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 "Fwmark.h"
31 #include "UidRanges.h"
32 #include "DummyNetwork.h"
33 
34 #include "base/file.h"
35 #define LOG_TAG "Netd"
36 #include "log/log.h"
37 #include "logwrap/logwrap.h"
38 #include "netutils/ifc.h"
39 #include "resolv_netid.h"
40 
41 using android::base::WriteStringToFile;
42 
43 namespace {
44 
45 // BEGIN CONSTANTS --------------------------------------------------------------------------------
46 
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;
63 
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;
67 
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";
71 
72 const char* const ROUTE_TABLE_NAME_LOCAL = "local";
73 const char* const ROUTE_TABLE_NAME_MAIN  = "main";
74 
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.");
84 
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;
87 
88 const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0};
89 
90 const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6};
91 
92 const char* const IP_VERSIONS[] = {"-4", "-6"};
93 
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;
101 
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--
104 
105 const unsigned ROUTE_FLUSH_ATTEMPTS = 2;
106 
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).
U16_RTA_LENGTH(uint16_t x)109 constexpr uint16_t U16_RTA_LENGTH(uint16_t x) {
110     return RTA_LENGTH(x);
111 }
112 
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 };
121 
122 rtattr RTATTR_TABLE     = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE };
123 rtattr RTATTR_OIF       = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF };
124 
125 uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0};
126 
127 // END CONSTANTS ----------------------------------------------------------------------------------
128 
129 // No locks needed because RouteController is accessed only from one thread (in CommandListener).
130 std::map<std::string, uint32_t> interfaceToTable;
131 
getRouteTableForInterface(const char * interface)132 uint32_t getRouteTableForInterface(const char* interface) {
133     uint32_t index = if_nametoindex(interface);
134     if (index) {
135         index += RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX;
136         interfaceToTable[interface] = index;
137         return index;
138     }
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;
145     }
146     return iter->second;
147 }
148 
addTableName(uint32_t table,const std::string & name,std::string * contents)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;
153     *contents += " ";
154     *contents += name;
155     *contents += "\n";
156 }
157 
158 // Doesn't return success/failure as the file is optional; it's okay if we fail to update it.
updateTableNamesFile()159 void updateTableNamesFile() {
160     std::string contents;
161 
162     addTableName(RT_TABLE_LOCAL, ROUTE_TABLE_NAME_LOCAL, &contents);
163     addTableName(RT_TABLE_MAIN,  ROUTE_TABLE_NAME_MAIN,  &contents);
164 
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);
168 
169     for (const auto& entry : interfaceToTable) {
170         addTableName(entry.second, entry.first, &contents);
171     }
172 
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));
175         return;
176     }
177 }
178 
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.
sendNetlinkRequest(uint16_t action,uint16_t flags,iovec * iov,int iovlen)183 WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) {
184     nlmsghdr nlmsg = {
185         .nlmsg_type = action,
186         .nlmsg_flags = flags,
187     };
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;
192     }
193 
194     int ret;
195     struct {
196         nlmsghdr msg;
197         nlmsgerr err;
198     } response;
199 
200     int sock = socket(AF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_ROUTE);
201     if (sock != -1 &&
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.
208             if (ret) {
209                 ALOGE("netlink response contains error (%s)", strerror(-ret));
210             }
211         } else {
212             ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response));
213             ret = -EBADMSG;
214         }
215     } else {
216         ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno));
217         ret = -errno;
218     }
219 
220     if (sock != -1) {
221         close(sock);
222     }
223 
224     return ret;
225 }
226 
227 // Returns 0 on success or negative errno on failure.
padInterfaceName(const char * input,char * name,size_t * length,uint16_t * padding)228 int padInterfaceName(const char* input, char* name, size_t* length, uint16_t* padding) {
229     if (!input) {
230         *length = 0;
231         *padding = 0;
232         return 0;
233     }
234     *length = strlcpy(name, input, IFNAMSIZ) + 1;
235     if (*length > IFNAMSIZ) {
236         ALOGE("interface name too long (%zu > %u)", *length, IFNAMSIZ);
237         return -ENAMETOOLONG;
238     }
239     *padding = RTA_SPACE(*length) - RTA_LENGTH(*length);
240     return 0;
241 }
242 
243 // Adds or removes a routing rule for IPv4 and IPv6.
