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>
26 #include <private/android_filesystem_config.h>
31 #include "UidRanges.h"
32 #include "DummyNetwork.h"
34 #include "android-base/file.h"
35 #define LOG_TAG "Netd"
37 #include "logwrap/logwrap.h"
38 #include "netutils/ifc.h"
39 #include "resolv_netid.h"
41 using android::base::WriteStringToFile;
45 // BEGIN CONSTANTS --------------------------------------------------------------------------------
47 const uint32_t RULE_PRIORITY_VPN_OVERRIDE_SYSTEM = 10000;
48 const uint32_t RULE_PRIORITY_VPN_OVERRIDE_OIF = 10500;
49 const uint32_t RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000;
50 const uint32_t RULE_PRIORITY_SECURE_VPN = 12000;
51 const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK = 13000;
52 const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE = 14000;
53 const uint32_t RULE_PRIORITY_LEGACY_SYSTEM = 15000;
54 const uint32_t RULE_PRIORITY_LEGACY_NETWORK = 16000;
55 const uint32_t RULE_PRIORITY_LOCAL_NETWORK = 17000;
56 const uint32_t RULE_PRIORITY_TETHERING = 18000;
57 const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK = 19000;
58 const uint32_t RULE_PRIORITY_BYPASSABLE_VPN = 20000;
59 const uint32_t RULE_PRIORITY_VPN_FALLTHROUGH = 21000;
60 const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 22000;
61 const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED = 23000;
62 const uint32_t RULE_PRIORITY_UNREACHABLE = 32000;
64 const uint32_t ROUTE_TABLE_LOCAL_NETWORK = 97;
65 const uint32_t ROUTE_TABLE_LEGACY_NETWORK = 98;
66 const uint32_t ROUTE_TABLE_LEGACY_SYSTEM = 99;
68 const char* const ROUTE_TABLE_NAME_LOCAL_NETWORK = "local_network";
69 const char* const ROUTE_TABLE_NAME_LEGACY_NETWORK = "legacy_network";
70 const char* const ROUTE_TABLE_NAME_LEGACY_SYSTEM = "legacy_system";
72 const char* const ROUTE_TABLE_NAME_LOCAL = "local";
73 const char* const ROUTE_TABLE_NAME_MAIN = "main";
75 // TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not
76 // upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make
77 // it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert
78 // that will warn us if upstream has given these values some other meaning.
79 const uint16_t FRA_UID_START = 18;
80 const uint16_t FRA_UID_END = 19;
81 static_assert(FRA_UID_START > FRA_MAX,
82 "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. "
83 "Check that these values match what the kernel does and then update this assertion.");
85 const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK;
86 const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL;
88 const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0};
90 const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6};
92 const char* const IP_VERSIONS[] = {"-4", "-6"};
94 const uid_t UID_ROOT = 0;
95 const char* const IIF_LOOPBACK = "lo";
96 const char* const IIF_NONE = NULL;
97 const char* const OIF_NONE = NULL;
98 const bool ACTION_ADD = true;
99 const bool ACTION_DEL = false;
100 const bool MODIFY_NON_UID_BASED_RULES = true;
102 const char* const RT_TABLES_PATH = "/data/misc/net/rt_tables";
103 const mode_t RT_TABLES_MODE = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; // mode 0644, rw-r--r--
105 const unsigned ROUTE_FLUSH_ATTEMPTS = 2;
107 // Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'"
108 // warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t).
109 constexpr uint16_t U16_RTA_LENGTH(uint16_t x) {
110 return RTA_LENGTH(x);
113 // These are practically const, but can't be declared so, because they are used to initialize
114 // non-const pointers ("void* iov_base") in iovec arrays.
115 rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY };
116 rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE };
117 rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK };
118 rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK };
119 rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START };
120 rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END };
122 rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE };
123 rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF };
125 uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0};
127 // END CONSTANTS ----------------------------------------------------------------------------------
129 // No locks needed because RouteController is accessed only from one thread (in CommandListener).
