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 <arpa/inet.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <linux/fib_rules.h>
23#include <net/if.h>
24#include <sys/stat.h>
25
26#include <private/android_filesystem_config.h>
27
28#include <map>
29
30#include "DummyNetwork.h"
31#include "Fwmark.h"
32#include "NetdConstants.h"
33#include "NetlinkCommands.h"
34#include "UidRanges.h"
35
36#include "android-base/file.h"
37#include <android-base/stringprintf.h>
38#define LOG_TAG "Netd"
39#include "log/log.h"
40#include "logwrap/logwrap.h"
41#include "netutils/ifc.h"
42#include "resolv_netid.h"
43
44using android::base::StringPrintf;
45using android::base::WriteStringToFile;
46using android::net::UidRange;
47
48namespace android {
49namespace net {
50
51auto RouteController::iptablesRestoreCommandFunction = execIptablesRestoreCommand;
52
53// BEGIN CONSTANTS --------------------------------------------------------------------------------
54
55const uint32_t RULE_PRIORITY_VPN_OVERRIDE_SYSTEM = 10000;
56const uint32_t RULE_PRIORITY_VPN_OVERRIDE_OIF    = 10500;
57const uint32_t RULE_PRIORITY_VPN_OUTPUT_TO_LOCAL = 11000;
58const uint32_t RULE_PRIORITY_SECURE_VPN          = 12000;
59const uint32_t RULE_PRIORITY_PROHIBIT_NON_VPN    = 12500;
60const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK    = 13000;
61const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE    = 14000;
62const uint32_t RULE_PRIORITY_LEGACY_SYSTEM       = 15000;
63const uint32_t RULE_PRIORITY_LEGACY_NETWORK      = 16000;
64const uint32_t RULE_PRIORITY_LOCAL_NETWORK       = 17000;
65const uint32_t RULE_PRIORITY_TETHERING           = 18000;
66const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK    = 19000;
67const uint32_t RULE_PRIORITY_BYPASSABLE_VPN      = 20000;
68const uint32_t RULE_PRIORITY_VPN_FALLTHROUGH     = 21000;
69const uint32_t RULE_PRIORITY_DEFAULT_NETWORK     = 22000;
70const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED  = 23000;
71const uint32_t RULE_PRIORITY_UNREACHABLE         = 32000;
72
73const uint32_t ROUTE_TABLE_LOCAL_NETWORK  = 97;
74const uint32_t ROUTE_TABLE_LEGACY_NETWORK = 98;
75const uint32_t ROUTE_TABLE_LEGACY_SYSTEM  = 99;
76
77const char* const ROUTE_TABLE_NAME_LOCAL_NETWORK  = "local_network";
78const char* const ROUTE_TABLE_NAME_LEGACY_NETWORK = "legacy_network";
79const char* const ROUTE_TABLE_NAME_LEGACY_SYSTEM  = "legacy_system";
80
81const char* const ROUTE_TABLE_NAME_LOCAL = "local";
82const char* const ROUTE_TABLE_NAME_MAIN  = "main";
83
84// None of our routes specify priority, which causes them to have the default
85// priority. For throw routes, we use a fixed priority of 100000. This is
86// because we use throw routes either for maximum-length routes (/32 for IPv4,
87// /128 for IPv6), which we never create with any other priority, or for
88// purposely-low-priority default routes that should never match if there is
89// any other route in the table.
90uint32_t PRIO_THROW = 100000;
91
92const char* const RouteController::LOCAL_MANGLE_INPUT = "routectrl_mangle_INPUT";
93
94// These values are upstream, but not yet in our headers.
95// TODO: delete these definitions when updating the headers.
96const uint16_t FRA_UID_RANGE = 20;
97struct fib_rule_uid_range {
98        __u32           start;
99        __u32           end;
100};
101
102const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6};
103
104const uid_t UID_ROOT = 0;
105const char* const IIF_LOOPBACK = "lo";
106const char* const IIF_NONE = NULL;
107const char* const OIF_NONE = NULL;
108const bool ACTION_ADD = true;
109const bool ACTION_DEL = false;
110const bool MODIFY_NON_UID_BASED_RULES = true;
111
112const char* const RT_TABLES_PATH = "/data/misc/net/rt_tables";
113const mode_t RT_TABLES_MODE = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;  // mode 0644, rw-r--r--
114
115// Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'"
116// warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t).
117constexpr uint16_t U16_RTA_LENGTH(uint16_t x) {
118    return RTA_LENGTH(x);
119}
120
121// These are practically const, but can't be declared so, because they are used to initialize
122// non-const pointers ("void* iov_base") in iovec arrays.
