SecondaryTableController.cpp revision d14fd4f83ffeea4ad1cd559a41f775f6814565cc 
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], IFNAMSIZ) == 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, IFNAMSIZ);
74        // Ensure null termination even if truncation happened
75        mInterfaceTable[tableIndex][IFNAMSIZ] = 0;
76    }
77
78    return modifyRoute(cli, ADD, iface, dest, prefix, gateway, tableIndex);
79}
80
81int SecondaryTableController::modifyRoute(SocketClient *cli, const char *action, char *iface,
82        char *dest, int prefix, char *gateway, int tableIndex) {
83    char *cmd;
84
85    if (strcmp("::", gateway) == 0) {
86        //  IP tool doesn't like "::" - the equiv of 0.0.0.0 that it accepts for ipv4
87        asprintf(&cmd, "%s route %s %s/%d dev %s table %d",
88                IP_PATH, action, dest, prefix, iface, tableIndex+BASE_TABLE_NUMBER);
89    } else {
90        asprintf(&cmd, "%s route %s %s/%d via %s dev %s table %d",
91                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
92    }
93
94    if (runAndFree(cli, cmd)) {
95        ALOGE("ip route %s failed: %s route %s %s/%d via %s dev %s table %d", action,
96                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
97        errno = ENODEV;
98        cli->sendMsg(ResponseCode::OperationFailed, "ip route modification failed", true);
99        return -1;
100    }
101
102    if (strcmp(action, ADD) == 0) {
103        mInterfaceRuleCount[tableIndex]++;
104    } else {
105        if (--mInterfaceRuleCount[tableIndex] < 1) {
106            mInterfaceRuleCount[tableIndex] = 0;
107            mInterfaceTable[tableIndex][0] = 0;
108        }
109    }
110    modifyRuleCount(tableIndex, action);
111    cli->sendMsg(ResponseCode::CommandOkay, "Route modified", false);
112    return 0;
113}
114
115void SecondaryTableController::modifyRuleCount(int tableIndex, const char *action) {
116    if (strcmp(action, ADD) == 0) {
117        mInterfaceRuleCount[tableIndex]++;
118    } else {
119        if (--mInterfaceRuleCount[tableIndex] < 1) {
120            mInterfaceRuleCount[tableIndex] = 0;
121            mInterfaceTable[tableIndex][0] = 0;
122        }
123    }
124}
125
126int SecondaryTableController::verifyTableIndex(int tableIndex) {
127    if ((tableIndex < 0) ||
128            (tableIndex >= INTERFACES_TRACKED) ||
129            (mInterfaceTable[tableIndex][0] == 0)) {
130        return -1;
131    } else {
132        return 0;
133    }
134}
135
136const char *SecondaryTableController::getVersion(const char *addr) {
137    if (strchr(addr, ':') != NULL) {
138        return "-6";
139    } else {
140        return "-4";
141    }
142}
143
144int SecondaryTableController::removeRoute(SocketClient *cli, char *iface, char *dest, int prefix,
145        char *gateway) {
146    int tableIndex = findTableNumber(iface);
147    if (tableIndex == -1) {
148        ALOGE("Interface not found");
149        errno = ENODEV;
150        cli->sendMsg(ResponseCode::OperationFailed, "Interface not found", true);
151        return -1;
152    }
153
154    return modifyRoute(cli, DEL, iface, dest, prefix, gateway, tableIndex);
155}
156
157int SecondaryTableController::modifyFromRule(int tableIndex, const char *action,
158        const char *addr) {
159    char *cmd;
160
161    if (verifyTableIndex(tableIndex)) {
162        return -1;
163    }
164    asprintf(&cmd, "%s %s rule %s from %s table %d", IP_PATH, getVersion(addr),
165            action, addr, tableIndex + BASE_TABLE_NUMBER);
166    if (runAndFree(NULL, cmd)) {
167        return -1;
168    }
169
170    modifyRuleCount(tableIndex, action);
171    return 0;
172}
173
174int SecondaryTableController::modifyLocalRoute(int tableIndex, const char *action,
175        const char *iface, const char *addr) {
176    char *cmd;
177
178    if (verifyTableIndex(tableIndex)) {
179        return -1;
180    }
181
182    modifyRuleCount(tableIndex, action); // some del's will fail as the iface is already gone.
183
184    asprintf(&cmd, "%s route %s %s dev %s table %d", IP_PATH, action, addr, iface,
185            tableIndex+BASE_TABLE_NUMBER);
186    return runAndFree(NULL, cmd);
187}
188
189int SecondaryTableController::runAndFree(SocketClient *cli, char *cmd) {
190    int ret = 0;
191    if (strlen(cmd) >= 255) {
192        if (cli != NULL) {
193            ALOGE("ip command (%s) too long", cmd);
194            errno = E2BIG;
195            cli->sendMsg(ResponseCode::CommandSyntaxError, "Too long", true);
196        }
197        free(cmd);
198        return -1;
199    }
200    ret = system_nosh(cmd);
201    free(cmd);
202    return ret;
203}
204