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"Robert P. J. Day"63fc1a92006-07-02 19:47:05 +00001/* vi: set sw=4 ts=4: */
Denys Vlasenko6b24d532010-03-22 13:42:13 +01002/*
Denys Vlasenko385b4562010-03-26 10:09:34 +01003 * udhcp client
Mike Frysinger7031f622006-05-08 03:20:50 +00004 *
5 * Russ Dill <Russ.Dill@asu.edu> July 2001
6 *
Denys Vlasenko6b24d532010-03-22 13:42:13 +01007 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Mike Frysinger7031f622006-05-08 03:20:50 +000020 */
Denis Vlasenkoaf1c8432007-03-26 13:22:35 +000021#include <syslog.h>
Denis Vlasenko1caca342007-08-02 10:14:29 +000022/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
23#define WANT_PIDFILE 1
Mike Frysinger7031f622006-05-08 03:20:50 +000024#include "common.h"
25#include "dhcpd.h"
26#include "dhcpc.h"
Denis Vlasenko5a3395b2006-11-18 19:51:32 +000027
Dan Fandrichf533ec82011-06-10 05:17:59 +020028#include <netinet/if_ether.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010029#include <linux/filter.h>
Alexey Froloff3c62bba2012-09-17 16:02:44 +020030#include <linux/if_packet.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010031
Denys Vlasenko2017d482011-11-05 01:24:14 +010032/* "struct client_config_t client_config" is in bb_common_bufsiz1 */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +000033
Mike Frysinger7031f622006-05-08 03:20:50 +000034
Keith Younge6bb8d32011-03-07 03:18:46 +010035#if ENABLE_LONG_OPTS
36static const char udhcpc_longopts[] ALIGN1 =
37 "clientid-none\0" No_argument "C"
38 "vendorclass\0" Required_argument "V"
39 "hostname\0" Required_argument "H"
40 "fqdn\0" Required_argument "F"
41 "interface\0" Required_argument "i"
42 "now\0" No_argument "n"
43 "pidfile\0" Required_argument "p"
44 "quit\0" No_argument "q"
45 "release\0" No_argument "R"
46 "request\0" Required_argument "r"
47 "script\0" Required_argument "s"
48 "timeout\0" Required_argument "T"
Keith Younge6bb8d32011-03-07 03:18:46 +010049 "retries\0" Required_argument "t"
50 "tryagain\0" Required_argument "A"
51 "syslog\0" No_argument "S"
52 "request-option\0" Required_argument "O"
53 "no-default-options\0" No_argument "o"
54 "foreground\0" No_argument "f"
55 "background\0" No_argument "b"
56 "broadcast\0" No_argument "B"
Michel Stam9f412712014-10-30 11:59:04 +010057 IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
Keith Younge6bb8d32011-03-07 03:18:46 +010058 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
59 ;
60#endif
61/* Must match getopt32 option string order */
62enum {
63 OPT_C = 1 << 0,
64 OPT_V = 1 << 1,
65 OPT_H = 1 << 2,
66 OPT_h = 1 << 3,
67 OPT_F = 1 << 4,
68 OPT_i = 1 << 5,
69 OPT_n = 1 << 6,
70 OPT_p = 1 << 7,
71 OPT_q = 1 << 8,
72 OPT_R = 1 << 9,
73 OPT_r = 1 << 10,
74 OPT_s = 1 << 11,
75 OPT_T = 1 << 12,
76 OPT_t = 1 << 13,
77 OPT_S = 1 << 14,
78 OPT_A = 1 << 15,
79 OPT_O = 1 << 16,
80 OPT_o = 1 << 17,
81 OPT_x = 1 << 18,
82 OPT_f = 1 << 19,
83 OPT_B = 1 << 20,
84/* The rest has variable bit positions, need to be clever */
85 OPTBIT_B = 20,
86 USE_FOR_MMU( OPTBIT_b,)
87 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
88 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
89 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
90 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
91 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
92};
93
94
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +010095/*** Script execution code ***/
96
97/* get a rough idea of how long an option will be (rounding up...) */
98static const uint8_t len_of_option_as_string[] = {
Denys Vlasenko243ddcb2010-04-03 17:34:52 +020099 [OPTION_IP ] = sizeof("255.255.255.255 "),
100 [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
101 [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200102 [OPTION_6RD ] = sizeof("32 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200103 [OPTION_STRING ] = 1,
Denys Vlasenkod2266d42012-04-22 03:37:01 +0200104 [OPTION_STRING_HOST ] = 1,
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100105#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200106 [OPTION_DNS_STRING ] = 1, /* unused */
107 /* Hmmm, this severely overestimates size if SIP_SERVERS option
108 * is in domain name form: N-byte option in binary form
109 * mallocs ~16*N bytes. But it is freed almost at once.
110 */
111 [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100112#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200113// [OPTION_BOOLEAN ] = sizeof("yes "),
114 [OPTION_U8 ] = sizeof("255 "),
115 [OPTION_U16 ] = sizeof("65535 "),
116// [OPTION_S16 ] = sizeof("-32768 "),
117 [OPTION_U32 ] = sizeof("4294967295 "),
118 [OPTION_S32 ] = sizeof("-2147483684 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100119};
120
121/* note: ip is a pointer to an IP in network order, possibly misaliged */
122static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
123{
124 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
125}
126
127/* really simple implementation, just count the bits */
128static int mton(uint32_t mask)
129{
130 int i = 0;
131 mask = ntohl(mask); /* 111110000-like bit pattern */
132 while (mask) {
133 i++;
134 mask <<= 1;
135 }
136 return i;
137}
138
Denys Vlasenko85090c12014-06-16 00:17:00 +0200139#if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
Denys Vlasenko7280d202011-12-08 16:41:05 +0100140/* Check if a given label represents a valid DNS label
141 * Return pointer to the first character after the label upon success,
142 * NULL otherwise.
143 * See RFC1035, 2.3.1
144 */
145/* We don't need to be particularly anal. For example, allowing _, hyphen
146 * at the end, or leading and trailing dots would be ok, since it
147 * can't be used for attacks. (Leading hyphen can be, if someone uses
148 * cmd "$hostname"
149 * in the script: then hostname may be treated as an option)
150 */
151static const char *valid_domain_label(const char *label)
152{
153 unsigned char ch;
154 unsigned pos = 0;
155
156 for (;;) {
157 ch = *label;
158 if ((ch|0x20) < 'a' || (ch|0x20) > 'z') {
159 if (pos == 0) {
160 /* label must begin with letter */
161 return NULL;
162 }
163 if (ch < '0' || ch > '9') {
164 if (ch == '\0' || ch == '.')
165 return label;
166 /* DNS allows only '-', but we are more permissive */
167 if (ch != '-' && ch != '_')
168 return NULL;
169 }
170 }
171 label++;
172 pos++;
173 //Do we want this?
174 //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
175 // return NULL;
176 }
177}
178
179/* Check if a given name represents a valid DNS name */
180/* See RFC1035, 2.3.1 */
181static int good_hostname(const char *name)
182{
183 //const char *start = name;
184
185 for (;;) {
186 name = valid_domain_label(name);
187 if (!name)
188 return 0;
189 if (!name[0])
190 return 1;
191 //Do we want this?
192 //return ((name - start) < 1025); /* NS_MAXDNAME */
193 name++;
194 }
195}
Denys Vlasenko85090c12014-06-16 00:17:00 +0200196#else
197# define good_hostname(name) 1
198#endif
Denys Vlasenko7280d202011-12-08 16:41:05 +0100199
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100200/* Create "opt_name=opt_value" string */
Denys Vlasenkoc03602b2010-04-04 15:28:49 +0200201static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100202{
203 unsigned upper_length;
204 int len, type, optlen;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100205 char *dest, *ret;
206
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200207 /* option points to OPT_DATA, need to go back to get OPT_LEN */
208 len = option[-OPT_DATA + OPT_LEN];
Vladislav Grishenkoad8def22010-10-17 12:27:50 +0200209
Denys Vlasenkoc03602b2010-04-04 15:28:49 +0200210 type = optflag->flags & OPTION_TYPE_MASK;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100211 optlen = dhcp_option_lengths[type];
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200212 upper_length = len_of_option_as_string[type]
213 * ((unsigned)(len + optlen - 1) / (unsigned)optlen);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100214
215 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
216 dest += sprintf(ret, "%s=", opt_name);
217
218 while (len >= optlen) {
219 switch (type) {
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200220 case OPTION_IP:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100221 case OPTION_IP_PAIR:
222 dest += sprint_nip(dest, "", option);
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200223 if (type == OPTION_IP)
224 break;
225 dest += sprint_nip(dest, "/", option + 4);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100226 break;
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100227// case OPTION_BOOLEAN:
228// dest += sprintf(dest, *option ? "yes" : "no");
229// break;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100230 case OPTION_U8:
231 dest += sprintf(dest, "%u", *option);
232 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200233// case OPTION_S16:
234 case OPTION_U16: {
235 uint16_t val_u16;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100236 move_from_unaligned16(val_u16, option);
237 dest += sprintf(dest, "%u", ntohs(val_u16));
238 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200239 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100240 case OPTION_S32:
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200241 case OPTION_U32: {
242 uint32_t val_u32;
243 move_from_unaligned32(val_u32, option);
244 dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100245 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200246 }
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200247 /* Note: options which use 'return' instead of 'break'
248 * (for example, OPTION_STRING) skip the code which handles
249 * the case of list of options.
