This application is a quick'n'dirty hack for registering, disseminating, and looking up services.

A service is identified by an 8-bit integer between 1 and 255. Integers below 128 are reserved for system services.

A service is registered with the function servreg_hack_register(). Registered services will be transmitted to all neighbors that run the servreg-hack application. These will in turn resend the registration to their neighbors.

Services from neighbors are stored in a local table. Services stored in the table can be looked up using a combination of the servreg_hack_list() and servreg_hack_item_match() functions.

Data Structures
struct	servreg_hack_registration

Files
file	servreg-hack.c
	Implementation of the servreg-hack application

file	servreg-hack.h
	Header file for the servreg-hack application

Macros
#define	LIFETIME 10 * 60 * CLOCK_SECOND

#define	MAX_BUFSIZE 2 + 80

#define	MAX_REGISTRATIONS 16

#define	MSG_ADDRS_LEN 20

#define	MSG_ADDRS_OFFSET 2

#define	MSG_FLAGS_OFFSET 1

#define	MSG_IPADDR_SUBOFFSET 0

#define	MSG_NUMREGS_OFFSET 0

#define	MSG_REGS_SUBOFFSET 16

#define	MSG_SEQNO_SUBOFFSET 19

#define	NEW_REG_TIME 10 * CLOCK_SECOND

#define	PERIOD_TIME 40 * CLOCK_SECOND

#define	SEQNO_LT(a, b) ((signed char)((a) - (b)) < 0)

#define	UDP_PORT 61616

Typedefs
typedef uint8_t	servreg_hack_id_t

typedef void	servreg_hack_item_t

Functions
static void	handle_incoming_reg (const uip_ipaddr_t *owner, servreg_hack_id_t id, uint8_t seqno)

	LIST (others_services)

	LIST (own_services)

	MEMB (registrations, struct servreg_hack_registration, MAX_REGISTRATIONS)

static void	parse_incoming_packet (const uint8_t *buf, int len)

	PROCESS (servreg_hack_process,"Service regstry hack")

	PROCESS_THREAD (servreg_hack_process, ev, data)

static void	purge_registrations (void)

static void	send_udp_packet (struct uip_udp_conn *conn)

void	servreg_hack_init (void)
	Initialize and start the servreg-hack application. More...

uip_ipaddr_t *	servreg_hack_item_address (servreg_hack_item_t *item)
	Get the IP address for a list item. More...

servreg_hack_id_t	servreg_hack_item_id (servreg_hack_item_t *item)
	Get the service ID for a list item. More...

servreg_hack_item_t *	servreg_hack_list_head (void)
	Obtain the list of services provided by neighbors. More...

uip_ipaddr_t *	servreg_hack_lookup (servreg_hack_id_t service_id)
	Get the IP address of a node offering a service. More...

void	servreg_hack_register (servreg_hack_id_t service_id, const uip_ipaddr_t *addr)
	Register that this node provides a service. More...

Variables
uip_ipaddr_t	servreg_hack_registration::addr

servreg_hack_id_t	servreg_hack_registration::id

struct servreg_hack_registration *	servreg_hack_registration::next

static struct etimer	sendtimer

uint8_t	servreg_hack_registration::seqno

static uint8_t	started = 0

struct timer	servreg_hack_registration::timer

#define LIFETIME 10 * 60 * CLOCK_SECOND

Referenced by handle_incoming_reg(), purge_registrations(), and servreg_hack_register().

#define MAX_BUFSIZE 2 + 80

Referenced by send_udp_packet().

#define MAX_REGISTRATIONS 16

#define MSG_ADDRS_LEN 20

Referenced by send_udp_packet().

#define MSG_ADDRS_OFFSET 2

Referenced by parse_incoming_packet(), and send_udp_packet().

#define MSG_FLAGS_OFFSET 1

Referenced by parse_incoming_packet(), and send_udp_packet().

#define MSG_IPADDR_SUBOFFSET 0

Referenced by parse_incoming_packet(), and send_udp_packet().

#define MSG_NUMREGS_OFFSET 0

Referenced by parse_incoming_packet(), and send_udp_packet().

#define MSG_REGS_SUBOFFSET 16

Referenced by parse_incoming_packet(), and send_udp_packet().

#define MSG_SEQNO_SUBOFFSET 19

Referenced by parse_incoming_packet(), and send_udp_packet().

#define NEW_REG_TIME 10 * CLOCK_SECOND

Referenced by servreg_hack_register().

#define PERIOD_TIME 40 * CLOCK_SECOND

Referenced by PROCESS_THREAD().

#define SEQNO_LT	(	a,
		b
	)	((signed char)((a) - (b)) < 0)

Referenced by handle_incoming_reg().

#define UDP_PORT 61616

Referenced by PROCESS_THREAD().

typedef uint8_t servreg_hack_id_t

typedef void servreg_hack_item_t

static void handle_incoming_reg	(	const uip_ipaddr_t *	owner,
		servreg_hack_id_t	id,
		uint8_t	seqno
	)

static

References servreg_hack_registration::addr, servreg_hack_registration::id, id, LIFETIME, list_add(), list_item_next(), list_push(), list_remove(), memb_alloc(), NULL, printf, servreg_hack_registration::seqno, SEQNO_LT, servreg_hack_item_id(), servreg_hack_list_head(), servreg_hack_registration::timer, timer_set(), and uip_ipaddr_copy.

