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];
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        usleep(NAP_TIME * 1000);
77        if (property_get(name, value, NULL)) {
78            if (desired_value == NULL ||
79                    strcmp(value, desired_value) == 0) {
80                return 0;
81            }
82        }
83    }
84    return -1; /* failure */
85}
86
87static int fill_ip_info(const char *interface,
88                     char *ipaddr,
89                     char *gateway,
90                     uint32_t *prefixLength,
91                     char *dns[],
92                     char *server,
93                     uint32_t *lease,
94                     char *vendorInfo,
95                     char *domain,
96                     char *mtu)
97{
98    char prop_name[PROPERTY_KEY_MAX];
99    char prop_value[PROPERTY_VALUE_MAX];
100    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
101    char p2p_interface[MAX_INTERFACE_LENGTH];
102    int x;
103
104    get_p2p_interface_replacement(interface, p2p_interface);
105
106    snprintf(prop_name, sizeof(prop_name), "%s.%s.ipaddress", DHCP_PROP_NAME_PREFIX, p2p_interface);
107    property_get(prop_name, ipaddr, NULL);
108
109    snprintf(prop_name, sizeof(prop_name), "%s.%s.gateway", DHCP_PROP_NAME_PREFIX, p2p_interface);
110    property_get(prop_name, gateway, NULL);
111
112    snprintf(prop_name, sizeof(prop_name), "%s.%s.server", DHCP_PROP_NAME_PREFIX, p2p_interface);
113    property_get(prop_name, server, NULL);
114
115    //TODO: Handle IPv6 when we change system property usage
116    if (gateway[0] == '\0' || strncmp(gateway, "0.0.0.0", 7) == 0) {
117        //DHCP server is our best bet as gateway
118        strncpy(gateway, server, PROPERTY_VALUE_MAX);
119    }
120
121    snprintf(prop_name, sizeof(prop_name), "%s.%s.mask", DHCP_PROP_NAME_PREFIX, p2p_interface);
122    if (property_get(prop_name, prop_value, NULL)) {
123        int p;
124        // this conversion is v4 only, but this dhcp client is v4 only anyway
125        in_addr_t mask = ntohl(inet_addr(prop_value));
126        // Check netmask is a valid IP address.  ntohl gives NONE response (all 1's) for
127        // non 255.255.255.255 inputs.  if we get that value check if it is legit..
128        if (mask == INADDR_NONE && strcmp(prop_value, "255.255.255.255") != 0) {
129            snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
130            return -1;
131        }
132        for (p = 0; p < 32; p++) {
133            if (mask == 0) break;
134            // check for non-contiguous netmask, e.g., 255.254.255.0
135            if ((mask & 0x80000000) == 0) {
136                snprintf(errmsg, sizeof(errmsg), "DHCP gave invalid net mask %s", prop_value);
137                return -1;
138            }
139            mask = mask << 1;
140        }
141        *prefixLength = p;
142    }
143
144    for (x=0; dns[x] != NULL; x++) {
145        snprintf(prop_name, sizeof(prop_name), "%s.%s.dns%d", DHCP_PROP_NAME_PREFIX, p2p_interface, x+1);
146        property_get(prop_name, dns[x], NULL);
147    }
148
149    snprintf(prop_name, sizeof(prop_name), "%s.%s.leasetime", DHCP_PROP_NAME_PREFIX, p2p_interface);
150    if (property_get(prop_name, prop_value, NULL)) {
151        *lease = atol(prop_value);
152    }
153
154    snprintf(prop_name, sizeof(prop_name), "%s.%s.vendorInfo", DHCP_PROP_NAME_PREFIX,
155            p2p_interface);
156    property_get(prop_name, vendorInfo, NULL);
157
158    snprintf(prop_name, sizeof(prop_name), "%s.%s.domain", DHCP_PROP_NAME_PREFIX,
159            p2p_interface);
160    property_get(prop_name, domain, NULL);
161
162    snprintf(prop_name, sizeof(prop_name), "%s.%s.mtu", DHCP_PROP_NAME_PREFIX,
163            p2p_interface);
164    property_get(prop_name, mtu, NULL);
165
166    return 0;
167}
168
169static const char *ipaddr_to_string(in_addr_t addr)
170{
171    struct in_addr in_addr;
172
173    in_addr.s_addr = addr;
174    return inet_ntoa(in_addr);
175}
176
177/*
178 * Start the dhcp client daemon, and wait for it to finish
179 * configuring the interface.
180 *
181 * The device init.rc file needs a corresponding entry for this work.
