SecondaryTableController.cpp revision 3c20787d7935c2016e8e3cc49d8f15647c12c41c 
1/*
2 * Copyright (C) 2008 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 <stdlib.h>
18#include <errno.h>
19#include <fcntl.h>
20#include <string.h>
21
22#include <sys/socket.h>
23#include <sys/stat.h>
24#include <sys/types.h>
25#include <sys/wait.h>
26
27#include <netinet/in.h>
28#include <arpa/inet.h>
29
30#define LOG_TAG "SecondaryTablController"
31#include <cutils/log.h>
32#include <cutils/properties.h>
33
34extern "C" int system_nosh(const char *command);
35
36#include "ResponseCode.h"
37#include "SecondaryTableController.h"
38
39static char IP_PATH[] = "/system/bin/ip";
40static char ADD[] = "add";
41static char DEL[] = "del";
42
43SecondaryTableController::SecondaryTableController() {
44    int i;
45    for (i=0; i < INTERFACES_TRACKED; i++) {
46        mInterfaceTable[i][0] = 0;
47        // TODO - use a hashtable or other prebuilt container class
48        mInterfaceRuleCount[i] = 0;
49    }
50}
51
52SecondaryTableController::~SecondaryTableController() {
53}
54
55int SecondaryTableController::findTableNumber(const char *iface) {
56    int i;
57    for (i = 0; i < INTERFACES_TRACKED; i++) {
58        // compare through the final null, hence +1
59        if (strncmp(iface, mInterfaceTable[i], IFNAMSIZ + 1) == 0) {
60            return i;
61        }
62    }
63    return -1;
64}
65
66int SecondaryTableController::addRoute(SocketClient *cli, char *iface, char *dest, int prefix,
67        char *gateway) {
68    int tableIndex = findTableNumber(iface);
69    if (tableIndex == -1) {
70        tableIndex = findTableNumber(""); // look for an empty slot
71        if (tableIndex == -1) {
72            LOGE("Max number of NATed interfaces reached");
73            errno = ENODEV;
74            cli->sendMsg(ResponseCode::OperationFailed, "Max number NATed", true);
75            return -1;
76        }
77        strncpy(mInterfaceTable[tableIndex], iface, IFNAMSIZ);
78        // Ensure null termination even if truncation happened
79        mInterfaceTable[tableIndex][IFNAMSIZ] = 0;
80    }
81
82    return modifyRoute(cli, ADD, iface, dest, prefix, gateway, tableIndex);
83}
84
85int SecondaryTableController::modifyRoute(SocketClient *cli, char *action, char *iface, char *dest,
86        int prefix, char *gateway, int tableIndex) {
87    char *cmd;
88
89    if (strcmp("::", gateway) == 0) {
90        //  IP tool doesn't like "::" - the equiv of 0.0.0.0 that it accepts for ipv4
91        asprintf(&cmd, "%s route %s %s/%d dev %s table %d",
92                IP_PATH, action, dest, prefix, iface, tableIndex+BASE_TABLE_NUMBER);
93    } else {
94        asprintf(&cmd, "%s route %s %s/%d via %s dev %s table %d",
95                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
96    }
97
98    if (runAndFree(cli, cmd)) {
99        LOGE("ip route %s failed: %s route %s %s/%d via %s dev %s table %d", action,
100                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
101        errno = ENODEV;
102        cli->sendMsg(ResponseCode::OperationFailed, "ip route modification failed", true);
103        return -1;
104    }
105
106    if (strcmp(action, ADD) == 0) {
107        mInterfaceRuleCount[tableIndex]++;
108    } else {
109        if (--mInterfaceRuleCount[tableIndex] < 1) {
110            mInterfaceRuleCount[tableIndex] = 0;
111            mInterfaceTable[tableIndex][0] = 0;
112        }
113    }
114    cli->sendMsg(ResponseCode::CommandOkay, "Route modified", false);
115    return 0;
116}
117
118int SecondaryTableController::removeRoute(SocketClient *cli, char *iface, char *dest, int prefix,
119        char *gateway) {
120    int tableIndex = findTableNumber(iface);
121    if (tableIndex == -1) {
122        LOGE("Interface not found");
123        errno = ENODEV;
124        cli->sendMsg(ResponseCode::OperationFailed, "Interface not found", true);
125        return -1;
126    }
127
128    return modifyRoute(cli, DEL, iface, dest, prefix, gateway, tableIndex);
129}
130
131int SecondaryTableController::runAndFree(SocketClient *cli, char *cmd) {
132    int ret = 0;
133    if (strlen(cmd) >= 255) {
134        LOGE("ip command (%s) too long", cmd);
135        errno = E2BIG;
136        cli->sendMsg(ResponseCode::CommandSyntaxError, "Too long", true);
137        free(cmd);
138        return -1;
139    }
140    ret = system_nosh(cmd);
141    free(cmd);
142    return ret;
143}
144