Referenced by parse_incoming_packet().

LIST ( others_services )

LIST ( own_services )

MEMB	(	registrations	,
		struct servreg_hack_registration	,
		MAX_REGISTRATIONS
	)

static void parse_incoming_packet	(	const uint8_t *	buf,
		int	len
	)

static

References bufptr, handle_incoming_reg(), i, MSG_ADDRS_OFFSET, MSG_FLAGS_OFFSET, MSG_IPADDR_SUBOFFSET, MSG_NUMREGS_OFFSET, MSG_REGS_SUBOFFSET, and MSG_SEQNO_SUBOFFSET.

Referenced by PROCESS_THREAD().

PROCESS	(	servreg_hack_process	,
		"Service regstry hack"
	)

PROCESS_THREAD	(	servreg_hack_process	,
		ev	,
		data
	)

static void purge_registrations ( void )

static

References LIFETIME, list_head(), list_item_next(), list_remove(), memb_free(), NULL, servreg_hack_registration::seqno, servreg_hack_registration::timer, timer_expired(), and timer_set().

Referenced by servreg_hack_list_head(), and servreg_hack_lookup().

static void send_udp_packet ( struct uip_udp_conn * conn )

static

References buf, bufptr, list_head(), list_item_next(), MAX_BUFSIZE, MSG_ADDRS_LEN, MSG_ADDRS_OFFSET, MSG_FLAGS_OFFSET, MSG_IPADDR_SUBOFFSET, MSG_NUMREGS_OFFSET, MSG_REGS_SUBOFFSET, MSG_SEQNO_SUBOFFSET, NULL, servreg_hack_item_address(), servreg_hack_item_id(), servreg_hack_list_head(), uip_ipaddr_copy, and uip_udp_packet_send().

Referenced by PROCESS_THREAD().

void servreg_hack_init ( void )

Initialize and start the servreg-hack application.

This function initializes and starts the servreg-hack application and daemon.

References list_init(), memb_init(), NULL, process_start(), and started.

Referenced by PROCESS_THREAD(), servreg_hack_lookup(), and servreg_hack_register().

uip_ipaddr_t * servreg_hack_item_address ( servreg_hack_item_t * item )

Get the IP address for a list item.

Parameters

item	The list item

Returns

The IP address

        This function is used when iterating through the list
        of registered services.

Referenced by send_udp_packet(), and servreg_hack_lookup().

servreg_hack_id_t servreg_hack_item_id ( servreg_hack_item_t * item )

Get the service ID for a list item.

Parameters

item	The list item

Returns

The service ID for a list item

        This function is used when iterating through the list
        of registered services.

Referenced by handle_incoming_reg(), send_udp_packet(), servreg_hack_lookup(), and servreg_hack_register().

servreg_hack_item_t * servreg_hack_list_head ( void )

Obtain the list of services provided by neighbors.

Returns

The list of services

        This function returns a list of services registered by
        other nodes. To find a specific service, the caller
        needs to iterate through the list and check each list
        item with the servreg_hack_item_match() function.

References list_head(), and purge_registrations().

Referenced by handle_incoming_reg(), send_udp_packet(), and servreg_hack_lookup().

uip_ipaddr_t * servreg_hack_lookup ( servreg_hack_id_t service_id )

Get the IP address of a node offering a service.

Parameters

service_id The service ID of the service

Returns

A pointer to the IP address of the node, or NULL if the service was not known

        This function returns the address of the node offering
        a specific service. If the service is not known, the
        function returns NULL. If there are more than one nodes
        offering the service, this function returns the address
        of the node that most recently announced its service.

        To get a list of all nodes offering a specific service,
        use the servreg_hack_list_head() function to get the
        full list of offered services.

References id, list_item_next(), NULL, purge_registrations(), servreg_hack_init(), servreg_hack_item_address(), servreg_hack_item_id(), and servreg_hack_list_head().

Referenced by PROCESS_THREAD().

void servreg_hack_register	(	servreg_hack_id_t	service_id,
		const uip_ipaddr_t *	addr
	)

Register that this node provides a service.

Parameters

service_id The 8-bit ID for the service

addr

The address associated with the service

        This function is used to register a
        service. Registering a service means that other nodes
        in the network will become aware that this node
        provides this service. The servreg-hack application
        does not specify what this service means, nor does it
        provide any mechanism by which the service can be
        reached: this is up to the application that uses the
        servreg-hack application.

References servreg_hack_registration::addr, etimer_set(), servreg_hack_registration::id, id, LIFETIME, list_head(), list_item_next(), list_push(), memb_alloc(), NEW_REG_TIME, NULL, printf, PROCESS_CONTEXT_BEGIN, PROCESS_CONTEXT_END, random_rand(), sendtimer, servreg_hack_registration::seqno, servreg_hack_init(), servreg_hack_item_id(), servreg_hack_registration::timer, timer_set(), and uip_ipaddr_copy.