130 std::map<std::string, uint32_t> interfaceToTable;
132 uint32_t getRouteTableForInterface(const char* interface) {
133 uint32_t index = if_nametoindex(interface);
135 index += RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX;
136 interfaceToTable[interface] = index;
139 // If the interface goes away if_nametoindex() will return 0 but we still need to know
140 // the index so we can remove the rules and routes.
141 auto iter = interfaceToTable.find(interface);
142 if (iter == interfaceToTable.end()) {
143 ALOGE("cannot find interface %s", interface);
144 return RT_TABLE_UNSPEC;
149 void addTableName(uint32_t table, const std::string& name, std::string* contents) {
150 char tableString[UINT32_STRLEN];
151 snprintf(tableString, sizeof(tableString), "%u", table);
152 *contents += tableString;
158 // Doesn't return success/failure as the file is optional; it's okay if we fail to update it.
159 void updateTableNamesFile() {
160 std::string contents;
162 addTableName(RT_TABLE_LOCAL, ROUTE_TABLE_NAME_LOCAL, &contents);
163 addTableName(RT_TABLE_MAIN, ROUTE_TABLE_NAME_MAIN, &contents);
165 addTableName(ROUTE_TABLE_LOCAL_NETWORK, ROUTE_TABLE_NAME_LOCAL_NETWORK, &contents);
166 addTableName(ROUTE_TABLE_LEGACY_NETWORK, ROUTE_TABLE_NAME_LEGACY_NETWORK, &contents);
167 addTableName(ROUTE_TABLE_LEGACY_SYSTEM, ROUTE_TABLE_NAME_LEGACY_SYSTEM, &contents);
169 for (const auto& entry : interfaceToTable) {
170 addTableName(entry.second, entry.first, &contents);
173 if (!WriteStringToFile(contents, RT_TABLES_PATH, RT_TABLES_MODE, AID_SYSTEM, AID_WIFI)) {
174 ALOGE("failed to write to %s (%s)", RT_TABLES_PATH, strerror(errno));
179 // Sends a netlink request and expects an ack.
180 // |iov| is an array of struct iovec that contains the netlink message payload.
181 // The netlink header is generated by this function based on |action| and |flags|.
182 // Returns -errno if there was an error or if the kernel reported an error.
183 WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) {
185 .nlmsg_type = action,
186 .nlmsg_flags = flags,
188 iov[0].iov_base = &nlmsg;
189 iov[0].iov_len = sizeof(nlmsg);
190 for (int i = 0; i < iovlen; ++i) {
191 nlmsg.nlmsg_len += iov[i].iov_len;
200 int sock = socket(AF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_ROUTE);
202 connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS),
203 sizeof(NETLINK_ADDRESS)) != -1 &&
204 writev(sock, iov, iovlen) != -1 &&
205 (ret = recv(sock, &response, sizeof(response), 0)) != -1) {
206 if (ret == sizeof(response)) {
207 ret = response.err.error; // Netlink errors are negative errno.
209 ALOGE("netlink response contains error (%s)", strerror(-ret));
212 ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response));
216 ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno));
227 // Returns 0 on success or negative errno on failure.
228 int padInterfaceName(const char* input, char* name, size_t* length, uint16_t* padding) {
234 *length = strlcpy(name, input, IFNAMSIZ) + 1;
235 if (*length > IFNAMSIZ) {
236 ALOGE("interface name too long (%zu > %u)", *length, IFNAMSIZ);
237 return -ENAMETOOLONG;
239 *padding = RTA_SPACE(*length) - RTA_LENGTH(*length);
243 // Adds or removes a routing rule for IPv4 and IPv6.
245 // + If |priority| is RULE_PRIORITY_UNREACHABLE, the rule returns ENETUNREACH (i.e., specifies an
246 // action of FR_ACT_UNREACHABLE). Otherwise, the rule specifies an action of FR_ACT_TO_TBL.
247 // + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the table is
248 // unspecified. An unspecified table is only allowed when deleting a rule.
249 // + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is
251 // + If |iif| is non-NULL, the rule matches the specified incoming interface.
252 // + If |oif| is non-NULL, the rule matches the specified outgoing interface.
