summaryrefslogtreecommitdiff
path: root/networking/udhcp/common.h
blob: 60255eefaa503daf43f2d3728b252b7502143de3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
/* vi: set sw=4 ts=4: */
/*
 * Russ Dill <Russ.Dill@asu.edu> September 2001
 * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#ifndef UDHCP_COMMON_H
#define UDHCP_COMMON_H 1

#include "libbb.h"
#include "common_bufsiz.h"
#include <netinet/udp.h>
#include <netinet/ip.h>

PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN

extern const uint8_t MAC_BCAST_ADDR[6] ALIGN2; /* six all-ones */


/*** DHCP packet ***/

/* DHCP protocol. See RFC 2131 */
#define DHCP_MAGIC              0x63825363
#define DHCP_OPTIONS_BUFSIZE    308
#define BOOTREQUEST             1
#define BOOTREPLY               2

//TODO: rename ciaddr/yiaddr/chaddr
struct dhcp_packet {
	uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
	uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
	uint8_t hlen;    /* hardware address length */
	uint8_t hops;    /* used by relay agents only */
	uint32_t xid;    /* unique id */
	uint16_t secs;   /* elapsed since client began acquisition/renewal */
	uint16_t flags;  /* only one flag so far: */
#define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
	uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
	uint32_t yiaddr; /* 'your' (client) IP address */
	/* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
	uint32_t siaddr_nip;
	uint32_t gateway_nip; /* aka 'giaddr': relay agent IP address */
	uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
	uint8_t sname[64];    /* server host name (ASCIZ) */
	uint8_t file[128];    /* boot file name (ASCIZ) */
	uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
	uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
} PACKED;
#define DHCP_PKT_SNAME_LEN      64
#define DHCP_PKT_FILE_LEN      128
#define DHCP_PKT_SNAME_LEN_STR "64"
#define DHCP_PKT_FILE_LEN_STR "128"

struct ip_udp_dhcp_packet {
	struct iphdr ip;
	struct udphdr udp;
	struct dhcp_packet data;
} PACKED;

struct udp_dhcp_packet {
	struct udphdr udp;
	struct dhcp_packet data;
} PACKED;

enum {
	IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
	UDP_DHCP_SIZE    = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
	DHCP_SIZE        = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
};

/* Let's see whether compiler understood us right */
struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
	char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
};


/*** Options ***/

enum {
	OPTION_IP = 1,
	OPTION_IP_PAIR,
	OPTION_STRING,
	/* Opts of STRING_HOST type will be sanitized before they are passed
	 * to udhcpc script's environment: */
	OPTION_STRING_HOST,
//	OPTION_BOOLEAN,
	OPTION_U8,
	OPTION_U16,
//	OPTION_S16,
	OPTION_U32,
	OPTION_S32,
	OPTION_BIN,
	OPTION_STATIC_ROUTES,
	OPTION_6RD,
#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
	OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
#endif
#if ENABLE_FEATURE_UDHCP_RFC3397
	OPTION_SIP_SERVERS,
#endif

	OPTION_TYPE_MASK = 0x0f,
	/* Client requests this option by default */
	OPTION_REQ  = 0x10,
	/* There can be a list of 1 or more of these */
	OPTION_LIST = 0x20,
};