182 *
183 * Example:
184 * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
185 */
186int dhcp_do_request(const char *interface,
187                    char *ipaddr,
188                    char *gateway,
189                    uint32_t *prefixLength,
190                    char *dns[],
191                    char *server,
192                    uint32_t *lease,
193                    char *vendorInfo,
194                    char *domain,
195                    char *mtu)
196{
197    char result_prop_name[PROPERTY_KEY_MAX];
198    char daemon_prop_name[PROPERTY_KEY_MAX];
199    char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
200    char daemon_cmd[PROPERTY_VALUE_MAX * 2 + sizeof(DHCP_CONFIG_PATH)];
201    const char *ctrl_prop = "ctl.start";
202    const char *desired_status = "running";
203    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
204    char p2p_interface[MAX_INTERFACE_LENGTH];
205
206    get_p2p_interface_replacement(interface, p2p_interface);
207
208    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
209            DHCP_PROP_NAME_PREFIX,
210            p2p_interface);
211
212    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
213            DAEMON_PROP_NAME,
214            p2p_interface);
215
216    /* Erase any previous setting of the dhcp result property */
217    property_set(result_prop_name, "");
218
219    /* Start the daemon and wait until it's ready */
220    if (property_get(HOSTNAME_PROP_NAME, prop_value, NULL) && (prop_value[0] != '\0'))
221        snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s -h %s %s", DAEMON_NAME,
222                 p2p_interface, DHCP_CONFIG_PATH, prop_value, interface);
223    else
224        snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:-f %s %s", DAEMON_NAME,
225                 p2p_interface, DHCP_CONFIG_PATH, interface);
226    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
227    property_set(ctrl_prop, daemon_cmd);
228    if (wait_for_property(daemon_prop_name, desired_status, 10) < 0) {
229        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for dhcpcd to start");
230        return -1;
231    }
232
233    /* Wait for the daemon to return a result */
234    if (wait_for_property(result_prop_name, NULL, 30) < 0) {
235        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP to finish");
236        return -1;
237    }
238
239    if (!property_get(result_prop_name, prop_value, NULL)) {
240        /* shouldn't ever happen, given the success of wait_for_property() */
241        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
242        return -1;
243    }
244    if (strcmp(prop_value, "ok") == 0) {
245        char dns_prop_name[PROPERTY_KEY_MAX];
246        if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
247                server, lease, vendorInfo, domain, mtu) == -1) {
248            return -1;
249        }
250        return 0;
251    } else {
252        snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
253        return -1;
254    }
255}
256
257/**
258 * Stop the DHCP client daemon.
259 */
260int dhcp_stop(const char *interface)
261{
262    char result_prop_name[PROPERTY_KEY_MAX];
263    char daemon_prop_name[PROPERTY_KEY_MAX];
264    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
265    const char *ctrl_prop = "ctl.stop";
266    const char *desired_status = "stopped";
267
268    char p2p_interface[MAX_INTERFACE_LENGTH];
269
270    get_p2p_interface_replacement(interface, p2p_interface);
271
272    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
273            DHCP_PROP_NAME_PREFIX,
274            p2p_interface);
275
276    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
277            DAEMON_PROP_NAME,
278            p2p_interface);
279
280    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
281
282    /* Stop the daemon and wait until it's reported to be stopped */
283    property_set(ctrl_prop, daemon_cmd);
284    if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
285        return -1;
286    }
287    property_set(result_prop_name, "failed");
288    return 0;
289}
290
291/**
292 * Release the current DHCP client lease.
293 */
294int dhcp_release_lease(const char *interface)
295{
296    char daemon_prop_name[PROPERTY_KEY_MAX];
297    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
298    const char *ctrl_prop = "ctl.stop";
299    const char *desired_status = "stopped";
300
301    char p2p_interface[MAX_INTERFACE_LENGTH];
302
303    get_p2p_interface_replacement(interface, p2p_interface);
304
305    snprintf(daemon_prop_name, sizeof(daemon_prop_name), "%s_%s",
306            DAEMON_PROP_NAME,
307            p2p_interface);
308
309    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s", DAEMON_NAME, p2p_interface);
310
311    /* Stop the daemon and wait until it's reported to be stopped */
312    property_set(ctrl_prop, daemon_cmd);
313    if (wait_for_property(daemon_prop_name, desired_status, 5) < 0) {
314        return -1;
315    }
316    return 0;
317}
318
319char *dhcp_get_errmsg() {
320    return errmsg;
321}
322
323/**
324 * The device init.rc file needs a corresponding entry.
325 *
326 * Example:
327 * service iprenew_<interface> /system/bin/dhcpcd -n
328 *
329 */
330int dhcp_do_request_renew(const char *interface,
331                    char *ipaddr,
332                    char *gateway,
333                    uint32_t *prefixLength,
334                    char *dns[],
335                    char *server,
336                    uint32_t *lease,
337                    char *vendorInfo,
338                    char *domain,
339                    char *mtu)
340{
341    char result_prop_name[PROPERTY_KEY_MAX];
342    char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
343    char daemon_cmd[PROPERTY_VALUE_MAX * 2];
344    const char *ctrl_prop = "ctl.start";
345
346    char p2p_interface[MAX_INTERFACE_LENGTH];
347
348    get_p2p_interface_replacement(interface, p2p_interface);
349
350    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
351            DHCP_PROP_NAME_PREFIX,
352            p2p_interface);
353
354    /* Erase any previous setting of the dhcp result property */
355    property_set(result_prop_name, "");
356
357    /* Start the renew daemon and wait until it's ready */
358    snprintf(daemon_cmd, sizeof(daemon_cmd), "%s_%s:%s", DAEMON_NAME_RENEW,
359            p2p_interface, interface);
360    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
361    property_set(ctrl_prop, daemon_cmd);
362
363    /* Wait for the daemon to return a result */
364    if (wait_for_property(result_prop_name, NULL, 30) < 0) {
365        snprintf(errmsg, sizeof(errmsg), "%s", "Timed out waiting for DHCP Renew to finish");
366        return -1;
367    }
368
369    if (!property_get(result_prop_name, prop_value, NULL)) {
370        /* shouldn't ever happen, given the success of wait_for_property() */
371        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP Renew result property was not set");
372        return -1;
373    }
374    if (strcmp(prop_value, "ok") == 0) {
375        return fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
376                server, lease, vendorInfo, domain, mtu);
377    } else {
378        snprintf(errmsg, sizeof(errmsg), "DHCP Renew result was %s", prop_value);
379        return -1;
380    }
381}
382