| /* |
| * Copyright (C) 2008 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 <stdlib.h> |
| #include <errno.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| #include <fcntl.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| |
| #define LOG_TAG "NatController" |
| #include <cutils/log.h> |
| |
| #include "NatController.h" |
| |
| extern "C" int logwrap(int argc, const char **argv, int background); |
| |
| static char IPTABLES_PATH[] = "/system/bin/iptables"; |
| |
| NatController::NatController() { |
| natCount = 0; |
| } |
| |
| NatController::~NatController() { |
| } |
| |
| int NatController::runIptablesCmd(const char *cmd) { |
| char buffer[255]; |
| |
| strncpy(buffer, cmd, sizeof(buffer)-1); |
| |
| const char *args[16]; |
| char *next = buffer; |
| char *tmp; |
| |
| args[0] = IPTABLES_PATH; |
| args[1] = "--verbose"; |
| int i = 2; |
| |
| while ((tmp = strsep(&next, " "))) { |
| args[i++] = tmp; |
| if (i == 16) { |
| LOGE("iptables argument overflow"); |
| errno = E2BIG; |
| return -1; |
| } |
| } |
| args[i] = NULL; |
| |
| return logwrap(i, args, 0); |
| } |
| |
| int NatController::setDefaults() { |
| |
| if (runIptablesCmd("-P INPUT ACCEPT")) |
| return -1; |
| if (runIptablesCmd("-F INPUT")) |
| return -1; |
| if (runIptablesCmd("-P OUTPUT ACCEPT")) |
| return -1; |
| if (runIptablesCmd("-F OUTPUT")) |
| return -1; |
| if (runIptablesCmd("-P FORWARD DROP")) |
| return -1; |
| if (runIptablesCmd("-F FORWARD")) |
| return -1; |
| if (runIptablesCmd("-t nat -F")) |
| return -1; |
| return 0; |
| } |
| |
| bool NatController::interfaceExists(const char *iface) { |
| // XXX: STOPSHIP - Implement this |
| return true; |
| } |
| |
| int NatController::doNatCommands(const char *intIface, const char *extIface, bool add) { |
| char cmd[255]; |
| |
| // handle decrement to 0 case (do reset to defaults) and erroneous dec below 0 |
| if (add == false) { |
| if (natCount <= 1) { |
| int ret = setDefaults(); |
| if (ret == 0) { |
| natCount=0; |
| } |
| return ret; |
| } |
| } |
| |
| if (!interfaceExists(intIface) || !interfaceExists (extIface)) { |
| LOGE("Invalid interface specified"); |
| errno = ENODEV; |
| return -1; |
| } |
| |
| snprintf(cmd, sizeof(cmd), |
| "-%s FORWARD -i %s -o %s -m state --state ESTABLISHED,RELATED -j ACCEPT", |
| (add ? "A" : "D"), |
| extIface, intIface); |
| if (runIptablesCmd(cmd)) { |
| return -1; |
| } |
| |
| snprintf(cmd, sizeof(cmd), "-%s FORWARD -i %s -o %s -j ACCEPT", (add ? "A" : "D"), |
| intIface, extIface); |
| if (runIptablesCmd(cmd)) { |
| // unwind what's been done, but don't care about success - what more could we do? |
| snprintf(cmd, sizeof(cmd), |
| "-%s FORWARD -i %s -o %s -m state --state ESTABLISHED,RELATED -j ACCEPT", |
| (!add ? "A" : "D"), |
| extIface, intIface); |
| return -1; |
| } |
| |
| // add this if we are the first added nat |
| if (add && natCount == 0) { |
| snprintf(cmd, sizeof(cmd), "-t nat -A POSTROUTING -o %s -j MASQUERADE", extIface); |
| if (runIptablesCmd(cmd)) { |
| // unwind what's been done, but don't care about success - what more could we do? |
| setDefaults();; |
| return -1; |
| } |
| } |
| |
| if (add) { |
| natCount++; |
| } else { |
| natCount--; |
| } |
| return 0; |
| } |
| |
| int NatController::enableNat(const char *intIface, const char *extIface) { |
| return doNatCommands(intIface, extIface, true); |
| } |
| |
| int NatController::disableNat(const char *intIface, const char *extIface) { |
| return doNatCommands(intIface, extIface, false); |
| } |