244 //
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
250 //   ignored.
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.
255 //
256 // Returns 0 on success or negative errno on failure.
modifyIpRule(uint16_t action,uint32_t priority,uint32_t table,uint32_t fwmark,uint32_t mask,const char * iif,const char * oif,uid_t uidStart,uid_t uidEnd)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);
263         return -ERANGE;
264     }
265 
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)) {
272         return ret;
273     }
274     if (int ret = padInterfaceName(oif, oifName, &oifLength, &oifPadding)) {
275         return ret;
276     }
277 
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);
281         return -EUSERS;
282     }
283     bool isUidRule = (uidStart != INVALID_UID);
284 
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 :
288                                                                                FR_ACT_UNREACHABLE),
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.
291     };
292 
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");
298         return -ENOTUNIQ;
299     }
300 
301     rtattr fraIifName = { U16_RTA_LENGTH(iifLength), FRA_IIFNAME };
302     rtattr fraOifName = { U16_RTA_LENGTH(oifLength), FRA_OIFNAME };
303 
304     iovec iov[] = {
305         { NULL,              0 },
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 },
325     };
326 
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))) {
331             return ret;
332         }
333     }
334 
335     return 0;
336 }
337 
modifyIpRule(uint16_t action,uint32_t priority,uint32_t table,uint32_t fwmark,uint32_t mask)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,
341                         INVALID_UID);
342 }
343 
344 // Adds or deletes an IPv4 or IPv6 route.
345 // Returns 0 on success or negative errno on failure.
modifyIpRoute(uint16_t action,uint32_t table,const char * interface,const char * destination,const char * nexthop)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.
349     if (!destination) {
350         ALOGE("null destination");
351         return -EFAULT;
352     }
353 
354     // Parse the prefix.
355     uint8_t rawAddress[sizeof(in6_addr)];
356     uint8_t family;
357     uint8_t prefixLength;
358     int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress),
359                                 &prefixLength);
360     if (rawLength < 0) {
361         ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength));
362         return rawLength;
363     }
364 
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.
368     }
369 
370     uint8_t type = RTN_UNICAST;
371     uint32_t ifindex;
372     uint8_t rawNexthop[sizeof(in6_addr)];
373 
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;
380         nexthop = NULL;
381     } else if (nexthop && !strcmp(nexthop, "throw")) {
382         type = RTN_THROW;
383         interface = OIF_NONE;
384         nexthop = NULL;
385     } else {
386         // If an interface was specified, find the ifindex.
387         if (interface != OIF_NONE) {
388             ifindex = if_nametoindex(interface);
389             if (!ifindex) {
390                 ALOGE("cannot find interface %s", interface);
391                 return -ENODEV;
392             }
393         }
394 
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);
398             return -EINVAL;
399         }
400     }
401 
402     // Assemble a rtmsg and put it in an array of iovec structures.
403     rtmsg route = {
404         .rtm_protocol = RTPROT_STATIC,
405         .rtm_type = type,
406         .rtm_family = family,
407         .rtm_dst_len = prefixLength,
408         .rtm_scope = static_cast<uint8_t>(nexthop ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK),
409     };
410 
411     rtattr rtaDst     = { U16_RTA_LENGTH(rawLength), RTA_DST };
412     rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY };
413 
414     iovec iov[] = {
415         { NULL,          0 },
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 },
425     };
426 
427     uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS :
428                                                 NETLINK_REQUEST_FLAGS;
429     return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov));
430 }
431 
432 // An iptables rule to mark incoming packets on a network with the netId of the network.
433 //
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
438 //   same interface.
modifyIncomingPacketMark(unsigned netId,const char * interface,Permission permission,bool add)439 WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface,
440                                                 Permission permission, bool add) {
441     Fwmark fwmark;
442 
443     fwmark.netId = netId;
444     fwmark.explicitlySelected = true;
445     fwmark.protectedFromVpn = true;
446     fwmark.permission = permission;
447 
448     char markString[UINT32_HEX_STRLEN];
449     snprintf(markString, sizeof(markString), "0x%x", fwmark.intValue);
450 
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");
454         return -EREMOTEIO;
455     }
456 
457     return 0;
458 }
459 
460 // A rule to route responses to the local network forwarded via the VPN.
