RouteController.cpp revision 5009d5ef3fbcdc69d772b528fd22184b7d605afa
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "RouteController.h" 18 19#include "Fwmark.h" 20#include "UidRanges.h" 21 22#define LOG_TAG "Netd" 23#include "log/log.h" 24#include "logwrap/logwrap.h" 25#include "resolv_netid.h" 26 27#include <arpa/inet.h> 28#include <linux/fib_rules.h> 29#include <map> 30#include <net/if.h> 31 32namespace { 33 34// BEGIN CONSTANTS -------------------------------------------------------------------------------- 35 36const uint32_t RULE_PRIORITY_VPN_OVERRIDE_SYSTEM = 10000; 37// const uint32_t RULE_PRIORITY_VPN_OVERRIDE_LOCAL = 11000; 38const uint32_t RULE_PRIORITY_SECURE_VPN = 12000; 39const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK = 13000; 40const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE = 14000; 41const uint32_t RULE_PRIORITY_LEGACY_SYSTEM = 15000; 42const uint32_t RULE_PRIORITY_LEGACY_NETWORK = 16000; 43// const uint32_t RULE_PRIORITY_LOCAL_NETWORK = 17000; 44// const uint32_t RULE_PRIORITY_TETHERING = 18000; 45const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK = 19000; 46// const uint32_t RULE_PRIORITY_BYPASSABLE_VPN = 20000; 47// const uint32_t RULE_PRIORITY_VPN_FALLTHROUGH = 21000; 48const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 22000; 49const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED = 23000; 50const uint32_t RULE_PRIORITY_UNREACHABLE = 24000; 51 52// TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not 53// upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make 54// it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert 55// that will warn us if upstream has given these values some other meaning. 56const uint16_t FRA_UID_START = 18; 57const uint16_t FRA_UID_END = 19; 58static_assert(FRA_UID_START > FRA_MAX, 59 "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. " 60 "Check that these values match what the kernel does and then update this assertion."); 61 62const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK; 63const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL; 64 65const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0}; 66 67const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6}; 68 69const char* const IP_VERSIONS[] = {"-4", "-6"}; 70 71const uid_t UID_ROOT = 0; 72const char* const OIF_NONE = NULL; 73const bool ACTION_ADD = true; 74const bool ACTION_DEL = false; 75const bool MODIFY_NON_UID_BASED_RULES = true; 76 77// Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'" 78// warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t). 79constexpr uint16_t U16_RTA_LENGTH(uint16_t x) { 80 return RTA_LENGTH(x); 81} 82 83// These are practically const, but can't be declared so, because they are used to initialize 84// non-const pointers ("void* iov_base") in iovec arrays. 85rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY }; 86rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE }; 87rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK }; 88rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK }; 89rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START }; 90rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END }; 91 92rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE }; 93rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF }; 94 95uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0}; 96 97// END CONSTANTS ---------------------------------------------------------------------------------- 98 99std::map<std::string, uint32_t> interfaceToIndex; 100 101uint32_t getRouteTableForInterface(const char* interface) { 102 uint32_t index = if_nametoindex(interface); 103 if (index) { 104 interfaceToIndex[interface] = index; 105 } else { 106 // If the interface goes away if_nametoindex() will return 0 but we still need to know 107 // the index so we can remove the rules and routes. 108 auto iter = interfaceToIndex.find(interface); 109 if (iter == interfaceToIndex.end()) { 110 ALOGE("cannot find interface %s", interface); 111 return RT_TABLE_UNSPEC; 112 } 113 index = iter->second; 114 } 115 return index + RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX; 116} 117 118// Sends a netlink request and expects an ack. 119// |iov| is an array of struct iovec that contains the netlink message payload. 