2 * Copyright (C) 2008 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 // #define LOG_NDEBUG 0
21 #include <sys/socket.h>
24 #include <netinet/in.h>
25 #include <arpa/inet.h>
27 #include <cutils/properties.h>
29 #define LOG_TAG "NatController"
30 #include <cutils/log.h>
32 #include "NatController.h"
33 #include "SecondaryTableController.h"
34 #include "NetdConstants.h"
36 extern "C" int system_nosh(const char *command);
38 NatController::NatController(SecondaryTableController *ctrl) {
39 secondaryTableCtrl = ctrl;
45 NatController::~NatController() {
48 int NatController::runCmd(const char *path, const char *cmd) {
50 size_t len = strnlen(cmd, 255);
54 ALOGE("command too long");
59 asprintf(&buffer, "%s %s", path, cmd);
60 res = system_nosh(buffer);
61 ALOGV("runCmd() buffer='%s' res=%d", buffer, res);
66 int NatController::setupIptablesHooks() {
67 if (runCmd(IPTABLES_PATH, "-P INPUT ACCEPT"))
69 if (runCmd(IPTABLES_PATH, "-P OUTPUT ACCEPT"))
71 if (runCmd(IPTABLES_PATH, "-P FORWARD ACCEPT"))
74 // Order is important!
75 // -D to delete any pre-existing jump rule, to prevent dupes (no-op if doesn't exist)
76 // -F to flush the chain (no-op if doesn't exist).
77 // -N to create the chain (no-op if already exist).
79 runCmd(IPTABLES_PATH, "-D FORWARD -j natctrl_FORWARD");
80 runCmd(IPTABLES_PATH, "-F natctrl_FORWARD");
81 runCmd(IPTABLES_PATH, "-N natctrl_FORWARD");
82 if (runCmd(IPTABLES_PATH, "-A FORWARD -j natctrl_FORWARD"))
85 runCmd(IPTABLES_PATH, "-t nat -D POSTROUTING -j natctrl_nat_POSTROUTING");
86 runCmd(IPTABLES_PATH, "-t nat -F natctrl_nat_POSTROUTING");
87 runCmd(IPTABLES_PATH, "-t nat -N natctrl_nat_POSTROUTING");
88 if (runCmd(IPTABLES_PATH, "-t nat -A POSTROUTING -j natctrl_nat_POSTROUTING"))
94 int NatController::setDefaults() {
95 if (runCmd(IPTABLES_PATH, "-F natctrl_FORWARD"))
97 if (runCmd(IPTABLES_PATH, "-t nat -F natctrl_nat_POSTROUTING"))
100 runCmd(IP_PATH, "rule flush");
101 runCmd(IP_PATH, "-6 rule flush");
102 runCmd(IP_PATH, "rule add from all lookup default prio 32767");
103 runCmd(IP_PATH, "rule add from all lookup main prio 32766");
104 runCmd(IP_PATH, "-6 rule add from all lookup default prio 32767");
105 runCmd(IP_PATH, "-6 rule add from all lookup main prio 32766");
106 runCmd(IP_PATH, "route flush cache");
113 bool NatController::checkInterface(const char *iface) {
114 if (strlen(iface) > IFNAMSIZ) return false;
119 // nat enable intface extface addrcnt nated-ipaddr/prelength
120 int NatController::enableNat(const int argc, char **argv) {
123 int addrCount = atoi(argv[4]);
125 const char *intIface = argv[2];
126 const char *extIface = argv[3];
129 if (!checkInterface(intIface) || !checkInterface(extIface)) {
130 ALOGE("Invalid interface specified");
135 if (argc < 5 + addrCount) {
136 ALOGE("Missing Argument");
141 tableNumber = secondaryTableCtrl->findTableNumber(extIface);
142 if (tableNumber != -1) {
143 for(i = 0; i < addrCount; i++) {
144 ret |= secondaryTableCtrl->modifyFromRule(tableNumber, ADD, argv[5+i]);
146 ret |= secondaryTableCtrl->modifyLocalRoute(tableNumber, ADD, intIface, argv[5+i]);
148 runCmd(IP_PATH, "route flush cache");
151 if (ret != 0 || setForwardRules(true, intIface, extIface) != 0) {
152 if (tableNumber != -1) {
153 for (i = 0; i < addrCount; i++) {
154 secondaryTableCtrl->modifyLocalRoute(tableNumber, DEL, intIface, argv[5+i]);
156 secondaryTableCtrl->modifyFromRule(tableNumber, DEL, argv[5+i]);
158 runCmd(IP_PATH, "route flush cache");
160 ALOGE("Error setting forward rules");
165 /* Always make sure the drop rule is at the end */
166 snprintf(cmd, sizeof(cmd), "-D natctrl_FORWARD -j DROP");
167 runCmd(IPTABLES_PATH, cmd);
168 snprintf(cmd, sizeof(cmd), "-A natctrl_FORWARD -j DROP");
169 runCmd(IPTABLES_PATH, cmd);
173 // add this if we are the first added nat
175 snprintf(cmd, sizeof(cmd), "-t nat -A natctrl_nat_POSTROUTING -o %s -j MASQUERADE", extIface);
176 if (runCmd(IPTABLES_PATH, cmd)) {
177 ALOGE("Error seting postroute rule: %s", cmd);
178 // unwind what's been done, but don't care about success - what more could we do?