250 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100251 case OPTION_STRING:
Denys Vlasenko7280d202011-12-08 16:41:05 +0100252 case OPTION_STRING_HOST:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100253 memcpy(dest, option, len);
254 dest[len] = '\0';
Denys Vlasenko7280d202011-12-08 16:41:05 +0100255 if (type == OPTION_STRING_HOST && !good_hostname(dest))
256 safe_strncpy(dest, "bad", len);
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200257 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100258 case OPTION_STATIC_ROUTES: {
259 /* Option binary format:
260 * mask [one byte, 0..32]
261 * ip [big endian, 0..4 bytes depending on mask]
262 * router [big endian, 4 bytes]
263 * may be repeated
264 *
265 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
266 */
267 const char *pfx = "";
268
269 while (len >= 1 + 4) { /* mask + 0-byte ip + router */
270 uint32_t nip;
271 uint8_t *p;
272 unsigned mask;
273 int bytes;
274
275 mask = *option++;
276 if (mask > 32)
277 break;
278 len--;
279
280 nip = 0;
281 p = (void*) &nip;
282 bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
283 while (--bytes >= 0) {
284 *p++ = *option++;
285 len--;
286 }
287 if (len < 4)
288 break;
289
290 /* print ip/mask */
291 dest += sprint_nip(dest, pfx, (void*) &nip);
292 pfx = " ";
293 dest += sprintf(dest, "/%u ", mask);
294 /* print router */
295 dest += sprint_nip(dest, "", option);
296 option += 4;
297 len -= 4;
298 }
299
300 return ret;
301 }
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200302 case OPTION_6RD:
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200303 /* Option binary format (see RFC 5969):
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200304 * 0 1 2 3
305 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200306 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
307 * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
308 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200309 * | 6rdPrefix |
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200310 * ... (16 octets) ...
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200311 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200312 * ... 6rdBRIPv4Address(es) ...
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200313 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200314 * We convert it to a string
315 * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200316 *
317 * Sanity check: ensure that our length is at least 22 bytes, that
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200318 * IPv4MaskLen <= 32,
319 * 6rdPrefixLen <= 128,
320 * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
321 * (2nd condition need no check - it follows from 1st and 3rd).
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200322 * Else, return envvar with empty value ("optname=")
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200323 */
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200324 if (len >= (1 + 1 + 16 + 4)
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200325 && option[0] <= 32
326 && (option[1] + 32 - option[0]) <= 128
327 ) {
328 /* IPv4MaskLen */
329 dest += sprintf(dest, "%u ", *option++);
330 /* 6rdPrefixLen */
331 dest += sprintf(dest, "%u ", *option++);
332 /* 6rdPrefix */
Denys Vlasenko42816c22011-10-20 10:52:07 +0200333 dest += sprint_nip6(dest, /* "", */ option);
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200334 option += 16;
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200335 len -= 1 + 1 + 16 + 4;
336 /* "+ 4" above corresponds to the length of IPv4 addr
337 * we consume in the loop below */
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200338 while (1) {
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200339 /* 6rdBRIPv4Address(es) */
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200340 dest += sprint_nip(dest, " ", option);
341 option += 4;
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200342 len -= 4; /* do we have yet another 4+ bytes? */
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200343 if (len < 0)
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200344 break; /* no */
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200345 }
346 }
347
348 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100349#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200350 case OPTION_DNS_STRING:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100351 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
352 dest = dname_dec(option, len, ret);
353 if (dest) {
354 free(ret);
355 return dest;
356 }
357 /* error. return "optname=" string */
358 return ret;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200359 case OPTION_SIP_SERVERS:
360 /* Option binary format:
361 * type: byte
362 * type=0: domain names, dns-compressed
363 * type=1: IP addrs
364 */
365 option++;
366 len--;
367 if (option[-1] == 0) {
368 dest = dname_dec(option, len, ret);
369 if (dest) {
370 free(ret);
371 return dest;
372 }
373 } else
374 if (option[-1] == 1) {
375 const char *pfx = "";
376 while (1) {
377 len -= 4;
378 if (len < 0)
379 break;
380 dest += sprint_nip(dest, pfx, option);
381 pfx = " ";
382 option += 4;
383 }
384 }
385 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100386#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200387 } /* switch */
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200388
389 /* If we are here, try to format any remaining data
390 * in the option as another, similarly-formatted option
391 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100392 option += optlen;
393 len -= optlen;
Vladislav Grishenkoad8def22010-10-17 12:27:50 +0200394// TODO: it can be a list only if (optflag->flags & OPTION_LIST).
395// Should we bail out/warn if we see multi-ip option which is
396// not allowed to be such (for example, DHCP_BROADCAST)? -
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200397 if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100398 break;
399 *dest++ = ' ';
400 *dest = '\0';
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200401 } /* while */
402
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100403 return ret;
404}
405
406/* put all the parameters into the environment */
407static char **fill_envp(struct dhcp_packet *packet)
408{
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200409 int envc;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100410 int i;
411 char **envp, **curr;
412 const char *opt_name;
413 uint8_t *temp;
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200414 uint8_t overload = 0;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100415
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200416#define BITMAP unsigned
417#define BBITS (sizeof(BITMAP) * 8)
418#define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
419#define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
420 BITMAP found_opts[256 / BBITS];
421
422 memset(found_opts, 0, sizeof(found_opts));
423
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200424 /* We need 6 elements for:
425 * "interface=IFACE"
426 * "ip=N.N.N.N" from packet->yiaddr
427 * "siaddr=IP" from packet->siaddr_nip (unless 0)
428 * "boot_file=FILE" from packet->file (unless overloaded)
429 * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
430 * terminating NULL
431 */
432 envc = 6;
433 /* +1 element for each option, +2 for subnet option: */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100434 if (packet) {
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200435 /* note: do not search for "pad" (0) and "end" (255) options */
Denys Vlasenko7280d202011-12-08 16:41:05 +0100436//TODO: change logic to scan packet _once_
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200437 for (i = 1; i < 255; i++) {
438 temp = udhcp_get_option(packet, i);
439 if (temp) {
440 if (i == DHCP_OPTION_OVERLOAD)
441 overload = *temp;
442 else if (i == DHCP_SUBNET)
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200443 envc++; /* for $mask */
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200444 envc++;
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200445 /*if (i != DHCP_MESSAGE_TYPE)*/
446 FOUND_OPTS(i) |= BMASK(i);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100447 }
448 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100449 }
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200450 curr = envp = xzalloc(sizeof(envp[0]) * envc);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100451
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100452 *curr = xasprintf("interface=%s", client_config.interface);
453 putenv(*curr++);
454
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200455 if (!packet)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100456 return envp;
457
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200458 /* Export BOOTP fields. Fields we don't (yet?) export:
459 * uint8_t op; // always BOOTREPLY
460 * uint8_t htype; // hardware address type. 1 = 10mb ethernet
461 * uint8_t hlen; // hardware address length
462 * uint8_t hops; // used by relay agents only
463 * uint32_t xid;
464 * uint16_t secs; // elapsed since client began acquisition/renewal
465 * uint16_t flags; // only one flag so far: bcast. Never set by server
466 * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
467 * // if during renew server wants to give us differn IP?)
468 * uint32_t gateway_nip; // relay agent IP address
469 * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
470 * TODO: export gateway_nip as $giaddr?