120// The netlink header is generated by this function based on |action| and |flags|. 121// Returns -errno if there was an error or if the kernel reported an error. 122WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { 123 nlmsghdr nlmsg = { 124 .nlmsg_type = action, 125 .nlmsg_flags = flags, 126 }; 127 iov[0].iov_base = &nlmsg; 128 iov[0].iov_len = sizeof(nlmsg); 129 for (int i = 0; i < iovlen; ++i) { 130 nlmsg.nlmsg_len += iov[i].iov_len; 131 } 132 133 int ret; 134 struct { 135 nlmsghdr msg; 136 nlmsgerr err; 137 } response; 138 139 int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); 140 if (sock != -1 && 141 connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), 142 sizeof(NETLINK_ADDRESS)) != -1 && 143 writev(sock, iov, iovlen) != -1 && 144 (ret = recv(sock, &response, sizeof(response), 0)) != -1) { 145 if (ret == sizeof(response)) { 146 ret = response.err.error; // Netlink errors are negative errno. 147 if (ret) { 148 ALOGE("netlink response contains error (%s)", strerror(-ret)); 149 } 150 } else { 151 ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response)); 152 ret = -EBADMSG; 153 } 154 } else { 155 ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno)); 156 ret = -errno; 157 } 158 159 if (sock != -1) { 160 close(sock); 161 } 162 163 return ret; 164} 165 166// Adds or removes a routing rule for IPv4 and IPv6. 167// 168// + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the rule 169// returns ENETUNREACH. 170// + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is 171// ignored. 172// + If |interface| is non-NULL, the rule matches the specified outgoing interface. 173// 174// Returns 0 on success or negative errno on failure. 175WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table, 176 uint32_t fwmark, uint32_t mask, const char* interface, 177 uid_t uidStart, uid_t uidEnd) { 178 // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask. 179 if (fwmark & ~mask) { 180 ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark); 181 return -ERANGE; 182 } 183 184 // The interface name must include exactly one terminating NULL and be properly padded, or older 185 // kernels will refuse to delete rules. 186 uint16_t paddingLength = 0; 187 size_t interfaceLength = 0; 188 char oifname[IFNAMSIZ]; 189 if (interface != OIF_NONE) { 190 interfaceLength = strlcpy(oifname, interface, IFNAMSIZ) + 1; 191 if (interfaceLength > IFNAMSIZ) { 192 ALOGE("interface name too long (%zu > %u)", interfaceLength, IFNAMSIZ); 193 return -ENAMETOOLONG; 194 } 195 paddingLength = RTA_SPACE(interfaceLength) - RTA_LENGTH(interfaceLength); 196 } 197 198 // Either both start and end UID must be specified, or neither. 199 if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) { 200 ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd); 201 return -EUSERS; 202 } 203 bool isUidRule = (uidStart != INVALID_UID); 204 205 // Assemble a rule request and put it in an array of iovec structures. 206 fib_rule_hdr rule = { 207 .action = static_cast<uint8_t>(table != RT_TABLE_UNSPEC ? FR_ACT_TO_TBL : 208 FR_ACT_UNREACHABLE), 209 }; 210 211 rtattr fraOifname = { U16_RTA_LENGTH(interfaceLength), FRA_OIFNAME }; 212 213 iovec iov[] = { 214 { NULL, 0 }, 215 { &rule, sizeof(rule) }, 216 { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) }, 217 { &priority, sizeof(priority) }, 218 { &FRATTR_TABLE, table != RT_TABLE_UNSPEC ? sizeof(FRATTR_TABLE) : 0 }, 219 { &table, table != RT_TABLE_UNSPEC ? sizeof(table) : 0 }, 220 { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 }, 221 { &fwmark, mask ? sizeof(fwmark) : 0 }, 222 { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 }, 223 { &mask, mask ? sizeof(mask) : 0 }, 224 { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 }, 225 { &uidStart, isUidRule ? sizeof(uidStart) : 0 }, 226 { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 }, 227 { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 }, 228 { &fraOifname, interface != OIF_NONE ? sizeof(fraOifname) : 0 }, 229 { oifname, interfaceLength }, 230 { PADDING_BUFFER, paddingLength }, 231 }; 232 233 uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS; 234 for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) { 235 rule.family = AF_FAMILIES[i]; 236 if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) { 237 return ret; 238 } 239 } 240 241 return 0; 242} 243 244// Adds or deletes an IPv4 or IPv6 route. 