summaryrefslogtreecommitdiff
path: root/networking/udhcp/dhcpd.h
blob: a4e9a58ff6ef52d3b4e061774f2286e68e0f7be7 (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
/* vi: set sw=4 ts=4: */
/* dhcpd.h */
#ifndef UDHCP_DHCPD_H
#define UDHCP_DHCPD_H 1

PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN

/* Defaults you may want to tweak */
/* Default max_lease_sec */
#define DEFAULT_LEASE_TIME      (60*60*24 * 10)
#define LEASES_FILE             CONFIG_DHCPD_LEASES_FILE
/* Where to find the DHCP server configuration file */
#define DHCPD_CONF_FILE         "/etc/udhcpd.conf"


struct static_lease {
	struct static_lease *next;
	uint32_t nip;
	uint8_t mac[6];
};

struct server_config_t {
	char *interface;                /* interface to use */
//TODO: ifindex, server_nip, server_mac
// are obtained from interface name.
// Instead of querying them *once*, create update_server_network_data_cache()
// and call it before any usage of these fields.
// update_server_network_data_cache() must re-query data
// if more than N seconds have passed after last use.
	int ifindex;
	uint32_t server_nip;
#if ENABLE_FEATURE_UDHCP_PORT
	uint16_t port;
#endif
	uint8_t server_mac[6];          /* our MAC address (used only for ARP probing) */
	struct option_set *options;     /* list of DHCP options loaded from the config file */
	/* start,end are in host order: we need to compare start <= ip <= end */
	uint32_t start_ip;              /* start address of leases, in host order */
	uint32_t end_ip;                /* end of leases, in host order */
	uint32_t max_lease_sec;         /* maximum lease time (host order) */
	uint32_t min_lease_sec;         /* minimum lease time a client can request */
	uint32_t max_leases;            /* maximum number of leases (including reserved addresses) */
	uint32_t auto_time;             /* how long should udhcpd wait before writing a config file.
	                                 * if this is zero, it will only write one on SIGUSR1 */
	uint32_t decline_time;          /* how long an address is reserved if a client returns a
	                                 * decline message */
	uint32_t conflict_time;         /* how long an arp conflict offender is leased for */
	uint32_t offer_time;            /* how long an offered address is reserved */
	uint32_t siaddr_nip;            /* "next server" bootp option */
	char *lease_file;
	char *pidfile;
	char *notify_file;              /* what to run whenever leases are written */
	char *sname;                    /* bootp server name */
	char *boot_file;                /* bootp boot file option */
	struct static_lease *static_leases; /* List of ip/mac pairs to assign static leases */
} FIX_ALIASING;

#define server_config (*(struct server_config_t*)&bb_common_bufsiz1)
/* client_config sits in 2nd half of bb_common_bufsiz1 */

#if ENABLE_FEATURE_UDHCP_PORT
#define SERVER_PORT (server_config.port)
#else
#define SERVER_PORT 67
#endif


/*** leases.h ***/

typedef uint32_t leasetime_t;
typedef int32_t signed_leasetime_t;

struct dyn_lease {
	/* "nip": IP in network order */
	/* Unix time when lease expires. Kept in memory in host order.
	 * When written to file, converted to network order
	 * and adjusted (current time subtracted) */
	leasetime_t expires;
	uint32_t lease_nip;
	/* We use lease_mac[6], since e.g. ARP probing uses
	 * only 6 first bytes anyway. We check received dhcp packets
	 * that their hlen == 6 and thus chaddr has only 6 significant bytes
	 * (dhcp packet has chaddr[16], not [6])
	 */
	uint8_t lease_mac[6];
	char hostname[20];
	uint8_t pad[2];
	/* total size is a multiply of 4 */
} PACKED;

extern struct dyn_lease *g_leases;

struct dyn_lease *add_lease(
		const uint8_t *chaddr, uint32_t yiaddr,
		leasetime_t leasetime,
		const char *hostname, int hostname_len
		) FAST_FUNC;
int is_expired_lease(struct dyn_lease *lease) FAST_FUNC;
struct dyn_lease *find_lease_by_mac(const uint8_t *mac) FAST_FUNC;
struct dyn_lease *find_lease_by_nip(uint32_t nip) FAST_FUNC;
uint32_t find_free_or_expired_nip(const uint8_t *safe_mac) FAST_FUNC;


/*** static_leases.h ***/

/* Config file parser will pass static lease info to this function
 * which will add it to a data structure that can be searched later */
void add_static_lease(struct static_lease **st_lease_pp, uint8_t *mac, uint32_t nip) FAST_FUNC;
/* Find static lease IP by mac */
uint32_t get_static_nip_by_mac(struct static_lease *st_lease, void *arg) FAST_FUNC;
/* Check to see if an IP is reserved as a static IP */
int is_nip_reserved(struct static_lease *st_lease, uint32_t nip) FAST_FUNC;
/* Print out static leases just to check what's going on (debug code) */
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
void log_static_leases(struct static_lease **st_lease_pp) FAST_FUNC;
#else
# define log_static_leases(st_lease_pp) ((void)0)
#endif


/*** files.h ***/

void read_config(const char *file) FAST_FUNC;
void write_leases(void) FAST_FUNC;
void read_leases(const char *file) FAST_FUNC;
struct option_set *find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;


POP_SAVED_FUNCTION_VISIBILITY

#endif