471 */
472 /* Most important one: yiaddr as $ip */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100473 *curr = xmalloc(sizeof("ip=255.255.255.255"));
474 sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
475 putenv(*curr++);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200476 if (packet->siaddr_nip) {
477 /* IP address of next server to use in bootstrap */
478 *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
479 sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
480 putenv(*curr++);
481 }
482 if (!(overload & FILE_FIELD) && packet->file[0]) {
483 /* watch out for invalid packets */
484 *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
485 putenv(*curr++);
486 }
487 if (!(overload & SNAME_FIELD) && packet->sname[0]) {
488 /* watch out for invalid packets */
489 *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
490 putenv(*curr++);
491 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100492
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200493 /* Export known DHCP options */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100494 opt_name = dhcp_option_strings;
495 i = 0;
496 while (*opt_name) {
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200497 uint8_t code = dhcp_optflags[i].code;
498 BITMAP *found_ptr = &FOUND_OPTS(code);
499 BITMAP found_mask = BMASK(code);
500 if (!(*found_ptr & found_mask))
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100501 goto next;
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200502 *found_ptr &= ~found_mask; /* leave only unknown options */
503 temp = udhcp_get_option(packet, code);
Denys Vlasenkoc03602b2010-04-04 15:28:49 +0200504 *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100505 putenv(*curr++);
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200506 if (code == DHCP_SUBNET) {
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200507 /* Subnet option: make things like "$ip/$mask" possible */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100508 uint32_t subnet;
509 move_from_unaligned32(subnet, temp);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200510 *curr = xasprintf("mask=%u", mton(subnet));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100511 putenv(*curr++);
512 }
513 next:
514 opt_name += strlen(opt_name) + 1;
515 i++;
516 }
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200517 /* Export unknown options */
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200518 for (i = 0; i < 256;) {
519 BITMAP bitmap = FOUND_OPTS(i);
520 if (!bitmap) {
521 i += BBITS;
522 continue;
523 }
524 if (bitmap & BMASK(i)) {
525 unsigned len, ofs;
526
527 temp = udhcp_get_option(packet, i);
528 /* udhcp_get_option returns ptr to data portion,
529 * need to go back to get len
530 */
531 len = temp[-OPT_DATA + OPT_LEN];
532 *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
533 ofs = sprintf(*curr, "opt%u=", i);
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200534 *bin2hex(*curr + ofs, (void*) temp, len) = '\0';
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200535 putenv(*curr++);
536 }
537 i++;
538 }
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200539
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100540 return envp;
541}
542
543/* Call a script with a par file and env vars */
544static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
545{
546 char **envp, **curr;
547 char *argv[3];
548
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100549 envp = fill_envp(packet);
550
551 /* call script */
552 log1("Executing %s %s", client_config.script, name);
553 argv[0] = (char*) client_config.script;
554 argv[1] = (char*) name;
555 argv[2] = NULL;
556 spawn_and_wait(argv);
557
558 for (curr = envp; *curr; curr++) {
559 log2(" %s", *curr);
Denys Vlasenkodd8adde2010-06-24 05:00:50 +0200560 bb_unsetenv_and_free(*curr);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100561 }
562 free(envp);
563}
564
565
566/*** Sending/receiving packets ***/
567
Denys Vlasenko8d114452010-03-22 13:44:09 +0100568static ALWAYS_INLINE uint32_t random_xid(void)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100569{
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100570 return rand();
571}
572
573/* Initialize the packet with the proper defaults */
574static void init_packet(struct dhcp_packet *packet, char type)
575{
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100576 uint16_t secs;
577
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200578 /* Fill in: op, htype, hlen, cookie fields; message type option: */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100579 udhcp_init_header(packet, type);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200580
581 packet->xid = random_xid();
582
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100583 client_config.last_secs = monotonic_sec();
584 if (client_config.first_secs == 0)
585 client_config.first_secs = client_config.last_secs;
586 secs = client_config.last_secs - client_config.first_secs;
587 packet->secs = htons(secs);
588
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100589 memcpy(packet->chaddr, client_config.client_mac, 6);
590 if (client_config.clientid)
Denys Vlasenko7724c762010-03-26 09:32:09 +0100591 udhcp_add_binary_option(packet, client_config.clientid);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100592}
593
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100594static void add_client_options(struct dhcp_packet *packet)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100595{
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200596 int i, end, len;
597
598 udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200599
Denys Vlasenko7724c762010-03-26 09:32:09 +0100600 /* Add a "param req" option with the list of options we'd like to have
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100601 * from stubborn DHCP servers. Pull the data from the struct in common.c.
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100602 * No bounds checking because it goes towards the head of the packet. */
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200603 end = udhcp_end_option(packet->options);
604 len = 0;
Denys Vlasenko293c9452012-07-27 13:25:07 +0200605 for (i = 1; i < DHCP_END; i++) {
606 if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) {
607 packet->options[end + OPT_DATA + len] = i;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100608 len++;
609 }
610 }
611 if (len) {
612 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
613 packet->options[end + OPT_LEN] = len;
614 packet->options[end + OPT_DATA + len] = DHCP_END;
615 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100616
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200617 if (client_config.vendorclass)
618 udhcp_add_binary_option(packet, client_config.vendorclass);
619 if (client_config.hostname)
620 udhcp_add_binary_option(packet, client_config.hostname);
621 if (client_config.fqdn)
622 udhcp_add_binary_option(packet, client_config.fqdn);
623
Keith Younge6bb8d32011-03-07 03:18:46 +0100624 /* Request broadcast replies if we have no IP addr */
625 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
626 packet->flags |= htons(BROADCAST_FLAG);
627
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100628 /* Add -x options if any */
629 {
630 struct option_set *curr = client_config.options;
631 while (curr) {
Denys Vlasenko7724c762010-03-26 09:32:09 +0100632 udhcp_add_binary_option(packet, curr->data);
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100633 curr = curr->next;
634 }
635// if (client_config.sname)
636// strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
637// if (client_config.boot_file)
638// strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
639 }
Denys Vlasenko2017d482011-11-05 01:24:14 +0100640
641 // This will be needed if we remove -V VENDOR_STR in favor of
642 // -x vendor:VENDOR_STR
643 //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
644 // /* not set, set the default vendor ID */
645 // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100646}
647
648/* RFC 2131
649 * 4.4.4 Use of broadcast and unicast
650 *
651 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
652 * messages, unless the client knows the address of a DHCP server.
653 * The client unicasts DHCPRELEASE messages to the server. Because
654 * the client is declining the use of the IP address supplied by the server,
655 * the client broadcasts DHCPDECLINE messages.
656 *
657 * When the DHCP client knows the address of a DHCP server, in either
658 * INIT or REBOOTING state, the client may use that address
659 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
660 * The client may also use unicast to send DHCPINFORM messages
661 * to a known DHCP server. If the client receives no response to DHCP
662 * messages sent to the IP address of a known DHCP server, the DHCP
663 * client reverts to using the IP broadcast address.
664 */
665
666static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
667{
668 return udhcp_send_raw_packet(packet,
669 /*src*/ INADDR_ANY, CLIENT_PORT,
670 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
671 client_config.ifindex);
672}
673
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100674static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
675{
676 if (server)
677 return udhcp_send_kernel_packet(packet,
678 ciaddr, CLIENT_PORT,
679 server, SERVER_PORT);
680 return raw_bcast_from_client_config_ifindex(packet);
681}
682
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100683/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200684/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200685static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100686{
687 struct dhcp_packet packet;
688
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200689 /* Fill in: op, htype, hlen, cookie, chaddr fields,
690 * random xid field (we override it below),
691 * client-id option (unless -C), message type option:
692 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100693 init_packet(&packet, DHCPDISCOVER);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200694
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100695 packet.xid = xid;
696 if (requested)
Denys Vlasenko7724c762010-03-26 09:32:09 +0100697 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200698
699 /* Add options: maxsize,
700 * optionally: hostname, fqdn, vendorclass,
701 * "param req" option according to -O, options specified with -x
702 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100703 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100704
705 bb_info_msg("Sending discover...");
706 return raw_bcast_from_client_config_ifindex(&packet);
707}
708
709/* Broadcast a DHCP request message */
710/* RFC 2131 3.1 paragraph 3:
711 * "The client _broadcasts_ a DHCPREQUEST message..."
712 */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200713/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200714static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100715{
716 struct dhcp_packet packet;
717 struct in_addr addr;
718
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200719/*
720 * RFC 2131 4.3.2 DHCPREQUEST message
721 * ...
722 * If the DHCPREQUEST message contains a 'server identifier'
723 * option, the message is in response to a DHCPOFFER message.
724 * Otherwise, the message is a request to verify or extend an
725 * existing lease. If the client uses a 'client identifier'
726 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
727 * in all subsequent messages. If the client included a list
728 * of requested parameters in a DHCPDISCOVER message, it MUST
729 * include that list in all subsequent messages.
730 */
731 /* Fill in: op, htype, hlen, cookie, chaddr fields,
732 * random xid field (we override it below),
733 * client-id option (unless -C), message type option:
734 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100735 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200736
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100737 packet.xid = xid;
Denys Vlasenko7724c762010-03-26 09:32:09 +0100738 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200739
Denys Vlasenko7724c762010-03-26 09:32:09 +0100740 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200741
742 /* Add options: maxsize,
743 * optionally: hostname, fqdn, vendorclass,
744 * "param req" option according to -O, and options specified with -x
745 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100746 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100747
748 addr.s_addr = requested;
749 bb_info_msg("Sending select for %s...", inet_ntoa(addr));
750 return raw_bcast_from_client_config_ifindex(&packet);
751}
752
753/* Unicast or broadcast a DHCP renew message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200754/* NOINLINE: limit stack usage in caller */
755static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100756{
757 struct dhcp_packet packet;
758
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200759/*
760 * RFC 2131 4.3.2 DHCPREQUEST message
761 * ...
762 * DHCPREQUEST generated during RENEWING state:
763 *
764 * 'server identifier' MUST NOT be filled in, 'requested IP address'
765 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
766 * client's IP address. In this situation, the client is completely
767 * configured, and is trying to extend its lease. This message will
768 * be unicast, so no relay agents will be involved in its
769 * transmission. Because 'giaddr' is therefore not filled in, the
770 * DHCP server will trust the value in 'ciaddr', and use it when
771 * replying to the client.
772 */
773 /* Fill in: op, htype, hlen, cookie, chaddr fields,
774 * random xid field (we override it below),
775 * client-id option (unless -C), message type option:
776 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100777 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200778
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100779 packet.xid = xid;
780 packet.ciaddr = ciaddr;
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200781
782 /* Add options: maxsize,
783 * optionally: hostname, fqdn, vendorclass,
784 * "param req" option according to -O, and options specified with -x
785 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100786 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100787
788 bb_info_msg("Sending renew...");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100789 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100790}
791
792#if ENABLE_FEATURE_UDHCPC_ARPING
793/* Broadcast a DHCP decline message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200794/* NOINLINE: limit stack usage in caller */
Denys Vlasenko860491c2011-11-18 02:09:13 +0100795static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100796{
797 struct dhcp_packet packet;
798
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200799 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
800 * client-id option (unless -C), message type option:
801 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100802 init_packet(&packet, DHCPDECLINE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200803
Denys Vlasenko860491c2011-11-18 02:09:13 +0100804#if 0
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200805 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
806 * but in case the server is buggy and wants DHCPDECLINE's xid
807 * to match the xid which started entire handshake,
808 * we use the same xid we used in initial DHCPDISCOVER:
809 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100810 packet.xid = xid;
Denys Vlasenko860491c2011-11-18 02:09:13 +0100811#endif
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200812 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
Denys Vlasenko7724c762010-03-26 09:32:09 +0100813 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200814
Denys Vlasenko7724c762010-03-26 09:32:09 +0100815 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100816
817 bb_info_msg("Sending decline...");
818 return raw_bcast_from_client_config_ifindex(&packet);
819}
820#endif
821
822/* Unicast a DHCP release message */
823static int send_release(uint32_t server, uint32_t ciaddr)
824{
825 struct dhcp_packet packet;
826
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200827 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
828 * client-id option (unless -C), message type option:
829 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100830 init_packet(&packet, DHCPRELEASE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200831
832 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100833 packet.ciaddr = ciaddr;
834
Denys Vlasenko7724c762010-03-26 09:32:09 +0100835 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100836
837 bb_info_msg("Sending release...");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100838 /* Note: normally we unicast here since "server" is not zero.