245// Returns 0 on success or negative errno on failure. 246WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface, 247 const char* destination, const char* nexthop) { 248 // At least the destination must be non-null. 249 if (!destination) { 250 ALOGE("null destination"); 251 return -EFAULT; 252 } 253 254 // Parse the prefix. 255 uint8_t rawAddress[sizeof(in6_addr)]; 256 uint8_t family; 257 uint8_t prefixLength; 258 int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress), 259 &prefixLength); 260 if (rawLength < 0) { 261 ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength)); 262 return rawLength; 263 } 264 265 if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) { 266 ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress)); 267 return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6. 268 } 269 270 // If an interface was specified, find the ifindex. 271 uint32_t ifindex; 272 if (interface != OIF_NONE) { 273 ifindex = if_nametoindex(interface); 274 if (!ifindex) { 275 ALOGE("cannot find interface %s", interface); 276 return -ENODEV; 277 } 278 } 279 280 // If a nexthop was specified, parse it as the same family as the prefix. 281 uint8_t rawNexthop[sizeof(in6_addr)]; 282 if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) { 283 ALOGE("inet_pton failed for nexthop %s", nexthop); 284 return -EINVAL; 285 } 286 287 // Assemble a rtmsg and put it in an array of iovec structures. 288 rtmsg route = { 289 .rtm_protocol = RTPROT_STATIC, 290 .rtm_type = RTN_UNICAST, 291 .rtm_family = family, 292 .rtm_dst_len = prefixLength, 293 }; 294 295 rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST }; 296 rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY }; 297 298 iovec iov[] = { 299 { NULL, 0 }, 300 { &route, sizeof(route) }, 301 { &RTATTR_TABLE, sizeof(RTATTR_TABLE) }, 302 { &table, sizeof(table) }, 303 { &rtaDst, sizeof(rtaDst) }, 304 { rawAddress, static_cast<size_t>(rawLength) }, 305 { &RTATTR_OIF, interface != OIF_NONE ? sizeof(RTATTR_OIF) : 0 }, 306 { &ifindex, interface != OIF_NONE ? sizeof(ifindex) : 0 }, 307 { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 }, 308 { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 }, 309 }; 310 311 uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS : 312 NETLINK_REQUEST_FLAGS; 313 return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov)); 314} 315 316// Add rules to allow legacy routes added through the requestRouteToHost() API. 317WARN_UNUSED_RESULT int AddLegacyRouteRules() { 318 Fwmark fwmark; 319 Fwmark mask; 320 321 fwmark.explicitlySelected = false; 322 mask.explicitlySelected = true; 323 324 // Rules to allow legacy routes to override the default network. 325 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_SYSTEM, 326 RouteController::ROUTE_TABLE_LEGACY_SYSTEM, fwmark.intValue, 327 mask.intValue, OIF_NONE, INVALID_UID, INVALID_UID)) { 328 return ret; 329 } 330 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK, 331 RouteController::ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, 332 mask.intValue, OIF_NONE, INVALID_UID, INVALID_UID)) { 333 return ret; 334 } 335 336 fwmark.permission = PERMISSION_SYSTEM; 337 mask.permission = PERMISSION_SYSTEM; 338 339 // A rule to allow legacy routes from system apps to override VPNs. 340 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDE_SYSTEM, 341 RouteController::ROUTE_TABLE_LEGACY_SYSTEM, fwmark.intValue, mask.intValue, 342 OIF_NONE, INVALID_UID, INVALID_UID); 343} 344 345// Add a new rule to look up the 'main' table, with the same selectors as the "default network" 346// rule, but with a lower priority. Since the default network rule points to a table with a default 347// route, the rule we're adding will never be used for normal routing lookups. However, the kernel 348// may fall-through to it to find directly-connected routes when it validates that a nexthop (in a 349// route being added) is reachable. 