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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 * Russ Dill <Russ.Dill@asu.edu> July 2001
5 *
Denys Vlasenko6b24d532010-03-22 13:42:13 +01006 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Mike Frysinger7031f622006-05-08 03:20:50 +000019 */
Denys Vlasenkof7683cd2016-11-23 18:54:59 +010020//applet:IF_UDHCPC(APPLET(udhcpc, BB_DIR_SBIN, BB_SUID_DROP))
21
22//kbuild:lib-$(CONFIG_UDHCPC) += common.o packet.o signalpipe.o socket.o
23//kbuild:lib-$(CONFIG_UDHCPC) += dhcpc.o
24//kbuild:lib-$(CONFIG_FEATURE_UDHCPC_ARPING) += arpping.o
25//kbuild:lib-$(CONFIG_FEATURE_UDHCP_RFC3397) += domain_codec.o
26
Denis Vlasenkoaf1c8432007-03-26 13:22:35 +000027#include <syslog.h>
Denis Vlasenko1caca342007-08-02 10:14:29 +000028/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
29#define WANT_PIDFILE 1
Mike Frysinger7031f622006-05-08 03:20:50 +000030#include "common.h"
31#include "dhcpd.h"
32#include "dhcpc.h"
Denis Vlasenko5a3395b2006-11-18 19:51:32 +000033
Dan Fandrichf533ec82011-06-10 05:17:59 +020034#include <netinet/if_ether.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010035#include <linux/filter.h>
Alexey Froloff3c62bba2012-09-17 16:02:44 +020036#include <linux/if_packet.h>
Denys Vlasenko6b24d532010-03-22 13:42:13 +010037
Denys Vlasenkof2bf20f2015-10-08 18:13:57 +020038#ifndef PACKET_AUXDATA
39# define PACKET_AUXDATA 8
40struct tpacket_auxdata {
41 uint32_t tp_status;
42 uint32_t tp_len;
43 uint32_t tp_snaplen;
44 uint16_t tp_mac;
45 uint16_t tp_net;
46 uint16_t tp_vlan_tci;
47 uint16_t tp_padding;
48};
49#endif
50
51
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +020052/* "struct client_data_t client_data" is in bb_common_bufsiz1 */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +000053
Mike Frysinger7031f622006-05-08 03:20:50 +000054
Keith Younge6bb8d32011-03-07 03:18:46 +010055#if ENABLE_LONG_OPTS
56static const char udhcpc_longopts[] ALIGN1 =
57 "clientid-none\0" No_argument "C"
58 "vendorclass\0" Required_argument "V"
59 "hostname\0" Required_argument "H"
60 "fqdn\0" Required_argument "F"
61 "interface\0" Required_argument "i"
62 "now\0" No_argument "n"
63 "pidfile\0" Required_argument "p"
64 "quit\0" No_argument "q"
65 "release\0" No_argument "R"
66 "request\0" Required_argument "r"
67 "script\0" Required_argument "s"
68 "timeout\0" Required_argument "T"
Keith Younge6bb8d32011-03-07 03:18:46 +010069 "retries\0" Required_argument "t"
70 "tryagain\0" Required_argument "A"
71 "syslog\0" No_argument "S"
72 "request-option\0" Required_argument "O"
73 "no-default-options\0" No_argument "o"
74 "foreground\0" No_argument "f"
Denys Vlasenkoed820cc2017-05-08 15:11:02 +020075 USE_FOR_MMU(
Keith Younge6bb8d32011-03-07 03:18:46 +010076 "background\0" No_argument "b"
Denys Vlasenkoed820cc2017-05-08 15:11:02 +020077 )
Keith Younge6bb8d32011-03-07 03:18:46 +010078 "broadcast\0" No_argument "B"
Michel Stam9f412712014-10-30 11:59:04 +010079 IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
Keith Younge6bb8d32011-03-07 03:18:46 +010080 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
81 ;
82#endif
83/* Must match getopt32 option string order */
84enum {
85 OPT_C = 1 << 0,
86 OPT_V = 1 << 1,
87 OPT_H = 1 << 2,
88 OPT_h = 1 << 3,
89 OPT_F = 1 << 4,
90 OPT_i = 1 << 5,
91 OPT_n = 1 << 6,
92 OPT_p = 1 << 7,
93 OPT_q = 1 << 8,
94 OPT_R = 1 << 9,
95 OPT_r = 1 << 10,
96 OPT_s = 1 << 11,
97 OPT_T = 1 << 12,
98 OPT_t = 1 << 13,
99 OPT_S = 1 << 14,
100 OPT_A = 1 << 15,
101 OPT_O = 1 << 16,
102 OPT_o = 1 << 17,
103 OPT_x = 1 << 18,
104 OPT_f = 1 << 19,
105 OPT_B = 1 << 20,
106/* The rest has variable bit positions, need to be clever */
107 OPTBIT_B = 20,
108 USE_FOR_MMU( OPTBIT_b,)
109 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
110 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
111 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
112 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
113 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
114};
115
116
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100117/*** Script execution code ***/
Martin Lewis9914d8b2020-08-04 17:27:16 -0500118struct dhcp_optitem {
119 unsigned len;
120 uint8_t code;
121 uint8_t malloced;
122 uint8_t *data;
123 char *env;
124};
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100125
126/* get a rough idea of how long an option will be (rounding up...) */
Denys Vlasenko3e134eb2016-04-22 18:09:21 +0200127static const uint8_t len_of_option_as_string[] ALIGN1 = {
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200128 [OPTION_IP ] = sizeof("255.255.255.255 "),
129 [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
130 [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
Denys Vlasenko352f79a2016-02-26 15:54:56 +0100131 [OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200132 [OPTION_STRING ] = 1,
Denys Vlasenkod2266d42012-04-22 03:37:01 +0200133 [OPTION_STRING_HOST ] = 1,
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100134#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200135 [OPTION_DNS_STRING ] = 1, /* unused */
136 /* Hmmm, this severely overestimates size if SIP_SERVERS option
137 * is in domain name form: N-byte option in binary form
138 * mallocs ~16*N bytes. But it is freed almost at once.
139 */
140 [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100141#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200142// [OPTION_BOOLEAN ] = sizeof("yes "),
143 [OPTION_U8 ] = sizeof("255 "),
144 [OPTION_U16 ] = sizeof("65535 "),
145// [OPTION_S16 ] = sizeof("-32768 "),
146 [OPTION_U32 ] = sizeof("4294967295 "),
147 [OPTION_S32 ] = sizeof("-2147483684 "),
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100148};
149
150/* note: ip is a pointer to an IP in network order, possibly misaliged */
151static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
152{
153 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
154}
155
156/* really simple implementation, just count the bits */
157static int mton(uint32_t mask)
158{
159 int i = 0;
160 mask = ntohl(mask); /* 111110000-like bit pattern */
161 while (mask) {
162 i++;
163 mask <<= 1;
164 }
165 return i;
166}
167
Denys Vlasenko85090c12014-06-16 00:17:00 +0200168#if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
Denys Vlasenko7280d202011-12-08 16:41:05 +0100169/* Check if a given name represents a valid DNS name */
170/* See RFC1035, 2.3.1 */
Martin Lewis726d0d12020-05-04 16:59:14 -0500171/* We don't need to be particularly anal. For example, allowing _, hyphen
172 * at the end, or leading and trailing dots would be ok, since it
173 * can't be used for attacks. (Leading hyphen can be, if someone uses cmd "$hostname"
174 * in the script: then hostname may be treated as an option)
175 */
Denys Vlasenko7280d202011-12-08 16:41:05 +0100176static int good_hostname(const char *name)
177{
Martin Lewis726d0d12020-05-04 16:59:14 -0500178 if (*name == '-') /* Can't start with '-' */
179 return 0;
Denys Vlasenko7280d202011-12-08 16:41:05 +0100180
Martin Lewis726d0d12020-05-04 16:59:14 -0500181 while (*name) {
182 unsigned char ch = *name++;
183 if (!isalnum(ch))
184 /* DNS allows only '-', but we are more permissive */
185 if (ch != '-' && ch != '_' && ch != '.')
186 return 0;
187 // TODO: do we want to validate lengths against NS_MAXLABEL and NS_MAXDNAME?
Denys Vlasenko7280d202011-12-08 16:41:05 +0100188 }
Martin Lewis726d0d12020-05-04 16:59:14 -0500189 return 1;
Denys Vlasenko7280d202011-12-08 16:41:05 +0100190}
Denys Vlasenko85090c12014-06-16 00:17:00 +0200191#else
192# define good_hostname(name) 1
193#endif
Denys Vlasenko7280d202011-12-08 16:41:05 +0100194
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100195/* Create "opt_name=opt_value" string */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500196static NOINLINE char *xmalloc_optname_optval(const struct dhcp_optitem *opt_item, const struct dhcp_optflag *optflag, const char *opt_name)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100197{
198 unsigned upper_length;
199 int len, type, optlen;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100200 char *dest, *ret;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500201 uint8_t *option;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100202
Martin Lewis9914d8b2020-08-04 17:27:16 -0500203 option = opt_item->data;
204 len = opt_item->len;
Denys Vlasenkoc03602b2010-04-04 15:28:49 +0200205 type = optflag->flags & OPTION_TYPE_MASK;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100206 optlen = dhcp_option_lengths[type];
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200207 upper_length = len_of_option_as_string[type]
Denys Vlasenko352f79a2016-02-26 15:54:56 +0100208 * ((unsigned)(len + optlen) / (unsigned)optlen);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100209
210 dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
211 dest += sprintf(ret, "%s=", opt_name);
212
213 while (len >= optlen) {
214 switch (type) {
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200215 case OPTION_IP:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100216 case OPTION_IP_PAIR:
217 dest += sprint_nip(dest, "", option);
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500218 if (type == OPTION_IP_PAIR)
219 dest += sprint_nip(dest, "/", option + 4);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100220 break;
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100221// case OPTION_BOOLEAN:
222// dest += sprintf(dest, *option ? "yes" : "no");
223// break;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100224 case OPTION_U8:
225 dest += sprintf(dest, "%u", *option);
226 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200227// case OPTION_S16:
228 case OPTION_U16: {
229 uint16_t val_u16;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100230 move_from_unaligned16(val_u16, option);
231 dest += sprintf(dest, "%u", ntohs(val_u16));
232 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200233 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100234 case OPTION_S32:
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200235 case OPTION_U32: {
236 uint32_t val_u32;
237 move_from_unaligned32(val_u32, option);
238 dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100239 break;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200240 }
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200241 /* Note: options which use 'return' instead of 'break'
242 * (for example, OPTION_STRING) skip the code which handles
243 * the case of list of options.
