1/* SPDX-License-Identifier: BSD-2-Clause */
2/*
3 * dhcpcd - DHCP client daemon
4 * Copyright (c) 2006-2023 Roy Marples <roy@marples.name>
5 * All rights reserved
6
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef DHCP_H
30#define DHCP_H
31
32#include <arpa/inet.h>
33#include <netinet/in.h>
34
35#include <netinet/ip.h>
36#define __FAVOR_BSD /* Nasty glibc hack so we can use BSD semantics for UDP */
37#include <netinet/udp.h>
38#undef __FAVOR_BSD
39
40#include <limits.h>
41#include <stdint.h>
42
43#include "arp.h"
44#include "bpf.h"
45#include "auth.h"
46#include "dhcp-common.h"
47
48/* UDP port numbers for BOOTP */
49#define BOOTPS			67
50#define BOOTPC			68
51
52#define MAGIC_COOKIE		0x63825363
53#define BROADCAST_FLAG		0x8000
54
55/* BOOTP message OP code */
56#define BOOTREQUEST		1
57#define BOOTREPLY		2
58
59/* DHCP message type */
60#define DHCP_DISCOVER		1
61#define DHCP_OFFER		2
62#define DHCP_REQUEST		3
63#define DHCP_DECLINE		4
64#define DHCP_ACK		5
65#define DHCP_NAK		6
66#define DHCP_RELEASE		7
67#define DHCP_INFORM		8
68#define DHCP_FORCERENEW		9
69
70/* Constants taken from RFC 2131. */
71#define T1			0.5
72#define T2			0.875
73#define DHCP_BASE		4
74#define DHCP_MAX		64
75#define DHCP_RAND_MIN		-1
76#define DHCP_RAND_MAX		1
77
78#ifdef RFC2131_STRICT
79/* Be strictly conformant for section 4.1.1 */
80#  define DHCP_MIN_DELAY	1
81#  define DHCP_MAX_DELAY	10
82#else
83/* or mirror the more modern IPv6RS and DHCPv6 delays */
84#  define DHCP_MIN_DELAY	0
85#  define DHCP_MAX_DELAY	1
86#endif
87
88/* DHCP options */
89enum DHO {
90	DHO_PAD                    = 0,
91	DHO_SUBNETMASK             = 1,
92	DHO_ROUTER                 = 3,
93	DHO_DNSSERVER              = 6,
94	DHO_HOSTNAME               = 12,
95	DHO_DNSDOMAIN              = 15,
96	DHO_MTU                    = 26,
97	DHO_BROADCAST              = 28,
98	DHO_STATICROUTE            = 33,
99	DHO_NISDOMAIN              = 40,
100	DHO_NISSERVER              = 41,
101	DHO_NTPSERVER              = 42,
102	DHO_VENDOR                 = 43,
103	DHO_IPADDRESS              = 50,
104	DHO_LEASETIME              = 51,
105	DHO_OPTSOVERLOADED         = 52,
106	DHO_MESSAGETYPE            = 53,
107	DHO_SERVERID               = 54,
108	DHO_PARAMETERREQUESTLIST   = 55,
109	DHO_MESSAGE                = 56,
110	DHO_MAXMESSAGESIZE         = 57,
111	DHO_RENEWALTIME            = 58,
112	DHO_REBINDTIME             = 59,
113	DHO_VENDORCLASSID          = 60,
114	DHO_CLIENTID               = 61,
115	DHO_USERCLASS              = 77,  /* RFC 3004 */
116	DHO_RAPIDCOMMIT            = 80,  /* RFC 4039 */
117	DHO_FQDN                   = 81,
118	DHO_AUTHENTICATION         = 90,  /* RFC 3118 */
119	DHO_IPV6_PREFERRED_ONLY    = 108, /* RFC 8925 */
120	DHO_AUTOCONFIGURE          = 116, /* RFC 2563 */
121	DHO_DNSSEARCH              = 119, /* RFC 3397 */
122	DHO_CSR                    = 121, /* RFC 3442 */
123	DHO_VIVCO                  = 124, /* RFC 3925 */
124	DHO_VIVSO                  = 125, /* RFC 3925 */
125	DHO_FORCERENEW_NONCE       = 145, /* RFC 6704 */
126	DHO_MUDURL                 = 161, /* draft-ietf-opsawg-mud */
127	DHO_SIXRD                  = 212, /* RFC 5969 */
128	DHO_MSCSR                  = 249, /* MS code for RFC 3442 */
129	DHO_END                    = 255
130};
131
132/* FQDN values - lsnybble used in flags
133 * hsnybble to create order
134 * and to allow 0x00 to mean disable
135 */
136enum FQDN {
137	FQDN_DISABLE    = 0x00,
138	FQDN_NONE       = 0x18,
139	FQDN_PTR        = 0x20,
140	FQDN_BOTH       = 0x31
141};
142
143#define	MIN_V6ONLY_WAIT		300 /* seconds, RFC 8925 */
144
145/* Sizes for BOOTP options */
146#define	BOOTP_CHADDR_LEN	 16
147#define	BOOTP_SNAME_LEN		 64
148#define	BOOTP_FILE_LEN		128
149#define	BOOTP_VEND_LEN		 64
150
151/* DHCP is basically an extension to BOOTP */
152struct bootp {
153	uint8_t op;		/* message type */
154	uint8_t htype;		/* hardware address type */
