| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "RouteController.h" |
| |
| #include "Fwmark.h" |
| #include "UidRanges.h" |
| |
| #define LOG_TAG "Netd" |
| #include "log/log.h" |
| #include "logwrap/logwrap.h" |
| |
| #include <arpa/inet.h> |
| #include <linux/fib_rules.h> |
| #include <map> |
| #include <net/if.h> |
| |
| namespace { |
| |
| // BEGIN CONSTANTS -------------------------------------------------------------------------------- |
| |
| const uint32_t RULE_PRIORITY_VPN_OVERRIDES = 11000; |
| const uint32_t RULE_PRIORITY_SECURE_VPN = 12000; |
| const uint32_t RULE_PRIORITY_EXPLICIT_NETWORK = 13000; |
| const uint32_t RULE_PRIORITY_OUTPUT_INTERFACE = 14000; |
| const uint32_t RULE_PRIORITY_PRIVILEGED_LEGACY = 16000; |
| const uint32_t RULE_PRIORITY_LEGACY = 17000; |
| const uint32_t RULE_PRIORITY_IMPLICIT_NETWORK = 18000; |
| const uint32_t RULE_PRIORITY_DEFAULT_NETWORK = 21000; |
| const uint32_t RULE_PRIORITY_DIRECTLY_CONNECTED = 22000; |
| // TODO: Uncomment once we are sure everything works. |
| #if 0 |
| const uint32_t RULE_PRIORITY_UNREACHABLE = 23000; |
| #endif |
| |
| // TODO: These values aren't defined by the Linux kernel, because our UID routing changes are not |
| // upstream (yet?), so we can't just pick them up from kernel headers. When (if?) the changes make |
| // it upstream, we'll remove this and rely on the kernel header values. For now, add a static assert |
| // that will warn us if upstream has given these values some other meaning. |
| const uint16_t FRA_UID_START = 18; |
| const uint16_t FRA_UID_END = 19; |
| static_assert(FRA_UID_START > FRA_MAX, |
| "Android-specific FRA_UID_{START,END} values also assigned in Linux uapi. " |
| "Check that these values match what the kernel does and then update this assertion."); |
| |
| const uint16_t NETLINK_REQUEST_FLAGS = NLM_F_REQUEST | NLM_F_ACK; |
| const uint16_t NETLINK_CREATE_REQUEST_FLAGS = NETLINK_REQUEST_FLAGS | NLM_F_CREATE | NLM_F_EXCL; |
| |
| const sockaddr_nl NETLINK_ADDRESS = {AF_NETLINK, 0, 0, 0}; |
| |
| const uint8_t AF_FAMILIES[] = {AF_INET, AF_INET6}; |
| |
| const char* const IP_VERSIONS[] = {"-4", "-6"}; |
| |
| // Avoids "non-constant-expression cannot be narrowed from type 'unsigned int' to 'unsigned short'" |
| // warnings when using RTA_LENGTH(x) inside static initializers (even when x is already uint16_t). |
| constexpr uint16_t U16_RTA_LENGTH(uint16_t x) { |
| return RTA_LENGTH(x); |
| } |
| |
| // These are practically const, but can't be declared so, because they are used to initialize |
| // non-const pointers ("void* iov_base") in iovec arrays. |
| rtattr FRATTR_PRIORITY = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_PRIORITY }; |
| rtattr FRATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_TABLE }; |
| rtattr FRATTR_FWMARK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMARK }; |
| rtattr FRATTR_FWMASK = { U16_RTA_LENGTH(sizeof(uint32_t)), FRA_FWMASK }; |
| rtattr FRATTR_UID_START = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_START }; |
| rtattr FRATTR_UID_END = { U16_RTA_LENGTH(sizeof(uid_t)), FRA_UID_END }; |
| |
| rtattr RTATTR_TABLE = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_TABLE }; |
| rtattr RTATTR_OIF = { U16_RTA_LENGTH(sizeof(uint32_t)), RTA_OIF }; |
| |
| uint8_t PADDING_BUFFER[RTA_ALIGNTO] = {0, 0, 0, 0}; |
| |
| // END CONSTANTS ---------------------------------------------------------------------------------- |
| |
| std::map<std::string, uint32_t> interfaceToIndex; |
| |
| uint32_t getRouteTableForInterface(const char* interface) { |
| uint32_t index = if_nametoindex(interface); |
| if (index) { |
| interfaceToIndex[interface] = index; |
| } else { |