839 * However, there _are_ people who run "address-less" DHCP servers,
840 * and reportedly ISC dhcp client and Windows allow that.
841 */
842 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100843}
844
845/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200846/* NOINLINE: limit stack usage in caller */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100847static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
848{
849 int bytes;
850 struct ip_udp_dhcp_packet packet;
851 uint16_t check;
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200852 unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
853 struct iovec iov;
854 struct msghdr msg;
855 struct cmsghdr *cmsg;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100856
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200857 /* used to use just safe_read(fd, &packet, sizeof(packet))
858 * but we need to check for TP_STATUS_CSUMNOTREADY :(
859 */
860 iov.iov_base = &packet;
861 iov.iov_len = sizeof(packet);
862 memset(&msg, 0, sizeof(msg));
863 msg.msg_iov = &iov;
864 msg.msg_iovlen = 1;
865 msg.msg_control = cmsgbuf;
866 msg.msg_controllen = sizeof(cmsgbuf);
867 for (;;) {
868 bytes = recvmsg(fd, &msg, 0);
869 if (bytes < 0) {
870 if (errno == EINTR)
871 continue;
872 log1("Packet read error, ignoring");
873 /* NB: possible down interface, etc. Caller should pause. */
874 return bytes; /* returns -1 */
875 }
876 break;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100877 }
878
879 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
880 log1("Packet is too short, ignoring");
881 return -2;
882 }
883
884 if (bytes < ntohs(packet.ip.tot_len)) {
885 /* packet is bigger than sizeof(packet), we did partial read */
886 log1("Oversized packet, ignoring");
887 return -2;
888 }
889
890 /* ignore any extra garbage bytes */
891 bytes = ntohs(packet.ip.tot_len);
892
893 /* make sure its the right packet for us, and that it passes sanity checks */
Denys Vlasenko7981d792011-10-20 10:34:05 +0200894 if (packet.ip.protocol != IPPROTO_UDP
895 || packet.ip.version != IPVERSION
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100896 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
897 || packet.udp.dest != htons(CLIENT_PORT)
898 /* || bytes > (int) sizeof(packet) - can't happen */
899 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
900 ) {
901 log1("Unrelated/bogus packet, ignoring");
902 return -2;
903 }
904
905 /* verify IP checksum */
906 check = packet.ip.check;
907 packet.ip.check = 0;
Baruch Siache8f36332011-09-07 17:52:37 +0200908 if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100909 log1("Bad IP header checksum, ignoring");
910 return -2;
911 }
912
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200913 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
914 if (cmsg->cmsg_level == SOL_PACKET
915 && cmsg->cmsg_type == PACKET_AUXDATA
916 ) {
917 /* some VMs don't checksum UDP and TCP data
918 * they send to the same physical machine,
919 * here we detect this case:
920 */
921 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
922 if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
923 goto skip_udp_sum_check;
924 }
925 }
926
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100927 /* verify UDP checksum. IP header has to be modified for this */
928 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
929 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
930 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
931 check = packet.udp.check;
932 packet.udp.check = 0;
Baruch Siache8f36332011-09-07 17:52:37 +0200933 if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100934 log1("Packet with bad UDP checksum received, ignoring");
935 return -2;
936 }
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200937 skip_udp_sum_check:
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100938
Denys Vlasenko7981d792011-10-20 10:34:05 +0200939 if (packet.data.cookie != htonl(DHCP_MAGIC)) {
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100940 bb_info_msg("Packet with bad magic, ignoring");
941 return -2;
942 }
Denys Vlasenko7981d792011-10-20 10:34:05 +0200943
Denys Vlasenkod38ca032011-11-05 01:25:03 +0100944 log1("Received a packet");
Denys Vlasenko7981d792011-10-20 10:34:05 +0200945 udhcp_dump_packet(&packet.data);
946
947 bytes -= sizeof(packet.ip) + sizeof(packet.udp);
948 memcpy(dhcp_pkt, &packet.data, bytes);
949 return bytes;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100950}
Denys Vlasenko6b24d532010-03-22 13:42:13 +0100951
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100952
953/*** Main ***/
954
955static int sockfd = -1;
956
957#define LISTEN_NONE 0
958#define LISTEN_KERNEL 1
959#define LISTEN_RAW 2
960static smallint listen_mode;
961
962/* initial state: (re)start DHCP negotiation */
963#define INIT_SELECTING 0
964/* discover was sent, DHCPOFFER reply received */
965#define REQUESTING 1
966/* select/renew was sent, DHCPACK reply received */
967#define BOUND 2
968/* half of lease passed, want to renew it by sending unicast renew requests */
969#define RENEWING 3
970/* renew requests were not answered, lease is almost over, send broadcast renew */
971#define REBINDING 4
972/* manually requested renew (SIGUSR1) */
973#define RENEW_REQUESTED 5
974/* release, possibly manually requested (SIGUSR2) */
975#define RELEASED 6
976static smallint state;
977
Denys Vlasenko6b24d532010-03-22 13:42:13 +0100978static int udhcp_raw_socket(int ifindex)
979{
980 int fd;
981 struct sockaddr_ll sock;
982
Denys Vlasenko6b24d532010-03-22 13:42:13 +0100983 log1("Opening raw socket on ifindex %d", ifindex); //log2?
984
985 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
Denys Vlasenko744ee5d2014-02-07 17:38:52 +0100986 /* ^^^^^
987 * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
988 * ETH_P_IP: want to receive only packets with IPv4 eth type
989 */
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200990 log1("Got raw socket fd"); //log2?
Denys Vlasenko6b24d532010-03-22 13:42:13 +0100991
Vladislav Grishenko713e6d72011-02-14 04:50:30 +0100992 sock.sll_family = AF_PACKET;
993 sock.sll_protocol = htons(ETH_P_IP);
994 sock.sll_ifindex = ifindex;
995 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
996
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +0100997#if 0 /* Several users reported breakage when BPF filter is used */
Vladislav Grishenko713e6d72011-02-14 04:50:30 +0100998 if (CLIENT_PORT == 68) {
999 /* Use only if standard port is in use */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001000 /*
1001 * I've selected not to see LL header, so BPF doesn't see it, too.
1002 * The filter may also pass non-IP and non-ARP packets, but we do
1003 * a more complete check when receiving the message in userspace.
1004 *
1005 * and filter shamelessly stolen from:
1006 *
1007 * http://www.flamewarmaster.de/software/dhcpclient/
1008 *
1009 * There are a few other interesting ideas on that page (look under
1010 * "Motivation"). Use of netlink events is most interesting. Think
1011 * of various network servers listening for events and reconfiguring.
1012 * That would obsolete sending HUP signals and/or make use of restarts.
1013 *
1014 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
1015 * License: GPL v2.
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001016 */
1017 static const struct sock_filter filter_instr[] = {
1018 /* load 9th byte (protocol) */
1019 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
1020 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
1021 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
1022 /* L1: load halfword from offset 6 (flags and frag offset) */
1023 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
1024 /* jump to L4 if any bits in frag offset field are set, else to L2 */
1025 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
1026 /* L2: skip IP header (load index reg with header len) */
1027 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
1028 /* load udp destination port from halfword[header_len + 2] */
1029 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
1030 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
1031 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
Denys Vlasenkoffc3a932014-02-19 14:17:11 +01001032 /* L3: accept packet ("accept 0x7fffffff bytes") */
1033 /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
1034 BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
1035 /* L4: discard packet ("accept zero bytes") */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001036 BPF_STMT(BPF_RET|BPF_K, 0),
1037 };
1038 static const struct sock_fprog filter_prog = {
1039 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
1040 /* casting const away: */
1041 .filter = (struct sock_filter *) filter_instr,
1042 };
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001043 /* Ignoring error (kernel may lack support for this) */
1044 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
1045 sizeof(filter_prog)) >= 0)
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001046 log1("Attached filter to raw socket fd"); // log?
