handlers.h

/*
 * netlink/handlers.c   default netlink message handlers
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation version 2.1
 *      of the License.
 *
 * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
 */
 
#ifndef NETLINK_HANDLERS_H_
#define NETLINK_HANDLERS_H_
 
#include <stdio.h>
#include <stdint.h>
#include <sys/types.h>
#include <netlink/netlink-compat.h>
#include <netlink/netlink-kernel.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct nl_cb;
struct nl_handle;
struct nl_msg;
struct ucred;
 
/**
 * @name Callback Typedefs
 * @{
 */
 
/**
 * nl_recvmsgs() callback for message processing customization
 * @ingroup cb
 * @arg msg             netlink message being processed
 * @arg arg             argument passwd on through caller
 */
typedef int (*nl_recvmsg_msg_cb_t)(struct nl_msg *msg, void *arg);
 
/**
 * nl_recvmsgs() callback for error message processing customization
 * @ingroup cb
 * @arg nla             netlink address of the peer
 * @arg nlerr           netlink error message being processed
 * @arg arg             argument passed on through caller
 */
typedef int (*nl_recvmsg_err_cb_t)(struct sockaddr_nl *nla,
                                   struct nlmsgerr *nlerr, void *arg);
 
/** @} */
 
/**
 * Callback actions
 * @ingroup cb
 */
enum nl_cb_action {
        /** Proceed with wathever would come next */
        NL_OK,
        /** Skip this message */
        NL_SKIP,
        /** Stop parsing altogether and discard remaining messages */
        NL_STOP,
};
 
/* backwards compatibility */
#define NL_PROCEED NL_OK
#define NL_EXIT NL_STOP
 
/**
 * Callback kinds
 * @ingroup cb
 */
enum nl_cb_kind {
        /** Default handlers (quiet) */
        NL_CB_DEFAULT,
        /** Verbose default handlers (error messages printed) */
        NL_CB_VERBOSE,
        /** Debug handlers for debugging */
        NL_CB_DEBUG,
        /** Customized handler specified by the user */
        NL_CB_CUSTOM,
        __NL_CB_KIND_MAX,
};
 
#define NL_CB_KIND_MAX (__NL_CB_KIND_MAX - 1)
 
/**
 * Callback types
 * @ingroup cb
 */
enum nl_cb_type {
        /** Message is valid */
        NL_CB_VALID,
        /** Last message in a series of multi part messages received */
        NL_CB_FINISH,
        /** Report received that data was lost */
        NL_CB_OVERRUN,
        /** Message wants to be skipped */
        NL_CB_SKIPPED,
        /** Message is an acknowledge */
        NL_CB_ACK,
        /** Called for every message received */
        NL_CB_MSG_IN,
        /** Called for every message sent out except for nl_sendto() */
        NL_CB_MSG_OUT,
        /** Message is malformed and invalid */
        NL_CB_INVALID,
        /** Called instead of internal sequence number checking */
        NL_CB_SEQ_CHECK,
        /** Sending of an acknowledge message has been requested */
        NL_CB_SEND_ACK,
        __NL_CB_TYPE_MAX,
};
 
#define NL_CB_TYPE_MAX (__NL_CB_TYPE_MAX - 1)
 
extern struct nl_cb *   nl_cb_alloc(enum nl_cb_kind);
extern struct nl_cb *   nl_cb_clone(struct nl_cb *);
extern struct nl_cb *   nl_cb_get(struct nl_cb *);
extern void             nl_cb_put(struct nl_cb *);
 
extern int  nl_cb_set(struct nl_cb *, enum nl_cb_type, enum nl_cb_kind,
                      nl_recvmsg_msg_cb_t, void *);
extern int  nl_cb_set_all(struct nl_cb *, enum nl_cb_kind,
                          nl_recvmsg_msg_cb_t, void *);
extern int  nl_cb_err(struct nl_cb *, enum nl_cb_kind, nl_recvmsg_err_cb_t,
                      void *);
 
extern void nl_cb_overwrite_recvmsgs(struct nl_cb *,
                                     int (*func)(struct nl_handle *,
                                                 struct nl_cb *));
extern void nl_cb_overwrite_recv(struct nl_cb *,
                                 int (*func)(struct nl_handle *,
                                             struct sockaddr_nl *,
                                             unsigned char **,
                                             struct ucred **));
extern void nl_cb_overwrite_send(struct nl_cb *,
                                 int (*func)(struct nl_handle *,
                                             struct nl_msg *));
 
#ifdef __cplusplus
}
#endif
 
#endif