123rtattr FRATTR_PRIORITY  = { U16_RTA_LENGTH(sizeof(uint32_t)),           FRA_PRIORITY };
124rtattr FRATTR_TABLE     = { U16_RTA_LENGTH(sizeof(uint32_t)),           FRA_TABLE };
125rtattr FRATTR_FWMARK    = { U16_RTA_LENGTH(sizeof(uint32_t)),           FRA_FWMARK };
126rtattr FRATTR_FWMASK    = { U16_RTA_LENGTH(sizeof(uint32_t)),           FRA_FWMASK };
127rtattr FRATTR_UID_RANGE = { U16_RTA_LENGTH(sizeof(fib_rule_uid_range)), FRA_UID_RANGE };
128
129rtattr RTATTR_TABLE     = { U16_RTA_LENGTH(sizeof(uint32_t)),           RTA_TABLE };
130rtattr RTATTR_OIF       = { U16_RTA_LENGTH(sizeof(uint32_t)),           RTA_OIF };
131rtattr RTATTR_PRIO      = { U16_RTA_LENGTH(sizeof(uint32_t)),           RTA_PRIORITY };
132
133uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0};
134
135// END CONSTANTS ----------------------------------------------------------------------------------
136
137const char *actionName(uint16_t action) {
138    static const char *ops[4] = {"adding", "deleting", "getting", "???"};
139    return ops[action % 4];
140}
141
142const char *familyName(uint8_t family) {
143    switch (family) {
144        case AF_INET: return "IPv4";
145        case AF_INET6: return "IPv6";
146        default: return "???";
147    }
148}
149
150// No locks needed because RouteController is accessed only from one thread (in CommandListener).
151std::map<std::string, uint32_t> interfaceToTable;
152
153uint32_t getRouteTableForInterface(const char* interface) {
154    uint32_t index = if_nametoindex(interface);
155    if (index) {
156        index += RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX;
157        interfaceToTable[interface] = index;
158        return index;
159    }
160    // If the interface goes away if_nametoindex() will return 0 but we still need to know
161    // the index so we can remove the rules and routes.
162    auto iter = interfaceToTable.find(interface);
163    if (iter == interfaceToTable.end()) {
164        ALOGE("cannot find interface %s", interface);
165        return RT_TABLE_UNSPEC;
166    }
167    return iter->second;
168}
169
170void addTableName(uint32_t table, const std::string& name, std::string* contents) {
171    char tableString[UINT32_STRLEN];
172    snprintf(tableString, sizeof(tableString), "%u", table);
173    *contents += tableString;
174    *contents += " ";
175    *contents += name;
176    *contents += "\n";
177}
178
179// Doesn't return success/failure as the file is optional; it's okay if we fail to update it.
180void updateTableNamesFile() {
181    std::string contents;
182
183    addTableName(RT_TABLE_LOCAL, ROUTE_TABLE_NAME_LOCAL, &contents);
184    addTableName(RT_TABLE_MAIN,  ROUTE_TABLE_NAME_MAIN,  &contents);
185
186    addTableName(ROUTE_TABLE_LOCAL_NETWORK,  ROUTE_TABLE_NAME_LOCAL_NETWORK,  &contents);
187    addTableName(ROUTE_TABLE_LEGACY_NETWORK, ROUTE_TABLE_NAME_LEGACY_NETWORK, &contents);
188    addTableName(ROUTE_TABLE_LEGACY_SYSTEM,  ROUTE_TABLE_NAME_LEGACY_SYSTEM,  &contents);
189
190    for (const auto& entry : interfaceToTable) {
191        addTableName(entry.second, entry.first, &contents);
192    }
193
194    if (!WriteStringToFile(contents, RT_TABLES_PATH, RT_TABLES_MODE, AID_SYSTEM, AID_WIFI)) {
195        ALOGE("failed to write to %s (%s)", RT_TABLES_PATH, strerror(errno));
196        return;
197    }
198}
199
200// Returns 0 on success or negative errno on failure.
201int padInterfaceName(const char* input, char* name, size_t* length, uint16_t* padding) {
202    if (!input) {
203        *length = 0;
204        *padding = 0;
205        return 0;
206    }
207    *length = strlcpy(name, input, IFNAMSIZ) + 1;
208    if (*length > IFNAMSIZ) {
209        ALOGE("interface name too long (%zu > %u)", *length, IFNAMSIZ);
210        return -ENAMETOOLONG;
211    }
212    *padding = RTA_SPACE(*length) - RTA_LENGTH(*length);
213    return 0;
214}
215
216// Adds or removes a routing rule for IPv4 and IPv6.
217//
218// + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the table is
219//   unspecified. An unspecified table is not allowed when creating an FR_ACT_TO_TBL rule.
220// + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is
221//   ignored.
222// + If |iif| is non-NULL, the rule matches the specified incoming interface.
223// + If |oif| is non-NULL, the rule matches the specified outgoing interface.
224// + If |uidStart| and |uidEnd| are not INVALID_UID, the rule matches packets from UIDs in that
225//   range (inclusive). Otherwise, the rule matches packets from all UIDs.
226//
227// Returns 0 on success or negative errno on failure.
228WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint8_t ruleType,
229                                    uint32_t table, uint32_t fwmark, uint32_t mask, const char* iif,
230                                    const char* oif, uid_t uidStart, uid_t uidEnd) {
231    // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask.
232    if (fwmark & ~mask) {
233        ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark);
234        return -ERANGE;
235    }
236
237    // Interface names must include exactly one terminating NULL and be properly padded, or older
238    // kernels will refuse to delete rules.
239    char iifName[IFNAMSIZ], oifName[IFNAMSIZ];
240    size_t iifLength, oifLength;
241    uint16_t iifPadding, oifPadding;
242    if (int ret = padInterfaceName(iif, iifName, &iifLength, &iifPadding)) {
243        return ret;
244    }
245    if (int ret = padInterfaceName(oif, oifName, &oifLength, &oifPadding)) {
246        return ret;
247    }
248
249    // Either both start and end UID must be specified, or neither.