| // If the interface goes away if_nametoindex() will return 0 but we still need to know |
| // the index so we can remove the rules and routes. |
| std::map<std::string, uint32_t>::iterator it = interfaceToIndex.find(interface); |
| if (it != interfaceToIndex.end()) { |
| index = it->second; |
| } |
| } |
| return index ? index + RouteController::ROUTE_TABLE_OFFSET_FROM_INDEX : 0; |
| } |
| |
| // Sends a netlink request and expects an ack. |
| // |iov| is an array of struct iovec that contains the netlink message payload. |
| // The netlink header is generated by this function based on |action| and |flags|. |
| // Returns -errno if there was an error or if the kernel reported an error. |
| WARN_UNUSED_RESULT int sendNetlinkRequest(uint16_t action, uint16_t flags, iovec* iov, int iovlen) { |
| nlmsghdr nlmsg = { |
| .nlmsg_type = action, |
| .nlmsg_flags = flags, |
| }; |
| iov[0].iov_base = &nlmsg; |
| iov[0].iov_len = sizeof(nlmsg); |
| for (int i = 0; i < iovlen; ++i) { |
| nlmsg.nlmsg_len += iov[i].iov_len; |
| } |
| |
| int ret; |
| struct { |
| nlmsghdr msg; |
| nlmsgerr err; |
| } response; |
| |
| int sock = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); |
| if (sock != -1 && |
| connect(sock, reinterpret_cast<const sockaddr*>(&NETLINK_ADDRESS), |
| sizeof(NETLINK_ADDRESS)) != -1 && |
| writev(sock, iov, iovlen) != -1 && |
| (ret = recv(sock, &response, sizeof(response), 0)) != -1) { |
| if (ret == sizeof(response)) { |
| ret = response.err.error; // Netlink errors are negative errno. |
| if (ret) { |
| ALOGE("netlink response contains error (%s)", strerror(-ret)); |
| } |
| } else { |
| ALOGE("bad netlink response message size (%d != %zu)", ret, sizeof(response)); |
| ret = -EBADMSG; |
| } |
| } else { |
| ALOGE("netlink socket/connect/writev/recv failed (%s)", strerror(errno)); |
| ret = -errno; |
| } |
| |
| if (sock != -1) { |
| close(sock); |
| } |
| |
| return ret; |
| } |
| |
| // Adds or removes a routing rule for IPv4 and IPv6. |
| // |
| // + If |table| is non-zero, the rule points at the specified routing table. Otherwise, the rule |
| // returns ENETUNREACH. |
| // + If |mask| is non-zero, the rule matches the specified fwmark and mask. Otherwise, |fwmark| is |
| // ignored. |
| // + If |interface| is non-NULL, the rule matches the specified outgoing interface. |
| // |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyIpRule(uint16_t action, uint32_t priority, uint32_t table, |
| uint32_t fwmark, uint32_t mask, const char* interface, |
| uid_t uidStart, uid_t uidEnd) { |
| // Ensure that if you set a bit in the fwmark, it's not being ignored by the mask. |
| if (fwmark & ~mask) { |
| ALOGE("mask 0x%x does not select all the bits set in fwmark 0x%x", mask, fwmark); |
| return -ERANGE; |
| } |
| |
| // The interface name must include exactly one terminating NULL and be properly padded, or older |
| // kernels will refuse to delete rules. |
| uint16_t paddingLength = 0; |
| size_t interfaceLength = 0; |
| char oifname[IFNAMSIZ]; |
| if (interface) { |
| interfaceLength = strlcpy(oifname, interface, IFNAMSIZ) + 1; |
| if (interfaceLength > IFNAMSIZ) { |
| ALOGE("interface name too long (%zu > %u)", interfaceLength, IFNAMSIZ); |
| return -ENAMETOOLONG; |
| } |
| paddingLength = RTA_SPACE(interfaceLength) - RTA_LENGTH(interfaceLength); |
| } |
| |
| // Either both start and end UID must be specified, or neither. |
| if ((uidStart == INVALID_UID) != (uidEnd == INVALID_UID)) { |
| ALOGE("incompatible start and end UIDs (%u vs %u)", uidStart, uidEnd); |
| return -EUSERS; |
| } |
| bool isUidRule = (uidStart != INVALID_UID); |
| |
| // Assemble a rule request and put it in an array of iovec structures. |
| fib_rule_hdr rule = { |
