networking/udhcp/dhcpd.h

/* vi: set sw=4 ts=4: */
/* dhcpd.h */
#ifndef _DHCPD_H
#define _DHCPD_H

/************************************/
/* Defaults _you_ may want to tweak */
/************************************/

/* the period of time the client is allowed to use that address */
#define LEASE_TIME              (60*60*24*10) /* 10 days of seconds */
#define LEASES_FILE		"/var/lib/misc/udhcpd.leases"

/* where to find the DHCP server configuration file */
#define DHCPD_CONF_FILE         "/etc/udhcpd.conf"

/*****************************************************************/
/* Do not modify below here unless you know what you are doing!! */
/*****************************************************************/

/* DHCP protocol -- see RFC 2131 */
#define SERVER_PORT		67
#define CLIENT_PORT		68

#define DHCP_MAGIC		0x63825363

/* DHCP option codes (partial list) */
#define DHCP_PADDING		0x00
#define DHCP_SUBNET		0x01
#define DHCP_TIME_OFFSET	0x02
#define DHCP_ROUTER		0x03
#define DHCP_TIME_SERVER	0x04
#define DHCP_NAME_SERVER	0x05
#define DHCP_DNS_SERVER		0x06
#define DHCP_LOG_SERVER		0x07
#define DHCP_COOKIE_SERVER	0x08
#define DHCP_LPR_SERVER		0x09
#define DHCP_HOST_NAME		0x0c
#define DHCP_BOOT_SIZE		0x0d
#define DHCP_DOMAIN_NAME	0x0f
#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_NTP_SERVER		0x2a
#define DHCP_WINS_SERVER	0x2c
#define DHCP_REQUESTED_IP	0x32
#define DHCP_LEASE_TIME		0x33
#define DHCP_OPTION_OVER	0x34
#define DHCP_MESSAGE_TYPE	0x35
#define DHCP_SERVER_ID		0x36
#define DHCP_PARAM_REQ		0x37
#define DHCP_MESSAGE		0x38
#define DHCP_MAX_SIZE		0x39
#define DHCP_T1			0x3a
#define DHCP_T2			0x3b
#define DHCP_VENDOR		0x3c
#define DHCP_CLIENT_ID		0x3d
#define DHCP_FQDN		0x51

#define DHCP_END		0xFF


#define BOOTREQUEST		1
#define BOOTREPLY		2

#define ETH_10MB		1
#define ETH_10MB_LEN		6

#define DHCPDISCOVER		1
#define DHCPOFFER		2
#define DHCPREQUEST		3
#define DHCPDECLINE		4
#define DHCPACK			5
#define DHCPNAK			6
#define DHCPRELEASE		7
#define DHCPINFORM		8

#define BROADCAST_FLAG		0x8000

#define OPTION_FIELD		0
#define FILE_FIELD		1
#define SNAME_FIELD		2

/* miscellaneous defines */
#define MAC_BCAST_ADDR		(uint8_t *) "\xff\xff\xff\xff\xff\xff"
#define OPT_CODE 0
#define OPT_LEN 1
#define OPT_DATA 2

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

struct static_lease {
	uint8_t *mac;
	uint32_t *ip;
	struct static_lease *next;
};

struct server_config_t {
	uint32_t server;		/* Our IP, in network order */
	uint32_t start;			/* Start address of leases, network order */
	uint32_t end;			/* End of leases, network order */
	struct option_set *options;	/* List of DHCP options loaded from the config file */
	char *interface;		/* The name of the interface to use */
	int ifindex;			/* Index number of the interface to use */
	uint8_t arp[6];			/* Our arp address */
	unsigned long lease;		/* lease time in seconds (host order) */
	unsigned long max_leases;	/* maximum number of leases (including reserved address) */
	char remaining;			/* should the lease file be interpreted as lease time remaining, or
					 * as the time the lease expires */
	unsigned long auto_time;	/* how long should udhcpd wait before writing a config file.
					 * if this is zero, it will only write one on SIGUSR1 */
	unsigned long decline_time;	/* how long an address is reserved if a client returns a
					 * decline message */
	unsigned long conflict_time;	/* how long an arp conflict offender is leased for */
	unsigned long offer_time;	/* how long an offered address is reserved */
	unsigned long min_lease;	/* minimum lease a client can request*/
	char *lease_file;
	char *pidfile;
	char *notify_file;		/* What to run whenever leases are written */
	uint32_t siaddr;		/* next server bootp option */
	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 */
};

extern struct server_config_t server_config;
extern struct dhcpOfferedAddr *leases;


/*** leases.h ***/

struct dhcpOfferedAddr {
	uint8_t chaddr[16];
	uint32_t yiaddr;	/* network order */
	uint32_t expires;	/* host order */
};

extern uint8_t blank_chaddr[];

void clear_lease(uint8_t *chaddr, uint32_t yiaddr);
struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease);
int lease_expired(struct dhcpOfferedAddr *lease);
struct dhcpOfferedAddr *oldest_expired_lease(void);
struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr);
struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr);
uint32_t find_address(int check_expired);


/*** static_leases.h ***/

/* Config file will pass static lease info to this function which will add it
 * to a data structure that can be searched later */
int addStaticLease(struct static_lease **lease_struct, uint8_t *mac, uint32_t *ip);
/* Check to see if a mac has an associated static lease */
uint32_t getIpByMac(struct static_lease *lease_struct, void *arg);
/* Check to see if an ip is reserved as a static ip */
uint32_t reservedIp(struct static_lease *lease_struct, uint32_t ip);
/* Print out static leases just to check what's going on (debug code) */
void printStaticLeases(struct static_lease **lease_struct);


/*** serverpacket.h ***/

int sendOffer(struct dhcpMessage *oldpacket);
int sendNAK(struct dhcpMessage *oldpacket);
int sendACK(struct dhcpMessage *oldpacket, uint32_t yiaddr);
int send_inform(struct dhcpMessage *oldpacket);


/*** files.h ***/

struct config_keyword {
	const char *keyword;
	int (* const handler)(const char *line, void *var);
	void *var;
	const char *def;
};

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


#endif