2 * Copyright (C) 2014 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #include "RouteController.h"
19 #include <arpa/inet.h>
22 #include <linux/fib_rules.h>
29 #include "UidRanges.h"
31 #define LOG_TAG "Netd"
33 #include "logwrap/logwrap.h"
34 #include "resolv_netid.h"
38 // BEGIN CONSTANTS --------------------------------------------------------------------------------
40 const uint32_t RULE_PRIORITY_VPN_OVERRIDE_SYSTEM = 10000;
41 const uint32_t RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000;
42 const uint32_t RULE_PRIORITY_SECURE_VPN = 12000;
43 const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK = 13000;
44 const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE = 14000;
45 const uint32_t RULE_PRIORITY_LEGACY_SYSTEM = 15000;
46 const uint32_t RULE_PRIORITY_LEGACY_NETWORK = 16000;
47 const uint32_t RULE_PRIORITY_LOCAL_NETWORK = 17000;
48 const uint32_t RULE_PRIORITY_TETHERING = 18000;
49 const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK = 19000;
50 const uint32_t RULE_PRIORITY_BYPASSABLE_VPN = 20000;
51 const uint32_t RULE_PRIORITY_VPN_FALLTHROUGH = 21000;
52 const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 22000;
53 const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED = 23000;
54 const uint32_t RULE_PRIORITY_UNREACHABLE = 32000;
56 const uint32_t ROUTE_TABLE_LOCAL_NETWORK = 97;
57 const uint32_t ROUTE_TABLE_LEGACY_NETWORK = 98;
58 const uint32_t ROUTE_TABLE_LEGACY_SYSTEM = 99;
60 const char* const ROUTE_TABLE_NAME_LOCAL_NETWORK = "local_network";
61 const char* const ROUTE_TABLE_NAME_LEGACY_NETWORK = "legacy_network";
62 const char* const ROUTE_TABLE_NAME_LEGACY_SYSTEM = "legacy_system";
64 const char* const ROUTE_TABLE_NAME_LOCAL = "local";
65 const char* const ROUTE_TABLE_NAME_MAIN = "main";
67 // TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not
68 // upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make
69 // it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert
70 // that will warn us if upstream has given these values some other meaning.
71 const uint16_t FRA_UID_START = 18;
72 const uint16_t FRA_UID_END = 19;
73 static_assert(FRA_UID_START > FRA_MAX,
74 "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. "
75 "Check that these values match what the kernel does and then update this assertion.");
77 const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK;
78 const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL;
80 const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0};
82 const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6};
84 const char* const IP_VERSIONS[] = {"-4", "-6"};
86 const uid_t UID_ROOT = 0;
87 const char* const IIF_NONE = NULL;
88 const char* const OIF_NONE = NULL;
89 const bool ACTION_ADD = true;
90 const bool ACTION_DEL = false;
91 const bool MODIFY_NON_UID_BASED_RULES = true;
93 const char* const RT_TABLES_PATH = "/data/misc/net/rt_tables";
94 const int RT_TABLES_FLAGS = O_CREAT | O_TRUNC | O_WRONLY | O_NOFOLLOW | O_CLOEXEC;
95 const mode_t RT_TABLES_MODE = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; // mode 0644, rw-r--r--
97 const unsigned ROUTE_FLUSH_ATTEMPTS = 2;
99 // Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'"
100 // warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t).
101 constexpr uint16_t U16_RTA_LENGTH(uint16_t x) {
102 return RTA_LENGTH(x);
105 // These are practically const, but can't be declared so, because they are used to initialize
106 // non-const pointers ("void* iov_base") in iovec arrays.
107 rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY };
108 rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE };
109 rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK };
110 rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK };
111 rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START };
112 rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END };
114 rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE };
115 rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF };
117 uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0};
119 // END CONSTANTS ----------------------------------------------------------------------------------
121 // No locks needed because RouteController is accessed only from one thread (in CommandListener).
122 std::map<std::string, uint32_t> interfaceToTable;
124 uint32_t getRouteTableForInterface(const char* interface) {
125 uint32_t index = if_nametoindex(interface);
127 index += RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX;
128 interfaceToTable[interface] = index;
131 // If the interface goes away if_nametoindex() will return 0 but we still need to know
132 // the index so we can remove the rules and routes.