461 //
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.
modifyVpnOutputToLocalRule(const char * vpnInterface,bool add)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);
468 }
469 
470 // A rule to route all traffic from a given set of UIDs to go over the VPN.
471 //
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.
modifyVpnUidRangeRule(uint32_t table,uid_t uidStart,uid_t uidEnd,bool secure,bool add)475 WARN_UNUSED_RESULT int modifyVpnUidRangeRule(uint32_t table, uid_t uidStart, uid_t uidEnd,
476                                              bool secure, bool add) {
477     Fwmark fwmark;
478     Fwmark mask;
479 
480     fwmark.protectedFromVpn = false;
481     mask.protectedFromVpn = true;
482 
483     uint32_t priority;
484 
485     if (secure) {
486         priority = RULE_PRIORITY_SECURE_VPN;
487     } else {
488         priority = RULE_PRIORITY_BYPASSABLE_VPN;
489 
490         fwmark.explicitlySelected = false;
491         mask.explicitlySelected = true;
492     }
493 
494     return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
495                         mask.intValue, IIF_LOOPBACK, OIF_NONE, uidStart, uidEnd);
496 }
497 
498 // A rule to allow system apps to send traffic over this VPN even if they are not part of the target
499 // set of UIDs.
500 //
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.
modifyVpnSystemPermissionRule(unsigned netId,uint32_t table,bool secure,bool add)503 WARN_UNUSED_RESULT int modifyVpnSystemPermissionRule(unsigned netId, uint32_t table, bool secure,
504                                                      bool add) {
505     Fwmark fwmark;
506     Fwmark mask;
507 
508     fwmark.netId = netId;
509     mask.netId = FWMARK_NET_ID_MASK;
510 
511     fwmark.permission = PERMISSION_SYSTEM;
512     mask.permission = PERMISSION_SYSTEM;
513 
514     uint32_t priority = secure ? RULE_PRIORITY_SECURE_VPN : RULE_PRIORITY_BYPASSABLE_VPN;
515 
516     return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, priority, table, fwmark.intValue,
517                         mask.intValue);
518 }
519 
520 // A rule to route traffic based on an explicitly chosen network.
521 //
522 // Supports apps that use the multinetwork APIs to restrict their traffic to a network.
523 //
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().
modifyExplicitNetworkRule(unsigned netId,uint32_t table,Permission permission,uid_t uidStart,uid_t uidEnd,bool add)527 WARN_UNUSED_RESULT int modifyExplicitNetworkRule(unsigned netId, uint32_t table,
528                                                  Permission permission, uid_t uidStart,
529                                                  uid_t uidEnd, bool add) {
530     Fwmark fwmark;
531     Fwmark mask;
532 
533     fwmark.netId = netId;
534     mask.netId = FWMARK_NET_ID_MASK;
535 
536     fwmark.explicitlySelected = true;
537     mask.explicitlySelected = true;
538 
539     fwmark.permission = permission;
540     mask.permission = permission;
541 
542     return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_EXPLICIT_NETWORK, table,
543                         fwmark.intValue, mask.intValue, IIF_NONE, OIF_NONE, uidStart, uidEnd);
544 }
545 
546 // A rule to route traffic based on a chosen outgoing interface.
547 //
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).
modifyOutputInterfaceRules(const char * interface,uint32_t table,Permission permission,uid_t uidStart,uid_t uidEnd,bool add)550 WARN_UNUSED_RESULT int modifyOutputInterfaceRules(const char* interface, uint32_t table,
551                                                   Permission permission, uid_t uidStart,
552                                                   uid_t uidEnd, bool add) {
553     Fwmark fwmark;
554     Fwmark mask;
555 
556     fwmark.permission = permission;
557     mask.permission = permission;
558 
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)) {
565             return ret;
566         }
567     }
568 
569     return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_OUTPUT_INTERFACE, table,
570                         fwmark.intValue, mask.intValue, IIF_NONE, interface, uidStart, uidEnd);
571 }
572 
573 // A rule to route traffic based on the chosen network.