244 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100245 case OPTION_STRING:
Denys Vlasenko7280d202011-12-08 16:41:05 +0100246 case OPTION_STRING_HOST:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100247 memcpy(dest, option, len);
248 dest[len] = '\0';
Denys Vlasenko02cf1492018-08-01 13:36:36 +0200249//TODO: it appears option 15 DHCP_DOMAIN_NAME is often abused
250//by DHCP admins to contain a space-separated list of domains,
251//not one domain name (presumably, to work as list of search domains,
252//instead of using proper option 119 DHCP_DOMAIN_SEARCH).
253//Currently, good_hostname() balks on strings containing spaces.
254//Do we need to allow it? Only for DHCP_DOMAIN_NAME option?
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
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500321 * (2nd condition needs 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;
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500335 len -= 1 + 1 + 16;
336 *dest++ = ' ';
337 /* 6rdBRIPv4Address(es), use common IPv4 logic to process them */
338 type = OPTION_IP;
339 optlen = 4;
340 continue;
Denys Vlasenko1f56e512011-10-19 22:40:35 +0200341 }
342
343 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100344#if ENABLE_FEATURE_UDHCP_RFC3397
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200345 case OPTION_DNS_STRING:
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100346 /* unpack option into dest; use ret for prefix (i.e., "optname=") */
347 dest = dname_dec(option, len, ret);
348 if (dest) {
349 free(ret);
350 return dest;
351 }
352 /* error. return "optname=" string */
353 return ret;
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200354 case OPTION_SIP_SERVERS:
355 /* Option binary format:
356 * type: byte
357 * type=0: domain names, dns-compressed
358 * type=1: IP addrs
359 */
360 option++;
361 len--;
Martin Lewisd30d1eb2020-06-09 16:59:54 -0500362 if (option[-1] == 1) {
363 /* use common IPv4 logic to process IP addrs */
364 type = OPTION_IP;
365 optlen = 4;
366 continue;
367 }
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200368 if (option[-1] == 0) {
369 dest = dname_dec(option, len, ret);
370 if (dest) {
371 free(ret);
372 return dest;
373 }
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200374 }
375 return ret;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100376#endif
Denys Vlasenko243ddcb2010-04-03 17:34:52 +0200377 } /* switch */
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200378
379 /* If we are here, try to format any remaining data
380 * in the option as another, similarly-formatted option
381 */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100382 option += optlen;
383 len -= optlen;
Vladislav Grishenkoad8def22010-10-17 12:27:50 +0200384// TODO: it can be a list only if (optflag->flags & OPTION_LIST).
385// Should we bail out/warn if we see multi-ip option which is
386// not allowed to be such (for example, DHCP_BROADCAST)? -
Denys Vlasenkocd4d78f2011-10-20 13:21:55 +0200387 if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100388 break;
389 *dest++ = ' ';
390 *dest = '\0';
Denys Vlasenko1dff6722011-10-20 12:29:18 +0200391 } /* while */
392
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100393 return ret;
394}
395
Martin Lewis9914d8b2020-08-04 17:27:16 -0500396static void optitem_unset_env_and_free(void *item)
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100397{
Martin Lewis9914d8b2020-08-04 17:27:16 -0500398 struct dhcp_optitem *opt_item = item;
399 bb_unsetenv_and_free(opt_item->env);
400 if (opt_item->malloced)
401 free(opt_item->data);
402 free(opt_item);
403}
404
405/* Used by static options (interface, siaddr, etc) */
406static void putenvp(char *new_opt)
407{
408 struct dhcp_optitem *opt_item;
409
410 opt_item = xzalloc(sizeof(*opt_item));
411 /* opt_item->code = 0, so it won't appear in concat_option's lookup */
412 /* opt_item->malloced = 0 */
413 /* opt_item->data = NULL */
414 opt_item->env = new_opt;
415 llist_add_to(&client_data.envp, opt_item);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500416 log2(" %s", new_opt);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500417 putenv(new_opt);
418}
419
420/* Support RFC3396 Long Encoded Options */
421static struct dhcp_optitem *concat_option(uint8_t *data, uint8_t len, uint8_t code)
422{
423 llist_t *item;
424 struct dhcp_optitem *opt_item;
425
426 /* Check if an option with the code already exists.
427 * A possible optimization is to create a bitmap of all existing options in the packet,
428 * and iterate over the option list only if they exist.
429 * This will result in bigger code, and because dhcp packets don't have too many options it
430 * shouldn't have a big impact on performance.
431 */
432 for (item = client_data.envp; item != NULL; item = item->link) {
433 opt_item = (struct dhcp_optitem *)item->data;
434 if (opt_item->code == code) {
435 /* This option was seen already, concatenate */
436 uint8_t *new_data;
437
438 new_data = xmalloc(len + opt_item->len);
439 memcpy(
440 mempcpy(new_data, opt_item->data, opt_item->len),
441 data, len
442 );
443 opt_item->len += len;
444 if (opt_item->malloced)
445 free(opt_item->data);
446 opt_item->malloced = 1;
447 opt_item->data = new_data;
448 return opt_item;
449 }
450 }
451
452 /* This is a new option, add a new dhcp_optitem to the list */
453 opt_item = xzalloc(sizeof(*opt_item));
454 opt_item->code = code;
455 /* opt_item->malloced = 0 */
456 opt_item->data = data;
457 opt_item->len = len;
458 llist_add_to(&client_data.envp, opt_item);
459 return opt_item;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500460}
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100461
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500462static const char* get_optname(uint8_t code, const struct dhcp_optflag **dh)
463{
464 /* Find the option:
465 * dhcp_optflags is sorted so we stop searching when dh->code >= code, which is faster
466 * than iterating over the entire array.
467 * Options which don't have a match in dhcp_option_strings[], e.g DHCP_REQUESTED_IP,
468 * are located after the sorted array, so these entries will never be reached
469 * and they'll count as unknown options.
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200470 */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500471 for (*dh = dhcp_optflags; (*dh)->code && (*dh)->code < code; (*dh)++)
Martin Lewis9914d8b2020-08-04 17:27:16 -0500472 continue;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100473
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500474 if ((*dh)->code == code)
475 return nth_string(dhcp_option_strings, (*dh - dhcp_optflags));
476
477 return NULL;
478}
479
480/* put all the parameters into the environment */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500481static void fill_envp(struct dhcp_packet *packet)
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500482{
483 uint8_t *optptr;
484 struct dhcp_scan_state scan_state;
485 char *new_opt;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500486
Martin Lewis9914d8b2020-08-04 17:27:16 -0500487 putenvp(xasprintf("interface=%s", client_data.interface));
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100488
Denys Vlasenkob7d19cc2010-05-30 23:41:23 +0200489 if (!packet)
Martin Lewis9914d8b2020-08-04 17:27:16 -0500490 return;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100491
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500492 init_scan_state(packet, &scan_state);
493
494 /* Iterate over the packet options.
495 * Handle each option based on whether it's an unknown / known option.
Martin Lewis9914d8b2020-08-04 17:27:16 -0500496 * Long options are supported in compliance with RFC 3396.
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500497 */
498 while ((optptr = udhcp_scan_options(packet, &scan_state)) != NULL) {
499 const struct dhcp_optflag *dh;
500 const char *opt_name;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500501 struct dhcp_optitem *opt_item;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500502 uint8_t code = optptr[OPT_CODE];
503 uint8_t len = optptr[OPT_LEN];
504 uint8_t *data = optptr + OPT_DATA;
505
Martin Lewis9914d8b2020-08-04 17:27:16 -0500506 opt_item = concat_option(data, len, code);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500507 opt_name = get_optname(code, &dh);
508 if (opt_name) {
Martin Lewis9914d8b2020-08-04 17:27:16 -0500509 new_opt = xmalloc_optname_optval(opt_item, dh, opt_name);
510 if (opt_item->code == DHCP_SUBNET && opt_item->len == 4) {
511 /* Generate extra envvar for DHCP_SUBNET, $mask */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500512 uint32_t subnet;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500513 move_from_unaligned32(subnet, opt_item->data);
514 putenvp(xasprintf("mask=%u", mton(subnet)));
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500515 }
516 } else {
517 unsigned ofs;
Martin Lewis9914d8b2020-08-04 17:27:16 -0500518 new_opt = xmalloc(sizeof("optNNN=") + 1 + opt_item->len*2);
519 ofs = sprintf(new_opt, "opt%u=", opt_item->code);
520 bin2hex(new_opt + ofs, (char *)opt_item->data, opt_item->len)[0] = '\0';
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500521 }
Martin Lewis9914d8b2020-08-04 17:27:16 -0500522 log2(" %s", new_opt);
523 putenv(new_opt);
524 /* putenv will replace the existing environment variable in case of a duplicate.
525 * Free the previous occurrence (NULL if it's the first one).
526 */
527 free(opt_item->env);
528 opt_item->env = new_opt;
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500529 }
530
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200531 /* Export BOOTP fields. Fields we don't (yet?) export:
532 * uint8_t op; // always BOOTREPLY
533 * uint8_t htype; // hardware address type. 1 = 10mb ethernet
534 * uint8_t hlen; // hardware address length
535 * uint8_t hops; // used by relay agents only
536 * uint32_t xid;
537 * uint16_t secs; // elapsed since client began acquisition/renewal
538 * uint16_t flags; // only one flag so far: bcast. Never set by server
539 * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
Brian Foleyf9beeb22016-10-25 14:20:55 +0200540 * // if during renew server wants to give us different IP?)