| .action = static_cast<uint8_t>(table ? FR_ACT_TO_TBL : FR_ACT_UNREACHABLE), |
| }; |
| |
| rtattr fraOifname = { U16_RTA_LENGTH(interfaceLength), FRA_OIFNAME }; |
| |
| iovec iov[] = { |
| { NULL, 0 }, |
| { &rule, sizeof(rule) }, |
| { &FRATTR_PRIORITY, sizeof(FRATTR_PRIORITY) }, |
| { &priority, sizeof(priority) }, |
| { &FRATTR_TABLE, table ? sizeof(FRATTR_TABLE) : 0 }, |
| { &table, table ? sizeof(table) : 0 }, |
| { &FRATTR_FWMARK, mask ? sizeof(FRATTR_FWMARK) : 0 }, |
| { &fwmark, mask ? sizeof(fwmark) : 0 }, |
| { &FRATTR_FWMASK, mask ? sizeof(FRATTR_FWMASK) : 0 }, |
| { &mask, mask ? sizeof(mask) : 0 }, |
| { &FRATTR_UID_START, isUidRule ? sizeof(FRATTR_UID_START) : 0 }, |
| { &uidStart, isUidRule ? sizeof(uidStart) : 0 }, |
| { &FRATTR_UID_END, isUidRule ? sizeof(FRATTR_UID_END) : 0 }, |
| { &uidEnd, isUidRule ? sizeof(uidEnd) : 0 }, |
| { &fraOifname, interface ? sizeof(fraOifname) : 0 }, |
| { oifname, interfaceLength }, |
| { PADDING_BUFFER, paddingLength }, |
| }; |
| |
| uint16_t flags = (action == RTM_NEWRULE) ? NETLINK_CREATE_REQUEST_FLAGS : NETLINK_REQUEST_FLAGS; |
| for (size_t i = 0; i < ARRAY_SIZE(AF_FAMILIES); ++i) { |
| rule.family = AF_FAMILIES[i]; |
| if (int ret = sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov))) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| // Adds or deletes an IPv4 or IPv6 route. |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyIpRoute(uint16_t action, uint32_t table, const char* interface, |
| const char* destination, const char* nexthop) { |
| // At least the destination must be non-null. |
| if (!destination) { |
| ALOGE("null destination"); |
| return -EFAULT; |
| } |
| |
| // Parse the prefix. |
| uint8_t rawAddress[sizeof(in6_addr)]; |
| uint8_t family; |
| uint8_t prefixLength; |
| int rawLength = parsePrefix(destination, &family, rawAddress, sizeof(rawAddress), |
| &prefixLength); |
| if (rawLength < 0) { |
| ALOGE("parsePrefix failed for destination %s (%s)", destination, strerror(-rawLength)); |
| return rawLength; |
| } |
| |
| if (static_cast<size_t>(rawLength) > sizeof(rawAddress)) { |
| ALOGE("impossible! address too long (%d vs %zu)", rawLength, sizeof(rawAddress)); |
| return -ENOBUFS; // Cannot happen; parsePrefix only supports IPv4 and IPv6. |
| } |
| |
| // If an interface was specified, find the ifindex. |
| uint32_t ifindex; |
| if (interface) { |
| ifindex = if_nametoindex(interface); |
| if (!ifindex) { |
| ALOGE("cannot find interface %s", interface); |
| return -ENODEV; |
| } |
| } |
| |
| // If a nexthop was specified, parse it as the same family as the prefix. |
| uint8_t rawNexthop[sizeof(in6_addr)]; |
| if (nexthop && inet_pton(family, nexthop, rawNexthop) <= 0) { |
| ALOGE("inet_pton failed for nexthop %s", nexthop); |
| return -EINVAL; |
| } |
| |
| // Assemble a rtmsg and put it in an array of iovec structures. |
| rtmsg route = { |
| .rtm_protocol = RTPROT_STATIC, |
| .rtm_type = RTN_UNICAST, |
| .rtm_family = family, |
| .rtm_dst_len = prefixLength, |
| }; |
| |
| rtattr rtaDst = { U16_RTA_LENGTH(rawLength), RTA_DST }; |
| rtattr rtaGateway = { U16_RTA_LENGTH(rawLength), RTA_GATEWAY }; |
| |
| iovec iov[] = { |
| { NULL, 0 }, |
| { &route, sizeof(route) }, |
| { &RTATTR_TABLE, sizeof(RTATTR_TABLE) }, |
| { &table, sizeof(table) }, |
| { &rtaDst, sizeof(rtaDst) }, |
| { rawAddress, static_cast<size_t>(rawLength) }, |
| { &RTATTR_OIF, interface ? sizeof(RTATTR_OIF) : 0 }, |
| { &ifindex, interface ? sizeof(ifindex) : 0 }, |
| { &rtaGateway, nexthop ? sizeof(rtaGateway) : 0 }, |
| { rawNexthop, nexthop ? static_cast<size_t>(rawLength) : 0 }, |
| }; |
| |
| uint16_t flags = (action == RTM_NEWROUTE) ? NETLINK_CREATE_REQUEST_FLAGS : |