133 auto iter = interfaceToTable.find(interface);
134 if (iter == interfaceToTable.end()) {
135 ALOGE("cannot find interface %s", interface);
136 return RT_TABLE_UNSPEC;
141 void addTableName(uint32_t table, const std::string& name, std::string* contents) {
142 char tableString[UINT32_STRLEN];
143 snprintf(tableString, sizeof(tableString), "%u", table);
144 *contents += tableString;
150 // Doesn't return success/failure as the file is optional; it's okay if we fail to update it.
151 void updateTableNamesFile() {
152 std::string contents;
154 addTableName(RT_TABLE_LOCAL, ROUTE_TABLE_NAME_LOCAL, &contents);
155 addTableName(RT_TABLE_MAIN, ROUTE_TABLE_NAME_MAIN, &contents);
157 addTableName(ROUTE_TABLE_LOCAL_NETWORK, ROUTE_TABLE_NAME_LOCAL_NETWORK, &contents);
158 addTableName(ROUTE_TABLE_LEGACY_NETWORK, ROUTE_TABLE_NAME_LEGACY_NETWORK, &contents);
159 addTableName(ROUTE_TABLE_LEGACY_SYSTEM, ROUTE_TABLE_NAME_LEGACY_SYSTEM, &contents);
161 for (const auto& entry : interfaceToTable) {
162 addTableName(entry.second, entry.first, &contents);
165 int fd = open(RT_TABLES_PATH, RT_TABLES_FLAGS, RT_TABLES_MODE);
167 ALOGE("failed to create %s (%s)", RT_TABLES_PATH, strerror(errno));
170 // File creation is affected by umask, so make sure the right mode bits are set.
171 if (fchmod(fd, RT_TABLES_MODE) == -1) {
172 ALOGE("failed to set mode 0%o on %s (%s)", RT_TABLES_MODE, RT_TABLES_PATH, strerror(errno));
174 ssize_t bytesWritten = write(fd, contents.data(), contents.size());
175 if (bytesWritten != static_cast<ssize_t>(contents.size())) {
176 ALOGE("failed to write to %s (%zd vs %zu bytes) (%s)", RT_TABLES_PATH, bytesWritten,
177 contents.size(), strerror(errno));
182 // Sends a netlink request and expects an ack.
183 // |iov| is an array of struct iovec that contains the netlink message payload.
184 // The netlink header is generated by this function based on |action| and |flags|.
185 // Returns -errno if there was an error or if the kernel reported an error.
186 WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) {
188 .nlmsg_type = action,
189 .nlmsg_flags = flags,
191 iov[0].iov_base = &nlmsg;
192 iov[0].iov_len = sizeof(nlmsg);
193 for (int i = 0; i < iovlen; ++i) {
194 nlmsg.nlmsg_len += iov[i].iov_len;
203 int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
205 connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS),
206 sizeof(NETLINK_ADDRESS)) != -1 &&
207 writev(sock, iov, iovlen) != -1 &&
208 (ret = recv(sock, &response, sizeof(response), 0)) != -1) {
209 if (ret == sizeof(response)) {
210 ret = response.err.error; // Netlink errors are negative errno.
212 ALOGE("netlink response contains error (%s)", strerror(-ret));
215 ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response));
219 ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno));
230 // Returns 0 on success or negative errno on failure.
231 int padInterfaceName(const char* input, char* name, size_t* length, uint16_t* padding) {
237 *length = strlcpy(name, input, IFNAMSIZ) + 1;
238 if (*length > IFNAMSIZ) {
239 ALOGE("interface name too long (%zu > %u)", *length, IFNAMSIZ);
240 return -ENAMETOOLONG;
242 *padding = RTA_SPACE(*length) - RTA_LENGTH(*length);
246 // Adds or removes a routing rule for IPv4 and IPv6.
248 // + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the rule
249 // returns ENETUNREACH.
250 // + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is
252 // + If |iif| is non-NULL, the rule matches the specified incoming interface.
253 // + If |oif| is non-NULL, the rule matches the specified outgoing interface.
254 // + If |uidStart| and |uidEnd| are not INVALID_UID, the rule matches packets from UIDs in that
255 // range (inclusive). Otherwise, the rule matches packets from all UIDs.
257 // Returns 0 on success or negative errno on failure.