155	uint8_t hlen;		/* hardware address length */
156	uint8_t hops;		/* should be zero in client message */
157	uint32_t xid;		/* transaction id */
158	uint16_t secs;		/* elapsed time in sec. from boot */
159	uint16_t flags;		/* such as broadcast flag */
160	uint32_t ciaddr;	/* (previously allocated) client IP */
161	uint32_t yiaddr;	/* 'your' client IP address */
162	uint32_t siaddr;	/* should be zero in client's messages */
163	uint32_t giaddr;	/* should be zero in client's messages */
164	uint8_t chaddr[BOOTP_CHADDR_LEN];	/* client's hardware address */
165	uint8_t sname[BOOTP_SNAME_LEN];		/* server host name */
166	uint8_t file[BOOTP_FILE_LEN];		/* boot file name */
167	uint8_t vend[BOOTP_VEND_LEN];		/* vendor specific area */
168	/* DHCP allows a variable length vendor area */
169};
170
171#define	DHCP_MIN_LEN		(offsetof(struct bootp, vend) + 4)
172
173struct bootp_pkt
174{
175	struct ip ip;
176	struct udphdr udp;
177	struct bootp bootp;
178};
179
180struct dhcp_lease {
181	struct in_addr addr;
182	struct in_addr mask;
183	struct in_addr brd;
184	uint32_t leasetime;
185	uint32_t renewaltime;
186	uint32_t rebindtime;
187	struct in_addr server;
188	uint8_t frominfo;
189	uint32_t cookie;
190};
191
192#ifndef DHCP_INFINITE_LIFETIME
193#  define DHCP_INFINITE_LIFETIME	(~0U)
194#endif
195
196enum DHS {
197	DHS_NONE,
198	DHS_INIT,
199	DHS_DISCOVER,
200	DHS_REQUEST,
201	DHS_PROBE,
202	DHS_BOUND,
203	DHS_RENEW,
204	DHS_REBIND,
205	DHS_REBOOT,
206	DHS_INFORM,
207	DHS_RENEW_REQUESTED,
208	DHS_RELEASE
209};
210
211struct dhcp_state {
212	enum DHS state;
213	struct bootp *sent;
214	size_t sent_len;
215	struct bootp *offer;
216	size_t offer_len;
217	struct bootp *new;
218	size_t new_len;
219	struct bootp *old;
220	size_t old_len;
221	struct dhcp_lease lease;
222	const char *reason;
223	unsigned int interval;
224	unsigned int nakoff;
225	uint32_t xid;
226	int socket;
227
228	struct bpf *bpf;
229	int udp_rfd;
230	struct ipv4_addr *addr;
231	uint8_t added;
232
233	char leasefile[sizeof(LEASEFILE) + IF_NAMESIZE + (IF_SSIDLEN * 4)];
234	struct timespec started;
235	unsigned char *clientid;
236	struct authstate auth;
237#ifdef ARPING
238	ssize_t arping_index;
239#endif
240};
241
242#ifdef INET
243#define D_STATE(ifp)							       \
244	((struct dhcp_state *)(ifp)->if_data[IF_DATA_DHCP])
245#define D_CSTATE(ifp)							       \
246	((const struct dhcp_state *)(ifp)->if_data[IF_DATA_DHCP])
247#define D_STATE_RUNNING(ifp)						       \
248	(D_CSTATE((ifp)) && D_CSTATE((ifp))->new && D_CSTATE((ifp))->reason)
249
250#define IS_DHCP(b)	((b)->vend[0] == 0x63 &&	\
251			 (b)->vend[1] == 0x82 &&	\
252			 (b)->vend[2] == 0x53 &&	\
253			 (b)->vend[3] == 0x63)
254
255#include "dhcpcd.h"
256#include "if-options.h"
257
258ssize_t print_rfc3361(FILE *, const uint8_t *, size_t);
259ssize_t print_rfc3442(FILE *, const uint8_t *, size_t);
260
261int dhcp_openudp(struct in_addr *);
262void dhcp_packet(struct interface *, uint8_t *, size_t, unsigned int);
263void dhcp_recvmsg(struct dhcpcd_ctx *, struct msghdr *);
264void dhcp_printoptions(const struct dhcpcd_ctx *,
265    const struct dhcp_opt *, size_t);
266uint16_t dhcp_get_mtu(const struct interface *);
267int dhcp_get_routes(rb_tree_t *, struct interface *);
268ssize_t dhcp_env(FILE *, const char *, const struct interface *,
269    const struct bootp *, size_t);
270
271struct ipv4_addr *dhcp_handleifa(int, struct ipv4_addr *, pid_t pid);
272void dhcp_drop(struct interface *, const char *);
273void dhcp_start(struct interface *);
274void dhcp_abort(struct interface *);
275void dhcp_discover(void *);
276void dhcp_inform(struct interface *);
277void dhcp_renew(struct interface *);
278void dhcp_bind(struct interface *);
279void dhcp_reboot_newopts(struct interface *, unsigned long long);
280void dhcp_close(struct interface *);
281void dhcp_free(struct interface *);
282int dhcp_dump(struct interface *);
283#endif /* INET */
284
285#endif /* DHCP_H */
286