250    if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) {
251        ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd);
252        return -EUSERS;
253    }
254
255    bool isUidRule = (uidStart != INVALID_UID);
256
257    // Assemble a rule request and put it in an array of iovec structures.
258    fib_rule_hdr rule = {
259        .action = ruleType,
260        // Note that here we're implicitly setting rule.table to 0. When we want to specify a
261        // non-zero table, we do this via the FRATTR_TABLE attribute.
262    };
263
264    // Don't ever create a rule that looks up table 0, because table 0 is the local table.
265    // It's OK to specify a table ID of 0 when deleting a rule, because that doesn't actually select
266    // table 0, it's a wildcard that matches anything.
267    if (table == RT_TABLE_UNSPEC && rule.action == FR_ACT_TO_TBL && action != RTM_DELRULE) {
268        ALOGE("RT_TABLE_UNSPEC only allowed when deleting rules");
269        return -ENOTUNIQ;
270    }
271
272    rtattr fraIifName = { U16_RTA_LENGTH(iifLength), FRA_IIFNAME };
273    rtattr fraOifName = { U16_RTA_LENGTH(oifLength), FRA_OIFNAME };
274    struct fib_rule_uid_range uidRange = { uidStart, uidEnd };
275
276    iovec iov[] = {
277        { NULL,              0 },
278        { &rule,             sizeof(rule) },
279        { &FRATTR_PRIORITY,  sizeof(FRATTR_PRIORITY) },
280        { &priority,         sizeof(priority) },
281        { &FRATTR_TABLE,     table != RT_TABLE_UNSPEC ? sizeof(FRATTR_TABLE) : 0 },
282        { &table,            table != RT_TABLE_UNSPEC ? sizeof(table) : 0 },
283        { &FRATTR_FWMARK,    mask ? sizeof(FRATTR_FWMARK) : 0 },
284        { &fwmark,           mask ? sizeof(fwmark) : 0 },
285        { &FRATTR_FWMASK,    mask ? sizeof(FRATTR_FWMASK) : 0 },
286        { &mask,             mask ? sizeof(mask) : 0 },
287        { &FRATTR_UID_RANGE, isUidRule ? sizeof(FRATTR_UID_RANGE) : 0 },
288        { &uidRange,         isUidRule ? sizeof(uidRange) : 0 },
289        { &fraIifName,       iif != IIF_NONE ? sizeof(fraIifName) : 0 },
290        { iifName,           iifLength },
291        { PADDING_BUFFER,    iifPadding },
292        { &fraOifName,       oif != OIF_NONE ? sizeof(fraOifName) : 0 },
293        { oifName,           oifLength },
294        { PADDING_BUFFER,    oifPadding },
295    };
296
297    uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS;
298    for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) {
299        rule.family = AF_FAMILIES[i];
300        if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov), nullptr)) {
301            if (!(action == RTM_DELRULE && ret == -ENOENT && priority == RULE_PRIORITY_TETHERING)) {
302                // Don't log when deleting a tethering rule that's not there. This matches the
303                // behaviour of clearTetheringRules, which ignores ENOENT in this case.
304                ALOGE("Error %s %s rule: %s", actionName(action), familyName(rule.family),
305                      strerror(-ret));
306            }
307            return ret;
308        }
309    }
310
311    return 0;
312}
313
314WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
315                                    uint32_t fwmark, uint32_t mask, const char* iif,
316                                    const char* oif, uid_t uidStart, uid_t uidEnd) {
317    return modifyIpRule(action, priority, FR_ACT_TO_TBL, table, fwmark, mask, iif, oif, uidStart,
318                        uidEnd);
319}
320
321WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table,
322                                    uint32_t fwmark, uint32_t mask) {
323    return modifyIpRule(action, priority, table, fwmark, mask, IIF_NONE, OIF_NONE, INVALID_UID,
324                        INVALID_UID);
325}
326
327// Adds or deletes an IPv4 or IPv6 route.
328// Returns 0 on success or negative errno on failure.
329WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface,
330                                     const char* destination, const char* nexthop) {
331    // At least the destination must be non-null.
332    if (!destination) {
333        ALOGE("null destination");
334        return -EFAULT;
335    }
336
337    // Parse the prefix.
338    uint8_t rawAddress[sizeof(in6_addr)];
339    uint8_t family;
340    uint8_t prefixLength;
341    int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress),
342                                &prefixLength);
343    if (rawLength < 0) {
344        ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength));
345        return rawLength;
346    }
347
348    if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) {
349        ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress));
350        return -ENOBUFS;  // Cannot happen; parsePrefix only supports IPv4 and IPv6.
351    }
352
353    uint8_t type = RTN_UNICAST;
354    uint32_t ifindex;
355    uint8_t rawNexthop[sizeof(in6_addr)];
356
357    if (nexthop && !strcmp(nexthop, "unreachable")) {
358        type = RTN_UNREACHABLE;
359        // 'interface' is likely non-NULL, as the caller (modifyRoute()) likely used it to lookup
360        // the table number. But it's an error to specify an interface ("dev ...") or a nexthop for
361        // unreachable routes, so nuke them. (IPv6 allows them to be specified; IPv4 doesn't.)
