1/*
2 * Copyright 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/* Utilities for managing the dhcpcd DHCP client daemon */
18
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <unistd.h>
23#include <arpa/inet.h>
24#include <netinet/in.h>
25
26#include <cutils/properties.h>
27
28static const char DAEMON_NAME[]        = "dhcpcd";
29static const char DAEMON_PROP_NAME[]   = "init.svc.dhcpcd";
30static const char HOSTNAME_PROP_NAME[] = "net.hostname";
31static const char DHCP_PROP_NAME_PREFIX[]  = "dhcp";
32static const char DHCP_CONFIG_PATH[]   = "/system/etc/dhcpcd/dhcpcd.conf";
33static const int NAP_TIME = 200;   /* wait for 200ms at a time */
34                                  /* when polling for property values */
35static const char DAEMON_NAME_RENEW[]  = "iprenew";
36static char errmsg[100] = "\0";
37/* interface length for dhcpcd daemon start (dhcpcd_<interface> as defined in init.rc file)
38 * or for filling up system properties dhcpcd.<interface>.ipaddress, dhcpcd.<interface>.dns1
39 * and other properties on a successful bind
40 */
41#define MAX_INTERFACE_LENGTH 25
42
43/*
44 * P2p interface names increase sequentially p2p-p2p0-1, p2p-p2p0-2.. after
45 * group formation. This does not work well with system properties which can quickly
46 * exhaust or for specifiying a dhcp start target in init which requires
47 * interface to be pre-defined in init.rc file.
48 *
49 * This function returns a common string p2p for all p2p interfaces.
50 */
51void get_p2p_interface_replacement(const char *interface, char *p2p_interface) {
52    /* Use p2p for any interface starting with p2p. */
53    if (strncmp(interface, "p2p",3) == 0) {
54        strncpy(p2p_interface, "p2p", MAX_INTERFACE_LENGTH);
55    } else {
56        strncpy(p2p_interface, interface, MAX_INTERFACE_LENGTH);
57    }
58}
59
60/*
61 * Wait for a system property to be assigned a specified value.
62 * If desired_value is NULL, then just wait for the property to
63 * be created with any value. maxwait is the maximum amount of
64 * time in seconds to wait before giving up.
65 */
66static int wait_for_property(const char *name, const char *desired_value, int maxwait)
67{
68    char value[PROPERTY_VALUE_MAX] = {'\0'};
69    int maxnaps = (maxwait * 1000) / NAP_TIME;
70
71    if (maxnaps < 1) {
72        maxnaps = 1;
73    }
74
75    while (maxnaps-- >= 0) {
76        if (property_get(name, value, NULL)) {
77            if (desired_value == NULL ||
78                    strcmp(value, desired_value) == 0) {
79                return 0;
80            }
81        }
82        if (maxnaps >= 0) {
83            usleep(NAP_TIME * 1000);
84        }
85    }
86    return -1; /* failure */
87}
88
89static int fill_ip_info(const char *interface,
90                     char *ipaddr,
91                     char *gateway,
92                     uint32_t *prefixLength,
93                     char *dns[],
94                     char *server,
95                     uint32_t *lease,
96                     char *vendorInfo,
97                     char *domain,
98                     char *mtu)
99{
100    char prop_name[PROPERTY_KEY_MAX];
101    char prop_value[PROPERTY_VALUE_MAX];
102    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
103    char p2p_interface[MAX_INTERFACE_LENGTH];
104    int x;
105
106    get_p2p_interface_replacement(interface, p2p_interface);
107
108    snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface);
109    property_get(prop_name, ipaddr, NULL);
110
111    snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface);
112    property_get(prop_name, gateway, NULL);
113
114    snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface);
115    property_get(prop_name, server, NULL);
116
117    //TODO: Handle IPv6 when we change system property usage
118    if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) {
119        //DHCP server is our best bet as gateway
120        strncpy(gateway, server, PROPERTY_VALUE_MAX);
121    }
122
123    snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_interface);
124    if (property_get(prop_name, prop_value, NULL)) {
125        int p;
126        // this conversion is v4 only, but this dhcp client is v4 only anyway
127        in_addr_t mask = ntohl(inet_addr(prop_value));
128        // Check netmask is a valid IP address.  ntohl gives NONE response (all 1's) for
129        // non 255.255.255.255 inputs.  if we get that value check if it is legit..
130        if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) {
131            snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
132            return -1;
133        }
134        for (p = 0; p < 32; p++) {
135            if (mask == 0) break;
136            // check for non-contiguous netmask, e.g., 255.254.255.0
137            if ((mask & 0x80000000) == 0) {
138                snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
139                return -1;
140            }
141            mask = mask << 1;
142        }
143        *prefixLength = p;
144    }
145
146    for (x=0; dns[x] != NULL; x++) {
147        snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1);
148        property_get(prop_name, dns[x], NULL);
149    }
150
151    snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface);
152    if (property_get(prop_name, prop_value, NULL)) {
153        *lease = atol(prop_value);
154    }
155
156    snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX,
157            p2p_interface);
158    property_get(prop_name, vendorInfo, NULL);
159
160    snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX,
161            p2p_interface);
162    property_get(prop_name, domain, NULL);
163
164    snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX,
165            p2p_interface);
166    property_get(prop_name, mtu, NULL);
167
168    return 0;
169}
170
171/*
172 * Get any available DHCP results.