| NETLINK_REQUEST_FLAGS; |
| return sendNetlinkRequest(action, flags, iov, ARRAY_SIZE(iov)); |
| } |
| |
| WARN_UNUSED_RESULT int modifyIncomingPacketMark(unsigned netId, const char* interface, bool add) { |
| // An iptables rule to mark incoming packets on a network with the netId of the network. |
| // |
| // This is so that the kernel can: |
| // + Use the right fwmark for (and thus correctly route) replies (e.g.: TCP RST, ICMP errors, |
| // ping replies, SYN-ACKs, etc). |
| // + Mark sockets that accept connections from this interface so that the connection stays on |
| // the same interface. |
| char markString[UINT32_HEX_STRLEN]; |
| snprintf(markString, sizeof(markString), "0x%x", netId); |
| if (execIptables(V4V6, "-t", "mangle", add ? "-A" : "-D", "INPUT", "-i", interface, "-j", |
| "MARK", "--set-mark", markString, NULL)) { |
| ALOGE("failed to change iptables rule that sets incoming packet mark"); |
| return -EREMOTEIO; |
| } |
| return 0; |
| } |
| |
| // A rule to let UID 0 (as a proxy for the kernel) access the routes on a given network. |
| WARN_UNUSED_RESULT int modifyKernelAccessRule(uint16_t action, unsigned netId, uint32_t priority, |
| uint32_t table) { |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| return modifyIpRule(action, priority, table, fwmark.intValue, mask.intValue, NULL, 0, 0); |
| } |
| |
| WARN_UNUSED_RESULT int modifyPerNetworkRules(unsigned netId, const char* interface, uint32_t table, |
| Permission permission, uid_t uidStart, uid_t uidEnd, |
| bool add, bool modifyInterfaceBasedRules) { |
| if (!table) { |
| table = getRouteTableForInterface(interface); |
| if (!table) { |
| ALOGE("cannot find interface %s", interface); |
| return -ESRCH; |
| } |
| } |
| |
| uint16_t action = add ? RTM_NEWRULE : RTM_DELRULE; |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| // A rule to route traffic based on a chosen outgoing interface. |
| // |
| // Supports apps that use SO_BINDTODEVICE or IP_PKTINFO options and the kernel that already |
| // knows the outgoing interface (typically for link-local communications). |
| fwmark.permission = permission; |
| mask.permission = permission; |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_OUTPUT_INTERFACE, table, fwmark.intValue, |
| mask.intValue, interface, uidStart, uidEnd)) { |
| return ret; |
| } |
| |
| // A rule to route traffic based on the chosen network. |
| // |
| // This is for sockets that have not explicitly requested a particular network, but have been |
| // bound to one when they called connect(). This ensures that sockets connected on a particular |
| // network stay on that network even if the default network changes. |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_IMPLICIT_NETWORK, table, fwmark.intValue, |
| mask.intValue, NULL, uidStart, uidEnd)) { |
| return ret; |
| } |
| |
| // A rule to route traffic based on an explicitly chosen network. |
| // |
| // Supports apps that use the multinetwork APIs to restrict their traffic to a network. |
| // |
| // Even though we check permissions at the time we set a netId into the fwmark of a socket, we |
| // still need to check it again in the rules here, because a network's permissions may have been |
| // updated via modifyNetworkPermission(). |
| fwmark.explicitlySelected = true; |
| mask.explicitlySelected = true; |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_EXPLICIT_NETWORK, table, fwmark.intValue, |
| mask.intValue, NULL, uidStart, uidEnd)) { |
| return ret; |
| } |
| |
| if (permission != PERMISSION_NONE) { |
| if (int ret = modifyKernelAccessRule(action, netId, RULE_PRIORITY_IMPLICIT_NETWORK, |
| table)) { |
| return ret; |
| } |
| } |
| |
| if (modifyInterfaceBasedRules) { |