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200541 * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200542 */
543 /* Most important one: yiaddr as $ip */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500544 new_opt = xmalloc(sizeof("ip=255.255.255.255"));
545 sprint_nip(new_opt, "ip=", (uint8_t *) &packet->yiaddr);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500546 putenvp(new_opt);
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500547
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200548 if (packet->siaddr_nip) {
549 /* IP address of next server to use in bootstrap */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500550 new_opt = xmalloc(sizeof("siaddr=255.255.255.255"));
551 sprint_nip(new_opt, "siaddr=", (uint8_t *) &packet->siaddr_nip);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500552 putenvp(new_opt);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200553 }
Martin Lewisd378fa12019-06-10 17:06:17 +0200554 if (packet->gateway_nip) {
Denys Vlasenko84d38502019-06-13 10:02:03 +0200555 /* IP address of DHCP relay agent */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500556 new_opt = xmalloc(sizeof("giaddr=255.255.255.255"));
557 sprint_nip(new_opt, "giaddr=", (uint8_t *) &packet->gateway_nip);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500558 putenvp(new_opt);
Martin Lewisd378fa12019-06-10 17:06:17 +0200559 }
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500560 if (!(scan_state.overload & FILE_FIELD) && packet->file[0]) {
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200561 /* watch out for invalid packets */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500562 new_opt = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500563 putenvp(new_opt);
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200564 }
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500565 if (!(scan_state.overload & SNAME_FIELD) && packet->sname[0]) {
Denys Vlasenkofbca0c62011-10-20 14:24:18 +0200566 /* watch out for invalid packets */
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500567 new_opt = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
Martin Lewis9914d8b2020-08-04 17:27:16 -0500568 putenvp(new_opt);
Nigel Hathawayc37d4c62011-04-26 02:38:29 +0200569 }
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100570}
571
572/* Call a script with a par file and env vars */
573static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
574{
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100575 char *argv[3];
576
Martin Lewis9914d8b2020-08-04 17:27:16 -0500577 fill_envp(packet);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100578
579 /* call script */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200580 log1("executing %s %s", client_data.script, name);
581 argv[0] = (char*) client_data.script;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100582 argv[1] = (char*) name;
583 argv[2] = NULL;
584 spawn_and_wait(argv);
585
Martin Lewis1f86ecb2020-06-23 15:25:09 -0500586 /* Free all allocated environment variables */
Martin Lewis9914d8b2020-08-04 17:27:16 -0500587 llist_free(client_data.envp, optitem_unset_env_and_free);
588 client_data.envp = NULL;
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100589}
590
591
592/*** Sending/receiving packets ***/
593
Denys Vlasenko8d114452010-03-22 13:44:09 +0100594static ALWAYS_INLINE uint32_t random_xid(void)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100595{
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100596 return rand();
597}
598
599/* Initialize the packet with the proper defaults */
600static void init_packet(struct dhcp_packet *packet, char type)
601{
Denys Vlasenko11e024a2019-09-24 14:01:00 +0200602 unsigned secs;
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100603
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200604 /* Fill in: op, htype, hlen, cookie fields; message type option: */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100605 udhcp_init_header(packet, type);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200606
607 packet->xid = random_xid();
608
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200609 client_data.last_secs = monotonic_sec();
610 if (client_data.first_secs == 0)
611 client_data.first_secs = client_data.last_secs;
612 secs = client_data.last_secs - client_data.first_secs;
Denys Vlasenko11e024a2019-09-24 14:01:00 +0200613 packet->secs = (secs < 0xffff) ? htons(secs) : 0xffff;
Denys Vlasenko9ac55962011-03-12 05:37:54 +0100614
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200615 memcpy(packet->chaddr, client_data.client_mac, 6);
616 if (client_data.clientid)
617 udhcp_add_binary_option(packet, client_data.clientid);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100618}
619
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100620static void add_client_options(struct dhcp_packet *packet)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100621{
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200622 int i, end, len;
623
624 udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200625
Denys Vlasenko7724c762010-03-26 09:32:09 +0100626 /* Add a "param req" option with the list of options we'd like to have
Denys Vlasenkoa8f6b992010-03-26 08:35:24 +0100627 * from stubborn DHCP servers. Pull the data from the struct in common.c.
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100628 * No bounds checking because it goes towards the head of the packet. */
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200629 end = udhcp_end_option(packet->options);
630 len = 0;
Denys Vlasenko293c9452012-07-27 13:25:07 +0200631 for (i = 1; i < DHCP_END; i++) {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200632 if (client_data.opt_mask[i >> 3] & (1 << (i & 7))) {
Denys Vlasenko293c9452012-07-27 13:25:07 +0200633 packet->options[end + OPT_DATA + len] = i;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100634 len++;
635 }
636 }
637 if (len) {
638 packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
639 packet->options[end + OPT_LEN] = len;
640 packet->options[end + OPT_DATA + len] = DHCP_END;
641 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100642
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200643 if (client_data.vendorclass)
644 udhcp_add_binary_option(packet, client_data.vendorclass);
645 if (client_data.hostname)
646 udhcp_add_binary_option(packet, client_data.hostname);
647 if (client_data.fqdn)
648 udhcp_add_binary_option(packet, client_data.fqdn);
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200649
Keith Younge6bb8d32011-03-07 03:18:46 +0100650 /* Request broadcast replies if we have no IP addr */
651 if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
652 packet->flags |= htons(BROADCAST_FLAG);
653
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100654 /* Add -x options if any */
655 {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200656 struct option_set *curr = client_data.options;
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100657 while (curr) {
Denys Vlasenko7724c762010-03-26 09:32:09 +0100658 udhcp_add_binary_option(packet, curr->data);
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100659 curr = curr->next;
660 }
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200661// if (client_data.sname)
662// strncpy((char*)packet->sname, client_data.sname, sizeof(packet->sname) - 1);
663// if (client_data.boot_file)
664// strncpy((char*)packet->file, client_data.boot_file, sizeof(packet->file) - 1);
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100665 }
Denys Vlasenko2017d482011-11-05 01:24:14 +0100666
667 // This will be needed if we remove -V VENDOR_STR in favor of
668 // -x vendor:VENDOR_STR
669 //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
670 // /* not set, set the default vendor ID */
671 // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100672}
673
674/* RFC 2131
675 * 4.4.4 Use of broadcast and unicast
676 *
677 * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
678 * messages, unless the client knows the address of a DHCP server.
679 * The client unicasts DHCPRELEASE messages to the server. Because
680 * the client is declining the use of the IP address supplied by the server,
681 * the client broadcasts DHCPDECLINE messages.
682 *
683 * When the DHCP client knows the address of a DHCP server, in either
684 * INIT or REBOOTING state, the client may use that address
685 * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
686 * The client may also use unicast to send DHCPINFORM messages
687 * to a known DHCP server. If the client receives no response to DHCP
688 * messages sent to the IP address of a known DHCP server, the DHCP
689 * client reverts to using the IP broadcast address.
690 */
691
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200692static int raw_bcast_from_client_data_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100693{
694 return udhcp_send_raw_packet(packet,
Hans Dedeckerabe8f752016-02-18 12:27:07 +0100695 /*src*/ src_nip, CLIENT_PORT,
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100696 /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200697 client_data.ifindex);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100698}
699
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100700static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
701{
Denys Vlasenko148788e2018-06-21 17:36:22 +0200702 if (server)
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100703 return udhcp_send_kernel_packet(packet,
704 ciaddr, CLIENT_PORT,
Michal Kaziorb8176992020-12-15 09:53:40 +0000705 server, SERVER_PORT,
706 client_data.interface);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200707 return raw_bcast_from_client_data_ifindex(packet, ciaddr);
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100708}
709
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100710/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200711/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200712static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100713{
714 struct dhcp_packet packet;
715
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200716 /* Fill in: op, htype, hlen, cookie, chaddr fields,
717 * random xid field (we override it below),
718 * client-id option (unless -C), message type option:
719 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100720 init_packet(&packet, DHCPDISCOVER);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200721
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100722 packet.xid = xid;
723 if (requested)
Denys Vlasenko7724c762010-03-26 09:32:09 +0100724 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200725
726 /* Add options: maxsize,
727 * optionally: hostname, fqdn, vendorclass,
728 * "param req" option according to -O, options specified with -x
729 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100730 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100731
Denys Vlasenko64483322021-02-20 18:09:54 +0100732 bb_simple_info_msg("broadcasting discover");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200733 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100734}
735
736/* Broadcast a DHCP request message */
737/* RFC 2131 3.1 paragraph 3:
738 * "The client _broadcasts_ a DHCPREQUEST message..."
739 */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200740/* NOINLINE: limit stack usage in caller */
Denys Vlasenkoc72c1d72010-10-20 22:08:16 +0200741static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100742{
743 struct dhcp_packet packet;
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +0200744 struct in_addr temp_addr;
Denys Vlasenko64483322021-02-20 18:09:54 +0100745 char server_str[sizeof("255.255.255.255")];
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100746
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200747/*
748 * RFC 2131 4.3.2 DHCPREQUEST message
749 * ...
750 * If the DHCPREQUEST message contains a 'server identifier'
751 * option, the message is in response to a DHCPOFFER message.
752 * Otherwise, the message is a request to verify or extend an
753 * existing lease. If the client uses a 'client identifier'
754 * in a DHCPREQUEST message, it MUST use that same 'client identifier'
755 * in all subsequent messages. If the client included a list
756 * of requested parameters in a DHCPDISCOVER message, it MUST
757 * include that list in all subsequent messages.
758 */
759 /* Fill in: op, htype, hlen, cookie, chaddr fields,
760 * random xid field (we override it below),
761 * client-id option (unless -C), message type option:
762 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100763 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200764
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100765 packet.xid = xid;
Denys Vlasenko7724c762010-03-26 09:32:09 +0100766 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200767
Denys Vlasenko7724c762010-03-26 09:32:09 +0100768 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200769
770 /* Add options: maxsize,
771 * optionally: hostname, fqdn, vendorclass,
772 * "param req" option according to -O, and options specified with -x
773 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100774 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100775
Denys Vlasenko64483322021-02-20 18:09:54 +0100776 temp_addr.s_addr = server;
777 strcpy(server_str, inet_ntoa(temp_addr));
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +0200778 temp_addr.s_addr = requested;
Denys Vlasenko64483322021-02-20 18:09:54 +0100779 bb_info_msg("broadcasting select for %s, server %s",
780 inet_ntoa(temp_addr),
781 server_str
782 );
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200783 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100784}
785
786/* Unicast or broadcast a DHCP renew message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200787/* NOINLINE: limit stack usage in caller */
788static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100789{
790 struct dhcp_packet packet;
791
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200792/*
793 * RFC 2131 4.3.2 DHCPREQUEST message
794 * ...
795 * DHCPREQUEST generated during RENEWING state:
796 *
797 * 'server identifier' MUST NOT be filled in, 'requested IP address'
798 * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
799 * client's IP address. In this situation, the client is completely
800 * configured, and is trying to extend its lease. This message will
801 * be unicast, so no relay agents will be involved in its
802 * transmission. Because 'giaddr' is therefore not filled in, the
803 * DHCP server will trust the value in 'ciaddr', and use it when
804 * replying to the client.