1047 }
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001048#endif
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001049
1050 if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA,
1051 &const_int_1, sizeof(int)) < 0
1052 ) {
1053 if (errno != ENOPROTOOPT)
1054 log1("Can't set PACKET_AUXDATA on raw socket");
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001055 }
1056
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001057 log1("Created raw socket");
1058
1059 return fd;
1060}
1061
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001062static void change_listen_mode(int new_mode)
Mike Frysinger7031f622006-05-08 03:20:50 +00001063{
Denys Vlasenko4945ed32009-06-17 11:58:11 +02001064 log1("Entering listen mode: %s",
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001065 new_mode != LISTEN_NONE
1066 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
1067 : "none"
1068 );
Denis Vlasenko517413f2008-12-10 11:16:47 +00001069
1070 listen_mode = new_mode;
Denis Vlasenkofbd29182007-04-07 01:05:47 +00001071 if (sockfd >= 0) {
1072 close(sockfd);
1073 sockfd = -1;
1074 }
Denis Vlasenko517413f2008-12-10 11:16:47 +00001075 if (new_mode == LISTEN_KERNEL)
1076 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
1077 else if (new_mode != LISTEN_NONE)
1078 sockfd = udhcp_raw_socket(client_config.ifindex);
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001079 /* else LISTEN_NONE: sockfd stays closed */
Mike Frysinger7031f622006-05-08 03:20:50 +00001080}
1081
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001082/* Called only on SIGUSR1 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001083static void perform_renew(void)
1084{
Denis Vlasenko3538b9a2006-09-06 18:36:50 +00001085 bb_info_msg("Performing a DHCP renew");
Mike Frysinger7031f622006-05-08 03:20:50 +00001086 switch (state) {
1087 case BOUND:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001088 change_listen_mode(LISTEN_KERNEL);
Mike Frysinger7031f622006-05-08 03:20:50 +00001089 case RENEWING:
1090 case REBINDING:
1091 state = RENEW_REQUESTED;
1092 break;
1093 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
Rob Landley3f785612006-05-28 01:06:36 +00001094 udhcp_run_script(NULL, "deconfig");
Mike Frysinger7031f622006-05-08 03:20:50 +00001095 case REQUESTING:
1096 case RELEASED:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001097 change_listen_mode(LISTEN_RAW);
Mike Frysinger7031f622006-05-08 03:20:50 +00001098 state = INIT_SELECTING;
1099 break;
1100 case INIT_SELECTING:
1101 break;
1102 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001103}
1104
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001105static void perform_release(uint32_t server_addr, uint32_t requested_ip)
Mike Frysinger7031f622006-05-08 03:20:50 +00001106{
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001107 char buffer[sizeof("255.255.255.255")];
Mike Frysinger7031f622006-05-08 03:20:50 +00001108 struct in_addr temp_addr;
1109
1110 /* send release packet */
1111 if (state == BOUND || state == RENEWING || state == REBINDING) {
1112 temp_addr.s_addr = server_addr;
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001113 strcpy(buffer, inet_ntoa(temp_addr));
Mike Frysinger7031f622006-05-08 03:20:50 +00001114 temp_addr.s_addr = requested_ip;
Denis Vlasenko3538b9a2006-09-06 18:36:50 +00001115 bb_info_msg("Unicasting a release of %s to %s",
Mike Frysinger7031f622006-05-08 03:20:50 +00001116 inet_ntoa(temp_addr), buffer);
1117 send_release(server_addr, requested_ip); /* unicast */
Rob Landley3f785612006-05-28 01:06:36 +00001118 udhcp_run_script(NULL, "deconfig");
Mike Frysinger7031f622006-05-08 03:20:50 +00001119 }
Denis Vlasenko3538b9a2006-09-06 18:36:50 +00001120 bb_info_msg("Entering released state");
Mike Frysinger7031f622006-05-08 03:20:50 +00001121
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001122 change_listen_mode(LISTEN_NONE);
Mike Frysinger7031f622006-05-08 03:20:50 +00001123 state = RELEASED;
Mike Frysinger7031f622006-05-08 03:20:50 +00001124}
1125
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001126static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
1127{
1128 uint8_t *storage;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001129 int len = strnlen(str, 255);
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001130 storage = xzalloc(len + extra + OPT_DATA);
1131 storage[OPT_CODE] = code;
1132 storage[OPT_LEN] = len + extra;
1133 memcpy(storage + extra + OPT_DATA, str, len);
1134 return storage;
1135}
1136
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001137#if BB_MMU
1138static void client_background(void)
1139{
1140 bb_daemonize(0);
1141 logmode &= ~LOGMODE_STDIO;
1142 /* rewrite pidfile, as our pid is different now */
1143 write_pidfile(client_config.pidfile);
1144}
1145#endif
1146
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001147//usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1148//usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1149//usage:#else
1150//usage:# define IF_UDHCP_VERBOSE(...)
1151//usage:#endif
1152//usage:#define udhcpc_trivial_usage
Michel Stam9f412712014-10-30 11:59:04 +01001153//usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001154//usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
1155//usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001156//usage:#define udhcpc_full_usage "\n"
1157//usage: IF_LONG_OPTS(
1158//usage: "\n -i,--interface IFACE Interface to use (default eth0)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001159//usage: IF_FEATURE_UDHCP_PORT(
1160//usage: "\n -P,--client-port PORT Use PORT (default 68)"
1161//usage: )
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001162//usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001163//usage: "\n -p,--pidfile FILE Create pidfile"
Keith Younge6bb8d32011-03-07 03:18:46 +01001164//usage: "\n -B,--broadcast Request broadcast replies"
Denys Vlasenkoaadb4852013-08-05 02:21:36 +02001165//usage: "\n -t,--retries N Send up to N discover packets (default 3)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001166//usage: "\n -T,--timeout SEC Pause between packets (default 3)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001167//usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001168//usage: "\n -n,--now Exit if lease is not obtained"
1169//usage: "\n -q,--quit Exit after obtaining lease"
1170//usage: "\n -R,--release Release IP on exit"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001171//usage: "\n -f,--foreground Run in foreground"
1172//usage: USE_FOR_MMU(
1173//usage: "\n -b,--background Background if lease is not obtained"
1174//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001175//usage: "\n -S,--syslog Log to syslog too"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001176//usage: IF_FEATURE_UDHCPC_ARPING(
Michel Stam9f412712014-10-30 11:59:04 +01001177//usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001178//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001179//usage: "\n -r,--request IP Request this IP address"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001180//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
1181//usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001182//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001183//usage: "\n Examples of string, numeric, and hex byte opts:"
1184//usage: "\n -x hostname:bbox - option 12"
1185//usage: "\n -x lease:3600 - option 51 (lease time)"
1186//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001187//usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001188//usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001189//usage: "\n -C,--clientid-none Don't send MAC as client identifier"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001190//usage: IF_UDHCP_VERBOSE(
1191//usage: "\n -v Verbose"
1192//usage: )
1193//usage: )
1194//usage: IF_NOT_LONG_OPTS(
1195//usage: "\n -i IFACE Interface to use (default eth0)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001196//usage: IF_FEATURE_UDHCP_PORT(
1197//usage: "\n -P PORT Use PORT (default 68)"
1198//usage: )
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001199//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001200//usage: "\n -p FILE Create pidfile"
Keith Younge6bb8d32011-03-07 03:18:46 +01001201//usage: "\n -B Request broadcast replies"
Denys Vlasenkoaadb4852013-08-05 02:21:36 +02001202//usage: "\n -t N Send up to N discover packets (default 3)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001203//usage: "\n -T SEC Pause between packets (default 3)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001204//usage: "\n -A SEC Wait if lease is not obtained (default 20)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001205//usage: "\n -n Exit if lease is not obtained"
1206//usage: "\n -q Exit after obtaining lease"
1207//usage: "\n -R Release IP on exit"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001208//usage: "\n -f Run in foreground"
1209//usage: USE_FOR_MMU(
1210//usage: "\n -b Background if lease is not obtained"
1211//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001212//usage: "\n -S Log to syslog too"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001213//usage: IF_FEATURE_UDHCPC_ARPING(
Michel Stam9f412712014-10-30 11:59:04 +01001214//usage: "\n -a[MSEC] Validate offered address with ARP ping"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001215//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001216//usage: "\n -r IP Request this IP address"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001217//usage: "\n -o Don't request any options (unless -O is given)"
1218//usage: "\n -O OPT Request option OPT from server (cumulative)"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001219//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1220//usage: "\n Examples of string, numeric, and hex byte opts:"
1221//usage: "\n -x hostname:bbox - option 12"
1222//usage: "\n -x lease:3600 - option 51 (lease time)"
1223//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001224//usage: "\n -F NAME Ask server to update DNS mapping for NAME"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001225//usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001226//usage: "\n -C Don't send MAC as client identifier"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001227//usage: IF_UDHCP_VERBOSE(
1228//usage: "\n -v Verbose"
1229//usage: )
1230//usage: )
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001231//usage: "\nSignals:"
Denys Vlasenko50089fc2011-11-07 15:44:46 +01001232//usage: "\n USR1 Renew lease"
1233//usage: "\n USR2 Release lease"
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001234
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001235
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +00001236int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +00001237int udhcpc_main(int argc UNUSED_PARAM, char **argv)
Mike Frysinger7031f622006-05-08 03:20:50 +00001238{
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001239 uint8_t *message;
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001240 const char *str_V, *str_h, *str_F, *str_r;
Michel Stam9f412712014-10-30 11:59:04 +01001241 IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001242 IF_FEATURE_UDHCP_PORT(char *str_P;)
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001243 void *clientid_mac_ptr;
Denis Vlasenko19183682007-12-10 07:03:38 +00001244 llist_t *list_O = NULL;
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001245 llist_t *list_x = NULL;
Denis Vlasenko68af8e72007-11-22 21:41:14 +00001246 int tryagain_timeout = 20;
1247 int discover_timeout = 3;
1248 int discover_retries = 3;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001249 uint32_t server_addr = server_addr; /* for compiler */
1250 uint32_t requested_ip = 0;
Denys Vlasenko860491c2011-11-18 02:09:13 +01001251 uint32_t xid = xid; /* for compiler */
Denis Vlasenkob539c842007-11-29 08:17:45 +00001252 int packet_num;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001253 int timeout; /* must be signed */
Denis Vlasenko19903f02008-05-21 07:03:03 +00001254 unsigned already_waited_sec;
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001255 unsigned opt;
Michel Stam9f412712014-10-30 11:59:04 +01001256 IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
Mike Frysinger7031f622006-05-08 03:20:50 +00001257 int max_fd;
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001258 int retval;
Denis Vlasenko80edead2007-08-02 22:31:05 +00001259 fd_set rfds;
Mike Frysinger7031f622006-05-08 03:20:50 +00001260
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001261 /* Default options */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001262 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1263 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001264 client_config.interface = "eth0";
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001265 client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001266 str_V = "udhcp "BB_VER;
Mike Frysinger7031f622006-05-08 03:20:50 +00001267
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001268 /* Parse command line */
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001269 /* O,x: list; -T,-t,-A take numeric param */
Leonid Lisovskiy6c9c0a12011-10-18 00:35:47 +02001270 opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
Denys Vlasenkof3b92d32009-06-19 12:10:38 +02001271 IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
Keith Younge6bb8d32011-03-07 03:18:46 +01001272 opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001273 USE_FOR_MMU("b")
Michel Stam9f412712014-10-30 11:59:04 +01001274 IF_FEATURE_UDHCPC_ARPING("a::")
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001275 IF_FEATURE_UDHCP_PORT("P:")
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001276 "v"
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001277 , &str_V, &str_h, &str_h, &str_F
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001278 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
1279 , &client_config.script /* s */
1280 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
Denis Vlasenko19183682007-12-10 07:03:38 +00001281 , &list_O
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001282 , &list_x
Michel Stam9f412712014-10-30 11:59:04 +01001283 IF_FEATURE_UDHCPC_ARPING(, &str_a)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001284 IF_FEATURE_UDHCP_PORT(, &str_P)
Leonid Lisovskiy6c9c0a12011-10-18 00:35:47 +02001285 IF_UDHCP_VERBOSE(, &dhcp_verbose)
Denys Vlasenko7e21f042011-11-08 11:39:41 +01001286 );
Denys Vlasenko2017d482011-11-05 01:24:14 +01001287 if (opt & (OPT_h|OPT_H)) {
1288 //msg added 2011-11
1289 bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001290 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
Denys Vlasenko2017d482011-11-05 01:24:14 +01001291 }
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001292 if (opt & OPT_F) {
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001293 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001294 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001295 /* Flag bits: 0000NEOS
1296 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1297 * O: 1 = Server indicates to client that DNS has been updated regardless
1298 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1299 * not "host.domain.com". Format 0 is obsolete.