362        interface = OIF_NONE;
363        nexthop = NULL;
364    } else if (nexthop && !strcmp(nexthop, "throw")) {
365        type = RTN_THROW;
366        interface = OIF_NONE;
367        nexthop = NULL;
368    } else {
369        // If an interface was specified, find the ifindex.
370        if (interface != OIF_NONE) {
371            ifindex = if_nametoindex(interface);
372            if (!ifindex) {
373                ALOGE("cannot find interface %s", interface);
374                return -ENODEV;
375            }
376        }
377
378        // If a nexthop was specified, parse it as the same family as the prefix.
379        if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) {
380            ALOGE("inet_pton failed for nexthop %s", nexthop);
381            return -EINVAL;
382        }
383    }
384
385    bool isDefaultThrowRoute = (type == RTN_THROW && prefixLength == 0);
386
387    // Assemble a rtmsg and put it in an array of iovec structures.
388    rtmsg route = {
389        .rtm_protocol = RTPROT_STATIC,
390        .rtm_type = type,
391        .rtm_family = family,
392        .rtm_dst_len = prefixLength,
393        .rtm_scope = static_cast<uint8_t>(nexthop ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK),
394    };
395
396    rtattr rtaDst     = { U16_RTA_LENGTH(rawLength), RTA_DST };
397    rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY };
398
399    iovec iov[] = {
400        { NULL,          0 },
401        { &route,        sizeof(route) },
402        { &RTATTR_TABLE, sizeof(RTATTR_TABLE) },
403        { &table,        sizeof(table) },
404        { &rtaDst,       sizeof(rtaDst) },
405        { rawAddress,    static_cast<size_t>(rawLength) },
406        { &RTATTR_OIF,   interface != OIF_NONE ? sizeof(RTATTR_OIF) : 0 },
407        { &ifindex,      interface != OIF_NONE ? sizeof(ifindex) : 0 },
408        { &rtaGateway,   nexthop ? sizeof(rtaGateway) : 0 },
409        { rawNexthop,    nexthop ? static_cast<size_t>(rawLength) : 0 },
410        { &RTATTR_PRIO,  isDefaultThrowRoute ? sizeof(RTATTR_PRIO) : 0 },
411        { &PRIO_THROW,   isDefaultThrowRoute ? sizeof(PRIO_THROW) : 0 },
412    };
413
414    uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS :
415                                                NETLINK_REQUEST_FLAGS;
416    int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov), nullptr);
417    if (ret) {
418        ALOGE("Error %s route %s -> %s %s to table %u: %s",
419              actionName(action), destination, nexthop, interface, table, strerror(-ret));
420    }
421    return ret;
422}
423
424// An iptables rule to mark incoming packets on a network with the netId of the network.
425//
426// This is so that the kernel can:
427// + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, ping
428//   replies, SYN-ACKs, etc).
429// + Mark sockets that accept connections from this interface so that the connection stays on the
430//   same interface.
431WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface,
432                                                Permission permission, bool add) {
433    Fwmark fwmark;
434
435    fwmark.netId = netId;
436    fwmark.explicitlySelected = true;
437    fwmark.protectedFromVpn = true;
438    fwmark.permission = permission;
439
440    std::string cmd = StringPrintf("%s %s -i %s -j MARK --set-mark 0x%x",
441                                   add ? "-A" : "-D", RouteController::LOCAL_MANGLE_INPUT,
442                                   interface, fwmark.intValue);
443    if (RouteController::iptablesRestoreCommandFunction(V4V6, "mangle", cmd, nullptr) != 0) {
444        ALOGE("failed to change iptables rule that sets incoming packet mark");
445        return -EREMOTEIO;
446    }
447
448    return 0;
449}
450
451// A rule to route responses to the local network forwarded via the VPN.
452//
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.
455WARN_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);
459}
460
461// A rule to route all traffic from a given set of UIDs to go over the VPN.
462//
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.
466WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd,
467                                             bool secure, bool add) {
468    Fwmark fwmark;
469    Fwmark mask;
470
471    fwmark.protectedFromVpn = false;
472    mask.protectedFromVpn = true;
473
474    uint32_t priority;
475
476    if (secure) {
477        priority = RULE_PRIORITY_SECURE_VPN;
478    } else {
479        priority = RULE_PRIORITY_BYPASSABLE_VPN;
480
481        fwmark.explicitlySelected = false;
482        mask.explicitlySelected = true;
483    }
484
485    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
486                        mask.intValue, IIF_LOOPBACK, OIF_NONE, uidStart, uidEnd);
487}
488
489// A rule to allow system apps to send traffic over this VPN even if they are not part of the target
490// set of UIDs.
491//
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.
494WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool secure,
495                                                     bool add) {
496    Fwmark fwmark;
497    Fwmark mask;
498
499    fwmark.netId = netId;
500    mask.netId = FWMARK_NET_ID_MASK;
501
502    fwmark.permission = PERMISSION_SYSTEM;
503    mask.permission = PERMISSION_SYSTEM;
504
505    uint32_t priority = secure ? RULE_PRIORITY_SECURE_VPN : RULE_PRIORITY_BYPASSABLE_VPN;
506
507    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
508                        mask.intValue);
509}
510
511// A rule to route traffic based on an explicitly chosen network.
512//
513// Supports apps that use the multinetwork APIs to restrict their traffic to a network.
514//
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().
518WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table,
519                                                 Permission permission, uid_t uidStart,
520                                                 uid_t uidEnd, bool add) {
521    Fwmark fwmark;
522    Fwmark mask;
523
524    fwmark.netId = netId;
525    mask.netId = FWMARK_NET_ID_MASK;
526
527    fwmark.explicitlySelected = true;
528    mask.explicitlySelected = true;
529
530    fwmark.permission = permission;
531    mask.permission = permission;
532
533    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table,
534                        fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd);
535}
536
537// A rule to route traffic based on a chosen outgoing interface.
538//
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).
541WARN_UNUSED_RESULT int modifyOutputInterfaceRules(const char* interface, uint32_t table,
542                                                  Permission permission, uid_t uidStart,
543                                                  uid_t uidEnd, bool add) {
544    Fwmark fwmark;
545    Fwmark mask;
546
547    fwmark.permission = permission;
548    mask.permission = permission;
549
550    // If this rule does not specify a UID range, then also add a corresponding high-priority rule
551    // for UID. This covers forwarded packets and system daemons such as the tethering DHCP server.
552    if (uidStart == INVALID_UID && uidEnd == INVALID_UID) {
553        if (int ret = modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_VPN_OVERRIDE_OIF,
554                                   table, fwmark.intValue, mask.intValue, IIF_NONE, interface,
555                                   UID_ROOT, UID_ROOT)) {
556            return ret;
557        }
558    }
559
560    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table,
561                        fwmark.intValue, mask.intValue, IIF_NONE, interface, uidStart, uidEnd);
562}
563
564// A rule to route traffic based on the chosen network.
565//
566// This is for sockets that have not explicitly requested a particular network, but have been
567// bound to one when they called connect(). This ensures that sockets connected on a particular
568// network stay on that network even if the default network changes.
569WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table, bool add) {
570    Fwmark fwmark;
571    Fwmark mask;
572
573    fwmark.netId = netId;
574    mask.netId = FWMARK_NET_ID_MASK;
575
576    fwmark.explicitlySelected = false;
577    mask.explicitlySelected = true;
578
579    fwmark.permission = PERMISSION_NONE;
580    mask.permission = PERMISSION_NONE;
581
582    return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table,
583                        fwmark.intValue, mask.intValue);
584}
585
586// A rule to enable split tunnel VPNs.
587//
588// If a packet with a VPN's netId doesn't find a route in the VPN's routing table, it's allowed to
589// go over the default network, provided it wasn't explicitly restricted to the VPN and has the
590// permissions required by the default network.
591WARN_UNUSED_RESULT int modifyVpnFallthroughRule(uint16_t action, unsigned vpnNetId,
592                                                const char* physicalInterface,
593                                                Permission permission) {
594    uint32_t table = getRouteTableForInterface(physicalInterface);
595    if (table == RT_TABLE_UNSPEC) {
596        return -ESRCH;
597    }
598
599    Fwmark fwmark;
600    Fwmark mask;
601
602    fwmark.netId = vpnNetId;
603    mask.netId = FWMARK_NET_ID_MASK;
604
605    fwmark.explicitlySelected = false;
606    mask.explicitlySelected = true;
607
608    fwmark.permission = permission;
609    mask.permission = permission;
610
611    return modifyIpRule(action, RULE_PRIORITY_VPN_FALLTHROUGH, table, fwmark.intValue,
612                        mask.intValue);
613}
614
615// Add rules to allow legacy routes added through the requestRouteToHost() API.
616WARN_UNUSED_RESULT int addLegacyRouteRules() {
617    Fwmark fwmark;
618    Fwmark mask;
619
620    fwmark.explicitlySelected = false;
621    mask.explicitlySelected = true;
622
623    // Rules to allow legacy routes to override the default network.
624    if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
625                               fwmark.intValue, mask.intValue)) {
626        return ret;
627    }
628    if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK,
629                               ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, mask.intValue)) {
630        return ret;
631    }
632
633    fwmark.permission = PERMISSION_SYSTEM;
634    mask.permission = PERMISSION_SYSTEM;
635
636    // A rule to allow legacy routes from system apps to override VPNs.
637    return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDE_SYSTEM, ROUTE_TABLE_LEGACY_SYSTEM,
638                        fwmark.intValue, mask.intValue);
639}
640
641// Add rules to lookup the local network when specified explicitly or otherwise.
642WARN_UNUSED_RESULT int addLocalNetworkRules(unsigned localNetId) {
643    if (int ret = modifyExplicitNetworkRule(localNetId, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
644                                            INVALID_UID, INVALID_UID, ACTION_ADD)) {
645        return ret;
646    }
647
648    Fwmark fwmark;
649    Fwmark mask;
650
651    fwmark.explicitlySelected = false;
652    mask.explicitlySelected = true;
653
654    return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LOCAL_NETWORK, ROUTE_TABLE_LOCAL_NETWORK,
655                        fwmark.intValue, mask.intValue);
656}
657
658int configureDummyNetwork() {
659    const char *interface = DummyNetwork::INTERFACE_NAME;
660    uint32_t table = getRouteTableForInterface(interface);
661    if (table == RT_TABLE_UNSPEC) {
662        // getRouteTableForInterface has already looged an error.