| if (int ret = modifyIncomingPacketMark(netId, interface, add)) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| // Adds or removes rules for VPNs that affect UIDs in |uidRanges|. If |modifyInterfaceBasedRules| |
| // is true, also modifies the rules that are based only on the |interface| and not on |uidRanges|. |
| // When adding or removing an interface to the VPN, set it to true. When adding or removing UIDs |
| // without changing the VPN's interfaces, set it to false. |
| WARN_UNUSED_RESULT int modifyVpnRules(unsigned netId, const char* interface, |
| const UidRanges& uidRanges, bool add, |
| bool modifyInterfaceBasedRules) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (!table) { |
| ALOGE("cannot find interface %s", interface); |
| return -ESRCH; |
| } |
| |
| uint16_t action = add ? RTM_NEWRULE : RTM_DELRULE; |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.protectedFromVpn = false; |
| mask.protectedFromVpn = true; |
| |
| for (const std::pair<uid_t, uid_t>& range : uidRanges.getRanges()) { |
| if (int ret = modifyPerNetworkRules(netId, interface, table, PERMISSION_NONE, range.first, |
| range.second, add, false)) { |
| return ret; |
| } |
| |
| // A rule to route all traffic from a given set of UIDs to go over the VPN. |
| // |
| // Notice that this rule doesn't use the netId. I.e., no matter what netId the user's socket |
| // may have, if they are subject to this VPN, their traffic has to go through it. Allows the |
| // traffic to bypass the VPN if the protectedFromVpn bit is set. |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_SECURE_VPN, table, fwmark.intValue, |
| mask.intValue, NULL, range.first, range.second)) { |
| return ret; |
| } |
| } |
| |
| if (modifyInterfaceBasedRules) { |
| if (int ret = modifyKernelAccessRule(action, netId, RULE_PRIORITY_IMPLICIT_NETWORK, |
| table)) { |
| return ret; |
| } |
| |
| if (int ret = modifyIncomingPacketMark(netId, interface, add)) { |
| return ret; |
| } |
| |
| // A rule to allow privileged apps to send traffic over this VPN even if they are not part |
| // of the target set of UIDs. |
| // |
| // This is needed for DnsProxyListener to correctly resolve a request for a user who is in |
| // the target set, but where the DnsProxyListener itself is not. |
| fwmark.protectedFromVpn = false; |
| mask.protectedFromVpn = false; |
| |
| fwmark.netId = netId; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.permission = PERMISSION_CONNECTIVITY_INTERNAL; |
| mask.permission = PERMISSION_CONNECTIVITY_INTERNAL; |
| |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_SECURE_VPN, table, fwmark.intValue, |
| mask.intValue, NULL, INVALID_UID, INVALID_UID)) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| WARN_UNUSED_RESULT int modifyDefaultNetworkRules(uint16_t action, const char* interface, |
| Permission permission) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (!table) { |
| ALOGE("cannot find interface %s", interface); |
| return -ESRCH; |
| } |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| fwmark.netId = 0; |
| mask.netId = FWMARK_NET_ID_MASK; |
| |
| fwmark.permission = permission; |
| mask.permission = permission; |
| |
| if (int ret = modifyIpRule(action, RULE_PRIORITY_DEFAULT_NETWORK, table, fwmark.intValue, |
| mask.intValue, NULL, INVALID_UID, INVALID_UID)) { |
| return ret; |
| } |
| |
| if (permission != PERMISSION_NONE) { |
| if (int ret = modifyKernelAccessRule(action, 0, RULE_PRIORITY_DEFAULT_NETWORK, table)) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| // Adds or removes an IPv4 or IPv6 route to the specified table and, if it's a directly-connected |
