/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Paolo Pisati <piso@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Alias_mod.h defines the outside world interfaces for the packet aliasing
 * modular framework
 */

#ifndef _ALIAS_MOD_H_
#define _ALIAS_MOD_H_

#ifdef _KERNEL
MALLOC_DECLARE(M_ALIAS);

/* Use kernel allocator. */
#if defined(_SYS_MALLOC_H_)
#undef malloc
#define malloc(x)       malloc(x, M_ALIAS, M_NOWAIT|M_ZERO)
#define calloc(n, x)    mallocarray((n), (x), M_ALIAS, M_NOWAIT|M_ZERO)
#define free(x)         free(x, M_ALIAS)
#endif
#endif

/* Packet flow direction flags. */
#define IN      0x0001
#define OUT     0x0002
#define NODIR   0x4000

/* Working protocol flags. */
#define IP      0x01
#define TCP     0x02
#define UDP     0x04

/*
 * Data passed to protocol handler module, it must be filled
 * right before calling find_handler() to determine which
 * module is elegible to be called.
 */
struct alias_data {
        struct alias_link       *lnk;
        struct in_addr          *oaddr;         /* Original address. */
        struct in_addr          *aaddr;         /* Alias address. */
        uint16_t                *aport;         /* Alias port. */
        uint16_t                *sport, *dport; /* Source & destination port */
        uint16_t                maxpktsize;     /* Max packet size. */
};

/*
 * This structure contains all the information necessary to make
 * a protocol handler correctly work.
 */
struct proto_handler {
        u_int pri;              /* Handler priority. */
        int16_t dir;            /* Flow direction. */
        uint8_t proto;          /* Working protocol. */
        /* Fingerprint * function. */
        int (*fingerprint)(struct libalias *, struct alias_data *);
        /* Aliasing * function. */
        int (*protohandler)(struct libalias *, struct ip *,
            struct alias_data *);
        TAILQ_ENTRY(proto_handler) link;
};

/* End of handlers. */
#define EOH     .dir = NODIR

/* Functions used with protocol handlers. */
int LibAliasAttachHandlers(struct proto_handler *);
int LibAliasDetachHandlers(struct proto_handler *);
int find_handler(int8_t, int8_t, struct libalias *, struct ip *,
    struct alias_data *);
struct proto_handler *first_handler(void);

#ifndef _KERNEL
/*
 * Used only in userland when libalias needs to keep track of all
 * module loaded. In kernel land (kld mode) we don't need to care
 * care about libalias modules cause it's kld to do it for us.
 */
#define DLL_LEN  32
struct dll {
        char    name[DLL_LEN];  /* Name of module. */
        void    *handle;        /*
                                 * Ptr to shared obj obtained through
                                 * dlopen() - use this ptr to get access
                                 * to any symbols from a loaded module
                                 * via dlsym().
                                 */
        SLIST_ENTRY(dll)        next;
};

/* Functions used with dll module. */
void dll_chain_init(void);
void dll_chain_destroy(void);
int attach_dll(struct dll *);
void *detach_dll(char *);
struct dll *walk_dll_chain(void);

/*
 * Some defines borrowed from sys/module.h used to compile a kld
 * in userland as a shared lib.
 */
typedef enum modeventtype {
        MOD_LOAD,
        MOD_UNLOAD,
        MOD_SHUTDOWN,
        MOD_QUIESCE
} modeventtype_t;

typedef struct module *module_t;
typedef int (*modeventhand_t)(module_t, int /* modeventtype_t */, void *);

/*
 * Struct for registering modules statically via SYSINIT.
 */
typedef struct moduledata {
        const char      *name;  /* module name */
        modeventhand_t  evhand; /* event handler */
        void            *priv;  /* extra data */
} moduledata_t;
#endif /* !_KERNEL */

#endif /* !_ALIAS_MOD_H_ */