253 // + If |uidStart| and |uidEnd| are not INVALID_UID, the rule matches packets from UIDs in that
254 // range (inclusive). Otherwise, the rule matches packets from all UIDs.
256 // Returns 0 on success or negative errno on failure.
257 WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
258 uint32_t fwmark, uint32_t mask, const char* iif,
259 const char* oif, uid_t uidStart, uid_t uidEnd) {
260 // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask.
261 if (fwmark & ~mask) {
262 ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark);
266 // Interface names must include exactly one terminating NULL and be properly padded, or older
267 // kernels will refuse to delete rules.
268 char iifName[IFNAMSIZ], oifName[IFNAMSIZ];
269 size_t iifLength, oifLength;
270 uint16_t iifPadding, oifPadding;
271 if (int ret = padInterfaceName(iif, iifName, &iifLength, &iifPadding)) {
274 if (int ret = padInterfaceName(oif, oifName, &oifLength, &oifPadding)) {
278 // Either both start and end UID must be specified, or neither.
279 if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) {
280 ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd);
283 bool isUidRule = (uidStart != INVALID_UID);
285 // Assemble a rule request and put it in an array of iovec structures.
286 fib_rule_hdr rule = {
287 .action = static_cast<uint8_t>(priority != RULE_PRIORITY_UNREACHABLE ? FR_ACT_TO_TBL :
289 // Note that here we're implicitly setting rule.table to 0. When we want to specify a
290 // non-zero table, we do this via the FRATTR_TABLE attribute.
293 // Don't ever create a rule that looks up table 0, because table 0 is the local table.
294 // It's OK to specify a table ID of 0 when deleting a rule, because that doesn't actually select
295 // table 0, it's a wildcard that matches anything.
296 if (table == RT_TABLE_UNSPEC && rule.action == FR_ACT_TO_TBL && action != RTM_DELRULE) {
297 ALOGE("RT_TABLE_UNSPEC only allowed when deleting rules");
301 rtattr fraIifName = { U16_RTA_LENGTH(iifLength), FRA_IIFNAME };
302 rtattr fraOifName = { U16_RTA_LENGTH(oifLength), FRA_OIFNAME };
306 { &rule, sizeof(rule) },
307 { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) },
308 { &priority, sizeof(priority) },
309 { &FRATTR_TABLE, table != RT_TABLE_UNSPEC ? sizeof(FRATTR_TABLE) : 0 },
310 { &table, table != RT_TABLE_UNSPEC ? sizeof(table) : 0 },
311 { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 },
312 { &fwmark, mask ? sizeof(fwmark) : 0 },
313 { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 },
314 { &mask, mask ? sizeof(mask) : 0 },
315 { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 },
316 { &uidStart, isUidRule ? sizeof(uidStart) : 0 },
317 { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 },
318 { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 },
319 { &fraIifName, iif != IIF_NONE ? sizeof(fraIifName) : 0 },
320 { iifName, iifLength },
321 { PADDING_BUFFER, iifPadding },
322 { &fraOifName, oif != OIF_NONE ? sizeof(fraOifName) : 0 },
323 { oifName, oifLength },
324 { PADDING_BUFFER, oifPadding },
327 uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS;
328 for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) {
329 rule.family = AF_FAMILIES[i];
330 if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) {
338 WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
339 uint32_t fwmark, uint32_t mask) {
340 return modifyIpRule(action, priority, table, fwmark, mask, IIF_NONE, OIF_NONE, INVALID_UID,
344 // Adds or deletes an IPv4 or IPv6 route.
345 // Returns 0 on success or negative errno on failure.
346 WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface,
347 const char* destination, const char* nexthop) {
348 // At least the destination must be non-null.
350 ALOGE("null destination");
355 uint8_t rawAddress[sizeof(in6_addr)];
357 uint8_t prefixLength;
358 int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress),
361 ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength));
365 if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) {
366 ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress));
367 return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6.
