SecondaryTableController.cpp revision c462177bd58e3bf0ac4f618934dae060569e3e0b 
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 "NetdConstants.h"
38#include "SecondaryTableController.h"
39
40SecondaryTableController::SecondaryTableController() {
41    int i;
42    for (i=0; i < INTERFACES_TRACKED; i++) {
43        mInterfaceTable[i][0] = 0;
44        // TODO - use a hashtable or other prebuilt container class
45        mInterfaceRuleCount[i] = 0;
46    }
47}
48
49SecondaryTableController::~SecondaryTableController() {
50}
51
52int SecondaryTableController::findTableNumber(const char *iface) {
53    int i;
54    for (i = 0; i < INTERFACES_TRACKED; i++) {
55        if (strncmp(iface, mInterfaceTable[i], MAX_IFACE_LENGTH) == 0) {
56            return i;
57        }
58    }
59    return -1;
60}
61
62int SecondaryTableController::addRoute(SocketClient *cli, char *iface, char *dest, int prefix,
63        char *gateway) {
64    int tableIndex = findTableNumber(iface);
65    if (tableIndex == -1) {
66        tableIndex = findTableNumber(""); // look for an empty slot
67        if (tableIndex == -1) {
68            ALOGE("Max number of NATed interfaces reached");
69            errno = ENODEV;
70            cli->sendMsg(ResponseCode::OperationFailed, "Max number NATed", true);
71            return -1;
72        }
73        strncpy(mInterfaceTable[tableIndex], iface, MAX_IFACE_LENGTH);
74    }
75
76    return modifyRoute(cli, ADD, iface, dest, prefix, gateway, tableIndex);
77}
78
79int SecondaryTableController::modifyRoute(SocketClient *cli, const char *action, char *iface,
80        char *dest, int prefix, char *gateway, int tableIndex) {
81    char *cmd;
82
83    if (strcmp("::", gateway) == 0) {
84        //  IP tool doesn't like "::" - the equiv of 0.0.0.0 that it accepts for ipv4
85        asprintf(&cmd, "%s route %s %s/%d dev %s table %d",
86                IP_PATH, action, dest, prefix, iface, tableIndex+BASE_TABLE_NUMBER);
87    } else {
88        asprintf(&cmd, "%s route %s %s/%d via %s dev %s table %d",
89                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
90    }
91
92    if (runAndFree(cli, cmd)) {
93        ALOGE("ip route %s failed: %s route %s %s/%d via %s dev %s table %d", action,
94                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
95        errno = ENODEV;
96        cli->sendMsg(ResponseCode::OperationFailed, "ip route modification failed", true);
97        return -1;
98    }
99
100    if (strcmp(action, ADD) == 0) {
101        mInterfaceRuleCount[tableIndex]++;
102    } else {
103        if (--mInterfaceRuleCount[tableIndex] < 1) {
104            mInterfaceRuleCount[tableIndex] = 0;
105            mInterfaceTable[tableIndex][0] = 0;
106        }
107    }
108    modifyRuleCount(tableIndex, action);
109    cli->sendMsg(ResponseCode::CommandOkay, "Route modified", false);
110    return 0;
111}
112
113void SecondaryTableController::modifyRuleCount(int tableIndex, const char *action) {
114    if (strcmp(action, ADD) == 0) {
115        mInterfaceRuleCount[tableIndex]++;
116    } else {
117        if (--mInterfaceRuleCount[tableIndex] < 1) {
118            mInterfaceRuleCount[tableIndex] = 0;
119            mInterfaceTable[tableIndex][0] = 0;
120        }
121    }
122}
123
124int SecondaryTableController::verifyTableIndex(int tableIndex) {
125    if ((tableIndex < 0) ||
126            (tableIndex >= INTERFACES_TRACKED) ||
127            (mInterfaceTable[tableIndex][0] == 0)) {
128        return -1;
129    } else {
130        return 0;
131    }
132}
133
134const char *SecondaryTableController::getVersion(const char *addr) {
135    if (strchr(addr, ':') != NULL) {
136        return "-6";
137    } else {
138        return "-4";
139    }
140}
141
142int SecondaryTableController::removeRoute(SocketClient *cli, char *iface, char *dest, int prefix,
143        char *gateway) {
144    int tableIndex = findTableNumber(iface);
145    if (tableIndex == -1) {
146        ALOGE("Interface not found");
147        errno = ENODEV;
148        cli->sendMsg(ResponseCode::OperationFailed, "Interface not found", true);
149        return -1;
150    }
151
152    return modifyRoute(cli, DEL, iface, dest, prefix, gateway, tableIndex);
153}
154
155int SecondaryTableController::modifyFromRule(int tableIndex, const char *action,
156        const char *addr) {
157    char *cmd;
158
159    if (verifyTableIndex(tableIndex)) {
160        return -1;
161    }
162    asprintf(&cmd, "%s %s rule %s from %s table %d", IP_PATH, getVersion(addr),
163            action, addr, tableIndex + BASE_TABLE_NUMBER);
164    if (runAndFree(NULL, cmd)) {
165        return -1;
166    }
167
168    modifyRuleCount(tableIndex, action);
169    return 0;
170}
171
172int SecondaryTableController::modifyLocalRoute(int tableIndex, const char *action,
173        const char *iface, const char *addr) {
174    char *cmd;
175
176    if (verifyTableIndex(tableIndex)) {
177        return -1;
178    }
179
180    modifyRuleCount(tableIndex, action); // some del's will fail as the iface is already gone.
181
182    asprintf(&cmd, "%s route %s %s dev %s table %d", IP_PATH, action, addr, iface,
183            tableIndex+BASE_TABLE_NUMBER);
184    return runAndFree(NULL, cmd);
185}
186
187int SecondaryTableController::runAndFree(SocketClient *cli, char *cmd) {
188    int ret = 0;
189    if (strlen(cmd) >= 255) {
190        if (cli != NULL) {
191            ALOGE("ip command (%s) too long", cmd);
192            errno = E2BIG;
193            cli->sendMsg(ResponseCode::CommandSyntaxError, "Too long", true);
194        }
195        free(cmd);
196        return -1;
197    }
198    ret = system_nosh(cmd);
199    free(cmd);
200    return ret;
201}
202