805 */
806 /* Fill in: op, htype, hlen, cookie, chaddr fields,
807 * random xid field (we override it below),
808 * client-id option (unless -C), message type option:
809 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100810 init_packet(&packet, DHCPREQUEST);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200811
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100812 packet.xid = xid;
813 packet.ciaddr = ciaddr;
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200814
815 /* Add options: maxsize,
816 * optionally: hostname, fqdn, vendorclass,
817 * "param req" option according to -O, and options specified with -x
818 */
Denys Vlasenko7e6add12010-03-25 20:32:38 +0100819 add_client_options(&packet);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100820
Denys Vlasenko64483322021-02-20 18:09:54 +0100821 if (server) {
822 struct in_addr temp_addr;
823 temp_addr.s_addr = server;
824 bb_info_msg("sending renew to server %s", inet_ntoa(temp_addr));
825 } else {
826 bb_simple_info_msg("broadcasting renew");
827 }
828
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100829 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100830}
831
832#if ENABLE_FEATURE_UDHCPC_ARPING
833/* Broadcast a DHCP decline message */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200834/* NOINLINE: limit stack usage in caller */
Denys Vlasenko860491c2011-11-18 02:09:13 +0100835static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100836{
837 struct dhcp_packet packet;
838
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200839 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
840 * client-id option (unless -C), message type option:
841 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100842 init_packet(&packet, DHCPDECLINE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200843
Denys Vlasenko860491c2011-11-18 02:09:13 +0100844#if 0
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200845 /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
846 * but in case the server is buggy and wants DHCPDECLINE's xid
847 * to match the xid which started entire handshake,
848 * we use the same xid we used in initial DHCPDISCOVER:
849 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100850 packet.xid = xid;
Denys Vlasenko860491c2011-11-18 02:09:13 +0100851#endif
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200852 /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
Denys Vlasenko7724c762010-03-26 09:32:09 +0100853 udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200854
Denys Vlasenko7724c762010-03-26 09:32:09 +0100855 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100856
Denys Vlasenko64483322021-02-20 18:09:54 +0100857 bb_simple_info_msg("broadcasting decline");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200858 return raw_bcast_from_client_data_ifindex(&packet, INADDR_ANY);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100859}
860#endif
861
862/* Unicast a DHCP release message */
Denys Vlasenko9d05ad02018-11-03 23:34:03 +0100863static
864ALWAYS_INLINE /* one caller, help compiler to use this fact */
865int send_release(uint32_t server, uint32_t ciaddr)
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100866{
867 struct dhcp_packet packet;
868
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200869 /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
870 * client-id option (unless -C), message type option:
871 */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100872 init_packet(&packet, DHCPRELEASE);
Denys Vlasenkob3af65b2010-10-20 21:37:23 +0200873
874 /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100875 packet.ciaddr = ciaddr;
876
Denys Vlasenko7724c762010-03-26 09:32:09 +0100877 udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100878
James Byrne253c4e72019-04-12 17:01:51 +0000879 bb_info_msg("sending %s", "release");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +0100880 /* Note: normally we unicast here since "server" is not zero.
881 * However, there _are_ people who run "address-less" DHCP servers,
882 * and reportedly ISC dhcp client and Windows allow that.
883 */
884 return bcast_or_ucast(&packet, ciaddr, server);
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100885}
886
887/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
Denys Vlasenko0bb35e12010-10-21 12:33:10 +0200888/* NOINLINE: limit stack usage in caller */
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100889static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
890{
891 int bytes;
892 struct ip_udp_dhcp_packet packet;
893 uint16_t check;
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200894 unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
895 struct iovec iov;
896 struct msghdr msg;
897 struct cmsghdr *cmsg;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100898
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200899 /* used to use just safe_read(fd, &packet, sizeof(packet))
900 * but we need to check for TP_STATUS_CSUMNOTREADY :(
901 */
902 iov.iov_base = &packet;
903 iov.iov_len = sizeof(packet);
904 memset(&msg, 0, sizeof(msg));
905 msg.msg_iov = &iov;
906 msg.msg_iovlen = 1;
907 msg.msg_control = cmsgbuf;
908 msg.msg_controllen = sizeof(cmsgbuf);
909 for (;;) {
910 bytes = recvmsg(fd, &msg, 0);
911 if (bytes < 0) {
912 if (errno == EINTR)
913 continue;
James Byrne69374872019-07-02 11:35:03 +0200914 log1s("packet read error, ignoring");
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200915 /* NB: possible down interface, etc. Caller should pause. */
916 return bytes; /* returns -1 */
917 }
918 break;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100919 }
920
921 if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
James Byrne69374872019-07-02 11:35:03 +0200922 log1s("packet is too short, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100923 return -2;
924 }
925
926 if (bytes < ntohs(packet.ip.tot_len)) {
927 /* packet is bigger than sizeof(packet), we did partial read */
James Byrne69374872019-07-02 11:35:03 +0200928 log1s("oversized packet, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100929 return -2;
930 }
931
932 /* ignore any extra garbage bytes */
933 bytes = ntohs(packet.ip.tot_len);
934
935 /* make sure its the right packet for us, and that it passes sanity checks */
Denys Vlasenko7981d792011-10-20 10:34:05 +0200936 if (packet.ip.protocol != IPPROTO_UDP
937 || packet.ip.version != IPVERSION
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100938 || packet.ip.ihl != (sizeof(packet.ip) >> 2)
939 || packet.udp.dest != htons(CLIENT_PORT)
940 /* || bytes > (int) sizeof(packet) - can't happen */
941 || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
942 ) {
James Byrne69374872019-07-02 11:35:03 +0200943 log1s("unrelated/bogus packet, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100944 return -2;
945 }
946
947 /* verify IP checksum */
948 check = packet.ip.check;
949 packet.ip.check = 0;
Denys Vlasenko4a0eb032020-10-01 03:07:22 +0200950 if (check != inet_cksum(&packet.ip, sizeof(packet.ip))) {
James Byrne69374872019-07-02 11:35:03 +0200951 log1s("bad IP header checksum, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100952 return -2;
953 }
954
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200955 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
956 if (cmsg->cmsg_level == SOL_PACKET
957 && cmsg->cmsg_type == PACKET_AUXDATA
958 ) {
959 /* some VMs don't checksum UDP and TCP data
960 * they send to the same physical machine,
961 * here we detect this case:
962 */
963 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
964 if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
965 goto skip_udp_sum_check;
966 }
967 }
968
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100969 /* verify UDP checksum. IP header has to be modified for this */
970 memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
971 /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
972 packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
973 check = packet.udp.check;
974 packet.udp.check = 0;
Denys Vlasenko4a0eb032020-10-01 03:07:22 +0200975 if (check && check != inet_cksum(&packet, bytes)) {
James Byrne69374872019-07-02 11:35:03 +0200976 log1s("packet with bad UDP checksum received, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100977 return -2;
978 }
Alexey Froloff3c62bba2012-09-17 16:02:44 +0200979 skip_udp_sum_check:
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100980
Denys Vlasenko7981d792011-10-20 10:34:05 +0200981 if (packet.data.cookie != htonl(DHCP_MAGIC)) {
James Byrne69374872019-07-02 11:35:03 +0200982 bb_simple_info_msg("packet with bad magic, ignoring");
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100983 return -2;
984 }
Denys Vlasenko7981d792011-10-20 10:34:05 +0200985
Denys Vlasenko8f2e99c2016-03-30 18:41:23 +0200986 log1("received %s", "a packet");
Denys Vlasenko7981d792011-10-20 10:34:05 +0200987 udhcp_dump_packet(&packet.data);
988
989 bytes -= sizeof(packet.ip) + sizeof(packet.udp);
990 memcpy(dhcp_pkt, &packet.data, bytes);
991 return bytes;
Denys Vlasenko501e35c2010-03-22 13:43:12 +0100992}
Denys Vlasenko6b24d532010-03-22 13:42:13 +0100993
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100994
995/*** Main ***/
996
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +0200997/* Values for client_data.listen_mode */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +0100998#define LISTEN_NONE 0
999#define LISTEN_KERNEL 1
1000#define LISTEN_RAW 2
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001001
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001002/* Values for client_data.state */
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001003/* initial state: (re)start DHCP negotiation */
1004#define INIT_SELECTING 0
1005/* discover was sent, DHCPOFFER reply received */
1006#define REQUESTING 1
1007/* select/renew was sent, DHCPACK reply received */
1008#define BOUND 2
1009/* half of lease passed, want to renew it by sending unicast renew requests */
1010#define RENEWING 3
1011/* renew requests were not answered, lease is almost over, send broadcast renew */
1012#define REBINDING 4
1013/* manually requested renew (SIGUSR1) */
1014#define RENEW_REQUESTED 5
1015/* release, possibly manually requested (SIGUSR2) */
1016#define RELEASED 6
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001017
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001018static int udhcp_raw_socket(int ifindex)
1019{
1020 int fd;
1021 struct sockaddr_ll sock;
1022
Denys Vlasenko168f0ef2017-07-21 12:04:22 +02001023 log2("opening raw socket on ifindex %d", ifindex);
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001024
1025 fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
Denys Vlasenko744ee5d2014-02-07 17:38:52 +01001026 /* ^^^^^
1027 * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
1028 * ETH_P_IP: want to receive only packets with IPv4 eth type
1029 */
Denys Vlasenko6eb6e6a2019-05-31 23:51:07 +02001030 log3("got raw socket fd %d", fd);
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001031
Denys Vlasenko2b9acc62017-09-29 14:09:02 +02001032 memset(&sock, 0, sizeof(sock)); /* let's be deterministic */
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001033 sock.sll_family = AF_PACKET;
1034 sock.sll_protocol = htons(ETH_P_IP);
1035 sock.sll_ifindex = ifindex;
Denys Vlasenko2b9acc62017-09-29 14:09:02 +02001036 /*sock.sll_hatype = ARPHRD_???;*/
1037 /*sock.sll_pkttype = PACKET_???;*/
1038 /*sock.sll_halen = ???;*/
1039 /*sock.sll_addr[8] = ???;*/
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001040 xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
1041
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001042#if 0 /* Several users reported breakage when BPF filter is used */
Vladislav Grishenko713e6d72011-02-14 04:50:30 +01001043 if (CLIENT_PORT == 68) {
1044 /* Use only if standard port is in use */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001045 /*
1046 * I've selected not to see LL header, so BPF doesn't see it, too.
1047 * The filter may also pass non-IP and non-ARP packets, but we do
1048 * a more complete check when receiving the message in userspace.
1049 *
1050 * and filter shamelessly stolen from:
1051 *
1052 * http://www.flamewarmaster.de/software/dhcpclient/
1053 *
1054 * There are a few other interesting ideas on that page (look under
1055 * "Motivation"). Use of netlink events is most interesting. Think
1056 * of various network servers listening for events and reconfiguring.
1057 * That would obsolete sending HUP signals and/or make use of restarts.
1058 *
1059 * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
1060 * License: GPL v2.
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001061 */
1062 static const struct sock_filter filter_instr[] = {
1063 /* load 9th byte (protocol) */
1064 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
1065 /* jump to L1 if it is IPPROTO_UDP, else to L4 */
1066 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
1067 /* L1: load halfword from offset 6 (flags and frag offset) */
1068 BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
1069 /* jump to L4 if any bits in frag offset field are set, else to L2 */
1070 BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
1071 /* L2: skip IP header (load index reg with header len) */
1072 BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
1073 /* load udp destination port from halfword[header_len + 2] */
1074 BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
1075 /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
1076 BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
Denys Vlasenkoffc3a932014-02-19 14:17:11 +01001077 /* L3: accept packet ("accept 0x7fffffff bytes") */
1078 /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
1079 BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
1080 /* L4: discard packet ("accept zero bytes") */
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001081 BPF_STMT(BPF_RET|BPF_K, 0),
1082 };
1083 static const struct sock_fprog filter_prog = {
1084 .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
1085 /* casting const away: */
1086 .filter = (struct sock_filter *) filter_instr,
1087 };
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001088 /* Ignoring error (kernel may lack support for this) */
1089 if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
1090 sizeof(filter_prog)) >= 0)
Denys Vlasenko8f2e99c2016-03-30 18:41:23 +02001091 log1("attached filter to raw socket fd"); // log?