1300 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1301 * Two [0] bytes which follow are deprecated and must be 0.
1302 */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001303 client_config.fqdn[OPT_DATA + 0] = 0x1;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001304 /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1305 /*client_config.fqdn[OPT_DATA + 2] = 0; */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001306 }
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001307 if (opt & OPT_r)
1308 requested_ip = inet_addr(str_r);
Denis Vlasenkod55fe3e2008-02-04 13:12:16 +00001309#if ENABLE_FEATURE_UDHCP_PORT
1310 if (opt & OPT_P) {
1311 CLIENT_PORT = xatou16(str_P);
1312 SERVER_PORT = CLIENT_PORT - 1;
1313 }
1314#endif
Michel Stam9f412712014-10-30 11:59:04 +01001315 IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
Denis Vlasenko19183682007-12-10 07:03:38 +00001316 while (list_O) {
Denis Vlasenko18c93022008-08-27 22:29:43 +00001317 char *optstr = llist_pop(&list_O);
Denys Vlasenko5d3aace2011-06-04 05:07:16 +02001318 unsigned n = bb_strtou(optstr, NULL, 0);
1319 if (errno || n > 254) {
1320 n = udhcp_option_idx(optstr);
1321 n = dhcp_optflags[n].code;
1322 }
Denis Vlasenko19183682007-12-10 07:03:38 +00001323 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
Denis Vlasenko19183682007-12-10 07:03:38 +00001324 }
Denys Vlasenko293c9452012-07-27 13:25:07 +02001325 if (!(opt & OPT_o)) {
1326 unsigned i, n;
1327 for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
1328 if (dhcp_optflags[i].flags & OPTION_REQ) {
1329 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
1330 }
1331 }
1332 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001333 while (list_x) {
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001334 char *optstr = llist_pop(&list_x);
1335 char *colon = strchr(optstr, ':');
1336 if (colon)
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001337 *colon = ' ';
Denys Vlasenko9c0ea862010-04-04 02:12:03 +02001338 /* now it looks similar to udhcpd's config file line:
1339 * "optname optval", using the common routine: */
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001340 udhcp_str2optset(optstr, &client_config.options);
1341 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001342
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001343 if (udhcp_read_interface(client_config.interface,
1344 &client_config.ifindex,
1345 NULL,
1346 client_config.client_mac)
1347 ) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001348 return 1;
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001349 }
1350
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001351 clientid_mac_ptr = NULL;
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001352 if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
1353 /* not suppressed and not set, set the default client ID */
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001354 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
1355 client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001356 clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
1357 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001358 }
Denys Vlasenko2017d482011-11-05 01:24:14 +01001359 if (str_V[0] != '\0') {
1360 // can drop -V, str_V, client_config.vendorclass,
1361 // but need to add "vendor" to the list of recognized
1362 // string opts for this to work;
1363 // and need to tweak add_client_options() too...
1364 // ...so the question is, should we?
1365 //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001366 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
Denys Vlasenko2017d482011-11-05 01:24:14 +01001367 }
1368
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001369#if !BB_MMU
1370 /* on NOMMU reexec (i.e., background) early */
1371 if (!(opt & OPT_f)) {
1372 bb_daemonize_or_rexec(0 /* flags */, argv);
Denis Vlasenkoa19e6492009-03-11 14:40:00 +00001373 logmode = LOGMODE_NONE;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001374 }
1375#endif
1376 if (opt & OPT_S) {
Denis Vlasenko5e4fda02009-03-08 23:46:48 +00001377 openlog(applet_name, LOG_PID, LOG_DAEMON);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001378 logmode |= LOGMODE_SYSLOG;
1379 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001380
Denis Vlasenko80edead2007-08-02 22:31:05 +00001381 /* Make sure fd 0,1,2 are open */
1382 bb_sanitize_stdio();
1383 /* Equivalent of doing a fflush after every \n */
1384 setlinebuf(stdout);
Denis Vlasenko80edead2007-08-02 22:31:05 +00001385 /* Create pidfile */
1386 write_pidfile(client_config.pidfile);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001387 /* Goes to stdout (unless NOMMU) and possibly syslog */
Denis Vlasenkodef88982007-10-07 17:06:01 +00001388 bb_info_msg("%s (v"BB_VER") started", applet_name);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001389 /* Set up the signal pipe */
Mike Frysinger7031f622006-05-08 03:20:50 +00001390 udhcp_sp_setup();
Denys Vlasenko8d114452010-03-22 13:44:09 +01001391 /* We want random_xid to be random... */
1392 srand(monotonic_us());
Mike Frysinger7031f622006-05-08 03:20:50 +00001393
1394 state = INIT_SELECTING;
Rob Landley3f785612006-05-28 01:06:36 +00001395 udhcp_run_script(NULL, "deconfig");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001396 change_listen_mode(LISTEN_RAW);
Denis Vlasenkob539c842007-11-29 08:17:45 +00001397 packet_num = 0;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001398 timeout = 0;
Denis Vlasenko19903f02008-05-21 07:03:03 +00001399 already_waited_sec = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001400
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001401 /* Main event loop. select() waits on signal pipe and possibly
1402 * on sockfd.
1403 * "continue" statements in code below jump to the top of the loop.
1404 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001405 for (;;) {
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001406 struct timeval tv;
1407 struct dhcp_packet packet;
Denis Vlasenkoec64a572009-01-14 00:28:03 +00001408 /* silence "uninitialized!" warning */
1409 unsigned timestamp_before_wait = timestamp_before_wait;
Mike Frysinger7031f622006-05-08 03:20:50 +00001410
Denis Vlasenko517413f2008-12-10 11:16:47 +00001411 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
1412
1413 /* Was opening raw or udp socket here
1414 * if (listen_mode != LISTEN_NONE && sockfd < 0),
1415 * but on fast network renew responses return faster
1416 * than we open sockets. Thus this code is moved
1417 * to change_listen_mode(). Thus we open listen socket
1418 * BEFORE we send renew request (see "case BOUND:"). */
1419
Denis Vlasenkofbd29182007-04-07 01:05:47 +00001420 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
Mike Frysinger7031f622006-05-08 03:20:50 +00001421
Denis Vlasenko19903f02008-05-21 07:03:03 +00001422 tv.tv_sec = timeout - already_waited_sec;
Denis Vlasenkob2342912008-05-21 07:02:16 +00001423 tv.tv_usec = 0;
Denys Vlasenko8d114452010-03-22 13:44:09 +01001424 retval = 0;
1425 /* If we already timed out, fall through with retval = 0, else... */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001426 if ((int)tv.tv_sec > 0) {
Denys Vlasenko085b2932012-06-02 23:53:53 +02001427 log1("Waiting on select %u seconds", (int)tv.tv_sec);
Denis Vlasenkob2342912008-05-21 07:02:16 +00001428 timestamp_before_wait = (unsigned)monotonic_sec();
Mike Frysinger7031f622006-05-08 03:20:50 +00001429 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
Denis Vlasenkob2342912008-05-21 07:02:16 +00001430 if (retval < 0) {
1431 /* EINTR? A signal was caught, don't panic */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001432 if (errno == EINTR) {
1433 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
Denis Vlasenkob2342912008-05-21 07:02:16 +00001434 continue;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001435 }
Denis Vlasenko80edead2007-08-02 22:31:05 +00001436 /* Else: an error occured, panic! */
1437 bb_perror_msg_and_die("select");
1438 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001439 }
1440
1441 /* If timeout dropped to zero, time to become active:
1442 * resend discover/renew/whatever
1443 */
1444 if (retval == 0) {
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001445 /* When running on a bridge, the ifindex may have changed
1446 * (e.g. if member interfaces were added/removed
1447 * or if the status of the bridge changed).