258 WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
259 uint32_t fwmark, uint32_t mask, const char* iif,
260 const char* oif, uid_t uidStart, uid_t uidEnd) {
261 // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask.
262 if (fwmark & ~mask) {
263 ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark);
267 // Interface names must include exactly one terminating NULL and be properly padded, or older
268 // kernels will refuse to delete rules.
269 char iifName[IFNAMSIZ], oifName[IFNAMSIZ];
270 size_t iifLength, oifLength;
271 uint16_t iifPadding, oifPadding;
272 if (int ret = padInterfaceName(iif, iifName, &iifLength, &iifPadding)) {
275 if (int ret = padInterfaceName(oif, oifName, &oifLength, &oifPadding)) {
279 // Either both start and end UID must be specified, or neither.
280 if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) {
281 ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd);
284 bool isUidRule = (uidStart != INVALID_UID);
286 // Assemble a rule request and put it in an array of iovec structures.
287 fib_rule_hdr rule = {
288 .action = static_cast<uint8_t>(table != RT_TABLE_UNSPEC ? FR_ACT_TO_TBL :
292 rtattr fraIifName = { U16_RTA_LENGTH(iifLength), FRA_IIFNAME };
293 rtattr fraOifName = { U16_RTA_LENGTH(oifLength), FRA_OIFNAME };
297 { &rule, sizeof(rule) },
298 { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) },
299 { &priority, sizeof(priority) },
300 { &FRATTR_TABLE, table != RT_TABLE_UNSPEC ? sizeof(FRATTR_TABLE) : 0 },
301 { &table, table != RT_TABLE_UNSPEC ? sizeof(table) : 0 },
302 { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 },
303 { &fwmark, mask ? sizeof(fwmark) : 0 },
304 { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 },
305 { &mask, mask ? sizeof(mask) : 0 },
306 { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 },
307 { &uidStart, isUidRule ? sizeof(uidStart) : 0 },
308 { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 },
309 { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 },
310 { &fraIifName, iif != IIF_NONE ? sizeof(fraIifName) : 0 },
311 { iifName, iifLength },
312 { PADDING_BUFFER, iifPadding },
313 { &fraOifName, oif != OIF_NONE ? sizeof(fraOifName) : 0 },
314 { oifName, oifLength },
315 { PADDING_BUFFER, oifPadding },
318 uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS;
319 for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) {
320 rule.family = AF_FAMILIES[i];
321 if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) {
329 WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
330 uint32_t fwmark, uint32_t mask) {
331 return modifyIpRule(action, priority, table, fwmark, mask, IIF_NONE, OIF_NONE, INVALID_UID,
335 // Adds or deletes an IPv4 or IPv6 route.
336 // Returns 0 on success or negative errno on failure.
337 WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface,
338 const char* destination, const char* nexthop) {
339 // At least the destination must be non-null.
341 ALOGE("null destination");
346 uint8_t rawAddress[sizeof(in6_addr)];
348 uint8_t prefixLength;
349 int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress),
352 ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength));
356 if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) {
357 ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress));
358 return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6.
361 uint8_t type = RTN_UNICAST;
363 uint8_t rawNexthop[sizeof(in6_addr)];
365 if (nexthop && !strcmp(nexthop, "unreachable")) {
366 type = RTN_UNREACHABLE;
367 // 'interface' is likely non-NULL, as the caller (modifyRoute()) likely used it to lookup
368 // the table number. But it's an error to specify an interface ("dev ...") or a nexthop for
369 // unreachable routes, so nuke them. (IPv6 allows them to be specified; IPv4 doesn't.)
370 interface = OIF_NONE;
372 } else if (nexthop && !strcmp(nexthop, "throw")) {
374 interface = OIF_NONE;
377 // If an interface was specified, find the ifindex.
378 if (interface != OIF_NONE) {
379 ifindex = if_nametoindex(interface);
381 ALOGE("cannot find interface %s", interface);
386 // If a nexthop was specified, parse it as the same family as the prefix.
387 if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) {
388 ALOGE("inet_pton failed for nexthop %s", nexthop);
393 // Assemble a rtmsg and put it in an array of iovec structures.