350WARN_UNUSED_RESULT int AddDirectlyConnectedRule() { 351 Fwmark fwmark; 352 Fwmark mask; 353 354 fwmark.netId = NETID_UNSET; 355 mask.netId = FWMARK_NET_ID_MASK; 356 357 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_DIRECTLY_CONNECTED, RT_TABLE_MAIN, 358 fwmark.intValue, mask.intValue, OIF_NONE, UID_ROOT, UID_ROOT); 359} 360 361// Add a rule to preempt the pre-defined "from all lookup main" rule. Packets that reach this rule 362// will be null-routed, and won't fall-through to the main table. 363WARN_UNUSED_RESULT int AddUnreachableRule() { 364 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, RT_TABLE_UNSPEC, MARK_UNSET, 365 MARK_UNSET, OIF_NONE, INVALID_UID, INVALID_UID); 366} 367 368// An iptables rule to mark incoming packets on a network with the netId of the network. 369// 370// This is so that the kernel can: 371// + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, ping 372// replies, SYN-ACKs, etc). 373// + Mark sockets that accept connections from this interface so that the connection stays on the 374// same interface. 375WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface, 376 Permission permission, bool add) { 377 Fwmark fwmark; 378 379 fwmark.netId = netId; 380 fwmark.explicitlySelected = true; 381 fwmark.protectedFromVpn = true; 382 fwmark.permission = permission; 383 384 char markString[UINT32_HEX_STRLEN]; 385 snprintf(markString, sizeof(markString), "0x%x", fwmark.intValue); 386 387 if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j", 388 "MARK", "--set-mark", markString, NULL)) { 389 ALOGE("failed to change iptables rule that sets incoming packet mark"); 390 return -EREMOTEIO; 391 } 392 393 return 0; 394} 395 396// A rule to route traffic based on an explicitly chosen network. 397// 398// Supports apps that use the multinetwork APIs to restrict their traffic to a network. 399// 400// Even though we check permissions at the time we set a netId into the fwmark of a socket, we need 401// to check it again in the rules here, because a network's permissions may have been updated via 402// modifyNetworkPermission(). 403WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table, 404 Permission permission, uid_t uidStart, 405 uid_t uidEnd, bool add) { 406 Fwmark fwmark; 407 Fwmark mask; 408 409 fwmark.netId = netId; 410 mask.netId = FWMARK_NET_ID_MASK; 411 412 fwmark.explicitlySelected = true; 413 mask.explicitlySelected = true; 414 415 fwmark.permission = permission; 416 mask.permission = permission; 417 418 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table, 419 fwmark.intValue, mask.intValue, OIF_NONE, uidStart, uidEnd); 420} 421 422// A rule to route traffic based on a chosen outgoing interface. 423// 424// Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already knows 425// the outgoing interface (typically for link-local communications). 426WARN_UNUSED_RESULT int modifyOutputInterfaceRule(const char* interface, uint32_t table, 427 Permission permission, uid_t uidStart, 428 uid_t uidEnd, bool add) { 429 Fwmark fwmark; 430 Fwmark mask; 431 432 fwmark.permission = permission; 433 mask.permission = permission; 434 435 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table, 436 fwmark.intValue, mask.intValue, interface, uidStart, uidEnd); 437} 438 439// A rule to route traffic based on the chosen network. 440// 441// This is for sockets that have not explicitly requested a particular network, but have been 442// bound to one when they called connect(). This ensures that sockets connected on a particular 443// network stay on that network even if the default network changes. 444WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table, 445 Permission permission, bool add) { 446 Fwmark fwmark; 447 Fwmark mask; 448 449 fwmark.netId = netId; 450 mask.netId = FWMARK_NET_ID_MASK; 451 452 fwmark.explicitlySelected = false; 453 mask.explicitlySelected = true; 454 455 fwmark.permission = permission; 456 mask.permission = permission; 457 458 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table, 459 fwmark.intValue, mask.intValue, OIF_NONE, INVALID_UID, INVALID_UID); 460} 461 462// A rule to route all traffic from a given set of UIDs to go over the VPN. 463// 464// Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket may 465// have, if they are subject to this VPN, their traffic has to go through it. Allows the traffic to 466// bypass the VPN if the protectedFromVpn bit is set. 467WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd, 468 bool add) { 469 Fwmark fwmark; 470 