1448 * Refresh ifindex and client_mac:
1449 */
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001450 if (udhcp_read_interface(client_config.interface,
1451 &client_config.ifindex,
1452 NULL,
1453 client_config.client_mac)
1454 ) {
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001455 goto ret0; /* iface is gone? */
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001456 }
1457 if (clientid_mac_ptr)
1458 memcpy(clientid_mac_ptr, client_config.client_mac, 6);
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001459
Denis Vlasenkof1980f62008-09-26 09:34:59 +00001460 /* We will restart the wait in any case */
Denis Vlasenko19903f02008-05-21 07:03:03 +00001461 already_waited_sec = 0;
1462
Mike Frysinger7031f622006-05-08 03:20:50 +00001463 switch (state) {
1464 case INIT_SELECTING:
Felix Fietkau1c7a58d2012-09-27 16:22:24 +02001465 if (!discover_retries || packet_num < discover_retries) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001466 if (packet_num == 0)
1467 xid = random_xid();
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001468 /* broadcast */
1469 send_discover(xid, requested_ip);
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001470 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001471 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001472 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001473 }
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001474 leasefail:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001475 udhcp_run_script(NULL, "leasefail");
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001476#if BB_MMU /* -b is not supported on NOMMU */
1477 if (opt & OPT_b) { /* background if no lease */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001478 bb_info_msg("No lease, forking to background");
1479 client_background();
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001480 /* do not background again! */
1481 opt = ((opt & ~OPT_b) | OPT_f);
1482 } else
1483#endif
1484 if (opt & OPT_n) { /* abort if no lease */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001485 bb_info_msg("No lease, failing");
1486 retval = 1;
1487 goto ret;
1488 }
Denis Vlasenko6de89942008-05-21 07:05:06 +00001489 /* wait before trying again */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001490 timeout = tryagain_timeout;
1491 packet_num = 0;
1492 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001493 case REQUESTING:
Felix Fietkau1c7a58d2012-09-27 16:22:24 +02001494 if (!discover_retries || packet_num < discover_retries) {
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001495 /* send broadcast select packet */
1496 send_select(xid, server_addr, requested_ip);
Denis Vlasenko6de89942008-05-21 07:05:06 +00001497 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001498 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001499 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001500 }
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001501 /* Timed out, go back to init state.
1502 * "discover...select...discover..." loops
Denis Vlasenko7d9399e2008-09-26 22:21:03 +00001503 * were seen in the wild. Treat them similarly
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001504 * to "no response to discover" case */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001505 change_listen_mode(LISTEN_RAW);
Denis Vlasenko7d9399e2008-09-26 22:21:03 +00001506 state = INIT_SELECTING;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001507 goto leasefail;
Mike Frysinger7031f622006-05-08 03:20:50 +00001508 case BOUND:
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001509 /* 1/2 lease passed, enter renewing state */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001510 state = RENEWING;
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001511 client_config.first_secs = 0; /* make secs field count from 0 */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001512 change_listen_mode(LISTEN_KERNEL);
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001513 log1("Entering renew state");
Mike Frysinger7031f622006-05-08 03:20:50 +00001514 /* fall right through */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001515 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1516 case_RENEW_REQUESTED:
Mike Frysinger7031f622006-05-08 03:20:50 +00001517 case RENEWING:
Denis Vlasenko19903f02008-05-21 07:03:03 +00001518 if (timeout > 60) {
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001519 /* send an unicast renew request */
1520 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1521 * a new UDP socket for sending inside send_renew.
1522 * I hazard to guess existing listening socket
1523 * is somehow conflicting with it, but why is it
1524 * not deterministic then?! Strange.
Denys Vlasenko753a3ce2009-07-19 04:27:10 +02001525 * Anyway, it does recover by eventually failing through
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001526 * into INIT_SELECTING state.
1527 */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001528 send_renew(xid, server_addr, requested_ip);
Denis Vlasenko19903f02008-05-21 07:03:03 +00001529 timeout >>= 1;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001530 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001531 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001532 /* Timed out, enter rebinding state */
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001533 log1("Entering rebinding state");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001534 state = REBINDING;
Denis Vlasenko6de89942008-05-21 07:05:06 +00001535 /* fall right through */
Mike Frysinger7031f622006-05-08 03:20:50 +00001536 case REBINDING:
Denys Vlasenko219757f2009-10-08 23:05:46 +02001537 /* Switch to bcast receive */
1538 change_listen_mode(LISTEN_RAW);
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001539 /* Lease is *really* about to run out,
1540 * try to find DHCP server using broadcast */
Denis Vlasenko19903f02008-05-21 07:03:03 +00001541 if (timeout > 0) {
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001542 /* send a broadcast renew request */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001543 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
Denis Vlasenko19903f02008-05-21 07:03:03 +00001544 timeout >>= 1;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001545 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001546 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001547 /* Timed out, enter init state */
1548 bb_info_msg("Lease lost, entering init state");
1549 udhcp_run_script(NULL, "deconfig");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001550 state = INIT_SELECTING;
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001551 client_config.first_secs = 0; /* make secs field count from 0 */
Denis Vlasenko19903f02008-05-21 07:03:03 +00001552 /*timeout = 0; - already is */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001553 packet_num = 0;
1554 continue;
1555 /* case RELEASED: */
Mike Frysinger7031f622006-05-08 03:20:50 +00001556 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001557 /* yah, I know, *you* say it would never happen */
1558 timeout = INT_MAX;
1559 continue; /* back to main loop */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001560 } /* if select timed out */
1561
1562 /* select() didn't timeout, something happened */
1563
1564 /* Is it a signal? */
1565 /* note: udhcp_sp_read checks FD_ISSET before reading */
1566 switch (udhcp_sp_read(&rfds)) {
1567 case SIGUSR1:
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001568 client_config.first_secs = 0; /* make secs field count from 0 */
Vladislav Grishenko6464f152011-10-18 01:37:47 +02001569 already_waited_sec = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001570 perform_renew();
Vladislav Grishenko6464f152011-10-18 01:37:47 +02001571 if (state == RENEW_REQUESTED) {
1572 /* We might be either on the same network
1573 * (in which case renew might work),
1574 * or we might be on a completely different one
1575 * (in which case renew won't ever succeed).
1576 * For the second case, must make sure timeout
1577 * is not too big, or else we can send
1578 * futile renew requests for hours.
1579 * (Ab)use -A TIMEOUT value (usually 20 sec)
1580 * as a cap on the timeout.
1581 */
1582 if (timeout > tryagain_timeout)
1583 timeout = tryagain_timeout;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001584 goto case_RENEW_REQUESTED;
Vladislav Grishenko6464f152011-10-18 01:37:47 +02001585 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001586 /* Start things over */
1587 packet_num = 0;
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001588 /* Kill any timeouts, user wants this to hurry along */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001589 timeout = 0;
1590 continue;
1591 case SIGUSR2:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001592 perform_release(server_addr, requested_ip);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001593 timeout = INT_MAX;
1594 continue;
1595 case SIGTERM:
1596 bb_info_msg("Received SIGTERM");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001597 goto ret0;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001598 }
1599
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001600 /* Is it a packet? */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001601 if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
1602 continue; /* no */
Mike Frysinger7031f622006-05-08 03:20:50 +00001603
Denys Vlasenko4248c332009-06-26 23:23:16 +02001604 {
1605 int len;
1606
1607 /* A packet is ready, read it */
Mike Frysinger7031f622006-05-08 03:20:50 +00001608 if (listen_mode == LISTEN_KERNEL)
Denis Vlasenko6de89942008-05-21 07:05:06 +00001609 len = udhcp_recv_kernel_packet(&packet, sockfd);
Denis Vlasenkob76b9a42008-01-25 22:46:34 +00001610 else
Denis Vlasenko6de89942008-05-21 07:05:06 +00001611 len = udhcp_recv_raw_packet(&packet, sockfd);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001612 if (len == -1) {
1613 /* Error is severe, reopen socket */
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001614 bb_info_msg("Read error: %s, reopening socket", strerror(errno));
Denis Vlasenko6de89942008-05-21 07:05:06 +00001615 sleep(discover_timeout); /* 3 seconds by default */
1616 change_listen_mode(listen_mode); /* just close and reopen */
1617 }
Denis Vlasenkob2342912008-05-21 07:02:16 +00001618 /* If this packet will turn out to be unrelated/bogus,
1619 * we will go back and wait for next one.