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001092 }
Denys Vlasenkoe4785ca2014-02-03 18:03:42 +01001093#endif
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001094
Denys Vlasenkoc52cbea2015-08-24 19:48:03 +02001095 if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
Alexey Froloff3c62bba2012-09-17 16:02:44 +02001096 if (errno != ENOPROTOOPT)
James Byrne69374872019-07-02 11:35:03 +02001097 log1s("can't set PACKET_AUXDATA on raw socket");
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001098 }
1099
James Byrne69374872019-07-02 11:35:03 +02001100 log1s("created raw socket");
Denys Vlasenko6b24d532010-03-22 13:42:13 +01001101
1102 return fd;
1103}
1104
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001105static void change_listen_mode(int new_mode)
Mike Frysinger7031f622006-05-08 03:20:50 +00001106{
Denys Vlasenko8f2e99c2016-03-30 18:41:23 +02001107 log1("entering listen mode: %s",
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001108 new_mode != LISTEN_NONE
1109 ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
1110 : "none"
1111 );
Denis Vlasenko517413f2008-12-10 11:16:47 +00001112
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001113 client_data.listen_mode = new_mode;
1114 if (client_data.sockfd >= 0) {
1115 close(client_data.sockfd);
1116 client_data.sockfd = -1;
Denis Vlasenkofbd29182007-04-07 01:05:47 +00001117 }
Denis Vlasenko517413f2008-12-10 11:16:47 +00001118 if (new_mode == LISTEN_KERNEL)
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001119 client_data.sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_data.interface);
Denis Vlasenko517413f2008-12-10 11:16:47 +00001120 else if (new_mode != LISTEN_NONE)
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001121 client_data.sockfd = udhcp_raw_socket(client_data.ifindex);
1122 /* else LISTEN_NONE: client_data.sockfd stays closed */
Mike Frysinger7031f622006-05-08 03:20:50 +00001123}
1124
Denys Vlasenko9ac55962011-03-12 05:37:54 +01001125/* Called only on SIGUSR1 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001126static void perform_renew(void)
1127{
James Byrne69374872019-07-02 11:35:03 +02001128 bb_simple_info_msg("performing DHCP renew");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001129 switch (client_data.state) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001130 case BOUND:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001131 change_listen_mode(LISTEN_KERNEL);
Mike Frysinger7031f622006-05-08 03:20:50 +00001132 case RENEWING:
1133 case REBINDING:
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001134 client_data.state = RENEW_REQUESTED;
Mike Frysinger7031f622006-05-08 03:20:50 +00001135 break;
1136 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
Rob Landley3f785612006-05-28 01:06:36 +00001137 udhcp_run_script(NULL, "deconfig");
Mike Frysinger7031f622006-05-08 03:20:50 +00001138 case REQUESTING:
1139 case RELEASED:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001140 change_listen_mode(LISTEN_RAW);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001141 client_data.state = INIT_SELECTING;
Mike Frysinger7031f622006-05-08 03:20:50 +00001142 break;
1143 case INIT_SELECTING:
1144 break;
1145 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001146}
1147
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001148static void perform_release(uint32_t server_addr, uint32_t requested_ip)
Mike Frysinger7031f622006-05-08 03:20:50 +00001149{
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001150 char buffer[sizeof("255.255.255.255")];
Mike Frysinger7031f622006-05-08 03:20:50 +00001151 struct in_addr temp_addr;
1152
1153 /* send release packet */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001154 if (client_data.state == BOUND
1155 || client_data.state == RENEWING
1156 || client_data.state == REBINDING
1157 || client_data.state == RENEW_REQUESTED
Denys Vlasenko44399e02016-07-03 20:26:44 +02001158 ) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001159 temp_addr.s_addr = server_addr;
Denis Vlasenko42b3dea2007-07-03 15:47:50 +00001160 strcpy(buffer, inet_ntoa(temp_addr));
Mike Frysinger7031f622006-05-08 03:20:50 +00001161 temp_addr.s_addr = requested_ip;
James Byrne253c4e72019-04-12 17:01:51 +00001162 bb_info_msg("unicasting a release of %s to %s",
Mike Frysinger7031f622006-05-08 03:20:50 +00001163 inet_ntoa(temp_addr), buffer);
1164 send_release(server_addr, requested_ip); /* unicast */
Mike Frysinger7031f622006-05-08 03:20:50 +00001165 }
James Byrne69374872019-07-02 11:35:03 +02001166 bb_simple_info_msg("entering released state");
Peter Korsgaardb6355e22016-08-26 18:46:34 +02001167/*
1168 * We can be here on: SIGUSR2,
1169 * or on exit (SIGTERM) and -R "release on quit" is specified.
1170 * Users requested to be notified in all cases, even if not in one
1171 * of the states above.
1172 */
1173 udhcp_run_script(NULL, "deconfig");
Mike Frysinger7031f622006-05-08 03:20:50 +00001174
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001175 change_listen_mode(LISTEN_NONE);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001176 client_data.state = RELEASED;
Mike Frysinger7031f622006-05-08 03:20:50 +00001177}
1178
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001179static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
1180{
1181 uint8_t *storage;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001182 int len = strnlen(str, 255);
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001183 storage = xzalloc(len + extra + OPT_DATA);
1184 storage[OPT_CODE] = code;
1185 storage[OPT_LEN] = len + extra;
1186 memcpy(storage + extra + OPT_DATA, str, len);
1187 return storage;
1188}
1189
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001190#if BB_MMU
1191static void client_background(void)
1192{
1193 bb_daemonize(0);
1194 logmode &= ~LOGMODE_STDIO;
1195 /* rewrite pidfile, as our pid is different now */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001196 write_pidfile(client_data.pidfile);
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001197}
1198#endif
1199
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001200//usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
1201//usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
1202//usage:#else
1203//usage:# define IF_UDHCP_VERBOSE(...)
1204//usage:#endif
1205//usage:#define udhcpc_trivial_usage
Michel Stam9f412712014-10-30 11:59:04 +01001206//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 +02001207//usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
1208//usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001209//usage:#define udhcpc_full_usage "\n"
Andre Kalb5f2e00f2020-05-05 18:24:25 +02001210//usage: "\n -i IFACE Interface to use (default "CONFIG_UDHCPC_DEFAULT_INTERFACE")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001211//usage: IF_FEATURE_UDHCP_PORT(
1212//usage: "\n -P PORT Use PORT (default 68)"
1213//usage: )
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001214//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001215//usage: "\n -p FILE Create pidfile"
Keith Younge6bb8d32011-03-07 03:18:46 +01001216//usage: "\n -B Request broadcast replies"
Denys Vlasenkoaadb4852013-08-05 02:21:36 +02001217//usage: "\n -t N Send up to N discover packets (default 3)"
Denys Vlasenko456687f2013-08-08 12:33:18 +02001218//usage: "\n -T SEC Pause between packets (default 3)"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001219//usage: "\n -A SEC Wait if lease is not obtained (default 20)"
Denys Vlasenko544143d2019-02-27 08:17:07 +01001220//usage: USE_FOR_MMU(
1221//usage: "\n -b Background if lease is not obtained"
1222//usage: )
Denys Vlasenko456687f2013-08-08 12:33:18 +02001223//usage: "\n -n Exit if lease is not obtained"
1224//usage: "\n -q Exit after obtaining lease"
1225//usage: "\n -R Release IP on exit"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001226//usage: "\n -f Run in foreground"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001227//usage: "\n -S Log to syslog too"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001228//usage: IF_FEATURE_UDHCPC_ARPING(
Michel Stam9f412712014-10-30 11:59:04 +01001229//usage: "\n -a[MSEC] Validate offered address with ARP ping"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001230//usage: )
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001231//usage: "\n -r IP Request this IP address"
Denys Vlasenko9ae6d792013-08-08 12:45:45 +02001232//usage: "\n -o Don't request any options (unless -O is given)"
1233//usage: "\n -O OPT Request option OPT from server (cumulative)"
Denys Vlasenkoc59e06e2010-10-20 16:10:59 +02001234//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
1235//usage: "\n Examples of string, numeric, and hex byte opts:"
1236//usage: "\n -x hostname:bbox - option 12"
1237//usage: "\n -x lease:3600 - option 51 (lease time)"
1238//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001239//usage: "\n -x 14:'\"dumpfile\"' - option 14 (shell-quoted)"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001240//usage: "\n -F NAME Ask server to update DNS mapping for NAME"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001241//usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001242//usage: "\n -C Don't send MAC as client identifier"
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001243//usage: IF_UDHCP_VERBOSE(
1244//usage: "\n -v Verbose"
1245//usage: )
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001246//usage: "\nSignals:"
Denys Vlasenko50089fc2011-11-07 15:44:46 +01001247//usage: "\n USR1 Renew lease"
1248//usage: "\n USR2 Release lease"
Denys Vlasenko8993c3f2010-12-25 06:21:54 +01001249
Denys Vlasenko9e244c72010-10-20 01:38:56 +02001250
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +00001251int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +00001252int udhcpc_main(int argc UNUSED_PARAM, char **argv)
Mike Frysinger7031f622006-05-08 03:20:50 +00001253{
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001254 uint8_t *message;
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001255 const char *str_V, *str_h, *str_F, *str_r;
Michel Stam9f412712014-10-30 11:59:04 +01001256 IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001257 IF_FEATURE_UDHCP_PORT(char *str_P;)
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001258 void *clientid_mac_ptr;
Denis Vlasenko19183682007-12-10 07:03:38 +00001259 llist_t *list_O = NULL;
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001260 llist_t *list_x = NULL;
Denis Vlasenko68af8e72007-11-22 21:41:14 +00001261 int tryagain_timeout = 20;
1262 int discover_timeout = 3;
1263 int discover_retries = 3;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001264 uint32_t server_addr = server_addr; /* for compiler */
1265 uint32_t requested_ip = 0;
Denys Vlasenko860491c2011-11-18 02:09:13 +01001266 uint32_t xid = xid; /* for compiler */
Denis Vlasenkob539c842007-11-29 08:17:45 +00001267 int packet_num;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001268 int timeout; /* must be signed */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001269 int lease_remaining; /* must be signed */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001270 unsigned opt;
Michel Stam9f412712014-10-30 11:59:04 +01001271 IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001272 int retval;
Mike Frysinger7031f622006-05-08 03:20:50 +00001273
Denys Vlasenkodf70a432016-04-21 18:54:36 +02001274 setup_common_bufsiz();
1275
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001276 /* Default options */
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001277 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
1278 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
Andre Kalb5f2e00f2020-05-05 18:24:25 +02001279 client_data.interface = CONFIG_UDHCPC_DEFAULT_INTERFACE;
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001280 client_data.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
1281 client_data.sockfd = -1;
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001282 str_V = "udhcp "BB_VER;
Mike Frysinger7031f622006-05-08 03:20:50 +00001283
Denys Vlasenko65c34c52019-05-31 23:39:22 +02001284 /* Make sure fd 0,1,2 are open */
1285 /* Set up the signal pipe on fds 3,4 - must be before openlog() */
1286 udhcp_sp_setup();
1287
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001288 /* Parse command line */
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001289 opt = getopt32long(argv, "^"
1290 /* O,x: list; -T,-t,-A take numeric param */
1291 "CV:H:h:F:i:np:qRr:s:T:+t:+SA:+O:*ox:*fB"
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001292 USE_FOR_MMU("b")
Michel Stam9f412712014-10-30 11:59:04 +01001293 IF_FEATURE_UDHCPC_ARPING("a::")
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001294 IF_FEATURE_UDHCP_PORT("P:")
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001295 "v"
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001296 "\0" IF_UDHCP_VERBOSE("vv") /* -v is a counter */
Denys Vlasenko036585a2017-08-08 16:38:18 +02001297 , udhcpc_longopts
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001298 , &str_V, &str_h, &str_h, &str_F
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001299 , &client_data.interface, &client_data.pidfile /* i,p */
Denys Vlasenko22542ec2017-08-08 21:55:02 +02001300 , &str_r /* r */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001301 , &client_data.script /* s */
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001302 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
Denis Vlasenko19183682007-12-10 07:03:38 +00001303 , &list_O
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001304 , &list_x
Michel Stam9f412712014-10-30 11:59:04 +01001305 IF_FEATURE_UDHCPC_ARPING(, &str_a)
Denis Vlasenko5e34ff22009-04-21 11:09:40 +00001306 IF_FEATURE_UDHCP_PORT(, &str_P)
Leonid Lisovskiy6c9c0a12011-10-18 00:35:47 +02001307 IF_UDHCP_VERBOSE(, &dhcp_verbose)
Denys Vlasenko7e21f042011-11-08 11:39:41 +01001308 );
Denys Vlasenko2017d482011-11-05 01:24:14 +01001309 if (opt & (OPT_h|OPT_H)) {
1310 //msg added 2011-11
James Byrne69374872019-07-02 11:35:03 +02001311 bb_simple_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001312 client_data.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
Denys Vlasenko2017d482011-11-05 01:24:14 +01001313 }
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001314 if (opt & OPT_F) {
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001315 /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001316 client_data.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001317 /* Flag bits: 0000NEOS
1318 * S: 1 = Client requests server to update A RR in DNS as well as PTR
1319 * O: 1 = Server indicates to client that DNS has been updated regardless
1320 * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
1321 * not "host.domain.com". Format 0 is obsolete.
