLabelTable))), | |
246 ipv4_scope_table_(LoadPolicy(kDefaultIPv4ScopeTable, | |
247 arraysize(kDefaultIPv4ScopeTable))) { | |
248 NetworkChangeNotifier::AddIPAddressObserver(this); | |
249 OnIPAddressChanged(); | |
250 } | |
251 | |
252 AddressSorterPosix::~AddressSorterPosix() { | |
253 NetworkChangeNotifier::RemoveIPAddressObserver(this); | |
254 } | |
255 | |
256 void AddressSorterPosix::Sort(const AddressList& list, | |
257 const CallbackType& callback) const { | |
258 DCHECK(CalledOnValidThread()); | |
259 ScopedVector<DestinationInfo> sort_list; | |
260 | |
261 for (size_t i = 0; i < list.size(); ++i) { | |
262 scoped_ptr<DestinationInfo> info(new DestinationInfo()); | |
263 info->address = list[i].address(); | |
264 info->scope = GetScope(ipv4_scope_table_, info->address); | |
265 info->precedence = GetPolicyValue(precedence_table_, info->address); | |
266 info->label = GetPolicyValue(label_table_, info->address); | |
267 | |
268 // Each socket can only be bound once. | |
269 scoped_ptr<DatagramClientSocket> socket( | |
270 socket_factory_->CreateDatagramClientSocket( | |
271 DatagramSocket::DEFAULT_BIND, | |
272 RandIntCallback(), | |
273 NULL /* NetLog */, | |
274 NetLog::Source())); | |
275 | |
276 // Even though no packets are sent, cannot use port 0 in Connect. | |
277 IPEndPoint dest(info->address, 80 /* port */); | |
278 int rv = socket->Connect(dest); | |
279 if (rv != OK) { | |
280 VLOG(1) << "Could not connect to " << dest.ToStringWithoutPort() | |
281 << " reason " << rv; | |
282 continue; | |
283 } | |
284 // Filter out unusable destinations. | |
285 IPEndPoint src; | |
286 rv = socket->GetLocalAddress(&src); | |
287 if (rv != OK) { | |
288 LOG(WARNING) << "Could not get local address for " | |
289 << dest.ToStringWithoutPort() << " reason " << rv; | |
290 continue; | |
291 } | |
292 | |
293 SourceAddressInfo& src_info = source_map_[src.address()]; | |
294 if (src_info.scope == SCOPE_UNDEFINED) { | |
295 // If |source_info_| is out of date, |src| might be missing, but we still | |
296 // want to sort, even though the HostCache will be cleared soon. | |
297 FillPolicy(src.address(), &src_info); | |
298 } | |
299 info->src = &src_info; | |
300 | |
301 if (info->address.size() == src.address().size()) { | |
302 info->common_prefix_length = std::min( | |
303 CommonPrefixLength(info->address, src.address()), | |
304 info->src->prefix_length); | |
305 } | |
306 sort_list.push_back(info.release()); | |
307 } | |
308 | |
309 std::stable_sort(sort_list.begin(), sort_list.end(), CompareDestinations); | |
310 | |
311 AddressList result; | |
312 for (size_t i = 0; i < sort_list.size(); ++i) | |
313 result.push_back(IPEndPoint(sort_list[i]->address, 0 /* port */)); | |
314 | |
315 callback.Run(true, result); | |
316 } | |
317 | |
318 void AddressSorterPosix::OnIPAddressChanged() { | |
319 DCHECK(CalledOnValidThread()); | |
320 source_map_.clear(); | |
321 #if defined(OS_LINUX) | |
322 const internal::AddressTrackerLinux* tracker = | |
323 NetworkChangeNotifier::GetAddressTracker(); | |
324 if (!tracker) | |
325 return; | |