/* DHCP option codes (partial list). See RFC 2132 and
 * http://www.iana.org/assignments/bootp-dhcp-parameters/
 * Commented out options are handled by common option machinery,
 * uncommented ones have special cases (grep for them to see).
 */
#define DHCP_PADDING            0x00
#define DHCP_SUBNET             0x01
//#define DHCP_TIME_OFFSET      0x02 /* (localtime - UTC_time) in seconds. signed */
//#define DHCP_ROUTER           0x03
//#define DHCP_TIME_SERVER      0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
//#define DHCP_NAME_SERVER      0x05 /* IEN 116 _really_ ancient kind of NS */
//#define DHCP_DNS_SERVER       0x06
//#define DHCP_LOG_SERVER       0x07 /* port 704 UDP log (not syslog) */
//#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
//#define DHCP_LPR_SERVER       0x09
#define DHCP_HOST_NAME          0x0c /* 12: either client informs server or server gives name to client */
//#define DHCP_BOOT_SIZE        0x0d
//#define DHCP_DOMAIN_NAME      0x0f /* 15: server gives domain suffix */
//#define DHCP_SWAP_SERVER      0x10
//#define DHCP_ROOT_PATH        0x11
//#define DHCP_IP_TTL           0x17
//#define DHCP_MTU              0x1a
//#define DHCP_BROADCAST        0x1c
//#define DHCP_ROUTES           0x21
//#define DHCP_NIS_DOMAIN       0x28
//#define DHCP_NIS_SERVER       0x29
//#define DHCP_NTP_SERVER       0x2a
//#define DHCP_WINS_SERVER      0x2c
#define DHCP_REQUESTED_IP       0x32 /* 50: sent by client if specific IP is wanted */
#define DHCP_LEASE_TIME         0x33 /* 51: */
#define DHCP_OPTION_OVERLOAD    0x34 /* 52: */
#define DHCP_MESSAGE_TYPE       0x35 /* 53: */
#define DHCP_SERVER_ID          0x36 /* 54: server's IP */
#define DHCP_PARAM_REQ          0x37 /* 55: list of options client wants */
//#define DHCP_ERR_MESSAGE      0x38 /* 56: error message when sending NAK etc */
#define DHCP_MAX_SIZE           0x39 /* 57: */
#define DHCP_VENDOR             0x3c /* 60: client's vendor (a string) */
#define DHCP_CLIENT_ID          0x3d /* 61: by default client's MAC addr, but may be arbitrarily long */
//#define DHCP_TFTP_SERVER_NAME 0x42 /* 66: same as 'sname' field */
//#define DHCP_BOOT_FILE        0x43 /* 67: same as 'file' field */
//#define DHCP_USER_CLASS       0x4d /* 77: RFC 3004. set of LASCII strings. "I am a printer" etc */
#define DHCP_FQDN               0x51 /* 81: client asks to update DNS to map its FQDN to its new IP */
//#define DHCP_PCODE            0x64 /* 100: RFC 4833. IEEE 1003.1 TZ string */
//#define DHCP_TCODE            0x65 /* 101: RFC 4833. Reference to the TZ database string */
//#define DHCP_DOMAIN_SEARCH    0x77 /* 119: RFC 3397. set of ASCIZ string, DNS-style compressed */
//#define DHCP_SIP_SERVERS      0x78 /* 120: RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
//#define DHCP_STATIC_ROUTES    0x79 /* 121: RFC 3442. (mask,ip,router) tuples */
//#define DHCP_VLAN_ID          0x84 /* 132: 802.1P VLAN ID */
//#define DHCP_VLAN_PRIORITY    0x85 /* 133: 802.1Q VLAN priority */
//#define DHCP_PXE_CONF_FILE    0xd1 /* 209: RFC 5071 Configuration file */
//#define DHCP_PXE_PATH_PREFIX  0xd2 /* 210: RFC 5071 Path prefix */
//#define DHCP_REBOOT_TIME      0xd3 /* 211: RFC 5071 Reboot time */
//#define DHCP_MS_STATIC_ROUTES 0xf9 /* 249: Microsoft's pre-RFC 3442 code for 0x79? */
//#define DHCP_WPAD             0xfc /* 252: MSIE's Web Proxy Autodiscovery Protocol */
#define DHCP_END                0xff /* 255: */

/* Offsets in option byte sequence */
#define OPT_CODE                0
#define OPT_LEN                 1
#define OPT_DATA                2
/* Offsets in option byte sequence for DHCPv6 */
#define D6_OPT_CODE             0
#define D6_OPT_LEN              2
#define D6_OPT_DATA             4
/* Bits in "overload" option */
#define OPTION_FIELD            0
#define FILE_FIELD              1
#define SNAME_FIELD             2

/* DHCP_MESSAGE_TYPE values */
#define DHCPDISCOVER            1 /* client -> server */
#define DHCPOFFER               2 /* client <- server */
#define DHCPREQUEST             3 /* client -> server */
#define DHCPDECLINE             4 /* client -> server */
#define DHCPACK                 5 /* client <- server */
#define DHCPNAK                 6 /* client <- server */
#define DHCPRELEASE             7 /* client -> server */
#define DHCPINFORM              8 /* client -> server */
#define DHCP_MINTYPE DHCPDISCOVER
#define DHCP_MAXTYPE DHCPINFORM

struct dhcp_optflag {
	uint8_t flags;
	uint8_t code;
};

struct option_set {
	uint8_t *data;
	struct option_set *next;
};

#if ENABLE_UDHCPC || ENABLE_UDHCPD
extern const struct dhcp_optflag dhcp_optflags[];
extern const char dhcp_option_strings[] ALIGN1;
#endif
extern const uint8_t dhcp_option_lengths[] ALIGN1;

unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings);

uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
/* Same as above + ensures that option length is 4 bytes
 * (returns NULL if size is different)
 */
uint8_t *udhcp_get_option32(struct dhcp_packet *packet, int code) FAST_FUNC;
int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
#if ENABLE_UDHCPC || ENABLE_UDHCPD
void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
#endif
#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
#endif
struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;

