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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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