395 .rtm_protocol = RTPROT_STATIC,
397 .rtm_family = family,
398 .rtm_dst_len = prefixLength,
399 .rtm_scope = static_cast<uint8_t>(nexthop ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK),
402 rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST };
403 rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY };
407 { &route, sizeof(route) },
408 { &RTATTR_TABLE, sizeof(RTATTR_TABLE) },
409 { &table, sizeof(table) },
410 { &rtaDst, sizeof(rtaDst) },
411 { rawAddress, static_cast<size_t>(rawLength) },
412 { &RTATTR_OIF, interface != OIF_NONE ? sizeof(RTATTR_OIF) : 0 },
413 { &ifindex, interface != OIF_NONE ? sizeof(ifindex) : 0 },
414 { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 },
415 { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 },
418 uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS :
419 NETLINK_REQUEST_FLAGS;
420 return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov));
423 // An iptables rule to mark incoming packets on a network with the netId of the network.
425 // This is so that the kernel can:
426 // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, ping
427 // replies, SYN-ACKs, etc).
428 // + Mark sockets that accept connections from this interface so that the connection stays on the
430 WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface,
431 Permission permission, bool add) {
434 fwmark.netId = netId;
435 fwmark.explicitlySelected = true;
436 fwmark.protectedFromVpn = true;
437 fwmark.permission = permission;
439 char markString[UINT32_HEX_STRLEN];
440 snprintf(markString, sizeof(markString), "0x%x", fwmark.intValue);
442 if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j",
443 "MARK", "--set-mark", markString, NULL)) {
444 ALOGE("failed to change iptables rule that sets incoming packet mark");
451 // A rule to route responses to the local network forwarded via the VPN.
453 // When a VPN is in effect, packets from the local network to upstream networks are forwarded into
454 // the VPN's tunnel interface. When the VPN forwards the responses, they emerge out of the tunnel.
455 WARN_UNUSED_RESULT int modifyVpnOutputToLocalRule(const char* vpnInterface, bool add) {
456 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL,
457 ROUTE_TABLE_LOCAL_NETWORK, MARK_UNSET, MARK_UNSET, vpnInterface, OIF_NONE,
458 INVALID_UID, INVALID_UID);
461 // A rule to route all traffic from a given set of UIDs to go over the VPN.
463 // Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket may
464 // have, if they are subject to this VPN, their traffic has to go through it. Allows the traffic to
465 // bypass the VPN if the protectedFromVpn bit is set.
466 WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd,
467 bool secure, bool add) {
471 fwmark.protectedFromVpn = false;
472 mask.protectedFromVpn = true;
477 priority = RULE_PRIORITY_SECURE_VPN;
479 priority = RULE_PRIORITY_BYPASSABLE_VPN;
481 fwmark.explicitlySelected = false;
482 mask.explicitlySelected = true;
485 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
486 mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd);
489 // A rule to allow system apps to send traffic over this VPN even if they are not part of the target
492 // This is needed for DnsProxyListener to correctly resolve a request for a user who is in the
493 // target set, but where the DnsProxyListener itself is not.
494 WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool secure,
499 fwmark.netId = netId;
500 mask.netId = FWMARK_NET_ID_MASK;
502 fwmark.permission = PERMISSION_SYSTEM;
503 mask.permission = PERMISSION_SYSTEM;
505 uint32_t priority = secure ? RULE_PRIORITY_SECURE_VPN : RULE_PRIORITY_BYPASSABLE_VPN;
507 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
511 // A rule to route traffic based on an explicitly chosen network.
513 // Supports apps that use the multinetwork APIs to restrict their traffic to a network.
515 // Even though we check permissions at the time we set a netId into the fwmark of a socket, we need
516 // to check it again in the rules here, because a network's permissions may have been updated via
517 // modifyNetworkPermission().
518 WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table,
519 Permission permission, uid_t uidStart,
520 uid_t uidEnd, bool add) {
524 fwmark.netId = netId;
525 mask.netId = FWMARK_NET_ID_MASK;
527 fwmark.explicitlySelected = true;
528 mask.explicitlySelected = true;
530 fwmark.permission = permission;
531 mask.permission = permission;
533 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table,
534 fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd);
537 // A rule to route traffic based on a chosen outgoing interface.
539 // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already knows
540 // the outgoing interface (typically for link-local communications).