663        return -ESRCH;
664    }
665
666    ifc_init();
667    int ret = ifc_up(interface);
668    ifc_close();
669    if (ret) {
670        ALOGE("Can't bring up %s: %s", interface, strerror(errno));
671        return -errno;
672    }
673
674    if ((ret = modifyOutputInterfaceRules(interface, table, PERMISSION_NONE,
675                                          INVALID_UID, INVALID_UID, ACTION_ADD))) {
676        ALOGE("Can't create oif rules for %s: %s", interface, strerror(-ret));
677        return ret;
678    }
679
680    if ((ret = modifyIpRoute(RTM_NEWROUTE, table, interface, "0.0.0.0/0", NULL))) {
681        return ret;
682    }
683
684    if ((ret = modifyIpRoute(RTM_NEWROUTE, table, interface, "::/0", NULL))) {
685        return ret;
686    }
687
688    return 0;
689}
690
691// Add a new rule to look up the 'main' table, with the same selectors as the "default network"
692// rule, but with a lower priority. We will never create routes in the main table; it should only be
693// used for directly-connected routes implicitly created by the kernel when adding IP addresses.
694// This is necessary, for example, when adding a route through a directly-connected gateway: in
695// order to add the route, there must already be a directly-connected route that covers the gateway.
696WARN_UNUSED_RESULT int addDirectlyConnectedRule() {
697    Fwmark fwmark;
698    Fwmark mask;
699
700    fwmark.netId = NETID_UNSET;
701    mask.netId = FWMARK_NET_ID_MASK;
702
703    return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_DIRECTLY_CONNECTED, RT_TABLE_MAIN,
704                        fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, UID_ROOT, UID_ROOT);
705}
706
707// Add an explicit unreachable rule close to the end of the prioriy list to make it clear that
708// relying on the kernel-default "from all lookup main" rule at priority 32766 is not intended
709// behaviour. We do flush the kernel-default rules at startup, but having an explicit unreachable
710// rule will hopefully make things even clearer.
711WARN_UNUSED_RESULT int addUnreachableRule() {
712    return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, FR_ACT_UNREACHABLE, RT_TABLE_UNSPEC,
713                        MARK_UNSET, MARK_UNSET, IIF_NONE, OIF_NONE, INVALID_UID, INVALID_UID);
714}
715
716WARN_UNUSED_RESULT int modifyLocalNetwork(unsigned netId, const char* interface, bool add) {
717    if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
718        return ret;
719    }
720    return modifyOutputInterfaceRules(interface, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
721                                      INVALID_UID, INVALID_UID, add);
722}
723
724WARN_UNUSED_RESULT int modifyPhysicalNetwork(unsigned netId, const char* interface,
725                                             Permission permission, bool add) {
726    uint32_t table = getRouteTableForInterface(interface);
727    if (table == RT_TABLE_UNSPEC) {
728        return -ESRCH;
729    }
730
731    if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) {
732        return ret;
733    }
734    if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID,
735                                            add)) {
736        return ret;
737    }
738    if (int ret = modifyOutputInterfaceRules(interface, table, permission, INVALID_UID, INVALID_UID,
739                                            add)) {
740        return ret;
741    }
742
743    // Only set implicit rules for networks that don't require permissions.
744    //
745    // This is so that if the default network ceases to be the default network and then switches
746    // from requiring no permissions to requiring permissions, we ensure that apps only use the
747    // network if they explicitly select it. This is consistent with destroySocketsLackingPermission
748    // - it closes all sockets on the network except sockets that are explicitly selected.
749    //
750    // The lack of this rule only affects the special case above, because:
751    // - The only cases where we implicitly bind a socket to a network are the default network and
752    //   the bypassable VPN that applies to the app, if any.
753    // - This rule doesn't affect VPNs because they don't support permissions at all.
754    // - The default network doesn't require permissions. While we support doing this, the framework
755    //   never does it (partly because we'd end up in the situation where we tell apps that there is
756    //   a default network, but they can't use it).
757    // - If the network is still the default network, the presence or absence of this rule does not
758    //   matter.
759    //
760    // Therefore, for the lack of this rule to affect a socket, the socket has to have been
761    // implicitly bound to a network because at the time of connect() it was the default, and that
762    // network must no longer be the default, and must now require permissions.