574 //
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.
modifyImplicitNetworkRule(unsigned netId,uint32_t table,Permission permission,bool add)578 WARN_UNUSED_RESULT int modifyImplicitNetworkRule(unsigned netId, uint32_t table,
579                                                  Permission permission, bool add) {
580     Fwmark fwmark;
581     Fwmark mask;
582 
583     fwmark.netId = netId;
584     mask.netId = FWMARK_NET_ID_MASK;
585 
586     fwmark.explicitlySelected = false;
587     mask.explicitlySelected = true;
588 
589     fwmark.permission = permission;
590     mask.permission = permission;
591 
592     return modifyIpRule(add ? RTM_NEWRULE : RTM_DELRULE, RULE_PRIORITY_IMPLICIT_NETWORK, table,
593                         fwmark.intValue, mask.intValue);
594 }
595 
596 // A rule to enable split tunnel VPNs.
597 //
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.
modifyVpnFallthroughRule(uint16_t action,unsigned vpnNetId,const char * physicalInterface,Permission permission)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) {
606         return -ESRCH;
607     }
608 
609     Fwmark fwmark;
610     Fwmark mask;
611 
612     fwmark.netId = vpnNetId;
613     mask.netId = FWMARK_NET_ID_MASK;
614 
615     fwmark.explicitlySelected = false;
616     mask.explicitlySelected = true;
617 
618     fwmark.permission = permission;
619     mask.permission = permission;
620 
621     return modifyIpRule(action, RULE_PRIORITY_VPN_FALLTHROUGH, table, fwmark.intValue,
622                         mask.intValue);
623 }
624 
625 // Add rules to allow legacy routes added through the requestRouteToHost() API.
addLegacyRouteRules()626 WARN_UNUSED_RESULT int addLegacyRouteRules() {
627     Fwmark fwmark;
628     Fwmark mask;
629 
630     fwmark.explicitlySelected = false;
631     mask.explicitlySelected = true;
632 
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)) {
636         return ret;
637     }
638     if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY_NETWORK,
639                                ROUTE_TABLE_LEGACY_NETWORK, fwmark.intValue, mask.intValue)) {
640         return ret;
641     }
642 
643     fwmark.permission = PERMISSION_SYSTEM;
644     mask.permission = PERMISSION_SYSTEM;
645 
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);
649 }
650 
651 // Add rules to lookup the local network when specified explicitly or otherwise.
addLocalNetworkRules(unsigned localNetId)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)) {
655         return ret;
656     }
657 
658     Fwmark fwmark;
659     Fwmark mask;
660 
661     fwmark.explicitlySelected = false;
662     mask.explicitlySelected = true;
663 
664     return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LOCAL_NETWORK, ROUTE_TABLE_LOCAL_NETWORK,
665                         fwmark.intValue, mask.intValue);
666 }
667 
configureDummyNetwork()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.
673         return -ESRCH;
674     }
675 
676     ifc_init();
677     int ret = ifc_up(interface);
678     ifc_close();
679     if (ret) {
680         ALOGE("Can't bring up %s: %s", interface, strerror(errno));
681         return -errno;
682     }
683 
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));
687         return ret;
688     }
689 
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));
692         return ret;
693     }
694 
695     if ((ret = modifyIpRoute(RTM_NEWROUTE, table, interface, "::/0", NULL))) {
696         ALOGE("Can't add IPv6 default route to %s: %s", interface, strerror(-ret));
697         return ret;
698     }
699 
700     return 0;
701 }
702 
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.
addDirectlyConnectedRule()708 WARN_UNUSED_RESULT int addDirectlyConnectedRule() {
709     Fwmark fwmark;
710     Fwmark mask;
711 
712     fwmark.netId = NETID_UNSET;
713     mask.netId = FWMARK_NET_ID_MASK;
714 
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);
717 }
718 
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.