541 WARN_UNUSED_RESULT int modifyOutputInterfaceRule(const char* interface, uint32_t table,
542 Permission permission, uid_t uidStart,
543 uid_t uidEnd, bool add) {
547 fwmark.permission = permission;
548 mask.permission = permission;
550 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table,
551 fwmark.intValue, mask.intValue, IIF_NONE, interface, uidStart, uidEnd);
554 // A rule to route traffic based on the chosen network.
556 // This is for sockets that have not explicitly requested a particular network, but have been
557 // bound to one when they called connect(). This ensures that sockets connected on a particular
558 // network stay on that network even if the default network changes.
559 WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table,
560 Permission permission, bool add) {
564 fwmark.netId = netId;
565 mask.netId = FWMARK_NET_ID_MASK;
567 fwmark.explicitlySelected = false;
568 mask.explicitlySelected = true;
570 fwmark.permission = permission;
571 mask.permission = permission;
573 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table,
574 fwmark.intValue, mask.intValue);
577 // A rule to enable split tunnel VPNs.
579 // If a packet with a VPN's netId doesn't find a route in the VPN's routing table, it's allowed to
580 // go over the default network, provided it wasn't explicitly restricted to the VPN and has the
581 // permissions required by the default network.
582 WARN_UNUSED_RESULT int modifyVpnFallthroughRule(uint16_t action, unsigned vpnNetId,
583 const char* physicalInterface,
584 Permission permission) {
585 uint32_t table = getRouteTableForInterface(physicalInterface);
586 if (table == RT_TABLE_UNSPEC) {
593 fwmark.netId = vpnNetId;
594 mask.netId = FWMARK_NET_ID_MASK;
596 fwmark.explicitlySelected = false;
597 mask.explicitlySelected = true;
599 fwmark.permission = permission;
600 mask.permission = permission;
602 return modifyIpRule(action, RULE_PRIORITY_VPN_FALLTHROUGH, table, fwmark.intValue,
606 // Add rules to allow legacy routes added through the requestRouteToHost() API.
607 WARN_UNUSED_RESULT int addLegacyRouteRules() {
611 fwmark.explicitlySelected = false;
612 mask.explicitlySelected = true;
614 // Rules to allow legacy routes to override the default network.
615 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
616 fwmark.intValue, mask.intValue)) {
619 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK,
620 ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, mask.intValue)) {
624 fwmark.permission = PERMISSION_SYSTEM;
625 mask.permission = PERMISSION_SYSTEM;
627 // A rule to allow legacy routes from system apps to override VPNs.
628 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDE_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
629 fwmark.intValue, mask.intValue);
632 // Add rules to lookup the local network when specified explicitly or otherwise.
633 WARN_UNUSED_RESULT int addLocalNetworkRules(unsigned localNetId) {
634 if (int ret = modifyExplicitNetworkRule(localNetId, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
635 INVALID_UID, INVALID_UID, ACTION_ADD)) {
642 fwmark.explicitlySelected = false;
643 mask.explicitlySelected = true;
645 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LOCAL_NETWORK, ROUTE_TABLE_LOCAL_NETWORK,
646 fwmark.intValue, mask.intValue);
649 // Add a new rule to look up the 'main' table, with the same selectors as the "default network"
650 // rule, but with a lower priority. We will never create routes in the main table; it should only be
651 // used for directly-connected routes implicitly created by the kernel when adding IP addresses.
652 // This is necessary, for example, when adding a route through a directly-connected gateway: in
653 // order to add the route, there must already be a directly-connected route that covers the gateway.
654 WARN_UNUSED_RESULT int addDirectlyConnectedRule() {
658 fwmark.netId = NETID_UNSET;
659 mask.netId = FWMARK_NET_ID_MASK;
661 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_DIRECTLY_CONNECTED, RT_TABLE_MAIN,
662 fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, UID_ROOT, UID_ROOT);
665 // Add an explicit unreachable rule close to the end of the prioriy list to make it clear that
666 // relying on the kernel-default "from all lookup main" rule at priority 32766 is not intended
667 // behaviour. We do flush the kernel-default rules at startup, but having an explicit unreachable
668 // rule will hopefully make things even clearer.