763    if (permission == PERMISSION_NONE) {
764        return modifyImplicitNetworkRule(netId, table, add);
765    }
766    return 0;
767}
768
769WARN_UNUSED_RESULT int modifyRejectNonSecureNetworkRule(const UidRanges& uidRanges, bool add) {
770    Fwmark fwmark;
771    Fwmark mask;
772    fwmark.protectedFromVpn = false;
773    mask.protectedFromVpn = true;
774
775    for (const UidRange& range : uidRanges.getRanges()) {
776        if (int ret = modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE,
777                                   RULE_PRIORITY_PROHIBIT_NON_VPN, FR_ACT_PROHIBIT, RT_TABLE_UNSPEC,
778                                   fwmark.intValue, mask.intValue, IIF_LOOPBACK, OIF_NONE,
779                                   range.getStart(), range.getStop())) {
780            return ret;
781        }
782    }
783
784    return 0;
785}
786
787WARN_UNUSED_RESULT int modifyVirtualNetwork(unsigned netId, const char* interface,
788                                            const UidRanges& uidRanges, bool secure, bool add,
789                                            bool modifyNonUidBasedRules) {
790    uint32_t table = getRouteTableForInterface(interface);
791    if (table == RT_TABLE_UNSPEC) {
792        return -ESRCH;
793    }
794
795    for (const UidRange& range : uidRanges.getRanges()) {
796        if (int ret = modifyVpnUidRangeRule(table, range.getStart(), range.getStop(), secure, add))
797                {
798            return ret;
799        }
800        if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.getStart(),
801                                                range.getStop(), add)) {
802            return ret;
803        }
804        if (int ret = modifyOutputInterfaceRules(interface, table, PERMISSION_NONE,
805                                                 range.getStart(), range.getStop(), add)) {
806            return ret;
807        }
808    }
809
810    if (modifyNonUidBasedRules) {
811        if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
812            return ret;
813        }
814        if (int ret = modifyVpnOutputToLocalRule(interface, add)) {
815            return ret;
816        }
817        if (int ret = modifyVpnSystemPermissionRule(netId, table, secure, add)) {
818            return ret;
819        }
820        return modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, add);
821    }
822
823    return 0;
824}
825
826WARN_UNUSED_RESULT int modifyDefaultNetwork(uint16_t action, const char* interface,
827                                            Permission permission) {
828    uint32_t table = getRouteTableForInterface(interface);
829    if (table == RT_TABLE_UNSPEC) {
830        return -ESRCH;
831    }
832
833    Fwmark fwmark;
834    Fwmark mask;
835
836    fwmark.netId = NETID_UNSET;
837    mask.netId = FWMARK_NET_ID_MASK;
838
839    fwmark.permission = permission;
840    mask.permission = permission;
841
842    return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue,
843                        mask.intValue);
844}
845
846WARN_UNUSED_RESULT int modifyTetheredNetwork(uint16_t action, const char* inputInterface,
847                                             const char* outputInterface) {
848    uint32_t table = getRouteTableForInterface(outputInterface);
849    if (table == RT_TABLE_UNSPEC) {
850        return -ESRCH;
851    }
852
853    return modifyIpRule(action, RULE_PRIORITY_TETHERING, table, MARK_UNSET, MARK_UNSET,
854                        inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
855}
856
857// Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected
858// route, to the main table as well.
859// Returns 0 on success or negative errno on failure.
860WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination,
861                                   const char* nexthop, RouteController::TableType tableType) {
862    uint32_t table;
863    switch (tableType) {
864        case RouteController::INTERFACE: {
865            table = getRouteTableForInterface(interface);
866            if (table == RT_TABLE_UNSPEC) {
867                return -ESRCH;
868            }
869            break;
870        }
871        case RouteController::LOCAL_NETWORK: {
872            table = ROUTE_TABLE_LOCAL_NETWORK;
873            break;
874        }
875        case RouteController::LEGACY_NETWORK: {
876            table = ROUTE_TABLE_LEGACY_NETWORK;
877            break;
878        }
879        case RouteController::LEGACY_SYSTEM: {
880            table = ROUTE_TABLE_LEGACY_SYSTEM;
881            break;
882        }
883    }
884
885    int ret = modifyIpRoute(action, table, interface, destination, nexthop);
886    // Trying to add a route that already exists shouldn't cause an error.
887    if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST)) {
888        return ret;
889    }
890
891    return 0;
892}
893
894WARN_UNUSED_RESULT int clearTetheringRules(const char* inputInterface) {
895    int ret = 0;
896    while (ret == 0) {
897        ret = modifyIpRule(RTM_DELRULE, RULE_PRIORITY_TETHERING, 0, MARK_UNSET, MARK_UNSET,
898                           inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
899    }
900
901    if (ret == -ENOENT) {
902        return 0;
903    } else {
904        return ret;
905    }
906}
907
908uint32_t getRulePriority(const nlmsghdr *nlh) {
909    return getRtmU32Attribute(nlh, FRA_PRIORITY);
910}
911
912uint32_t getRouteTable(const nlmsghdr *nlh) {
913    return getRtmU32Attribute(nlh, RTA_TABLE);
914}
915
916WARN_UNUSED_RESULT int flushRules() {
917    NetlinkDumpFilter shouldDelete = [] (nlmsghdr *nlh) {
918        // Don't touch rules at priority 0 because by default they are used for local input.
919        return getRulePriority(nlh) != 0;
920    };
921    return rtNetlinkFlush(RTM_GETRULE, RTM_DELRULE, "rules", shouldDelete);
922}
923
924WARN_UNUSED_RESULT int flushRoutes(uint32_t table) {
925    NetlinkDumpFilter shouldDelete = [table] (nlmsghdr *nlh) {
926        return getRouteTable(nlh) == table;
927    };
928
929    return rtNetlinkFlush(RTM_GETROUTE, RTM_DELROUTE, "routes", shouldDelete);
930}
931
932// Returns 0 on success or negative errno on failure.
933WARN_UNUSED_RESULT int flushRoutes(const char* interface) {
934    uint32_t table = getRouteTableForInterface(interface);
935    if (table == RT_TABLE_UNSPEC) {
936        return -ESRCH;
937    }
938
939    int ret = flushRoutes(table);
940
941    // If we failed to flush routes, the caller may elect to keep this interface around, so keep
942    // track of its name.