1322 * N: 1 = Client requests server to not update DNS (S must be 0 then)
1323 * Two [0] bytes which follow are deprecated and must be 0.
1324 */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001325 client_data.fqdn[OPT_DATA + 0] = 0x1;
1326 /*client_data.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
1327 /*client_data.fqdn[OPT_DATA + 2] = 0; */
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001328 }
Denis Vlasenkoe2d3ded2006-11-27 23:43:28 +00001329 if (opt & OPT_r)
1330 requested_ip = inet_addr(str_r);
Denis Vlasenkod55fe3e2008-02-04 13:12:16 +00001331#if ENABLE_FEATURE_UDHCP_PORT
1332 if (opt & OPT_P) {
1333 CLIENT_PORT = xatou16(str_P);
1334 SERVER_PORT = CLIENT_PORT - 1;
1335 }
1336#endif
Michel Stam9f412712014-10-30 11:59:04 +01001337 IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
Denis Vlasenko19183682007-12-10 07:03:38 +00001338 while (list_O) {
Denis Vlasenko18c93022008-08-27 22:29:43 +00001339 char *optstr = llist_pop(&list_O);
Denys Vlasenko5d3aace2011-06-04 05:07:16 +02001340 unsigned n = bb_strtou(optstr, NULL, 0);
1341 if (errno || n > 254) {
Denys Vlasenkoba4fbca2017-06-28 19:18:17 +02001342 n = udhcp_option_idx(optstr, dhcp_option_strings);
Denys Vlasenko5d3aace2011-06-04 05:07:16 +02001343 n = dhcp_optflags[n].code;
1344 }
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001345 client_data.opt_mask[n >> 3] |= 1 << (n & 7);
Denis Vlasenko19183682007-12-10 07:03:38 +00001346 }
Denys Vlasenko293c9452012-07-27 13:25:07 +02001347 if (!(opt & OPT_o)) {
1348 unsigned i, n;
1349 for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
1350 if (dhcp_optflags[i].flags & OPTION_REQ) {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001351 client_data.opt_mask[n >> 3] |= 1 << (n & 7);
Denys Vlasenko293c9452012-07-27 13:25:07 +02001352 }
1353 }
1354 }
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001355 while (list_x) {
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001356 char *optstr = xstrdup(llist_pop(&list_x));
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001357 udhcp_str2optset(optstr, &client_data.options,
Denys Vlasenko60275972018-05-14 11:06:35 +02001358 dhcp_optflags, dhcp_option_strings,
1359 /*dhcpv6:*/ 0
1360 );
Denys Vlasenko266f6f12018-04-13 13:18:34 +02001361 free(optstr);
Denys Vlasenko7e6add12010-03-25 20:32:38 +01001362 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001363
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001364 if (udhcp_read_interface(client_data.interface,
1365 &client_data.ifindex,
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001366 NULL,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001367 client_data.client_mac)
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001368 ) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001369 return 1;
Denys Vlasenko26918dd2009-06-16 12:04:23 +02001370 }
1371
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001372 clientid_mac_ptr = NULL;
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001373 if (!(opt & OPT_C) && !udhcp_find_option(client_data.options, DHCP_CLIENT_ID)) {
Denys Vlasenko1cbdc032010-10-20 01:42:37 +02001374 /* not suppressed and not set, set the default client ID */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001375 client_data.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
1376 client_data.clientid[OPT_DATA] = 1; /* type: ethernet */
1377 clientid_mac_ptr = client_data.clientid + OPT_DATA+1;
1378 memcpy(clientid_mac_ptr, client_data.client_mac, 6);
Denys Vlasenko87fa2162010-03-20 18:06:23 +01001379 }
Denys Vlasenko2017d482011-11-05 01:24:14 +01001380 if (str_V[0] != '\0') {
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001381 // can drop -V, str_V, client_data.vendorclass,
Denys Vlasenko2017d482011-11-05 01:24:14 +01001382 // but need to add "vendor" to the list of recognized
1383 // string opts for this to work;
1384 // and need to tweak add_client_options() too...
1385 // ...so the question is, should we?
1386 //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001387 client_data.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
Denys Vlasenko2017d482011-11-05 01:24:14 +01001388 }
1389
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001390#if !BB_MMU
1391 /* on NOMMU reexec (i.e., background) early */
1392 if (!(opt & OPT_f)) {
1393 bb_daemonize_or_rexec(0 /* flags */, argv);
Denis Vlasenkoa19e6492009-03-11 14:40:00 +00001394 logmode = LOGMODE_NONE;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001395 }
1396#endif
1397 if (opt & OPT_S) {
Denis Vlasenko5e4fda02009-03-08 23:46:48 +00001398 openlog(applet_name, LOG_PID, LOG_DAEMON);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001399 logmode |= LOGMODE_SYSLOG;
1400 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001401
Denis Vlasenko80edead2007-08-02 22:31:05 +00001402 /* Create pidfile */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001403 write_pidfile(client_data.pidfile);
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001404 /* Goes to stdout (unless NOMMU) and possibly syslog */
James Byrne69374872019-07-02 11:35:03 +02001405 bb_simple_info_msg("started, v"BB_VER);
Denys Vlasenko8d114452010-03-22 13:44:09 +01001406 /* We want random_xid to be random... */
1407 srand(monotonic_us());
Mike Frysinger7031f622006-05-08 03:20:50 +00001408
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001409 client_data.state = INIT_SELECTING;
Rob Landley3f785612006-05-28 01:06:36 +00001410 udhcp_run_script(NULL, "deconfig");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001411 change_listen_mode(LISTEN_RAW);
Denis Vlasenkob539c842007-11-29 08:17:45 +00001412 packet_num = 0;
Denis Vlasenkofc9e1082008-05-26 17:32:35 +00001413 timeout = 0;
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001414 lease_remaining = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001415
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001416 /* Main event loop. select() waits on signal pipe and possibly
1417 * on sockfd.
1418 * "continue" statements in code below jump to the top of the loop.
1419 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001420 for (;;) {
Denys Vlasenko52a515d2017-02-16 23:25:44 +01001421 struct pollfd pfds[2];
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001422 struct dhcp_packet packet;
Mike Frysinger7031f622006-05-08 03:20:50 +00001423
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001424 //bb_error_msg("sockfd:%d, listen_mode:%d", client_data.sockfd, client_data.listen_mode);
Denis Vlasenko517413f2008-12-10 11:16:47 +00001425
1426 /* Was opening raw or udp socket here
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001427 * if (client_data.listen_mode != LISTEN_NONE && client_data.sockfd < 0),
Denis Vlasenko517413f2008-12-10 11:16:47 +00001428 * but on fast network renew responses return faster
1429 * than we open sockets. Thus this code is moved
1430 * to change_listen_mode(). Thus we open listen socket
1431 * BEFORE we send renew request (see "case BOUND:"). */
1432
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001433 udhcp_sp_fd_set(pfds, client_data.sockfd);
Mike Frysinger7031f622006-05-08 03:20:50 +00001434
Denys Vlasenko8d114452010-03-22 13:44:09 +01001435 retval = 0;
1436 /* If we already timed out, fall through with retval = 0, else... */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001437 if (timeout > 0) {
1438 unsigned diff;
1439
1440 if (timeout > INT_MAX/1000)
1441 timeout = INT_MAX/1000;
1442 log1("waiting %u seconds", timeout);
1443 diff = (unsigned)monotonic_sec();
1444 retval = poll(pfds, 2, timeout * 1000);
Denis Vlasenkob2342912008-05-21 07:02:16 +00001445 if (retval < 0) {
1446 /* EINTR? A signal was caught, don't panic */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001447 if (errno == EINTR) {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001448 diff = (unsigned)monotonic_sec() - diff;
1449 lease_remaining -= diff;
1450 if (lease_remaining < 0)
1451 lease_remaining = 0;
1452 timeout -= diff;
Denis Vlasenkob2342912008-05-21 07:02:16 +00001453 continue;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001454 }
Denys Vlasenko10ad6222017-04-17 16:13:32 +02001455 /* Else: an error occurred, panic! */
James Byrne69374872019-07-02 11:35:03 +02001456 bb_simple_perror_msg_and_die("poll");
Denis Vlasenko80edead2007-08-02 22:31:05 +00001457 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001458 }
1459
1460 /* If timeout dropped to zero, time to become active:
1461 * resend discover/renew/whatever
1462 */
1463 if (retval == 0) {
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001464 /* When running on a bridge, the ifindex may have changed
1465 * (e.g. if member interfaces were added/removed
1466 * or if the status of the bridge changed).