370 uint8_t type = RTN_UNICAST;
372 uint8_t rawNexthop[sizeof(in6_addr)];
374 if (nexthop && !strcmp(nexthop, "unreachable")) {
375 type = RTN_UNREACHABLE;
376 // 'interface' is likely non-NULL, as the caller (modifyRoute()) likely used it to lookup
377 // the table number. But it's an error to specify an interface ("dev ...") or a nexthop for
378 // unreachable routes, so nuke them. (IPv6 allows them to be specified; IPv4 doesn't.)
379 interface = OIF_NONE;
381 } else if (nexthop && !strcmp(nexthop, "throw")) {
383 interface = OIF_NONE;
386 // If an interface was specified, find the ifindex.
387 if (interface != OIF_NONE) {
388 ifindex = if_nametoindex(interface);
390 ALOGE("cannot find interface %s", interface);
395 // If a nexthop was specified, parse it as the same family as the prefix.
396 if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) {
397 ALOGE("inet_pton failed for nexthop %s", nexthop);
402 // Assemble a rtmsg and put it in an array of iovec structures.
404 .rtm_protocol = RTPROT_STATIC,
406 .rtm_family = family,
407 .rtm_dst_len = prefixLength,
408 .rtm_scope = static_cast<uint8_t>(nexthop ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK),
411 rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST };
412 rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY };
416 { &route, sizeof(route) },
417 { &RTATTR_TABLE, sizeof(RTATTR_TABLE) },
418 { &table, sizeof(table) },
419 { &rtaDst, sizeof(rtaDst) },
420 { rawAddress, static_cast<size_t>(rawLength) },
421 { &RTATTR_OIF, interface != OIF_NONE ? sizeof(RTATTR_OIF) : 0 },
422 { &ifindex, interface != OIF_NONE ? sizeof(ifindex) : 0 },
423 { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 },
424 { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 },
427 uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS :
428 NETLINK_REQUEST_FLAGS;
429 return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov));
432 // An iptables rule to mark incoming packets on a network with the netId of the network.
434 // This is so that the kernel can:
435 // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, ping
436 // replies, SYN-ACKs, etc).
437 // + Mark sockets that accept connections from this interface so that the connection stays on the
439 WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface,
440 Permission permission, bool add) {
443 fwmark.netId = netId;
444 fwmark.explicitlySelected = true;
445 fwmark.protectedFromVpn = true;
446 fwmark.permission = permission;
448 char markString[UINT32_HEX_STRLEN];
449 snprintf(markString, sizeof(markString), "0x%x", fwmark.intValue);
451 if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j",
452 "MARK", "--set-mark", markString, NULL)) {
453 ALOGE("failed to change iptables rule that sets incoming packet mark");
460 // A rule to route responses to the local network forwarded via the VPN.
462 // When a VPN is in effect, packets from the local network to upstream networks are forwarded into
463 // the VPN's tunnel interface. When the VPN forwards the responses, they emerge out of the tunnel.
464 WARN_UNUSED_RESULT int modifyVpnOutputToLocalRule(const char* vpnInterface, bool add) {
465 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL,
466 ROUTE_TABLE_LOCAL_NETWORK, MARK_UNSET, MARK_UNSET, vpnInterface, OIF_NONE,
467 INVALID_UID, INVALID_UID);
470 // A rule to route all traffic from a given set of UIDs to go over the VPN.
472 // Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket may
473 // have, if they are subject to this VPN, their traffic has to go through it. Allows the traffic to
474 // bypass the VPN if the protectedFromVpn bit is set.
475 WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd,
476 bool secure, bool add) {
480 fwmark.protectedFromVpn = false;
481 mask.protectedFromVpn = true;
486 priority = RULE_PRIORITY_SECURE_VPN;
488 priority = RULE_PRIORITY_BYPASSABLE_VPN;
490 fwmark.explicitlySelected = false;
491 mask.explicitlySelected = true;
494 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
495 mask.intValue, IIF_LOOPBACK, OIF_NONE, uidStart, uidEnd);
498 // A rule to allow system apps to send traffic over this VPN even if they are not part of the target
501 // This is needed for DnsProxyListener to correctly resolve a request for a user who is in the
502 // target set, but where the DnsProxyListener itself is not.
