alias_mod.h revision 190841 
1/*-
2 * Copyright (c) 2005 Paolo Pisati <piso@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/netinet/libalias/alias_mod.h 190841 2009-04-08 11:56:49Z piso $
27 */
28
29/*
30 * Alias_mod.h defines the outside world interfaces for the packet aliasing
31 * modular framework
32 */
33
34#ifndef _ALIAS_MOD_H_
35#define _ALIAS_MOD_H_
36
37#ifdef _KERNEL
38MALLOC_DECLARE(M_ALIAS);
39
40/* Use kernel allocator. */
41#if defined(_SYS_MALLOC_H_)
42#define	malloc(x)	malloc(x, M_ALIAS, M_NOWAIT|M_ZERO)
43#define	calloc(x, n)	malloc(x*n)
44#define	free(x)		free(x, M_ALIAS)
45#endif
46#endif
47
48/* Protocol handlers struct & function. */
49
50/* Packet flow direction. */
51#define IN                              1
52#define OUT                             2
53
54/* Working protocol. */
55#define IP                              1
56#define TCP                             2
57#define UDP                             4
58
59/*
60 * Data passed to protocol handler module, it must be filled
61 * right before calling find_handler() to determine which
62 * module is elegible to be called.
63 */
64
65struct alias_data {
66	struct alias_link       *lnk;
67	struct in_addr          *oaddr;         /* Original address. */
68	struct in_addr          *aaddr;         /* Alias address. */
69	uint16_t                *aport;         /* Alias port. */
70	uint16_t                *sport, *dport;	/* Source & destination port */
71	uint16_t                maxpktsize;     /* Max packet size. */
72};
73
74/*
75 * This structure contains all the information necessary to make
76 * a protocol handler correctly work.
77 */
78
79struct proto_handler {
80	u_int pri;                                              /* Handler priority. */
81        int16_t dir;                                            /* Flow direction. */
82	uint8_t proto;                                          /* Working protocol. */
83	int (*fingerprint)(struct libalias *,                   /* Fingerprint * function. */
84	    struct alias_data *);
85	int (*protohandler)(struct libalias *,                  /* Aliasing * function. */
86	    struct ip *, struct alias_data *);
87	LIST_ENTRY(proto_handler) entries;
88};
89
90
91/*
92 * Used only in userland when libalias needs to keep track of all
93 * module loaded. In kernel land (kld mode) we don't need to care
94 * care about libalias modules cause it's kld to do it for us.
95 */
96
97#define DLL_LEN         32
98struct dll {
99	char            name[DLL_LEN];  /* Name of module. */
100	void            *handle;        /*
101					 * Ptr to shared obj obtained through
102					 * dlopen() - use this ptr to get access
103					 * to any symbols from a loaded module
104					 * via dlsym().
105					 */
106	SLIST_ENTRY(dll)        next;
107};
108
109/* Functions used with protocol handlers. */
110
111void            handler_chain_init(void);
112void            handler_chain_destroy(void);
113int             LibAliasAttachHandlers(struct proto_handler *);
114int             LibAliasDetachHandlers(struct proto_handler *);
115int             detach_handler(struct proto_handler *);
116int             find_handler(int8_t, int8_t, struct libalias *,
117			   struct ip *, struct alias_data *);
118struct proto_handler *first_handler(void);
119
120/* Functions used with dll module. */
121
122void            dll_chain_init(void);
123void            dll_chain_destroy(void);
124int             attach_dll(struct dll *);
125void            *detach_dll(char *);
126struct dll      *walk_dll_chain(void);
127
128/* End of handlers. */
129#define EOH     -1
130
131/*
132 * Some defines borrowed from sys/module.h used to compile a kld
133 * in userland as a shared lib.
134 */
135
136#ifndef _KERNEL
137typedef enum modeventtype {
138        MOD_LOAD,
139        MOD_UNLOAD,
140        MOD_SHUTDOWN,
141        MOD_QUIESCE
142} modeventtype_t;
143
144typedef struct module *module_t;
145typedef int (*modeventhand_t)(module_t, int /* modeventtype_t */, void *);
146
147/*
148 * Struct for registering modules statically via SYSINIT.
149 */
150typedef struct moduledata {
151        const char      *name;          /* module name */
152        modeventhand_t  evhand;         /* event handler */
153        void            *priv;          /* extra data */
154} moduledata_t;
155#endif
156
157#endif				/* !_ALIAS_MOD_H_ */
158