RouteController.cpp revision 379bd33f7640e2c4bef902be0ed6cb96378c8c2e
15c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran/* 25c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * Copyright (C) 2014 The Android Open Source Project 35c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * 45c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * Licensed under the Apache License, Version 2.0 (the "License"); 55c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * you may not use this file except in compliance with the License. 65c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * You may obtain a copy of the License at 75c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * 85c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * http://www.apache.org/licenses/LICENSE-2.0 95c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * 105c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * Unless required by applicable law or agreed to in writing, software 115c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * distributed under the License is distributed on an "AS IS" BASIS, 125c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 135c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * See the License for the specific language governing permissions and 145c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran * limitations under the License. 155c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran */ 165c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 175c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran#include "RouteController.h" 185c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 195c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran#include "Fwmark.h" 205c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran#include "NetdConstants.h" 215c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 225c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran#include <logwrap/logwrap.h> 235c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran#include <net/if.h> 245c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 255c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandrannamespace { 265c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 27a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitticonst uint32_t RULE_PRIORITY_PER_NETWORK_EXPLICIT = 300; 28a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitticonst uint32_t RULE_PRIORITY_PER_NETWORK_OIF = 400; 29a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitticonst uint32_t RULE_PRIORITY_PER_NETWORK_NORMAL = 700; 305c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 315c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranconst bool FWMARK_USE_NET_ID = true; 325c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranconst bool FWMARK_USE_EXPLICIT = true; 335c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranconst bool FWMARK_USE_PROTECT = true; 345c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 355c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranuint32_t getRouteTableForInterface(const char* interface) { 36a48118062412f16ae712bfc8c8a539d3b6a85e47Sreeram Ramachandran uint32_t index = if_nametoindex(interface); 37a48118062412f16ae712bfc8c8a539d3b6a85e47Sreeram Ramachandran return index ? index + RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX : 0; 385c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} 395c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 40a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colittibool runIpRuleCommand(const char* action, uint32_t priority, uint32_t table, 41a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti uint32_t fwmark, uint32_t mask, const char* oif) { 42a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti 43a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti char priorityString[UINT32_STRLEN]; 44a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti char tableString[UINT32_STRLEN]; 45a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti snprintf(priorityString, sizeof(priorityString), "%u", priority); 46a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti snprintf(tableString, sizeof(tableString), "%u", table); 47a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti 48a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti char fwmarkString[sizeof("0x12345678/0x12345678")]; 49a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti snprintf(fwmarkString, sizeof(fwmarkString), "0x%x/0x%x", fwmark, mask); 50a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti 515c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran const char* version[] = {"-4", "-6"}; 525c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran for (size_t i = 0; i < ARRAY_SIZE(version); ++i) { 535c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran int argc = 0; 545c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran const char* argv[16]; 555c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 565c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = IP_PATH; 575c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = version[i]; 585c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = "rule"; 595c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = action; 605c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = "priority"; 61a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti argv[argc++] = priorityString; 625c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = "table"; 63a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti argv[argc++] = tableString; 64a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti if (mask) { 655c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = "fwmark"; 66a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti argv[argc++] = fwmarkString; 675c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 685c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran if (oif) { 695c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = "oif"; 705c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran argv[argc++] = oif; 715c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 725c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran if (android_fork_execvp(argc, const_cast<char**>(argv), NULL, false, false)) { 735c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return false; 745c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 755c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 765c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 775c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return true; 785c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} 795c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 80379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandranbool modifyRules(unsigned netId, const char* interface, Permission permission, bool add, 81379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran bool modifyIptables) { 825c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran uint32_t table = getRouteTableForInterface(interface); 835c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran if (!table) { 845c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return false; 855c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 865c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 875c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran const char* action = add ? ADD : DEL; 885c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 895c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // A rule to route traffic based on an explicitly chosen network. 905c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // 915c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // Supports apps that use the multinetwork APIs to restrict their traffic to a network. 925c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // 935c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // We don't really need to check the permission bits of the fwmark here, as they would've been 945c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // checked at the time the netId was set into the fwmark, but we do so to be consistent. 955c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran uint32_t fwmark = getFwmark(netId, FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, permission); 965c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran uint32_t mask = getFwmarkMask(FWMARK_USE_NET_ID, FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, 975c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran permission); 98a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti if (!runIpRuleCommand(action, RULE_PRIORITY_PER_NETWORK_EXPLICIT, table, fwmark, mask, NULL)) { 995c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return false; 1005c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 1015c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1025c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // A rule to route traffic based on a chosen outgoing interface. 1035c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // 1045c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already 1055c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // knows the outgoing interface (typically for link-local communications). 1065c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran fwmark = getFwmark(0, !FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, permission); 1075c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran mask = getFwmark(!FWMARK_USE_NET_ID, !FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, permission); 108a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti if (!runIpRuleCommand(action, RULE_PRIORITY_PER_NETWORK_OIF, table, fwmark, mask, interface)) { 1095c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return false; 1105c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 1115c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1125c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // A rule to route traffic based on the chosen network. 1135c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // 1145c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // This is for sockets that have not explicitly requested a particular network, but have been 1155c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // bound to one when they called connect(). This ensures that sockets connected on a particular 1165c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // network stay on that network even if the default network changes. 1175c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran fwmark = getFwmark(netId, !FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, permission); 1185c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran mask = getFwmarkMask(FWMARK_USE_NET_ID, !FWMARK_USE_EXPLICIT, !FWMARK_USE_PROTECT, permission); 119a10ac3214f6a582b7fdb66acc43c702731e53d81Lorenzo Colitti if (!runIpRuleCommand(action, RULE_PRIORITY_PER_NETWORK_NORMAL, table, fwmark, mask, NULL)) { 1205c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return false; 1215c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 1225c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1235c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // An iptables rule to mark incoming packets on a network with the netId of the network. 1245c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // 1255c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // This is so that the kernel can: 1265c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, 127a48118062412f16ae712bfc8c8a539d3b6a85e47Sreeram Ramachandran // ping replies). 1285c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // + Mark sockets that accept connections from this interface so that the connection stays on 1295c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran // the same interface. 130379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran if (modifyIptables) { 131379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran action = add ? "-A" : "-D"; 132379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran char markString[UINT32_HEX_STRLEN]; 133379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran snprintf(markString, sizeof(markString), "0x%x", netId); 134379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran if (execIptables(V4V6, "-t", "mangle", action, "INPUT", "-i", interface, "-j", "MARK", 135379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran "--set-mark", markString, NULL)) { 136379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran return false; 137379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran } 1385c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran } 1395c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1405c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran return true; 1415c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} 1425c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1435c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} // namespace 1445c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1455c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranbool RouteController::createNetwork(unsigned netId, const char* interface, Permission permission) { 146379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran return modifyRules(netId, interface, permission, true, true); 1475c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} 1485c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran 1495c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandranbool RouteController::destroyNetwork(unsigned netId, const char* interface, Permission permission) { 150379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran return modifyRules(netId, interface, permission, false, true); 151379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran // TODO: Flush the routing table. 152379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran} 153379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran 154379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandranbool RouteController::modifyNetworkPermission(unsigned netId, const char* interface, 155379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran Permission oldPermission, Permission newPermission) { 156379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran // Add the new rules before deleting the old ones, to avoid race conditions. 157379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran return modifyRules(netId, interface, newPermission, true, false) && 158379bd33f7640e2c4bef902be0ed6cb96378c8c2eSreeram Ramachandran modifyRules(netId, interface, oldPermission, false, false); 1595c181bf8ca0c89bd9e3e6d8e40bac53d0ee7082fSreeram Ramachandran} 160