1467 * Refresh ifindex and client_mac:
1468 */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001469 if (udhcp_read_interface(client_data.interface,
1470 &client_data.ifindex,
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001471 NULL,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001472 client_data.client_mac)
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001473 ) {
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001474 goto ret0; /* iface is gone? */
Denys Vlasenko5d374e92010-10-20 22:26:38 +02001475 }
1476 if (clientid_mac_ptr)
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001477 memcpy(clientid_mac_ptr, client_data.client_mac, 6);
Denys Vlasenkoa5048fa2010-10-20 21:38:29 +02001478
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001479 switch (client_data.state) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001480 case INIT_SELECTING:
Felix Fietkau1c7a58d2012-09-27 16:22:24 +02001481 if (!discover_retries || packet_num < discover_retries) {
Mike Frysinger7031f622006-05-08 03:20:50 +00001482 if (packet_num == 0)
1483 xid = random_xid();
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001484 /* broadcast */
1485 send_discover(xid, requested_ip);
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001486 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001487 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001488 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001489 }
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001490 leasefail:
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001491 udhcp_run_script(NULL, "leasefail");
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001492#if BB_MMU /* -b is not supported on NOMMU */
1493 if (opt & OPT_b) { /* background if no lease */
James Byrne69374872019-07-02 11:35:03 +02001494 bb_simple_info_msg("no lease, forking to background");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001495 client_background();
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001496 /* do not background again! */
Andrey Mazo87e21622019-02-22 16:46:19 -05001497 opt = ((opt & ~(OPT_b|OPT_n)) | OPT_f);
1498 /* ^^^ also disables -n (-b takes priority over -n):
1499 * ifup's default udhcpc options are -R -n,
1500 * and users want to be able to add -b
1501 * (in a config file) to make it background
1502 * _and not exit_.
1503 */
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001504 } else
1505#endif
1506 if (opt & OPT_n) { /* abort if no lease */
James Byrne69374872019-07-02 11:35:03 +02001507 bb_simple_info_msg("no lease, failing");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001508 retval = 1;
1509 goto ret;
1510 }
Denis Vlasenko6de89942008-05-21 07:05:06 +00001511 /* wait before trying again */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001512 timeout = tryagain_timeout;
1513 packet_num = 0;
1514 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001515 case REQUESTING:
Denys Vlasenko86d9f602016-03-04 17:00:56 +01001516 if (packet_num < 3) {
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001517 /* send broadcast select packet */
1518 send_select(xid, server_addr, requested_ip);
Denis Vlasenko6de89942008-05-21 07:05:06 +00001519 timeout = discover_timeout;
Mike Frysinger7031f622006-05-08 03:20:50 +00001520 packet_num++;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001521 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001522 }
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001523 /* Timed out, go back to init state.
1524 * "discover...select...discover..." loops
Denis Vlasenko7d9399e2008-09-26 22:21:03 +00001525 * were seen in the wild. Treat them similarly
Denis Vlasenkocdb0b652008-09-26 09:34:15 +00001526 * to "no response to discover" case */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001527 change_listen_mode(LISTEN_RAW);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001528 client_data.state = INIT_SELECTING;
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001529 goto leasefail;
Mike Frysinger7031f622006-05-08 03:20:50 +00001530 case BOUND:
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001531 /* 1/2 lease passed, enter renewing state */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001532 client_data.state = RENEWING;
1533 client_data.first_secs = 0; /* make secs field count from 0 */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001534 change_listen_mode(LISTEN_KERNEL);
James Byrne69374872019-07-02 11:35:03 +02001535 log1s("entering renew state");
Mike Frysinger7031f622006-05-08 03:20:50 +00001536 /* fall right through */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001537 case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
1538 case_RENEW_REQUESTED:
Mike Frysinger7031f622006-05-08 03:20:50 +00001539 case RENEWING:
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001540 if (packet_num < 3) {
1541 packet_num++;
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001542 /* send an unicast renew request */
1543 /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
1544 * a new UDP socket for sending inside send_renew.
1545 * I hazard to guess existing listening socket
1546 * is somehow conflicting with it, but why is it
1547 * not deterministic then?! Strange.
Denys Vlasenko753a3ce2009-07-19 04:27:10 +02001548 * Anyway, it does recover by eventually failing through
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001549 * into INIT_SELECTING state.
1550 */
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +02001551 if (send_renew(xid, server_addr, requested_ip) >= 0) {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001552 timeout = discover_timeout;
1553 /* ^^^ used to be = lease_remaining / 2 - WAY too long */
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +02001554 continue;
1555 }
1556 /* else: error sending.
1557 * example: ENETUNREACH seen with server
1558 * which gave us bogus server ID 1.1.1.1
1559 * which wasn't reachable (and probably did not exist).
1560 */
Mike Frysinger7031f622006-05-08 03:20:50 +00001561 }
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001562//TODO: if 3 renew's failed (no reply) but remaining lease is large,
1563//it might make sense to make a large pause (~1 hour?) and try later?
Denys Vlasenkoa6a3ad32017-09-29 15:55:24 +02001564 /* Timed out or error, enter rebinding state */
James Byrne69374872019-07-02 11:35:03 +02001565 log1s("entering rebinding state");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001566 client_data.state = REBINDING;
Denis Vlasenko6de89942008-05-21 07:05:06 +00001567 /* fall right through */
Mike Frysinger7031f622006-05-08 03:20:50 +00001568 case REBINDING:
Denys Vlasenko219757f2009-10-08 23:05:46 +02001569 /* Switch to bcast receive */
1570 change_listen_mode(LISTEN_RAW);
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001571 /* Lease is *really* about to run out,
1572 * try to find DHCP server using broadcast */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001573 if (lease_remaining > 0) {
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001574 /* send a broadcast renew request */
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001575 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001576 timeout = discover_timeout;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001577 continue;
Mike Frysinger7031f622006-05-08 03:20:50 +00001578 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001579 /* Timed out, enter init state */
James Byrne69374872019-07-02 11:35:03 +02001580 bb_simple_info_msg("lease lost, entering init state");
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001581 udhcp_run_script(NULL, "deconfig");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001582 client_data.state = INIT_SELECTING;
1583 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001584 timeout = 0;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001585 packet_num = 0;
1586 continue;
1587 /* case RELEASED: */
Mike Frysinger7031f622006-05-08 03:20:50 +00001588 }
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001589 /* yah, I know, *you* say it would never happen */
1590 timeout = INT_MAX;
1591 continue; /* back to main loop */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001592 } /* if poll timed out */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001593
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001594 /* poll() didn't timeout, something happened */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001595
1596 /* Is it a signal? */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001597 switch (udhcp_sp_read()) {
Denys Vlasenko4248c332009-06-26 23:23:16 +02001598 case SIGUSR1:
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001599 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001600 perform_renew();
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001601 if (client_data.state == RENEW_REQUESTED)
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001602 goto case_RENEW_REQUESTED;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001603 /* Start things over */
1604 packet_num = 0;
Denys Vlasenko7d6a7912009-07-19 04:24:23 +02001605 /* Kill any timeouts, user wants this to hurry along */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001606 timeout = 0;
1607 continue;
1608 case SIGUSR2:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001609 perform_release(server_addr, requested_ip);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001610 timeout = INT_MAX;
1611 continue;
1612 case SIGTERM:
James Byrne253c4e72019-04-12 17:01:51 +00001613 bb_info_msg("received %s", "SIGTERM");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001614 goto ret0;
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001615 }
1616
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001617 /* Is it a packet? */
Denys Vlasenko3293bc12018-03-10 19:01:48 +01001618 if (!pfds[1].revents)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001619 continue; /* no */
Mike Frysinger7031f622006-05-08 03:20:50 +00001620
Denys Vlasenko4248c332009-06-26 23:23:16 +02001621 {
1622 int len;
1623
1624 /* A packet is ready, read it */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001625 if (client_data.listen_mode == LISTEN_KERNEL)
1626 len = udhcp_recv_kernel_packet(&packet, client_data.sockfd);
Denis Vlasenkob76b9a42008-01-25 22:46:34 +00001627 else
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001628 len = udhcp_recv_raw_packet(&packet, client_data.sockfd);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001629 if (len == -1) {
1630 /* Error is severe, reopen socket */
Denys Vlasenko6f97b302017-09-29 18:17:25 +02001631 bb_error_msg("read error: "STRERROR_FMT", reopening socket" STRERROR_ERRNO);
Denis Vlasenko6de89942008-05-21 07:05:06 +00001632 sleep(discover_timeout); /* 3 seconds by default */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001633 change_listen_mode(client_data.listen_mode); /* just close and reopen */
Denis Vlasenko6de89942008-05-21 07:05:06 +00001634 }
Denis Vlasenko6de89942008-05-21 07:05:06 +00001635 if (len < 0)
1636 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001637 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001638
Denys Vlasenko4248c332009-06-26 23:23:16 +02001639 if (packet.xid != xid) {
Denys Vlasenkoa4959ee2021-02-21 16:32:07 +01001640 log1("xid %x (our is %x)%s",
1641 (unsigned)packet.xid, (unsigned)xid,
1642 ", ignoring packet"
1643 );
Denys Vlasenko4248c332009-06-26 23:23:16 +02001644 continue;
1645 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001646
Denys Vlasenko4248c332009-06-26 23:23:16 +02001647 /* Ignore packets that aren't for us */
1648 if (packet.hlen != 6
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001649 || memcmp(packet.chaddr, client_data.client_mac, 6) != 0
Denys Vlasenko4248c332009-06-26 23:23:16 +02001650 ) {
Denys Vlasenkoac906fa2009-06-17 11:54:52 +02001651//FIXME: need to also check that last 10 bytes are zero
James Byrne69374872019-07-02 11:35:03 +02001652 log1("chaddr does not match%s", ", ignoring packet"); // log2?
Denys Vlasenko4248c332009-06-26 23:23:16 +02001653 continue;
1654 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001655
Denys Vlasenkodde8bdc2010-03-22 14:29:13 +01001656 message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001657 if (message == NULL) {
James Byrne69374872019-07-02 11:35:03 +02001658 bb_info_msg("no message type option%s", ", ignoring packet");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001659 continue;
1660 }
Mike Frysinger7031f622006-05-08 03:20:50 +00001661
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001662 switch (client_data.state) {
Denys Vlasenko4248c332009-06-26 23:23:16 +02001663 case INIT_SELECTING:
Denys Vlasenko860491c2011-11-18 02:09:13 +01001664 /* Must be a DHCPOFFER */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001665 if (*message == DHCPOFFER) {
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001666 uint8_t *temp;
1667
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001668/* What exactly is server's IP? There are several values.