326 typedef internal::AddressTrackerLinux::AddressMap AddressMap; | |
327 AddressMap map = tracker->GetAddressMap(); | |
328 for (AddressMap::const_iterator it = map.begin(); it != map.end(); ++it) { | |
329 const IPAddressNumber& address = it->first; | |
330 const struct ifaddrmsg& msg = it->second; | |
331 SourceAddressInfo& info = source_map_[address]; | |
332 info.native = false; // TODO(szym): obtain this via netlink. | |
333 info.deprecated = msg.ifa_flags & IFA_F_DEPRECATED; | |
334 info.home = msg.ifa_flags & IFA_F_HOMEADDRESS; | |
335 info.prefix_length = msg.ifa_prefixlen; | |
336 FillPolicy(address, &info); | |
337 } | |
338 #elif defined(OS_MACOSX) || defined(OS_BSD) | |
339 // It's not clear we will receive notification when deprecated flag changes. | |
340 // Socket for ioctl. | |
341 int ioctl_socket = socket(AF_INET6, SOCK_DGRAM, 0); | |
342 if (ioctl_socket < 0) | |
343 return; | |
344 | |
345 struct ifaddrs* addrs; | |
346 int rv = getifaddrs(&addrs); | |
347 if (rv < 0) { | |
348 LOG(WARNING) << "getifaddrs failed " << rv; | |
349 close(ioctl_socket); | |
350 return; | |
351 } | |
352 | |
353 for (struct ifaddrs* ifa = addrs; ifa != NULL; ifa = ifa->ifa_next) { | |
354 IPEndPoint src; | |
355 if (!src.FromSockAddr(ifa->ifa_addr, ifa->ifa_addr->sa_len)) | |
356 continue; | |
357 SourceAddressInfo& info = source_map_[src.address()]; | |
358 // Note: no known way to fill in |native| and |home|. | |
359 info.native = info.home = info.deprecated = false; | |
360 if (ifa->ifa_addr->sa_family == AF_INET6) { | |
361 struct in6_ifreq ifr = {}; | |
362 strncpy(ifr.ifr_name, ifa->ifa_name, sizeof(ifr.ifr_name) - 1); | |
363 DCHECK_LE(ifa->ifa_addr->sa_len, sizeof(ifr.ifr_ifru.ifru_addr)); | |
364 memcpy(&ifr.ifr_ifru.ifru_addr, ifa->ifa_addr, ifa->ifa_addr->sa_len); | |
365 int rv = ioctl(ioctl_socket, SIOCGIFAFLAG_IN6, &ifr); | |
366 if (rv >= 0) { | |
367 info.deprecated = ifr.ifr_ifru.ifru_flags & IN6_IFF_DEPRECATED; | |
368 } else { | |
369 LOG(WARNING) << "SIOCGIFAFLAG_IN6 failed " << rv; | |
370 } | |
371 } | |
372 if (ifa->ifa_netmask) { | |
373 IPEndPoint netmask; | |
374 if (netmask.FromSockAddr(ifa->ifa_netmask, ifa->ifa_addr->sa_len)) { | |
375 info.prefix_length = MaskPrefixLength(netmask.address()); | |
376 } else { | |
377 LOG(WARNING) << "FromSockAddr failed on netmask"; | |
378 } | |
379 } | |
380 FillPolicy(src.address(), &info); | |
381 } | |
382 freeifaddrs(addrs); | |
383 close(ioctl_socket); | |
384 #endif | |
385 } | |
386 | |
387 void AddressSorterPosix::FillPolicy(const IPAddressNumber& address, | |
388 SourceAddressInfo* info) const { | |
389 DCHECK(CalledOnValidThread()); | |
390 info->scope = GetScope(ipv4_scope_table_, address); | |
391 info->label = GetPolicyValue(label_table_, address); | |
392 } | |
393 | |
394 // static | |
395 scoped_ptr<AddressSorter> AddressSorter::CreateAddressSorter() { | |
396 return scoped_ptr<AddressSorter>( | |
397 new AddressSorterPosix(ClientSocketFactory::GetDefaultFactory())); | |
398 } | |
399 | |
400 } // namespace net | |
401 | |
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