943    if (ret == 0) {
944        interfaceToTable.erase(interface);
945    }
946
947    return ret;
948}
949
950int RouteController::Init(unsigned localNetId) {
951    if (int ret = flushRules()) {
952        return ret;
953    }
954    if (int ret = addLegacyRouteRules()) {
955        return ret;
956    }
957    if (int ret = addLocalNetworkRules(localNetId)) {
958        return ret;
959    }
960    if (int ret = addDirectlyConnectedRule()) {
961        return ret;
962    }
963    if (int ret = addUnreachableRule()) {
964        return ret;
965    }
966    // Don't complain if we can't add the dummy network, since not all devices support it.
967    configureDummyNetwork();
968
969    updateTableNamesFile();
970    return 0;
971}
972
973int RouteController::addInterfaceToLocalNetwork(unsigned netId, const char* interface) {
974    return modifyLocalNetwork(netId, interface, ACTION_ADD);
975}
976
977int RouteController::removeInterfaceFromLocalNetwork(unsigned netId, const char* interface) {
978    return modifyLocalNetwork(netId, interface, ACTION_DEL);
979}
980
981int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface,
982                                                   Permission permission) {
983    if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) {
984        return ret;
985    }
986    updateTableNamesFile();
987    return 0;
988}
989
990int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface,
991                                                        Permission permission) {
992    if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) {
993        return ret;
994    }
995    if (int ret = flushRoutes(interface)) {
996        return ret;
997    }
998    if (int ret = clearTetheringRules(interface)) {
999        return ret;
1000    }
1001    updateTableNamesFile();
1002    return 0;
1003}
1004
1005int RouteController::addInterfaceToVirtualNetwork(unsigned netId, const char* interface,
1006                                                  bool secure, const UidRanges& uidRanges) {
1007    if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
1008                                       MODIFY_NON_UID_BASED_RULES)) {
1009        return ret;
1010    }
1011    updateTableNamesFile();
1012    return 0;
1013}
1014
1015int RouteController::removeInterfaceFromVirtualNetwork(unsigned netId, const char* interface,
1016                                                       bool secure, const UidRanges& uidRanges) {
1017    if (int ret = modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
1018                                       MODIFY_NON_UID_BASED_RULES)) {
1019        return ret;
1020    }
1021    if (int ret = flushRoutes(interface)) {
1022        return ret;
1023    }
1024    updateTableNamesFile();
1025    return 0;
1026}
1027
1028int RouteController::modifyPhysicalNetworkPermission(unsigned netId, const char* interface,
1029                                                     Permission oldPermission,
1030                                                     Permission newPermission) {
1031    // Add the new rules before deleting the old ones, to avoid race conditions.
1032    if (int ret = modifyPhysicalNetwork(netId, interface, newPermission, ACTION_ADD)) {
1033        return ret;
1034    }
1035    return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL);
1036}
1037
1038int RouteController::addUsersToRejectNonSecureNetworkRule(const UidRanges& uidRanges) {
1039    return modifyRejectNonSecureNetworkRule(uidRanges, true);
1040}
1041
1042int RouteController::removeUsersFromRejectNonSecureNetworkRule(const UidRanges& uidRanges) {
1043    return modifyRejectNonSecureNetworkRule(uidRanges, false);
1044}
1045
1046int RouteController::addUsersToVirtualNetwork(unsigned netId, const char* interface, bool secure,
1047                                              const UidRanges& uidRanges) {
1048    return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_ADD,
1049                                !MODIFY_NON_UID_BASED_RULES);
1050}
1051
1052int RouteController::removeUsersFromVirtualNetwork(unsigned netId, const char* interface,
1053                                                   bool secure, const UidRanges& uidRanges) {
1054    return modifyVirtualNetwork(netId, interface, uidRanges, secure, ACTION_DEL,
1055                                !MODIFY_NON_UID_BASED_RULES);
1056}
1057
1058int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) {
1059    return modifyDefaultNetwork(RTM_NEWRULE, interface, permission);
1060}
1061
1062int RouteController::removeInterfaceFromDefaultNetwork(const char* interface,
1063                                                       Permission permission) {
1064    return modifyDefaultNetwork(RTM_DELRULE, interface, permission);
1065}
1066
1067int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop,
1068                              TableType tableType) {
1069    return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType);
1070}
1071
1072int RouteController::removeRoute(const char* interface, const char* destination,
1073                                 const char* nexthop, TableType tableType) {
1074    return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType);
1075}
1076
1077int RouteController::enableTethering(const char* inputInterface, const char* outputInterface) {
1078    return modifyTetheredNetwork(RTM_NEWRULE, inputInterface, outputInterface);
1079}
1080
1081int RouteController::disableTethering(const char* inputInterface, const char* outputInterface) {
1082    return modifyTetheredNetwork(RTM_DELRULE, inputInterface, outputInterface);
1083}
1084
1085int RouteController::addVirtualNetworkFallthrough(unsigned vpnNetId, const char* physicalInterface,
1086                                                  Permission permission) {
1087    return modifyVpnFallthroughRule(RTM_NEWRULE, vpnNetId, physicalInterface, permission);
1088}
1089
1090int RouteController::removeVirtualNetworkFallthrough(unsigned vpnNetId,
1091                                                     const char* physicalInterface,
1092                                                     Permission permission) {
1093    return modifyVpnFallthroughRule(RTM_DELRULE, vpnNetId, physicalInterface, permission);
1094}
1095
1096}  // namespace net
1097}  // namespace android
1098