| // route, to the main table as well. |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int modifyRoute(uint16_t action, const char* interface, const char* destination, |
| const char* nexthop, RouteController::TableType tableType) { |
| uint32_t table = 0; |
| switch (tableType) { |
| case RouteController::INTERFACE: { |
| table = getRouteTableForInterface(interface); |
| break; |
| } |
| case RouteController::LEGACY: { |
| table = RouteController::ROUTE_TABLE_LEGACY; |
| break; |
| } |
| case RouteController::PRIVILEGED_LEGACY: { |
| table = RouteController::ROUTE_TABLE_PRIVILEGED_LEGACY; |
| break; |
| } |
| } |
| if (!table) { |
| ALOGE("cannot find table for interface %s and tableType %d", interface, tableType); |
| return -ESRCH; |
| } |
| |
| int ret = modifyIpRoute(action, table, interface, destination, nexthop); |
| // We allow apps to call requestRouteToHost() multiple times with the same route, so ignore |
| // EEXIST failures when adding routes to legacy tables. |
| if (ret != 0 && !(action == RTM_NEWROUTE && ret == -EEXIST && |
| (tableType == RouteController::LEGACY || |
| tableType == RouteController::PRIVILEGED_LEGACY))) { |
| return ret; |
| } |
| |
| // If there's no nexthop, this is a directly connected route. Add it to the main table also, to |
| // let the kernel find it when validating nexthops when global routes are added. |
| if (!nexthop) { |
| ret = modifyIpRoute(action, RT_TABLE_MAIN, interface, destination, NULL); |
| // A failure with action == ADD && errno == EEXIST means that the route already exists in |
| // the main table, perhaps because the kernel added it automatically as part of adding the |
| // IP address to the interface. Ignore this, but complain about everything else. |
| if (ret && !(action == RTM_NEWROUTE && ret == -EEXIST)) { |
| return ret; |
| } |
| } |
| |
| return 0; |
| } |
| |
| // Returns 0 on success or negative errno on failure. |
| WARN_UNUSED_RESULT int flushRoutes(const char* interface) { |
| uint32_t table = getRouteTableForInterface(interface); |
| if (!table) { |
| ALOGE("cannot find interface %s", interface); |
| return -ESRCH; |
| } |
| interfaceToIndex.erase(interface); |
| |
| char tableString[UINT32_STRLEN]; |
| snprintf(tableString, sizeof(tableString), "%u", table); |
| |
| for (size_t i = 0; i < ARRAY_SIZE(IP_VERSIONS); ++i) { |
| const char* argv[] = { |
| IP_PATH, |
| IP_VERSIONS[i], |
| "route", |
| "flush", |
| "table", |
| tableString, |
| }; |
| if (android_fork_execvp(ARRAY_SIZE(argv), const_cast<char**>(argv), NULL, false, false)) { |
| ALOGE("failed to flush routes"); |
| return -EREMOTEIO; |
| } |
| } |
| |
| return 0; |
| } |
| |
| } // namespace |
| |
| int RouteController::Init() { |
| // Add a new rule to look up the 'main' table, with the same selectors as the "default network" |
| // rule, but with a lower priority. Since the default network rule points to a table with a |
| // default route, the rule we're adding will never be used for normal routing lookups. However, |
| // the kernel may fall-through to it to find directly-connected routes when it validates that a |
| // nexthop (in a route being added) is reachable. |
| if (int ret = modifyKernelAccessRule(RTM_NEWRULE, 0, RULE_PRIORITY_DIRECTLY_CONNECTED, |
| RT_TABLE_MAIN)) { |
| return ret; |
| } |
| |
| Fwmark fwmark; |
| Fwmark mask; |
| |
| // Add rules to allow legacy routes to override the default network. |
| fwmark.explicitlySelected = false; |
| mask.explicitlySelected = true; |
| |
| if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_PRIVILEGED_LEGACY, |
| RouteController::ROUTE_TABLE_PRIVILEGED_LEGACY, fwmark.intValue, |
| mask.intValue, NULL, INVALID_UID, INVALID_UID)) { |
| return ret; |
| } |
| |