addUnreachableRule()723 WARN_UNUSED_RESULT int addUnreachableRule() {
724     return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, RT_TABLE_UNSPEC, MARK_UNSET,
725                         MARK_UNSET);
726 }
727 
modifyLocalNetwork(unsigned netId,const char * interface,bool add)728 WARN_UNUSED_RESULT int modifyLocalNetwork(unsigned netId, const char* interface, bool add) {
729     if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
730         return ret;
731     }
732     return modifyOutputInterfaceRules(interface, ROUTE_TABLE_LOCAL_NETWORK, PERMISSION_NONE,
733                                       INVALID_UID, INVALID_UID, add);
734 }
735 
modifyPhysicalNetwork(unsigned netId,const char * interface,Permission permission,bool 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) {
740         return -ESRCH;
741     }
742 
743     if (int ret = modifyIncomingPacketMark(netId, interface, permission, add)) {
744         return ret;
745     }
746     if (int ret = modifyExplicitNetworkRule(netId, table, permission, INVALID_UID, INVALID_UID,
747                                             add)) {
748         return ret;
749     }
750     if (int ret = modifyOutputInterfaceRules(interface, table, permission, INVALID_UID, INVALID_UID,
751                                             add)) {
752         return ret;
753     }
754     return modifyImplicitNetworkRule(netId, table, permission, add);
755 }
756 
modifyVirtualNetwork(unsigned netId,const char * interface,const UidRanges & uidRanges,bool secure,bool add,bool modifyNonUidBasedRules)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) {
762         return -ESRCH;
763     }
764 
765     for (const UidRanges::Range& range : uidRanges.getRanges()) {
766         if (int ret = modifyVpnUidRangeRule(table, range.first, range.second, secure, add)) {
767             return ret;
768         }
769         if (int ret = modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, range.first,
770                                                 range.second, add)) {
771             return ret;
772         }
773         if (int ret = modifyOutputInterfaceRules(interface, table, PERMISSION_NONE, range.first,
774                                                  range.second, add)) {
775             return ret;
776         }
777     }
778 
779     if (modifyNonUidBasedRules) {
780         if (int ret = modifyIncomingPacketMark(netId, interface, PERMISSION_NONE, add)) {
781             return ret;
782         }
783         if (int ret = modifyVpnOutputToLocalRule(interface, add)) {
784             return ret;
785         }
786         if (int ret = modifyVpnSystemPermissionRule(netId, table, secure, add)) {
787             return ret;
788         }
789         return modifyExplicitNetworkRule(netId, table, PERMISSION_NONE, UID_ROOT, UID_ROOT, add);
790     }
791 
792     return 0;
793 }
794 
modifyDefaultNetwork(uint16_t action,const char * interface,Permission permission)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) {
799         return -ESRCH;
800     }
801 
802     Fwmark fwmark;
803     Fwmark mask;
804 
805     fwmark.netId = NETID_UNSET;
806     mask.netId = FWMARK_NET_ID_MASK;
807 
808     fwmark.permission = permission;
809     mask.permission = permission;
810 
811     return modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue,
812                         mask.intValue);
813 }
814 
modifyTetheredNetwork(uint16_t action,const char * inputInterface,const char * outputInterface)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) {
819         return -ESRCH;
820     }
821 
822     return modifyIpRule(action, RULE_PRIORITY_TETHERING, table, MARK_UNSET, MARK_UNSET,
823                         inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
824 }
825 
826 // Returns 0 on success or negative errno on failure.
flushRules()827 WARN_UNUSED_RESULT int flushRules() {
828     for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
829         const char* argv[] = {
830             IP_PATH,
831             IP_VERSIONS[i],
832             "rule",
833             "flush",
834         };
835         if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) {
836             ALOGE("failed to flush rules");
837             return -EREMOTEIO;
838         }
839     }
840     return 0;
841 }
842 
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.