173 */
174int dhcp_get_results(const char *interface,
175                     char *ipaddr,
176                     char *gateway,
177                     uint32_t *prefixLength,
178                     char *dns[],
179                     char *server,
180                     uint32_t *lease,
181                     char *vendorInfo,
182                     char *domain,
183                     char *mtu)
184{
185    char result_prop_name[PROPERTY_KEY_MAX];
186    char prop_value[PROPERTY_VALUE_MAX];
187
188    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
189    char p2p_interface[MAX_INTERFACE_LENGTH];
190    get_p2p_interface_replacement(interface, p2p_interface);
191    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
192            DHCP_PROP_NAME_PREFIX,
193            p2p_interface);
194
195    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
196    if (!property_get(result_prop_name, prop_value, NULL)) {
197        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
198        return -1;
199    }
200    if (strcmp(prop_value, "ok") == 0) {
201        if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
202                server, lease, vendorInfo, domain, mtu) == -1) {
203            return -1;
204        }
205        return 0;
206    } else {
207        snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
208        return -1;
209    }
210}
211
212/*
213 * Start the dhcp client daemon, and wait for it to finish
214 * configuring the interface.
215 *
216 * The device init.rc file needs a corresponding entry for this work.
217 *
218 * Example:
219 * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
220 */
221int dhcp_start(const char *interface)
222{
223    char result_prop_name[PROPERTY_KEY_MAX];
224    char daemon_prop_name[PROPERTY_KEY_MAX];
225    char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
226    char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)];
227    const char *ctrl_prop = "ctl.start";
228    const char *desired_status = "running";
229    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
230    char p2p_interface[MAX_INTERFACE_LENGTH];
231
232    get_p2p_interface_replacement(interface, p2p_interface);
233
234    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
235            DHCP_PROP_NAME_PREFIX,
236            p2p_interface);
237
238    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
239            DAEMON_PROP_NAME,
240            p2p_interface);
241
242    /* Erase any previous setting of the dhcp result property */
243    property_set(result_prop_name, "");
244
245    /* Start the daemon and wait until it's ready */
246    if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0'))
247        snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s -h %s %s", DAEMON_NAME,
248                 p2p_interface, DHCP_CONFIG_PATH, prop_value, interface);
249    else
250        snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME,
251                 p2p_interface, DHCP_CONFIG_PATH, interface);
252    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
253    property_set(ctrl_prop, daemon_cmd);
254    if (wait_for_property(daemon_prop_name, desired_status, 10) < 0) {
255        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start");
256        return -1;
257    }
258
259    /* Wait for the daemon to return a result */
260    if (wait_for_property(result_prop_name, NULL, 30) < 0) {
261        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish");
262        return -1;
263    }
264
265    return 0;
266}
267
268/**
269 * Stop the DHCP client daemon.
270 */
271int dhcp_stop(const char *interface)
272{
273    char result_prop_name[PROPERTY_KEY_MAX];
274    char daemon_prop_name[PROPERTY_KEY_MAX];
275    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
276    const char *ctrl_prop = "ctl.stop";
277    const char *desired_status = "stopped";
278
279    char p2p_interface[MAX_INTERFACE_LENGTH];
280
281    get_p2p_interface_replacement(interface, p2p_interface);
282
283    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
284            DHCP_PROP_NAME_PREFIX,
285            p2p_interface);
286
287    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
288            DAEMON_PROP_NAME,
289            p2p_interface);
290
291    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
292
293    /* Stop the daemon and wait until it's reported to be stopped */
294    property_set(ctrl_prop, daemon_cmd);
295    if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
296        return -1;
297    }
298    property_set(result_prop_name, "failed");
299    return 0;
300}
301
302/**
303 * Release the current DHCP client lease.
304 */
305int dhcp_release_lease(const char *interface)
306{
307    char daemon_prop_name[PROPERTY_KEY_MAX];
308    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
309    const char *ctrl_prop = "ctl.stop";
310    const char *desired_status = "stopped";
311
312    char p2p_interface[MAX_INTERFACE_LENGTH];
313
314    get_p2p_interface_replacement(interface, p2p_interface);
315
316    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
317            DAEMON_PROP_NAME,
318            p2p_interface);
319
320    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
321
322    /* Stop the daemon and wait until it's reported to be stopped */
323    property_set(ctrl_prop, daemon_cmd);
324    if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
325        return -1;
326    }
327    return 0;
328}
329
330char *dhcp_get_errmsg() {
331    return errmsg;
332}
333
334/**
335 * The device init.rc file needs a corresponding entry.
336 *
337 * Example:
338 * service iprenew_<interface> /system/bin/dhcpcd -n
339 *
340 */
341int dhcp_start_renew(const char *interface)
342{
343    char result_prop_name[PROPERTY_KEY_MAX];
344    char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
345    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
346    const char *ctrl_prop = "ctl.start";
347
348    char p2p_interface[MAX_INTERFACE_LENGTH];
349
350    get_p2p_interface_replacement(interface, p2p_interface);
351
352    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
353            DHCP_PROP_NAME_PREFIX,
354            p2p_interface);
355
356    /* Erase any previous setting of the dhcp result property */
357    property_set(result_prop_name, "");
358
359    /* Start the renew daemon and wait until it's ready */
360    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW,
361            p2p_interface, interface);
362    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
363    property_set(ctrl_prop, daemon_cmd);
364
365    /* Wait for the daemon to return a result */
366    if (wait_for_property(result_prop_name, NULL, 30) < 0) {
367        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP Renew to finish");
368        return -1;
369    }
370
371    return 0;
372}
373