// RFC 2131  Table 5: Fields and options used by DHCP clients
//
// Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero, 'chaddr' is always client's MAC
//
// Field      DHCPDISCOVER          DHCPINFORM            DHCPREQUEST           DHCPDECLINE         DHCPRELEASE
// -----      ------------          ------------          -----------           -----------         -----------
// 'xid'      selected by client    selected by client    'xid' from server     selected by client  selected by client
//                                                        DHCPOFFER message
// 'secs'     0 or seconds since    0 or seconds since    0 or seconds since    0                   0
//            DHCP process started  DHCP process started  DHCP process started
// 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       Set 'BROADCAST'       0                   0
//            flag if client needs  flag if client needs  flag if client needs
//            broadcast reply       broadcast reply       broadcast reply
// 'ciaddr'   0                     client's IP           0 or client's IP      0                   client's IP
//                                                        (BOUND/RENEW/REBIND)
// 'sname'    options or sname      options or sname      options or sname      (unused)            (unused)
// 'file'     options or file       options or file       options or file       (unused)            (unused)
// 'options'  options               options               options               message type opt    message type opt
//
// Option                     DHCPDISCOVER  DHCPINFORM  DHCPREQUEST             DHCPDECLINE  DHCPRELEASE
// ------                     ------------  ----------  -----------             -----------  -----------
// Requested IP address       MAY           MUST NOT    MUST (in SELECTING      MUST         MUST NOT
//                                                      or INIT-REBOOT)
//                                                      MUST NOT (in BOUND
//                                                      or RENEWING)
// IP address lease time      MAY           MUST NOT    MAY                     MUST NOT     MUST NOT
// Use 'file'/'sname' fields  MAY           MAY         MAY                     MAY          MAY
// Client identifier          MAY           MAY         MAY                     MAY          MAY
// Vendor class identifier    MAY           MAY         MAY                     MUST NOT     MUST NOT
// Server identifier          MUST NOT      MUST NOT    MUST (after SELECTING)  MUST         MUST
//                                                      MUST NOT (after
//                                                      INIT-REBOOT, BOUND,
//                                                      RENEWING or REBINDING)
// Parameter request list     MAY           MAY         MAY                     MUST NOT     MUST NOT
// Maximum message size       MAY           MAY         MAY                     MUST NOT     MUST NOT
// Message                    SHOULD NOT    SHOULD NOT  SHOULD NOT              SHOULD       SHOULD
// Site-specific              MAY           MAY         MAY                     MUST NOT     MUST NOT
// All others                 MAY           MAY         MAY                     MUST NOT     MUST NOT

/*** Logging ***/

#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
extern unsigned dhcp_verbose;
# define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
# define log1s(msg) do { if (dhcp_verbose >= 1) bb_simple_info_msg(msg); } while (0)
# if CONFIG_UDHCP_DEBUG >= 2
void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
#  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
#  define log2s(msg) do { if (dhcp_verbose >= 2) bb_simple_info_msg(msg); } while (0)
# else
#  define udhcp_dump_packet(...) ((void)0)
#  define log2(...) ((void)0)
#  define log2s(msg) ((void)0)
# endif
# if CONFIG_UDHCP_DEBUG >= 3
#  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
#  define log3s(msg) do { if (dhcp_verbose >= 3) bb_simple_info_msg(msg); } while (0)
# else
#  define log3(...) ((void)0)
#  define log3s(msg) ((void)0)
# endif
#else
# define IF_UDHCP_VERBOSE(...)
# define udhcp_dump_packet(...) ((void)0)
# define log1(...) ((void)0)
# define log1s(msg) ((void)0)
# define log2(...) ((void)0)
# define log2s(msg) ((void)0)
# define log3(...) ((void)0)
# define log3s(msg) ((void)0)
#endif

#if defined(__mips__)
/*
 * The 'simple' message functions have a negative impact on the size of the
 * DHCP code when compiled for MIPS, so don't use them in this case.
 */
#define bb_simple_info_msg bb_info_msg
#define bb_simple_error_msg bb_error_msg
#define bb_simple_perror_msg_and_die bb_perror_msg_and_die
#undef log1s
#define log1s log1
#endif

/*** Other shared functions ***/

/* 2nd param is "uint32_t*" */
int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
/* 2nd param is "struct option_set**" */
#if !ENABLE_UDHCPC6
#define udhcp_str2optset(str, arg, optflags, option_strings, dhcpv6) \
	udhcp_str2optset(str, arg, optflags, option_strings)
#endif
int FAST_FUNC udhcp_str2optset(const char *str,
		void *arg,
		const struct dhcp_optflag *optflags,
		const char *option_strings,
		bool dhcpv6);

#if ENABLE_UDHCPC || ENABLE_UDHCPD
void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
#endif

int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;

int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
		uint32_t source_nip, int source_port,
		uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
		int ifindex) FAST_FUNC;

int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
		uint32_t source_nip, int source_port,
		uint32_t dest_nip, int dest_port) FAST_FUNC;

void udhcp_sp_setup(void) FAST_FUNC;
void udhcp_sp_fd_set(struct pollfd *pfds, int extra_fd) FAST_FUNC;
int udhcp_sp_read(void) FAST_FUNC;

int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;

int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;

/* Returns 1 if no reply received */
int arpping(uint32_t test_nip,
		const uint8_t *safe_mac,
		uint32_t from_ip,
		uint8_t *from_mac,
		const char *interface,
		unsigned timeo) FAST_FUNC;

/* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
int sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) FAST_FUNC;

POP_SAVED_FUNCTION_VISIBILITY

#endif