Fwmark mask; 471 472 fwmark.protectedFromVpn = false; 473 mask.protectedFromVpn = true; 474 475 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_SECURE_VPN, table, 476 fwmark.intValue, mask.intValue, OIF_NONE, uidStart, uidEnd); 477} 478 479// A rule to allow system apps to send traffic over this VPN even if they are not part of the target 480// set of UIDs. 481// 482// This is needed for DnsProxyListener to correctly resolve a request for a user who is in the 483// target set, but where the DnsProxyListener itself is not. 484WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool add) { 485 Fwmark fwmark; 486 Fwmark mask; 487 488 fwmark.netId = netId; 489 mask.netId = FWMARK_NET_ID_MASK; 490 491 fwmark.permission = PERMISSION_SYSTEM; 492 mask.permission = PERMISSION_SYSTEM; 493 494 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_SECURE_VPN, table, 495 fwmark.intValue, mask.intValue, OIF_NONE, INVALID_UID, INVALID_UID); 496} 497 498WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface, 499 Permission permission, bool add) { 500 uint32_t table = getRouteTableForInterface(interface); 501 if (table == RT_TABLE_UNSPEC) { 502 return -ESRCH; 503 } 504 505 if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) { 506 return ret; 507 } 508 if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID, 509 add)) { 510 return ret; 511 } 512 if (int ret = modifyOutputInterfaceRule(interface, table, permission, INVALID_UID, INVALID_UID, 513 add)) { 514 return ret; 515 } 516 return modifyImplicitNetworkRule(netId, table, permission, add); 517} 518 519WARN_UNUSED_RESULT int modifyVirtualNetwork(unsigned netId, const char* interface, 520 const UidRanges& uidRanges, bool add, 521 bool modifyNonUidBasedRules) { 522 uint32_t table = getRouteTableForInterface(interface); 523 if (table == RT_TABLE_UNSPEC) { 524 return -ESRCH; 525 } 526 527 for (const std::pair<uid_t, uid_t>& range : uidRanges.getRanges()) { 528 if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.first, 529 range.second, add)) { 530 return ret; 531 } 532 if (int ret = modifyOutputInterfaceRule(interface, table, PERMISSION_NONE, range.first, 533 range.second, add)) { 534 return ret; 535 } 536 if (int ret = modifyVpnUidRangeRule(table, range.first, range.second, add)) { 537 return ret; 538 } 539 } 540 541 if (modifyNonUidBasedRules) { 542 if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) { 543 return ret; 544 } 545 if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, 546 add)) { 547 return ret; 548 } 549 return modifyVpnSystemPermissionRule(netId, table, add); 550 } 551 552 return 0; 553} 554 555WARN_UNUSED_RESULT int modifyDefaultNetwork(uint16_t action, const char* interface, 556 Permission permission) { 557 uint32_t table = getRouteTableForInterface(interface); 558 if (table == RT_TABLE_UNSPEC) { 559 return -ESRCH; 560 } 561 562 Fwmark fwmark; 563 Fwmark mask; 564 565 fwmark.netId = NETID_UNSET; 566 mask.netId = FWMARK_NET_ID_MASK; 567 568 fwmark.permission = permission; 569 mask.permission = permission; 570 571 return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue, 572 mask.intValue, OIF_NONE, INVALID_UID, INVALID_UID); 573} 574 575// Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected 576// route, to the main table as well. 577// Returns 0 on success or negative errno on failure. 578WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination, 579 const char* nexthop, RouteController::TableType tableType) { 580 uint32_t table; 581 switch (tableType) { 582 case RouteController::INTERFACE: { 583 table = getRouteTableForInterface(interface); 584 if (table == RT_TABLE_UNSPEC) { 585 return -ESRCH; 586 } 587 break; 588 } 589 case RouteController::LEGACY_NETWORK: { 590 table = RouteController::ROUTE_TABLE_LEGACY_NETWORK; 591 break; 592 } 593 case RouteController::LEGACY_SYSTEM: { 594 table = RouteController::ROUTE_TABLE_LEGACY_SYSTEM; 595 break; 596 } 597 } 598 599 int ret = modifyIpRoute(action, table, interface, destination, nexthop); 600 // We allow apps to call requestRouteToHost() multiple times with the same route, so ignore 601 // EEXIST failures when adding routes to legacy tables. 