SecondaryTableController.cpp revision 4e157a5c901baa020dcc71ca453c31d462272e50 
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        // compare through the final null, hence +1
56        if (strncmp(iface, mInterfaceTable[i], IFNAMSIZ + 1) == 0) {
57            return i;
58        }
59    }
60    return -1;
61}
62
63int SecondaryTableController::addRoute(SocketClient *cli, char *iface, char *dest, int prefix,
64        char *gateway) {
65    int tableIndex = findTableNumber(iface);
66    if (tableIndex == -1) {
67        tableIndex = findTableNumber(""); // look for an empty slot
68        if (tableIndex == -1) {
69            ALOGE("Max number of NATed interfaces reached");
70            errno = ENODEV;
71            cli->sendMsg(ResponseCode::OperationFailed, "Max number NATed", true);
72            return -1;
73        }
74        strncpy(mInterfaceTable[tableIndex], iface, IFNAMSIZ);
75        // Ensure null termination even if truncation happened
76        mInterfaceTable[tableIndex][IFNAMSIZ] = 0;
77    }
78
79    return modifyRoute(cli, ADD, iface, dest, prefix, gateway, tableIndex);
80}
81
82int SecondaryTableController::modifyRoute(SocketClient *cli, const char *action, char *iface,
83        char *dest, int prefix, char *gateway, int tableIndex) {
84    char *cmd;
85
86    if (strcmp("::", gateway) == 0) {
87        //  IP tool doesn't like "::" - the equiv of 0.0.0.0 that it accepts for ipv4
88        asprintf(&cmd, "%s route %s %s/%d dev %s table %d",
89                IP_PATH, action, dest, prefix, iface, tableIndex+BASE_TABLE_NUMBER);
90    } else {
91        asprintf(&cmd, "%s route %s %s/%d via %s dev %s table %d",
92                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
93    }
94
95    if (runAndFree(cli, cmd)) {
96        ALOGE("ip route %s failed: %s route %s %s/%d via %s dev %s table %d", action,
97                IP_PATH, action, dest, prefix, gateway, iface, tableIndex+BASE_TABLE_NUMBER);
98        errno = ENODEV;
99        cli->sendMsg(ResponseCode::OperationFailed, "ip route modification failed", true);
100        return -1;
101    }
102
103    if (strcmp(action, ADD) == 0) {
104        mInterfaceRuleCount[tableIndex]++;
105    } else {
106        if (--mInterfaceRuleCount[tableIndex] < 1) {
107            mInterfaceRuleCount[tableIndex] = 0;
108            mInterfaceTable[tableIndex][0] = 0;
109        }
110    }
111    modifyRuleCount(tableIndex, action);
112    cli->sendMsg(ResponseCode::CommandOkay, "Route modified", false);
113    return 0;
114}
115
116void SecondaryTableController::modifyRuleCount(int tableIndex, const char *action) {
117    if (strcmp(action, ADD) == 0) {
118        mInterfaceRuleCount[tableIndex]++;
119    } else {
120        if (--mInterfaceRuleCount[tableIndex] < 1) {
121            mInterfaceRuleCount[tableIndex] = 0;
122            mInterfaceTable[tableIndex][0] = 0;
123        }
124    }
125}
126
127int SecondaryTableController::verifyTableIndex(int tableIndex) {
128    if ((tableIndex < 0) ||
129            (tableIndex >= INTERFACES_TRACKED) ||
130            (mInterfaceTable[tableIndex][0] == 0)) {
131        return -1;
132    } else {
133        return 0;
134    }
135}
136
137const char *SecondaryTableController::getVersion(const char *addr) {
138    if (strchr(addr, ':') != NULL) {
139        return "-6";
140    } else {
141        return "-4";
142    }
143}
144
145int SecondaryTableController::removeRoute(SocketClient *cli, char *iface, char *dest, int prefix,
146        char *gateway) {
147    int tableIndex = findTableNumber(iface);
148    if (tableIndex == -1) {
149        ALOGE("Interface not found");
150        errno = ENODEV;
151        cli->sendMsg(ResponseCode::OperationFailed, "Interface not found", true);
152        return -1;
153    }
154
155    return modifyRoute(cli, DEL, iface, dest, prefix, gateway, tableIndex);
156}
157
158int SecondaryTableController::modifyFromRule(int tableIndex, const char *action,
159        const char *addr) {
160    char *cmd;
161
162    if (verifyTableIndex(tableIndex)) {
163        return -1;
164    }
165    asprintf(&cmd, "%s %s rule %s from %s table %d", IP_PATH, getVersion(addr),
166            action, addr, tableIndex + BASE_TABLE_NUMBER);
167    if (runAndFree(NULL, cmd)) {
168        return -1;
169    }
170
171    modifyRuleCount(tableIndex, action);
172    return 0;
173}
174
175int SecondaryTableController::modifyLocalRoute(int tableIndex, const char *action,
176        const char *iface, const char *addr) {
177    char *cmd;
178
179    if (verifyTableIndex(tableIndex)) {
180        return -1;
181    }
182
183    modifyRuleCount(tableIndex, action); // some del's will fail as the iface is already gone.
184
185    asprintf(&cmd, "%s route %s %s dev %s table %d", IP_PATH, action, addr, iface,
186            tableIndex+BASE_TABLE_NUMBER);
187    return runAndFree(NULL, cmd);
188}
189
190int SecondaryTableController::runAndFree(SocketClient *cli, char *cmd) {
191    int ret = 0;
192    if (strlen(cmd) >= 255) {
193        if (cli != NULL) {
194            ALOGE("ip command (%s) too long", cmd);
195            errno = E2BIG;
196            cli->sendMsg(ResponseCode::CommandSyntaxError, "Too long", true);
197        }
198        free(cmd);
199        return -1;
200    }
201    ret = system_nosh(cmd);
202    free(cmd);
203    return ret;
204}
205