modifyRoute(uint16_t action,const char * interface,const char * destination,const char * nexthop,RouteController::TableType tableType)846 WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination,
847                                    const char* nexthop, RouteController::TableType tableType) {
848     uint32_t table;
849     switch (tableType) {
850         case RouteController::INTERFACE: {
851             table = getRouteTableForInterface(interface);
852             if (table == RT_TABLE_UNSPEC) {
853                 return -ESRCH;
854             }
855             break;
856         }
857         case RouteController::LOCAL_NETWORK: {
858             table = ROUTE_TABLE_LOCAL_NETWORK;
859             break;
860         }
861         case RouteController::LEGACY_NETWORK: {
862             table = ROUTE_TABLE_LEGACY_NETWORK;
863             break;
864         }
865         case RouteController::LEGACY_SYSTEM: {
866             table = ROUTE_TABLE_LEGACY_SYSTEM;
867             break;
868         }
869     }
870 
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)) {
874         return ret;
875     }
876 
877     return 0;
878 }
879 
880 // Returns 0 on success or negative errno on failure.
flushRoutes(const char * interface)881 WARN_UNUSED_RESULT int flushRoutes(const char* interface) {
882     uint32_t table = getRouteTableForInterface(interface);
883     if (table == RT_TABLE_UNSPEC) {
884         return -ESRCH;
885     }
886 
887     char tableString[UINT32_STRLEN];
888     snprintf(tableString, sizeof(tableString), "%u", table);
889 
890     int ret = 0;
891     for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) {
892         const char* argv[] = {
893             IP_PATH,
894             IP_VERSIONS[i],
895             "route",
896             "flush",
897             "table",
898             tableString,
899         };
900 
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.
905         //
906         // TODO: replace this with our own netlink code.
907         unsigned attempts = 0;
908         int err;
909         do {
910             err = android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv),
911                                       NULL, false, false);
912             ++attempts;
913         } while (err != 0 && attempts < ROUTE_FLUSH_ATTEMPTS);
914         if (err) {
915             ALOGE("failed to flush %s routes in table %s after %d attempts",
916                   IP_VERSIONS[i], tableString, attempts);
917             ret = -EREMOTEIO;
918         }
919     }
920 
921     // If we failed to flush routes, the caller may elect to keep this interface around, so keep
922     // track of its name.
923     if (!ret) {
924         interfaceToTable.erase(interface);
925     }
926 
927     return ret;
928 }
929 
clearTetheringRules(const char * inputInterface)930 WARN_UNUSED_RESULT int clearTetheringRules(const char* inputInterface) {
931     int ret = 0;
932     while (ret == 0) {
933         ret = modifyIpRule(RTM_DELRULE, RULE_PRIORITY_TETHERING, 0, MARK_UNSET, MARK_UNSET,
934                            inputInterface, OIF_NONE, INVALID_UID, INVALID_UID);
935     }
936 
937     if (ret == -ENOENT) {
938         return 0;
939     } else {
940         return ret;
941     }
942 }
943 
944 }  // namespace
945 
Init(unsigned localNetId)946 int RouteController::Init(unsigned localNetId) {
947     if (int ret = flushRules()) {
948         return ret;
949     }
950     if (int ret = addLegacyRouteRules()) {
951         return ret;
952     }
953     if (int ret = addLocalNetworkRules(localNetId)) {
954         return ret;
955     }
956     if (int ret = addDirectlyConnectedRule()) {
957         return ret;
958     }
959     if (int ret = addUnreachableRule()) {
960         return ret;
961     }
962     // Don't complain if we can't add the dummy network, since not all devices support it.