669 WARN_UNUSED_RESULT int addUnreachableRule() {
670 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, RT_TABLE_UNSPEC, MARK_UNSET,
674 WARN_UNUSED_RESULT int modifyLocalNetwork(unsigned netId, const char* interface, bool add) {
675 if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
678 return modifyOutputInterfaceRule(interface, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
679 INVALID_UID, INVALID_UID, add);
682 WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface,
683 Permission permission, bool add) {
684 uint32_t table = getRouteTableForInterface(interface);
685 if (table == RT_TABLE_UNSPEC) {
689 if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) {
692 if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID,
696 if (int ret = modifyOutputInterfaceRule(interface, table, permission, INVALID_UID, INVALID_UID,
700 return modifyImplicitNetworkRule(netId, table, permission, add);
703 WARN_UNUSED_RESULT int modifyVirtualNetwork(unsigned netId, const char* interface,
704 const UidRanges& uidRanges, bool secure, bool add,
705 bool modifyNonUidBasedRules) {
706 uint32_t table = getRouteTableForInterface(interface);
707 if (table == RT_TABLE_UNSPEC) {
711 for (const UidRanges::Range& range : uidRanges.getRanges()) {
712 if (int ret = modifyVpnUidRangeRule(table, range.first, range.second, secure, add)) {
715 if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.first,
716 range.second, add)) {
719 if (int ret = modifyOutputInterfaceRule(interface, table, PERMISSION_NONE, range.first,
720 range.second, add)) {
725 if (modifyNonUidBasedRules) {
726 if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
729 if (int ret = modifyVpnOutputToLocalRule(interface, add)) {
732 if (int ret = modifyVpnSystemPermissionRule(netId, table, secure, add)) {
735 return modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, add);
741 WARN_UNUSED_RESULT int modifyDefaultNetwork(uint16_t action, const char* interface,
742 Permission permission) {
743 uint32_t table = getRouteTableForInterface(interface);
744 if (table == RT_TABLE_UNSPEC) {
751 fwmark.netId = NETID_UNSET;
752 mask.netId = FWMARK_NET_ID_MASK;
754 fwmark.permission = permission;
755 mask.permission = permission;
757 return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue,
761 WARN_UNUSED_RESULT int modifyTetheredNetwork(uint16_t action, const char* inputInterface,
762 const char* outputInterface) {
763 uint32_t table = getRouteTableForInterface(outputInterface);
764 if (table == RT_TABLE_UNSPEC) {
768 return modifyIpRule(action, RULE_PRIORITY_TETHERING, table, MARK_UNSET, MARK_UNSET,
769 inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
772 // Returns 0 on success or negative errno on failure.
773 WARN_UNUSED_RESULT int flushRules() {
774 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
775 const char* argv[] = {
781 if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) {
782 ALOGE("failed to flush rules");
789 // Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected
790 // route, to the main table as well.
791 // Returns 0 on success or negative errno on failure.
792 WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination,
793 const char* nexthop, RouteController::TableType tableType) {
796 case RouteController::INTERFACE: {
797 table = getRouteTableForInterface(interface);
798 if (table == RT_TABLE_UNSPEC) {
803 case RouteController::LOCAL_NETWORK: {
804 table = ROUTE_TABLE_LOCAL_NETWORK;
807 case RouteController::LEGACY_NETWORK: {
808 table = ROUTE_TABLE_LEGACY_NETWORK;
811 case RouteController::LEGACY_SYSTEM: {
812 table = ROUTE_TABLE_LEGACY_SYSTEM;
817 int ret = modifyIpRoute(action, table, interface, destination, nexthop);
818 // We allow apps to call requestRouteToHost() multiple times with the same route, so ignore
819 // EEXIST failures when adding routes to legacy tables.
820 if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST &&
821 (tableType == RouteController::LEGACY_NETWORK ||
822 tableType == RouteController::LEGACY_SYSTEM))) {
829 // Returns 0 on success or negative errno on failure.
830 WARN_UNUSED_RESULT int flushRoutes(const char* interface) {
831 uint32_t table = getRouteTableForInterface(interface);
832 if (table == RT_TABLE_UNSPEC) {
836 char tableString[UINT32_STRLEN];
837 snprintf(tableString, sizeof(tableString), "%u", table);
840 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
841 const char* argv[] = {
850 // A flush works by dumping routes and deleting each route as it's returned, and it can
851 // fail if something else deletes the route between the dump and the delete. This can
852 // happen, for example, if an interface goes down while we're trying to flush its routes.