503 WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool secure,
508 fwmark.netId = netId;
509 mask.netId = FWMARK_NET_ID_MASK;
511 fwmark.permission = PERMISSION_SYSTEM;
512 mask.permission = PERMISSION_SYSTEM;
514 uint32_t priority = secure ? RULE_PRIORITY_SECURE_VPN : RULE_PRIORITY_BYPASSABLE_VPN;
516 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
520 // A rule to route traffic based on an explicitly chosen network.
522 // Supports apps that use the multinetwork APIs to restrict their traffic to a network.
524 // Even though we check permissions at the time we set a netId into the fwmark of a socket, we need
525 // to check it again in the rules here, because a network's permissions may have been updated via
526 // modifyNetworkPermission().
527 WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table,
528 Permission permission, uid_t uidStart,
529 uid_t uidEnd, bool add) {
533 fwmark.netId = netId;
534 mask.netId = FWMARK_NET_ID_MASK;
536 fwmark.explicitlySelected = true;
537 mask.explicitlySelected = true;
539 fwmark.permission = permission;
540 mask.permission = permission;
542 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table,
543 fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd);
546 // A rule to route traffic based on a chosen outgoing interface.
548 // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already knows
549 // the outgoing interface (typically for link-local communications).
550 WARN_UNUSED_RESULT int modifyOutputInterfaceRules(const char* interface, uint32_t table,
551 Permission permission, uid_t uidStart,
552 uid_t uidEnd, bool add) {
556 fwmark.permission = permission;
557 mask.permission = permission;
559 // If this rule does not specify a UID range, then also add a corresponding high-priority rule
560 // for UID. This covers forwarded packets and system daemons such as the tethering DHCP server.
561 if (uidStart == INVALID_UID && uidEnd == INVALID_UID) {
562 if (int ret = modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_VPN_OVERRIDE_OIF,
563 table, fwmark.intValue, mask.intValue, IIF_NONE, interface,
564 UID_ROOT, UID_ROOT)) {
569 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table,
570 fwmark.intValue, mask.intValue, IIF_NONE, interface, uidStart, uidEnd);
573 // A rule to route traffic based on the chosen network.
575 // This is for sockets that have not explicitly requested a particular network, but have been
576 // bound to one when they called connect(). This ensures that sockets connected on a particular
577 // network stay on that network even if the default network changes.
578 WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table,
579 Permission permission, bool add) {
583 fwmark.netId = netId;
584 mask.netId = FWMARK_NET_ID_MASK;
586 fwmark.explicitlySelected = false;
587 mask.explicitlySelected = true;
589 fwmark.permission = permission;
590 mask.permission = permission;
592 return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table,
593 fwmark.intValue, mask.intValue);
596 // A rule to enable split tunnel VPNs.
598 // If a packet with a VPN's netId doesn't find a route in the VPN's routing table, it's allowed to
599 // go over the default network, provided it wasn't explicitly restricted to the VPN and has the
600 // permissions required by the default network.
601 WARN_UNUSED_RESULT int modifyVpnFallthroughRule(uint16_t action, unsigned vpnNetId,
602 const char* physicalInterface,
603 Permission permission) {
604 uint32_t table = getRouteTableForInterface(physicalInterface);
605 if (table == RT_TABLE_UNSPEC) {
612 fwmark.netId = vpnNetId;
613 mask.netId = FWMARK_NET_ID_MASK;
615 fwmark.explicitlySelected = false;
616 mask.explicitlySelected = true;
618 fwmark.permission = permission;
619 mask.permission = permission;
621 return modifyIpRule(action, RULE_PRIORITY_VPN_FALLTHROUGH, table, fwmark.intValue,
625 // Add rules to allow legacy routes added through the requestRouteToHost() API.
626 WARN_UNUSED_RESULT int addLegacyRouteRules() {
630 fwmark.explicitlySelected = false;
631 mask.explicitlySelected = true;
633 // Rules to allow legacy routes to override the default network.