1620 * Be sure timeout is properly decreased. */
Denis Vlasenko19903f02008-05-21 07:03:03 +00001621 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
Denis Vlasenko6de89942008-05-21 07:05:06 +00001622 if (len < 0)
1623 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001624 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001625
Denys Vlasenko4248c332009-06-26 23:23:16 +02001626 if (packet.xid != xid) {
1627 log1("xid %x (our is %x), ignoring packet",
1628 (unsigned)packet.xid, (unsigned)xid);
1629 continue;
1630 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001631
Denys Vlasenko4248c332009-06-26 23:23:16 +02001632 /* Ignore packets that aren't for us */
1633 if (packet.hlen != 6
Denys Vlasenkob3af65b2010-10-20 21:37:23 +02001634 || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
Denys Vlasenko4248c332009-06-26 23:23:16 +02001635 ) {
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001636//FIXME: need to also check that last 10 bytes are zero
Denys Vlasenko4248c332009-06-26 23:23:16 +02001637 log1("chaddr does not match, ignoring packet"); // log2?
1638 continue;
1639 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001640
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001641 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001642 if (message == NULL) {
1643 bb_error_msg("no message type option, ignoring packet");
1644 continue;
1645 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001646
Denys Vlasenko4248c332009-06-26 23:23:16 +02001647 switch (state) {
1648 case INIT_SELECTING:
Denys Vlasenko860491c2011-11-18 02:09:13 +01001649 /* Must be a DHCPOFFER */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001650 if (*message == DHCPOFFER) {
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001651 uint8_t *temp;
1652
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001653/* What exactly is server's IP? There are several values.
1654 * Example DHCP offer captured with tchdump:
1655 *
1656 * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1657 * BOOTP fields:
1658 * Your-IP 10.34.25.202
1659 * Server-IP 10.34.32.125 // "next server" IP
1660 * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
1661 * DHCP options:
1662 * DHCP-Message Option 53, length 1: Offer
1663 * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
1664 * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1665 *
1666 * We think that real server IP (one to use in renew/release)
1667 * is one in Server-ID option. But I am not 100% sure.
Denys Vlasenkoee320c62011-10-23 18:05:58 +02001668 * IP header's src and Gateway-IP (same in this example)
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001669 * might work too.
1670 * "Next server" and router are definitely wrong ones to use, though...
1671 */
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001672/* We used to ignore pcakets without DHCP_SERVER_ID.
1673 * I've got user reports from people who run "address-less" servers.
1674 * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
1675 * They say ISC DHCP client supports this case.
1676 */
1677 server_addr = 0;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001678 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001679 if (!temp) {
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001680 bb_error_msg("no server ID, using 0.0.0.0");
1681 } else {
1682 /* it IS unaligned sometimes, don't "optimize" */
1683 move_from_unaligned32(server_addr, temp);
Mike Frysinger7031f622006-05-08 03:20:50 +00001684 }
Denys Vlasenkob3af65b2010-10-20 21:37:23 +02001685 /*xid = packet.xid; - already is */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001686 requested_ip = packet.yiaddr;
1687
1688 /* enter requesting state */
1689 state = REQUESTING;
1690 timeout = 0;
1691 packet_num = 0;
1692 already_waited_sec = 0;
1693 }
1694 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001695 case REQUESTING:
1696 case RENEWING:
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001697 case RENEW_REQUESTED:
Denys Vlasenko4248c332009-06-26 23:23:16 +02001698 case REBINDING:
1699 if (*message == DHCPACK) {
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001700 uint32_t lease_seconds;
1701 struct in_addr temp_addr;
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001702 uint8_t *temp;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001703
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001704 temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001705 if (!temp) {
1706 bb_error_msg("no lease time with ACK, using 1 hour lease");
1707 lease_seconds = 60 * 60;
1708 } else {
1709 /* it IS unaligned sometimes, don't "optimize" */
1710 move_from_unaligned32(lease_seconds, temp);
1711 lease_seconds = ntohl(lease_seconds);
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001712 /* paranoia: must not be too small and not prone to overflows */
1713 if (lease_seconds < 0x10)
1714 lease_seconds = 0x10;
1715 if (lease_seconds >= 0x10000000)
1716 lease_seconds = 0x0fffffff;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001717 }
Denis Vlasenko223bc972007-11-22 00:58:49 +00001718#if ENABLE_FEATURE_UDHCPC_ARPING
Denys Vlasenko4248c332009-06-26 23:23:16 +02001719 if (opt & OPT_a) {
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001720/* RFC 2131 3.1 paragraph 5:
1721 * "The client receives the DHCPACK message with configuration
1722 * parameters. The client SHOULD perform a final check on the
1723 * parameters (e.g., ARP for allocated network address), and notes
1724 * the duration of the lease specified in the DHCPACK message. At this
1725 * point, the client is configured. If the client detects that the
1726 * address is already in use (e.g., through the use of ARP),
1727 * the client MUST send a DHCPDECLINE message to the server and restarts
1728 * the configuration process..." */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001729 if (!arpping(packet.yiaddr,
1730 NULL,
1731 (uint32_t) 0,
1732 client_config.client_mac,
Michel Stam9f412712014-10-30 11:59:04 +01001733 client_config.interface,
1734 arpping_ms)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001735 ) {
1736 bb_info_msg("Offered address is in use "
1737 "(got ARP reply), declining");
Denys Vlasenko860491c2011-11-18 02:09:13 +01001738 send_decline(/*xid,*/ server_addr, packet.yiaddr);
Denis Vlasenko223bc972007-11-22 00:58:49 +00001739
Denys Vlasenko4248c332009-06-26 23:23:16 +02001740 if (state != REQUESTING)
1741 udhcp_run_script(NULL, "deconfig");
1742 change_listen_mode(LISTEN_RAW);
1743 state = INIT_SELECTING;
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001744 client_config.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001745 requested_ip = 0;
1746 timeout = tryagain_timeout;
1747 packet_num = 0;
1748 already_waited_sec = 0;
1749 continue; /* back to main loop */
Denis Vlasenko223bc972007-11-22 00:58:49 +00001750 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001751 }
Denis Vlasenko223bc972007-11-22 00:58:49 +00001752#endif
Denys Vlasenko4248c332009-06-26 23:23:16 +02001753 /* enter bound state */
1754 timeout = lease_seconds / 2;
Denys Vlasenko60cb48c2013-01-14 15:57:44 +01001755 temp_addr.s_addr = packet.yiaddr;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001756 bb_info_msg("Lease of %s obtained, lease time %u",
1757 inet_ntoa(temp_addr), (unsigned)lease_seconds);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001758 requested_ip = packet.yiaddr;
Denys Vlasenko4abfc262009-07-19 04:35:16 +02001759 udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
Mike Frysinger7031f622006-05-08 03:20:50 +00001760
Denys Vlasenko4248c332009-06-26 23:23:16 +02001761 state = BOUND;
1762 change_listen_mode(LISTEN_NONE);
1763 if (opt & OPT_q) { /* quit after lease */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001764 goto ret0;
1765 }
Justin Maggardaa369e02009-08-13 01:26:17 +02001766 /* future renew failures should not exit (JM) */
1767 opt &= ~OPT_n;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001768#if BB_MMU /* NOMMU case backgrounded earlier */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001769 if (!(opt & OPT_f)) {
1770 client_background();
1771 /* do not background again! */
1772 opt = ((opt & ~OPT_b) | OPT_f);
1773 }
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001774#endif
Denys Vlasenko860491c2011-11-18 02:09:13 +01001775 /* make future renew packets use different xid */
1776 /* xid = random_xid(); ...but why bother? */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001777 already_waited_sec = 0;
1778 continue; /* back to main loop */
Mike Frysinger7031f622006-05-08 03:20:50 +00001779 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001780 if (*message == DHCPNAK) {
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001781 /* If network has more than one DHCP server,
1782 * "wrong" server can reply first, with a NAK.
1783 * Do not interpret it as a NAK from "our" server.
1784 */
1785 if (server_addr != 0) {
1786 uint32_t svid;
1787 uint8_t *temp;
1788
1789 temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
1790 if (!temp) {
1791 non_matching_svid:
1792 log1("%s with wrong server ID, ignoring packet",
1793 "Received DHCP NAK"
1794 );
1795 continue;
1796 }
1797 move_from_unaligned32(svid, temp);
1798 if (svid != server_addr)
1799 goto non_matching_svid;
1800 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001801 /* return to init state */
1802 bb_info_msg("Received DHCP NAK");
1803 udhcp_run_script(&packet, "nak");
1804 if (state != REQUESTING)
1805 udhcp_run_script(NULL, "deconfig");
1806 change_listen_mode(LISTEN_RAW);
1807 sleep(3); /* avoid excessive network traffic */
1808 state = INIT_SELECTING;
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001809 client_config.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001810 requested_ip = 0;
Denis Vlasenkob539c842007-11-29 08:17:45 +00001811 timeout = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001812 packet_num = 0;
1813 already_waited_sec = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001814 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001815 continue;
1816 /* case BOUND: - ignore all packets */
1817 /* case RELEASED: - ignore all packets */
Mike Frysinger7031f622006-05-08 03:20:50 +00001818 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001819 /* back to main loop */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001820 } /* for (;;) - main loop ends */
1821
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001822 ret0:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001823 if (opt & OPT_R) /* release on quit */
1824 perform_release(server_addr, requested_ip);
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001825 retval = 0;
1826 ret:
Denis Vlasenkob2342912008-05-21 07:02:16 +00001827 /*if (client_config.pidfile) - remove_pidfile has its own check */
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001828 remove_pidfile(client_config.pidfile);
1829 return retval;
Mike Frysinger7031f622006-05-08 03:20:50 +00001830}