602 if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST && 603 tableType != RouteController::INTERFACE)) { 604 return ret; 605 } 606 607 // If there's no nexthop, this is a directly connected route. Add it to the main table also, to 608 // let the kernel find it when validating nexthops when global routes are added. 609 if (!nexthop) { 610 ret = modifyIpRoute(action, RT_TABLE_MAIN, interface, destination, NULL); 611 // A failure with action == ADD && errno == EEXIST means that the route already exists in 612 // the main table, perhaps because the kernel added it automatically as part of adding the 613 // IP address to the interface. Ignore this, but complain about everything else. 614 if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST)) { 615 return ret; 616 } 617 } 618 619 return 0; 620} 621 622// Returns 0 on success or negative errno on failure. 623WARN_UNUSED_RESULT int flushRoutes(const char* interface) { 624 uint32_t table = getRouteTableForInterface(interface); 625 if (table == RT_TABLE_UNSPEC) { 626 return -ESRCH; 627 } 628 629 char tableString[UINT32_STRLEN]; 630 snprintf(tableString, sizeof(tableString), "%u", table); 631 632 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) { 633 const char* argv[] = { 634 IP_PATH, 635 IP_VERSIONS[i], 636 "route", 637 "flush", 638 "table", 639 tableString, 640 }; 641 if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) { 642 ALOGE("failed to flush routes"); 643 return -EREMOTEIO; 644 } 645 } 646 647 interfaceToIndex.erase(interface); 648 return 0; 649} 650 651} // namespace 652 653int RouteController::Init() { 654 if (int ret = AddDirectlyConnectedRule()) { 655 return ret; 656 } 657 658 if (int ret = AddLegacyRouteRules()) { 659 return ret; 660 } 661 // TODO: Enable once we are sure everything works. 662 if (false) { 663 return AddUnreachableRule(); 664 } 665 return 0; 666} 667 668int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface, 669 Permission permission) { 670 return modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD); 671} 672 673int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface, 674 Permission permission) { 675 if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) { 676 return ret; 677 } 678 return flushRoutes(interface); 679} 680 681int RouteController::addInterfaceToVirtualNetwork(unsigned netId, const char* interface, 682 const UidRanges& uidRanges) { 683 return modifyVirtualNetwork(netId, interface, uidRanges, ACTION_ADD, 684 MODIFY_NON_UID_BASED_RULES); 685} 686 687int RouteController::removeInterfaceFromVirtualNetwork(unsigned netId, const char* interface, 688 const UidRanges& uidRanges) { 689 if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, ACTION_DEL, 690 MODIFY_NON_UID_BASED_RULES)) { 691 return ret; 692 } 693 return flushRoutes(interface); 694} 695 696int RouteController::modifyPhysicalNetworkPermission(unsigned netId, const char* interface, 697 Permission oldPermission, 698 Permission newPermission) { 699 // Add the new rules before deleting the old ones, to avoid race conditions. 700 if (int ret = modifyPhysicalNetwork(netId, interface, newPermission, ACTION_ADD)) { 701 return ret; 702 } 703 return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL); 704} 705 706int RouteController::addUsersToVirtualNetwork(unsigned netId, const char* interface, 707 const UidRanges& uidRanges) { 708 return modifyVirtualNetwork(netId, interface, uidRanges, ACTION_ADD, 709 !MODIFY_NON_UID_BASED_RULES); 710} 711 712int RouteController::removeUsersFromVirtualNetwork(unsigned netId, const char* interface, 713 const UidRanges& uidRanges) { 714 return modifyVirtualNetwork(netId, interface, uidRanges, ACTION_DEL, 715 !MODIFY_NON_UID_BASED_RULES); 716} 717 718int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) { 719 return modifyDefaultNetwork(RTM_NEWRULE, interface, permission); 720} 721 722int RouteController::removeInterfaceFromDefaultNetwork(const char* interface, 723 Permission permission) { 724 return modifyDefaultNetwork(RTM_DELRULE, interface, permission); 725} 726 727int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop, 728 TableType tableType) { 729 return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType); 730} 731 732int RouteController::removeRoute(const char* interface, const char* destination, 733 const char* nexthop, TableType tableType) { 734 return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType); 735} 736