634 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
635 fwmark.intValue, mask.intValue)) {
638 if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK,
639 ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, mask.intValue)) {
643 fwmark.permission = PERMISSION_SYSTEM;
644 mask.permission = PERMISSION_SYSTEM;
646 // A rule to allow legacy routes from system apps to override VPNs.
647 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDE_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
648 fwmark.intValue, mask.intValue);
651 // Add rules to lookup the local network when specified explicitly or otherwise.
652 WARN_UNUSED_RESULT int addLocalNetworkRules(unsigned localNetId) {
653 if (int ret = modifyExplicitNetworkRule(localNetId, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
654 INVALID_UID, INVALID_UID, ACTION_ADD)) {
661 fwmark.explicitlySelected = false;
662 mask.explicitlySelected = true;
664 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LOCAL_NETWORK, ROUTE_TABLE_LOCAL_NETWORK,
665 fwmark.intValue, mask.intValue);
668 int configureDummyNetwork() {
669 const char *interface = DummyNetwork::INTERFACE_NAME;
670 uint32_t table = getRouteTableForInterface(interface);
671 if (table == RT_TABLE_UNSPEC) {
672 // getRouteTableForInterface has already looged an error.
677 int ret = ifc_up(interface);
680 ALOGE("Can't bring up %s: %s", interface, strerror(errno));
684 if ((ret = modifyOutputInterfaceRules(interface, table, PERMISSION_NONE,
685 INVALID_UID, INVALID_UID, ACTION_ADD))) {
686 ALOGE("Can't create oif rules for %s: %s", interface, strerror(-ret));
690 if ((ret = modifyIpRoute(RTM_NEWROUTE, table, interface, "0.0.0.0/0", NULL))) {
691 ALOGE("Can't add IPv4 default route to %s: %s", interface, strerror(-ret));
695 if ((ret = modifyIpRoute(RTM_NEWROUTE, table, interface, "::/0", NULL))) {
696 ALOGE("Can't add IPv6 default route to %s: %s", interface, strerror(-ret));
703 // Add a new rule to look up the 'main' table, with the same selectors as the "default network"
704 // rule, but with a lower priority. We will never create routes in the main table; it should only be
705 // used for directly-connected routes implicitly created by the kernel when adding IP addresses.
706 // This is necessary, for example, when adding a route through a directly-connected gateway: in
707 // order to add the route, there must already be a directly-connected route that covers the gateway.
708 WARN_UNUSED_RESULT int addDirectlyConnectedRule() {
712 fwmark.netId = NETID_UNSET;
713 mask.netId = FWMARK_NET_ID_MASK;
715 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_DIRECTLY_CONNECTED, RT_TABLE_MAIN,
716 fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, UID_ROOT, UID_ROOT);
719 // Add an explicit unreachable rule close to the end of the prioriy list to make it clear that
720 // relying on the kernel-default "from all lookup main" rule at priority 32766 is not intended
721 // behaviour. We do flush the kernel-default rules at startup, but having an explicit unreachable
722 // rule will hopefully make things even clearer.