963     configureDummyNetwork();
964 
965     updateTableNamesFile();
966     return 0;
967 }
968 
addInterfaceToLocalNetwork(unsigned netId,const char * interface)969 int RouteController::addInterfaceToLocalNetwork(unsigned netId, const char* interface) {
970     return modifyLocalNetwork(netId, interface, ACTION_ADD);
971 }
972 
removeInterfaceFromLocalNetwork(unsigned netId,const char * interface)973 int RouteController::removeInterfaceFromLocalNetwork(unsigned netId, const char* interface) {
974     return modifyLocalNetwork(netId, interface, ACTION_DEL);
975 }
976 
addInterfaceToPhysicalNetwork(unsigned netId,const char * interface,Permission permission)977 int RouteController::addInterfaceToPhysicalNetwork(unsigned netId, const char* interface,
978                                                    Permission permission) {
979     if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_ADD)) {
980         return ret;
981     }
982     updateTableNamesFile();
983     return 0;
984 }
985 
removeInterfaceFromPhysicalNetwork(unsigned netId,const char * interface,Permission permission)986 int RouteController::removeInterfaceFromPhysicalNetwork(unsigned netId, const char* interface,
987                                                         Permission permission) {
988     if (int ret = modifyPhysicalNetwork(netId, interface, permission, ACTION_DEL)) {
989         return ret;
990     }
991     if (int ret = flushRoutes(interface)) {
992         return ret;
993     }
994     if (int ret = clearTetheringRules(interface)) {
995         return ret;
996     }
997     updateTableNamesFile();
998     return 0;
999 }
1000 
addInterfaceToVirtualNetwork(unsigned netId,const char * interface,bool secure,const UidRanges & uidRanges)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)) {
1005         return ret;
1006     }
1007     updateTableNamesFile();
1008     return 0;
1009 }
1010 
removeInterfaceFromVirtualNetwork(unsigned netId,const char * interface,bool secure,const UidRanges & uidRanges)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)) {
1015         return ret;
1016     }
1017     if (int ret = flushRoutes(interface)) {
1018         return ret;
1019     }
1020     updateTableNamesFile();
1021     return 0;
1022 }
1023 
modifyPhysicalNetworkPermission(unsigned netId,const char * interface,Permission oldPermission,Permission newPermission)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)) {
1029         return ret;
1030     }
1031     return modifyPhysicalNetwork(netId, interface, oldPermission, ACTION_DEL);
1032 }
1033 
addUsersToVirtualNetwork(unsigned netId,const char * interface,bool secure,const UidRanges & uidRanges)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);
1038 }
1039 
removeUsersFromVirtualNetwork(unsigned netId,const char * interface,bool secure,const UidRanges & uidRanges)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);
1044 }
1045 
addInterfaceToDefaultNetwork(const char * interface,Permission permission)1046 int RouteController::addInterfaceToDefaultNetwork(const char* interface, Permission permission) {
1047     return modifyDefaultNetwork(RTM_NEWRULE, interface, permission);
1048 }
1049 
removeInterfaceFromDefaultNetwork(const char * interface,Permission permission)1050 int RouteController::removeInterfaceFromDefaultNetwork(const char* interface,
1051                                                        Permission permission) {
1052     return modifyDefaultNetwork(RTM_DELRULE, interface, permission);
1053 }
1054 
addRoute(const char * interface,const char * destination,const char * nexthop,TableType tableType)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);
1058 }
1059 
removeRoute(const char * interface,const char * destination,const char * nexthop,TableType 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);
1063 }
1064 
enableTethering(const char * inputInterface,const char * outputInterface)1065 int RouteController::enableTethering(const char* inputInterface, const char* outputInterface) {
1066     return modifyTetheredNetwork(RTM_NEWRULE, inputInterface, outputInterface);
1067 }
1068 
disableTethering(const char * inputInterface,const char * outputInterface)1069 int RouteController::disableTethering(const char* inputInterface, const char* outputInterface) {
1070     return modifyTetheredNetwork(RTM_DELRULE, inputInterface, outputInterface);
1071 }
1072 
addVirtualNetworkFallthrough(unsigned vpnNetId,const char * physicalInterface,Permission permission)1073 int RouteController::addVirtualNetworkFallthrough(unsigned vpnNetId, const char* physicalInterface,
1074                                                   Permission permission) {
1075     return modifyVpnFallthroughRule(RTM_NEWRULE, vpnNetId, physicalInterface, permission);
1076 }
1077 
removeVirtualNetworkFallthrough(unsigned vpnNetId,const char * physicalInterface,Permission permission)1078 int RouteController::removeVirtualNetworkFallthrough(unsigned vpnNetId,
1079                                                      const char* physicalInterface,
1080                                                      Permission permission) {
1081     return modifyVpnFallthroughRule(RTM_DELRULE, vpnNetId, physicalInterface, permission);
1082 }
1083