1669 * Example DHCP offer captured with tchdump:
1670 *
1671 * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
1672 * BOOTP fields:
1673 * Your-IP 10.34.25.202
1674 * Server-IP 10.34.32.125 // "next server" IP
1675 * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
1676 * DHCP options:
1677 * DHCP-Message Option 53, length 1: Offer
1678 * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
1679 * Default-Gateway Option 3, length 4: 10.34.25.254 // router
1680 *
1681 * We think that real server IP (one to use in renew/release)
1682 * is one in Server-ID option. But I am not 100% sure.
Denys Vlasenkoee320c62011-10-23 18:05:58 +02001683 * IP header's src and Gateway-IP (same in this example)
Denys Vlasenko2af2acf2011-10-20 14:47:41 +02001684 * might work too.
1685 * "Next server" and router are definitely wrong ones to use, though...
1686 */
James Byrne253c4e72019-04-12 17:01:51 +00001687/* We used to ignore packets without DHCP_SERVER_ID.
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001688 * I've got user reports from people who run "address-less" servers.
1689 * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
1690 * They say ISC DHCP client supports this case.
1691 */
1692 server_addr = 0;
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001693 temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001694 if (!temp) {
James Byrne69374872019-07-02 11:35:03 +02001695 bb_simple_info_msg("no server ID, using 0.0.0.0");
Denys Vlasenko8d3efaf2013-11-03 19:20:54 +01001696 } else {
1697 /* it IS unaligned sometimes, don't "optimize" */
1698 move_from_unaligned32(server_addr, temp);
Mike Frysinger7031f622006-05-08 03:20:50 +00001699 }
Denys Vlasenkob3af65b2010-10-20 21:37:23 +02001700 /*xid = packet.xid; - already is */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001701 requested_ip = packet.yiaddr;
1702
1703 /* enter requesting state */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001704 client_data.state = REQUESTING;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001705 timeout = 0;
1706 packet_num = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001707 }
1708 continue;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001709 case REQUESTING:
1710 case RENEWING:
Denys Vlasenko13ca4b12009-07-19 04:07:21 +02001711 case RENEW_REQUESTED:
Denys Vlasenko4248c332009-06-26 23:23:16 +02001712 case REBINDING:
1713 if (*message == DHCPACK) {
Denys Vlasenko28634922014-12-21 16:10:22 +01001714 unsigned start;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001715 struct in_addr temp_addr;
Denys Vlasenko64483322021-02-20 18:09:54 +01001716 char server_str[sizeof("255.255.255.255")];
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001717 uint8_t *temp;
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001718
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001719 temp_addr.s_addr = server_addr;
1720 strcpy(server_str, inet_ntoa(temp_addr));
1721 temp_addr.s_addr = packet.yiaddr;
1722
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001723 temp = udhcp_get_option32(&packet, DHCP_LEASE_TIME);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001724 if (!temp) {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001725 lease_remaining = 60 * 60;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001726 } else {
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001727 uint32_t lease;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001728 /* it IS unaligned sometimes, don't "optimize" */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001729 move_from_unaligned32(lease, temp);
1730 lease_remaining = ntohl(lease);
Denys Vlasenko4248c332009-06-26 23:23:16 +02001731 }
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001732 /* Log message _before_ we sanitize lease */
1733 bb_info_msg("lease of %s obtained from %s, lease time %u%s",
1734 inet_ntoa(temp_addr), server_str, (unsigned)lease_remaining,
1735 temp ? "" : " (default)"
1736 );
1737 /* paranoia: must not be too small and not prone to overflows */
1738 /* NB: 60s leases _are_ used in real world
1739 * (temporary IPs while ISP modem initializes)
1740 * do not break this case by bumplit it up.
1741 */
1742 if (lease_remaining < 0) /* signed overflow? */
1743 lease_remaining = INT_MAX;
1744 if (lease_remaining < 30)
1745 lease_remaining = 30;
1746 requested_ip = packet.yiaddr;
Denis Vlasenko223bc972007-11-22 00:58:49 +00001747#if ENABLE_FEATURE_UDHCPC_ARPING
Denys Vlasenko4248c332009-06-26 23:23:16 +02001748 if (opt & OPT_a) {
Denis Vlasenko739e30f2008-09-26 23:45:20 +00001749/* RFC 2131 3.1 paragraph 5:
1750 * "The client receives the DHCPACK message with configuration
1751 * parameters. The client SHOULD perform a final check on the
1752 * parameters (e.g., ARP for allocated network address), and notes
1753 * the duration of the lease specified in the DHCPACK message. At this
1754 * point, the client is configured. If the client detects that the
1755 * address is already in use (e.g., through the use of ARP),
1756 * the client MUST send a DHCPDECLINE message to the server and restarts
1757 * the configuration process..." */
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001758 if (!arpping(requested_ip,
Denys Vlasenko4248c332009-06-26 23:23:16 +02001759 NULL,
1760 (uint32_t) 0,
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001761 client_data.client_mac,
1762 client_data.interface,
Michel Stam9f412712014-10-30 11:59:04 +01001763 arpping_ms)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001764 ) {
James Byrne69374872019-07-02 11:35:03 +02001765 bb_simple_info_msg("offered address is in use "
Denys Vlasenko4248c332009-06-26 23:23:16 +02001766 "(got ARP reply), declining");
Denys Vlasenko860491c2011-11-18 02:09:13 +01001767 send_decline(/*xid,*/ server_addr, packet.yiaddr);
Denis Vlasenko223bc972007-11-22 00:58:49 +00001768
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001769 if (client_data.state != REQUESTING)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001770 udhcp_run_script(NULL, "deconfig");
1771 change_listen_mode(LISTEN_RAW);
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001772 client_data.state = INIT_SELECTING;
1773 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001774 requested_ip = 0;
1775 timeout = tryagain_timeout;
1776 packet_num = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001777 continue; /* back to main loop */
Denis Vlasenko223bc972007-11-22 00:58:49 +00001778 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001779 }
Denis Vlasenko223bc972007-11-22 00:58:49 +00001780#endif
Denys Vlasenko28634922014-12-21 16:10:22 +01001781
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001782 /* enter bound state */
Denys Vlasenko28634922014-12-21 16:10:22 +01001783 start = monotonic_sec();
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001784 udhcp_run_script(&packet, client_data.state == REQUESTING ? "bound" : "renew");
Denys Vlasenkoa1a77ad2021-05-01 11:54:08 +02001785 timeout = (unsigned)lease_remaining / 2;
1786//TODO: why / 2?
1787 timeout -= (unsigned)monotonic_sec() - start;
1788 packet_num = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001789
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001790 client_data.state = BOUND;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001791 change_listen_mode(LISTEN_NONE);
1792 if (opt & OPT_q) { /* quit after lease */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001793 goto ret0;
1794 }
Justin Maggardaa369e02009-08-13 01:26:17 +02001795 /* future renew failures should not exit (JM) */
1796 opt &= ~OPT_n;
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001797#if BB_MMU /* NOMMU case backgrounded earlier */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001798 if (!(opt & OPT_f)) {
1799 client_background();
1800 /* do not background again! */
1801 opt = ((opt & ~OPT_b) | OPT_f);
1802 }
Denis Vlasenko21765fa2008-06-13 20:44:05 +00001803#endif
Denys Vlasenko860491c2011-11-18 02:09:13 +01001804 /* make future renew packets use different xid */
1805 /* xid = random_xid(); ...but why bother? */
Denys Vlasenko28634922014-12-21 16:10:22 +01001806
Denys Vlasenko4248c332009-06-26 23:23:16 +02001807 continue; /* back to main loop */
Mike Frysinger7031f622006-05-08 03:20:50 +00001808 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001809 if (*message == DHCPNAK) {
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001810 /* If network has more than one DHCP server,
1811 * "wrong" server can reply first, with a NAK.
1812 * Do not interpret it as a NAK from "our" server.
1813 */
1814 if (server_addr != 0) {
1815 uint32_t svid;
1816 uint8_t *temp;
1817
Denys Vlasenko6d3b4bb2018-12-17 18:07:18 +01001818 temp = udhcp_get_option32(&packet, DHCP_SERVER_ID);
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001819 if (!temp) {
1820 non_matching_svid:
Peter Korsgaardb6355e22016-08-26 18:46:34 +02001821 log1("received DHCP NAK with wrong"
James Byrne69374872019-07-02 11:35:03 +02001822 " server ID%s", ", ignoring packet");
Denys Vlasenkoe2318bb2014-02-27 18:15:50 +01001823 continue;
1824 }
1825 move_from_unaligned32(svid, temp);
1826 if (svid != server_addr)
1827 goto non_matching_svid;
1828 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001829 /* return to init state */
James Byrne253c4e72019-04-12 17:01:51 +00001830 bb_info_msg("received %s", "DHCP NAK");
Denys Vlasenko4248c332009-06-26 23:23:16 +02001831 udhcp_run_script(&packet, "nak");
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001832 if (client_data.state != REQUESTING)
Denys Vlasenko4248c332009-06-26 23:23:16 +02001833 udhcp_run_script(NULL, "deconfig");
1834 change_listen_mode(LISTEN_RAW);
1835 sleep(3); /* avoid excessive network traffic */
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001836 client_data.state = INIT_SELECTING;
1837 client_data.first_secs = 0; /* make secs field count from 0 */
Denys Vlasenko4248c332009-06-26 23:23:16 +02001838 requested_ip = 0;
Denis Vlasenkob539c842007-11-29 08:17:45 +00001839 timeout = 0;
Denys Vlasenko4248c332009-06-26 23:23:16 +02001840 packet_num = 0;
Mike Frysinger7031f622006-05-08 03:20:50 +00001841 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001842 continue;
1843 /* case BOUND: - ignore all packets */
1844 /* case RELEASED: - ignore all packets */
Mike Frysinger7031f622006-05-08 03:20:50 +00001845 }
Denys Vlasenko4248c332009-06-26 23:23:16 +02001846 /* back to main loop */
Denis Vlasenko9cdfd142007-11-22 01:00:00 +00001847 } /* for (;;) - main loop ends */
1848
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001849 ret0:
Denys Vlasenko0fd43472011-11-07 00:54:27 +01001850 if (opt & OPT_R) /* release on quit */
1851 perform_release(server_addr, requested_ip);
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001852 retval = 0;
1853 ret:
Denys Vlasenkobcb1fc32019-05-26 15:01:13 +02001854 /*if (client_data.pidfile) - remove_pidfile has its own check */
1855 remove_pidfile(client_data.pidfile);
Denis Vlasenko6e6d3312007-05-03 23:39:35 +00001856 return retval;
Mike Frysinger7031f622006-05-08 03:20:50 +00001857}