723 WARN_UNUSED_RESULT int addUnreachableRule() {
724 return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, RT_TABLE_UNSPEC, MARK_UNSET,
728 WARN_UNUSED_RESULT int modifyLocalNetwork(unsigned netId, const char* interface, bool add) {
729 if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
732 return modifyOutputInterfaceRules(interface, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
733 INVALID_UID, INVALID_UID, add);
736 WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface,
737 Permission permission, bool add) {
738 uint32_t table = getRouteTableForInterface(interface);
739 if (table == RT_TABLE_UNSPEC) {
743 if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) {
746 if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID,
750 if (int ret = modifyOutputInterfaceRules(interface, table, permission, INVALID_UID, INVALID_UID,
754 return modifyImplicitNetworkRule(netId, table, permission, add);
757 WARN_UNUSED_RESULT int modifyVirtualNetwork(unsigned netId, const char* interface,
758 const UidRanges& uidRanges, bool secure, bool add,
759 bool modifyNonUidBasedRules) {
760 uint32_t table = getRouteTableForInterface(interface);
761 if (table == RT_TABLE_UNSPEC) {
765 for (const UidRanges::Range& range : uidRanges.getRanges()) {
766 if (int ret = modifyVpnUidRangeRule(table, range.first, range.second, secure, add)) {
769 if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.first,
770 range.second, add)) {
773 if (int ret = modifyOutputInterfaceRules(interface, table, PERMISSION_NONE, range.first,
774 range.second, add)) {
779 if (modifyNonUidBasedRules) {
780 if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
783 if (int ret = modifyVpnOutputToLocalRule(interface, add)) {
786 if (int ret = modifyVpnSystemPermissionRule(netId, table, secure, add)) {
789 return modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, add);
795 WARN_UNUSED_RESULT int modifyDefaultNetwork(uint16_t action, const char* interface,
796 Permission permission) {
797 uint32_t table = getRouteTableForInterface(interface);
798 if (table == RT_TABLE_UNSPEC) {
805 fwmark.netId = NETID_UNSET;
806 mask.netId = FWMARK_NET_ID_MASK;
808 fwmark.permission = permission;
809 mask.permission = permission;
811 return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue,
815 WARN_UNUSED_RESULT int modifyTetheredNetwork(uint16_t action, const char* inputInterface,
816 const char* outputInterface) {
817 uint32_t table = getRouteTableForInterface(outputInterface);
818 if (table == RT_TABLE_UNSPEC) {
822 return modifyIpRule(action, RULE_PRIORITY_TETHERING, table, MARK_UNSET, MARK_UNSET,
823 inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
826 // Returns 0 on success or negative errno on failure.
827 WARN_UNUSED_RESULT int flushRules() {
828 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
829 const char* argv[] = {
835 if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) {
836 ALOGE("failed to flush rules");
843 // Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected
844 // route, to the main table as well.
845 // Returns 0 on success or negative errno on failure.
846 WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination,
847 const char* nexthop, RouteController::TableType tableType) {
850 case RouteController::INTERFACE: {
851 table = getRouteTableForInterface(interface);
852 if (table == RT_TABLE_UNSPEC) {
857 case RouteController::LOCAL_NETWORK: {
858 table = ROUTE_TABLE_LOCAL_NETWORK;
861 case RouteController::LEGACY_NETWORK: {
862 table = ROUTE_TABLE_LEGACY_NETWORK;
865 case RouteController::LEGACY_SYSTEM: {
866 table = ROUTE_TABLE_LEGACY_SYSTEM;
871 int ret = modifyIpRoute(action, table, interface, destination, nexthop);
872 // Trying to add a route that already exists shouldn't cause an error.
873 if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST)) {
880 // Returns 0 on success or negative errno on failure.
881 WARN_UNUSED_RESULT int flushRoutes(const char* interface) {
882 uint32_t table = getRouteTableForInterface(interface);
883 if (table == RT_TABLE_UNSPEC) {
887 char tableString[UINT32_STRLEN];
888 snprintf(tableString, sizeof(tableString), "%u", table);
891 for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
892 const char* argv[] = {
901 // A flush works by dumping routes and deleting each route as it's returned, and it can
902 // fail if something else deletes the route between the dump and the delete. This can
903 // happen, for example, if an interface goes down while we're trying to flush its routes.
904 // So try multiple times and only return an error if the last attempt fails.
906 // TODO: replace this with our own netlink code.
907 unsigned attempts = 0;
910 err = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv),
913 } while (err != 0 && attempts < ROUTE_FLUSH_ATTEMPTS);
915 ALOGE("failed to flush %s routes in table %s after %d attempts",
916 IP_VERSIONS[i], tableString, attempts);
921 // If we failed to flush routes, the caller may elect to keep this interface around, so keep
922 // track of its name.