853 // So try multiple times and only return an error if the last attempt fails.
855 // TODO: replace this with our own netlink code.
856 unsigned attempts = 0;
859 err = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv),
862 } while (err != 0 && attempts < ROUTE_FLUSH_ATTEMPTS);
864 ALOGE("failed to flush %s routes in table %s after %d attempts",
865 IP_VERSIONS[i], tableString, attempts);
870 // If we failed to flush routes, the caller may elect to keep this interface around, so keep
871 // track of its name.
873 interfaceToTable.erase(interface);
881 int RouteController::Init(unsigned localNetId) {
882 if (int ret = flushRules()) {
885 if (int ret = addLegacyRouteRules()) {
888 if (int ret = addLocalNetworkRules(localNetId)) {
891 if (int ret = addDirectlyConnectedRule()) {
894 if (int ret = addUnreachableRule()) {
897 updateTableNamesFile();
901 int RouteController::addInterfaceToLocalNetwork(unsigned netId, const char* interface) {
902 return modifyLocalNetwork(netId, interface, ACTION_ADD);
905 int RouteController::removeInterfaceFromLocalNetwork(unsigned netId, const char* interface) {
906 return modifyLocalNetwork(netId, interface, ACTION_DEL);
909 int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface,
910 Permission permission) {
911 if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) {
914 updateTableNamesFile();
918 int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface,
919 Permission permission) {
920 if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) {
923 if (int ret = flushRoutes(interface)) {
926 updateTableNamesFile();
930 int RouteController::addInterfaceToVirtualNetwork(unsigned netId, const char* interface,
931 bool secure, const UidRanges& uidRanges) {
932 if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
933 MODIFY_NON_UID_BASED_RULES)) {
936 updateTableNamesFile();
940 int RouteController::removeInterfaceFromVirtualNetwork(unsigned netId, const char* interface,
941 bool secure, const UidRanges& uidRanges) {
942 if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
943 MODIFY_NON_UID_BASED_RULES)) {
946 if (int ret = flushRoutes(interface)) {
949 updateTableNamesFile();
953 int RouteController::modifyPhysicalNetworkPermission(unsigned netId, const char* interface,
954 Permission oldPermission,
955 Permission newPermission) {
956 // Add the new rules before deleting the old ones, to avoid race conditions.
957 if (int ret = modifyPhysicalNetwork(netId, interface, newPermission, ACTION_ADD)) {
960 return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL);
963 int RouteController::addUsersToVirtualNetwork(unsigned netId, const char* interface, bool secure,
964 const UidRanges& uidRanges) {
965 return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
966 !MODIFY_NON_UID_BASED_RULES);
969 int RouteController::removeUsersFromVirtualNetwork(unsigned netId, const char* interface,
970 bool secure, const UidRanges& uidRanges) {
971 return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
972 !MODIFY_NON_UID_BASED_RULES);
975 int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) {
976 return modifyDefaultNetwork(RTM_NEWRULE, interface, permission);
979 int RouteController::removeInterfaceFromDefaultNetwork(const char* interface,
980 Permission permission) {
981 return modifyDefaultNetwork(RTM_DELRULE, interface, permission);
984 int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop,
985 TableType tableType) {
986 return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType);
989 int RouteController::removeRoute(const char* interface, const char* destination,
990 const char* nexthop, TableType tableType) {
991 return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType);
994 int RouteController::enableTethering(const char* inputInterface, const char* outputInterface) {
995 return modifyTetheredNetwork(RTM_NEWRULE, inputInterface, outputInterface);
998 int RouteController::disableTethering(const char* inputInterface, const char* outputInterface) {
999 return modifyTetheredNetwork(RTM_DELRULE, inputInterface, outputInterface);
1002 int RouteController::addVirtualNetworkFallthrough(unsigned vpnNetId, const char* physicalInterface,
1003 Permission permission) {
1004 return modifyVpnFallthroughRule(RTM_NEWRULE, vpnNetId, physicalInterface, permission);
1007 int RouteController::removeVirtualNetworkFallthrough(unsigned vpnNetId,
1008 const char* physicalInterface,
1009 Permission permission) {
1010 return modifyVpnFallthroughRule(RTM_DELRULE, vpnNetId, physicalInterface, permission);