179 for (i = 0; i < addrCount; i++) {
180 secondaryTableCtrl->modifyLocalRoute(tableNumber, DEL, intIface, argv[5+i]);
182 secondaryTableCtrl->modifyFromRule(tableNumber, DEL, argv[5+i]);
192 int NatController::setForwardRules(bool add, const char *intIface, const char * extIface) {
195 snprintf(cmd, sizeof(cmd),
196 "-%s natctrl_FORWARD -i %s -o %s -m state --state ESTABLISHED,RELATED -j RETURN",
199 if (runCmd(IPTABLES_PATH, cmd) && add) {
203 snprintf(cmd, sizeof(cmd),
204 "-%s natctrl_FORWARD -i %s -o %s -m state --state INVALID -j DROP",
207 if (runCmd(IPTABLES_PATH, cmd) && add) {
208 // bail on error, but only if adding
209 snprintf(cmd, sizeof(cmd),
210 "-%s natctrl_FORWARD -i %s -o %s -m state --state ESTABLISHED,RELATED -j RETURN",
213 runCmd(IPTABLES_PATH, cmd);
217 snprintf(cmd, sizeof(cmd), "-%s natctrl_FORWARD -i %s -o %s -j RETURN", (add ? "A" : "D"),
219 if (runCmd(IPTABLES_PATH, cmd) && add) {
220 // unwind what's been done, but don't care about success - what more could we do?
221 snprintf(cmd, sizeof(cmd),
222 "-%s natctrl_FORWARD -i %s -o %s -m state --state INVALID -j DROP",
225 runCmd(IPTABLES_PATH, cmd);
227 snprintf(cmd, sizeof(cmd),
228 "-%s natctrl_FORWARD -i %s -o %s -m state --state ESTABLISHED,RELATED -j RETURN",
231 runCmd(IPTABLES_PATH, cmd);
235 snprintf(cmd, sizeof(cmd), "-%s natctrl_FORWARD -j DROP", (add ? "A" : "D"),
237 runCmd(IPTABLES_PATH, cmd);
242 // nat disable intface extface
244 // nat enable intface extface addrcnt nated-ipaddr/prelength
245 int NatController::disableNat(const int argc, char **argv) {
248 int addrCount = atoi(argv[4]);
249 const char *intIface = argv[2];
250 const char *extIface = argv[3];
253 if (!checkInterface(intIface) || !checkInterface(extIface)) {
254 ALOGE("Invalid interface specified");
259 if (argc < 5 + addrCount) {
260 ALOGE("Missing Argument");
265 setForwardRules(false, intIface, extIface);
267 tableNumber = secondaryTableCtrl->findTableNumber(extIface);
268 if (tableNumber != -1) {
269 for (i = 0; i < addrCount; i++) {
270 secondaryTableCtrl->modifyLocalRoute(tableNumber, DEL, intIface, argv[5+i]);
272 secondaryTableCtrl->modifyFromRule(tableNumber, DEL, argv[5+i]);
275 runCmd(IP_PATH, "route flush cache");
278 if (--natCount <= 0) {
279 // handle decrement to 0 case (do reset to defaults) and erroneous dec below 0