924 interfaceToTable.erase(interface);
930 WARN_UNUSED_RESULT int clearTetheringRules(const char* inputInterface) {
933 ret = modifyIpRule(RTM_DELRULE, RULE_PRIORITY_TETHERING, 0, MARK_UNSET, MARK_UNSET,
934 inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
937 if (ret == -ENOENT) {
946 int RouteController::Init(unsigned localNetId) {
947 if (int ret = flushRules()) {
950 if (int ret = addLegacyRouteRules()) {
953 if (int ret = addLocalNetworkRules(localNetId)) {
956 if (int ret = addDirectlyConnectedRule()) {
959 if (int ret = addUnreachableRule()) {
962 // Don't complain if we can't add the dummy network, since not all devices support it.
963 configureDummyNetwork();
965 updateTableNamesFile();
969 int RouteController::addInterfaceToLocalNetwork(unsigned netId, const char* interface) {
970 return modifyLocalNetwork(netId, interface, ACTION_ADD);
973 int RouteController::removeInterfaceFromLocalNetwork(unsigned netId, const char* interface) {
974 return modifyLocalNetwork(netId, interface, ACTION_DEL);
977 int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface,
978 Permission permission) {
979 if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) {
982 updateTableNamesFile();
986 int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface,
987 Permission permission) {
988 if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) {
991 if (int ret = flushRoutes(interface)) {
994 if (int ret = clearTetheringRules(interface)) {
997 updateTableNamesFile();
1001 int RouteController::addInterfaceToVirtualNetwork(unsigned netId, const char* interface,
1002 bool secure, const UidRanges& uidRanges) {
1003 if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
1004 MODIFY_NON_UID_BASED_RULES)) {
1007 updateTableNamesFile();
1011 int RouteController::removeInterfaceFromVirtualNetwork(unsigned netId, const char* interface,
1012 bool secure, const UidRanges& uidRanges) {
1013 if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
1014 MODIFY_NON_UID_BASED_RULES)) {
1017 if (int ret = flushRoutes(interface)) {
1020 updateTableNamesFile();
1024 int RouteController::modifyPhysicalNetworkPermission(unsigned netId, const char* interface,
1025 Permission oldPermission,
1026 Permission newPermission) {
1027 // Add the new rules before deleting the old ones, to avoid race conditions.
1028 if (int ret = modifyPhysicalNetwork(netId, interface, newPermission, ACTION_ADD)) {
1031 return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL);
1034 int RouteController::addUsersToVirtualNetwork(unsigned netId, const char* interface, bool secure,
1035 const UidRanges& uidRanges) {
1036 return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
1037 !MODIFY_NON_UID_BASED_RULES);
1040 int RouteController::removeUsersFromVirtualNetwork(unsigned netId, const char* interface,
1041 bool secure, const UidRanges& uidRanges) {
1042 return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
1043 !MODIFY_NON_UID_BASED_RULES);
1046 int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) {
1047 return modifyDefaultNetwork(RTM_NEWRULE, interface, permission);
1050 int RouteController::removeInterfaceFromDefaultNetwork(const char* interface,
1051 Permission permission) {
1052 return modifyDefaultNetwork(RTM_DELRULE, interface, permission);
1055 int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop,
1056 TableType tableType) {
1057 return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType);
1060 int RouteController::removeRoute(const char* interface, const char* destination,
1061 const char* nexthop, TableType tableType) {
1062 return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType);
1065 int RouteController::enableTethering(const char* inputInterface, const char* outputInterface) {
1066 return modifyTetheredNetwork(RTM_NEWRULE, inputInterface, outputInterface);
1069 int RouteController::disableTethering(const char* inputInterface, const char* outputInterface) {
1070 return modifyTetheredNetwork(RTM_DELRULE, inputInterface, outputInterface);
1073 int RouteController::addVirtualNetworkFallthrough(unsigned vpnNetId, const char* physicalInterface,
1074 Permission permission) {
1075 return modifyVpnFallthroughRule(RTM_NEWRULE, vpnNetId, physicalInterface, permission);
1078 int RouteController::removeVirtualNetworkFallthrough(unsigned vpnNetId,
1079 const char* physicalInterface,
1080 Permission permission) {
1081 return modifyVpnFallthroughRule(RTM_DELRULE, vpnNetId, physicalInterface, permission);