| if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_LEGACY, |
| RouteController::ROUTE_TABLE_LEGACY, fwmark.intValue, mask.intValue, |
| NULL, INVALID_UID, INVALID_UID)) { |
| return ret; |
| } |
| |
| // Add a rule to allow legacy routes from privileged apps to override VPNs. |
| fwmark.permission = PERMISSION_CONNECTIVITY_INTERNAL; |
| mask.permission = PERMISSION_CONNECTIVITY_INTERNAL; |
| |
| if (int ret = modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_VPN_OVERRIDES, |
| RouteController::ROUTE_TABLE_PRIVILEGED_LEGACY, fwmark.intValue, |
| mask.intValue, NULL, INVALID_UID, INVALID_UID)) { |
| return ret; |
| } |
| |
| // TODO: Uncomment once we are sure everything works. |
| #if 0 |
| // Add a rule to preempt the pre-defined "from all lookup main" rule. Packets that reach this |
| // rule will be null-routed, and won't fall-through to the main table. |
| return modifyIpRule(RTM_NEWRULE, RULE_PRIORITY_UNREACHABLE, 0, 0, 0, NULL, INVALID_UID, |
| INVALID_UID); |
| #else |
| return 0; |
| #endif |
| } |
| |
| int RouteController::addInterfaceToNetwork(unsigned netId, const char* interface, |
| Permission permission) { |
| return modifyPerNetworkRules(netId, interface, 0, permission, INVALID_UID, INVALID_UID, true, |
| true); |
| } |
| |
| int RouteController::removeInterfaceFromNetwork(unsigned netId, const char* interface, |
| Permission permission) { |
| if (int ret = modifyPerNetworkRules(netId, interface, 0, permission, INVALID_UID, INVALID_UID, |
| false, true)) { |
| return ret; |
| } |
| return flushRoutes(interface); |
| } |
| |
| int RouteController::addInterfaceToVpn(unsigned netId, const char* interface, |
| const UidRanges& uidRanges) { |
| return modifyVpnRules(netId, interface, uidRanges, true, true); |
| } |
| |
| int RouteController::removeInterfaceFromVpn(unsigned netId, const char* interface, |
| const UidRanges& uidRanges) { |
| if (int ret = modifyVpnRules(netId, interface, uidRanges, false, true)) { |
| return ret; |
| } |
| return flushRoutes(interface); |
| } |
| |
| int RouteController::modifyNetworkPermission(unsigned netId, const char* interface, |
| Permission oldPermission, Permission newPermission) { |
| // Add the new rules before deleting the old ones, to avoid race conditions. |
| if (int ret = modifyPerNetworkRules(netId, interface, 0, newPermission, INVALID_UID, |
| INVALID_UID, true, false)) { |
| return ret; |
| } |
| return modifyPerNetworkRules(netId, interface, 0, oldPermission, INVALID_UID, INVALID_UID, |
| false, false); |
| } |
| |
| int RouteController::addUsersToVpn(unsigned netId, const char* interface, |
| const UidRanges& uidRanges) { |
| return modifyVpnRules(netId, interface, uidRanges, true, false); |
| } |
| |
| int RouteController::removeUsersFromVpn(unsigned netId, const char* interface, |
| const UidRanges& uidRanges) { |
| return modifyVpnRules(netId, interface, uidRanges, false, false); |
| } |
| |
| int RouteController::addToDefaultNetwork(const char* interface, Permission permission) { |
| return modifyDefaultNetworkRules(RTM_NEWRULE, interface, permission); |
| } |
| |
| int RouteController::removeFromDefaultNetwork(const char* interface, Permission permission) { |
| return modifyDefaultNetworkRules(RTM_DELRULE, interface, permission); |
| } |
| |
| int RouteController::addRoute(const char* interface, const char* destination, const char* nexthop, |
| TableType tableType) { |
| return modifyRoute(RTM_NEWROUTE, interface, destination, nexthop, tableType); |
| } |
| |
| int RouteController::removeRoute(const char* interface, const char* destination, |
| const char* nexthop, TableType tableType) { |
| return modifyRoute(RTM_DELROUTE, interface, destination, nexthop, tableType); |
| } |