resolv.h

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#ifndef _GPXE_RESOLV_H
#define _GPXE_RESOLV_H

/** @file
 *
 * Name resolution
 *
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <gpxe/refcnt.h>
#include <gpxe/interface.h>
#include <gpxe/tables.h>
#include <gpxe/socket.h>

struct resolv_interface;

/** Name resolution interface operations */
struct resolv_interface_operations {
        /** Name resolution completed
         *
         * @v resolv            Name resolution interface
         * @v sa                Completed socket address (if successful)
         * @v rc                Final status code
         */
        void ( * done ) ( struct resolv_interface *resolv,
                          struct sockaddr *sa, int rc );
};

/** A name resolution interface */
struct resolv_interface {
        /** Generic object communication interface */
        struct interface intf;
        /** Operations for received messages */
        struct resolv_interface_operations *op;
};

extern struct resolv_interface null_resolv;
extern struct resolv_interface_operations null_resolv_ops;

/**
 * Initialise a name resolution interface
 *
 * @v resolv            Name resolution interface
 * @v op                Name resolution interface operations
 * @v refcnt            Containing object reference counter, or NULL
 */
static inline void resolv_init ( struct resolv_interface *resolv,
                                 struct resolv_interface_operations *op,
                                 struct refcnt *refcnt ) {
        resolv->intf.dest = &null_resolv.intf;
        resolv->intf.refcnt = refcnt;
        resolv->op = op;
}

/**
 * Get name resolution interface from generic object communication interface
 *
 * @v intf              Generic object communication interface
 * @ret resolv          Name resolution interface
 */
static inline __attribute__ (( always_inline )) struct resolv_interface *
intf_to_resolv ( struct interface *intf ) {
        return container_of ( intf, struct resolv_interface, intf );
}

/**
 * Get reference to destination name resolution interface
 *
 * @v resolv            Name resolution interface
 * @ret dest            Destination interface
 */
static inline __attribute__ (( always_inline )) struct resolv_interface *
resolv_get_dest ( struct resolv_interface *resolv ) {
        return intf_to_resolv ( intf_get ( resolv->intf.dest ) );
}

/**
 * Drop reference to name resolution interface
 *
 * @v resolv            name resolution interface
 */
static inline __attribute__ (( always_inline )) void
resolv_put ( struct resolv_interface *resolv ) {
        intf_put ( &resolv->intf );
}

/**
 * Plug a name resolution interface into a new destination interface
 *
 * @v resolv            Name resolution interface
 * @v dest              New destination interface
 */
static inline __attribute__ (( always_inline )) void
resolv_plug ( struct resolv_interface *resolv, struct resolv_interface *dest ) {
        plug ( &resolv->intf, &dest->intf );
}

/**
 * Plug two name resolution interfaces together
 *
 * @v a                 Name resolution interface A
 * @v b                 Name resolution interface B
 */
static inline __attribute__ (( always_inline )) void
resolv_plug_plug ( struct resolv_interface *a, struct resolv_interface *b ) {
        plug_plug ( &a->intf, &b->intf );
}

/**
 * Unplug a name resolution interface
 *
 * @v resolv            Name resolution interface
 */
static inline __attribute__ (( always_inline )) void
resolv_unplug ( struct resolv_interface *resolv ) {
        plug ( &resolv->intf, &null_resolv.intf );
}

/**
 * Stop using a name resolution interface
 *
 * @v resolv            Name resolution interface
 *
 * After calling this method, no further messages will be received via
 * the interface.
 */
static inline void resolv_nullify ( struct resolv_interface *resolv ) {
        resolv->op = &null_resolv_ops;
};

/** A name resolver */
struct resolver {
        /** Name of this resolver (e.g. "DNS") */
        const char *name;
        /** Start name resolution
         *
         * @v resolv            Name resolution interface
         * @v name              Name to resolve
         * @v sa                Socket address to complete
         * @ret rc              Return status code
         */
        int ( * resolv ) ( struct resolv_interface *resolv, const char *name,
                           struct sockaddr *sa );
};

/** Numeric resolver priority */
#define RESOLV_NUMERIC 01

/** Normal resolver priority */
#define RESOLV_NORMAL 02

/** Resolvers table */
#define RESOLVERS __table ( struct resolver, "resolvers" )

/** Register as a name resolver */
#define __resolver( resolv_order ) __table_entry ( RESOLVERS, resolv_order )

extern void resolv_done ( struct resolv_interface *resolv,
                          struct sockaddr *sa, int rc );
extern void ignore_resolv_done ( struct resolv_interface *resolv,
                          struct sockaddr *sa, int rc );
extern struct resolv_interface_operations null_resolv_ops;
extern struct resolv_interface null_resolv;

extern int resolv ( struct resolv_interface *resolv, const char *name,
                    struct sockaddr *sa );

#endif /* _GPXE_RESOLV_H */